The method of manufacture of offset printing plates

 

(57) Abstract:

Use: in the manufacture of offset printing plates. The inventive plate from triacetylcellulose film with a photosensitive layer on the basis of diazoma copy and take with water. Then the surface of the cover plate 2-8% solution of water-soluble polymer is polyvinyl alcohol or carboxymethylcellulose, or ethylene glycol, with the addition of 2-8% water-soluble inorganic substances - sodium chloride or sodium hydroxide.

The invention relates to the printing industry and can be used in the manufacture of offset printing plates on triacetylcellulose plate.

A known method of manufacturing a photomechanical print forms (Bruises N. I. Technology of production of photomechanical printing plates. M. Book, 1966, S. 313), which uses film materials obtained in a known manner. The disadvantage of this method is the fact that printing plates have a small length-prone and ill remove surface contamination.

A known method of manufacturing a shape on the plate, made of triacetylcellulose film, and the spacing elements are treated with solutions of strong alkalis (caustic soda, caustic potash) for 1.5 to 2.0 hours hydrophilic surface triacetylcellulose film is applied photosensitive layer on the basis of diazoma. After copying and processing get the printing elements.

The length of the forms produced in a known manner on triacetylcellulose plate, only 2-3 thousand impressions, and the product quality is satisfactory. A disadvantage of the known methods of producing forms on triacetylcellulose plate is the fact that it does not provide printed forms properties, precluding strong and difficult to remove surface contamination (Nikanchikov E. A. Popov, A. A. the Technology of offset production. H. I. Production of printing forms. M. Book, 1978).

The essence of the proposed method is that after copying and processing of offset printing plates on triacetylcellulose film its surface is covered with 2-8% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 2-8% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, which reduces the degree of surface contamination and allows for the occurrence of contamination on the sample is the target water-soluble polymer, for example, polyvinyl alcohol or carboxymethylcellulose, or ethylene glycol, with the addition of 2-8% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, and 15-35% isopropyl alcohol.

The method is as follows.

Example 1. After copying and processing water offset printing plates on triacetylcellulose film its surface is covered with 2% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 2% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, which significantly reduces the extent of surface contamination and provides ease of its removal on a whitespace elements offset printing plate by wiping its surface 2% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 2% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, and 15% isopropyl alcohol.

Example 2. After copying and processing water offset printing plates on triacetylcellulose film her poetically, or ethylene glycol, with the addition of 5% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, and with the appearance of dirt on a whitespace elements offset printing plate as in example 1, the surface can be wiped with a 5% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 5% water-soluble inorganic substances such as sodium chloride or sodium hydroxide, and 25% isopropyl alcohol.

Example 3. After copying and processing water offset printing plates on triacetylcellulose film its surface is covered with 8% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 8% of a water-soluble inorganic substances such as sodium chloride or sodium hydroxide, and with the appearance of dirt on a whitespace elements offset printing plate as in example 1 and 2, the surface can be wiped with a 8% solution of water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose, or ethylene glycol, with the addition of 8% of a water-soluble inorganic substances, for example the printed form, including copying and manifestation water plate of triacetylcellulose film with a photosensitive layer on the basis of diazoma, characterized in that after developing the water surface of the cover plate 2 8% solution of water-soluble polymer is polyvinyl alcohol or carboxymethylcellulose, or glycol with the addition of 2 to 8% of a water-soluble inorganic substances sodium chloride or sodium hydroxide.

 

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