Abstract: An image-forming element for a printing apparatus which includes a support structure with a plurality of electrodes of a first type disposed thereon and an electronic control unit for energizing the electrodes. The image-forming element further includes a plurality of electrodes of a second type, each one of said electrodes of the second type being arranged for interacting capacitively through a dielectric layer with a number of electrodes of the first type, forming a group, the electronic control unit containing a first series of drivers for energizing the electrodes of the first type, each one of said drivers being suited for energizing one electrode of the first type within each group and a second series of drivers for energizing individually the electrodes of the second type, the first and second series of drivers being arranged such that the electrodes of the first type can be individually activated, image wise.

Abstract: An image-forming element including a cylinder having at its outer periphery a dielectric surface layer and, beneath the surface layer, a number of electrodes insulated from one another, the electrodes being connected to elements within the cylinder for selectively controlling the electrodes in accordance with an image pattern to be formed, this connection being established by securing in at least one opening in the wall of the cylinder control device which, on the one hand, are connected to electronic control components within the cylinder and, on the other hand, are connected to the electrodes on the periphery of the cylinder. An image-forming element thus prepared can be used in a printing device for reproducing information.

Abstract: A method of forming a multi-color image, comprising image elements in a first color which along at least part of their circumference adjoin image elements of one or more following colors wherein separation images in the first, second, third and any following color are each built up from image dot patterns of colored toner powder. The separation images are transferred to an intermediate support to collect said separate images to form a multi-color image. The multi-color image is then transferred from the intermediate support to an image receiving material. The second and each following generated separation image is generated so that the image elements, which on transfer onto the intermediate support are required to adjoin image elements of a separation image already transferred thereto previously, at least partially overlap said previously transferred image elements.

Abstract: A printing device for reproducing information having movable image-forming element with a dielectric surface. An image-forming station is provided in which a magnetic roller having a rotatable electrically conductive non-magnetic sleeve is disposed near the surface of the image-forming element. An electric field between the image-forming element and the magnetic roller is generated in accordance with an information pattern. An electrically conductive magnetically attractable toner powder is placed in the zone between the magnetic roller and the image-forming element during generating of the electric field. A magnetic field formed in the zone by stationary ferromagnetic knife blade disposed inside the magnetic roller sleeve and the blade is held between like poles of two magnets at an angle of between 70.degree. and 85.degree. to the tangential plane to the sleeve.

Abstract: An image-forming element for an electrostatic printer is provided with an endless support having thereon a dielectric surface layer and a number of image-forming electrodes beneath the surface of the dielectric layer. In the zone of the image-forming element that is used for image formation, the electrodes extend parallel to one another in the form of helix, having a pitch which is at least equal to the working width of the image-forming element so that each electrode appears only once in a line of the image. Each electrode is connected to a voltage means for supplying voltage to the electrodes. The voltage means is disposed on the surface of the endless support outside the zone used for image formation.

Abstract: A printing device for recording information in the form of toner images comprising a moveable image-forming medium on a support, the surface of which forms a dielectric layer; an image-forming station disposed along the trajectory of the image-forming medium having a magnetic roller with an electrically conductive nonmagnetic outer sleeve with magnets disposed inside the sleeve; a means for supplying electrically conductive toner particles to a linear zone in the image-forming station; and a plurality of electrodes for generating an electric field corresponding to a desired image pattern, said electrodes extending in the direction of movement of the image-forming medium and disposed so as to be insulated from one another and covered by a dielectric layer wherein each electrode can be actuated by a voltage source and each electrode can generate an electric field across the dielectric layer over part of the zone wherein image formation takes place when in the image-forming station.