JP2005254654A - Manufacturing method of original plate for lithographic printing, original plate for lithographic printing and printing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an original plate for lithographic printing, for forming a stable, excellent coating face with a uniform surface shape free from a coating defect on a long-sized strip-like substrate by using a bar coating device, an original plate for lithographic printing and a printing method using the same. <P>SOLUTION: In the manufacturing method of the original plate for lithographic printing for manufacturing the original plate by forming at least a hydrophilic layer containing particles and having an uneven surface on the hydrophilic layer and an image forming layer on the substrate in the order named, the method comprises the steps of excessively coating a coating liquid having a viscosity controlled within a range described below for forming the image forming layer on the substrate continuously conveyed and having the hydrophilic layer coated thereon and scraping off the excess coating liquid by using the bar to form the image forming layer: the temperature of the liquid is to be controlled to make the viscosity of the liquid fall within a range of A±40A, wherein the viscosity of the coating liquid at 20°C is represented by A (mPa s). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a method for producing a lithographic printing plate precursor capable of image recording based on a digital signal, a lithographic printing plate precursor, and a printing method using the same.

  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 (lithographic printing original plate) having an image forming layer on an aluminum grained support through the film, and is alkaline. A lithographic printing plate is produced by developing with a developing solution, and this is carried out by a procedure of attaching it to a printing machine and printing.

  In recent years, with the spread of computers, computer-to-plate (CTP) technology that draws original image data directly on a printing plate without using a film is becoming widespread, reducing the time and cost required for film production. Is becoming possible. In addition, as a need for printed materials, there has been a tendency for a small number of various types of products to print various high-quality images with the number of printed sheets of about several thousand to 10,000 sheets. For this reason, plate making using heat mode laser recording, which has a short drawing time and high resolution, is becoming the mainstream of CTP.

  Synchronizing with the spread of CTP, the printing environment has become an office, and from the viewpoint of environmental suitability, a lithographic printing plate material that does not require an alkaline developer and does not require any development treatment has been desired. I came.

  For example, in JP-A-9-123387, JP-A-9-123388, and JP-A-9-131850, a lithographic printing plate precursor containing thermoplastic particles dispersed in a hydrophilic binder is attached to a printing machine. A method for producing a planographic printing plate by developing on a printing press is disclosed. According to these techniques, it is possible to produce a printing plate without performing alkali development and without requiring a developing machine, and it is possible to provide a lithographic printing plate that does not require development processing in a pseudo manner.

  In lithographic printing plate precursors, it has recently been studied to use a plastic film as a support without using a hydrophilic aluminum substrate as a support.

  Plastic film has low thermal conductivity compared to metal and can be used for image formation efficiently without diffusing heat generated in the heat-sensitive image forming layer by laser exposure during image formation to the support, Furthermore, it has the advantage of being inexpensive compared to an aluminum support.

  JP-A-9-314794 discloses examples of using a support having a corona-treated surface as a printing plate using these plastic films as a support, and JP-A-11-245530 discloses a plasma treatment. A support is disclosed.

  Various apparatuses are known as a coating apparatus for coating an image forming layer on a plastic film support. For example, dip coating, roll coating, fountain coating, air knife coating, blade coating, bar coating, slide hopper coating, etc.

  As a method of applying easily and stably to a support that is continuously conveyed in the coating method using the coating device, a bar coating device has been used in recent years. Bar coating methods are known.

  In the bar coating method, as a first step, an appropriate amount of coating solution is applied to the support by a roll coating device or the like, and the bar coating device (the bar is stationary or rotating) is applied to the excess coating solution (primary film). This is a method of obtaining a desired film thickness (secondary film) by pressing a bar and scraping off an excessive coating liquid, and can also be applied to a case where the film is applied to a belt-like long support. In the bar coating method, the final film thickness after scraping is determined only by the cut surface of the groove formed in the bar.

  In the production of an original plate for lithographic printing, there is a description describing the content of providing an undercoat layer containing specific metal oxide particles on a support by bar coating (see Patent Documents 1 and 2).

  On the other hand, for the coating of the hydrophilic layer of the lithographic printing original plate, an invention using a coating solution in which inorganic particles are contained in a resin has attracted attention. This is because the adhesion between the support and the hydrophilic layer is improved, and the printing durability, scratch resistance and stain resistance can be improved (see Patent Document 3 and Patent Document 4).

However, the lithographic printing plate precursor having such a type of hydrophilic layer is likely to cause omission and vertical stripes in the vicinity of the particles protruding from the hydrophilic layer in the step of applying the image forming layer on the hydrophilic layer. There is a problem.
Japanese Patent Laid-Open No. 14-154278 Japanese Patent Laid-Open No. 15-175359 JP 2001-113848 A JP 2001-213063 A

  As described above, in the conventional invention, a lithographic printing original plate having an image forming layer having good coating properties and stable performance without requiring a special bar coating device and without particularly changing the coating solution. Since the bar coating production conditions were not described, it was necessary to establish them.

  An object of the present invention is to provide a lithographic plate having an image-forming layer having a stable and good coated surface having a uniform surface shape with no coating defects on a long belt-like support using a bar coating device. An object of the present invention is to provide a method for producing a printing original plate, a planographic printing original plate, and a printing method using the same.

  As a result of intensive studies, the inventors of the present invention have found that the object of the present invention is achieved by adopting the following configuration.

(Claim 1)
In the method for producing an original plate for lithographic printing comprising, on a support, at least a hydrophilic layer containing particulate matter and having irregularities on the hydrophilic layer surface, and an image forming layer in this order,
In order to form an image forming layer on a support that has been continuously coated with a hydrophilic layer, after applying an excessive amount of the coating liquid adjusted to the following viscosity, A method for producing an original plate for lithographic printing, wherein the coating is performed while scraping off.
Viscosity adjustment of coating solution: When the viscosity of the coating solution at 20 ° C. is A (mPa · s), the coating solution temperature is adjusted to fall within the range of A ± 0.40A.

(Claim 2)
In the method for producing an original plate for lithographic printing comprising, on a support, at least a hydrophilic layer containing particulate matter and having irregularities on the hydrophilic layer surface, and an image forming layer in this order,
In order to form an image forming layer on a support that has been coated with a hydrophilic layer that has been continuously conveyed, after applying an excessive amount of the coating solution, the excess coating solution is applied using a bar under the following conditions. A method for producing an original plate for lithographic printing, wherein the coating is performed while scraping off.
Scraping conditions: If the coating width is T1 (mm) and the bar length is T2 (mm), a bar that falls within the range of 1.20T1 ≦ T2 is used.

(Claim 3)
A lithographic printing plate precursor produced by the method for producing a lithographic printing plate precursor according to claim 1 or 2.

(Claim 4)
A printing method comprising: printing the original plate for lithographic printing according to claim 3 by laser exposure based on image information and performing on-press development processing.

  According to the present invention, it is possible to obtain a stable and good coated surface having no coating defect, uniform surface shape and good performance on a long belt-like support using a bar coating apparatus, and for lithographic printing having a good performance. An original plate manufacturing method, a planographic printing original plate, and a printing method using the same can be provided.

  In the present invention, after applying an excessive amount of coating liquid on a continuously transported support under specific conditions, the excessive amount of coating liquid is scraped off using a bar to perform coating defects. The present invention relates to a method for producing a lithographic printing plate precursor that can provide a stable coated surface even if it is long and has good printing performance, and a lithographic printing plate precursor and a printing method therefor.

  When there is a hydrophilic layer already coated on the surface of the support as in the present invention and there are particles protruding from the hydrophilic layer in the bar coating in which the image forming layer is applied in contact therewith, the image forming layer It was found that controlling the viscosity of the coating solution was extremely effective.

  That is, it was found that it is important to control the leveling property by adjusting the liquid temperature and controlling the viscosity.

  The coating solution for the image forming layer can be applied in a viscosity range of 1 to 300 mPa. In this case, if A (mPa · s) +0.40 A, that is, exceeding 1.4 A, the viscosity becomes too high, so the hydrophilic layer. It turned out that the micro leveling property in the vicinity of the more protruding particle | grains is bad, and as a result, the applicability | paintability in the part which the particle | grain does not protrude is different. This causes the coating property to deteriorate, and the image forming layer surface is missing or has vertical stripes.

  In addition, the viscosity of the coating liquid in the present invention is defined by the viscosity immediately after coating. Therefore, a method of adjusting by controlling the temperature of the coating solution immediately before coating is preferably used, but is not necessarily limited to this method. For example, the viscosity may be adjusted by controlling the temperature of the transport roll and / or the coating drum during coating.

  In the present invention, if it becomes smaller than A-0.40A, that is, 0.60A, the micro leveling property in the vicinity of the particles protruding from the hydrophilic layer is too good, and as a result, a phenomenon called sharking is likely to occur. As a whole, omissions and vertical stripes still occur.

  Further, in the production of a lithographic printing original plate in which a hydrophilic layer having particles protruding from a hydrophilic layer and an image forming layer are sequentially provided on a support, a hydrophilic layer that has been continuously conveyed is already applied. In the bar coating method in which an excessive amount of the image forming layer coating solution is applied onto the provided support, and then the excess image forming layer coating solution is scraped off using a bar, the coating width is set to T1 (mm ) When the length of the bar is T2 (mm), it is important to apply under the condition of 1.20T1 ≦ T2.

  When applying an image forming layer on a hydrophilic layer with particles protruding from the hydrophilic layer in bar coating, the relationship between T1 (mm) and T2 (mm) affects the coating properties and printing performance. It was found to give.

  That is, when T2 is smaller than 1.20T1, it is difficult to uniformly apply pressure to the bar on the hydrophilic layer where there are particles protruding from the hydrophilic layer, and the frictional force is not uniform with respect to the base width. As a result, it was found that the applicability becomes extremely unstable depending on the production conditions such as the number of rotations of the bar and the coating speed.

  For this reason, it is important to perform bar coating in the range of 1.20T1 ≦ T2.

  The size of T2 is not particularly limited, but is preferably up to 2T1 from the viewpoint of bar management.

  Hereinafter, the present invention will be described in detail.

[Image forming layer coating solution temperature]
There is no particular limitation on the means for changing the temperature of the image forming layer coating solution. However, a method of pre-warming through a warm water jacket, a method of increasing the coating solution temperature as a result of receiving heat from the latent heat of the substrate after passing through the drying temperature, etc. There is.

[Bar application]
The bar used in the present invention may be either a wire wound around a metallic rod or a wireless bar not wound with a wire.

  A wireless bar is not a bar made by winding a wire, but a bar that does not use a wire made by rolling using a screw rolling round die.

  The surface of the bar used in the present invention may be plated.

  The surface plating treatment species may be used without particular limitation as long as it satisfies the scope of the present invention, and examples thereof include nickel, cobalt, hard chromium, titanium, and DLC (diamond-like carbon). The plating treatment may be performed singly or a plurality of plating treatments such as a hard chrome plating treatment may be performed on the nickel plating treatment.

  Any of the above coating devices can be used as a device for applying an excessive coating liquid in combination with a bar coating device, but in general, a dip coating device, a roll coating device, a fountain coating device, a comma coating device. Etc. are used. Also, a coating apparatus in which the overcoating and the bar coating apparatus are integrated as described in JP-A-6-170312 may be used.

[Particles]
An example of the particulate matter that protrudes further from the hydrophilic layer is a filler.

Carbon black, graphite, TiO ₂ , BaSO ₄ , ZnS, MgCO ₃ , CaCO ₃ , ZnO, CaO, WS ₂ , MoS ₂ , MgO, SnO ₂ , Al ₂ O ₃ , α-Fe ₂ O ₃ , α-FeOOH, _{SiC, CeO 2, BN, SiN} , MoC, BC, WC, titanium carbide, corundum, artificial diamond, garnet, garnet, silica rock, tripoli, diatomaceous earth, an inorganic filler and polyethylene resin particles, such as dolomite, fluororesin particles, Examples include organic fillers such as guanamine resin particles, acrylic resin particles, silicon resin particles, and melamine resin particles.

  Examples of the filler include inorganic fine particles and organic resin particles, and these may also serve as a release agent. Examples of the inorganic fine particles include silica gel, calcium carbonate, titanium oxide, acidic clay, activated clay, and alumina. Examples of the organic fine particles include resin particles such as fluororesin particles, guanamine resin particles, acrylic resin particles, and silicon resin particles. Can be mentioned.

  Examples of the particulate material include a filler having a core-shell structure.

  The particles having a core-shell structure are particles obtained by fixing particles to a portion that becomes a shell on the surface of the core particles.

  The core particles and the particles that become the shell may be inorganic particles or organic particles. The core particles may be fixed (coated) in a number of layers with the shell particles. The average particle diameter of the core particles is preferably from 0.1 to 15 μm, more preferably from 1 to 10 μm.

  Further, the surface irregular particles may be used. In this case, the average particle size of the small particles is preferably 1/3 or less, more preferably 1/10 or less, of the average particle size of the core particles. The average particle diameter of the surface irregular particles is preferably not more than 15 μm, and preferably 0.1 μm or more.

  The coverage of the small particles fixed on the surface of the core particles can be arbitrarily selected within the range in which the effect of the present invention appears.

  For example, the surface irregularity particle is a method using the agglomeration method described in “Fine particle polymer” edited by Toray Research Center, Inc., a method using a polymerization reaction from the surface of the core particle, It can be easily produced using a dry coagulation stirring method using a dither, or the like. Certain core-shell particles can also be produced by precipitating small particles on the surface of the core particles.

  Examples of the particulate material include wax.

  Specific examples of the wax include solid waxes such as beeswax, candelilla wax, paraffin wax, ester wax, montan wax, carnauba wax, amide wax, polyethylene wax, and microcrystalline wax.

  Specific compounds as silicon compounds (including wax-like compounds) include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil, olefin-modified silicone oil, polyether-modified silicone oil, and epoxy. Modified silicone oil, epoxy-polyether modified silicone oil, alcohol modified silicone oil, fluorine modified silicone oil, amino modified silicone oil, phenol modified silicone oil, mercapto modified silicone oil, carboxy modified silicone oil, higher fatty acid modified silicone oil, carnauba modified Radical reactive silicone oil such as silicone oil, amide modified silicone oil, (meth) acrylic modified silicone oil, silicone diol, Terminal reactive silicone oil such as Njiamin, a halogen group, an alkoxy group, and an ester group, an amide group, an organic modified silicone oil modified with an imide group.

  Examples of the particulate material include metal atom-containing particles.

  The metal atom-containing particles are a general term for compounds such as metals such as iron, chromium, manganese, cobalt, nickel, copper, zinc, titanium, silver, aluminum, gold, and platinum, or oxides thereof.

  Examples of the metal atom-containing particles include ferromagnetic iron oxide powder, ferromagnetic metal powder, and cubic plate powder.

Examples of the ferromagnetic iron oxide include γ-Fe ₂ O ₃ , Fe ₃ O ₄ , or intermediate iron oxides represented by FeOx (1.33 <x <1.50).

Ferromagnetic metal powders include Fe, Co, Fe—Al, Fe—Al—Ni, Fe—Al—Zn, Fe—Al—Co, Fe—Al—Ca, Fe—Ni. Fe-Ni-Al, Fe-Ni-Co, Fe-Ni-Zn, Fe-Ni-Mn, Fe-Ni-Si, Fe-Ni-Si-Al-Mn, Fe-Ni -Si-Al-Zn, Fe-Ni-Si-Al-Co, Fe-Al-Si, Fe-Al-Zn, Fe-Co-Ni-P, Fe-Co-Al-Ca Ferromagnetic metal powders such as metal magnetic powders mainly composed of Ni, Co, Fe, Ni, Co, etc. Among them, Fe metal powders are preferred, for example, Co-containing γ-Fe ₂ O ₃ , Co coated Adhered γ-Fe ₂ O ₃ , Co-containing Fe ₃ O ₄ , Co-coated Fe ₃ O ₄ , Co-containing magnetic Fe Examples include cobalt-containing iron oxide magnetic powders such as Ox (4/3 <x <3/2) powders.

[Support]
The support used in the present invention is not particularly limited, and paper treated with metal, plastic film, polyolefin, etc., and a composite substrate obtained by appropriately bonding these materials can also be used.

  Examples of the plastic film include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polypropylene, polyethylene, polyvinyl chloride, acetate, nylon, polyetherimide, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, and cellulose esters. it can.

  These plastic films are preferably subjected to easy adhesion treatment or undercoat layer coating on the coated surface in order to improve the adhesion to the coated layer. Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, and ultraviolet irradiation treatment. Examples of the undercoat layer include a layer containing gelatin or latex.

〔binder〕
The binder used in the image forming layer and other layers used in the present invention can be used without any particular limitation.

  Binder resins include polyurethane, polyester, vinyl chloride resins such as vinyl chloride copolymers, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymers, polyolefin resins such as butadiene-acrylonitrile copolymers, polyvinyl Polyvinyl acetal resin such as butyral, cellulose resin such as nitrocellulose, styrene resin such as styrene-butadiene copolymer, acrylic resin such as polymethyl methacrylate, polyamide, phenol resin, epoxy resin, phenoxy resin, polyvinyl butyral And acetal resins such as polyvinyl acetoacetal and polyvinyl formal, and water-soluble resins such as polyvinyl alcohol and gelatin.

  The binder resin may be used alone or in combination of two or more.

(Image forming layer)
The image forming layer of the lithographic printing plate precursor according to the invention can be selected and contained from heat-fusible particles that can be fused by heat and substances that exhibit lipophilicity by heat.

  Examples of heat-meltable particles that can be fused by heat include waxes, acrylic resins, ionomer resins, vinyl acetate resins, vinyl chloride resins, synthetic rubbers, polyurethane resins, polyester resins, fluorine resins, silicone resins, etc. And those obtained from latex or emulsion dispersed in water.

Among these, those having a melting point of 70 to 180 ° C. are preferable, and the hydrophilic component of the surface energy is preferably 100 μN / cm ² or less. When the melting point is lower than this temperature, the performance during storage tends to deteriorate, and when it is higher than this temperature, the image strength cannot be obtained and the printing durability tends to deteriorate. Further, when the surface energy is within this range, the ink deposition property of the image portion is improved. In this respect, waxes, acrylic resins, and synthetic rubbers are particularly preferable as the hot-melt material.

  Examples of 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, candelilla 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. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups.

  A hydrophilic binder is added to the image forming layer containing heat-fusible particles that can be fused by heat in order to give the film-forming property of the image-forming layer within a range that does not impair the fusing property of the particles during laser exposure. You may make it contain.

  Usable hydrophilic binders (binders) include, for example, polyvinyl alcohol, poly (meth) acrylic acid, poly (meth) acrylamide, polyhydroxyethyl (meth) acrylate, polyvinyl methyl ether, or natural binders such as gelatin, Examples include polysaccharides such as dextran, pullulan, cellulose, gum arabic, and arginic acid. Further, the hydrophilic binder may be a water-insoluble, alkali-soluble or swellable resin having a phenolic hydroxy group and / or a carboxyl group. Various surfactants and colloidal silica can also be used.

  As a substance that exhibits lipophilicity by heat, a hot-melting substance having a melting point of 70 to 180 ° C. can be used. As waxes, carnauba wax, beeswax, whale wax, wood wax, jojoba oil, lanolin, ozokerite, paraffin wax Natural wax such as montan wax, candelilla wax, ceresin wax, microcrystalline wax, rice wax, polyethylene wax, Fischer-Tropsch wax, montan wax derivative, paraffin wax derivative, microcrystalline wax derivative, higher fatty acid, etc. Examples of resins include those obtained by copolymerizing one or more of methyl methacrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, styrene, and the like. Ene, polyisoprene, polychloroprene, styrene-butadiene copolymer, acrylic ester-butadiene copolymer, methacrylic ester-butadiene copolymer, isobutylene-isoprene copolymer, acrylonitrile-butadiene copolymer, acrylonitrile- Examples include isoprene copolymers and styrene-isoprene copolymers. In addition, ionomer resins, vinyl acetate resins, vinyl chloride resins, polyurethane resins, polyester resins, fluorine resins, silicone resins, and the like can be used. These lipophilic agents are preferably used in the form of an aqueous dispersion in terms of ease of coating.

  As another embodiment, there can be mentioned a thermal cross-linking agent covered with a thermally destructible hydrophilic coating material, and a thermal cross-linking agent in which a functional group is blocked by a protecting group dissociated by heat. These thermal crosslinking agents are described as lipophilic components microencapsulated in JP-A Nos. 7-1849, 7-1850, 9-311443, 10-6468, and 10-111168.

[Hydrophilic layer]
The hydrophilic layer according to the present invention is defined as a layer that can take in more water when an emulsified solution of water and ink arrives during printing.

  In the present invention, other layers may be formed between the support and the hydrophilic layer. For example, there are an undercoat layer that improves the adhesion of the hydrophilic layer, a swell forming layer that imparts a gentle roughness at a long wavelength, and a cushion layer that relieves stress applied to the hydrophilic layer. Any one of these layers may contain a photothermal conversion material.

[Preparation of lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention can be produced by providing an image forming layer on the above-mentioned support.

  The image-forming layer is prepared by kneading a binder resin and a colorant, and if necessary, a lubricant, a dispersant, an antistatic agent, a filler, a filler, and a solvent with a solvent to prepare a high-concentration image-forming layer composition, This can be diluted to form a photosensitive layer-forming composition for coating, which can be formed by coating and drying on a support.

  The organic solvent used in the coating material for forming the image forming layer is not particularly limited as long as it can dissolve or disperse the above composition and the metal ion complex dye. For example, alcohols (ethanol, propanol, etc.), Cellosolves (methyl cellosolve, ethyl cellosolve), aromatics (toluene, xylene, chlorobenzene, etc.), ketones (acetone, methyl ethyl ketone, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, dioxane) Etc.), halogen solvents (chloroform, dichlorobenzene, etc.), amide solvents (for example, dimethylformamide, N-methylpyrrolidone, etc.) and the like can be used. In addition, the kneading dispersion of the colorant layer components is a two roll mill, a three roll mill, a ball mill, a pebble mill, a cobol mill, a tron mill, a sand mill, a sand grinder, a Sqgvari attritor, a high speed impeller disperser, a high speed stone mill, a high speed impact mill, Dispers, high-speed mixers, homogenizers, ultrasonic dispersers, open kneaders, continuous kneaders, and the like can be used.

  The formation of the image forming layer on the support can be performed by applying and drying, for example, with an extrusion type extrusion coater. In order to increase the hardness of the surface of the photosensitive layer in order to obtain a high-resolution image, the surface is formed. Calendar processing may be performed.

[Printing method and image exposure]
As the exposure light source for forming an image on the lithographic printing plate precursor according to the invention, any light source capable of being sensitive to a metal ion complex dye can be used without particular limitation. Among them, in order to obtain a high resolution, an electromagnetic wave whose energy application area can be narrowed down, particularly an ultraviolet ray having a wavelength of 1 nm to 1 mm, a visible ray, and an infrared ray are preferable. As a light source capable of applying such light energy, for example, a laser, Light emitting diodes, xenon flash lamps, halogen lamps, carbon arc lamps, metal halide lamps, tungsten lamps, quartz mercury lamps, high pressure mercury lamps and the like can be mentioned. The energy applied at this time can be selected and used in a timely manner by adjusting the exposure distance, time, and intensity depending on the type of image forming material.

Laser light sources used in the printing method of the present invention are generally well-known solid lasers such as ruby laser, YAG laser, and glass laser; He-Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser Gas lasers such as He-Cd laser, N ₂ laser, excimer laser; semiconductor lasers such as InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, GaSb laser; chemical laser, dye laser, etc. Among these, in order to efficiently cause ablation, a laser having a wavelength of 600 to 1200 nm is preferable in terms of sensitivity because it can convert light energy into heat energy.

  The printing method of the present invention is characterized in that printing is performed without performing development processing after laser exposure based on image information.

[On-machine development]
The on-press development in the present invention has the following contents.

  A method for removing an unexposed portion of an image forming layer of a lithographic printing plate precursor by mounting the exposed lithographic printing plate precursor on a cylinder of a printing press and supplying dampening water and ink while rotating the cylinder. It is.

  In other words, the lithographic printing plate precursor is exposed and then mounted on a printing machine as it is, and the development process is completed in a normal printing process.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to these. Unless otherwise specified, the following “part” represents “part by mass”, and “%” represents “% by mass”.

[Example 1]
<Production of support>
Using terephthalic acid and ethylene glycol, PET (polyethylene terephthalate) having IV (inherent viscosity) = 0.66 (measured at 25 ° C. in phenol / tetrachloroethane = 6/4 (mass ratio)) was obtained according to a conventional method.

  This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and rapidly cooled on a cooling drum at 50 ° C. to prepare an unstretched film. The stretching temperature was stretched longitudinally by 1.3 times at 102 ° C. in the former stage stretching and 2.6 times at the latter stage stretching at 110 ° C. Then, it was stretched 4.5 times at 120 ° C. with a tenter. Thereafter, after heat setting at 240 ° C. for 20 seconds (average film thickness after heat setting was 175 μm), the film was relaxed by 4% in the lateral direction at the same temperature.

  Thereafter, the chuck portion of the tenter was slit, knurled at both ends, cooled to 40 ° C. and wound at 4.8 kg / m. In this way, a biaxially stretched PET film having a thickness of 190 μm was obtained. The biaxially stretched PET film had a Tg of 79 ° C. The width of the obtained PET film (film forming width) was 2.5 m. Further, the thickness distribution of the obtained support was 3%.

《Preparation of underdrawn support》
A corona discharge treatment of 8 W / m ² · min is applied to both surfaces of the support film obtained above, and then the following undercoat coating solution a is applied to one surface so as to have a dry film thickness of 0.8 μm. After the coating, the undercoat coating solution b was applied to a dry film thickness of 0.1 μm while performing corona discharge treatment (8 W / m ² · min), and each was dried at 180 ° C. for 4 minutes (undercoated surface) A). Also, after coating the following undercoating liquid c on the opposite surface so as to have a dry film thickness of 0.8 μm, the undercoating liquid d is applied to the dry film while performing corona discharge treatment (8 W / m ² · min). The film was applied to a thickness of 1.0 μm and dried at 180 ° C. for 4 minutes (undercoating surface B). The surface resistance of the undercoat surface B after coating at 25 ° C. and 25% RH was 10 ⁸ Ω / cm.

  Plasma treatment was performed on the surface of each undercoat layer under the following plasma treatment conditions.

Subbing coating solution a;
Styrene / glycidyl methacrylate / butyl acrylate = 60/39/1 terpolymer copolymer latex (Tg = 75 ° C.) (solid content basis) 6.3%
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 terpolymer latex 1.6%
Anionic surfactant S-1 0.1%
Water 92.0%
Subbing coating solution b;
Gelatin 1.0%
Anionic surfactant S-1 0.05%
Hardener H-1 0.02%
Matting agent (silica, average particle size 3.5 μm) 0.02%
Antifungal agent F-1 0.01%
Water 98.9%

Subbing coating solution c;
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 terpolymer latex (based on solid content) 0.4%
Styrene / glycidyl methacrylate / butyl acrylate / acetoacetoxyethyl methacrylate = 39/40/20/1 quaternary copolymer latex 7.6%
Anionic surfactant S-1 0.1%
Water 91.9%
Subbing coating solution d;
Conductive composition of component d-1 / component d-2 / component d-3 = 66/31/1 6.4%
Hardener H-2 0.7%
Anionic surfactant S-1 0.07%
Matting agent (silica average particle size 3.5 μm) 0.03%
Water 93.4%
Component d-1
Anionic polymer compound component d-2 comprising a copolymer of sodium styrenesulfonate / maleic acid = 50/50
Three-component copolymer latex component d-3 comprising styrene / glycidyl methacrylate / butyl acrylate = 40/40/20
Polymeric activator comprising styrene / sodium isoprenesulfonate = 80/20

Plasma processing conditions Using a batch type atmospheric pressure plasma processing apparatus (AP-I-H-340, manufactured by EC Chemical Co., Ltd.), a high frequency output is 4.5 kW, a frequency is 5 kHz, a processing time is 5 seconds, and a gas condition is argon. The plasma treatment was performed at a volume ratio of nitrogen and hydrogen of 90% and 5%, respectively.

Heat treatment conditions The support after slitting to a width of 1.25 m was subjected to low tension heat treatment at 180 ° C. for 1 minute at a tension of 2 hPa.

  The following coating solutions were sequentially provided on the underside A of the polyester film.

  The coating solution was applied using an OSG wireless bar so as to have a dry film thickness of 3.0 μm.

First hydrophilic layer coating solution Snowtex-XS (Nissan Chemical Industries average particle size 0.005 μm) 9.62 parts Snowtex-ZL (Nissan Chemical Industries average particle size 0.085 μm) 0.6 parts Shilton JC -40 (Mizusawa Chemical Co., Ltd. average particle size 4.0 μm) 2.22 parts Optobead 6500S (Nissan Chemical Industries Co., Ltd., coated particle average particle size 6.5 μm) 3 parts Carboxymethylcellulose sodium (Kanto Chemical Co., Ltd.) 12 parts Mineral colloid MO (manufactured by Wilber Ellis) 0.22 parts MF-4500 black (photothermal conversion material manufactured by Dainichi Seika Kogyo Co., Ltd.) 4.0 parts trisodium phosphate, 12 water (manufactured by Kanto Chemical Co., Ltd.) 0.06 Part FZ-2161 (manufactured by Nihon Unicar) 0.16 parts Pure water 80 parts OSG Application was performed using a wireless bar.

Second hydrophilic layer coating solution Snowtex-S (Nissan Chemical Industries average particle size 0.009 μm) 1.56 parts Snowtex-PSM (Nissan Chemical Industries average particle size 0.095 μm)
2.34 parts Shilton JC-20 (Mizusawa Chemical Industries average particle size 1.5 μm) 1.2 parts AMT-08 (Mizusawa Chemical Industries average particle size 0.95 μm) 3.6 parts MP-4540 (Nissan 1.85 parts carboxymethylcellulose sodium (manufactured by Kanto Chemical Co.) 0.12 parts mineral colloid MO (manufactured by Wilber Ellis) 0.24 parts MF-4500 black (Daiichi Seika Kogyo Co., Ltd.) 1.08 parts Trisodium phosphate, 12 hydrate (manufactured by Kanto Chemical Co., Ltd.) 0.06 parts Pure water 88 parts The obtained hydrophilic layer laminated product has a dry film thickness of 0.55 (g / g). m ² ) The following image forming layer application was performed using a wireless bar coating apparatus manufactured by OSG Corporation.

Image forming layer HI-DISPER A-206 (Gifu Shellac Manufacturing Co., Ltd.)
Heat-meltable particle average particle size 0.5 μm 2.375 parts DL-522 (Nippon Shokubai Co., Ltd. average molecular weight 170.000) 0.7125 parts HI-DISPER A118 (Gifu Shellac Manufacturing Co., Ltd.)
Average particle diameter of heat-fusible particles 0.3 μm 6.4125 parts Pure water 90.5 parts At this time, the image forming layer coating solution temperature was 20 ° C. and A = 11 mPa · s (B type viscometer manufactured by Tokyo Keiki Seisakusho Co., Ltd.) Measured at

  This sample is designated as Sample No. 101. Similarly, the part shown in Table 2 was changed, and sample No. 102-110 were produced and the following evaluation was performed about these.

[Performance evaluation]
(Coating defects)
The number of omissions per 1 m ² of the sample 100 m and 2000 m after coating was counted.

  The larger the number of coating defects, the worse.

(Omitted size)
The size (μm) of the largest missing coating failure per sample m ² after 100 m and 2000 m after coating was measured.

(Vertical stripes (application direction stripes))
The rank per sample m ² after 100 m and 2000 m after coating was evaluated as follows.

5; No occurrence 4; Little occurrence, no actual damage 3; Little occurrence, actual damage concern level 2; Occurrence, actual damage 1; Multiple occurrence, actual damage The following evaluation was also performed.

(Exposure and printing of lithographic printing plate precursor)
Using the obtained lithographic printing plate precursor, a semiconductor laser light source (light emission wavelength: 830 nm, spot size: 10 μm, resolution is 2000 dpi in both the scanning direction and the sub-scanning direction), a 175-line equivalent 50% dot image and a solid image, The exposure was performed with the irradiation energy amount on the image surface being 250 mJ / cm ² while changing the scanning speed.

  In addition, dpi represents the number of dots per 2.54 cm.

  The exposed lithographic printing plate precursor is attached to a Heidel GTO printing machine without developing, and a SEU-3 (manufactured by Konica) 45-fold water diluted solution as an etchant, and a high echo (manufactured by Toyo Ink Co., Ltd.) as ink. The printing was performed using high-quality paper as printing paper.

  Printing was performed in an environment of 23 ° C. and 48% RH.

(Printed quality)
Samples 100 m and 2000 m after application were evaluated below.

  The finished quality of the 30th sheet after the start of printing was visually evaluated at the following rank.

5 ... Good quality 4 ... Slightly inferior, but no problem in use 3 ... Slightly inferior, but usable level 2 ... Poor quality, Possibility of serious harm 1 ... Poor quality, Unusable (Print life)
Samples 100 m and 2000 m after coating were evaluated as follows. The number of prints where 50% halftone dots were not reproduced was visually evaluated. The larger the number, the higher the printing durability and the better. Samples with different temperatures were also evaluated.

  As can be seen from Table 1, when the present invention is satisfied, a lithographic printing plate precursor having sufficiently stable coating properties and good performance is obtained.

[Example 2]
After using the same support (width 1130 mm) as in Example 1 and providing the same first and second hydrophilic layers, using the bar, the image forming layer as in Example 1 under the conditions shown in Table 2 Application was performed.

  The viscosity of the image forming layer coating solution at this time was 18 mPa · s (measured with a B-type viscometer manufactured by Tokyo Keiki Seisakusho Co., Ltd.).

  As can be seen from Table 2, if the present invention is satisfied, an original plate for lithographic printing having a sufficiently stable coating property and good performance can be obtained even when the coating speed and the bar rotation speed are changed.

Claims (4)

In the method for producing an original plate for lithographic printing comprising, on a support, at least a hydrophilic layer containing particulate matter and having irregularities on the hydrophilic layer surface, and an image forming layer in this order,
In order to form an image forming layer on a support that has been continuously coated with a hydrophilic layer, after applying an excessive amount of the coating liquid adjusted to the following viscosity, A method for producing an original plate for lithographic printing, wherein the coating is performed while scraping off.
Viscosity adjustment of coating solution: When the viscosity of the coating solution at 20 ° C. is A (mPa · s), the coating solution temperature is adjusted to fall within the range of A ± 0.40A. In the method for producing an original plate for lithographic printing comprising, on a support, at least a hydrophilic layer containing particulate matter and having irregularities on the hydrophilic layer surface, and an image forming layer in this order,
In order to form an image forming layer on a support that has been coated with a hydrophilic layer that has been continuously conveyed, after applying an excessive amount of the coating solution, the excess coating solution is applied using a bar under the following conditions. A method for producing an original plate for lithographic printing, wherein the coating is performed while scraping off.
Scraping conditions: If the coating width is T1 (mm) and the bar length is T2 (mm), a bar that falls within the range of 1.20T1 ≦ T2 is used. A lithographic printing plate precursor produced by the method for producing a lithographic printing plate precursor according to claim 1 or 2. A printing method comprising: printing the original plate for lithographic printing according to claim 3 by laser exposure based on image information and performing on-press development processing.