I. Ink blocked and delayed phenomenon: Ink printing quality on the substrate is poor because of ink fluidity. The ink roller cannot completely transfer ink and gradually become shallow.
- Problem 1: Ink thread head is too short and lacks liquidity
Analysis of specific problems: too much colloidal oil in the binders, too little liquid oil, too much filler resulting in poor liquidity.
Resolution: add inking oil to increase ink mobility.
- Problem 2: ink has a tactile feeling. It will be coagulated if doesn't stir.
Analysis of specific problems: ink mixing by the role of shear stress, ink flow, and shear stress is proportional to the size, no external force will be poor ink condensation flow.
Solution: check the mixing, so that the ink in the ink tank maintains the flow.
II. The drying speed of the ink is too slow: the ordinary 4-color ink does not dry 4-8 hours after printing, and it is easy to erase the picture and text.
Problem 1: the desiccant content of the ink is insufficient.
Specific problem analysis: can not play the role of catalysis, oxidation drying speed is not fast enough.
Solution: add an appropriate amount of desiccant.
- Problem 2: there are too many antioxidants in the ink.
Specific problem analysis: prevent the oxidation drying speed of the ink.
Solution: add an appropriate amount of desiccant and use a binder with good drying performance.
- Problem 3: ink contains too much non-dry oil or compound
Analysis of specific problems: the oxidation rate of non-dry oil or compound is slow, and the drying rate is slow.
Solution: adjust the ink formula or add desiccant.
III. The pulverization of the ink: the ink has been dried, but it is easy to turn into powder and fall off as soon as it is rubbed.
- Problem 1 : there is not enough adhesive in the ink.
Analysis of specific problems: the amount of binder is insufficient and the content of the pigment is too much. After drying, most of the binder is absorbed and can not form an oxidation protective layer on the surface of the pigment.
Solution: increase the proportion of binder, reduce the ink concentration, use fast-drying ink, and form a protective layer on the pigment surface after drying.
- Problem 2: the viscosity of the ink is low.
Analysis of specific problems: the adhesion of the ink on the paper is too small, the pigment in the ink is easy to fall off.
Solution: switch to high viscous ink to increase the adhesion to the paper.
- Problem 3: the absorbency of the paper is too good.
Analysis of specific problems: too much binder is absorbed by the paper and can not form a protective layer on the surface of the pigment.
Solution: switch to paper with relatively weak absorption or use fast-drying ink, so that the binder will not be over-absorbed by the paper.
- Problem 4: the drying speed of the ink is too slow.
Analysis of specific problems: the conjunctiva on the surface of the ink layer is slow, and too much binder can not be absorbed to form a protective layer on the surface of the pigment. Solution: add the appropriate amount of desiccant to speed up the drying speed.
- Problem 5: excessive emulsification
Analysis of specific problems: the ink contains too much water, the proportion of binders is reduced, the ink is destroyed, the viscosity is low, and the adhesion is small.
Solution: control the balance of water and ink to prevent excessive emulsification