Abstract: An apparatus for mechanically assisting the transfer of an image from an image bearing member onto a substrate. The apparatus includes a transfer assist blade that forces a substrate toward an image bearing member, a motor, a mechanical assembly for coupling the motor to the transfer assist blade such that motor operation changes the transfer assist blade force, and a controller that controls the motor operation. The controller might receive inputs from a substrate sensor, an operator control panel, and/or a service adjustment. The controller might use those inputs to control the motor operation, and thus the transfer force. Alternatively, the controller might control the transfer force as a result of the operation of the overall machine, such as by changing the transfer force during duplex printing or during the transfer of various color images.

Abstract: A digital LED printer having a printbar control architecture that enables multi-exposure levels and multiple gray levels for a LED printbar. Alight emitting diode printbar is aligned in an image exposure relationship with a photoreceptor. Video data signal comprised of multiple bits for each pixel are applied to a register/latch. The individual bits of the latched multiple bits for a pixel are applied to AND gates. Those signals are ANDed with multiple strobe line signals that are related to the status of the printer. The outputs of the AND operation are applied to an OR gate. The output of the OR gate is used to control the illumination from a light emitting diode. Beneficially, the characteristics of the light emitting diode are measured and stored such that the current applied to the light emitting diode can be adjusted such that the illumination from the light emitting diode is at a predetermined value.

Abstract: A color electrophotographic printing system that uses one switched developer power supply for all developers and that enables a reduced size by reducing the interdocument zone. The interdocument zone is reduced by using a developer order in which the last used developers in a development cycle is physically located first. Beneficially, the developer that is used first is physically located last.

Abstract: An apparatus for compensating LED printbars, and printers which use LED printbars, for aging. Changes in the slopes of the forward voltage drop verses forward current characteristics (the I-V characteristics) of the LEDs of the LED printbar are determined. The drive currents of the LEDs are then changed as a function of the changes in the slopes so as to compensate for changes in the LED light outputs.

Abstract: A multistation color electrophotographic printer having an erase lamp located opposed to or before the last physical developer housing, but after the first physical developer housing.

Abstract: This invention provides for duplex use of densitometers. An image is produced on a substrate, that substrate is brought back through the transfer station in a duplex fashion (that is, the substrate is inverted), and a sensor senses the image on the substrate. Beneficially, the sensor senses one or more parameters such as color registration, color occlusion/interference, black separation in color REaD printing, colorimetry, and the overall transfer and fusing process; and a printing process is controlled based on the sensed parameters.

Abstract: REaD(Recharge Expose and Develop) electrophotographic printing using additive color toners and inhibited image on image development. Inhibited image on image development is achieved by setting the exposure set points such that exposure losses incurred when imaging through previously developed toner reduces the electrostatic potential for developing over the developed toner, by using a DC corona system during recharging so as to enhance the voltage drop across the previously developed toner(s), and/or by increasing the developed toner mass to increase the thickness of the dielectric properties of the developed toner.

Abstract: Method and apparatus for implementing discharge and develop, REaD IOI electrostatic printing machines that determine image area charge potentials of without using potentials within interdocument zones. The method includes charging a photoreceptor's image area to a charge potential, interrogating the image data to be used to produce a latent image on that charged image area to identify a white section, exposing the charged image area according to the image data to form a latent image, determining the potential of the white section of the latent image, and equating the potential of the white section to the charge potential.

Abstract: A color REaD IOI system in which a light source illuminates the photoreceptor so as to erase that photoreceptor after the development of black toner but before exposure and development of the next color image.

Abstract: A color REaD IOI system in which the photoreceptor is DC only recharged between the development of the first toner layer and the subsequent exposure and development of the following toner layer. To assist the DC only recharge the photoreceptor and the first toner layer are beneficially erased prior to recharge. Beneficially, the photoreceptor is subsequent recharged prior to exposures for the other toner layers using a charging scheme that includes an AC charging device.

Abstract: A color REaD IOI system in which a light source illuminates the photoreceptor so as to erase that photoreceptor after the development of a first toner followed by a high slope AC corona system which recharges both the photoreceptor and first developed toner before exposure and development of the next color image.

Abstract: A scanning system that accurately positions a moving carriage assembly in two directions relative to a platen. Such a scanning system includes a frame that has a registration member that extends in the Y direction, and a platen whose plane is normal to the Z direction and which is attached to the frame. The platen receives a substrate in a predetermined position relative to the registration member. The scanning system further includes a base that has a first and second tilted surfaces that extend in the Y direction, and a moving carriage assembly that is disposed between the platen and the base. The moving carriage assembly includes a housing, at least one button connected to the housing, and first and second biased pivot arms with first and second rollers that ride on the first and second tilted surfaces. The biased pivot arms push the housing against the tilted surfaces such that the button contacts the platen and the registration member.

Abstract: A five cycle color electrophotographic printing architecture in which the transfer station is located downstream of the cleaning station.

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: Automated diagnosis of drive trains having electrically operated components based upon the ability of a first servo motor to rotate a second servo motor when both servo motors are selectively coupled to the drive train. Beneficially, the status of the drive train is sent to a remote location using a data link.

Abstract: A substrate transport assembly having an air mover that moves air through an air housing such that a substrate is biased against a drive member. The substrate assembly further includes an air plenum that receives moving air and directs that air along a predetermined path. The air plenum expands when air is moving but is otherwise collapsed.

Abstract: Diagnosis of servo motor driven drive train problems based upon changes in the rotational velocity of the servo motor as electrically operable drive line components are selectively engaged. The unloaded (unloaded) rotational velocity of a servo motor is determined, a drive train component that couples a load to the servo motor is energized, the change in the rotational velocity of the servo motor caused by engaging the drive train component is determined, and, if the servo motor rotational velocity falls outside of a predetermined limit the drive line fault that causes that rotational velocity to fall outside of that limit is identified. Beneficially, the status of the drive train is sent to a remote location using a data link.

Abstract: Compact raster scanner assemblies, and systems which use such assemblies, having a laser source generating laser light; a photoreceptor moving in a process direction; and a raster scanner raster sweeping the photoreceptor. The raster scanner includes a rotating polygon, an F-.theta. scan lens in the sweep plane, and a first folding mirror positioned along a first axis for reflecting laser light passing through the F-.theta. scan lens toward the photoreceptor. The first folding mirror being aligned along an axis which is at an angle with both the process direction and the resulting fast scan direction. The raster scanner assembly further including a second folding mirror for receiving laser light reflected by the first folding mirror and for directing that laser light toward the photoreceptor such that the laser light sweeps across the photoreceptor in a direction perpendicular to the process direction.

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: Printing machines which incorporate a transfusing station having a transfusing member with a resistive heater layer, a substrate, and a release layer. The transfusing station is entrained between at least two electrically conductive contact members, such as rollers, which electrically contact the heater layer. An electrical source sends current through the conductive rollers and the heater layer, heating that layer, the substrate, the release layer, and any toner on the release layer. A backup roller adjacent the transfusing member and the conductive rollers induces pressure on marking substrates which pass between the backup roller and the transfusing member. The combination of heat from the heater layer and pressure induced by the backup roller causes any toner image on the transfusing member to fuse onto the marking substrate. The release layer assists in transferring the toner onto the marking substrate.