JPH11235880A - Printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a printed matter having a good dispersiveness of ink by forming a printing plate by selecting one or more kinds of dots in the form of one or more pieces of radial rectangular extended from an X shape, Y shape or a circle at frontal view, and making them large gradually so as to correspond with the gray level gradation. SOLUTION: A gravure printing plate is formed in a shape in which cells of the light part of gray level gradation of 3-35% or an intermediate tone part is superimposed on the center of an X shape in the circle, and they are formed large gradually maintaining its approximate similarity until it reaches the position near the screen line of a shadow so as to correspond with the gray level gradation. Cells in the intermediate part or shadow part of a gray level gradation of 35-64% are formed by changing gradually so that they approach a rectangular cell shape of the 64% shadow part. In addition, cells in the shadow part of a gray level gradation of 75-80% is formed by raising the numerical aperture step by step so that the screen line becomes thin, and then cells in the shadow part of a gray level gradation of 80% are made free flow cells by making the screen line intermittent in its intersection.

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 an ink is determined by the correlation between 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. . Even if the area of the dot is small, if the thickness of the ink is transferred, the gray scale becomes unnatural. Also,
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. 5 shows a cell shape of a conventional gravure printing plate obtained by engraving a diamond needle of an electronic engraving machine. The central portion is a diamond cell having a deepest pyramidal hole, and the cell has a shallow cell depth. Since the width is large, the surface tension of the ink in the cell acts small and the ink transferability 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 poor, and the gradation gradation is also high. become worse. FIG. 6 shows the shape of a cell of a conventional general gravure printing plate obtained by an etching method. The cell is a round hole cell, and the cell in the shadow portion can be a free flow cell. However, since 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 is large in the light portion, so that 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 elongated in a direction perpendicular to the doctor contact line. This is a perforated cell. The ink inside the cell is not scraped off by a doctor, so it is unlikely to drop out (non-transfer of ink at the center of the cell). It has a large effect and the transferability of the ink is inferior to that of the cell of FIG. 5, and moire is more likely to occur than the cells of FIG. 5 and FIG.
It is indispensable to eliminate moiré as disclosed in Japanese Patent Application No. 4628 and Japanese Patent Application No. 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 hole cell similar to the cell in FIG. 6 and is dispersed so as to have an opening ratio from a light portion to a shadow portion. If the etching control is performed well and a cell in a completely distributed state is formed, the gray scale is excellent, but the etching control is difficult, for example, the cells are not opened or the cells are connected, and similar to FIG. In addition, the surface tension of the ink in the cell greatly affects the transferability of the ink. On the other hand, even in letterpress and planographic printing, the shape of the dots where
Since it was a substantially circular shape substantially corresponding to FIG. 6, the dispersibility of the ink was poor.

[0003]

SUMMARY 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 light part, a printed matter having good ink dispersibility can be obtained. In the case of intaglio printing, the shape of the dots in the light part can be improved to improve the shape of the dots in the cell. It is an object of the present invention to provide a printing plate from which a printed matter having good ink transferability and free from points where the light portion looks white and the ink is not transferred is obtained.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a printing plate in which pixels are manufactured by an etching method or a laser destruction method. And the shape of the dot as viewed from the front is X-shaped, or Y-shaped, or at least one type of shape obtained by extending at least one radial short line from a circle is selected. It is an object of the present invention to provide a printing plate characterized in that the printing plate is formed to have a correspondingly larger size.

[0005]

FIG. 1 shows a gravure printing plate according to a first embodiment of the present invention. This gravure printing plate has cells in a light portion or a halftone portion with a gradation gradation of 3% to 35%,
It is formed in a shape in which a circle is superimposed on the center of the X-shape, and maintains a similar shape until it reaches a position near the screen line of the shadow portion so as to correspond to the gray scale, and gradually increases in size. Then, the cells of the halftone portion or the shadow portion having a gradation gradient of more than 35% to less than 64% are gradually changed so as to approach a square cell shape of a shadow portion of 64%. % To less than 75% are formed by gradually changing the cells of the shadow portion so as to approach the rectangular cell shape of the 75% shadow portion.
Cells having shadow portions of less than 0% are formed by gradually increasing the aperture ratio so that the screen lines become thinner, and the gradation of gradation is 80%.
The cell of the shadow portion was interrupted at the intersection of the screen lines or in the vicinity thereof to form a free flow cell. In this gravure printing plate, since the cells in the light portion are formed in an X shape, the dispersibility of the ink is higher than that of the round-hole cells, and the depth at the intersection of the cells is large and the gravure printing plate deviates from the intersection. Etching is performed so that the depth becomes shallow at places where the surface tension is small at portions where the depth is off the intersection of the cells. This has an effect on the intersections of the cells, so that the ink transferability is good as a whole. As an example, 1
After the surface to be plated, which is plated with ballad copper to around 00 microns, is ground or buffed and surface activated,
A photosensitive resin film having high sensitivity that can be cured by a weak laser beam such as an argon / neon gas laser beam is applied to a thickness of 5 to 8 microns to form a coating, and a coating for preventing the photosensitive resin film from being oxidized. Then, the laser beam is main-scanned on the photosensitive resin film in a direction orthogonal to the doctor plate surface contact line, and the sub-scan is performed such that adjacent irradiated lines on the plate surface of the laser beam overlap and shift. After writing negative print information on the photosensitive resin film by flashing and irradiating the laser beam according to the print information, developing and dissolving the unexposed part of the photosensitive resin film, the resist After heating and curing, the plate is etched to engrave positive printing information on the plate surface in dots, and the chrome Were key, print the light section is a point that appears white without ink transfer printed material lost equivalent to the cell shown in FIG. 5 were obtained. Further, the dispersibility of the ink was improved as compared with the cell shown in FIG.

FIG. 2 shows a gravure printing plate according to a second embodiment of the present invention. In this gravure printing plate, the cells of the light portion having a gradation gradation of 3% to 6% are formed in a shape in which one radial short line is extended from a circle, that is, a so-called keyhole shape, and are adapted to the gradation gradation. The cell of the light part having a gradation gradient of more than 6% to less than 16% is formed into a so-called φ shape in which two radial short lines are extended from both sides on both sides. And a cell of a light portion or a halftone portion having a gray scale of more than 6% to 49% is formed by maintaining a similar shape so as to correspond to the gray scale.
Formed with a round shape superimposed on the center of the shape, with a gradation of 49%
Super to less than 64% of cells in the halftone or shadow area
The cell is formed by gradually changing the shape so as to gradually approach the cell of the shadow portion of 64%, and the cell of the shadow portion having the gradation of 64% to less than 80% is gradually increased in the opening ratio so that the screen line becomes thin. The cells in the shadow area having a gray scale of 80% were intermittently intersected at the intersection of the screen lines or in the vicinity thereof to form free flow cells. This gravure printing plate is formed from a circular shape to a shape having at least one radial short line portion, particularly as a shape of a cell of a light portion, and is selected differently in the size of a dot. The ink dispersibility is higher than that of a porous cell, and the depth at the intersection of the cells is so large that it is etched away from the intersection, so that the depth becomes shallower. However, the good transferability of the ink where the surface tension is small in the shallow portion affects the intersection of the cells where the transferability of the ink is inferior because the depth is deep, so that the transferability of the ink as a whole is good.

FIG. 3 shows a third embodiment of the gravure printing plate of the present invention. In this gravure printing plate, cells of a light portion or a halftone portion having a gradation gradation of 3% to 25% are formed by +
It is formed in a shape in which a round shape is superimposed on the center of the shape, and is gradually formed to have a similar shape until it reaches the position of the screen line so as to correspond to the gradation gradation.
The cells of less than 75% of the halftone portion or the shadow portion are maintained until the round portion reaches the position of the screen line so as to correspond to the gray scale while maintaining the shape in which the circle is superimposed on the center of the + shape. Formed gradually in a similar fashion, with 74% gradation
A cell having a shadow portion of less than .about.80% is formed into a square with rounded corners, and the porosity is gradually increased until the screen lines have a predetermined thickness so as to correspond to the gray scale. 80% of the cells in the shadow area were intermittently intersected at the intersection of the screen lines or in the vicinity thereof, thereby forming free flow cells. This gravure printing plate, in particular, has a shape in which the cells of the light part are formed by superimposing a round shape at the center of the + shape, and gradually becomes almost similar until it reaches the position of the screen line so as to correspond to the gray scale. Because it is formed large, the dispersibility of the ink is higher than that of the conventional round-hole type cell, and the etching is performed so that the depth at the intersection of the cells is large and the depth outside the intersection is small. Therefore, the good surface transferability of the ink where the surface tension is small at the shallow part outside the cell intersection affects the intersection of the cell where the ink transferability is poor due to the deep depth. The transferability of the ink is good.

FIG. 4 shows a gravure printing plate according to a fourth embodiment of the present invention. In this gravure printing plate, cells of a light portion having a gray scale of 3% to 25% are formed in a shape in which a circle is superimposed on the center of a Y-shape, and are positioned at screen lines so as to correspond to the gray scale. Until it reaches a similar shape, it gradually grows larger, and the cells of the light part or the halftone part with more than 25% to 49% of gray scale are formed in the shape of the + part and the round part overlapping the center of the + part. And a cell of a halftone portion or a shadow portion having a grayscale gradient of more than 49% to less than 74% is formed to have a similar shape gradually larger until reaching the position of the screen line so as to correspond to the grayscale gradient. While maintaining the shape in which the round shape is superimposed on the center of the + shape, the round portion is gradually increased to a substantially similar shape so as to correspond to the gray scale until reaching the position of the screen line, and the gray scale is 74% Form cells with less than 80% of shadows in rounded corners In addition, the porosity is gradually increased until the screen lines have a predetermined thickness so as to correspond to the gray scale, and the cells of the shadow portion having the gray scale of 80% are formed at or near the intersections of the screen lines. Was interrupted to obtain a free flow cell. In this gravure printing plate, the cells in the light part are formed in a shape in which a round shape is superimposed on the center of the Y shape, and gradually become almost similar until reaching the position of the screen line so as to correspond to the gray scale. Because it is formed large, the dispersibility of the ink is higher than that of the conventional round-hole type cell, and the etching is performed so that the depth at the intersection of the cells is large and the depth outside the intersection is small. Therefore, the good surface transferability of the ink where the surface tension is small at the shallow part outside the cell intersection affects the intersection of the cell where the ink transferability is poor due to the deep depth. The transferability of the ink is good.

When the printing plate of the present invention is applied to not only a gravure printing plate but also a flexographic plate or an offset plate having a relief portion and a smooth portion having ink affinity, the transferability of 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.

[0010]

As described above, the printing plate of the present invention, a printing plate manufactured by an etching method or a laser destruction method (a gravure plate, a relief plate, and a flexographic plate or offset having a smooth portion having ink affinity). According to the plate, a printed matter having good ink dispersibility can be obtained by improving the shape of the dots in the light portion. 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. The printed matter obtained was excellent in dispersibility, and the point where the printing in the light part appeared white without transferring the ink was equivalent to the cell shown in FIG. Further, the dispersibility of the ink was improved as compared with the cells shown in FIGS. Further, the printing plate of the present invention is
Moire does not occur.

[Brief description of the drawings]

FIG. 1 is a view showing a shape of a dot (cell) corresponding to a gray scale, showing a first embodiment of a gravure printing plate of the present invention.

FIG. 2 is a view showing a shape of a dot (cell) corresponding to a gray scale according to a second embodiment of the gravure printing plate of the present invention.

FIG. 3 is a view showing a shape of a dot (cell) corresponding to a gray scale according to a third embodiment of the gravure printing plate of the present invention.

FIG. 4 is a view showing a shape of a dot (cell) corresponding to a gray scale according to a fourth embodiment of the gravure printing plate of the present invention.

FIG. 5 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. 6 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 (1)

[Claims] 1. A printing plate in which pixels are manufactured by an etching method or a laser destruction method, wherein the shape of a dot for embedding ink in a light portion is a concave portion, a convex portion, or a smooth portion having ink affinity. The shape as viewed from the front of the dot is X-shaped, or Y-shaped, or at least one type of shape obtained by extending at least one radial short line from a circle,
A printing plate characterized in that the printing plate is formed gradually larger so as to correspond to the gradation.