Assessment of the Condition of Anilox Rollers

To produce high-quality prints using flexographic printing technology, it is important, among other factors, how accurately and consistently the ink is delivered to the printing plate, and, from there, onto the printed material. This function is performed by anilox rollers. The aim of this research is to investigate the condition of anilox rollers in printing houses in the Baltic states. The study evaluated the wear and cell clogging of anilox rollers. The dependency of clogging on the cell size, as well as the dependency of wear on the cell size (i.e., change in cell volume) and quantity of doctor blades, was investigated. In addition, the uniformity of cell clogging and wear on the surface of the anilox roller was evaluated. Studies have shown that more than half of the anilox rollers in printing houses are not washed properly; higher line screen anilox rollers tend to become more clogged, and it is important to take measurements at more than three locations to assess the reliability of more worn rollers.

Correlation between Ink Thickness and "Shrink Sleeve" Flexographic Print Quality at a Stable Friction Coefficient

Flexographic technology usage is increasing in recent years. Predicted growth in the technology usage intensifies the demand for improved quality. It is expected that flexographic printing will achieve greater results than ever before. Since this technique is used in the printing of shrink sleeve packaging, it is imperative to meet the technical and economic requirements of the shrink sleeve product. This is primarily to ensure gliding of the white printing material. The amount of white should be as small as possible, making the sliding of the material optimal and the quality of the print better. Therefore, the quality of the printing was measured by changing the conditions of slippage and white color. This research has established a correlation between the thickness of the white layer and the reduction of print quality over thin lines.

Colorants in printing applications

This review article is a summary of the current knowledge in the field of colorants in printing applications. Printing inks belong as well as paints, coatings, plastics, and cosmetic formulations to the most important application systems for colorants, both for pigments and dyes. Colorants have to meet increasing demands in printing applications due to the considerable number of printing methods and consequently of a large number of specific printing formulations. Crucial factors besides the specific properties of a certain printing ink are the processing method and the required quality of the final printed product. Amongst the most important printing methods are letterpress printing, offset printing, flexographic printing, gravure printing, screen printing, and digital printing. Different processing methods are used for coloring of the individual printing inks. The coloring processes need to be coordinated in accordance with the steps of the printing processes leading to the final product.

Basics of flexography

The textbook deals with the theoretical and practical issues of flexographic printing technology. Much attention is paid to prepress and printing processes. Data on the adhesion of flexographic inks are presented, and theoretical and practical issues affecting the quality of printing are presented. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for teaching students of higher education institutions in the discipline " Flexographic printing technology "in the direction of bachelor's degree 29.03.03 and master's degree 29.04.03" Technology of printing and packaging production", can be used in practical work by specialists of printing enterprises and publishing organizations.

Crushing of Double-Walled Corrugated Board and Its Influence on the Load Capacity of Various Boxes

As long as the non-contact digital printing is not a common standard in the corrugated packaging industry, corrugated board crushing is a real issue that affects the load capacity of the boxes. Crushing mainly occurs during the converting of corrugated board (e.g. analog flexographic printing or laminating) and is a process that cannot be avoided. However, as show in this study, it can be controlled. In this work, extended laboratory tests were carried out on the crushing of double-walled corrugated board. The influence of fully controlled crushing (with a precision: ±10 μm) in the range from 10 to 70 % on different laboratory measurements was checked. Most of the typical mechanical tests were performed e.g. edge crush test, four-point bending test, shear stiffness test, torsional stiffness test, etc. on reference and crushed specimens. The residual thickness reduction of the crushed samples was also controlled. All empirical observations and performed measurements were the basis for building an analytical model of crushed corrugated board. The proven and verified model was then used to study the crushing effect of the selected corrugated board on the efficiency of simple packages with various dimensions.

Optimization of flexographic print properties on ecologically favorable paper substrates

Nowadays, the attention in many industries is shifting towards the problem of waste overproduction and production of the waste in general. This study aimed to find an alternative approach to the production of packaging which will be environmentally friendly and at the same time optimal in terms of the print quality. This was accomplished by using the minimal needed amount of material for the production of packaging and adjusting the parameters of the flexographic printing process to achieve the desired visual impression of the print. The designed motive for the packaging was printed on five different recycled papers, following the guidelines of sustainable design. Printing was performed on each recycled paper with different printing pressures (50N, 150N, and 400N). Smoothness was measured on each paper; and for every printed sample, colorimetric measurements and thickness of the lines in positive and negative were measured. Print contrast for each print was calculated, and microscopy of fine printed elements was performed. All chosen papers except one had average smoothnes of up to 3.2 s (the smoothest paper had the average smootheness value of 54.72 s). Smoothness results influenced the printed line widths. Specifically, when increasing the printing pressure, a significant deformation of the line width has occured on all papers except the smoothest one (deformations of the lines printed in positive were up to 400 μm for rough papers compared to maximum of 60 μm for lines printed on the smoother paper). Similar results were obtained for the lines printed in negative. Furthermore, legibility of the printed typographic elements of 4pt size was significantly influenced by the smoothness of the paper. Elements printed on the smoothest paper have displayed the negligible deformations when changing the printing pressure. For other papers, elements in positive were optimally printed by 50 N pressure, and elements in negative by the pressure of 400 N. The results of this research have enabled the optimization of the flexographic printing process when using each of the five types of recycled papers. Furthermore, the presented qualitative and colorimetric parameters of the prints enabled the assessment of the applicability of used papers as printing substrates for ecologically favorable packaging.