Abstract: A direct electrostatic printing method performed in consecutive print cycles in which control signal pulses are applied on the one hand between a toner particle source and a back electrode and, on the other hand, between the toner particle source and electrodes on a printhead structure interposed between the toner particle source and the back electrode. The pulses are so controlled as to be in accordance with an image configuration to generate a pattern of electrostatic fields which selectively permit or restrict the transport of charged toner particles from the particle source toward the back electrode via the printhead structure.

Abstract: The present invention relates to a direct electrostatic printing method, in which a stream of computer generated signals, defining an image information, are converted to a pattern of electrostatic fields which selectively permit or restrict the transport of charged toner particles from a particle source toward a back electrode and control the deposition of those charged toner particles in an image configuration onto an image receiving medium. Particularly, the present invention refers to a direct electrostatic printing method performed in consecutive print cycles, each of which includes at least one development period (t.sub.b) and at least one recovering period (t.sub.w) subsequent to each development period (t.sub.b), wherein the pattern of electrostatic fields is produced during at least a part of each development period (t.sub.

Abstract: In an image recording method, the toner particles are preferably obtained by microencapsulation techniques. The techniques form a dispersion of a core material in a medium containing the shell material. The shell material is deposited upon the surface of the core material to form the capsules. The capsules are hardened to prevent their agglomeration. The capsules are then recovered. Preferably, the continuous phase is normally a solution of the shell material. The core structure advantageously comprises a colorant and at least one additive, such as, for example, a resin binder.

Abstract: A direct electrostatic printing device and method for printing an image to an information carrier with increased density harmonization. By continuously keeping track of the amount of pigment particles each aperture has available and thereafter using this information and the desired print density to control the control electrodes of the individual apertures, a harmonization of the printed density from different apertures is attained.

Abstract: An image recording apparatus includes at least one print station and an image receiving medium caused to move in relation to the print station. The print station includes a particle source for delivering charged particles in a position adjacent to a printhead structure interposed between the particle source and the image receiving medium. The printhead structure has a first surface facing the particle source, a second surface facing the image receiving medium, and a plurality of apertures arranged through the printhead structure. Aperture controllers are arranged in conjunction with the apertures to modulate streams of charged particles from the particle source through the apertures toward the image receiving medium. Depression areas are arranged on the first surface of the printhead structure in such a configuration that each aperture is arranged in a depression area. The part of the aperture facing the particle source is sunken with respect to the first surface of the printhead structure.

Abstract: A direct electrostatic printing device and method for printing an image to an information carrier with improved harmonization of the printed density from a plurality of rows of apertures. The harmonization of the printed density from apertures from different rows is accomplished by an improved method of controlling the amount of pigment particles transported through the apertures of each row. The method takes into account which row the aperture belongs to and how the rows are positioned in relationship to the pigment particle feed.

Abstract: A direct electrostatic printing device and method for printing an image to an information carrier with increased density harmonization. This is attained by measuring the behavior of the apertures and subsequently adjusting the control parameters of at least the diverging apertures. The measurement of the behaviour of the apertures is suitably performed by scanning a known print sample with a predetermined density. The scanned values are inverted around a predetermined value for which no compensation is done to create a compensation function. At least the apertures which have a behavior which diverges from a predetermined behaviour are compensated according to the compensation function, thereby enabling an increased density harmonization. The compensation function can preferably be signal processed by, for example, a low pass filtering.

Abstract: An image recording apparatus includes a toner particle source for delivering charged toner particles to an image receiving medium. The image recording apparatus further includes a printhead structure arranged between the toner particle source and the image receiving medium to modulate a transport of toner particles from the particle source to the image receiving medium. The printhead structure includes a substrate of electrically insulating material having a first surface facing the toner particle source and a second surface facing the image receiving member. A first cover layer of electrically insulating material is arranged on the first surface of the substrate. A plurality of apertures are arranged through the printhead structure.

Abstract: An image recording device and method for recording an image onto an information carrier. The intermediate image receiving member is flexible under a tension and has a first face and a second face. A pigment image is formed on the first face of the intermediate image receiving member, which pigment image is subsequently transferred to an information carrier.

Abstract: A movable printhead having a screen or lattice-shaped control electrode matrix prints each page as a series of narrow bands across the width of the page. An information carrier such as paper is placed between a back electrode and the control electrode matrix, both of which are connected to voltage sources. Voltage sources connected to the control electrode matrix at least partially open and close passages through the control electrode matrix. Charged pigment particles attracted from a particle carrier through open passages are deposited on the information carrier to form visible images. In one embodiment, a particle carrier is rotated in opposite directions in response to the direction of movement of the printhead. In another embodiment, a cleaning assembly having a magnetic roll and located outside the printing area removes unwanted pigment particles from the control electrode matrix.

Abstract: An image recording device and method for recording an image to an information carrier. An intermediate image receiving member and a printhead structure move relative to each other during recording. The image recording device comprises an intermediate image receiving member position measuring means for measuring the position of the intermediate image receiving member in relation to the apertures to thereby via the control unit be able to synchronize the selective opening and closing of apertures through a printhead structure according to the relative movement of the printhead structure and the intermediate image receiving member to thereby enable the formation of a pigment image at a predetermined position on the intermediate image receiving member in view of the image which is to be recorded. The pigment image is subsequently transferred to an information carrier.

Abstract: An image recording device and method for recording an image to an information carrier. An intermediate image receiving member has a first face and a second face. The printhead structure is placed inbetween a pigment particle source and the first face of the intermediate image receiving member. The image recording device comprises a pressure changing means which can create a pressure difference on the side of a second face of the intermediate image receiving member in the vicinity of apertures used for pigment particle control. The intermediate image receiving member comprises a cleaning area for cleaning purposes and a separate image area intended for reception of pigment particles for formation of a pigment image thereon.

Abstract: A method and device for charging and feeding toner particles in a printing device include at least one printer unit. The toner unit includes at least one container, one back electrode and one control electrode provided with apertures and electrodes. The toner particles are transported to an information carrier, which is insertable between said container and the back electrode. A toner carrier material is provided substantially coplanar to the electrode unit to dispense toner particles. The toner carrier material is being entirely or partly conductive. The toner carrier material is brought substantially into direct contact with the control electrode unit. The toner particles are successively fed towards the control electrode unit by an external force.

Abstract: A direct electrostatic printing method and apparatus decrease the adhesion force of toner particles on a toner particle source. The method includes the steps of coating the toner particle source with a plurality of layers of toner particles and vibrating the toner particle source so that the toner particles break up to form one fluidised layer of toner. The toner particle supply apparatus includes a toner feed source supplying toner particles to a rotating developer sleeve to form a multilayer coating of toner particles on the developer sleeve. A vibration generating device is arranged adjacent to, or on a surface of the developer sleeve to break up the toner particles to form one fluidised layer of toner.

Abstract: The present invention relates to a direct electrostatic printing method, in which a stream of computer generated signals, defining an image information, are converted to a pattern of electrostatic fields which selectively permit or restrict the transport of charged toner particles from a particle source toward a back electrode and control the deposition of those charged toner particles in an image configuration onto an image receiving medium. Particularly, the present invention refers to a direct electrostatic printing method performed in consecutive print cycles, each of which includes at least one development period (t.sub.b) and at least one recovering period (t.sub.w) subsequent to each development period (t.sub.b), wherein the pattern of electrostatic fields is produced during at least a part of each development period (t.sub.

Abstract: A printhead structure for a direct electrostatic printing device selectively conveys a stream of charged toner particles from a particle source directly onto an image receiving substrate. The printhead structure includes an electrode plate having openings which surround the apertures. A voltage applied to the electrode plate causes a converging electric field to applied to the toner particles passing through the apertures. The converging electric field causes the toner particles to converge toward respective central axes of the apertures to thereby focus the stream of toner particles. The focusing of the toner particles considerably reduces the dot sizes on the printed image. The use of the printhead structure results in increased print resolution and improved image quality.

Abstract: A printhead structure and a method are used in direct electrostatic printing wherein streams of charged toner particles from a source of toner particles are directed onto an image carrier, such as a sheet of paper. A first set of print electrodes surround apertures through which the streams of toner particles flow. Voltages are selectively applied to the print electrodes to control the flow of toner particles through the respective apertures. A set of deflection electrodes are also associated with the apertures. Deflection voltages from at least one deflection voltage source are applied to the deflection electrodes to increase the convergence of the toner particles onto the information carrier and also to control the trajectories of the toner particles onto predetermined dot locations on the information carrier so that each aperture may provide toner particles to multiple lateral locations on the information carrier.

Abstract: The present invention refers to a direct printing method in which charged particles are transported from a particle source and deposited in an image configuration onto an information carrier. Printing is achieved in subsequent print periods by consecutively connecting variable voltage sources to complementary subsets of electrodes while supplying screen voltages to the electrodes of the remaining subset(s) to prevent interaction between adjacent electrostatic fields.

Abstract: A print head structure including:a particle source for delivering charged particles to an information carrier;a control unit for controlling transfer of the charged particles from the particle source to the information carrier, the control unit being arranged on a carrier sheet of flexible non-rigid material; anda support element for supporting the control unit in a predetermined position in relation to the particle source, the support element comprising a guiding edge, whereby the carrier sheet is fixed to the support element along said guiding edge with a portion of the carrier sheet carrying the control unit protruding beyond said guiding edge.

Abstract: A print head structure includes a support device which supports a flexible control unit in a predetermined position in the print head structure. The support device is in the form of a rigid trough-shaped frame having a longitudinal dimension and a transverse dimension and further having two longitudinally extending side walls. The support device further has a bottom portion between the two side walls, an outer surface and an inner surface. A longitudinally extending slot is provided in the bottom portion of the support device. The slot extends through the support device between the inner surface and the outer surface. The support device further includes a fastener for maintaining the flexible control unit in contact with the bottom portion of the support device. The flexible control unit bridges the slot in the bottom portion.