Working principle of screen printing machine:
The screen printing machine belongs to the more representative printing equipment in the stencil printing machine, and its printing plate is a silk screen which is woven by materials such as silk and has a crisscross pattern with distinct warp and latitude.
We have produced a variety of screen printing machines such as plane, curved surface, forming, printing and dyeing, printed circuit and new type rotary. Among them, the speed and productivity of the new rotary screen printing machine are relatively high. Its characteristic is that the screen is installed on the cylinder of the roller printing machine, and the ink is poured into the cylinder.
When the machine is working, the cylinder rotates, and the rubber squeegee quickly prints the pattern onto the printed matter.
Besides silk, nylon wire, copper wire, steel wire or stainless steel wire can also be used to make wire mesh. The principle of stencil printing applied to screen printing machines originated from ancient stencil printing.
There are many forms of stencil printing, such as transcript printing, hollow printing and silk screen printing.
Screen printing was initially performed manually, at the time there was only one plate holder, one screen plate and one template. It was not until the 1950s that screen printing was mechanized and automated.
The cylinder screen printing machine has a large amount of ink during printing. It is suitable for printing thick printed materials. It can be printed on a variety of paper, glass, wood, metal, ceramic, plastic or cloth. A variety of inks, including conductive Metallic ink.
Printing principle of gravure printing machine:
The main feature of the gravure printing machine is that the graphics and text on the printing plate are concave, and the blank part is convex, which is exactly the opposite of the layout structure of the relief printing machine. When the machine is printing monochrome, the printing plate is first immersed in the ink tank and rolled, and the entire printing plate surface is coated with the printing mechanical layer of ink.
Then, the ink layer belonging to the blank part on the surface of the printing plate is scraped off, the convex part forms a blank, and the concave part is filled with ink. The deeper the concave part, the thicker the ink layer. The machine transfers the ink in the recessed part to the printed matter by the action of pressure to obtain the printed matter.
When printing multi-color, the overprint method or indirect partial ink coating method is used to make the inks of various colors be distributed on the relevant parts of the printing plate surface as needed. The basic printing principle of multi-color printing is the same as that of printing monochrome. There are two main types of printing plates used in gravure printing machines, one is photogravure, that is, photocopying plate; the other is engraving plate. The engraving of the engraved version includes manual engraving, mechanical engraving and electronic engraving.
Basic principles of stencil printing:
The principle of stencil printing is that under the action of a squeegee, the screen printing ink leaks from the screen mesh to the printed substrate, because the non-graphic part of the printing plate is blocked by the screen mesh , Ink can not leak to the substrate, so as to complete the printing of printed matter.
All the ink layers on the printed matter have a three-dimensional effect, such as bottle and can, curved surface and general circuit board printing, multi-hole printing.
The layout is a mesh or a thin layer with a certain elasticity, and the graphics and text are partially transparent. The ink or color material is missed on the substrate through the printing plate. . However, it is still customary for people to classify it as special printing.
There are 4 types of stencil printing, type printing plate, transcription stencil printing, type printing stencil printing and screen printing. They have the characteristics of light equipment, simple process and easy operation, and are widely used.
①Type version. Engrave text or graphics on wood chips, cardboard, metal or plastic sheets to make a hollow printing plate, and use brushing or spraying to make the color material print on the substrate through the printing plate. This is one of the oldest techniques. Judging from the unearthed ancient printed fabrics, the Chinese version has been adopted in spring and autumn. Due to the simplicity of the method, it was still used by the people in the 1980s.
② Transcribe the stencil. Plate making by handwriting method, the earliest is to use a brush dipped in dilute acid (such as sulfuric acid) to draw graphics on the porous paper coated with gelatin, dilute acid will dissolve the gelatin film, exposing porous fibers, forming a porous version, called the brush transcription version. Because the edges of the graphics are easily corroded by acid and the printing accuracy is poor, this method has been rarely used after the stylus transcription version appeared. The stylus transcript is a printing plate made of wax paper on a textured steel plate with a stylus. The scratched part of the wax paper can penetrate ink. This method was invented by T.A. Edison in 1886. Because the handwriting of the transcription varies from person to person, it is far less clear than the typewriting typeface invented later, and the application has been gradually reduced. The water-washing transcript is to use a pen to dip the water-soluble glue to write on the porous paper, and then coat a layer of water-insoluble glue film on the paper, and then wash with water to dissolve the writing part to form a hole plate.
③ typing stencil. The typewriter is used to print the movable type on the wax paper, and the impact of the movable type causes the wax paper to form an ink permeable plate. The practical English typewriter model was first produced in the United States in the 1980s. The Chinese typewriter was first created during the Taisho period in Japan (1912 to 1926), and it was rapidly popularized after the Second World War. The development of computer word processing technology and office automation system has gradually replaced stencil printing.
④Screen printing. Since the 1950s, it has become the mainstream of stencil printing.