JP3184707B2 - Mesh gravure printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a yellow , magenta, cyan and black plate from information obtained by color separation of a plate original and performing color printing. More particularly, the present invention relates to a halftone gravure printing plate capable of eliminating moiré caused by overprinting of three or four colors, improving the transferability of ink in a highlight portion, and improving the gradation of light and shade.

[0002]

2. Description of the Related Art FIG. 4 shows a halftone gravure printing plate produced by superimposing a contact screen on an original film, baking it with ultraviolet rays, and developing and etching it. In color printing, a yellow plate, a magenta plate, a cyan plate, and a black plate are respectively created from information obtained by color separation of a plate document and overprinted. In FIG. 4, for example, the left column is yellow.
Over version, the middle column is magenta plate, the right column shows the cyan plate (black version is not shown). In FIG. 4, rhombic cells are shown in white with respect to a copper ground shown in black. Since the three color-separated plates are color-separated even for the same image, cells are formed so that the dot percentages are different at the same position, but in FIG. The rhombic cells up to the shadow portion (an approximately square one rotated by a required angle) are extracted and compared in the same arrangement state. In FIG. 4, by changing the direction of the contact screen,
The crossing angle between the right oblique arrangement direction and the doctor contact line direction of the rhombic cells, 75 degrees in the yellow plate, 55 is a magenta plate
Degrees, 35 degrees for the cyan version, 1 for the black version (not shown)
By setting the angle to 5 degrees, moiré, which may be caused by overprinting of four colors from the highlight portion to the halftone portion, is intended to be eliminated.

FIG. 5 shows a net gravure printing plate produced by an electronic engraving machine which engraves a plate surface with a diamond engraving needle. In FIG. 5, rhombic cells are shown as white outlines with respect to a copper ground shown as a black ground. The diamond-shaped cell produced by the electronic engraving machine is actually slightly horizontal or vertical depending on the size thereof and is considerably distorted, and the central part of the diamond-shaped cell has the deepest pyramid shape. As shown in FIG. 5, b is plate-making by the electronic engraver
Each of the yellow, magenta and cyan versions has a crossing angle of 90 degrees between the obliquely arranged right and left directions of the rhombic cells, and the obliquely rightward arranged direction of the rhombic cells and the doctor contact line direction. Is 45 degrees for the yellow plate, the magenta plate, the cyan plate, and the black plate (not shown).

[0004]

The halftone gravure printing plate prepared by the film exposure-etching method shown in FIG. 4 still has moiré, and further improvement has been demanded. Yellow whose intersection angle with the doctor contact line direction is far from 45 degrees
In the black plate (not shown) and the black plate (not shown), the four sides of the rhombic cell approach the direction of the doctor contact line and the direction perpendicular to the doctor contact line. It was inferior to the version. In the halftone gravure printing plate created by the electronic engraving machine shown in FIG. 5, the intersection angle between the obliquely rightward arrangement direction and the doctor contact line direction is set to 40 for all of the yellow plate, magenta plate, cyan plate, and black plate (not shown). Since it cannot be taken at a temperature other than 5 degrees, there is a drawback that a considerably clear moire is generated from a highlight portion to a halftone portion when color printing is performed. The halftone gravure printing plate created by the electronic engraving machine shown in FIG. 5 has a crossing angle between the obliquely rightward arrangement direction of the rhombic cells and the doctor contact line direction, whichever of the yellow plate, the magenta plate, the cyan plate, and the black plate not shown. Is also 45 degrees, so that the transferability of the ink is better than that of the halftone gravure printing plate shown in FIG. 2, but since the center of the rhombic cell is the deepest pyramid, the transferred ink is Since it becomes heaped and does not become smooth, the dispersibility of the ink is poor, and this is a cause of lowering the gray scale.

According to the present invention, it is possible to avoid the occurrence of moiré due to the high dispersibility of the ink from the highlight portion to the shadow portion when overprinting a three- or four-color-separated plate and performing color printing. It is an object of the present invention to provide a halftone gravure printing plate having good ink transferability and good gradation.

[0006]

According to the present invention, the crossing angle between the oblique right and left arranging directions of the cells from the highlight portion to the shadow portion is ninety degrees, and the doctor contact with the oblique right arranging direction is performed. In a net gravure printing plate in which the angle of intersection with the line direction is smaller or larger than the required angle by 45 degrees,
According to the laser exposure scanning, a cell having a dot percentage smaller than 31% is a rhombic cell having a long shape in a direction orthogonal to the doctor contact line direction and a cell having a dot percentage of 56%. 31%
Cells smaller than 56% have an outer contour of 56%
The cell has the same shape and a hollow diamond-shaped ring, and one diagonal direction of the cell of 31% to 56% is a direction orthogonal to the doctor contact line direction.
And gradually increase according to the gradation.
There is provided a halftone gravure printing plate, characterized in that there was Unishi.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a halftone gravure printing plate of the present invention will be described with reference to FIG. The mesh gravure printing plate of this embodiment is:
Similarly to the halftone gravure printing plates of FIGS. 4 and 5, each of the yellow plate, the magenta plate, the cyan plate, and the black plate (not shown) has the oblique right and left diagonal arrangement directions of the rhombic cells from the highlight portion to the shadow portion. The crossing angle with the arrangement direction is 90 degrees. Then, the halftone gravure printing plate of this embodiment is the same as FIG.
The Like the network gravure printing plate, the crossing angle between the right oblique arrangement direction and the doctor contact line direction of the cell, the yellow version 75
The degree is set to 55 degrees for the magenta plate, 35 degrees for the cyan plate, and 15 degrees for the black plate (not shown) so as to obtain the same moire eliminating effect as the halftone gravure printing plate of FIG.

The screen gravure printing plate of this embodiment is yellow
2 (a) to 2 (h) , the cells of the light portion having a dot percentage of 2% to 27% are arranged in the direction of the doctor contact line in each of the - plate, the magenta plate, the cyan plate and the black plate . vertical direction (Fig. in a direction perpendicular against
A) It is formed in a long, rounded oblong hole shape, and the length and width of the oblong hole gradually increase as the dot percentage increases. About 31% of cells are elongated holes
Less than is the limit.

[0009] Rationale for the numerical calculation of less than about 31%, as shown in (a) in FIG. 3, when the long hole shape dot percent is 30%, the yellow version of the cell, adjacent cells In order to avoid an array in which cells overlap with each other, as shown in FIG. 3B, the number of screen lines is 175 / screen line width per inch.
In microns square, a dot percent of annular rhombic cells groove width of about 15 microns diagonal diameter of the cell is inscribed is 31%, the yellow version of the cell, between the annular rhombic cells and cells Has a screen line width dimension of about 15 microns.

[0010] However, in the case of a long hole-shaped (including an elliptical) cell that is shorter and wider than the long hole-shaped cell whose dot percentage is 30% shown in FIG. Even if the dot percentage is 35%, cells adjacent to each other do not overlap, and the screen line width between cells can be secured to 10 to 15 microns. Further, in the case of a ring-shaped rhombus cell having a larger inner peripheral contour and a dot percentage of 27% than that of a long hole cell having a dot percentage of 31% shown in FIG. 3B, the groove width of the cell becomes smaller. but it may be able to avoid the cell and the cell overlap sequences adjacent, elongated hole-like dot percentage is 31%
Same as cell. Therefore, about 31%, which is the basis for calculating the numerical value of about 31%, is a numerical value that means 31% plus or minus several percent in this specification.

FIGS . 2 (a) to 2 (h) and FIG. 3 (a)
Sea urchin, the direction in which the cell is orthogonal to the doctor contact line direction
When the shape of the long hole is long in the vertical direction in the figure, the overlap of the yellow plate, the magenta plate, the cyan plate, and the black plate is small, and the moire eliminating effect is larger than that of the halftone gravure printing plate of FIG. Can be Further, when the cell is in a long long hole shape in the direction orthogonal to the doctor contact line direction (vertical direction in the drawing), the distance from the Sukurin line doctor contact until Sukurin line is small, the ink doctor When the scraping is performed, the ink enters the cells well, so that the transferability of the ink becomes good and the gradation of light and shade is improved.

Further, the halftone gravure printing plate of this embodiment has a yellow plate, a magenta plate, a cyan plate and a black plate, as shown in FIGS.
Cells with dot percentages less than about 31% to about 56% are formed in diamond-shaped annular cells and are shown in FIG. 2 (m).
As shown, cells having a dot percentage of about 56% are formed in rhombic cells, and furthermore, as shown in FIGS. 2 (i) to 2 (m).
As shown, cells having a dot percentage of about 31% to about 56% have two diagonal directions corresponding to the doctor contact line direction (see the figure).
Right and left directions) and a direction perpendicular to this (in the figure,
(Up-down direction) is formed in a diamond-shaped annular cell or a diamond-shaped cell, and as shown in FIGS.
Dot percent is less than about 31% to about 56%
A cell whose outer peripheral contour is about 56% shown in FIG.
As the groove width increases inward, the dot percentage gradually increases.

For cells having a dot percentage of about 31% to about 56% shown in FIGS. 2 (i) to 2 (m) , the two diagonal directions are aligned with the doctor contact line direction and the direction perpendicular thereto. , In such a hollow annular rhombic cell
If present, make sure that it is not parallel to the doctor contact line
And the groove direction is 45 ° to the doctor contact line direction
Especially due having a slope, when performing scraping ink by a doctor, the ink becomes from entering favorably to the cell, shading gradients improvement enables good transfer of the ink from the cell to the paper To do that.

The cells having a dot percentage smaller than about 31% to about 56% shown in FIGS. 2 (i) to 2 (l) are formed in the diamond-shaped annular cells, and the dot percentage shown in FIG. % Is formed in a rhombic cell, as shown in FIG. 3 (c), as shown in FIG. 3 (c), where the number of screen lines is 175 lines / inch. The dot percentage of the ring-shaped cell with a rounded corner is about 56%, as shown in FIG.
In the yellow version of the cell , the dot percentage shown in FIGS. 2 (i) to (l) is reduced from about 31% based on the screen line width dimension between the ring-shaped diamond cells being about 15 microns . This is because, for cells smaller than about 56%, the dot percentage is gradually increased by gradually increasing the groove width inward with the same outer contour and the same groove shape. In other words, the diamond-shaped annular cell in which the hollow part (island-shaped non-cell part) is gradually reduced is
The outer contour is adjusted to the size of the diamond cell, which is about 56%, based on the fact that the diamond-shaped cell is about 56% when the hollow portion is eliminated.

The percentage of dots of a ring-shaped rhombic cell having a diagonal diameter inscribed in a square having a screen line width of 145 microns / screen line number per 175 lines / inch is about 56%. Sometimes, the screen line width between adjacent cells becomes 15 microns (see FIG. 3B). Increasing the corner roundness reduces the dot percentage by about 2%, while the screen line width between cells can be as small as 8 microns.
The screen line width between cells adjacent to each other is
The dot percentage of the ring-shaped rhombus cell when sized beyond the 45 micron square is 3 to 3% higher than 56%.
5% larger. Therefore, the basis of the above-mentioned numerical calculation of about 56% is a numerical value that means 56% plus or minus several percent in the present specification.

2 (i) to 2 (l), the cells in the middle portion where the dot percentage is smaller than about 31% to about 56% are not formed as rhombic cells but have the same outer peripheral contour. The shape of the annular rhombus in which the groove width gradually widens inward in the shape is compared with the case where the dot percentage is the same as the rhombic cell (compared to the corresponding rhombic cell of the dot percentage in FIGS. 4 and 5). This is because the degree of overlapping of the inks is reduced, and a large moiré eliminating effect is obtained, and the degree of dispersion of the ink is large.

The cells in the shadow area where the dot percentage exceeds about 56% shown in FIGS. 1 and 2 (n) to 2 (p) are rhombic cells, and one side of the cells is aligned with the diagonally right arranging direction of the cells. I do. That is, as can be seen from FIG. 1, the obliquely arranged right angle of the cell with respect to the doctor contact line is yellow.
Is 75 ° In the chromatography plate, 55 ° In the magenta plate,
35 ° for the cyan version, 15 ° for the black version
°, and the inclination angle of the cell also coincides with the oblique right array angle of the cell. Therefore, the cells in the shadow area where the dot percentage exceeds about 56% are the same as the halftone gravure printing plate shown in FIG. This is done for the following reason. In other words, in order to eliminate moiré, it is preferable that one diagonal direction is formed to be a direction orthogonal to the doctor contact line direction even for cells in a range exceeding about 56%. Then,
When etched, the screen lines will be lost. To avoid missing the screen,
For cells in a range exceeding about 56%, one diagonal direction of the cells is not set to the direction orthogonal to the doctor contact line direction, and the four sides of the cells are set to the right diagonal arrangement direction of the cells as in the case of FIG. It is made to coincide with the diagonally left array direction.

[0018] The net gravure printing version of this embodiment, yellow
-In all of the plates, the magenta plate, the cyan plate, and the black plate, the shape of the cell in the most shadow part is such that the screen lines that are bent at almost right angles are in a squamous arrangement, and three cells are at the intersection of the screen lines. It communicates with a width less than the width.

As a specific example of the method of manufacturing the mesh gravure printing plate, a plate surface plated with ballad copper to about 100 microns is polished with a grindstone or a buff, surface activated, and then an argon / neon gas laser beam. A photosensitive resin film having high sensitivity characteristics that can be cured by a weak laser beam such as mu is applied and formed so as to have a thickness of 5 to 8 microns, and a coating for preventing oxidation of the photosensitive resin film is further overcoated, Next, 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 so that adjacent irradiated lines on the plate surface of the laser beam are overlapped and deviated, and the printing information is obtained. By performing flashing irradiation of the corresponding laser beam, after writing negative print information on the photosensitive resin film, development is performed and After dissolving the unexposed portion of the conductive resin film, the resist is heated and cured, and then etched to engrave positive printing information on the plate surface in a halftone dot shape, stripped the resist, and plated with chrome to give the printing durability .

The halftone gravure printing plate of the present invention includes not only a roll printing plate but also a lithographic plate. Further, the present invention is not limited to the plate making method shown in the above-described embodiment, that is, the method of forming a resist image by laser exposure and development and then etching, but the roll surface may be made of epoxy resin or the like containing magnetic powder. YAG (Ya)
G) A net gravure printing plate in which cells are directly engraved with a high-intensity laser such as a laser may be used. Further, according to the present invention, the crossing angle between the obliquely rightward arrangement direction of cells from the light portion to the shadow portion (the direction of the upwardly inclined line in the figure) and the doctor contact line direction (the direction of the horizontal line in the figure) , for example, 75 Degrees, cyan version 55 degrees, black version 3
5 degrees may be 15 degrees for the yellow plate, or 65 degrees for the magenta plate, 45 degrees for the cyan plate, 25 degrees for the black plate, and 5 degrees for the yellow plate. In the description of the above embodiment, the intersection angle between the right oblique arrangement direction and the left oblique arrangement direction of the cell from the light portion to the shadow portion is 90 degrees, and the intersection angle between the right oblique arrangement direction and the doctor contact line direction. Mentioned a net gravure printing plate with a required angle smaller or larger than 45 degrees. The crossing angle between the obliquely rightward and leftwardly arranging directions of the cells from the light portion to the shadow portion is 90 degrees .
Direction) and the doctor contact line direction (horizontal line direction in the figure) have an intersection angle of 45 degrees ,
Cells in the range where the dot percentage exceeds about 56% are the same as those in FIG.

[0021]

As described above, according to the halftone gravure printing plate of the present invention, when the color separation is performed by overprinting a three- or four-color separation plate, the color from the highlight part to the halftone part is obtained. As a result, moire does not occur and the density looks large even with the same amount of ink, and if the ink is scraped off with a doctor, the ink As a result, the transferability of the ink becomes good and the gradation of light and shade is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a halftone gravure printing plate of the present invention.

FIG. 2 is a design diagram of a cell showing a halftone gravure printing plate of the present invention.

FIG. 3 is a diagram illustrating an arrangement of cells showing a halftone gravure printing plate of the present invention.

FIG. 4 is a diagram showing a conventional mesh gravure printing plate created by superposing a contact screen on an original film, baking the film with ultraviolet rays, and developing and etching.

FIG. 5 is a diagram showing a net gravure printing plate created by an electronic engraving machine for engraving a plate surface with a diamond engraving needle.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shinya Nabezaka 2494-10 Kitamachi, Takamatsu City, Kagawa Prefecture Inside NaveProcess Co., Ltd.

Claims (1)

(57) [Claims] 1. The crossing angle between the obliquely rightward and leftward arranging directions of cells from the highlight portion to the shadow portion is 90 degrees, and the crossing angle between the rightward arranging direction and the direction of the doctor contact line is four. In a net gravure printing plate having a required angle smaller or larger than 15 degrees, a cell having a dot percentage smaller than 31% by laser exposure scanning has a long shape in a direction orthogonal to the doctor contact line direction. , A rhombic cell that is a cell with a dot percentage of 56% ,
The cell whose dot percentage is smaller than 31% to 56% is the same shape as the cell whose outer peripheral contour is 56% and has a hollow diamond shape, and one diagonal line of the cell whose outer contour is 31% to 56%. direction, as well as to be a direction orthogonal to the doctor contact line direction, the gray gradient
A halftone gravure printing plate characterized in that it gradually increases in size .