Rub, fold, and abrasion resistance testing of digitally printed documents

The life cycle of commercially printed digital documents (in particular, marketing and promotional items, direct mailers, business communications, and on-demand color books) was examined to find stress points where potential permanence problems could exist. The stress and life cycle overview covers the stages of processes in printing and finishing, mailing preparation and fulfillment, distribution, usage, and recycling. Stress points found in the different stages of the life cycle, whether physical or chemical, include (but are not limited to) scratching, rubbing, cracking, solvent exposure, light exposure, moisture exposure, heat exposure, and air contamination exposure. Tests for abrasion resistance, folding resistance, solvent resistance, light-fastness, water-fastness, thermostability, and gas/ozone fastness were researched. Based on a survey given to randomly selected printers, printing press vendors, and print buyers, the tests for abrasion resistance, folding resistance, and rub resistance were selected. Using offset lithography as a benchmark, three commercial digital presses as well as high-speed ink jet technology were included in this testing. Using a combination of solid circular test targets and the “Three Musicians” test target (an image for visual comparisons), the Taber Abraser testing method, the Sutherland Rub testing method, and a folding procedure outlined in ASTM document F 1351 were used to examine and to compare the five presses in this study (three commercial digital presses, one offset lithographic press, and one high-speed ink jet press). After testing was performed, visual ranking, changes in density, Delta E, and the abrasion resistance index were used as the criteria to evaluate results. Testing results showed that the high-speed ink jet held up the best in each test performed during this research; however, the image quality of the high-speed ink jet press was less than the image quality of any other press in this study. The second best performer in the testing was the offset lithographic press. The test performance of these particular presses, as compared with the commercial digital presses, was attributed to the different drying methods in each of the different printing technologies. In the ink jet and lithographic presses, the evaporation, absorption, and oxidation drying methods seemed to hold up better to the testing performed than the drying method of toner-based technology. With oxidation and evaporation, the image (i.e., the ink) actually becomes a part of the paper after drying, whereas, in toner technology, the image (i.e., the toner) is fused to the paper and actually sits on top of it. Within the digital printing industry, coatings have been put in place to alleviate some of these problems, but they have not been tested here. This research shows that offset lithography is the dominant technology in terms of offering abrasion and folding resistance of its printed product

Permanence of toner on paper-Based on the life cycle of documents

This study outlines the life cycle of digitally printed marketing and promotional materials, transactional and business communications, direct mail, and on-demand color books. For each of the stages of the life cycle, stresses that influence permanence are discussed. A methodology is laid out to test the key variables determining the life expectancy of digitally printed products