Research of the Influence of Digital Printing on the Optical Indicators of Imprints of Philatelic Products ‘On Demаnd’

One of the types of accidental products is marked and philatelic products. The ‘Own label’ service from Ukrposhta has gained popularity in Ukraine. This is an opportunity to make a stamp sheet, envelope or postcard with your own design. Shipments of such products, as a rule, are single or have a small shipment. Thus, there is a need to determine the optimal method of digital printing, which can effectively ensure the production of personalized branded products. Stamp sheets offered by ‘Ukrposhta’ were chosen for the research. Material — chalked gummed stamp paper weighing 102 g/m2, format 220×154 mm. A test form was developed that will take into account all the features of layouts that are inherent in branded products. The test form was developed based on the requirements of the standard and quality indicators defined for the evaluation of imprints obtained by the digital printing method. For printing imprints, equipment of various printing technologies was chosen: laser, jet, UV jet. Imprint processing was performed using a Levenhuk DTX 90 microscope, measurements on small areas — Sigeta Biogenic lite 40x-1000x LED Bino. An X-Rite SpectroEye spectrophotometer was used to analyze the color and gradation characteristics of the imprints. All measurements of color indicators were performed taking into account the color of the paper. A visual analysis of imprints obtained on all types of equipment was carried out. On sheets of branded paper printed on the Epson Artisan 1430 printer, the ink is smeared, the colors are desaturated, and the reverse text is not reproduced. Therefore, these samples were not taken into account during further measurements and analysis. When analyzing the imprints printed on the Mimaki UJF-3042FX, clearly defined horizontal stripes were found, which are visible to the naked eye and spoil the overall appearance. Therefore, it can be concluded that jet printing technology and UV printing are not suitable for forming images on stamp paper. Summarizing the results of the study of the color characteristics of the imprints, namely: brightness index, color difference and color tone, it can be concluded that all the studied imprints have flaws in one or another area. Black color is reproduced slightly lighter on all paper samples. On the imprints obtained on the Konica Minolta bizhub c224e, the color difference indicators are higher compared to the Xerox Versant 180 Press. The researched imprints on stamp paper obtained on the Xerox Versant 180 Press are reproduced most closely to the reference values of the control fields. Based on the results of the research, it can be concluded that the researched gummed stamp’ paper is quite suitable for the execution of individual orders by the electrographic printing method.