How to solve the thin paper printing shrinkage
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
In the process of thin paper printing, we often encounter such a phenomenon: sometimes there is a deviation in the horizontal dimension of the printing plate, the error is generally less than 1mm, but sometimes it reaches 3 to 4mm. And the farther apart the unit, the greater the error in lateral overprinting. In addition, sometimes the problem of overprinting is also manifested in the diagonal diagonal of the entire layout, one overprint is intact, and the other end has no small error. Through many years of practice, Anmei Mall found that these problems are mainly caused by the combination of two processes: paper moisture absorption and heat drying.
The printing speed of the gravure printing machine is very fast, the drying temperature is quite high, and the temperature of the paper is basically the same. How can it absorb moisture?
There are two aspects to the moisture absorption of the paper. One is in the unwinding part. After the roll paper is unwound, in the paper head part, the coating on the front side of the paper will hinder some moisture from entering the paper, while the back side will be relatively moist. In general, the paper Will increase 2% to 3% of water. Second, green printing is now advocated, and water-based inks are gradually being applied in gravure, including water-based varnish. If the water-based ink is printed over a large area, the surface of the paper may be temporarily deformed by moisture, and after being dried at a high temperature, the moisture portion may shrink and the lateral size of the paper may become smaller. If the temperature of the oven is heated, the more moisture in the paper will evaporate, the greater the deformation and shrinkage of the paper, and the overprinting will occur when printing the next color. In addition, whether the water content of the paper in the web is uniform or not, if the water content in the front and rear of the paper roll is inconsistent, such a problem may occur.
The solution to the shrinkage of thin paper printing is to appropriately increase the printing speed, minimize the heating temperature, and reduce the unnecessary hot air drying, so that the printing ink color is not anti-sticking and does not fade. In addition, too much paper tension will cause the paper width to change during the paper transfer process, resulting in inaccurate lateral overprinting. However, specific analysis is required when specific problems are encountered.