Printing overprint inaccurate phenomenon and solution

In the printing process, the printed matter is easily overprinted. Overprinting is the basis for achieving color reproduction, and it is also the key to guarantee the quality of printed products. When evaluating the quality of printed products, overprint accuracy and color standards are equally important. Overprinting of inaccurate images is fuzzy. You can directly use printed sheets to make judgments. Generally, printed sheets have regular lines such as register lines and angle lines. Is it accurate?

From the point of view of the printing press, there is a strict transfer relationship between paper in the process of conveying paper, regular parts, delivery dents, transfer drum to delivery ribs, and its essence is to guarantee the accurate and accurate conveyance of the paper. Do not allow paper to run out of control. This is summarized in one sentence: “The paper must always be properly and firmly controlled during the paper path transfer, so that the overprinting accuracy can be guaranteed.”

Now focus on the process from the perspective of overprinting is not allowed to fault, overprinting can not be directly used to judge the printed sheet, this type of overprinting can be divided into three categories: 1. Post-printed image location equidistant to one side. This failure is caused by the non-corresponding relationship between the plate image and the paper position. 2. The unevenness of the position of the image after printing. This may be caused by crosshairs registering on one side and inaccurate sets on the other side. This type of overprinting is not allowed to be caused by the inconsistency between the image size on the paper and the newly printed image size. 3. Partial image overprinting is not allowed. This situation only occurs on a small area of ​​the printed sheet. When such failures are serious, the paper wrinkles often appear.

The reasons for the above overprinting are also three types, that is, the improper adjustment of the printing press, the deformation of the paper, and the improper lining of the roller. It also requires that we have corresponding solutions: 1. Press the technical instructions to operate the printing equipment; 2. Set up a special printing paper library, the printing paper is preferably the current use of the current; 3. In strict accordance with the technical data to replace the printing supplies (package Lining, plate, PS plate, blanket, etc.) As long as the master of the printing worker pays attention to the accumulated experience and pays attention to the operation method of the printing press, it is very easy to resolve the overprint due to the process.