Cylinder lining and pressure adjustment
Printing double gray paper plate cylinder and rubber cylinder center distance remains unchanged, only need to adjust the center of the impression cylinder and rubber cylinder, in the printing of 250-450g/m2 double gray paper can be pulled up the cylinder center distance 0.20-0.4mm, due to the double gray paper surface smoothness is poor, relatively rough, the tightness of the paper is also far less than Copperplate paper, printing double gray paper, but also pay attention to the printing pressure is correspondingly increased a little.
Such as printing 400g / m2 of double gray paper, printing plate cylinder and rubber cylinder gap of 3.95mm, rubber cylinder and embossing cylinder gap of 3.40mm, printing plate cylinder total package village of 0.65-0.75mm, rubber cylinder total liner of 3.15-3.35mm (measured with a micrometer), if Paper from thick to thin, should be reduced by the thickness, the thickness of the package liner from the printing plate liner to add to the rubber cylinder, if the printing paper from thin to thick, then from the rubber cylinder liner to reduce the thickness of a certain, and the corresponding thickness to the printing plate cylinder liner to go.
Offset printing part of the adjustment of the paper delivery
1, double gray paper printing to the paper delivery part of the suction nozzle and blowing paper nozzle wind volume accordingly to adjust the larger.
2, the paper dividing nozzle, paper feed nozzle to replace the larger diameter and thickness of the rubber ring, pull gauge compression spring can be replaced with a diameter of 1.5mm steel wire; by removing the coupling pin between the feed roller cam and its shaft, or remove the roller on the pendulum to achieve the purpose of the paper feed roller does not swing, smooth paper.
3、When printing double gray paper, the gap between the double control or of the offset printing machine should be increased accordingly; the distance between the side gauge and the front gauge of the pressure paper tongue and the paperboard delivery, and the distance between the safety bar and the paperboard delivery should be increased some.
4, handing the paper tooth pad and the surface of the impression cylinder and handing the paper tooth pad and the distance between the paperboard should be increased, and keep the distance approximately equal to the thickness of the paper plus.
Printing the color sequence arrangement
1, double gray paper printing products have Hong Kong version of the field, and text, lines, patterns. For example: the postal sector's special delivery envelopes, wine boxes, cigarette boxes outer packaging (strip boxes) and other printing products, printing color sequence is best to print text, lines, patterns, and then the full version of the field on the last machine printing, so you can avoid the double gray paper thicker, the print is not dry when the paper collides with each other caused by touching dirty rubbing bad, back sticky dirty phenomenon.
2, the dark color on the front of the print, light color on the back of the print, due to the dark color ink coverage, strong adhesion, put in front of the first print, easy to overprint accurate; light color ink coverage is weak, put in the back of the print quantity printed slightly run rule is not easy to observe out, the overprint effect is much better.
3, often in a printed product, there are half-tone four-color electric points of the network, and continuous tone patterns, text, lines. Four-color electric points of the dot should be printed first, which is conducive to accurate overprinting and reduce the impact of paper stretching. Then print continuous tone patterns, text, lines, the arrangement of the printing color sequence should be recognized as the main priority, first difficult after the easier more appropriate.
4, such as hot weather, double gray paper printed monochrome when encountering uneven water content of paper, wrinkled uneven, poor paper surface strength, etc. caused by falling powder, hair, etc., can also first hit the empty print a water, can solve the phenomenon.
Post time: Jan-03-2023