Flexo Printing and Platemaking (2)

Fourth, the production of flexible version At present, the flexographic printing used in the plates are basically solid photosensitive resin plate, the photosensitive mechanism is: the photosensitive resin under a certain amount of light irradiation, the rapid decomposition of the molecules, resulting in lively and extremely unstable The high-energy radicals (radicals) and high-energy radicals re-initiate polycondensation of the unsaturated bond-containing resin. The flexographic platemaking process mainly includes the following processes:
1. The backside exposure of the plate is to determine the height of the relief on the plate, ie the depth of corrosion, and to cure the substrate.
2. Put the printing plate and the negative film together, use the ultraviolet light for front exposure, form the graphic part on the printing plate, and make it solidify.
3, the printing plate is placed in a solvent brush, the purpose is to brush the unexposed part of the plate material, so that the graphic part of the relief.
4. The printing plate is dried in a dryer to promote the volatilization of the solvent absorbed in the printing plate as soon as possible so that the thickness of the printing plate can be restored to its original standard value.
5, after the exposure and detackification processing. The post-exposure and de-tack treatment of the dried plates can further solidify the shoulders and bases, improve the flexographic printing performance, and increase the flex print resistance.
V. Points to note in the flexo platemaking process:
1. Try not to place fine details such as small prints, dots, etc. on a large area on the ground. Even the same color should be divided into two editions. If it is impossible to separate them (for example, the number of printer color groups, etc.), consider Appropriately make padding locally.
2, try to avoid large areas of real-color multicolor overprint.
3, the text specifications can not be too small, even more so with the negative text, otherwise, when the print pressure changes, the printed text shows a larger amount of deformation, so that Yang Wenwen thicker, Yin Xie text thin or paste dead.
4, the width of the independent fine lines should be greater than 0.2 mm.
5. In the flexographic printing, the engraving angle of the ink hole on the anilox roller is generally 45°. Therefore, when the ordinary anilox roller is used for printing, the printing plate should avoid the 45° angle of the cable. Avoid print moire.
6. Avoid designing wide and long bars and solids in the horizontal direction of the print cylinder. This can cause machine vibration. Ideally, slashes, curves, wave lines, and other irregular curves.
7, the layout to avoid designing a larger circular pattern. Because when the plate is elastically stretched or elastically compressed, the regular geometric pattern becomes irregular and the circle becomes elliptical.
8, to avoid the strict requirements of strict seams.
9, the original color to take into account that the press can print a few colors.
10, in the use of ink stack color, should not use two equal color blocks overlap printing, in order to avoid overprinting is not allowed to affect the printing quality. It is possible to use overly large areas of solid patches to overprint text or patterns and to overprint local patches.
VI. Common Problems and Solutions of Flexo Plate Making 1.
1) The plate is not cleaned after rinsing;
2) The rinse solution has been used for too long or has insufficient active ingredients.
Solution:
1) Plate flushing corrosion, and then thoroughly clean;
2) Replace flushing solvent.
2. The straight line is not straight, curved or wavy:
1) After exposure is not sufficient;
2) Insufficient main exposure;
3) Insufficient drying time.
Solution:
1) Adjust the exposure time;
2) The main exposure time is tested again;
3) Increase the drying time.
4) Missing fine text and thin lines.