JPH0614184B2 - Method for developing a photosensitive lithographic printing plate which improves the uniformity of development - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a development processing method for a photosensitive lithographic printing plate (hereinafter referred to as PS plate), and more specifically, an unused development for each PS plate. The present invention relates to a PS plate developing method suitable for an automatic developing machine for supplying a liquid to perform development.

[Prior Art and Background of the Invention]

When processing many exposed PS plates, it is common to use an automatic processor.

When processing the exposed PS plate in an automatic developing machine, the PS plate is transported horizontally and sprayed with a developing solution to develop it, or the PS tank is filled with a large amount of developing solution. A method is used in which a plate is curved and immersed while being conveyed to be developed. In any of these processing methods, it is necessary to prepare a large amount of developing solution to process one PS plate. In addition, in order to economically utilize the developer, it is recycled and reused.During that time, in addition to deterioration of the developer due to processing, deterioration of the developer due to absorption of carbon dioxide gas from the air occurs, and often the deteriorated developer is It has to be replaced, and management of the development work is very troublesome.

For the purpose of improving the above-mentioned drawbacks, when a PS plate is treated with a large amount of recirculating and reused developer, a method is known in which a replenisher is replenished to keep the development process stable.
No. 55-115039, No. 58-95349, etc. Even with such a replenishment method, although the frequency of liquid exchange is reduced, it is necessary to perform liquid exchange, and the problem of replenishment accuracy and the replenishment problem due to the difference in product type between PS plates could not be solved. Further, a replenishing device is required on top of it, and not only the replenishing device itself is expensive, but also the replenishing device needs to be adjusted and maintained.

A processing apparatus for eliminating the troublesomeness of the replenishing method is disclosed in Japanese Patent Laid-Open No. 55-32044. This is equipped with a developer diffusion plate near the photosensitive material transfer path in the automatic developing machine to stretch the developer applied on the PS plate surface. As for the processing method, since the PS plate to be conveyed is not always horizontal and is slightly distorted up and down, the developer amount is likely to be non-uniform, development unevenness is likely to occur, and the PS plate to be processed and the developer diffusion plate are processed. There is a drawback that it takes time to adjust the gap between the and, especially when a small amount of developing solution is dropped directly onto the PS plate surface, a development speed difference occurs between the dropping part and the non-dripping part, and after passing through the development diffusion plate. However, this difference remains, resulting in uneven development, which may result in an unfavorable printing plate.

We have already developed and applied for a method and apparatus for PS plate development that can improve such defects and enable stable development using a small amount of developing solution (Japanese Patent Application No. 61-82900). However,
We have found that the technology of developing with a small amount of developer has a problem of developing failure at the tip of the PS plate, which is presumed to be due to lack of developer, and we have developed a technology to solve this problem. Developed and already applied (Japanese Patent Application No. 61-101681)
issue). This invention holds a developer film on a PS plate during a part of the developing period, and forms a developer reservoir thicker than the developer film at least at the tip of the PS plate during another part of the developing period. It is a thing.

The present invention relates to improvements in details of the invention. That is, when the PS plate is slid on a slanted guide plate to convey the PS plate in an ascending direction in order to form the developer reservoir, the back surface of the PS plate is rubbed by the guide plate and streaks occur. -Like scratches, and if the scratches are deep, the shape of the surface is also affected and good halftone dot reproduction cannot be obtained in printing, and when forming the developer pool, the developer is The present invention relates to a technique for improving the drawback that the aluminum material of the support is eroded and eluted to gel on the back surface and adheres to the PS plate to cause stains.

[Object of the Invention]

It is an object of the present invention to provide a developing method in which the development failure of the leading end portion of the PS plate in the method of developing a PS plate using a relatively small amount of the developer as described above is improved. Another development method is to provide a development method in which the occurrence of scratches on the back surface of the PS plate is improved.

[Structure of Invention]

An object of the present invention is to provide a method for developing a photosensitive lithographic printing plate which automatically conveys and develops the photosensitive lithographic printing plate using an automatic processor, which is formed by two flexible plate materials. After supplying a substantially unused developing solution for each photosensitive lithographic printing plate to be processed from the slit of the developing solution supply member having a slit at the lower end, the inclined roller is conveyed upward in the conveying direction. And a continuous developing solution pool is formed on the photosensitive lithographic printing plate in the carrying width direction.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view showing an example of an apparatus for carrying out the present invention.

In FIG. 1, reference numeral 1 is a pair of transport rollers for nipping the PS plate 2 for transport, and 3 is a pressing roller for keeping the PS plate 2 at a proper transport position. Reference numeral 4 denotes an inclined roller, which is provided so that the PS plate 2 supplied with the developer is conveyed in a direction in which the PS plate 2 rises in the conveying direction. Reference numeral 5 denotes a developer tank, and the developer contained therein is sent to the developer supply pipe 6 by the pump 5a. A developer supply member 7 has a slit formed at its lower end by two flexible plate materials, and the developer flowing down from the developer supply pipe 6 is supplied to the PS plate 2 through this slit. To be done. When the PS plate 2 does not pass through the lower end of the developer supply member 7, the lower end of the developer supply member 7, that is, the lower end of the slit is hung down by gravity due to the flexibility of the two plate materials forming the slit. And a concave portion in the horizontal direction (hereinafter referred to as “width direction”) that is in contact with the developing unit roller 8 and is orthogonal to the conveying direction formed by the lower end of the developer supply member 7 and the developing unit roller 8, and the conveying unit. When the PS plate is in this position, a pool 9 of the developer is formed in a widthwise recess formed in the contact portion between the lower end of the developer supply member 7 and the PS plate 2. It is preferable that each of the above rollers is provided so that the back surface of the PS plate does not contact the developing section roller except for the front end and the rear end thereof.

The PS plate 2 to be conveyed first has its tip end in the liquid pool 9 of the recess formed by the developer supply member 7 and the developing section roller 8. After the leading edge of the PS plate 2 passes through the developer pool 9 formed in the widthwise recess formed by the developer supply member 7 and the developing unit roller 8, the PS plate 2 and the developer supply member 7 A developer pool 9 is formed in the widthwise concave portion formed. The presence of these developer pools 9 on the plate surface of the PS plate 2 eliminates the poor development at the edge of the PS plate, especially at the leading end, and also conveys the liquid in the upward direction as described above. By using a transport roller as
The generation of scratches on the back side of the PS plate is improved to a level where there is no practical problem, and the immersion of the back side of the PS plate by the developer is also improved.

It is preferable that the slit formed by the two plate members of the developing solution supply member 7 is adjusted to have a slit gap according to the amount of developing solution flowing out from the developing solution supply pipe 6.
The supply amount of the developing solution is preferably 50 to 500 m per 1 m ² of the PS plate.

As the plate material, for example, a sheet of plastic such as polyester, polyvinyl chloride, polypropylene, polyethylene, polystyrene, a sheet of metal such as stainless steel, or a sheet of rubber can be used.

The adjustment of the slit gap is performed by the developer supply pipe 13 if at least one of the two plate materials is flexible.
Since it is automatically performed according to the amount of developing solution discharged from the device, the apparatus becomes simple.

As a preferred embodiment of the above-mentioned slit, the PS plate surface has a lower end portion in which two plate materials forming the slit each have at least a flexible portion in a direction parallel to the conveying surface and in a direction orthogonal to the conveying direction. At the upper position, the plate material on the outlet side is more distal (lower end) than the plate material on the inlet side when viewed from the transport direction.
Is short (preferably 3 to 10 mm).

The angle [theta] which rises in the carrying direction and becomes a horizontal plane in the carrying direction is preferably in the range of 1 [deg.] To 45 [deg.], And particularly preferably in the range of 3 [deg.] To 10 [deg.]. The length of conveyance which rises in the conveying direction is in the range of 1 to 40 cm, preferably 3 to 10 cm, and the conveying time is 0.5 to 2
A range of 0 seconds, particularly 2 to 10 seconds is preferable.

The developing solution supply member 7 distributes the developing solution evenly across the width of the PS.
It is advantageous that it can be supplied onto the plate and can form a developer reservoir as described above. In this case, the shape is not limited to the slit shape as described above, and may be any shape such as a shape in which the plate material on the right side of the developing solution supply member 7 in FIG. 1 is removed. The developer pool is formed by providing another means, for example, a roller extending in the width direction, which prevents the developer from flowing down the surface of the developing section roller 8 or the like or the inclined surface of the PS plate 2. You may let me. Further, the developing unit roller 8 may not be a roller, and may be, for example, a semi-cylindrical plate material.

It is preferable that the PS plate 2 developed in the conveying process ascending in the conveying direction is further dipped in a developing solution. This immersion is in the development
11 and the guide roller 12 can be used. A developer having the same composition as the developer supplied from the developer supply member 7 is placed in the developer tank 11, and the replenishment by the developer brought in by the PS plate is sufficient. However, an unused developer may be replenished separately. The amount of the developing solution in the developing tank 11 is preferably 0.3 to 3 per 1 m of the conveying width, and the conveying length to be immersed in the developing solution is appropriately about 3 to 15 cm.

The PS plate 2 that has passed through the developing tank 11 is rubbed by the brush roller 13, and the developing solution is squeezed by the squeeze roller 14 to finish the development.

In such an embodiment, the time t ₁ from the time when the developer is supplied onto the plate surface of the PS plate 2 by the developer supplying member 7 until the time when the developer is immersed in the developer in the developer tank 11, the development in the developer tank 11 is performed. The time t ₂ of immersion in the liquid and the time t ₃ until the developer is removed from the developer in the developer tank 11 are preferably in the following ranges. (When the developing temperature is 25 ° C) t ₁ : 5 to 10 seconds, t ₂ : 5 to 10 seconds, t ₃ : 1 to 4 seconds
A range of 10-40 ° C is suitable.

Next, the operation of the apparatus shown in FIG. 1 will be supplemented. When the PS plate 2 is inserted from the entrance of the apparatus, the PS plate detection switch (not shown) rotates the conveying device such as the conveying roller pair 1, the brush roller 13, the squeeze roller 14 and the like to convey the PS plate. Further, the pump 5a is operated by the PS plate detection switch, and a predetermined amount of the developer is sent to the developer supply pipe 6 for a predetermined time. The developing solution flowing out from the developing solution supply pipe 6 flows down inside the two plate materials constituting the developing solution supply member 7, and becomes a continuous liquid film in the width direction at the slit portion at the lower end thereof.
It is supplied on the PS plate 2. When the PS plate 2 does not pass through the slit portion, the developer flowing out from the slit portion forms the liquid pool 9 as described above.

FIG. 2 is a side sectional view showing another embodiment of the essential part of the apparatus for carrying out the present invention.

The apparatus shown in FIG. 2 has a plurality of tilt rollers 4a and 4a instead of the tilt roller 4 and the developing unit roller 8 of FIG.
b, 4c and the curved plate 8a are used, and the immersion in the developing solution by the developing tank 11 in FIG. 1 is omitted. 1
6 is a skewer roller.

In the development processing method of the present invention, a development promoting operation can be added. For the development promoting operation, all means such as physical, chemical, electrical, mechanical, etc. for promoting the development can be used.

Further, the automatic developing machine to which the method of the present invention is applied, after the development processing step in addition to the development processing step according to the present invention, after the development processing step, the development stop processing step (the stop processing solution includes a disposable method and a circulating use method), Each individual treatment step of the desensitizing treatment step,
Development stop treatment step and subsequent desensitization treatment step, processing step combining development treatment step and desensitization treatment, or combination of development stop treatment step and desensitization treatment step, for example, JP-A-54- It may include the processing steps described in Japanese Patent Publication No. 8002.

In the PS plate used in the method of the present invention, a photosensitive layer whose solubility is changed by light irradiation is coated on a support, and a soluble layer which can be provided with an imagewise resist layer by an electrophotographic method or the like. Those provided on the support are included.

The above-mentioned photosensitive layer contains a photosensitive substance as an essential component, and as a representative example of the photosensitive substance, for example, a photosensitive diazo compound, a photosensitive azide compound, a compound having an ethylenically unsaturated double bond, Epoxy compounds that polymerize with acid catalysts, silyl ether polymers that decompose with acid, and C-
A combination of a compound having an O—C— group and a photo-acid generator may, for example, be mentioned. Examples of the photosensitive diazo compound include an o-quinonediazide compound as a positive type compound that changes into alkali solubility upon exposure to light, and an aromatic diazonium salt as a negative type compound whose solubility decreases upon exposure to light.

[Examples] Specific examples of the present invention will be described below.

Example 1 Using the apparatus of the embodiment shown in FIG. 1, as the plate material for forming the slits of the developer supply member 7, the upper (outlet side) plate material has a thickness of 75 μm, a length (width direction) of 900 mm, and a width of 900 mm. (A in Fig. 1) 175μ thickness on 50mm lower (inlet) plate
A rectangular polyethylene terephthalate sheet having m, a length of 900 mm and a width (b in FIG. 1) of 55 mm was used.

The developing unit roller 8 is made of rubber, and the developing unit roller 8 has a diameter of 80 mm and θ = 20 ° C. Development section transport length is 400mm
The developing tank 11 contains the same composition as the developing solution supplied from the developing solution supply member 7, and the developing solution supply member 7 is supplied for each plate.
The developer supplied to the PS plate from the inside flows into the tank, and the excess developer in the tank is a waste liquid.
℃, the above t ₁ , t ₂ and t ₃ are 8 seconds, 8 seconds and 4 respectively.
Seconds, 20 seconds in total.

The PS version uses SMP-N (trade name, positive PS version, Konishi Rokusha Kogyo Co., Ltd.) 1003mm x 800mm size, and the developer is SDR
-1 (manufactured by Konishi Rokusha Kogyo Co., Ltd.) was diluted 6 times and used. The developer supply rate is 160m per PS plate, and 100
The plate was processed consecutively, and the first plate and 100
As a result of offset printing of the printing plate, a good printed matter free from stains due to poor development was obtained on the leading end portion and both side portions of the PS plate.

Comparative Example 1 The same PS plate and developing solution as in Example 1 were used to perform development using the apparatus shown in FIG. The developing solution is dripped onto the PS plate from the nozzle of the developing solution supply pipe 36, and the developing liquid droplet is spread and developed on the PS plate by the diffusion plate 37 of the plastic sheet, and is conveyed on the guide plate 38 to complete the development. .

When the developing process was performed at a distance from the position below the developing droplet to the squeeze roller pair 43, that is, a developing zone of 1400 mm, a developing time of 20 seconds, and a developing solution amount of 160 m per plate, the developing solution was P.
It was spread evenly on the S plate surface, but as a result of continuously processing 100 plates, only a plate with a large amount of uneven development and unstable performance was obtained. Further, there was a residual film on the leading end and both sides of the plate, and when the obtained plate was printed under the same conditions as in Example 1, stains were generated on the residual film.

〔The invention's effect〕

According to the present invention, the uniformity of development in a development processing method of supplying a relatively small amount of developing solution to a PS plate for development using an automatic processor is improved, and in particular, insufficient development at the edges of the PS plate is improved.
Occurrence of streak-like scratches due to rubbing on the back side of the plate, and this scratch damages the surface of the lower plate when the plates are stacked after plate making, and the halftone dot reproducibility of the scratched plate decreases. The problem that occurs is solved, and the problem that the surface of the aluminum support on the back surface of the PS plate is attacked by the developer and eluted to contaminate the PS plate is also improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a developing treatment apparatus used in the method of the present invention, FIG. 2 is a side sectional view showing another embodiment of the main part of the apparatus for carrying out the present invention, and FIG. FIG. 3 is a perspective view of a development processing apparatus used for comparison. 1, 31 ... Conveying roller pair 1c ... Conveying roller, 2 ... PS plate 3 ... Pressing roller 4, 4a, 4b, 4c ... Inclination roller 5, 34 ... Developer tank 5a, 35 ... Pump 6, 36 ... Developer supply pipe 7 ... Developer supply member 8 ... Developer section roller, 8a ... curved plate 9 ... Developer reservoir, 11 ... Developer tank 12 ... Guide roller, 13 ... Brush roller 14,43 ... Squeeze roller 15 ... Waste solution tank, 16 ... Skewer roller 37 ... Diffusion plate, 38 ... Guide plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-32044 (JP, A) SAI 57-65339 (JP, U)

Claims (1)

[Claims] 1. A method of developing a photosensitive lithographic printing plate, which comprises automatically transporting the photosensitive lithographic printing plate using an automatic developing machine to develop the photosensitive lithographic printing plate, which is formed of two flexible plate materials. After supplying a substantially unused developing solution for each photosensitive lithographic printing plate to be processed from the slit of the developing solution supply member having a slit at the lower end, it is conveyed upward by the inclined roller in the conveying direction. A developing treatment method characterized in that a continuous developer pool is formed on the photosensitive lithographic printing plate in the conveyance width direction.