Causes and countermeasures Of Gravure printing failure of eight kinds of common Round Boxes Of Chocolates

Causes and countermeasures Of Gravure printing failure of eight kinds of common Round Boxes Of Chocolates

 

This paper comprehensively sorts out the causes and countermeasures of eight common faults in the process of film gravage printing, so as to facilitate everyone to check when they encounter problems.

 

1, color is not accurate

 

(1) The tension of the film changes, so that the longitudinal printing color change.

Each tension control device should be adjusted, such as adjusting the reel brake of the unwinding device; Reasonable setting of roller speed; Improve the roller surface friction; Adjust the coiling tension of the rewinder.

 

(2) There is a diameter difference in the printing drum. The diameter of the first, second and third color printing plate drum is thickened or reduced in turn, which causes the change of longitudinal printing color.

 

A new plate should be made.

 

(3) regular line density is insufficient, printing color longitudinal offset.

The sensitivity of photocell should be adjusted and the pasting fault of printing plate should be eliminated.

 

(4) The guide roller is not parallel, the printing pressure is not balanced and the taper of the plate drum and the printing press drum, resulting in lateral swing of the film, unilateral relaxation, and lateral color instability.

Targeted adjustments should be made.

 

(5) the adjustment screw at the shaft end of the printing plate drum is loose, causing instability in lateral color registration.

The tightness of the screw should be readjusted.

 

(6) If the contact pressure of the rubber roller and the flower roller is too large, the printing pattern will produce double patterns.

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

 

2. There are spots on the printing surface

 

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

The viscosity of the ink should be adjusted appropriately to make the viscosity of the ink moderate and good fluidity.

 

(2) the plate depth is too deep or the scraper Angle adjustment is improper.

The Angle of the scraper should be adjusted appropriately, or the plate should be re-made.

 

(3) Improper control of printing pressure.

It should be adjusted appropriately.

 

(4) Too much static electricity on the surface of the printed matter.

Static electricity should be eliminated.

 

(5) poor drying ink.

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

 

3, the printing surface foaming

(1) If the ink surface has crusted, and the internal ink is not dry, once it breaks through the crust, it will form a volcanic spout like bubble hole, which is mainly caused by rapid drying.

 

Should adopt low temperature - high temperature - low temperature drying process route, and try to use slow drying ink.

 

(2) During the printing process, a large number of bubbles will be generated in the ink bucket, and the bubbles will adhere to the printing roller, so that the dot of the printing pattern will disappear locally or stain the pattern.

 

Should make the ink to maintain appropriate viscosity, to minimize the ink drop, and the use of circulating pump to prevent bubbles into the ink.

 

4, the printing surface has pear skin pattern

If overprinting on a dry printing surface, the base color ink is dissolved and partially mixed with the second color ink, the printing surface will produce pear skin patterns.

 

One is to adjust the ink viscosity; The second is the correct control of drying speed; Three is reasonable to determine the depth of the version.

 

5, ink absorption is poor

When the product film surface multi-color printing, printing a second color of ink on a color film, if the absorption is poor, it will make the ink after the transfer of the dot into an independent state, forming a dot color is darker, other parts of the color is lighter uneven phenomenon. This has nothing to do with the amount of ink transfer or inconsistency and other issues, mainly with the diffusion of dot ink after transfer.

 

In this regard, one is the use of hysteresis solvent in the second color ink; Two is to try to make the second color ink scraper position to move close to the printing direction; Three is the second color after the ink should be as light as possible; Four is appropriate to deepen the second color version depth; Five is the use of reducing agent in the base color ink; Six is appropriate to improve the printing speed.

 

6, printing roll wear too fast

(1) The scraper is too thick.

Thinner blades should be used instead.

 

(2) scraper and printing roller contact pressure is too large.

The contact pressure of the two should be adjusted appropriately.

 

7, blade wear too fast

(1) The blade is too thin.

Thicker blades should be used instead.

 

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

The contact pressure of the two should be adjusted appropriately.

 

8, the version of the network blockage

(1) In the printing process, with a large amount of solvent volatilization, the viscosity of the ink increases, resulting in the drying up and blockage of the ink inside the wire.

Dry ink should be removed regularly.

 

(2) when the position of the scraper is far from the printing roller, the diameter of the roller or the depth of the roller into the ink tank is not enough, the hot air blown from the machine affects the ink on the surface of the roller, which is easy to cause serious blocking.

Targeted adjustments should be made.

 

(3) ink mixed with impurities caused by blocking version.

Impurities should be removed and ink filtered.

 

(4) In the printing process, the operation temperature is too high, resulting in the plate roller wire solvent evaporation speed is too fast, resulting in the plate network blockage.

Efforts should be made to reduce the operating temperature.

 

(5) The etching depth of the roller wire is not suitable.

A new plate should be made.