JPH0924594A - Digital plate making machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital plate making machine which is suitable for making a color printing master and characterized by a short plate making time and the relatively simple structure of an exposure part. SOLUTION: A digital plate making machine which, after charging the photosensitive layer of a master plate X, forms an electrostatic latent image in the photosensitive layer by a laser scan unit 10 is equipped with movable tables 7, 9 which can move in the subordinate scanning direction of a nearly horizontal exposure stage A which can accurately position and fix the master plate X. The laser scan unit 10 with a laser beam α directed downward is mounted on the movable tables 7, 9, and a charger B extending perpendicularly to the subordinate scanning direction is fixed in the lower part of the movable tables 7, 9 which come closer to the exposure stage side than the laser scan unit 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making machine for producing a master for printing, and more particularly to a digital plate making machine using a master plate having a foil plate such as an aluminum plate as a base material.

[0002]

2. Description of the Related Art As is well known, in a plate making machine for producing an image master used in a printing machine, a master paper having a surface of a synthetic resin sheet coated with a photosensitive material such as zinc oxide is used. Master paper has considerable expansion and contraction depending on temperature and humidity. Therefore, when a plurality of color separation masters made of master paper is used in a printing machine that performs color printing, color misregistration may occur due to expansion and contraction of the master paper.

For this reason, recently, a master plate having an aluminum plate as a base material which is not affected by temperature conditions and humidity has been provided, but since this master plate is hardly affected by temperature conditions and humidity conditions. , Has the potential to be used as a color separation master for color printing.

[0004]

When a master paper or a master plate is used to make an image stored in a computer or the like, a laser scan unit having a polygon mirror is used. It is necessary to charge the photosensitive layer before the main scanning of the layer. Therefore, in the conventional digital plate making machine using the laser scan unit, the charging scan in the sub-scanning direction by the charger and the sub-scanning in the same direction of the laser scan unit are separately performed. Not only is it complicated, but in addition to the time required for electrostatic latent image formation by the laser scan unit, the charging time in the sub-scanning direction by the charger is also required, and the time required for plate making is long.

In view of the problems of the conventional digital plate making machine as described above, the first object of the present invention is suitable for producing a master for color printing, the plate making time is short, and the structure of the exposure section is comparative. To get a simple digital platemaking machine.

A second object of the present invention is to provide a digital plate making machine which can achieve the first object, and which can easily adjust the initial position of the master plate in the main scanning direction with respect to the photosensitive layer. It is in.

[0007]

According to the present invention, the first object of the present invention is to digitally form an electrostatic latent image on a photosensitive layer of a master plate after charging the photosensitive layer with the laser scanning unit. In the plate-making machine, a movable base that can move in the sub-scanning direction of a substantially horizontal exposure stage that can accurately position and fix the master plate is provided, and the laser scan unit in which the laser beam is directed downward is mounted on the movable base. Achieved by a digital plate-making machine in which a charger extending in a direction perpendicular to the sub-scanning direction is fixed to the lower part of the movable table closer to the exposure stage side than the laser scanning unit, facing the photosensitive layer. To be done. According to the present invention, the second object is, in the digital plate making machine capable of achieving the first object, the charger is fixed to a first movable table movable in the sub-scanning direction of the exposure stage. The laser scanning unit has a structure in which the laser scanning unit is fixed to a second movable base that can be adjusted in position along a guide rod of the first movable base extending in a scanning direction perpendicular to the sub-scanning direction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show the whole of the digital plate making machine according to the present invention, and the whole of the digital plate making machine and the plate making process will be described with reference to the drawings.

A horizontal installation base 3 is provided at a substantially middle portion in the vertical direction of the machine body frame 2 inside the plate-making machine body, which is entirely covered with a light-shielding panel 1, and a master 3 is provided on the right side of the installation base 3. An exposure stage A having a pair of positioning pins 4A and 4B capable of accurately positioning and fixing the plate X is arranged. Therefore, the operator has the same positioning pins 4A, 4
After manually positioning the master plate X on the surface of the exposure stage A using B, the slide cover 5 covering the upper part of the exposure stage A can be closed to prepare the master plate X for exposure.

A pair of parallel guide rods 6A and 6B extending in the left-right direction of FIG. 1, that is, the sub-scanning direction are fixed in front of and behind the installation table 3, and these guide rods 6 are arranged.
A laser scanner C having a charger B for charging the photosensitive layer of the master plate X is movably supported by A and 6B in the sub-scanning direction. The laser scanner C includes the guide rod 6
A first movable table 7 that can be moved in the sub-scanning direction by A and 6B is provided, and the guide rod 6 is provided at the lower front end of the first movable table 7.
Charger B extending in the main scanning direction perpendicular to A and 6B
Is fixed, and therefore the first movable table 7 is moved forward in the sub-scanning direction, the photosensitive layer of the master plate X positioned on the exposure stage A, which will be described in detail later, by the charger B fixed downward. Is charged before exposure.

Further, two guide rods 8A and 8B are supported on the upper part of the first movable table 7, and the guide rods 8A and 8B are
Second movable table 9 whose position can be adjusted in the main scanning direction along 8B
A laser scanning unit 10 capable of irradiating the laser beam α downward is mounted on the. That is, inside the laser scanning unit 10, a polygon mirror 10a for main scanning the laser beam α in the main scanning direction perpendicular to the sub-scanning direction, that is, the direction perpendicular to the paper surface of FIG. The beam α is applied to the photosensitive layer of the master plate X positioned on the exposure stage A through the exposure slot 11 formed in the first movable table 7 in the main scanning direction. In order to adjust the initial position, the lock screw 12 screwed into the sliding sleeve 9a of the second movable table 9 which is slidably fitted to one of the guide rods 8A and 8B is loosened to move the first movable table 7 in the main scanning direction. After adjusting the position of the laser scan unit 10, the lock screw 12 may be tightened. Although digitized image information is supplied to the laser scan unit 10 from a computer (not shown) or the like, when manufacturing a master for color printing, the laser scan unit 1 is used.
Image information is provided to 0 for each decomposition dye, and a plurality of masters of the same image are created for each decomposition dye.

In order to drive the laser scanner C, two pairs of timing sprockets 13A, 13B, 14A, 14B facing each other in the sub-scanning direction are installed in front of and behind the above-mentioned installation base 3, and the timing of each of these pairs. Sprocket 13
Endless timing belts 15A and 15B are stretched between A, 13B, 14A and 14B. The timing belts 15A and 15B are the timing sprocket 13
A, 13B, 14A, 14B synchronous shaft 16,1 connecting between
7 is driven synchronously by a sub-scanning drive gear 18 (FIG. 2), and a joint piece 7a extending from the first movable table 7 of the laser scanner C is fixed to a part of these timing belts 15A and 15B. To be done. Therefore, the sub-scanning drive gear 18
The exposure stage A is moved forward from the standby position (initial position) indicated by the solid line to the sub-scanning end position indicated by the phantom line by the forward rotation of the above. Becomes a latent image.

Further, the exposure stage A is provided with an exposure frame 20 which can be tilted about a pivot shaft 19 arranged on the side opposite to the standby position of the laser scanner C. The exposure frame 20 and the machine frame 2 are tilted. The tilting cylinder 21 provided therebetween can tilt from the exposure position shown by the solid line to the master discharge position shown by the phantom line. The exposure stage A includes a horizontal perforated surface plate 22 that covers the upper surface of the exposure frame 20.
A pair of positioning pins 4A and 4B capable of precisely positioning the master plate X are arranged on the surface of the non-image portion of the porous platen 22.

Below the perforated plate 22 is a perforated plate 22.
A vacuum box 23 capable of exerting a vacuum pressure is fixed to the master plate X through a large number of vacuum suction holes 22a, and belt arms 25A and 25B which are rotatable around a fulcrum shaft 24 on both sides of the exposure frame 20. Between the pulleys 26 at the tips of the belt arms 25A and 25B, the pulley 27 of the pivot shaft 19, and the tension pulley 28 at the lower portion of the exposure frame 20. A plurality of conveyor belts 29 that surround 23 are suspended. That is, on the surface of the porous platen 22, a plurality of retreat grooves 22b in which a part of these conveyor belts 29 can be settled are formed, and as shown in FIG.
An upper stopper 30 and a lower stopper 31 installed on the machine body frame 2 face the belt arms 25A and 25B.

Therefore, when the exposure stage A is in the exposure position shown in FIG. 1, the upper stopper 30 rotates the belt arms 25A and 25B counterclockwise as shown in FIG. The transport belt 29 is the perforated surface plate 22.
Since it settles in the retreat groove 22b, the master plate X can be adsorbed to the surface of the porous platen 22 regardless of the conveyor belt 29 while maintaining the flatness by the vacuum pressure of the vacuum box 23.
On the other hand, the exposure stage A is moved by the tilting cylinder 21 as shown in FIG.
When moved to the master discharge position shown in (c), the belt arms 25A and 25B are rotated clockwise by the lower stopper 31, and the respective conveyor belts 29 are lifted above the surface of the perforated platen 22 to raise the master plate X. Transfers to the conveyor belt 29,
The exposed master plate X is pulled by the transport roller 32 by the feeding movement of the transport belt 29 due to the rotation of the pivot shaft 19.

FIG. 3 shows the details of a positioning unit for operating the positioning pins 4A and 4B provided on the exposure stage A. The positioning unit is provided with a support bracket 33 fixed to the lower part of the perforated platen 22, and supports this. With respect to the bracket 33, the core rod 34 facing up and down
The electromagnetic solenoid 34 having a is fixed. The base ends of the positioning pins 4A and 4B described above are fixed to the tip of the core rod 34a via a joint sleeve 35, and the positioning pins 4A and 4B guided in the vertical direction by a thrust sleeve 36 are moved upward by a compression spring 37. Be energized.

Therefore, the tip ends of the positioning pins 4A, 4B can be projected onto the surface of the perforated surface plate 22 by the compression spring 37 when the exposure stage A is at the exposure position. The master plate X having a positioning hole of the same diameter as can be accurately positioned on the surface of the porous platen 22. Further, when the exposure stage A is set to the master discharge position shown by the phantom line, the electromagnetic solenoid 34
Is excited and the positioning pins 4A and 4B are retracted below the surface of the perforated platen 22, so that the master plate X becomes free and is fed to the conveyance roller 32 by the feeding movement of the conveyance belt 29.

Below the installation table 3 corresponding to the laser scanner C in the standby position, a plurality of process equipments for performing the subsequent plate making process of the latent imaged master plate X are incorporated. That is, immediately after the transport roller 32, the black frame removing unit D that removes charges other than the image portion on the surface of the master plate X is positioned, and the master plate X that has passed through the black frame removing unit D is transferred to the developing device E. Developing section entrance roller 3
9, the electrostatic latent image on the master plate X is toner-developed by the developer sprayed from the developer spray head 40 of the developing device E, and a visualized image is formed on the surface of the master plate X. .

After that, while the master plate X passes through the squeezing roller 41 of the developing device E, excess developer on the surface of the master plate X is removed, and the master plate X is heated by the feeding movement of the developing section outlet roller. While being sent to the fixing device F and passing through the heating and fixing device F, the master plate X is dried, and the toner image on the surface of the master plate X is heated and fixed. Then, the completed master is ejected to the ejection chute 43 by the rotational movement of the ejection roller 42 on the left side of the machine, and sent to the printing process.

Since the digital plate making machine according to the illustrated embodiment has the structure as described above, it can be used as a color image plate making machine for producing a plurality of masters by color-separating color images. That is, in plate making, the laser scanner C is placed in the standby position shown in FIG. 1, and the master plate X is manually moved by using the reproducible positioning pins 4A and 4B to open the aperture of the exposure stage A. A vacuum pressure is applied to the vacuum box 23 of the exposure stage A located on the surface of the surface plate 22, and the master plate X is fixed to the perforated surface plate 22 in a state in which the master plate X is kept flat by the suction of the vacuum suction holes 22a. Of course, the master plate X used for plate making for this color image
Is a master plate X if it is manufactured in the same lot.
Since the relationship between the positioning holes and the positioning pins 4A and 4B formed in 1) can maintain sufficient reproducibility, a color image without color misregistration can be printed by a plurality of masters manufactured in the plate making process described later.

When the slide cover 5 is closed and the start button is pushed, the laser scanner C is guided by the guide rods 6A and 6B by the feed motion of the timing belts 15A and 15B at a constant speed.
While moving in the sub-scanning direction, the photosensitive layer of the master plate X is charged by the charger B supported by the first movable table 7 of the laser scanner C prior to the main scanning of the image. At the same time, with the constant velocity movement of the laser scanner C in the sub-scanning direction, the laser beam α is main-scanned in the main-scanning direction from the laser scanning unit 10 through the exposure slot 11, and the photosensitive layer of the master plate X is scanned. Since the image pixels are main-scanned, the electrostatic latent image is formed on the entire photosensitive layer of the master plate X by the movement of the laser scanner C in the sub-scanning direction and the main scanning of the laser beam α in the main scanning direction. It will be. Therefore,
According to the structure of the illustrated embodiment, the process of charging the photosensitive layer of the master plate and the process of forming an electrostatic latent image on the photosensitive layer are performed simultaneously, so that the time required for plate making is shortened.

After the electrostatic latent image is formed, the exposure stage A is tilted counterclockwise about the pivot shaft 19 (FIG. 4).
(B)), the action of the vacuum pressure on the vacuum box 23 is stopped, and the electromagnetic solenoid 34 of the positioning unit is excited, so that the tips of the positioning pins 4A and 4B are perforated against the force of the compression spring 37. The master plate X is released from the exposure stage A because it is retracted below the surface of the board 22.

Then, immediately before the exposure stage A tilts to the master discharge position shown in FIG. 4C, the lower stopper 31 hits the belt arms 25A and 25B, and the conveyor belt 29 retracts due to the subsequent tilting of the perforated platen 22. The exposed master plate X is transferred onto the conveyor belts 29 after being exposed from 22b. Therefore, the master plate X is pulled by the transport roller 32 by the leftward feeding movement of the transport belt 29, and the black frame on the surface of the non-image portion of the master plate X is removed while passing through the black frame removal unit D. Then, the electrostatic latent image on the surface of the master plate X is developed with toner.

The master plate X from which the excess developing solution has been removed by the squeeze roller 41 is heated and dried when passing through the heating and fixing device F, and is completed on the discharge chute 43 by the discharge rotation movement of the discharge roller 42. The master is taken out. By repeating the plate making process as described above, 3 to 4 masters for each resolution pixel are made for one color image. However, since the image positions of these masters have a sufficient correspondence, Can be used for color printing.

[0025]

As is apparent from the above description, according to the present invention, since the charger is fixed to the first movable table, it is not necessary to provide a special drive mechanism for the charger, and the photosensitive layer is eliminated. The plate making time is shortened because the charging of the sheet and the main scanning by the laser scanning unit are simultaneously performed. Further, in the present invention, since the laser scanning unit is mounted on the second movable table whose position can be adjusted in the operation direction of the first movable table, there is an effect that the position adjustment in the main scanning direction with respect to the master plate becomes easy.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a digital plate making machine according to the present invention.

FIG. 2 is an overall cross-sectional view of the digital plate making machine substantially along the line 2-2 in FIG.

FIG. 3 is an enlarged cross-sectional view of a positioning pin of the digital plate making machine.

4 (a), (b) and (c) are operation explanatory views of an exposure stage of the digital plate making machine.

[Explanation of symbols]

 A exposure stage B charger C laser scanner X master plate α laser beam 6A, 6B guide rod 7 first movable table 8A, 8B guide rod 9 second movable table 10 laser scan unit 11 exposure slot 15A, 15B timing belt

Claims (2)

[Claims] 1. After charging the photosensitive layer of the master plate,
In a digital plate making machine that forms an electrostatic latent image on the same photosensitive layer by a laser scanning unit, a movable base movable in the sub-scanning direction of a substantially horizontal exposure stage capable of accurately positioning and fixing the master plate is provided. The laser scan unit with the laser beam directed downward is mounted on the lower part of the movable table which is closer to the exposure stage than the laser scan unit and extends in a direction perpendicular to the sub-scanning direction. A digital plate-making machine, characterized in that an electric device is fixed so as to face the photosensitive layer. 2. The charging unit is fixed to a first movable table of the exposure stage which is movable in the sub-scanning direction, and the laser scanning unit extends in the operation direction perpendicular to the sub-scanning direction. A digital plate making machine characterized by being fixed to a second movable table whose position can be adjusted along a guide bar of the movable table.