| Author(s) | Collection number | Pages | Download abstract | Download full text |
|---|---|---|---|---|
| Чубак Є., Uhryn Ya. M. | № 2 (86) | 91-101 |
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The development of the packaging industry encourages product manufacturers to search for ways to improve its quality. Printing enterprises intensively use gravure printing to decorate packaging. The modern market of printing presses is very diverse. Therefore, the choice of one or another equipment is influenced by many factors. Among them are the number of colours of imprints, the type of printed material, its dimensions (sheets, rolls), print volume, etc. One of the quality assurance problems is maintaining the balance of the interaction of the structural units of the printing press, in particular, the inking and printing units.
The article is devoted to the morphological analysis of the structure of the printing and inking systems of web-fed gravure press, which are used for printing packaging materials. Varieties of impression cylinders of web-fed gravure press are considered, and the classification of inking units is presented. It is studied that the construction of the impression cylinder significantly affects the deformation of its coating during printing. The method of calculating pressure during printing is described. It is confirmed that with constant deformation of the coating of the impression cylinder, the internal tension decreases and a relaxation phenomenon is observed, which leads to a gradual decrease in pressure in the printing zone. The larger the width of the gravure press is, the more pressure must be applied to obtain the required width of the printing zone. Significant pressure on the edges of a large-diameter cylinder causes its uneven pressure distribution in the printing zone. This causes variation in image quality across the print width and creates problems when passing the roll web, and affects the accuracy of colour matching on the imprint.
Modern gravure presses have a special design of impression cylinders, in which the flexible shell of the coating rotates around the rod and adapts to the deformation of the cylinder. Thanks to this, the same pressure is achieved along the entire length of the plate cylinder, which can be adjusted. Some structural solutions have gravure presses that contain pairs of cylinders: a steel cylinder with an elastomeric coating (with a smaller diameter) and a chrome-plated steel cylinder, which allows for obtaining a narrow printing area. After all, the smaller the width of the zone, the clearer and better the quality of the printing. The impression cylinder can be coated with different degrees of hardness, which ensures the stability of printing on webs with a large width. The most common solution for solving print quality problems is the use of cylinders with an adjustable form of their coating.
Keywords: morphological analysis, structure, printing and inking system, deformations, gravure printing, imprints, packaging, quality.
doi: 10.32403/0554-4866-2023-2-86-91-101
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