The causes and solutions of the most popular print

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Causes and solutions of white cracks in printing plates

the main reason is the poor mutual solubility of wax surfactants in the ink system; The second reason is that the ink was not redissolved during ink "> printing after the ink was crusted. This hardness tester (rubber hardness tester) is widely used for hardness measurement of rubber and plastics and was transferred to the image and text.

treatment method: aromatic hydrocarbon or ester real solvent should be added to promote its dissolution again. Or an agitator should be installed in the ink bucket (if plastic pipes are used, cover the outside with unprinted plastic film, tie the two ends tightly in the ink head and rotate them randomly to mix the ink), or add antioxidant treatment during ink manufacturing

II. Dot type white dot

mainly caused by static electricity of ink or substrate. Or it is caused by the static electricity generated by the diluted solvent (the resistance varies with different solvents). It usually occurs when the temperature is high or the printing speed is fast. Secondly, when laminating, it is tight in front and loose in the back or loose in front and tight in the back, and the cause of static electricity is common in high humidity weather

treatment method: add an appropriate amount of antistatic agent in the ink (excess will affect the composite fastness), select a solvent with low resistance to dilute the ink, and adjust the laying and receiving of grounding wires (generally 700 ~ 1500mm deep)

III. crack whitening

one of the main reasons is that the ink transfer performance is too poor, and the other is that the printing plate pattern is too shallow, which makes the solvent in the ink system volatilize too quickly

generally, rough imprinting leads to poor film formation, especially the whitening caused by the addition of water in the ink system or ink bucket diluent, which mostly occurs in the environment with too high humidity in the workshop in summer

treatment method: replace the ink with good transferability or replace the deep printing plate, and add slow dry solvent for treatment

IV. albinism of the whole block

main reasons:

1. When the continuous printing time is too long, when the operator finds that the ink viscosity becomes sticky or thick, he repeatedly adds a single solvent, thus breaking the volatile transfer material of the mixed solvent in the original ink system, which has become a fundamental problem. The chemical industry is expected to balance, resulting in rough and white ink layer when the printing ink forms a film

2. Even if the operator adds mixed solvents, excessive addition often reduces the content of synthetic resin in the ink, and the above whitening phenomenon also occurs

processing methods: first, add 3% ~ 7% slow dry solvent, especially the real solvent that can accurately and reliably capture and convert the measured original information without a sensor to plasticize the ink and resist the invasion of water molecules; Second, select special diluent containing resin; The third is to add 5% ~ 15% ink blending oil to the ink to overcome the whitening caused by insufficient resin content. The fourth is to install a central air conditioner capable of regulating temperature and humidity in the workshop or use a moisture absorber to eliminate it

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