Research of Elastic Parameters of Paper and Prints

Knowledge of the elastic properties of prints during printing processes is essential in printing presses. A computational inverse technique is presented to determine the elastic properties of materials. An effective technique for identification of elastic properties of prints consisting of the paper and several layers of ink and varnish is based on experimental data of modal vibration testing and finite element modelling. The aim of finite element modelling and optimization is to guess the material properties obtaining the same vibration frequencies and modes while test specimen is loaded in the same way as on printing press. Proposed technique can be used for the printing process modelling as non-destructive method during the initial design stage

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

New reactive hole-transporting hydrazone and its adducts with diol and dithiol

New hole-transporting hydrazone with reactive vinyloxyethyl group and its glass forming adducts with 9-ethyl-3,6dihydroxymethylcarbazole and 4,4'-thiobisbenzenethiol have been synthesized. The thermal stability of the synthesized compounds has been estimated and their optical, photophysical and photoelectrical properties have been studied. The ionisation potential of 5.14 eV has been established for 2-vinyloxyethyloxy-4-diethylaminophenyl-1-carbaldehyde N,Ndipheny1hydrazone by electron photoemission technique. Hole mobilities exceeding 10(-5) cm/(V-s) at high electric fields have been observed by the time of flight technique in the 50 % solid solution of the hydrazone in bisphenol Z polycarbonateVytauto Didžiojo universitetasŽemės ūkio akademij

INVESTIGATION INTO THE FRICTION AND ROUGHNESS PROPERTIES OF PRINTS USING CONVENTIONAL AND UV INKS / UV IR ĮPRASTAIS DAŽAIS SPAUSDINTŲ ATSPAUDŲ ŠIURKŠTUMO IR TRINTIES SAVYBIŲ TYRIMAS

The article experimentally investigates the properties of offset print friction and determines static and kinetic coeffi­cients of friction. Conventional and UV inks have been found to increase the static friction coefficient and re­duce the kinetic friction coefficient between paper and print. The roughness pro­perties of two different types of paper and prints using conventional and UV inks have been examined and compared thus determining that conventional inks strongly increase the roughness of print surface and that the influence of UV inks depend on the type of paper. Santrauka Nagrinėjamos popieriaus ofsetinių atspaudų trinties savybės ir nustatyti statinis bei kinetinis trinties koeficientai. Nustatyta, kad įprastiniai ir UV dažai didina atspaudo į popierių statitinio trinties koeficiento dydį ir mažina kinetinio koeficiento dydį. Atliktas dviejų rūšių popieriaus su įprastais ir UV dažais šiurkštumo palyginamasis tyrimas ir nustatyta, kad įprasti dažai atspaudų paviršiaus šiukštumą stipriai didina, o UV dažų poveikis priklauso nuo popieriaus rūšies. Reikšminiai žodžiai: atspaudai; įprasti dažai; popierius; šiurkštumas; trintis; UV dažai

Synthesis, photophysical and photoelectrical properties of glass-forming phenothiazinyl- and carbazolyl-substituted ethylenes

Phenothiazinyl- and carbazolyl-substituted ethylenes have been synthesized and found to constitute electro-active materials with high thermal stability as characterised by thermo-gravimetric analysis. Steady state absorption and luminescence spectra of the synthesized derivatives were examined in detail revealing green-blue emission with efficiency ranging from 13 % to 28 %. Based on the emission spectra of the synthesized compounds Commission Internationale d’Eclairage (CIE) chromaticity coordinates have been obtained. Major luminescence decay time component of ~2.5 ns was determined in dilute solutions of the compounds, whereas significantly shorter one has been estimated in thin films. Electron photoemission spectra of the materials have been recorded and the ionisation potentials of 5.3-5.4 eV have been established. Room temperature hole drift mobilities of the diarylethylenes dispersed in polymeric host approached 10-5 cm2/Vs at high electric fields