Troubleshooting of Double-color Machine's Asynchronous Pressure Failure

Two-color machine clutch pressure does not synchronize often result in three consequences; First, the pressure is not caused by the previous one or two pieces of paper is not a single color printing or graphics conversion is not full pressure and make the first few printing ink layer too thick, resulting in the end of print Second, the pressure is not in time to make the rubber roller on the ink transfer to the surface of the impression roller, when the normal printing and transfer to the back of the printed sheet to cause waste, while giving the cleaning roller an additional burden; the third is the paper encounter lose In the event of a paper failure, accidents involving rolling off plates and blankets will often occur in the absence of pressure, which will increase economic losses for enterprises.
A “Northren” brand J2204 double-color machine of our factory had a serious failure of synchronization between the upper and the lower color group clutch pressure; when the paper enters the printing part, the color combination pressure is later one, when the pressure is issued after the pressure command , The next color group is one step away from pressure. With regard to the consequences of the non-synchronous clutch pressure, the first two of us had almost no scrap caused by multi-stencil printing. However, for the third consequence, we really suffered headaches because we used packaging printing and the paper was 250 g/m2. The above whiteboard paper, so sometimes encounter the quality of the paper, but often occur rolling plate bad, blanket failure, there was a workday to replace two plates, three blankets (with woolen cloth) records , to bring huge economic losses to the factory. This problem has plagued the factory technicians. The machine uses a more advanced photoelectric sensor to detect paper feeding, and the program controls the pressure from the station. The main electric box is equipped with a Japanese-made C60P programmable PC. Consult a professional that the PC will not have a program failure. We open the operating side cover, issued a clutch pressure command, see the upper and lower color group clutch piezoelectric magnet synchronous action, run the machine to the pressure command. After one revolution of the drum was found, the electromagnet copper block of the coloring group could push the pawl to come into contact with the pressure contact block, so that the color could be pressed together; while the color group under pressure was also the pawl's ability to contact the pressure block after one revolution. Phase off, to achieve pressure. After the above inspections, it was found that there were no faults in electrical and mechanical aspects. What is the reason that causes the up and down color group clutch pressure to be out of sync? Is it because the rubber roller clutch is too large? Since we did not have a tool to measure the clutch value, we opened the transmission surface cover with this question, and groped our experience to adjust the rubber roller clutch compression limit screw. We first tightened the coloring group's pressure limiting screw a few times. After tightening the lower color combination pressure limit screw for several times, and then turning on the clutch pressure operation, it was found that the upper and lower color groups were highly synchronous and almost synchronous, and after repeated comparison and adjustment, the machine was finally able to meet the requirements of the clutch pressure synchronization. In the experiment, no failure occurred again. We analyze the reason that the coloring group is under pressure and the combined pressure under the color is excessive. Therefore, only when the drum is operated for one week, the clutch over pressure can be eliminated and the normal clutch pressure can be achieved.
Through this example to tell everyone that when the machine clutch pressure is not normal, if you exclude electrical and mechanical failure, you can find reasons from the clutch pressure limit. "Printing Technology" Author: Gansu Zhangye Flying Mating Yu color printing plant