JPS6232093A - Original plate for electrophotographic planographic printing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a lithographic printing original plate of a type that is made by electrophotography.

As a conventional lithographic printing method, a toner image is formed on the surface (photoconductive layer surface) of an electrophotographic lithographic printing original plate by electrophotography, and after fixing, the non-image area is treated with a desensitizing liquid to form a printing plate. A widely used method is to print this on a lithographic printing machine. Conventionally, as an electrophotographic lithographic printing original plate used in this method, a photoconductive layer containing an inorganic photoconductive substance to an insulating resin dispersion is provided on one side of a paper support, and 1) a water-soluble resin and a cationic resin are disposed on the opposite side. Alternatively, it is known to have a 7979 layer mainly composed of an anionic conductive agent, or 2) an anionic emulsion synthetic resin and an anionic conductive agent.

Further, for the purpose of improving printing durability, efforts have been made to use a paper support that has been treated with moisture resistance, and furthermore to interpose an adhesive layer or a precoat layer between the support and the photoconductive layer. As a result, in terms of printing durability, the original plate has a considerable number of 4Is, but in the case of the original plate (1), the back layer has weak water resistance, so the dampening water dissolves the pack layer during lithographic printing, and the printing machine In addition, in the case of the original plate (2), the conductivity of the adhesive layer is low or insufficient, making it difficult to obtain stable and good images from low humidity to high humidity. Ta.

Purpose An object of the present invention is to provide an electrophotographic lithographic printing original plate free from the above-mentioned drawbacks by improving the water resistance of the pack layer and the conductivity at low humidity.

Structure: The electrophotographic lithographic printing original plate of the present invention is provided with a photoconductor layer containing an inorganic photoconductive material or an insulating resin dispersion on one side of a paper support, and a nonionic or cationic emulsion type synthetic resin or a cationic emulsion type synthetic resin on the opposite side. It is characterized by having 7972 layers mainly composed of a conductive agent and calcium carbonate.

The present invention is characterized in that the 7972 layer 8 is composed of a combination of a specific resin, a conductive agent, and an inorganic pigment.

The nonionic or cationic emulsion-type synthetic resin used in the six layers of the present invention is acrylic resin, vinyl acetate resin, polyester resin, etc., which is produced by emulsion polymerization using a nonionic surfactant or a cationic surfactant. Resins, sunalene resins, vinyl chloride resins, urethane resins synthesized as 80/AN type resin emulsions are used. These have a minimum film forming temperature of 120 to 60
℃ is suitable. If this temperature is lower than 120°C, the 7972 layer tends to block, and if it is higher than 60°C, the continuous film strength S of the A-tack layer becomes poor.

The above-mentioned emulsion type synthetic resins are available as commercial products, such as those listed below. Note that MFT within 0 is the lowest film forming temperature.

(1) /Nionic synthetic resin emulsion Vinyl acetate resin emulsion; Showa Kobunshi KK Polysol S-5 (MFT15°C)
, Polysol S-5-50 ('T2°C).

I Reseal S-61 (5-61 (℃), Polysol P8
(MFT 12°C), Polysol 2NS (MFT.

13℃).

Vinyl acetate/acrylic acid ester copolymer resin emulsion; Polysol VA-100 manufactured by Showa Kobunshi ■ (MP?5℃)
, Polysol 747 L (MP'TO"C) ethylene/vinyl acetate copolymer resin; Polysol RYAL-100 (MF72 manufactured by Showa Kobunshi ■)
℃) Acrylic resin emulsion; Showa Kobunshi Co., Ltd. 4 reseal AP-610 (MPTO ℃)
,/Reseal AY-901 (MFTI 11℃), lReseal AP-612 (MPTO℃) Movinyl L-385 manufactured by Hoechst Synthesis ■ (MPT 19℃)
) (2) Cationic synthetic resin emulsion Vinyl acetate resin emulsion; Movinyl L-5030F manufactured by Hoechst Synthesis ■! (MFT
18°C) Acrylic resin emulsion; Bonco manufactured by Dainippon Chemical Industries KK) 810-54 (MF
T 20℃), Boncourt 8FC-300 (MFT50
-60°C).

Toagosei Kagaku KK Aron HD5010 (MP'l'O
C) Aron HD5020 (MFT50C) Conductive agents include cationic conductive agents and anionic conductive agents, and cationic conductive agents are superior in terms of conductivity in a low-humidity atmosphere. Therefore, in the present invention, a cationic conductive agent is used.

As the cationic conductive agent, for example, polyvinyl 47
v.trimethyl-quaternary ammonium chloride (A commercially available product is, for example, BOR77 manufactured by Dow Chemical Company, USA).

) can be mentioned.

The amount used is α05~O per 1 part by weight of emulsion type resin.
, S parts by weight are appropriate. The lid of the cation conductive agent is 0.0
If it is less than 5 parts by weight, the conductivity of the pack layer will be insufficient and 0.
．． If the amount is 5 parts by weight or more, the water resistance of the pack layer will be insufficient and the printing plate will stick to the cylinder of the printing press during or after planographic printing.

Calcium carbonate used in the pack layer is commonly used in the paper manufacturing industry and is easily available as a commercial product.

An example of a commercially available product is Netx G1PC1 Silno? -w
, pcx, Akadama, Whiten, P-30, H, 302,
303, Red 5SB (all of the above are Shiraishi Kogyo n1), etc. The amount used is 0 per part of emulsion type synthetic resin.
．． 2 to 4 parts by weight is preferred. If this amount is less than 0.2[-i parts, the pack layer will easily block, and 4
If the amount is more than 1 part by weight, the continuous film properties of the thick layer will be poor.

On the other hand, the photoconductive layer is composed mainly of an inorganic photoconductive substance such as zinc oxide or cadmium sulfide dispersed in an insulating resin such as silicone resin or acrylic resin, just as in the conventional case. Other sensitizing agents may be added to the photoconductive layer.

In the present invention, in order to further improve printing durability, the support and the light guide 1 are
It is possible to provide an adhesive layer or a precoat layer between the 11th layer and the 11th layer.

The present invention will be explained below using practical examples.

Example 1 A water-based paint containing 100 parts by weight of clay, 40 parts by weight of -lipinyl alcohol, and 10 parts by weight of melamine resin was applied and dried on one side of a paper support made of moisture-resistant treated paper weighing 110 t/m''. A precoat layer with an adhesion amount of 12 t/- was provided.

Next, 2.63 parts by weight of nonionic acrylic resin emulsion (-Reseal AY-901. Minimum film forming temperature 18°C, resin content 38%, Showa Kobunshi IQCIII), calcium carbonate (Tunex E, manufactured by Shiraishi Kogyo ■) 50% aqueous dispersion zO parts by weight, cationic conductive agent (I lipinylbenzyl trimethyl quaternary ammonium chloride), 33.
5ts aqueous solution, ECR77, manufactured by Dow Chemical Company, USA)
A water-based paint consisting of 0.6 parts by weight and 1 part by weight of water was applied to the opposite side of the support from the precoat layer and dried to form a 79-layer coating with a coating weight of 7 m''.

Next, an organic solvent-based paint containing 100 parts by weight of zinc monoxide, 20 parts by weight of an oil-soluble acrylic resin, and 0.08 parts by weight of a sensitizing dye (Rose Bengal) using the French method was applied onto the pre-coat layer and dried to determine the amount of adhesion. An original plate for electrophotographic lithographic printing was prepared by providing a photoconductive layer having a particle diameter of 25 f/-.

The surface resistivity Pa of the pack layer of this product is lO'C, 30
Even in a low humidity environment of 4RH, it exhibited excellent conductivity of less than IXI O'''Ω'Ω.

In addition, using this lithographic printing original plate, plate making was performed using an electrophotographic printing machine (AP-7000, manufactured by IJ Coco).
When printed, 10℃ 30% P, U low humidity to 30℃
Stable and good images were obtained even in a high humidity atmosphere of 904RH, and the printing plate did not stick to the cylinder of the printing press even after printing 1000 sheets.

Next, as a comparative example, (1) when an anionic acrylic Mm fat emulsion was used instead of a nonionic acrylic resin emulsion, 7972 layers of paint gelled and could not be applied; (2) a nonionic acrylic resin emulsion (3) When using starch or polyvinyl alcohol instead, the printing plate sticks to the cylinder of the printing press after printing, and (3) When clay is used instead of calcium carbonate, small aggregates occur in the A-layer paint. I couldn't apply it properly.

Example 2 Nonionic acrylate ffJ as water-based paint for pack layer
4-fat emulsion (Polysol AP-610, minimum film forming temperature 0°C, resin content 60%.

Reactive type, manufactured by Showa Kobunshi ■] 167 parts by weight, 50% aqueous dispersion of charcoal-brewed calcium (PC, Shiraishi Kogyo KK School) zOi
Quantity parts, cationic conductive agent (30% aqueous solution of polyvinylbenzyl trimethyl quaternary ammonium chloride) α
7 parts by weight, 80% aqueous solution of melamine resin (Smithys 6
13, Sumitomo Chemical Co., Ltd.) 0. A mixture consisting of 25 parts by weight and 0.6 parts by weight of water was used, and the amount of adhesion was 7 tons. Example 3 A cationic cenyl acetate resin emulsion was used instead of the nonionic acrylic resin emulsion in the water-based paint for hanging the /fn layer. (Movinyl L-50301, minimum film forming temperature 18
A lithographic printing original plate was prepared in the same manner as in Example 1, except that the temperature was 50° C., the resin content was 50 ml, and Hoechst synthetic KLI4) io parts by weight were used.

Example 4 Cationic acrylic resin emulsion (Bonco) 8FO-300, minimum film forming temperature 50 instead of nonionic acrylic resin emulsion in the water-based paint for the layer
A lithographic printing original plate was prepared in the same manner as in Example 1, except that the temperature was -60°C, the resin content was 40 inches, and 25 parts by weight (manufactured by Dainippon Ink and Chemicals KK) was used.

Next, the lithographic printing original plates obtained in Examples 2 to 4 were tested in the same manner as in Example 1. As a result, stable and good image quality was obtained in low humidity to high humidity atmospheres, and even after printing was completed. There was no sticking to the machine cylinder.

Effects As described above, in the electrophotographic lithographic printing original plate of the present invention, since the pack layer is composed of a specific emulsion type synthetic resin, a conductive agent, and an inorganic pigment, the water resistance and conductivity at low humidity of the pack layer are improved. As a result, it does not stick to the cylinder of the printing press after printing, and stable and good images can be obtained in both low and high humidity environments.

Claims (1)

[Claims] 1. A photoconductive layer containing an inorganic photoconductive substance or an insulating resin dispersion is provided on one side of a paper support, and a nonionic or cationic emulsion-type synthetic resin, a cationic conductive agent, and calcium carbonate as main components is provided on the other side. An original plate for electrophotographic planographic printing provided with a back layer.