Case Analysis: Elimination of Special Dirty Prints
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
It was found that half of the central part of the printed tip was round and dirty, and it was red, yellow, blue and green. Wiping the plate with a wetting powder, no effect. It is thought that there is oil on the presser foot, which causes the oil on the upper plate to cause dirt. Therefore, the presser foot and the mouthpiece are wiped with a cloth, and the dirt remains. The position of the dirty surface on the surface of the plate is scraped with a razor bar, then etched with phosphoric acid, printed, and dirty. Suspected to have a relationship with the plate, changed the new version, the upper body is still. Since the position of the dirty trace coincides with the position of the presser foot, it means that it is related to the presser foot, so the presser foot is inspected, and it is found that the copper except the presser foot is different from the past, and there is no other abnormality. Is it related to copper? The presser foot used in the past is made of brass, and now it is replaced by a red copper product. The difference between the two is that the red copper is soft. The red copper presser foot was replaced with brass, and the layout was re-processed. When the print was printed, the dirt was completely eliminated.
Why is this happening? We think that it may be because the red copper texture is soft, and some fine particles are ground by the rough paper in the printing. After being brought into the printing plate by the paper, it is affected by other factors, and a chemical reaction occurs, so this intractable dirt appears.