Problems with offset printing thin paper

With the needs of daily life, more and more thin paper printing, and sometimes encounter the printing of 40 grams and the following thin paper, printing and other large-format thin paper off the need to pay attention to the following issues.

One, knock paper. Thin paper is soft and breathable, which makes it difficult to move paper. First of all, knocking at the mouth into a fan-like shape, the lateral rule at the knock-shaped, the length of the mark can be about 20cm, the knocking force should be heavier, dragging a little at a small mark, a small interval to increase its stress. Due to the presence of the knock marks, the paper on the pile paper table should not be too large, so as to avoid unevenness of the paper pile and difficulty in feeding paper.

Second, the paper section. The paper stack mouth is about 1cm below the top of the front stop paper teeth, the loose paper mouthpiece is adjusted to about 10 sheets on the surface of the blowing paper pile, the air volume is adjusted to be smaller, the paper suction nozzle is about 8mm from the paper surface, and the suction nozzle The rubber band should be replaced by a thin, thin ring. Adjust the presser foot lever to increase the distance between the stack of paper and the suction nozzle of the paper to avoid sucking double sheets. The feed nozzle is about 8mm from the paper surface. Adjust the pressure of the paper press roller. The press roller should be in the middle and parallel to the feeding belt and keep the pressure consistent. Reduce lateral pressure to avoid thin paper arching.

Third, the embossing part, when printing thin paper, remove the normal paper from the platen roller and replace it with the thick paper of the printed thin paper. At the same time, the rubber roller pad is cushioned with the same thin paper. At this time, the printing plate and the ink roller The smaller the pressure, the appropriate reduction in the amount of ink transfer. The pressure between the printing plate and the eraser, the eraser, and the impression cylinder is slightly increased, which facilitates the transfer of the graphic.

Fourth, tighten teeth, receive paper. When the paper enters the imprint, it is necessary to tighten the teeth on the paper-feeding tooth row, roller, and the delivery chain to increase the bite force and prevent the thin paper from sticking on the blanket because of its thinness, softness, low density, and low paper tension. Appropriately reduce the amount of paper blowing, avoid floating paper, and ensure that paper is collected.

Reprinted from: Asia-Pacific Printing Network