Paper quality caused by print quality problems

With the increasing demands of people, a variety of processes are widely used in outer packaging, which makes the products colorful and dazzling, causing consumers to have a great desire to purchase. However, due to factors such as materials, process technology, equipment, and environment, such phenomena as missed printing, wrinkling, faded ink, embossing rollers, and printed matter are contaminated. The paper as a printed matter, its own nature, the performance of the ink, the density of printed graphics, etc., have affected the quality of printing.

1, missing print

In the calendering section of a paper machine, the occurrence of paper breakage due to the occurrence of broken paper is common. These pieces of shreds should be removed during rewinding and slitting. If there are scraps of paper caught in the paper, it will cause missing prints and malfunctions during printing. Paper mills often do not pay much attention to the problem of one or two pieces of shredded paper in the paper. They think that there is no big impact. In fact, shredded paper will bring great troubles to the printing industry and cause greater economic losses. When printing on web or flatbed paper, if there are scraps of paper in it, these scraps of paper will adhere to the surface of the paper and enter the printer. The printing pressure and the viscosity of the ink will cause the shreds of paper to adhere to the blanket cylinder. Or layout. In this way, the text and images on the printing plate cannot be transferred to the paper, so that the printed matter forms missing printing (commonly known as window opening). On high-speed printing presses, once this happens, tens or even hundreds of prints can be made waste, and the need to shut down the scraps of paper from the squeegee or on the plate can make the loss even greater.

2. The impression cylinder and printed matter are contaminated

This contamination is often caused by holes and folds in the paper.

Holes are small holes that can be seen through the paper with the naked eye under light. Big hole called hole. Paper with holes may cause problems with the quality of missing pens during printing. When there is a large hole or hole in the paper, the ink on the printing plate or blanket cylinder is transferred from the hole to the impression cylinder, so that the printing roller continuously transfers the ink to the other side of the printed product while continuing to rotate. Damage to prints. When the ink is transferred to the impression cylinder, if the viscosity of the ink is high, the paper will also be stuck on both sides and be torn off. The torn paper sticks to the blanket cylinder or plate, and the printing failure caused by the scrap paper mentioned above also occurs.

The folding angle refers to a corner of the printing paper coming back. The folding angle also causes serious printing failure. Kok can be divided into two kinds of dead fold and live folding angle. When printed with folded corners, the printed matter on the sheet is not printed on one sheet, and one sheet is printed on the back. In addition, the ink is also transferred to the impression cylinder at the corner portions, causing the impression cylinder to continuously contaminate the back side of the print, resulting in a lot of scrap. Even more serious is that if the paper is thick and stiff, the folded corners may also damage the blanket, forcing downtime change.