Formulation, characterisation and flexographic printing of novel Boger fluids to assess the effects of ink elasticity on print uniformity

Model elastic inks were formulated, rheologically characterised in shear and extension, and printed via flexography to assess the impact of ink elasticity on print uniformity. Flexography is a roll-to-roll printing process with great potential in the mass production of printed electronics for which understanding layer uniformity and the influence of rheology is of critical importance. A new set of flexo-printable Boger fluids was formulated by blending polyvinyl alcohol and high molecular weight polyacrylamide to provide inks of varying elasticity. During print trials, the phenomenon of viscous fingering was observed in all prints, with those of the Newtonian ink exhibiting a continuous striping in the printing direction. Increasing elasticity significantly influenced this continuity, disrupting it and leading to a quantifiable decrease in the overall relative size of the printed finger features. As such, ink elasticity was seen to have a profound effect on flexographic printing uniformity, showing the rheological tuning of inks may be a route to obtaining specific printed features

THE INVESTIGATION OF THE FOLDING QUALITY IN THE PRINTING HOUSE “BALTO“ / LANKSTYMO KOKYBĖS TYRIMAS UAB BALTO SPAUSTUVĖJE

In the paper the folding quality in the printing house “BALTO”is investigated. The concept of quality, paper folding process,combined folding machine parameters and printing papers aredescribed. In the paper the percent of folding defects is determined,the spoilage dependence on paper characteristics, foldingmachine settings and other factors are investigated. Resultswere presented as histograms and were analyzed using statisticalmethods

Investigation into the accuracy of colours reproduced by the ricoh printer / Spausdintuvo „Ricoh“ spalvų reprodukavimo tikslumo tyrimas

The paper investigates the reproduction accuracy of Ricoh Aficio colour 3006 printer. The study has been conducted analyzing four-color (CMYK) gradation curves – the compliance of zonal absorbance with standard references and printing stability of gradation scales. The obtained colours have been measured spectrophotometrically determining the coordinates of colours CIE L*a*b* and differences in colours ΔE. Eight printing regimes and their settings have been examined.  It has been found that the printer Ricoh has inaccurately colour grading. However, the quality of colour reproduction is sufficient for printing data not requiring high accuracy of colour reproduction. Colour grading significantly differs from the theoretical approaches, though some regimes (Gamma, Brightness, CMYK simulation) allows achieving theoretical values. Despite the high inaccuracy of gradation, differences in colour are not high enough due to corrections made by software. Santrauka Darbe tirtas spalvinio spausdintuvo ,,Ricoh Aficio 3006“ spalvų atgaminimo tikslumas. Tyrimas atliktas analizuojant keturių spalvų (CMYK) gradacines kreives – zoninių optinių tankių atitiktį etalonui ir gradacinių skalių spausdinimo stabilumą pagal zoninių optinių tankių verčių sklaidą. Spalvų iškraipymas tirtas spektrofotometriniu metodu nustatant spalvų CIE L*a*b* koordinates ir spalvų skirtumus ΔE lyginant su etalonu. Tyrimai atlikti esant 8 spausdinimo režimams ir keičiant tų režimų nustatymus. Nustatyta, kad spausdintuvas „Ricoh“ spalvas atkuria netiksliai, tačiau spalvų atgaminimo kokybė patenkinama, esant spalvų reprodukavimo aukštos kokybės nereika­laujantiems darbams. Spalvų gradacijos gerokai skiriasi nuo teorinių, bet kai kurie režimai („Gamma“, „Brightness“, „CMYK Simulation“) leidžia atspaudų gradacijas priartinti prie teorinių. Nepaisant didelių gradacinių skirtumų visų spalvų skir­tumas lyginant su teoriniu nėra didelis galimai dėl spausdintuvo programinio spalvų koregavimo. Raktiniai žodžiai: „Ricoh Afficio 3006“; spalvų gama; reprodukavimas; spalvų koordinatės; spektrometrija; spalvų skirtuma