Printing Paper and Printing Quality--Common Paper Diseases (4)

※folds and creases

1) Crease: Refers to folds or overlaps in paper sheets to form moiré or creases. Can be divided into dead and sub-folding two.

2) Warping and arching: Warpage refers to the state where the paper is curled on both sides or corners, and the middle is concave; the arching refers to a state in which a large area in the middle or in the middle of the paper is arched, and two sides or four corners are concave.

3) Bubbling and bubble sands: Partial shrinkage of the blistering finger sheet, resulting in protruding foam on the paper surface, and fine wrinkling on the paper surface around the bubble; bubble sand is an arrangement of the paper surface A dense, fine bubble point.

4) Various wrinkles: According to the size and shape of the wrinkles, fine oblique wrinkles, curly wrinkles and so on.