JPH1044635A - Gravure fine line printing plate and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure printed matter not having a jaggedness but having a sharp feeling in the contour of a fine line image and high in resolving power and a gravure printing plate therefor. SOLUTION: In a gravure printing plate, by providing banks 3 traversing fine line grooves 5 at a constant pitch, cells 2 formed surrounded by both side walls of the grooves 5 and the side walls of the adjacent bank 3 are arranged in the groove direction through the banks 3. The crossing angle of the grooves 5 and the banks 3 may be set to a smaller angle range of 45-90 deg.. Further, a notch 4 may be provided on the single side or both sides of the bank 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate and a printed matter which faithfully reproduce a fine line image by a gravure printing method.

[0002]

2. Description of the Related Art In order to reproduce an image having a fine line pattern, for example, a grain pattern having fine conduit grooves, on a printed material by a gravure printing method, the following method is generally employed. Based on the original film or image data having a fine line pattern, this is screened, quantized into cells (halftone dots), scanned by a gravure engraving machine to create an engraved line art plate, and gravure printed. An edge of the original film having a fine line pattern, that is, a protruding portion of the cell along the outline of the fine line pattern is cut, and a border (frame) surrounding the periphery of the fine line pattern is formed.
Is formed, the original film is exposed to a resist film, and a line drawing plate is formed by a direct or conventional corrosion method, and gravure printing is performed. (Actual fairness 2-
No. 13154) Image data of a fine line pattern is output as a halftone dot on a film using a high-resolution image setter, and a fine line image plate is formed by a direct or conventional corrosion method, and gravure printing is performed. The fine line image is not divided into cells, but is formed as a concave portion communicating the entire pattern, and is filled with ink and printed. (Japanese Patent Laid-Open No. 5
No. 0-152804)

[0003]

Generally, in a gravure print, an image is quantized into cells, so that the thinner the image, the more jaggedness around the image becomes more noticeable.
There is a problem that only reproduced images with poor sharpness and realism can be obtained. This is a phenomenon that can also be seen in thin lines such as characters. This is because cells that normally should keep a square shape become irregular shapes such as triangles and pentagons around the image area as shown in FIG.
Also, because the cell depth becomes extremely shallow, ink transfer is not sufficiently performed in this portion. In the case of the gravure printing method described above, there is a problem that when the outline of the image portion is jagged and the line width of the thin line is extremely small, the line is not connected as a line and a dotted line is formed. In the case of the gravure printing method described above, although somewhat improved, the same is also true in that missing cells are arranged at the periphery of the fine line image, and in this part, the edge is sharp, There is a problem that a sharp printed image cannot be obtained due to jaggedness due to poor transfer of ink in a portion. In the case of the above printing method, cells are not formed in the image area, so the sharpness around the fine line image is improved, but when the ink is scraped off by the doctor blade during printing, a uniform and sufficient ink is printed on the printing plate. And the printed matter having high density cannot be obtained. The present invention has been made in view of such a problem, and an object of the present invention is to provide a gravure printing plate in which the outline of a fine line image is sharp and the ink density is stable over the entire image portion, and a printed material using the gravure printing plate.

[0004]

According to the present invention, there is provided a gravure fine line printing plate according to the present invention, wherein a bank is provided at a constant pitch with respect to a fine line-shaped groove. The cells formed by being surrounded by the side walls of the bank adjacent to both side walls are to be arranged in the groove direction, and the adjacent cells are separated by notches provided on one side or both ends of the bank. It may be communicated. Further, the printed matter according to the present invention is a printed matter in which an ink layer is formed in a thin line shape on a substrate to be printed, and the thin line is formed from an aggregate of cells separated by a linear blank portion crossing the thin line. It may be formed as a gist, and adjacent cells may be connected to each other on one or both sides of the bank by an envelope of each cell.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings. FIG. 1 is an explanatory diagram of the state of reproduction of a fine line image in the current gravure printing of the corrosion method. FIG. 1A shows a print image 10 having a pattern composed of fine lines. FIGS. 1B and 1C are enlarged views of an image portion (a portion filled with ink) corresponding to a fine thin line portion and a thick thin line portion in the gravure printing plate. Unlike the printing plate 1 which is a non-image part, the image part has cells 2, 2 'which are concave parts defined by orthogonal banks 3 arranged. The cell 2 in the center of the fine line drawing portion has a regular square shape, but its shape is not constant around the drawing portion, and the deformed cell 2 ′ in which the corners such as a triangle, a pentagon, etc. have become acute angles, The depth is also shallow. In the conventional print image 10 obtained by gravure printing using such a gravure printing plate, the peripheral portion of the image is markedly jagged, has a very poor sharpness, and the density around the image portion is reduced. This is because the planar shape of the cell 2 'shown in FIGS. 1 (b) and 1 (c) is not faithfully reproduced in the printed matter, and the amount of transferred ink is not constant but reduced in the deformed cell 2'. This is because they do not transfer at all and are missing.
This jaggedness effect is not so noticeable when the thin line has a thickness, but becomes more noticeable as the line becomes thinner. Also,
Although illustration is omitted, in FIGS. 1 (b) and 1 (c), if the running direction of the bank is divided so as to be parallel or perpendicular to the thin line, the corner of the cell 2 'can be prevented from becoming an acute angle. This time, the width of the cell 2 'becomes extremely thin, and the ink transferability at that portion is extremely reduced. Therefore, the transition of the peripheral portion of the thin wire becomes unstable. Therefore, a gravure printing plate which can easily obtain a sharp gravure fine line printed matter without the jaggedness effect will be described below.

FIG. 2 is an explanatory view of a cell of a gravure fine line printing plate according to the present invention. In the gravure printing plate according to the present invention, as shown in FIG. 2A, the banks 3 crossing the grooves 5 are arranged at a constant pitch in the direction substantially perpendicular to the longitudinal direction of the grooves 5 with respect to the fine grooves 5. And a recess formed by the side wall of the bank 3 and the side wall of the bank 3 adjacent to the side wall of the groove 5.
The cells 2 having substantially the same shape with little deformation are connected via a bank 3. In addition, as shown in FIG.
At the smaller angle 4
It may be changed in the range of 5 ° to 90 °. However, it is not preferable that this angle is less than 45 ° because the corner angle of the cell 2 becomes too sharp and the transferability of the ink becomes poor. As shown in FIGS. 2C and 2D, notches 4 may be provided on one or both sides of the end of the bank 3. By cutting off the ends in such a manner that the cells communicate with each other, a part of the ink in the cell 2 moves between the adjacent cells, and the filling of the ink after scraping by the doctor blade in each cell is uniformized. In addition, the transferability of the ink to the substrate is improved. The width of the notch 4 must be limited to about 15% of the entire length of the bank 2 at each end. This is because if the numerical value exceeds this value, the partition effect of the cell 2 by the bank 3 is reduced, and the filling amount of the ink in the cell is reduced. The outer edge of the notch 4 is continuously connected to the outer periphery of each cell. That is, the notch 4 is designed to be the envelope of the aggregate of the cells 2. The shape of the bank 3 crossing the groove 5 may be a curve (a circular arc or the like) other than a straight line.

FIG. 3 is an explanatory view of a gravure fine line printing plate according to the present invention and a fine line image to which a printed matter is effectively applied. The fine line image to which the gravure fine line printing plate and printed matter according to the present invention are applied may include a conduit groove of wood grain, various fiber bundle patterns, a hairline pattern, characters, symbols, geometric patterns, and the like. The effect of the gravure fine line printing plate and the printed matter according to the present invention is that the fine line width is 10 to 100 μm, the bank width is 5 to 100 μm, preferably 35 to 40 μm, and the pitch of the bank 3 is as shown in FIG. 15-6
For fine lines 5 in the range of 00 μm, preferably 200-300 μm. In particular, when the ratio between the fine line width and the pitch of the bank 3 (cell pitch) is line width / pitch <3,
That is, when the fine line width becomes a size that cannot be ignored compared to the cell pitch, the gravure fine line printing plate and printed matter according to the present invention exhibit excellent effects.

Next, a method for producing a gravure fine line printing plate according to the present invention will be described by taking, as an example, a wood grain pattern plate making in which fine lines occupy an important element of the design. FIG. 4 is a manufacturing flowchart of the gravure fine line printing plate according to the present invention. As shown in FIG. 4, the production of a gravure fine line printing plate according to the present invention starts with photographing using a natural wood as an original. This photographing is divided into photographing 4-1 of the grain pattern other than the thin line portion and photographing 4-3 for extracting only the thin line such as the conduit groove and the fiber portion. The image information obtained by the former is recorded on a wood-grain pattern original film after being divided into ordinary square cells by a generally-known wood-grain pattern making plate 4-2. A typical film master is a film which has been exposed and recorded as a negative or positive image by silver halide photography. On the other hand, the fine line image information of only the conduit groove and the fiber portion obtained by the latter is recorded on the original film of the fine line image divided into cells as described above through steps 4-4 to 4-9. Endless retouching of both original films 4-
In step 10, a gravure fine line printing plate is manufactured by the following printing plate 4-11 using both of the retouched films.

As the method of the wood grain pattern plate making 4-2 and the printing plate 4-11, any of the following known methods may be employed. After correcting (retouching) a positive film image obtained by synthesizing the original film obtained by plate making of the wood pattern and the original film obtained by making only the fine line image, and performing an endless process (in the case of a rotary printing plate), Carbon tissue (photosensitive resist of dichromated gelatin applied to paper)
A positive film image is exposed on the plate, the carbon tissue is transferred to the plate material surface, a resist film is formed by development, and a cell is formed on the plate surface by being corroded from above with a corrosive solution such as ferric chloride. And then remove the resist. The same correction and processing as in (Conventional gravure plate making method) are performed, a photosensitive resist film is formed on the film original directly on the plate material surface, and the original film is exposed to the photosensitive resist film and corroded in the same manner as after development. Method. (Direct etching method) A film image or document itself is input to a scanner, converted into a digital signal, and digitized image data is numerically converted to endless by a computer.
After processing such as correction (retouching) and gradation correction, the thin line image is divided into cells by the bank perpendicular to the thin line as described above, and the image other than the thin line image is converted into a normal square cell. Segment and then process this processed data
A method of converting and engraving cells on a plate material with an engraving machine.
The same processed digital data as in (engraving gravure plate making method) is DA converted, the laser beam is modulated (beam diameter etc.), the resist film formed on the plate material is exposed in advance, and then A method of forming cells by performing corrosion. The material of the gravure fine line printing plate (printing plate) according to the present invention is copper,
Any of metals such as iron, ceramics, and resins may be used, and chromium, ceramics, or the like may be plated thereon to increase the printing durability. The shape of the printing plate is
Either a lithographic plate or a cylindrical plate (cylinder) may be used.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The points of the method for producing a gravure fine line printing plate and printed matter according to the present invention will be described more specifically with reference to FIG. In order to obtain fine line image information of conduits, fiber parts, etc., first,
A black ink is filled in a concave portion existing in a conduit or a fiber portion of a raw wood to be a manuscript, and the black film is filled with a black ink. The negative film is obtained by photographing with a camera 4-3. An underlay film recorded by binarization was prepared. The endless retouching 4-4 was performed according to the circumference of a plate cylinder used for printing the underlay film to obtain an endless fine line image original film. At this time, we tried to synchronize the pattern with one grain pattern. The above original film is divided into pieces that can be input to the flatbed scanner by adding picture doubles, 4-5,
The data was input to a layout scanner 4-6, and the optical density of the original film image was converted into digital data by image-to-digital conversion. The above data was thinned on a computer and the line width was set to 2
It was adjusted to a range of 0 to 100 μm. Are drawn at a pitch in the range of 200 to 300 μm perpendicular to the longitudinal direction of the fine line. The width of the line is set to a width of 35 to 40 μm such that a depth of 10 to 15 μm remains after the completion of corrosion, assuming a plate depth of 30 μm. These lines were fitted into the fine line image, and image data corresponding to FIG. 2A was created as digital data. Was exposed to a photosensitive film from an imagesetter and output as an optical image. The output resolution in that case was 100 lines / mm. The overlay is exposed to the photosensitive film while being aligned with the woodgrain original film excluding the conduit grooves by the woodgrain pattern making machine 4-2, which has been separately advanced, and the endless processing and retouching work 4-10 are performed on the film. Was. Unlike the recessed portion, the woodgrain pattern excluding the conduit groove was formed by filling the ink with the same color as the woodgrain wood surface and then photographing. The film obtained in the above was used as the final master, and was exposed in close contact with a copper cylinder (the inside was an iron core) on which a photosensitive resist film had been formed in advance. After development, it was corroded with an aqueous ferric chloride solution, and then remained. The resist film was removed, and a printing plate step 4-11 by a direct printing method was performed to prepare a gravure fine line printing plate according to the present invention. Using the gravure fine line printing plate having cells as shown in FIG. 2A manufactured by the above method, gravure printing was performed using dark sepia ink, and an example sample was prepared. In comparison with a comparative example printed using a fine line printing plate having a normal cell shown in FIG. 1 and made using a conventional gravure screen, in the example sample, the jaggedness of the fine line image disappeared, It was clear that it was excellent in realism. Further, in the examples, it was visually confirmed that even thin lines which could not be reproduced in the comparative example were reproduced. The sharpness of the printed matter of the example was comparable to that of offset printing using a screen of 300 lines / inch.

[0011]

According to the present invention, in the fine line drawing portion of the printing plate, a cell is formed by providing a bank crossing the groove at a constant pitch, so that the contour of the fine line drawing portion due to the projection of the cell shape is obtained. By eliminating jaggedness and stabilizing the cell shape, there is no portion where ink transfer is insufficient, and a printed image having a sharp feeling and a realistic feeling can be obtained.
In addition, thin lines that could not be reproduced by conventional gravure prints can be reproduced, and the limit value of the fine line width can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a reproduction state of a thin line image in the current gravure printing of a corrosion method.

FIG. 2 is an explanatory view of a cell of a gravure fine line printing plate according to the present invention.

FIG. 3 is an explanatory diagram of a gravure fine line printing plate according to the present invention and a fine line image to which a printed matter is effectively applied.

FIG. 4 is a manufacturing flowchart of a gravure fine line printing plate according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate surface 2 cell 2 'deformation cell 3 Bank 4 Notch 5 Groove 10 Conventional printing image

Claims (4)

[Claims] 1. A bank formed at a constant pitch in a thin line-shaped groove crossing the groove, so that a cell formed by a side wall of the bank adjacent to both side walls of the groove is formed in a groove direction. A gravure fine line printing plate characterized by being arranged in a line. 2. The gravure printing plate according to claim 1, wherein adjacent cells communicate with each other by notches provided at one or both ends of the bank. 3. A printed material in which an ink layer is formed in a thin line shape on a substrate to be printed, wherein the thin line is formed from an aggregate of cells separated by a linear blank portion crossing the thin line. Printed matter characterized by being done. 4. A printed material in which an ink layer is formed in a thin line shape on a substrate to be printed, wherein the thin line is composed of an aggregate of cells separated by a linear blank portion crossing the thin line. Printed matter, wherein adjacent cells are connected to each other on one or both sides of the bank by an envelope of each cell.