JPS61179740A - Laser plate making apparatus - Google Patents

Abstract

PURPOSE:To enable the inside-out plate making without using large capacity memory, by constituting the title apparatus so that at least one of the main scanning direction and a sub-scanning direction of a plate making part can be selected in a direction reverse to that of a reading part. CONSTITUTION:A reading part 1 is constituted of a main scanning mechanism comprising a reading drum 11 rotating while winding up an original, a reading optical mechanism consisting of a reading laser beam source 12, reflective mirrors 13a, 13b, 14, a condensing lens 15 and a photoelectric converter 16 and a sub-scanning mechanism equipped which an electromotor 17 for moving the reflective mirror 14 to the axial direction of the reading drum 11. A plate making part 2 is similarly constituted of a main scanning mechanism, a plate making optical mechanism and a sub-scanning mechanism. At least one of the plate making main scanning direction and sub-scanning direction is selected in a direction reverse to respective reading main scanning direction and sub- scanning direction to obtain a plate of an image reverse to the original.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laser plate making apparatus that uses a laser beam to create a printing plate.

BACKGROUND OF THE INVENTION Recently, laser plate making apparatuses have been developed that utilize laser beams to create plates for printing.

Such a laser engraving apparatus includes an original image reading section and a engraving section that forms a concavo-convex pattern on a plate-making material corresponding to the read original image. The original image reading section creates an electrical signal with an amplitude corresponding to the brightness of the original image by two-dimensionally scanning a flat original image with a light beam and photoelectrically converting the reflected or transmitted light beam. On the other hand, the plate-making section scans the plate-making material two-dimensionally with a laser beam whose intensity corresponds to the amplitude of the electric signal read, causing local destruction or deformation of the plate-making material, thereby forming the original image. A pattern of unevenness corresponding to brightness and darkness is formed on the plate-making material.

In the above-mentioned laser plate-making apparatus, it is necessary to form a concave-convex pattern on the plate-making material by turning the original image upside down, similar to the printing type of a typewriter. given that.

It is necessary to form a plate-making plate on a plate-making material as shown in FIG. In addition.

In Figure 3, the diagonal line with an arrow is a scanning line,
and Y are the main scanning and sub-scanning directions during reading and plate making.

Conventionally, in order to create the above-mentioned upside-down plate making (figures that are line symmetrical in the sub-scanning direction as shown in FIG. 3).

A configuration is adopted in which the read original image is A/D converted and stored in the -H memory, an inverted pattern is created through program editing processing, and this is supplied to the plate making section.

In addition, even for complex figures that are difficult to draw, a configuration is adopted in which a desired target figure is created using a large-capacity memory and program editing processing, and this is supplied to the plate-making section.

Problems to be Solved by the Invention The above-mentioned conventional laser engraving apparatus requires a large capacity memory in order to create a desired target figure such as a reversed pattern, which raises the problem of an increase in the cost of the entire apparatus. .

Structure of the Invention The laser plate making apparatus of the present invention solves the problems of the prior art as described above. By making it possible to select the desired image, a memory for inverting the original image is not required.

Hereinafter, the operation of the present invention will be explained in detail by way of examples.

Embodiment FIG. 1 is a block diagram showing the configuration of an embodiment of the laser plate making apparatus of the present invention.

This laser plate making device includes a reading section 1, a plate making section 2,
It is comprised of a control section 3 that controls the operations of both of these sections.

The reading section 1 includes a main scanning mechanism consisting of a reading drum 11 that rotates around an original image, and a reading laser light source 12.
- A sub-scanning mechanism equipped with a reading optical mechanism consisting of 1 reflecting mirrors 13 a, 13 b, 14° converging lens 15 and a photoelectric converter 16, and an electric motor 17 that moves the 9 reflecting mirrors 14 in the axial direction of the reading drum 11 It is composed of.

On the other hand, the plate-making section 2 includes a main scanning mechanism consisting of a plate-making drum 21 that rotates around a plate-making material, and a plate-making laser light source 2.
21 and an optical mechanism for plate making consisting of reflecting mirrors 23a, 23b, 24 and a converging lens 25.

It is comprised of a sub-scanning mechanism equipped with an electric motor 27 that moves the reflecting mirror 24 in the axial direction of the plate-making drum 21.

The electric motor 30 rotates the plate-making drum 21 pivoted thereon at a predetermined speed, and at the same time rotates the nine rotation direction switching machine 31.
The reading drum 11 is also rotated via the shaft 32. The rotational direction switching device 31 is configured to be able to select the rotational direction of the prepress drum 21 to be either the same direction as the rotational direction of the reading drum 11 or the opposite direction. Such a rotation direction switching device 31 may be realized by a combination of gears, etc., or may be realized by a separate electric motor that selectively rotates in the same direction or in the opposite direction in synchronization with the rotation speed of the electric motor 30. Good too.

The control section 3 selects the two rotation directions by issuing a command to the nine rotation direction switching machine 31. Further, the control unit 3 controls the electric motor 30 based on the speed detected by the one-rotation encoder 33.
control the rotation speed of the Furthermore, the control section 3 controls the reading section l.
and controls the operations of the main scanning mechanism, sub-scanning mechanism, and optical mechanism of the plate making section 2.

A laser beam emitted from the reading laser light source 12 passes through nine reflecting mirrors 13a, 13b, and 14, is converged by a converging lens 15, and irradiates the original image wound around the reading drum 11. A photoelectric converter 16 converts the reflected light with an intensity corresponding to the brightness and darkness of the irradiated area of the original image into an electrical signal having a large and small amplitude. This electrical signal is used as a read signal.

The signal is supplied to the control unit 3. The control unit 3 transmits the reading signal to 2
This binary read signal is used to drive the laser light source 22 for plate making.

The laser beam emitted from the plate-making laser light source 22 passes through nine reflecting mirrors 23a, 23b, and 24, and then enters the converging lens 2.
5, and is irradiated onto the plate-making material wound around the plate-making drum 21. This plate making material.

It is made of a flexible material such as plastic or rubber with a thin metal coating or a single piece of plastic or rubber. The areas on the plate-making material that are irradiated with the high-energy-density laser beam reach high temperatures, causing the metal coating and plastic surface to evaporate, forming recesses. In this way, an uneven pattern corresponding to the brightness and darkness of the original image is formed on the plate-making material.

As shown in FIG. 1, the main scanning direction when both the reading drum 11 and the plate-making drum 21 rotate clockwise when viewed from the left in FIG. 1 is taken to be the X direction. Also 2 reflecting mirrors 14
and 24 move from right to left in the figure, the sub-scanning direction is taken as the Y direction.

Furthermore, it is assumed that the main scanning direction and the sub-scanning direction of the reading drum 11 are fixed to the above-mentioned X direction and Y direction, respectively. In this case, the original image wound around the reading drum 11 is subjected to main scanning from left to right and sub-scanning from top to bottom, as shown in FIG. 3(A).

■ When only the main scanning direction of the plate-making drum is reversed from that of the reading drum The above condition is achieved by operating the rotation direction switching device 31 to change the rotation direction of the plate-making drum 21 to the rotation direction of the reading drum 11. This is achieved by reversing the direction.

In this case, the second plate-making material on the plate-making drum 21 is
As shown in Figure (A), main scanning from right to left and sub-scanning from top to bottom are performed, and the plate making shown in Figure 2 (A) is performed based on the original image a shown in Figure 3 (A). C is created. This plate making C is for the original picture A.

The figure is line symmetrical in the sub-scanning direction Y, and is the original image a turned upside down.

■, When only the sub-scanning direction of the plate-making drum is reversed from that of the reading drum The above condition is achieved by reversing the rotating direction of the electric motor 27 of the sub-scanning mechanism and moving the 1 reflecting mirror 24 from left to right in Fig. 1. This is achieved by moving the

In this case, the second plate-making material on the plate-making drum 21 is
As shown in Figure (B), main scanning from left to right and sub-scanning from bottom to top are performed, and the plate making shown in Figure 2 (B) is performed based on the original image a shown in Figure 3 (A). d is created. This plate making d is for the original picture a.

This is a line-symmetric figure with respect to the main scanning direction X.

(2) When the main scanning direction and the sub-scanning direction of the plate-making section are both reversed to the reading section.The above condition is achieved by operating the transmission 31 to
This is realized by reversing the rotational direction of the reading drum 11, the rotational direction of the electric motor 27 of the sub-scanning mechanism, and moving the reflecting mirror 9 from left to right in FIG. Ru.

In this case, the second plate-making material on the plate-making drum 21 is
As shown in Figure (C), main scanning from right to left and sub-scanning from bottom to top are performed, and based on the original image a shown in Figure 3 (A)), The plate-making e shown is created. This plate making e is for the original picture a.

This is a point-symmetric figure with respect to the point where the main scanning direction X and the sub-scanning direction Y intersect.

As described above, main scanning is performed by rotating the drum.

Although we have shown an example of a configuration in which sub-scanning is performed by moving a reflecting mirror in the axial direction of the drum, it is also possible to arrange both the original drawing and the plate-making material on a flat surface and use a reflecting mirror such as a polygon mirror. It may also be configured to perform main scanning and sub-scanning.

Although the configuration in which the original image is read based on the amount of reflected light has been exemplified, it may be configured to read the original image based on the amount of transmitted light.

Although a configuration in which a laser light source is used as the light source for reading the original image has been exemplified, a non-coherent light source such as a single light emitting diode may also be used.

Effects of the Invention As explained in detail above, the laser plate making apparatus of the present invention is configured such that at least one of the main scanning direction and the sub scanning direction of the plate making section can be selected in the direction opposite to that of the reading section. On the other hand, when the main scanning direction is reversed, reverse plate making can be made without using a large capacity memory as in the conventional example, and the overall cost of the apparatus is reduced.

Further, when the sub-scanning direction is also reversed for a complex figure that is difficult to draw, the plate of the target figure can be easily created. For example, it is effective when converting a figure drawn in the first quadrant to figures in the second to fourth quadrants.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a conceptual diagram for explaining the operation of the laser engraving apparatus shown in Fig. 1, and Fig. 3 explains the problems of the prior art. This is a conceptual diagram for 1. Reading section, 2. Prepress making section, 3. Control section. 11...Drum for reading, 12...Laser light source for reading, 14...Reflector, 17...Electric motor for sub-scanning, 21...
・Drum for plate making, 22... Laser light source for plate making, 24.
・Reflector, 27: Sub-scanning motor, 30: Main-scanning motor, 31: Rotation direction switching machine. Patent Applicant NEC Corporation Representative Patent Attorney Toshihiko Kashii Figure 2 (A) (B) (C) Figure 3 (A) (B)

Claims (1)

[Scope of claims] A reading scanning mechanism that scans a reading light beam irradiated onto an original image in a main scanning direction and a sub-scanning direction; and a laser beam that forms irregularities on a plate-making material according to the brightness and darkness of the original image. a plate-making scanning mechanism that scans in the main scanning direction and the sub-scanning direction; and at least one of the main scanning direction and the sub-scanning direction of the plate-making scanning mechanism in the main scanning direction and the sub-scanning direction for reading, respectively. A laser engraving device characterized by comprising means for selecting the opposite direction.