The reason and solution of the bite breaking of the offset bite

After the sheet-fed offset printing press has been running for a period of time, various parts of the machine have experienced various degrees of wear, especially the parts of the open cams, cams, pads, and holders, so that the transfer of paper during printing cannot be performed normally. It is often easy to bite the edge of the paper. After the edge of the paper has been bitten and damaged, the predetermined position is not allowed. Errors occur during the transfer of a series of sheets of paper from delivery, drumming, and delivery to the teeth, causing overprinting and inaccurate printing. The printed product is nicked and the quality of the printed product is affected. influences. In actual work, the failure of the bite-cutting of the paper edge is caused by many reasons. To eliminate this fault, we must find the cause from the following points to solve the problem.

1, under normal circumstances, the size of the offset press bite bite is about 12mm, can not make the roller bite and delivery paper teeth bite the distance too much, so that the receiving teeth bite too much, if the bite The continuity of the edges of the paper was bitten and the position of the bite remained constant. If you find this kind of failure, you must find the cause on the paper-feeding teeth and roller teeth, turn the offset printing press slowly, carefully check the process of transferring the paper between the paper-feeding teeth and the roller-big teeth, whether it is accurate, the teeth are too slow or the teeth are not open. The angle is large, causing a paper edge bite and broken. At the same time, the wear and tear of the feed teeth of the paper feed teeth must be checked. If the cam has serious wear, repair welding can be performed, or new parts can be replaced. When the paper is handed to the large teeth of the roller, the paper teeth and the drum teeth control the paper at the same time.

2, the offset printing machine in the process of receiving the bite of the edge of the paper edge is bitten broken failure to comprehensive analysis, different treatment, carefully check the delivery of teeth and flow tube teeth are too close to the position, in the printing process of paper transfer The edge of the paper bite broke. The solution is to cross it properly.

3. The bite of the mouth caused by improper adjustment of the teeth of the bite row in the delivery section of the offset press is bitten. It is mainly due to the inconsistency of the level of the teeth of the teeth, or the unevenness of the teeth, so that the individual teeth may not be open enough or may not open, thus causing the paper to crush and break. The solution is to re-adjust each tooth pad of the collection tooth, so that it is straight, high and low, and then carefully adjust its bite force on it. A small piece of 80g/m2 kraft paper can be used to adjust the teeth of each bite. Clenches into the teeth and the hand is pulled outward to test the bite force.

4, the former regulation of the position is not good, so that the roller bite bite paper too much distance, so that the receiving teeth bite too much, so in the transfer process makes the paper bite the edge of the broken. The solution is to properly adjust the distance between the front cheek paper and control the 3-5mm bite distance.

5, bite the edge of the paper is bitten, the paper is not regularly broken paper, and the break is wide for a while, narrow for a while, this phenomenon is generally due to the offset of the line belt on the offset roller device, in addition, the driving operation to see the paper feed line Whether the belt's pressure wheel can rotate flexibly. Slowly open the offset press to see if the time for the paper to reach the front gauge is appropriate. Under normal circumstances, the requirement is that when the current gauge reaches the receiving position, the distance between the front edge of the paper sidewalk is 8-10mm.

6. The main reason for biting the edge of the mouth is that the delivery position of the delivery teeth and the roller teeth is not on the public-normal line, or the delivery time of the delivery teeth and roller teeth is too long, and the first step is to adjust their handover. Position, adjust the machine with both hands to move the machine, carefully check and correct; second is to shorten the delivery parallel time of delivery teeth and roller teeth can be given properly.

In short, there are three types of failures that occur when the edge of the paper is bitten during the feeding process: 1 The paper bite is bitten and its position is not changed. This reason is that the delivery teeth and drum teeth are inaccurate. 2 Not every piece of paper is bitten, but instead it is divided into several pieces that are not bitten. There is also a certain degree of regularity. The problem is mainly due to the problem of the paper collection system's take-up tooth row. Pay attention to adjust the bite force adjustment of the take-up tooth row so that all bite forces on the row are uniform. 3 When paper breaks, the edge of the mouth is large and small, good for a while, bad for a while, and does not have regularity. This phenomenon is generally caused by improper adjustment of the offset of the offset printer, or adjustment of the height of the front gauge. It is not appropriate to adjust these two parts separately.

In the daily work, all systems, such as paper feeding, rules, stamping, and delivery, must be properly adjusted. The bite at the mouth of the mouth is closely related to each system. Worn open tooth cams require welding repair and replacement of new parts. There is something wrong with them. Don't disturb them. Avoid disturbances caused by a series of process failures, and at the same time, make reasonable use of the data required in the maneuverability chart of the instruction manual of the offset press. Adjustment, delivery paper teeth, drum teeth, paper escaping pad three parts in the bite paper transfer must be adjusted at the same height, delivery teeth, drum teeth, closing gingival teeth Zhang closed time, Zhang closed size must be the same, the transfer of accurate place They are several issues that should be taken care of when adjusting the bite-breaking edge.

Source: I love printing