(3) Dark tone (dark part) is too deep. Cause: The plate is too deep. Countermeasures: Due to the lack of ink drying, the ink layer may be agglomeration, and if necessary, it must be reprinted.
(4) Shadowing density is not enough. Cause: The plate is not deep enough. Countermeasure: Use dark color ink.
(5) The depth of the intermediate tone ink is clearly at the junction. Cause: Poor ink. Countermeasure: Replace ink with good characteristics.
Sixth, the Indian ink dried conjunctiva bad (1) hot air temperature, wind speed, air volume, exhaust capacity is insufficient. Countermeasure: Adjust the drying device.
(2) After printing, the ink layer has the illusion of dry conjunctiva. The ink layer still contains residual solvent. After the film has been rewinded, there is also residual heat at about 40° C., which is suitable for the solvent to continue its activity, and the pressure at the time of rewinding has a certain amount of pressure, thereby causing the danger of back tackiness. Countermeasures: 1 After printing, the ink layer should be thoroughly dried; 2 After printing, the film should be loosely collected in a wire basket. After the film cools, the film will be rewinded, cut, and bagged when it is tested for no stickiness.
Seventh, the reason why the gloss of printed products is light: The ink is diluted too much. Countermeasures: Control the amount of diluent.
Eight, the edge of the imprinting is not smooth, the background is speckled Cause: The viscosity of the ink is too low, and the solvent is used in excess.
Countermeasures: Add new ink to increase viscosity.
Nine, printing layer from the orange peel markings reasons: ink drying too fast, the concentration is too light, poor leveling, thixotropic, static electricity, printing speed is too slow. Countermeasures: Find out the reasons and take corresponding measures.
Ten, there are scratches on the printing layer Causes: The guide roller is scratched, the ink is mixed with sand, the doctor blade is uneven, and the angle between the doctor blade and the printing plate is not proper. Countermeasures: Corresponding processing.
Eleventh, the hue is thin:
1 Ink color is thin;
2 color light reflection is poor.
Countermeasures:
1 adjust the ink;
2 The surface of the watch is first laid with white ink, and then it is color-matched. In India, the first edition was printed with three primary colors, and the background was finally laid.
Twelve, bite color in the overprint, the second color ink sticky pull off the first color ink.
Reason: After the first color ink layer is not completely dry, the second color pressure is too large, or the machine speed is too fast, or the cold and hot air is bad, the substrate printing is poor, all can cause bite.
Countermeasures: Find out the reasons and take corresponding measures. 1 Add an appropriate amount of quick-drying agent; 2 slow down the speed; 3 reduce the pressure of the impression cylinder; 4 add too cold, hot air volume.
Thirteen, rough prints, blank spots, full version, moire in the field, tune is not full.
the reason:
1 too much solvent;
2 thicker ink;
3 ink is too thin;
4 volatile;
5 poor ink fluidity.
Countermeasures:
1 reduce the amount of solvent;
2 replace the ink or re-grind;
3 adjust the ink thick;
4 Slowly dry the solvent
5 Replace the ink.
In addition to the phenomenon of blockage caused by the chemical reaction caused by the ink itself (uncommon), the remaining factors are summarized into five points:
1 During printing, the viscosity of the ink increases with the evaporation of a large amount of solvent, and it is extremely easy to dry in the interior of the cell. If it is not cleaned in time, it will cause serious blockage.
2 In the printing process, if the position of the scraper is far from the printing roller or the angle is not reasonable, the diameter of the printing roller is large, or the depth of the platen roller entering the ink tank is not enough, the hot air blown from the dryer affects the roller surface of the plate, which may cause serious jamming. Version.
3 ink mixed with impurities.
The engraving depth (or photogravure corrosion depth) of the 4th edition roller network wire is not suitable.
5 When printing, the temperature is too high to make the solvent in the ink volatilize too quickly, which also causes the layout to jam. ("Printing Magazine" Xue Zhiyong)