Methods for Dealing with Common Embossing Problems

Common knife lines in gravure printing can cause linear defects, mesh defects, wrinkling and folding of the paper, and wrinkles. This article provides specific reasons and solutions for these issues for reference.

Knife lines causing linear defects in the printing area

Reasons:

• Scratches on the gravure cylinder

• Scratches on the doctor blade

• Micro-dust particles adhered to the doctor blade

• Protrusions on the printing cylinder or aluminum plating surface

Solutions:

• Reshaping or remaking the printing cylinder

• Replace the doctor blade

• Filter the ink and increase the ink wiping pressure

• Remove these parts from the gravure cylinder surface or reshape the printing cylinder

Mesh defects in printing

Reasons:

• High ink viscosity

• Ink drying too fast

• Doctor blade angle too sharp

Solutions:

• Reduce ink viscosity

• Use slower drying ink, but be careful to prevent mesh coverage

• Flatten the doctor blade angle

Wrinkling, folding, and wrinkles of the paper

Reasons:

• Paper edge relaxation

• Central part of the paper loosened

• Improper tension or the substrate material itself has wrinkles

• Excessive angle of substrate material wrapping on the rubber roller

• Excessive nip pressure

• Insufficient rubber hardness

• Improper machine layout

Solutions:

• Use an eccentric roller. If the machine does not have an eccentric roller, use plastic tape to wrap one end of the roller to compensate

• Use a bow roller or tension adjustment roller

• Use a tension adjustment roller

• Adjust the angle of paper wrapping on the roll

• Reduce nip pressure

• Use a high hardness rubber roller

• Study the roller assembly position