Causes and treatment of inaccurate overprint cause

Causes and treatment of inaccurate overprint caused by paper pulling in place

paper pulling in place refers to that when the side gauge is working, the paper pressing ball cannot pull the paper edge to the fixed position of the rule plate. It is usually called paper pulling in place. According to the actual production experience, the common causes and treatment methods are analyzed as follows:

1. The paper stop tongue of the side gauge is too low. During the actual production operation, the height of the side gauge paper tongue is adjusted by three times the thickness of the printed paper. When the height of the paper tongue is lower than three times the thickness of the printed paper, the paper sheet may not be pulled in place. When adjusting, first adjust the lock nut on the upper part of the side gauge, turn the adjusting screw clockwise, and then insert the three sheets of paper to be printed under the paper stop tongue. Even if it can be inserted gently, the adjustment is good. When tightening the lock nut, the three sheets of paper still need to be padded under it. After adjustment, try again a few times to prevent the nut from loosening with the deepening of science and technology

2. The pressure of paper pressing ball pulled by side gauge. The pressure of the side gauge pulling the paper pressure ball, including the pressure of the low-speed machine, is controlled by the spring behind it. When changing the paper with different thickness, the spring with different thickness should be replaced. The thinner spring is used when printing thin paper, and the thicker spring is used when printing thick paper. At the same time, the adjustment of the elastic spring is also very important, which is related to the real pressure of the paper pressure ball. Most of the paper tension is not in place due to the insufficient spring force. The adjustment of the side gauge spring of the general high-speed machine should make the maximum pull of the printed paper 10 ~ 12mm. The low-speed machine also uses the same method to tighten the spring, and the pull should be 10 ~ 15mm

3. The sector plate at the bottom of the side gauge (low-speed machine brace) is too low. When the sector plate at the bottom of the side gauge is lower than the plane of the iron plate, the paper will sag after the paper pressing ball is pressed down, and the same fault will occur to the brace of the low-speed machine, because the fulcrum under the sector plate is the eccentric small shaft. During correction, the convex surface of the eccentric small shaft can be twisted to make the sector plate surface equal to the plane of the iron plate. The brace of the low-speed machine is supported by two concave iron, The concave iron can be removed and planed with a planer. The planed thickness is equal to the distance between the brace and the plane of the iron plate. It can be adjusted after installation

4. The paper pressing ball pulled by the side gauge cannot rotate. As the axis of the side gauge pulling paper pressure ball is installed under the water bucket, the water bucket liquid may be dripping during the actual production operation, and the rust and bite may be caused by the pollution of paper wool, printing powder spraying and other dust caused by paperboard conveying. At this time, first remove the paper pulling and pressing ball, clean it with kerosene, and then install it. If the small ball can rotate freely, it can be adjusted. However, oil cannot be added to the paper pulling and pressing ball, otherwise oil will be generated, which will affect the flexible rotation of the paper pulling and pressing ball

5. The paper feed is too far away from the side gauge. When the paper sent by the paper conveying system is more than 10mm away from the side gauge and the Japanese fixture, the paper sheet may not be pulled in place. This problem seems very simple, but it often occurs in the actual operation process, which also brings the core product independently developed by the enterprise - 3-axis linkage injection molding machine. The general causes are uneven paper loading, non vertical baffle board, skew of paper pile up and down, etc. Therefore, in the actual production operation process, the baffle board should be corrected vertically, the paper feeding rules on both sides of the paper pile should be close to the paper pile, and the optimal pull of the paper transmitted by the paper conveying system from the side gauge is 4 ~ 6mm

6. The paperboard pressing ball presses the paper edge: after the paper on the paperboard enters the front gauge, the paperboard pressing ball should leave the paper edge, but sometimes the cutting size of the paper is too large, resulting in the paperboard pressing ball pressing the paper edge. Bring certain resistance to the movement of the side gauge, resulting in the phenomenon that the paper sheet is not pulled in place. In the treatment method, just move the two pressure balls backward

7. The "kilo" of low-speed machine comes down too early. If the "Jack" of the low-speed machine comes down too early, resulting in the phenomenon that the side gauge is not pulled in place due to resistance before the paper pulling work is completed, in this case, the machine should be shut down to readjust the pressure of the "Jack" so that the "Jack" can be pressed down when the side gauge is to be lifted but not lifted. Sometimes, this technical problem should be adjusted in reverse. If the lifting time of the "Jack" is normal and the pressure is normal, the working time of the side gauge should be adjusted faster, Adjust the control cam of the working time of the side gauge faster to the forward direction of the machine

8. The adjustment of flat brush wheel of high-speed machine is too heavy. When the brush wheel rotates in the direction of the clock and the brush wheel 2 can not be adjusted properly, even if the brush wheel rotates in the direction of the clock and the brush wheel can not be adjusted properly, and then press the brush wheel on the side of the clock to increase the resistance of the brush wheel 2

(author/Liu Tiefu)