JPH027053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gravure printing plate and a method for manufacturing the same.

Recent gravure printing plates include printing plates obtained by physical engraving, mesh gravure printing plates, resin gravure printing plates, etc., but the mainstream is one obtained by corrosion using carbon tissue. This is a conventional gravure printing version.

In conventional gravure printing, as is well known, a direct plate is created by copper plating an iron cylinder, which is then silver plated to form a release layer, and then a ballad layer is formed by copper plating on top of this. First, a gravure plate material obtained by polishing the surface is prepared. To produce a gravure printing plate from this plate material, a gravure screen and continuous tone positive are printed onto a sensitized carbon film, the resulting carbon film is transferred to the surface of the plate material, and developed. ,
Furthermore, the surface of the plate material is corroded through it. After ink cells are formed by corrosion, the resist is removed to obtain a printing plate. Furthermore, in order to improve printing durability, it is common to apply chrome plating to the plate surface.

As described above, performing compensatory gravure printing requires many complicated steps to prepare a printing plate, which poses problems in terms of time and cost.

On the other hand, when revising the edition after printing is complete,
In conventional printing plates, the Ballard layer is peeled off, and a release layer is applied again using silver plating on the surface of the direct plate. Furthermore, it is necessary to apply a ballad layer of copper plating on top of that. This is also undesirable because it takes time and increases costs.

In view of the above points, an object of the present invention is to obtain a gravure printing plate that does not have the above-mentioned problems and is more advantageous than conventional printing plates in terms of plate making and plate revision. The present invention also provides a method for producing such a gravure printing plate.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 2 denotes a base material constituting the surface of the gravure cylinder, on which a pocket 3 of uniform volume is formed. Various materials can be used for the base material 2, but in the illustrated embodiment, a corrosive material that is corroded by a corrosive liquid used in the printing plate manufacturing process is used. If the corrosive liquid is a typical ferric chloride liquid, the corrosive material is copper. As described above, the base material is most preferably copper, but any metal or synthetic resin other than copper can also be used as the base material.

The pockets 3 are fine depressions uniformly distributed on the surface of the substrate, preferably in the same arrangement as the halftone dots of a gravure screen. Note that the halftone dots can be arranged in the same manner as the lithographic screen or the letterpress screen. As the gravure screen, a white line screen, a round dot screen, a contact screen, and other special point screens are applicable. These pockets 3 can be formed on the surface of the base material 2 by corrosion through a corrosion-resistant resist in which a gravure screen is baked onto the surface of the base material 2. That is, a gravure screen was baked on a carbon tissue and transferred to the smooth surface of the base material 2 to corrode the base material surface, or a photosensitive resin was applied to the cylinder surface and a gravure screen was baked on it. After that, the surface of the base material is corroded.

If the corrosion-resistant resist is hardened gelatin formed by transferring carbon tissue, and the resistance to the corrosive liquid is not absolute but only limits its penetration, it is possible to adjust the permeability of the corrosive liquid according to the continuous gradation. This allows us to print not only screens where the halftone dots and non-halftone dots are sharply black and white, such as white line screens and round dot screens, but also screens where the outline of the halftone dots is blurred, such as contact screens. It is also possible. on the other hand,
When the corrosion-resistant resist is made of a photosensitive resin film, a screen is printed in which the halftone dots and non-halftone dots are sharp.

As a corrosion-resistant resist that can adjust the permeability of the corrosive liquid according to the continuous gradation, carbon film is used. manufactured by), Rotofilm (product name,
It can also be provided by using a product manufactured by Dupont Co., Ltd.). Note that the pocket can also be made by known physical engraving, but in this case, the shape of the pocket will be different as will be described later.

The surface of the base material 2 having the pockets 3 obtained as described above is then coated with a coating layer of a non-corrosive material that is not corroded by the corrosive liquid. As a result, a non-corrosive material layer 4 is formed on the outer surface of the base material 2 and the inner surface of the pocket 3, as shown in FIG. Assuming that the corrosive liquid is a ferric chloride liquid as described above, the layer 4 is, for example, a chromium layer.
This chromium layer 4 is applied by electroplating. On the other hand, layer 4 is also required to be a wear-resistant material that does not wear out due to contact with doctors, paper, etc. during printing, and chromium also satisfies this requirement. In the case of chromium, the non-corrosive material layer 4 has a thickness of about 15 microns, for example. Note that the non-corrosive material layer 4 itself may be composed of multiple layers. In this case, at least one layer of non-corrosive material other than the inner surface of the pocket may be left in the subsequent polishing step.

Next, on the non-corrosive material layer 4, as shown in FIG. 3, an intermediate layer 5 made of a material that has good adhesion to the non-corrosive material and the corrosive material filled in the pocket is applied. be done. This intermediate layer 5 is effective when the adhesion between a non-corrosive material and a corrosive material is poor. This intermediate layer 5 is typically an electroplated layer of nickel. For the intermediate layer 5, a material is selected that has good adhesion to non-corrosive materials and corrosive materials. Nickel satisfies this condition compared to chromium as a non-corrosive material and copper as a corrosive material. The intermediate layer 5 is considerably thinner than the non-corrosive material layer 4, for example on the order of 0.1 micron in the case of nickel. Note that the intermediate layer 5 itself can also be configured with multiple layers.

After coating the non-corrosive material layer 4 and the intermediate layer 5 in the manner described above, the surface of the intermediate layer 5 is lightly polished. As a result, as shown in FIG. 4, the layer 5 on the surface is scraped away, leaving the layer 5 only on the inner wall surface of the pocket 3, and a non-corrosive material layer is formed on the surface other than where the pocket is located. 4 is exposed.

Next, a corrosive material is electroplated on the surface of the gravure cylinder in the above condition. The corrosive material in this embodiment is copper, and by electroplating the pocket is filled with copper, as shown at 6 in FIG. That is, since the intermediate layer 5 made of nickel has good adhesion to copper, the corrosive material 6 precipitates and adheres to the inner wall surface of the layer 5. On the other hand, the non-corrosive material layer 4 made of chromium and exposed in areas other than the pocket does not have very good adhesion to copper, so copper precipitates on the layer 4 as well, but does not adhere. Therefore, a state as shown in FIG. 5 is obtained.

The surface of the Guyavia cylinder thus obtained is then polished. As a result, the surface of the corrosive material 6 that was protruding above the surface is scraped off to form the same smooth surface as the non-corrosive material layer 4. As a result, the state shown in FIG. 6 is obtained.

The state shown in FIG. 6 is the state of the gravure plate material G1, in which on the surface of the plate material, countless fine corrosive parts 6 are formed between halftone dots between non-corrosive parts 4 made of non-corrosive material. They are uniformly distributed in an array, and both portions 4 and 6 form smooth surfaces.

Incidentally, among the steps of producing the gravure plate material G1 shown in FIG. 6 as described above, the step shown in FIG. 4, that is, the step of removing the intermediate layer 5 in the portion other than the pocket by polishing, may be omitted. It is possible. In this case, the corrosive material 6, ie, copper, is plated in the state shown in FIG. As a result, copper is deposited on the intermediate layer 5 in areas other than the pockets 3, but by polishing the surface, the state shown in FIG. 6 is finally obtained. In this case,
The surface of the base material can also be made smooth by polishing so as to leave the intermediate layer 5 on the surface of the base material.

In order to produce a gravure printing plate using the gravure plate material G1 shown in FIG. 6, the following steps are taken.

First, a continuous tone positive is printed on a carbon film, then transferred onto a gravure plate, developed,
Drying is performed to produce a resist 7 as shown in FIG. Next, when corrosion is performed using a corrosive liquid (in this case, a ferric chloride liquid), ink cells 9 having different depths are formed as shown in FIG. That is, the resist 7 having continuous tone positive gradation printed on the carbon film is indicated by reference numeral 8 in FIG.
Assuming that the changes are as shown in , the degree of corrosion is correspondingly large in the shadow area and deep cells 9 are formed, and the degree of corrosion is correspondingly small in the highlight area and shallow cells 9 are formed. Ru. The printing plate shown in Figure 8 obtained in this way
Since P ₁ already has a layer 4 of chromium or the like having high printing durability formed on its bank, it can be used for printing as is.

Note that, instead of the above-mentioned carbon film, a continuous tone resist such as the above-mentioned Autofilm, Chronaviur, Rotofilm (all trade names) may be used.

After printing is completed, in order to revise the printing plate, the printing plate _P1 in the state shown in FIG. 8 may be immersed in a storage tank of corrosive liquid such as ferric chloride liquid for a certain period of time. As a result, the corrosive material 6 such as copper is dissolved in the corrosive liquid, but
Since the layer 4 on the surface of the base material and the layer 4 on the inner surface of the cell are made of non-corrosive materials, they will not melt, and if the intermediate layer 5 is made of a non-corrosive material, the state shown in FIG. 4 will be obtained again. . Thereafter, the plate material shown in FIG. 6 is obtained through the state shown in FIG. 5. Further, when a material such as nickel which dissolves in a corrosive liquid is used for the intermediate layer 5, the state shown in FIG. 3 is obtained, and thereafter the plate material is obtained through the states shown in FIGS. 4 to 6.
Note that when a ferric chloride solution is used as a corrosive solution for the corrosive material copper, the nickel used as the intermediate layer is dissolved by the copper chloride produced by the reaction between copper and ferric chloride, so The state shown in FIG. 3 is obtained. Then, as shown in FIG. 7, when this plate material is corroded through the resist, a new printing plate can be obtained again.

When revising the printing plate, after cleaning the ink of the printing plate, the corrosive material 6 in the cell 9 is plated without removing it, and the plate is plated without going through the state shown in Fig. 4.
The state of the diagram may also be obtained directly. In this case, new corrosive material will be deposited on top of the old corrosive material within the cell.

FIG. 9 shows an example in which a pocket 3 is formed on a base material 2 by physical engraving. In this case, due to the nature of the physical engraving, the pocket 3 has a pointed bottom shape as shown.

10 corresponds to the situation in FIG. 5, but in this case the intermediate layer 5 coated on the non-corrosive material layer 4
Since the corrosive material 6 is plated without removing the part on the bank by polishing, the material adheres to cover the entire surface.

The entire surface is then polished and smoothed to remove the portion of the intermediate layer 5 above the bank, exposing the non-corrosive material layer 4 above the bank.
The gravure plate material G2 shown in the figure is obtained. This state corresponds to the state shown in FIG.

In this way, after the gravure plate material G2 shown in FIG. 11 is obtained, in the same way as shown in FIG.
Erosion through the resist yields the printing plate _P2 shown in FIG. 12. To revise the printing plate after printing with this printing plate _P2 , after cleaning the ink, directly plate a corrosive material such as copper. In this case, if the intermediate layer 5 is dissolved in the corrosive liquid, the intermediate layer 5 is applied again on the non-corrosive material layer 4, and then plated with a corrosive material such as copper. Alternatively, after plating the corrosive material after immersion in a corrosive liquid,
The plate material is polished to the state shown in FIG. 11.

As is clear from the above, when producing the gravure printing plate of the present invention, the step of printing a gravure screen on the carbon tissue can be omitted, and only the continuous tone positive can be printed. become. In this respect, the process is simplified and is advantageous in terms of time and cost.

On the other hand, the use of the printing plate of the present invention eliminates the need for the step of increasing printing durability by chroming the printing plate, which is required in the case of conventional gravure, and is advantageous in this respect as well.

In addition, when revising the plate, the gravure printing plate of the present invention does not require the troublesome processes of peeling off the Ballard layer, re-forming the peeling layer and the Ballard layer, unlike conventional gravure printing plates. After cleaning the ink, the only steps required are plating and polishing a corrosive material such as copper onto the printing plate. Moreover, in the present invention, in connection with this revision, the amount of copper used as a corrosive material can be significantly reduced compared to the conventional case. In the conventional case, the thickness of the copper plated on the printing plate as a Ballard layer is about 100 to 200 microns, and a corresponding amount of copper is required each time a new printing plate is manufactured and each time a new printing plate is made. In contrast, the present invention requires only a corrosive material, ie, copper, approximately equal to the total volume of the ink cells, and since the depth of each ink cell is naturally smaller than the thickness of the Ballard layer, the use of copper is unnecessary. The quantity will be less.

Further, in the present invention, an intermediate layer made of a material that has good adhesion to both the corrosive material filled in the pocket and the non-corrosive material is provided on the surface of the non-corrosive material layer on the inner surface of the pocket. This allows corrosive materials to adhere well to the inside of the pocket and prevent them from escaping.

Furthermore, in the printing plate manufacturing method of the present invention, as mentioned above, steps such as baking a gravure screen and chrome plating on the plate surface can be omitted, making it possible to use simpler steps than conventional methods, reducing time and cost. It is advantageous.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a part of the surface of a base material of a gravure cylinder used for producing a gravure plate material, and FIGS. 2 to 5 are cross-sectional views sequentially showing the steps of producing a gravure plate material. Fig. 6 is a sectional view showing the gravure plate material, Fig. 7 is a sectional view showing the corrosion process of making the printing plate of the present invention using the gravure plate material of Fig. 6, and Fig. 8 is the final result. A cross-sectional view of a printing plate according to the present invention, FIG. 9 is a cross-sectional view similar to FIG. 1 showing a gravure cylinder base material obtained by physical engraving, and FIG. 10 is a plate material using the base material of FIG. FIG. 11 is a cross-sectional view showing the final plate material obtained, and FIG. 12 is a cross-sectional view showing the state in the process of making the plate material. FIG. FIG. 2, 2a... Gravure cylinder base material, 3... Pocket, 4... Non-corrosive material layer (chromium), 5...
... Intermediate layer (nickel), 6 ... Corrosive material layer (copper), 7 ... Resist, 8 ... Continuous tone positive gradation change, 9 ... Ink cell, G1, G2 ... Gravure plate material, P ₁ ,P ₂ ...Gravure printing version.

Claims (1)

[Scope of Claims] 1 The surface of the base material has countless minute pockets recessed in the same arrangement as halftone dots, and the inner surface of these pockets and the surface portion of the base material other than the pockets include:
The pocket is coated with a layer of non-corrosive metal material that is not corroded by corrosive liquid, and an intermediate layer made of a material with good adhesion is provided on the surface of the non-corrosive metal material layer on the inner surface of the pocket. A corrosive metal material that is corroded by a corrosive liquid is filled and adhered inside, and this corrosive metal material is removed to a depth corresponding to the original gradation to be reproduced to form an ink cell with a depth corresponding to the gradation. Gravure printing plate being formed. 2. The gravure plate material according to claim 1, wherein the non-corrosive metal material is chromium. 3. The gravure plate material according to claim 1, wherein the corrosive metal material is copper. 4. The gravure plate material according to claim 1, wherein the intermediate layer is made of nickel. 5. Countless fine pockets are formed on the surface of the base material so as to be distributed in the same arrangement as halftone dots, and the inner surface of these pockets and the surface of the base material are coated with a layer of non-corrosive metal material that is not corroded by corrosive liquid. Then, the surface of the non-corrosive metal material layer on the inner surface of the pocket is coated with an intermediate layer made of a material with good adhesion, and then the pocket is filled with a corrosive metal material that is corroded by a corrosive liquid. A gravure plate material is prepared by polishing so that the non-corrosive metal material layer on the surface of the base material and the filled corrosive metal material form the same smooth surface, and on the surface of this gravure plate material,
A resist obtained by printing a continuous tone positive using a carbon film phenomenon is applied, and a corrosive liquid is applied to the surface of the gravure plate material through this resist to ink the corrosive metal material in the pocket. A method for producing a gravure printing plate, which comprises forming a gravure printing plate. 6. The method for producing a gravure printing plate according to claim 5, wherein the pocket is formed by corroding a base material through a corrosive resist on which a gravure screen is baked. 7. The gravure printing plate according to claim 5, wherein the pocket is formed by applying a photosensitive resin to the surface of the base material, baking a gravure screen thereon, and etching the resin after development. Production method. 8. The method for producing a gravure printing plate according to claim 5, wherein the pocket is formed by physical engraving. 9 After forming the non-corrosive metal material layer, the material with good adhesion is applied to the surface of the base material and the inner surface of the pocket, and the intermediate layer is formed on the inner surface of the pocket by removing the surface portion of the base material by polishing. A method for producing a gravure printing plate according to claim 5.