Plastic packaging bag plate making requirements – packaging bag printing

Plate making is an indispensable process before the printing of various color printing composite bags. It is a general term for copying the original into a printing plate. There are the most factors affecting the quality of the printing plate in plate making, mainly including the concentration of the developer, the temperature and time of development, the circulation and stirring of the developer, and the degree of fatigue and decay of the developer. Improper operation often results in blank printing plates, missing dots, and blur images. [Packaging bag printing] (1) There are three reasons for the small dots, small characters and thin lines to be washed out: the back exposure time is not enough, and it is necessary to consider increasing the back exposure time; the main exposure time is not enough, the main exposure time can be increased; color printing packaging If the washing time is too long or the pressure of the brush is too large, it is necessary to shorten the washing time and adjust the pressure of the brush; (2) The reason for the inconsistency of the washing depth of the same printing plate is: the printing machine is too hot, carefully check the ventilation and cooling Whether the system is faulty; the intensity of the printing lamps is uneven or the opening is not synchronized, and all the lamps are replaced at the same time; the washing brushes are not parallel or the action is unbalanced, and the pressure and levelness of the washing brushes can be adjusted; (3) Field, text The reason for the failure of cracking when moving and bending after plate making is: the time of main exposure and back exposure is too long, which can uce the time of main exposure and back exposure; Insufficient exposure, check whether the lamp tube is damaged or aged; (4) There are two reasons for the loss of small dots during printing: the main or back exposure is insufficient, and the main exposure or back exposure time can be increased; the original design exceeds the reproduction capability of flexo printing. Improve the design of the original to make it suitable for the technical scope of color printing packaging and flexo printing; (5) The reason for the blockage of the blank part of the printing plate is: the back exposure time is too long, and attention should be paid to correctly control the back exposure time; On the premise of packaging small text and thin lines, the main exposure time should be shortened as much as possible; if the plate and film are in poor contact, the vacuum system should be guaranteed to work normally, and the air between the plate and the film should be driven out by rollers; There are five reasons for the wave shape: insufficient back exposure, increase the time of back exposure; insufficient main exposure, increase the time of main exposure; insufficient drying time, increase the drying time; if the washing water is not fresh, replace it with a fresh washing plate Water; the washing time is too long, adjust the washing time; (7) The main reasons for the incomplete hardening of the bottom of the printing plate are: insufficient back exposure, increase the back exposure time; incomplete washing, residual unhardened resin remains, check the hair (8) If the image is blur, two points must be paid attention to: if the film is defective, carefully check whether the color printing package image on the film is clear; if the offset film is wrongly used for flexo printing, it must be remade. Qualified flexo film. Vacuum packaging bags, tea packaging bags