JPH05171085A - Ink and ink jet printer - Google Patents

Abstract

PURPOSE:To obtain a difficulty foamable ink which is excellent in infrared absorptivity, does not undergo chemical change even when repeatedly exposed to high temperatures and does not form solid deposits on the surface of a ther mal head by incorporating a phthalocyanine compound of a specified formula. CONSTITUTION:An ink for an ink jet printer is obtained by incorporating a phthalocyanine compound of the formula (wherein M is Cu, Fe, Cr, Mn, Co, Ni, Zn, Cd or Ag; and R is CO2H or CO2NH4). The above compound has excellent infrared absorptivity and can be used together with another water-soluble dye. Therefore, when used as an ink for setting, it can attain a high visual density, can afford sufficient recognition in an optical character recognizer and a barcode type scanner in which an emission diode or a semiconductor laser in the red or near-red region of 630-940nm is used, and can be used as an ink for printers of such devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ink composition, particularly a fine ejection port (nozzle hole) provided in a recording head.
The present invention relates to a composition of an ink having an infrared absorbing property, which is suitable for an inkjet recording system in which ink is ejected and ejected and recording is performed by the droplets, and an inkjet printer using this ink.

[0002]

2. Description of the Related Art Optical character recognition scanning devices (OCR, OMR), which have been used in ATMs and the like that can be used to enter passbooks, and recently used in various fields such as physical distribution management and product management. The bar code type scanning device that has come to be used is a 632.8 nm He-Ne laser,
Since 660 nm light-emitting diode, 670 nm semiconductor laser, 690 nm light-emitting diode, 780 nm semiconductor laser, 940 nm infrared light-emitting diode, etc. are used as the light source, the printers for these scanning devices use red light or near red light. It is necessary to have sensitivity to external light, and a dot type printer using a pigment such as carbon black as a coloring agent has been used. However, the dot type printer has a problem that the printing sound is loud. Further, if there is a step on the recording medium, there is a problem that the wire pin of the recording head is caught at the step and pin breakage occurs or pin wear is accelerated, and the reliability of the recording head and the printer is impaired.

Therefore, in recent years, an inkjet ink containing a specific dye that absorbs infrared light and an inkjet printer using the same have been actively developed. For example, a method in which a chromium complex salt dye is combined with a specific polar substance (JP-A-56-135568), and a method in which a specific dye such as sulfa black 1 and an anticoagulant are combined (JP-A-57).
-14660) and the like have been proposed. These methods not only have the property of absorbing infrared light, but also pay attention to the storage stability as an ink in which the physical properties of the ink do not change during long-term storage and solids do not precipitate. Has been done.

However, the ink used in the ink jet printer is required to satisfy the following conditions in addition to the above characteristics in order to obtain good recording.

(1) Physical properties such as viscosity, surface tension, electrolysis, density, etc. are within proper ranges according to the ink ejection characteristics of the recording head.

(2) During long-term use, solid content is deposited due to a chemical change between the material of the recording head or a part that holds the ink and the ink, or a chemical change due to heat acting on the ink. It does not occur or the physical properties of the ink do not change.

(3) The nozzle hole of the recording head of an ink jet printer generally has a diameter of about 10 to 80 μm, and if the nozzle hole is clogged, or even if it is not completely clogged, solids and sticky substances adhere to the vicinity of the nozzle. Or, if the physical property value of the ink in the nozzle, especially the viscosity changes greatly, the recording property, ejection stability, and ejection responsiveness deteriorate. Therefore, the nozzle holes of the recording head do not become clogged and the ink in the nozzle holes does not thicken during recording pause.

(4) A print density required for recording can be obtained.

Generally, when an attempt is made to increase the print density by increasing the dye content in the ink, the above-mentioned (3) clogging of the nozzle holes tends to occur. Therefore, a dye having a high solubility in a solvent used for ink and a high extinction coefficient (ability to absorb light of a certain wavelength) is required.

(5) The ink is quickly fixed on the recording material, and the dots do not have irregular bleeding.

(6) The recorded image has water resistance, light resistance, and scratch resistance.

Further, thermal energy corresponding to the recording signal is applied to the ink in the recording head, and the energy is ejected and ejected as droplets from the nozzle holes of the recording head to form flying droplets, and a dot image is formed on the recording medium. In an inkjet printer for recording, it is necessary to improve the repeated service life (durability life) of the recording head in order to improve the service life of the apparatus.

In the recording head as described above, a thermal head used in a facsimile or the like is formed in the ink flow path in the recording head, and the thermal head is caused to generate heat in response to a recording signal, thereby causing bubbles in the ink. It is generated and droplets are ejected and ejected at this pressure. For this reason, factors that determine the service life of the recording head applied to the recording method as described above include not only the life of the thermal head provided but also the deposition of solid matter on the surface thereof. That is, since the ink receives high heat during repeated generation and disappearance of bubbles, it is expected that the thermally unstable ink undergoes a chemical change to deposit a solid matter.

Actually, when the generation and disappearance of bubbles are continued for a long time, as a result, insoluble matter is generated and deposited near the surface of the thermal head, which makes it difficult for the thermal head to generate heat, and the recording head cannot be ejected. What happens is experienced and observed in many experiments.

Further, by applying pressure to the ink using the electromechanical conversion means, the ink is ejected and ejected as droplets from the nozzle holes of the recording head to form flying droplets, and an ink jet for recording a dot image on the recording medium. In the printer, in order to improve the reliability of the device, it is necessary to use an ink that hardly foams.

In this recording head, a voltage is applied to a piezoelectric element, which is an electromechanical converting means, which is adhered to a position called a pressure chamber in an ink flow path in the recording head, whereby the piezoelectric element is bent and pressure is applied. The volume of the chamber is reduced and ink droplets are ejected and ejected. However, if gas (air bubbles) is present in the ink flow path of the recording head in addition to the ink, even if the volume of the pressure chamber is reduced, the volume of the air bubbles contained therein is reduced, and The drops will not be ejected.
A possible cause of the infiltration of air bubbles into the ink flow path is to rapidly flow the ink that easily foams.

Actually, when the ink which is difficult to bubble is used, bubbles are not generated or the ejection failure is not generated in the ink flow path. However, when the ink which easily foams is used, the ink flow It has been experienced and observed in many experiments that the recording head cannot be ejected even if air bubbles are generated in the passage and therefore the piezoelectric element is bent and the volume of the pressure chamber is reduced.

[0018]

However, the above-mentioned conventional technique has the following drawbacks.

(1) When the ink of JP-A-56-135568 is used in an ink jet printer which generates droplets by applying thermal energy to the ink in the recording head, the ink is ejected and ejected tens of thousands of times. However, solid matter was found to be attached to the surface of the thermal head, and when the ejection and ejection of droplets were continued for tens of thousands of times, the recording head was unable to eject. When this ink was used in an ink jet printer that generates droplets by applying pressure to the ink using electromechanical conversion means, the printer that was printing before leaving was left at room temperature for 2 to 3 days. After that, when I tried to print, it became impossible to print.
When the nozzle hole of the recording head of the printer was observed with a microscope, solid matter was found to be deposited in the nozzle hole.

(2) When the ink of JP-A-57-14660 was used in an ink jet printer which generates droplets by applying pressure to the ink using electromechanical conversion means, ejection failure of the head occurred. When the ink flow path in the recording head was observed with a magnifying glass, a large amount of air bubbles having a diameter of about 0.1 mm were present.

(3) In the prior arts other than the above-mentioned two cases, inks have been developed to individually satisfy the required performances, but by combining them, all or a plurality of required performances are simultaneously satisfied. The ink to make it has not been developed yet.

Therefore, the present invention has been made to solve such a drawback as a result of the extensive researches conducted by the authors over the years, and is not only excellent in infrared absorption but also the above-mentioned requirements. Satisfy all the characteristics (1) to (6).

Furthermore, a characteristic characteristic of an ink jet printer that generates droplets by applying thermal energy to the ink in the recording head is that it undergoes a chemical change even when repeatedly exposed to high temperatures, and solids are formed on the surface of the thermal head. Things do not settle.

Further, it is difficult to foam, which is a required characteristic peculiar to an ink jet printer which generates droplets by applying pressure to ink using electromechanical conversion means.

It is an object of the present invention to provide an ink that satisfies all of these and an ink jet printer that uses this ink.

[0026]

The ink of the present invention is characterized by containing a phthalocyanine compound of Chemical formula 2 as an ink for forming a recorded image.

[0027]

[Chemical 2]

[Wherein M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . In addition, the inkjet printer of the present invention is an inkjet printer in which thermal energy is applied to ink to eject and eject as droplets from a nozzle hole of a recording head to form flying droplets and to record a dot image on a recording medium. ,
It is characterized in that the ink contains a phthalocyanine compound of Chemical formula 3.

[0029]

[Chemical 3]

[In the formula, M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . Further, in the ink jet printer of the present invention, by applying pressure to the ink using the electromechanical conversion means, the ink is ejected and ejected as droplets from the nozzle holes of the recording head to form flying droplets, and a dot image is formed on the recording medium. In the ink jet printer for recording, the ink contains the phthalocyanine compound of Chemical formula 4.

[0031]

[Chemical 4]

[In the formula, M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . ]

[0033]

EXAMPLES The present invention will be described below based on examples.

The basic composition of the ink used in the present invention is, firstly, a colorant and secondly a solvent. Specific examples of the colorant include phthalocyanine compounds having the following chemical structures. Two or more of these may be mixed and added.

[0035]

[Chemical 5]

[0036]

[Chemical 6]

[0037]

[Chemical 7]

[0038]

[Chemical 8]

[0039]

[Chemical 9]

[0040]

[Chemical 10]

[0041]

[Chemical 11]

[0042]

[Chemical 12]

[0043]

[Chemical 13]

[0044]

[Chemical 14]

[0045]

[Chemical 15]

[0046]

[Chemical 16]

[0047]

[Chemical 17]

[0048]

[Chemical 18]

[0049]

[Chemical 19]

[0050]

[Chemical 20]

[0051]

[Chemical 21]

[0052]

[Chemical formula 22]

Other water-soluble dyes are added if necessary. As water-soluble dyes, water-soluble, stability, light resistance,
As a material satisfying human body safety and other required performance, for example, C.I. I. Direct black 17,19,
32, 51, 71, 108, 146, 154, 168;
C. I. Direct Blue 6,22,25,71,8
6,106,199; C.I. I. Direct Red 1,
4, 17, 28, 83; C.I. I. Direct yellow 1
2,24,86,98,142; C.I. I. Acid Black 2, 24, 31, 52, 112, 118; C.I. I.
Acid Blue 9, 22, 93, 104, 167, 23
4; C.I. I. Acid Red 1,32,51,52,1
15,180,317; C.I. I. Acid yellow 1
1, 17, 25, 61 and the like.

As a solvent, a mixture of water (deionized water or pure water) and various water-soluble organic solvents is used as a main liquid medium component. As a water-soluble organic solvent, the vapor pressure is low,
Polyethylene glycols such as polyethylene glycol and polypropylene glycol that are difficult to evaporate and dry; alkylene glycols such as ethylene glycol and triethylene glycol; polyhydric alcohols such as glycerin, ethylene glycol methyl (ethyl) ether and diethylene glycol methyl (ethyl) ether. Examples include lower alkyl ethers, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and solvents having a low surface tension such as ethanol and isopropanol.

In addition to the above components, various additives can be used in order to further optimize the physical properties and improve the properties. Examples thereof include viscosity modifiers, surface tension modifiers and antifungal agents.

The content of the phthalocyanine compound of formula 23 in the ink of the present invention is 0.1 to 10% by weight, more preferably 0.3 to 4% by weight based on the total weight of the ink in any chemical structure. It is desirable to set it within the range of%.

[0057]

[Chemical formula 23]

[Wherein M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . The content of the water-soluble organic solvent is in the range of 0 to 70% by weight, more preferably 2 to 40% by weight, based on the total weight of the ink. The water content is 1 with respect to the total weight of the ink.
It is desirable that the amount be in the range of 0 to 90% by weight, more preferably 40 to 85% by weight.

Next, the structure of the recording head of the ink jet printer of the present invention and the method of driving the printer will be described.

In FIGS. 1, 2 and 3, the pressure is applied to the ink using the electromechanical conversion means to eject and eject the ink as droplets from the nozzle holes of the recording head to form flying droplets. It is a figure which shows one Example of the 1st inkjet printer of this invention which records a dot image on top.

FIG. 1 is a plan view of the first substrate of the recording head,
2 is a cross-sectional view of the recording head during ejection of ink droplets, and FIG. 3 is a perspective view of the recording head. In each figure, the same numbers indicate the same things. Further, in FIG. 3, the number of nozzles is 5 for simplicity.

Reference numeral 10 designates a first substrate, which is a plastic resin such as polysulfone or polycarbonate, or glass,
Molded ceramics by laser molding, glass plates processed by photolithography technology, or photo-curable resin fused or bonded to glass plates or metal plates processed by photolithography technology. Is. Reference numeral 11 is a nozzle hole, 13 is a pressure chamber, 15 is a common ink chamber, 12 and 14 are nozzle side and supply side ink flow paths, and the first substrate 10
It is formed by carving. Reference numeral 16 is an ink supply port.
The piezoelectric element 17 is adhered onto the second substrate at the position shown in the figure after the second substrate 18 is welded or adhered to the first substrate 10 to form an ink flow path. 20 is a flying ink drop,
Reference numeral 21 is a recording medium.

In the first ink jet printer driving method according to the present invention, the ink 19 supplied from the ink supply port 16 of the recording head formed by adhering or welding the first substrate 10 and the second substrate 18 is used. By applying a voltage to the piezoelectric element 17 adhered to the position facing the pressure chamber 13 of the second substrate 18 with the nozzle hole 11 filled, the piezoelectric element 17 bends and the pressure chamber 13 The volume is reduced and the ink droplets 20 are ejected and ejected and fly toward the recording medium 21.

In FIGS. 4, 5, and 6, thermal energy is applied to the ink to eject and eject as droplets from the nozzle holes of the recording head to form flying droplets, and a dot image is recorded on the recording medium. It is a figure which shows one Example of the 2nd inkjet printer of this invention which does.

FIG. 4 is a sectional view of the recording head during ejection of ink droplets, FIG. 5 is a sectional view taken along the line AB in FIG. 4, and FIG. 6 is a recording in which five thermal heads shown in FIGS. It is a perspective view of a head. In each figure, the same numbers indicate the same things.

The recording head is composed of a thermal head 41 used for heat-sensitive recording such as facsimile and a substrate 40. The substrate 40 is formed by molding plastic resin, glass, or ceramic by molding or laser processing, processing a glass plate by photolithography technology, or photo-curing a photocurable resin that is fused or adhered to a glass plate or a metal plate. It is processed and shaped using technology. The thermal head 41 includes a protective film 42 formed of silicon oxide, silicon nitride, tantalum oxide, electrodes 43-1 and 43-2 formed of gold, copper, aluminum, tantalum-silicon oxide, or the like. The heating resistor 44 is made of polysilicon, the heat storage layer 45 made of glass or the like, and the substrate 46 having a good heat dissipation property such as alumina (aluminum oxide).

In the second method for driving an ink jet printer according to the present invention, the electrode 43 is provided in a state where the ink flow path of the recording head formed by adhering or welding the substrate 40 and the thermal head 41 is filled with the ink 47. -1,43
When an electric signal is applied to −2, a portion of the thermal head 41 indicated by n rapidly heats up, bubbles are generated in the ink 47 in contact there, and the ink is ejected and ejected by the pressure.
Ink droplets 49 are formed from the nozzle holes 48 and fly toward the recording medium 50.

Now, the present invention will be described in more detail with reference to Examples and Comparative Examples of printers using the above recording head and ink, and the effects will be illustrated together.

Example 1 The following components were mixed, sufficiently stirred to dissolve, and then filtered using a membrane filter having a hole diameter of 0.8 μm to prepare a water-soluble ink.

[0070]

Colorant: Phthalocyanine compound of Chemical formula 24 2.5% by weight Surface tension adjuster: Polyoxyethylene alkyl ether (surfactant) 1.0% by weight Solvent: Triethylene glycol 2.0% by weight Glycerin 20. 0 wt% water 74.5 wt%

[0071]

[Chemical formula 24]

This water-soluble ink is supplied to the first ink jet printer of the present invention using a recording head composed of a first substrate 10 and a sheet-shaped second substrate 18 made of polycarbonate by molding. Then, ink droplets were ejected and ejected. The nozzle hole 11 of the recording head has a short side of 60 μm, a long side of 70 μm, and a height of 30.
It has a trapezoidal shape of μm, the number of nozzle holes is 9, the nozzle pitch is 350 μm, and the driving voltage of the piezoelectric element is 100 at room temperature.
V, frequency is 2.0 kHz.

FIG. 7 is a perspective view of the recording head during ejection of ink droplets according to the first embodiment. The ink supply port 16 to the common ink chamber 15, the supply-side ink flow passage 14, the pressure chamber 13, and the nozzle-side ink flow passage. 12 and the nozzle hole 11 are filled with ink, and no bubbles enter. Therefore, printing can be performed without missing dots.

Under the above conditions, neutral PPC paper (made by Fuji Xerox), acid paper register paper (made by Daishowa Paper Co., Ltd.), 45 kg fine paper (made by Tojo Paper Co., Ltd.), recycled paper "Yamayuri" (Honshu) The time until the ink was dried was visually observed to be 1 second or less. Further, the print density of the printed matter was measured with a densitometer (print contrast meter PCM-II, manufactured by Macbeth Co.).
When the reflectance of the printed dots was measured by inserting a filter having a visible light type sensitivity characteristic showing maximum absorption at about 550 nm into a densitometer, the reflectance was 15% on average, although it varied depending on the recording medium. .. When the print density is calculated from this, the optical reflection density OD value is 0.8. When the OD value for the filter is 0.8, a sufficient blackness is visually perceived.

When a filter having a near-infrared type sensitivity characteristic showing maximum absorption at about 950 nm was inserted into a densitometer and the reflectance of the printed dots was measured, the dispersion due to the recording medium was averaged and the reflectance was 15%. Met. When the print density is calculated from this, the optical reflection density OD value is 0.8. An OD value of 0.8 for the filter is sufficient for recognition by the optical character recognition scanning device and the bar code type scanning device described above.

Next, when the ink jet printer was left at room temperature and printing was carried out one week later, the printing was successful. When the nozzle holes of the recording head of the printer were observed with a microscope, the nozzle holes were filled with ink, and no precipitation of solid content was observed.

The above evaluation results are shown in Table 1 together with the results of Examples 2, 3, 4 and Comparative Example 1 described below.

[0078]

[Table 1]

Example 2 A glass layer 45 having a thickness of 5 μm was formed on an alumina substrate 46 by screen printing. Subsequently, as a heating resistor 44, TaSiO ₂ was formed to a thickness of 1000 angstrom and gold was formed to electrodes 43-1 and 43. -2 as 30
After stacking to a thickness of 00 Å, a heating resistor pattern of 50 μm × 200 μm was formed by selective etching. Next, the SiO ₂ layer is sputtered 35
After forming a protective film 42 with a thickness of 00 angstroms to form an electric / thermal converter on the substrate to form a thermal head 41, a polysulfone substrate 40 having ink channels of width 50 μm × depth 50 μm carved is used. It joined so that a flow path and a heating resistor might match. Subsequently, the nozzle surface was polished so that the distance between the tip of the heating resistor and the nozzle hole surface 48 was 250 μm, and the recording head of the second inkjet printer of the present invention was prepared. The ink of Example 1 was ejected using this recording head. When the recording head was driven at a frequency of 5 kHz, an applied voltage of 40 V and an applied pulse width of 10 μsec, the recording head was ejected normally even after 100 million ejections of ink droplets. When this recording head was disassembled and the thermal head portion was observed with a microscope, no solid content was adhered to the protective layer.

Example 3 Under the same conditions as in Example 1, a water-soluble ink having the following components was prepared.

[0081]

Colorant: phthalocyanine compound of Chemical formula 25 1.0 wt% C.I. I. Direct Black 168 1.5% by weight Chelating agent: Ethylenediaminetetraacetic acid disodium 0.2% by weight Antifungal agent: Compound of formula 26 0.3% by weight Solvent: Polyethylene glycol # 200 15.0% by weight Water 82.0% by weight %

[0082]

[Chemical 25]

[0083]

[Chemical formula 26]

A book using a recording head made of this ink, which is formed by a photolithography technique, comprising a first substrate 10 having an ink channel formed in a glass plate and a second substrate 18 made of a glass plate having a thickness of 0.3 mm. It was supplied to the first inkjet printer of the invention, and ink droplets were ejected and ejected. The nozzle hole 11 of the recording head has a rectangular shape with a length of 40 μm and a height of 25 μm, the number of nozzle holes is 24, the nozzle pitch is 140 μm, and the driving voltage of the piezoelectric element is 120 V at room temperature.
The frequency is 2.5 kHz.

Also in this embodiment, as shown in FIG. 7, no bubbles were found in the ink flow path during ink ejection. When printing was performed on the same recording medium as in Example 1 and the time until the ink dried was visually observed, it was 10
It was about a second. Furthermore, when the print density of the printed matter was measured by a densitometer, the reflectance when a filter having a visible light type sensitivity characteristic showing maximum absorption at about 550 nm was inserted into the densitometer was 5% on average for each recording medium. there were. When the print density is calculated from this, the optical reflection density OD value is 1.3.
Further, the reflectance when a filter having a near-infrared type sensitivity characteristic showing maximum absorption at about 950 nm was inserted into the densitometer was 30% on average for each recording medium. When the print density is calculated from this, the optical reflection density OD value is 0.5. Even if the OD value for this filter is 0.5, it can be recognized by the optical character recognition scanning device and the barcode scanning device described above.

Next, when this ink jet printer was left at room temperature and printing was carried out one week later, it was possible to print normally. When the nozzle holes of the recording head of the printer were observed with a microscope, the nozzle holes were filled with ink, and no precipitation of solid content was observed.

[Example 4] The ink of Example 3 was ejected using the second ink jet printer of the present invention used in Example 2. The drive conditions of the recording head are the same as in the second embodiment. In this case as well, the ejection was normally performed even after the ejection ejection of 100 million times.
Further, when the recording head was disassembled and the thermal head portion was observed with a microscope, no solid content was adhered to the protective layer.

[Comparative Example 1] A water-soluble ink was prepared by mixing the following components in the same manner as in JP-A-57-14660.

[0089]

## EQU00003 ## Sulfa black 1 1.0% by weight Direct black 163 3.25% by weight Sodium 2-pyridimethiol-1-oxide 0.1% by weight Tetrasodium ethylenediaminetetraacetate 0.2% by weight 2-hydroxyethyl-substituted polyethylene Imine 6.0% by weight Sodium carbonate 0.2% by weight Sodium bicarbonate 0.1% by weight Poroethylene glycol # 200 5.0% by weight N-methyl-2-pyrrolidone 4.0% by weight Ethylene glycol monobutyl ether 3.0 % By weight Water 77.15% by weight This water-soluble ink is ejected and ejected as a droplet from a nozzle hole of a recording head by applying pressure to the ink using an electromechanical conversion means to form a flying droplet for recording. It is supplied to an inkjet printer that records a dot image on the medium. The ink droplets were ejected injection. The structure, configuration and driving conditions of the recording head are the same as in the first embodiment.

FIG. 8 is a perspective view of the recording head of Comparative Example 1 during the ejection of ink droplets. 81 is a nozzle hole, 82 is a nozzle side flow path, 83 is a pressure chamber, 84 is a supply side ink flow path, 85 is a common ink chamber, 86 is an ink supply port,
The ink from the ink supply port 86 to the nozzle hole 81 is filled with ink. Further, 87 indicates bubbles. As described above, a large amount of bubbles 8 having a diameter of about 0.1 mm are provided in the common ink chamber 85, the supply-side ink flow passage 84, the pressure chamber 83, and the nozzle-side ink flow passage 82.
Infiltration of 7 is seen. Even if an attempt is made to reduce the volume of the pressure chamber 83 by applying a voltage to the piezoelectric element to bend the piezoelectric element in a state where there are bubbles in the pressure chamber 83, the volume of the volume reduction is absorbed by the bubbles, so that the ink is ejected. Not ejected and many missing dots occur during printing. This is because when the colorant Sulfa Black 1 is dissolved in water, it becomes very easy to foam.

[0091]

As described above, the present invention has the following excellent effects.

(1) The phthalocyanine compound of Chemical formula 27 is
All of them have excellent infrared absorption characteristics and can be used in combination with other water-soluble dyes. Therefore, by printing as ink, a high density can be secured by visual observation, and 630
nm to 940 nm red or near infrared light emitting diode or optical character recognition device using semiconductor laser (OC
R, OMR) and barcode type scanning devices can be sufficiently recognized, and can be used as ink in printers for these devices. Such an effect can be applied to all kinds of paper including recycled paper.

[0093]

[Chemical 27]

[In the formula, M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . (2) Any of the phthalocyanine compounds of Chemical formula 28 are stable against heat action and chemical change with glass, plastic, ceramics, rubber, etc. constituting the recording head and ink holding parts. is there. Therefore, the ink of the present invention is applied with thermal energy corresponding to the recording signal to the ink in the recording head, and this energy is ejected and ejected as a droplet from the nozzle hole of the recording head to form a flying droplet, which is then ejected onto the recording medium. Even when it is used in an ink jet printer for recording a dot image on a paper and repeatedly subjected to a thermal action, the ink does not undergo a chemical change, solids are deposited, or ejection failure is not caused. There is no chemical change with the material of the recording head or the parts that hold the ink during long-term use or during rest, so the solid deposition, the change in the physical properties of the ink, and the ejection failure that cause this do not occur. Does not occur.

[0095]

[Chemical 28]

[Wherein M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . (3) Water, polyalkylene glycols, alkylene glycols, glycerin, lower alkyl ethers of polyhydric alcohols, N- of the phthalocyanine compound of Chemical formula 29
Since the solubility of the ink of the present invention in a solvent such as methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone is very good, the ink of the present invention is applied to the ink in the recording head with thermal energy corresponding to a recording signal. Also, when this energy is used, the electromechanical conversion means is also used in the case of being used in an ink jet printer for recording a dot image on a recording medium by ejecting and ejecting as droplets from the nozzle hole of the recording head to form flying droplets. Even when used in an inkjet printer that records a dot image on a recording medium by ejecting and ejecting as a droplet from the nozzle hole of the recording head by applying pressure to the ink, the nozzle is also used. There is no precipitation of solids in the holes, adhesion of sticky substances, or a significant increase in the viscosity of the ink in the nozzle. It can be shaped.

[0097]

[Chemical 29]

[Wherein M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . (4) Any of the water-soluble phthalocyanine compound of Chemical formula 30 is very unlikely to foam, and therefore the ink of the present invention is applied with pressure by using electromechanical conversion means.
When used in an inkjet printer that forms jetting droplets by ejecting and ejecting as droplets from a nozzle hole of the recording head to record a dot image on a recording medium, the recording head and the printer can be operated under any driving condition. No bubbles are generated in the ink flow path.

[0099]

[Chemical 30]

[In the formula, M is Cu, Fe, Cr, Mn, C
o, Ni, Zn, Cd, or Ag, R is CO ₂ H,
Represents CO ₂ NH ₄ . (5) Further, according to the present invention, it is possible to secure ink storage stability, high ejection stability and ejection response, quick fixing of printed matter, and high printing quality, which are necessary characteristics common to inkjet printers. It also has the effect.

[Brief description of drawings]

FIG. 1 is a plan view of a first substrate of a recording head showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a recording head during ejection of ink droplets according to an embodiment of the present invention.

FIG. 3 is a perspective view of a recording head showing an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a recording head during ejection of ink droplets according to another embodiment of the present invention.

FIG. 5 is a sectional view of a recording head showing another embodiment of the present invention.

FIG. 6 is a perspective view of a recording head showing another embodiment of the present invention.

FIG. 7 is a perspective view of the recording head during ejection of ink droplets according to an embodiment of the present invention.

FIG. 8 is a perspective view of a recording head during ejection of ink droplets showing an example of a conventional technique.

[Explanation of symbols]

 10 First Substrate 11 Nozzle Hole 17 Piezoelectric Element 18 Second Substrate 20 Flying Ink Drop 21 Recording Medium 41 Thermal Head 48 Nozzle Hole 49 Flying Ink Drop 50 Recording Medium

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Claims (3)

[Claims] 1. An ink comprising a phthalocyanine compound of Chemical formula 1 as an ink for forming a recorded image. [Chemical 1] [In the formula, M is Cu, Fe, Cr, Mn, Co, Ni, Z
n, Cd, or Ag, and R represents CO ₂ H or CO ₂ NH ₄ . ] 2. An ink jet printer for recording a dot image on a recording medium by causing thermal energy to act on the ink and ejecting and ejecting it as a droplet from a nozzle hole of a recording head to record a dot image on a recording medium. Claim 1
An ink jet printer, characterized by using the described ink. 3. An ink jet for recording a dot image on a recording medium by applying pressure to the ink using an electromechanical conversion means to eject and eject as a droplet from a nozzle hole of a recording head to form a flying droplet. An inkjet printer, wherein the ink according to claim 1 is used as the ink.