J2203 offset press ghosting

In 1994, our factory purchased a J2203 offset press from Taipei. In printing. Under the second color, the printing roller appeared a phenomenon of circumferential ghosting. The ghosting began at the mouth of the mouth and then moved to the tip position, which seriously affected the quality of the product.
In view of the above situation, we compared and analyzed the products printed a few times ago and found that there were similar situations in previous prints, but the extent of ghosting was not obvious. Using the "layered method", the direction of this fault is a circumferential, local (grate or drag) ghost.
Based on the above analysis, we checked the machine in the following steps:
First of all, a careful inspection of the plate cylinder sleeve was performed because the amount of rotation of the cylinder sleeve was directly related to the ghost phenomenon, but no problems were found after the inspection.
Second, the drum lining and printing pressure were measured and calculated. The results were also in line with the printing requirements.
Finally, when we inspected the plate cylinder, we noticed that the small uranium and the connecting plate in the two-color circumferential plate-changing mechanism had loosening phenomenon. Then we carefully observed the two hexagon socket bolts in the original gear sleeve that fixed the small shaft. It has been disengaged, the fastening effect on the small shaft has been lost, and thus the circumferential rotation of the plate cylinder has occurred, resulting in a circumferential ghost.
Solution: After removing the connecting shaft, connecting plate, transmission helical gear and helical gear seat cover, the small shaft is re-fixed and ghosting disappears.