Three printing processes are commonly used in the production of plastic bags

1.Gravure printing

The printing of plastic film is mainly based on gravure printing process. The plastic film printed with gravure has the advantages of high printing quality, thick ink layer, bright color, clear and lively pattern, rich picture level, moderate contrast, realistic image and strong three-dimensional sense. Gravure printing requires that the registration error of each color pattern shall not be greater than 0.3mm, and the indicators such as the same color density deviation of the product and the same color deviation of the same batch shall meet the requirements of GB7707-87. Gravure printing plate has strong printing resistance and is suitable for long plate live parts. However, gravure printing also has some disadvantages that can not be ignored, such as complex prepress plate making process, high cost, long cycle, large pollution and so on.

2.Flexographic printing

Flexographic printing mainly uses flexible relief printing ink and fast drying relief printing ink. The utility model has the advantages of simple equipment, low cost, light plate material quality, low pressure during printing, small plate material and mechanical loss, low noise and fast speed during printing. Flexographic plate has the advantages of short plate changing time, high work efficiency, soft, elastic flexographic plate, good ink transfer performance, wide adaptability of printing materials, and the cost of printing small batch products is lower than that of gravure printing. However, flexographic printing has higher requirements for ink and plate materials, so the printing quality is slightly inferior to intaglio printing.

3.Screen printing

During printing, the ink is transferred to the substrate through the mesh of the graphic part through the extrusion of the scraper to form the same graphic as the original.

Screen printing products have rich ink layers, bright colors, full colors, strong covering power, wide selection range of ink varieties, strong adaptability, low pressure during printing, easy operation, simple plate making process and less equipment investment. Therefore, they have low cost, good economic benefits and a wide variety of printing materials.