Influence of material smoothness on the printing quality of color labels

The smoothness of the material is an important indicator to ensure the printing quality, especially in the case of halftone color printing. In label printing, some layouts have long patterns and large contrasts, and they have requirements for highlights and dark tones. Therefore, materials with poor smoothness often have problems. To ensure the quality of labels, you must use high-smooth materials or patterns. Pre-press processing, such as adding spot colors, shortening tone, etc.

For self-adhesive materials, there are several reasons that affect the surface smoothness of the material:

(1) The smoothness of the face material; the most important index is the key factor that affects the smoothness of the overall material.

(2) The flatness of the bottom paper; the bottom paper is equivalent to a mold, the bottom paper is not good, the composite material must be uneven, and the shape is similar to the bottom paper.

(3) The uniformity of the glue, whether it is direct coating or indirect coating when making the adhesive, the glue layer must be uniform, otherwise problems will occur, such as uneven pressure during printing, and flowering of graphics and text.

Test method one: comparison method

Print three materials at the same time without changing any conditions of the equipment

(1) The coated paper material complained of

(2) Material that the printing house considers to be qualified coated paper

(3) Mirror coated paper material provided by the supplier (the purpose of using this material is; the surface smoothness of the mirrored paper is better than that of coated paper, and complaints about the printing quality of coated paper can be found from the comparison of the smoothness)

Test method two: elimination method

In order to eliminate white spots caused by printing plates or inks, the elimination method is used for testing. After the equipment is adjusted, first use the materials complained by the printing plant to print full-color samples (finished labels), and then print black, magenta and blue monochrome samples respectively.

solution:

-Contact the supplier and ask the supplier to provide similar materials with high smoothness.

-Change printing materials; change from coated paper to mirror-coated paper with high smoothness.

-Change the color structure of the label, overprint from dots, and convert to spot color printing. Spot color printing can control the thickness and pressure of ink and improve the printing effect of problematic materials.

-The label is changed from single-sheet printing to rotary printing, which can be printed in multiple colors to improve the printing effect of problematic materials.