Images rosette occurrence eradication on corrugated carton packages printed by flexographic post-printing

الملخص EN

Printing depends on halftoning to simulate shades of gray, color, and image detail.

In four color process printing, four halftones – one for each of the cyan, magenta, yellow, and black inks are overlaid to produce the image.

The problem is when overlapping two or more halftone grids can create an objectionable pattern called a rosette.

With using flexographic printing on corrugated board, it must use coarse screenings for printing because of the nature of corrugated board; the occurrence of rosette is growing increasingly with these coarse screenings.

The occurrence of rosette is one of the most important phenomena that affect the final appearance of an image and its details, which make it easy to distinguish rosette with the naked eye.

This research is interested in finding a new approach of processing in pre-press stage during the preparation of the digital file which eradicates the rosette formed during the printing using the potentials from processing software to control the screen dots diameter produced of three process colors (C, M, and Y) and uses the same screen angle.

With this approach the black color is eliminated and its compensation with C, M, Y colors accordingly saves fourth ink, reduces the printed layers and maintains the strength and hardness of corrugated board as well as provides significant economic value.