Gravure printing is a plate making technology in which the image is carved from the surface. Generally speaking, using copper or zinc plate as the surface of engraving, the concave part can be etched, carved, copperplate or mezzotin metal plate making method, and Collagraphs may be printed according to gravure plate. To print a gravure plate, the surface is covered with ink, and then the ink is removed from the surface with a taltamb or newspaper, leaving only the concave part. Wet paper is placed on the top of the plate. The plate and paper are pressurized by the press to transfer ink from the concave part of the plate to the paper.
1、 The electrostatic problems caused by gravure printing are as follows:
1. Whisker - ink flies out of the edge of printed patterns or characters, in the form of a beard;
2. Spot marks in the field printing part often appear at the depth of 5-20 μ m. This is because the ink on the printing film has been affected by static electricity and moved before drying;
3. Edge rejection - occurs when intaglio is overprinted. The film junction of the first color ink and the back printing ink can not match well with the second color ink, resulting in rejection, resulting in a white edge between the two colors.
2、 In gravure printing, static electricity comes from the following aspects:
l. Its own BOPP film with a lot of static electricity, can be replaced by different manufacturers of film or electrostatic treatment, and then use.
2. In the process of printing, the electrostatic failure mainly includes the following aspects:
① In high-speed printing, the friction between BOPP film and rubber roller for a long time produces a lot of static electricity;
② The climate is dry and the humidity is too low;
③ The characteristics of the ink itself or its own anti-static ability is insufficient, resulting in static electricity;
④ The anti-static device of the equipment has failed to work and can not eliminate static electricity.
3、 The electrostatic fault can be considered or handled from the following aspects:
1. Regularly check whether the anti-static device of the equipment can play an anti-static role;
2. In the dry season, the printing environment should keep a certain humidity;
3. Try to choose the printing film without static electricity, or eliminate the static electricity on the printing film;
4. In the diluted solvent, add polar solvent, such as butanone, isopropanol, ethanol, etc., and use less ethyl ester. In the process of BOPP film printing, 5% - 20% isopropanol can be added to BOPP film ink to eliminate static electricity in the printing process
5. In the actual printing process, AE-2 super concentrated electrostatic agent or 3500a antistatic agent can be added to solve the "whisker" static electricity. For the "edge exclusion" problem, the printing viscosity of the ink can be appropriately increased or bk-201 and bk-202 additives can be used to solve the problem;
6. When designing the formula of ink, the ability of eliminating static electricity should be fully considered. 2% ～ 8% ISO acetone, 0.1% ～ 0.5% AE-2 super concentrated antistatic agent or 0.5% ～ 2% 3500a antistatic agent should be added to the formula.
The above information is edited by Dongguan Beite packaging material Co., Ltd www.dgbpk.com