JPH11334235A - Printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the favorable ink transferability from cells to a matter to be printed and remove a point, from which no ink is transferred and a highlight part is seen white, by changing the shape of the cell in the highlight part. SOLUTION: The shape of a dot, in the shape of which an ink is built up for at least forming the pixel of a highlight part, consists of a triangular part, the apex and the base of a triangle of which locate to the direction of the peripheral surface of a roll, and two short straight lines extending from both the ends of the base of the triangular part towards on the extension lines of its legs and has a near V-shape gradually becoming larger in response to the degree of gradation so as to make a near V-shape. The shadowiest part has a shape spread all over with hexagonal dots. The dots except at the shadowiest part are arranged at near centers of the respective hexagons, which occupy the positions of the dots spread all over with the dots at the shadowiest part. As for a gravure printing plate, the triangular part is made deeper than the depths of the two short straight lines and of the other part due to its etching characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate (gravure plate, letterpress plate, flexographic plate or offset plate having a smooth portion having ink affinity) produced by an etching method or a laser destruction method. By improving the shape of the dots in the area, a printed matter having good dispersibility of the ink can be obtained, and in the case of intaglio printing, by improving the shape of the dots in the light area, the ink from the cells to the print medium can be obtained. The present invention relates to a printing plate capable of obtaining a printed matter which has good transferability and eliminates points at which ink in which a light portion appears as white is not transferred.

[0002]

2. Description of the Related Art The dispersibility of ink is a function of the size of an area of one dot for obtaining its gradation, the thickness of the ink, and the fact that the ink is transferred uniformly over the entire area of the dot. Depends on the relationship. Even if the area of the dot is small, if the thickness of the ink is transferred, the gray scale becomes unnatural. Further, in a heaping state in which the ink does not transfer evenly even when the area of the dot is large and the center is high, the dispersibility of the ink with respect to the size of the dot is poor, and the gradation of light and shade is also poor. Further, when the transferred ink amount and the dot area are the same, the round dot shape has poor dispersibility of the ink as compared with the elongated dot shape. On the other hand, an elongated dot shape may cause moire. FIG. 4 shows the shape of a cell of a conventional gravure printing plate obtained by engraving a diamond needle of an electronic engraving machine (heliocrissograph). Since the cell depth is shallow and the cell width is large, the surface tension of the ink in the cell acts small and the transferability of the ink is good, but the transferred ink is heaped and not smooth, so the dispersibility of the ink with respect to the size of the dot is low. It is bad, and the gradation is also bad. FIG. 5 shows the shape of a cell of a conventional general gravure printing plate obtained by an etching method. The cell is a round hole or a rectangular cell, and the cell at the most shadow portion lacks the vicinity of the intersection of the screen lines. Thus, a free flow cell having an increased porosity can be obtained. However, since the depth of the contour portion of the cell is deep and the cell width is small, the surface tension of the ink on the wall surface of the hole in the cell acts in the light portion, and the ink transferability is inferior to that of the cell in FIG. There are a lot of points that can be seen. Although not shown, the gravure printing plate according to Japanese Patent Application No. 6-28991 filed by the applicant of the present application is a gravure printing plate obtained by an etching method, and the shape of the cell of the light portion is perpendicular to the doctor contact line. This is a long, long-hole cell, and the ink inside the cell is less likely to be scraped off by a doctor, making it difficult to cause hollowing out (non-transfer of ink at the center of the cell). In this case, the surface tension of the ink acts greatly, and the transferability of the ink is inferior, and moire tends to occur. Therefore, it is essential to eliminate moire as disclosed in Japanese Patent Application Nos. 6-124628 and 6-150390. . Although not shown, the gravure printing plate according to Japanese Patent Application No. 7-216714 filed by the applicant of the present application is a round or square cell similar to the cell of FIG. It is dispersed so that if the cells are in good distribution and the etching distribution is excellent, the gray scale is excellent, but the etching management is difficult because the cells are not opened or the cells are connected. As in FIG. 5, the surface tension of the ink in the cell acts greatly, and the transferability of the ink is inferior. On the other hand, in the relief printing plate and the planographic printing plate, the shape of the dots on which the ink of the light portion is provided is substantially circular, which substantially corresponds to FIG.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a printing plate manufactured by an etching method or a laser destruction method, wherein the dispersibility of ink is improved by improving the shape of dots in a light portion or a halftone portion. Good printed matter is obtained,
Furthermore, in the case of intaglio printing, it is necessary to provide a printing plate in which the transferability of the ink from the cells to the printing material is good, and the printed material is obtained in which the point where the ink which appears in the light portion as white is not transferred has been eliminated. It is an object.

[0004]

The present invention is a printing plate manufactured by etching or laser destruction, in which dots on which ink of the pixels is provided are concave portions, convex portions, or smooth portions having ink affinity. The vertices and the base of the triangle are oriented in the roll circumferential direction so that the dots on which the ink for forming pixels is formed with respect to the dots of the light portion form a substantially V-shape that gradually increases in accordance with the gradation. , And two short straight lines extending from both ends of the bottom of the triangle on the oblique line. Also,
In the present invention, the most shadow portion is a shape in which hexagonal dots are spread, and dots other than the most shadow portion are arranged so as to be located substantially at the center of each hexagon when the dots in the most shadow portion are spread. A printing plate is provided.

[0005]

FIG. 1 shows a first embodiment in which the printing plate of the present invention is applied to a gravure printing plate. This gravure printing plate has hexagonal dots (cells) in the most shadow portion (without limitation, for example, an aperture ratio of 80%).
It is a shape laid. Then, dots of a size other than the shadow portion are arranged in a regular oblique line so as to be located at the center of each hexagon when the dots of the shadow portion are spread. The vertices and bases of the triangles extend in the roll circumferential direction so that the cells in the light portion having a gray scale of more than 0% to 16% or less form a substantially V-shape that gradually increases in accordance with the gray scale. It is composed of a triangular portion located and two short straight line portions extending on both sides of the oblique side from both ends of the base of the triangular portion. Since the triangular portion has a large area and a large width, the triangular portion is etched deeper than the other portions of the two short straight lines due to the etching characteristics. When the gray scale is 25%, the cell has a substantially triangular shape, not shown, and the gray scale is more than 16% to 25.
When a cell of a light portion or a halftone portion of less than 10% is provided, the shape is changed gradually from a substantially V-shaped cell at 16% to a substantially triangular cell at 25%.
A cell having a gray scale of 35% is approximately hexagonal, and a cell (not shown) of a halftone portion having a gray scale of more than 25% to less than 35% is generally triangular when 25% is provided. From a cell of 35% to a substantially hexagonal cell at 35%. Shade gradient is over 35% to 8
The cells in the halftone or shadow portion of less than 0% have a substantially hexagonal shape that gradually increases in size while maintaining a substantially similar shape so as to correspond to the gray scale. In this gravure printing plate, the depth is shallow at two short straight lines and deep at the triangular portion. The releasability of the ink from the cells increases as the cells are deeper. This is considered to be due to an increase in the adsorbing power of the ink to the cell side wall. Thus, the ink releasability at the two short straight lines is good, and the two short straight lines have good ink transferability because the surface tension at the shallow depth is kept small. is there. If this printing plate is not a gravure printing plate, but a flexographic plate or offset plate having a relief portion or a smooth portion having ink affinity,
Since the dots are not composed of cells, there is no relationship with the depth of the cells. However, cells having a gradation gradient of more than 0% to 16% extend from a triangular portion in which the vertex and the base of the triangle are located in the roll circumferential direction, and extend on both sides of the base of the triangular portion on the oblique side extension line. Since it has a substantially V-shape composed of two short straight lines, the distance from the end of the dot to the end is larger than that of the cells in FIGS. There is a higher cure. As an example, 10
A one-part liquid with high sensitivity that can be hardened by a weak laser beam such as an argon / neon gas laser beam after the plate to be made, which is plated with ballad copper to about 0 microns, is mirror-polished and surface activated. A photosensitive resin is applied and dried to form a photosensitive resin film having a thickness of 3 μm. Then, the laser beam is main-scanned on the photosensitive resin film in a direction perpendicular to a doctor plate surface contact line, and the laser beam is irradiated. After writing negative printing information on the photosensitive resin film by performing sub-scanning so that adjacent irradiated lines on the plate overlap and shift, and performing flashing irradiation of a laser beam according to the printing information, development is performed. After dissolving the unexposed part of the photosensitive resin film, the resist is heated and cured, and then etched to engrave positive printing information on the plate surface in dots. Resist peeled was chromium plated for applying printing durability, the printing of the light section is ink printed material appears white point without metastasis lost the equivalent cell shown in FIG. 4 were obtained. Further, the dispersibility of the ink was improved as compared with the cell shown in FIG. FIG. 2 is an embodiment when the printing plate of the present invention is a gravure printing plate,
80% of the cells in the shadow region are intermittent at or near the intersection of the screen lines to form free flow cells. (A) has one dot formed by a hexagonal screen line defining one dot dispersedly and defines six dots around a dot which is not broken by the screen line. The screen is partially broken. In (b) and (c), the screen lines forming the dots are partially cut for all the dots. In (b), the screen lines forming the dots are divided in a “Z” shape and dispersed differently in three directions, and (c), the screen lines forming the dots are divided in a “Y” shape. When a free flow cell is used,
When the ink is filled in the cells by scratching the ink with a doctor, bubbles can be prevented from remaining in the cells due to the flow of the ink, so that the ink transferability is good.

FIG. 2 shows a second embodiment in which the printing plate of the present invention is applied to a gravure printing plate. The gravure printing plate has a shape in which the most shadow portion (for example, but not limited to, an aperture ratio of 80%) is formed by laying square dots (cells). Then, dots having a size other than the shadow portion are arranged in a regular array so as to be located at the center of each square when the dots of the shadow portion are spread. The vertices and bases of the triangles extend in the roll circumferential direction so that the cells in the light portion having a gray scale of more than 0% to 16% or less form a substantially V-shape that gradually increases in accordance with the gray scale. It is composed of a triangular portion located and two short straight line portions extending on both sides of the oblique side from both ends of the base of the triangular portion. This is the same as the first embodiment. When the gray scale is 25%, the cell has a substantially triangular shape, not shown, and the gray scale is 16%.
When cells of a light portion or a halftone portion of less than 25% or more are provided, 25% of cells in the approximate V shape at 16% are used.
The shape is such that the cell gradually changes into a substantially triangular cell at%. This is the same as the first embodiment. A cell having a gray scale of 35% is approximately hexagonal, and a cell (not shown) of a halftone portion having a gray scale of more than 25% to less than 35% is generally triangular when 25% is provided. From a cell of 35% to a substantially hexagonal cell at 35%. This is the same as the first embodiment. The cells of the halftone or shadow portion having a gray scale of more than 35% to less than 80% have a substantially square shape which is substantially similar and gradually increases in size to correspond to the gray scale.

When the printing plate of the present invention is applied not only to a gravure printing plate but also to a relief plate and a flexographic plate or offset plate having a smooth portion having ink affinity, the transferability of the ink is good and the gradation of light and shade can be improved. . The printing plate of the present invention includes not only a roll printing plate but also a lithographic plate. Furthermore, the present invention is a plate making method described in the above embodiment,
The method is not limited to the method of forming a resist image by laser exposure / development and subsequent etching, but the surface of the roll is formed of a hard plastic film such as an epoxy resin containing a magnetic powder and directly applied with a high-power laser such as a yag laser. Also includes gravure printing plates engraved with cells.

[0008]

As described above, the printing plate of the present invention is a gravure plate, a relief plate manufactured by an etching method or a laser destruction method, and a flexographic plate or an offset plate having a smooth portion having ink affinity. In addition, since the shape of the dots in the light portion was formed substantially in a V-shape, a printed material having good dispersibility of the ink in the light portion was obtained. Further, according to the printing plate of the present invention, a printing plate manufactured by an etching method or a laser destruction method, in particular, an intaglio (gravure printing plate), the shape of the dots in the light portion is improved so that the printing from the cell to the printing object can be performed. The printed matter has good ink transferability and eliminates the points where the ink is not transferred where the light portion appears white. That is, according to the gravure printing plate according to the present invention, as in the cell shape of the light portion of the conventional gravure printing plate obtained by engraving the diamond needle of the electronic engraving machine shown in FIG. Since the cell depth is deep and the cell depth extends shallowly in all directions, the surface tension of the ink on the side wall surface in the cell can be kept small, and the ink transferability is good. And the printed matter of the light portion was obtained in which the point where the printing of the light portion appeared white without transfer of the ink was eliminated as in the cell shown in FIG. In addition, the dispersibility of the ink was improved as compared with the cells shown in FIGS. Further, the printing plate of the present invention has no moiré.

[Brief description of the drawings]

FIG. 1 is a diagram showing the shape of a dot (cell: a white area) corresponding to a gray scale according to the first embodiment when a printing plate of the present invention is a gravure printing plate.

FIG. 2 is an embodiment in which the printing plate of the present invention is a gravure printing plate, and 80% of the cells at the most shadow portion are intermittent at the intersection of the screen lines or in the vicinity thereof to be free flow cells. The figure which shows the shape of a dot (cell: white area / screen line: black).

FIG. 3 is a diagram showing the shape of dots (cells: white areas) corresponding to the gray scale in the second embodiment when the printing plate of the present invention is a gravure printing plate.

FIG. 4 is a view showing a cell shape of a light portion of a conventional gravure printing plate obtained by engraving a diamond needle of an electronic engraving machine.

FIG. 5 is a diagram showing the shape of a cell in a light portion of a conventional general gravure printing plate obtained by an etching method.

Claims (2)

[Claims] 1. A printing plate manufactured by an etching method or a laser destruction method, wherein a dot on which ink of a pixel is provided is a concave portion, a convex portion, or a smooth portion having ink affinity, and a pixel relating to a dot of a light portion. A triangular portion in which the vertices and the base of the triangle are located in the roll circumferential direction so as to form a dot in which the ink for forming the ink is formed into a roughly V-shape that gradually increases in accordance with the gray scale; A printing plate comprising: two short straight lines extending from both ends of the base of the triangle to the extension of the hypotenuse. 2. A shape in which a hexagonal dot is spread over the most shadow portion, and dots other than the most shadow portion are arranged so as to be located substantially at the center of each hexagon when the dot of the most shadow portion is spread. The printing plate according to claim 1, wherein