The paper transfer device directly affects the accuracy of paper transfer and overprinting. Therefore, the adjustment of the paper transfer device is a very important and meticulous work. The following uses the eccentric swinging paper transfer device as an example to introduce the adjustment methods in several aspects . 1. Adjustment of the transfer position of the gripper of the delivery paper and the roller and the front rule The handover position refers to the relative position of the two handover parts when handing over the paper. One of the parts is used as the reference, and the position of the other part is adjusted to match the reference position. The adjustment of the handover position is in order. of. The paper delivery tooth transfers the paper twice with the front rule and the roller gripper. The position of the paper transfer between these two times should be based on the impression roller gripper. After adjusting the delivery position of the delivery tooth, the delivery can be determined. The position where the tooth picks up the paper at the front. Then, based on this position, adjust the working position of the relevant parts at the front gauge. The transfer position of the paper feed tooth and the front gauge: it is determined by the positioning screw 10, and the machine is slowly turned during adjustment to swing the paper feed tooth to the front gauge, and the positioning screw is against the stop 14 on the paper feed shaft. When the low point of the cam and the roller have a gap of 0.03 ~ 0.05mm, if the gap is too large or too small, the positioning screw can be turned to adjust. Of course, the time and force of the positioning screw and the stopper on both sides should be resisted Consistent. Then adjust the positioning plate of the front gauge so that the positioning plate and the paper-feeding tooth are on a parallel straight line, and the paper-feeding tooth gripper is in the range of 3 to 5 mm (see Figure 4-8). 2. Adjusting the height of the tooth pad The adjustment of the height of the transfer tooth pad is based on the height of the gripping tooth pad of the impression cylinder. Ideally, the gap between the transfer grip pad and the impression roller gripping pad at the "0" position is a printing paper thickness. . However, because the paper is soft, the edge of the paper is not flat, and various factors such as adjustment, motion error, and paper thickness change, this state is difficult to achieve, so in general, the distance between the two dental pads is two printing papers Thick, or a piece of printing paper plus 0.2mm is more suitable. The specific adjustment method is: first use a piece of steel sheet of corresponding thickness, lay it flat on the working surface of the roller tooth pad, loosen the fixing screw, so that the delivery tooth pad rests lightly on the steel sheet, and then tighten the fixing screw, so Adjust all the dental pads one by one on the straight line parallel to the plane of the roller (the overall adjustment is also possible). The paper feeder picks up the paper at the front gauge. When it is at the lowest position, the gap between the surface of the tooth pad and the iron table should be determined according to the thickness of the paper. When printing thin paper, the gap is three times the thickness of the printed paper; When printing thick paper, it is better to add 0.2mm to the thickness of the printing paper. During the adjustment, the height of the tooth pad is used as a reference, and the height of the paper iron table is changed by the fixing screws on the back support plate of the paper iron table, so that the gap between the tooth pad and the paper iron table meets the requirements, and then the fixing screws are locked again. That's it. [next] 3. Adjustment of the gripping force The gripping force is the pressure between the dental tablets and the pads. Whether it is transferring paper gripping or impression roller gripping, it needs to be adjusted during the printing process, because: (1) Long-term use leads to a reduction in the spring force of the spring, which reduces the gripping force. There are generally two methods for testing the gripping force. One is the overall test, which is to let the gripper hold the whole piece of paper, according to the feel, and the second is the individual test, which is to let the gripper hold the kraft paper strip, and judge based on the feel Sometimes when adjusting the roller gripper, you can stick some butter on the dental pad, stick the paper strip to each dental pad, and then close the gripper to test its gripping force. [Expert Tips] To adjust the gripping force of gripping teeth, it is necessary to prevent "dead teeth" (dental slices and dental seats are integrated). When adjusting the small support spring, the screw and the tooth plate bear, and the gripping force of the tooth plate cannot be increased. Therefore, the small support spring is compressed by the screw, so that there is no room for loosening between the tooth plate and the seat. When the total spring increases the pressure, The gripper will accept the full pressure of the total spring. [next] 4. Adjustment of the gripping force of the paper transfer roller In many imported offset presses, the gripping force of the transfer cylinder needs to be adjusted, as follows: ⑴. Turn on the paper safety switch. The handover time refers to the time that the handover mechanism controls the paper at the handover position (near), which means that the handover mechanism also controls the paper, and the paper pickup mechanism begins to control the paper. After a period of time, the handover machine When the piece releases the paper. There is no order requirement for the adjustment of the transfer time. As long as the transfer position is correct, the transfer time can be adjusted. The length of the transfer time depends on the approximate degree of the movement state (speed, track) of the transfer mechanism when the paper is transferred. Handover time of the delivery tooth and the impression cylinder gripper: The delivery tooth delivers the paper to the impression cylinder gripper. Here the delivery mechanism is the delivery tooth, and the delivery mechanism is the roller gripper. Their trajectories are circumscribed arcs, and the speed (cylinder linear speed) is equal during the transfer time, that is, they are in a relatively static state. The time of putting paper is only (instantaneous). [next] The specific adjustment is: the time when the roller gripper starts to grip the paper should be 1 ° before the "0" position. At this time, the roller gripper cam and the roller have just started to detach (for the low point), the roller can just be Rotate, but there is still some resistance, then turn the surface of the roller through 2 °, adjust the position of the transfer gripper opening and closing cam Figure 10-10, so that it just contacts the transfer gripper roller but it can still rotate, slightly There is resistance, this is the time when the transfer paper gripper starts to put paper (359 °), which ensures that the transfer tooth row and the roller gripper simultaneously control the paper to rotate at a constant speed of 2 ° (equivalent to φ300mm roller turn 5mm Arc length), the transfer time should not be too long, otherwise it will tear the paper, but it should not be too short to avoid inaccurate overprinting. Handover time of the delivery tooth and front rule: the delivery of the delivery tooth and the front rule is carried out in a stationary state (V = 0, track is a point), when the delivery tooth has just entered the delivery position and is in a stable delivery state , The cam and the delivery gripper roller are just detached, so that the delivery gripper closes the gripper, that is, the start time of the delivery time (77 °), and then the roller is rotated through 3 ° (equivalent to φ300mm roller through the arc 8mm long), the front gauge just swings to make the paper (74 °), which is achieved by borrowing the front gauge to drive the cam position. [Related Links] The fact that the delivery tooth actually picks up and locates the paper on the paper conveying table refers to the handover of the delivery tooth and the side gauge. This is because the front gauge is the first position before the paper arrives, and the side gauge is the second position. Therefore, it is the most important to adjust the handover time between the delivery tooth and the side gauge. [Case 4-1] A factory has a J2205 machine, which often has overprint failures. At first, it was suspected that there was a problem with the side gauge. After inspection, there was no abnormality in the side gauge. Later, after repeated inspections, it was finally found that the delivery tooth held the paper in advance. Obviously, there is a problem with the handover time between the side gauge and the delivery tooth, and you must readjust it at this time. In order to ensure that the paper gripper just grips the paper while the pull gauge is lifted, so that the paper is accurately positioned and transported, first adjust the side gauge pressure cardboard lifting time, click the car to 77 °, and tear the printed sample into paper Strip, placed under the paper pulling wheel, adjust the cam that controls the swinging motion of the paper pulling wheel, so that the paper pulling wheel has no pressure on the paper, and then loosen the fastening screw of the paper delivery closed tooth projection, rotate the position of the projection, at the same time Use paper strips to test the gripping conditions of the paper delivery teeth, so that the paper delivery teeth have just gripped the paper, and finally tighten the fastening screws of the protrusions, the fault disappears and the overprint is accurate. [Expert Tips]: (1) Whether the hand-over relationship between the side gauge and the delivery tooth is coordinated and accurate is the key to ensuring overprinting, and the two can't interfere with each other. [Case 4-2] The up and down rules of the drive side (outer side) of a factory J2205 machine are always not as good as the up and down rules of the operation side (back side). At first, the captain thought that this was related to the side rule. After careful observation, it is found that when the paper delivery tooth and the roller gripper are handing over the paper, the paper delivery tooth bar on the transmission side and the operation side feels different, so the captain removes the paper delivery tooth opening plate. It was found that the splint was badly worn and could not be used. Later, a new splint was replaced. [Expert Tips]: (1) Generally speaking, the rules are good at the same time and bad at the same time, which is often related to the position of the side gauge, but this is not absolute. (2) After excluding the side gauge factors, it is necessary to consider the paper gripping force, generally very Few people think about handing paper bars. Regarding the constant force device, the large tension spring 8 (Figure 4-13) has one at each end of the swing shaft of the paper delivery tooth, which ensures that the roller of the paper delivery device and the cam are tightly contacted to prevent the paper delivery due to any vibration The instability of the tooth transfer paper to avoid the position change when the paper transfer. Therefore, the tension of these two tension springs is great. When the delivery tooth swings in the direction of the roller and the large tension spring 8 is stretched to the maximum length, its pulling force will be more than double the length of the concave surface of the cam. Due to the large variation in the pulling force gap, the cam wear is also very serious, so , It also has a great impact on the stability of the machine. In order to overcome the above drawbacks, the tension springs of the paper transfer device are equipped with spring constant force devices. When the oscillating fan-shaped plate l is downward, the high point of the cam 3 is downward, so that the cross-fulcrum of the oscillating lever 4 is lowered, and the length of the tension spring will not be shortened by the fan-shaped plate. Moving up, the length of the tension spring is still the same, so no matter whether the transfer tooth swings to the upper limit or the lower limit, the tension of the tension spring is basically the same, and the variable load is reduced to make the machine transmission stable. When making adjustments, it is necessary to check in detail and control the uneven surface of the adjustment cam to the minimum range of extension and shortening of the tension spring. [Related Links] Mechanisms like this make use of the characteristics of a common-wheel cam. This device is ubiquitous in all types of offset presses.
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Figure 4-9 Handover of the delivery tooth and roller gripper
(2) After long-term use, the dental pads wear out, resulting in reduced gripping force or inconsistent gripping force of grippers.
(3) Paper powder is often adhered to the gripper during printing, and foreign objects such as ink are likely to cause the gripper's gripping force to decrease and cause various failures.
(4) The opening and closing time of each gripper is inconsistent, which is easy to cause the pad to wear and affect the gripper force. The adjustment of the gripping force of the delivery tooth must be carried out on the basis of accurate adjustment of the height of the delivery tooth pad. Otherwise, the gripping force will be affected due to the change in the height of the dental pad. The specific steps and methods for adjusting the gripping force of the paper transfer gripper:
a. Turn the machine to the position where the delivery teeth grip the paper on the edge of the paper feed table, and the cams and rollers that control the gripping teeth are disengaged from contact. Immediately pass the paper gripper to enter the closed tooth area.
b. Insert a 0.25-0.3mm thick piece of paper between the positioning stopper of the gripper shaft and the positioning screw (backer).
c Loosen the fastening screws of all grippers so that all grippers are not closed.
d Test the gripping force and adjust the gripping force in the order shown in Figure 4-10, then tighten the tightening screw 3 and place a 0.1 mm thick kraft paper strip between the dental pad and the dental pad to test the gripping force.
e. Remove the piece of paper between the positioning stop and the positioning screw (backer). At this time, the gripping tension spring makes the positioning stop and the positioning screw close. All the small springs of the gripper increase the same amount of compression. That is to increase the equal grip.
f Adjustable screw during fine adjustment 7
Figure 4-10 J2108 machine paper delivery tooth structure and adjustment sequence
[Related Links]
The distance between the tooth plate of the delivery roller and the dental pad (Figure 4-11 / â‘ ) needs to be adjusted according to different printing materials.
Figure 4-11 Transfer roller gripping force adjustment
⑵. Jog the machine forward until it can be adjusted to the locking screw (Fig.4-11 / ②).
(3) Open the shield in front of the transfer roller.
â‘·Remove all the locking screws (Fig.4-11 / â‘¡).
⑸ Continue to jog the machine until the scale is exposed (Figure 4-11 / ③).
⑹Use a socket wrench to rotate the scale (Figure 4-11 / ③) to the mark line (Figure 4-11 / ④). Each grid on the scale represents 0.1mm paper thickness.
? Hint: In order to prevent the pattern gap on the scale, it is best to rotate the scale clockwise to set it.
â‘´. After the correction is completed, continue to jog the machine until it returns to the position of adjusting the locking screw.
⑵. Tighten the locking screw (Fig.4-11 / ②).
4. The adjustment of the transfer time between the gripper of the delivery paper and the impression cylinder and the front rule
Figure 4-12 Paper control cam
(2) Adjust the closing time of the delivery tooth based on the paper delivery tooth actually holding the paper.
(3) The lifting time of the side gauge varies with the thickness of the paper, that is, it cannot be determined that the paper pulling wheel and the roller under the paper pulling wheel have just come off.
(3) Whether the paper delivery tooth bar smoothly transfers the paper can be judged by the feel in practice. [next]
Figure 4-13 Spring constant force device 
