JPS613144A - Method for replenishing developing solution in automatic developing device of photosensitive lithographic plate - Google Patents

Abstract

PURPOSE:To enable a developing soln. to be replenished and to prevent a measuring position from being hindered with the sizes of a PS plate, a nonimage part, and image part by bringing a medium coated with a compsn. into contact with the developing soln. in a developing device, detecting a remaining amt. of coat with a photosensor, and when the remaining amt. reaches the prescribed level or more, feeding a replenishing soln. to the developing soln. CONSTITUTION:The detection medium 10 is wound on two rolls and supported above the developing soln. 5 of a developing soln. tank 6, one side of the rolls of the medium 10 is allowed to approach the other to bring the medium 10 into contact with the soln. 5 by immersion or the like. Then, the photosensor 11 approaches the medium 10 and measures a remaining amt. on the medium 10, and sends the measured result converted into an electric signal to a switching circuit 12. When the development of the PS plate proceeds and the soln. 5 deteriorates, the coat film dissolving power weakens to increase the remaining amt. Therefore, a deterioration limit of the soln., that is, the limit level of the remaining amt. can be found by investigating the relation between the remaining atm. and the deterioration degree of the soln. 5 in advance, and when the remaining amt. reaches this limit level, and the switching circuit 12 actuates the replenishing mechanism 13 to feed a prescribed amt. of the replenishing soln. from a replenishing soln. tank 14 to the tank 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for replenishing a developer replenisher in an automatic developing machine for photosensitive lithographic printing plates.

[Prior art]

BACKGROUND ART Conventionally, a photosensitive lithographic printing plate (hereinafter referred to as 28th plate) is imagewise exposed, developed using an automatic processor, and then subjected to a predetermined post-processing process to obtain a lithographic printing plate. In this case, when a large number of 28 plates are processed using an automatic developing machine, the developer in the automatic developing machine becomes exhausted and development becomes insufficient, so that the developer needs to be replenished or replaced.

As a countermeasure against this problem, conventional automatic processing machines have been equipped with an automatic replenishment mechanism for developer solution or developer replenisher, which automatically replenishes them depending on the amount of 28 plates to be processed and the time required for processing. The replenishment mechanism is designed to operate automatically.

For example, Japanese Patent Application Laid-Open No. 56-115039 describes a system that simultaneously performs replenishment corresponding to the throughput of 28 plates and replenishment corresponding to the elapsed time. Specifically, replenishment according to the throughput is automatic development. In-machine 1i: An amount of developer replenisher is replenished according to the time during which the 28 plate runs, and furthermore, a predetermined amount of developer replenisher is replenished at regular intervals. However, in this method, when replenishing according to the running time of the PS plate, only the length of the PS plate in the running direction of the PS plate is measured, so even if the width of the PS plate changes, the developer is Even if the consumed image area changes, if the length and running speed of the PS plate are constant, the same amount of developer replenisher will not be replenished, and a situation that does not suit the actual situation may occur. Also, even when replenishing over time, a fixed amount of developer replenisher is replenished at fixed intervals, so the optimal replenishment amount varies depending on the amount of developer stored in the automatic processor and the concentration of carbon dioxide gas in the air. There was a problem with this.

Furthermore, Japanese Patent Application Laid-Open No. 58-95349 discloses that the degree of elution of the non-image portion of the photosensitive layer of the PS plate is measured by a sensor located in the middle of the development zone of an automatic processor, and the degree of elution detected by this sensor is A system has been proposed in which a replenishment mechanism operates to replenish the replenisher when the rail drops to a predetermined level. This method directly measures the degree of elution from the photosensitive layer and replenishes it even if the image area changes or the carbon dioxide concentration in the working environment changes, so it has the effect of always making stable halftone dot reproduction possible. . However, this method is PS
Since it is necessary to measure the non-image area of the photosensitive layer of the plate with a sensor, the measurement position of the sensor needs to be able to measure only the non-image area, and the measurement position changes depending on the size of the PS plate to be processed. There were some inconveniences.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to solve the problem that the measurement position of the sensor is limited to the size of the PS plate and the non-image area (or image area).
To provide a replenishment method capable of detecting the degree of fatigue of a developer and replenishing a developer replenisher without being influenced by the size of the developer.

[Structure of the invention]

In the development process of developing a large number of photosensitive lithographic printing plates that have been image-irradiated by an automatic developing machine, the present invention provides a method in which the dissolution rate in the developer is equal to the dissolution rate of the photosensitive layer in the non-image area of the photosensitive lithographic printing plate. After a medium coated with the same or almost the same composition is brought into contact with a developer in an automatic processor for a certain period of time, the amount of remaining film on the medium is detected using an optical sensor. A method for replenishing developer replenisher in an automatic developing machine for photosensitive lithographic printing plates, characterized in that a certain amount of developer replenisher is added to the developer when the detected amount of residual film increases to a predetermined level or more. be.

〔Example〕

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

The development time of the PS plate is determined so that the photosensitive layer in the non-image area dissolves and the halftone dot area in the image area becomes constant. For example, positive type 2 such as 0-naphthoquinone diazide compound
When developing the 8th plate with alkaline water containing alkali metal silicate, the photosensitive layer in the non-image area is
After 10 seconds, it was almost eluted, and then development was continued for about 40 seconds to develop the fringe parts of the halftone dots in the image area, which were slow to develop.
Arrange the dots so that they have a constant area.

If the processing of the PS plate is continued in this manner, the time until the photosensitive layer dissolves becomes gradually slower, and the developer eventually deteriorates to the point where development defects are overcome.

In the present invention, in order to check the deterioration state of the developer,
A medium having a layer of a composition such that the dissolution rate in the developer is the same or almost the same as that of the photosensitive layer of the PS plate is brought into contact (immersion, spraying, etc.) with the developer for several seconds to dissolve the composition. eluting the layer and detecting the amount of layer remaining using an optical sensor tube;
As the developer deteriorates, the amount of elution decreases and the amount of remaining film does not reach a certain level (in other words, the deterioration of the developer reaches a certain limit)
After that, replenish a certain amount of developer replenisher. Although replenishment of the replenisher may be performed manually, it is of course possible and preferable to replenish the replenisher automatically.

Medium for detecting the degree of fatigue of the developer used in the present invention (
The detection medium is a transparent support such as a polyester film, or an opaque support such as water-resistant paper or metal foil, coated with the composition described above. Although it is preferable to use a powder in the form of small pieces, it is also possible to use a powder in the form of small pieces.

When the composition is coated on the above-mentioned support, the layer can be used to develop the photosensitive layer of the non-image area of the PS plate (the non-exposed area in the case of the negative 28 plate, the exposed area in the case of the positive 28 plate). Those exhibiting the same or almost the same dissolution rate as the dissolution rate in the liquid are used. The dissolution rate of the non-image area of the PS plate is negative type 28
There are differences between the negative type 28 edition and the positive type 28 edition, but the PS edition from the same shop is almost the same, so the negative type 28 edition and the positive type 28 edition are different.
It is sufficient to create detection media for two types of PS versions. The negative 28th plate generally uses a photosensitive layer containing a p-diazodiphenylamine-based photosensitive diazo compound, and the positive 28th plate uses a photosensitive layer containing an 0-quinonediazide-based photosensitive diazide compound. As the medium, a layer having the same composition as these photosensitive layers may be provided, and such an embodiment is preferable.

In the present invention, when an opaque support is used as a support for the medium, the optical sensor used to measure the degree of elution of the detection medium is a sensor that shines light from above the medium and measures the intensity of the reflected light. If the support is transparent, a light transmission sensor that measures the intensity of transmitted light is used. Also, if desired, a light reflective sensor may be used even when using a transparent support.

The PS plate used in the present invention has a photosensitive layer whose solubility changes with light irradiation (usually ultraviolet irradiation) on a substrate such as an aluminum plate, zinc plate, paper board, or plastic plate with a thickness of 0.1 to 5 gβ. It was applied on the surface. As the photosensitive layer, a photosensitive layer made of a photosensitive diazo compound, a photopolymer compound, a photopolymerizable compound, etc. is used.

The PS plate used in the present invention generally has a pH of 12
There is a negative 28 plate in which unexposed areas are eluted or swollen by a weakly alkaline developer with a pH of 12 or higher, and a negative 28 plate in which exposed areas are eluted or swollen by a strong alkaline developer with a pH of 12 or higher.

A negative 28 plate is made of an organic polymer having an acid value of 10 to 200 and a substantially water-insoluble photosensitive diazo compound (for example, a sulfonate or a Lewis acid salt of a condensate of diphenylamine-4-diazonium salt and formaldehyde). A PS plate having a photosensitive layer that is photocurable upon exposure and is provided on a support that is entirely hydrophilic is preferred.

Specific examples of organic polymers having an acid value of 10 to 200 include copolymers containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential polymerization component, such as U.S. Pat. No. 4,123,276. 2-hydroxyethyl methacrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, acrylic acid or methacrylic acid and optionally further copolymerizable monomers as described in or quaternary copolymer, acrylic acid or methacrylic acid esterified with a hydroxyl group at the end and a group that retains a dicarboxylic acid ester residue, as described in JP-A-53-120903; A copolymer with an acid or methacrylic acid and, if necessary, other copolymerizable monomers, a monomer having an aromatic hydroxyl group at the end as described in JP-A No. 54-98614 ( For example, copolymers of at least one of N-(4-hydroxyphenyl)methacrylamide), acrylic acid or methacrylic acid, and further, if necessary, other copolymerizable monomers, JP-A-56 Copolymers of alkyacrylates or methacrylates, acrylonitrile or methacrylonitrile, and unsaturated carboxylic acids as described in No. 4144 are included. Also useful are acidic polyvinyl alcohol derivatives and acidic cellulose derivatives.

On the other hand, as the photosensitive diazo compound, diazo resins represented by a condensate of p-diazodiphenylamine and formaldehyde are useful, and diazo resins that are substantially water-insoluble and organic solvent-soluble are particularly preferred. Such preferred diazo resins are described in detail in U.S. Pat. No. 3,300,309 and JP-A-54-98613. The photosensitive diazo compound is contained in the photocurable photosensitive layer in an amount of 5 to 50% by weight.
, preferably in the range of 8 to 20*.

As a positive type 28 version, 9 compounds of 0-quinonediazide and P
A photosensitive layer made of an organic polymer compound that is almost soluble in weakly alkaline water with a molecular weight of less than H12 and slightly soluble in strongly alkaline water is provided on the hydrophilic support, and when exposed to light, the exposed area becomes p.
A 28 plate having a photosensitive layer that can be dissolved by strong alkaline water of H12 or higher is desirable.

O-quinonediaside compounds include aromatic hydroxy compounds in particular. -su7toquinone diazito9 sulfonic acid ester Matasha. -゛Naphthoquinone diazide carboxylic acid esters and 0-naphthoquinone diazide sulfonic acid amide or 0-naphthoquinone diazide carboxylic acid amide of aromatic amino compounds are preferred, especially U.S. Pat.
No. 635,709, in which a condensate of pyrogallol and acetone is subjected to an ester reaction with 0-s7toquinonediazide sulfonic acid, US Pat. No. 4,028
, British Patent No. 1,494,043, which is obtained by subjecting a polyester having a hydroxyl group at the terminal to an ester reaction with 0-naphthoquinonediazide sulfonic acid or 0-nandoquinonediazidecarboxylic acid, as described in the specification of No. 111.
0-naphthoquinone diazide sulfonic acid or 0-nandoquinone cyacyto 9-oxystyrene homopolymer or copolymer of p-human 90-xystyrene with other copolymerizable monomers as described in the specification. All acid esters are reacted, and 0-7toquinone diazide is added to a copolymer of p-aminostyrene and other copolymerizable monomers as described in U.S. Pat. No. 3,759,711. Sulfonic acid or. - Naphthoquinonediazidecarboxylic acid subjected to amide reaction is very good.

Examples of organic polymer compounds soluble in strong alkaline water used in combination with these O-quinonediazide compounds include novolac type phenol resins. Specifically, phenol formaldehyde resin, 0-cresol formaldehyde 9 resin, m-cresol formaldehyde resin, etc. are included. Furthermore, as described in JP-A-50-125806, in addition to the above-mentioned phenol resins, phenol substituted with an alkyl group having 3 to 8 carbon atoms such as t-methylphenol formaldehyde resin or cresol and formaldehyde can be used. It is even more preferable to use a condensate with. The organic polymer compound soluble in strong alkaline water is contained in the photosensitive layer in an amount of about 50 to about 85% by weight, preferably 60 to 80% by weight.

In the case of any of the above 28 plates, when an aluminum plate or the like is used as a support, it is necessary to have good adhesion to the photosensitive layer.
For the purpose of improving the printing durability of the plate, it is preferable to subject the aluminum plate to a surface treatment such as graining, anodizing, anodizing, or the like.

The developing solution consisting of slightly alkaline water with a pH of less than 12 used in the present invention is disclosed in JP-A-51-77401 and JP-A-51-80.
No. 228, No. 53-44202 and No. 55-520
anionic surfactants, such as those described in No. 54;
An aqueous solution consisting of an organic solvent having a solubility in water of 10% by weight or less at room temperature, an alkaline agent, water, and, if necessary, an antifouling agent, is suitable.

Examples of the anionic surfactant in the developing solution containing weakly alkaline water used in the present invention include sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, dibasic sodium, and alkyl sulfate.
Higher alcohol sulfate ester salts having 8 to 22 carbon atoms such as ade, aliphatic alcohol phosphate ester salts such as sodium salt of cetyl alcohol phosphate, for example sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid ,
alkylaryl sulfonates such as the sodium salt of metanitrobenzenesulfonic acid, e.g. C17H;
Sulfonic acid salts of alkylamide 9 such as 33CON(CH3)CH2cH2so3Na and the like.

For example, sodium sulfoko (acid dioctyl ester,
These include sulfonic acid salts of dibasic fatty acid esters such as sodium sulfosuccinate dihexyl ester.

The anionic surfactant is added in the developer solution at the time of use.
It is appropriate to contain it within a range of % by weight. 0.
If the amount decreases by 1% by weight, the effectiveness of its use will decrease.
If the amount is higher than 5% by weight, for example, the dye contained in the photocurable photosensitive layer may elute (color loss) excessively, and the mechanical damage such as the abrasion resistance of the photocured image may be affected. , the chemical strength may be deteriorated.Therefore, the preferred amount used is in the range of 0.5 to 1.5% by weight.

The organic solvent used in the weakly alkaline aqueous developer used in the present invention is suitably selected from those having a solubility in water of about 10% by weight or less, preferably about 2% by weight or less. Examples of such organic solvents include 1-phenylethanol, 2-phenylethanol, 3-phenylpronominol-1°4-phenyltutanol 1,4-phenylmethanol-2,2-phenylmethanol-11
, 2-phenoxyethanol, 2-benzyloxyethanol, 0-methoxybenzyl alcohol, p-methoxybenzyl alcohol, indyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol, and 3-methylcyclohexanol. be able to.

The content of the organic solvent in the developer is preferably 1 to 5% by weight. The amount used is closely related to the amount of surfactant used, and it is preferable that the amount of surfactant increases as the amount of organic solvent increases. This is because if the amount of surfactant is small (or if a large amount of organic solvent is used, the organic solvent will not be dissolved, and therefore good image expression cannot be expected to be ensured).

Examples of alkaline agents that can be used in the developing solution of weakly alkaline water used in the present invention include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, tertiary sodium phosphate, dibasic sodium phosphate, and tertiary sodium phosphate. Inorganic alkaline agents such as ammonium phosphate, diammonium phosphate, sodium metasilicate, sodium bicarbonate, sodium borate, ammonium borate, ammonia, etc., and monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine. Organic aminated metals such as carbon dioxide, diisopropylamine, n-butylamine, monoethanolamine, jetanolamine, triethanolamine, monoisopronozonolamine, diisopropanolamine, ethyleneimine, ethylene cyanide, pyridine, etc. These can be used alone or in combination. The content of alkaline agent in the developer is 0.0
5-3% by weight is suitable, preferably 0.1-1% by weight. If the amount is less than 0.05% by weight, the removal of the uncured photosensitive layer will be incomplete. On the other hand, if it is more than 3% by weight, the mechanical and chemical strength of the photocured portion of the photosensitive layer will deteriorate. For example, in the case of lithographic printing plates, this appears as a decrease in printing durability.

The remaining component of the developer of the present invention is water, and may further contain various additives known in the art, if necessary. For example, sodium sulfite and sodium salt of sulfopyrazolone are used as antifouling agents, and ethylenediaminetetraacetic acid 4Na salt and N%CHz are used as water softeners.
COONa)s can be added.

The developing solution for a positive 28 plate in which exposed areas are eluted or swollen by strong alkaline water with a pH of 12 or more used in the present invention is an alkali metal hydroxide, an alkali metal silicate, an alkali metal sulfate, or an alkali metal aluminate. , water and optionally surfactants and other additives.
Two or more strong alkaline aqueous solutions are preferred. Specifically, JP-A-48-15535, JP-A No. 53-82334, JP-A No. 5
No. 4-62004, No. 52-127338, No. 53-
No. 96307, No. 50-144502, No. 55-22
No. 759, No. 55-251QO, No. 55-9594
No. 6.

Examples include developing solutions made of sodium silicate or potassium silicate, which are described in No. 55-115039, No. 56-142528, and No. 50-51324.

Next, embodiments of the present invention will be described with reference to the drawings.

The drawing is a schematic diagram showing an example of an automatic developing machine used to carry out the present invention.

The imagewise exposed 28 plate 1 is processed by continuously moving the development zone by means of transport rolls 2.3.4.

The developer 5 is sent from the developing tank 6 to the 28th plate from the spray tube 8 above the 28th plate by the pump 7, and is circulated to the developing tank and psH1 development is performed.

No. 9 is Norashirol, which completely removes the photosensitive layer that could not be removed by developer spray alone. Developed PS
The plate is made into a printing plate after being washed with water, gummed, dried, etc.

Reference numeral 10 denotes a detection medium according to the present invention, which is shown in the form of a wedge in this example, is wound around a roll and supported, and is provided at an appropriate position above the developer 5 in the developer tank 6. The medium is brought into contact with the developer for a certain period of time (about 2 to 10 seconds) by bringing one roll of the detection medium close and immersing the medium in the developer, or by spraying the developer by an appropriate means.

Next, the medium is separated from the developer, and the state of the remaining film on the medium is measured by an optical sensor 11 provided close to the medium, and this is preferably converted into an electrical signal and sent to a switch circuit ratio. . As the development of the PS plate progresses and a large number of PS plates are processed, the developer gradually deteriorates, and its ability to dissolve the medium layer becomes weak, resulting in a large amount of residual film.
The relationship between the amount of remaining film and the degree of deterioration of the developer 1. If you investigate this in advance, you will be able to know the deterioration limit of the developer that requires replenishment of the replenisher, that is, the rail of the amount of remaining film on the medium. can. When the remaining film amount reaches this rail, the replenishment mechanism 13 is operated according to the switch circuit ratio to replenish the developer tank 6 with a certain amount of developer replenisher from the replenishment tank 14.

In the above example, the developing device may be different depending on whether the PS plate is a negative type or a positive type, or the developing solution may be replaced in the same device. When the detection medium has a photosensitive layer similar to that of the PS plate, the medium used for replenishing the developer of the negative 28 plate is brought into contact with the developer while remaining unexposed, but at the time of contact, a certain brush roll etc. Preferably, the surface of the medium is rubbed.

In the case of a developer for a positive type 28 plate, the medium is exposed to ultraviolet light or the like and then brought into contact with the developer.

The frequency of contacting the medium with the developer may be about every 10 to 20 minutes when processing PS plates continuously.
Preferably, all these operations are performed automatically.

〔Effect of the invention〕

According to the present invention, by simply providing a detection medium with a small area, it is possible to easily know the deterioration limit of the developer and replenish the developer without affecting the size of the PS plate, the image area, etc. Further, the medium itself is eluted by the developer, but since the area of the medium is small, the deterioration of the developer caused by this is completely negligible and does not adversely affect the development of the PS plate.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an example of an automatic developing device used to carry out the present invention. 1...PS version 2.3.4...Transport roll 6...Developing tank 8...Nozzle 9...Brush roll 10...Detection medium procedure amendment document November 3, 1980 Showa Relationship with 1959 Patent Application No. 125611 case,
Name of Patent Applicant (520) Fuji Photo Film Co., Ltd. Kasumigaseki Building Post Office P.O. Box No. 49 No. 7 The column for the subject of amendment "Detailed explanation of the invention in the specification" will be amended as follows. 1) Correct "alkyacrylate" in the second line of page 10 to "alkyl acrylate". 2) On page 11, line 16, "reacted" is corrected to "reacted." 6) On page 19, 1°, line 6, amend "When it deteriorates," to "When it deteriorates." 4) On page 20, line 16, after “contact.”
If you use a medium coated with an organic polymer compound soluble in alkaline water that has the same dissolution speed as the exposed portion of the photosensitive layer of the plate. Exposure of the medium to ultraviolet light becomes unnecessary and is more preferred. ” to join.

Claims (1)

[Claims] (1) In the development step of developing a large number of image-exposed photosensitive lithographic printing plates using an automatic developing machine, the dissolution rate in the developer is the same as the dissolution rate of the photosensitive layer in the non-image area of the photosensitive lithographic printing plate. After a medium coated with almost the same composition is brought into contact with a developer in an automatic processor for a certain period of time, the amount of film remaining on the medium is detected using an optical sensor, and the amount detected by the sensor is A method for replenishing a developer replenisher in an automatic developing machine for photosensitive lithographic printing plates, characterized in that a certain amount of developer replenisher is added to the developer when the amount of remaining film increases to a predetermined level or more.