Xerox Corporation

Barry M Wolf

Lloyd A Williams

Vittorio R Castelli

Joannes N deJong

Joannes N M deJong

Robert Michael Lofthus

Harold M Anderson

Edward John Solcz

David Kalman Biegelsen

Warren Bruce Jackson

Stuart Alan Schweid

Meng H Lean

Sudhendu Rai

Gerald A Domoto

Elias Panides

Michael J Savino

John J Ricciardelli

Joannes N De Jong

Color electrophotographic printers having latent image positions synchronized with start-of-scan signals. A laser source projects a laser beam onto a multifaceted rotating polygon that sweeps that beam in a scan line across a moving photoreceptor. A start-of-scan detector produces start-of-scan signals when the laser beam is in position to write a scan line. A belt sensor produces belt signals when indicia on the photoreceptor passes a reference position. A controller receives the belt signals and the start-of-scan and then adjusts the photoreceptors rotational velocity such that the belt signals are an integral multiple of the start-of-scan signals. To reduce the impact of drive roller eccentricities on belt signal to start-of-scan signal timing, the perimeters of photoreceptor roller elements are sub-multiples of the photoreceptor length.

Color image registration based upon belt and raster output scanner synchronization

An apparatus and method are provided for the use of an optical sensor to determine the position of a printing device relative to a piece of paper or a paper-handling surface. The optical sensor reads marks to detect movement and/or direction of movement or spacing of imprints on the paper. Benefits include swath stitching calibration, color to color registration, producing printing device alignment data and generating information for printing device firing signals. The present invention is applicable to a wide field of printing technologies, including, but not limited to, acoustic ink printing, thermal ink jet printing, piezo ink jet printing, ionographic printing and a variety of other printing technologies involving the need for positioning a printing device relative to a piece of paper.

Stitching and color registration control for multi-scan printing

Systems and methods are provided that improve the registration between the color separation images. The systems and methods control the output of the image data for one or more of the color separation images and the velocity of an image-carrying member to remove or reduce registration offsets based on determined position and velocity of the image-carrying member. A position-determining sensor on an image-carrying member device module is used to determine the process-direction position of the image-carrying member to provide real time motion information by simultaneously sensing a plurality of position-determining marks. A position-determining controller determines the process-direction position of the image-carrying member by detecting the plurality of position-determining marks using the position-determining sensor and averaging or correlating the detected data.

Surface position and velocity measurement for photoreceptor belt

A method and apparatus for periodically upgrading the color calibration for an electrophotographic printer (or other digital document viewing device) using a color compensator is proposed. Initially, a fairly large number of colors are printed and measured. From this information a color correction is determined and stored in a high density compensator. A small number of color patch samples are printed and measured at regular intervals during the use of the printing machine. This low density information which is periodically updated compensates for slow drift in the high density compensator. Each time the small patch printing process is repeated a different set of colors is used to assure that all regions within the gamut of the machine are updated uniformly. A similar process can be used to maintain the gray scale fidelity in a black and white printer or digital document display device.

On line compensation for slow drift of color fidelity in document output terminals (DOT)

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

A method of controlling the movement of copy sheets along a copy sheet path by providing a target by a high level controller for the movement of copy sheets within the copy sheet path and controlling movement of copy sheets within segments of the copy sheet path. Movement in each segment is controlled by subcontrollers activating segment drives. Feedback data are conveyed to the high level controller and to other subcontrollers on the movement of copy sheets within segments of the copy sheet path and copy sheet movement is adjusted by the copy sheet drives of selected segments of the copy sheet path in order to achieve the target.

Hybrid hierarchical control architecture for media handling

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 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

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.

Inductive type incremental angular position transducer and rotary motion

A method and apparatus provides on-line calibration of low cost encoders by interfacing an encoder with a microprocessor and driving a shaft to which the encoder is attached at a slow constant speed and at a fast constant speed. Data is collected by the microprocessor for the slow and fast speeds and a mathematical analysis is performed which determines the torque disturbances occurring at each point in the rotational cycle of the shaft and which further determines the actual location of each encoder line on the encoder in the rotational cycle of the shaft. By knowing the actual location of each encoder line and the number of counts between encoder lines for a given speed, a high accuracy encoder can be realized at a minimal cost.

Automatic encoder calibration

A piezoelectric bimorph scanner is disclosed which has a flexural beam attached to the free end of a cantilever mounted piezoelectric bimorph crystal. A mirror is bonded to the flexural beam a predetermined distance from the bimorph crystal. An AC voltage of predetermined frequency is applied to the bimorph crystal causing the flexural beam to oscillate with a node at the center of the mirror. The mirror rotates about the node rather than swinging in an arc, enabling the scanner to deflect a collimated light beam over a larger deflection angle than heretofore possible without additional light beam control apparatus. In an alternate embodiment, a laser diode may be mounted on the flexural beam instead of the mirror, further reducing costs and components.

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Yorktown Heights, NY, United States of America

Barry M Wolf