JPH08234445A - Developing device for waterless planographic printing plate - Google Patents

Abstract

PURPOSE: To easily perform developing processing at a high speed by rotating a brush roll in a developing machine in the same direction as the carrying direction of a printing original plate, reciprocating it in a roll shaft direction and rotating a brush roll in a post-processing machine in the opposite direction, thereby removing a silicone rubber layer. CONSTITUTION: The printing original plate is rubbed by the brush rolls 8 and 9 arranged to uniformly come into contact with the printing original plate, rotating in the opposite direction to each other and respectively rocking in the shaft direction, so that the silicone rubber layer of an image line part is removed. As for the brush rolls 8 and 9, at least one roll rotating in the same direction as the carrying direction of the printing original plate and at least one roll rotating in the opposite direction are necessitated, and it is desirable to rotate the 1st brush roll 8 in the same direction as the carrying direction and the 2nd brush roll 9 in the opposite direction. Then, it is desirable to rock at least one of the brush rolls 8 and 9, more desirably, both of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for a waterless lithographic printing plate, and more particularly to an improvement in a developing device for a waterless lithographic printing plate having a silicone rubber layer backed by a substrate as an uppermost layer.

[0002]

2. Description of the Related Art Waterless lithographic printing plates having a silicone rubber layer lined on a substrate as an uppermost layer are disclosed, for example, in JP-B-46-16044, JP-A-50-50102, and JP-A-55-59466. It is proposed in the Gazette and the like.

These waterless planographic printing plates are subjected to image exposure processing by a known method and developed. When developing is carried out using an automatic developing machine, a plate-shaped printing original plate is conveyed by rolls. A developing device is used in which the brush roll is rotated so that the printing original plate is rubbed in the same direction as the advancing direction at the contact portion of the one to four brush rolls, and the silicone rubber layer in the image area is removed. It is common.

As described above, the reason why the brush roll is used for developing the waterless planographic printing plate is that the silicone rubber layer on the surface is generally insoluble and therefore needs to be rubbed by a mechanical force. In addition, it is the most practical means to meet this purpose. Further, the reason why the brush roll is rotated so as to rub it in the same direction as the traveling direction of the printing original plate is to prevent the tip of the printing original plate from being splashed by the brush roll.

[0005]

In the case of such an apparatus, there is a problem that the shape of halftone dots to be developed depends on the rubbing direction of the brush roll, and uniform halftone dots cannot be obtained. Many. That is, within the halftone dot, the silicone rubber layer is almost completely removed on the downstream side in the rubbing direction of the brush roll, whereas the silicone rubber layer tends to remain on the upstream side, particularly at the edge of the halftone dot. As a result, the tone reproducibility is deteriorated even during printing, and a color defect occurs, which causes serious defects.

Therefore, an apparatus described in Japanese Patent Laid-Open No. 60-59351 has been proposed as an apparatus for improving the drawback.

This apparatus uses two or more brush rolls when rubbing and developing the printing original plate, and at least one of the brush rolls is rubbed by rotating in the opposite direction to the other brush rolls. The silicone rubber layer at the edge of the halftone dot is removed.

However, in the case of this apparatus, if the brush roll which is rotated in the direction opposite to the conveying direction of the printing original plate is made to have a strong rubbing force, the printing original plate is repelled, so that the rubbing force of the brush roll must be weakened. ,
As a result, especially for thick printing plates with a silicone rubber layer,
There is a problem that the silicone rubber layer at the edge of the halftone dot is not uniformly removed and remains. Further, there are problems that the defective dot shape due to the non-uniformity of the brush material cannot be eliminated and that the silicone rubber layer is not uniformly removed and remains even at high speed development.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention provides a novel developing device for developing a waterless planographic printing plate simply, reliably and at high speed. Is.

That is, the present invention provides a waterless planographic printing plate having a silicone rubber layer backed by a substrate as an uppermost layer,
In a developing device for a waterless lithographic printing plate in which the silicone rubber layer is rubbed with a brush roll to develop while being sequentially conveyed into a developing machine and a post-processing machine, a brush roll is provided in the developing machine and the post-processing machine. The brush roll is rotated in the same direction as the transport direction of the waterless planographic printing plate and is reciprocally moved in the roll axial direction, and the brush roll in the post-processing machine is rotated in the opposite direction to the transport direction so that the image area is changed. A developing device for a waterless planographic printing plate characterized by physically removing a silicone rubber layer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing an embodiment of a developing device for a waterless planographic printing plate according to the present invention.

The waterless lithographic printing plate used in the present invention has a silicone rubber layer backed by a substrate as an uppermost layer, and a substrate, a photosensitive layer and a silicone rubber layer laminated in this order, a substrate, Examples thereof include a laminate of photosensitized silicone rubber layers in this order, and a cover film may be provided on the silicone rubber layer.

The substrate has a thickness of about 10 microns to 2
mm, preferably about 50 to 500 microns of paper, plastic film or sheet, elastic sheet such as rubber, metal plate such as aluminum, or laminated composite material of paper and plastic film, metal plate and rubber sheet, and the like. A material obtained by subjecting these to a surface treatment such as plating or coating is used.

The photosensitive layer is a layer having a property of being photocured or solubilized by being irradiated with an active ray. This layer is evenly applied to the substrate, and its thickness is optional as long as it is in intimate contact with the substrate, but preferably about 100.
Submicron or less, and more preferably about 1 to 10 microns are more useful. If necessary, it is also useful to provide an anchor coat between the substrate and the photosensitive layer to improve adhesion between the photosensitive layer and the substrate or to prevent halation. As the photosensitive substance, a known substance such as a composition containing a photopolymerizable monomer or oligomer, a photocurable diazo compound or an azide compound, a compound containing a quinonediazide group and the like can be used.

The silicone rubber layer has a thickness of 0.5.
~ 100 microns, preferably about 1-10 microns,
A known silicone rubber known as room temperature curable type or low temperature curable type is suitable. These silicone rubbers contain a linear organic polysiloxane as a main component, and a crosslinking agent, a catalyst and the like are generally added. The silicone rubber layer in the present invention may have photosensitivity and can be obtained by chemically reacting or mixing an organic polysiloxane compound with a known photosensitizing compound. .

The brush roll used in the present invention is generally one in which a brush material such as a plastic thread or animal hair having a diameter of 20 to 500 microns is radially implanted in the core of plastic or metal, but A brush material embedded in a base material such as a sheet, a film, or a cloth may be wound around a core, and further, one in which the brush material is implanted in a plastic or metal groove material is attached to the core. Either may be used.

A developing device according to the present invention for a printing plate comprising the above components will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing an example of an automatic developing machine using the developing device according to the present invention. In the figure, the printing original plate 1 that has been subjected to the image exposure process is inserted into the developing device main body 3 from the carry-in table 2, is subjected to the developing process, and is then discharged to the carry-out table 4. The developing solution sent by the pump 6 is sprayed from the spray nozzle 7 onto the printing original plate in the developing machine. The developer swells the silicone rubber layer, or weakens the adhesive force between the silicone rubber layer in the image area and the lower layer, thereby facilitating the removal of the silicone rubber layer in the image area and at the same time removing the removed silicone rubber. Generally, it has a function of washing off rubber pieces from the printing original plate. Next, the printing original plate is rubbed by brush rolls 8 and 9 which are arranged so as to be in uniform contact therewith and which rotate in mutually opposite directions and are swingable in the axial direction, respectively. Is excluded. Reference numeral 10 denotes a printing plate precursor support mechanism provided at a position facing the brush roll so that the printing plate does not escape from the brush roll. The support mechanism 10 may be a cylindrical object, but a plate-like object as shown in the figure is used. As the automatic developing machine, not only the above-mentioned basic mechanism but also a pre-processing machine, a post-processing machine, a water washing machine, a drying machine, etc. may be used, and a brush roll is also dispersedly arranged in the pre-processing machine, the post-processing machine or the water washing machine. May be. The brush roll used in the present invention requires at least one that rotates in the same direction as the transport direction of the printing original plate and at least one that rotates in the opposite direction, but the first brush roll is the transport direction. Rotate it in the same direction as
It is preferable to rotate the brush rolls after the th direction in the opposite directions. Moreover, it is necessary to rock at least one of these brush rolls. More preferably, both of the brush rolls 8 and 9 should be oscillated.

If the function of the brush roll is divided into the function of roughly removing the silicone rubber layer at the halftone dot portion and the function of finish-removing the slightly remaining silicone rubber layer at the halftone dot edge portion, the former function is It is better to rotate the brush roll made of a stiff brush material quickly, but if this is rotated in the direction opposite to the conveying direction of the printing original plate, there is a risk that the leading edge of the printing original plate will rise. On the other hand, the latter function is satisfied by slowly rotating a brush roll made of a brush material having a weak stiffness, so that the above-mentioned risk can be reduced to a level where there is practically no problem. Therefore, as the first brush roll, for example, an outer diameter of 100 to 200 obtained by implanting nylon 6/10 having a single yarn diameter of 200 to 400 microns in a bristle length of 10 to 20 mm is used.
Using a brush roll of mm, the silicone rubber layer is roughly removed by rotating it at a speed of 200 to 500 rpm for rubbing in the same direction as the direction of conveyance of the printing original plate, and slightly at the halftone dot edge portion. The brush that finishes and removes the remaining silicone rubber layer is, for example, nylon 6.10.
~ 250 micron single yarn diameter 15 ~ 30m
It is effective to use a brush roll having an outer diameter of 50 to 100 mm planted in m and rotate this at a speed of 50 to 500 rpm for rubbing in the direction opposite to the conveying direction of the printing original plate.

The swinging of the brush roll causes the brush roll to reciprocate 50 to 400 times per minute with a swinging width of 5 to 100 mm in the direction perpendicular to the transport direction of the printing original plate, that is, in the roll axial direction. As a method of rocking, a method of using a cam, a link, a shaft or the like for rocking an ink applying roller of a printing machine, or cutting a screw groove inside the roll is generally used. The specifications, rotation, and rocking conditions of the brush roll are determined by the ease of peeling the silicone rubber layer, the ease of scratching the silicone rubber layer, and the rigidity of the printing original plate, and are not limited to the above use examples. Not something.

[0022]

EXAMPLES Next, the present invention will be described more specifically by way of examples.

Example 1 Commercial positive type Toray waterless planographic printing original plate (length 1030 m
m, width 980 mm) is subjected to a halftone dot exposure treatment by a known method to peel off the polyester film, and then this is composed of a pretreatment machine, a developing machine and a post-processing machine. Development processing was performed using an automatic developing machine having one brush roll each. That is, a pretreatment machine for spraying polypropylene glycol on the printing original plate, then, while spraying water on the printing original plate, made of nylon 6.10.
With a brush roll with a length of 1160 mm and an outer diameter of 130 mm, a single yarn with a diameter of 200 microns was planted so that the length of the bristle was 15 mm, and 3 minutes per minute in the same direction as the direction of travel of the printing original plate.
Rotating 00 times and reciprocating 120 minutes per minute, swing width 30 mm
Shake the machine and rub it, and finally spray an aqueous solution such as dye and surfactant onto the printing original plate, and make a single yarn of nylon 6.10. An automatic developing machine consisting of a post-processing machine was used in which a brush roll having a length of 1160 mm and an outer diameter of 100 mm was planted so that it was rotated 180 minutes per minute in the direction opposite to the traveling direction of the printing original plate and rubbed the same. The transport speed was 40 cm / min. As a result, uniform halftone dots were obtained without bouncing the printing plate and leaving no silicone rubber layer at the edges. High-quality printed matter was obtained during printing.

Example 2 In Example 1, the brush roll of the post-processing machine was changed to 120 per minute.
It swings back and forth with a swing width of 30 mm to achieve even higher speeds of 60 mm.
Development was carried out at a conveying speed of cm / min. As a result, it was possible to obtain a uniform halftone dot in which the silicone rubber layer at the edge portion was also removed, and it was possible to obtain a high-quality printed matter at the time of printing.

[0025]

According to the present invention, in developing a waterless lithographic printing plate precursor, a uniform halftone dot having no directivity can be reliably obtained, and an automatic developing machine capable of high-speed development can be obtained.
As a result, the printed matter can maintain a stable ink density during printing, and a high-quality printed matter excellent in tone reproducibility can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an automatic developing machine according to the present invention.

[Explanation of symbols]

 1: Printing original plate 2: Carry-in table 3: Developing machine main body 4: Carrying-out table 5: Roll 6: Pump 7: Spray nozzle 8, 9: Brush roll 10: Support mechanism

Claims (8)

[Claims] 1. A water for rubbing and developing a waterless planographic printing plate having a silicone rubber layer backed by a substrate as a top layer in a developing machine and a post-processing machine while rubbing the silicone rubber layer with a brush roll. In a lithographic printing plate developing device, a brush roll is provided in the developing device and the post-processing device,
The brush roll in the developing machine is rotated in the same direction as the transport direction of the waterless planographic printing plate and is reciprocally moved in the roll axial direction, and the brush roll in the post-processing machine is rotated in the opposite direction to the transport direction. A developing device for a waterless planographic printing plate, characterized in that the silicone rubber layer in the line portion is physically removed. 2. The waterless lithographic printing plate developing apparatus according to claim 1, further comprising means for reciprocating a brush roll in a post-processor in a roll axis direction. apparatus. 3. The waterless lithographic printing plate developing apparatus according to claim 1, wherein a cam is used for the reciprocating mechanism of the brush roll. apparatus. 4. The waterless planographic printing plate developing apparatus according to claim 1, wherein the width of the reciprocating motion of the brush roll is in the range of 5 to 100 mm. Lithographic printing plate developing device. 5. The waterless lithographic printing plate according to claim 1, wherein the brush material of the brush roll is a plastic thread. Developing device. 6. The developing device for a waterless planographic printing plate according to claim 5, wherein the brush roll on the upstream side in the transport direction has a diameter of a brush material larger than that of the brush roll on the downstream side in the transport direction. A waterless planographic printing plate developing apparatus characterized by the above. 7. The waterless lithographic printing plate developing apparatus according to claim 5 or 6, wherein the diameter of the brush material of the brush roll on the upstream side in the transport direction is in the range of 20 to 400 microns, and The diameter of the brush material of the brush roll on the downstream side is in the range of 50 to 250 microns. 8. The waterless lithographic printing plate developing apparatus according to claim 5, wherein a support mechanism for preventing escape of the waterless lithographic printing plate is provided at a position facing the brush roll. A waterless planographic printing plate developing device characterized by being provided.