Abstract: A high viscosity, high solid volume liquid ink for use in electrophotographic printing systems. A silicone oil carrier material is combined with toner particles (including pigment, binder polymers and charge control agents) in a ratio of about 45% toner particles to 55% carrier liquid. The resultant ink preferably has a viscosity in the range 30000 to 50000 cs. The high viscosity ink of the present invention is preferably applied to a photoconductor material having a latent charged image thereon and a thin pre-wet material applied thereto. The pre-wet material is preferably a low viscosity silicone oil material. The composite layer of the combined low viscosity pre-wet and high viscosity ink permits the polymerized toner particles to migrate toward the latent charged image on the photoconductor surface. The high viscosity ink of the present invention helps maintain uniform dispersion of the toner particles in the liquid carrier.

Abstract: An electrographic printing apparatus comprises a rotatable charge bearing member, a rotatable roller assembly which applies a chargeable pre-wetting oil to the surface of the charge bearing member, a charger assembly which applies uniform charge to the surface of the charge bearing member and/or the pre-wetting oil coating, and a light source which discharges selected areas on the charge bearing member and/or the pre-wetting oil to produce a latent electrostatic image thereon. The electrographic printing apparatus further comprises a liquid development system comprising an ink head assembly which applies liquid toner to the charge bearing member thereby developing the latent electrostatic image, and a rotatable transfer member which receives the developed image from the charge bearing member and then transfers it to a substrate such as paper. The electrographic printing apparatus may also be adapted to produce color images on the substrate.

Abstract: An apparatus and method for producing an electrostatic image is disclosed. A thin layer of hydrophobic particles is coated on the surface of the charge bearing member which can be a photoconductor or a dielectric. The hydrophobic particles may also be used on the developer roller which applies the toner. A liquid toner made substantially of a hydrophilic liquid, such as water, and suspended pigment binders is used. The invention is applicable to both one and multiple color systems.

Abstract: An electrophotographic typewriter comprises a housing on which are mounted an alphanumeric keyboard, a flat-plane display unit, a paper feed tray and a paper output tray. A paper feed path is routed through an electrographic print unit, located in the housing, and comprises a photoconductive drum surrounded by a charging unit, an optical print head, a developing unit, a transfer unit, an erasing unit and a cleaning unit arranged in sequence about the photoconductive drum. An electronics package processes the alphanumeric input data to generate the flat-plane display and the outputs to the optical print head. Hard paper copy is produced where the paper feed path passes between the photoconductive drum and the transfer unit.

Abstract: An electrographic printing apparatus capable of functioning as a copier, printer, and telefax machine is disclosed. The electrographic printing apparatus includes a photoconductive member, preferably a horizontally mounted photoconductive belt, a developer unit for developing an electrostatic latent image on the photoconductive member, and a biased transfer roller to transfer the developed electrostatic latent image to a sheet of copy material. The apparatus also includes an optical print head which can receive information from a local or a remote source to form the electrostatic latent image on the photoconductive member and thus act as a printer. The apparatus further includes a device for scanning an original document and for projecting the scanned image either onto the photoconductive member or onto a CCD linear array. When the scanned image is projected onto the photoconductive member, a copy of the original document is made.

Abstract: An electrographic printer/copier capable of producing color prints is disclosed. The color printer/copier comprises a housing, a source of paper and an output for the paper after it is imprinted, a photoconductive member, and a developer unit containing toners of multiple colors. On successive revolutions of the photoconductive member, the developer unit applies a different colored toner to the photoconductive member. After each revolution of the photoconductive belt, the image developed in a particular color is transferred to and retained on a transfer belt. When all of the different colored images have been transferred to the transfer belt, a sheet of paper is brought into contact with the transfer belt and the fully developed color image is transferred to the sheet of paper. In a preferred embodiment, the photoconductive member is a vertically aligned photoconductive belt. The transfer belt is horizontally aligned and located above the photoconductive belt.

Abstract: A multiple chip LED linear array including 2048 elements is achieved by a unique wafer dicing technique which allows LEDs in abutting chips to be separated by the same distance as adjacent elements on a single chip. The linear array is employed in photocopy apparatus to discharge a linear segment of a photosensitive drum.

Abstract: An electrographic printing apparatus includes a housing, a source of paper, an output receptacle for receiving the paper after it is imprinted, a photoconductive member for storing a latent electrostatic image, a developer unit for developing the latent electrostatic image, and a charged transfer belt disposed opposite the photoconductive member. The charged transfer belt serves to transfer the developed image from the photoconductive member to the paper, and to transport the paper after it is imprinted to a fusing station. The paper path is located near the top of the housing for easy access in case of a paper jam. The paper path includes a sharp separation angle from the photoconductive member in order to decrease the dwell time of the paper against the photoconductive member. Desirably, the photoconductive member comprises a photosensitive drum of relatively small diameter, for example, on the order of 30-80 mm in diameter.

Abstract: A cleaning device for removing residual developer particles from a photoconductive element, such as a photoconductive belt, comprises a cleaning sleeve having a length substantially equal to the width of the photoconductive element. The cleaning sleeve includes a thin screen portion having apertures therein. The screen portion is maintained in contact with the photoconductive element. A biasing voltage is applied to the cleaning sleeve. Developer particles pass through the apertures in the screen portion. An auger is located in the interior of the cleaning sleeve. The auger transports the collected developer particles out of the cleaning sleeve where the particles may be either recycled or discarded.

Abstract: An electrographic printing apparatus capable of duplex printing comprises a housing, a source of copy material and an output tray for receiving such copy material after it is imprinted, and a photoconductive member for storing a latent electrostatic image of the information to be imprinted. The printer/copier has first and second paper paths located near the top of the housing so that access to the paper may be achieved from the top of the housing. A photoconductive member is located below the first paper path and comes into contact with a first side of the paper from below in a transfer zone located in the first paper path to imprint the first side of the paper. The second paper path is operative to receive paper after it has passed through the transfer zone and information has been transferred to the first side of the paper.

Abstract: An electrographic printing apparatus is capable of functioning as a copier, printer, and telefax machine, and is also capable of duplex printing. The electrographic printing apparatus includes a photoconductive member in the form of a disposable cassette which is mounted at an angle in the housing. The apparatus include an optical print head which can receive information from a local or remote source to form an electrostatic latent image on the photoconductive member and thus act as a printer. The apparatus also includes a device for scanning and digitizing an original document. When the digitized image is transmitted to the optical print head, a copy of the original document is produced. When the digitized image is transmitted over the telephone lines to a remote receiver, the apparatus functions as a telefax machine.

Abstract: A device for removing residual particles from a photoconductive member comprises a fur brush in contact with the photoconductive member, a metal roller in contact with the fur brush, and a scraper blade in contact with the metal roller. The fur brush is maintained at a first biasing voltage, e.g., +50V, while the metal roller is maintained at a second biasing voltage which is of the same polarity but greater in magnitude than the first biasing voltage, e.g., +150V. The fur brush attracts residual particles from the photoconductive member while the metal roller attracts residual particles from the fur brush. The scraper blade scrapes the residual particles from the metal roller, the particles falling into a conveying auger for recycling.

Abstract: A paper cassette for storing and supplying paper to a smart printer or copier includes a frame for holding the paper, a movable longitudinal paper guide within the frame adjustable to the length of the paper, and a pair of movable horizontal paper guides within the frame adjustable to the width of the paper. The two movable horizontal guides are linked together so that they move symmetrically with respect to a longitudinal central axis of the frame. The longitudinal paper guide is adjustable independently of the adjustment of the pair of horizontal paper guides. The cassette further includes a first sensor connected to the longitudinal guide and a second sensor connected to one of the horizontal guides. These sensors travel along first and second predetermined paths in conjunction with movements of the longitudinal paper guide and the horizontal paper guides so that the positions of the paper guides are communicated to a controller which automatically formats the printing on the paper.

Abstract: An electrographic printing apparatus capable of duplex printing comprises a housing, a source of copy material and an output tray for receiving such copy material after it is imprinted, and a photoconductive member for storing a latent electrostatic image of the information to be imprinted. The printer/copier has first and second paper paths located near the top of the housing so that access to the paper may be achieved from the top of the housing. A photoconductive member is located below the first paper path and comes into contact with a first side of the paper from below in a transfer zone located in the first paper path to imprint the first side of the paper. The second paper path is operative to receive paper after it has passed through the transfer zone and information has been transferred to the first side of the paper.

Abstract: An electrographic printing apparatus comprises a photoconductive member surrounded by a charging unit, an optical print head, a developing unit, a transfer unit, a cleaning unit, and an erasing unit arranged in sequence about the photoconductive member. Paper travels along a planar path across the top of the photoconductive member and the developed image is transferred to the underside of the paper. In a preferred embodiment, the photoconductive member comprises a vertically mounted photoconductive belt. By providing a separate and independent cleaning unit, the electrographic printing apparatus is capable of producing one sheet of copy material per revolution of the belt.

Abstract: An electrographic printing apparatus capable of functioning as a copier, printer, and telefax machine is disclosed. The electrographic printing apparatus includes a photoconductive member, preferably a horizontally mounted photoconductive belt, a developer unit for developing an electrostatic latent image on the photoconductive member, and a biased transfer roller to transfer the developed electrostatic latent image to a sheet of copy material. The apparatus also includes an optical print head which can receive information from a local or a remote source to form the electrostatic latent image on the photoconductive member and thus act as a printer. The apparatus further includes a device for scanning an original document and for projecting the scanned image either onto the photoconductive member or onto a CCD linear array. When the scanned image is projected onto the photoconductive member, a copy of the original document is made.

Abstract: A device for recycling residual developer particles which are removed from a photoconductive element by a cleaning unit in an electrographic copier or printer is disclosed. The device comprises a first tube connected to the cleaning unit and a second tube which is connected to the first tube and leads to the developer unit. The second tube is disposed along the developer unit. The residual particles are transferred from the cleaning device through the first tube and into the second tube. The second tube is provided with holes spaced at predetermined distances from each other. The residual particles fall through these holes and co-mingle with developer material stored in the developer unit. In a preferred embodiment, the holes increase in size as one goes along the second tube. In another preferred embodiment, an auger is used to deliver the residual particles to the first tube. A second auger is disposed within the second tube to move the residual particles over the holes.

Abstract: A multiple chip Led linear array including 2048 elements is achieved by a unique wafer dicing technique which allows LEDs in abutting chips to be separated by the same distance as adjacent elements on a single chip. The linear array is employed in photocopy apparatus to discharge a linear segment of a photosensitive drum.

Abstract: An electrographic printer/copier includes a paper path which is easily accessed from the top of the machine and permits copies to be collated automatically. The machine includes a paper tray which adjusts to organize successive pages into related reports.

Abstract: A developer unit for use in connection with an electrophotographic printer is disclosed. Toner is provided to the developer unit by means of a disposable cartridge so that maintenance requirements are significantly reduced. The developer includes a sensing circuit which measures the inductance of the toner/carrier mix and controls the rate at which toner is introduced into the toner carrier mix.