JP2005338731A - Replenishing method for developer replenisher in automatic developing machine for photosensitive planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a replenishing method for a developer replenisher in an automatic developing apparatus for a photosensitive planographic printing plate, by which fluctuation in the sensitivity of a developer solution with changes in the developing conditions of the developer containing an electrolyte and a development restrainer can be suppressed to minimum although a developing section of an automatic developing apparatus has a simple and inexpensive constitution in a conductivity based replenishing system. <P>SOLUTION: The replenishing method for a developer solution in an automatic developing apparatus includes: developing a great number of exposed photosensitive planographic printing plates with a developing solution containing an electrolyte and a development restrainer; and keeping the activity of the developing solution constant. In the method, conductivity of a developing solution is measured; the conductivity of the developing solution is compared with a preliminarily determined conductivity reference; and when the conductivity of the current developing solution is lower than the conductivity reference, the developing solution is replenished with a developer replenisher having higher conductivity than the developing solution and with a developer replenisher having higher concentration of the development restrainer and higher conductivity than the developing solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, an automatic development method for a photosensitive lithographic printing plate and an automatic development apparatus thereof, and in particular, the change in developer sensitivity with respect to a change in development processing conditions of a developer containing a development inhibitor is more conductive than the developer. The present invention relates to a technique for minimizing the concentration by replenishing with a replenisher having a higher development inhibitor concentration and higher conductivity than a replenisher and developer having a higher conductivity.

  In recent years, the development of lasers has been remarkable. Especially, solid lasers and semiconductor lasers with light emitting regions from near infrared to infrared are easily available in high output and small size. These lasers are very useful as exposure light sources for the system. As an image recording material suitable for laser writing, for example, JP-A-7-285275 discloses a binder such as cresol resin, a substance that generates heat by absorbing light, and a thermal decomposable material such as quinonediazide. In addition, there has been proposed a positive type image recording material containing a compound which can substantially reduce the solubility of the binder in a state before decomposition. This is a substance that generates heat by absorbing the light in the exposed area by near-infrared irradiation, and makes the exposed area alkali-soluble (heat mode type). Therefore, the thermal efficiency is low, and the solubility in an alkali developing solution in the development process is not satisfactory. For this reason, the alkali concentration of a developing solution was raised and the solubility of the exposed part has been ensured. However, the heat mode type lithographic printing plate precursor has low resistance to alkali developing solution in the image area under the high concentration alkaline conditions as described above, and dissolves with only slight scratches on the surface of the image recording material. As a result, there are problems such as defects in the image area. In particular, the tendency was more remarkable in a positive type lithographic printing plate precursor using a polymer compound that is highly soluble in an alkaline aqueous solution. Therefore, there is a limit to increasing the alkali concentration of the alkali developer so that no residual film is formed in the non-image area, and it is difficult to form a sharp and clear image without causing defects in the formed image area. Met. In particular, in a fine image including a dot portion and a thin line, it is required to increase the sharpness and improve the reproducibility. Therefore, in the photosensitive lithographic printing plate automatic developing device, as a technique for managing the sensitivity of the developer, the developer replenisher is replenished over time into the developing tank in which the developer is stored and the lithographic printing plate to be processed is processed. The plate area is measured and the amount of development replenisher according to the measured value is replenished over time. A replenishment method is used that measures and replenishes the replenisher according to preprogrammed instructions.

JP-A-7-285275

However, such an area chronological reference replenishment method requires a highly accurate planographic printing plate area measuring device in the development processing section of the automatic developing device, resulting in a complicated structure and high cost. . Further, it is difficult to determine whether the lithographic printing plate has only one side or both sides (hereinafter referred to as “single side / both sides”) and the type of plate (plates having different photosensitive layer coating amounts, etc.). For this reason, if the replenishment amount of the required development replenisher changes due to changes in the plate area, single side / both sides, and plate type of the lithographic printing plate, it becomes difficult to properly replenish the development replenishment amount. there were. In addition, in the replenishment method in which the deterioration of the developer is measured by electric conductivity and the replenisher is replenished according to preprogrammed instructions, the development system that includes a development inhibitor other than the electric conductivity is a factor involved in development. Proper replenishment was difficult.
In view of such circumstances, the present invention develops an exposed photosensitive lithographic printing plate with a developer containing an electrolyte and a development inhibitor while making the developing unit of the automatic developing device simple and inexpensive. It is an object of the present invention to provide an automatic developing method of a photosensitive lithographic printing plate and an automatic developing device thereof capable of minimizing fluctuations in developer sensitivity with respect to changes in development processing conditions.

  In the present invention, the “developing replenisher” is a processing liquid that is replenished in order to keep development performance constant. In general, as this replenisher, there are those prepared by diluting the replenisher stock solution with a diluent (e.g., water) and those using the replenisher stock solution as it is without being diluted. “Liquid” means a solution prepared by diluting a replenisher stock solution with a diluent. Further, as a replenishment method, there are a method of replenishing the developer with a replenisher prepared by diluting in advance, and a method of directly replenishing the developer with a replenisher stock solution and a diluted solution separately.

  Furthermore, in the present invention, the conductivity sensor for measuring the conductivity value of the developer is a known means such as an AC conductivity meter, an AC bridge meter, or other conductivity meter. The measurement current value and oscillation frequency of the measuring device vary depending on the developer composition, etc., but the current value is low to some extent in order to prevent electrolysis of the water-soluble developer. It is preferably several hundred mA to several μA. Further, the frequency is preferably several hundred Hz to several hundred kHz from the relationship with the electrostatic capacitance component in the developer.

  The conductivity value of the developer containing the electrolyte depends on the temperature of the aqueous solution, and the value decreases as the liquid temperature increases. Therefore, it is more preferable to measure the conductivity value with a measuring instrument equipped with a temperature sensor and a temperature compensation circuit. In the control device that controls replenishment, it is also possible to compensate for the temperature by converting the actually measured liquid resistance value and liquid temperature into a conductivity value at a predetermined temperature. The sensor installation position of the AC conductivity meter, AC bridge meter, or other conductivity meter may be a place where the AC conductivity value of the developer can be measured by being immersed in the developer at the time of measurement. The developer circulation system, particularly in the developing tank or the circulation pipe is a preferable position. Moreover, as a detection part, the well-known measurement cell which used platinum, stainless steel, etc. for the electrode can be used.

  Developed when the conductivity measured when the automatic developing device is operating and / or stopped falls below the conductivity reference value calculated using the replenisher replacement rate and / or replenishment ratio and / or developer dilution rate A developer replenisher having a higher conductivity than that of the developer to compensate for the decrease in the liquid activity is replenished in the developer tank until the conductivity exceeds a reference value, and the measured conductivity value due to the processing of the photosensitive material is photosensitive. A developer replenisher with a higher developer inhibitor concentration and a higher conductivity than the developer to compensate for the decrease in developer activity when the conductivity is less than the reference value calculated from the material throughput. Then, the developer tank is replenished until it exceeds the electric conductivity reference value.

  As described above, according to the present invention, when developing a plurality of exposed photosensitive lithographic printing plates with a developer comprising an aqueous solution containing an electrolyte and a development inhibitor, the conductivity of the developer is measured. When the developer conductivity value is lower than the predetermined conductivity reference value, the developer replenisher having a higher conductivity than the developer and the developer inhibitor concentration higher than the developer and the developer having a higher conductivity. By replenishing the liquid developer replenisher, it is possible to prevent fluctuations in developer activity due to changes in processing conditions (size and type of photosensitive lithographic printing plate) despite the simple and inexpensive device configuration, and sensitivity. Automatic development processing with high stability can be realized.

First, the alkali developing solution used in the plate making method of the lithographic printing plate of the present invention will be described.
An alkali developing solution (hereinafter also simply referred to as “developing solution”) used in the developing process 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 non-reducing sugar and a base, and those having a pH of 12.5 to 14.0 are particularly preferable.
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 is easy to develop 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 adjusted to.
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 3.0 are preferable, and 1.0 to 2 0.0 is more preferable.
If the SiO ₂ / M ₂ O is less than 0.5, the alkali strength becomes stronger, which may cause a problem of etching a general-purpose aluminum plate or the like as a support for a lithographic printing plate precursor. If it exceeds 3.0, the developability may be lowered.

  Moreover, as a density | concentration of the alkali silicate in a developing solution, 1-10 mass% is preferable with respect to the mass of alkaline aqueous solution, 3-8 mass% is more preferable, and 4-7 mass% is the most preferable. If this concentration is less than 1% by mass, the developability and processing ability may be lowered. If it exceeds 10% by mass, precipitation and crystals are likely to occur, and further gelation tends to occur during neutralization in the waste liquid. , It may interfere with waste liquid treatment.

In a developer comprising a non-reducing sugar and a base, the non-reducing sugar means a saccharide that has no free aldehyde group or ketone group and therefore has no reducing property, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other. Glycosides in which saccharide reducing groups and non-saccharides are combined, and sugar alcohols reduced by hydrogenation of saccharides. Any of these can be suitably used in the present invention.
Examples of trehalose type oligosaccharides include saccharose and trehalose, and examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides.
Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. 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, as the non-reducing sugar, sugar alcohol and saccharose are preferable, and among them, D-sorbite, saccharose, and reduced starch 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 alkali agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, carbonic acid. Inorganic alkaline agents such as sodium, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium borate, potassium borate, ammonium borate, potassium citrate, tripotassium citrate, sodium citrate, etc. Is mentioned.

Furthermore, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethylene An organic alkali agent such as imine, ethylenediamine, pyridine and the like can also be suitably exemplified.
These alkaline agents may be used alone or in combination of two or more.
Of these, sodium hydroxide and potassium hydroxide are preferred. 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 have a buffering action.
The alkali developing solution of the present invention can further contain a development inhibitor from the viewpoint of exerting a dissolution inhibiting force on the image area. Examples of development inhibitors include the following alkylene oxide adducts.
[Straight chain alkylene oxide adduct]
Examples of the linear alkylene oxide adduct used in the present invention include those represented by the following general formula (I).
R-O- (A) m- (B) n-H (I)
In formula (I), R represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group, or an aryl group having 6 to 48 carbon atoms, and A and B are groups different from each other, and —CH ₂ represents either CH ₂ O— or —CH ₂ CH (CH ₃ ) O—, and m and n represent 0 or an integer of 1 to 50, provided that m and n are not 0 at the same time.

In the above formula (I), the alkyl group and alkenyl group represented by R may be branched, and the alkyl group, alkenyl group and aryl group may have a substituent. 1-20 alkyl group, halogen atom, aryl group having 6-15 carbon atoms, aralkyl group having 7-17 carbon atoms, alkoxy group having 1-20 carbon atoms, alkoxy-carbonyl having 2-20 carbon atoms Group, an acyl group having 2 to 15 carbon atoms, and the like.
In the above compound, when both A and B are present, they may be random or block copolymers. Moreover, in the compound, the total of m and n is generally 2 to 50, preferably 2 to 30, and more preferably 2 to 20.
In the above compound, when a propyleneoxy group is present, it is desirable that the compound has an acceptable water solubility.

Further specific examples of the linear alkylene oxide adduct represented by the formula (I) include those represented by the following (1) to (3).
HO- (A) m- (B) n-H (1)
CpH _{2p + 1} -O- (A) m- (B) n-H (2)
(P represents an integer of 1 to 30)
CqH _2q - ₁ -O- (A) m- (B) n-H (3)
(Q represents an integer of 2 to 30)

（Ｒ₀₁は水素原子、又は炭素原子数１〜２０の分岐していてもよいアルキル基を表す。）

(R ₀₁ represents a hydrogen atom or an optionally branched alkyl group having 1 to 20 carbon atoms.)

（Ｒ₀₁は水素原子、又は炭素原子数１〜２０の分岐していてもよいアルキル基を表す。）

(R ₀₁ represents a hydrogen atom or an optionally branched alkyl group having 1 to 20 carbon atoms.)

（Ｒ₀₁は水素原子、又は炭素原子数１〜２０の分岐していてもよいアルキル基を表す。）
上記式（１）〜（３）においてＡ、Ｂ、ｎ、ｍの定義は式（Ｉ）における定義と同義である。

(R ₀₁ represents a hydrogen atom or an optionally branched alkyl group having 1 to 20 carbon atoms.)
In the above formulas (1) to (3), the definitions of A, B, n, and m are the same as the definitions in formula (I).

Among the compounds represented by the formulas (1) to (3), a compound represented by the formula (1) is preferably used, and among them, R ₀₁ has 1 to 10 carbon atoms, preferably 1 to 1 carbon atoms. 4, more preferably an alkyl group having 1 to 3 carbon atoms.

  The molecular weight of the linear alkylene oxide adduct is generally suitably from 50 to 10,000 from the standpoint of exhibiting sufficient dissolution inhibiting power for image areas and sufficient developability for non-image areas. The molecular weight is preferably 100 to 5000, and most preferably 500 to 3500.

[Branched alkylene oxide adduct]
Here, the branched alkylene oxide adduct is a group (II) :-( A) m- (B) n-H (II) in its molecular structure.
(In the formula, A and B are different from each other, and represent either —CH ₂ CH ₂ O— or —CH ₂ CH (CH ₃ ) O—, and m and n are 0 or an integer of 1 to 50. Wherein m and n are not 0 at the same time). However, the branched alkylene oxide adduct does not include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and ethylene oxide propylene oxide condensate.
In the above compound, when both A and B are present, they may be random or block copolymers. In formula (II), the sum of m and n is generally 2 to 50, preferably 2 to 30, and particularly preferably 2 to 20.

As a specific example of the branched alkylene oxide adduct used in the present invention,
(1) Group: -O- (A) m- (B) n-H (wherein A, B, m and n are as defined in formula (II)) in the molecular structure. A compound having the above, and
(2) A group containing a nitrogen atom in the molecular structure and bonded to the nitrogen atom:-(A) m- (B) n-H (wherein A, B, m and n are represented by the formula (II) And a compound having 2 or more). In the compound (2), two or more groups:-(A) m- (B) nH may be bonded to the same nitrogen atom or may be bonded to separate nitrogen atoms. .
The branched alkylene oxide adduct used in the present invention has 2 or more, specifically 2 or more, 20 or less, preferably 10 or less, more preferably 8 or less, in the molecular structure.
The total number of moles of alkylene oxide added in the branched alkylene oxide adduct is 2 to 200 mol / molecule, preferably 2 to 100 mol / molecule, more preferably 2 to 50 mol / molecule.
In the above compound, when a propyleneoxy group is present, it is desirable that the compound has an acceptable water solubility.

As further specific examples of the branched alkylene oxide adduct used in the present invention, there are compounds represented by the following formulas (III), (IV) and (IV ′).
Compound represented by the following formula (III)

[In the formula (III), r represents an integer of 1 to 10, and R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or the following formula (II):
-(A) m- (B) n-H (II)
(In the formula (II), A and B are groups different from each other, and represent either —CH ₂ CH ₂ O— or —CH ₂ CH (CH ₃ ) O—, and m and n are 0 or 1 to 1 Represents an integer of 50, provided that m and n are not 0 at the same time), wherein at least two of R ₁ , R ₂ and R ₃ represent a group represented by the above formula (II). ]
In formula (III), r preferably represents an integer of 1 to 6, particularly preferably 1 to 4.

Examples of branched alkylene oxide adducts of formula (III) include sugar alcohols (eg, D, L-trait, D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannite, D, L-exit, D, L-talit, dulcite, allozulcitite, etc.) alkylene oxide addition compound, and glycerin alkylene oxide addition compound. These compounds are generally available on the market, and examples of commercially available products include the trade name sorbitol EO (30) (manufactured by Nikko Chemicals Co., Ltd.).
Other specific examples of branched alkylene oxide adducts include alkylene oxide adducts of polyglycerin such as diglycerin, triglycerin, tetraglycerin, pentaglycerin and hexaglycerin condensed with sugar alcohol.

  Compounds represented by formula (IV) or (IV ′)

(In the formulas (IV) and (IV ′), A and B are different groups and represent either —CH ₂ CH ₂ O— or —CH ₂ CH (CH ₃ ) O—, and m, n Represents an integer of 0 or 1 to 50, provided that m and n are not simultaneously 0 and m ′ and n ′ represent an integer of 0 or 1 to 50, provided that m ′ and n ′ are not 0 simultaneously and m ", N" represents 0 or an integer from 1 to 50, provided that m "and n" are not 0 at the same time, and m "'and n"' represent 0 or an integer from 1 to 50, provided that m "' n ″ ′ is not 0 at the same time, and in formula (IV ′), a represents an integer of 2 to 12.)

Examples of the compound represented by the formula (IV) include triethanolamine EO adduct.
Examples of branched alkylene oxide adducts represented by the formula (IV ′) include ethylenediamine EO adduct, ethylenediamine EO / PO adduct, ethylenediamine PO adduct, product catalog of Asahi Denka Kogyo Co., Ltd. And the like.
Examples of other branched alkylene oxide adducts include trimethylol propyl ether EO adduct, trimethylol propyl ether EO / PO adduct, and trimethylol propyl ether PO adduct.

  The molecular weight of the branched alkylene oxide adduct used in the present invention is generally 50 to 10,000 from the standpoint of exhibiting sufficient dissolution inhibiting power for image areas and sufficient developability for non-image areas. Is appropriate. The molecular weight is preferably 100 to 5000, and most preferably 500 to 3500.

In the alkali developing solution of the present invention, the above development inhibitors can be used alone or in combination of two or more. When the development inhibitor in the alkaline developing solution is included, the content thereof is generally 0.001 to 10.0% by mass, preferably 0.01 to 5.0% by mass, and particularly preferably 0.05 to 1.0%. % By mass.
As described above, the alkali developing solution uses a developer containing an alkali silicate or non-reducing sugar and a base, and Li ⁺ , Na ⁺ , K ⁺ , and NH ⁴⁺ are conventionally used as the cation component. In particular, a system containing a large number of cations having a small ionic radius has high penetrability into the image recording layer and excellent developability, but dissolves up to the image area and causes image defects. Therefore, there is a certain limit to increasing the alkali concentration, and in order to completely process the image recording layer (residual film) so as not to remain in the non-image area without causing defects in the image area, it is delicate. It was required to set a proper liquid condition.
However, by using a cation having a large ionic radius as the cation component, the penetrability of the developer into the image recording layer can be suppressed, and the image density can be reduced without reducing the alkali concentration, that is, the developability. The dissolution inhibiting effect of the part can also be improved.
As the cation component, in addition to the alkali metal cation and ammonium ion, other cations can be used.

The following additives can be added to the alkaline developing solution of the present invention for the purpose of further improving 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-59-121336 [Co (NH ₃ ) ₆ ] Cl ₃ , CoCl ₂ .6H ₂ O and other complexes described in JP-A-50-51324, sodium alkylnaphthalene sulfonate, n-tetradecyl-N, N-dihydroxy Anionic or amphoteric surfactants such as ethylbetaine, nonionic surfactants such as tetramethyldecynediol described in US Pat. No. 4,374,920, p described in JP-A-55-95946 -Cationic polymers such as methyl chloride quaternary compound of dimethylaminomethylpolystyrene, disclosed in JP-A-56-142528 Amphoteric polymer electrolytes such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described above, reducing inorganic salts such as sodium sulfite described in JP-A-57-192951, JP-A-58-59444 Inorganic lithium compounds such as lithium chloride described in JP-A No. 59-75255, organometallic surfactants including organic Si and Ti described in JP-A-59-75255, and organoboron compounds described in JP-A-59-84241 And quaternary ammonium salts such as tetraalkylammonium oxide described in EP101010.
A lithographic printing plate developed using an alkali developing solution and a replenisher is post-treated with a rinsing solution containing washing water, a surfactant, and the like, and a desensitizing solution containing gum arabic and starch derivatives. In this post-treatment, these treatment liquids can be combined in various ways.

The heat-sensitive positive lithographic printing plate used in the plate making method of the present invention will be described below.
[Heat-sensitive positive lithographic printing plate]
The heat-sensitive positive lithographic printing plate used in the plate-making method of the present invention comprises an image recording layer containing an infrared absorbing dye as an essential component on a support and usually containing an alkali-soluble resin or the like.
The heat-sensitive positive lithographic printing plate (also referred to as a lithographic printing plate precursor) is described in detail below. First, the configuration of the image recording layer will be described.

[Infrared absorbing dye]
In the present invention, the infrared absorbing dye used in the image recording layer is not particularly limited as long as it is a dye that absorbs infrared rays and generates heat, and various dyes known as infrared absorbing dyes can be used.
As the infrared absorbing dye, commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb infrared light or near infrared light are particularly preferred because they are suitable for use in lasers that emit infrared light or near infrared light.
Examples of dyes that absorb such infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-59240, JP-A-60-63744, etc. Examples thereof include squarylium dyes described in JP-A-58-112792, and cyanine dyes described in British Patent 434,875.

Further, a near-infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used as the dye, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A Nos. 57-142645 (US Pat. No. 4,327,169), JP-A Nos. 58-181051, 58-220143, 59-41363, and 59-84248. Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 Pentamethine thiopyrylium salts described in No. 5 and pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 As commercially available products, Epolight III-178, Epolight III-130, Epolight III-125 and the like manufactured by Eporin are particularly preferably used.
Infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993 are particularly preferred as infrared absorbing dyes used in the image recording layer. The dye exhibits a very strong interaction with the alkalinized soluble resin, and is excellent in the unexposed area alkaline development resistance of the image recording layer.

The amount of the infrared absorbing dye added to the image recording layer is 0.01 to 50% by mass, preferably 0.1 to 50% by mass, particularly from the viewpoint of sensitivity and uniformity of the image recording layer, with respect to the mass of the image recording layer. Preferably it is 0.1-30 mass%.
Specific examples of the infrared absorbing dye are shown below, but the present invention is not limited thereto.

[Alkali-soluble resin]
The alkali-soluble resin used in the image recording layer is a water-insoluble and alkali-water-soluble resin (hereinafter appropriately referred to as an alkali-soluble polymer), and has an acidic group on the main chain and / or side chain in the polymer. Containing homopolymers, copolymers thereof or mixtures thereof. Therefore, the image recording layer of the lithographic printing plate precursor has a property of dissolving when contacted with an alkaline developer.
The alkali-soluble polymer used in the image recording layer is not particularly limited as long as it is a conventionally known polymer, but any one of (1) phenolic hydroxyl group, (2) sulfonamide group, and (3) active imide group A polymer compound having a functional group in the molecule is preferable. For example, the following are exemplified, but not limited thereto.

  (1) Examples of the polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p Any of-and / or m- / p-mixing) may be mentioned, including novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. In addition to this, a polymer compound having a phenolic hydroxyl group in the side chain is preferably used as the polymer compound having a phenolic hydroxyl group. As a polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer comprising a low molecular compound having at least one unsaturated bond polymerizable with the phenolic hydroxyl group is homopolymerized, or other polymerizable property is added to the monomer. Examples thereof include a polymer compound obtained by copolymerizing monomers.

  Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenolic hydroxyl group. Specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N -(3-Hydroxyphenyl) methacrylamide, N- (4-Hydroxyphenyl) methacrylamide, o-Hydroxyphenyl acrylate, m-Hydroxyphenyl acrylate, p-Hydroxyphenyl acrylate, o-Hydroxyphenyl methacrylate , M-hydroxyphenyl methacrylate, p-hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) ethyl Acrylate, 2- 4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate can be suitably used 2- (4-hydroxyphenyl) ethyl methacrylate. Such resins having a phenolic hydroxyl group may be used in combination of two or more. Furthermore, as described in US Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin, These copolymers may be used in combination.

(2) Examples of the alkali-soluble polymer compound having a sulfonamide group include a polymer compound obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the monomer with another polymerizable monomer. . The polymerizable monomer having a sulfonamide group includes one or more sulfonamide groups —NH—SO ₂ — in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated bonds in one molecule. And a polymerizable monomer comprising a low molecular weight compound. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

(3) The alkali-soluble polymer compound having an active imide group is preferably one having an active imide group in the molecule. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer composed of one or more low-molecular compounds or by copolymerizing the polymerizable monomer with another polymerizable monomer.
As such a compound, specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

  Furthermore, as the alkali-soluble polymer compound, a polymer compound obtained by polymerizing two or more of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, and the polymerizable monomer having an active imide group is used. Alternatively, it is preferable to use a polymer compound obtained by copolymerizing these two or more polymerizable monomers with another polymerizable monomer. When a polymerizable monomer having a phenolic hydroxyl machine is copolymerized with a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imide group, the compounding polymerization ratio (mass ratio) of these components is It is preferably in the range of 50:50 to 5:95, particularly preferably in the range of 40:60 to 10:90.

  When the alkali-soluble polymer is a copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group and another polymerizable monomer The monomer that imparts alkali solubility is preferably contained in an amount of 10 mol% or more, more preferably 20 mol% or more so that the alkali solubility becomes sufficient and the effect of improving the development latitude is sufficiently achieved.

Examples of the monomer component to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the compounds listed in the following (m1) to (m12). However, the present invention is not limited to these.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

The alkali-soluble polymer compound preferably has a phenolic hydroxyl group in terms of excellent image-forming properties in exposure with an infrared laser or the like, such as phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, Preferred examples include novolak resins and pyrogallol acetone resins such as m- / p-mixed cresol formaldehyde resin and phenol / cresol (which may be m-, p-, or m- / p-mixed) mixed formaldehyde resin.
Further, as an alkali-soluble polymer compound having a phenolic hydroxyl group, as described in US Pat. No. 4,123,279, carbon such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. Examples include condensation polymers of phenol and formaldehyde having an alkyl group of 3 to 8 as a substituent.
As a copolymerization method of the alkali-soluble polymer compound, a conventionally known graft copolymerization, block copolymerization, random copolymerization method or the like can be used.

In the present invention, when the alkali-soluble polymer is a homopolymer or copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group, the weight average Those having a molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferred. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .
In the present invention, when the alkali-soluble polymer is a resin such as phenol formaldehyde resin or cresol aldehyde resin, the weight average molecular weight is 500 to 20.000, and the number average molecular weight is 200 to 10,000. preferable.
These alkali-soluble polymer compounds may be used alone or in combination of two or more, and are 30 to 99% by mass, preferably 40 to 95% by mass, particularly preferably 50%, based on the total solid content of the image forming layer. Used in an addition amount of ˜90% by mass. From the viewpoint of durability and sensitivity of the image forming layer, the above content range is appropriate.

The image forming layer may also contain an alkali-soluble polymer compound having a carboxyl group (hereinafter sometimes referred to as component (B1)).
The polymer compound (B1) may be any alkali-soluble polymer compound having a carboxyl group, but polymer compounds (b1-1) and (b1-2) defined below are preferred.
(B1-1) An alkali-soluble polymer compound having a polymerizable monomer unit represented by the following general formula (i) (hereinafter also referred to as polymer compound (b1-1))

(In the formula, Xm represents a single bond or a divalent linking group, Y represents hydrogen or a carboxyl group, and Z represents hydrogen, an alkyl group or a carboxyl group.)
As a monomer constituting the polymerizable monomer unit represented by the general formula (i), there is a polymerizable monomer having at least one carboxyl group and polymerizable unsaturated group in the molecule.
Specific examples of such polymerizable monomers include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid and itaconic anhydride.

Examples of the monomer to be copolymerized with the polymerizable monomer having a carboxyl group include the following (1) to (11), but are not limited thereto.
(1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl Alkyl acrylates such as acrylates;
(3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl Alkyl methacrylate such as methacrylate.

(4) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.

(8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.
(11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

  Moreover, the monomer of the following general formula (ii) is also preferably used.

In the formula, X represents O, S, or N—R ¹² . R ^{10 to} R ¹² each independently represents a hydrogen atom or an alkyl group. m, n, and o each independently represents an integer of 2 to 5, and C _m H _2m , C _n H _2n , and CoH _2o may each be linear or branched. p, q, and r each independently represent an integer of 0 to 3,000, and p + q + r ≧ 2.

The alkyl group in R ¹⁰ to R ^12, preferably one having 1 to 12 carbon atoms, specifically, methyl group, ethyl group, n- propyl group, an isopropyl group. p, q, and r preferably represent an integer of 0 to 500, and more preferably represent an integer of 0 to 100.
Examples of the monomer corresponding to the repeating unit represented by the general formula (ii) are listed below, but the present invention is not limited thereto.

The repeating unit represented by the general formula (ii) is a commercially available hydroxypoly (oxyalkylene) material, for example, trade name Pluronic (Pluronic (Asahi Denka Kogyo Co., Ltd.)), Adeka Polyether (Asahi Denka Kogyo Co., Ltd.) ), Carbowax (Carbowax (Glico Product)), Triton (Toriton (Rohm and Haas), and PEG (Daiichi Kogyo Seiyaku Co., Ltd.)) It can manufacture by making it react with acrylic acid, methacrylic acid, an acryl chloride, methacryl chloride, or acrylic acid anhydride by the method of this.
Separately, poly (oxyalkylene) diacrylate produced by a known method can also be used.

  Commercially available monomers include, as a hydroxyl-terminated polyalkylene glycol mono (meth) acrylate manufactured by NOF Corporation, Blemmer PE-90, Blemmer PE-200, Blemmer PE-350, Blemmer AE-90, Blemmer AE-200, Blemmer AE-400, Blemmer PP-1000, Blemmer PP-500, Blemmer PP-800, Blemmer AP-150, Blemmer AP-400, Blemmer AP-550, Blemmer AP-800, Blemmer 50PEP-300, Blemmer 70PEP-350B, Blemmer AEP series, Blemmer 55PET-400, Blemmer 30PET-800, Blemmer 55PET-800, Blemmer AET series, Blemmer 30PPT-800, Blemmer 50PPT-800, Blemmer 70PPT-800, Blemmer APT series, Blemmer 10PPB-500B, Blemmer 10APB- 500B etc. are mentioned. Similarly, as the alkyl-terminated polyalkylene glycol mono (meth) acrylate manufactured by NOF Corporation, Blemmer PME-100, Blemmer PME-200, Blemmer PME-400, Blemmer PME-1000, Blemmer PME-4000, Blemmer AME-400, Blemmer 50POEP-800B, Blemmer 50AOEP-800B, Blemmer PLE-200, Blemmer ALE-200, Blemmer ALE-800, Blemmer PSE-400, Blemmer PSE-1300, Blemmer ASEP series, Blemmer PKEP series, Blemmer AKEP series, Blemmer ANE- 300, BLEMMER ANE-1300, BLEMMER PNEP series, BLEMMER PNPE series, BLEMMER 43ANEP-500, BLEMMER 70ANEP-550, etc., and Kyoeisha Chemical Co., Ltd. Light ester MC, Light ester 130MA, Light ester 041MA, Light acrylate BO-A , Light acrylate EC-A, Light acrylate MTG-A, Light acrylate 130 A, light acrylate DPM-A, light acrylate P-200A, light acrylate NP-4EA, and light acrylate NP-8EA.

The minimum constitutional unit having a polymerizable monomer component having at least one carboxyl group and at least one polymerizable unsaturated group in the polymer compound (b1-1) is not necessarily limited to one kind, and is the same. It is also possible to use a copolymer obtained by copolymerizing two or more kinds of minimum structural units having the above acidic group or two or more kinds of minimum structural units having different acidic groups.
As the copolymerization method, conventionally known graft copolymerization, block copolymerization, random copolymerization, and the like can be used.

  (B1-2) A reaction product of a diol compound represented by the following general formula (iii), (iv) or (v) having a carboxyl group and a diisocyanate compound represented by the following general formula (viii) as a basic skeleton And an alkali-soluble polymer compound having a carboxyl group (hereinafter, also referred to as polymer compound (b1-2)).

R ¹³ represents a hydrogen atom, a substituent (for example, alkyl, aryl, alkoxy, ester, urethane, amide, ureido, halogeno are preferable), alkyl, alkenyl, aralkyl, aryl, alkoxy, aryloxy Preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an aryl group having 6 to 15 carbon atoms.
R ¹⁴ , R ¹⁵ and R ¹⁶ may have the same or different single bond and substituent (for example, alkyl, alkenyl, aralkyl, aryl, alkoxy and halogeno groups are preferred). Or a divalent aliphatic or aromatic hydrocarbon. Preferably an alkylene group having 1 to 20 carbon atoms, an arylene group having 6 to 15 carbon atoms, more preferably an alkylene group having 1 to 8 carbon atoms is shown.
If necessary, R ¹⁴ , R ¹⁵ and R ¹⁶ have other functional groups that do not react with isocyanate groups, such as ester groups, urethane groups, amide groups, ureido groups, and carbon-carbon unsaturated bonds. Also good. In addition, you may comprise a ring by 2 or 3 of R < ¹³ >, R <^14> , R <^15> , R < ¹⁶ >.
Ar represents a trivalent aromatic hydrocarbon which may have a substituent, and preferably an aromatic group having 6 to 15 carbon atoms.

OCN-R ¹⁸ -NCO (viii)
In the formula, R ¹⁸ represents a divalent aliphatic or aromatic hydrocarbon which may have a substituent (for example, alkyl, alkenyl, aralkyl, aryl, alkoxy and halogeno groups are preferable). If necessary, R ¹⁸ may have another functional group that does not react with an isocyanate group, such as an ester, urethane, amide, ureido group, or carbon-carbon unsaturated bond.

Specific examples of the diol compound having a carboxyl group represented by the general formula (iii), (iv) or (v) include those shown below.
3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (2-hydroxyethyl) propionic acid, 2,2-bis (3-hydroxypropyl) propionic acid, Bis (hydroxymethyl) acetic acid, bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, tartaric acid, N, N-bis (2-hydroxyethyl) -3-carboxy-propionamide Etc.

  The alkali-soluble polymer compound having a carboxyl group (b1-2) is preferably a reaction product in which a diol represented by the following general formula (vi) or (vii) is combined.

In the formula, R ¹⁷ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 2 or more. Examples of the alkyl group having 1 to 8 carbon atoms in R ¹⁷ include a methyl group, an ethyl group, an i-propyl group, an n-butyl group, and an i-butyl group.
Specific examples of the diol represented by the general formula (vi) or (vii) are shown below, but the present invention is not limited thereto.

Specific example of (vi)
HO-(-CH ₂ CH ₂ O-) ₃ -H
HO-(-CH ₂ CH ₂ O-) ₄ -H
HO-(-CH ₂ CH ₂ O-) ₅ -H
HO-(-CH ₂ CH ₂ O-) ₆ -H
HO-(-CH ₂ CH ₂ O-) ₇ -H
HO-(-CH ₂ CH ₂ O-) ₈ -H
HO-(-CH ₂ CH ₂ O-) ₁₀ -H
HO-(-CH ₂ CH ₂ O-) ₁₂ -H
Polyethylene glycol (average molecular weight 1000)
Polyethylene glycol (average molecular weight 2000)
Polyethylene glycol (average molecular weight 4000)
HO-(-CH ₂ CH (CH ₃ ) O-) ₃ -H
HO-(-CH ₂ CH (CH ₃ ) O-) ₄ -H
HO-(-CH ₂ CH (CH ₃ ) O-) ₆ -H
Polypropylene glycol (average molecular weight 1000)
Polypropylene glycol (average molecular weight 2000)
Polypropylene glycol (average molecular weight 4000)

Specific example of (vii)
HO-(-CH ₂ CH ₂ CH ₂ O-) ₃ -H
HO-(-CH ₂ CH ₂ CH ₂ O-) ₄ -H
HO-(-CH ₂ CH ₂ CH ₂ O-) ₈ -H
HO-(-CH ₂ CH ₂ CH (CH ₃ ) O-) ₁₂ -H

Specific examples of the diisocyanate compound represented by the general formula (viii) include the following compounds.
That is, 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, Aromatic diisocyanate compounds such as 1,5-naphthalene diisocyanate and 3,3′-dimethylbiphenyl-4,4′-diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate and dimer diisocyanate Compound, isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) -diisocyanate, 1 An aliphatic diisocyanate compound such as 1,3- (isocyanatomethyl) cyclohexane; a diisocyanate compound which is a reaction product of a diol and diisocyanate such as an adduct of 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate, and the like. Can be mentioned.

  The molar ratio of the diisocyanate and the diol compound used for the synthesis of the polymer compound (b1-2) is preferably 0.8: 1 to 1.2-1, and when an isocyanate group remains at the polymer terminal, alcohols or By treating with amines or the like, it is finally synthesized in a form in which no isocyanate group remains.

As the component (B1), one type may be used alone from the above polymer compounds (b1-1) and (b1-2), or two or more types may be used in combination.
The content of the repeating unit having a carboxyl group contained in the component (B1) is 2 mol% or more based on the total amount of each monomer of the component (B1), preferably 2 to 70 mol%. Yes, more preferably in the range of 5 to 60 mol%.
The preferred weight average molecular weight of the component (B1) is preferably 3000 to 300,000, more preferably 6,000 to 100,000.

  Furthermore, the preferable addition amount of the component (B1) is in the range of 0.005 to 80% by mass, preferably in the range of 0.01 to 50% by mass, based on the total solid content mass of the image recording layer. Preferably it is the range of 1-20 mass%.

[Additive]
In forming the image recording layer, in addition to the above components, various additives can be further added as necessary as long as the effects of the present invention are not impaired.
-Solubility-inhibiting compounds-
The lithographic printing plate precursor can contain various inhibitors in the image recording layer for the purpose of enhancing its inhibition (solubility inhibition).
Although it does not specifically limit as this inhibitor, A quaternary ammonium salt, a polyethyleneglycol type compound, etc. are mentioned.

Although it does not specifically limit as a quaternary ammonium salt, A tetraalkyl ammonium salt, a trialkyl aryl ammonium salt, a dialkyl diaryl ammonium salt, an alkyl triaryl ammonium salt, a tetraaryl ammonium salt, a cyclic ammonium salt, and a bicyclic ammonium salt are mentioned. .
Specifically, tetrabutylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide, tetraoctylammonium bromide, tetralaurylammonium bromide, tetraphenylammonium bromide, tetranaphthylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide , Tetrastearyl ammonium bromide, lauryl trimethyl ammonium bromide, stearyl trimethyl ammonium bromide, behenyl trimethyl ammonium bromide, lauryl triethyl ammonium bromide, phenyl trimethyl ammonium bromide, 3-trifluoromethylphenyl trimethyl ammonium bromide, benzyl trimethyl ammonium bromide De, dibenzyl dimethyl ammonium bromide, distearyl dimethyl ammonium bromide, tristearyl methyl ammonium bromide, benzyl triethyl ammonium bromide, hydroxyphenyl trimethyl ammonium bromide, N- methyl pyridinium bromide, and the like. In particular, quaternary ammonium salts described in Japanese Patent Application Nos. 2001-226297, 2001-370059, and 2001-398047 are preferable.

  The addition amount of the quaternary ammonium salt is preferably 0.1 to 50% by mass, more preferably 1 to 30% by mass, based on the total solid content of the image recording layer. The range of the content is appropriate in that the solubility inhibiting effect is sufficiently exhibited and the film forming property of the binder is not deteriorated.

  Although it does not specifically limit as a polyethyleneglycol type compound, The thing of the following structure is mentioned.

^{R 1 - {- O- (R} 3 -O-) m-R 2} n
(R ¹ is a polyhydric alcohol residue or polyhydric phenol residue, R ² is a hydrogen atom, an alkyl group, alkenyl group, alkynyl group, alkyloyl group, aryl which may have a substituent of 1 to 25 carbon atoms, aryl Group or aryloyl group, R ³ represents an alkylene residue which may have a substituent, m is an average of 10 or more, and n is an integer of 1 to 4.

  Examples of polyethylene glycol compounds having the above structure include polyethylene glycols, polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers, polyethylene glycol alkyl aryl ethers. , Polypropylene glycol alkyl aryl ethers, polyethylene glycol glycerin esters, polypropylene glycol glycerin esters, polyethylene sorbitol esters, polypropylene glycol sorbitol esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, polyethylene glycolated ethylene Diamines, polypropylene glycolated ethylenediamines, polyethylene glycolated diethylenetriamine, and polypropylene glycol diethylenetriamines.

  Specific examples thereof include polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 10000, polyethylene glycol 20000, polyethylene glycol 5000, polyethylene glycol 100000, polyethylene glycol 200000, polyethylene glycol 500000, polypropylene glycol 1500, polypropylene glycol. 3000, polypropylene glycol 4000, polyethylene glycol methyl ether, polyethylene glycol ethyl ether, polyethylene glycol phenyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol diphenyl ether Polyethylene glycol lauryl ether, polyethylene glycol dilauryl ether, polyethylene glycol nonyl ether, polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol distearyl ether, polyethylene glycol behenyl ether, polyethylene glycol dibehenyl ether, polypropylene glycol methyl ether, polypropylene glycol Ethyl ether, polypropylene glycol phenyl ether, polypropylene glycol dimethyl ether, polypropylene glycol diethyl ether, polypropylene glycol diphenyl ether, polypropylene glycol lauryl ether, polypropylene glycol dilauryl ether, polyethylene glycol Propylene glycol nonyl ether, polyethylene glycol acetyl ester, polyethylene glycol diacetyl ester, polyethylene glycol benzoate, polyethylene glycol lauryl ester, polyethylene glycol dilauryl ester, polyethylene glycol nonyl ester, polyethylene glycol cetylate, polyethylene glycol stearoyl ester, polyethylene Glycol distearoyl ester, polyethylene glycol behenate ester, polyethylene glycol dibehenate ester, polypropylene glycol acetyl ester, polypropylene glycol diacetyl ester, polypropylene glycol benzoate ester, polypropylene glycol dibenzoate ester, Ripropylene glycol laurate, polypropylene glycol dilaurate, polypropylene glycol nonyl ester, polyethylene glycol glycerol ether, polypropylene glycol glycerol ether, polyethylene glycol sorbitol ether, polypropylene glycol sorbitol ether, polyethylene glycolated ethylenediamine, polypropylene glycolated ethylenediamine, Examples thereof include polyethylene glycolized diethylenetriamine, polypropylene glycolated diethylenetriamine, and polyethylene glycolated pentamethylenehexamine.

  The addition amount of the polyethylene glycol compound is 0.1 to 50% by mass in terms of solid content with respect to the total solid content of the image recording layer from the viewpoint of exhibiting sufficient solubility inhibiting effect and maintaining good image formability. It is suitable that it is 1-30 mass%.

Further, when the above-described measures for improving the inhibition (solubility inhibition) are performed, the sensitivity is lowered. In this case, it is effective to add a lactone compound. This lactone compound is considered to be that when the developer penetrates into the exposed area, the developer and the lactone compound react to generate a new carboxylic acid compound, contributing to dissolution of the exposed area and improving sensitivity.
Although it does not specifically limit as a lactone compound, The compound represented by the following general formula (LI) and general formula (L-II) is mentioned.

In general formula (LI) and general formula (L-II), X ¹ , X ² , X ³ and X ⁴ are ring constituent atoms or atomic groups, which may be the same or different, and are independent of each other. And may have a substituent, and at least one of X ¹ , X ² and X ^{3 in} the general formula (LI) and X ¹ , X ² , X ³ and X in the general formula (L-II) ^At least one of ⁴ has an electron-withdrawing substituent or a substituent substituted with an electron-withdrawing group.
The constituent atoms or atomic groups of the ring represented by X ¹ , X ² , X ³ and X ⁴ are nonmetallic atoms having two single bonds for forming a ring or atomic groups containing the nonmetallic atoms.
A preferred nonmetallic atom or nonmetallic atomic group is an atom or atomic group selected from a methylene group, a sulfinyl group, a carbonyl group, a thiocarbonyl group, a sulfonyl group, a sulfur atom, an oxygen atom, and a selenium atom, and more preferably, It is an atomic group selected from a methylene group, a carbonyl group and a sulfonyl group.

At least one of X ¹ , X ² and X ^{3 in} the general formula (LI) or at least one of X ¹ , X ² , X ³ and X ^{4 in} the general formula (L-II) is an electron withdrawing group Have In this specification, the electron-withdrawing substituent refers to a group in which Hammett's substituent constant σ _p takes a positive value. Regarding the Hammett's substituent constant, Journal of Medicinal Chemistry, 1973, Vol. 16, No. 11, 1207-1216, etc. can be referred to. Examples of electron-withdrawing groups in which Hammett's substituent constant σ _p takes a positive valence include halogen atoms (fluorine atoms (σ _p value: 0.06), chlorine atoms (σ _p value: 0.23), bromine atoms) (Σ _p value: 0.23), iodine atom (σ _p value: 0.18)), trihaloalkyl group (tribromomethyl (σ _p value: 0.29)), trichloromethyl (σ _p value: 0.33) ), Trifluoromethyl (σ _p value: 0.54)), cyano group (σ _p value: 0.66), nitro group (σ _p value: 0.78), aliphatic / aryl or heterocyclic sulfonyl group ( For example, methanesulfonyl (σ _p value: 0.72)), aliphatic / aryl or heterocyclic acyl group (for example, acetyl (σ _p value: 0.50), benzoyl (σ _p value: 0.43)), an alkynyl group (e.g., C≡CH (sigma _p value: 0.23)), aliphatic-aryl Sik Heterocyclic oxycarbonyl group (e.g., methoxycarbonyl (sigma _p value: 0.45), phenoxycarbonyl (sigma _p value: 0.44)), carbamoyl group (sigma _p value: 0.36), a sulfamoyl group (sigma _p Value: 0.57), sulfoxide groups, heterocyclic groups, oxo groups, phosphoryl groups and the like.

Preferred electron withdrawing groups are amide groups, azo groups, nitro groups, fluoroalkyl groups having 1 to 5 carbon atoms, nitrile groups, alkoxycarbonyl groups having 1 to 5 carbon atoms, acyl groups having 1 to 5 carbon atoms, and carbon numbers. An alkylsulfonyl group having 1 to 9 carbon atoms, an arylsulfonyl group having 6 to 9 carbon atoms, an alkylsulfinyl group having 1 to 9 carbon atoms, an arylsulfinyl group having 6 to 9 carbon atoms, an arylcarbonyl group having 6 to 9 carbon atoms, and thiocarbonyl A group selected from a group, a fluorine-containing alkyl group having 1 to 9 carbon atoms, a fluorine-containing aryl group having 6 to 9 carbon atoms, a fluorine-containing allyl group having 3 to 9 carbon atoms, an oxo group, and a halogen element.
More preferably, a nitro group, a fluoroalkyl group having 1 to 5 carbon atoms, a nitrile group, an alkoxycarbonyl group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, an arylsulfonyl group having 6 to 9 carbon atoms, carbon It is a group selected from an arylcarbonyl group of formulas 9 to 9, an oxo group and a halogen element.
Specific examples of the compounds represented by formulas (LI) and (L-II) are shown below, but the present invention is not limited to these compounds.

The addition amount of the compounds represented by the general formula (LI) and the general formula (L-II) is preferably 0.1 to 50% by mass in terms of the solid content with respect to the total solid content of the image recording layer. 1-30 mass% is more preferable. In addition, since this compound reacts with a developing solution, it is desirable to contact a developing solution selectively.
These lactone compounds may be used alone or in combination. Two or more compounds of the general formula (LI) or two or more compounds of the general formula (L-II) may be used in an arbitrary ratio within the above range.

  In addition, a substance that is thermally decomposable, such as an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, and that substantially reduces the solubility of the alkaline water-soluble polymer compound without being decomposed. Use in combination is preferable in terms of improving the dissolution inhibition of the image area in the developer. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts.

Suitable onium salts for use in the present invention include, for example, SI Schlesinger, Photogr. Sci. Eng., 18, 387 (1974), TS Balet al, Polymer, 21, 423 (1980), No. 158230, diazonium salt, U.S. Pat.Nos. 4,069,055, 4,069,056, ammonium salt described in JP-A-3-140140, DC Necker et al, Macromolecules, 17, 2468 (1984), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055 and 4,069,056, JVCrivello et al, Macromorecules, 10 (6), 1307 ( 1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Pat.Nos. 339,049, 410,201, JP-A-2-150848, JP-A-2-96514 Iodonium salts described, JVCrivello et al, Polymer J. 17, 73 (1985), JV Crivelloet al. J. Org. Chem., 43, 3055 (1978), WR Watt et al, J. Polymer Sci., Polymer Chem .Ed., 22, 17 89 (1984), JV Crivello et al, Polymer Bull., 14, 279 (1985), JV Crivello et al, Macromorecules, 14 (5), 1141 (1981), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Patents 4,933,377, 3,902,114, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent Nos. 2,904,626, 3,604,580, 3,604,581, sulfonium salts, JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988). And the arsonium salts described.
Of the onium salts, diazonium salts are particularly preferred. Particularly suitable diazonium salts include those described in JP-A-5-158230.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the sensitive material system by both the effect of losing the inhibition of dissolution of the binder by thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. Although compounds described in pages 339 to 352 of “Light-Sensitive Systems” by Korser can be used, they are particularly reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulfonic acid esters or sulfonic acid amides of quinonediazides are preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters, benzoquinone- (1,2-diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5 sulfonic acid chloride and phenol-formaldehyde resins described in US Pat. Nos. 3,046,120 and 3,188,210 Esters are also preferably used.

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, No. 41-11222, No. 45-9610, No. 49-17481, U.S. Pat.No. 2,797,213, No. 3,454,400, No. 3,544,323, No. 3,573,917, No. 3,674,495, No. 3,785,825 And British Patents 1,227,602, 1,251,345, 1,267,005, 1,329,888, 1,330,932, German Patent 854,890, and the like.

The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content in the image recording layer. These compounds can be used alone, but may be used as a mixture of several kinds.
Further, an alkali-soluble resin at least partially esterified as described in JP-A-11-288089 may be included.

  Further, for the purpose of enhancing the dissolution inhibiting property on the surface of the image recording layer and enhancing the resistance to scratches on the surface, it is possible to improve the resistance against scratches on the surface as described in JP-A No. 2000-187318. It is preferable to use a polymer having a polymerization component of a (meth) acrylate monomer having 2 or 3 fluoroalkyl groups. The addition amount is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total solid content in the image recording layer.

-Development accelerator-
For the purpose of further improving sensitivity, acid anhydrides, phenols and organic acids can be used in combination.
As the acid anhydrides, cyclic acid anhydrides are preferable, and specific examples of the cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride described in US Pat. No. 4,115,128, 3, 6-Endoxy-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of the non-cyclic acid anhydride include acetic anhydride.
Examples of phenols include bisphenol A, 2,2′-bishydroxysulfone, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4- Hydroxybenzophenone, 4,4 ', 4 "-trihydroxytriphenylmethane, 4,4', 3", 4 "-tetrahydroxy-3,5,3 ', 5'-tetramethyltriphenylmethane .

Further, examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters, carboxylic acids and the like described in JP-A-60-88942 and JP-A-2-96755. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, Examples include adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like. .
The proportion of the acid anhydride, phenols and organic acids in the image recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10%. % By mass.

-Surfactant-
In the image recording layer, as described in Japanese Patent Application Laid-Open Nos. 62-251740 and 3-208514, in order to improve the coating property and to expand the stability of the processing with respect to the development conditions. Nonionic surfactants, amphoteric surfactants as described in JP-A-59-121044, JP-A-4-13149, siloxane-based compounds as described in EP950517, JP A fluorine-containing monomer copolymer as described in JP-A-62-170950, JP-A-11-288093, and Japanese Patent Application No. 2001-247351 can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of amphoteric activators include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and amphoteric surfactant in the total solid content in the image forming layer is preferably from 0.01 to 15% by mass, more preferably from 0.1 to 5% by mass, and even more preferably 0. 0.05 to 0.5 mass%.

-Bake-out agent / colorant-
In the image recording layer, a print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
A representative example of the printing-out agent is a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644, and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (above Orient Chemical Industry) Co., Ltd.), Victoria Pure Blue, Crystal Violet Lactone, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. it can. The dyes described in JP-A-62-293247 are particularly preferred.
These dyes can be added in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content in the image recording layer.

-Plasticizer-
Further, a plasticizer is added to the image recording layer as needed to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

-Wax agent-
In the image recording layer of the lithographic printing plate precursor, for the purpose of imparting scratch resistance, a compound that lowers the static friction coefficient of the surface can also be added. Specifically, esters of long chain alkyl carboxylic acids as used in US Pat. No. 6,117,913, Japanese Patent Application No. 2001-261627, Japanese Patent Application No. 2002-032904, Japanese Patent Application No. 2002-165584 And the like. The amount added is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass in the total solid content forming the layer.

A lithographic printing plate precursor can usually be produced by dissolving a heat-sensitive composition containing the above-described components in a solvent and coating the solution on a suitable support.
[Coating solvent]
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, water, etc. However, the present invention is not limited to this. These solvents are used alone or in combination.
When selecting the coating solvent, the coating solvent for the upper recording layer is used in order to prevent compatibility at the interface between the two layers of the upper recording layer and the lower recording layer when they are provided adjacent to each other. Is preferably selected so as not to substantially dissolve the lower recording layer. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
When using an acid anhydride, the water in the coating solution is preferably 0.5% or less.

[Amount of application]
Further, the coating amount (solid content) of the heat-sensitive composition varies depending on the application, but it can be provided at a coating amount of 0.3 to 3.0 g / m ² from the viewpoint of film properties and printing durability. Preferably it is 0.5-2.5 g / m < ² >, More preferably, it is 0.8-1.6 g / m < ² >.

[Multilayer structure]
The lithographic printing plate precursor used in the present invention has an image recording layer containing the above-described components provided on a support, but these image recording layers may have a multilayer structure of at least two layers. Good (for the sake of convenience, the case of two layers consisting of an upper layer and a lower layer will be described below).
In this case, the alkali-soluble resin constituting the upper layer and the lower layer can be the alkali-soluble resin described above, but the upper layer has a lower solubility in alkali than the lower layer. Is preferred.
The infrared absorbing dye may be an infrared absorbing dye different in each layer, or an infrared absorbing dye composed of a plurality of compounds may be used in each layer. The amount to be contained is 0.01 to 50% by mass, preferably 0.1 to 50% by mass, and particularly preferably 0.1% to 50% by mass, based on the total solid content of the layer to be added, as described above, when used in any layer. It can add in the ratio of 0.1-30 mass%. When adding to a several layer, it is preferable to add so that the total of addition amount may become the said range.

In the state of being thermally decomposable and not thermally decomposable, the substance that substantially lowers the solubility of the alkali-soluble resin may be partially decomposed over time, so when the image recording layer has a multilayer structure, Although it is effective to contain it in the lower layer, it may be any layer or both layers. The amount to be contained is as described above. When adding to a several layer, it is preferable to add so that the total of addition amount may become the said range.
In the case of a multilayer structure, the lactone compound is effective to be contained in the upper layer, but it may be any layer or both layers.

[Support]
Examples of the hydrophilic support used in the lithographic printing plate precursor include a dimensionally stable plate having necessary strength and durability, such as paper, plastic (for example, polyethylene, polypropylene, polystyrene). Etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate) , Polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper laminated with a metal as described above, or vapor-deposited paper, or a plastic film.

  As the support, a polyester film or an aluminum plate is preferable. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass.

  A particularly suitable aluminum is pure aluminum, but completely pure aluminum is difficult to manufacture in terms of refining technology, and may contain slightly foreign elements. Thus, the composition of the aluminum plate is not specified, and an aluminum plate made of a publicly known material can be used as appropriate. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.
The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. The amount of the anodized film is preferably 1.0 g / m ² or more in terms of printing durability. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. Examples of the hydrophilization treatment include alkali metal silicates as disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. (For example, sodium silicate aqueous solution) method. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

The lithographic printing plate precursor used in the present invention has at least the above-mentioned image recording layer provided on a support, and an undercoat layer may be provided between the support and the image recording layer as necessary. it can.
Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

  Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, —OR ^14. , -COOR ¹⁵ , -CONHR ¹⁶ , -COR ¹⁷ or -CN, or R ¹² and R ¹³ may be bonded to form a ring, and R ^{14 to} R ¹⁷ are each independently an alkyl group or Represents an aryl group, X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl. Represents a group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

This undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, then washed with water or the like and dried to provide an undercoat layer. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid.
From the viewpoint of printing durability, the coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² .

The lithographic printing plate precursor prepared as described above is imagewise exposed, and then subjected to development using the alkali developing solution detailed above.
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 present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.

  If the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming has an unnecessary image area, the unnecessary image area is erased. . Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The lithographic printing plate obtained by the plate making method of the present invention as described above can be subjected to a printing process after applying a desensitized gum if desired. If it is desired to burn, a burning process is performed. In the case of burning a lithographic printing plate, before burning, the preparations described in JP-B-61-2518, JP-A-55-28062, JP-A-1-31859, and JP-A-61-159655 are prepared. It is preferable to treat with a surface liquid.
As the method, it is possible to apply a lithographic printing plate with a sponge or absorbent cotton soaked with the surface-adjusting liquid, or immerse the printing plate in a vat filled with the surface-adjusting liquid, or apply an automatic coater. Application by, for example, is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably from 0.03 to 0.8 g / m ² (dry weight). The lithographic printing plate coated with the surface-adjusting liquid is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). . In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.
The lithographic printing plate subjected to burning treatment can be subjected to conventional treatments such as washing with water and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such treatment is applied to an offset printing machine and used for printing a large number of sheets.

  Hereinafter, the present invention will be described with reference to illustrated embodiments. FIG. 1 is a configuration diagram of a first embodiment of an automatic developing apparatus for carrying out a developer replenishing method according to the present invention. As shown in FIG. 1, this automatic developing device 2 includes a developing unit for developing a photosensitive lithographic printing plate (hereinafter referred to as “PS plate”) 4 with a developer containing an electrolyte and a development inhibitor. 6, a post-processing section 8 for washing away the developer adhering to the PS plate 4 after development and applying the gum solution, and a drying unit 10 for drying the PS plate after application of the gum solution.

  In the case of processing a PS plate that needs to be heated before the development processing, a preheating unit (not shown in FIG. 1) can be provided. The preheating unit is installed upstream of the developing unit 6 in the transport direction, and has a function of maintaining the specified PS plate surface temperature for a specified time while transporting the PS plate. The PS plate inserted in the preheating unit is automatically conveyed to the next process while being heated. Furthermore, it is possible to provide a pre-water washing section (not shown in FIG. 1). The pre-washing unit is installed on the upstream side in the transport direction of the developing unit 6 and on the downstream side in the transport direction of the pre-heating unit, and has a function of cleaning and cooling the surface of the PS plate with washing water while transporting the PS plate. The PS plate inserted in the pre-water washing unit is automatically conveyed to the developing unit 6 which is the next process.

  An insertion port 14 is formed in the side plate 12 of the automatic developing device 2, and the PS plate 4 inserted from the insertion port 14 is conveyed to the developing unit 6 by the conveyance roller 16. The insertion port 14 is provided with a rubber blade 18, and the insertion port 14 is closed by the rubber blade 18 when the PS plate 4 is not inserted.

  In the developing tank 20 of the developing unit 6, a conveyance roller 22, a brush roller 24, and a squeeze roller 26 are sequentially provided from the upstream side in the conveyance direction, and a backup roller 28 is provided at an appropriate position therebetween. The PS plate 4 is developed by being immersed in the developer while being conveyed by the conveying roller 22.

  The post-processing unit 8 connected to the developing unit 6 includes a water washing unit 8a and a finisher unit 8b. The washing unit 8 a is provided with rollers 30 a ′ and 30 a for conveying the PS plate 4 and jet members 34 a for spraying the washing solution in the washing tanks 32 a and 32 a onto the PS plate 4. And the flush water supply pump 78a which supplies flush water to the flush tank 32a is provided. Each of the finisher sections 8b is provided with a roller 30b for conveying the PS plate 4 and an injection member 34b for spraying the finisher liquid in the finisher tanks 32b and 32b to the PS plate 4, and supplying gum liquid to the finisher tank 32b. A liquid supply pump 77 and a gum liquid diluent supply pump 78b for supplying the gum liquid diluent are provided. Then, the PS plate 4 after the development processing is washed with water by spraying a washing solution by the discharge member 34a while being conveyed by the conveyance roller 30a. Further, the PS plate 4 is applied by spraying the finisher liquid by the discharge member 34b while being conveyed by the conveyance roller 30b.

  At this time, the washing tank 32a is replenished with the dilution liquid 57 in the replenishment dilution liquid tank 57 by the washing water supply pump 78a, and the finisher tank 32b is replenished with the gum solution in the gum liquid tank 56 by the pump 77. The dilution liquid 57 in the dilution liquid storage tank 53 is replenished by a replenishment dilution liquid supply pump 78b. Here, the replenishment ratio of the gum solution and the diluent is, for example, 1: 1. Along with the replenishment, the washing liquid overflowed from the washing tank 32a and the gum waste liquid overflowed from the finisher tank 32b are collected in the waste liquid tank 54 in the same manner as the development waste liquid.

  Further, it is also effective to provide the washing unit 8a with a washing brush roller (not shown in FIG. 1). The washing brush roller is installed on the upper surface or upper and lower surfaces of the PS plate 4 between the spray member 34a and the PS plate 4, and rubs and rinses the surface of the PS plate 4 being conveyed while rotating.

  On the other hand, a structure in which the water washing portion 8a is the first finisher portion 8a and the finisher portion 8b is the second finisher portion 8b is also effective. The first finisher portion 8a and the second finisher portion 8b are provided with transport rollers 30a and 30b for transporting the PS plate 4, and jet members 34a and 34b for spraying the gum solution in the finisher tanks 32a and 32b to the PS plate 4, The PS plate 4 after the development processing is applied by spraying a gum solution by the spray members 34a and 34b while being transported by the transport rollers 30a and 30b. At this time, the gum solution in the finisher tank 32b of the second finisher section 8b on the downstream side is supplied by overflowing into the finisher tank 32a of the first finisher section 8a on the upstream side. Instead of this, it may be similarly supplied by a pump or the like. In this case, the flush water supply pump 78a is not used.

  At this time, the gum liquid in the gum liquid tank 56 is replenished to the second finisher tank 32 b by the pump 77 and the dilution liquid 57 in the replenishment dilution liquid storage tank 53 is replenished by the replenishment dilution liquid supply pump 78. Here, the replenishment ratio of the gum solution and the diluent is, for example, 1: 1. With this replenishment, the gum waste liquid overflowed from the first finisher tank 32a is collected in the waste liquid tank 54 in the same manner as the development waste liquid.

  The drying unit 10 connected to the finisher unit 8 is provided with a guide roller 36 and a pair of skewer rollers 38 in order from the upstream side in the transport direction. The drying unit 10 is provided with drying means such as hot air supply means and heat generation means (not shown). The drying unit 10 is provided with a discharge port 40, and the PS plate 4 dried by the drying means is discharged from the discharge port 40. In addition, a shutter 44 is provided in a path between the drying unit 10 and the finisher unit 8, and the path 46 is closed by the shutter 44 when the PS plate 4 does not pass through the path 46.

  The developing tank 20 is provided with a box-shaped shielding lid 60 integrally with the tank wall. The bottom wall of the shielding lid 60 is continuously curved in an arc shape so as not to come into contact with the upper outer peripheral surfaces of the transport roller 22, the brush roller 24, and the backup roller 28, and does not interfere with the roller or the like. Since the shielding lid 60 is box-shaped, an airtight space is defined in the upper part of the developing tank 20, and the amount of air in the developing unit 6 is reduced as much as possible. Further, since the shielding lid 60 is provided, the contact area between the developer and air is reduced as much as possible.

  In the automatic developing apparatus 2 having the above-described configuration, the rubber blade 62 is provided at an appropriate place, and the developing unit 6 to the finisher unit 8b are substantially airtight with respect to the external atmosphere, so that outside air does not flow in. ing. Further, a space between the developing unit 6 and the water washing unit 8a is substantially airtight by the rubber blade 62 so that air in the water washing unit 8a does not flow into the developing unit 6. Therefore, the developing unit 6 has a hermetically sealed structure in which air flows in slightly when the PS plate 4 passes, but is substantially airtight and hardly receives air.

  Next, the developing unit 6 will be described in detail. A developing solution circulation pipe 80 is connected to the developing tank 20. In the circulation pipe 80, a developer circulation pump 71, an electrical conductivity sensor 73, and a filter (not shown) are provided. The developer circulation pump 71 sucks the developer in the developer tank 20 from the suction hole at the bottom of the developer tank 20 into the circulation pipe 80 and circulates in the circulation pipe 80, and again into the developer tank 20. Discharge. The filter filters the developer flowing in the circulation pipe 80. The conductivity sensor 73 measures the conductivity of the developer flowing in the circulation pipe 80.

  Further, the developing unit 6 includes replenishment stock solution storage tanks 55a and 55b connected to replenishment pipes 90a and 90b, respectively, and replenishment stock solution supply pumps interposed respectively in the replenishment pipes 90a and 90b. 74a, 74b, a replenishment diluent storage tank 53 connected to the replenishment piping 91, and a replenishment dilution supply pump 76 interposed in the replenishment piping 91 are provided, and these function as replenishment liquid feeding means. . Further, the developing waste liquid overflowed from the developing tank 20 is collected in the waste liquid tank 54.

  In the automatic developing apparatus 2 according to the present invention, as a development replenisher, a development replenisher having higher conductivity than the developer (referred to as the first replenisher in this embodiment) and a development inhibitor concentration from the developer. The developer replenisher can be replenished with two types of developer replenisher (which is a second replenisher in the present embodiment) with increased electrical conductivity. In the present embodiment, the first replenisher is stored in the replenishment stock solution storage tank 55a, and the second replenisher is stored in the replenishment stock solution storage tank 55b.

  More specifically, in the vicinity of the developing tank 20, development replenishment solution replenishment pipes 90 a, 90 b, and 91 obtained by diluting the development replenishment stock solution 58 with the replenishment dilution solution 57 are provided. Each of the replenishment pipes 90a and 90b of the development replenishment stock solutions 58a and 58b is connected to the replenishment stock solution storage tanks 55a and 55b at the other end (lower end in FIG. 1). Is provided. The replenishing stock solution supply pumps 74a and 74b measure the conductivity by the conductivity value sensor 73 in order to keep the developer activity constant, and compare the measured electric power (conductivity measured value) with a predetermined electric power reference value. When the measured conductivity is lower than the conductivity reference value, the development replenishing stock solutions 58a and 58b (the first replenishing solution and the second replenishing solution) are supplied from the replenishing stock solution storage tanks 55a and 55b to the developing tank 20. To do. The replenishment pipe 91 for the replenishment diluent 57 has the other end (lower end in FIG. 1) connected to the replenishment diluent storage tank 53, and a replenishment diluent supply pump 76 is provided in the pipe. The replenishment diluent supply pump 76 supplies the replenishment diluent (water) 57 from the replenishment diluent storage tank 53 to the developing tank 20. That is, the replenishment pipe 91, the replenishment diluent supply pump 76, and the replenishment diluent storage tank 53 constitute a dilution water replenishment device.

As the electrical conductivity reference value, an electrical conductivity value calculated from the processing amount of the PS plate processed in the developer can be used. When the electrical conductivity measurement value is lower than the electrical conductivity reference value, the development is performed from the developer. A developer replenisher (second replenisher) having a higher inhibitor concentration and higher electrical conductivity is replenished.
In this way, even if the concentration of the development inhibitor in the developing solution in the developing unit decreases according to the processing amount, the development inhibitor can be replenished by the amount corresponding to the reduction in the processing amount of the PS plate.

Alternatively, as the conductivity reference value, the replenishment ratio over time, which is the ratio of the replenishment amount over time calculated from the operation time and the stop time of the automatic developing device to the phase replenishment amount, and the developer replenisher replenished in the developer The conductivity value calculated from the replenisher replacement rate, which is the ratio of the above, can be used. When the measured conductivity value is lower than the conductivity reference value, the developer replenisher solution having the conductivity higher than that of the developer solution (first 1).
In this way, even if the alkali components of the developing solution in the developing unit decrease with time, these alkali components can be replenished by the reduced amount.

  The replenishment stock solution supply pumps 74a and 74b and the replenishment dilution solution supply pump 76 include a control ROM 51a or control RAM 51b and a time measurement unit 52, which are condition storage means, based on signals from the conductivity sensor 73 and the time measurement unit 52. It is controlled by a control device (control means) 50. Further, the control device 50 drives the transport roller 22, the brush roller 24, the squeeze roller 26, and the like at appropriate timing based on the signal from the plate detection sensor 27, and transports the PS plate.

  Further, the control device 50 measures the elapsed time from the previous time-based replenishment integration time and the elapsed time from the previous conductivity measurement time by the time measuring unit 52, and measures the developer conductivity by the conductivity sensor 73. Then, if necessary using the values, the control device 50 develops a replenisher (development replenisher stock solution 58a + replenisher diluent 57 or development replenisher stock solution 58b + replenishment) at a predetermined replenishment amount / replenisher dilution ratio. The diluent 57) is supplied to the developing tank 20 from the replenishment stock solution storage tanks 55a and 55b and the replenishment dilution solution storage tank 53. Further, if necessary, both the first replenisher and the second replenisher may be replenished by adjusting the ratio.

  Next, control by the control device 50 will be described. 2, 3, 4, and 5 are examples of flowcharts showing a control method by the control device 50. With these control methods, it is possible to perform replenishment with an appropriate replenishment amount even when processing conditions such as plate type, plate size, and processing frequency change.

First, a basic control process for replenishing the developer replenisher will be described with reference to FIG.
After starting of the automatic developing machine, step 11, (hereafter S11 and abbreviated), experimentally determined in advance developer activity is properly the electric conductivity of developer value conductivity reference value: set to d _T . Next, in S12, it is determined whether the elapsed time from the time of starting or the previous developer conductivity measurement has reached a predetermined time. If it has reached, the process proceeds to S13, and if not, the process proceeds to S16.
In S13, the electric conductivity of the developer is measured. Next, in S14, by comparing the measured electric conductivity of developer value d _M and the electric conductivity reference value d _T, the electric conductivity of developer value d _M is to step S15 is smaller than the electric conductivity reference value d _T, otherwise S16 Proceed to
In S15, the first replenisher is replenished to the developer with a predetermined replenisher amount, and the process proceeds to S16.
In S16, the state of the operation switch of the automatic developing machine is investigated. If the operation switch is turned on, the process returns to S12. If the operation switch is turned off, the process is terminated by stopping the apparatus.

Next, the first control process specifically showing the basic control process will be described with reference to FIG.
In this control process, the conductivity value calculated from the total processing amount of the photosensitive lithographic printing plate processed in the developer is used as the conductivity reference value.
In S21, a processing amount integrated value: I _S that is a variable used during control is initialized, that is, 0 is substituted.
In S22, the integrating the processing area I _S when the processing has been performed. Next, in S23, the electric conductivity reference value from this I _S: calculated by the calculation equation d _T. The arithmetic expression used at this time is preferably the following expression, for example.
d _T = (D _M −D _L ) × EXP (−C ₁ × I _S ) + D _L : Formula 1
(D _M , D _L , C ₁ are constants experimentally obtained in advance, EXP (x) = e ^x )

Next, in S24, it is determined whether the elapsed time from the time of starting or the previous measurement of the developer conductivity has reached a predetermined time.
In S25 electric conductivity of the developer is measured, the value assigned to a variable: d _M. In the next S26, compares the d _M and d _T, in S27 the smaller the d _M, the process proceeds to S28 larger the d _M. In S27, the second replenisher is replenished to the developer with a predetermined replenisher amount.

  In S28, the state of the operation switch of the automatic developer is investigated. If the operation switch is turned on, the process returns to S22, and if the operation switch is turned off, the process is terminated by stopping the apparatus.

Next, the second control process will be described with reference to FIG.
In this control process, the conductivity value calculated from the replenisher replacement rate which is the ratio of the developer replenisher replenished to the developer in the developer is used as the conductivity reference value.
First, in S31, it is determined whether or not the automatic processor is activated for the first time. If it is the first activation, the replenisher replacement rate: X, which is a variable used during the control, is initialized, that is, 0 is substituted. To do.
In S32, the electric conductivity reference value from X: is calculated by calculating equation d _T. The arithmetic expression used at this time is preferably the following expression.
_{d T = (1 - X)} × d M + X × d L: computing equation 2
(d _M and d _L are constants obtained experimentally in advance)

Next, in S33, it is determined whether the elapsed time from the time of starting or measuring the previous developer conductivity has reached a predetermined time. If it has elapsed, the process proceeds to S34, and if not, the process proceeds to S38.
In S34 electric conductivity of the developer is measured, the value assigned to a variable: d _M. In the next S35, compares the d _M and d _T, to S36 Smaller d _M, the process proceeds to S38 larger the d _M. In S36, the first replenisher is replenished to the developer with a predetermined replenisher amount: _VH , and in the next S37, X is updated using _VH and an arithmetic expression. At this time, it is desirable to use the following arithmetic expression.
_{X = (V T × X o} + V H) ÷ (V T + V H): computing equation 3
(X _o is the pre-update replenisher replacement ratio value, V _T is the developer capacity of the developing tank)

  In S38, the state of the operation switch of the automatic developer is checked. If the operation switch is turned on, the process returns to S32, and if the operation switch is turned off, the process is terminated by stopping the apparatus.

Next, the third control process will be described with reference to FIG.
In this control process, the replenishment ratio over time, which is the ratio of the replenishment volume over time calculated from the operation time and stop time of the photosensitive lithographic printing plate automatic developing machine to the total replenishment amount, and the development replenisher replenished to the developer The conductivity value calculated from the replenisher replacement rate, which is the ratio in the developer, is used as the conductivity reference value.
In S41, the replenishment integrated value: I _C which is a variable used during the control is initialized, that is, 0 is substituted. Further, it is determined whether or not the automatic processor is activated for the first time. If it is the first activation, the replenisher replacement rate: X and the replenishment rate with time: F, which are variables used during the control, are initialized. That is, 0 is substituted for X, and a predetermined constant: C _F is substituted for _F.

In S42, the replenishment amount with time corresponding to the stop time of the automatic processor: T _F is integrated into I _C. For example, the calculation is performed as follows.
I _C + V _F × T _F → I _C : Calculation formula 4
(V _F is a constant obtained experimentally in advance)

In S43, the elapsed time from the time of integrating the startup or previous time lapse replenishment amount, a predetermined time: determining whether reached T _K, in S44 if passed, the process proceeds to S45 when not reached .
In S44, the elapsed time: the time lapse replenishment amount required by T _K is integrated into I _C. For example, the calculation is performed as follows.
I _C + V _N × T _K → I _C : Calculation formula 5
(V _N is a constant obtained experimentally in advance)

In S45, X, the values of F and operation expression by using the electric conductivity reference value: calculating a d _T. At this time, it is desirable to use the following arithmetic expression.
d _T = (1-X) x D _M + X x ((1-F) x D _B + F x D _C )
: Calculation formula 6
(D _M , D _B , D _C are constants obtained experimentally in advance)

Next, in S46, the time elapsed from the time or the time of measuring the last electric conductivity of developer starts, predetermined time: it is determined whether or not reached T _D, in S47 if the elapsed when not reached Proceed to S52.
In S47 electric conductivity of the developer is measured, the value assigned to a variable: d _M. In the next S48, the electric conductivity of developer: d _M and the electric conductivity reference value: comparing the d _T, when d _M is small to S49, otherwise proceed to S52.

In S49, to replenish the first replenisher amount of V _H as the d _M> d _T in the developer.
In the next S50, the values of X and F are updated with the values of I _C and V _H. For example, it is appropriate to update the value using the following arithmetic expression.
(V _T × X + V _H ) ÷ (V _T + V _H ) → X: Equation 7
(V _T × X × F + I _C ) ÷ (V _T × X + V _H ) → F: Formula 8
(V _T is the volume of developer in the developer tank)
In the next S51, I _C is initialized, that is, 0 is substituted.

  In S52, the state of the operation switch of the automatic developing machine is checked. If the operation switch is turned on, the process returns to S25, and if the operation switch is turned off, the process is terminated by stopping the apparatus.

  According to the control of the above automatic developing machine, the developer replenisher having higher conductivity than the developer by using the value of the developer conductivity, even with respect to changes in the type, size and processing frequency of the photosensitive material. By developing a developer replenisher having a higher development inhibitor concentration and higher conductivity than that of the developer, it is possible to perform development with a stable and constant sensitivity. Accordingly, it is possible to minimize the variation in the developer sensitivity with respect to the change in the development processing conditions while making the developing unit of the automatic developing machine simple and inexpensive.

  Next, a second embodiment of the present invention will be described. FIG. 6 is a block diagram of an automatic developing apparatus according to the second embodiment of the present invention. As shown in FIG. 6, in the automatic developing apparatus 100 of the present embodiment, the internal processing unit is covered with an outer panel 114. Inside the outer panel 114, a developing tank 118 for developing the PS plate 112, a developing section 122 having an overflow pipe 120 for collecting the developer overflowed from the developing tank 118, and the PS plate 112 were attached. A water washing part 124 for washing the developer with water and a finisher part 126 for applying a gum solution to the PS plate 112 after washing with water and desensitizing it are disposed. The flushing section 124 is provided with a flushing tank 128, and the finisher section 126 is provided with a gum solution tank 130.

  The outer panel 114 is provided with a slit-like insertion port 202 and a discharge port 204, respectively. A reentry insertion port (sub-insertion port) 250 for inserting the PS plate 112 is provided between the developing unit 122 and the water washing unit 124 on the upper surface of the outer panel 114. The sub-insertion opening 250 serves as an insertion opening for the PS plate 112 for performing processing excluding development processing.

  A blade 252 is disposed in the sub insertion port 250. The blade 252 is in contact with the outer panel 114 whose tip is used as a guide support surface of the sub insertion port 250, and the base is fixed to the back side of the outer panel 114 via a bracket 254. For this reason, the sub insertion port 250 is closed by the blade 252.

  The drying unit (not shown) is configured to blow hot air on both sides of the PS plate 112 while drying the PS plate 112 fed from the finisher unit 126 by a plurality of rollers (not shown). Yes.

  A pair of conveying rollers 132 is disposed on the side of the developing unit 122 where the PS plate 112 is inserted into the developing tank 118, and the PS plate 112 is inserted between the pair of conveying rollers 132 from the insertion port 202. It is like that.

  A rubber blade 206 is attached in the vicinity of the downstream side of the conveying roller 132. The tip of the blade 206 is in contact with the side wall of the developing tank 118 of the developing unit 122, and the base is attached to the outer panel 114 via a bracket 256. The bracket 256 includes a fixed portion 256A and a slide portion 256B attached to the fixed portion with a thumbscrew 258, and the blade 206 is fixed to the slide portion 256B. For this reason, the blade 206 is configured such that the tip end portion can be separated from the side wall of the developing tank 118 by loosening the thumbscrew 258 and sliding the slide portion 256B relative to the fixed portion 256A.

  In addition, a plate detection sensor 208 capable of measuring the presence / absence of the PS plate 112 and the plate area of the transported plate is attached near the insertion port 202.

  The developing tank 118 has a substantially inverted mountain shape with the upper part opened and the bottom center part protruding downward. A pump 260 is provided in the developing tank 118, and the developer in the developing tank 118 is sucked out by the pump 260 and ejected from spray pipes 144 and 272 described later. Thereby, the developer stored in the developing tank 118 is circulated. During this circulation, it passes through a conductivity sensor 262 that measures the conductivity of the developer. The developing tank 118 is supplied with a replenishing stock solution from a replenishing stock solution tank 266a storing a first replenisher solution and a 266b storing a second replenisher solution via replenishing stock solution supply pumps 264a and 264b. It has become so. As will be described later, the developing tank 118 is supplied with dilution water from a washing tank 128 via a pump 286.

  The pumps 264 a and 264 b and the pump 286 are controlled by a control device 50 including a control ROM 51 a or a control RAM 51 b as a condition storage unit and a time measurement unit 52 based on signals from the conductivity sensor 262 and the time measurement unit 52. The In addition, since the effect of the control apparatus 50 is the same as that of 1st Embodiment, the description is abbreviate | omitted.

  In the developing tank 118, a guide plate 268 is disposed on the upstream side, and a number of guide rollers 134 and a rotating brush roller 270 are disposed on the downstream side. The guide roller 134 and the rotating brush roller 270 are rotatably spanned between a pair of side plates of the developing tank 118.

  A guide roller 136 having a relatively large diameter is provided above the guide plate 268, a rotating brush roller 138 and a guide roller 140 are provided above the guide roller 134, and a rotating brush roller 270 is provided below the guide roller 140. Each is arranged. In addition, a pair of squeezing rollers 142 having a function of squeezing the surface of the PS plate 112 are disposed in the center of the developing tank 118.

  The overflow pipe 120 is disposed on the most downstream side of the developing tank 118. When the level of the developer exceeds a predetermined level, the developer is guided to the waste tank 284 and discarded.

  A liquid level lid 150 is disposed on the surface of the developer in the developing tank 118. The liquid level cover 150 has a portion corresponding to the rotating brush roller 138 and the guide roller 140 adjacent thereto protruding in a substantially arc shape, and is in close contact with the developer surface in order to minimize the contact between the developer surface and air, Both ends of the liquid surface lid 150 in the transport direction of the PS plate 112 are attached to a side plate (not shown) so as to move up and down according to the increase / decrease of the developer.

  The tip of the blade 274 is in contact with the downstream end of the liquid level lid 150 in the transport direction. The blade 274 is fixed to the outer panel 114 via a bracket 276. The blade 274 partitions the liquid level of the developer exposed from the downstream end in the transport direction of the liquid level cover 150 from the upper side of the liquid level cover 150, and the blade 206 (the developing tank 118 of the developing tank 118) in the vicinity of the insertion port 202. The state in contact with the side wall) completely separates the upper portion of the liquid level cover 150 from the outside air, and can suppress evaporation of the developer.

  A pair of rollers 154 that sandwich and transport the PS plate 112 and squeeze the developer from the surface of the PS plate 112 are disposed on the most downstream side in the transport direction of the developing tank 118.

  On the other hand, the automatic developing apparatus 100 is provided with a water washing tank 128 of a water washing unit 124 on the downstream side of the developing unit 122. Two pairs of transport rollers 152 and 153 are disposed above the water washing tank 128.

  The rinsing tank 128 stores rinsing water after the developer is washed out from the PS plate 112 sent out from the developing tank 118. A spray pipe 156 is disposed on the upstream side of the transport roller 153 and on the upper side of the transport path, and a plurality of discharge ports communicating with the inside are provided on the outer periphery of the spray pipe 156. From the spray pipe 156, the washing water pumped up from the washing water tank 278 by the pump 280 is dropped onto the roller on the upper side of the conveying roller 153, and the conveying roller 153 rotates, so that the washing water quickly flows onto the surface of the PS plate 112. And the surface of the PS plate 112 is washed with water.

  The lower part of the lower roller of the transport rollers 152 and 153 is accommodated in the tray 162. Washing water is stored in the tray 162 and is pumped up by the lower roller to clean the back surface of the PS plate 112 and to prevent the upper transport rollers 152 and 153 from drying.

  Further, the washing water diffused in the width direction on the surface of the PS plate 112 falls from the both ends in the width direction of the PS plate 112 to the receiving tray 162 below, and the back surface of the PS plate 112 is washed away by the washing water pumped up from the receiving plate 162. It is configured to be processed. The flush water overflowing from the tray 162 is guided to the flush tank 128. The flush tank 128 is provided with an overflow pipe 282, which is discarded into a waste liquid tank 284 when a predetermined liquid level is exceeded.

  The washing tank 128 and the developing tank 118 are communicated with each other via a pump 286, and the washing water in the washing tank 128 is guided to the developing tank 118 by driving the pump 286, and the replenishing stock solution is supplied to the developing tank 118. It can be used as a diluting solution when supplying.

  A pair of transport rollers 178 are provided above the gum solution tank 130 of the finisher portion 126. The PS plate 112 sent out by the transport roller 153 is guided to the transport roller 178.

  In addition, spray pipes 182 and 288 are arranged on the upstream side of the conveyance roller 178 in the vertical direction of the conveyance path. From the spray pipes 182 and 288, the gum solution pumped up from the gum solution tank 290 by the pump 292 is discharged and supplied to the front and back surfaces of the PS plate 112.

  The conveyance roller 178 nips and conveys the PS plate 112 and squeezes the gum solution supplied by the spray pipe 182 to desensitize the surface of the PS plate 112. The gum solution squeezed from the surface of the PS plate 112 is collected in the gum solution tank 130. The gum solution in the gum solution tank 130 is circulated by a pump 294. The gum solution tank 130 is provided with an overflow pipe 296 so that when the gum solution exceeds a predetermined level, it is guided to the waste solution tank 284 and discarded.

  Further, the lower part of the lower conveyance roller 178 is immersed in the gum liquid stored in the gum liquid tank 130, and the lower conveyance roller 178 is connected to the gum liquid tank 130 from the gum liquid tank 130 on the back side of the PS plate 112. The coating process is performed by pumping up. As a result, the conveying roller 178 takes out the gum solution to perform the desensitization process on the back surface of the PS plate 112 and suppresses the drying of the upper conveying roller 178 so that the components of the processing liquid do not deposit on the surface of the conveying roller 178. It has become.

  The PS plate 112 that has been processed by the finisher unit 126 passes through the discharge port 204 of the casing 200 and is sent to a drying unit (not shown).

  Here, the discharge port 204 is provided with a lid 210 as a partition plate. The lid 210 is fixed to the shaft 212. The shaft 212 can be rotated by driving means (not shown) (for example, a solenoid). The rotation of the shaft 212 is performed based on the detection of the PS plate 112 by the plate detection sensor 208 provided in the vicinity of the insertion port 202. In other words, the lid 210 is substantially horizontal (after the detection of the discharge port 204) while the plate detection sensor 208 is detecting the PS plate 112 and after it is no longer detected (after the rear end is detected) until a predetermined time elapses. It is held in an open state, and the others are vertical (the discharge port 204 is closed).

  The operation of this embodiment will be described below. First, processing tanks such as the developing tank 118, the washing tank 128, and the gum solution tank 130 are covered with a casing 200 such as an upper lid 114 and a main body 108. Further, when the PS plate 112 is not developed by the automatic developing device 100, the insertion port 202 is closed because the blade 206 is in contact with the side wall of the developing tank 118. On the other hand, since the discharge plate 204 does not detect the PS plate 112 by the plate detection sensor 208, the lid 210 is in a vertical state, and the discharge port 204 is also closed. Further, the sub insertion port 250 is also closed by the blade 252, and the upper part of the liquid level cover 150 of the developing unit 122 is also closed by the blade 206. For this reason, the developing solution in the developing tank 118, the washing water in the washing unit 124, and the gum solution in the finisher unit 126 are not exposed to the outside air, and there is almost no carbon dioxide fatigue. For this reason, since it is possible to suppress a decrease in developing ability due to deterioration over time, for example, the replenishing amount of the replenishing stock solution in the developing unit 122 can be drastically reduced. In particular, since the surface of the developer in the developing tank 118 is covered with the liquid level lid 150, the effect of preventing contact between the developer and the outside air is great.

  In order to minimize the contact between the developing solution and the outside air, it is preferable to shorten the opening time of the lid 210 as much as possible. Therefore, a structure in which the PS plate 112 is open only while it passes and is closed during the other time is preferable.

  The control by the control device 50 is the same as the contents of the flowchart of the replenishing method of the developing replenisher in FIGS. 2, 3, 4 and 5 described in the first embodiment, and the description thereof is omitted here. To do.

EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples. In the examples, “%” represents “% by mass”.
[Preparation of alkaline developer / developer replenisher containing SiO2]
Various development inhibitors are added to 1 L of potassium silicate 4.0% aqueous solution having a mixing ratio SiO2 / K2O of 1.1 of silicon oxide SiO2 and potassium oxide K2O as shown in Table 1 below, and the alkaline developers (1) to ( 5) was produced. Further, various development inhibitors are added to 1 L of a 6.0% aqueous solution of potassium silicate having a mixing ratio SiO2 / K2O of 1.1 of silicon oxide SiO2 and potassium oxide K2O as shown in Table 1 below, and the alkali development replenisher (1) of the present invention a · b to (5) a · b were prepared.
[Adjustment of non-reducing sugar-containing alkaline developer / developer replenisher]
Various development inhibitors are added to 1 L of a 5.0% aqueous solution of D-sorbate potassium salt composed of D-solvate / potassium oxide K2O in which non-reducing sugar and a base are combined, and the alkaline developer of the present invention ( 6) to (10) were prepared. In addition, various development inhibitors are added to 1 L of a 6.5% aqueous solution of D-sorbate potassium salt composed of D-solvate / potassium oxide K2O, which is a combination of a non-reducing sugar and a base, as shown in Table 2 below. Replenishers (6) a · b to (10) a · b were prepared.

Using a heat-sensitive positive lithographic printing plate, development processing was performed with the various alkali processing solutions described above.
[Production of heat-sensitive positive lithographic printing plate]
A 0.3 mm thick aluminum plate (material 1050) was washed with trichlorethylene and degreased, and then a nylon brush and 400 mesh pumice-water suspension were used to make the surface grainy and washed thoroughly with water. After washing, this aluminum plate was etched by immersing it in a 25% aqueous sodium hydroxide solution at 45 ° C. for 9 seconds, washed with water, 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, the aluminum plate was provided with an anodized film of 3 g / m ² with a direct current of 15 A / dm ² using 7% sulfuric acid as an electrolytic solution, and then washed and dried. This was treated with a 2.5% aqueous solution of sodium silicate at 30 ° C. for 10 seconds, the following undercoat layer coating solution was applied, and dried at 80 ° C. for 15 seconds to obtain a support. The dry coating amount of the undercoat layer after drying was 15 mg / m ² .

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

Synthesis Example 1 (Synthesis of alkali-soluble polymer compound (copolymer) having a carboxyl group)
In a 20 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel, 6.39 g (0.045 mol) of n-propyl methacrylate, 1.29 g (0.015 mol) of methacrylic acid and 1-methoxy-2- 20 g of propanol was added, and the mixture was stirred while being heated to 65 ° C. with a hot water bath. To this mixture, 0.15 g of “V-601” (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 2 hours under a nitrogen stream while maintaining at 70 ° C. To this reaction mixture, 6.39 g (0.045 mol) of n-propyl methacrylate, 1.29 g (0.015 mol) of methacrylic acid, 20 g of 1-methoxy-2-propanol and 0.15 g of “V-601” The mixture was added dropwise via a dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 90 ° C. for 2 hours. After completion of the reaction, 40 g of methanol is added to the mixture, the mixture is cooled, and the resulting mixture is poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate is removed by filtration and dried. Gave 15 g of a white solid. When the weight average molecular weight (polystyrene standard) of this copolymer was measured by gel permeation chromatography, it was 53,000.

Synthesis Example 2 (Synthesis of alkali-soluble polymer compound having a carboxyl group (copolymer))
By the same operation as in Synthesis Example 1, a copolymer was synthesized using ethyl methacrylate / isobutyl methacrylate / methacrylic acid (mol%: 35/35/30). The weight average molecular weight (polystyrene standard) was measured and found to be 50,000.

Synthesis Example 3 (Synthesis of polyurethane resin having a carboxyl group)
Into a 500 ml three-necked round bottom flask equipped with a condenser and a stirrer was added 14.6 g (0.109 mol) of 2,2-bis (hydroxymethyl) propionic acid and 13.3 g (0.0686 mol) of tetraethylene glycol. ) And 2.05 g (0.0228 mol) of 1,4-butanediol were added and dissolved in 118 g of N, N-dimethylacetamide. To this, 30.8 g (0.123 mol) of 4,4′-diphenylmethane diisocyanate, 13.8 g (0.0819 mol) of hexamethylene diisocyanate and 0.1 g of di-n-butyltin dilaurate as a catalyst were added and stirred. Under heating at 90 ° C. for 7 hours. N, N-dimethylacetamide (100 ml), methanol (50 ml) and acetic acid (50 ml) were added to the reaction solution, and the mixture was stirred and then added to 4 liters of water with stirring to precipitate a white polymer. The polymer was separated by filtration, washed with water, and dried under reduced pressure to obtain 60 g of polymer.
When the molecular weight was measured by gel permeation chromatography (GPC), the weight average (polystyrene standard) was 70,000. The carboxyl group content measured by titration was 1.43 meq / g.

Synthesis Example 4 (Synthesis of polyurethane resin having a carboxyl group)
The following diisocyanate compounds (mol%)

And the following diol compounds (mol%)

  Was used in the same manner as in Synthesis Example 3 to synthesize a copolymer. The acid content of the obtained copolymer by titration was 1.72 meq / g, and the weight average molecular weight (polystyrene standard) was 80,000.

Synthesis example 5
A 500 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel is charged with 31.0 g (0.36 mol) of methacrylic acid, 39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile and cooled in an ice-water bath The mixture was stirred while. To this mixture, 36.4 g (0.36 mol) of triethylamine was dropped with a dropping funnel over about 1 hour. After completion of the dropwise addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes. To this reaction mixture, 51.7 g (0.30 mol) of p-aminobenzenesulfonamide was added, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After completion of the reaction, this mixture was added to 1 liter of water with stirring, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to take out a precipitate, which was slurried with 500 ml of water, and then the slurry was filtered, and the resulting solid was dried to give white N- (p-aminosulfonylphenyl) methacrylamide. A solid was obtained (yield 46.9 g). Next, 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide (0.0192 mol) was added to a 20 ml three-necked flask equipped with a stirrer, condenser and dropping funnel. Then, 2.94 g (0.0258 mol) of ethyl methacrylate, 0.80 g (0.015 mol) of acrylonitrile and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of “V-65” (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 2 hours under a nitrogen stream while being kept at 65 ° C. A further mixture of 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.94 g of ethyl methacrylate, 0.80 g of acrylonitrile, N, N-dimethylacetamide and 0.15 g of “V-65” was added to this reaction mixture. It dropped by the dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, 40 g of methanol is added to the mixture, the mixture is cooled, and the resulting mixture is poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate is removed by filtration and dried. Gave 15 g of a white solid. It was 53,000 when the weight average molecular weight (polystyrene standard) of this specific copolymer was measured by the gel permeation chromatography. The following image recording layer coating solution was applied onto the obtained support and dried at 150 ° C. for 30 seconds to obtain a dry lithographic printing plate precursor A having a dry coating amount of 1.8 g / m ² .

<Coating liquid for image recording layer>
Copolymer of Synthesis Example 2 0.050g
Copolymer of Synthesis Example 4 0.050 g
0.4 g of copolymer of Synthesis Example 5
0.6 g of m, p-cresol novolak
(M / p ratio = 6/4, weight average molecular weight 8000, containing 0.5% of unreacted cresol)
Cyanine dye A 0.1g
Phthalic anhydride 0.05g
0.002 g of p-toluenesulfonic acid
Ethyl violet 0.02g
(Counterion: 6-hydroxy-β-naphthalenesulfonic acid)
0.01 g of esterified product of naphthoquinone 1,2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin
Fluorosurfactant 0.05g
(Product name: Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
Methyl ethyl ketone 8g
1-methoxy-2-propanol 4g

The following image recording layer coating solution 1 was applied to an aluminum support treated in the same manner as described above with a wire bar so that the coating amount was 0.85 g / m ^2, and then PERFECT manufactured by TABAI. Wind control was set to 7 with OVER PH200 and dried at 140 ° C for 50 seconds. Furthermore, after coating the image recording layer coating solution 2 with a wire bar so that the coating amount becomes 0.22 g / m ² , WindControl is set to 7 on the PERFECT OVER PH200 manufactured by TABAI, and the temperature is set to 120 ° C. The plate was dried in 60 seconds to obtain a lithographic printing plate precursor B having a two-layer image forming layer.

<Coating liquid 1 for image recording layer>
Copolymer of Synthesis Example 2 0.050g
Copolymer of Synthesis Example 4 0.050 g
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate (36/34/30 weight average molecular weight 50000) 1.896 g
Cresol novolak (m / p = 6/4 weight average molecular weight 4500, residual monomer 0.8wt%) 0.237g
Cyanine dye A 0.109g
4,4'-Bishydroxyphenylsulfone 0.063g
Tetrahydrophthalic anhydride 0.190g
p-Toluenesulfonic acid 0.008g
0.05 g of ethyl violet counter ion changed to 6-hydroxynaphthalene sulfone
Fluorosurfactant (F176, manufactured by Dainippon Ink & Chemicals, Inc.) 0.035g
Methyl ethyl ketone 26.6g
13.6 g of 1-methoxy-2-propanol
γ-butyrolactone 13.8 g

<Image recording layer coating solution 2>
Copolymer of Synthesis Example 2 0.050g
Copolymer of Synthesis Example 4 0.050 g
Cresol novolak (m / p = 6/4 weight average molecular weight 4500,
Residual monomer 0.8wt%) 0.237g
Cyanine dye A 0.047g
0.060 g dodecyl stearate
3-methoxy-4-diazodiphenylamine hexafluorophosphate
0.030g
Fluorosurfactant (F176 (20% solution), manufactured by Dainippon Ink & Chemicals, Inc.)
0.110 g
Fluorosurfactant (MCF312F (30% solution), manufactured by Dainippon Ink Industries, Ltd.)
0.12g
Methyl ethyl ketone 15.1g
7.7 g of 1-methoxy-2-propanol

The lithographic printing plate precursors A and B obtained above are exposed at a main scanning speed of 5 m / sec using a semiconductor laser having an output of 500 mW, a wavelength of 830 nm, and a beam diameter of 17 μm (1 / e ² ), and maintained at 25 ° C. did. For this lithographic printing plate, when the development replenisher replenishment method and the conventional development replenisher replenishment method in the above-described embodiment were applied, the variation range of the developer sensitivity was experimentally determined.

[Processing of Examples 1 to 10]
As shown in Tables 3 and 4, the replenishing method of the present invention was used for continuous processing to evaluate developer sensitivity stability. A replenishment ratio that is a ratio of a replenishment amount with time calculated from an operation time and a stop time of the automatic developing device to a total replenishment amount and a replenisher that is a ratio of the development replenisher replenished to the developer in the developer. When the conductivity value calculated from the substitution rate is used as the conductivity reference value, the conductivity value calculated from the processing amount of the photosensitive lithographic printing plate that has been replenished with the replenisher a and processed is used as the conductivity reference value. When used as a replenisher, the replenisher b is replenished. Evaluation of development sensitivity stability depends on how much the image density of an image having a gradation density of 50% exposed by halftoning (AM screening, number of screen lines = 175 lpi) on the photosensitive material changes after development processing. went. The results are shown in Table 5.

[Processing of Comparative Examples 1 to 4]
The area sensitivity reference replenishment method or replenisher (1) a or replenisher (1) b was used for continuous processing to evaluate developer sensitivity stability. As an evaluation of development sensitivity stability, how much the image density of an image having a gradation density of 50% exposed by halftoning (AM screening, number of screen lines = 175 lpi) on a photosensitive material changes after development processing. confirmed. The results are shown in Table 3.

  As a result of the above evaluation, Examples 1 to 4 using the method of the present invention were compared with Comparative Examples 1 to 4 in which the change in 50% gradation density exceeded the allowable range of −1.5% to + 1.5%. In 10, it was confirmed that the change in 50% gradation density was within the allowable range.

It is a block diagram of 1st Embodiment of the automatic processor which implements the developing solution replenishment method concerning this invention. It is a flowchart explaining the basic control processing which replenishes development replenisher. It is a flowchart explaining the 1st control processing which showed the basic control processing of FIG. 2 concretely. It is a flowchart explaining a 2nd control process. It is a flowchart explaining a 3rd control process. It is a block diagram of the automatic processor which concerns on 2nd Embodiment of this invention.

Explanation of symbols

2,100 automatic developing machine 4,112 PS plate 6,122 developing unit 20,118 developing tank 50 control device 51a control ROM
51b Control RAM
52 Time measuring unit 53 Replenishment diluent storage tanks 55 and 266 Replenishment stock solution storage tanks 73 and 262 Conductivity sensors 74 and 264 Replenishment stock solution supply pump 76 Replenishment diluent supply pumps 90 and 91 Replenishment piping

Claims (3)

  A method of developing a plurality of photosensitive lithographic printing plates subjected to exposure treatment with a developer containing an electrolyte and a development inhibitor, and maintaining the developer activity constant, measuring the conductivity of the developer, When the developer conductivity value is lower than the conductivity reference value by comparing the developer conductivity value with a predetermined conductivity reference value, the developer is replenished with a higher conductivity than the developer. A developing solution replenishing method for an automatic developing device, comprising replenishing a developing replenishing solution having a higher development inhibitor concentration and higher electrical conductivity than the developing solution and the developing solution.   When the conductivity value calculated from the processing amount of the photosensitive lithographic printing plate processed in the developer as the conductivity reference value is used as the conductivity reference value, the concentration of the development inhibitor is larger than that of the developer, and 2. The developer replenishing method according to claim 1, wherein the developer replenisher having high conductivity is replenished.   As the electrical conductivity reference value, the time-dependent replenishment ratio, which is the ratio of the time-dependent replenisher amount calculated from the operation time and stop time of the automatic developing device to the total replenishment amount, and the developer replenisher replenished to the developer in the developer 2. The developer replenisher having a higher conductivity than the developer is replenished when the conductivity value calculated from the replenisher replacement rate, which is a ratio of 1, is used as the conductivity reference value. Development replenishment method.

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