1. printing process flow
Before packaging and molding, a series of printing tasks are needed:
In order to improve the quality of printing and production efficiency, before printing, attention should be paid to checking the content of the design manuscript, the completeness of the text and lines, the inspection of the plate, the color mark and the completeness of the various printing and cutting lines. Only in this way can we improve the production efficiency and ensure the smooth completion of printing.
Different packaging materials will have different printing processes. As paper packaging materials are the most widely used in real life, the printing process of packaging materials is taken as an example to explain the related knowledge of printing process.
2. packaging and printing process
There are many methods of paper packaging printing, different methods, different operations and different printing effects. The traditional printing methods are mainly divided into the following four categories:
(1) letterpress printing
The letterpress is printed in the printing plate, which is higher than the non graphic part, and the ink on the ink roll can only be transferred to the graphic part of the plate, but not the ink in the graphic part, thus completing the printing of the printed matter.
The printed paper has a slight imprint on the back of the print, the line or the edge of the dot is neat, and the ink is shallow in the central part, and it is a protruding print.
(2) intaglio printing
Contrary to letterpress, the graphic part of the printing plate is lower than the non graphic part, forming a groove shape. The ink is covered only in the groove, the printing plate has no ink on the surface, and the paper is overlaid on the plate. The printing plate and the paper are pressurized to transfer the ink from the concave part of the plate to the paper.
Intaglio printing products, with thick ink layer, bright color, and printing plate with high printing rate, printing quality, fast printing speed and so on, so it has been widely used in practice.
The graphic part and the non graphic part of the printing plate are kept flat, and the picture part is covered with a grease film. When printing ink, the picture and text part repels moisture and absorbs ink, and the non graphic part absorbs moisture and forms ink resistance.
The printed product has the characteristics of strong ink color in the center of the lines or dots, irregular edges, poor color reproduction and lack of brilliance.
Hint: because lithographic printing method is simple in operation and low in cost, it has become the most widely used method in printing.
(4) silk screen printing
Screen printing means that under the effect of the scraper extrusion, the ink is leaked from the mesh of the graphic part of the mesh, but the screen mesh of the screen is blocked, and the ink can not be leaked to the printed material to complete the printing of the printed matter.
It has a rich sense of printing quality and strong sense of stereo, and this printing method has not much requirement on the material of the printed material, so it is widely used in various packaging materials.