Viscosity And Fluidity Of Offset Four-Color Inks
Published on Nov. 06, 2018
The viscosity and fluidity of CMYK 4 Color Process Offset Printing Ink play an important role in print quality. The fluidity and viscosity of the offset four-color ink are closely related. The viscosity of the ink increases the fluidity while reducing the fluidity. On the contrary, the fluidity is improved. The ink with a large consistency is not equal to the viscosity, and the ink with a large viscosity is not necessarily thick. For inks with the same viscosity, the greater the consistency, the worse the fluidity.
If the fluidity is too small, the transfer of Offset Printing Ink during the printing process is not smooth and uneven, resulting in shallow front and back and other ink failures on the same printing surface; the fluidity is too large, the imprint cannot be accurately transferred, and the graphic level is not clear. The ink is not full, the color is not bright, and at the same time, the excessive fluidity of the ink can lead to frequent dirty plates and ink sticks. In the printing process, the viscosity and fluidity of the ink can be adjusted by using ink adjustment, but it is forbidden to add corn flour to the ink in order to make the print dry quickly. It is also possible to achieve this by using a fast drying ink. Therefore, the viscosity and fluidity of the ink should be adjusted during the printing process. The preservation of ink has always been a headache for printers. Because the ink is placed in the air for a long time, it is easily oxidized by air to form a thick layer of ink. When printing the next ink, it must be The ink is scraped off, which inevitably wastes a part of the ink. The general measure taken by the printing house is to add a certain amount of water to the ink cartridge to prevent the ink from coming into contact with the air. However, in fact, the oxygen contained in the water will also oxidize the ink, and the contact time between the water and the ink is easy to emulsify the ink. When printing on the machine, there is a phenomenon that no ink is applied, although the amount of ink is large, but uniform The ink roller (mainly the hard roller) is still not inked.
It is recommended to use wax paper to isolate the ink from contact with air during ink storage, or use plastic paper to seal it. Apply wax paper or plastic paper to the surface of the ink layer, and remove the wax paper or plastic paper before the next printing, but it is best. Do not use plain paper to seal it, and avoid the trouble of tearing the paper when uncovering the paper.