A factory encountered such a situation in the production: J4104 offset press cam roller broke, fell between the printing plate and the rubber roller between the two transmission gear, in the two gear meshing process, the roller squeezed the printing plate The top of the gear 0.2mm, so that after the rubber drum gear side damage 0.3mm, and then fell into the transfer and delivery roller transmission gear, due to a timely shutdown, only two sides of the tooth damage 0.5mm. Due to the squeezing deformation of the tooth shape, one side of the tooth shape is pressed down and the other side is slightly convexly deformed. Despite the two restorations, there are still gravure and plate-off phenomena during printing. There are also bars on the printed products. Let us first analyze the reasons for producing bars and grinding plates.
1. Two bars appear after the first repair. The distance between the two bars from the mouth should be analyzed. Which one is due to the damage of the printing plate and the rubber roller transmission gear, and which one is due to the transfer and delivery roller transmission gears? Caused by the damage, whether the two bars are the same width, whether light or heavy.
2. After the second repair, the bars appearing are 5mm wide. The analysis of the position of the paper squeezing mouth is caused by the damage of the printing plate and the rubber roller driving gear, or the damage of the transmission gear of the stencil printing and the delivery roller. The second time the bar appears is wider or narrower than the first time.
3. Whether the position of the plate-off and grindstone is the same as the position of the second-time emergence bar, through analysis, it can be determined where the problem is after two times of repair. Based on the above analysis, it is possible to determine the treatment plan for the damage of the two drum transmission gears (print plate and blanket cylinder or imprint and delivery cylinder).
Since I was not at the scene of the accident and could not determine the exact place where the failure occurred, I had to propose two solutions here. If it is feasible, you may wish to try it when you encounter the same failure.
Solution one: Adjust the transfer (paper delivery) roller drive gear circumferential position
According to the information provided by the manufacturer, since the delivery roller drive gear of the machine is fixed with the sprocket, as long as the fixing screw is unscrewed, the gear can be rotated to any angle, and the damage tooth shape can be transferred out of the printing surface.
The specific method is to hoist or lift the delivery roller shaft, remove the parts on the outer wall of the wall plate, and then remove the sleeve (bearing) on ​​the wall plate at both ends to lower the delivery roller to disengage the two meshing gears. Unscrew the screws that fix the gears and rotate the gears to calculate how much the angle of rotation can be to remove the damage gear from the printed surface. Then align the screw holes on the gear with the fixing holes and tighten the screws. Finally, according to the order of disassembly, carefully install the parts on the drum to restore the running state of the drum (do not lose the parts), and turn the bearing circumferential position around 180°.
When re-printing, there may be two situations: 1) All the bars and the stencil disappear; 2 bars and the off-page phenomenon are reduced. If it is of the second type, then repair the damaged tooth profile on the impression cylinder, grind the other side of the tooth profile, and smooth the corners and burrs at the concave part of the damage. Because the helical gear drive enters or exits the meshing state with multiple teeth, one of the teeth has less local damage, which affects the printing. Special attention should be paid to the fact that this method is used when determining the cause of the bars and the plate-off causes in the damage of the transfer and take-up drum transmission gears. However, from the analysis, the failure of the factory is probably the reason.
Option 2: If the taps appear on the damaged parts of the printing plate and the rubber roller transmission gear, adjust the damage of the tooth of the printing plate gear to the printing surface.
The specific method is to hoist the plate cylinder and mark the circumferential position of each part on the roller axis with the marking pen (in the stationery shop). Fold off the parts and remove the bushings (The positions where the bushings at both ends are removed or installed must not be changed). Remove the screws fixing the roller gears and turn the gears so that the damage tooth shape is out of the printed surface. Then the roll printing state is resumed.
Problems with reprinting can be used to repair the damage of the rubber roller. Both of the above solutions do not require wall-breaking panels.
1. Two bars appear after the first repair. The distance between the two bars from the mouth should be analyzed. Which one is due to the damage of the printing plate and the rubber roller transmission gear, and which one is due to the transfer and delivery roller transmission gears? Caused by the damage, whether the two bars are the same width, whether light or heavy.
2. After the second repair, the bars appearing are 5mm wide. The analysis of the position of the paper squeezing mouth is caused by the damage of the printing plate and the rubber roller driving gear, or the damage of the transmission gear of the stencil printing and the delivery roller. The second time the bar appears is wider or narrower than the first time.
3. Whether the position of the plate-off and grindstone is the same as the position of the second-time emergence bar, through analysis, it can be determined where the problem is after two times of repair. Based on the above analysis, it is possible to determine the treatment plan for the damage of the two drum transmission gears (print plate and blanket cylinder or imprint and delivery cylinder).
Since I was not at the scene of the accident and could not determine the exact place where the failure occurred, I had to propose two solutions here. If it is feasible, you may wish to try it when you encounter the same failure.
Solution one: Adjust the transfer (paper delivery) roller drive gear circumferential position
According to the information provided by the manufacturer, since the delivery roller drive gear of the machine is fixed with the sprocket, as long as the fixing screw is unscrewed, the gear can be rotated to any angle, and the damage tooth shape can be transferred out of the printing surface.
The specific method is to hoist or lift the delivery roller shaft, remove the parts on the outer wall of the wall plate, and then remove the sleeve (bearing) on ​​the wall plate at both ends to lower the delivery roller to disengage the two meshing gears. Unscrew the screws that fix the gears and rotate the gears to calculate how much the angle of rotation can be to remove the damage gear from the printed surface. Then align the screw holes on the gear with the fixing holes and tighten the screws. Finally, according to the order of disassembly, carefully install the parts on the drum to restore the running state of the drum (do not lose the parts), and turn the bearing circumferential position around 180°.
When re-printing, there may be two situations: 1) All the bars and the stencil disappear; 2 bars and the off-page phenomenon are reduced. If it is of the second type, then repair the damaged tooth profile on the impression cylinder, grind the other side of the tooth profile, and smooth the corners and burrs at the concave part of the damage. Because the helical gear drive enters or exits the meshing state with multiple teeth, one of the teeth has less local damage, which affects the printing. Special attention should be paid to the fact that this method is used when determining the cause of the bars and the plate-off causes in the damage of the transfer and take-up drum transmission gears. However, from the analysis, the failure of the factory is probably the reason.
Option 2: If the taps appear on the damaged parts of the printing plate and the rubber roller transmission gear, adjust the damage of the tooth of the printing plate gear to the printing surface.
The specific method is to hoist the plate cylinder and mark the circumferential position of each part on the roller axis with the marking pen (in the stationery shop). Fold off the parts and remove the bushings (The positions where the bushings at both ends are removed or installed must not be changed). Remove the screws fixing the roller gears and turn the gears so that the damage tooth shape is out of the printed surface. Then the roll printing state is resumed.
Problems with reprinting can be used to repair the damage of the rubber roller. Both of the above solutions do not require wall-breaking panels.
Ningbo Wellcome Trading Co., Ltd. , https://www.huike-homecare.com