Problems in Printing and Printing Process

Stencil operators must perform matching tests on exposure and development before daily work to determine exposure time, development time, and developer concentration suitable for printing and proofing. Method: First, ensure that the temperature of the developer and developer concentrate meet the development requirements. Then take a small PS plate and put the signal bar on it to expose the signal strip. Before the test, it is necessary to take into account the different service objects of the printing plate, and the exposure time test should also be adjusted to different degrees.
a. proofing version: the signal bar after exposure and development of the four grayscale requirements sunning half, 2 small spots drying up, 50 points to restore the basic accurate, 80 outlets can not reduce the children and the edges of the network is clear and tidy.
b. Printed version: After the signal bar has been exposed and developed, four levels of gray scales are required to be sunburned by one and a half grades, and two dot-nets are sunburned. The 50- and 80-degree gay and pungent points are restored to be basically accurate and the edges of the dots are also required to be clear and tidy. The main reason for the inconsistency between printing and proofing is to solve the problem of the mechanical performance of the proofer and the printing press, and to ensure that the printed matter and proofs are basically consistent in terms of tone, hue, or saturation. .
Greatly understand the PS version of the performance indicators, the correct use of the PS version in the replacement of the new PS version or use the same manufacturer of the PS version and the batch number is different, because the photosensitive liquid ratio is not the same, the speed will be different, so the exposure The time, the development time, and the developer concentration have to be changed accordingly.
In the use of developer, in order to achieve the ideal development of the theater effect is best to use with the PS version of the matching developer, because the PS plate produced by different manufacturers have strong or weak anti-alkaline properties, if the alkaline weak PS plate with strong alkali The developer is developed, and no photosensitive layer of the photo-decomposed portion is severely affected, and the dots are smaller after the development and the image tone is lost.
When the concentration of the developer is too large, not only the photosensitive layer is corroded, but also the oxide film of the printing plate is destroyed, so that the oleophilic performance of the printing plate is affected, and the printing durability of the PS plate is reduced. If the strong alkali-resistance PS plate is developed with a weakly alkaline developing solution, the phenomenon of incomplete development will occur. When the printing plate is dirty, the aluminum plate base will be subject to certain corrosion due to too long development time, affecting the PS plate. The effect of use.
In addition to dirty, erase rubber, dry developed PS plate to remove dirt. Before removing dirt, the PS plate must be dried first, because most of the dirty areas are close to the image or text, and when the revised paste comes in contact with the PS plate, it is miscible with the surface of the plate and spreads to the surrounding water, which easily erodes the image. Or text, making the edges of the image blank, text lines lighter, or broken. In addition to dirty, use a brush tip to wipe a small amount of patch paste. Dirty spots need to be wiped cleanly and thoroughly removed in the shortest time, and then immediately rinse with water, to avoid the repair paste drying on the surface of the PS plate due to the long revision time.
Revision time is too long to make the layout dirty. After repairing the dirt, it is necessary to timely wipe the protective layer on the PS plate. If the glue is not wiped off in time, the hydrophilic layer of the PS plate will be oxidized and the hydrophilicity will be reduced. When printing, the PS plate will be dirty. Correct squeegee method: Wipe the thin layer on the surface of the plate with a proper amount of the tarpaulin and apply evenly so that all hydrophilic layers are protected. After the squeegee is removed, the PS plate is dried and then protected.
Protection method: Each two PS plates are separated by a neutral moisture-proof paper, and the storage temperature is 25. Around C, relative humidity is around 60.
If the quality of the printing plate is in a stable state for a long period of time, the printing staff must have the spirit of love and respect for the job, continuously accumulate experience in the work, and find a set of scientific standardized data suitable for printing and proofing, so that they can be handy when working to adapt to the current situation. This high-volume printing plate needs drying, which not only improves work efficiency but also ensures product quality.