The printing press（三）
Letterpress is the oldest and most popular type of printing. The embossed part of an image or text does not accept ink. When pressed against the paper, ink is printed on the paper. Printing plate material mainly: movable type, lead, zinc plate, copper plate, photosensitive resin plate, etc. Some books and periodicals, bills, envelopes, business cards, etc. are still in relief printing; Special processing such as: bronzing, silver, embossing, etc., generally also use letterpress printing.
Lithography is the most common and widely used method of printing. Image and non-image in the same plane, the use of water and ink now mutually exclusive principle, the text and text part of the ink does not accept water, non-text part of the opposite. The printing process USES the indirect method, the image is first printed on the rubber drum, the picture and text from the positive to reverse, and then the rubber drum pictures and text transfer to the paper. Picture album, picture magazine advertising samples, calendar, etc. Can be used in this way of printing.
Gravure printing is the opposite of letterpress printing. The concave part of text and image carries ink under the concave part of the page.
The shade of printing is related to the depth of intaglio, the depth is thick, shallow is light. Because the intaglio printing ink is different, so the printing lines have a protruding feeling. Coins, stamps and securities are printed in intaglio. Gravure printing is also suitable for plastic film and silk printing. The cost of gravure printing is high because of its long time and complicated process.
Hole printing USES silk cloth, metal and synthetic materials such as silk screen, wax paper, etc., as the printing plate, the picture and text part is hollowed-out into fine holes, non-picture and text parts are protected by printing materials, the plate is close to the substrate, with a scraper or ink roller to make ink permeate to the substrate. Screen printing can be printed not only on the surface of the substrate but also on the surface of the substrate, colorful, durable. Suitable for printing labels, bags, T-shirts, plastic products, glass, metal utensils and other objects.
Flexible printing is a kind of printing method commonly used in packaging. Flexo printing is the process of producing a projection of the desired image image on a plate or polyester material. The amount of ink transferred to the plate is controlled by the anilox roller. The printing surface is in contact with the printing material during rotation, thus transferring the image and text.