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The quality of thermal paper is determined by the binder and ratio of ink

Time : 2022-04-27 Hits : 5

First of all, look at the appearance of the paper. The thermal paper of good quality has uniform color development, good smoothness, high whiteness and a little greenish. If the paper is very white, then the protective coating and thermal coating of the paper are not reasonable, too much phosphor has been added, if the paper is not smooth or looks uneven, then the paper coating is uneven, if the paper looks reflective The light is very strong, and too much phosphor is added.

Secondly, use fire to heat the back of the paper. If the color on the paper is brown, it means that the thermal formula is not reasonable, and the storage time may be shorter. If the black part of the paper has small stripes or color blocks Uneven, indicating that the coating is uneven.

The thermal paper with better quality should be dark green after heating, and the color blocks are uniform, and the color gradually becomes lighter from the center to the periphery. It is determined by the binder of the ink and its ratio. The drying of the ink is also complicated by the fact that the substrates are mostly paper with a porous surface. In most cases, the drying of the ink is completed in a combination of two or more forms. For example, after the ink is transferred from the printing plate to the surface of the paper, a part of the binder in the ink penetrates into the paper fibers. At the same time, the solvent in the ink begins to volatilize, and the binder on the surface of the paper also begins to undergo chemical and physical reactions. , so that the dryness and hardness of the surface ink film continue to increase, and then the drying process is completed to form a solid film layer. However, due to the different types and ratios of binders in the ink, the ink is also dominated by a certain drying form to complete its drying process. Due to the low overall ambient temperature, when the machine is just turned on in the morning, the temperature of each part of the machine is low. The printing operator must do the following two points before starting the printing.

First, increase the temperature and humidity of the workshop to make it meet the standard (the temperature is 20-24°C, and the humidity is 60%-70%).

Second, heat the ink or add additives or varnish to the ink to increase the fluidity of the ink, and then turn on the machine.

This is because even if the ambient temperature and humidity are just up to the standard, the temperature of the rollers of the printing press is still at a low level, which will lead to the weakening of the ink transfer performance, which makes the printing press unable to ink well, the printing speed is very slow, and the stability of the ink color is difficult to control. . It is necessary to increase the ink supply to twice the usual printing of the same job, so that the ink color of the printed product can barely look saturated; or the entire layout is gray; or when printing thinner paper (105g/m2 and below), the paper is very easy Sticking to the blanket, causing the blanket to be crushed.

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