engleski

Study of Electrophotography with luquide toner (Electroink)

Technically, the indirect electrophotographic printing is a very complicated job. It implements, 6 separate phases performed synchronically. They are charging, exposing, developing, the first transfer, the second transfer and cleaning. The influence of each phase on the quality of the multicolour reproduction has been researched in this work and the parameters which are not the standard ones for the production printing were used in it. The influence results of particular phases of electrophotographic printing process on the final reproduction have been presented in the gamut form (construction defined by ECI form of 378 patches). In investigation of the electrophotographic process, one substrates was used: Simbol (glossy fine art paper for printing in classical offset). In the starting phase, the influence of scorotron on the formation of the future free surfaces has been researched. The changes in gamut which appeared, were minimal ones (ΔVsimb=13, 3). The valid rule in this case is: the less scorotron voltage, the greater gamut volume. By increasing the laser strength, full tones do not change considerably, (ΔVsimb=10, 3 space unit). The developing process (developing drum and the squeegee rollers) influence the maximal change of the gamut inking (ΔVsimb= 301, 5 ; ΔVsimb=210 space unit). By application of higher voltages, the greater application of the ink is achieved. The activity of the developing drum influences the greater change of the full tones. By the extreme increase of the voltage of the squeegee rollers, only smaller degradation of the gamut volume is achieved (ΔVsim=17, 2 space unit). During the transferring process, two parameters varied: the temperature of the offset cylinder and the voltage of the offset cylinder. The increase of temperature causes the increase of the ink viscosity, which increases the gamut volume (ΔVsim=44, 8 space unit). The higher voltage of the offset cylinder ensures the better transfer. The change in voltage of 200V will cause the gamut increase (ΔVsimb=37, 7 space unit). The concentration increase of the pigment results in darker impression. During the colour variations, the gamuts ware not expected to be great(ΔVsimb=60, 2)

Electrophotography; charging; exposing; developing; transfer; gamut reproduction

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