JPH11143136A - Manufacture of planographic printing plate and sheet for manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a planographic printing plate using an electrophotographic method by which an image with high quality is inexpensively provided and a sheet for manufacturing the planographic printing plate advantageously used for the method. SOLUTION: A sheet for manufacturing a planographic printing plate 1 which is formed by laminating a conductive layer 3 consisting of a conductive component essentially consisting of stannic oxide in which a hetero-atom is doped and a binder and a photoconductive layer 5 consisting of zinc oxide and the binder on a non- conductive supporting body 2 in this order and whose the whole volume resistivity is within the range of 1.0×10<6> to 1.0×10<9> Ω.cm is used for this manufacturing method. Besides, this method is constituted of a process that the layer 5 is electrified by executing negative corona discharge on the surface of the sheet 1 on the layer 5 side while bringing a ground-potential conductive body into contact with the surface of on the supporting body 2 side, a process that a latent image is formed on the surface of the layer 5 by irradiating light on the surface of the electrified layer 5 like an image, a process that the latent image is developed by imparting a lipophilic toner on the surface of the layer 5 having the latent image to form a lipophilic toner image and a process for hydrophilic-processing of a non-image forming part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lithographic printing plate utilizing electrophotography and a sheet for producing a lithographic printing plate which is advantageously used in the method.

[0002]

2. Description of the Related Art As a method for producing a lithographic printing plate utilizing electrophotography, a lithographic printing plate production sheet (original plate) comprising a conductive support and a photoconductive layer provided on the support. Using a corona discharge on both surfaces to charge the photoconductive layer, forming an electrostatic latent image by imagewise exposing the photoconductive layer side surface of the master, and applying lipophilic toner to the photoconductive layer surface. 2. Description of the Related Art A method comprising a step of adhering, developing and fixing, and a step of desensitizing (hydrophilizing) a non-image portion on the surface of a photoconductive layer has been widely known. The planographic printing plate obtained by this method can be used for offset printing and the like. In this charging step, a negative corona discharger is disposed on the photoconductive layer side of the original plate, and a positive corona discharger is disposed on the support side, and discharge (so-called double corona discharge) is performed simultaneously. The upper and lower sides of the photoconductive layer are charged to-and +, respectively.

In the printing plate manufacturing (plate making) method using the double corona discharge, if the conductivity of the support of the lithographic printing plate manufacturing sheet is low, the discharge phenomenon does not occur well during the charging treatment, and as a result, the image is not printed. There is a problem that the quality tends to deteriorate. Therefore, the conductive support preferably has a volume resistivity of 1 × 10 ¹⁰ Ω · cm or less, and is prepared by coating polyethylene or the like containing a conductive filler on one or both sides of paper or a resin film. (Conductive laminating paper, described in JP-A-59-64395), or one obtained by bonding metal foils such as aluminum, zinc, and copper (metal foil laminating paper;
No. 12432). However, these conductive supports have drawbacks such as insufficient conductivity and difficulty in producing a high-quality lithographic printing plate, or high production cost.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a high-quality lithographic printing plate which is free from fogging and charging unevenness in an image portion and which can provide a sharp printed image is formed by electrophotography. It is an object of the present invention to provide a manufacturing method and a lithographic printing plate manufacturing sheet that can be advantageously used in the method.

[0005]

SUMMARY OF THE INVENTION The present invention firstly provides a conductive layer comprising a conductive component mainly composed of tin dioxide doped with a different atom and a binder, and a photoconductive layer comprising zinc oxide and a binder. The layers are laminated in this order on a non-conductive support, and the volume resistivity of the conductive layer is 1.0 ×
Using a sheet for producing a lithographic printing plate in the range of 10 ^{6 to} 1.0 × 10 ⁹ Ω · cm, a negative corona is applied to the surface of the photoconductive layer side while a conductor at the ground potential is brought into contact with the surface of the support side. Charging the photoconductive layer by performing a discharge, forming a latent image on the surface of the photoconductive layer by irradiating the charged photoconductive layer with light in an image-wise manner, a photoconductive layer having a latent image Forming a lipophilic toner image by applying a lipophilic toner to the surface of the lithographic printing plate, and subjecting the non-image portion to a hydrophilic treatment. . Secondly, the present invention provides a method in which a conductive layer composed of a conductive component mainly composed of tin dioxide doped with a different atom and a binder and a photoconductive layer composed of zinc oxide and a binder are formed on a non-conductive support. They are laminated in this order, and the volume resistivity of the conductive layer is 1.0
It is a lithographic printing plate manufacturing sheet in the range of × 10 ^{6 to} 1.0 × 10 ⁹ Ω · cm.

A method of manufacturing a lithographic printing plate utilizing electrophotography according to the present invention is characterized in that a lithographic printing plate manufacturing sheet having a specific structure is used, and a single corona discharge is used in the charging process. Is the way.

Preferred embodiments of the sheet for producing a lithographic printing plate used in the method of the present invention are described below. (1) The sheet for producing a lithographic printing plate as described above, wherein the tin dioxide doped with a different kind of atom is tin dioxide doped with antimony. (2) Volume resistivity of the conductive layer is 1.0 × 10 ^{6 to} 1.0
The sheet for producing a lithographic printing plate as described above in the range of × 10 ⁸ Ω · cm. (3) The lithographic printing plate-producing sheet described above, wherein at least a part of the side surface of the support is provided with a fringe containing a conductive substance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lithographic printing plate manufacturing sheet used in a lithographic printing plate manufacturing method utilizing electrophotography according to the present invention will be described. The lithographic printing plate manufacturing sheet of the present invention is basically formed on a non-conductive support, a conductive layer comprising a conductive component mainly composed of tin dioxide doped with foreign atoms and a binder, and zinc oxide. And a binder are formed in this order.
However, the lithographic printing plate manufacturing sheet is not limited to this basic configuration, and may be provided with various intermediate layers and a back surface layer as described later.

FIG. 1 shows a typical example of the structure of a sheet for producing a lithographic printing plate according to the present invention. FIG. 1 shows a non-conductive support 2,
A lithographic printing plate manufacturing sheet 1 according to the present invention, in which a conductive layer 3, an intermediate layer (blocking layer) 4, and a photoconductive layer 5 are laminated in this order, and further, an edge sticking 6 is provided on a side surface of the laminate. .

Hereinafter, the method for producing a sheet for producing a lithographic printing plate of the present invention will be described in detail. As the non-conductive support, for example, paper or a resin film is used. Examples of resin materials for the resin film include polyamide, polyolefin, ethyl acrylate-ethyl methacrylate copolymer, acrylonitrile-methyl methacrylate copolymer, amylose acetate, styrene-butadiene copolymer, polycarbonate, and polyformic acid. Vinyl, poly-p
-Chlorostyrene, polyvinyl acetate, polydimethylsiloxane, polystyrene, polyethyl acrylate, polyacrylonitrile, polyacenaphthylene, 1,4-polyisoprene, poly-p-isopropylstyrene, polyethylene terephthalate, polyethylene naphthalate, polyethylene, Polyvinyl chloride, polyoxymethylene, polypropylene oxide, polybutyl methacrylate, isobutyl polymethacrylate, 2-ethylbutyl polymethacrylate, n-butyl polymethacrylate, polymethyl methacrylate, poly-n-lauryl polymethacrylate, Poly
α-methylstyrene, poly-p-methylstyrene, poly-o-methoxystyrene, poly-p-methoxystyrene, polytetrahydrofuran, polyvinyl alcohol,
Poly-N-vinylcarbazole, poly-1-vinylnaphthalene, poly-2-vinylnaphthalene, polyvinylbiphenyl, poly-2-vinylpyridine, polyphenylene oxide, polybutadiene, polybutene, polybutene oxide, polypropylene, and polymers thereof are listed. Can be. Of these, polyethylene terephthalate (PETP) films are most preferred. Further, a laminated paper obtained by applying and processing the above resin on one or both sides of the paper may be used, and a polyethylene laminated paper laminated on both sides is particularly preferable.

The non-conductive support used in the sheet for producing a lithographic printing plate of the present invention has a volume resistivity of 1 × 10 ¹⁰ Ω · cm.
It is preferably larger than 1 × 10 ¹¹
Ω · cm or more. The upper limit is not particularly limited, but is usually 1 × 10 ¹⁷ Ω · cm or less. By making the volume resistivity of the support larger than 1 × 10 ¹⁰ Ω · cm, a discharge phenomenon is likely to occur in the atmosphere between the conductive layer and the conductor during corona discharge from the photoconductive layer side in the plate making process. And can be charged quickly. That is, the charging time can be reduced.

The thickness of the support is usually 75 to 200 μm.
, Preferably in the range of 120 to 180 μm,
Particularly preferably, it is in the range of 140 to 160 μm. If the thickness of the support is too large, a strong discharge breakdown phenomenon is likely to occur in a part of the support during corona discharge, and the photoconductive layer may be melted and burned out. On the other hand, if the thickness of the support is too thin, the strength, durability and the like required for the support will be insufficient.

When a laminated paper is used as a support, the thickness of the paper itself is usually in the range of 50 to 150 μm, and the thickness of the laminated resin is in the range of 15 to 30 μm. In order to improve the adhesive strength between the paper and the laminating resin, an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ethylene-methacrylate copolymer, an ethylene-acryl Applying polyethylene derivatives such as acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylonitrile-acrylic acid copolymer and ethylene-acrylonitrile-methacrylic acid copolymer, or corona discharge treatment of paper surface You may keep it. In addition, Japanese Unexamined Patent Publication No.
-24126, 52-36176, 52-12
No.1683, No.53-2612, No.54-11133
No. 1 and JP-B-51-25337 can be subjected to the surface treatment described above.

A conductive layer is provided on the support. The conductive layer is a layer composed of a binder containing a conductive component whose main component is tin dioxide (SnO ₂ ) doped with different atoms.

Examples of conductive components which can be used in combination with tin dioxide doped with foreign atoms include metals such as aluminum, zinc, silver, iron, copper, titanium, manganese, cobalt and palladium, or oxides thereof. Things can be mentioned. In addition, a conductive substance such as carbon black or graphite can be used in combination. Representative examples of the heteroatoms doped into tin dioxide include antimony atoms, and the doping amount is usually
It is in the range of 0.1 to 10 mol%. Tin dioxide doped with foreign atoms is 50% by weight based on the whole conductive component.
Used in the above ratio, preferably 70 to 100% by weight
Used in the ratio of

Examples of the binder include proteins such as gelatin, colloidal albumin and casein; cellulose compounds such as carboxymethylcellulose, hydroxyethylcellulose, diacetylcellulose and triacetylcellulose; sugar derivatives such as agar, sodium alginate and starch derivatives; , Shellac and the like and derivatives thereof. Further, the resins listed above as the material of the support can also be used.

The conductive layer is formed by dispersing the above-mentioned conductive metal particles mainly composed of tin dioxide doped with different kinds of atoms in a solution obtained by dissolving a binder in an appropriate solvent to prepare a coating solution. The solution can be formed by applying and drying the liquid on the surface of the support. The conductive component mainly composed of tin dioxide doped with foreign atoms is generally added in the range of 25 to 250% by weight based on the binder. In order to enhance the dispersibility of these metal components, various additives such as a surfactant may be further added to the coating solution.

The coating on the support is preferably performed by a bar coating method, a roll coating method such as a gravure method or a reverse method, or a coating method such as a doctor knife method, an air knife method or a nozzle coating method.
Alternatively, a conductive film separately formed by coating on a temporary support or the like may be adhered to the surface of the support using an adhesive. The thickness of the conductive layer varies depending on the type and amount of the conductive component and the type and amount of the binder, but is usually in the range of 0.5 to 10 μm, preferably 2 to 5 μm.
In the range.

As described above, by forming the conductive layer as a layer comprising a binder containing a conductive component, the conductive layer can be easily formed on a support by coating or the like, and the volume resistivity can be adjusted. Furthermore, the handling of the manufactured lithographic printing plate manufacturing sheet becomes easy. The surface of the support on the side where the conductive layer is provided may be previously subjected to corona discharge treatment or chemical pretreatment in order to enhance the adhesion between the support and the conductive layer, or An intermediate layer such as an undercoat layer may be provided.

Between the conductive layer and the photoconductive layer provided thereon, a blocking layer is provided for the purpose of preventing charge and / or electron movement, improving charging efficiency, and preventing charging unevenness and the like. Is preferred. As the material of the blocking layer, a material which can form a uniform thin film and has the above-described effects can be appropriately selected from the resins described as the material of the support. Preferred among the resins are polymethyl methacrylate and polyacrylonitrile. The blocking layer can be formed, for example, by dissolving these resins in an appropriate solvent to prepare a coating solution, applying the coating solution to the surface of the conductive layer not facing the support, and drying. . Alternatively, these resin films may be joined using an adhesive or the like.

The blocking layer has a volume resistivity of 1 × 1.
It is preferably at least 0 ¹⁰ Ω · cm, particularly preferably at least 1 × 10 ¹¹ Ω · cm. The upper limit is not particularly limited, but is usually 1 × 10 ¹⁴ Ω · cm or less. The layer thickness of the blocking layer is usually in the range from 0.2 to 2 μm.

On this conductive layer or the blocking layer, a photoconductive layer made of a binder containing zinc oxide (ZnO) dispersed therein is provided. Usually, zinc oxide having a particle size in the range of 0.1 to 0.5 μm is used. There is no particular limitation on the binder, and a binder having good mechanical and electrical properties that is generally used can be used. Examples of such binders include polystyrene, polyacrylates, polymethacrylates, polyvinyl acetate, polyvinyl chloride, polyvinyl butyral and derivatives thereof, polyester resins, acrylic resins, epoxy resins, and silicone resins. be able to. Of these, acrylic resins are preferred. The mixing ratio between zinc oxide and the binder is usually 3: 1 to 2 by weight.
It is in the range of 0: 1. The photoconductive layer can be formed on the conductive layer or the blocking layer by coating or using an adhesive or the like as in the case of the conductive layer.
Usually, the coating amount is in the range of 15 to 30 g / m ² , and the thickness of the formed photoconductive layer is in the range of 5 to 30 μm.

Further, a back coat layer may be provided on the surface of the support opposite to the conductive layer for the purpose of preventing slippage and controlling conductivity. The back coat layer is a layer made of a polymer binder containing a conductive agent such as carbon black and particles (particle diameter: about 0.1 to 1 μm) for controlling the rigidity in a uniform dispersion.

Examples of the polymer substance used for the binder of the back coat layer include polyethylene, polybutadiene, polyacrylate, polymethacrylate, amylose polyacetate, nylon, polycarbonate, polyvinyl formate, polyvinyl acetate, and polyvinyl acetate. Acenaphthylene, polyisoprene, polyethylene terephthalate,
Examples thereof include those obtained by curing polyvinyl chloride, polyoxyethylene, polypropylene oxide, polytetrahydrofuran, polyvinyl alcohol, polyphenylene oxide, polypropylene, copolymers thereof, and gelatin and polyvinyl alcohol.

Further, on the side surface of the support of the sheet for producing a lithographic printing plate of the present invention thus produced, a discharge phenomenon is apt to occur at the time of charging treatment to prevent the occurrence of uneven charging or the like. Therefore, it is preferable to provide an edge paste containing a conductive substance (perform edge processing). The border may be provided on the entire side surface of the support, or may be provided on a part of the side surface of the support. However, it is necessary to provide this edge bonding so as to electrically connect the front side and the back side of the support, and a volume resistivity of 1 × 10 ³ to 1 × 10 ⁷ is preferable.

Examples of the conductive material used for edge bonding include:
For example, carbon black, colloidal silica, colloidal alumina, aluminum, titanium, manganese, cobalt, palladium and other metals, and chlorides thereof,
Oxides and bromides can be mentioned. The edge paste is prepared by dispersing the particles of the conductive substance in a solution of a binder appropriately selected from the materials of the support and the material described as the binder of the conductive layer to prepare a coating solution. (When a back coat layer is provided on the surface of the support, it can be formed by coating and drying on the side surface of the support and the back coat layer). The thickness of the rim application is usually in the range of 50 to 200 μm. This bordering may be provided only on the side surface of the support, or may be provided on the side surface of the entire lithographic printing plate manufacturing sheet including the support.

Next, the method for producing a lithographic printing plate (plate making method) of the present invention will be described with reference to FIG. 2 by taking as an example the case of using the lithographic printing plate production sheet shown in FIG. .

FIG. 2 is a conceptual diagram showing an apparatus used in the method for producing a lithographic printing plate from a lithographic printing plate producing sheet of the present invention. In FIG.
1, a charging section 12 by single corona discharge, an exposure section 13, and a development / fixing section 14.

In the plate making apparatus shown in FIG. 2, a lithographic printing plate manufacturing sheet (hereinafter, referred to as a master) 1 is first supplied to a sheet feeding section 1.
From No. 1 is supplied to the charging processing unit 12 by the transport means. In the charging section 12, a negative corona discharger 15 disposed on the photoconductive layer 5 side of the master 1 and a conductor 16 having a ground potential disposed on the support 2 side of the master 1 and grounded by the conductor 17 are provided. The master 1 is charged (ie, a single corona charging process is performed). Conductor 1
Numeral 6 is in contact with the support 2 of the master 1 and functions as a ground electrode and also functions as a transport guide.

At this time, the volume resistivity of the support 2 is 1 × 1
Since it is larger than 0 ¹⁰ Ω · cm, the conductive layer 3 and the conductor 16 are electrically close to each other in an electrically insulated state.
Operates, the air discharge phenomenon occurs because the distance from the conductor 16 to the conductive layer 3 is short corresponding to the thickness of the support 2, whereby the master 1 has − and + above and below the photoconductive layer 5. To be charged. Further, when the lithographic printing plate manufacturing sheet is provided with the conductive rim 6, the conductive layer 3 and the conductor 16 are electrically connected, so that a discharge phenomenon occurs more easily, and as a result, the sheet is conveyed. The speed can be increased, and uneven charging is reduced.

The conductor 16 has a volume resistivity of 1 × 1.
0 ³ Ω · cm or less, for example, iron,
Metals such as copper and aluminum, alloys such as stainless steel and the like, which have been subjected to surface treatment such as nickel and chromium, carbon resins, and resin materials containing a conductive material can be used. The thickness of the conductor is appropriately determined depending on its material, the structure of the plate making apparatus, and the like, but is usually in the range of 0.1 to 5 mm. Also, its dimensions
It can be determined according to the dimensions of the corona discharger (charger) and the master.

The voltage applied for corona discharge is -4 to-
It is preferably in the range of 10 KV, and particularly preferably in the range of -5.5 to -6.5 KV. The speed at which the master passes under the corona discharger is 1 to 50 cm /
It is preferably in the range of seconds, particularly preferably 5 to 2 seconds.
The range is 0 cm / sec.

Next, the master 1 is transported to the exposure unit 13 by the guide roller 18. In the exposure section 13, the master 1 is imagewise exposed by an exposure image such as laser light or incandescent light converged by the lens 19. As a result, the charge in the exposed region of the photoconductive layer 5 disappears, and the charge remains only in the non-exposed region. That is, an electrostatic latent image is formed on the photoconductive layer 5.

Next, the exposed master 1 is conveyed to the developing / fixing section 14 by the guide roller 20.
In the developing / fixing section 14, the lipophilic toner adheres to the non-exposed area, which is the remaining charge portion of the master 1, and is developed (preferably wet development) by the developing / fixing device 21, and the lipophilic toner is heated and fixed. Form a lipophilic layer. The plate making apparatus that can be used in the method for producing a lithographic printing plate of the present invention is not limited to the apparatus shown in FIG.
Any device may be used as long as it charges a lithographic printing plate manufacturing sheet by single corona discharge in the charging section.

The developed and fixed lithographic printing plate production sheet is further subjected to a desensitization treatment (hydrophilization treatment). This hydrophilization treatment is a treatment for chemically treating the surface of the photoconductive layer layer on which the lipophilic toner layer is not formed to make the photoconductive layer layer hydrophilic. Cyanide-free treatment liquid containing ferrocyanide salt, ferricyan salt as a main component, ammine cobalt complex, phytic acid and its derivatives, guanidine derivative as a main component, forming chelate with zinc ions Examples thereof include a treatment liquid containing an inorganic acid or an organic acid as a main component and a treatment liquid containing a water-soluble polymer.

Examples of the treating solution containing a cyan compound include, for example, JP-B-44-9045 and JP-B-46-39403, JP-A-52-76101, JP-A-57-107889, and JP-A-57-107889.
What is described in each gazette of 4-117201 can be used. Examples of the processing solution containing a phytic acid compound include, for example, JP-A-53-83805 and JP-A-53-838.
No. 07, No. 53-102102, No. 53-10970
No. 1, No. 53-127003, No. 54-2803,
It is possible to use those described in each gazette of JP-A-54-44901.

Examples of the treating solution containing a metal complex compound such as a cobalt complex are described in JP-B-43-28404, JP-A-53-104301, JP-A-53-140103 and JP-A-54-18304. Can be used. Examples of the treating solution containing an inorganic acid or an organic acid include JP-B-39-13702 and JP-B-40-10.
No. 308, No. 43-28408, No. 40-26124
And those described in JP-A-51-118501 can be used.

As the guanidine compound-containing treating solution, for example, those described in JP-A-56-111695 can be used. Examples of the treatment solution containing a water-soluble polymer include, for example, JP-B-38-9665 and JP-B-39-222.
Nos. 63, 40-763, 40-2202, JP-A-49-36402, 52-126302, and 5
2-134501, 53-49506, 53-
Nos. 59502 and 53-104302 can be used.

By the hydrophilization treatment using any of the above-mentioned treatment solutions, zinc oxide in the surface layer is ionized into zinc ions, and these ions cause a chelation reaction with the chelate-forming compound in the treatment solution to cause zinc ion. Forming a chelate,
It is believed that this is deposited in the surface layer and becomes hydrophilic.

The hydrophilization (desensitization) treatment is usually performed at room temperature (15 to 35 ° C.) for 0.5 to 30 seconds. Thereafter, the lithographic printing plate manufacturing sheet is dried. Using the lithographic printing plate thus prepared, about 3000 sheets of offset printing can be performed using dampening water. Hereinafter, examples of the present invention will be described. However, the present invention is not limited by the following examples.

[0041]

Example 1 A lithographic printing plate manufacturing sheet according to the present invention (an embodiment having the structure shown in FIG. 1) by the following method.
Samples were produced. (1) Support A support was obtained by laminating polyethylene on both sides of a high-quality paper having a basis weight of 100 g / m ² by a melt extrusion method so as to have a thickness of 20 μm per side.

(2) Conductive layer After the surface of the support was subjected to a corona discharge treatment, a coating solution of the following composition I was coated with a wire bar to obtain a solid content of 0.1%.
The composition was applied so as to be ² g / m ^2, and then dried at 110 ° C. to form a conductive layer. The volume resistivity of the conductive layer is 5.
It was 9 × 10 ⁸ Ω · cm.

Composition I Antimony-doped tin dioxide 7 parts by weight Water 35 parts by weight Gelatin (aqueous solution having a solid content of 10% by weight) 8 parts by weight Methanol 100 parts by weight Non-ionic surfactant 0.02 parts by weight

(3) Blocking Layer A coating dispersion of the following composition II was applied to the surface of the conductive layer with a wire bar so that the coating amount of solids was 3 g / m ^2, and dried at 120 ° C. to form a blocking layer. Was formed.
The volume resistivity of the blocking layer is 8.2 × 10 ¹² Ω · c
m.

Composition II Styrene butadiene latex (solid content 50% by weight) 35 parts by weight Starch 1 part by weight Clay (water dispersion having a solids content of 45% by weight) 100 parts by weight Water 90 parts by weight

(4) Photoconductive layer A coating dispersion of the following composition III was applied to the surface of the blocking layer with a wire bar so that the applied amount of solids was 25 g / m ² , dried at 100 ° C., and dried at 100 ° C. ° C, 6
The photoconductive layer was formed by being left in a dark room kept at 0% RH for 24 hours.

Composition III Photoconductive zinc oxide 100 parts by weight Acrylic resin 20 parts by weight Phthalic anhydride 0.1 part by weight Toluene 125 parts by weight Rose Bengal (4% methanol solution) 4.5 parts by weight

(5) Edge application A coating dispersion of the following composition IV is sprayed on one side of the laminate comprising the support, the conductive layer, the blocking layer and the photoconductive layer so as to have a thickness of about 200 μm. After the application, drying was performed at 120 ° C. to form an edge paste, and a sample of a lithographic printing plate manufacturing sheet according to the present invention was obtained. The volume specific resistance of this edge bonding layer was 7.4 × 10 ³ Ω · cm.

Composition IV Styrene butadiene latex (solid content 50% by weight) 100 parts by weight Carbon black (particle size 20 μm) 25 parts by weight Clay (water dispersion having a solids content of 45% by weight) 100 parts by weight Water 35 parts by weight Melamine 3 parts by weight Department

Example 2 The present invention was carried out in the same manner as in Example 1 except that the content of antimony-doped tin dioxide in the coating liquid for forming a conductive layer (composition I) was changed to 15 parts by weight. A sample of a lithographic printing plate manufacturing sheet according to the above was manufactured. The volume resistivity of this conductive layer is 4.9 × 10
It was ⁷ Ω · cm.

Comparative Example 1 A comparative example was prepared in the same manner as in Example 1 except that the content of tin dioxide in the coating liquid for forming a conductive layer (composition I) was changed to 0 parts by weight. A sample of a lithographic printing plate manufacturing sheet was manufactured. The volume resistivity of the conductive layer was 4.7 × 10 ¹⁵ Ω · cm.

Comparative Example 2 In Example 1, the following composition V was used instead of the dispersion of composition I as the coating liquid for forming a conductive layer.
Using a water bar, the solids coating amount is 5
g / m ^2, and then dried at 120 ° C. to form a conductive layer, and a lithographic printing plate for comparison was prepared in the same manner as in Example 1 except that no border was provided. A sample of the production sheet was produced. The volume resistivity of this conductive layer was 3.8 × 10 ⁸ Ω · cm.

Composition IV Vinylbenzyl quaternary ammonium (20% by weight aqueous solution) 100 parts by weight Water 20 parts by weight

Example 3 (1) Support Both sides of high-quality paper having a basis weight of 100 g / m ² were impregnated with an aqueous NaCl solution to adhere to 1.3 g / m ² as a NaCl solid to obtain a support. Was. The volume resistivity of the support is 2.1
× 10 ¹¹ Ω · cm.

(2) Conductive layer The coating solution of the composition I used in Example 1 was applied to the surface of this support with a wire bar so that the solid coating amount was 0.6 g / m ^2, and then 120 ° C. To form a conductive layer.

(3) Photoconductive layer A photoconductive layer was formed on the surface of the conductive layer in the same manner as in Example 1, and a lithographic printing plate manufacturing sheet according to the present invention was manufactured.
The volume resistivity of this conductive layer was 7.2 × 10 ⁸ Ω · cm.

Comparative Example 3 In Example 3, the aqueous solution of the composition V used in the comparative example 2 was used instead of the dispersion liquid of the composition I as the coating liquid for forming the conductive layer, and the solid content applied amount was 14 g using a wire bar. / M ² after application.
A lithographic printing plate manufacturing sheet sample for comparison was produced in the same manner as in Example 3 except that the conductive layer was formed by drying at 0 ° C. The volume resistivity of this conductive layer is 6.9.
× 10 ⁸ Ω · cm.

[Evaluation Test] Each of the samples of the lithographic printing plate production sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was left under the following three types of temperature and humidity environmental conditions. Single corona charging type plate making machine (Fig. 2
See Fuji Photo Film Co., Ltd., ELP-330R
X) was used for plate making. 1) 20 ° C, 65% RH 2) 10 ° C, 30% RH 3) 30 ° C, 80% RH

Next, printing was performed using the manufactured lithographic printing plate, and the obtained image was evaluated by a fog test on a non-image portion, a charging unevenness test, and an image sharpness test.

(1) Fog test of non-image area Printed matter was measured with a Macbeth reflection densitometer, and evaluated as AA, BB, CC (CC cannot be used) in ascending order of fog in the non-image area. The results are shown in Tables 1 to 3.

(2) Charging unevenness test A solid portion of 15 cm square of the printed matter was visually observed,
The evaluation was based on the following criteria. The results are shown in Tables 1 to 3. AA: All are uniform. BB: Charge unevenness is slightly observed. CC: Charging unevenness is clearly observed.

(3) Image sharpness test A 10-point Mincho Korean "Long" character of the printed matter was visually observed and evaluated based on the following criteria. The result is
The results are shown in Tables 3 to 3. AA: Sharp and smooth in all parts of “long”. BB: Thickness and thinning are confirmed at one or more locations of “long”. CC: One or more missing “long” lines are confirmed.

[0063]

[Table 1] Table 1-20%, 65% RH non-image fog Charging unevenness Sharpness ─────────────────────────────────── Example 1 AA AA AA Example 2 AA AA AA 比較 Comparative Example 1 CC AA BB Comparative Example 2 AA AA AA ── Example 3 AA BB BB ──────────────────────── Comparative Example 3 AA BB BB ──────────────────── ───────────────

[0064]

[Table 2] 10 ° C, 30% RH non-image fog Charging unevenness Sharpness ─────────────────────────────────── Example 1 AA AA AA Example 2 AA AA AA 比較 Comparative Example 1 CC AA BB Comparative Example 2 CC AA AA ── Example 3 AA BB BB比較 Comparative Example 3 CC BB BB ──────────────────── ───────────────

[0065]

[Table 3] 30 ° C, 80% RH non-image fog Charging unevenness Sharpness ─────────────────────────────────── Example 1 AA AA AA Example 2 AA AA AA 比較 Comparative Example 1 AA CC CC Comparative Example 2 AA CC CC ── Example 3 AA BB BB比較 Comparative Example 3 AA CC CC ──────────────────── ───────────────

As is clear from the above results, Example 1
Lithographic printing manufactured using the electrophotographic method of the single corona method according to the present invention, using the lithographic printing plate manufacturing sheet having the conductive layer containing antimony-doped tin dioxide of the present invention obtained in the above-mentioned Examples 3 to 3 The plate gives a sharp image with almost no non-image fog and uneven charging even when environmental conditions such as temperature and humidity change. In particular, the lithographic printing plate production sheet of the present invention having the conductive margins obtained in Examples 1 and 2 gives an extremely high-quality image without being affected by environmental conditions such as temperature and humidity.

[0067]

According to the method of manufacturing a lithographic printing plate using the electrophotographic method by the single corona method using the lithographic printing plate manufacturing sheet of the present invention, the manufacturing cost is low and the manufacturing process is relatively simple. Thus, it becomes possible to use a lithographic printing plate manufacturing sheet which is easy to handle. And, the lithographic printing plate manufacturing sheet of the present invention is inexpensive and easy to handle, in addition to the fact that the conductive layer contains a conductive component mainly composed of tin dioxide doped with different kinds of atoms, A printed matter of stable quality which does not hinder practically any change in environmental conditions such as temperature and humidity, particularly change in humidity can be obtained.
Further, the lithographic printing plate manufacturing sheet of the present invention is provided with a conductive rim, so that high-quality (no non-image fog and non-uniform charging, which is not affected by environmental conditions such as temperature and humidity,
Image with excellent sharpness).

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of a lithographic printing plate manufacturing sheet according to the present invention.

FIG. 2 is a conceptual diagram showing an example of a lithographic printing plate manufacturing apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lithographic printing plate manufacturing sheet 2 Support 3 Conductive layer 4 Blocking layer 5 Photoconductive layer 6 Edge bonding 11 Paper feed unit 12 Charging unit 13 Exposure unit 14 Developing / fixing unit 15 Negative corona discharger 16 Conductor 17 Conductor 18, 20 guide roller 19 lens 21 developing and fixing device

Claims (6)

[Claims] 1. A conductive layer comprising a conductive component mainly composed of tin dioxide doped with a different atom and a binder, and a photoconductive layer comprising zinc oxide and a binder are formed on a non-conductive support. And the volume resistivity of the conductive layer is 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ Ω · cm.
Charging the photoconductive layer by performing a negative corona discharge on the photoconductive layer side surface while using a lithographic printing plate manufacturing sheet in the range described above and contacting a ground potential conductor with the support side surface. Forming a latent image on the surface of the photoconductive layer by imagewise irradiating light to the surface of the charged photoconductive layer; developing by applying lipophilic toner to the surface of the photoconductive layer having the latent image Forming a lipophilic toner image, and hydrophilizing the non-image area. 2. The method for producing a lithographic printing plate according to claim 1, wherein the lithographic printing plate production sheet is provided with a fringe containing a conductive substance on at least a part of the side surface of the support. 3. A conductive layer composed of a conductive component mainly composed of tin dioxide doped with a different atom and a binder and a photoconductive layer composed of zinc oxide and a binder are formed on a non-conductive support. A lithographic printing plate manufacturing sheet which is laminated in order and has a volume resistivity of the conductive layer in a range of 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ Ω · cm. 4. The tin dioxide doped with a foreign atom,
The lithographic printing plate manufacturing sheet according to claim 3, wherein the lithographic printing plate is tin dioxide doped with antimony. 5. The conductive layer has a volume resistivity of 1.0 × 10 ^6.
The lithographic printing plate manufacturing sheet according to claim 3, wherein the lithographic printing plate production sheet is in a range of from about 1.0 × 10 ⁸ Ω · cm. 6. The support according to claim 3, wherein at least a part of the side surface of the support is provided with a border containing a conductive material.
A lithographic printing plate manufacturing sheet according to any one of the above.