Offset press has a wide variety of brakes, according to its role can be divided into positioning, limit, protection of three categories, there are absolutely static, there are relatively static, under normal circumstances is a double appearance, but also by the brake Screws are used in combination with each other. It is very important to rely on the correct position of the brake and adjusting screw. This article will take the North J2205, PZ4880-01B four-color machine as an example to analyze its function, adjustment method, and various failures caused by it. 1. Feed the machine by brake The brake on the feed roller shaft of the paper feeding machine has two functions, which can not only control the magnitude of up and down movement of the take-up roller, but also control the length of the paper pressing time. When adjusting, attention should be paid to the coordination of the relationship between the two. 2. Pre-regulation brake The front gauge is based on the position of the brake (J2205). During the operation of the machine, the loosening of the tightening nut on the inside of the operating surface should be prevented. 3. Paper delivery mechanism by brake The paper-feeding mechanism has two brakes: Firstly, there is a symmetry brake on the left and right sides of the paper conveying tooth shaft, which is the reference for adjusting the opening and closing amplitude of the gripper tooth. The adjustment method is: insert a 0.2mm thick strip on both sides of the brake, and remove the strip after adjusting the teeth. The second is the reversing brake on the rowing arm, which has positioning and shock absorption. When adjusting and controlling its positioning screws, special care should be taken to adjust the length of the delivery tooth row on the dental table for a long time. If the retention time is short, the registration accuracy will be affected. The correct adjustment method is to twist the brake screw so that the swing arm of the swing arm is about 0.08 mm away from the swinging cam. At this time, strict attention should be paid to the position where the two sides are separated and entered the contact point (to ensure that the delivery tooth row stays on the dental table for 27°); both sides must be on the brake while escaping at the same time, otherwise swinging the paper teeth on the tooth base When the stacking paper is unstable, the pick-up range is also inconsistent, and it is prone to inaccurate longitudinal misprints. The above problem is mainly caused by the J2205 machine. This part of the PZ4880-01B four-color machine has only one brake on the inside of the operation surface. Its positioning effect has disappeared because the delivery mechanism uses an equidistant conjugate cam and the cam The design and machining accuracy has reached the requirements, so the brakes only play a protective role. 4. Water transfer roller, ink transfer roller shaft brake When water is transferred and ink is transmitted, the brakes should be in contact with the brake screws; when the water is connected and the ink is received, the two should have gaps under the action of the tension spring. Here, it is easy to accumulate ink, dust, and other dirt. Failure to clean it in time will affect the gap between activities and cause difficulty in receiving water and ink. Attention should be paid to it. Always clean and diligently add fuel. 5. Imprinting roller squeezing shaft bearing brake Its role and adjustment methods are similar to that of the brake on the delivery reed tooth shaft. It should be noted that after disassembling and repairing the reed tooth shaft, the revolving bearing screw should be screwed to open and close the tooth bearing on the reed tooth shaft and embossing. The distance between the roller shoulders is adjusted to 13 ± 0.05mm. All the clamps on the shaft must be loosened during calibration. After adjusting the brake position, adjust each tooth again. 6. Clutch press brake The clutch presses on the limit of the brake to prevent over-compression and excess pressure. Care must be taken when adjusting. When adjusting, firstly press the brake screw and the pressure release brake screw loosely; press and press together, when the largest surface of the pressure cam comes into contact with the roller, turn the pressure and press the brake screw to make the clearance with the brake. 0.08mm, then pressure; When the largest surface of the pressure cam and the roller contact, adjust the pressure and rely on the brake screw by the brake gap to 0.02mm is appropriate. Why is the pressure clearance large? This is because when the offset press is operated, the pressure is applied at a low speed, and the pressure is released at a high speed. The clutch shaft has a large inertia at high speed, so the pressure is generally depended on the pressure. The gap between the brake and the screw should be slightly larger. In the J2205 two-color machine, two groups of clutch pressures are not synchronized, that is, when the upper group is one beat at a time, and the next group is one beat at a time (relatively speaking), the first print is printed on the second color and the first color is not printed. . This fault is mostly caused by improper clearance between the two groups of clutch press brakes and brake screws, as long as careful adjustment, this fault will disappear. 7. Take-up teeth row brake The role of the take-up tooth row brake is the same as that of the feed brake shaft. During the operation of the offset press, it is necessary to constantly observe whether these brakes are in the correct position and whether the brake screws are loose, and try to eliminate the fault in the bud.
On the function of the brake and the adjustment method of the offset press