DE2462017A1 - Rotogravure printing device - Google Patents

Description

1 BERLIN 33 BMUNCHEN

Augusta-Viktoria-Strasse 65 _n DIICPUI / C i 'DADTMCD Pienzenauerstrasse 2

Pat. Dr. Ing.Ruschke LT. KUobliNt & TAKNNtK Pat.-Anw.Dipl.-lng.

Pat. Pee-fng. DATCMTA M \ A / KlTC Hans E. Ruschke

Olaf Ruschke γΑΙ t IN I AIMWALI C 88 03

Telephone: 030 / | H ^ | ^ BERLIN-M ONCHEN ^Telephone: 089/987268

Telegram address: Telegram address:

Quadrature Berlin Qudadraiur Munich TELEXi 183786 TELEX: 522767

ι.Γ

research Inst., Inc., Port Washington, Long Island State of Me ".- York (V.St.v.A.)

'Rotogravure printing facility

The invention relates to a device for rotogravure printing and in particular a fin device for printing multi-page originals, with engravings comprising one or two rides can be produced by etching or engraving on gravure printing plates.

The processes currently in use are engravings for a number of pages to be printed, e.g. for 16, 20, 24, 28 etc. pages compiled and etched or engraved into the outside of a cylinder, which is hereafter used for the direct or offset printing of multi-page originals is used. Then the multiple pages are slit open, cut to size and folded into booklets in a predetermined manner, which are bound to a book at one edge, be clamped together or left loose. The engravings for the individual pages are in -

SAD

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the outside of a cylinder is etched or engraved in such a way that after the sheets are folded together, the individual Print pages are in the correct order. The imprint of each template therefore becomes one side of the printed one and folded product.

The preparatory work for etching or engraving of rotary printing cylinders multi-page documents are expensive, time consuming and essentially inflexible to print. The order of The sides of the product must be determined before the cylinder can be etched or engraved. Once this work has been carried out, changes on a single page often require all etchings or Engravings on all sides of the cylinder are removed, after which the entire cylinder is plated, etched or again must be engraved. Changes that are often desired are not implemented due to lack of time or costs. Because of the cost of making the impression cylinders and the difficulty of making changes rotogravure had only found limited use for these purposes. This printing process was therefore only used when a large number of prints should be made without changes. This was the case despite the high Printing quality that can be achieved with rotogravure compared to other printing processes.

Some difficulties which add to the cost of rotogravure and make it essentially inflexible make are created by etching or engraving the

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Originals of several pages on the impression cylinder. With other types of multi-sided printing, for example letterpress, similar difficulties were avoided by the use of page-sized plates. The image of the one to be printed Original is first created on the plates, after which a number of such plates for printing on the drums or cylinders was attached. In letterpress and lithographic printing, the coloring of the image and the transfer the colored image from the printing cylinder onto the printing material used a completely different process than rotogravure printing.

In letterpress or type printing, the printing elements are higher than the low-pressure parts of the printing plate. This higher located printing elements are colored, after which the color of these elements on the pressure-receiving material is transmitted. Due to this fact, interruptions act on the outside of the printing cylinder, for example through the plate edges or through the fastening means for the printing plates, provided that these are above the higher ones Printing elements do not protrude, not detrimental to the print.

In lithographic printing, the image is on the surface of a plate, cylinder or drum generated. This is done by sensitizing the surface, with the areas in the illustration part being wetted by the paint and holds back to print. The lithographic ink is thick and viscous and is returned by the sensitized districts.

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held. When printing, the color is transferred from these areas to the substrate that will receive the pressure. Since the The paint is thick and viscous, and since the unsensitized area is paint repellant, the transfer of the Color from the other districts no trouble. Should the lithographic ink settle in areas below are located on the surface of the plate, the ink will not transfer when printed because of its thickness and viscosity. At the Lithographic printing therefore have an effect on the outside of the cylinder or the drum in the form of interruptions Plate edges or fasteners for printing are not detrimental.

As already stated, in rotogravure printing the artwork is or is etched into the outside of the cylinder engraved. Here, small depressions are created on the outside that are filled with color for printing. The cylinder is passed through a container containing a very liquid paint or with such a paint flooded. Using a squeegee, the paint is wiped off the outside of the cylinder, but remains in the indentations and is transferred from these depressions to a base when it comes into contact with the cylinder is brought. In contrast to type or letterpress, in which the printing elements are raised and carry the color, as well as of lithography, where the retained color is on and above the surface of the plate, is at Gravure printing the color below the surface of the cylinder

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located. ·

Entering the liquid printing ink into the depressions on the outside of a gravure cylinder and the passage of the cylinder through a dye, and on one Ttakel over was previously a hindrance to the use of removable page-sized printing plates on the cylinder for rotogravure printing, since it was previously difficult to put several such plates on one cylinder like that. attach that to them while pressing remained stationary on the cylinder, while on the other hand it should be possible to replace individual plates, Another problem is the undesirable double image that can be caused by the edges of the plate and in the gaps between the .flatten accumulating printing ink result, as well as the ink splatter and the wear and tear when the plate edges run past the squeegee

The invention overcomes these and other difficulties eliminated associated with the use of plate assemblies in gravure printing.

The invention provides a printing plate for rotogravure printing with an inelastic pad made of a magnetically attractable material, with which the plate is attached to a magnetic Cylinder attached and held in place, roll plate on one side with recesses for receiving printing ink can be provided. Awake to attaching the printing plate to the magnetic cylinder during rotogravure printing the color sitting in the depressions is transferred to a printing substrate, which is then printed with the desired image target".

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After the plates have been placed on the cylinder and are held magnetically by this, the plates with the cylinder form a firmly coherent unit in the in the same way as if the image to be printed were etched or engraved directly into the cylinder surface. This is very important because it is certain that a high quality print will be made in the correct orientation if the one to be printed on Pad is brought into contact with the plates on the cylinder. One or more plates can be changed at the same time if changes are necessary or desired, so that in such a case not the entire etching or engraving needs to be renewed on the cylinder. The hours of work required to make such changes and The invention significantly reduces costs. Furthermore, prints can be made in large quantities, even if changes should or have to be made on one or more pages.

The invention will now be described in detail. In the accompanying drawings the

Fig.I is a diagrammatic representation of a for the purposes of Invention usable plate,

2 shows a vertical section through the plate along the line 2-2 in Fig. I with etched or engraved depressions for receiving the color for rotogravure printing,

3 shows a diagrammatic representation of a rotational depth

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printing cylinder with the printing plates attached to it according to Figures I and 2,

4 shows a detail from a sectional drawing along the line 4 - 4 in Fig. 3 showing an embodiment of the invention shows in which the space between the printing plates according to FIG. 3 is filled with a filler material is,

5 shows a schematic representation of an embodiment of the Invention used for direct rotogravure printing will,

6 shows a schematic representation of an embodiment of the Inventions used in offset printing and the

7 shows an illustration of the undercut cloth roller, which in the embodiment according to FIG. 6 as a transfer roller when carrying out the method according to the invention is used.

The plate shown in Fig.I and designated as a whole by 2 has a base 4 made of a magnetically attractable Material, such as steel, and a surface 6 made of a material suitable for etching or engraving. To this end Copper has proven to be particularly suitable, which is why it is generally used for cylinders for rotogravure printing,

The plate 2 should have a sufficient thickness so that it does not warp or deform during handling, etching or engraving. On the other hand, the record must not be like that

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be thick so that their curvature is made difficult to match the curvature of the magnetic cylinder. A plate with a total thickness of essentially not less than 0.2 mm and not more than 0.3 mm and with a copper coating for etching or engraving with a thickness of substantially not less than 0.05 mm and not more than 0.075 mm proved to be satisfactory.

As can best be seen from Fig. 2, the copper coating is 6 of the plate 2 is etched or engraved, the color-receiving depressions 8, II, 12 being produced, their width and depth is shown enlarged in Fig.2. For the purposes of the invention, the etching or engraving can be in the conventional Way to be executed. The dimensions of these engraved pits are usually measured in microns and have a different shade depending on the lightness or darkness of the color to be printed at the relevant point Breadth and depth. The copper coating 6 can be etched or engraved with the plate 2 lying flat, after which the plate 2 is bent and adapted to the curvature of the magnetic cylinder. On the other hand, the plate can also be bent first are, after which the copper coating 6 is etched or engraved. After the etching, the surface of the plate 2 can be coated with chrome be plated, as is common practice, if a wear-resistant surface and a long service life of the plate are desired is.

As can best be seen from Figure 3, the Plates adapted to the curvature of the cylinder are applied to them

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and held by the fact that the magnetized outside of the cylinder IO attracts the base 4 of the plates 2 magnetically. Depending on the format of the template to be printed, the plates 2 can be of different sizes. As best can be seen from Figure 3, the plates 2 are adapted to the outer side of the cylinder IO so that, after their contact with the cylinder IO its outside, with which the color image receiving material would gen gelan in contact otherwise is covered by the plates 2. The plates 2 are preferably dimensioned for a single printed page so that the abutting edges of the plates come into contact with the material receiving the color imprints between the printed individual pages during rotation printing. Depending on the arrangement of the printed pages on the material to be printed, the plates 2 can be curved and held on the magnetic cylinder IO so that the pages are printed top edge to bottom edge, bottom edge to top edge or side edge to side edge. As can best be seen from FIG. 3, the front and rear edges of the plates that meet axially on the cylinder are cut in such a way that they form an angle of 5, for example, with the axis of rotation of the cylinder 10. As will be described later, the abutting edges of the plates 2 (as can be seen from FIG. 4) can be filled with a filler material 12 for some rotogravure printing processes. A quick drying material, such as an epoxy material, compatible with the material of the plates 2 and of the cylinder 10

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that does not dissolve in the printing ink, that is wear-resistant and non-porous, and that as a viscous liquid or can be applied as a paste and dries evenly and smoothly, is the preferred filler material.

As can best be seen from Figures 5 and 6, can a magnetic cylinder IO with plates 2 magnetically held thereon is used for direct rotary printing are, as shown in Fig. 5, or for offset gravure, as shown in Figure 6. As in Fig.i? shown, the magnetic cylinder IO with the plates 2 magnetically held on this in the frame 20 a Rotogravure press and a 'conventional, drive, not shown, rotated in the direction of the arrow.

A pressure cylinder 22 with the conventional outer covering 24, for example consisting of rubber, is inserted into the frame 20 inserted and rotated in the direction of the arrow. Between the plates 2 on the cylinder IO and the printing cylinder For example, printing material 26 made of paper is inserted in the direction of the arrows. When moving the substrate 26 between the plates 2 and the printing cylinder 22, ink is drawn from the depressions on the outside of the plates 2 when the depressions come into contact with the printing material 26, transferred to the printing material 26 and on this a printed Image of the template generated. The elastic outer covering 24 on the pressure cylinder 22 can have undercuts in those areas that while pressing under the

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Plate gaps are located so that the pressure in these areas is kept low during the printing process.

In the embodiment shown in FIG. 5, the magnetic cylinder IO is guided through a dye container 28 as it rotates in the direction of the arrow. The printing ink remaining on the upper side of the plates 2 on the cylinder IO is scraped off by the squeegee JO, with ink remaining in the depressions 8, II, 12 according to FIG 2 come into contact with the printing material 26 on the printing cylinder 22.

When the ink is stripped from the outside of the plates 2, printing ink remaining in the depressions, such as 8, II, 12, in the embodiment according to FIG. 5, the squeegee 30 brushes paint into the gaps between the plates 2, unless this column is filled with a filler material 13 (Fig. 4) is filled out. If color remains in the empty columns, this color is transferred from the Plates 2 on the cylinder IO out onto the printing material 26 when this comes into contact with the plate gaps. Because of the size of the plates and the places of the gaps between the individual printed pages can be the imprint of the gap when trimming of the printed pages are cut away. As already stated, the plate gaps can be filled with a filler material be filled in, as shown in Fig. 4, so that no There is more gap and can lead to an impression. 2u

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In this case there is also no need to cut away the impression.

In the embodiment for offset rotogravure printing shown in FIG. 6, a magnetic cylinder with a number of magnetically held printing plates 2 is inserted into the frame 52 of the printing press and rotated in the direction of the arrow by a conventional drive (not shown). Transfer cylinder 34 covered with an offset cloth 36 and a printing cylinder 38 are inserted into the frame 32 and set in rotation in the direction of the arrows by a conventional drive (not shown). Between the cloth cover J> 6 on the transfer cylinder 3 ^ and the impression cylinder 38, a material web 40, for example made of paper, is introduced.

In the offset printing according to FIG. 6, the magnetic cylinder IO with the plates 2 held on it is guided as it rotates through a dye container 42, and when the cylinder with the plates rotates past a doctor blade 44, the color is applied from the top the plates 2 scraped off. When the cylinder IO is rotated, the ink remaining in the depressions, e.g. 8, II, 12 on the plates 2 is transferred to the blanket 36 on the transfer cylinder J> k and from the blanket 36 to the printing material 40 when the printing material is on the printing cylinder 38 comes into contact with the cloth covering 36 carrying the color images.

As can best be seen from FIG Offset printing according to Fig. 6 of the cloth cover 36 on the transfer

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cylinder J4 is preferably provided with undercuts in those areas which coincide with the gaps between the plates 2 when the cloth cover J> 6 comes into contact with the plates 2 on the magnetic cylinder IO. It is therefore not necessary to fill the column with a filler material (13 according to FIG. 4) in order to prevent the column from being imprinted. As can best be seen from FIG. 7, the cloth cover J> 6 has an undercut, shown at 50, which runs transversely to the cloth cover on the transfer cylinder, and an undercut 52 which runs circumferentially. The undercut 50 can be made slightly inclined in order to adapt to the angle of the front and the following plate edges or be dimensioned sufficiently wide to effect an adaptation to the inclined plate edges during the pressing. The undercut areas 50, 52 are aligned with the plates 2 on the magnetic cylinder 10 so that when the plates 2 on the cylinder 10 come into contact with the cloth cover 36 on the printing cylinder J> K, the gaps between the plates 2 do not come into contact with the cloth cover 36 but rather are spanned by the undercuts on the cloth cover 36. Color that could be deposited, wiped into or retained in the gaps between the plates 2 is therefore not transferred to the cloth cover J> 6. This avoids any transfer of images of the gaps on the plates 2 on the magnetic cylinder 10 to the transfer cylinder J> K and the printing of images of these gaps on the printing material.

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According to the invention, the plates 2 are held on the magnetic cylinder IO by the magnetic attraction force between the cylinder IO and the base 6, each plate being held independently of other plates on the cylinder will. Plates can therefore be removed and replaced individually. Are the gaps between the panels with a filling material has been filled in, as shown at 15, when the panels are replaced, this filling material is also removed and later after a new panel is attached renewed on cylinder IO. The possibility of removing and swapping individual panels independently of other panels allows partial changes to be made to the artwork. This is especially important when printing of newspapers, magazines, periodicals and the like, from issue to issue or for distribution to different ones Districts changes in content are desired.

In the direction in which the plates 2 according to the invention are used in rotogravure printing, the front and rear edges, for example, beveled at an angle of 5 °. To get the plates to the cylinder IO with the least The beveled front and rear edges are to be able to create a distance from each other or the smallest gap arranged parallel to each other, and all panels are cut at the same angle. The panels are attached to the Side edges cut so that these edges run parallel to each other and fit into the magnetic cylinder IO in

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extend its direction of rotation. The oblique course of the front and rear edges on the plates 2 on the cylinder prevents the squeegee from being impacted if the gap moves under the squeegee as the cylinder 10 rotates. On the other hand, the squeegee could also be inclined to the; Cylinder IO arranged will. This is particularly important in the event that the gaps between the panels are not filled with a filler material are filled, as shown at 13, since this is a splash of paint and wear and tear of the squeegee is prevented. If this column is filled in, it becomes especially with a prolonged period of continued rotary printing an uneven wear of the squeegee on the printing surface avoided by the Plate surfaces and the filling material is formed.

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Claims (3)

- I6 - Claims I.) Rotogravure cylinders for use in rotogravure printing, characterized in that the cylinder is magnetic and, by magnetic attraction, a plurality of printing plates carries and holds, which abut each other with their edges and along the cylinder and around this - with the exception of the abutting edges - form an uninterrupted gravure area, whereby each of the plates has a non-compliant pad of a magnetically attractable material around the plate to hold the magnetic cylinder in a certain position, and has a surface in which Let the indentations for receiving the printing ink be molded, so that with gravure printing on the magnetic cylinder applied and held plate in the depressions printing ink deposited on an ink-receiving surface is transferred, which are printed with the image formed by the depressions on the plate surface target. 2.) Rotogravure printing cylinder according to claim I, characterized in that that the abutting edges between the panels with a non-porous, from the printing ink insoluble filler are filled. 3.) Rotogravure press for use in offset rotogravure printing pressure, characterized by a pressure cylinder 509833/0840 • - 17 - according to claim 1 or 2 and a blanket coating on the transfer cylinder which carries the transferred printing ink picks up from the plates, is held magnetically in the cylinder and has undercut areas, which on the ceiling have the same dimensions as the abutting edges of the panels on the cylinder, so that they overlay the abutting edges as the ink transfers from the panels to the ceiling. Cl / Se 5 09833/084 0