In the packaging and printing industry, the self-adhesive trademark is mainly to meet the needs of convenient pasting of commodity brand labels. A layer of self-adhesive layer is evenly coated on the back of the paper, and then a layer of wax paper that is easy to peel is pasted.
There are two types of self-adhesive: roll and sheet. The commonly used self-adhesive trademarks are printed on the web and die cut with a knife line after printing, and the blank and excess parts are stripped. When in use, a printed matter of a certain shape is left on the wax paper. As long as the finished product is stripped and pasted directly on the commodity or package, it is very convenient and fast except coated paper and other papers. The self-adhesive trademark also includes self-adhesive prints based on aluminum foil, gold card, silver card and color polyester film.
1. Characteristics of self-adhesive printing
Our factory often uses four and eight offset presses to print self-adhesive trademarks, packaging and decorative products. The differences between self-adhesive printing and other printing methods are as follows:
1. The self-adhesive paper is thick, generally two 150g / m2 coated paper, which is composed of coated paper, aluminum foil, color polyester film printing layer and wax paper layer，Key points of self-adhesive printing process
2 self adhesive printing paper is generally high-grade coated paper, gold card paper, silver card paper and color polyester film, and the paper surface is smooth
3. Low ink absorption of self-adhesive paper，printing large area images on the full plate is easy to dirty the back.Key points of self-adhesive printing process
2. Several problems needing attention in self-adhesive printing
adjust the printing pressure during offset printing, the two adjacent rollers of the printing plate, rubber and embossing rollers contact and squeeze each other to transfer printing, so as to realize the normal transmission of ink on the printing paper and truly reproduce the continuous tone text, lines, lines, images and halftone points of graphics. These impressions must bear the necessary printing pressure, In addition to the contact between the two roller surfaces, the weight of the printing pressure and the accuracy of adjustment will directly determine the size, the depth and quality of the ink.
In graphic transfer and printing dot reproduction, the center distance between the embossing roller and the rubber roller needs to be adjusted during self-adhesive printing. If the paper becomes thinner from thick, the center distance of the roller can be increased by about 02-04mm, The thickness to be reduced is to add the pad thickness removed from the plate pad to the rubber drum; If the paper thickens during printing, subtract a certain thickness from the rubber cylinder liner and add the corresponding thickness to the plate cylinder liner
During the printing process, in production practice, in order to prevent relative slip in the printing process, it is necessary to press and compact, and the ideal printing pressure is generally controlled at about 015-025mm. It must be emphasized that the ideal printing pressure is to make the impression of the graphic part of the printing plate on the paper firm enough under the condition of certain compression deformation on the printing surface, and the minimum pressure is adopted on the basis of clear and complete dots.Key points of self-adhesive printing process
when printing self-adhesive, pay attention to the adjustment of the paper feeding part, and the air volume of the paper suction nozzle and paper blowing nozzle of the paper feeding part shall be increased accordingly.Key points of self-adhesive printing process
the paper separation suction nozzle and paper feeding suction nozzle shall be replaced with rubber band with large diameter and thickness, so as to achieve the purpose of stable paper feeding and no swing of paper feeding roller
since self adhesion is the thickness of two layers of coated paper, the paper thickness should pay attention to the corresponding increase of the gap between the two page controller, and the distance between the side gauge and front gauge pressing tongue and the paperboard should be increased。
the distance between the paper transfer tooth pad and the surface of the embossing cylinder, and between the paper transfer tooth pad and the paperboard shall be increased, and shall be kept about equal to the paper thickness plus 03mm.Key points of self-adhesive printing process
3. Color sequence arrangement of self-adhesive printing
Self adhesive printing products have full version domain, as well as words, lines and patterns. For example, for printing products such as wine boxes and drug trademarks, it is best to first print words, lines and patterns according to the color sequence of printing, and then put the full version on the ground for final machine printing, so as to avoid the phenomenon that the paper collides and rubs with each other and the back is sticky due to the thickness of self-adhesive paper.Key points of self-adhesive printing process.