After the sheet-fed offset printing machine has been in operation for a period of time, due to the various degrees of wear of the machine parts, especially the opening cam, projections, tooth pads and tooth seats, the paper transfer cannot be carried out normally during printing, and it is often easy to bite The edge of the paper is bitten, resulting in inaccurate overprinting. The bite of the edge of the paper is not correct in the previous position, and the quality of the printed product is affected. 1. In the process of collecting paper, the offset printing machine should be comprehensively analyzed and treated differently. Check carefully that the teeth of the receiving paper and the roller are too close to each other. Make the paper in the process of handing over the printing paper. The edge of the bite is broken, the solution is to cross it properly. 2. Under normal circumstances, the size of the impression cylinder and paper delivery bite of the printing machine is about 12mm. The distance between the roller and the paper delivery bite cannot be too large, so that the bite distance of the delivery tooth is too large. If the continuity of the paper edge is bitten, and the position remains unchanged. If you find such a fault, you need to find the reason on the delivery tooth and the roller tooth. Turn off the offset press slowly and carefully check whether the process of handing over the paper and the roller tooth is accurate. The time for the tooth extension is too slow or the angle of the tooth extension Larger, and it is easy to cause the paper edge to bite and break. Check the wear of the paper tooth cam of the paper delivery tooth. If the cam wear is serious, repair welding or new parts may be required. When the delivery tooth is required to pass the paper to the impression cylinder big teeth, the delivery teeth and the drum big teeth control the paper at the same time. 3. The bite edge of the bite bite caused by improper adjustment of the bite row of the offset printing part is mainly broken, mainly due to the inconsistency of the height of the tooth pads of each bite, or the tooth pads are not straight, so that the individual teeth are not enough Zhang closed. Therefore, the bite of the papermaking paper is broken. The solution: readjust the pads of the paper-grip row to make it straight and uniform in height, and then carefully adjust the bite force. To adjust the bite force of each bite, a piece of 80g /? Kraft paper can be used to reach into the bite and pull it out by hand to test the bite force. 4. The position of the front gauge is not adjusted well, so that the roller bites the paper too much and the paper receiving tooth bites too much, so the paper bite edge is broken during the handover process. Solution: Properly adjust the bite distance of the front gauge to control the bite distance of 3-5mm. 5. The edge of the offset bite paper is bitten, the paper is broken irregularly, and the break is wide for a while and narrows for a while. This phenomenon is generally due to the inconsistency of the tightness of the tape on the feeder of the offset press. In addition, turn on the paper to see whether the pressure roller of the paper conveying line can rotate flexibly. Drive the offset press slowly to see if the time when the paper arrives at the front gauge is appropriate. In general, the requirement is that when the current gauge reaches the paper receiving position, there is a distance of 8-10mm from the front edge of the paper edge. Adjustment. 6. The main point of the bite paper edge being broken, the transfer position of the delivery bite and roller bite is not on the public normal line, or the transfer of the delivery bite and roller bite is parallel for too long. Solution: First, adjust their handover position, move the machine with both hands during the adjustment, and carefully check and correct it; Second, shorten the handover parallel time of the paper collection and roller teeth. 7. The edge of the paper is broken due to the paper. In the papermaking process, only interwoven fibers are used to form paper, which will cause uneven density. There are many trachoma and voids in the structure, and the paper surface is uneven. Therefore, a certain amount of fillers, glues, and colorants should be added to improve the paper surface. Smoothness, reduce paper transparency, reduce paper ink absorption, increase paper whiteness, weight, water resistance, toughness, etc. If the paper is too dry, the fiber has poor toughness, is brittle, the paper is loose, and the flatness is poor, it will also easily cause the paper edge to break during the paper feeding, short regulation, and embossing. In short, there are three forms of faults that bite the paper edge during the offset printing process: â‘ The paper bite is continuously broken, and the damaged position remains unchanged. The reason for this is that the delivery teeth and the roller teeth are not properly transferred or the delivery teeth and the roller teeth are not adjusted properly. In daily work, the offset printing should be adjusted properly from paper feeding, regulation, imprinting, and paper receiving. The paper edge at the bite is broken and related to each part. The worn open tooth cam requires welding and replacement. For accessories, do not move blindly after problems occur to avoid adjustment disorder and bring a series of process failures. Reasonable adjustments should be made according to the data required in the motor relationship table in the instruction manual of the offset printing machine. Paper delivery teeth, roller teeth, and paper receiving teeth The height of the three parts of the pad biting paper transmission must be adjusted uniformly. The opening and closing time and the size of the three parts of the delivery tooth, the roller tooth, and the receiving tooth pad must be consistent. The handover is accurate and in place. Several problems should be paid special attention to during the adjustment process when the fault is broken. Pump Water,Aquarium Water Pump,Submersible Water Pump,Electric Water Pump HENGYUE INDUSTRIAL CO.,LTD , https://www.hetoaquarium.com
â‘¡ Not every bit of the paper is bitten, but a few sheets that are not bitten apart, with regularity, mainly due to the arrangement of the teeth of the paper collection system. Pay attention to adjust the bite force of the delivery row.
â‘¢ The bite edge of the paper is large and small when it is broken, and it is good for a while, and bad for a while, and it does not have regularity. This phenomenon is generally due to the improper adjustment of the offset press feeder or the improper adjustment of the height of the front gauge. These two parts should be adjusted separately.