A company Roland 702 offset press has been used for 5 years, generally printing 90-250g/m2 coated paper and cardboard. A ghost failure was found on the drive side of the print at a time, and the machine was immediately shut down. Based on experience, various influencing factors were checked: (4) Is the pressure of the printing roller and ink roller normal? Upon inspection, the pressure of each reliving water roller and ink roller is normal, and the ink is also normal. (5) Is the gripper loose? After inspection, adjustment, and trial printing, it was found that there were no ghosting problems in the first few sheets. The phenomenon of ghosting was only observed from the 10th sheet, and it was heavy and shallow, indicating that the problem was not on the grippers. (6) Is the front gauge and side gauge normal? After checking the needle position, we found that there was a pin position jump before the double vision, so we suspect that it was a problem with the former rule. However, after inspection, the front gauge and side gauge are also normal.
(1) Is the blanket aging? Since the operating side of the printed product does not have ghosting, the cause of the aging of the blanket can be eliminated.
(2) Is the roller blanket lining different in thickness? After updating the lining, the failure still exists, indicating that the problem is not there.
(3) Is the printing pressure balanced? After inspection, the printing pressure is the same.
Finally, it was found that the pressure roller close to the front gauge on the driving side was too loose. After adjustment, the ghosting fault was removed.
Author: Wang Jianming Zhejiang Ideal Group
One shadow failure troubleshooting