Abstract: A toner for electrographic printing includes a liquid carrier and a release agent added to the carrier to reduce the amount of carrier leaving the developer section, thus allowing operation at higher speeds and reducing the time and energy required for carrier removal in subsequent sections. An imaging system, or unit of an imaging system, and a method of imaging employ an imaging member such as a belt to form a liquid-toned image, to condition the image, and to transfer it to a print-receiving medium. The member moves through several sections, and transports liquid toner out of an image-developing section. In a preferred embodiment the release agent wets the imaging member, and has a higher boiling point than the carrier and a lower surface tension, though its viscosity may be higher. The release agent reduces carrier entrainment, and coats the imaging member, also enhancing transfer of the final print image. It may also counteract aging characteristics of the imaging member.

Abstract: A print head has a matrix array of charge generating loci defined by crossings of a first set of electrodes which are parallel to each other and extend across the region to be printed and a second set of electrodes that extend obliquely across the first electrodes so that the crossings are closely spaced lattice points. The charge deposited by a lattice point varies with the position of the first electrode defining the point, but the electrodes are arranged so charge carriers are generated or gated for projection onto a latent imaging member with local charge dot uniformity. In one embodiment of the invention, there are an odd number of first electrodes, and the second electrodes are arranged such that when electrodes are actuated, pairs of adjacent dots are deposited by pairs of lattice points having complementary variations in charge. As viewed or measured along the print line, each pair of deposited dots has a substantially uniform level of charge, and doubling and extreme discontinuities do not occur.

Abstract: A toner for electrographic printing includes a liquid carrier and a release agent added to the carrier to reduce the amount of carrier leaving the developer section, thus allowing operation at higher speeds and reducing the time and energy required for carrier removal in subsequent sections. An imaging system, or unit of an imaging system, and a method of imaging employ an imaging member such as a belt to form a liquid-toned image, to condition the image, and to transfer it to a print-receiving medium. The member moves through several sections, and transports liquid toner out of an image-developing section. In a preferred embodiment the release agent wets the imaging member, and has a higher boiling point than the carrier and a lower surface tension, though its viscosity may be higher. The release agent reduces carrier entrainment, and coats the imaging member, also enhancing transfer of the final print image. It may also counteract aging characteristics of the imaging member.

Abstract: An electrographic printing system moves a dielectric imaging member past a charge transfer print cartridge or bulk charging source, and a landing electrode arrangement directs charged particles with enhanced precision to dot positions on the imaging member. The arrangement includes a central, point-like, target electrode and a field electrode that, together with the target electrode, provides a corrective electric field component to form a focusing, or at least a non-diverging field over the target position. Field deflection artifacts such as "venetian blinding" are substantially corrected. The target electrodes are located behind the imaging member, in registry with the charging cartridge which is opposed to the other side of the member. Different landing electrode arrangements may include one- or two-dimensional arrays of targeting electrodes and are adapted to either bulk or pointwise arrays of charge emitter.

Abstract: An imaging system, or unit of an imaging system, and a method of imaging employing a single imaging member to form a liquid-toned image, to condition the image, and to transfuse it to a print-receiving medium. The member moves through three sections, with the image formed in the first section, then changing state in each successive section. In a preferred embodiment, a heat exchanger uses heat from the third section to extract the liquid carrier from the toned image while it is in the second section. Condensed carrier replenishes toner, cooling the first section. Multicolor printing is effected by employing several such units, one for each color, to transfuse colored images in succession onto a receiving member.

Abstract: A compact printer includes a print roll on which a latent image is deposited, toned, then heated and transferred in a "transfuse" step. A commutating heater selectively heats a surface sector of the rotating roll for transfusing the image and roll cleaning, and the roll body remains below a toner agglomeration temperature. The roll has a rigid core and a surface structure that includes a plurality of heater lines and a hardcoated elastomeric imaging layer covering the heater lines. The imaging layer includes a conductive sublayer and a dielectric surface layer, both having greater thermal conductivity than an outer region of the core so that heat from the heaters preferentially flows to the deposited toner image. The printer scrolls portions of a latent image, which is toned, heated and transferred onto a separate recording member to form a final image having, in general, a much greater surface area than the roll.

Abstract: A print cartridge contains a matrix array of electrodes which are energized to deposit a latent charge image. To make the cartridge, electrodes are fabricated on a sheet which is then deformed about a rigid spine. Certain electrodes are formed of plural segments, and the segments are electrically interconnected only after the sheet is deformed. This prevents strains introduced during manufacture from building up over large distances and pulling active electrode structures out of alignment. A preferred cartridge has an area of active electrodes, which is planar and undeformed. Lead-in electrodes extend through deformed regions of the sheet, and are conductively fastened to the active electrodes only after the sheet has been deformed about a rigid spine and the electrodes have attained a stable and unstressed position. The spine maintains the active electrodes in a precise plane, and accommodates pressure from spring-loaded electrical contacts without deflecting.

Abstract: Fusing apparatus for an electrographic printer, includes an abhesive belt for carrying and contacting a recorded image, a low temperature heater to fuse the image, and an assembly for synchronously moving a sheet in contact with the belt past the heater for an extended dwell time so that the toned image attains a fusing temperature as it resides in thermal contact with the heater along an extended transport path. The belt has a release coating of low surface free energy. Image transfer or fusing may be accomplished at sufficiently low belt temperatures that a single belt may be employed to effect imaging, toning, image transfer and fusing steps without impairing heat-sensitive toning assemblies, photoconducting elements, or other temperature-sensitive parts of the printer.

Abstract: A sheet transport for a printer moves the leading edge of a sheet along a short and substantially straight path while inverting the sheet side-to-side. An output path feeds back to the printer input so a second side is printed in the correct orientation. Preferably a non-inverting sheet transport feeds directly into the output path, so that a once-printed sheet is transported to another printer, or is returned to the printer for a second pass either inverted, or on the same side. A deflector curls the sheet over a bar onto a transport at a different level, and as the paper advances, its trailing edge is drawn over the bar, flipping the sheet over.

Abstract: An electrographic printhead is operated to focus charged particles on a print member. In one embodiment successive electrodes are maintained at potentials that define increasing electric field strengths in the successive regions along the particle trajectory. In another embodiment, a thick electrode face defines equipotential lines that shape a sharply focusing electrostatic field that penetrates the projection apertures of the printhead. Improved focusing diminishes charge spreading effects, and allows effective positioning of the printhead at greater spacings to reduce the risk of arcing without loss of print resolution.

Abstract: A driver for the finger electrodes in a charge-deposition print cartridge controls the finger potential between a printing and a non-printing state. All fingers are reset at once by a common power source, to which each is connected by a diode. Charge storage provided in each finger electrode line keeps the finger at a back-biased potential without deterioration by crosstalk until it is next positively driven to a printing state. Binary-coded drive data is checked for errors at the input, and the charge delivered to each finger is monitored at the output to identify data transmission or cartridge electrode faults.

Abstract: A printing system forms a first electrostatic latent image on a dielectric member and tones the image with a first toner. The toned image is then consolidated on the dielectric member, and one or more additional toners are applied to form a multiply-toned image which is then fused and transferred to a sheet. At intermediate stages of forming the multiply-toned image, the previously applied toner is melted and cooled to consolidate it. A dielectric belt with a fast thermal response time allows the multicolor image to be efficiently formed on the belt and all colors transferred to a paper sheet which is fed once through the machine. The belt may receive latent images from a photosensitive imaging drum of conventional type, or may itself be a photosensitive belt which directly receives an optical image. Preferably, however, the electrostatic latent images are deposited on the belt by one or more electronically controlled printhead arrays.

Abstract: A dielectric imaging member of a printer receives a latent charge image that is preferably projected as a plurality of charge dots from a multi-electrode printhead. The member has charging characteristics that diminish the normal electric field component at the edge of charge dots deposited on its surface. The dielectric constant of a surface layer of the imaging member decreases with depth, either continuously, or in a stepwise manner. Various printing aberrations, such as voids in grey-scale images, fringing rings about dots, dot spreading and filling between dots are corrected, so that compensating image coding of printhead actuation sequences is not required to deposit a faithful electrostatic latent image.

Abstract: A DC operated printhead emits electrons by field emission at each crossing of first and second electrodes. Plural small electrode sets consisting of a cathode emitting cone and an anode aperture form a gap which less than the electron mean free path in an ambient atmosphere, and the sets are preferably closely spaced to form a substantially collimated beam. A third electrode preferably accelerates and cleans up the beam. Different gases may be used to increase emission or transport efficiency, and enhance electrode lifetime.

Abstract: A printer has a print cartridge with a plurality of electrically isolated screen electrodes extending in parallel strips and maintained at different potentials to define a uniform electric field in the gap between a print cartridge and a latent imaging member curved about an axis parallel to the strips. As charge carriers are generated, the potentials on a plurality of control electrodes located between the charge carriers and overlying screen electrodes are controlled to provide a fixed bias. This assures gating of a uniform quantity of charge from different apertures of the print cartridge, as well as uniform size of the charge dots formed on the imaging member.

Abstract: An oscillation circuit having multiple separately addressable oscillator stages for applying RF voltage across selected capacitive loads where each stage includes a power driver, a transformer and a quench/clamp circuit. The oscillation circuit includes one enablement circuit responsive to an externally applied enablement signal and address signal and a common feedback circuit connected between one end of all of the transformers and the enablement circuit. An externally applied address signal and an enable signal selects a particular oscillator stage and initiates action of a power/driver circuit to provide an initial pulse of AC current through the associated transformer for a preset period and the feedback circuit detects negative zero crossovers of the waveform of current through that transformer primary to maintain actuation of the driver circuit for as long as the external enable signal is present.

Abstract: The flash units are housed in reflector assemblies and actuated in a sequence that entirely exposes both sides of the sheet while drawing a constant amount of electrical power. Constructions of the reflector include an extruded housing, snap-in replaceable reflector surfaces, and a manifold structure that achieves cooling, fume scavenging and paper flattening. In one embodiment a two-sided sheet moves past a pair of oppositely directed flash units which are powered by a single power supply. A specularly reflective surface provides a level of reflected illumination which complements the light received directly from the flash tube to provide a constant level of illumination and fuse a toned image.

Abstract: A photoconductive or magnetic filler allows a single thin belt to serve as the imaging element, i.e., as the latent and developed image carrier, as well as the element which transfers and fuses toner to a print. The transport member moves in a cyclic path to carry material from a first location to a second location maintained at a higher temperature, and counter-moving portions of the member are positioned to exchange heat with each other along an intermediate portion of the path, so that minimum energy is lost to the environment. In one embodiment as a printing apparatus, a belt transports a heat-fusible toner to a heated location where it is transferred and fused, i.e., transfused, as a print image to a sheet. Effective powder pick up and release is obtained in the printing apparatus with a transport member having an elastomeric layer of a softness which conforms to a receiving member of characteristic surface roughness, and a non-tacky outer coating which is harder than the elastomeric layer.

Abstract: A cartridge for use in charge transfer imaging comprising a flexible dielectric substrate carrying sets of driver electrodes and finger electrodes, the electrodes being separated by a dielectric layer. The respective electrodes extend in different directions to form a charge generating matrix in a first central portion generally corresponding to the extent of the dielectric layer. Each of the electrodes has individual contacts which extend to the sides of the dielectric layer. The flexible substrate is deformable from its natural planar form to a U-shape, the charge generating matrix and the dielectric layer being located on a first central portion of the substrate, and the contacts of the electrodes being located on second and third side portions of the substrate. A method of manufacturing the cartridge is also disclosed.

Abstract: A method and apparatus for converting data representative of a plurality of cells arranged independently of one another on a page into data is raster scan order for subsequent printing. Cell data for individual cells is fetched in an order dependent on the line of raster scan where the cell first occurs and the bit position for the first bit representing the cell. This cell data is compared with earlier fetched cells to build up raster scan lines from cells occuring in the lines.