JPH0848017A - Plate making method - Google Patents

Abstract

PURPOSE:To obtain a plate making method suitable for high-grade printing of a medium number of sheets and utilizable by an individual or in an office. CONSTITUTION:In a plate making method, a plate material 6a composed of a synthetic resin sheet is wound around a cylindrical member 17 to be rotated and irradiated with laser beam from a laser irradiation means 24 to form recessed parts 15 changed in depth and/or area corresponding to the variable density of input image data to simply obtain a plate cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intaglio plate making method suitable for use in gravure printing, and more particularly to a plate making method in which a concave portion corresponding to the shade of input image data is formed using a laser.

[0002]

2. Description of the Related Art Conventionally, many printing methods have been proposed for printing, and relief printing, planographic printing, intaglio printing, stencil printing, etc. have been used for plate making. Particularly, intaglio printing is used for high-speed printing of photographic images and the like on paper with a large number of copies. The most practical gravure plate making process among the intaglio plates will be described with reference to FIG.

The plate surface of the cylinder plate for gravure printing is printed so that the lightness and darkness of the original (photograph) causes a difference in the thickness of the corrosion-resistant film on the plate surface, and the metal surface of the plate surface is etched from above.
Printing is performed by forming a set of recessed dots having different depths and filling the recesses with ink.

As shown in FIG. 5A, the gravure plate manufacturing process is performed by attaching a gelatin film to a special thick paper 1 and sensitizing it with dichromate to form a photosensitive film 2.
issue) Place a mesh screen 4 on 3 and irradiate light to print the mesh. When the photosensitive film 2 is printed in a mesh shape in this way, the final plate surface has a square so-called solid black pattern. Is formed.

Next, as shown in FIG. 5B, a negative image is made on the basis of a photograph or a picture, a transparent positive image is made on the basis of this negative image, and the transparent positive image 5 is placed on the mesh-baked carbon tissue 3. Then, irradiate with light and bake.

Next, the surface of the cylindrical plate cylinder 6 as shown in FIG. 6 and FIG. 7 is thickly copper-plated, and the surface of the copper film 7 is wetted with alcohol to bring the photosensitive film 2 of the carbon fish 3 into close contact. And wrap it around.

Next, as shown in FIG. 5C, the carbon fish 3 was immersed in hot water at about 40 ° C. and the paper 1 was peeled off. The unexposed gelatin and the exposed mesh and the screen were adjusted according to the degree of light exposure. Leave the gelatin.

Next, when asphalt is applied to a portion other than the screen to prevent etching and etching with the ferric chloride solution 9, pits having different depths are formed according to the degree of exposure, as shown in FIG. 5D. A part of the plate cylinder 6 thus completed is put in an ink reservoir 10 containing a solvent type ink as shown in FIG. 7, and excess ink is scraped off by a doctor 11. Since the doctor 11 is crimped to the plate surface of the plate cylinder 6 with a knife having a sharp edge, a large number of depressions (hereinafter referred to as cells) formed on the plate surface.
Scrap ink other than the ink that has clogged up.

The impression cylinder 12 presses the paper 13 to be printed on the plate surface of the plate cylinder 6 to adsorb the ink 14 on the paper 13 as shown in FIG. The concentration of this adsorption ink varies depending on the depth of the cell etched on the plate surface of the plate cylinder. That is, since a large amount of ink is filled in the deep cells, a small amount of ink is filled in the shallow cells, and the thin cells become thin.

[0010]

According to the plate cylinder for gravure shown in the above-mentioned conventional structure, the plate cylinder is good for printing a large amount of printed matter in order to make it for each printing, but the number of printed sheets is large. If the number of sheets is several tens to several thousand, the printing cost per sheet will increase significantly.

Further, not only the plate making process is complicated, but also the number of processes is increased due to the process of making a transparent positive image and the like. Further, a metal cylinder for performing copper plating and etching is required on the plate cylinder 6. For this reason, there has been a problem that the plate making process is so large that no plate can be directly made in the office or by an individual, which is expensive.

The present invention has been made in view of the above problems, and it is an object of the present invention to obtain a low-priced plate cylinder that can be used by individuals or offices who are suitable for high-quality and medium-volume printing. A plate making method is provided.

[0013]

The plate making method of the present invention is shown in FIG.
As shown in one example in FIG. 2, a plate material 6a made of a thermoplastic synthetic resin containing black paint is wound around a rotatable cylindrical member 17, and the plate member 6a is rotated while rotating the cylindrical member 17. In the plate making method, the synthetic resin is scattered or sublimated by irradiating the surface of the plate with a laser beam to form the concave portion 15 on the surface of the plate material 6a.

In the plate-making method of the present invention, since the laser beam is used to form the cells, which are formed by the semiconductor laser, on the plate surface of the thermoplastic resin sheet, the recesses having a depth and an area corresponding to the light and shade of an image, are changed. You can easily get an intaglio plate cylinder (gravure plate).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view of a plate cylinder used in the plate making method of the present invention, and FIG. 2 is a side sectional view of the plate cylinder in an assembled state.

In FIGS. 1 and 2, the cylinder 17 is a metallic cylinder. A synthetic resin plate sheet 6a as a plate material is wound along the outer diameter of the cylinder 17, and the cylinder 17 is covered with a flat head screw 6b or the like. It is fixed to the mother screw 17a that was drilled. This fixing method can be selected as appropriate, and can be fixed with, for example, a double-sided tape.

The material of the plate sheet 6a is preferably a thermoplastic resin which has a relatively narrow melting point distribution range, has a hardness during curing, and has a resin that scatters or sublimes at a low temperature during melting, such as polyethylene resin, acrylic resin, and the like. A polypropylene resin containing about 20% carbon can be used.

The thickness t of the plate sheet 6a is selected to be about 200 microns. Metal caps 19L and 19R are inserted at the left and right ends of the cylinder 17 so as to fix the left and right ends of the plate sheet 6a to form the plate cylinder 6. Shafts 18L and 18R are erected on the caps 19L and 19R, and are connected to a plate cylinder rotating motor 36 (not shown), and the plate cylinder 6 is rotated clockwise, for example, in the direction of arrow B as shown in FIG. .

As shown in FIG. 2, the plate cylinder 6 is irradiated with a laser beam through a focusing lens 23 to focus on the surface of the synthetic resin plate sheet 6a to melt the surface of the plate sheet and scatter the synthetic resin. Be sublimated.

In this case, by modulating the laser or changing the laser irradiation time for the recess 15 which is one recess, the amount and size of the recess that scatters or sublimes the plate surface material is adjusted, and the volume corresponding to the gradation is adjusted. The recess 15 is formed. That is,
As shown in FIG. 2, the recess 15 as a recess is configured so that the amount of the plate material scattered by the laser beam changes the depth d or the area s depending on the density of the image input signal.

FIG. 3 is a conceptual diagram for forming the concave portion 15 in the plate sheet 6a by using the small energy emission type semiconductor laser 20 of about 1 W.

In FIG. 3, a video input signal 21 captured by an image scanner or the like is supplied to the semiconductor laser 20,
The drive current is turned on / off by the PCM image input signal and directly modulated. Therefore, the laser beam emitted from the semiconductor laser 20 blinks in synchronization with the video signal. The laser beam emitted from the semiconductor laser 20 is collimated optical system 22.
Is formed into parallel light with the plate sheet 6 through the focusing lens 23.
Irradiation is focused on the surface position.

Semiconductor laser 20, collimate optical system 2
2. The laser block 24 including the focusing lens 23 is initially focused on a predetermined position on the leftmost end side of the plate cylinder 6. The plate cylinder 6 is a motor 36 for rotating the plate cylinder shown in FIG.
Since the drum plate 6 is rotated once, the concave portion 15 for one track along the circumference is scattered by the laser beam to form a concave portion 15 for a predetermined one track.

Next, the laser block 24 is moved by one pixel in the axial direction of the plate cylinder by the laser block moving motor 34 shown in FIG. 4 to scatter the surface of the plate sheet 6a. Is formed. When such an operation is sequentially performed over the entire surface of the plate cylinder 6, the synthetic resin material on the surface of the plate sheet 6a forms the concave portion 15 in which the depth d or the area s is changed corresponding to the shade of the image input signal 21. It can be formed over the entire surface.

FIG. 4 shows a system diagram for supplying the semiconductor laser 20 with data corresponding to the light and shade of a video signal.

In FIG. 4, the input operation unit 30 supplies a status signal 31 such as stop and reset to a microcomputer (hereinafter referred to as CPU) 32.

The CPU 32 supplies a forward rotation pulse or a reverse rotation pulse to the laser block moving motor driver 33 and the plate cylinder rotating motor driver 35, and the laser block moving motor 3 is supplied.
4 and the plate cylinder rotating motor 36 are rotationally driven.

The plate cylinder 6 is rotated by the motor 36 for driving the plate cylinder, and the concave portion 15 corresponding to the data of the image input signal 21 is formed on the surface of the plate sheet 6a by the semiconductor laser 20.
After the rotation, the CPU 32 controls so that the laser block moving motor 34 is moved by one pixel data to form the concave portion 15 along the circumference of the plate cylinder 6 according to the shading of the screen.

The data ROM 38 stores, for example, a video signal
Digital image data D obtained by capturing one frame with an image scanner or the like is stored. Address A is CP
Data ROM from address counter 37 via U32
38. Image data D according to this address
Is supplied to the grayscale ROM 41, and the image data D
The grayscale data D ₀ according to the lightness and darkness of is output according to the grayscale ROM 41.

Address A _{0 of the} grayscale ROM 41
Supplies the pulse generated by the pulse generator 39 to the counter 40.
The modulated pulse is supplied to the AND gate circuit 42 from.

Gray scale data is supplied from the gray scale ROM 41 to the AND gate circuit 42, and the semiconductor laser 20 is driven via the laser driver 43.

In this example, a black paint such as carbon is mixed into a thermoplastic resin material that melts at a low temperature to improve heat absorption, and the depth of the plate sheet surface or / and / or directly with a small energy of about 1 W as in a semiconductor laser. Since it scattered while controlling the area, it is possible to obtain a gravure plate that can be directly plate-made by an office or an individual without the complicated process of plate-making as in the past, and by using a laser beam with an electric signal. Since the plate can be made directly, various image inputs can be supplied.

The present invention is not limited to the above embodiments, but can be variously modified without departing from the gist of the present invention.

[0034]

According to the plate-making method of the present invention, the plate-like sheet of the thermoplastic resin is melted by using the semiconductor laser so as to control the depth and / or the area of the recess, so that the plate-making process is simple and the office It is possible for an individual to directly make a plate, and an inexpensive intaglio plate cylinder can be directly obtained by an electric signal.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a plate cylinder used in a plate making method of the present invention.

FIG. 2 is a side sectional view of the assembled state of FIG.

FIG. 3 is a conceptual diagram showing a laser optical system of the plate making method of the present invention.

FIG. 4 is a system diagram of a laser scanning system of the present invention.

FIG. 5 is a manufacturing process diagram of a conventional gravure plate.

FIG. 6 is an enlarged view of a main part of a gravure printing plate cylinder.

FIG. 7 is a conceptual diagram showing gravure printing.

[Explanation of symbols]

 6 Plate cylinder 15 Recessed portion 17 Cylinder 18L, 18R Shaft 19L, 19R Cap 20 Semiconductor laser

Claims (1)

[Claims] 1. A plate material made of a thermoplastic synthetic resin containing black paint is wound around a rotatable cylindrical member, and the surface of the plate member is irradiated with a laser beam while rotating the cylindrical member. A plate-making method in which the synthetic resin is scattered or sublimated to form recesses on the surface of the plate material.