Analysis of the Causes of Low Printing Force Resistance of Printing Plates

The low resistance of the printing plate to the printing press creates troubles for the offset printing operation and directly affects the quality of the printed product. There are many factors that determine the printing plate's resistance to printing force, which is analyzed in several aspects for reference by peers.

First, the quality of printing itself

There are various kinds of printing plates on the market, and the quality is uneven. We should carefully select different varieties to suit different printing requirements. When choosing, pay attention to the composition of the plate base; whether the thickness of the photosensitive resin film is the same; whether the plate grain is too thick or too sharp. Selecting a good quality plate is a prerequisite for improving the printing plate's resistance to printing. However, if the plate is stored improperly, exposure to bright light causes trace exposure, or storage time is too long and damp, resulting in oxidation of the plate caused by the decline in smoothness, even the best plate can not guarantee the printing plate resistance to force.

Second, the technical problems of the plate making process

The density of the film used in printing is generally 3.8 or more. The developer should be stirred evenly, the level of water should be appropriate, the temperature should be appropriate, attention should not be over-developed, the developer must maintain balance, and the blade rotation speed is uniform.
The layout should be thoroughly finished. When cleaning the paste after revision, wash it with a large amount of water and wipe it at the non-image area, which will not lead to local resin film thinning. The baking temperature should not be too high and cannot be excessive. Only by strictly following the technical requirements of the plate making process can the printing plate maintain a high resistance to printing.

Third, the problem caused by improper adjustment

When loading the plate, it is necessary to pay attention to the foreign matter before the printing plate, and keep proper thickness of the printing plate gasket to adjust the pressure between the printing plate and the water roller, blanket, and ink roller so as to avoid too much force between them. During commissioning, the machine should not idle for too long when the platen is not inked. When the dirt on the plate is wiped with the wetting powder, do not apply excessive force to the graphic portion to avoid damaging the plate resin film. Also pay attention to the aging water roller sleeve or blanket do not continue to use. If there are too many ink deposits on both sides of the blanket and on the tail, it should be scrubbed clean, and the blanket should be scrubbed carefully after each change of plate. Water rollers should also be often washed with cleaning agents or gas oil. After washing, the water roller cover must not leave any detergent or gasoline residue. The ink that is hardened by the plate roller should be scraped cleanly. Should not use too hard liner, uneven liner should be flattened or replaced, so as not to cause serious wear and tear on the printing plate, blanket should be given too tightly fixed, especially after the replacement of the new blanket and liner after a period of time Loose phenomena will occur and should be tightened in time. At the same time, pay attention to the consistent tightness of the blanket canyon to avoid over-tight at one end and loose at one end.

Fourth, the problems caused by machine wear

The roller sleeve of the printing press wears badly, the amount of turbulence is large, and the impact force on the printing plate increases during printing, which directly leads to the reduction of the printing resistance force. For example, relying on the printing roller, the amount of turbulence increases the force of the printing. If the printing volume increases the force of printing, if the printing speed does not decrease, the position of the printing plate will soon be damaged. In this case, the corresponding parts should be replaced or properly repaired. Less serious, rubber cleaning reductant can be used for cleaning. At the same time, the speed should not be too fast when printing.

Fifth, paper, ink and liquid problems

If the paper has too much paper, sandy soil or sand, and the pH is too high or too low, it will affect the blanket and plate. The pH value of the bucket at night should be kept between 5 and 6 during printing, and the bucket should be cleaned frequently to prevent deterioration and deterioration of the printing plate life. The ink should be adjusted properly according to the requirements of different types and different prints, such as ink-adjusting oil and dissolving agent, so as to prevent the viscosity of the ink from being too high and to reduce the printing-resistance of the printing plate. Since the ink itself does not necessarily protect the printing plate resin film, when printing, care should be taken that the amount of ink used is not too small, otherwise it is also easier to abrade the printing plate. If the rubbed version of gauze is used for too long, it should be replaced.