Intaglio common fault - poor color accuracy

There are several reasons why plastic film registration is not allowed:

(1) Longitudinal direction (running direction) Printing register change

1 The tension changes when the film is pulled.

Cause: The reel brake of the uncoiling device is not properly prepared; the reel material is too much, or the diameter of the reel material is too large; the three roller speeds are set incorrectly: the surface friction of the three roller surfaces is reduced; the tension of the rewinding machine is changed.

Countermeasures: Check and adjust each control device.

2 The difference in the diameter of the plate cylinder is poor.

Cause: The growth of the diameter difference during the platemaking process is inaccurate.

Countermeasure: Measuring the diameter difference.

3 abnormal rules line.

Cause: Insufficient density, printing offset, etc.

Countermeasures: Adjust the sensitivity of photocells, and artificially eliminate defects such as plate stencils.

4 The diameter of the plate cylinder is small.

Reason: The smaller roller diameter overlay accuracy is difficult to control:

Countermeasures: If the length of the bag is short, the imposition method may be used, ie, two or more bags may be printed on one roller.

(2) The lateral register device is unstable.

Causes: 1 The film is loose on one side and the guide roller is in parallel.

2 printing pressure is not uniform;

3 Plate cylinder and impression cylinder form taper;

4 Film tension changes, etc., and the film swings left and right.

Countermeasures: Check and adjust each element one by one, such as when the lateral register device is loose.