JP2619253B2 - Development method of photosensitive lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of developing a photosensitive lithographic printing plate (hereinafter, referred to as a PS plate). The present invention relates to an improved method for processing a PS plate in an automatic developing machine, which causes a phenomenon by supplying a used developer.

[Prior Art] When a large number of exposed PS plates are processed, an automatic developing machine is generally used.

When an exposed PS plate is processed by an automatic developing machine, the PS plate is transported horizontally and sprayed with a developer to develop it, or the PS plate is placed in a developing tank containing a large amount of developer. There is a method in which a plate is curved and immersed while being conveyed to perform a developing process. In any of these processing methods, it is necessary to prepare a large amount of developing solution for processing one PS plate. In addition, the developer is circulated and reused in order to use it economically, and during this time, in addition to the deterioration of the developer due to the processing, the phenomenon liquid deterioration due to the absorption of carbon dioxide gas from the air occurs, and the deteriorated developer is often used. It has to be replaced, and the management of the developing operation is very troublesome.

When the PS plate is processed with a large amount of a developing solution which is recycled and reused for the purpose of remedying the above drawbacks, a method of replenishing a replenisher to keep the developing process stable is known.
Nos. 55-115039 and 58-95349. Even with such a replenishment method, although the frequency of liquid replacement was reduced, liquid replacement was necessary, and the problem of replenishment accuracy and replenishment fluctuation due to varietal differences between PS plates could not be solved. Further, a replenishing device is required on top of that, and the replenishing device itself is not only expensive, but also requires adjustment and maintenance of the replenishing device.

A processing apparatus aiming at saving of a developing solution by eliminating such a troublesome replenishing method is described in JP-A-55-32044. In this system, a developer diffusion plate is provided close to the PS plate transfer path in an automatic processor to stretch the developer applied on the PS plate surface. In the processing method, the PS plate to be conveyed is not always horizontal and slightly distorted up and down, so the amount of developer tends to be uneven, development unevenness tends to occur, the PS plate to be processed and the developer diffusion plate There is a drawback that it takes time to adjust the gap between, and especially when a small amount of the developer is dropped directly on the PS plate surface, a difference in developing speed occurs between the dropping part and the non-dropping part, and the developer passes through the development diffusion plate. This difference remains afterwards, resulting in uneven development, which may result in an undesirable printing plate.

We have developed a method and an apparatus for developing a PS plate capable of stabilizing the development process by using a small amount of a developing solution by improving such a disadvantage, and have already filed an application as Japanese Patent Application No. 61-82900.

However, we have found that such a developing method has the following problems. That is, in the circulation development (a method of circulating and using the developer), a relatively large amount of the developer is supplied to the PS plate, and a shower or the like is applied to a brush to prevent drying and enhance a development promoting effect. But,
In the developing method of disposing of a new solution, it is difficult to apply a shower to a rubbing member such as a brush or a sponge because the amount of the solution is small. Therefore, we have found that the rubbing member dries, thereby causing the plate to be soiled.

[Problems to be solved by the invention]

Therefore, an object of the present invention is to prevent a rubbing member such as a brush or a sponge from drying in a PS plate developing method in which a relatively small amount of a developing solution is supplied to a PS plate to develop the plate, and a plate that is always free of stains. An object of the present invention is to provide a developing method which can be obtained.

Another object of the present invention is to provide a developing method in which a relatively small amount of a developing solution is supplied to a PS plate to perform development, in which a development promoting effect is enhanced and a plate free of stains is always obtained. It is.

[Means for solving the problem]

The above problem is that the photosensitive lithographic printing plate is automatically conveyed using an automatic developing machine, a substantially unused developing solution is supplied onto the drying lithographic printing plate, and a development promoting operation is provided. In the method of developing, a developing method of a photosensitive lithographic printing plate is characterized in that the developing process is performed such that a pair of rollers of a development accelerating member provided outside a developing tank is immersed in a developer pool. I found it solved.

In the present invention, there is no particular limitation on a means for supplying a substantially unused developer onto the PS plate, but from the viewpoint that uniform development results can be obtained with a relatively small amount of developer, the widthwise direction (PS plate) (Horizontal direction perpendicular to the conveying direction of the PS plate), it is preferable that the developing solution is supplied at the same time as possible, and that a developing solution film having a uniform thickness is formed on the PS plate surface.

The development promoting operation in the present invention is performed by holding the developer film on the PS plate with a development promoting member such as a brush or a sponge.
Rub the plate surface to accelerate development. This development promoting member is
The PS plate is rubbed while applying a certain amount of pressure.
The PS plate surface is rubbed while transporting the plate.

At this time, in the method of supplying a relatively small amount of developer,
The problem that these rubbing members are easily dried and the development promoting effect is reduced when the rubbing members are dried, and the problem that the processed plate is easily stained is solved by immersing the lower portion of the pair of rollers in the developing solution. .

In the present invention, it is preferable to use a brush roller (rotating brush roller) that is driven and rotated as a development promoting member. Further, the pair of rollers is preferably a roller having a roughened peripheral surface.

As the developer for dipping the pair of rolls of the development accelerating member, the same type as the developer supplied on the PS plate can be used. The replenishment is sufficient because the developer supplied on the PS plate flows down from the PS plate surface in the vicinity of the development accelerating member.

When the developer on the PS plate surface is squeezed with a squeeze roller at the final stage of the development process according to the present invention, it is preferable that the lower part of the roller below the squeeze roller is immersed in the developer. In such an embodiment, the same developer as the developer supplied on the PS plate can be used. When the squeeze roller and the paired roller of the development promoting member are adjacent to each other, both can be immersed in one developer tank.

 Next, the present invention will be described 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, a pair of transport rollers 1a and 1b nip and transport the PS plate 2, and a pressing roller 3 is for maintaining the transport position of the PS plate 2 properly. Reference numeral 4 denotes an inclined roller, and the inclined roller 4 is provided by a roughened guide member so that the PS plate 2 to which the developer is supplied is conveyed in a direction of ascending in the conveying direction. The developing solution in the developing solution tank 5 is sent to a developing solution supply pipe 6 by a pump 5a. The developer supply member 7 has a slit formed by a secondary plate at its lower end, and the developer flowing down from the developer supply pipe 6 is supplied to the PS plate 2 through this slit. 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 in contact with the developing roller 8.
When the PS plate 2 being conveyed is in this position, a concave portion in the horizontal direction (hereinafter, referred to as “width direction”) orthogonal to the conveying direction formed by the lower end of the developing unit roller 8 and the developer supply member A developer pool 9 is formed in a widthwise recess formed at a contact portion between the lower end of the PS plate 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 unit roller except for the front and rear ends thereof.

First, the leading end of the PS plate 2 to be transported enters the liquid reservoir 9 in the concave portion formed by the developer supply member 7 and the developing roller 8. After the leading end of the PS plate 2 has passed through the developer pool 9 formed in the widthwise recess formed by the developer supply member 7 and the developing roller 8, the PS plate 2 and the developer supply member 7 A developer pool 9 is formed in the formed widthwise concave portion. When these developer pools 9 are present on the plate surface of the PS plate 2, the liquid film thickness on the PS plate to be conveyed becomes uniform, which is effective for eliminating uneven development, but is insufficient.
The edge portion is subjected to additional development by a later-described developing tank 11. As means for transporting the PS plate 2 in the ascending direction in the transport direction, means for sliding on an inclined guide plate, a flat roller-shaped transport roller, or the like can be used.

The slit formed by the two plate members of the developer supply member 7 is preferably configured to be adjusted to a slit gap corresponding to the amount of the developer flowing out from the developer supply pipe 6. PS plate 1m ² per 70~700ml is preferable.

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

The adjustment of the slit gap may be performed if at least one of the two plate members is flexible.
This is automatically performed in accordance with the amount of the developing solution discharged from the apparatus, so that the apparatus is simplified.

According to a preferred embodiment of the slit, the lower end thereof has a portion in which two plate members forming the slit have at least flexibility in a direction parallel to the transport surface and in a direction orthogonal to the transport direction, respectively. At the position on the plate surface, there is a mode in which the tip (lower end) of the plate on the exit side is shorter (preferably 3 to 10 mm) than the plate on the entrance side when viewed from the transport direction.

The angle θ that forms a horizontal plane in the transport direction that rises in the transport direction is preferably in the range of 1 ° to 45 °, and particularly preferably in the range of 3 ° to 10 °. The transport length ascending in the transport direction is preferably in the range of 1 to 40 cm, particularly 3 to 10 cm, and the transport time is 0.5
The range is preferably from 20 to 20 seconds, particularly from 2 to 10 seconds.

The developer supply member 7 supplies the developer uniformly in the width direction.
Advantageously, it can be supplied on a PS plate and can form a developer pool as described above. The developing solution pool is provided with another means, for example, a roller extending in the width direction, and is conveyed with the surface of the developing unit roller 8 or the like or inclined.
The developer may be formed by blocking the developer flowing down the surface of the PS plate 2. Further, the developing unit roller 8 may not be a roller,
For example, a semi-cylindrical plate may be used.

The PS plate 2 developed in the transport process ascending in the transport direction is further immersed in a developer. This immersion can be performed by the developing tank 11 and the guide roller 12. The developing solution tank 11 contains a developing solution having the same composition as the developing solution supplied from the developing solution supply member 7, and the replenishment is sufficiently performed by the developing solution carried by the PS plate. However, an unused developer may be replenished separately. The developer volume in the developing tank 11 is 1m
It is preferably 0.3 to 3 per unit, and the conveyance length for immersion in the developer is suitably about 1 to 15 cm.

The PS plate 2 that has passed through the developing tank 11 is rubbed by a brush roller 13 which is a development accelerating member, and then the developer is squeezed by a squeeze roller 14 to complete the development.

Reference numeral 13a denotes a pair of rollers, the lower part of which is immersed in the developer put in the developer tank 15 together with the lower one of the two rollers constituting the squeeze roller 14. The pair of rollers preferably has a roughened peripheral surface.

2 to 6 show examples of the shape of the rough surface of the pair of rollers 13a. FIG. 2A is a schematic front view, and FIG. 2B is a partially enlarged view or a partially enlarged perspective view thereof.

FIG. 2 shows the oblique streaks continuous shape, FIG. 3 shows the oblique streaks cross continuous shape, FIG. 4 shows the horizontal streak independent shapes, FIG. 5 shows the vertical and horizontal streak cross shapes, and FIG. This shows the shape of the rough surface. Preferred is a continuous oblique line as shown in FIG.

Table 1 below shows examples of preferred dimension ranges in the rough surface shapes shown in FIGS. 2 to 6. The diameter of the roller pair is 10
A range of 100100 mm is preferred.

The material constituting the surface of the pair of rollers 15 is metal (for example, stainless steel, copper, etc.), plastic (for example, phenol resin, urea resin, melamine resin, polyester resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, etc.). ), Rubber, wood, glass, ceramics and the like that are not easily affected by the developer.

The substantially unused developer in the method of the present invention is:
It means a developer having the same developing capacity as an unused developer.In addition to a completely unused developer, a used developer is mixed with an unused developer within a range that does not reduce the developing capacity. May be used.

In the above embodiment, the time t ₁ from when the developer is supplied from the developer supply member 7 to the plate surface of the PS plate 2 until the developer is immersed in the developer in the developer tank 11, It is preferable that the immersion time t ₂ and the time t ₃ until the developer is removed from the developer in the developer tank 11 to be removed are within the following ranges. (For developing temperature 25 ℃) t _1: 2~20 seconds, t _2: 2 to 20 seconds, t _3: 1 to 10 seconds developing temperature 10
A range of 40 ° C is appropriate.

Next, the operation of the apparatus shown in FIG. 1 will be supplemented. PS
By the start of plate development processing, the developing tank 11 and the developing tank 15
Is filled with a PS plate developer to be processed. When the PS plate 2 is inserted from the entrance of the apparatus, a transfer device such as a pair of transfer rollers 1 and a brush roller are operated by a PS plate detection switch (not shown).
13, the roller 13a, the squeeze roller 14 and the like rotate to convey the PS plate. Further, the pump 5a is operated by the PS plate detection switch, and sends a predetermined amount of the developing solution to the developing solution supply pipe 6 for a predetermined time. The developing solution flowing out of the developing solution supply pipe 6 flows down inside the two plates constituting the developing solution supply member 7,
A liquid film continuous in the width direction is formed on the plate surface of the PS plate 2 at the slit portion at the lower end thereof. When the PS plate 2 does not pass through the slit, the developer flowing out of the slit forms a liquid pool 9 as described above.

In the development processing method of the present invention, a development acceleration operation other than those described above can be added. In the development accelerating operation, any means such as physical, chemical, electrical and mechanical for accelerating the development can be used.

In addition, the automatic developing machine to which the method of the present invention is applied may include, in addition to the developing step according to the present invention, if necessary, after the developing step, a developing stop processing step (a stop processing liquid includes a disposable method or a circulating method) Each of the desensitization processing steps, a development stop processing step followed by a desensitization processing step, a processing step combining a development processing step and a desensitization processing, or a development stop processing step and a desensitization treatment It may include, for example, a processing step described in JP-A-54-8002 in combination with a processing step.

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

The photosensitive layer contains a photosensitive substance as an essential component, and typical examples of the photosensitive substance include, 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 and C that decompose with acids
Examples include a combination of a compound having a -OC- group and a photoacid generator. Examples of the photosensitive diazo compound include an o-quinonediazide compound as a positive type compound which changes to alkali-soluble upon exposure, and an aromatic diazonium salt as a negative type compound whose solubility decreases upon exposure.

The negative PS plate developer used in the method of the present invention includes, for example, anions as described in JP-A-51-77401, JP-A-51-80228, JP-A-53-44202 and JP-A-55-52054. Surfactant, water solubility 10% by weight at room temperature
An aqueous solution comprising the following organic solvent, alkali agent, water and, if necessary, an antifouling agent is included.

The developer for the positive working PS plate used in the method of the present invention includes an alkali metal hydroxide, an alkali metal silicate, an alkali metal phosphate or an alkali metal aluminate, water and, if necessary, a surfactant or other surfactant. A strong alkaline aqueous solution having a pH of 12 or more comprising an additive is included. Specifically, JP-A-48-1553
No. 5, No. 53-82324, No. 54-62004, No. 52-127338,
Nos. 53-96307, 50-144502, 55-22759, 55
-25100, 55-95946, 55-115039, 56-14
Examples of the developer include sodium silicate and potassium silicate described in JP-A Nos. 2528 and 50-51324.

Further, a developer for dual use of a negative PS plate and a positive PS plate as described in JP-A-60-13074 can be used.

〔Example〕

 Hereinafter, specific examples of the present invention will be described.

Example Using the apparatus of the embodiment shown in FIG. 1, as a plate material for forming a slit, the upper (outlet side) plate material was 75 μm in thickness, 900 mm in length (in the direction perpendicular to the conveyance direction), and width (FIG. 2). A) 50mm, 175μ thickness on the lower (entrance side) plate
A rectangular polyethylene terephthalate sheet having a length of 900 mm, a length of 900 mm and a width (b in FIG. 2) of 55 mm was used.

The developing roller 8 is made of rubber, β = 20 °, and the diameter of the roller 8 is 80 mm. The inclined roller 4 is of a type made of rubber and using an O-ring. The flat roller diameter of this roller is 20
mm. The transport length of the entire developing section is set to 400 mm, and the developing tank 11 is filled with the same composition as the developing solution supplied from the developing solution supply member 7, and the developing solution supplied to the PS plate from the developing solution supply member 7 for each plate. Flowed into the tank, and the excess developer became a waste liquid in the tank. Outer diameter 80mm as development promoting member,
Hair length 20mm, hair material is nylon brush roller PS
It was driven at a peripheral speed of 2 m / min relative to the plate.

As the roller pair, a roller having an outer diameter of 40 mm and a peripheral surface made of neoprene rubber and having irregularities on the peripheral surface as shown in FIG. 2 (interval between concave portions 1 mm, depth of concave portions 0.5 mm) was used. The developer tank 15 used had a capacity of 3, and the roller below the squeeze roller was also immersed as shown in FIG. Developer temperature 25
° C, said t ₁ , t ₂ and t ₃ are 8 seconds, 8 seconds and 4
Seconds, for a total of 20 seconds.

The PS plate used was 1003 mm × 800 mm size of SMP-N (trade name, positive PS plate, manufactured by Konishi Roku Kogyo Co., Ltd.), and the developer used had the following composition.

(Developer) Sodium silicate (JIS standard No. 3) 20 g Sodium hydroxide 5 g Perex NBL (manufactured by Kao Atlas Co., Ltd.) 0.5 g Water 975 g As a result, the PS
There is no stain on the plate surface, and among the obtained plates, as a result of offset printing of the 1st and 100th plates, good printed matter without stains due to poor development at the leading edge and both sides of the PS plate Obtained.

Comparative Example The same experiment as in the above example was performed except that the developer tank 15 was removed. As a result, the PS plate surface was stained on 5 out of 100 plates due to drying of the brush roller.

〔The invention's effect〕

According to the present invention, a PS plate is developed with a relatively small amount of a developer,
The development of a PS plate surface due to drying of a development promoting member such as a brush roller or a sponge roller used in the development promoting operation in a developing method in which a development promoting operation is imparted and developed is improved. The properties are also improved. Therefore, according to the present invention, there is provided a method for developing a PS plate having excellent development uniformity and stability.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a developing device showing one embodiment of the present invention. FIGS. 2 to 6 are a schematic front view (a) showing an example in which the peripheral surface of the pair of rollers used in the present invention is roughened, and a partially enlarged view or a partial perspective view (b) thereof. DESCRIPTION OF SYMBOLS 1 ... Conveyor roller pair 2, PS plate 3 ... Holding roller 4 ... Inclination roller 5 ... Developer tank, 5a ... Developer supply pump 6 ... Developer supply pipe 7 ... Developer supply member , 8 Developing roller 9 Developing liquid reservoir 11 Developing tank 12 Guide roller 13 Brush roller 13 a Pair roller 14 Squeeze roller 15 Developing liquid tank 16 ... Waste liquid tank 20 ... Washing section

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-42202 (JP, A) Jpn. Microfilm (JP, U)

Claims (1)

(57) [Claims] 1. A photosensitive lithographic printing plate is automatically conveyed by using an automatic developing machine, a substantially unused developing solution is supplied onto the photosensitive lithographic printing plate, and a development promoting operation is applied. A method for developing a photosensitive lithographic printing plate, wherein the developing process is performed such that a pair of rollers of a development accelerating member provided outside a developing tank is immersed in a developer pool.