In the process of gravure printing, some printing faults caused by machinery, process raw materials, working environment and other factors often occur, which will affect the product quality and production progress. Here are some common questions for your reference.
Fault seven ink color is not uniform
reason:
(1) ink groove structure is problematic, ink tends to precipitate or generate large amount of foam.
(2) Drying box air leakage, so that the ink solvent quickly volatilization;
(3) Solvent and ink are not completely dissolved.
resolvent:
(1) Improve the ink circulation system, ink can not be too fast, appropriate amount of defoamer added;
(2) Find out the air leakage of drying oven and remedy it;
(3) Choose solvent with strong solubility.
Fault eight fold
reason:
(1) The pressure of imprint cylinder is unbalanced;
(2) The paper guide roller bearing is worn or the locking screw is loose;
(3) The plate shaft is eccentric.
resolvent:
(1) Correct both sides of the imprint drum to make the pressure balance;
(2) Replace the bearing and reinforce the locking guide roller;
(3) Check whether the transmission gear is worn, whether the teeth are stable, whether the plate shaft is deformed, whether the bearing is "burnt out", and correct it.
No. 9 printing is not accurate
reason:
(1) The temperature and humidity of printing workshop are improper, the temperature of drying box is too high, and the paper shrinkage is serious;
(2) Improper arrangement of printing color group, the hardness of front and rear imprint roller rubber is different;
(3) The transmission gear and the plate shaft are not locked, resulting in the plate cylinder displacement;
(4) The automatic tension device has failed.
resolvent:
(1) Keep the printing workshop constant temperature and humidity, reduce the temperature of drying oven;
(2) Arrange the technological process correctly and unify the rubber hardness of the imprint roller;
(3) Draw a line to check whether the transmission gear and the plate are slipping, and lock them;
(4) If the automatic tension device fails, ask the electrical personnel for maintenance.
Fault ten imprinting crystallization (pulverization)
reason:
(1) Excessive ink dilution;
(2) Printing pressure is not enough, ink layer is not solid, resulting in imprint easy to fall off.
resolvent:
(1) Observe whether the ink is turbid and separated from each other. If normal printing cannot be carried out after adjusting the viscosity, contact the ink supplier;
(2) Increase the printing pressure to make the ink solid.
Fault 11 gold ink overprint on spot color
reason:
(1) Due to the coarse particles of gold powder and large ink flow, the ink layer is too thick and the ink storage is large, which is not easy to dry;
(2) Printing pressure is too high, forming extrusion;
(3) The depth of the cylinder is not enough;
(4) Ink drying is not enough.
resolvent:
(1) Add appropriate amount of fast drying solvent in gold and slow drying solvent for spot color. If the printing effect is not affected, the ink viscosity should be kept as appropriate as possible;
(2) The printing pressure should be moderate and balanced;
(3) When making plate, the depth of net hole should be determined according to the situation;
(4) For large area gold printing, the machine speed should be reduced and the ink drying time between color groups should be increased.
Fault 12 adhesion color mixing
reason:
(1) Use viscosity of the main ink;
(2) The ink is not dry enough;
(3) Incorrect printing pressure;
(4) Ink adhesion, cohesion is very poor.
resolvent:
(1) Reduce the viscosity of the ink, control the use of slow volatile solvent, know the volatile speed of commonly used solvent in gravure printing, and fully heat and air supply to make the ink fully dry;
(2) Reduce the printing environment temperature;
(3) Properly increase the machine speed, reduce the color and color overprint, ink stripping force.
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