Causes and Countermeasures of Eight Kinds of Common Film Gravure Faults

【Chinese Packaging Network News】 This paper comprehensively sorts out the causes and countermeasures of the eight kinds of common faults in the process of film gravure printing so as to facilitate the viewing of problems encountered by everyone.

Eight plastic film gravure printing fault elimination

1, color is not allowed

(1) The film tension changes, so that the vertical printing registration changes.

Each tension control device should be adjusted, such as adjusting the reel brake of the unwinding device; reasonably setting the rotation speed of the roller; increasing the roller surface friction; adjusting the winding tension of the rewinding machine.

(2) The printing roller has a difference in diameter, and the diameters of the one, two, and three color printing plates are successively increased or reduced in diameter, causing a change in vertical printing registration.

Should be re-plate.

(3) The density of the rule line is insufficient, and the printing registration color is shifted longitudinally.

The photocell sensitivity should be adjusted and the plate's paste failure should be eliminated.

(4) The guide rollers are not parallel, the printing pressure is not balanced, and the taper of the printing plate cylinder and the printing platen roller are problems, which causes the film to swing laterally and loose on one side, causing instability in the transverse color registration.

Should make targeted adjustments.

(5) Loosening adjustment screws at the shaft end of the plate cylinder cause instability in transverse color registration.

The tightness of the screw should be readjusted.

(6) If the contact pressure between the rubber roller and the flower roller is too large, the printed pattern will produce a double pattern.

The contact pressure should be adjusted to make the printed pattern clear.

2, the printing surface has spots

(1) The ink viscosity is too low or poor flow.

The viscosity of the ink should be properly adjusted so that the viscosity of the ink is moderate and the fluidity is good.

(2) The plate depth is too deep or the blade angle is not properly adjusted.

Squeegee angle should be adjusted or re-plated.

(3) Improper control of printing pressure.

Should be adjusted properly.

(4) There is too much surface static electricity on the printed material.

Static electricity should be eliminated.

(5) Bad ink drying.

Drying should be strengthened, such as improving ventilation and drying conditions.

3, the printing surface blisters

(1) If the surface of the ink is already crusted and the internal ink is not dry, once it breaks through the crust it will form volcanic vent-like cells, mainly due to rapid drying.

Low-temperature, high-temperature, and low-temperature drying routes should be adopted, and slow-drying inks should be used as much as possible.

(2) During the printing process, a large number of air bubbles are generated in the ink hopper, and the air bubbles adhere to the printing roll, so that the halftone dots of the print pattern disappear or the pattern is stained.

The ink should be kept at an appropriate viscosity, the drop of the ink should be minimized, and a circulation pump should be used to prevent bubbles from entering the ink.

4, the printing surface has a pear pattern

If overprinting on a dried printed surface, the background ink is dissolved and partially mixed with the second color ink, the printed surface will produce a pear pattern.

One is to properly adjust the viscosity of the ink; the second is to properly control the drying speed; the third is to reasonably determine the depth of printing.

5, poor ink absorption

When the surface of the product film is printed in multicolor, when a second color ink is printed on a color coating film, if malabsorption occurs, the dots after the ink transfer will become independent one by one, forming a deeper color of the dot. Misalignment of light in other parts. This has nothing to do with the amount of ink transferred or the problem of inconsistencies, and is mainly related to the diffusion of ink after transfer.

In this regard, one is to use a lag solvent in the second color ink; the other is to move the second color ink squeegee position closer to the printing pressure direction; thirdly, the ink of the second color should be lightly pressed as far as possible; and fourthly, it is properly deepened. The depth of the second color; Fifth, the use of reducing agents in the background ink; Sixth, the appropriate increase in printing speed.

6, the printing roller wear too fast

(1) The blade is too thick.

Thin blades should be used instead.

(2) The contact pressure between the blade and the printing roller is too large.

The contact pressure between the two should be adjusted appropriately.

7, blade wear too fast

(1) The blade is too thin.

Use a thicker blade instead.

(2) The contact pressure between the blade and the printing roller is too high.

The contact pressure between the two should be adjusted appropriately.

8, version network plug

(1) During the printing process, the viscosity of the ink increases with the evaporation of a large amount of solvent, which causes the ink inside the network cable to clog up.

Dry ink should be removed regularly.

(2) When the position of the scraper is far from the printing roller, the diameter of the plate roller is large, or the depth of the plate roller entering the ink tank is insufficient, the hot air blown from the machine affects the ink on the surface of the printing roller, which may easily cause severe blocking.

Should make targeted adjustments.

(3) Impurities are mixed with the ink to cause blockage.

Should remove impurities and filter ink.

(4) During the printing process, the operating temperature is too high, resulting in the solvent evaporation speed in the roller network cable is too fast, causing the plate network to clog.

Try to lower the operating temperature.

(5) Roller wire etch depth is not suitable.

Should be re-plate.