(1) Causes and Solutions for Blocking Plates Caused by Imprinting of Ink in the Ink Receptacle of Gravure Plates Cause: The ink dries too quickly.
Solution: Reduce the amount of solvent to reduce the drying speed of the ink; or re-adjust the ink to slow-drying ink; or reduce the viscosity of the ink.
Reason two: The ink PH value is too low.
Solution: Check the pH of the ink and adjust the pH to a specified range.
Reason 3: The ink's fluidity is poor (high viscosity).
Solution: Because of the presence of air at the printing nip, this can be caused by installing a baffle or reducing air flow.
Reason 4: Poor printing conditions.
Solution:
(1) The drum is too hot: The heat of the discharge drum should be reduced and the drum should be cooled.
(2) Insufficient ink in ink fountain: Check the amount of ink in the ink fountain. If necessary, add new ink to the ink fountain.
(3) Printing speed is too slow: The printing speed should be increased.
(4) The squeegee blade is too sharp: The squeegee blade should be slightly flat.
(b) how to solve the dirty version?
The dirty version is a layer of resin (entrained pigment in the resin) that is also attached to the non-graphic part of the plate cylinder, and is transferred to the substrate, so that the printed material shows a sheet of dirt.
1. The main reasons for the dirty version are the following:
(1) The affinity of the resin to the chrome plating surface of the drum makes the squeegee not easy to clean the ink.
(2) The system composed of resin and organic solvent is in supersaturated state, and a large amount of resin precipitates and is not dissolved by the solvent.
(3) The ink is too wettable to the chrome-plated surface, or the solvent used in the ink is a slow-drying solvent.
2. Solution:
(1) Use solvents with strong dissolving power and fast evaporation.
(2) To control the viscosity of the ink, during the production process, the solvent should be used according to the actual situation, and added in time according to the loss of various solvents to maintain the stability of the ink viscosity.
(3) Frequently add fresh ink.