Analysis and troubleshooting of the most popular i

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Analysis and troubleshooting of ink printing

1 The main reasons for the collapse of graphics and texts are:

1) caused by the printing process itself

2) excessive printing pressure

3) the ink viscosity is too high

4) uneven mixing of ink

remedial measures:

1) pad the plate and adjust the height balance of printing

2) adjust the printing pressure

3) adjust the ink viscosity or use low viscosity ink

4) stir ink reasonably

2. The main reasons for blurred graphics and texts are:

1) plate making problems and poor quality of printing plates

2) high ink viscosity

3) poor dispersion of ink and pigment

4) the contact between the printing plate and the ink roller is too tight

remedial measures:

1) the printing plate should be flat and bright

2) adjust the ink viscosity and control it at 25 ~ 35s/4 cups

3) fully stir the ink

4) adjust the printing pressure

3. Insufficient ink transfer

main reasons:

1) insufficient printing pressure

2) the hardness of the flexo is not enough or the wrinkle roll is blocked; Intaglio text hole is too deep

3) the water content of the paper is too large

4) ink roller wear and aging

5) poor ink fluidity

remedial measures:

1) increase the printing pressure

2) check whether the hardness of the flexible relief plate is within the range of sh42 ± 3, replace the flexible plate with good elasticity or eliminate wrinkles; Clean the blockage in the roller and gravure, and replace the gravure (the engraving depth is required to be 25 ~ 45 μ m)。

3) use ink with strong hydrophobicity

4) clean the dried ink spots on the printing plate and pay attention to the surface treatment of gravure rust

4. Poor ink film resistance

main reasons:

1) the resistance of ink itself, such as poor water resistance and light resistance

2) poor quality or insufficient content of film-forming resin in ink

remedial measures:

1) replace new ink or add resin solution (pH value is controlled between 8 and 9.3)

2) replace the light resistant ink or add ultraviolet absorbent to the ink

3) add an appropriate amount of ink (such as acrylic acid or calcium salt)

5. Ink film has pinholes

main reasons:

a. (5) uncover the chemical pinholes on the iron door of the hydraulic control box, which are characterized by different pinhole positions, sizes and quantities

1) insufficient or excessive defoamer

2) excessive dilution of ink

3) too much ink with low viscosity

b. mechanical pinholes, characterized by pinholes often appear in the same part, and pinholes of the same size and number appear repeatedly

1) rough layout

2) the inking roller is defective or not concentric

remedial measures:

a. chemical pinhole:

1) add an appropriate amount of defoamer

2) add the original ink

b. mechanical pinhole:

1) the printing unit runs in a section or changes the printing plate

2) correction, such as data inking roller and adjustment of printing pressure

6. Ink foaming

main reasons:

1) the amount of defoamer added is insufficient or excessive

2) excessive dilution of ink

3) too many low viscosity inks; Defoamer has quality problems; The circulation of ink is insufficient or the ink delivery pipe leaks

remedial measures:

1) defoamer should be controlled at about 0.2%

2) increase the circulation of ink

3) replace the pipe or repair the damaged part

it is best to store the ink for 48 hours before using it on the machine (after its foam disappears and stabilizes)

7. Ink gelation

main reasons:

1) using the wrong solvent

2) mixed with inks of different properties

3) poor storage environment

4) the ink deteriorates over time

remedial measures:

1) use solvent with good solubility, and add an appropriate amount of cosolvent to create a closed loop of the industrial chain (ethylene glycol, glycol ether)

2) select the ink with the same performance and brand to mix the spot color ink

3) measure accurately when adjusting ink

4) the ink should be sealed at any time after use and stored in a ventilated and dry place

5) change the ink (add TM-3 or inorganic salt demulsifier into the ink)

8. Printing plate wear

main reasons:

1) roller contact is too tight

2) the ink is mixed with coarse and hard particles to avoid energy consumption

3) paper scraps or dust enter the ink or ink bucket

4) excessive printing pressure

5) poor printing plate quality

remedial measures:

1) readjust the contact clearance of the drum

2) filter ink

3) clean the ink fountain regularly

4) adjust the printing pressure

5) replace the printing plate

printing technology

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