Abstract: A transport system for transporting sheet media in an image transport apparatus. The transport system comprises a drive section, and at least one wheel drivingly connected to the drive section. The wheel is disposed to contact the sheet media for transporting the sheet media generally in a process direction in the image transport apparatus, when the wheel is driven by the drive section. The wheel is steerable. The wheel is steered for orienting the wheel in a predetermined direction and for controlling a direction of travel of the sheet media relative to the process direction.

Abstract: An electrostatic recording medium includes a charge retentive layer located on a conductive substrate. An image recording surface on the charge retentive layer includes an array of discrete, conductive segments present in the image recording surface. A multiple electrode assembly having an array of recording electrode tips may be aligned for engagement with the image recording surface. Relative movement between the recording head and the electrostatic recording medium may be provided in such a manner that certain members of the recording electrode tips momentarily achieve Ohmic contact with respective elements of the discrete conductive segments present in the image recording surface. A latent image may be created in the electrostatic recording medium as the charge retentive layer receives an imagewise pattern of localized, discrete charges according to a variable voltage potential present at the tips of the recording electrode during the respective moments of Ohmic contact.

Abstract: A raster output scanner in which both the start-of-scan and the beam intensity of a laser beam are determined using a single photodetector. The raster output scanner has a laser source for generating a laser beam; a rotating polygon for sweeping the laser beam along a scan line plane, an optical fiber with a light receiving end positioned at a known position in the scan line plane and which intercepts at least a portion of the sweeping laser beam, and a photodetector for converting the intercepted laser beam into a beam current. The raster output scanner further includes both a scan detection circuit for producing a star-of-scan signal from the beam current and a beam intensity circuit for producing an electrical output which depends upon the magnitude of the beam current.

Abstract: A magnetically actuated ink jet printing device for use in an ink jet printer ejects ink droplets by deforming a diaphragm with the force generated on an electrode in a magnetic field when an electric current pulse is applied thereto. In one embodiment, the diaphragm of the device is provided by anisotropically etching a silicon substrate with an etch stop which provides a thin membrane of silicon material for use as the diaphragm. An electrode having an input and output terminal is patterned over the diaphragm and a sacrificial layer is deposited over the silicon substrate surface containing the diaphragm. The sacrificial layer is patterned to subsequently provide the ink ejection chamber over the diaphragm. A patternable layer is deposited over the silicon substrate surface including the sacrificial layer and patterned to provide the nozzles and expose the electrode terminals. The sacrificial layer is removed and an ink supply is connected to the space previously occupied by the sacrificial layer.

Abstract: An imaging system having a raster output scanner that produces high quality scan lines comprised of evenly spaced pixels. The raster output laser device is modulated in accordance with a variable frequency pixel clock that is derived from a high frequency oscillator using a dual modulus programmable divider that is controlled by a state machine. In turn, that state machine is controlled by information stored in a memory. The variable frequency pixel clock compensates for scan line nonlinearity, polygon facet errors, and/or scan line magnification.

Abstract: A development system is which includes a developer roll with a magnetic sleeve. The sleeve has a static magnetic field pattern for transporting developer material to a development zone; and a magnetic system for generating a superimposed alternating magnetic field to agitate developer material in the development zone in order to produce a charged toner cloud intended for the non-interactive development of latent electrostatic images.

Abstract: A development system is disclosed including a developer roll adapted for depositing developer material on an imaging surface having an electrostatic latent image thereon. The development system which includes a developer roll with a magnetic sleeve having a static magnetic field pattern for transporting developer material to a development zone. In operation the stationary magnetically patterned sleeve holds a thin well-defined blanket of magnetic developer on the sleeve surface. Magnetic assembly rotates and thereby generating a tangential magnetic field to move the developer blanket along the surface of sleeve; The developer blanket passes over zones on sleeve where developer material is picked up, self metering, mixing, blanket homoginization, tribo charging and developer transport occurs. The developer blanket moves to the development zone which is defined by a planar portion on the sleeve; parallel and adjacent to the imaging surface whereupon the blanket is compressed.

Abstract: In a raster output scanning apparatus including a laser diode adapted to output a writing beam, a reflex circuit controls the laser diode. A sensor diode is positioned to receive a portion of light flux from the laser diode while the laser diode emits the writing beam to expose one pixel area on a photosensitive surface. An accumulator associated with the sensor diode accumulates charge created by the sensor diode resulting from light flux from the laser diode. A comparator associated with the accumulator monitors charge accumulated on the accumulator and arrests the source of light flux when the charge accumulated on the accumulator reaches a predetermined threshold level.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with an electric field to assist in transporting the marking particles from the donor roll to a development zone adjacent the surface. The donor roll includes a rotatably mounted body and a first electrode member mounted on the body. The donor roll further includes a second electrode member mounted on the body and spaced from the first electrode member and a resistive member electrically interconnecting the first electrode member and the second electrode member so that when an activation potential for creating an electric field is applied to the first electrode member a portion of the potential will be transferred to the second electrode member creating an attenuated field.

Abstract: A development system is disclosed including a developer transport adapted for depositing developer material on an imaging surface having an electrostatic latent image thereon, said developer transport including a core; a magnetic transport member rotating about said core wherein said magnetic transport member has a static magnetic field pattern for transporting developer material to a development zone; and a magnetic system for generating a superimposed alternating magnetic field to agitate developer material in said development zone.

Abstract: A development system is which includes a flexible belt having a magnetic surface. The belt has a static magnetic field pattern for transporting developer material to a development zone; and a magnetic system for generating a superimposed alternating magnetic field to agitate developer material in the development zone in order to produce a charged toner cloud intended for the non-interactive development of latent electrostatic images.

Abstract: A raster output scanner for use in an electrophotographic printer uses two light sources to create two scan lines on a photoreceptor simultaneously. The two light sources are operated in an alternating fashion, and the intensity of the light sources is monitored by a single sensor. The sensor is associated with a reflex-based exposure control system, which operates to shut off a particular light source when the exposure created by the light source reaches a threshold level.

Abstract: A fiber optic detection system is used in a color reproduction device to generate color image registration signals. In one embodiment a retroreflector is positioned beneath the photoreceptor belt, the retroreflector being periodically visible through holes formed in a non-image area of the belt. An optical fiber directs flux from a light source onto the photoreceptor belt and periodically illuminates the retroreflector. Light is preferentially reflected back into the fiber with a portion being coupled to a photosensor to provide a signal used for registration purposes. In another embodiment, a plurality of optical fibers are bundled together to form a trunk at the belt illumination end with two branches functioning as the light input and detecting ends. In a still further embodiment, retroreflective marks are formed directly on the surface of a photoreceptor; the several fiber optic embodiments are used to detect the formed marks.

Abstract: A technique for achieving both start-of-scan detection and dynamic beam intensity regulation in a multiple laser beam raster output scanner using a single photodetector. The raster output scanner includes a source or sources of a plurality of laser beams, a rotating polygon having at least one reflecting facet for sweeping the laser beams to form a scan line path, and a photodetector for receiving illumination from the multiple laser beams and for converting those beams into beam-dependent electrical currents. The raster output scanner further includes a scan detection circuit for producing a start-of-scan signal from the beam dependent current, and a beam intensity circuit for producing an electrical output signal which depends upon the difference in beam intensity of at least two of the laser beams. Beneficially, the raster output scanner also includes an optical fiber that collects a portion of the light flux in the sweeping laser beams which directs the light flux onto the photodetector.

Abstract: A control system for the laser diode of a raster output scanner, such as used in a laser printer, uses reflex exposure control and a high-speed drive circuit. With the creation of each pixel on the photoreceptor, a sensor receiving some of the light flux from the diode accumulates charge on a capacitor, and when the charge on the capacitor exceeds a predetermined amount, a reflex circuit acts to shut the laser diode off. The laser diode is modulated via a high-speed trigger circuit wherein the diode is maintained just below its lasing voltage.

Abstract: A raster output scanner having a laser diode which generates a laser beam with a controlled beam intensity. The raster output scanner includes a time base generator which divides time into a sequence of periods; a laser diode; a current driver which applies laser excitation current to the laser diode in selected pixel periods, wherein the drive current causes the laser diode to generate a laser beam, and wherein the drive current depends upon a control input; a latent image producing surface; and a raster scanner for sweeping a focussed laser beam in scan lines across the latent image producing surface, wherein the time required to complete a scan line is a N pixel periods.

Abstract: A device for depositing charge on a charge retentive surface including an insulative support substrate coated with a layer of highly resistive material and a high voltage bus coupled thereto for providing a high voltage potential across the resistive material layer. The resistive charging device is positioned in contact with or in close proximity to a charge retentive surface to provide a uniform charging potential for depositing ions onto the charge retentive surface.

Abstract: A drive circuit enables high-speed modulation of a laser diode. A transistor is associated with the laser diode. The transistor input is supplied with a constant bias current just below the lasing condition of the diode, and also to one or more switching currents which are shunted to the transistor input through Schottky diodes. This high-speed circuit can be used, for example, for modulating a writing beam in a "laser printer," or in a magnetic driver for a disk writer, or in fiber-optic communication.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with an electric field to assist in transporting the marking particles from the donor roll to a development zone adjacent the surface. The donor roll includes a rotatably mounted body and a first electrode member mounted on the body. The donor roll further includes a second electrode member mounted on the body and spaced from the first electrode member and a resistive member electrically interconnecting the first electrode member and the second electrode member so that when an activation potential for creating an electric field is applied to the first electrode member a portion of the potential will be transferred to the second electrode member creating an attenuated field.

Abstract: A xerographic print engine includes a rotatable photoreceptor belt. The photoreceptor is exposed by delivering energy to the inward-facing side of the belt, and the electrostatic latent image is developed by applying toner to the outward-facing side of the belt. The system is particularly useful for liquid-development based xerographic systems, as multiple layers of toner can be accumulated on the outward-facing side of the photoreceptor belt without interfering with subsequent exposure steps. A cylindrical lens is in contact with the photoreceptor belt and is adapted to focus light from a light source at a developing region of the photoreceptor belt.