JP5266176B2 - Planographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original lithographic printing plate which is excellent in resistance to plate wear/print smear and resistance to micro-corrosion stain and can develop an image aboard the machine. <P>SOLUTION: The original lithographic printing plate has an image recording layer comprising a sensitizing dye (A), a polymerization initiator (B), a polymerizable compound (C) and a polymer (D), on a support, wherein the image recording layer of an unexposed part is removed by a printing ink and/or moistening water. Therein, the support is made by using an aluminum alloy plate wherein the density, on the surface, of an inter-metallic compound having a circle-equivalent diameter of 0.2 &mu;m or more is 35,000 pieces/mm<SP>2</SP>or more. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a lithographic printing plate precursor. Specifically, the present invention relates to a lithographic printing plate precursor capable of on-press development.

  Numerous studies have been conducted on computer-to-plate (CTP) systems that have made remarkable progress in recent years. Among them, as an aim to further streamline the process and solve the waste liquid treatment problem, lithographic printing plate precursors that can be mounted on a printing machine and printed without being developed after exposure have been studied, and various methods have been proposed. Yes.

  One method of eliminating the processing step is to mount the exposed lithographic printing plate precursor on the plate cylinder of the printing press, and supply dampening water and ink while rotating the plate cylinder to remove the lithographic printing plate precursor. There is a method called on-machine development that removes the image area. That is, the lithographic printing plate precursor is exposed to light and mounted on a printing machine as it is, and development processing is completed in a normal printing process. A lithographic printing plate precursor suitable for on-press development has an image recording layer that is soluble in fountain solution or an ink solvent, and is bright when developed on a press in a bright room. It is required to have room handling properties.

  For example, Patent Document 1 describes a lithographic printing plate precursor in which an image recording layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. In this Patent Document 1, a lithographic printing plate precursor is subjected to laser exposure, and the thermoplastic hydrophobic polymer particles in the image recording layer are coalesced by heat to form an image, and then the plate is mounted on a plate cylinder of a printing press, It is described that an unexposed portion can be removed (on-press development) with fountain solution and / or ink. This lithographic printing plate precursor also has suitability for handling a bright room because the photosensitive region is an infrared region.

  Patent Document 2 discloses a lithographic printing plate having an image recording layer containing at least one of thermoplastic polymer fine particles, polymer fine particles having a thermoreactive group, and microcapsules encapsulating a compound having a thermoreactive group. It is described that the original plate has good on-press developability, high sensitivity and high printing resistance.

  However, the lithographic printing plate precursors described in Patent Documents 1 and 2 have spots where ink tends to adhere to a part of the surface of the non-image area when stored for a long period of time, and appear on printed paper or the like. Or annular dirt (hereinafter also referred to as “micro-corrosive dirt”) may occur.

Patent Documents 3 to 5 describe lithographic printing plate precursor supports focusing on the intermetallic compound of the support, and all are inventions relating to a support having 35000 intermetallic compounds / mm ² or less. .

Japanese Patent No. 2938397 JP 2001-293971 A JP 2002-160466 A Japanese Patent No. 3788943 JP 2002-88434 A

  The present inventor examined the cause of the occurrence of the micro-corrosion stains. First, the so-called on-press development type lithographic printing plate precursor described in Patent Documents 1 and 2 and the like is obtained using printing ink and / or fountain solution. Since a removable image recording layer is provided, there are many hydrophilic components in the image recording layer. As a result, the image recording layer easily contains moisture due to the influence of outside air or the like. Focused on being. And so-called on-press development type lithographic printing plate precursors described in Patent Documents 1 and 2, etc., include moisture contained in the image recording layer due to the influence of outside air, etc., and hydrophilic components anionized by the moisture (hereinafter, It was clarified that the presence of the “anion”) caused corrosion of the aluminum alloy plate, thereby causing minute corrosion stains.

On the other hand, regarding the intermetallic compound of the aluminum alloy plate, for example, JP 2005-330588 A, JP 2005-232596 A, JP 11-151870 A and the like are included in an aluminum alloy plate for a lithographic printing plate. Contents related to intermetallic compounds are described.
Specifically, the Al-Fe intermetallic compound is likely to be a starting point of pits during electrolytic surface roughening than the Al-Fe-Si intermetallic compound, and among the Al-Fe intermetallic compounds, It is described that a metastable phase Al—Fe-based intermetallic compound tends to be a starting point of pits. JP-A-2005-330588 discloses that the number of metastable phase particles having a Fe / Al ratio of 0.6 or less is 0.35 or more with respect to the total number of intermetallic compound particles. It is described that eyes form. Furthermore, Japanese Patent Application Laid-Open No. 2005-232596 describes an aluminum alloy plate containing 0.5 to 2.0% of an average AlFe-based crystal precipitate. Japanese Patent Laid-Open No. 11-151870 is characterized in that the ratio of the number of Al—Fe intermetallic compound particles / the number of Al—Fe—Si intermetallic compound particles is 0.7 or more.
However, these patent documents do not describe an intermetallic compound for suppressing corrosion of the aluminum substrate by the image recording layer.

  Accordingly, an object of the present invention is to provide a lithographic printing plate precursor excellent in printing durability, stain resistance and microcorrosion stain resistance, particularly a lithographic printing plate precursor having on-press developability having the above-mentioned characteristics. .

As a result of earnest research to achieve the above-mentioned object, the inventor uses a support made using an aluminum alloy plate having an intermetallic compound density of 35000 pieces / mm ² or more on the surface, thereby improving the printing durability, The inventors have found that it is possible to obtain an on-press developable lithographic printing plate precursor excellent in stain resistance and micro-corrosion stain resistance, and completed the present invention.
That is, the present invention provides the following (1) to (11).

(1) An image recording layer having (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a polymer on the support, and image recording in an unexposed area. In a lithographic printing plate precursor where the layer is removed with printing ink and / or fountain solution,
A lithographic printing plate precursor, wherein the support is prepared using an aluminum alloy plate having a density of an intermetallic compound having a circle-equivalent diameter of 0.2 µm or more on the surface of 35000 pieces / mm ² or more.

(2) The lithographic printing plate as described in (1) above, wherein the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface is 2500 pieces / mm ² or less. Original edition.

  (3) The lithographic printing plate precursor as described in (1) or (2) above, wherein an oxygen blocking layer is provided on the image recording layer.

  (4) The lithographic printing plate precursor as described in (1) or (2) above, which does not have an oxygen barrier layer on the image recording layer.

  (5) The lithographic printing plate precursor as described in any one of (1) to (4) above, wherein the polymer (D) has an alkylene oxide chain.

  (6) The lithographic printing plate precursor as described in any one of (1) to (5) above, wherein the polymer (D) is in the form of particles.

  (7) The peak count value of the Al—Fe-based intermetallic compound of the aluminum alloy plate, measured using an X-ray diffractometer (XRD), is 400 cps or less, (1) to (1) above 6) The lithographic printing plate precursor as described in any one of 6).

(8) is measured using X-ray diffraction apparatus (XRD), the peak count value of the AlFeSi intermetallic compound of the aluminum alloy sheet is characterized in that an on 30cps than the above (1) to (7 ) The lithographic printing plate precursor as described in any of the above.

  (9) An anodized film having micropores is formed on the surface of the support on which the image recording layer is formed, and the average pore diameter in the surface layer of the anodized film is 10 to 75 nm. The lithographic printing plate precursor as described in any one of (1) to (8) above, wherein the average value of the maximum diameter inside the pore is 1.1 to 3.0 times the average pore diameter.

  (10) The anodic oxide film is formed by an anodic oxidation treatment using an electrolytic solution containing sulfuric acid or phosphoric acid, according to any one of (1) to (9) above, Lithographic printing plate precursor.

  (11) The lithographic printing plate precursor as described in any one of (1) to (10) above, wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method.

  According to the present invention, an on-press developable lithographic printing plate precursor having excellent printing durability, stain resistance and micro-corrosion stain resistance can be obtained.

It is a graph which shows an example of the alternating waveform current waveform figure used for an electrochemical roughening process. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current. It is the schematic of the anodizing apparatus used for anodizing. It is a graph which shows an example of the sine waveform figure used for an electrochemical roughening process. It is a side view which shows the concept of the process of the brush graining used for a machine roughening process.

Hereinafter, the present invention will be described in detail.
The planographic printing plate precursor of the present invention has an image recording layer having (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a polymer on a support, In the lithographic printing plate precursor in which the image recording layer in the non-exposed area is removed with printing ink and / or fountain solution, the support has a density of 35,000 / intermetallic compound having a circle-equivalent diameter of 0.2 μm or more on the surface. It is produced using an aluminum alloy plate of mm ² or more.

As described above, in the case of a so-called on-press development type lithographic printing plate precursor, an image recording layer that can be removed by printing ink and / or dampening water is provided, so that many hydrophilic components are present in the image recording layer. As a result, moisture is likely to be included in the image recording layer due to the influence of outside air or the like. The presence of moisture contained in the image-recording layer due to the influence of outside air and the hydrophilic component anionized by the moisture (hereinafter simply referred to as “anion”) causes corrosion of the aluminum alloy plate, thereby Micro-corrosion contamination occurs.
The present inventor, when an intermetallic compound having a large equivalent circle diameter is present on the surface of the aluminum alloy plate, when the image recording layer contains many hydrophilic components, it is likely to become a starting point of corrosion of the aluminum alloy plate, and is equivalent to a circle. It was found that this tendency becomes remarkable when an intermetallic compound having a diameter of more than 1 μm is present.
If the density of the intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface is 35,000 / mm ² or more, the intermetallic compound having an equivalent circle diameter of more than 1 μm existing on the surface of the aluminum alloy plate Since the number is extremely small, the corrosion of the aluminum alloy plate and the resulting fine corrosion stains can be suppressed when the image recording layer contains many hydrophilic components.
From the viewpoint of suppressing minute corrosion stains, the density of the intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface of the aluminum alloy plate is preferably 50,000 pieces / mm ² or more.

In addition, new knowledge has been obtained that intermetallic compounds present on the surface of an aluminum alloy plate are effective starting points when electrochemically roughening the aluminum alloy plate. By using an aluminum alloy plate having an equivalent diameter of 0.2 μm or more and an intermetallic compound density of 35000 pieces / mm ² or more, the uniformity of the electrolytically roughened surface becomes better.

As described above, from the viewpoint of suppressing minute corrosion stains, it is preferable that the number of intermetallic compounds having an equivalent circle diameter of more than 1 μm existing on the surface of the aluminum alloy plate is small. Specifically, the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface of the aluminum alloy plate is preferably 2500 / mm ² or less, and more preferably 1500 / mm ² or less. .

Here, the number and density of intermetallic compounds on the surface of the aluminum alloy plate can be measured by the following method.
First, an aluminum alloy plate obtained by wiping off the oil on its surface with acetone is used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate is taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Subsequently, five images arbitrarily selected from the obtained reflected electron images are stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. Specify the equivalent circle diameter (equivalent circle diameter) to obtain the particle size distribution.
From the result of the particle size distribution, the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more is calculated. This calculation is performed by rounding off the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.
In addition, the number of intermetallic compounds having an equivalent circle diameter of 1 μm or more is calculated in the same procedure.
The density of the intermetallic compound on the surface of the aluminum alloy plate or the number of intermetallic compounds is the same on the back surface of the aluminum alloy plate on which the image recording layer is not formed after the lithographic printing plate precursor is produced. Can be measured.

The intermetallic compound present in the aluminum alloy plate varies depending on the type of metal element contained in the aluminum alloy plate, but in the case of a preferred embodiment of the aluminum alloy plate described later, which contains Al, Si and Fe as essential components, the aluminum alloy plate Specifically, examples of the intermetallic compound present in Al include an Al—Fe intermetallic compound such as Al ₃ Fe and Al ₆ Fe and an AlFeSi intermetallic compound such as α-AlFeSi and β-AlFeSi. .
The aluminum alloy plate used in the present invention has an Al content of 99% by mass or more, and as trace elements, Si, Fe, Ni, Mn, Cu, Mg, Cr, Zn, Bi, Ti, and V are used. It contains at least one element selected from the group consisting of:
The aluminum alloy plate used in the present invention is preferably a preferred embodiment of an aluminum alloy plate to be described later, which contains Al, Si and Fe as essential components.

As described above, in the preferred embodiment of the aluminum alloy plate containing Al, Si, and Fe as essential components, the aluminum alloy plate includes an Al—Fe-based intermetallic compound such as Al ₃ Fe, Al ₆ Fe, or α- AlFeSi-based intermetallic compounds such as AlFeSi and β-AlFeSi, or both exist.
Among these, Al-Fe-based intermetallic compounds have been found to be a starting point for corrosion of aluminum alloy sheets when many hydrophilic components are contained in the image recording layer. From the viewpoint, it is preferable that the amount of the Al—Fe intermetallic compound contained in the aluminum alloy plate is small. Specifically, the peak count value of the Al—Fe-based intermetallic compound of the aluminum alloy plate measured using an X-ray diffractometer (XRD) is preferably 400 cps or less, and in particular, Al ₃ Fe and Al It is preferable that both ₆ Fe have a peak count value of 400 cps or less.
Here, the peak count value of the Al—Fe-based intermetallic compound means that an aluminum alloy plate is set in an X-ray diffractometer (for example, RAD-rR (12 kW rotating counter cathode type, manufactured by Rigaku Corporation)) It was measured by.
・ Set tube voltage 50kV
・ Set tube current 200mA
・ Sampling interval 0.01 °
・ Scanning speed 1 ° / min ・ 2θ scanning range 10 ° ～ 70 °
Use of graphite monochromator From the viewpoint of suppressing minute corrosion stains, it is preferable that the peak count value of the Al—Fe intermetallic compound of the aluminum alloy plate is 200 cps or less, particularly both Al ₃ Fe and Al ₆ Fe. The peak count value is preferably 200 cps or less.

On the other hand, it has been found that Al—Fe—Si intermetallic compounds such as α-AlFeSi and β-AlFeSi are less likely to be a starting point of corrosion of an aluminum alloy plate than Al—Fe intermetallic compounds.
Among these, Al-Fe-based intermetallic compounds have been found to be a starting point for corrosion of aluminum alloy sheets when many hydrophilic components are contained in the image recording layer. From the viewpoint, it is preferable that the amount of the Al—Fe—Si intermetallic compound (particularly α-AlFeSi) contained in the aluminum alloy plate is large. Specifically, the peak count value of the Al—Fe—Si intermetallic compound (particularly α-AlFeSi) of the aluminum alloy plate measured using an X-ray diffractometer (XRD) is 30 cps or more. Preferably, it is 50 cps or more.

<Aluminum alloy plate (rolled aluminum)>
Hereinafter, the suitable aspect of the aluminum alloy plate used for this invention is described.
The preferred embodiment of the aluminum alloy plate used in the present invention is that the Al content is 99% by mass or more, 0.03 to 0.20% by mass of Si, and 0.11 to 0.45% by mass of Fe. The solid solution amount of Si is 120 to 600 ppm, and the solid solution amount of Fe is 100 ppm or less.
By using the preferred embodiment of the aluminum alloy plate described above, the stability of the electrolytic surface roughening treatment can be improved, and the uniformity of the electrolytic surface roughened surface can be enhanced. As a result, a support having a uniform electrolytic roughened surface can be obtained even under various electrolytic roughening treatment conditions. By using the support, lithographic printing excellent in printing durability and stain resistance is obtained. You can get the original version.
Although the essential alloy component in the suitable aspect of the aluminum alloy plate mentioned above is Al, Fe, and Si, you may contain copper (Cu) as an arbitrary component.

  Si is an element contained as an inevitable impurity in an Al ingot, which is a raw material, in an amount of about 0.03 to 0.1% by mass, and is often intentionally added in a small amount to prevent variation due to a difference in raw materials. Si exists as a solid solution in aluminum, or as an intermetallic compound or a single precipitate.

In the present invention, the Si content is preferably 0.03 to 0.20 mass%, more preferably 0.04 to 0.18 mass%, and 0.05 to 0.15 mass%. More preferably.
When the Si content is within this range, the necessary amount of Si solid solution is ensured, and even when the anodizing treatment is performed after the electrolytic surface-roughening treatment, it is difficult for defects to occur in the anodized film. Thus, the stain resistance as a lithographic printing plate is also improved.

Moreover, in this invention, it is preferable that the solid solution amount of Si is 120-600 ppm, It is more preferable that it is 150-600 ppm, It is further more preferable that it is 150-500 ppm.
When the solid solution amount of Si is within this range, the electrolytic roughened surface becomes uniform, and pits having average opening diameters of 0.01 to 0.05 μm and 0.05 to 1.5 μm are uniform over the entire surface. Formed.

  Fe is an element that hardly dissolves in aluminum and remains as an intermetallic compound.

In the present invention, the Fe content is preferably 0.11 to 0.45 mass%, more preferably 0.15 to 0.45 mass%, and 0.20 to 0.43 mass%. More preferably.
When the Fe content is within this range, Fe is dispersed as a fine intermetallic compound, and as a result of acting as a starting point for the electrolytic roughening treatment, the electrolytic roughened surface becomes uniform.

In the present invention, from the viewpoint of securing a necessary intermetallic compound of Fe, the solid solution amount of Fe is preferably 100 ppm or less, more preferably 50 ppm or less, and further 40 ppm or less. preferable.
From the viewpoint of ensuring the heat resistance of the aluminum alloy plate, the solid solution amount of Fe is preferably 10 ppm or more.

Cu is an important element in controlling the electrolytic surface roughening treatment, but is an optional element in the present invention.
In the present invention, from the viewpoint of maintaining the uniformity of electrolytic surface roughening, the content when Cu is contained is preferably 0.030% by mass or less.

  Since the grain refinement element does not affect the uniformity of the electrolytic surface roughening, it may be added as appropriate to prevent cracking during casting. Therefore, for example, Ti can be added in a range of 0.05% by mass or less, and B can be added in a range of 0.02% by mass or less.

The balance of the aluminum alloy plate is made of Al and inevitable impurities.
As this inevitable impurity, Mg, Mn, Zn, Cr, Zr, V, Zn, Be etc. are mentioned, for example, These may each be contained 0.05 mass% or less.
Moreover, most of inevitable impurities are contained in the Al ingot. For example, if the inevitable impurities are contained in a metal having an Al purity of 99.5%, the effects of the present invention are not impaired.
For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.

The preferred embodiment of the aluminum alloy plate described above is preferably manufactured by a continuous casting method.
Rolling by continuous casting has a high solidification rate on the surface of the cast material, so that the crystallized material is fine and uniform, does not require the homogenization heat treatment of the ingot required by the DC casting method, and is not subjected to long-time processing. Therefore, it is suitable as a base plate for a lithographic printing plate support.

Specifically, the following method is preferably exemplified.
First, a molten aluminum alloy adjusted to a predetermined alloy component content can be subjected to a cleaning treatment as necessary according to a conventional method.
Examples of the cleaning treatment include degassing treatment for removing unnecessary gases such as hydrogen in the molten metal (eg flux treatment using argon gas, chlorine gas, etc.); ceramic tube filter, ceramic foam filter, etc. A filtering process using a so-called rigid media filter, a filter using alumina flakes, alumina balls, or the like as a filter medium, a glass cloth filter, or the like; a process in which such a degassing process and a filtering process are combined;

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The present applicant has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, continuous casting is performed using a molten metal that has been subjected to a cleaning treatment as necessary.
Continuous casting is a process in which a molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. Method), a method using a cooling roll represented by the 3C method, a double belt method (Hasley method), a method using a cooling belt or a cooling block represented by the Al-Swiss Caster II type, and the like.
Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Moreover, it solidifies in the range whose cooling rate is 100-1000 degrees C / sec.
Regarding the continuous casting method, the techniques proposed by the present applicant are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

In continuous casting, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly continuously cast, and the hot rolling step can be omitted. Benefits are gained.
In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.
In the present invention, from the viewpoint of producing a large number of intermetallic compounds, a method using a cooling roll is preferred, and the plate thickness is preferably 7 mm or less.

  After the continuous casting, the obtained aluminum alloy plate is finished to a predetermined thickness, for example, a thickness of 0.1 to 0.5 mm, through a cold rolling process or the like applied as necessary.

In the present invention, intermediate annealing treatment may be performed from the viewpoint of increasing the Si solid solution amount or suppressing the Fe solid solution amount before, after, or during the cold rolling. Further, the appropriate intermediate annealing treatment has an effect of making the crystal grains fine, and the surface quality can be improved.
From the viewpoint of optimizing the size and number of intermetallic compounds, it is desirable to avoid the intermediate annealing treatment from being performed at an excessively high temperature or excessively for a long time. In particular, it is desirable to avoid heat treatment exceeding 550 ° C. or heat treatment exceeding 36 hours. This is because the intermetallic compound re-dissolves in aluminum, or the number decreases in the process in which the metastable phase intermetallic compound such as α-AlFeSi and β-AlFeSi changes to stable phase Al ₃ Fe. It is because there is a case to do.
As a suitable condition for the intermediate annealing treatment, a batch annealing furnace is used at 280 to 550 ° C. for 2 to 20 hours, preferably 350 to 550 ° C. for 2 to 10 hours, more preferably 350 to 550 ° C. for 2 to 5 hours. Conditions for heating for a period of time; conditions for heating at 400 to 550 ° C. for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less using a continuous annealing furnace;

The flatness of the aluminum alloy plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum alloy plate is cut into a sheet shape, but in order to improve productivity, it is preferably performed in a continuous coil state.
Further, a slitter line may be used for processing into a predetermined plate width.
Furthermore, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum alloy plates, you may provide a thin oil film on the surface of an aluminum alloy plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

<Roughening treatment>
The lithographic printing of the present invention is carried out by subjecting the surface of the aluminum alloy plate obtained through the above-described continuous casting process and various processes (for example, intermediate annealing process, cold rolling process, etc.) to be performed as desired. A support used for the plate precursor can be prepared.
As the roughening treatment, generally one or a combination of two or more of mechanical roughening treatment, chemical roughening treatment and electrochemical roughening treatment is used.
In the present invention, as the surface roughening treatment, it is preferable to perform at least electrolytic surface roughening treatment and to perform alkali etching treatment (first alkali etching treatment) before the electrolytic surface roughening treatment. It is preferable to perform an alkali etching process (second alkali etching process) later.

As the surface roughening treatment, electrochemical surface roughening treatment is preferably performed twice, and an etching treatment in an alkaline aqueous solution is preferably performed between them. 1 alkali etching treatment), desmut treatment in acidic aqueous solution (first desmut treatment), electrochemical roughening treatment in aqueous solution containing nitric acid or hydrochloric acid (first electrolytic roughening treatment), in alkaline aqueous solution Etching treatment (second alkali etching treatment), desmutting treatment in acidic aqueous solution (second desmutting treatment), electrochemical surface roughening treatment in aqueous solution containing hydrochloric acid (second electrolytic surface roughening treatment) Etching treatment in alkaline aqueous solution (third alkaline etching treatment), desmutting treatment in acidic aqueous solution (third desmutting treatment), and anodizing treatment in this order Be treated are preferably exemplified.
Moreover, it is preferable to perform a mechanical surface-roughening process before the said alkali etching process (1st alkali etching process).
Furthermore, it is also preferable to perform sealing treatment and hydrophilization treatment after the anodizing treatment.

When manufacturing the support body used for the lithographic printing plate precursor according to the invention, various processes other than those described above may be included.
Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
In this invention, it is preferable to perform the mechanical roughening process performed in order to make the center average surface roughness of the surface of an aluminum alloy plate 0.35-1.0 micrometer.
Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.

The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is performed by rubbing one or both of the surfaces of the aluminum alloy plate while spraying a slurry liquid containing an abrasive on a rotating roller brush.
Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.

When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.
In the present invention, it is preferable to use a plurality of nylon brushes, specifically, 3 or more are more preferable, and 4 or more are particularly preferable. By adjusting the number of brushes, the wavelength component of the recess formed on the aluminum alloy plate surface can be adjusted.

  Further, the load of the drive motor that rotates the brush is preferably 1 kW plus or more, more preferably 2 kW plus or more, and particularly preferably 8 kW plus or more with respect to the load before the brush roller is pressed against the aluminum alloy plate. By adjusting the load, the depth of the recess formed on the surface of the aluminum alloy plate can be adjusted. The number of rotations of the brush is preferably 100 or more, and particularly preferably 200 or more.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumice stone (pumice stone), silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. Quartz sand is harder and less fragile than Pamiston, so it has excellent roughening efficiency. In addition, aluminum hydroxide is suitable when an excessive load is applied and the particles are damaged, so that it is not desired to generate deep recesses locally.
The median diameter of the abrasive is preferably from 2 to 100 μm, more preferably from 20 to 60 μm, from the viewpoint of excellent surface roughening efficiency and the ability to narrow the graining pitch. By adjusting the median diameter of the abrasive, the depth of the recess formed on the aluminum alloy plate surface can be adjusted.

For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.
As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.

  As for details of an apparatus for performing a mechanical surface roughening process using a brush and an abrasive, those described in JP-A-2002-2111159 can be used by the present applicant.

  Examples of the mechanical surface roughening process other than the brush grain method include a process of forming irregularities on the surface by transfer at the end of the cold rolling described above. In the present invention, instead of the brush grain method, or a brush Can be applied together with the grain method.

<First alkali etching treatment>
The first alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum alloy plate into contact with an alkali solution.

The first alkali etching treatment performed before the electrolytic surface roughening treatment (first electrolytic surface roughening treatment) is to smooth the uneven shape when the mechanical surface roughening is performed. When forming a uniform recess by the treatment (first electrolytic surface roughening treatment) and when mechanical surface roughening is not performed, the rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum alloy plate are removed. It is done for the purpose of doing.
In the first alkali etching treatment, the etching amount is preferably 0.1 g / m ² or more, more preferably 0.5 g / m ² or more, and further preferably 1 g / m ² or more. Further, it is preferably 12 g / m ² or less, more preferably 10 g / m ² or less, and still more preferably 8 g / m ² or less. When the lower limit of the etching amount is within the above range, uniform pits can be generated in the electrolytic surface roughening treatment (first electrolytic surface roughening treatment), and further, the occurrence of processing unevenness can be prevented. When the upper limit of the etching amount is in the above range, the amount of the alkaline aqueous solution used is reduced, which is economically advantageous.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of the alkali metal salt include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, primary sodium phosphate, primary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

In the first alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the first alkali etching treatment, the temperature of the alkali solution is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, and 75 ° C. or lower. Is more preferable.
In the first alkaline etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 15 seconds or shorter. preferable.

When the aluminum alloy plate is continuously etched, the aluminum ion concentration in the alkaline solution increases and the etching amount of the aluminum alloy plate varies. Therefore, the composition management of the etching solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic velocity, and temperature, corresponding to the matrix of caustic soda concentration and aluminum ion concentration, is prepared in advance, and the conductivity and specific gravity. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and caustic soda and water are added so that the control target value of the liquid composition is reached. Then, the amount of the etching liquid increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the liquid amount constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature compensated. As the specific gravity meter, a differential pressure type is preferably used.

  Examples of the method of bringing the aluminum alloy plate into contact with the alkaline solution include, for example, a method of passing the aluminum alloy plate through a tank containing an alkaline solution, a method of immersing the aluminum alloy plate in a tank containing an alkaline solution, and an alkali. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.

  Among these, a method of spraying an alkaline solution onto the surface of the aluminum alloy plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the alkali etching process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds and then drain the liquid with a nip roller.
The water washing treatment is preferably carried out using an apparatus for washing with a free-falling curtain-like liquid film, and further using a spray tube.

The apparatus for washing with a free-fall curtain liquid film is a water storage tank for storing water, a water supply pipe for supplying water to the water storage tank, and a free-fall curtain liquid film from the water storage tank to the aluminum alloy plate. And a rectifying unit.
In this apparatus, water is supplied to the water supply tank from the water supply cylinder, and when the water overflows from the water supply tank, the water is rectified by the rectifying unit, and a free-falling curtain-like liquid film is supplied to the aluminum alloy plate. When this apparatus is used, the liquid amount is preferably 10 to 100 L / min. Moreover, it is preferable that the distance L in which water exists as a free fall curtain-like liquid film between a rectification | straightening part and aluminum is 20-50 mm. Moreover, it is preferable that the angle (alpha) of an aluminum alloy plate is 30-80 degrees with respect to a horizontal direction.

  If an apparatus for performing water washing treatment with a free-fall curtain-like liquid film is used, the aluminum alloy plate can be uniformly washed with water, so that the uniformity of the treatment performed before the water washing treatment can be improved. As a specific apparatus for washing with a free-fall curtain-like liquid film, for example, an apparatus described in JP-A-2003-96584 is preferably exemplified.

  Moreover, as a spray tube used for the water washing process, for example, a spray tube having a plurality of spray tips spreading in a fan shape in the width direction of the aluminum alloy plate can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 0.5 to 20 L / min. It is preferable to use a plurality of spray tubes.

<First desmut treatment>
After the first alkali etching treatment, it is preferable to perform pickling (first desmutting treatment) in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing the aluminum alloy plate into contact with an acidic solution.

Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
In the first desmutting process performed after the first alkali etching process, when nitric acid electrolysis is continuously performed as the electrolytic surface roughening process (first electrolytic surface roughening process), an electrolytic solution used for nitric acid electrolysis is used. It is preferable to use an overflow waste liquid.

In the composition management of the desmut treatment liquid, a method of managing by conductivity and temperature, a method of managing by conductivity, specific gravity and temperature, and a conductivity and superconductivity corresponding to a matrix of acidic solution concentration and aluminum ion concentration. Either of the methods managed by the propagation speed of sound waves and temperature can be selected and used.
In the first desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 5 g / L aluminum ions.

  The temperature of the acidic solution is preferably 20 ° C. or more, more preferably 30 ° C. or more, and preferably 70 ° C. or less, more preferably 60 ° C. or less.

  In the first desmutting treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 40 seconds or shorter. .

Examples of the method of bringing an aluminum alloy plate into contact with an acidic solution include a method of passing an aluminum alloy plate through a tank containing an acidic solution, a method of immersing an aluminum alloy plate in a tank containing an acidic solution, and an acidic solution. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.
Among these, a method in which an acidic solution is sprayed on the surface of the aluminum alloy plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.
In the first desmut process, when using an overflow waste liquid of the electrolyte used for the subsequent nitric acid electrolysis as the desmut process liquid, after the desmut process, the draining with a nip roller and the water washing process are not performed. It is preferable to handle the aluminum alloy plate until the nitric acid electrolysis step while spraying a desmut treatment liquid as necessary so that the surface does not dry.

<First electrolytic surface roughening treatment>
The first electrolytic surface roughening treatment is an electrolytic surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid.
In the present invention, the first electrolytic surface roughening treatment is preferably a treatment using a trapezoidal waveform alternating current in an electrolytic solution containing nitric acid because the latitude of the electrolytic surface roughened surface is increased. It is preferable to use a sinusoidal alternating current in the electrolyte solution containing selenium because it is easy to control the surface shape of the electrolytically roughened surface.
The average roughness R _a of the aluminum alloy plate surface of the first electrolytic graining treatment is preferably 0.2 to 1.0 [mu] m.

(Electrolytic roughening treatment in aqueous solution containing nitric acid (nitric acid electrolysis))
A suitable uneven structure can be formed on the surface of the aluminum alloy plate by nitric acid electrolysis. In the present invention, when the aluminum alloy plate contains a relatively large amount of Cu, a relatively large and uniform recess is formed in nitric acid electrolysis. As a result, the lithographic printing plate using the lithographic printing plate support of the present invention has excellent printing durability.

The aqueous solution containing nitric acid can be one used for electrochemical surface roughening using ordinary direct current or alternating current, and an aqueous solution of nitric acid having a concentration of 1 to 100 g / L can be used for aluminum nitrate, sodium nitrate, ammonium nitrate, etc. At least one of the nitrate compounds having the nitrate ion can be added and used in the range from 1 g / L to saturation.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing nitric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L.
Specifically, a solution prepared by dissolving aluminum nitrate in an aqueous nitric acid solution having a nitric acid concentration of 5 to 15 g / L and adjusting the aluminum ion concentration to 3 to 7 g / L is preferable.

  The temperature of the aqueous solution containing nitric acid is preferably 20 ° C. or higher, and preferably 55 ° C. or lower.

  Pits having an average opening diameter of 1 to 10 μm can be formed by nitric acid electrolysis. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 10 μm are also generated.

In order to obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum alloy plate up until the electrolysis reaction is completed is preferably at 150C / dm ² or more, 170C / dm ² or more more preferably is, but preferably not 600C / dm ² or less, more preferably 500C / dm ² or less.
The current density at this time is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² in terms of current peak value.

(Electrolytic roughening treatment in aqueous solution containing hydrochloric acid (hydrochloric acid electrolysis))
As the aqueous solution containing hydrochloric acid, those used for electrochemical surface roughening treatment using ordinary direct current or alternating current can be used. One or more of hydrochloric acid or nitric acid compounds having nitrate ions such as sodium nitrate and ammonium nitrate, and hydrochloric acid ions such as aluminum chloride, sodium chloride and ammonium chloride can be added to 1 g / L to saturation.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, and a silica, may melt | dissolve in the aqueous solution containing hydrochloric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L. Furthermore, the above-mentioned compound which forms a complex with copper can also be added at a rate of 1 to 200 g / L. Moreover, sulfuric acid can also be added at a rate of 1 to 100 g / L.

Furthermore, the aqueous solution containing hydrochloric acid has an aluminum ion concentration of 3 to 7 g / L, preferably by adding an aluminum salt (aluminum chloride, AlCl ₃ .6H ₂ O) to an aqueous solution containing 2 to 10 g / L of hydrochloric acid. Particularly preferred is an aqueous solution of 4 to 6 g / L.
When electrolytic surface roughening is performed using such an aqueous hydrochloric acid solution, the surface roughened electrolytic surface becomes more uniform, and even if a low purity aluminum alloy plate is used, a high purity aluminum alloy plate is used. Even in this case, processing unevenness does not occur, and it is possible to achieve both excellent printing durability and stain resistance when using a planographic printing plate.

  The temperature of the aqueous solution containing hydrochloric acid is preferably 20 ° C or higher, more preferably 30 ° C or higher, more preferably 55 ° C or lower, and even more preferably 50 ° C or lower.

  As the additive, apparatus, power source, current density, flow rate, and temperature to the aqueous solution containing hydrochloric acid, those used for known electrochemical surface roughening can be used. AC or DC is used as the power source used for electrochemical roughening, but AC is particularly preferable.

Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface by applying a slight current. The fine irregularities have an average opening diameter (pit diameter) of 0.01 to 1.5 μm and are uniformly generated on the entire surface of the aluminum alloy plate.
Further, when the amount of electricity is increased (the total amount of electricity (anode reaction) is 150 to 2000 C / dm ² ), the average opening diameter is 1 to 30 μm having pits with an average opening diameter of 0.01 to 0.4 μm on the surface. A pit is generated. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum alloy plate at the time when the electrolytic reaction is completed is preferably 10 C / dm ² or more, and more preferably 50 C / dm ² or more. Is more preferable, and more preferably 100 C / dm ² or more. But preferably not more 2000C / dm ² or less, more preferably 600C / dm ² or less.

In hydrochloric acid electrolysis, the current density is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² at the peak current value.

  When the aluminum alloy plate is subjected to hydrochloric acid electrolysis with the above-mentioned large electric quantity, large waviness and fine irregularities can be formed at the same time, and by making the large waviness more uniform by the second alkali etching process described later, the stain resistance is improved. Can be improved.

  The first electrolytic surface roughening treatment can be performed according to, for example, the electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

Various electrolyzers and power sources have been proposed, including US Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP 53-32821, JP 53-32222, JP 53-32823, JP 55-122896, JP 55-13284, JP 62-127500, JP Those described in JP-A-1-52100, JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-133638, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 And those described in JP-A No. 54-146234 and the like can also be used.

As the aluminum alloy plate is continuously subjected to electrolytic surface roughening, the aluminum ion concentration in the alkaline solution increases, and the shape of the irregularities of the aluminum alloy plate formed by the first electrolytic surface roughening treatment varies. To do. Therefore, the composition management of the nitric acid electrolytic solution or hydrochloric acid electrolytic solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature corresponding to a matrix of nitric acid concentration or hydrochloric acid concentration and aluminum ion concentration is prepared in advance. The liquid composition is measured by the degree, specific gravity and temperature, or the electric conductivity, the ultrasonic wave propagation speed and the temperature, and nitric acid or hydrochloric acid and water are added so as to reach the control target value of the liquid composition. Then, the electrolytic solution increased by adding nitric acid or hydrochloric acid and water is overflowed from the circulation tank, so that the amount of the electrolytic solution is kept constant. As nitric acid to be added, 30 to 70% by mass of industrial grade can be used. As hydrochloric acid to add, the industrial thing of 30-40 mass% can be used.

As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature compensated. As the specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measuring the liquid composition are used for measurement after being controlled at a constant temperature (eg, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave (sin wave, sine wave), a rectangular wave, a trapezoidal wave, a triangular wave, or the like is used. Waves are preferred and trapezoidal waves are particularly preferred. In the case of the first hydrochloric acid electrolysis, a sine wave is particularly preferable in that pits having an average diameter of 1 μm or more are easily generated. The sine wave refers to that shown in FIG.
A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 0.5 to 3 msec. When TP exceeds 3 msec, especially when an aqueous solution containing nitric acid is used, it becomes susceptible to the influence of trace components in the electrolytic solution typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining. Is difficult to be performed. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

An AC duty ratio of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum, a duty ratio is used. Is preferably 1: 1.
An AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is easily affected by the inductance component on the power supply circuit, and the power supply cost is increased.

FIG. 2 is a side view showing an example of a radial type cell used for electrochemical surface roughening using alternating current.
One or more AC power supplies can be connected to the electrolytic cell. For the purpose of controlling the current ratio between the alternating current anode and cathode applied to the aluminum alloy plate facing the main electrode, uniform graining, and dissolving the carbon of the main electrode are shown in FIG. Thus, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 2, 11 is an aluminum alloy plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. Yes, 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 is a main electrolytic cell, and 50 is an auxiliary anode cell. An anode acting on the aluminum alloy plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifying element or a switching element It is possible to control the ratio between the current value for the reaction and the current value for the cathode reaction. On the aluminum alloy plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.

  As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

  In addition, in the electrochemical surface roughening treatment using direct current, an electrolytic solution used for the electrochemical surface roughening treatment using normal direct current can be used. Specifically, the same electrolyte solution used for the electrochemical surface roughening treatment using the alternating current can be used.

The DC power supply wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity. Smoothed continuous direct current is preferred.
The electrochemical surface roughening treatment using direct current can be performed by any of a batch method, a semi-continuous method, and a continuous method, but is preferably performed by a continuous method.

  The apparatus used for the electrochemical surface roughening treatment using direct current applies a direct current voltage between anodes and cathodes arranged alternately, and an aluminum alloy plate is spaced from the anode and cathode. If it can be passed, it will not be specifically limited.

An electrode is not specifically limited, The conventionally well-known electrode used for an electrochemical roughening process can be used.
As the anode, for example, a valve metal such as titanium, tantalum, or niobium is plated or clad with a platinum group metal; the valve metal is coated with an oxide of a platinum group metal or sintered. Aluminium; stainless steel. Among these, a valve metal obtained by cladding platinum is preferable. The life of the anode can be further extended by a method such as water-cooling by passing water through the electrode.
As the cathode, for example, a metal that does not dissolve when the electrode potential is negative can be selected and used from the Boolean Bay diagram. Among these, carbon is preferable.

  The arrangement of the electrodes can be appropriately selected according to the wave structure. In addition, by changing the length of the aluminum alloy plate in the traveling direction between the anode and the cathode, changing the passing speed of the aluminum alloy plate, changing the flow rate of the electrolyte, the temperature, the liquid composition, the current density, etc. The structure can be adjusted. In addition, in the case of using an apparatus in which the anode tank and the cathode tank are separated from each other, the electrolysis conditions of each treatment tank can be changed.

After the first electrolytic surface roughening treatment is finished, it is preferable to drain the liquid with a nip roller, and further perform the water washing treatment for 1 to 10 seconds and then drain the liquid with a nip roller.
The washing treatment is preferably carried out using a spray tube. As a spray tube used for the water washing treatment, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum alloy plate in which spray water spreads in a fan shape can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

<Second alkali etching treatment>
The second alkaline etching process performed between the first electrolytic surface roughening process and the second electrolytic surface roughening process includes dissolving the smut generated in the first electrolytic surface roughening process, and the first electrolytic roughing process. This is performed for the purpose of dissolving the edge portion of the pit formed by the surface treatment.
As a result, the edge portion of the large pit formed by the first electrolytic surface roughening treatment is melted and the surface becomes smooth, so that the ink is not easily caught on the edge portion. Can be obtained.
Since the second alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. When the etching amount is 0.05 g / m ² or more, the edge portion of the pit generated by the first electrolytic surface roughening process becomes smooth in the non-image portion of the lithographic printing plate, and the ink is difficult to get caught. Excellent in properties. On the other hand, when the etching amount is 4 g / m ² or less, the unevenness generated by the first electrolytic surface roughening treatment becomes large, and thus the printing durability is excellent.

In the second alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

<Second desmut treatment>
After the second alkali etching treatment, it is preferable to perform pickling (second desmut treatment) in order to remove dirt (smut) remaining on the surface. The second desmut process can be performed in the same manner as the first desmut process.

In the second desmut treatment, nitric acid or sulfuric acid is preferably used.
In the second desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 8 g / L aluminum ions.
When using sulfuric acid, specifically, use a solution prepared by dissolving aluminum sulfate in an aqueous sulfuric acid solution having a sulfuric acid concentration of 100 to 350 g / L so that the aluminum ion concentration is 0.1 to 5 g / L. Can do. Moreover, the overflow waste liquid of the electrolyte solution used for the anodizing process mentioned later can also be used.

In the second desmut treatment, the treatment time is preferably 1 second or more, more preferably 4 seconds or more, and preferably 60 seconds or less, more preferably 20 seconds or less. .
In the second desmut treatment, the temperature of the acid aqueous solution is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, and preferably 60 ° C. or lower. More preferred.

<Second electrolytic surface roughening treatment (second hydrochloric acid electrolysis)>
The second electrolytic surface roughening treatment is an electrochemical surface roughening treatment using alternating current or direct current in an aqueous solution containing hydrochloric acid.
In the present invention, only the first electrolytic surface roughening treatment described above may be used, but by combining this second electrolytic surface roughening treatment, a more complicated uneven structure can be formed on the surface of the aluminum alloy plate, As a result, the printing durability can be improved.

The second electrolytic surface roughening treatment is basically the same as the hydrochloric acid electrolysis described in the first electrolytic surface roughening treatment.
The total amount of electricity that the aluminum alloy plate takes part in the anodic reaction by electrochemical surface roughening in an aqueous solution containing hydrochloric acid in the second electrolytic surface roughening treatment is the time when the electrochemical surface roughening treatment is completed. in may be selected from the range of 10~200C / dm ^2, to first electrolytic graining increase destroying not formed was roughened by treatment is preferably ^{10~100C / dm 2, 50~80C / dm} 2 is Particularly preferred.

<First Alkaline Etching Treatment-First Electrolytic Roughening Treatment (Nitric Acid Electrolysis) -Second Alkaline Etching Treatment-Second Electrolytic Roughening Treatment (Second Hydrochloric Acid Electrolysis)>
When performing the above treatment in combination, nitric acid electrolysis in which the total amount of electricity in the anodic reaction is 65 to 500 C / dm ² in the electrolytic solution containing nitric acid, and alkaline etching in which the dissolution amount is 0.1 g / m ² or more. Treatment, second hydrochloric acid electrolysis in which the total amount of electricity in the anodic reaction is 25 to 100 C / dm ² in an electrolytic solution containing hydrochloric acid, and alkaline etching treatment in which the dissolution amount is 0.03 g / m ² or more. It is preferable to apply in order.
By roughening with this combination, a lithographic printing plate precursor having more excellent stain resistance and printing durability can be obtained.

<Third alkali etching treatment>
The third alkali etching process performed after the second electrolytic surface roughening process is performed by dissolving the smut generated by the second electrolytic surface roughening process and the edge of the pit formed by the second electrolytic surface roughening process. This is done for the purpose of dissolving the part. Since the third alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the third alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, is 0.3 g / m ² or less Of 0.25 g / m ² or less is more preferable. When the etching amount is 0.05 g / m ² or more, the edge portion of the pit generated by the second hydrochloric acid electrolysis becomes smooth in the non-image portion of the lithographic printing plate, and the ink is difficult to catch, so that the stain resistance is excellent. . On the other hand, when the etching amount is 0.3 g / m ² or less, the unevenness generated by the first electrolytic surface roughening treatment and the second electrolytic surface roughening treatment becomes large, and thus the printing durability is excellent.

In the third alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, and in order not to make the unevenness caused by the hydrochloric acid alternating current electrolysis in the previous stage too small, the concentration is 100 g / L or less. It is preferable that it is 70 g / L or less.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, and preferably 50 g / L or less, more preferably 8 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the third alkali etching treatment, the temperature of the alkaline solution is preferably 25 ° C or higher, more preferably 30 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.
In the third alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

<Third desmut treatment>
After the third alkali etching treatment, pickling (third desmutting treatment) is preferably performed to remove dirt (smut) remaining on the surface. Since the third desmut process is basically the same as the first desmut process, only the differences will be described below.
In the third desmutting treatment, it is preferable to use an acidic solution containing 5-400 g / L acid and 0.5-8 g / L aluminum ions. When sulfuric acid is used, specifically, a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L to adjust the aluminum ion concentration to 1 to 5 g / L is preferable.

In the third desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of liquid as the electrolyte used in the subsequent anodizing process is used as the desmut process liquid, the draining with a nip roller and the water washing process can be omitted after the desmut process.

<Anodizing treatment>
It is preferable to anodize the aluminum alloy plate treated as described above.
The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum alloy plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

  Under the present circumstances, the component normally contained at least in an aluminum alloy plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the second and third components may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cation such as ammonium ion; anion such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10,000 ppm It may be contained at a concentration of about.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, electrolysis time 15 seconds to 50 minutes are appropriate, and the amount of anodic oxide film is adjusted as desired.

  Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), more preferably 50 to 200 g / L (5 to 20% by mass), and the aluminum ion concentration. Is preferably 1 to 25 g / L (0.1 to 2.5% by mass), more preferably 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

  The composition management of the electrolyte is conducted using the same method as in the case of nitric acid electrolysis described above, and the conductivity, specific gravity and temperature, or conductivity and ultrasonic wave propagation corresponding to the matrix of sulfuric acid concentration and aluminum ion concentration. It is preferable to control by speed and temperature.

  The liquid temperature of the electrolytic solution is preferably 25 to 55 ° C, and more preferably 30 to 50 ° C.

When anodizing is performed in an electrolytic solution containing sulfuric acid, a direct current may be applied between the aluminum alloy plate and the counter electrode, or an alternating current may be applied.
When a direct current is applied to the aluminum alloy plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case of continuous anodizing treatment, at the beginning of anodizing treatment, so as not to cause so-called "burn" (part where the film becomes thicker than the surroundings) due to current concentration on a part of the aluminum alloy plate. It is preferable to increase the current density to 30 to 50 A / dm ² or higher as the anodic oxidation process proceeds with a current flowing at a low current density of 5 to 10 A / m ² .
Specifically, it is preferable that the current distribution of the DC power supply is set so that the current of the downstream DC power supply is equal to or greater than the current of the upstream DC power supply. By using such current distribution, so-called burning is less likely to occur, and as a result, high-speed anodization can be performed.
When the anodizing treatment is continuously performed, it is preferable that the anodization is performed by a liquid power feeding method in which power is supplied to the aluminum alloy plate through an electrolytic solution.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. it is a 800 pieces / μm ² about.

Further, as described in JP-A-2-57391, it is particularly preferable to use a phosphoric acid solution as the electrolytic solution. In the method described in JP-A-2-57391, a phosphoric acid solution is used as an electrolytic solution, a phosphoric acid concentration of 15 to 45% by mass, an electrolytic solution temperature of 20 to 70 ° C., and a current density of 2.0 ampere / minute / dm. ^The anodizing treatment is performed under the conditions of ² or more, voltage of 50 V or more, and electrolysis time of 15 seconds to 3 minutes.
By carrying out the above procedure, the average pore diameter (surface average pore diameter) in the surface layer of the anodized film is 10 to 75 nm, preferably 20 to 50 nm, and the average value of the maximum diameter inside the pore (inside the pore) An anodized film having an average value of the maximum diameter of 1.1 to 3.0 times the average pore diameter can be formed.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, while if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Further, it is preferable that the difference in the amount of the anodized film between the center portion of the aluminum alloy plate and the vicinity of the edge portion is 1 g / m ² or less.

As electrolysis apparatuses used for anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, JP-A-2001-11698, etc. Can be used.
Among these, the apparatus shown in FIG. 3 is preferably used. FIG. 3 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum alloy plate.

  In the anodizing apparatus 410 shown in FIG. 3, in order to energize the aluminum alloy plate 416 via the electrolytic solution, the feeding tank 412 is upstream of the aluminum alloy plate 416 in the traveling direction, and the anodizing tank is downstream. 414 is installed. Aluminum alloy plate 416 is conveyed by pass rollers 422 and 428 as indicated by arrows in FIG. In the power supply tank 412 into which the aluminum alloy plate 416 is first introduced, an anode 420 connected to the positive electrode of the DC power supply 434 is installed, and the aluminum alloy plate 416 serves as a cathode. Therefore, a cathode reaction occurs in the aluminum alloy plate 416.

In the anodizing tank 414 into which the aluminum alloy plate 416 is subsequently introduced, a cathode 430 connected to the negative electrode of the DC power source 434 is installed, and the aluminum alloy plate 416 serves as an anode. Therefore, an anodic reaction occurs in the aluminum alloy plate 416, and an anodized film is formed on the surface of the aluminum alloy plate 416.
The distance between the aluminum alloy plate 416 and the cathode 430 is preferably 50 to 200 mm. Aluminum is used as the cathode 430. The cathode 430 is not an electrode having a large area but an electrode divided into a plurality of pieces in the traveling direction of the aluminum alloy plate 416 so that the hydrogen gas generated by the anode reaction can easily escape from the system. preferable.

  Between the power supply tank 412 and the anodizing tank 414, it is preferable to provide a tank called an intermediate tank 413 that does not accumulate an electrolyte as shown in FIG. By providing the intermediate tank 413, it is possible to prevent the current from bypassing the anode 420 to the cathode 430 without passing through the aluminum alloy plate 416. It is preferable to reduce the bypass current as much as possible by installing a nip roller 424 in the intermediate tank 413 to drain the liquid. The electrolyte discharged by draining is discharged out of the anodizing apparatus 410 from the drain port 442.

  The electrolyte solution 418 stored in the power supply tank 412 has a higher temperature and / or higher concentration than the electrolyte solution 426 stored in the anodizing tank 414 in order to reduce voltage loss. In addition, the composition, temperature, and the like of the electrolytic solutions 418 and 426 are determined from the formation efficiency of the anodized film, the micropore shape of the anodized film, the hardness of the anodized film, the voltage, the cost of the electrolytic solution, and the like.

  Electrolyte is ejected from the liquid supply nozzles 436 and 438 and supplied to the power supply tank 412 and the anodizing treatment tank 414. For the purpose of making the distribution of the electrolyte constant and preventing local current concentration of the aluminum alloy plate 416 in the anodizing tank 414, the liquid supply nozzles 436 and 438 are provided with slits, and the ejected liquid flow is changed in the width direction. It has a structure that makes it constant.

  In the anodizing bath 414, a shielding plate 440 is provided on the opposite side of the aluminum alloy plate 416 from the anode 430, and current flows on the opposite side of the surface of the aluminum alloy plate 416 where the anodized film is to be formed. Suppresses The distance between the aluminum alloy plate 416 and the shielding plate 440 is preferably 5 to 30 mm. It is preferable to use a plurality of DC power supplies 434 and connect the positive electrode sides in common. Thereby, the current distribution in the anodizing bath 414 can be controlled.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, even if the sealing treatment is carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorinated zirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a subbing layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids.
Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

  Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. It is preferable to carry out the treatment.

Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures.
Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of Group 4 (Group IVA) metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² .
By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.

The hydrophilization treatment by forming a hydrophilic undercoat layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491.
Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, sulfo group-containing vinyl polymerizable compounds such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Examples of hydrophilic compounds that may be used in this method include, -NH ₂ group, compounds having at least one selected from the group consisting of -COOH group and sulfo group.

<Dry>
After obtaining the support used for the lithographic printing plate precursor according to the present invention by the procedure described above, it is preferable to dry the surface of the support before providing the image recording layer on the support. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 20 seconds or shorter, and even more preferably 15 seconds.

<Management of liquid composition>
In the present invention, it is preferable to manage the composition of various processing solutions used for the surface treatment described above by the method described in JP-A-2001-121837. Prepare a large number of treatment liquid samples of various concentrations in advance, measure the ultrasonic wave propagation speed at each of the two liquid temperatures, create a matrix-like data table, It is preferable to measure the propagation speed of the light in real time and control the concentration based on the measurement. In particular, in the desmutting treatment, when an electrolytic solution having a sulfuric acid concentration of 250 g / L or more is used, it is preferable to control the concentration by the method described above.
In addition, it is preferable that each electrolyte solution used for an electrolytic roughening process and an anodic oxidation process is 100 ppm or less of Cu concentration. If the Cu concentration is too high, Cu is deposited on the aluminum alloy plate when the line is stopped, and Cu deposited when the line is operated again may be transferred to a pass roll, which may cause processing unevenness.

[Image recording layer]
An image recording layer is formed on the support prepared by the procedure described above. As described above, the image recording layer of the lithographic printing plate precursor according to the invention has (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a polymer. .

(A) Sensitizing dye A sensitizing dye absorbs light at the time of image exposure to be in an excited state, and supplies energy to the polymerization initiator described later by electron transfer, energy transfer, or heat generation, thereby improving the polymerization initiation function. Any material can be used without particular limitation. In particular, a sensitizing dye having a maximum absorption at 300 to 450 nm or 760 to 1200 nm is preferably used.

  Examples of the sensitizing dye having the maximum absorption in the wavelength range of 350 to 450 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, and anthracenes. As specific examples of such sensitizing dyes, compounds described in JP-A 2007-58170 [0047] to [0053] are preferably used. Further, there are also sensitizing dyes described in JP2007-171406, JP2007-206216, JP2007-206217, JP2007-225701, JP2007-225702, JP2007-316582, and JP2007-328243. It can be preferably used.

(A-1) Infrared absorbing dye Among the sensitizing dyes, a sensitizing dye having a maximum absorption at 760 to 1200 nm is preferably used. These are called infrared absorbing pigments, and in particular, an infrared absorbing dye which is a dye having an absorption maximum at a wavelength of 760 to 1200 nm is preferably used.

As the infrared absorbing dye, compounds described in paragraph numbers [0058] to [0087] of JP-A-2008-195018 can be used.
Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen ^{atom, -N (R 9) (R} 10), - X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different, and may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. Represents a hydrogen atom, and R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred. X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. . In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom .

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxy groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and charge neutralization is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used in the present invention include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and JP-A No. 2002-023360. Examples thereof include those described in paragraph Nos. [0012] to [0021] of Japanese Patent Publication No. and paragraph Nos. [0012] to [0037] of JP-A No. 2002-040638.

  Moreover, only 1 type may be used for these infrared absorption dyes, and 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, compounds described in JP 2008-195018 A [0072] to [0076] are preferable.

  In the present invention, the content of the sensitizing dye in the image recording layer is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 5.0% by mass, based on the total solid content of the image recording layer. .

(B) Polymerization initiator The polymerization initiator used in the present invention is a compound that initiates and accelerates the polymerization of a polymerizable compound. As the polymerization initiator that can be used in the present invention, a radical polymerization initiator is preferable, and a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used.
Examples of the radical polymerization initiator in the present invention include (a) an organic halide, (b) a carbonyl compound, (c) an azo compound, (d) an organic peroxide, (e) a metallocene compound, and (f) an azide compound. (G) hexaarylbiimidazole compound, (h) organic borate compound, (i) disulfone compound, (j) oxime ester compound, (k) onium salt compound.

  (A) As the organic halide, compounds described in paragraph numbers [0022] to [0023] of JP-A-2008-195018 are preferable.

  (B) As the carbonyl compound, compounds described in paragraph [0024] of JP-A-2008-195018 are preferable.

  (C) As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  (D) As the organic peroxide, for example, compounds described in paragraph [0025] of JP-A-2008-195018 are preferable.

  As the (e) metallocene compound, for example, the compound described in paragraph [0026] of JP-A-2008-195018 is preferable.

(F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As the hexaarylbiimidazole compound, for example, a compound described in paragraph [0027] of JP-A-2008-195018 is preferable.

  (H) As the organic borate compound, for example, a compound described in paragraph [0028] of JP-A-2008-195018 is preferable.

  (I) Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  (J) As the oxime ester compound, for example, compounds described in paragraph numbers [0028] to [0030] of JP-A-2008-195018 are preferable.

  (K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, U.S. Pat. Nos. 339,049, 410,201, U.S. Patent Application Publication No. 2008 No. 0311520, iodonium salts described in JP-A-2-150848, JP-A-2-296514, JP-A-2008-195018, European Patent Nos. 370,693 and 390,214. 233,567, 297,443, 297,442, U.S. Pat.Nos. 4,933,377, 161,811 410,201, 339,049, 4,760,013, 4,734,444, 2,833,827, German Patent 2,904,626, 3 , 604, 580, and 3,604, 581, the sulfonium salts described in the respective specifications; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as azinium salts described in JP-A-2008-195018.

  Of these, more preferred are onium salts, especially iodonium salts, sulfonium salts and azinium salts. Although the specific example of these compounds is shown below, it is not limited to this.

  As an example of the iodonium salt, a diphenyl iodonium salt is preferable, and a diphenyl iodonium salt substituted with an electron donating group such as an alkyl group or an alkoxyl group is particularly preferable, and an asymmetric diphenyl iodonium salt is more preferable. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium = hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium = hexa. Fluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxy Phenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis ( -t- butylphenyl) iodonium tetraphenylborate and the like.

  Examples of sulfonium salts include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium = Examples include tetrafluoroborate and tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate.

  Examples of azinium salts include 1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1-cyclohexyl (2-ethylhexyloxy) -4-phenylpyridinium = hexafluorophosphate, 4-chloro-1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-ethoxy-4-cyanopyridinium = hexafluorophosphate, 3,4 -Dichloro-1- (2-ethylhexyloxy) pyridinium = hexafluorophosphate, 1-benzyloxy-4-phenylpyridinium = hexafluorophosphate, 1-phenethylo Ci-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = p-toluenesulfonate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = perfluorobutanesulfonate 1- (2-ethylhexyloxy) -4-phenylpyridinium bromide, 1- (2-ethylhexyloxy) -4-phenylpyridinium tetrafluoroborate.

  The polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the image recording layer. Can be added. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained.

(C) Polymerizable compound The polymerizable compound that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond, preferably It is preferably selected from compounds having two or more. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and their (co) polymers.

  Specific examples include the compounds described in JP-A-2008-105018, paragraph numbers [0089] to [0098]. Among them, preferred are esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and the like). Another preferred radically polymerizable compound is a polymerizable compound having an isocyanuric acid structure described in JP-A-2005-329708.

  Among them, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, etc. are excellent in the balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide modified acrylates are particularly preferred.

  In the present invention, the polymerizable compound is used in an amount of preferably 5 to 80% by mass, more preferably 25 to 75% by mass, based on the total solid content of the image recording layer.

(D) Polymer The image recording layer of the present invention contains a polymer in order to impart on-press developability. In particular, a polymer having a polyalkylene oxide chain (EO chain) is preferable. A polymer having a polyalkylene oxide chain, particularly a polymer having a polyalkylene oxide chain in the side chain, does not have a specific shape such as a particle shape even if it is contained in the form of fine particles in the image recording layer, and image recording It may be contained as a medium for compatibilizing or bonding various materials in the layer (hereinafter referred to as a binder polymer in the present invention). In any case, by introducing a polyalkylene oxide chain into such a polymer, the permeability of the fountain solution is improved and the on-press developability is improved. In particular, the alkylene oxide chain is an ethylene oxide chain, and the number of repeating units of the ethylene oxide chain is preferably 9 to 250, and particularly preferably 9 to 50.

(D-1) Polymer fine particles In the present invention, in order to improve the on-press developability, a particulate polymer, that is, polymer fine particles can be used. The polymer fine particles in the present invention are preferably at least one fine particle selected from hydrophobic thermoplastic polymer fine particles, heat-reactive polymer fine particles, microcapsules enclosing a hydrophobic compound, and crosslinked polymer fine particles (microgel).

  In the present invention, the polymer fine particles preferably have a polyalkylene oxide chain. This polyalkylene oxide chain interacts with the polyalkylene oxide group of the specific copolymer in the fountain solution, and the on-press developability is improved. In particular, the alkylene oxide chain is an ethylene oxide chain, and the number of repeating units of the ethylene oxide chain is preferably 9 to 250, and particularly preferably 9 to 50.

  The introduction of polyalkylene oxide chains into polymer fine particles is, for example, in the case of hydrophobic thermoplastic polymer fine particles or heat-reactive polymer fine particles, for example, emulsion polymerization or suspension polymerization of vinyl monomers or acrylic monomers having polyalkylene oxide chains. There is a way. In this case, as a monomer to be copolymerized, specific examples of polymers constituting such polymer fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride. , Acrylonitrile, vinyl carbazole, homopolymers or copolymers of monomers such as acrylates or methacrylates with polyalkylene oxide chains or mixtures thereof. Among them, more preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.

Hydrophobic thermoplastic polymer fine particles refer to Research Disclosure No. 1 of January 1992. 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and European Patent No. 931647, etc. It means fine particles that become hydrophobized by fusing with heat generated during the process.
The heat-reactive polymer fine particles include polymer fine particles having a heat-reactive group, and these mean fine particles that form a hydrophobized region by crosslinking due to a thermal reaction and a functional group change at that time.
The thermally reactive group in the polymer fine particle having a thermally reactive group used in the present invention may be any functional group that undergoes a reaction as long as a chemical bond is formed. Group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable group (for example, vinyl group, vinyloxy group, etc.), isocyanate group that performs addition reaction or its block, epoxy group, vinyloxy group And a functional group having an active hydrogen atom as a reaction partner (for example, an amino group, a hydroxy group, a carboxy group, etc.), a carboxy group for performing a condensation reaction, a hydroxy group or an amino group as a reaction partner, a ring-opening addition reaction Examples of suitable acid anhydrides and reaction partners are amino groups or hydroxy groups. .

In the case of microcapsules or microgels, introduction of polyalkylene oxide chains into polymer fine particles is a known method such as a method of adding polyalkylene oxide monoalkyl ether to a component of interfacial polymerization using polyfunctional isocyanate, This can be done as an application of the following description regarding polymer fine particles.
As the microcapsules used in the present invention, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or part of the constituent components of the image recording layer are encapsulated in the microcapsules. Is. The constituent components of the image recording layer can also be contained outside the microcapsules. Furthermore, it is preferable that the image recording layer containing the microcapsule includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the components of the image recording layer in and / or on the surface thereof. In particular, the microgel has a reactive microgel by having (C) a polymerizable compound on the surface thereof. From the viewpoint of image formation sensitivity and printing durability, it is particularly preferable.

  As a method for microencapsulating or microgelling the constituent components of the image recording layer, known methods can be applied.

  The average particle size of the polymer fine particles is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

  The content of the polymer fine particles is preferably in the range of 5 to 90% by mass of the total solid content of the image recording layer.

(D-2) Binder polymer In the image recording layer of the present invention, a binder polymer can be used as a binder for each component of the image recording layer and for improving the film strength. As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and polymers having film properties are preferred. Of these, acrylic resins, polyvinyl acetal resins, and polyurethane resins are preferable.
It is particularly preferable that the binder polymer has an alkylene oxide chain as a hydrophilic group from the viewpoint of improving the on-press developability. In particular, the alkylene oxide chain is an ethylene oxide chain, and the number of repeating units of the ethylene oxide chain is preferably 9 to 250, and particularly preferably 9 to 50. An acrylic resin obtained by copolymerizing an acrylic monomer having a polyalkylene oxide chain is particularly preferable.
It is considered that the alkylene oxide chain of the binder polymer interacts with the alkylene oxide group of the specific copolymer in the fountain solution used in the present invention, and the on-press developability is improved.

  In addition, in the binder polymer of the present invention, an oleophilic group such as an alkyl group, an aryl group, an aralkyl group or an alkenyl group can be introduced in order to control the inking property. Specifically, a lipophilic group-containing monomer such as an alkyl methacrylate may be copolymerized.

  Among them, as a binder polymer suitable for the present invention, as described in JP-A-2008-195018, a crosslinkable functional group for improving the film strength of the image portion is a main chain or a side chain, preferably a side chain. Have the following. Crosslinking is formed between the polymer molecules by the crosslinkable group, and curing is accelerated.

  The crosslinkable functional group is preferably an ethylenically unsaturated group such as a (meth) acryl group, a vinyl group or an allyl group, or an epoxy group, and these groups can be introduced into the polymer by polymer reaction or copolymerization. . For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

  The content of the crosslinkable group in the binder polymer is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 7.0 mmol, and most preferably 2.0 to 5.5 mmol per 1 g of the binder polymer. .

The binder polymer can further have a hydrophilic group other than the polyalkylene oxide chain. Examples of other hydrophilic groups include a hydroxy group, a carboxy group, an amino group, an ammonium group, an amide group, a sulfo group, and a phosphoric acid group. The hydrophilic group contributes to imparting on-press developability to the image recording layer. In particular, the coexistence of the crosslinkable group and the hydrophilic group makes it possible to achieve both printing durability and developability.
In order to impart a hydrophilic group to the binder polymer, a monomer having a hydrophilic group may be copolymerized.

  Specific examples (1) to (11) of the binder polymer used in the present invention are shown below, but the present invention is not limited thereto.

  The binder polymer in the present invention preferably has a mass average molar mass (Mw) of 2,000 or more, more preferably 5,000 or more, and even more preferably 10,000 to 300,000.

  In the present invention, if necessary, hydrophilic polymers such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used. Further, a lipophilic binder polymer and a hydrophilic binder polymer can be used in combination.

  The content of the binder polymer is usually 5 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the image recording layer.

(Other ingredients)
The image recording layer in the invention may further contain other components as required. Other components include hydrophobized precursors, low molecular weight hydrophilic compounds, sensitizers, surfactants, colorants, baking-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, In addition, a co-sensitizer or a chain transfer agent can be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. [0060] The compounds and addition amounts described in [0060] are preferred.

(Formation of image recording layer)
The image recording layer in the present invention is, for example, a coating solution prepared by dispersing or dissolving the necessary components in a known solvent as described in paragraphs [0142] to [0143] of JP-A-2008-195018. This is prepared by coating the substrate by a known method such as bar coater coating and drying. The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer (sometimes referred to as an intermediate layer) is preferably provided between the image recording layer and the support. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and easily peels off the image recording layer from the support in the unexposed area. Contributes to improvement. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

Specific examples of the compound used for the undercoat layer include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and JP-A-2- Examples thereof include phosphorus compounds having an ethylenic double bond reactive group described in Japanese Patent No. 304441. More preferable is a polymer resin having an adsorptive group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the surface of the support, as described in JP-A Nos. 2005-125749 and 2006-188038. It is done. The polymer resin is preferably a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group. More specifically, a phenolic hydroxyl group, a carboxyl _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - having an adsorptive group such as COCH ₂ COCH ₃ Examples thereof include a polymer resin that is a copolymer of a monomer, a monomer having a hydrophilic sulfo group, and a monomer having a polymerizable crosslinkable group such as a methacryl group or an allyl group. This polymer resin may have a crosslinkable group introduced by salt formation between a polar substituent of the polymer resin, a substituent having a counter charge and a compound having an ethylenically unsaturated bond, Other monomers, preferably hydrophilic monomers may be further copolymerized.

The content of unsaturated double bonds in the polymer resin for the undercoat layer is preferably 0.1 to 10.0 mmol, and most preferably 2.0 to 5.5 mmol, per 1 g of the polymer resin.
The polymer resin for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000.

  The undercoat layer of the present invention comprises a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability, in addition to the above-mentioned undercoat layer compound, to prevent contamination with time. Compounds having a group that interacts with the surface of an aluminum support (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil , Sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

(Oxygen barrier layer)
In the lithographic printing plate precursor according to the invention, an oxygen blocking layer may be provided on the image recording layer. The oxygen blocking layer has a function as a protective layer such as preventing the occurrence of scratches in the image recording layer and preventing ablation at the time of high-illuminance laser exposure, in addition to the function of suppressing the image formation inhibition reaction by blocking oxygen.

  The oxygen barrier layer (protective layer) having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the oxygen blocking layer, any one of a water-soluble polymer and a water-insoluble polymer can be appropriately selected and used. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.

In order to enhance oxygen barrier properties, the oxygen barrier layer preferably contains an inorganic layered compound such as natural mica and synthetic mica as described in JP-A-2005-119273.
Further, the oxygen barrier layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling surface slipperiness. Further, the oil-sensitizing agent described in the description of the image recording layer can be contained in the oxygen blocking layer.

The oxygen barrier layer is applied by a known method. The coating amount of the oxygen blocking layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / m ^2, more preferably in the range of 0.02 to 3 g / m ^2, most preferably 0 The range is 0.02 to 1 g / m ² .

[Plate making method]
The plate making of the lithographic printing plate precursor according to the invention is preferably carried out by an on-press development method. The on-press development method includes an image exposure process for a lithographic printing plate precursor, a printing process in which an oil-based ink and an aqueous component are supplied and printed without performing any development process on the exposed lithographic printing plate precursor. The unexposed portion of the planographic printing plate precursor is removed during the printing process. Imagewise exposure may be performed on the printing machine after the lithographic printing plate precursor is mounted on the printing machine, or may be separately performed with a plate setter or the like. In the latter case, the exposed lithographic printing plate precursor is mounted on a printing machine without undergoing a development process. Thereafter, by using the printing machine and supplying the oil-based ink and the aqueous component and printing as it is, an on-press development process, that is, an image recording layer in an unexposed area is removed at an early stage of printing, Accordingly, the surface of the hydrophilic support is exposed to form a non-image part. As the oil-based ink and the aqueous component, ordinary lithographic printing ink and fountain solution are used.
This will be described in more detail below.

In the present invention, the light source used for image exposure is preferably a laser. Although the laser used for this invention is not specifically limited, The solid laser and semiconductor laser etc. which irradiate infrared rays with a wavelength of 760-1200 nm are mentioned suitably.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In the laser, it is preferable to use a multi-beam laser device in order to shorten the exposure time.

  The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, image exposure is performed after a lithographic printing plate precursor is mounted on a plate cylinder of the printing press.

  When printing is performed by supplying dampening water and printing ink to the lithographic printing plate precursor exposed imagewise, the image recording layer cured by exposure has a printing ink acceptance having an oleophilic surface in the exposed portion of the image recording layer. Forming part. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion with the supplied fountain solution and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed area and printing is started.

Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink.
In this way, the planographic printing plate precursor of the present invention is developed on-press on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Manufacture of aluminum alloy sheets]
(Examples 1 to 23)
Using an aluminum alloy melt having the composition shown in Table 1 below, an aluminum alloy plate was manufactured by continuous casting with the heat treatment conditions (intermediate annealing) shown in Table 2 below.
Specifically, first, continuous casting was performed using a molten aluminum alloy of each composition so that the cast plate thickness was 5.5 mm by twin roll type continuous casting.
Next, the obtained continuous cast plate was cold-rolled to a thickness of 0.9 mm, then subjected to intermediate annealing heat treatment under the conditions shown in Table 2 below, and then cold-rolled again to obtain a 0.3 mm thickness. Finished to a thickness.
Next, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the molten aluminum alloy used for each.

(Comparative Examples 1-6)
An aluminum alloy plate was produced by DC casting using a molten aluminum alloy having the composition shown in Table 1 below.
Specifically, a 500 mm thick slab was cast by DC casting (Direct Chill) using an aluminum alloy melt of Al-5.
Subsequently, both sides of the obtained slab were faced by 20 mm, and the heat treatment in the slab state was carried out at 500 to 600 ° C. by soaking.
Next, hot rolling was performed to a thickness of 3 mm, an intermediate annealing treatment was performed at 410 to 550 ° C., and then a cold rolling was performed to a thickness of 0.3 mm.
Next, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the molten aluminum alloy.

The number per unit area of the intermetallic compound of each manufactured aluminum alloy plate was measured by the method shown below. The results are shown in Table 2 below.
(Number of intermetallic compounds per unit area)
First, about the manufactured aluminum alloy board, what wiped off the oil of the surface with acetone was used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate was taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Subsequently, five images arbitrarily selected from the obtained reflected electron images were stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. The particle size distribution was obtained by specifying the equivalent circle diameter (equivalent circle diameter).
From the result of the particle size distribution, the number of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more was calculated. In addition, this calculation was performed by rounding off the average value of the number calculated from each of the five image data (particle size distribution) to the hundreds.
In the same procedure, the number of intermetallic compounds having an equivalent circle diameter of 1 μm or more was calculated.

In addition, using an X-ray diffractometer, the peak count values of the Al—Fe-based intermetallic compound and α-AlFeSi of each manufactured aluminum alloy plate were measured under the following conditions. As the Al—Fe-based intermetallic compound, the peak count values of Al ₃ Fe and Al ₆ Fe are measured, and the maximum value is the “type of Al—Fe-based intermetallic compound (type of Al—Fe-based)”. As listed in Table 2. The peak angle of Al ₃ Fe is 24.1 °, the peak angle of Al ₆ Fe is 18.0 °, the peak angle of α-AlFeSi is 42.0 °, and the peak count value is This is a value obtained by measuring the diffraction intensity (cps) of the angle. The results are shown in Table 2 below.
X-ray diffractometer RAD-rR (12 kW rotating counter-cathode type, manufactured by Rigaku Corporation)
・ Set tube voltage 50kV
・ Set tube current 200mA
・ Sampling interval 0.01 °
・ Scanning speed 1 ° / min ・ 2θ scanning range 10 ° ～ 70 °
・ Use of graphite monochromator

[Manufacture of support]
Each manufactured aluminum alloy plate was subjected to the following roughening treatment to obtain a support used for a lithographic printing plate precursor.

  As the roughening treatment, the following treatments (a) to (k) were performed. In addition, the water washing process was performed between all the process steps.

(A) Mechanical roughening treatment (brush grain method)
Using an apparatus as schematically shown in FIG. 5, while rotating an aqueous suspension (specific gravity 1.12 g / cm ³ ) of an abrasive (pumice) as a polishing slurry liquid on the surface of the aluminum alloy plate, rotation The surface was mechanically roughened with a roller nylon brush. In FIG. 5, 1 is an aluminum alloy plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers.
Here, the average particle size of the abrasive was 40 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum alloy plate. The rotation direction of the brush was the same as the movement direction of the aluminum alloy plate. The rotation speed of the brush was 200 rpm.

(B) Alkali Etching Treatment An etching treatment was performed by spraying using an aqueous solution having a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C., thereby dissolving 10 g / m ^{2 of the} aluminum alloy plate. Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmutting treatment was a waste liquid from a step of performing an electrolytic surface roughening treatment using alternating current in an aqueous nitric acid solution.

(D) Electrolytic roughening treatment An electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is the waveform shown in FIG. 1. The time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, and a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 2 was used.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum alloy plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(E) Alkaline etching treatment An etching treatment by spraying is performed at 60 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve 1.0 g / m ^{2 of the} aluminum alloy plate. The smut component mainly composed of aluminum hydroxide generated when the electrolytic surface roughening treatment was performed using alternating current was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmutting treatment was a waste liquid from a step of performing an electrolytic surface roughening treatment using alternating current in an aqueous nitric acid solution.

(G) Electrolytic surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 1. The time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, and a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 2 was used.
The current density was 25 A / dm ² at the current peak value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum alloy plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(H) Alkali etching treatment An aqueous etching solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass is subjected to an etching treatment by spraying at 32 ° C., and 0.5 g / m ^{2 of the} aluminum alloy plate is dissolved. The smut component mainly composed of aluminum hydroxide generated when the electrolytic surface roughening treatment was performed using alternating current was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Anodizing treatment was performed using phosphoric acid as the electrolytic solution. The electrolytic solution had a phosphoric acid concentration of 22% by mass and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 1.5 g / m ² .
For the anodized film formed by the above procedure, the average pore diameter (surface average pore diameter) in the surface layer of the anodized film and the average value of the maximum diameter inside the micropore (average value of the maximum diameter in the pore) are as follows: It measured in the procedure of. The results are shown in Table 3.
Surface average pore diameter: An ultrahigh resolution SEM (Hitachi S-900) was used to measure the pore diameter in the surface layer of the anodized film. The surface was observed at a magnification of 150,000 times, and an average value was obtained by randomly extracting 50 pores without performing a vapor deposition treatment imparting conductivity at a relatively low acceleration voltage of 12 V. The standard deviation error was ± 10% or less.
Measuring method of the average value of the maximum diameter in the pore: The maximum diameter inside the micropore is the ultra-high resolution of the side surface (commonly called the fracture surface) of the cracked part that occurs when the aluminum alloy plate after anodizing is bent. A type SEM (Hitachi S-900) was used and observed. The maximum diameter portion inside the micropore on the fracture surface of the anodized film was observed at a magnification of 150,000 times without applying a vapor deposition treatment that imparts conductivity at a relatively low acceleration voltage of 12 V, and 50 pieces The pores were randomized to obtain an average value. The standard deviation error was ± 10% or less.

(K) Hydrophilization treatment Hydrophilic treatment (alkali metal silicate treatment) was performed by immersing in a treatment tank of 1 mass% aqueous solution of sodium silicate No. 3 having a liquid temperature of 20 ° C. for 10 seconds. Then, the water washing by the spray using well water was performed.

[Manufacture of lithographic printing plate precursor]
An image recording layer was formed on the support obtained by the above procedure by the following procedure to obtain a planographic printing plate precursor.

(1) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support produced by the above procedure so that the dry coating amount is 20 mg / m ^2. An undercoat layer was formed on top.
<Coating liquid for undercoat layer (1)>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

(2) Formation of image recording layer The following image recording layer coating solution (1) was bar coated on the above support having an undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and a dry coating amount of 0.6 g. An image recording layer of / m ² was formed to obtain a lithographic printing plate precursor.

<Image recording layer coating solution (1)>
-Polymer fine particle aqueous dispersion (1) 20.0 g
・ Infrared absorbing dye (2) [The following structure] 0.2g
・ Polymerization initiator Irgacure250 (Ciba Specialty Chemicals) 0.5g
-Polymerizable compound SR-399 (Sartomer) 1.50 g
・ Mercapto-3-triazole 0.2g
・ BYK336 (Byk Chimie) 0.4g
・ KlucelM (Hercules) 4.8g
・ ELVACITE4026 (Ineos Acrylica) 2.5g
・ N-propanol 55.0g
・ 2-butanone 17.0g

In addition, the compounds described by trade names in the above composition are as follows.
IRGACURE 250: (4-methoxyphenyl) [4- (2-methylpropyl) phenyl] iodonium = hexafluorophosphate (75% by mass propylene carbonate solution)
・ SR-399: Dipentaerythritol pentaacrylate
BYK 336: modified dimethylpolysiloxane copolymer (25% by mass xylene / methoxypropyl acetate solution)
・ KLUCEL M: Hydroxypropyl cellulose (2 mass% aqueous solution)
ELVACITE 4026: Hyperbranched polymethyl methacrylate (10% by mass 2-butanone solution)

(Production of polymer fine particle aqueous dispersion (1))
A 1000 ml four-necked flask was equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and introduced with nitrogen gas to perform deoxygenation, and then polyethylene glycol methyl ether methacrylate (PEGMA Examples 1 to 12) 17-23 and Comparative Examples 1-6, the average repeating unit of the ethylene glycol chain (EO chain) was 9, and in Examples 13-16, the average repeating unit of the ethylene glycol chain was changed as shown in Table 3. ) 20 g, distilled water 200 g and n-propanol 200 g were added and heated until the internal temperature reached 70 ° C. Next, a premixed mixture of 10 g of styrene (St), 70 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization progressed 98% or more at the stage of reaction for a total of 20 hours, and a polymer fine particle aqueous dispersion (1) having a mass ratio of PEGMA / St / AN = 20/10/80 was obtained. The particle size distribution of the polymer fine particles had a maximum value at a particle size of 150 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. And the frequency of appearance of each particle size was plotted and obtained. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

(3) Formation of oxygen barrier layer In Table 3, for those described as having an oxygen barrier layer, the oxygen barrier layer coating solution (1) having the following composition was further bar coated on the image recording layer, The plate was oven dried at 120 ° C. for 60 seconds to form an oxygen barrier layer having a dry coating amount of 0.15 g / m ² to obtain a lithographic printing plate precursor.

<Coating liquid for oxygen barrier layer (1)>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[Evaluation of lithographic printing plate precursor]
The lithographic printing plate precursor obtained by the above procedure was evaluated as follows. The results are shown in Table 4.

(1) Evaluation of printing durability The obtained lithographic printing plate precursor was subjected to an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi on a Fujifilm Corporation Luxel PLASETTER T-6000III equipped with an infrared semiconductor laser. Exposed. The exposure image included a solid image and a 50% halftone dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After dampening water and ink were supplied by the standard automatic printing start method of Lithrone 26 and developed on the machine, printing was performed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Evaluate printing durability by assuming the number of copies to be printed when the value measured with a Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material is 5% lower than the measured value for the 100th printed sheet. did. The results are shown in Table 4 (see the following for the indicators of ○, ○ △, Δ, and Δx).
○… More than 50,000 copies ○ △… More than 40,000 copies and less than 50,000 copies △… More than 30,000 copies and less than 40,000 copies △ ×… Less than 30,000 copies (2) Dirt resistance evaluation Blanket after printing 10,000 copies The dirt was visually confirmed and evaluated according to the following criteria.
○… Blanket is not dirty ○ △… Blanket is slightly dirty but good △… Blanket is in acceptable range △ ×… Blanket is dirty and printed matter is clearly dirty ( 3) Evaluation of micro-corrosion stains The obtained lithographic printing plate precursor was conditioned at 25 ° C. and 70% RH for 1 hour with interleaf and packaged with aluminum kraft paper, and then in an oven set at 60 ° C. Heating was performed for 5 days.
Thereafter, the temperature was lowered to room temperature, and then the plate was attached to the plate cylinder of the printing machine LITHRONE 26 (manufactured by Komori Corporation) without developing.
Standard automatic of LITHRONE26 using dampening water of Equality-2 (manufactured by Fujifilm) / tap water = 2/98 (volume ratio) and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After supplying dampening water and ink by the printing start method and developing on the machine, 500 sheets were printed on Tokishi Art (76.5 kg) paper.
The 500th printed matter was visually confirmed, and the number of print stains of 20 μm or more per 100 cm ² was calculated. The results are shown in Table 4.
◎ ... Less than 20 fine corrosion stains (per 80 cm ² )
○ ... 21-50 fine corrosion stains (per 80 cm ² )
○ △ ... 51-80 fine corrosion stains (per 80 cm ² )
Δ: 81 to 100 fine corrosion stains (per 80 cm ² )
△ ×… 101-150 minute corrosion stains (per 80 cm ² )
×… 151 or more micro-corrosion stains (per 80 cm ² )
If the number of stains is 200 or less per 100 cm ² , it can be evaluated as having excellent resistance to severe stains.

DESCRIPTION OF SYMBOLS 1 Aluminum alloy plate 2, 4 Roller-like brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum alloy plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic treatment liquid 15 Electrolytic solution supply port 16 Slit 17 Electrolytic solution Passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 40 Main electrolytic tank 50 Auxiliary anode tank 410 Anodizing device 412 Power supply tank 413 Intermediate tank 414 Anodizing tank 416 Aluminum alloy plate 418, 426 Electrolytic solution 420 Anode 422, 428 Pass roller 424 Nip roller 430 Cathode 434 DC power supply 436, 438 Liquid supply nozzle 440 Shielding plate 442 Drain outlet

Claims (9)

An image recording layer having (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a polymer is printed on the support, and the image recording layer in the non-exposed area is printed. In a lithographic printing plate precursor removed with ink and / or fountain solution,
In the support, the density of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface is 35000 pieces / mm ² or more , and the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface is 2500 pieces / mm. ² or less, and the peak count value of the Al—Fe-based intermetallic compound measured using an X-ray diffractometer (XRD) is 400 cps or less, and the peak count value of the AlFeSi-based intermetallic compound is 30 cps or more. A lithographic printing plate precursor produced by using an aluminum alloy plate. 2. The lithographic printing plate precursor according to claim 1, further comprising an oxygen barrier layer on the image recording layer . 2. The lithographic printing plate precursor as claimed in claim 1, wherein an oxygen barrier layer is not provided on the image recording layer . The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the (D) polymer has an alkylene oxide chain . The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the (D) polymer is in the form of particles . An anodized film having micropores is formed on the surface of the support on the side on which the image recording layer is formed, and the average pore diameter in the surface layer of the anodized film is 10 to 75 nm. The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the average value of the maximum diameter is 1.1 to 3.0 times the average pore diameter . The lithographic printing plate precursor as claimed in claim 6, wherein the anodized film is formed by an anodizing treatment using an electrolytic solution containing sulfuric acid or phosphoric acid . The lithographic printing plate precursor as claimed in any one of claims 1 to 7, wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method . The aluminum alloy plate is obtained by continuous casting in which molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. The lithographic printing plate precursor as described in any one of 1 to 7.