Adjustment and control points in the printing process

The printing process is a dynamic process. Due to various factors, print quality problems often occur. In this case, specific analysis should be carried out and corresponding measures taken to eliminate various kinds. Printing failure. Where should this work be from? It can be considered that the vast majority of failures (above 80%) are related to the following ten key points. Starting from the phenomenon of failure, it is possible to analyze which condition it belongs to and take corresponding measures to accelerate the troubleshooting process.

I. Changes in work pressure

Different printing conditions should have working pressures that are compatible with their printing conditions. In the process of printing pictures, ink pressure λ, inking pressure λ, and printing pressure λ should be adjusted frequently.

2. Tape tension changes

Changes in tape tension directly affect the accuracy of registration. If the registration accuracy is higher, the tape tension should be increased accordingly. However, the tension of the tape cannot be arbitrarily increased. If the tension of the tape is too large, the stretching and deformation of the tape will be exacerbated, which will become one of the main factors that affect the accuracy of registration.

3. Machine accuracy changes

Changes in machine accuracy mainly include the following parts.

(1) The accuracy of the printing cylinder and the impression cylinder.

The concentricity of roller journal and cylinder body ≤ 0.01mm;

The degree of parallelism between the plate cylinder and the impression cylinder;

The change of the center distance of the two rollers.

(2) The accuracy of the anilox roller

A. The accuracy of the anilox roll itself changes

Deep changes in cyberspace. The depth of the network hole is generally 0.023~0.03mm. If the network hole is improperly cleaned or the surface wear is increased, the depth of the network hole will be reduced, resulting in insufficient ink transfer amount.

Changes in the number of reticulate lines. Changes in the printing conditions should be adjusted accordingly.

The change of the cell's roughness. When the cell site is not properly processed, the surface of the cell surface is rough, or when the surface of the cell surface in the printing is eroded by the solvent to cause roughening of the surface, the ink transfer effect will be affected.

B. Changes in the positional accuracy of the anilox roll and the printing plate cylinder and the ink fountain roller. It mainly includes changes in center distance and changes in parallelism.

(3) The accuracy of the ink fountain roller changes.

Roller body surface quality changes: scratches or threads on the surface;

Changes in position accuracy with the anilox roll: parallelism and center distance.

(4) Change of transmission gear

Change in gear machining accuracy;

The surface of the tooth surface changes.

4. Registration accuracy changes

Changes in the positional accuracy of the printing plate cylinders;

Changes in the accuracy of printing materials;

Changes in the tension of printed substrates.