Xerox Corporation

Joannes N deJong

Lloyd A Williams

Vittorio R Castelli

Barry M Wolf

Meng H Lean

Gerald A Domoto

John J Ricciardelli

Barry Paul Mandel

Stuart Alan Schweid

Steven Robert Moore

John F Knapp

Robert Michael Lofthus

Thomas Acquaviva

Grace T Brewington

Jan Bares

Injae Choi

Marina L Tharayil

Michael J Savino

Edward John Solcz

John Buranicz

Edward J Wrobbel

Johann H Metternich

Gerhard H Bay

A reversing apparatus within a media path comprises an input nip moving sheets of media in a first direction, and a reversing nip positioned to receive the sheets of media from the input nip. The reversing nip stops the sheets and moves the sheets in a second direction opposite the first direction. Also included is an output nip positioned to receive the sheets of media from the reversing nip, and an actuator connected to the reversing nip. The actuator moves the reversing nip relative to a position of the input nip and the output nip, based on a characteristic of the sheets of media.

Inverter with adjustable reversing roll position

A method and apparatus for determining the lateral position of a moving sheet in a sheet registration system. A side edge sensor is moved from a known location until the side edge of the moving sheet is detected. A signal is generated indicative of the position of the side edge when it is detected. The position of the side edge as indicated by the signal is used along with skew of the sheet to determine the lateral position of the sheet.

Moving sensor for sheet edge position measurement

A printing system and method using alternating control modes for one or more, but not all, sheet transport devices in order to avoid contention. In a printer having first, second and third sheet transport devices in series (e.g., registration, image transfer and image fixing devices), the second device can always operate in a velocity control mode. However, the first and/or third devices can alternate between velocity and torque control modes. For example, the first device can operate in a torque control mode, when a sheet is concurrently engaged by both the first and second devices, and in a velocity control mode at other times. Additionally or alternatively, the third device can operate in a torque control mode, when a sheet is concurrently engaged by both the second and third devices, and in a velocity control mode at other times. Transition control modes can be implemented to generate smooth transitions between modes.

Printing system and method using alternating velocity and torque control modes for operating one or more select sheet transport devices to avoid contention

A sheet feeder is provided comprising at least two drives that drive a sheet of material along a paper path and at least two sensors that detect a lateral side of the sheet of material. A controller is connected to the two sensors and at least one of the drives. The controller varies the drive velocity of at least one of the drives to shift the lateral position of the sheet of material in a predetermined direction until one of the sensors detects the lateral side and then varies the velocity difference of the two drives to eliminate the skew of the sheet.

Sheet feeder

A multi-color electrophotographic printing machine in which the tangential velocity of the photoconductive drum in the transfer zone is greater than the tangential velocity of the transfer drum having the sheet receiving the transferred images thereon. A buckle is formed in the sheet after the transfer zone, resulting in the sheet being tacked to the developed image on the photoconductive member and moving at the same tangential velocity as the developed image. This is achieved by a transfer sheet having one end secured fixedly over an aperture in the transfer drum. The other end of the transfer sheet is resiliently secured to the transfer drum. The sheet of support material receiving the transferred images is secured at the leading edge to the transfer sheet. In this way, the transfer sheet and the sheet of support material may be induced to form a buckle after the transfer zone enabling the sheet of support material and the developed image to move at the same tangential velocity. By moving at the same tangential velocity, the image smear is eliminated during transfer.

Transfer system

A droplet-on-demand ink jet printer uses electrostatic tacking of a recording medium, such as paper, to achieve simultaneously precise holding of an aligned recording medium on a dielectric surface of a transport belt, thereby providing precise motion quality of the recording medium relative to the printer's printhead, and improved ink droplet placement on the recording medium. The transport belt is electrostatically charged with a charge of one polarity, so that an electrostatic pressure is generated which precisely holds the recording medium in an aligned position on the transport belt, after it is fed thereon, and concurrently induces a charge of opposite polarity on the ink droplets ejected by the printhead, thereby accelerating the droplets toward the recording medium. The accelerated droplets reduce transverse forces on the droplets, such as transverse airflows, and placement errors caused by the repulsion of incoming droplets by previously printed images are further reduced by migration of the charges of the printed droplets through the recording medium and consequent charge cancellation, so that droplet placement is improved.

Ink jet printer having improved ink droplet placement

An apparatus and method for registering and deskewing a sheet along a sheet path. A pair of drive spheres are located in the sheet path. When a sheet enters the nips formed by the spheres the sheet is driven until it is sensed by a sensor. The drive spheres are driven by a pair of wheels which allow the spheres to rotate about any axis through their center and parallel to the plane of the sheet. The spheres are driven such that the sheet is side registered and deskewed as it is moved along the sheet path. Constant feedback from the sensors to the drive controller allows the sheet to be registered in a very short distance and has the added benefit of self compensation for wear of the drive components. The wide registration and deskewing latitude of the device allows for the use of relatively inexpensive and low accuracy sheet drives preceding the device.

Process, lateral and skew sheet positioning apparatus and method

There is provided a calibration system for a deskewing and registering device for an electrophotographic printing machine. The method includes a.) moving a sheet from a first position to a second position along a paper path; b.) sensing the position of the sheet at the first position and the second position; c.) choosing a correction value to cause the sheet to change a lateral position from the first position to the second position; d.) repeating the moving, sensing, and choosing steps until a predetermined adjustment is made when moving the sheet from the first position to the second position to determine a proper calibration value.

Calibration method and system for sheet registration and deskewing

An apparatus and method for registering and deskewing a sheet along a paper path. A pair of independently driven selectively actuable nips are used to drive a sheet transverse to a paper path direction until the edge of a sheet is registered laterally and in skew. The transverse nips are then deactivated and a drive nip moves the sheet in a process direction along the paper path. A first transport sensor senses the lead edge of a sheet, a second sensor is used to also detect the lead edge of a sheet within a certain distance from the detection by the first sensor. The transport drive nip can then be adjusted based on the transport time between the first transport sensor and the second transport sensor so that the sheet arrives at a registration sensor at the prescribed time. This apparatus and method allows the use of simple point type sensors as opposed to more complex and expensive sensor arrays.

Agile lateral and shew sheet registration apparatus and method

A registering device for an electrophotographic printing machine. A steerable pair of drive nips is located in the paper path. A lead edge sensor detects when a sheet is within the steerable drive nips. The steerable nips are turned so that the sheet is transported toward a side registration sensor located in the paper path. When the side registration sensor detects the edge of the sheet the actuator causes the steerable nips to be straightened. The sheet may be forwarded to a second, higher accuracy registration device for final registration. The steerable nip device provides a course preregistration device which may utilize inexpensive and non complex components. This device also enables the use of less expensive components in the fine registration device as the range of correction required by the fine registration device can be much narrower due to the preregistration device.

Lateral sheet pre-registration device

A deskewing and registering device for an electrophotographic printing machine. A single set of sensors determine the position and skew of a sheet in a paper path and generate signals indicative thereof. A pair of independently driven nips forward the sheet to a registration position in skew and at the proper time based on signals from a controller which interprets the position signals and generates the motor control signals. An additional set of sensors can be used at the registration position to provide feedback for updating the control signals as rolls wear or different substrates having different coefficients of friction are used.

Sheet registration and deskewing device

A method and apparatus for simultaneously developing and transferring a liquid toner image. The method includes the steps of moving a photoreceptor including a charge bearing surface having a first electrical potential, applying a uniform layer of charge having a second electrical potential onto the charge bearing surface, and imagewise dissipating charge from selected portions on the charge bearing surface to form a latent image electrostatically, such that the charge-dissipated portions of the charge bearing surface have the first electrical potential of the charge bearing surface. The method also includes the steps of moving an intermediate transfer member biased to a third electrical potential that lies between said first and said second potentials, into a nip forming relationship with the moving imaging member to form a process nip. The method further includes the step of introducing charged liquid toner, having a fourth electrical potential, into the process nip, such that liquid toner sandwiched within the nip simultaneously develops image portions of the latent image onto the intermediate transfer member, and background portions of the latent image onto the charge bearing surface of the photoreceptor.

Method and apparatus for liquid image development and transfer

A method and apparatus is provided for controlling the transverse registration of an image area to be exposed on a longitudinally moving belt by providing belt edge profile data, detecting a lateral position of the belt during movement of the belt by measuring the lateral position of the belt edge, and adjusting the transverse location of the image on the belt to compensate for a difference between the detected lateral belt edge position and the belt edge profile data. In addition, a method and apparatus is provided for controlling the lateral position of a longitudinally moving endless belt by generating a steering command signal by calculating a difference between the detected first lateral position of the belt edge and the belt edge profile data corresponding to the first longitudinal position, and adjusting the lateral position of the belt by steering the belt in response to the steering command.

Method and apparatus for lateral registration control in color printing

A method and apparatus for controlling speed match between a photoreceptor and an intermediate transfer member to prevent image degradation by creating a deliberate speed mismatch. It has been found that slight variations in speed match between a photoreceptor and transfer member will maintain acceptable image quality, however, should the relative velocity between the members change sign, unacceptable image error results. The method herein comprises slewing the velocity of a photoreceptive member over a range of speeds while monitoring the output control signal current of a drive motor. The resulting control signal current has a large oscillation at the velocity at which the speed of the photoreceptor matches that of the intermediate transfer member. A controller is then used to maintain the motor velocity at a speed slightly less than or slightly greater than the intermediate transfer member speed so as to prevent a change in sign of the relative velocity between the two moving surfaces.

Apparatus and method to control and calibrate deliberate speed mismatch

An inductive-type rotary encoder includes a stator having at least one conductive pattern on one side thereof, and a rotor having another conductive pattern on one side thereof which faces the at least one conductive pattern of the stator. The conductive patterns are inductively coupled to one another so as to generate an output signal indicative of the angular position of the rotor relative to the stator. In order to reduce the overall size and number of parts required, the circuitry for energizing the stator conductive pattern(s) and for generating the output signal can be provided on a printed circuit board, the opposite side of which contains the at least one stator conductive pattern. In order to reduce noise as well as to reduce the first harmonic error, lead lines for attaching the stator and rotor conductive patterns to the controlling circuitry and a return line which extends along substantially the entire length of the rotor or stator conductive patterns and attaches to one of the lead lines are provided and specially located relative to undulations of the conductive patterns. Additionally, the length of spokes which define undulations of the respective rotor and stator conductive patterns can be controlled to improve the performance of the rotary encoder. A rotary encoder including inductively coupled rotor and stator conductive patterns for generating a relative angular position (or rotary speed) of the rotor relative to the staator, as well as stator and rotor index pulse patterns inductively coupled for generating an index pulse once per revolution of the rotor relative to the stator is also provided.

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Suffern, NY, United States of America

Joannes N deJong