Analysis and Processing of Folds in Kobo Printing Presses Xinhua Printing Factory, Chaoyang, Liaoning
The KBA Rapida 104 four-color machine used to print a coated paper with a basis weight of 105 g/m2, causing serious wrinkles in the tail.
From the point of view of the failure phenomenon, it was initially determined that the wrinkles were generated after the first color combination pressure. After analysis, it was found that before the paper entered the first color group, the buckling force was uneven and could not hold the paper, causing the paper to slide within the tusks, resulting in unevenness of the paper surface, resulting in the first color combination. Wrinkles occur when pressed. Further analysis, which part of the space problem. First of all, with the transfer paper as the benchmark, the delivery device of the KBA Rapida 104 four-color machine is an intermittent double-row tooth roller, followed by a single-row tooth transfer roller, and then the paper enters the printing unit. Jog the machine, enter a few sheets of paper into the tusks, hand-pull the end of the paper, and find that there are a few tusks in the transfer cylinder and cannot hold the paper. Increase the enthusiasm of these fangs and adjust them with uniform and consistent standards. Reboot, troubleshooting
Lining Material Elastic Restoration Method Hubei Yuxian Printing Factory Wang Xincheng
The blanket lining materials such as felting and worsted wool inside the blanket cylinder of the offset printing press can lose their elasticity due to long-term rolling pressure. The following treatment methods can be used to restore the original elasticity.
Dipping the old felt wool and fine wool immersed in the detergent solution with water temperature of 60°C for 15 minutes. After the water is cool, wipe each felt and worsted wool material by hand. If both sides are stained with ink and other dirt, try to Scrub, then rinse with tap water until clean, gently wring the water, then rinse the clean felt, worsted wool, dried in the sun, or dry on a barrel or circular wood. Resilience.
When drying, pay attention to not be allowed to be folded on the fine iron wire, so that it is easy for the felt and the worsted wool to have obvious wrinkles, which is not conducive to the loading of the rubber roller. At the same time, the finished products of felt and fine woven wool should be rolled into cylindrical shape in warehouses and workshops to prevent wrinkles from folding.
The Inspiration of Abnormal Sound ç¿Ÿ Xi Lin
When a PZ4650 four-color melter was used to print a light weight paper with a basis weight of 65 g/m2, lateral ghosting and wrinkling occurred on the paper in the second color group.
Check the buckling force of the cavities and the condition of the attack pad well, and there are no signs of loosening of the fixing screws of each roller. When the maintenance personnel adjusted the pressure of the impression cylinder tooth, the situation improved, but the malfunction recovered after a period of time.
Checking the open bearing again stopped the machine and found no problem. However, when the machine was jogged, accidentally, it was clear that the fangs were stuck and suddenly released and closed again. Based on this finding, the maintenance personnel carefully examined again and found that the connecting rods of the impression roller of the second color group were all displaced toward the operation surface, and the open bearings were pressed against the wall plate. The reason for the displacement was analyzed. It was originally that the washer and the retainer at the fixed link end of the transmission surface came off. Pull the connecting rod to the drive surface to the proper position, then install the washer and retainer, and turn it on again. The printing effect is good, and no ghosting or wrinkling occurs.
Reconstruction of JS2102 Offset Rolling Bars of the Offset Press of the CPC Central Party School Li Yongliang
The JS2102 offset press has a higher failure rate of the drum teeth, and the maintenance adjustment is very troublesome. The main failure phenomenon: tooth decay has not yet worn, tusks and teeth began to uneven. When adjusting the fine-tuning top wire, it is difficult to adjust to the proper position because it is not to stand up to the tooth rack or to lift the top sheet. Cause of failure: The clamp on the shaft is pushed out of a hole by the top wire and it is exactly halfway to the seam. Normally this happens, the factory will replace the new clamp or fill the pit with a welding method. However, in fact, these solutions not only increase maintenance costs, but also do not solve practical problems.
According to many experiments, the author found a very effective method. When repairing the row of teeth, first remove all the clamps and find some φ5.5mm steel balls. Use a drill with a diameter of 5mm to drill a round hole at the top of the clamp ring. Put a steel ball in the pit. The steel ball should be half above the plane. When installing the steel ball, it is better to wipe the butter, so that the ball is not easy to fall out when the bracket clamp is installed, and it can also play the role of lubrication.
After the refitting drum row, even if the spring is broken, the steel ball will not fall out, so it is safe and reliable. Its greatest advantage lies in extending the service life of the drum teeth.
Maintenance of monochrome printing machine Hefei Xingguang Printing Factory
The factory has a monochrome printing machine, after adjusting for everything in the off-season, it has not been printed for a long time. Afterwards, most of the two-color printing of the printers are plain web prints. Since no car washes before printing, the ink is printed on the middle part of the prints. The ink of a size of about 2 cm 2 becomes shallower and lighter, and the printing speed is reduced. It is back to normal. A forward inspection from the blanket cylinder showed that although the ink on the transfer roller was uniform, there was a non-inking on the chain roller and the axial position was the same as the printed product. Touching it with his hand, it feels smoother. The oil drops on it. Because the car wash operation was too cumbersome, the operator used a cleaning paste to clean the place where the roller was not inked, and then wiped it with a dry cloth to find that the effect was the same as that of the car.
Experience: When the printer does not work for a long time, it should be covered with cardboard or plastic film to prevent dust from falling onto the roller and causing it not to ink. Also, be careful not to drop oil on the rollers during maintenance.
Clever use of cleaning paste in addition to dirty Liaoning Jincheng Printing Factory
Graphical parts except dirty
During the printing process, when the printed sheet was drawn, it was found that the graphic part of the printed product was floating (stencil), and after stopping, the cleaning paste was taken with a wet rag, the stain on the printing plate was wiped off, and the wipe was wiped again with clean water. , and then start printing. In doing so, not only the work efficiency is low, but also the reboot of the machine will make the inks of the first few dozens of inks darker and more wasteful. In my daily work, the author summarized a method that can eliminate the floating of the printing plate without stopping the machine and ensure the continuity of the printing. The specific method: when the printing press is in normal printing, use a damp rag to clean the paste, and wipe the corresponding fountain roller according to the position of the plate from the dirty position. The cleaning paste on the fountain roller is transmitted through the chrome roller and the dampening roller. On the plate, the bleed on the plate immediately disappears. In doing so, the effect is very good, and it saves time, effort, and improves work efficiency.
Non-graphical parts except dirty
If there is ink in the circumferential direction of both sides of the plate or the non-graphic part of the plate, it should be removed in time. On the other hand, with the progress of printing, the ink may be enlarged. Once it is diffused into the graphic, it will cause waste. Second, the ink will be transferred to the impression cylinder via the blanket cylinder. The cleaning cylinder will be very clean. Hard work. In the past, the ink on the ink fountain roller corresponding to the non-graphic portion of the printing plate was "broken up" or the pad on the non-graphic portion of the blanket cylinder was cut off. The above method is effective in removing dirt, but the amount of cleaning paste should be increased. When shutting down, it is necessary to check whether the pressure of the ink roller and the dampening roller on the printing plate is correctly adjusted.
Solving the problem of ink stick in offset printing Jinan Tianyi Printing Co., Ltd. Gu Jianmin
In the offset printing process, ink stick problems occur from time to time, directly affecting the quality of the printed matter. There are many factors that cause ink bars, but they are mainly caused by improper mechanical adjustment and damage to mechanical parts.
1. Improper mechanical adjustment caused by ink bars
(1) The pressure between the ink roller and the printing plate is too large, which exceeds the pressure between the printing plate and the printing plate, causing sliding on the printing plate. In particular, the two ink rollers that play the role of ink collection can easily cause ink sticks. .
(2) The pressure between the ink roller and the ink roller is too large, which exceeds the pressure between the plate and the plate, causing slippage on the plate. In particular, the two ink rollers that play the role of ink collection can easily cause ink. Bar.
(3) The aging or shape of the ink roller surface is changed, the left and right pressures are not adjusted, and the ink roller is caused to run when the machine is running, resulting in ink bars.
(4) The pressure between the plate cylinder and blanket cylinder is too large, mainly due to improper use of the plate cylinder or blanket cylinder liner, causing excessive pressure, making the circumference of the cylinder inconsistent, resulting in speed difference, causing ink bars.
(5) Improper adjustment of the pressure of the contact type bearer affects the center distance and the printing pressure of the roller, which causes the ink stick.
For the above problems, the following solutions can be used.
(1) Replacing the ink roller
(2) When adjusting the pressure between the ink roller, the plate cylinder, and the ink roller, it is strictly adjusted according to the data in the machine specification.
(3) Correctly calculate the lining amount of the roller to ensure that the line speed of the roller surface is consistent under a small printing pressure and the graphic and text transfer effect is good.
2. Damage caused by mechanical components
(1) The roller gear wear, the line speed between the rollers can not be consistent, resulting in ink bars.
(2) The roller bearing wears out after a long time, resulting in an ink bar.
Solution: Replace worn parts.
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