What parts of the offset press are easy to break
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First, the master of the paper feeder:
Properly grasping the feeder, enabling the paper to be smoothly transferred to the front gauge, reducing the failure during the paper transfer process, which is of great significance for ensuring the quality and production efficiency of the printed product. If the functions of the various components of the paper feeder are used properly, there will be no such problems as paper feeding difficulties, and vice versa, which can cause various paper feeding failures, resulting in a deterioration in the quality of the printed matter and affecting the yield. Paper skewing will cause difficulty in positioning the front gauge and side gauges, causing frequent downtime, and increasing the labor intensity of the operator, the drop in output and the imbalance of ink and ink. Therefore, a good printing press must have paper feeding. The work is stable and the paper is accurate. Of course, you must also be familiar with and properly adjust the functions of the various parts of the paper feeder.
The paper feeding system of PZX650 series four-open offset printing machine produced by our company can accurately deliver the paper to the paper positioning mechanism. The maximum paper feeding speed can reach 12000 sheets/hour, and it also has the function of non-stop continuous paper feeding.
The paper feeding head and the paper feeding belt are driven by a chain to keep pace with the speed of the main machine. For this reason, attention should be paid to adjusting the tension of the chain. Since the two chains need to be tensioned at the same time, you must not ignore this when adjusting.
(1) Introduction of the function of the specific mechanism of the paper feed head
The paper feed head is the core component of the entire paper feeder. Its function is to separate the paper on the paper stack and then feed it into the paperboard. This is a sophisticated mechanism whose functions are described as follows:
1), universal joint
The transmission part of the paper feed head drives the paper feed head to operate. The torque can be flexibly transmitted according to different specifications of the paper. In order to ensure that the running phase of the paper feeding head is synchronized with the main machine, attention should be paid to the orientation of the coupling during assembly or maintenance. The correct location is as follows:
The connection time between the Feida head and the feed roller is adjusted by the coupling and the joint flange.
2) Positioning locking device
After the paper feed head is adjusted to the correct position, it should be able to securely lock the entire part and ensure that the paper feed nozzle rod of the entire machine is parallel to the paper stack.
3), the paper feed head height adjustment mechanism
This is achieved by adjusting the star handwheel.
4), rotating mismatch valve and air volume control switch
Control the on/off of the airflow provided by the air pump (in conjunction with the paper feeding action to open or close the air supply in time). Check the coordination with the mechanical action. Generally, check the maximum distance of the paper feed nozzle when the paper feed is cut, and cut off the vacuum airflow (ie Paper release), the switch can adjust the air volume.
5), paper stick
Used to gently press the two back corners of the paper on the stack and prevent the paper stop from over-heading the paper.
6), paper blowing
It can be adjusted up and down, used to blow air into the trailing edge of the paper stack to make the paper loose, and it is easy to separate the paper by the paper separation nozzle. When working, the blowing pressure foot is pressed against the paper. Adjust the air volume according to the texture of the paper so that the upper 3-10 sheets of paper can be loosened.
7), paper nozzle (lift)
When the mechanism is moved downward by the cam to the lowest position, the nozzle quickly lifts a piece of paper on the surface of the stack, and when the paper feed nozzle moves to the position closest to it, the separation nozzle lifts again and releases the paper. Finish the transfer with the paper feed nozzle. The suction force can be adjusted, and the distance from the paper pile can also be adjusted by the handle. The paper suction surface is inclined. According to different situations, the direction and angle of the slope can be adjusted. When using, the suction force should not be too large, and the position should not be excessive. Low, otherwise it is prone to double-feeding paper failure.
8), paper sheet (or paper brush)
When the uppermost piece of paper is lifted by the separation nozzle, the steel sheet presses the remaining paper, and only the uppermost piece of paper is separated from the paper pile without being confusing.
9), blowing pressure foot
It is used to insert between the paper that has just been separated and the stack of paper below, press the paper on the paper pile, and blow air under the separated paper to form an air cushion, so that the paper feeding nozzle can smoothly feed the paper into the paper feed wheel and press Between the rounds. The mechanism has two distinct stages (when pressing)
A, insert
B, press down the paper
It must be proofread repeatedly when positioning. Under normal circumstances, when the connecting rod is at the lowest position under the presser foot, the upward tilt angle is about 8°, which will form a shovel when the presser presses the paper. Excessive assembly caused the presser foot to lack the pressing action, and kicking the paper forward caused the paper to be disordered.
In order to ensure the normal operation of the paper-feeding head of the paper-feeding head, it is necessary to keep the distance between the paper pile and the paper-cutting head from changing too much. The blowing-pressing foot mechanism also has the function of automatically raising paper to make the paper on the paper pile, as needed. Automatically and quantitatively rises, when the minimum position of the presser foot is corrected for this, the micro switch is just lifted up, and a click is heard, which is flexibly controlled according to the thickness of the paper, and generally rises once every 10-15 sheets (thin Paper 80-1008/m2).
10), paper feed nozzle
The paper lifted by the separation nozzle is sucked in time and fed into the paper feed roller. When the paper is conveyed forward, the paper stopper at the leading edge of the paper stack should be simultaneously lowered (retained), when the paper passes over the paper stopper. When entering the paper feed roller, the paper stopper quickly tightens the paper in the lower part of the gear.
It is required that when the paper feed nozzle feeds the paper forward, the gap between the paper feed roller and the paper feed roller when the paper is to be fed is 2m/m (instruction) (it is customary to feed the paper when the paper feed roller presses the paper) The mouth is slightly loosened first.) (The miller machine feeds the nozzle quickly and is suitable for higher speed and accurate paper feeding mechanism).
The paper feed nozzle is a pneumatic, time-flow component. When the nozzle fails to reach the paper surface, the nozzle extends back. After sucking the paper, it can be quickly raised. When using it, pay attention to the distance between the tip and the paper stack. Don't be too small. Generally, it is about 5-8 m/m. When using it, you should hear a crisp “beep” sound. When the paper is not protruding inside the tip, consider whether the vacuum is insufficient or whether the air path inside the tip is blocked by the paper. A paper feed nozzle on the starting side, its pitch angle can be changed to change the skew during the paper feeding process, so that the paper reaches the front gauge in parallel during the whole transfer process, because it is adjusted unilaterally, by speed or In order to achieve a certain degree of adjustment, you should pay attention to the adjustment mechanism in the middle of the adjustable part. The adjustment of the speed of the paper on one side can be adjusted during the paper feeding process.
The whole paper conveying head component can be determined according to the paper size and actual needs, and the position of the upper and lower movements can be determined before and after the blowing pressure. The trailing edge of the paper pile is 8-10 m/m, and the upper and lower paper piles are automatically raised to the upper and lower sides. It is better than 5 m/m below the paper stopper.
When the whole set of paper feeding heads is engaged with the paper feed roller, when the paper feed roller just touches the paper feed roller, the paper feed nozzle should be placed one step at a time (or as described above, the paper feed nozzle puts paper and feeds the paper). The pressure roller is 2 mm away from the paper feed roller)
11), the front edge of the paper pile
The air blown at the leading edge of the stack of paper blows the paper on the upper edge of the leading edge of the stack so that the leading edge of the paper can be fed smoothly between the paper feed roller and the feed roller.
(2) Stacking paper board
The stacking and lowering of the stacking table is carried out by two sets of mechanisms of the same principle, which are respectively driven by two electric motors to control the lifting of the main and stacking paperboards respectively, so as to realize the function of adding paper without stopping.
The stacking paper table is a mechanism for stacking paper materials to be printed. The PZX650 four-open offset printing press Feida has been used alternately to realize the function of non-stop and continuous paper feeding. The specific use method is not introduced here. I only pay attention to the installation and commissioning personnel. In addition to smooth lifting and lowering, the mechanism should also adjust his level so that the paper is stacked on the platen in addition to the flat plate. Before and after the parallel problem, the master we installed and debugged, sometimes tend to ignore this. Although if the stacker is not level, the operator can use wooden wedges or partial height to solve the problem, but this invisibly increases the workload of the workers, sometimes causing the failure of the paper delivery, I suggest that everyone pay attention to this problem. I have found in the user service that the difference between the left and right is 15 mm, and the difference between the front and the back is 8 mm, which causes a failure in the one-sided paper delivery.
There is also a installation and debugging problem related to the stacking table that controls the automatic reduction of the delivery switch of the delivery table. The adjustment and fastening of the two travel switches should be taken seriously to make the work reliable, otherwise it will cause significant Equipment accidents, damage to the paper tray. The problem is that the mounting seat of the travel switch is too wide, so that the roller of the switch is not caused by the middle of the chain roller, because it is not in the middle, and sometimes the switch of the roller chain piece causes the switch to shift and fails.
There are side gauges on the two sides of the front side of the stacking table. The function is the basis of stacking paper (backing), and the paper stack should not be clamped too much when used. There is a pre-lift paper limit switch in the middle. Its function is the changeover switch when the paper stack is raised, that is, the highest limit switch when the front plate is behind the front baffle bar. Above the stack of paper, there is a pile of paper high, the safety switch. When the presser foot is not stepped on the paper stack, it is prevented from accidentally raising the paper table and damaging the machine.