Analysis of the Causes of Emptying of Offset Printing Machine
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1. If the distance between the paper pile and the paper suction is improperly adjusted, a malfunction will occur, and if the distance is too large, an empty sheet will be generated. The distance between the paper separation nozzle and the paper stack, that is, the paper suction distance, should generally be between 2 and 7 cm. When printing thick paper, it can be smaller. When printing thin paper, prevent double sheets or prevent double sheets or The generation of multiple sheets can slightly adjust the distance. The former is about 2-4 cm and the latter is about 5-7 cm. The general treatment method is to loosen the screw that controls the height of the blowing presser foot and adjust the blowing pressure foot upwards appropriately. The reduced distance is the ideal distance between the paper stack and the paper separating nozzle.
2. The paper stopper brush is too low or too far into the distance. The function of the paper-blocking brush is to assist the paper blowing nozzle, so that the paper to be loosened maintains a certain height and no longer fits with the paper below, which facilitates the smooth feeding of the paper feeding system, and its function and the paper blowing The mouth is closely matched. When the air volume of the loose paper nozzle is normal, it can blow the paper edge and the height is about 5mm, which is the distance that the paper stopper brush should leave the paper pile; when the paper suction nozzle is used to suck the paper, Just touching the paper surface blown by the wind, if the paper stopper brush is pressed too low, the paper can not be opened and can not be looked down, it is equivalent to increase the distance of the paper separation nozzle to the paper surface, it is easier to cause empty Zhang. Sometimes the paper-blocking brush protrudes too much, and although the paper-splitting nozzle can suck the paper, it will be bounced off by the brush and cause an empty sheet. The solution is to re-adjust the brush, adjust it to about 5mm from the stack surface, and adjust the distance to 8mm.
3. The paper is slightly curled down. There are two reasons for this phenomenon, the first reason is that the airflow blown by the paper blowing nozzle is not easy to enter the paper gap, the airflow does not open the paper when it reaches the paper edge, and the other reason is that the paper suction nozzle is used to suck the paper. In the case of air leakage due to uneven paper surface, the paper may not be blown up and cause empty sheets. The usual processing method is to remove the paper and perform a positive knocking process.
4. Insufficient suction. Sometimes the ink on the nozzle and rubber band is accumulated for a long time without being cleaned, or the rubber band is worn and broken, and air leakage or suction is insufficient when sucking paper, which may cause empty sheets. The treatment method is to strengthen the inspection and maintenance work, especially when the front color is full version and the color is printed.
5. The airway is blocked. Most of this is due to blockages in the suction system (both from paper and dust), and most of them are blocked in the suction nozzle pipe and the control piston. When there is oil in the piston, when paper wool and dust are adsorbed to it, most of it is stuck by oil, and more and more accumulated. Finally, the suction air path is blocked, resulting in insufficient suction and emptying. In this case, it is necessary to regularly clean the gas path and the piston, and print rough paper such as cardboard, and insist on cleaning once a week. The oil in the piston should be replaced by a 1:1 mixture of train oil and engine oil.