JP3777848B2 - Lithographic printing plate material and method for producing a lithographic printing plate using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming material for printing, a planographic printing plate material, and a method for producing a planographic printing plate using the same.
[0002]
[Prior art]
In the conventional printing process, a negative or positive film is produced from an original image, and the image is exposed to a lithographic printing plate material having a photosensitive layer on an aluminum grain support through the film, and then developed with an alkaline developer. In this way, a lithographic printing plate was produced and attached to a printing machine for printing.
[0003]
In recent years, with the spread of computers, computer-to-plate (CTP) technology that draws electronic data of original images directly on a printing plate without using a film or the like is becoming widespread, reducing the time required for film production. Cost reduction is becoming possible. The lithographic printing plate materials required for these technologies include those having a photopolymerizable photosensitive layer on an aluminum grained support and those using silver salts, but these materials are alkaline for image formation. Use developer.
[0004]
Also, in synchronization with the spread of CTP, the working environment at the printing site has become an office, and lithographic printing plate materials that do not require alkali development are desired from the viewpoint of environmental suitability, and further development processing is required at all. Therefore, a planographic printing plate material that has not been developed has been desired.
[0005]
JP-A-9-123387, JP-A-9-123388, JP-A-9-131850, JP-A-9-171249, and JP-A-9-127683 disclose a hydrophilic binder on a printing hydrophilic support. A lithographic printing plate having a layer containing dispersed hydrophobic thermoplastic polymer particles and a method for making the same are disclosed.
[0006]
In these materials, the image part is formed by thermal fusion of hydrophobic thermoplastic polymer particles, and the non-image part is dispersed hydrophobic thermoplastic polymer particles can be removed with water together with a hydrophilic binder. A lithographic printing plate material capable of being subjected to water development can be provided. However, since a hydrophilic binder is mixed in the image area, there is a concern about deterioration of image strength and printing durability.
[0007]
Furthermore, after image drawing, development processing can be performed in the presence of printing ink and / or fountain solution on the cylinder of the printing press, so that it is possible to create a printing plate that does not substantially require a processing processor. However, it takes a considerable time to complete the development. In addition, since the product at the time of development flows into the dampening water of the printing press, contamination of the dampening water supply path is severe and stable dampening water cannot be supplied, resulting in a failure to obtain a stable print quality. There was a problem.
[0008]
[Problems to be solved by the invention]
The present invention has been made to solve the above problems. That is, an object of the present invention is to provide an image forming material, a lithographic printing plate material and a lithographic printing plate material which can be stably supplied with a dampening solution without deterioration of image strength and printing durability, and as a result, can obtain a stable printing quality. The object is to provide a method for producing a lithographic printing plate used.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by adopting one of the following configurations.
[0010]
[1] Two or more kinds of polymer particles having different MFTs (minimum film forming temperature) satisfying the following conditions 1) and 2) on the hydrophilic support for printing, and the content weight of the polymer particles exhibiting the lowest MFT And an image forming layer containing the polymer particles exhibiting the second lowest MFT in a ratio of 60:40 to 10:90, and a photothermal conversion agent in the image forming layer and / or the support. containing, planographic printing plate material, characterized in that the image forming is performed by at least one heat-sealable of the polymer particles.
1) 25 ° C. <lowest MFT of polymer particles ≦ 75 ° C.
2) 90 ° C. ≦ second lowest MFT of polymer particles ≦ 150 ° C.
[0016]
[2] The image forming layer only polymer particles, or characterized by comprising the only polymer particles and a photothermal conversion agent (1) Symbol placement planographic printing plate material.
[0018]
[ 3 ] A lithographic printing plate material, wherein the lithographic printing plate material described in [ 1] or [2 ] is fixed to a cylinder of a printing machine, and is developed in the presence of at least one of printing ink or fountain solution. A method for preparing a printing plate.
In the following, “image forming material” refers to “lithographic printing plate material” according to the present invention.
[0019]
The image forming layer of the present invention mainly contains polymer particles, a hydrophilic binder, a photothermal conversion agent and the like.
[0020]
Examples of the polymer particles that can be used in the present invention include those in the form of aqueous dispersions such as latexes and emulsions of various resins. Examples of the resin constituting the polymer particles include acrylic resins, ionomer resins, and vinyl acetate resins. , Vinyl chloride resins, synthetic rubbers, polyurethane resins, polyester resins, fluorine resins, silicone resins, waxes and the like.
[0021]
Examples of the acrylic resin that can be used in the present invention include copolymers having an acrylic ester and methacrylic acid as essential components, such as methyl methacrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, Examples include those obtained by copolymerizing styrene or the like.
[0022]
Synthetic rubbers that can be used in the present invention include polybutadiene, polyisoprene, polychloroprene, styrene-butadiene copolymer, acrylic ester-butadiene copolymer, methacrylic ester-butadiene copolymer, and isobutylene-isoprene copolymer. Examples thereof include a polymer, an acrylonitrile-butadiene copolymer, an acrylonitrile-isoprene copolymer, and a styrene-isoprene copolymer.
[0023]
The waxes that can be used in the present invention include carnauba wax, beeswax, whale wax, wood wax, jojoba oil, lanolin, ozokerite, paraffin wax, montan wax, candelin wax, ceresin wax, microcrystalline wax, rice wax. And natural waxes such as polyethylene wax, Fischer-Tropsch wax, montan wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives, higher fatty acids and the like.
[0024]
The content of the polymer particles in the image forming layer is 70 wt% or more, preferably 95 wt% or more, more preferably 100 wt% in order to enable image formation.
[0025]
The image forming layer in the present invention preferably contains at least two types of polymer particles, and particularly includes polymer particles having different minimum film forming temperatures (MFTs), preferably MFTs different by 15 ° C. or more. What you have is good.
[0026]
More preferably, the MFT of the polymer particles is
(1) 25 ° C. <lowest MFT of polymer particles ≦ 75 ° C.
(2) The second lowest MFT of polymer particles is 90 ° C. or higher.
It is preferable to have the relationship of
(3) The melting point of the polymer particles exhibiting the second lowest MFT is 150 ° C. or lower,
It is preferable that
[0027]
By containing the polymer particles of the above condition (1) in the image forming layer, an appropriate film forming property is imparted, the scratching property is improved, and the handling property of the image forming material is improved. Further, since fusion can be performed at a low temperature, it contributes to image formation with a small exposure energy.
[0028]
Further, by containing the polymer particles of the above conditions (2) and (3) in the image forming layer, a hard component can be imparted to the image portion, and the printing durability can be improved. In the non-image area, fusion at low temperature can be prevented, and fogging during storage can be prevented. In order for the polymer particles to have the above conditions, the resin composition is selected. In particular, the above-mentioned styrene-acrylic copolymer resin and wax particles are suitable as polymer particles that satisfy the conditions (2) and (3).
[0029]
The minimum film formation temperature (MFT) of the polymer particles can be measured, for example, by the method described in “Polymer Latex Chemistry” (by Soichi Muroi; Polymer Press Society). That is, the polymer particle dispersion is thinly cast on an aluminum plate having a temperature gradient from high temperature to low temperature and dried. Since transparency is obtained when the polymer particles are deposited, the temperature of the aluminum plate at the point at which it begins to become transparent is measured, and this is set as the minimum deposition temperature.
[0030]
The weight ratio of the polymer particles contained in the image forming layer satisfying the conditions of (1) and (2) is preferably 60:40 to 10:90. Sexual balance may be difficult to obtain.
[0031]
In order to improve the film property, the image forming layer of the present invention may contain a small amount of a hydrophilic binder. Known hydrophilic binders can be used, and water-soluble (co) polymers, that is, synthetic homopolymers or copolymers are used. For example, polyvinyl alcohol, poly (meth) acrylic acid, poly (meth) acrylamide, polyhydroxyethyl (meth) acrylate, polyvinyl methyl ether, or natural binders such as gelatin, polysaccharides, dextran, pullulan, cellulose, gum arabic, arginine Such as acids. The hydrophilic binder may be a water-insoluble, alkali-soluble or swellable resin having a phenolic hydroxy group and / or a carboxyl group.
[0032]
In the present invention, the content of the hydrophilic binder is preferably as small as possible in order to accelerate the developability on the printing press and to prevent the printing press from being contaminated. It is preferable to contain 5 wt% or less of the constituent components of the image forming layer, and not to contain at all. When the amount of the hydrophilic binder exceeds 5 wt%, the developing property on the printing press is slow, and when it is 5 wt% or less, the developing property on the printing press is accelerated. This is because when the hydrophilic binder content is high, dissolution of the hydrophilic binder by dampening water greatly contributes to development, and when the hydrophilic binder content is low, the viscous ink for printing is used. It is assumed that the polymer particles are peeled off from the support due to the difference in development mechanism that greatly contributes to development.
[0033]
If the amount of the hydrophilic binder exceeds 5 wt%, the polymer particles in the developed product tend to be mixed into the dampening water together with the hydrophilic binder. It will contaminate the parts.
[0034]
The image forming layer of the present invention may contain a photothermal conversion agent that absorbs laser light and converts it into heat for laser recording. Examples of the photothermal conversion agent include carbon black, titanium black, metal carbide, boride, nitride, carbonitride, bronze structure oxide, and oxide that is structurally related to the bronze genus but has no A component, such as WO _2.9 , conductive Conductive polymer dispersions, for example, conductive polymer dispersions based on polypyrrole or polyaniline, organic compounds such as cyanine, polymethine, azurenium, squalium, thiopyrylium, naphthoquinone, anthraquinone dyes, phthalocyanine, azo, thioamide An organic metal complex or the like is preferably used.
[0035]
Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-280750, JP-A-1-293342, JP-A-2-2074, JP-A-3-26593, 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, etc. And the compounds described in the above.
[0036]
As the support for the image forming material of the present invention, known materials can be used, for example, metal plates such as aluminum, stainless steel, chromium, nickel, or plastic films such as polyester film, polyethylene film, polypropylene film, paper, synthetic paper, etc. A resin-coated paper obtained by laminating or vapor-depositing the above metal thin film, such as a polyester film, a vinyl chloride film, or a nylon film, can be used.
[0037]
These supports can be provided with a photothermal conversion function for laser recording. For example, carbon black or gold, silver or aluminum described in JP-A-52-20842 can be formed on the support. , Chromium black, nickel, antimony, tellurium, bismuth, selenium and other metal black vapor deposition layers and methods for forming vapor deposition films. Moreover, in the case of a plastic film, the method of kneading and mixing the photothermal conversion agent mentioned above before film formation is also mentioned.
[0038]
The image forming material of the present invention can also use a printing hydrophilic support as the support. Examples of the hydrophilic support for printing include an aluminum plate having a grained surface, anodized, and sealed. Examples of the graining method include a mechanical method and a method of etching by electrolysis. Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a buff polishing method.
[0039]
The various methods described above can be used alone or in combination depending on the composition of the aluminum material. A method by electrolytic etching is preferable. Electrolytic etching is performed in a bath in which inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid are used alone or in combination. After the graining treatment, if necessary, it is desmutted with an alkali or acid aqueous solution, neutralized and washed with water.
[0040]
The anodizing treatment is performed by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution, and electrolyzing the aluminum plate as an anode. The formed anodic oxidation coating amount is suitably 1 to 50 mg / dm ² , preferably 10 to 40 mg / dm ² . Specific examples of the sealing treatment include boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and the like.
[0041]
In addition, the aluminum plate support can be subjected to a subbing treatment with an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconic acid. The hydrophilic support has a surface contact angle with water of 60 degrees or less, more preferably 40 degrees or less.
[0042]
A hydrophilic support having a thickness of 50 to 1000 μm, preferably 75 to 500 μm, can be suitably used.
[0043]
It is preferable to use an aluminum support whose surface roughness on the photosensitive layer side is in the range of 0.2 to 0.8 μm in Ra and / or in the range of 3.0 to 6.0 μm in Rz. The hydrophilic support subjected to the sealing treatment can be hydrophilized with sodium silicate or the like.
[0044]
The hydrophilic support for printing can also be produced by coating a hydrophilic layer on the above-described support. Examples of the hydrophilic layer include those obtained by crosslinking a hydrophilic binder, and those obtained by self-forming high hydrophilic particles such as metal oxide fine particles.
[0045]
Examples of the hydrophilic binder constituting the hydrophilic layer include hydrophilic (co) polymers such as polyvinyl alcohol, acrylamide, methylol acrylamide, methylol methacrylamide, acrylic acid, methacrylic acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate. Acrylic resins such as polymers or copolymers, maleic acid / vinyl methyl ether copolymers, polyesters, polyurethanes, celluloses, gelatin, and the like can be used.
[0046]
As the crosslinking agent for crosslinking the hydrophilic binder, for example, melamine resin, formaldehyde, glyoxal, polyisocyanate, hydrolyzed tetra-alkylorthosilicate, and the like can be used.
[0047]
Examples of the metal oxide fine particles include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle diameter is preferably 3 to 100 nm, and several kinds of metal oxide fine particles having different average particle diameters can be used in combination. Moreover, surface treatment may be performed on the particle surface. Among the above, colloidal silica is particularly preferable because of its high film forming property even under relatively low temperature drying conditions.
[0048]
The hydrophilic layer may contain porous inorganic particles in order to improve hydrophilicity and water retention and to make the surface roughness of the hydrophilic layer within a suitable range. As the porous inorganic particles, porous silica, porous aluminosilicate particles, or zeolite particles are preferable. Moreover, it is preferable that a porous particle is 30-95 wt% of the whole coating layer.
[0049]
The porosity of the particles is preferably 1.0 cc / g or more in terms of pore volume, more preferably 1.2 cc / g or more, and further 1.8 to 2.2. It is preferably 5 cc / g.
[0050]
The particle diameter of the porous inorganic particles is preferably substantially 1 μm or less, more preferably 0.5 μm or less, when contained in the hydrophilic layer. In order to remove coarse porous inorganic particles larger than 1 μm, the hydrophilic layer coating liquid may be mechanically dispersed to crush the coarse particles.
[0051]
The hydrophilic layer can be provided with a photothermal conversion function for laser recording, and can contain the photothermal conversion agent described above.
[0052]
The image forming material of the present invention may be provided with a latent image by a thermal head. When the image forming layer and / or the support has a photothermal conversion function, recording with a laser beam is also possible. Examples of the laser light source include an argon laser, a He—Ne gas laser, a YAG laser, and a semiconductor laser.
[0053]
The image forming material provided with the latent image can be developed with water or an alkaline developer. When a hydrophilic support is used as the support, in addition to the development processing method described above, the image forming material is attached to a cylinder of a printing press, and the ink for printing and / or the fountain for printing is used while rotating the cylinder. Can be developed on a printing press. Similarly, after the cylinder is rotated several times while supplying the printing ink and / or the dampening solution for printing, the printing paper is transported to remove the developer with the printing paper. I can do it. Furthermore, after mounting the image forming material on the cylinder, it is developed on the printing machine by suddenly entering the printing state (supplying the printing ink, supplying the dampening water for printing, and transporting the paper simultaneously with the rotation of the cylinder). I can do it.
[0054]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further, the aspect of this invention is not limited to this.
[0055]
Preparation of hydrophilic support 1
After a corona discharge treatment was performed on a PET film having a thickness of 200 μm under the condition of 15 W / (m ² · min), an undercoat layer coating solution having the following composition was applied to the corona surface using a wire bar # 9, and 150 A support having an undercoat layer having a dry film thickness of about 3 μm was obtained by drying at 10 ° C. for 10 minutes.
[0056]
-Undercoat layer composition-
The following composition was mill-dispersed with glass beads for 1 hour to obtain a hydrophilic layer coating solution. The obtained coating solution was applied with a wire bar # 10 and dried at 100 ° C. for 10 minutes to obtain a support having a hydrophilic layer having a dry film thickness of about 3 μm.
[0057]
Preparation of hydrophilic support 2
After a corona discharge treatment was performed on a PET film having a thickness of 200 μm under the condition of 15 W / (m ² · min), an undercoat layer coating solution having the following composition was applied to the corona surface using a wire bar # 9, and 150 A support having an undercoat layer having a dry film thickness of about 3 μm was obtained by drying at 10 ° C. for 10 minutes.
[0058]
The following composition was mill-dispersed with glass beads for 1 hour to obtain a hydrophilic layer coating solution. The obtained coating solution was applied with a wire bar # 10 and dried at 100 ° C. for 10 minutes to obtain a support having a hydrophilic layer having a dry film thickness of about 3 μm.
[0059]
Preparation of hydrophilic support 3
A 0.24 mm thick aluminum plate (material 1050, tempered H16) was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water. This degreased aluminum plate was neutralized by immersion in a 10% aqueous hydrochloric acid solution maintained at 25 ° C. for 1 minute, and then washed with water.
[0060]
Next, this aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds in a 0.3 wt% nitric acid aqueous solution at a temperature of 25 ° C. and a current density of 100 A / dm ² , and then kept at 60 ° C. 5 The desmutting treatment was performed in a 10% aqueous sodium hydroxide solution for 10 seconds.
[0061]
The surface-roughened aluminum plate subjected to desmut treatment was anodized in a 15% sulfuric acid solution at a temperature of 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute, and further 3% sodium oxalate, Sealing treatment was performed at 90 ° C. to prepare hydrophilic support 1. Ra on the support after silicic acid treatment was 0.43 μm.
[0062]
Polymer particle aqueous dispersion 1
A 1,000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube and reflux condenser, and 350 cc of distilled water is added while introducing nitrogen gas and deoxidizing, and the internal temperature becomes 80 ° C. Heated until.
[0063]
3.5 g of sodium lauryl sulfate was added as a dispersant, 0.45 g of ammonium persulfate was added as an initiator, and then the following monomer composition 1 was dropped over about 1 hour with a dropping funnel. After the completion of the dropwise addition, the reaction was continued as it was for 5 hours, and then the unreacted monomer was removed by steam distillation. Thereafter, the mixture was cooled and adjusted to pH 7 with aqueous ammonia, and finally pure water was added so that the nonvolatile content was 50 wt% to obtain an aqueous dispersion-1 of polymer particles.
[0064]
The obtained polymer particle aqueous dispersion was applied to an aluminum plate and dried at room temperature. This was put in a heater and heated at 25 ° C. to 2 ° C./min. As a result of confirming the temperature (MFT) at which the polymer particles melt and become transparent into a film, it was 60 ° C. Moreover, as a result of measuring melting | fusing point by differential thermal analysis, melting | fusing point was 63 degreeC.
[0065]
Monomer composition 1
Styrene 60g
Butyl acrylate 25g
Methacrylic acid 5g
Polymer particle aqueous dispersion 2
An aqueous dispersion of polymer particles was produced in the same manner except that the monomer composition of the aqueous dispersion 1 of polymer particles was changed to the following. The obtained polymer particles had an MFT of 68 ° C. and a melting point of 71 ° C.
[0066]
Monomer composition 2
65g of styrene
Butyl acrylate 20g
Methacrylic acid 5g
Polymer particle aqueous dispersion 3
An aqueous dispersion of polymer particles was produced in the same manner except that the monomer composition 1 of the aqueous dispersion 1 of polymer particles was changed to the following. The obtained polymer particles had an MFT of 81 ° C. and a melting point of 85 ° C.
[0067]
Monomer composition 3
70g of styrene
Butyl acrylate 15g
Methacrylic acid 5g
Polymer particle aqueous dispersion 4
An aqueous dispersion of polymer particles was produced in the same manner except that the monomer composition 1 of the aqueous dispersion 1 of polymer particles was changed to the following. The obtained polymer particles had an MFT of 95 ° C. and a melting point of 102 ° C.
[0068]
Monomer composition 4
Styrene 75g
Butyl acrylate 10g
Methacrylic acid 5g
Image Formation Layer As shown in Table 1, the following image formation layer coating solutions were applied on a hydrophilic support with a wire bar # 5, dried at 50 ° C. for 3 minutes and laminated to obtain a lithographic printing plate material. The image forming layer was about 1.0 g / m ² by dry weight.
[0069]
Content of Evaluation-Image Forming Layer Coating Film Strength-
The strength of the image forming layer coating film of the produced lithographic printing plate material was evaluated as follows by rubbing with a finger.
[0070]
○… A level that can be used for printing without any rub marks on the fingers.
Δ: There is a rubbing mark on the finger, but it can be used for printing,
X: Level at which the image forming layer is missing in the form of a rubbing finger and cannot be used for printing.
[0071]
Next, the produced lithographic printing plate material was subjected to image exposure with a semiconductor laser (wavelength 830 nm, output 100 mW). The laser beam diameter was 13 μm at 1 / e ² of the intensity at the peak. The resolution was 2000 dpi in both the scanning direction and the sub-scanning direction.
[0072]
The lithographic printing plate on which the image has been drawn is placed in a cylinder of a printing machine (Heidel GTO) without developing, and a 45-fold water diluted solution of SEU-3 (manufactured by Konica) is used as an etchant, and HyEcho Red (Toyo Ink) is used as an ink. Printing was performed using a product manufactured by Manufacturing Co., Ltd.
[0073]
Evaluation item-developability-
The point at which the non-image portion reflection density of the obtained printed matter was 0.05 or less was used as the development end point, and the number of printed sheets from the start of printing until the reflection density was 0.05 or less was used as an index of developability.
[0074]
-Sensitivity-
The amount of exposure energy at which fine lines corresponding to 175 lines were clearly obtained in the image on the printed material after development was used as an index of sensitivity of the planographic printing plate material.
[0075]
-Printing durability-
The number of printed sheets until an image on a printed material was blurred on a thin line corresponding to 175 lines was used as an index of printing durability.
[0076]
-Evaluation of storage stability-
The developability of the planographic printing plate stored for 3 days in an environment of relative humidity 80% and 40 ° C. was evaluated in the same manner as described above.
[0077]
-Evaluation of contamination of printing press-
Each lithographic printing plate material was continuously developed on a printing machine 5 times, and then dried by allowing the malton for supplying dampening water to stand for 24 hours. The dried molton was placed in a printing machine again, printed using a positive PS plate VS (Fuji Photo Film Co., Ltd.), and evaluated as follows.
[0078]
○: Water absorption is not deteriorated, and the non-image area is not stained from the beginning of printing.
Δ: The water absorption was deteriorated in the initial stage of printing, but it recovered to the original water absorption with time, and was sufficiently usable for printing.
X: No level of water absorption, water cannot be supplied during printing, and cannot be used.
[0079]
The results are shown in Table 1 below.
[0080]
[Table 1]
[0081]
As in the present invention, by using an image forming layer containing polymer particles having different MFTs, the coating strength and printing suitability such as printing durability and developability were improved. Further, by not containing a hydrophilic binder in the image forming layer, the developability was further improved and the contamination of the printing press was also reduced.
[0082]
【The invention's effect】
According to the present invention, an image forming material, a lithographic printing plate material, and a lithographic printing using the image forming material, which can stably supply dampening water without deteriorating image strength and printing durability, and can obtain a stable printing quality as a result. A method for producing a plate can be provided.

Claims (3)

Two or more types of polymer particles having different MFTs (minimum film forming temperatures) satisfying the following conditions 1) and 2) on the hydrophilic support for printing are compared with the content weight of the polymer particles exhibiting the lowest MFT. The polymer particles having a low MFT content ratio of 60:40 to 10:90, and the image forming layer and / or the support further contains a photothermal conversion agent. The lithographic printing plate material is characterized in that an image is formed by at least one kind of heat-fusibility of the polymer particles.
1) 25 ° C. <lowest MFT of polymer particles ≦ 75 ° C.
2) 90 ° C. ≦ second lowest MFT of polymer particles ≦ 150 ° C. 2. The lithographic printing plate material according to claim 1, wherein the image forming layer comprises only polymer particles or only polymer particles and a photothermal conversion agent. A lithographic printing plate material according to claim 1 or 2 is fixed to a cylinder of a printing press and developed in the presence of at least one of printing ink or fountain solution. Method.