Enlightenment from troubleshooting the most popula

2022-07-31
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Enlightenment from the troubleshooting of one-time paper feeding

a Heidelberg SM 102v printer in our factory transferred offset paper after printing coated paper (long version live), and suddenly there were problems such as unstable paper suction, paper skew and double sheet. Adjust the paper separation suction nozzle, presser foot, paper pressing disc and paper delivery suction nozzle according to the normal position, and the fault still exists. At first, it was suspected that excessive air blowing caused friction between the paper delivery nozzle and the paper, resulting in double sheets and skew sheets. Therefore, the air blowing was reduced, and the side air blowing was reduced (or even turned off). The situation was improved, but skew sheets still occurred from time to time, and the speed could not be improved. After observation, it is found that the paper delivery suction nozzle sometimes straightens and does not retract, so the suction capacity is increased and the elasticity of the spring in the paper delivery suction nozzle is adjusted. The problem remains the same. After that, the paper delivery suction nozzle was cleaned, and the same phenomenon occurred after 1000 sheets of paper were operated normally. Considering that the paper delivery suction nozzle is a domestic accessory that was replaced after the original paper delivery suction nozzle was worn, it was removed and compared with the worn original paper delivery suction nozzle. It was found that the size of the air inlet on both sides is different. The diameter of the side air inlet of the original paper delivery suction nozzle is about 1.2mm, while the diameter of the side air inlet of the domestic accessory is about 0.6mm. Then the side air inlet was slightly larger, installed and debugged, and the fault was eliminated

when printing coated paper and offset paper, the adjustment methods of paper feeding are different, such as the size of air volume, the height of paper delivery nozzle, etc., which need to be adjusted by the operator using the potential practical experience in high-performance tires, damping materials, etc. The following is an analysis of the influence of the size of the air inlet at the side of the paper delivery suction nozzle on the paper feeding of coated paper and offset paper

first, the surface smoothness of coated paper and offset paper is different. The surface of coated paper is smooth, and the friction between the paper delivery suction nozzle and the paper surface is small. During printing, the paper can be blown up (blowing by the side air, increasing the air blowing of the presser foot and the front air), reducing the distance between the paper delivery suction nozzle and the paper, which is the base of the aluminum industry. For this industry development direction, the distance between the paper delivery suction nozzle and the paper can be checked. Even the paper delivery suction nozzle can keep in contact with the paper all the time, and there will be no skew or double sheet phenomenon, Therefore, the size of the air inlet on the side of the paper delivery suction nozzle has little effect on the coated paper. It is easy to cause traffic accidents. The surface of offset paper is rough. If the distance between the paper delivery suction nozzle and the paper is too small before suction, it will produce large friction and skew, and even affect the paper below to produce double sheets. Therefore, it is necessary to increase the distance between the paper delivery suction nozzle and the paper before suction, and it is required that the suction amount is large and uniform. At this time, the problem of the air inlet at the side of the paper delivery suction nozzle is highlighted. If it is too small, it is easy to cause the phenomenon of paper suction fatigue

secondly, the coated paper surface generally does not produce the phenomenon of powder and hair loss, so the side air inlet of the paper delivery suction nozzle is not easy to be blocked, and the air suction can be kept unblocked. Therefore, the size of the air inlet at the side of the paper delivery suction nozzle has little impact on the coated paper. Compared with coated paper, offset paper has more powder and wool dropping phenomena, so the side air inlet of the paper delivery suction nozzle is too small, which is easy to cause blockage, resulting in the reduction of air suction and the formation of skew sheets

source: Printing Technology

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