EP1171303A1

EP1171303A1 - Direct drawing planographic printing plate and preparation method therefor

Info

Publication number: EP1171303A1
Application number: EP00911413A
Authority: EP
Inventors: Shinji Shimizu; Yasuhiko Kojima; Koji Oe
Original assignee: Kodak Graphics Holding Inc
Current assignee: Kodak Graphics Holding Inc
Priority date: 1999-03-29
Filing date: 2000-03-28
Publication date: 2002-01-16
Also published as: JP2000272265A; WO2000058095A1

Abstract

The present invention relates to a planographic original plate having a new image receptive layer and a new preparation method for a printing plate using the same. In the direct drawing type planographic original plate, at least one image receptive layer containing a photocatalytic metallic oxide is provided on a substrate, or a silicone layer on the substrate and an image receptive layer containing a photocatalytic titanium oxide are provided. The preparation method for a printing plate according to the present invention is a method comprising the steps of forming an oleophilic image on said original plate, and applying sunlight or ultraviolet ray to ultra-hydrophilize a non-image area to thereby obtain a printing plate. According to the present invention, after forming an image on an image receptive layer, the non-image area is ultra-hydrophilized by only sunlight or ultraviolet exposure, whereby an excellent printing plate can be easily obtained. Further, a direct drawing planographic original plate which has been ultra-hydrophilized can be used as a printing plate as it is by only drawing an image.

Description

DESCRIPTION

DIRECT DRAWING PLANOGRAPHIC PRINTING PLATE AND PREPARATION METHOD THEREFOR

Technical Field

The present invention relates to a direct drawing type planographic original plate used in the short-run printing field, and more specifically relates to a planographic original plate having an new image receptive layer and a new preparation method for a printing plate using the same. The present application is based on a Japanese Patent Application (Japanese Patent Application No. 11-85945), and the contents of which are incorporated herein by reference.

Background Art

A direct drawing type planographic plate used in the short-run printing field is a planographic type printing plate applying the principle that oily ink and water do not mix because of mutual repulsion, and having no concave or convex portions on the plate surface such as in a relief printing plate or a gravure. However, there are a hydrophilic non-image area and a oleophilic image area on the printing plate surface. When an ink roller is rotated after applying water to the non-image area on the printing plate, to apply ink thereto, the non-image area does not receive ink because of the repulsion between the water and the ink, on the other hand, the image area receives the ink while repelling the water. Thus, printing is performed by transferring the ink on the image area to a medium such as paper or the like.

The conventional direct drawing type planographic printing plate used for such purposes as mentioned above has a structure in which an image receptive layer composed of an inorganic pigment, water-soluble resin, water resistant agent and the like is provided on a substrate of a water-proof paper, a plastic film, or the like. An ink receptive area is formed on an image receptive layer by forming a oleophilic image by hand, typewriter or an ink-jet process using a oleophilic ink, or by transferring a toner image formed on an electrophotosensitive material to the image receptive layer and thermally fixing the toner image, or by heat fusion transfer of an image from an ink ribbon to the image receptive layer with a thermal transfer printer. A non-image area is desensitized by an etching treatment of the direct drawing type planographic printing plate on which the oleophilic image area is formed, and the non-image area becomes a hydrophilic area on printing. The thus produced direct drawing type planographic printing plates can be easily obtained by a simple operation as compared to a PS printing plate used in newspapers and commercial printing and the equipment to be used is compact and can be handled as office equipment. Therefore the direct drawing type planographic printing plate has been used exclusively in the short-run printing. Direct drawing type planographic printing plates can be simply and efficiently prepared compared to PS printing plates. However, the direct drawing type planographic printing plate as an office equipment has disadvantages such as the use of a corrosive etchant, the generation of bluing in prints that accompanies an etching treatment and the like. Therefore, the development of a process having no such problems has been desired.

Further, as a material for imparting a hydrophilicity to an image receptive layer in conventional direct drawing type planographic printing plates, exclusively zinc oxide is used. A hydrophilizing treatment for a non-image area is performed by hydrophilizing zinc oxide in a non-image area by an etching treatment, after an image formation. In this case, the addition of titanium oxide fine particles for preventing of greasing of non-image area and improving of durability is well known, for example, in Japanese Patent Application, Publication No. 56-80492, No. 56-80493, No. 57-173197, No. 58-181692, No. 61-3797, No. 62-157059, No. 62-261489, No. 63-166590, No. 63- 166591, No. 5-169892, No. 8-87138, and the like. However, the effect of the added titanium oxide fine particles is to allow the hydrophilized non-image area to stably maintain its hydrophilicity by the addition of an inorganic hydrophilic compound which is not affected by the etchant, and it is not a photocatalytic effect which provides an ultra-hydrophilicity by reaction with light. No photocatalytic effect can be observed.

Further, the contact angle of conventional direct drawing type planographic original plates with respect to water is 10 degrees or more, usually about 20 degrees, and there is no conventional direct drawing type planographic original plate which exhibits an ultra-hydrophilicity such that the contact angle is 10 degrees or less, and further 5 degrees or less with respect to water. Conventional direct drawing type planographic original plates do not have contact angles of 10 degrees or less formed by an non-image area and water before a hydrophilizing treatment by etchant is carried out. Further, it has not been known that a oleophilic image may be formed on an ultra- hydrophilic surface such that the contact angle is 10 degrees or less with respect to water and that a printing plate with a oleophilic image formed on an ultra-hydrophilic surface may be used as a direct drawing type printing plate.

On the other hand, metallic oxide materials having a photocatalytic effect, and particularly a number of techniques relating to a photocatalytic titanium oxide used as the center have been disclosed in, for example, Japanese Patent Application, Publication No. 7-155598, No. 7-222928, No. 8-66635, No. 8-117606, No. 8-131834, No. 8-131842, No. 8-175887, No. 8-224481, No. 8-267646, No. 9-939, No. 9-56742, No. 9-57912, No. 9-76395, No. 9-78791, No. 9-188850, No. 9-225387, No. 9-225388, No. 9-226041, No. 9-226042, No. 9-227805, No. 9-227829, No. 9-227156, No. 9- 227160, No. 9-227831, No. 9-227832, No. 9-241038, No. 9-314750, No. 10-50159, No. 10-67543, No. 10-72242, No. 10-81840, No. 10-85608, No. 10-85609, No. 10-85610, No. 10-95635, No. 10-114544, No. 10-114545, No. 10-114546, No. 10-140046, No. 10-146251, No. 10-147770, and No. 10-147771, and WO96/29375, WO97/23572 and the like. Thus, various useful materials providing self cleaning properties, easy cleaning properties, anti-dulling properties, anti-togging properties and antibacterial properties and the like due to the photocatalytic effects have been disclosed. However, no application of such useful materials to printing plates utilizing an ultra- hydrophilization phenomenon based on a photocatalytic reaction has been found, and it was not been well known that an image receptive layer composed of a photocatalytic metallic oxide is useful as a printing material.

The present inventors have produced a direct drawing type planographic printing plate provided with an image receptive layer including a metallic oxide compound having photocatalytic effects. As a result, the present inventors have found that a surface to which an ultra-hydrophilicity is imparted by photocatalytic effects due to metallic oxide does not accept printing oily ink, and a hydrophilic area acting as a non-image area can be formed thereon. Further, the present inventors have also found that the hydrophilization can be performed by only irradiating the surface of the printing plate with light, without using an etchant or the like. As the result, the present inventors have made the present invention.

Accordingly, the first object of the present invention is to provide a new direct drawing type planographic original plate having an ultra-hydrophilic image receptive layer. Further, the second object of the present invention is to provide a new direct drawing type planographic original plate having at least one ultra-hydrophilic image receptive layer including a photocatalytic metallic oxide. Further, the third object of the present invention is to provide a method for producing a new direct drawing type planographic original plate having an ultra-hydrophilic image receptive layer by a ultra- hydrophilization in which sunlight or ultraviolet ray is applied to the new direct drawing type planographic original plate having at least one ultra-hydrophilic image receptive layer including a photocatalytic metallic oxide according to the present invention. Further, the fourth object of the present invention is to provide a simple hydrophilizing method by light in which after forming an oleophilic image area, a non-image area is hydrophilized by applying sunlight or ultraviolet ray to the direct drawing type planographic original plate according to the present invention without using an etchant. And the fifth object of the present invention is to provide a preparation method for an excellent planographic printing plate by forming an oleosus image area and imparting a hydrophilicity to a non-image area by applying sunlight or ultraviolet ray using a direct type planographic original plate.

Disclosure of Invention

The above-mentioned objects can be attained by a preparation method for a printing plate comprising the steps of producing a direct drawing type planographic original plate provided with at least one ultra-hydrophilic image receptive layer containing a photocatalytic metallic oxide on a substrate, forming an oleophilic image on the surface of the original plate, and imparting a hydrophilicity to an image receptive layer by applying sunlight or ultraviolet ray thereto after the step of forming the oleophilic image.

That is, the first configuration of the present invention relates to a direct drawing type planographic original plate, which is characterized in that at least one image receptive layer containing a photocatalytic metallic oxide is provided on a substrate. In such a direct drawing type planographic original plate, after forming an image on an image receptive layer, a non-image area will be ultra-hydrophilized by only applying sunlight or ultraviolet ray thereto, whereby an excellent printing plate can be easily prepared. Further, a direct drawing type planographic original plate according to the present invention is characterized in that it has a silicone layer on a substrate, and at least one image receptive layer containing a photocatalytic titanium oxide is provided on the silicone layer.

Further, the present invention relates to a direct drawing type planographic original plate in which a solid acid is added to said image receptive layer or metal doping is carried out to enhance the effects of an ultra-hydrophilization of the image receptive layer by light.

Further, the present invention relates to a new direct drawing type planographic original plate which is obtained by ultra-hydrophilizing the image receptive layer by applying sunlight or ultraviolet ray to a direct drawing type planographic original plate provided with at least one image receptive layer containing a photocatalytic metallic oxide on a substrate. Such a direct drawing type planographic original plate can be used as it is as a printing plate by merely drawing a oleophilic image on the image receptive layer.

The second configuration of the present invention is a preparation method for a printing plate characterized in that after forming a oleophilic image on the image receptive layer of said direct drawing type planographic original plate, sunlight or ultraviolet ray is applied thereto to ultra-hydrophilize the image receptive layer to thereby obtain a printing plate. According to such a preparation method for a printing plate, after forming an image on an image receptive layer the non-image area becomes ultra-hydrophilic by merely applying sunlight or ultraviolet ray thereto and an excellent printing plate can be easily obtained.

Further, the preparation method for a printing plate according to the present invention is a preparation method for a printing plate, in which a oleophilic image is formed on an image receptive layer of a direct drawing type planographic original plate ultra-hydrophilized by sunlight or ultraviolet exposure before forming the oleophilic image. According to such a preparation method for a printing plate, an excellent printing plate can be easily obtained by only drawing a oleophilic image on a direct drawing type planographic original plate previously ultra-hydrophilized.

Further, the present invention relates to a preparation method for a printing plate, in which a method for forming a oleophilic image in a preparation method for a printing plate is a method selected from the groups of method of forming a oleophilic image by hand, a typewriter or an ink-jet process using a oleophilic ink, or a method of forming a oleophilic image by transferring a toner image formed on an electrophotosensitive material to an image receptive layer and thermally fixing the toner image, or a method of forming a oleophilic image by the heat fusion transfer of an image from an ink ribbon using a thermal transfer printer.

Best Mode for Carrying out the Invention

The direct drawing type planographic original plate of the present invention is characterized in that at least one image receptive layer containing a photocatalytic metallic oxide is provided on a substrate. An image receptive layer including a photocatalytic metallic oxide will be described below.

As photocatalytic metallic oxides which may include in an image receptive layer of a direct drawing type planographic original plate according to the present invention, titanium oxide, zinc oxide, tin oxide, strontium titanate, tungsten trioxide, bismuth trioxide and iron (II) oxide can be used, and titanium oxide is preferably used.

As a photocatalytic titanium oxide any one of a rutile titanium oxide, an anatase titanium oxide, and an amorphous titanium oxide can be used. Thus, photocatalytic anatase titanium oxides which are commercially available from a number of producers can be utilized. For example, powdered photocatalytic anatase titanium oxides include the ST series of Ishihara Techno Corp., the SSP series of Sakai Chemical Industry Co., Ltd., the PC series of Titan Kogyo K.K., A-100 of Taki Chemical Co., Ltd., AMT/ATM of Tayca Corp., the TP series of Fuji Titanium Industry Co., Ltd., the DN series of Furukawa Co., Ltd., P25 of Nippon Aerosil Corporated, the F series of Showa Denko K.K., and the like. Alternatively, sol photocatalytic anatase titanium oxides include the STS series of Ishihara Techno Corp., the CBS series of Sakai Chemical Industry Co., Ltd., Titaniasol of Tayca Corp., the FS series of Furukawa Co., Ltd., H-40, N-40, CA-62 and the like of Taki Chemical Co., Ltd.

The first method of forming an image receptive layer using these powdered or sol photocatalytic titanium oxides includes a method comprising the steps of applying a suspension containing anatase or rutile titanium oxide particles or sol and silica particles or sol on a substrate and heating it to sinter at a temperature lower than the softening point of the substrate. The heating temperature is in a range of 200 °C to 1000 °C, and the heating time is in a range of 1 min to 1 hour. The substrates which can be used in this method include metal sheets such as a steel sheet, a stainless steel sheet, a galvanized sheet and the like, or a glass sheet. The ratio of titanium oxide used is in a range of 10 to 100 % by weight, preferably 40 to 80 % by weight.

Further, the second method of providing powdered or sol photocatalytic titanium oxides in an image receptive layer includes a method using a binder having film-forming properties, which holds finely divided titanium oxides. When a binder resin according to a usual organic compound is used, an oxidation reaction due to a photocatalytic effect occurs whereby the resin strength is reduced and the phenomena such as disintegration and the like occur. Therefore, the use of a binder resin according to a usual organic compound is not suitable. The second preferable methods include a method comprising the steps of applying an coating solution for an image receptive layer, which solution is prepared by dispersion of a powdered or sol photocatalytic titanium oxide in a film-forming element composed of non-cured or partially cured silicone (organopolysiloxane) or a precursor of silicone, to the substrate or the interlayer positioned on the substrate, and forming an image receptive layer by curing the film-forming element.

The film-forming elements for the image receptive layer include, in addition to a silicone precursor which is an essential component having film-forming properties, solvents such as water, methanol, ethanol, propanol, isopropanol, butanol and the like, catalysts for curing silicone precursors such as basic compounds such as tributylamine, hexilamine and the like, acid compounds such as hydrochloric acid, nitric acid, sulfuric acid, aluminum triisopropoxide, tetraisopropyl titanate and the like, and surface-active agents for enhancing the dispersion properties of a silane coupling agent and the like to a coating solution.

The silicone precursors may include various organic group substituted alkoxysilane compounds, alkoxysilane compounds, organic group substituted halogenosilane compounds, halogenosilane compounds, halogenoalkoxysilane compounds, and hydrosilane compounds.

Concrete examples of the silicone precursor may include, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n- propyltripropoxysilane, n-propyltributoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane, tetrachlorosilane, dimethoxymethylchlorosilane, diethoxydichlorosilane, triethoxychlorosilane, diphenyldichlorosilane, phenylmethyldibromsilane, trichlorohydrosilane, trimethoxyhydrosilane, vinyltrichlorosilane, vinyltrimethoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltrimethoxysilane, γ- glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ- aminopropyltriisopropoxysilane, γ-mercaptopropyltrimethoxysilane, γ- mercaptopropylmethyldimethoxysilane, and the like.

As the silicone precursor, dimers, trimers, oligomers and the like obtained as partially hydrolyzed products and dehydrated polycondensates can also be used. Alternatively, organopolysilazane compounds having a silazane bond can also be used in place of silicone having the siloxane bond.

To ensure excellent hardness and smoothness of the silicone film 10 mol% or more of three-dimensional cross-linked siloxane is preferably contained. Further, to ensure the flexibility of the film 60 mol% or less of two-dimensional cross-linked siloxane is preferably contained. The content of a photocatalytic titanium oxide in an image receptive layer is in a range of 10 to 100% by weight, preferably 40 to 70% by weight.

Further, a condition necessary for curing silicone in this case is a temperature of from room temperature to 300 °C. The desired image receptive layer can be formed by curing silicone at that temperature for 5 min to several hours. Accordingly, the method using a silicone film is suitable for substrates which are easily thermally denatured, such as water-proof paper, resin films, resin plates or the like.

Alternatively, methods for preparing another photocatalytic titanium oxide include a method of baking amorphous titanium oxide to change the phase of the amorphous titanium oxide to crystalline titanium oxide. This method comprises the steps of first applying amorphous titanium oxide onto a substrate, and baking it to sinter at 200 °C or more for 1 min to several hours. The formation of amorphous titanium oxide is carried out by the following methods.

Amorphous titanium oxide can be formed by dehydration polycondensation of titanium oxide comprising the steps of adding a hydrolysis inhibitor such as hydrochloric acid or ethylamine to a titanium alkoxide compound, for example, tetramethoxy titanium, tetraethoxy titanium, tetraisopropoxy titanium, tetra-n-propoxy titanium, and tetrabutoxy titanium, diluting the mixture with alcohol type organic solvent such as ethanol or propanol, partially or fully advancing hydrolysis, applying the mixture onto the substrate with a well-known application method such as a dipping method, a spin coating method, a nozzle flow coating method, a spraying method, a reverse coating method, flexo method, a printing method, a flow coating method, a bar coating method cr the like, and drying the obtained structure at a temperature of room temperature to 200 °C for 5 min to several hours. In this case an organic titanium compound such as a titanium chelate or acetate may be used in place of a titanium alkoxide compound.

Amorphous titanium can be formed by the dehydration polycondensation of titanium oxide comprising the steps of applying an acid water solution of an inorganic titanium compound, for example titanium tetrachloride or titanium sulfate, to a substrate by a well-known method such as a dipping method, spin coating method, a nozzle flow coating method, a spraying method, a flow coating method, a bar coating method or the like, and drying the obtained structure at a temperature in a range of room temperature to 200 °C for 5 min to several hours. Or amorphous titanium oxide may be formed on the surface of a substrate by chemical vapor deposition of titanium tetrachloride.

The obtained amorphous titanium oxide can be changed to an anatase type titanium oxide by baking it at a temperature in the range of 300 °C to 500 °C for several min to several hours, and can also be changed to a rutile type titanium oxide by baking it at a temperature of 600 °C or more for several min to several hours. In the present invention any titanium oxide can be preferably used.

The first method of forming an image receptive layer according to the present invention using the above-mentioned amorphous titanium oxide comprises the steps of baking an amorphous titanium oxide layer formed on the substrate and using it as-is as an image receptive layer.

The second method of forming an image receptive layer according to the present invention using the amorphous titanium oxide comprises the steps of forming a very thin amorphous silica layer on the formed amorphous titanium oxide layer and then baking the amorphous silica layer under the same conditions as the baking temperature of the amorphous titanium oxide. In this case, the method of forming an amorphous silica layer can be carried out in accordance with the method of forming the above- mentioned silicone film. That is, an amorphous silica layer can be formed by applying a coating solution prepared by mixing a silicone precursor which is essential component having the above-mentioned film-forming properties with water and/or an alcohol type organic solvent, a catalyst which cures the silicone precursor and a surface active agent which enhances the dispersion properties of the coating solution, to the surface of an amorphous titanium oxide in accordance with an well-known application method, and then curing the obtained structure at a temperature in a range of room temperature to 300 °C for 5 min to several hours. As described above, an image receptive layer in which an amorphous silica layer is provided on a photocatalytic titanium layer can be formed.

Alternatively, the third method of forming an image receptive layer according to the present invention using the amorphous titanium oxide is as follows. First, a silica particle-dispersed amorphous titanium oxide thin film in which the hydrolysis and dehydration polycondensation of titanium compound are carried out is formed by applying a suspension in which silica particles or sol are dispersed in a solution of an organic titanium compound such as titanium alkoxide, chelate or acetate, or in a solution of an inorganic titanium compound such as titanium tetrachloride or titanium sulfate, to the surface of the substrate, and heating the obtained structure at a temperature in a range of room temperature to 200 °C. Then, the amorphous titanium oxide thin film is heated at a temperature of 300 °C or more and a temperature of the softening point of the substrate or less, whereby the image receptive layer of the present invention in which the amorphous titanium oxide has been phase-changed to a crystalline titanium oxide and at the same time silica particles are dispersed is formed.

Alternatively, the fourth method of forming an image receptive layer according to the present invention using the amorphous titanium oxide is as follows. First, a solution including a silicone precursor having film-forming properties, water and/or alcohol type organic solvent, a catalyst which cures the silicone precursor, and a surface active agent which enhances the dispersion properties of the coating solution is mixed with a solution of an organic titanium compound such as titanium alkoxide, chelate or acetate, or a solution of an inorganic titanium compound such as titanium tetrachloride or titanium sulfate, the obtained solution is applied to the surface of the substrate in accordance with a well-known application method, and then the obtained structure is cured at a temperature of from room temperature to 300 °C for 5 min to several hours. As the result, an amorphous titanium oxide and amorphous silica mixed thin film can be formed. Then, the thin film is heated at a temperature of 300 °C or more and at a temperature of the softening point of the substrate or less, whereby an image receptive layer of the present invention in which the amorphous titanium oxide has been phase- changed to a crystalline titanium oxide and at the same time the photocatalytic titanium oxide is held by the amorphous silica is formed.

In any method of forming the image receptive layer, the amorphous titanium oxide is phase-changed to the crystalline titanium oxide. Thus, a heating temperature of 300 °C or more is necessary. Accordingly, as the substrate a metal sheet or a glass sheet or the like can be preferably used.

A plurality of photocatalytic metallic oxides can be contained in the image receptive layer of a direct drawing type planographic original plate according to the present invention. That is, at least one of photocatalytic metallic oxides of zinc oxide, tin oxide, strontium titanate, tungsten trioxide, bismuth trioxide, iron (II) oxide and the like, other than titanium oxide used as a photocatalytic metallic oxide, can be added. The additional method include, in the formation of a film of the above-mentioned image receptive layer, a method of adding metallic oxide powder or sol, an organic metal compound such as the alkoxide compound, chelate compound, acetate compound or the like, or an inorganic metal compound such as a halogenated compound, a sulfated compound, a nitrated compound or the like, to the coating solution. After that, the coating solution is applied to the substrate and the substrate is dried, so that a film is formed on the substrate. Then, the obtained structure is heated at a temperature of 400 °C or more to be baked , whereby an image receptive layer can be formed. The preferable combinations of these photocatalytic metallic oxides include the combination of a titanium oxide and a tungsten trioxide or of a titanium oxide and a tin oxide. The composition ratio of the respective photocatalytic metallic oxides is optional.

Solid acid can be added into the image receptive layer of a direct drawing type planographic original plate according to the present invention for the purpose of maintaining the ultra-hydrophilicity for a long time. The solid acids include, for example, a metallic oxide holding sulfuric acid, a metallic oxide holding nitric acid, a metallic oxide composite such as titanium oxide/aluminum oxide, titanium oxide/yttrium oxide, titanium oxide/tungsten oxide, titanium oxide/zirconium oxide, titanium oxide/molybdenum oxide, tungsten oxide/zirconium oxide, tungsten oxide/tin oxide and the like, and aluminum oxide/silica and the like. The addition method of these metallic oxides into the image receptive layer includes, in the formation of a film on the above-mentioned image receptive layer, a method of adding metallic oxide powder or sol, a organic metal compound such as an alkoxide compound, a chelate compound, an acetate compound or the like, or a inorganic metal compound such as a halogenated compound, a sulfated compound, a nitrated compound or the like, which are used as the precursor of the metallic oxides, to the coating solution. After that, the coating solution is applied to the substrate and the substrate is dried, so that a film is formed on the substrate. Then, the obtained structure is heated at a temperature of 400 °C or more to be baked, whereby an image receptive layer can be formed. The precursors of the above-described metallic oxides are as follows. The precursors of aluminum oxides include, for example, aluminum acetylacetonate, aluminum ammonium sulfate, aluminum bromide, aluminum n-butoxide, aluminum sec-butoxide, aluminum tert-butoxide, aluminum chloride, aluminum ethoxide, aluminum fluoride, aluminum iodide, aluminum methoxide, aluminum isopropoxide and the like. The precursors of the yttrium oxide include, for example, yttrium acetate, yttrium acetylacetonate, yttrium carbonate, yttrium chloride, yttrium fluoride, yttrium nitrate, and the like. The precursors of the tungsten oxide include, for example, tungsten chloride, tungsten hexacalbonyl, tungstic acid, phosphotungstic acid, silicotungstic acid and the like. The precursors of the zirconium oxide include, for example, zirconium acetylacetonate, zirconium n-butoxide, zirconium chloride, zirconium isopropoxide, zirconium oxynitrate, zirconium oxychloride, zirconium sulfate, and the like. The precursors of the molybdenum oxide include, for example, molybdenum chloride, molybdenum hexacalbonyl, molybdenylacetylacetonate, molybdic acid, molybdophosphoric acid, and the like. The precursors of the tin oxide include, for example, tin acetate, tin bromide, tin chloride, tin fluoride, tin iodide, tin oxalate, tin sulfate, and the like. Further the precursors of silica include the above-mentioned silicone precursors and the like. The precursors preferably used are titanium oxide/tungsten oxide baked at 600 °C to 800 °C, tungsten oxide/zirconium oxide baked at 700 °C to 900 °C, tungsten oxide/tin oxide baked at 900 °C to 1100 °C, and the like. The precursor further preferably used is aluminum oxide/silica baked at 400 °C to 600 °C.

The above-described metallic oxide composites are used by adding them to an image receptive layer. Further, by also providing another layer of the metallic oxide composite on the image receptive layer, an ultra-hydrophilic surface can be formed.

Doping of platinum group metal in the image receptive layer of a direct drawing type planographic original plate according to the present invention can be carried out to increase the ultra-hydrophilicity provided by the photocatalytic metallic oxide. The platinum group metals which can be used are metals such as platinum, vanadium, rhodium, ruthenium, osmium, iridium, and the like. The doping method into the image receptive layer include a method of adding these soluble platinum group metallic salts together with other elements in the stage of forming a film of the image receptive layer, and a method of applying these soluble platinum group metallic salts after forming the film of the image receptive layer, thereby to perform photoreducing precipitation, and the like. The amount of platinum group metal for doping is 10^~9 mol to 10^"3 mol, preferably 10^"^ mol to 10^~5 mol with respect to 1 mol of photocatalytic metallic oxide.

The above-described image receptive layer is provided on the substrate directly or on a primary coat or an interlayer by application so that a direct drawing type planographic original plate according to the present invention is produced.

As the substrates which can be used in the present invention, a water-proof paper, a plastic film of polyester, polyethylene terephthalate, polyethylene naphthalate or the like, a resin plate of vinyl chloride, polycarbonate, fluorine plastic or the like, a metallic plate with a thickness of 0.5 mm or less of steel sheet, stainless steel sheet, galvanized sheet, tinplate, nickel-plated sheet or the like, a glass plate with a thickness of 0.5 mm or less, and the like can be used.

When heat treatment at a temperature of 200 °C or more is required in forming the above-described image receptive layer, a metallic sheet such as a stainless steel sheet or a galvanized sheet or the like is preferably use as a substrate. In a case of the heat treatment at 200 °C or less an aluminum substrate or a plastic film is preferably used as the substrate.

If in a direct drawing type planographic original plate according to the present invention the substrate is composed of a metallic plate or a glass plate having a comparatively hydrophilicity, the above-described image receptive layer can be directly applied thereon to produce a printing plate. However, if the substrate is composed of a plastic film or a plastic plate or the like, a silicone layer as an adhesive linkage or an interlayer is preferably provided between the substrate and the lowest layer of at least one image receptive layer.

Methods of forming a silicone layer on the surface of a substrate include a method of applying a coating solution for a silicone layer on the surface of the substrate and curing the applied portion. The coating solution for the silicone layer contains a silicone precursor as the essential component of the solution. Additionally, to the coating solution for the silicone layer can be added solvents such as water, methanol, ethanol, propanol, isopropanol, butanol and the like, catalysts for curing silicone precursors such as basic compounds such as tributylamine, hexilamine and the like, acid compounds such as hydrochloric acid, nitric acid, sulfuric acid, aluminum triisopropoxide, tetraisopropyl titanate and the like, and surface-active agents for enhancing the dispersion properties of a silane coupling agent to a coating solution and the like.

The silicone precursors include silane compounds having two univalent organic groups and two alkoxy groups or two halogen atoms, silane compounds having two univalent organic groups and one alkoxy group or one halogen atom, silane compounds having two hydrogen atoms and two alkoxy groups or two halogen atoms, silane compounds having two hydrogen atoms and one alkoxy group or one halogen atoms, silane compounds having one univalent organic group, one hydrogen atom and two alkoxy groups or two halogen atoms, silane compounds having one univalent organic group, one hydrogen atom, one alkoxy group and one halogen atom, silane compounds having one univalent organic group and three alkoxy groups or three halogen atoms, silane compounds having one univalent organic group, two alkoxy groups and one halogen atom, silane compounds having one univalent organic group, one alkoxy group and two halogen atoms, silane compounds having one hydrogen atom and three alkoxy groups or three halogen atoms, silane compounds having one hydrogen atom, two alkoxy groups and one halogen atom, silane compounds having one hydrogen atom, one alkoxy group and two halogen atoms, silane compounds substituted by four alkoxy groups, a silane compounds having three alkoxy groups and one halogen atom, silane compounds having two alkoxy groups and two halogen atoms, silane compounds having one alkoxy group and three halogen atoms, or silane compounds substituted by four halogen atoms.

Concrete examples of these silicone precursors include, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n- propyltripropoxysilane, n-propyltributoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane, tetrachlorosilane, dimethoxymethylchlorosilane, diethoxydichlorosilane, triethoxychlorosilane, and the like. As the silicone precursor, dimers, trimers, and oligomers and the like obtained as partially hydrolyzed products and dehydrated polycondensates can also be used.

As the application method of the above-mentioned coating solution for the silicone layer well-known application methods such as a dipping method, a spin coating method, a nozzle flow coating method, a spraying method, a reverse coating method, flexo method, a printing method, a flow coating method, a bar coating method and the like can be used.

The silicone layer curing method include a method of polycondensing the silicone precursor by heating, leaving it at room temperature, ultraviolet exposure, or the like. The thickness of the silicone layer is preferably several nm to several μm.

A direct drawing type planographic original plate can be produced by applying a coating solution for an image receptive layer to the above-mentioned substrate or silicone layer, and subjecting it to drying for polycondensation and/or baking. The composition of the coating solution for the image receptive layer and the conditions of the drying for polycondensation or baking are as described above. As the application method of the coating solution for the image receptive layer, well-known application method such as a dipping method, a spin coating method, a nozzle flow coating method, a spraying method, a reverse coating method, flexo method, a printing method, a flow coating method, a bar coating method and the like can be used.

The thickness of the image receptive layer produced as mentioned above is preferably several nm to several μm because this allows the photocatalytic reaction to be sufficiently carried out.

When the direct drawing type planographic original plate produced by the above described processes is further irradiated with light, an ultra-hydrophilic direct drawing type planographic original plate having an ultra-hydrophilic surface according to the present invention can be produced.

As the conditions of hydrophilization of the original plate, while using a light source such as sunlight, fluorescent lighting, incandescent lamps, metal halide lamps, mercury vapor lamps, or the like, the light irradiation time is continued for several min to 10 days. As the result, an ultra-hydrophilic direct drawing type planographic original plate having a water contact angle of 10 degrees or less with respect to the surface of the original plate can be obtained.

Next, preparation method for a printing plate using a direct drawing type planographic original plate according to the present invention will be described.

The method of drawing an image using a oleophilic ink on an image receptive layer of the direct drawing type planographic original plate according to the present invention can be carried out by any well-know means. The image receptive layer of a direct drawing type planographic original plate according to the present invention usually has a water contact angle of about 20 degrees with respect to the surface of the layer, which is the same as in a conventional direct drawing type planographic original plate. Thus, drawing a image on the image receptive layer is not a problem. On the other hand, even in a direct drawing type planographic original plate according to the present invention having an ultra-hydrophilized image receptive layer so as to have a contact angle of 10 degrees or less, image drawing can also be performed using a oleophilic ink. Therefore, it was surprising that a stable printing could be performed with the printing ink using the thus obtained printing plate.

Well-known drawing means include a means of forming a oleophilic image by hand, a typewriter, or an ink-jet process using a oleophilic ink, or a means of transferring a toner image formed on an electrophotosensitive material to a image receptive layer and forming a oleophilic image by thermally fixing the toner image, or a means of forming a oleophilic image by heat fusion transferring an image from an ink ribbon to a image receptive layer with a thermal at transfer printer, or the like.

A preparation method for a printing plate according to the present invention is characterized in a hydrophilization by light. That is, in a direct drawing type planographic printing plate according to the present invention having an image applied thereto, the non-image area of the image receptive layer is hydrophilized by light exposure. As a light source which can be used, if the light source applies UV radiation with a wavelength of 400 nm or less, any light source can be used. Specifically, sunlight, fluorescent lighting, incandescent lamps, metal halide lamps, mercury vapor lamps, or the like can be used. Although the exposure times differ depending on the light intensity of the light source, several min. to several hours are required. Particularly, in the case of sunlight, several days to about 10 days are required. Although the contact angle of a direct drawing type planographic original plate with respect to water is first about 20 degrees, the direct drawing type planographic original plate according to the present invention can be used as a printing plate by changing the contact angle to 10 degrees or less, preferably 5 degrees or less, by light exposure. Incidentally, in the case of a direct drawing type planographic original plate in which the image receptive layer is previously ultra-hydrophilized by light exposure, printing can be carried out without special treatment after image drawing. Further, the thus produced area having an ultra-hydrophilicity is comparatively stable. Thus, the ultra- hydrophilicity can be maintained for several days as it is. Further, the ultra- hydrophilicity can also be recovered by exposure to ultraviolet ray as required.

An image receptive layer containing a photocatalytic metallic oxide, which was produced by the method according to the present invention, is strong and usually capable of enduring printing runs of twenty thousand sheets to fifty thousand sheets. Further, there are no problems such as a greasing due to printing ink contamination in the non-image area due to the feature of the layer's ultra-hydrophilicity.

The printing plate prepared by the above-described method is provided for printing of the next step.

Example

Next, the present invention will be described in detail by examples. However, the present invention is not limited to these examples. [Example 1]

A silica coating solution consisting of 10.0 g of MKC silicate MS 56 (manufactured by Mitsubishi Chemical Corp.) which is a partially hydrolyzed condensate of tetramethoxysilane, 40.0 g of methanol, and 1.0 g of 0.01 N hydrochloric acid were applied to a previously degreased B4 wide aluminum plate using a bar of rod number #16. After drying the aluminum plate with the solution applied at 80 °C for 10 min, a mixed coating solution consisting of 2.0 g of tetrabuthoxysilane BTS (manufactured by Mitsubishi Chemical Corp.), 3.0 g of anatase type titania sol TA-15 (manufactured by Nissan Chemical Industries, Ltd.), 60.0 g of ethanol, and 1.0 g of water was applied to the dried aluminum plate using a bar of rod number #12. After drying and heating the aluminum plate at 150 °C for 30 min an image receptive layer in which anatase type titania particles were bonded with a binder of amorphous silica was formed.

After the direct drawing type planographic original plate according to the present invention formed by the above-described process was mounted on a solid ink- jet image drawing machine IJP-1000 (manufactured by Polychrome Corp.), character and image information from a computer was drawn on the direct drawing type printing plate. Ultraviolet ray was applied to the entire surface of the obtained printing plate material from a distance of 1 m away for 1 hour with an R-51A type ultraviolet light hand lamp (manufactured by Irie Shokai Co., Ltd.) to complete the ultra-hydrophilizing treatment, thereby to obtain a printing plate (1). The contact angle of the non-image area with respect to water was 5 degrees or less.

The printing plate (1) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 2000 sheets were conducted under the following conditions. Printing speed: 4000 sheets/hour, Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 2000 sheets of character prints thus produced were excellent prints having no problems in quality or the like. [Example 2] A mixed coating solution consisting of 10.0 g of anatase type titania sol TA-15 (manufactured by Nissan Chemical Industries, Ltd.) and lO.Og of tin oxide sol (manufactured by Taki Chemicals. Co., Ltd.) was applied to a previously degreased B4 wide stainless steel plate at 500 rpm with a compact whirler (manufactured by Dainippon Screen MFG. Co., Ltd.). After that stainless steel plate with the applied solution was baked at 750 °C for 10 min to obtain a direct drawing type planographic original plate according to the present invention containing a solid acid.

After the direct drawing type planographic original plate formed by the above- described process was mounted on a solid ink-jet image drawing machine IJP-1000 (manufactured by Polychrome Corp.), character and image information from a computer was drawn on the direct drawing printing plate. Ultraviolet ray was applied to the entire surface of obtained printing plate material from a distance of 1 m away for 1 hour with an R-51A type ultraviolet light hand lamp (manufactured by Irie Shokai Co., Ltd.) to complete the ultra-hydrophilizing treatment, to thereby obtain a printing plate (2). The contact angle of the non-image area with respect to water was 5 degrees or less.

The printing plate (2) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 2000 sheets were conducted under the following conditions. Printing speed: 1000 sheets/hour: Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 2000 sheets of character prints thus produced were excellent prints having no problems in quality and the like. [Example 3]

A mixed coating solution consisting of 3.4 g of tetrabuthoxytitanium, 1.0 g of acetylacetone, 1.0 g of water, and 100.0 g of ethanol was applied to a previously degreased B4 size stainless steel plate at 500 m with a compact whirler (manufactured by Dainippon Screen MFG. Co., Ltd.). After that the stainless steel plate with the applied solution was baked at 500 °C for 10 min. Further, a 0.1 weight% water solution of platinum chloride hexahydrate was applied to the surface of the obtained stainless steel plate at 1500 rpm with a compact whirler (manufactured by Dainippon Screen MFG. Co., Ltd.). After that the thus obtained plate was dried leaving by allowing it to stand for 10 min under 20 W blue light black fluorescent lightning (manufactured by Sankyo Electric Co. Ltd.). Thus, a direct drawing type planographic original plate according to the present invention in which the titania crystals were doped with platinum was obtained.

After the direct drawing type planographic original plate formed by the above- described process was mounted on a solid ink-jet image drawing machine IJP-1000 (manufactured by Polychrome Coφ.), character and image information from a computer was drawn on the direct drawing type printing plate. Ultraviolet ray was applied to the entire surface of the obtained printing plate material from a distance of 1 m away for 30 min with an R-51A type ultraviolet light hand lamp (manufactured by Irie Shokai Co., Ltd.) to complete the ultra-hydrophilizing treatment, to thereby obtain a printing plate (3). The contact angle of the non-image area with respect to water was 5 degrees or less.

The printing plate (3) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 2000 sheets were conducted under the following conditions. Printing speed: 1000 sheets/hour, Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 2000 sheets of character prints thus produced were excellent prints having no problems in quality and the like. [Example 4] A silica coating solution consisting of 10.0 g of MKC silicate MS 56 (manufactured by Mitsubishi Chemical Corp.) which is a partially hydrolyzed condensate of tetramethoxysilane, 40.0 g of methanol, and 1.0 g of 0.01 N hydrochloric acid was applied to an A4 sized polyethylene terephthalate film using a bar of rod number #9. After drying the film with the applied solution at 80 °C for 10 min, a silicone layer was produced. Then a mixed coating solution consisting of 3.0 g of anatase type titania sol TA-15 (manufactured by Nissan Chemical Industries, Ltd.), 3.0 g of highly reactive silica dispersed solution MS51SGH (manufactured by Mitsubishi Chemical Coφ.), and 60.0 g of ethanol was applied to the silicone layer using a bar of rod number #9. After drying the obtained structure at 80 °C for 1 min, a direct drawing type planographic original plate according to the present invention in which a silicone containing a titania was formed as the image receptive layer was obtained.

After the direct drawing type planographic original plate produced by the above-described process was mounted on an MD-4000J (manufactured by Alps Electric Co. Ltd.), a thermo-sensitive transfer type printer, character and image information from a computer was drawn on the direct drawing printing plate. The obtained printing plate material was exposed to sunlight for 2 days to complete the ultra-hydrophilizing treatment. As the result a printing plate (4) was obtained. The contact angle of the non-image area with respect to water was 5 degrees or less.

The printing plate (4) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 1000 sheets were conducted under the following conditions. Printing speed: 5000 sheets/hour, Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 1000 sheets of character prints thus produced were excellent prints having no problems in quality and the like. [Example 5]

Ultraviolet ray was applied to the entire surface of the direct drawing type planographic original plate obtained in Example 4 from a distance of 1 m away for 1 hour with an R-51A type ultraviolet light hand lamp (manufactured by Irie Shokai Co., Ltd.) to complete the ultra-hydrophilizing treatment. As the result, a direct drawing type planographic original plate according to the present invention in which the image receptive layer was ultra-hydrophilized was obtained. The contact angle of the obtained image receptive layer with respect to water was 5 degrees or less. After the obtained ultra-hydrophilic direct drawing type planographic original plate was mounted on a MD-4000J (manufactured by Alps Electric Co. Ltd.), a thermo-sensitive transfer type printer, character and image information from a computer was drawn on the direct drawing printing plate. The obtained printing plate material was exposed to sunlight for 1 day to again complete the ultra-hydrophilizing treatment. As the result a printing plate (5) was obtained. The contact angle of the non-image area with respect to water was 5 degrees or less.

The printing plate (5) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 1000 sheets were conducted under the following conditions. Printing speed: 5000 sheets/hour, Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 1000 sheets of character prints thus obtained were excellent prints having no problems in quality and the like. [Example 6]

A silica coating solution consisting of 10.0 g of MKC silicate MS 56 (manufactured by Mitsubishi Chemical Corp.) which is a partially hydrolyzed condensate of tetramethoxysilane, 40.0 g of methanol, and 1.0 g of 0.01 N hydrochloric acid was applied to an A4 sized polyethylene terephthalate film using a bar of rod number #9. After drying the solution applied film at 80 °C for 10 min, a silicone layer was produced. Then a mixed coating solution consisting of 3.0 g of anatase type titania sol TA-15 (manufactured by Nissan Chemical Industries, Ltd.), 3.0 g of tetramethoxysilane partial hydrolytic condensate MS56S (manufactured by Mitsubishi Chemical Corp.), and 60.0 g of ethanol was applied to the silicone layer using a bar of rod number #9. After drying the obtained structure at 110 °C for 5 min, a direct drawing type planographic original plate according to the present invention in which a silicone containing a titania was formed as the image receptive layer was obtained.

Ultraviolet ray was applied to the entire surface of obtained printing plate material from a distance of 1 m away for 1 hour with an R-51A type ultraviolet light hand lamp (manufactured by Irie Shokai Co., Ltd.) to complete the ultra-hydrophilizing treatment. The contact angle of the non-image area with respect to water was 5 degrees or less. The direct drawing type planographic original plate according to the present invention in which the image receptive layer was ultra-hydrophilized was produced as described above.

A statistic transfer copier, a VIVACE455 (manufactured by Fuji Xerox Co., Ltd.) was used to transfer a toner image based on a manuscript to the ultra- hydrophilized direct drawing type planographic original plate, to obtain a printing plate (6).

The printing plate (6) was mounted on a printing machine (TOKO-820L; manufactured by Tokyo Airborne Instrument Co., Ltd.) to conduct printing tests. Printing tests for 5000 sheets were conducted under the following conditions. Printing speed: 5000 sheets/hour, Printing paper: Jujo Diacoat B4, Ink: GEOS-G magenta S (manufactured by Dainippon Ink & Chemicals, Inc.), Fountain solution: NA108W (1:50 dilution, manufactured by Dainippon Ink & Chemicals, Inc.). The 5000 sheets of character prints thus obtained were excellent prints having no problems in quality and the like.

Industrial Applicability

In a direct drawing type planographic original plate provided with at least one image receptive layer containing a photocatalytic metallic oxide on a substrate according to the present invention, a non-image area is ultra-hydrophilized by only the application of sunlight or ultraviolet ray after forming an image on the image receptive layer. Accordingly, the original plate according to the present invention can be used as an excellent printing plate. Further, a direct drawing type planographic original plate which has been ultra-hydrophilized can be used as a printing plate as it is, by only conducting image drawing.

Claims

1. A direct drawing type planographic original plate characterized in that at least one image receptive layer containing a photocatalytic metallic oxide is provided on a substrate.

2. The direct drawing type planographic original plate according to claim 1, wherein a silicone layer is provided on said substrate and said at least one image receptive layer is provided on said silicone layer.

3. The direct drawing type planographic original plate according to claim 1, wherein said image receptive layer is an image receptive layer which includes a solid acid.

4. The direct drawing type planographic original plate according to claim 1, wherein said image receptive layer is a metal doped image receptive layer.

5. The direct drawing type planographic original plate according to claim 1, wherein said image receptive layer is ultra-hydrophilized by sunlight or ultraviolet exposure.

6. A preparation method for a printing plate characterized in that after forming a oleophilic image on the image receptive layer of said direct drawing type planographic original plate according to claim 1, sunlight or ultraviolet ray is applied to ultra- hydrophilize the image receptive layer, whereby a printing plate is obtained.

7. The preparation method for a printing plate wherein a oleophilic image is formed on the image receptive layer of said direct drawing type planographic original plate according to claim 5, whereby a printing plate is obtained.

8. The preparation method for a printing plate according to claim 6, wherein said oleophilic image is formed by a method selected from a method of forming a oleophilic image by hand, typewriter or an ink-jet process using a oleophilic ink, or a method of forming a oleophilic image by transferring a toner image formed on an electrophotosensitive material to the image receptive layer and thermally fixing the toner image, or a method of forming a oleophilic image by heat fusion transferring an image from an ink ribbon to the image receptive layer with a thermal transfer printer.

9. The preparation method for a printing plate according to claim 7, wherein said oleophilic image is formed by a method selected from a method of forming a oleophilic image by hand, typewriter or an ink-jet process using a oleophilic ink, or a method of forming a oleophilic image by transferring a toner image formed on an electrophotosensitive material to the image receptive layer and thermally fixing the toner image, or a method of forming a oleophilic image by heat fusion transferring an image from an ink ribbon to the image receptive layer with a thermal transfer printer.