At present, paper bags are widely used in clothing, shoes, gifts, food, alcohol, drugs and other goods packaging. Some portable paper bag after offset printing, printing gold, silver, hot stamping, plastic film, indentation, folding, binding, holes, eyelets, wear the ribbon multi-channel processes. In order to hand carry paper bag made more exquisite, should pay attention to the following points in print production.
1 Adjust the printing pressure
Portable paper bag often use ration is 250 ~ 400g/m2 whiteboard paper production, paper is thick, for adjusting printing pressure proposed more stringent requirements. The adjustment, the plate cylinder and rubber drum of center distance unchanged, only need to adjust the embossing drum and rubber roller center distance. In the printing quantity is 250 ~ 450g/m2 white paper, the drum of center distance is pulled big 0.20 ~ 0.40mm. In addition, because the surface is smooth white paper, the close degree is not coated paper, therefore, we also pay attention to the printing pressure increase. Printing pressure regulation, can also be the thickness of the lining of the increase and decrease of the rubber roller.
2 Adjust the offset printing paper feeding part
Printing paper, coated paper, white cardboard, kraft paper, because paper is large, so it should be part of the suction nozzle of paper, paper air blowing mouth corresponding larger; the nozzle of paper to replace the rubber ring with larger diameter, thicker; the pressure spring tension gauges can be replaced with larger diameter the model, in order to realize feed does not swing, go to smooth paper.
Printed paper board, gap offset double sheet of controller should be increased accordingly, between the paper pressing tongue side and the former syndiospecific transmission and cardboard to increase some distance. To prevent more than one whiteboard paper jam in the embossing drum and rubber roller, resulting in "stuffy car" fault. Between the double sheet control wheel and the paper feed roller distance of not less than 2 pieces of paper thick, can not be more than 3 pieces of paper thickness, or parking will hog paper through; or double sheet of paper from the controller surface through, and the power supply controller of electric shock is not contact, not to control the double purpose. In addition, it should be cleared up double sheet control wheel, a feeding roller surface and power control at the 2 shock surface dust or insulation, prevent the failure of double sheets control system.
3 Preventing rubbed against dirty
Bag printing often have full field, easy to cause the back rubbed against dirty. Therefore, should try to use the original barrel ink, appropriate and some adhesives, anti adherent, without 6# inking oil, hot weather, do not add dry oil.
In addition, still can use dusting method to solve. It should be noted, dusting will affect the surface gloss of printed matter, and the pollution of the environment, will have an offset printing press and other parts wear, sticky dirty.
Note that the correct arrangement of printing color sequence. In order to avoid imprinted not dry paper collide on the back rubbed against dirty, should first printed text, the line version, and then print edition.
4 Arrangements for the color sequence
In the arrangement of printing color sequence, in addition to consider on the back rubbed against dirty, should also pay attention to the following points.
(1) the first printing halftone, after printing lines, field. When the bag is the four colour printing halftone image, and text, the field patterns, lines, in order to guarantee the overprinter accurate, reduce paper expansion, should first printing halftone printing lines, then, field, and can identify the primary and secondary, the first easy.
(2) the first deep color, shallow color printing. Light color ink covering power weak because, on the back of overprint, slightly misregister, also not easy to detect, printing effect is good.
(3) when the white paper, cardboard, kraft paper, water content is not uniform, wrinkle is not smooth, surface strength, cause the powder, hair loss, can be empty printed on a water to solve the quality accident monochrome printing.