Technical problems of offset printing plate

In the packaging and printing industry, sometimes there are some technical problems related to offset printing plate. Today, the editor of China paper industry network takes you from offset printing to introduce the relevant problems and solutions in detail.

What are the main causes of the dirty printing plate?

(1) Causes: insufficient exposure, poor transparency of positive pictures, aging of light source, processing method: re production of positive pictures, proper adjustment of exposure time: retest with gray ladder, extend exposure time, or replace light source lamp.

(2) Reason: the glass of the plate printing machine is a little dirty, and the positive picture is attached with adhesive tape. Treatment method: use glass cleaner and film cleaner to remove dirt.

(3) Cause: during development, the development is poor due to the blister attachment, and the spray hole of the developing liquid bubbles due to blockage. Treatment: eliminate the foaming cause: the development liquid should be cleaned and sprayed.

(4) Reason: hands are not clean (fingerprint stains) when PS version is used. Treatment: keep the mouth and the back part during operation.

(5) Reason: the glue is thin. Treatment method: increase the concentration of glue solution.

(6) Cause: the rubber layer falls off (when the rubber layer is not dry, it should be put back and stored repeatedly). Treatment: do not keep it in high temperature and high humidity.

(7) Reason: after the plate making is finished, it shall be kept in high temperature and high humidity condition. Treatment method: do not keep it in high temperature and high humidity condition.

(8) Cause: the concentration of the developer is too low, and the development is not complete. Treatment method: adjust the developing solution to the standard concentration.

2. how to improve the development quality of PS version of Yangtu?

The dilution rate of the developer shall be in accordance with the proportion specified by the manufacturer of PS, and the small sample version shall be used (the small PS version after exposure with Fuji gray ladder ruler can be used to measure the concentration of the developer.) The concentration of the developing solution was managed.

3. in the process of printing, the blank of the printing plate is often dirty. How to solve it?

(1) Reason: when printing stopped, the plate did not rub the protective adhesive. Treatment method: wipe the protective adhesive.

(2) Reason: the blank part of the plate is not wet enough. Treatment method: increase water amount properly.

(3) Cause: the emulsion is dirty. Treatment method: adjust the balance between ink and water bucket liquid, or replace ink and water bucket liquid.

4. why the film collage publishing materials are prone to be false?

(1) Reason: the collage of the positive picture film is not proper. Processing method: Collage the film 3 mm away from the image part.

(2) Cause: the concentration of developer is too high. Treatment method: adjust the developing solution to the standard concentration.

Komentarze