JPS63194267A - Method for processing photosensitive planographic printing plate by which stability and the like of developing process are improved - Google Patents

Abstract

PURPOSE:To eliminate the need for exchanging a developing soln. and to improve workability by supplying the substantially unused developing soln. to the surfaces of PS plates to be used for each one sheet thereof and developing the plates, then supplying an aq. soln. or nonsensitizing liquid contg. a substantially unused surfactant to the surfaces of the printing plates and processing the plates. CONSTITUTION:Pumps 12, 12' operate to supply the diluted developing soln. onto the exposed photosensitive planographic printing plate (PS plate) from a processing liquid supplying nozzle 7 at the time of subjecting the PS plate to the developing process with an automatic developing machine. The unused rinsing liquid or nonsensitizing liquid prepd. by mixing the rinsing liquid or nonsensitizing liquid in a rinsing liquid and nonsensitizing liquid tank 22 and the water for dilution in a dilution water tank 22' fed respectively by pumps 23, 23' is then supplied from a processing liquid supplying nozzle 7'' to the PS plate which is discharged by passing a rinsing process section 2. The high-quality PS plate is thus obtd. by using a relatively small volume of the developing soln. The always stable processing after the development is permitted even when many sheets of the plates are processed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for processing photosensitive lithographic printing plates, and more specifically, to a photosensitive lithographic printing method that has been improved so that stable development processing can be carried out at all times. Change the plate development method.

[Conventional technology]

Exposed photosensitive lithographic printing plate (hereinafter simply referred to as PS plate)
When processing a large number of sheets, it is common to use an automatic developing machine, and the developer used at the same time is an alkaline developer that uses water as the main solvent due to odor and environmental protection issues. .

When processing an exposed PS plate in an automatic developing machine, a method is used in which the plate is conveyed horizontally and immersed in a developer while being sprayed. In all of these processing machines, it is necessary to prepare a large amount of developer to process one PS plate. In addition, in order to use the developer economically, the developer is recycled and reused. During this process, the developer deteriorates due to the absorption of carbon dioxide gas from the air, in addition to the deterioration of the developer due to processing. had to be replaced, making it extremely troublesome to manage the developing process.

In addition, in order to improve the above-mentioned drawbacks, there is a known method to keep the development process stable by replenishing a replenisher when a PS plate is processed with a large amount of circulating and reused developer.
-144502, 55-115039, 58-
No. 95349 and other public laws. However, even with this replenishment method, although the frequency of liquid exchange is reduced, it is still necessary to exchange the liquid, and the problem of replenishment accuracy and fluctuations in replenishment due to product differences between PS plates cannot be solved. In addition, a replenishment device is required, and not only is the replenishment device itself expensive, but the replenishment device also requires adjustment and maintenance.

Further, a method for eliminating the troublesome replenishment method and saving developer is described in Japanese Patent Laid-Open No. 55-32044. This relates to a photographic processing device equipped with a developer diffusion plate close to the photosensitive material transfer path in an automatic processor, and a method for processing PS plates with a small amount of developer using this device. However, it has the disadvantage that it is difficult to shorten the development time and cannot perform rapid processing.Also, since the PS plate being transported is not necessarily horizontal but is slightly distorted up and down, the amount of developer tends to be uneven, making it difficult to develop. There are disadvantages in that unevenness tends to occur and it takes time and effort to adjust the gap between the lithographic printing plate being processed and the developer diffusion plate.

[Problem that the invention seeks to solve]

On the other hand, there were some problems in post-processing after development. Generally, when producing a lithographic printing plate by processing an image-exposed PS plate using an automatic developing machine, conventionally, in the washing process after the development process, a large amount of water is used for washing, and the The washing water was directly discharged. However, for reasons such as pollution control and securing water resources, it is not preferable to use a large amount of washing water, and should be avoided as much as possible.

Therefore, a treatment method that eliminates the need for washing with water was proposed in Japanese Patent Application Laid-Open No. 54-8002.
No. 55-12921, No. 55-115045, etc. However, in these methods, the PS plate is immediately treated with a desensitizing solution or an aqueous solution containing a surfactant (hereinafter referred to as rinsing solution) after passing through the development tank. The remaining developing solution that has not been squeegeeed onto the lithographic printing plate will be carried over. When processing a large number of PS versions,
The developing solution carried in in this way is accumulated, and as a result, a considerable amount of the developing solution is carried into the rinsing solution or the desensitizing solution. The development processing solution brought in contains not only the development processing solution but also resin components eluted during the development processing. This developing treatment solution and resin content reduce the performance or processing ability of the rinsing solution or desensitization treatment solution, resulting in serious problems such as scumming and poor inking of the lithographic printing plate.

On the other hand, in place of the above-mentioned treatment method that eliminates washing with water for reasons such as anti-pollution measures and securing water resources, a method of using circulating washing water is proposed in JP-A-57-158643 and JP-A-59.
-58431, No. 59-57242, etc. By using this circulating water washing method, the amount of developing solution and resin carried into the rinsing solution or desensitizing solution can be considerably reduced, and as a result, the deterioration of the processing capacity of the rinsing solution or desensitizing solution can be suppressed to some extent. Although it can be done, it is not sufficient and the liquid still needs to be replaced.

Accordingly, a first object of the present invention is to provide a PS plate processing method that solves the problems of the conventional techniques as described above and allows stable development processing to be obtained at all times. Also, the second
The purpose of the present invention is to provide a PS plate processing method that eliminates the need for developer management and solution replacement and has improved workability. The third purpose is to create an inexpensive PS that does not require a replenisher or developer replenisher.
An object of the present invention is to provide a method for developing a plate. A fourth object is to provide a processing method that allows stable post-development processing even when a large number of PS plates are processed.

[Means for solving problems]

The above object of the present invention is to process exposed P using an automatic processor.
In the method of automatically conveying and developing S plates, substantially unused developer is added to the P plate for each of the 28 plates processed.
After being supplied to the printing plate surface of the S plate and developed, a water washing step or no water washing treatment is performed, and then an aqueous solution containing a substantially unused surfactant or a fat-proofing liquid is supplied to the printing plate surface for treatment. This is achieved by a processing method characterized by:

The term "substantially unused developer" as used herein means a developer that has the same developing ability as an unused developer, and includes a developer that is completely unused, as well as a developer that has the same developing ability as an unused developer. It is also possible to mix and use a used developer within a range that does not reduce the quality of the plate.For example, during development, the used developer can be supplied from a part of the developer supply means to the plate surface along with the unused developer. It is also possible to use methods such as supplying and developing.
It is most preferable to use all virgin liquid.

Methods of supplying the developer onto the PS plate include, for example, using a shower pipe or nozzle to inject, spray, or drop the developer onto the plate surface, or placing the developer in a position that is in contact with or not in contact with the plate surface. There is a method in which the developer is supplied from a co-feeding member in such a way that it is applied to the plate surface.

Methods of bringing the developer supplying member into contact with the PS plate and supplying the developer onto the plate include, for example, a method of supplying the developer by rubbing the surface with a water-absorbing member such as a sponge or cloth, or a method of supplying the developer by rubbing the surface with a water-absorbing member such as a sponge or cloth, or a method using a material such as rubber. Regardless of whether it is a non-water-absorbing member or a water-absorbing member such as the sponge or cloth mentioned above, methods include forming these members into a roller shape and feeding the PS plate while synchronizing the rotation of the roller with the transported PS plate. .

In addition, the developer can be supplied without contact between the developer supply member and the PS plate.
For example, there is a method of supplying the developer onto the plate by storing the developer in a narrow gap and passing the PS plate through it, or a method of supplying the developer by allowing the developer to hang down in the form of drops due to surface tension on the developer supply member. Supply by bringing the PS plate into contact with the solution, or by storing the developer in a cylindrical object, creating a narrow gap on the side of the cylindrical object, and passing the PS plate through the gap. Examples include methods. Furthermore, in these developer supply methods, the developer can be supplied onto the PS plate not only in liquid form but also in foam form.

Other methods of supplying a developer include attaching the developer to a film base and laminating it on a PS plate, or supplying a waxy developer to a PS plate.
Examples include a method of supplying the material by bringing it into contact with the plate.

Further, as the developer supply method, only one method may be used, or two or more methods may be used in combination.

l of the developer supplied by these methods is 25 plates 1
It can be determined based on various criteria, such as a fixed amount per sheet, an amount proportional to the area of the PS plate, or an amount proportional to the length or width of the PS plate to be processed. This can also be changed depending on the area of the non-image portion of the image to be formed. It may be selected as appropriate depending on the structure of the zero-motion developing machine, the size and seed head of the PS plate to be processed, the printing plate, the properties of the developer, etc., but it is desirable that the number is 11 or less per plate.

In addition, the temperature of the developer during use is usually 5°C to 60°C,
Preferably 10°C to 45°C, more preferably 25°C
The temperature ranges from 35°C to 35°C.

The developing solution can be stored in a storage tank after being finished as a working solution and supplied onto the PS plate during processing, or it can be divided into an undiluted solution, a diluted solution, or multiple solutions with different compositions. It is possible to store the liquid in a storage tank and supply each liquid onto the printing plate, or to mix it automatically at the time of supply to finish the liquid for use, but it is better to mix it automatically and supply it to the printing plate in a uniform state. is preferred.

In the method of the present invention, substantially unused developer is supplied for every 28 plates inserted into the automatic processor. Therefore, the processing device is provided with a means for detecting the presence of the PS plate, and the PS plate is detected by the signal supplied from the developer tank onto the plate surface while the PS plate is being conveyed through the developing section. As the means, various known non-contact or contact sensors such as optical sensors and microswitches can be used.

Further, the developer supply section has a control mechanism that is linked to a detection mechanism such as a sensor that detects the presence or absence of a PS plate.
Before the plate is carried into the developing section and after passing through, the stop mechanism (
It is desirable that the

In the present invention, a development accelerating operation can be applied. Development acceleration operations include physical, chemical,
All means, electrical and mechanical, can be used.

Mechanical acceleration means include a method of rubbing the plate surface, for example, a method of rubbing with a rotating roller-like rubbing member, a method of rubbing by rotating a flat-shaped rubbing member, a method of rubbing the plate-like rubbing member back and forth and/or left and right. Examples include a method of rubbing by moving a roller-shaped rubbing member or a flat-plate rubbing member while rotating it and moving it back and forth and/or left and right. Note that these rubbing members may be used in combination.
These rubbing members can be created using, for example, brushes, sponges, cloth, or the like.

Other development accelerating means include, for example, a method of blowing high-pressure air, a method of irradiating ultrasonic waves, a method of applying vibration to a printing plate, and an electrochemical method as described in JP-A-58-42042. A method of developing the PS plate, a method of instantly heating the developer on the PS plate by microwave irradiation,
Alternatively, a method may be used in which the plate surface is polled using a processing liquid containing an abrasive powder.

The timing to add the development acceleration operation is before supplying the developer.
Alternatively, it may be added at any time during or after supplying the developer, but it is preferable to add it during or after supplying the developer.

Further, the developer supplying means and the development promoting means may be integrated. For example, when the development promoting means is a disc-shaped brush and the developer supplying means is a nozzle, a circular brush may be used. It is also possible to install the nozzle at the center of the rotation axis.

In the present invention, the time for the 18th plate to pass through the development zone is preferably 5 seconds to 60 seconds.
The 8th version is sent to the subsequent processing section.

In the present invention, as a step following development, a water washing treatment may be performed, or a treatment with an aqueous solution containing a surfactant (hereinafter simply referred to as a rinsing liquid) or a nonfatting liquid may be performed without a water washing process. .

The washing process after development includes a method of processing with circulating washing water (hereinafter referred to as circulating washing), and a method of processing with circulating washing water, 28 plates to be processed 1
A preferred washing method is disposable washing using a small amount of washing water of 11 or less per plate. Further, a water washing promotion operation can be added to the water washing step. All physical, chemical, electrical, mechanical, etc. means for promoting water washing can be used for the water washing promotion operation. In the present invention, the 18th plate after development is processed in the water washing processing section. The time is preferably 5 seconds to 60 seconds.

In the present invention, the developer on the surface of the PS plate after development does not need to be squeegeeed, but it is more preferable to squeegee. This is because contamination by the aqueous surfactant solution and the desensitizing agent developer is prevented as much as possible, and the processing capacity of the aqueous surfactant solution and the desensitizing agent is increased. Therefore, the amount of developer remaining on the PS plate after squeegeeing is preferably 12 m//m2 or less, more preferably 9I11/plow2 or less. ! & is also preferably 5 mlb' or less.

In the present invention, substantially unused rinsing liquid or desensitizing liquid is applied to the surface of the 18th plate that has been washed with water, depending on the type of the 18th plate (particularly the negative type 28th plate and the positive type 25th plate). supply and process without changing.

Methods for supplying and processing these processing liquids onto the plate surface of the 18th plate include the method using the developer described above, a method in which the processing liquid is jetted from a nozzle onto the plate surface of the 18th plate, and a method in which the processing liquid is jetted from a nozzle onto the roller surface. Any method can be used, such as applying the processing liquid to the plate surface of the 18th plate through a roller, but by using the necessary amount of these processing liquids each time, the PS plate unit to be developed can be It becomes possible to greatly reduce the amount of rinsing liquid or desensitizing liquid used per cleaning.

In the present invention, the rinsing liquid and the desensitizing liquid can be used not only as unused liquids, but also as a mixture of used processing liquids within the range that does not reduce the processing capacity of the unused liquids. Most preferably, fresh liquid is used.

In the method of supplying substantially unused rinsing liquid or desensitizing liquid to the lithographic printing plate in small amounts at each processing time, these processing liquids are uniformly supplied onto the PS plate. Therefore, the number of rinsing liquid or desensitizing liquid plates to be used is preferably 11 or less per plate, and more preferably 300 ml or less. Furthermore, the number of rinsing treatment tanks or desensitization treatment tanks may be single or plural, and in the case of two or more, the treatment liquids in each tank may be different.

It is desirable that a lithographic printing plate treated with a rinsing liquid or a desensitizing liquid be smeared so that the amount and thickness of the coating film of the rinsing liquid or desensitizing liquid are as uniform as possible and in an appropriate amount. , the desirable coating amount is 1 ml/m2 or more, 2
It is 0 m1/l112 or less. A more preferable coating amount is 10+*j on the plate surface! /m' or less.

The 28th plate targeted by the present invention is one in which a photosensitive layer whose solubility changes upon irradiation with light is coated on a support, or a soluble layer in which an image-like resist layer is formed by an electrophotographic method or the like. is provided on a support.

Various types of supports can be used for the 28th edition, including paper, plastics, metals, and laminated paper. Among these, aluminum and aluminum-coated composite supports are particularly preferred.

Further, the surface of the aluminum material is preferably roughened to increase water retention and improve adhesion to the photosensitive layer.

There are various methods for surface roughening treatment, but a method including the use of electrolytic etching is preferred.

Further, the roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary.

The aluminum plate thus obtained is desirably subjected to anodizing treatment, and particularly preferably, a method of treatment with a solution containing sulfuric acid or phosphoric acid is given.

Furthermore, if necessary, a sealing treatment and other surface treatments such as immersion in a potassium fluorozirconate aqueous solution can be performed.

The 28th edition photosensitive composition used in the present invention contains a photosensitive substance as an essential component, and the physical and chemical properties of the photosensitive substance do not change upon exposure or subsequent development treatment. For example, there are differences in solubility in developing solutions due to exposure, differences in intermolecular adhesive strength before and after exposure, differences in affinity for water and oil due to exposure or subsequent development, and A material that can form an image area by electrophotography can be used.

Typical photosensitive substances include, for example, photosensitive diazo compounds, photosensitive azide compounds, compounds with ethylenically unsaturated double bonds, epoxy compounds that polymerize with acid catalysts, silyl ether polymers that decompose with acids, and C-0-
Examples include a combination of a compound having a C-group and a photoacid generator.

Examples of photosensitive diazo compounds include 0-quinonediazide compounds as positive types that change to alkali solubility upon exposure, and aromatic diazonium salts as negative types that decrease solubility upon exposure.

The developer used in the present invention is preferably an aqueous alkaline developer.

Further, the developer may contain an organic solvent, a surfactant, a neutral salt, a chelating agent, and various other additives.

The printing plate obtained by development is treated immediately or after washing with water (including circulating water washing), with a desensitizing solution if erasing is not required, or with a rinsing solution if erasing is required.

The desensitizing liquid that can be used in the present invention contains a water-soluble polymer compound and water as essential components, and optionally contains surfactants, acids, water-soluble salts, lipophilic substances, wetting agents, organic solvents, and preservatives. It can contain a fine agent and the like.

Many specific examples of these anti-greasy agents are listed in Japanese Patent Application No. 176524/1988, P19 to P38 of the specification 4 of the present applicant, among which gum arabic is preferred because it has high anti-grease properties in non-image areas. In addition, products that use gum arabic and one or more other water-soluble polymer compounds in combination,
It is preferable because it can increase the hydrophilic fat desensitization of the non-image area without reducing the oil sensitivity of the image area, and among them, a combination of gum arabic and dextrin is most preferably used.

The anti-greasing agent is considered to have the effect of removing the alkaline developer adhering to the developed 28 plate and changing the non-image areas of the plate to have a property that is more compatible with water.

In addition, as a rinsing liquid, Japanese Patent Application No. 1986-1 filed by the present applicant
75400 Specification PL7 to P25 as examples,
The most preferred examples are alkylbenzene sulfonic acid salts and dialkyl sulfosuccinate ester salts, which have strong dispersing power.

It is preferable that these rinsing liquids further contain either or both of an acid and a water-soluble salt as a fI street agent, and further contain a preservative, a fungicide, and an antioxidant; Can be done.

It is also preferable to contain a lipophilic container.

The lithographic printing plate treated in this way is preferably dried to prevent dust from adhering to it or to make it easier to handle.The preferred drying temperature is 20°C.
~120°C.

The lithographic printing plate obtained by the treatment can be subjected to steps such as development ink application, addition, erasure-washing, erasure-washing-non-greasing treatment, etc., as necessary before printing.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Example] First, the following PS plates (A) and [B] were prepared and exposed. In addition, the percentages in the following text are weight percentages.

Parts indicate parts by weight.

(PS version [A]) Two JIS1050 aluminum plates with a thickness of 0.24 mm
% sodium hydroxide aqueous solution, degreased, electrochemically surface-treated in a dilute nitric acid solution, thoroughly washed, and anodized in a dilute nitric acid solution. An oxide film of .5 g/m2 was formed on the surface of the aluminum plate. After washing the obtained aluminum plate with water and drying, a photosensitive solution having the following composition was applied to give a dry type Ji of 2.5 g/m2, and the size of the 0 plate, which was dried to obtain a positive type 25 plate [A], was 1001003800 mm. And so.

(Photosensitive liquid) Naphthoquinone-1,2-diazide (2)-5-sulfonic acid ester of pyrogallol-acetone resin (synthesized by the method described in Example 1 of Japanese Patent Publication No. 43-28403) -1-- ~1 part cresol-xylenol-formaldehyde resin ---3 parts tert
-Butylphenol-formaldehyde resin---0, 1 part Oil Blue #603 (manufactured by Orient Chemical Co., Ltd., dye)------
-0.03 parts Crystal violet (manufactured by B, A, S, F, dye) ・----0
, 03 parts ethylene glycol monoethyl ether ---
--20 copies This PS plate [A] was adhered to a transparent positive film and exposed for 60 seconds from a distance of 700 mm using a 2 kilowatt metal halide lamp.

(PS version [B]) Two JIS1050 aluminum plates with a thickness of 0-24 mm
The surface was degreased by immersion in a 0% sodium phosphate aqueous solution, electrochemically roughened in a dilute nitric acid solution, thoroughly washed, and then anodized in a dilute sulfuric acid solution to achieve 1.5+r/wheel 2 oxidation. A film was formed on the surface of the aluminum plate.

The obtained aluminum plate was further immersed in an aqueous solution of sodium metasilicate for pore sealing, washed with water, and dried. Then, the following photosensitive solution was applied to give a dry Ji of 2°0 g/112, and then dried. The size of the negative version 28 ([3)] was the same as that of the PS version (A).

(Photosensitive liquid) Hexafluorophosphate of a condensate of p-diazodiphenylamine and paraformaldehyde ------1 part 2-hydroxyethyl methacrylate-I copolymer (U.S. Pat. No. 1,
No. 505,739, Example 1) -
----10 parts Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd., dye) ----0,2 parts ethylene glycol monomethyl ether----io
Part o A transparent negative film was brought into close contact with this PS plate [B] and exposed for 30 seconds from a distance of 70 cm using a 2 kW metal halide lamp.

Example 1 The above-exposed PS plates CA) and [B] were developed at 25° C. for 40 seconds using an automatic developing machine as shown in FIG. FIG. 1 is a schematic side sectional view showing the development processing apparatus used in this example. The entire processing apparatus consists of a development processing section 1, a washing processing section 2, and a rinsing liquid/desensitizing liquid processing section 3.

The development processing section 1 mainly includes a development processing tank 4. Transport roller pair 5, rotating brush 6, processing liquid supply nozzle 7, squeezing roller pair 8, guide plate 9, developer storage tank 11, dilution water tank 11', developer supply pump 12, dilution water supply pump 12' It consists of a pump 12.12' during development.
is operated to supply the diluted developer from the processing liquid supply nozzle 7 onto the plate 23.

The developer used in the development process is squeezed by a pair of squeezing rollers 8 and stored in a waste liquid tank 13. The developed PS plate is then processed in the washing section 2 with circulating washing water.

The rinsing liquid/desensitizing liquid processing section 3 is a zone where processing is performed using a rinsing liquid or a desensitizing liquid, and mainly uses the rinsing liquid/desensitizing liquid.
It consists of a desensitizing liquid treatment tank 20, a pair of transport rollers 5'', a treatment liquid supply nozzle 7'', a pair of squeezing rollers 8', a roller 10, and a movable brush 21. The rinsing liquid (undiluted solution) or desensitizing 7II (undiluted solution) in the rinsing liquid/desensitizing liquid tank 22 and the dilution water in the diluting water tank 22' are pumped 23° to the printed printing plate that has arrived. 23', and an unused rinsing liquid or desensitizing liquid made by mixing the two is supplied from the processing liquid supply nozzle 7''.

The composition of the developer during use is as follows, and the amount of developer supplied is 300 ffll per 112 areas of the PS plate to be processed.
I made it so that

(Developer) Sodium silicate (Japanese Industrial Standard Sodium Silicate No. 3)
------100 parts thorium hydroxide ---8 parts sulfite, lithium
------4th Division Bethrex NBL (t-
Sodium butylnaphthalene sulfonate, manufactured by Kao Atlas Co., Ltd.)---10 parts Ethylene glycol monophenyl ether---7
Part water ---
--- 68111 parts Also, 1 part of water is added to the washing water tank 17.
01 and treated with circulating water for 15 seconds.

On the other hand, for treatment with a desensitizing liquid, the desensitizing liquid having the following composition is jetted from a number of nozzles so that the area of the PS plate to be treated is 100 m1' per 112, while the above-mentioned development and water washing are carried out. The treated PS plates (A) and [B] were both treated for 15 seconds.

(Degreasing agent) Gum arabic --- 40 parts Dextrin --- 160 parts 85% phosphoric acid --- 10 parts Citric acid
----25 parts 98% sodium hydroxide ----1 part water
----1000 parts Sodium dilauryl sulfosuccinate---20 parts Polyoxyethylene nonylphenyl ether (ILB=7.8)------
10 parts sorbitan fatty acid ester <1ILB=4.3)
-=-10 parts Dioctyl azelate -20 parts Oleic acid -10 parts Next, the printing plates obtained by the above development treatment were printed using a printing machine, and none of them showed any image. A high quality printed matter with no stains on the edges was obtained.

In addition, when we printed on the printing plate after processing 250 sheets of PS plate (A) and 250 sheets of PS plate [B] alternately from the beginning of processing, both showed stains in the non-printing area. No high quality prints were obtained.

Comparative Example 1 Rinse liquid/desensitizing liquid processing section 3 of the automatic processor of Example 1
The same procedure as in Example 1 was carried out except that the waste liquid tank 25 was charged with a diluted desensitizing liquid (working liquid) 101, and the waste liquid tank 25 and the processing liquid supply nozzle 7'' were connected with piping to circulate the desensitizing liquid. A similar experiment was conducted. When the obtained printing plate was subjected to a printing test, it was found that in the early stage of development, the PS plate (
There was no stain in the non-image area during printing in both A) and CB), but 1100 sheets of PS version [: A] were printed.PS version C
When the printing plates after 100 sheets of B'l were alternately treated were subjected to a printing test, stains were found in the non-image areas of all the printing plates.

Example 2 The exposed PS plates (A) and CB) were subjected to automatic ring processing (as shown in FIG. 2) using a developer having the following composition.
1111, PS version [A] and Ps version CB) are 25
Developed at 930 seconds at °C. The amount of developer supplied was 350 ml per PS plate I II2.

(Developer) Sodium silicate (Japanese Industrial Standard Sodium Silicate No. 3)
----100 parts Potassium hydroxide aqueous solution (48%) ----58 parts Sodium isopropylnaphthalene sulfonate (Aerosol O8, manufactured by American Cyanamid) ----10 parts Sodium sulfite -- ---5 parts benzyl alcohol ---20 parts water
------SOO part, on the other hand,
In the rinsing liquid/desensitizing liquid processing section 3, a rinsing liquid or a desensitizing liquid having the composition shown below is supplied in an amount of 200 s1 per 2 printing plates, and while being rubbed with a brush, the above development process is completed. PS versions (A) and CB) were each treated for 10 seconds.

(Rinse solution) Di(2-ethylhexyl)sulfosuccinic acid ester sodium salt ------30 parts Sodium dihydrogen phosphate trihydrate ---10 parts Citric acid hydrate ------ 2 parts water
------
1000 parts (desensitizing liquid) Dextrin ------78.6 parts Gum arabic ---29.0 parts 85% phosphoric acid ---30,
3-part cresol formaldehyde (number average molecular weight approximately 400) ------1,6
Part Amogen K (Dai-Kogyo Seiyaku Co., Ltd., amphoteric activator) ---0.4 parts Water ---
--For the iooo part PS plate [A], after development, it is treated with a rinsing liquid, after erasing unnecessary image areas, it is treated with a desensitizing liquid (manual preparation), and for the PS plate [B], after development, Treated with desensitizing solution.

Next, when the printing plates thus obtained were printed using a printing press, high-quality printed matter with no stains in the non-image areas was obtained in all cases. Also, the number of sheets from the beginning of processing,
Printing was also performed on the printing plates after 200 sheets of the PS plate (A) and 200 sheets of the PS plate CB) were alternately processed, and it was found that excellent printing plates with no stains in the non-image areas were obtained in both cases.

FIG. 2 is a schematic side sectional view showing the automatic developing machine used in the implementation of this example.

The entire processing apparatus consists of a development processing section 1 and a rinsing solution/desensitizing solution processing section 3.

The development processing section 1 mainly includes a development processing tank 4, a conveyance roller 5,
5', brush roller 36, aperture roller pair 8, guide plate 9
, the receiver consists of a roller 10, a developer tank 11, a developer supply nozzle 37, and a developer supply pump 12, and the developer is delivered onto the plate 23 being transported through the developer supply nozzle 37.
is supplied through the slit 37a. The used developer is squeezed by a squeeze roller pair 8 and collected into a waste liquid tank 13.

The rinsing liquid/desensitizing liquid processing section mainly includes a rinsing liquid/desensitizing liquid processing tank 20, a pair of transport rollers 5", a pair of squeezing rollers 8 degrees, a processing liquid supply nozzle 7", a roller 10 and a movable brush. The planographic printing plate that has passed through the development processing section 1 is treated with a rinsing liquid sent by a pump 23 or a desensitizing liquid sent by a pump 23' under the operation of a movable brush 21. 22a is a rinsing liquid tank, 22b is a desensitizing liquid tank, and 25 is a waste liquid tank, which are supplied from the liquid supply nozzle 7.

Comparative Example 2 In the rinsing liquid/desensitizing liquid processing section 3 of the automatic processor used in Example 2, the pumps 23 and 23' were removed, the rinsing liquid 104 was charged into the waste liquid tank 25, and the powder was supplied to the processing liquid supply nozzle. The same experiment as in Example 2 was carried out, except that the fI ring was used by pumping the plate to 7". The unnecessary image area of the obtained printing plate was erased, and then the same desensitization as in Example R!42 was carried out. After applying the liquid with a sponge, printing was performed.As a result, there was no stain in the non-image area of both 25th plates [A] and [B], but the number of sheets from the beginning of processing was 2.
After 80 sheets of the 5th plate (A) and 80 sheets of the printing plate CB) were subjected to a printing test, stains were found in the non-image areas of both plates.

〔Effect of the invention〕

According to the present invention, a high-quality lithographic printing plate can be stably obtained using a relatively small amount of developer.

Further, even when processing a large number of sheets, stable post-development processing can always be achieved. Furthermore, 25 negative and positive plates can be developed in parallel using the same automatic developing machine, and in this case, post-development processing can be carried out efficiently and continuously without changing the solution. be able to.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are automatic representation 1 used in the embodiment of the present invention.
It is a schematic nt++ sectional view of the elephant machine. 1-----1 Development processing section 2-----1 Washing processing section 3-----Rinse liquid/desensitizing liquid processing section 4-m-
Development processing tank 5,5°, 5--1 conveying roller pair 6--
---Rotating brush 7.7", 7" ---One processing liquid supply nozzle 8.8" ---One squeezing roller pair 9 ---Guide plate 10 ---Receiver is roller 11--Developing solution Storage tank 11'--
--- Dilution water tank 12.12', 18, 23.23' --- Pump 13.25 --- Waste liquid tank 14 --- Water supply pipe 15.24 --- Total changeover valve 1B --- −
-Water treatment tank 17--Wash water tank 20--Rinse liquid/desensitizing liquid treatment tank 21--Moving type brush 22-m-Rinse liquid/desensitizing liquid tank 22a-Rinse liquid tank 22b- --- Desensitizing liquid tank 22' ---
-Dilution water tank 23--One water supply pipe 34--
Heater 35-m-sensor 36----
-Brush roller

Claims (1)

[Claims] In a method of automatically transporting and developing an exposed photosensitive planographic printing plate using an automatic developing machine, substantially unused developer is added to the photosensitive lithographic printing plate for each photosensitive planographic printing plate to be processed. After the plate surface of a lithographic printing plate is supplied and developed, an aqueous solution or a desensitizing liquid containing a substantially unused surfactant is supplied to the plate surface, either through a water washing process or without a water washing process, to treat the plate surface. A method for processing a photosensitive lithographic printing plate, characterized by: