JP2006044206A - Method for making gravure printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for making a gravure printing plate which can form cells by forming a sharp positive image by coating to a roll out of which a printing plate is made, using an inkjet printer and thus, can form a high definition printing plate at a low cost. <P>SOLUTION: In this method, an undercoat film which is soluble in water, photosensitive by ultraviolet light and ink-acceptive, is formed on a roll out of which a printing plate for gravure printing is made with a copper sulfate-plated surface mirror-treated and further, cleaned. Next, a positive image of a colored ink which is of an ultraviolet-proofing nature and soluble in water, is formed using the inkjet printer. After that, the portion not superposed by the positive image of the undercoat film, is made insoluble in water by exposing the whole roll to the ultraviolet light, then the undercoat film of the positive image and the portion superposed by the positive image, are removed by water-washing, and the copper sulfate plating-exposed surface of the positive image is etched using a cupric chloride solution or a ferric chloride solution to form the cells. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for making a gravure plate, in which cells can be formed by coating and forming a clear positive image on a plate-making roll using an ink jet printer, and a high-definition plate can be formed at low cost.

The method of engraving cells with an electronic engraving machine to make a gravure plate is environmentally friendly and does not use a photosensitizer, developer, or resist stripper. Inferior. The method of making a gravure plate by photolithography has many processing steps, increases the equipment, increases the equipment cost, and the running cost of the photosensitive agent, developer, and resist stripping solution is high.
In view of this, a method for making a gravure plate by an ink jet printer in which the equipment is much cheaper than an electronic engraving device or a laser exposure device has been proposed.
The method of making a gravure plate by a conventional ink jet printer is to rotate the plate making roll horizontally by chucking both ends of the ink jet printer, moving the ink jet nozzle close to one end, and scanning and moving to the other end while jetting etching resist. A negative image is directly formed by this, and then the roll is removed from the ink jet printer and set in a corrosive apparatus to etch the cells.
Japanese Patent Laid-Open No. 2002-096441

In order to obtain a high-definition image, the practical use of an ink jet nozzle capable of ejecting droplets of 1 picoliter level is awaited, and the success of ink jet of 1 / picoliter droplets has been announced, 1 picoliter-class droplet ink jet has been put into practical use without waiting for several years.
The method of making a gravure plate with an ink jet printer disclosed in Japanese Patent Application Laid-Open No. 2002-096441 is intended to directly form a negative image on a copper sulfate plating surface by ejecting ink from an ink jet nozzle onto a plate making roll. Will not be absorbed and the negative image will blur. In particular, with an inkjet that ejects droplets of 1 picoliter class, the surface of the roll has a surface roughness that causes ink to squeeze into the recesses of the surface roughness and spread to form a clear negative image. It is easily predicted that it will be difficult to do.

  The present invention has been devised in view of the above-described points, and a cell can be formed by coating and forming a clear positive image on a plate-making roll by an ink jet printer, thereby forming a high-definition plate at low cost. It is possible to provide a gravure plate making method.

  In the present invention, an undercoat film that is soluble in water, UV-sensitive, and ink-receptive is applied to a gravure printing plate roll that has been subjected to a mirror-finished copper sulfate plating surface and further cleaned. After film formation, a positive image of colored ink having ultraviolet light shielding properties and water solubility was formed by an ink jet printer, and then the entire surface of the plate-making roll was exposed to ultraviolet light to cover the positive image of the undercoat film. Next, the unexposed portion is made insoluble in water, and then washed out with water to remove the positive image and the undercoat film on the portion where the positive image is covered, and then the exposed surface of the positive image on the copper sulfate plating is covered with the second chloride. An object of the present invention is to provide a gravure plate making method characterized in that a cell is formed by etching using a copper solution or a ferric chloride solution.

According to the plate making method of the gravure plate of the present invention, an undercoat film that is soluble in water and has ultraviolet sensitivity and ink receptivity is formed on the plate making roll, and then the ultraviolet ray is blocked by an inkjet printer. The positive image of the colored ink having water solubility is formed, so that the positive image can be clearly formed, and then the plate-making roll is exposed to the whole surface with ultraviolet rays so that the positive image of the undercoat film is not covered. Since the part is insoluble in water and then developed with water to dissolve and remove the part of the undercoat film that covers the positive image, the exposed surface of the copper sulfate plating can be formed very clearly. A cell formed by etching has a very sharp high-definition outline, and thus a high-definition gravure plate can be made.
According to the gravure plate making method of the present invention, a negative image is formed by forming a positive image with an ink jet printer and further removing the positive image portion by water development, so when forming a negative mask with an ink jet printer. In comparison, because of the difference in resolution between the formation of a positive image and the formation of a negative image, the former is more advantageous in relation to the ultimate ejection amount of the inkjet nozzle because the image definition is further increased.
According to the method for making a gravure plate of the present invention, water development is possible, so that the cost of processing the development waste liquid is not bulky and contributes to the preservation of the global environment.
According to the method of making a gravure plate of the present invention, a positive image made of an etching resist is applied to a plate-making roll by a printer with respect to a plate-making roll of various sizes, which does not belong to any conventional method of making a gravure plate. It can be formed satisfactorily, and after forming a positive image, a negative mask can be formed by developing with water, and then a cell can be formed by etching. In addition, compared to the conventional photosensitive film coating-laser exposure-development-corrosion process, the apparatus cost can be greatly reduced, and further, an undercoat film having no photosensitivity is formed and ultraviolet light shielding property is formed thereon. Since a positive image of colored ink that is soluble in water is formed by ink jetting, there is no problem of residue, and work can be performed in a bright room.

An embodiment relating to a gravure plate making method of the present invention will be described with reference to FIG.
FIG. 1 shows a process diagram of a gravure plate making method.
The present invention provides a roll for gravure printing in which a copper sulfate plating surface is mirror-finished to further clean the surface, a roll coater, an ink jet printer, a washing device, a corrosion device, a resist removing device, and a chromium plating device. To make a plate.
The plate making roll for gravure printing in which the copper sulfate plating surface is further mirror-finished to further clean the surface includes both a direct plate type roll and a ballad type roll.
In the gravure plate making method of the present invention, first, a plate making roll is set on a roll coater to form an undercoat film. This undercoat film uses a liquid agent that is soluble in water, UV-sensitive, and ink-receptive, and is a liquid agent that becomes a water-soluble fusoxo material manufactured by Toyobo Co., Ltd. = Cosmolite (registered trademark) ) Can be used.
Specific examples of the material include photosensitive resin compositions described in JP-A Nos. 05-249668 and 06-0667426. The former is mainly composed of a phase (A) mainly composed of a hydrophobic polymer having a Shore A hardness of 20 ° to 70 ° and a hydrophilic polymer having a Shore A hardness of 20 ° to 90 ° as a dispersed phase. Light having a phase (B), except that the shore A hardness of the phase (A) and the phase (B) is different from each other, while the shore A hardness is 20 ° to 90 ° by photopolymerization as a continuous phase. A photosensitive resin composition comprising a polymerizable compound, the latter comprising a photosensitive resin plate having a photosensitive resin layer for water-developable flexographic printing provided on a substrate via an adhesive layer A mixture wherein the adhesive layer comprises 90 to 50% by weight of a copolyester having a glass transition temperature of 10 ° C. or lower, and 10 to 50% by weight of a copolyester having a glass transition temperature of 50 ° C. or higher; Polyfunctional isocyanates, hydroxyl groups and acryloyl A photosensitive resin plate material characterized by comprising a composition containing a compound having a group or a methacryloyl group.
The photosensitive resin plate material is applied to the entire surface of the roll so as to have a thickness of, for example, 2 to 3 μm and dried.
Without forming the undercoat film on the plate-making roll, it is conceivable to apply and form a negative image directly by setting the plate-making roll on the ink jet printer.
Even if mirror polishing is performed very well and the surface is cleaned, the surface tension of the copper sulfate plating surface against the ink is not optimal, and the surface roughness of the roll causes the ink to be in the recesses of the surface roughness. This is because it is assumed that it will be swollen and spread due to capillary action, and it will be difficult to apply and form a clear negative image.
The roll coater can employ either a spiral coating method or a dipping coating method. In a spiral coater type roll coater, for example, a plate-making roll is horizontally chucked at both ends and rotated at a constant rotation speed, and then lifted toward the lower edge of one end of the plate-making roll to form a helical gear-shaped coating roll. The coating roll is moved to the other end of the plate-making roll while the coating roll is non-contactingly rotated to apply the cosmolite solution in the tank to the plate-making roll. Is formed by coating and drying. In the dipping coating type roll coater, the plate-making roll is set up and chucked at both ends at the top and bottom, and a donut dish is fitted on the upper end of the roll without applying rotation, and the cosmolite solution is stored in the donut dish. The donut plate is applied to the entire circumference of the plate making roll and dried to solidify by lowering the donut plate to the lower end of the roll at a constant speed so that the entire circumference of the roll donut plate fitting part can be applied. To do.
Next, the plate-making roll is set in an ink jet printer, and a positive image is printed by ejecting colored ink (preferably black ink) having ultraviolet light shielding properties and water solubility on the undercoat film. As this colored ink, an aqueous ink for an ink jet printer can be used. Since the ink needs to have ultraviolet light shielding properties, it is preferable to use a pigment ink. In particular, for a fine nozzle capable of ejecting 1 picoliter, it is important to select and develop ink that does not cause passage blockage.
The printing of the positive image will be described in detail. The plate making roll is horizontally chucked at both ends by a pair of chuck / rotation driving means provided in the ink jet printer and rotated at a constant rotational speed, and provided on a two-dimensional table. The inkjet nozzle is moved close to the side edge at one end of the plate-making roll and stopped in proximity, and ink is ejected from the inkjet nozzle while scanning and moving the inkjet nozzle in the plate-making roll surface length direction to print a positive image. When the positive image is printed, a lamp having a length corresponding to the entire length of the roll is turned on to expose the entire surface so that the portion not covered with the positive image of the ink is insoluble in water.
Next, the plate-making roll is set in a washing device and developed with water. More specifically, the plate making roll is chucked horizontally at both ends by a pair of chuck / rotation driving means provided in the washing device, rotated at a constant rotation speed, and sprayed with water to remove the portion where the positive image is covered. Since the undercoat film is not exposed to ultraviolet light, it is soluble in water and the positive image is also soluble. Therefore, the portion covered with the positive image is dissolved by water development, and the copper sulfate plating surface of the positive image is exposed. The undercoat film not covered with the positive image is cured by ultraviolet rays, becomes insoluble in water, and remains as an etching resist. As water used for water development, tap water can be used, but development with warm water to which a small amount of an activator is added: 40 ° C. is favorably performed.
Next, the plate-making roll is set in a corrosion apparatus to corrode the exposed surface of the copper sulfate plating of the positive image to etch the cells. Specifically, the plate-making roll is horizontally chucked at both ends by a pair of chuck / rotation driving means provided in the corrosion apparatus, rotated at a constant rotational speed, immersed in a cupric chloride solution or a ferric chloride solution, and A cell is etched by chemically corroding the exposed surface of the copper sulfate plating.
Next, the plate making roll is set in a resist removing device, and the negative resist image is dissolved and removed with a strong alkali of PH 10.0 to PH 11.0. The tank for storing the strong alkali solution in the resist removing apparatus is lowered and the lid is closed, and then the roll surface is neutralized and washed with acid and further washed with neutral water.
Next, the plate making roll is set in a chrome plating apparatus, and chrome plating is applied so that the plating thickness is 7 to 8 μm.
Finally, the plate surface is self-lubricated by graining with sandpaper.

The process drawing of the plate-making method of the gravure plate which concerns on embodiment of this invention is shown.

Claims (1)

Forming an undercoat film that is soluble in water and has ultraviolet sensitivity and ink receptivity, on a plate-making roll for gravure printing that has been further mirror-treated on a copper sulfate plated surface, Next, a positive image of colored ink having ultraviolet light shielding properties and water solubility is formed by an ink jet printer, and then the whole surface of the undercoat film not covered with the positive image is exposed by exposing the entire surface of the plate-making roll with water. Next, washing out with water to remove the positive image and the portion of the undercoat film covered by the positive image, and then exposing the exposed surface of the positive image to the copper sulfate plating on the cupric chloride solution or chloride. A method for making a gravure plate, wherein a cell is formed by etching using a ferric solution.

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