JP4344563B2 - Method for producing developer for planographic printing plate - Google Patents

Description

  The present invention relates to a method for producing a lithographic printing plate developer, and more particularly, a lithographic plate particularly useful in a so-called prospective replenishment method in which replenishment with a development replenisher is performed according to the processing area of the plate and / or the elapsed time. The present invention relates to a method for producing a printing plate developer.

Generally, an alkali-soluble resin is used as a main component in the photosensitive layer of a photosensitive lithographic printing plate, and an alkaline aqueous solution is usually used for the development process. For example, a novolac cresol resin or an acrylic resin containing an alkali-soluble portion corresponds to the alkali-soluble resin. In the development processing of the photosensitive lithographic printing plate, after imagewise exposure, the photosensitive layer corresponding to the non-image area is dissolved and removed by the developer. This development process consumes alkali in the alkaline developer, and the photosensitive layer dissolving ability gradually decreases with the processing amount of the photosensitive lithographic printing plate.
On the other hand, the alkaline aqueous solution easily absorbs carbon dioxide in the air, which also consumes the alkali in the alkaline developer and similarly reduces the dissolving ability of the photosensitive layer.
Here, this ability to dissolve the photosensitive layer is defined as the activity of the developer.
If the developer activity decreases, the photosensitive layer components become difficult to remove from the lithographic printing plate substrate, resulting in thickening of the image lines and clogging of the halftone dots. Will result.

  Therefore, in order to keep the developer activity constant throughout the running with reference to the activity of the developer at the start of processing, it is necessary to compensate for the alkali consumption due to processing and the alkali consumption due to carbon dioxide. In general, the activity can be maintained by replenishing the developer replenisher having a higher activity than the developer (development starter) charged at the start of development, but the activity can be maintained. The activity may become excessively high. In this case, the photosensitive layer components are easily dissolved and removed from the substrate of the lithographic printing plate, resulting in thin lines and halftone dots. This may cause a reduction in the number of printing sheets.

From the above, it is important to maintain the developer activity constant in the processing of the photosensitive lithographic printing plate.
Conventionally, as a method of maintaining the developer activity constant, a predetermined amount of developer replenisher is replenished per processing area of the photosensitive lithographic printing plate and / or per operation / stop time of the automatic processor. A method for keeping the activity of the developer constant has been proposed (for example, see Patent Document 1). Further, it has been shown that the replenisher is replenished intermittently or continuously as a function of the amount of PS plate processed and time (see, for example, Patent Document 2). Such a developer replenishment method is called prospective replenishment.
As a result, the activity of the developer is kept constant through running from the start of development, and stable processing becomes possible. However, if the developer replenishment system malfunctions, or the replenishment control system malfunctions, then there is no means to detect it and there is a lack of image or a non-image. The problem is not found until the remaining film is formed in the area.

In order to solve this problem, there is a method of monitoring the activity of the developer by conductivity, and an automatic processor equipped with a conductivity meter is commercially available.
However, the conductivity of the development start solution and the conductivity of the developer replaced with the replenisher (hereinafter referred to as running solution) are not always the same. In general, the conductivity of the developer decreases due to processing fatigue due to the processing of the lithographic printing plate precursor and carbon dioxide fatigue due to time lapse, but in development running, due to repeated recovery of developer activity due to replenishment of developer replenisher, The activity of the developer is kept constant. However, since the conductivity of the commonly used developer replenisher is high, the conductivity of the developing running solution tends to increase as the replacement rate of the developer replenisher increases, and eventually the developer replenisher is completely replaced by the developer replenisher. Reaching the electrical conductivity value (hereinafter referred to as the equilibrium electrical conductivity value).
Thus, it is difficult to read the activity of the developer directly from the conductivity.
Accordingly, there is a need for means that can monitor the activity of a developer simply and as accurately as possible in a process that employs developer replenishment using a prospective replenishment method.

JP-A-55-115039 Japanese Patent Laid-Open No. 11-194843 (page 8)

  An object of the present invention is to provide means for easily monitoring that the activity of a developer at the start of development is kept constant throughout the running in the development processing of a lithographic printing plate precursor by a developer replenishment method. There is.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has previously determined an equilibrium conductivity value that the running solution finally reaches, and matches the conductivity of the development start solution with the conductivity last value. Then, it has been found that it is possible to know the change in the activity of the developing solution by monitoring the conductivity of the running solution during the development running, and the present invention has been completed. That is, it has been noted that if the conductivity of the developer is constant throughout the development running, it can be considered that the activity of the developer is substantially constant.
Accordingly, the present invention is a method for producing a lithographic printing plate developer (d) for developing an image-exposed lithographic printing plate precursor,
Preparing a first development starting solution stock solution (a) and diluting the first development starting solution stock solution (a) at a predetermined dilution rate to prepare a first development starting solution (a ′);
The development replenisher (b) is replenished to the development starter (b ') so as to maintain the activity of the development starter (b'), and the development replenisher (b) is replaced with the development starter (b '). Measuring the conductivity (α) of the substituted developer (c) when the rate reaches 100%,
A second development starting solution stock solution (A) is prepared, and the second development starting solution stock solution (A) obtained by diluting the second development starting solution stock solution (A) at a predetermined dilution rate has the conductivity (α ) To produce a developer (d) by adjusting the electric conductivity of the second developing starting solution stock solution (a), as shown in FIG.

In this specification, the development starting solution means a developing solution charged into an automatic developing machine at the start of development. The developer (d) produced according to the present invention is intended to be both a developer starting solution concentrated solution that becomes a development starting solution by diluting with water, or a solution that becomes a developing start solution without being diluted.
The first development starting solution stock solution (A) means a development starting solution or a concentrated solution for developing start solution prepared according to a conventional method. If the intended developer (d) produced in the present invention is intended to be a development initiator, a development initiator prepared in accordance with a conventional method is prepared as a first development initiator stock solution (a), Is used as it is as the first development start solution (A ') without dilution. In addition, if the intended developer (d) is intended to be a developer starter concentrate, prepare a developer starter concentrate prepared according to a conventional method as the first developer starter solution (a). Then, it is diluted with water at an appropriate dilution ratio exceeding 1 time to obtain a first development starting solution (A '). Therefore, the predetermined dilution rate is in the range of about 1 to generally 15 times.
The second development starting solution stock solution (A) has the same composition as the first development starting solution stock solution (A), and the second development starting solution (A ') is also the first development starting solution. It has the same composition as (A ').

According to the production method of the present invention, the developer obtained by adjusting the electrical conductivity of the second developing starter stock solution (a) is particularly suitable for the processing area of the lithographic printing plate precursor and / or the operation of the automatic developing machine.・ Especially used when the so-called prospective replenishment system (B), which replenishes a predetermined amount of development replenisher (b) per stop time, is used effectively, and development is performed by monitoring the conductivity during the development running. The activity of the liquid can be confirmed.
In a preferred embodiment of the present invention, the electric conductivity of the second development starting solution stock solution (a) is adjusted by adding an electric conductivity adjusting agent.

  A development initiator obtained by preparing a developer according to the present invention and diluting it as necessary has an equilibrium conductivity value. Therefore, if the activity of the developer is constant throughout the running using the developer replenishment method using the development starter, the conductivity of the running developer can be regarded as substantially constant. The developer prepared according to the present invention, or the developer starting solution diluted therefrom, is particularly useful for development processing employing a prospective replenishment method, and the operator of the automatic processor indicates the conductivity of the running developer. Only by monitoring the value, the activity of the developer can be easily confirmed. During running, if the conductivity indication value of the developer deviates from the specified value, this can be easily confirmed on the monitor, and abnormalities in the replenishment amount, such as excess or shortage of replenishment amount, can be recognized at an early stage, resulting in missing or residual images. Production of a printing plate with a film can be prevented beforehand.

The present invention is described in detail below.
[Development starting solution stock solution (b) and development replenisher solution (b)]
In carrying out the present invention, the development starting solution stock solution (a) and the development replenisher solution (b) prepared are not particularly limited, but are generally alkaline aqueous solutions. These may be developer formulations that are usually used for developing a lithographic printing plate precursor, and the formulation can be appropriately selected according to the type of the image recording layer of the lithographic printing plate precursor to be processed.
Hereinafter, unless otherwise specified, the content and concentration of each component are based on the development initiator. Unless otherwise specified, the development starter and the development replenisher are collectively referred to as a developer and will be described. In addition, as for the development replenisher, the concentrated stock solution for the replenisher is usually diluted with water and supplied to the developing tank of the automatic processor, and the content and concentration of each component are diluted in the working solution. It is based on.

The developer is an alkaline aqueous solution, and can be appropriately selected from conventionally known alkaline aqueous solutions. Examples of the alkaline aqueous solution include a developer composed of an alkali silicate or a non-reducing sugar and a base, and those having a pH of 9.0 to 13.9 are generally suitable.
The alkali silicate exhibits alkalinity when dissolved in water, and examples thereof include alkali metal silicates such as sodium silicate, potassium silicate and lithium silicate, and ammonium silicate. The alkali silicate may be used alone or in combination of two or more.

The alkali aqueous solution has developability by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ and alkali oxide M ₂ O (M represents an alkali metal or ammonium group), which is a silicate component. Can be easily adjusted. Among the alkaline aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O of 0.5 to 2.0 are preferable. Within this range, there is little problem of etching a general-purpose aluminum plate or the like as a support for a lithographic printing plate precursor, which is also suitable from the viewpoint of developability. More preferably, SiO ₂ / M ₂ O (molar ratio) is 1.0 to 2.0.

  The concentration of the alkali silicate in the developer is preferably 1 to 10% by mass with respect to the mass of the aqueous alkali solution from the viewpoint of good developability and processing ability, and from the convenience of waste liquid treatment. 8 mass% is more preferable, and 3-7 mass% is the most preferable.

  In the developer comprising the non-reducing sugar and the base, the non-reducing sugar means a sugar that does not have reducibility because it does not have a free aldehyde group or ketone group, and trehalose in which reducing groups are bonded to each other. It is classified into type oligosaccharides, glycosides in which saccharide reducing groups and non-saccharides are combined, and sugar alcohols reduced by hydrogenation of saccharides. In the present invention, any of these can be preferably used.

  Examples of the trehalose type oligosaccharide include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-itit, D, L-talit, dulcit, allozulcit, meso-inocite and the like. Can be mentioned. Furthermore, maltitol obtained by hydrogenation of a disaccharide, a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide, and the like can also be suitably exemplified.

  Among the above, sugar alcohol and saccharose are preferable as the non-reducing sugar, and among them, D-sorbit, saccharose, and reduced syrup are more preferable because they have a buffering action in an appropriate pH region. These non-reducing sugars may be used singly or in combination of two or more. The proportion of the non-reducing sugar in the developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass.

  In the alkali silicate or non-reducing sugar, an alkali agent as a base can be appropriately selected from conventionally known compounds and combined. Examples of the alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Inorganic alkaline agents such as sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium borate, potassium borate, ammonium borate, potassium citrate, tripotassium citrate, sodium citrate Etc.

  Furthermore, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanol Organic alkali agents such as amicin, ethyleneimine, ethylenediamine, pyridine and the like can also be suitably exemplified. These alkali agents may be used alone or in combination of two or more.

  Of these, sodium hydroxide and potassium hydroxide are preferable. The reason is that the pH can be adjusted in a wide pH range by adjusting the amount added to the non-reducing sugar. Further, trisodium phosphate, tripotassium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they themselves have a buffering action.

  A surfactant can be added to the alkaline aqueous solution (developer) as described above. Examples of the surfactant include a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, Sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol mono fatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester , Polyglycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fat Acid diethanol amides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides and the like are preferably exemplified.

  Examples of the anionic surfactant include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid ester salts, α-olefin sulfonic acid salts, linear alkylbenzene sulfonic acid salts, branched chain Alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, disodium N-alkylsulfosuccinate monoamide Salts, petroleum sulfonates, sulfated beef tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fats Monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates Preferable examples include salts, partially saponified products of styrene / maleic anhydride copolymer, partially saponified products of olefin / maleic anhydride copolymer, and naphthalene sulfonate formalin condensates.

Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts such as tetrabutylammonium bromide, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives. Examples of amphoteric surfactants include carboxybetaines, alkylaminocarboxylic acids, alkyliminodicarboxylates, sulfobetaines, aminosulfates, imidazolines, and the like. Among the above surfactants, those having “polyoxyethylene” can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and these are also included in the surfactant. The
The concentration of the surfactant in the developer is preferably 0.001 to 10% by mass, more preferably 0.005 to 1% by mass, and most preferably 0.01 to 0.5% by mass.

The following additives can be added to the developer for the purpose of further improving the development performance. For example, neutral salts such as NaCl, KCl and KBr described in JP-A-58-75152, chelating agents such as EDTA and NTA described in JP-A-58-190952, JP-A-59- No. 121336, complexes of [Co (NH ₃ ) ₆ ] Cl ₃ , CoCl ₂ .6H ₂ O, etc., alkyl naphthalene sulfonic acid soda described in JP-A-50-51324, JP-A 55 Cationic polymers such as methyl chloride quaternized product of p-dimethylaminomethyl polystyrene described in JP-A-95946

Amphoteric polymer electrolytes such as vinylbenzyltrimethylammonium chloride and sodium acrylate copolymer described in JP-A-56-142528, reduction of sodium sulfite, etc. described in JP-A-57-192951 Inorganic salts, inorganic lithium compounds such as lithium chloride described in JP-A-58-59444, organic boron compounds described in JP-A-59-84241, and the like.
Furthermore, an ethylene oxide adduct of sugar alcohol described in JP-A-6-282079 and an alkylene oxide adduct of alkylenediamine described in JP-B-3-5430 are also useful for obtaining development stability.

Various organic solvents and the like can be added to the developer as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image portion. As the organic solvent, benzyl alcohol and the like are preferable.
Further, if necessary, an inorganic salt-based reducing agent such as hydroquinone, resorcin, sulfurous acid or sodium salt or potassium salt of bisulfite, organic carboxylic acid, antifoaming agent, and chelating agent can be added. In particular, a hard water softener described in JP-A-6-282079 is preferably used as a chelating agent.

Since the purpose of replenishment with a development replenisher is to compensate for the consumption of alkalis due to carbon dioxide and processing, the development replenisher generally has a higher alkali concentration than the development starter. The concentration is suitably in the range of 1 to 20 times the alkali concentration of the development initiator.
The surfactant concentration of the development replenisher is generally higher than that of the development initiator, but it may be supplied, for example, by elution from the image forming layer, and may be lower in some cases. A range of 0.5 to 5 times the development starter is appropriate.

[Development replenisher (b) is replenished to the development starter (b ') so as to maintain the activity of the development starter (b'), and the development replenisher (b) Step of measuring conductivity (α) of substituted developer (c) when substitution rate reaches 100%]
The development starting solution stock solution (A) prepared as described above, the development starting solution (I ') obtained at a predetermined dilution rate (1 or more and up to about 15 times), and the development replenisher ( (B), the lithographic printing plate precursor that has been image-exposed in advance is replenished with the development start solution (ii) so as to maintain the activity of the development start solution (ii) while processing a large number of sheets. The liquid (b) is replenished, and finally the conductivity value of the replacement developer (c) replaced with the development replenisher, that is, the equilibrium conductivity value is obtained.

For example, when the lithographic printing plate precursor is an infrared photosensitive type, the lithographic printing plate precursor on which an image is drawn with the same infrared intensity is continuously selected in an environment in which moisture evaporation of the development start liquid (ii) does not substantially occur. Developer replenisher (b) so that it always has the same number of clear stages or the same number of solid stages when it is processed (the number of sheets sufficient to reduce the activity of the developer by the processing of the lithographic printing plate precursor). And replenishment amount A (ml / m ² ) per unit processing area is obtained.

  Next, the development starting solution (I ′) is charged into an automatic processor, and the lithographic printing plate precursor on which an image is drawn with infrared rays is developed in an environment in which moisture evaporation of the development starting solution (I ′) does not substantially occur. The number of clear stages and / or the number of solid stages is obtained and defined as the standard developer activity. A lithographic plate in which an image is drawn with the same infrared intensity after an arbitrary time (a sufficient time for carbon dioxide gas to be absorbed and the developer's activity to be clearly reduced) after the automatic processor is in operation. To replenish the developer replenisher (b) so that the clear plate number and / or the solid plate number of the printing plate precursor are the same as the above standard, to compensate for the decrease in developer activity due to carbon dioxide absorption per unit time The replenishment amount B (ml / hour) of the development replenisher is obtained.

  Furthermore, lithographic printing in which an image is drawn with the same infrared intensity after the elapse of an arbitrary time (a sufficient time for carbon dioxide gas to be absorbed and the activity of the developer to be clearly reduced) with the automatic processor stopped. The developer replenisher (b) is replenished so that the clear plate number and / or the solid plate number of the original plate are the same as the above standard to compensate for the decrease in the developer activity due to carbon dioxide absorption per unit time in the stopped state. The replenishment amount C (ml / hour) of the development replenisher is obtained.

The replenisher A per processing area and the replenishment amount B and / or C per elapsed time thus obtained are input to the control device of the automatic developing machine. Then, the sequence of the automatic processor is replenished by the replenishment amount A for every predetermined processing area (for example, every 5 m ² ), for example, and every predetermined time (for example, one hour) If processing is performed so that the replenishment amount B and / or C is replenished every time), the activity of the running liquid is kept substantially constant. In this way, the running is continued, and finally the development replenisher (b) is replaced with the development replenisher (b) (the replacement rate of the development replenisher (b) with respect to the development replenisher (b)) is 100. The conductivity value of the replacement developer (c) when the value is%) is the equilibrium conductivity value (α).

[A second development starting solution stock solution (a) is prepared, and the second development starting solution (a ') obtained from the second development starting solution stock solution (a) at the predetermined dilution rate has the electric conductivity. A step of producing a developer (d) by adjusting the electrical conductivity of the second development starting solution stock solution (b) as indicated by (α)]
The equilibrium conductivity value (α) can be obtained as described above, and the following operation is performed using this conductivity value.
As the second development starting solution stock solution (A), the same one as the first development starting solution stock solution (A) is prepared. Here, the second development start solution (A ′) means that the first development start solution stock solution (A) is the first development start solution (A ′) as it is in the previous operation. The second development starting solution stock solution (A) becomes the second development starting solution (A ') as it is. Alternatively, if the first development starting solution stock solution (a) is diluted and the first development starting solution (a ′) is prepared in the previous operation, the second development starting solution (a ′) No. 2 development starting solution stock solution (A) is obtained at a predetermined dilution rate (over 1 to about 15 times). The electric conductivity of the second developing start solution undiluted solution (A) is adjusted so that the second developing start solution (I ') shows the equilibrium conductivity value (α). More specifically, it is preferable to show a value in the range of ± 2 mS / cm of the equilibrium conductivity value (α). In this way, the conductivity value of the second developing starting solution stock solution (a) is adjusted, and the developing solution (d) intended by the present invention is obtained.

The above-described conductivity adjustment can be carried out by adding a conductivity adjusting agent to the development starting solution stock solution (A).
As the conductivity adjusting agent that can be used in the present invention, inorganic and organic electrolytes can be used. Inorganic electrolytes include hydrochlorides such as lithium, sodium, potassium, calcium, magnesium and ammonium, sulfates, nitrates, phosphates, carbonates, nitrites, sulfites, phosphites, bisulfites, bisulfites, Bicarbonate etc. are mentioned. As the organic electrolyte, carboxylic acid salts of cation such as lithium, sodium, potassium, calcium, magnesium and ammonium, sulfonate and phosphonate are used. More specifically, carboxylates such as formate, acetate, propionate, butanoate, succinate, malonate, succinate and citrate, benzoate, salicylate, sulfosalicylate and Preferred are directional carboxylates such as phthalates, sulfonates such as lower alkyl sulfonates, benzene sulfonates, styrene sulfonates, xylene sulfonates, lower alkyl benzene sulfonates, and benzene disulfonates. Take as an example.
Among these conductivity adjusting agents, carbonates and citrates are particularly preferable because they can increase the conductivity by adding a relatively small amount.
In addition, when a conductivity adjusting agent is added, the activity of the development starting solution may change. In this case, the alkali concentration of the development starting solution is increased or decreased to return to the original activity, and the conductivity value including that is adjusted to the range of the equilibrium conductivity value ± 2 mS / cm.

The developer prepared by the method of the present invention is particularly preferably used together with the development replenisher (b) for processing employing a prospective developer replenishment method.
The prospective replenishment method can be carried out in accordance with a conventional method, and the automatic processor for carrying out the method is not particularly limited as long as the prospective replenishment method can be carried out and equipped with a conductivity meter. The position of the sensor of the conductivity meter may be any place where it can be immersed in the developer at the time of measurement and the conductivity of the developer can be measured. For example, the developer circulation system of the automatic processor, particularly in the developer tank or the circulation pipe The inside is a preferred position.
The developer produced by the method of the present invention is diluted at a predetermined dilution rate as necessary, charged into the developing tank as a development start solution, and after the development process is started, the developer is replaced with the development replenisher Monitor the conductivity.

The lithographic printing plate precursor to be treated with the developer produced according to the present invention is not particularly limited, and is provided with an image recording layer such as a photosensitive layer and a heat-sensitive layer exemplified below on a support. Suitable examples of the image recording layer include a conventional positive type, a conventional negative type, a photopolymer type, a thermal positive type, and a thermal negative type. The conventional here refers to a conventional lithographic printing plate precursor which is a conventional lithographic printing plate that is imagewise exposed through a transparent positive image or a transparent negative image. Hereinafter, these suitable image recording layers will be described.
<Conventional positive type>
A preferable example of a conventional positive photosensitive resin composition is a composition containing an o-quinonediazide compound and an alkali-soluble polymer compound. Examples of o-quinonediazide compounds include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, and US Pat. No. 3,635,709. There are esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol acetone resin as described. Examples of the alkali-soluble polymer compound include phenol / formaldehyde resin, cresol / formaldehyde resin, phenol / cresol / formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, Examples thereof include carboxy group-containing polymers described in Japanese Patent No. 36184. Further, acrylic resins containing phenolic hydroxy groups as described in JP-A-51-34711, acrylic resins having sulfonamide groups as described in JP-A-2-866, and urethane Various alkali-soluble polymer compounds such as resins can also be used. Further, the photosensitive resin composition includes compounds such as sensitivity modifiers, printing agents, dyes and the like disclosed in JP-A-7-92660 [0024] to [0027] and those disclosed in the same publication [0031]. It is preferable to add a surfactant for improving the coatability.

<Conventional negative type>
Examples of conventional negative photosensitive resin compositions include those containing a diazo resin and an alkali-soluble or swellable polymer compound (binder).
Examples of the diazo resin include a condensate of an aromatic diazonium salt and an active carbonyl group-containing compound such as formaldehyde. Further, for example, a condensate of p-diazophenylamines and formaldehyde and hexafluorophosphate or An organic solvent-soluble diazo resin inorganic salt that is a reaction product with tetrafluoroborate is exemplified. In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable. Suitable binders include copolymers containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as essential components, for example, 2-hydroxyethyl (meta) as described in JP-A-50-118802. ) Acrylate, (meth) acrylonitrile, multi-component copolymers of monomers such as (meth) acrylic acid, alkyl acrylate, (meth) acrylonitrile, and unsaturated as described in JP-A-56-4144 Mention may be made of multi-component copolymers composed of carboxylic acids. Further, the photosensitive resin composition is a plasticizer for imparting the flexibility and wear resistance of the baking agent, dye, and coating film disclosed in JP-A-7-281425 [0014] to [0015]. It is preferable to add a compound such as a development accelerator and a surfactant for improving the coating property.
As a lower layer of the above-mentioned conventional type positive type or negative type photosensitive layer, a polymer compound having a component having an acid group and a component having an onium group described in JP-A-2000-105462 is used. It is preferable to provide an intermediate layer to be contained.

<Photopolymer type>
(Photosensitive layer)
A photopolymer type photopolymerizable photosensitive composition (hereinafter referred to as “photopolymerizable composition”) is an addition-polymerizable ethylenically unsaturated bond-containing compound (hereinafter simply referred to as “ethylenically unsaturated bond-containing compound”). And a photopolymerization initiator and a polymer binder as essential components, and if necessary, various compounds such as a colorant, a plasticizer, a thermal polymerization inhibitor and the like.
The ethylenically unsaturated bond-containing compound contained in the photopolymerizable composition is such that, when the photopolymerizable composition is irradiated with actinic rays, it undergoes addition polymerization by the action of the photopolymerization initiator, and is crosslinked and cured. It is a compound having an ethylenically unsaturated bond. The ethylenically unsaturated bond-containing compound can be arbitrarily selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more, such as monomers, prepolymers (ie, dimers). Trimers and oligomers), mixtures thereof, and copolymers thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic polyhydric compounds. And amides with a polyvalent amine compound. Urethane addition polymerizable compounds are also suitable.

As the initiator contained in the photopolymerizable composition, various photopolymerization initiators or a combination system (photoinitiation system) of two or more photopolymerization initiators are appropriately selected and used depending on the wavelength of the light source used. For example, the initiation system shown in JP-A-2001-22079 [0021] to [0023] is preferred. The polymer binder contained in the photopolymerizable composition not only functions as a film-forming agent for the photopolymerizable composition, but also needs to dissolve the photosensitive layer in an alkali developer. An organic high molecular weight polymer that is swellable is used. As the polymer, those shown in the publications [0036] to [0063] are useful. In addition, it is also preferable to add an additive (for example, a surfactant for improving the coating property) shown in the publications [0079] to [0088] to the photopolymerizable composition.
Further, it is preferable to provide an oxygen-blocking protective layer on the photosensitive layer in order to prevent the oxygen polymerization inhibiting action. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and its copolymer. Furthermore, it is also preferable to provide an intermediate layer or an adhesive layer as shown in JP-A-2001-228608 [0124] to [0165] as the lower layer of the photopolymer type photosensitive layer.

<Thermal positive type>
(Thermosensitive layer)
The thermal positive type heat-sensitive layer contains an alkali-soluble polymer compound and a photothermal conversion substance. This alkali-soluble polymer compound includes a homopolymer containing an acidic group in the polymer, a copolymer thereof, and a mixture thereof. In particular, an acidic group such as the following (1) or (2) is included. It is preferable from the viewpoint of solubility in an alkali developer: (1) phenolic hydroxy group (—Ar—OH), (2) sulfonamide group (—SO ₂ NH—R). In particular, it is preferable to have a phenolic hydroxy group from the viewpoint of excellent image formability upon exposure with an infrared laser or the like, for example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m− / p−. Preferable examples include mixed cresol formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) mixed formaldehyde resin and the like, and pyrogallol acetone resin. More specifically, the polymers shown in [0023] to [0042] of JP-A No. 2001-305722 are preferably used.

The photothermal conversion substance converts exposure energy into heat and can efficiently cancel the interaction of the exposed area of the heat sensitive layer. From the viewpoint of recording sensitivity, a pigment or dye having a light absorption region in the infrared region with a wavelength of 700 to 1200 nm is preferable. As a dye. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes (for example, A dye such as a nickel thiolate complex) can be used. Among these, cyanine dyes are preferable, and examples thereof include cyanine dyes represented by general formula (I) in JP-A No. 2001-305722. In the composition of the thermal positive type, it is preferable to add a sensitivity control agent, a printing agent, a compound such as a dye similar to those described for the conventional positive type, and a surfactant for improving the coating property. Specifically, the compounds shown in [0053] to [0059] of JP-A No. 2001-305722 are preferable.
The thermal positive type heat-sensitive layer may be a single layer or a two-layer structure as described in JP-A-11-218914.
An undercoat layer is preferably provided between the thermal positive type heat-sensitive layer and the support. Examples of the component contained in the undercoat layer include various organic compounds described in JP-A-2001-305722, [0068].

<Thermal negative type>
(Thermosensitive layer)
The thermal negative-type heat-sensitive layer is a negative-type heat-sensitive layer in which the infrared laser irradiation part is cured to form an image part.
As one of such thermal negative type heat-sensitive layers, a polymerization type layer is preferably exemplified. The polymerization layer comprises (A) an infrared absorber, (B) a radical generator (radical polymerization initiator), a curing reaction caused by the generated radical (C) a radical polymerizable compound, and (D) a binder. Containing polymer.
In the polymerization layer, the infrared rays absorbed by the infrared absorber are converted into heat, and the generated heat decomposes radical polymerization initiators such as onium salts to generate radicals. The radically polymerizable compound is selected from compounds having a terminal ethylenically unsaturated bond, and a polymerization reaction is caused in a chain by the generated radicals and is cured. Examples of the infrared absorber (A) include the above-described photothermal conversion substance contained in the above-described thermal positive type heat-sensitive layer. In particular, as a specific example of the cyanine dye, paragraph number of JP-A No. 2001-133969 [0017] to [0019] may be mentioned. Examples of the radical generator (B) include onium salts. Specific examples of onium salts that can be suitably used are described in paragraphs [0030] to [0033] of JP-A No. 2001-133969. Things can be mentioned. (C) The radically polymerizable compound is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. (D) It is preferable to use a linear organic polymer as the binder polymer, and a linear organic polymer that is soluble or swellable in water or weak alkaline water is selected. Of these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxy group in the side chain is particularly preferable because of its excellent balance of film strength, sensitivity, and developability. With respect to (C) the radical polymerizable compound and (D) the binder polymer, those described in detail in the publications [0036] to [0060] can be used. As other additives, it is also preferable to add an additive (for example, a surfactant for improving coating properties) shown in the publications [0061] to [0068].

  In addition to the polymerization type, an acid-crosslinking type layer is preferably used as one of the thermal negative type heat-sensitive layers. The acid cross-linking layer comprises (E) a compound that generates an acid by light or heat (hereinafter referred to as “acid generator”) and (F) a compound that cross-links by the generated acid (hereinafter referred to as “cross-linking agent”). And (G) an alkali-soluble polymer compound that can react with a crosslinking agent in the presence of an acid. In order to efficiently use the energy of the infrared laser, (A) an infrared absorber is blended in the acid crosslinking layer. Examples of the acid generator (E) include compounds capable of generating an acid upon thermal decomposition, such as a photoinitiator for photopolymerization, a photochromic agent for dyes, and an acid generator used for a microresist. . (F) The crosslinking agent includes (i) an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group, (ii) a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group, Or (iii) an epoxy compound is mentioned. (G) Examples of the alkali-soluble polymer compound include novolak resins and polymers having a hydroxyaryl group in the side chain.

<Support>
As a support for a lithographic printing plate precursor provided with the image recording layer, an aluminum plate is generally used. The aluminum plate is a plate-like body such as pure aluminum or an aluminum alloy containing aluminum as a main component and containing a small amount of foreign atoms. Such heteroatoms include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the like. As the alloy composition, a foreign atom content of 10% by mass or less is appropriate. The preferred aluminum is pure aluminum, but completely pure aluminum is difficult to produce by refining technology, so it is preferable that it contains as few foreign atoms as possible. Moreover, it can be said that it is a raw material which can be used for this invention if it is an aluminum alloy of the foreign atom content rate of the extent mentioned above. The composition of the aluminum plate is not particularly limited, and conventionally known and publicly available materials can be used as appropriate. Preferred materials include JIS A 1050, 1100, 1200, 3003, 3103, and 3005. The thickness of the aluminum plate used in the present invention is suitably about 0.1 mm to 0.6 mm. Prior to roughening the aluminum plate, a degreasing treatment for removing the rolling oil on the surface, for example, with a surfactant or an alkaline aqueous solution is performed as necessary.
Next, roughening treatment, anodic oxidation treatment, hydrophilic treatment and the like are performed in an appropriate combination. For example, there is a support treatment method as disclosed in JP-A-2001-356494.

A lithographic printing plate precursor can be obtained by coating an image recording layer on such a support, but an intermediate layer may be provided before coating the image recording layer. A material containing an organic polymer compound is often used as such an intermediate layer, for example, one disclosed in JP-A-2001-356494.
On the back surface of the lithographic printing plate precursor, a coating layer made of an organic polymer compound (also referred to as “backcoat layer”) is provided on the back surface of the lithographic printing plate precursor, if necessary, in order to prevent the image recording layer from being scratched when stacked. be able to.

〔exposure〕
Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Also, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are used. Examples of the laser beam include a helium / neon laser, an argon laser, a krypton laser, a helium / cadmium laser, and a KrF excimer laser. In the laser direct-drawing type printing plate, a light source having an emission wavelength from the near infrared to the infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.
Hereinafter, the present invention will be described in detail with reference to examples.

An aluminum plate (material 1050) having a thickness of 0.3 mm was washed with trichlorethylene and degreased, then this surface was grained using a nylon brush and 400 mesh pumice-water suspension, and washed thoroughly with water. . This aluminum plate was etched by being immersed in a 25% aqueous sodium hydroxide solution at 45 ° C. for 9 seconds, washed with water, then further immersed in a 20% nitric acid aqueous solution for 20 seconds, and washed again with water. At this time, the etching amount of the grained surface was about 3 g / m ² .
Next, this aluminum plate was provided with a direct current anodic oxide coating of 3 g / m ² at a current density of 15 A / dm ² using 7% sulfuric acid as an electrolytic solution, and then washed and dried.
This was hydrophilized with a 2.5% aqueous solution of sodium silicate at 30 ° C. for 10 seconds, coated with the following undercoat layer coating solution, and dried at 80 ° C. for 15 seconds to form a support layer on which the undercoat layer was formed. Obtained. The coating amount of the undercoat layer after drying was 15 mg / m ² .

<Coating liquid for undercoat layer>
The following copolymer (molecular weight 28000) 0.3g
Methanol 100g
1g of water

On the undercoat layer of the obtained support, the following image forming layer coating solution [a] was applied so that the coating amount was 1.8 g / m ² , and a heat-sensitive positive lithographic printing plate [A ] Was obtained. This was cut into a size of 1003 mm × 800 mm to prepare a large number of sheets.
-Coating liquid for image forming layer [a]-
Copolymer 1 0.75g
m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 3,500,
0.25g containing 0.5% by mass of unreacted cresol)
p-Toluenesulfonic acid 0.003g
Tetrahydrophthalic anhydride 0.03g
Cyanine dye A (the following structure) 0.017 g
Counter ion of Victoria Pure Blue BOH
Dye converted to 1-naphthalenesulfonic acid anion 0.015g
MegaFuck F-177 (Dainippon Ink Chemical Co., Ltd.,
Fluorosurfactant) 0.05g
γ-Butyllactone 10g
Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

Cyanine dye A

Next, an automatic developing machine having an immersion type developing tank and having a conductivity sensor in the developer circulation system and capable of monitoring the conductivity of the developer was prepared. The water washing tank, which is the second bath following the developing tank of this automatic processor, is automatically supplied with tap water so that the lithographic printing plate precursor can be washed, and the finishing bath, which is the third bath. The tank was charged with 4 liters of finishing solution obtained by diluting FP-2W (Fuji Photo Film Co., Ltd.) with tap water twice.
The developing tank is charged with 20 liters of a development starting solution (a) diluted with a ratio of water 8 to 1 with a developing starting solution (a) having the following composition, kept at 30 ° C., and a development time of 12 seconds. I set it. The conductivity of the development start solution (I ') was 40 mS / cm. On the other hand, the developer replenisher stock solution tank was charged with 5 liters of the following developer replenisher stock solution. The developer replenisher (b) has a mechanism in which the developer replenisher stock solution is automatically diluted at a ratio of water 5 to 1 and replenished to the developing tank.

-Development starting solution stock solution (a)-
D-sorbitol 28% by mass
Potassium hydroxide 8.7% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
63.2% by mass of water
-Development replenisher stock solution-
D-sorbitol 20% by mass
Potassium hydroxide 9.5% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
70.4% by mass of water

[Confirmation of activity of development start solution (I ')]
A heat-sensitive positive lithographic printing plate [A] having a thickness of 1003 mm × 800 mm and a thickness of 0.3 mm was applied to the automatic processor thus prepared using a Trend setter manufactured by Creo, with a wavelength of 830 nm and a beam intensity of 2 to 10 W. Then, one plate (hereinafter referred to as a developer activity measuring plate) on which a solid image was drawn with a strength of 0.5 W and a drum rotation speed of 150 rpm was passed. The developed printing plate is observed with a magnifying glass of 25 times, the residual film at a level that does not substantially cause printing stains is evaluated, and the actual exposure energy is calculated from the exposure beam intensity at which no residual film is observed. / cm ² . This value is defined as the liquid activity of the development starting solution (A ').

[Development replenishment conditions]
A 1003 mm x 800 mm heat-sensitive positive planographic printing plate [A] (hereinafter referred to as a running plate) in which an image is exposed using a semiconductor laser with a beam intensity of 10 W at a drum rotation speed of 150 rpm using a Trend setter manufactured by Creo. ) Was prepared.
The development replenisher solution (70.5 mJ / cm ² ) obtained as described above is always maintained in the same state in this running plate in an environment in which the developer does not substantially evaporate. When 20 sheets were processed continuously while replenishing (b), the total replenishment amount was 640 ml. When this was converted into a replenishment amount A (treatment replenishment amount) per unit processing area, it was 40 ml / m ² .
Next, the development start solution (I ′) is charged into an automatic processor, and is put into operation. After 5 hours, the liquid activity (as described above) is obtained using the developer activity measuring plate. The developer replenisher (b) was replenished to maintain 70.5 mJ / cm ² ) to compensate for the decrease in developer activity due to carbon dioxide absorption. The total replenishment amount at this time is 1750 ml. From this, the replenishment amount B (ml / hour) of the development replenisher (b) per unit operating time was determined. B was 350 ml / hour.
Further, the automatic developing machine is stopped, and after 16 hours, the liquid activity (70.5 mJ / cm ² ) obtained as described above is maintained using the developer activity measuring plate. The replenisher was replenished to compensate for the decrease in developer activity due to carbon dioxide absorption. The replenishment amount after 16 hours was 1750 ml, and the replenishment amount C of the development replenisher (b) per unit stop time was 110 ml / hour.

[Running conditions]
The replenishment amounts A, B and C obtained above are input, and the replenishment amount of A every 5 m ² , the replenishment amount of B every hour, and the replenishment amount of C at the start of operation every morning. The running plate was processed for 2 months under the conditions of 50 sheets per day, an automatic developing machine operating time of 11 hours a day, and a weekly operating of 5 days. During this time, the developer activity around the 70.5mJ / cm ² of the activity of the development initiating solution (b '), a minimum 65 mJ / cm ^2, remained between the maximum 80 mJ / cm ^2, good print through running A version was obtained. However, the conductivity of the developer gradually increases from 40 mS / cm of the development start solution (A ′), and the replacement rate of the development replenisher (B) with respect to the development start solution (A ′) becomes 100%. The conductivity (α) of the substituted developer (C) reached an equilibrium state (equilibrium conductivity value) of 45 mS / cm. In other words, even if the developer activity level changes substantially constant, the conductivity level changes. Therefore, even if the conductivity value of the running solution is monitored, the liquid activity level cannot be estimated immediately.

[Preparation of developer (conductivity adjustment)]
In the same manner as described above, the development starting solution undiluted solution (α) was diluted with water in the same manner as described above so that the conductivity of the developing starting solution (α) was 45 mS / cm. Tripotassium citrate was added to (a), and the activity of the development initiator (ii) was adjusted to 70.5 mJ / cm ² to prepare a concentrate for development initiator. The composition of the concentrate for the development initiator was as follows.
-Composition of concentrated liquid for development starter-
D-sorbitol 28% by mass
Potassium hydroxide 8.4% by mass
Tripotassium citrate 11.5% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
52% by weight of water

20 liters of a development start solution obtained by diluting this concentrated solution for development start solution at a ratio of water 8 to 1 was charged and kept at 30 ° C. The conductivity of the development starting solution was 45 mS / cm, as intended.
Using the thus-prepared automatic processor, a running process was performed for two months under the same conditions as the running conditions. During this time, the developer activity remained almost constant as described above. Further, the electric conductivity of the running liquid also changed within a range of about ± 1 mS / cm from the development starting liquid of 45 mS / cm toward the equilibrium electric conductivity value of 45 mS / cm. That is, the liquid activity can be estimated from the conductivity value of the running liquid that is replaced by the development replenisher with respect to the development start liquid. For example, an abnormal state in which the development replenisher is not replenished. It becomes possible to find out before the quality trouble occurs.

  In the same manner as used in Example 1, an automatic developing machine was used, except that a development starter solution (i) -2 having the following composition was diluted in a ratio of water 8 to 1 in a developing tank ( A) 1) -2 was charged in 20 liters, kept at 30 ° C., and the development time was set to 12 seconds. The conductivity of the development initiator (ii ')-2 was 47.5 mS / cm. On the other hand, the developer replenisher stock solution tank was charged with 5 liters of the following developer replenisher stock solution. The developer replenisher (b) -2 has a mechanism in which the developer replenisher stock solution is automatically diluted at a ratio of water 8 to 1 and replenished to the developer tank.

-Composition of development starting solution stock solution (a) -2-
[SiO ₂ ] / [K ₂ O] molar ratio 1.16 potassium silicate 24% by mass
Polyethylene glycol (added mole number n = 12)
Sorbitol ether 0.2% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
75.7% by weight of water
-Composition of developing replenisher stock solution-
[SiO ₂ ] / [K ₂ O] molar ratio of 0.98 potassium silicate 31.1% by mass
Polyethylene glycol (added mole number n = 12)
Sorbitol ether 0.4% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
68.4% by mass of water

[Confirmation of activity of development starter (ii) -2]
A heat-sensitive positive lithographic printing plate [A] having a thickness of 1003 mm × 800 mm and a thickness of 0.3 mm was applied to the automatic processor thus prepared using a Trend setter manufactured by Creo, with a wavelength of 830 nm and a beam intensity of 2 to 10 W. Then, one plate (hereinafter referred to as a developer activity measuring plate) on which a solid image was drawn with a strength of 0.5 W and a drum rotation speed of 150 rpm was passed. The developed printing plate is observed with a magnifying glass of 25 times, the residual film at a level that does not substantially cause printing stains is evaluated, and the actual exposure energy is calculated from the exposure beam intensity at which no residual film is observed. / cm ² . This value is defined as the liquid activity of the development start liquid (A ')-2.

[Development replenishment conditions]
A 1003 mm x 800 mm heat-sensitive positive planographic printing plate [A] (hereinafter referred to as a running plate) in which an image is exposed using a semiconductor laser with a beam intensity of 10 W at a drum rotation speed of 150 rpm using a Trend setter manufactured by Creo. ) Was prepared.
The development replenisher solution (70.5 mJ / cm ² ) obtained as described above is always maintained in the same state in this running plate in an environment in which the developer does not substantially evaporate. B) When 20 sheets were processed continuously while replenishing -2, the total replenishment amount was 510 ml. When this was converted into a replenishment amount A (treatment replenishment amount) per unit processing area, it was 32 ml / m ² .
Next, the development start solution (I ')-2 was charged into an automatic processor, and was put into operation. After 5 hours, the solution activity obtained as described above was obtained using the developer activity measuring plate. The developer replenisher (B) -2 was replenished so as to maintain the temperature (70.5 mJ / cm ² ) to compensate for the decrease in developer activity due to carbon dioxide absorption. The total replenishment amount at this time was 1400 ml, and from this, the replenishment amount B (ml / hour) of the development replenisher (B) -2 per unit operating time was determined. B was 280 ml / hour.
Further, the automatic developing machine is stopped, and after 16 hours, the liquid activity (70.5 mJ / cm ² ) obtained as described above is maintained using the developer activity measuring plate. The replenisher was replenished to compensate for the decrease in developer activity due to carbon dioxide absorption. The replenishment amount after 16 hours was 1400 ml, and the replenishment amount C of development replenisher (B) -2 per unit stop time was 88 ml / hour.

[Running conditions]
The replenishment amounts A, B and C obtained above are input, and the replenishment amount of A every 5 m ² , the replenishment amount of B every hour, and the replenishment amount of C at the start of operation every morning. The running plate was processed for 2 months under the conditions of 50 sheets per day, an automatic developing machine operating time of 11 hours a day, and a weekly operating of 5 days. During this time, the developer activity around the 70.5mJ / cm ² of the activity of the development initiating solution (b ') -2, remained between the minimum 65 mJ / cm ^2, up to 80 mJ / cm ^2, good through-running A printing plate was obtained. However, the conductivity of the developer gradually increases from 47.5 mS / cm of the development start solution (A ')-2, and the replacement rate of the development replenisher (B) -2 with respect to the development start solution (A')-2 The conductivity (α) of the substituted developer (C) -2 when the value reached 100% reached an equilibrium state (equilibrium conductivity value) of 52.5 mS / cm. In other words, even if the developer activity level changes substantially constant, the conductivity level changes. Therefore, even if the conductivity value of the running solution is monitored, the liquid activity level cannot be estimated immediately.

[Preparation of developer (conductivity adjustment)]
Development is performed so that the conductivity of the development starting solution diluted with water is the equilibrium conductivity value (α): 52.5 mS / cm, using the development starting solution stock solution (a) -2 as described above. Tripotassium citrate was added to the starting solution undiluted solution (I) -2 and the activity of the developing solution (I ')-2 was adjusted to 70.5 mJ / cm ² to prepare a concentrated solution for developing solution. . The composition of the concentrate for the development initiator was as follows.
-Composition of concentrated liquid for development starter-
[SiO ₂ ] / [K ₂ O] molar ratio 1.16 potassium silicate 23.0 mass%
Polyethylene glycol (added mole number n = 12)
Sorbitol ether 0.2% by mass
Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% by mass
Tripotassium citrate 11.5% by mass
65.2% by mass of water

20 liters of a development start solution obtained by diluting this concentrated solution for development start solution at a ratio of water 8 to 1 was charged and kept at 30 ° C. The conductivity of the development starting solution was 52.5 mS / cm, as intended.
Using the thus-prepared automatic processor, a running process was performed for two months under the same conditions as the running conditions. During this time, the developer activity remained almost constant as described above. Further, the electric conductivity of the running liquid also changed within a range of about ± 1 mS / cm from the developing start liquid of 52.5 mS / cm to the equilibrium electric conductivity value of 52.5 mS / cm. That is, the liquid activity can be estimated from the conductivity value of the running liquid that is replaced by the development replenisher with respect to the development start liquid. For example, an abnormal state in which the development replenisher is not replenished. It becomes possible to find out before the quality trouble occurs.

Claims (1)

A method for producing a lithographic printing plate developer (d) for developing a lithographic printing plate precursor subjected to image exposure,
Preparing a first development starting solution stock solution (a) and diluting the first development starting solution stock solution (a) at a predetermined dilution rate to prepare a first development starting solution (a ′);
The development replenisher (b) is replenished to the development starter (b ′) so that the activity of the development starter (b ′) is maintained during development running, and the development running solution reaches the equilibrium conductivity value. And measuring the conductivity (α) of the replacement developer (c) when
A second development starting solution stock solution (b) having the same composition as the first development starting solution stock solution (b) is prepared, and the second development starting solution stock solution (b) is used as the first development starting solution stock solution (b). ) Is diluted with the same dilution ratio as when the second development starting solution (a ′) exhibits the conductivity (α). A method for producing a developer for a lithographic printing plate, characterized in that a developer (d) is produced by adjustment.