What happens when there is a problem with the cylinder sleeve of the printing machine?

Second-hand printing machine purchase - cylinder test endfragment test method is as follows, 1Thoroughly clean the foreign objects on the three rollers, 2Adjust the normal state of the ink and water channel.

3.It is best to remove the plate film and replace it with a medium-thickness backing paper (optional). 4. Replace the new adhesive tape with a new bottom paper, the bottom paper is less, adjust the pressure to 250 grams of pressure, test print with 157 grams of paper, and increase the pressure each time until the printing sample is normal in most places, and it can be divided into the following situations according to the inking situation, 1:

The uniformity of the printed sheet indicates that the cannon is very good. 2:) If it is found that the ink color is normal in most places of the sheet, and the position on the corresponding cylinder has traces of repair, it means that the local deformation caused by the improper repair gun, if the corresponding position can not see the damage, it means that the position has been crushed by the paper, and the position that is generally crushed by the paper is not easy to see the damage.

3:) If there is irregular weakness on both sides and at the end of the plate, it means that the plate is corroded. 4:

If the sides and the end of the plate are very regular like a frame, it means that the impression cylinder is corroded. 5:) If there is a 200mm weak white belt from left to right in the middle, then this belt is called a departure belt, which is caused by the wear of the bearings or bushings at both ends of the rubber roller, 6:

If the large area is light and the small area is heavy, and each one is the same, it means that the tape gun is deformed, if the two are different, it means that the rear gun is deformed. There are many items to be examined, which will be further described in the next article due to space limitations.

The black thread of the day, the black thread will become thicker and thicker if you use it regularly.

a) Longitudinal ghosting.

1. The matching gap between the cylinder journal and the shaft sleeve, the eccentric sleeve and the wall plate hole is too large, especially the matching gap of the printing plate cylinder is large, so that the drum vibrates during operation, the rotation angle speed of the cylinder is uneven, the printing plate cylinder and the rubber blanket roller can not be in contact with the same position every time, and the ink on the printing plate is transferred to different positions of the blanket roller for two consecutive times, and ghosting appears. Most of this type of ghosting occurs in the mouth of the printed matter. It is generally believed that the matching clearance of the cylinder sleeve is the best, and it needs to be repaired when it exceeds to ensure the printing accuracy of the printing machine.

2. The backlash and radial runout of the drum gear are too large, the service life of the offset printing machine is too long, the gear is worn, the tooth thickness is reduced, and the sidelash of the meshing teeth is increased, resulting in the failure of each cylinder to run at a uniform speed, resulting in instantaneous relative displacement between the cylinders and ghosting. Conditional factories can replace gears or bearings with serious wear; Appropriate key nuclei reduce the center distance of the drum to keep the side clearance within a certain range; Use liner paper to pad the mouth of the blanket into a trapezoidal shape to reduce the vibration caused by the impact of the mouth, and to varying degrees overcome the ghosting caused by the excessive backlash of the drum gear and the excessive radial runout.

3. Improper lining of the drum, excessive pressure, and inconsistent surface linear velocity, resulting in excessive extrusion force between the drums and changing the extrusion value of the blanket. Due to the large amount of extrusion deformation and displacement of the blanket, it cannot be completely restored to the state before compression, resulting in ghosting when the ink is transferred.

In the rolling process of the three cylinders of the offset printing machine, it must be reasonable rolling, so that the three cylinders can obtain pure rolling without slippage under the condition of consistent angular velocity. In fact, a trace amount of slippage always exists, but under the condition of synchronous rolling, it is required that the amount of this slippage should not exceed a certain amount. Therefore, reasonable lining should be taken in accordance with the requirements of the machine manual to avoid ghosting caused by improper lining.

4. The handover of each unit of the multi-color offset press is not accurate, and the ink of the multi-color offset press is overprinted under the condition of wet pressing, so the ink imprint printed first is easy to transfer to the surface of the rubber cloth with color later. When the positioning and handover between the units is not accurate, the ink blot printed first will be displaced, so that the imprint of each color transfer cannot coincide and cause ghosting. When printing, the paper has to go through many parts from the beginning of the paper feed to the delivery table, and the more times the paper is transferred, the greater the cumulative overprint error, and the more opportunities for displacement, that is, the greater the possibility of ghosting.

Therefore, it is required that the positioning and handover parts between the rollers are accurately positioned, and cannot be loose or worn, so as to ensure that the rollers hand over the paper at the cutting point.

In addition, the cylinder is not in place, the cylinder is overpressed, the quality of the blanket is not good, the peeling of the paper is too large, the printing plate is not tight, or the printing plate is broken at the clamping plate, etc., will cause longitudinal ghosting failure.

I don't think it's very clear.