When it comes to the production of plastic packaging bags, it is not only the decoration of its surface, but also the ability of combining commodity’s information spreading with visual aesthetics.Therefore,dry offset printing and waterless offset printing are used in usual. Generally, we make selection between them according to the use environment and productions. So,what’s the difference between them?

Generally,dry offset printing refers to a method of indirect printing on the lithographic press using letterpress instead of lithography. It is a printing method which is the combination of letterpress and offset printing. It is named of dry offset printing because the letterpress does not use water. The disadvantage of dry offset printing is that it can not print completely when the dot is less then 40%. Because very fine needle dot will infiltrate to the blanket which will make printing dot gain.

As to the waterless offset printing, it is thin letterpress plate. When it works, the frontal convex ink on plate will transferred to the blanket cylinder, and then transferred from the blanket to printing materials. So this printing method has the advantages of high press life, bright ink color(letterpress), and can be printed on hard plastic materials( lithography indirect printing).

Waterless offset printing is a great revolution to lithography printing, the key to this revolution is the lithography technology and printing ink reform.Lithographic printing without water is a fundamental change in lithographic printing.Because it does not use water, it not only simplifies the operation of the printing process, but also greatly reduces many problems caused by water, and because of its better ink viscosity than ordinary ink, it is easy to pull paper wool, stack. Because there's no water, the paper has more static electricity, and so on.