JPS59211051A - Manufacturing method of waterless lithographic printing original plate - Google Patents

Abstract

PURPOSE:To obtain high resolution and sharpness without any toner fixing step by forming the original toner image of a waterless lithographic plate through the direct electrophotographic method, photohardening a photopolymerizable silicone layer, and removing a light transmitting insulating sheet. CONSTITUTION:A transparent ink-repellent layer 4 composed essentially of an unhardened photopolymerizable silicone compd. is formed on a photoconductive master substrate 3, and further, a light transmitting insulating sheet 5 is formed on the layer 4. A toner image 6 is formed on the surface of the sheet 5 of the obtained plate material by using the electrophotographic process of the reversal electric field method. The layer 4 is uniformly exposed to UV rays through the toner image to harden the nonimage parts made of the hardened silicone layer, i.e., the ink repellent layer 7 and the image parts consisting of the disclosed face of the master substrate 3, i.e., the ink receiving face 8 is formed by removing the sheet 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a lithographic printing original plate that allows offset printing without using dampening water.

In the past, various methods have been developed and proposed as methods for producing waterless lithographic printing plates. One of them is an electrophotographic process based on the Noirson method, in which a desired color is formed on an ink-repellent layer such as silicone. There is a method of manufacturing a printing plate by forming an image.

Specifically, there is a direct method in which an I-ner image is created and fixed directly on a surface layer made by dispersing a photoconductor in a binder resin using an electrophasic method, and a printing plate is created, and a xerography method is used. There is an indirect method in which a toner image once formed on the photoreceptor-F is transferred and fixed onto an ink repellent layer of a plate material prepared in advance. The manufacturing method of waterless lithographic printing original plates that applies electrophotographic technology has great expectations mainly in the light printing field because the plate-making operation is simpler than the photolithography method that uses lithographic film. There are some problems.

That is, in both the electrophasis method and the serography method, it is difficult to fix the ink-philic toner on the surface of the ink-repellent layer, which has a low surface energy, and printing durability becomes a problem. In order to solve this problem, for example, a substance that promotes toner adhesion is added to the ink repellent layer (Japanese Patent Application Laid-Open No. 49-2012
1204, etc.), using a reactive ink repellent substance (Japanese Patent Laid-Open No. 52-56607), and after adhering toner on the surface of the uncured or semi-cured ink repellent layer, the ink repellent layer is further cured (Japanese Patent Laid-Open No. 52-56607). (1984-5105, etc.), pressing and embedding toner in an ink-repellent layer (1802-1982, etc.), fixing toner on an ink-repellent layer having a finely uneven surface (Japanese Patent Publication No. 54-78202) , to improve toner adhesion by modifying ink-repellent substances (Japanese Unexamined Patent Application Publication No. 1983-1999)
-7470.2, etc.) have been proposed, but no solution has been found yet.

On the other hand, the latter indirect method involves a step of transferring a toner image, and therefore has the disadvantage that the resolution and sharpness required for printed matter cannot be obtained.

In view of the above circumstances, the present invention provides that waterless lithographic printing plates are obtained by direct electrophotography, and that high resolution and sharpness can be easily obtained through a dry plate-making process without toner fixation. , and to obtain a printing plate with low printing durability.

That is, a transparent ink repellent layer mainly composed of an uncured photocurable silicone compound is provided on a photoconductive master substrate, and a reverse electric field is applied on the surface of the plate material, which is further provided with a light-transmitting and insulating sheet. A toner image is formed using an electrophotographic process, and then the entire surface of the toner image is exposed to ultraviolet rays to cure the photocurable silicone layer in the non-image area. This invention provides a method for producing a waterless lithographic printing original plate, characterized in that by removing a sheet, a non-image area consisting of a cured silicone layer and an image area consisting of an exposed surface of the photoconductive master substrate are formed. be.

Hereinafter, the present invention will be explained in detail based on the drawings.

First, FIG. 1 is a cross-sectional view of a lithographic printing original plate obtained by the manufacturing method of the present invention, which is a photoconductive master in which a photoconductive layer 2 is provided on a conductive support 1. It is composed of a transparent ink repellent layer 4 which is mainly composed of an uncured photocurable silicone compound provided on the surface thereof, and a light-transmitting and insulating sheet 5.

Next, the plate-making process of the waterless lithographic printing original plate of the present invention is carried out in a second step.
This will be explained based on the diagram. A toner image 6 is formed on the surface of a plate material consisting of a photoconductive master substrate 3, a photopolymerizable silicone layer 4, and a light-transmitting and insulating sheet 5 using an electrophotographic process based on a reverse electric field method [Second Figure (B) 1゜The reverse electric field method mentioned here is specifically
27 and K disclosed in Japanese Patent Publication No. 42-23910
It refers to the IP method or NP method or the electrophotographic process disclosed in US Pat. No. 3,041,167, and is different from the normal Carlson method in the process of forming an external charge latent image. For example, after primary charging is performed, an electrostatic latent image can be created by performing secondary charging with the opposite polarity to the primary charging at the same time as exposure, and then uniformly exposing the entire surface.

Next, as shown in FIG. 2(C), the entire surface of the toner image 6 is exposed to light. In this case, the light source is an ultra-high-pressure mercury lamp, a metal halide lamp, or the like. By this exposure, the uncured silicone layer in the non-image area is photopolymerized and cured, and is fixed to the photoconductive master substrate 3 to form a cured ink repellent layer 7. On the other hand, the toner image 6 performs a masking function upon exposure, so that the silicone layer 4 under the image area is not photopolymerized and is peeled off from the photoconductive master substrate surface upon removal of the sheet 5. The ink receiving surface 8 of the substrate surface is exposed [FIG. 2(D)].

By the above method, it is possible to obtain a waterless lithographic printing original plate of the present invention in which the cured silicone layer surface is an ink-repelling surface and the substrate surface is an ink-receiving surface. As shown in FIG. 2(E), during printing, the ink 7 is deposited only on the ink receiving surface and no ink is deposited on the cured ink repellent layer 5, making it possible to print without dampening water.

In the manufacturing process i of this original plate, a coating layer 4 of photocurable silicone is provided on the photoconductive master substrate 3, and a light-transmitting sheet 5 is pressure-bonded to the coated surface, or a light-transmitting sheet 5 is placed on the surface of the transparent sheet 5. After applying a photocurable silicone coating layer 4 to the photoconductive master substrate 3, the photoconductive master substrate 3 is bonded to the photoconductive master substrate 3. As this crimping method, there is a method of pasting the two together and pressing with a roll, and a more advantageous method is a pasting roll,
There is the use of calendar rolls.

Representative examples of plate materials suitable for the present invention are shown below.

The photoconductive master substrate 3 is, for example, an aluminum plate,
Metal plates such as steel plates and stainless steel plates, conductive treated paper,
A conductive support 1 such as a plastic film or sheet or a composite sheet thereof is coated with ZnO, 5eXcas, Se.
Inorganic systems such as Te, azoles, anthracenes,
triphenylamines, polynuclear aromatic vinyl polymers,
It has an organic type such as phthalocyanine.

In the present invention, the ink repellent layer containing photocurable silicone as a main component is cured, and the photoconductive master substrate 3
In order to strengthen this adhesion, it is preferable that the surface of the master substrate be treated with a primer.

Primer 7 in this case includes vinyltris(2-methoxyethoxy)silane, 3-crisitoxypropyltrimethysilane,
3-Methacryloxybutrimethoxysilane, N
-(trimethoxysilylpropyl)ethylenecyamine,
Examples include 3-aminopropyltriethoxysilane and a partially hydrolyzed condensate of one or more mixtures thereof. When using these primers, if necessary, various resins such as polyester, cellulose derivatives, acrylic resins, etc. may be used in combination as binders.

Furthermore, currently known photosensitive resins can also be used, specifically photosensitive resins containing azide or diazo compounds or containing them in the polymer, those containing cinnamoyl groups or cinnamylidene compounds or containing them in the polymer, and those containing acryloyl compounds. Examples include those mixed or contained in a polymer.

Furthermore, as the light-transmitting sheet 5, saturated polyester,
Synthetic resin sheets such as triacetate, diacetate, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic resin, and polycarbonate are suitable.

The photocurable silicone used in the waterless lithographic plate of the present invention may be any silicone that can be easily cured by ultraviolet irradiation, such as an organopolymer having a siloxane unit bonded to a maleimide group or a maleimide group having a substituted atom or group. Siloxane (JP-A-5113907, etc.), organopolysiloxane having a siloxane group bonded with an acryloxy group or an acryloxy group having a substituted atom or a substituent (JP-A-52-113805, etc.), organopolysiloxane having a mercapto group-containing siloxane unit Mixtures of organopolysiloxanes having siloxane units containing siloxane groups (JP-A-53-17045); Mixtures of organopolysiloxanes having siloxane units containing vinyl groups and organohydrodiene polysiloxanes (JP-A-53-17045);
5907), a polysiloxane having a cinnamic acid group or an azide group in its side chain, or a mixture of a linear polysiloxane and a bisazide compound (CMC's ``Basics and Applications Photopolymer''), etc. can be used. be.

The above photocurable silicone may contain a photosensitizer,
A thermal polymerization inhibitor, a filler, etc. can be added. Further, a charge transfer substance may be added to the silicone layer in order to improve photosensitivity when forming a toner image on the surface of the original plate of the present invention by electrophotography.

By implementing the present invention, the following effects are expected.

■Direct electrophotographic process allows clear, high-resolution images to be produced on the ink-receiving surface.

(2) Since the ink repellent layer does not contain a photoconductive substance, sufficient ink repellency is obtained, and therefore no background stain occurs during printing. ■Unlike conventional methods, there is no need to worry about adhesion between the toner image and the silicone surface, and excellent printing durability can be stably obtained. ■It is possible to remove toner fog on silicone surfaces, which was difficult with conventional technology. ■Can perform correction processing such as adding and deleting images, which are essential to printing boards.

■A wide selection of toners is available, and liquid development is also possible.

■Wide range of ink selection. ■Dry plate making method.

Next, the present invention will be explained in more detail with reference to examples.

Example: ZnO49,
A dispersion of Zn○ obtained by mixing 5 parts by weight, 10 parts by weight of acrylic resin binder, 0.5 parts by weight of rose bengal, and 100 parts by weight of toluene was dried to a thickness of 15 um.
A photoconductive master substrate was prepared by coating and drying to obtain a photoconductive master substrate. An acrylic photosensitive liquid (manufactured by Topron Nito Ohka) was applied to this photoconductive master substrate to a dry coating thickness of 0 to 5 μm.
After transfer coating, the substrate was dried with hot air to give a primer treatment.

100 parts by weight of a cocondensation polymer of acrylic oxyprobyl trichlorosilane and α, ω-dihydroxydimethylorganopolysiloxane, 4-dimethylamino-4' on one side of a 9 pm thick light-transparent sheet, a polypropylene film.
- Trimethylsilylhency 11 - A photocurable silicone solution consisting of 5 parts by weight of phenone and 1000 parts by weight of toluene was applied and dried to a dry coating thickness of 5 Irm, and then laminated under pressure with the photoconductive master substrate, An original plate for waterless planographic printing was obtained.

This plate material was applied to an electrophotographic apparatus using a reverse electric field method, and a toner image was formed on the surface of the polypropylene film. Next, use a metal halide lamp on top of the plate material, using an 80W/n? When the photoconductive master substrate and the polypropylene film were peeled off after being irradiated with light for about 1 minute, cured silicone remained on the substrate and uncured silicone remained on the film. The photoconductive master substrates obtained in this way were labeled A, B, and Dick MODEL.
When used on a 320 offset printing press and printed without dampening water, about 10,000 clear prints were obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a plate material used in the present invention, and FIG. 2 is a process diagram showing a method for manufacturing a waterless lithographic printing original plate of the present invention. ■... Conductive support 2... Photoconductive layer 3... Photoconductive master substrate 4... Main component is uncured photocurable silicone. Ink repellent layer 5...Light transparent and insulating sheet 6...
・Toner image 7... Cured ink repellent layer... Ink receiving surface 9... Ink patent applicant Tomogawa Paper Mills Co., Ltd.

Claims (1)

[Claims] A transparent ink repellent layer mainly composed of an uncured photocurable silicone compound is provided on a photoconductive master substrate, and a light transmitting and insulating sheet is further provided on the surface of the plate material.
A toner image is formed using an electrophotographic process using a reverse electric field method, and then the entire surface of the toner image is exposed to ultraviolet light to cure the photocurable silicone layer in the non-image area. A method for producing a waterless lithographic printing original plate, characterized in that a non-image area consisting of a cured silicone layer and an image area consisting of an exposed surface of the photoconductive master substrate are formed by removing an insulating sheet.