JPH0648057A - Plate material for direct drawing lithographic printing - Google Patents

Abstract

PURPOSE:To provide a direct drawing lithographic printing plate material wherein process can be performed with an electrostatic image transfer system copying machine, fog of an non-image part by scattering of toner is little, and process can be performed also with a thermal transfer system printer, and transfer of ink from an ink ribbon to the non-image part is little, and a printing stain is little. CONSTITUTION:A direct drawing type lithographic printing plate material is provided wherein an image acceptive layer containing zinc oxide, a binder, and 0.1-5% of an alcohol soluble antistatic agent is formed on a water proof base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drawing type planographic printing plate material. More specifically, the present invention is capable of plate making by an electrostatic transfer method such as a xerographic copying machine or a laser printer, or a thermal transfer method such as a thermal transfer printer, and there is little stain and printing durability. The present invention relates to a good lithographic printing plate material for direct drawing.

[0002]

2. Description of the Related Art With the recent development of office equipment and the development of office automation, in the light printing field, a direct drawing type capable of easily making a plate with an electrostatic transfer type copying machine, a laser printer, a thermal transfer printer, or the like. A printing method using a lithographic printing plate material is rapidly spreading.

A conventional direct drawing type lithographic printing plate material is an image receiving layer containing a pigment, a water-soluble binder and a water-proofing agent as main components on a support made of paper, plastic film or the like. . In such a direct drawing type lithographic printing plate, using a lipophilic ink, on the image receiving layer,
Form a lipophilic image by a typewriter or handwriting, or transfer the toner image formed on the electrophotographic photosensitive member to the image receiving layer of the lithographic printing plate, to form a lipophilic image by heat fixing it, Alternatively, a lipophilic image can be formed by thermal fusion transfer of an image from an ink ribbon with a thermal transfer printer.

In order to print using such a printing plate,
The non-image area is desensitized with an etching solution, and then used as a printing master for lithographic printing.

A direct drawing type lithographic printing plate material having an image receiving layer comprising an inorganic pigment, a water-soluble binder, a water-proofing agent and the like on a water-resistant support is, for example, Japanese Patent Publication No. 40-23581.
JP-A-48-9802, JP-A-57-20519
6, JP-A-60-2309, JP-A-57-1791.
JP-A-57-15998, JP-A-57-9690
No. 0, JP-A-57-205196, JP-A-63-16
6590, JP-A-63-166591, JP-A-63
No. 256493, JP-A No. 63-317388, and JP-A No. 1-114488.

The conventional direct drawing type lithographic printing plate material as described above is currently in decline. The first cause thereof is a drawback that toner is scattered during transfer of a toner image in a plate-making process of an electrostatic transfer system, causing fog in a non-image portion, which also becomes a background stain in printing.

Further, the conventional direct-drawing type lithographic printing plate material is more likely to cause printing stains and has a printing durability as compared with an electrophotographic offset master containing photoconductive zinc oxide and an oil-soluble binder as main components. It had the drawback of being low. That is, in the conventional direct-drawing type lithographic printing plate material, a hardener such as a melamine formaldehyde resin is used to improve its water resistance, and thereby a material having satisfactory water resistance can be obtained. Insufficient properties were caused, and as a result, print stains were likely to occur.

On the other hand, since a printing plate obtained by using only a binder having a strong hydrophilic property such as carboxymethyl cellulose has poor printing durability, a polyvalent metal salt is used as a binder curing agent. However, since the electric resistance of the image receiving layer is lowered, there is a drawback that the transfer efficiency of toner is deteriorated in the electrostatic transfer type plate making.

When used in a plate making method for making a lipophilic image by thermal melting transfer from an ink ribbon with a thermal transfer printer, when a conventional direct drawing type lithographic printing plate material is used, it is caused by friction between a paper feed roll and the plate. Since the plate is charged with static electricity and the ink ribbon and the plate are brought into close contact with each other, the ink of the ink ribbon is transferred to the non-image area, which causes printing stains during printing.

[0010]

DISCLOSURE OF THE INVENTION The present invention has little printing stains and excellent printing durability. In the electrostatic transfer type plate making, there is little fog stain in the non-image area due to scattering of toner, and the thermal transfer type. In the plate-making, the present invention provides a direct drawing type planographic printing plate material having less ink transfer to the non-image area.

[0011]

The inventors of the present invention have earnestly studied a direct drawing type lithographic printing plate material suitable for plate making by electrostatic transfer method and thermal transfer method, and as a result, as a pigment contained in an image receiving layer, oxidation was carried out. It was found that a direct drawing type lithographic printing plate material that solved the above-mentioned problems can be obtained by using zinc and adding a certain amount of an alcohol solvent-soluble antistatic agent to the image receiving layer, and completed the present invention. It was made.

That is, the direct-drawing type lithographic printing plate material of the present invention has a water resistant support and an image receiving layer formed on the water resistant support, and the image receiving layer is zinc oxide. , A binder resin, and 0.1 to 5% of an alcohol-soluble antistatic agent.

[0013]

In the direct drawing type lithographic printing plate material of the present invention, the pigment contained in the image receiving layer is zinc oxide, and the content of zinc oxide with respect to the total weight of the image receiving layer is 70% or more. It is more preferably 75% to 90%. When the content of zinc oxide is less than 70%, scumming may easily occur during printing.

The alcohol solvent-soluble antistatic agents used in the image-receiving layer of the present invention include cationic antistatic agents such as quaternary ammonium salts, nonionic antistatic agents, and anionic antistatic agents. You can choose
Preferably, a cationic antistatic agent is used. Since this antistatic agent is soluble in alcohol, it is possible to use water or an organic solvent such as toluene as a solvent for the coating solution for forming the image receiving layer.

The content of the alcohol-soluble antistatic agent in the image receiving layer is 0.1 based on the total weight of the image receiving layer.
-5%, preferably 0.5-3%. If this content is less than 0.1%, in the electrostatic transfer system,
Fogging in non-image areas due to toner scattering increases, and in the thermal transfer method, stains increase due to transfer of ink from the ink film. The content of the antistatic agent is 5%
If it exceeds the range, the transfer efficiency of the toner at the time of forming the image portion is lowered, and the print background is likely to be stained at the time of printing.

The dry weight of the image receiving layer of the plate material for direct drawing lithographic printing according to the present invention is preferably 4 to ²⁰ g / m ² . If this is less than 4 g / m ² , the desensitizing ability of the obtained printing plate material becomes insufficient, and printing stains are likely to occur. On the other hand, if it exceeds 20 g / m ² , the dielectric property is increased, so that fog due to toner scattering is increased in plate making by the electrostatic transfer system.

The binder resin used in the image receiving layer in the lithographic printing plate material of the present invention includes starch, starch derivatives,
Cellulose derivatives such as carboxymethyl cellulose and hydroxymethyl cellulose, water-soluble resins such as polyvinyl alcohol, modified polyvinyl alcohol, casein, and ammonium acrylate, and water such as acrylic resin, SBR, NBR, and vinyl acetate-ethylene copolymer. An insoluble and water-dispersible emulsion type resin can be used, and these resins can be used alone or in combination of two or more kinds. When only the water-soluble resin is used as the binder resin, in order to improve printing durability of the obtained printing plate material,
It is preferable to use an appropriate amount of a water-proofing agent in combination therewith.

Further, other binders used in the image receiving layer may include solvent-soluble (water-insoluble) resins such as polyester resin, acrylic resin, epoxy resin, polycarbonate resin, and butyral resin. In this case, the coating solution for the image receiving layer can be prepared using a solvent such as toluene.

The content of the binder in the image receiving layer is preferably 30% or less, more preferably 10 to 25%, based on the total weight of the image receiving layer. When the binder content exceeds 30%, desensitization of the non-image area of the obtained printing plate is insufficient, and scumming is likely to occur during printing.

Examples of the water-resistant support used in the present invention include paper or plastic film that has been subjected to water-proof treatment. In the case of a water resistant support using paper as a base material, a water resistant layer may be provided on the surface on which the image receiving layer is provided in order to improve printing durability. Further, a back coat layer may be provided on the back surface of the support to prevent curling.

By providing a solvent resistant layer between the water resistant layer and the image receiving layer, it becomes possible to provide the image receiving layer using a solvent soluble resin such as an acrylic resin.

The water resistant layer and the back coat layer are formed by using an emulsion type resin such as acrylic resin, SBR or NBR. These resins may be used alone or in combination of two or more kinds. Also,
An appropriate amount of pigment may be contained in these layers. The coating amounts of the water resistant layer and the back coat layer are preferably 5 to 10 g / m ² and 5 to ²⁰ g / m ^{2 in} dry weight, respectively. When the coating amount of each is less than 5 g / m ² , the resulting printing plate material may not have sufficient water resistance and curling prevention effect.

The solvent resistant layer is generally a water-soluble resin having a high solvent resistance such as starch, a cellulose derivative, casein or polyvinyl alcohol, and an emulsion type resin such as an acrylic resin having a high water resistance, SBR or NBR. When,
It is formed of a water resistant agent and a pigment, and the coating amount thereof is preferably 5 to 10 g / m ² . If it is less than 5 g / m ² , the solvent resistance of the obtained printing plate material is insufficient.

The practically sufficient printing durability required for the direct drawing type planographic printing plate material of the present invention is based on the fact that the number of through-printed sheets is at least 500.

[0025]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited by these. In the examples, "parts" and "%" represent "parts by weight" and "% by weight", respectively, unless otherwise specified.

Example 1 A coating solution having the following composition was applied onto a surface of a substrate made of paper which was wet-strengthened and internally sized to give a dry weight of 10 g / m 2.
^It was coated so as to be ² and dried to form a water resistant layer on the image receiving layer side.

The image-receiving layer side water-resistant layer forming coating solution composition Ingredient Weight clay dispersion of (50% solids) 30 parts of emulsion type acrylic resin (40% solids, 50 parts trademark: ARON A-104, Toagosei Kagaku Kogyo Co., Ltd.) SBR (solid content 50%, trademark: Nipol LX-415, 40 parts, manufactured by Nippon Zeon Co., Ltd.) Water 50 parts Cobb size of this water resistant layer is determined according to JIS P-8140.
It was 0.5 g / m ² when measured in accordance with.

Next, a back coating layer was formed by coating the back surface of the paper substrate with a coating solution having the following composition so that the dry weight was 15 g / m ² and drying. Backcoat coating composition was Composition Ingredient Weight clay dispersion (50%) 60 parts emulsion type acrylic resin (45% solids, 45 parts trademark Bonron S-482, manufactured by Mitsui Toatsu Chemicals) 50 parts of water

Next, a coating solution having the following composition was coated on the water resistant layer so that the dry weight was 10 g / m ² .
After drying, an image receiving layer was formed. Ingredients The composition of the image receiving layer coating liquid Weight zinc oxide dispersion (50%) 160 parts of an emulsion type acrylic resin (40% solids, 50 parts trademark: ARON A-104, manufactured by Toagosei Chemical Industry) Antistatic Agent (Trademark: Nopcostat 092, 0.5 part, manufactured by San Nopco) Methanol 2 parts Water 37.5 parts

A copy machine (trademark: Fuji Xerox) was placed on the image-receiving layer of the lithographic printing plate material thus prepared.
5026) was used to transfer the image, and the plate was prepared by a conventional method. In this plate-making process, almost no fog in the non-image area due to toner scattering was observed. Also, 5 cm x 5 cm
When the image density of the solid image portion of the toner was measured using a Macbeth reflection densitometer, it was 1.24.
It shows that the transfer efficiency of the toner is good. This printing plate was desensitized with a cyan-based etchant made by Itek Co., Ltd., and then printed using an offset printing machine.There were few print stains, especially print stains due to toner scattering fog, and printing durability. The force was over 1000 sheets.

A thermal transfer printer (trademark: Report 95
G, manufactured by Toshiba), there was little ink transfer from the ink ribbon to the non-image area. This printing plate was desensitized with a cyan-based etchant manufactured by Itek Co., Ltd. in the same manner as described above, and then printed using an offset printing machine. No stain due to ink transfer was observed.

Example 2 A support having the same water resistant layer and back coat layer as in Example 1 was used, and a coating solution for a solvent resistant layer having the following composition was dried on the water resistant layer in a dry weight of 7 g / It was coated so that it had a surface area of m ² , and this coating layer was cured at 50 ° C. for 72 hours to form a solvent resistant layer.

[0033] Ingredient composition of solvent layer forming coating liquid Weight clay dispersion (50%) 20 parts casein (10% aqueous solution) 100 parts emulsion type acrylic resin (trademark: ARON A-104) 25 parts glyoxal 5 parts 25 parts of water

Next, a composition having the following composition was prepared and dispersed by a sand grinder to prepare a solvent dispersion type coating solution for forming an image receiving layer, which was dried on the solvent resistant layer. Of 10 g / m ² to form an image receiving layer.

The image-receiving layer composition Ingredient Weight zinc oxide coating solution for forming (TM: SAZEX # 2000, manufactured by Sakai Chemical Industry Co.) 85 parts Acrylic resin (Trademark: ACRYDIC A-405, 28 parts of solid content: 50 wt%, manufactured by Dainippon Ink and Chemicals, Inc.) Antistatic agent (trademark: Nopcostat SNA-2, 1 part manufactured by San Nopco) Methanol 3 parts Toluene 83 parts

The obtained lithographic printing plate was subjected to plate making by the same method as in Example 1 using a copying machine. As a result, the fog in the non-image area due to toner scattering was very small and the density of the toner image was 1.28. The toner transfer efficiency was also good. Also, in plate making by a thermal transfer printer, ink transfer from the ink ribbon to the non-image area was small. When the obtained printing machine was etched by a conventional method and then printed using it, the printing stain was small and the printing durability was 1500 sheets.

Comparative Example 1 A printing plate was prepared in the same manner as in Example 1. However, the image receiving layer contained no antistatic agent. The obtained lithographic printing plate was subjected to plate making with a copier in the same manner as in Example 1,
Fogging in the non-image area due to toner scattering was remarkable. When this printing plate was used for printing, the printing durability was 1000.
Although the number of sheets was more than one, stains on the print were found due to toner fogging. Also, in plate making by a thermal transfer printer, ink transfer from the ink ribbon to the non-image area was observed, which caused printing stains.

Comparative Example 2 A printing plate was prepared in the same manner as in Example 1. However, in the image receiving layer, a coating solution having the following composition was applied so that the content of the antistatic agent was 8%, the dry weight was 10 g / m ² , and the image was dried. A receptive layer was formed.

[0039] Ingredient composition of the image-receiving layer coating liquid Weight zinc oxide dispersion (50%) 160 parts of an emulsion type acrylic resin (40% solids, 30 parts trademark: ARON A-104, Toagosei Co., Ltd. ) Antistatic agent (trademark: Nopcostat 092, manufactured by San Nopco) 8 parts Methanol 5 parts Water 47 parts

When the obtained lithographic printing plate material was subjected to plate making by a copying machine in the same manner as in Example 1, the toner fogging was small, but the toner transfer efficiency to the image area was lowered, and the density of the toner image was 0. It was 64. In printing using this printing plate, printing stains were observed, images were not reproduced, and printing durability was only 30 sheets. Further, in plate making with a thermal transfer printer, ink transfer from the ink ribbon to the non-image area did not occur, but desensitization was insufficient and printing stains occurred.

Comparative Example 3 A printing plate was prepared in the same manner as in Example 2. However, a water-soluble antistatic agent was used instead of the alcohol-soluble antistatic agent used in the image receiving layer. That is,
A coating solution having the following composition was applied so that the dry weight was 10 g / m ² , and dried to form an image receiving layer.

The image-receiving layer composition Ingredient Weight zinc oxide coating solution for forming (TM: SAZEX # 2000, manufactured by Sakai Chemical Industry Co.) 85 parts Acrylic resin (Trademark: ACRYDIC A-405, 28 parts of solid content: 50% by weight, manufactured by Dainippon Ink and Chemicals, Inc. Water-soluble antistatic agent (trademark: VERSA-TL 125, 1 part manufactured by Kanebo NSC) Toluene 86 parts

In the lithographic printing plate obtained, the antistatic agent was not uniformly dispersed in the image receiving layer. When this printing plate material was made by a copying machine in the same manner as in Example 1, the fog in the non-image area due to toner scattering was as large as in Comparative Example 1. Further, in plate making by a thermal transfer printer, ink transfer from the ink ribbon to the non-image area was observed, which appeared as print stains.

Comparative Example 4 A printing plate material was prepared in the same manner as in Example 2. However, conductive zinc oxide was used instead of the antistatic agent and zinc oxide used in the image receiving layer. That is, a coating solution having the following composition was applied to a dry weight of 10 g / m ² and dried to form an image receiving layer.

The image-receiving Ingredient composition layer forming coating liquid Weight electroconductive zinc oxide (trademark: FX-S, Honjo Chemical Co.) 85 parts Acrylic resin (Trademark: ACRYDIC A-405, 28 parts of the solids content : 50% by weight, manufactured by Dainippon Ink and Chemicals, Inc.) Toluene 86 parts

When the obtained lithographic printing plate material was subjected to plate making with a copying machine in the same manner as in Example 1, the fog in the non-image area due to toner scattering was as large as in Comparative Example 3. Further, its desensitizing ability is lower than that of the printing plate material of Example 2,
Printing stains are more likely to occur. Further, in plate making by a thermal transfer printer, the effect of preventing electrification was not exhibited, and ink transfer from the ink ribbon to the non-image area was observed, resulting in printing stains.

[0047]

INDUSTRIAL APPLICABILITY The direct drawing type lithographic printing plate material of the present invention has a non-image area due to toner scattering when compared with the conventional direct drawing type lithographic printing plate material when plate making is carried out by an electrostatic transfer type copying machine. Fogging is significantly reduced, stains during printing are extremely small, and printing durability is excellent. Further, when the direct-drawing lithographic printing plate material of the present invention is subjected to plate making by a thermal transfer printer, ink transfer from the ink ribbon to the non-image area is small, and stains are reduced during printing. Therefore, the direct drawing type lithographic printing plate material of the present invention is an electrostatic transfer type copying machine,
It is possible to easily make a plate with a thermal transfer printer,
It can be used advantageously in the fields of office printing and light printing.

Claims (1)

[Claims] 1. A water resistant support and an image receiving layer formed on the water resistant support, wherein the image receiving layer is zinc oxide, a binder resin, and 0.1 to 5% alcohol. A direct drawing type lithographic printing plate material containing a soluble antistatic agent.