Abstract: In a process for printing a halftone image a plurality of image data describing the halftone step of a halftone dot of a model image are taken over in processing frames. Color step values which determine color gradations of color dots and can be outputted optionally at print positions of a printing screen are obtained from the image data contained in the processing frames. To produce a reproduction image with a large number of halftone steps and, at the same time, a high local resolution in the region of contrast jumps of the model image, a color step value is obtained from each image datum by assigning a color step value existing in the reference pattern associated with the halftone step according to the halftone step described by the image datum and its position in the processing frame.

Abstract: Inking ribbon for thermographic printers that contains constituents that can be decomposed thermally or by radiation, particularly constituents that decompose upon release of a gas. Given correspondingly manufactured inking ribbons, the color-transferring regions (decomposition regions) can be more sharply defined, the required heating capacity for printing can be reduced and a better color adhesion on paper is achieved.

Abstract: An apparatus for microline-by-microline illumination and scanning of a planar original has a number of spaced illumination elements, each having longitudinal and transverse dimensions substantially corresponding to a microline, and a number of spaced light-receiving elements disposed perpendicularly with respect to the microlines and corresponding to the number of desired picture elements along a microline to be scanned. Each light-receiving element at least partially overlaps a microline. The illumination elements and the light-receiving elements are respectively disposed in parallel planes in a common film. Structure is also provided at each overlap of a light-receiving element with a microline for coupling light from an illuminated microline to the light-receiving element.

Abstract: An improved inking ribbon for color transfer under the influence of heat comprises the ribbon having a carrier layer and a colored layer with the heat-soluble release layer interposed therebetween, which release layer is composed of a sublimable material to avoid renewed adhesion of the released portion of the color layer to the inking ribbon after a color transfer to the printing medium has occured.

Abstract: A method for manufacturing a flat illumination unit provides light guide channels in the form of transparent rods arranged in lines on the upper side of a plate. The upper side of a plate is coated with a casting compound and, after hardening of the casting compound, the plate is eroded from the opposite side until only the light guide channels remain respectively surrounded on three sides by the casting compound and therewith form a film.