Abstract: The invention relates to a method and devices for cleaning the surfaces of applicator rollers, photoconductor drums, transfer belts, and photoconductor belts using magnetic roller systems. The invention also relates to methods and systems for cleaning magnetic rollers to whose surfaces toner particles adhere. In a first embodiment, a squeegee/scraper is disposed at a distance to the surface of the roller. In another embodiment, a magnetic stator configuration with two spaced apart magnetic elements is used whose poles have substantially the same active direction.

Abstract: A method for operating a printer or copier in which at least one optical or mechanical attribute of the printed image support to be printed is detected using a sensor (steps 102, 104, 110). At least one printing parameter is given according to the sensor output signals (steps 106, 108, 112). The printed image support is then printed while using the printing parameters detected in such a manner.

Abstract: In a method and device to control a print process in a printer or copier, with a character generator generating a latent print image and a latent toner marking on an intermediate carrier. An exposure energy per area unit for the generation of the latent toner marking is decreased in comparison to an energy per area unit for generation of the latent print image. The latent print image and the latent toner marking are inked with toner in the developer station. An optical reflection sensor determines color density of the ink toner marking. Toner concentration is adjusted in a developer station dependent on a signal of the reflection sensor.

Abstract: There is described an applicator element for providing a layer of a liquid ink, in particular for inking a latent image carrier of a device for electrographic printing or copying, the surface of the applicator element having a structure with a plurality of areas at which the detachment of droplets from the liquid layer is facilitated.

Abstract: A printer includes modular printing units held in receptacles, such as by a snap action retainer to permit easy removal and replacement. The printer units each include a photoconductor on which is produced a toner image and multiple printer units are provided in the printer. The photoconductor may either transfer the toner image of each printer unit to the final image carrier, or may transfer the toner image to an intermediate carrier which transfers the toner to the final image carrier. A transfer apparatus effects the transfer of the toner image from the photoconductor to final image carrier, or to the intermediate image carrier depending on the embodiment. The printer units may provide layered toner of different colors on a single side of the final image carrier and may provide two sided printing of the final image carrier. A single toner fixing unit is provided to fix the toner to the final image carrier.

Abstract: A device for electrographic printing or copying has an applicator element (26, 26a), which supports a layer (48, 72) of the ink. An air gap (L) is provided between the liquid layer (48, 72) and the surface of the latent image support (12), said surface being located opposite the liquid layer. In order to ink the latent image on the latent image support (12), droplets (50) are transferred from the liquid layer (48, 72) to the surface of the latent image support (12) while passing through the air gap (L). An alternating field of force (an electric or acoustic alternating field), which acts upon the liquid layer, is provided in the air gap.

Abstract: A device for cleaning an image carrier of residuals of an ink image, in which for inking the latent image on a latent image carrier, droplets are transferred from a liquid layer onto the surface of the latent image carrier by overcoming an air gap. The cleaning device is arranged at the circumference of the image carrier and removing the residual ink remaining after transfer of the image inked with a liquid ink is removed from the surface of the image carrier.

Abstract: There is described an applicator element for providing a layer of a liquid ink, in particular for inking a latent image carrier of a device for electrographic printing or copying, the surface of the applicator element (26) having a structure with a plurality of areas (78, 80, 86, 88), at which the detachment of droplets from the liquid layer is facilitated.

Abstract: A method for operating an electrographic printer or copier includes determining an adapted exposure energy before the start of the printing process. To this end, a portion of the image elements on a charged photoconductor region is exposed to a predetermined exposure energy. The other portion of the image elements on the photoconductor region is not exposed. A raster parameter which takes the ratio between exposed and unexposed image elements into account is used during the determination of the adapted exposure energy. A printer or copier apparatus for carrying out the method is also provided.

Abstract: A method in which a multilevel character generator (22) is adjusted using a single correction factor (KF) during an automatic compensation operation such that high-quality printed images can be obtained also in the instance of modified printing conditions.

Abstract: A multicolor printer uses toner of two polarities applied on a photo conductor layer prior to the two toners being applied to a carrier. The photo conductor layer is provided with an image-wise illumination with regions of different illumination to form regions of different potentials. The regions of different potentials are developed by applying the toner of two polarities. Further colors of toner may be used, provided illumination with corresponding different illumination and provided charging of the photo conductor layer to change relative potentials is performed. An overall illumination of the photo conductor layer between developing steps changes potential levels on regions not covered by toner but not in areas covered by toner.

Abstract: An electrophotographic printer includes a print unit with a photoconductor that receives a toner image and another printing unit to produce another toner image. The printer unit is removably fastenable in a receptacle in the printer, and other identically constructed printer units are also fastenable in receptacles in the printer.

Abstract: A method for multicolor electrophotographic printing includes a photoconductive layer system having surface elements or surface regions that are provided with an initial negative potential, then are exposed to varying degrees and developed with negatively charged toner particles of a color. A uniform light source is arranged closed to the photoconductive layer system and then the surface elements are developed with a second color toner. In particular, the image being printed has image elements of different colors which correspond to different surface elements of the photoconductor. These surface elements are differently illuminated to achieve different potentials and are developed by color particles by depositing the color particles on the respective surface elements. The charge potential of ones of the surface elements is increased and then surface elements not covered by color particles are illuminated to reduce the charge potential there prior to subsequent development of further surface elements.

Abstract: An electrophotographic color printer includes a photoconductor and a printing unit for producing a toner image on the photoconductor. The printing unit is removably provided in a receptacle in the printer.

Abstract: A printer or copier has a photoconductor on which charge patterns are formed that are in turn inked and printed onto a recording medium. An optimized exposure energy is determined for a given potential of the photoconductor by calculating a sensitivity factor. The optimized charge potential may also be calculated on the basis of the sensitivity factor for a given exposure energy.

Abstract: In an electrophotographic printing process as well as an electrophotographic printer for printing a substrate, a photo-sensitive layered system is brought to a homogeneous initial state by impressing an electrical field having a first direction. The photoconductive layer is exposed with predetermined image structures according to the image. The entire photoconductive layer is exposed uniformly through the cover layer and/or the electrode layer. Charged toner particles are applied to the cover layer in a development step. The toner image is then transferred to the substrate. If more than one copy is required, the development step and the transfer step are carried out a number of times, the electrical charge image present inside the layered system being retained. The substrate is conveyed at a very high speed by a conveyor device in this operational state.

Abstract: A printer or copier optimizes half tone printing by a method including printing a raster toner mark and scanning the raster toner mark to determine if it is in the parameters for optimum half-tone reproduction. The raster toner mark has pixels with toner and pixels without toner. If the optical density of the raster toner mark is below a lower limit, the bias voltage between the photoconductor and the developer station is increased so long as the current bias voltage is below an upper limit. The optical density may also be increased by increasing the ratio of toner mixed into the carrier particles. If the raster toner mark is above the target optical density, the bias voltage is decreased (if it is above a minimum level) and/or the ratio of toner to carrier particles is decreased. The combined effects of adjusting toner/carrier ratio (a slower process) with adjusting the bias voltage (a faster process) provides optimization of the half-tone printing.

Abstract: An electrophotographic process and arrangement for generates a macro-charge zone inkable by toner applicators and delimited by an inking limit (EG) having an adjustable contour on a photoconductor of a printing or copying machine, using at least one exposure-variable and position-variable controllable light source (LED), such as an LED comb or laser. By controlling the exposure of the light source and its radiation position on the photoconductor and by controlling a bias voltage (UB) which can be applied between photoconductor and toner applicator, an electrostatic potential relief (UR) made up of individual adjacent micro-charge zones (UM) of exposure-dependent size is generated on the photoconductor and the inking limit (EG) is defined, the contour of the inking limit being determined by the bias voltage level (UB) on the potential relief (UR).