Encyclopedia of printing: a common inventory of eight special printing methods (2)

Third, electrophotographic offset printing

An offset printing plate is made directly from the manuscript using an electrophotographic platemaking machine, which is called an electrophotographic process.

A zinc oxide paper-based printing plate produced by an electrophotographic process can be directly mounted on an offset printing press. This is used to replace photolithography and zinc plate offset printing within a certain range. It has achieved significant results in terms of shortening the publishing cycle, reducing printing costs, and saving precious materials.

1, the production of electrophotographic version

The method of platemaking with an electrostatic plate-making camera is:

(1) Place the original on the original holder and position it after focusing.

(2) Place the zinc oxide photographic paper in the photographic plate position in the camera dark box.

(3) red. Give the photoconductive layer of zinc oxide sensitized paper a uniform charge. The charging device is also in the camera's black box.

(4) Exposure. The light is irradiated to the photoconductive layer of the charged zinc oxide photosensitive paper, so that the visible light part of the charge disappears, and no light part forms an electrostatic latent image.

(5) Development. The developing powder having a charge opposite to that of the zinc oxide paper-based surface is adsorbed on the charge latent image by the action of attraction of the opposite-electrode charge, and becomes a visible image. This development process takes place in the camera darkroom.

(6) Remove the developed paper plate, vacuum the excess developer powder with a vacuum pump, heat the fuser in the fuser, and then apply a thin layer of protective agent on the surface of the plate.

Each of the above steps amounts to about 5 to 6 minutes.

2. Electrophotographic printing

The prepared zinc oxide paper plate can be printed directly on the plate cylinder of the offset printing machine.

Since the electrophotographic printing plate is a paper-based printing plate, usually only about two thousand sheets can be printed in each plate, and although it has a telescopic phenomenon after processing, it is more suitable for a text printing plate with a small number of printing and a single color.

Fourth, filter printing

Filter printing is commonly known as stencil printing.

The graphic part of the filter plate is composed of holes of different size (or stroke thickness). During printing, the ink is pressed from the hole to the surface of the substrate to complete the printing.

Filter printing includes spray printing and screen printing.

1. Spray printing. The stencil plate is first made by hand. The plate is then placed on the substrate and sprayed or brushed to transfer the ink to the surface of the substrate.

2. screen printing. This is the most versatile printing method used in filter printing. You can print covers of books, copy colored oil paintings, mounting patterns for product packaging, dials for instruments, markings on machines, and radio circuit boards.

The screen-printed printing plate base was originally made of cotton or silk, and was later made of nylon, polyester, polyethylene, stainless steel, copper, and other wire braids, and was stretched tightly over the frame.

The platemaking method of the filter plate can be divided into several types such as manual plate making, photoengraving and electronic plate making.

Photographic platemaking, first coated with photosensitive adhesive on the screen, the photographic or electronic color obtained by translucent Yin picture into a positive picture, close on the screen coated with photosensitive adhesive for printing, and then washed and developed, and dried to make. The part of the printing plate where the photoresist is washed away is the graphic part.

Screen printing was manual printing in the past, and it was gradually printed using screen printing machinery. Screen printing machine screen printing machine and rotary screen printing machine two kinds, according to automatic Cheng Zhi can be divided into semi-automatic and automatic screen printing machine and many other.