Lexmark International, Inc.

Danny Keith Chapman

Steven Michael Turney

Kevin Dean Schoedinger

John Parker Richey

Steven Wayne Parish

Thomas Austin Fields

Brian Anthony Reichert

Matthew Lowell McKay

Gregory Lawrence Ream

Douglas Anthony Able

Mark Andrew Omelchenko

Mark Stephen Underwood

Michael Todd Phillips

Marshall White

Richard Winston Thomas

Hassan Bahrami

Michael William Craig

Benjamin Kyle Shepherd

Matthew David Miles

David Herman Alverson

David Ross Cutts

Joon Won Ha

Brian Michael Jacobs

Richard M Boothe

A media picking device for an image forming apparatus having a sensing mechanism for detecting the leading and trailing edge of a sheet of media being picked from a media input tray. The device includes a pick mechanism for picking the top-most media sheet; and a sensing mechanism including a sensor and a flag positioned adjacent the pick tire and moveable between at least two positions, the flag having a first end contacting the surface of a picked sheet; the flag moving from a first position to a second position when the leading edge of the picked sheet passes by and moving from the second position to the first position when the trailing edge of the picked sheet passes by. The sensing mechanism providing an output signal corresponding to the movement of the flag. The sensor is one of a photointerrupter, a proximity sensor, a potentiometer, and a switch.

Apparatus for detecting media edges in a media input tray

An imaging apparatus including an image transfer device, a first motor, a redrive section and a duplexing section. The first motor is drivingly connected to the image transfer device. The reversible redrive section is downstream from the image transfer device, and the reversible redrive section includes a second motor. The duplexing section includes a third motor. The duplexing section is positioned to receive media from the redrive section. The first motor, the second motor and the third motor are each independently controlled.

Duplex architecture for an imaging apparatus

Correction of rotary encoder eccentricity in an image forming device having a motor controller using period and position pulse train feedback signals. A motor includes an encoder disc rotating with the motor and at least two encoder sensors disposed at different circumferential positions about the encoder disc. A controller may use a high speed clock to calculate a corrected speed count based on speed counts determined from the number of clock cycles that elapse per cycle of pulse trains from the encoders. The controller may also calculate a corrected position count based at least partly on one or more position counts determined from the number of clock cycles that elapse between periodic sampling points and transitions of encoder pulse trains. The corrected position count may also be calculated based on a position count and one or more speed counts.

Encoder eccentricity correction for motion control systems

An image forming apparatus includes a waste toner system that collects waste toner in a waste toner container. An amount of waste toner collected in the container is increased by using a driven toner distributing member that distributes accumulated toner within the container. The toner distributing member may be driven by a shared speed-controlled motor that further drives an image forming process member. The waste toner system may detect the accumulation of waste toner by monitoring a drive control circuit while the toner distributing member is being driven. For example, a logic circuit may detect the accumulation of waste toner based on monitoring a predetermined frequency of interest of a frequency domain transform of a motor control signal, the frequency of interest associated with the shared motor driving the toner distributing member.

Method and apparatus to detect loads associated with one of a plurality of components driven by a shared motor in an image forming apparatus

A method of controlling the speed and position of a motor includes receiving a pulse train indicative of the speed of the motor, and a periodic signal at a frequency greater than the pulse train. The number of cycles of the periodic signal per cycle of the pulse train is counted, and compared to a predetermined number. The speed of the motor is adjusted to match the count to the predetermined number, thus effecting speed control. A command position signal defining a plurality of sampling points is generated. The number of cycles of the periodic signal between a sampling point of the command position signal and an operative edge of the pulse train is counted and compared to a predetermined number. The speed of the motor is further adjusted to match the count to the predetermined number, thus effecting position control.

Motor speed and position control

A motor control circuit uses a stored commutation table to effect time-based commutation of a brushless dc motor. Each entry in the commutation table defines a motor winding commutation state, and an exemplary method of open-loop motor control based on the commutation table comprises commutating the motor based on sequentially selecting table entries at a desired selection rate. That is, motor speed is controlled precisely by controlling the sequential selection rate rather than by relying on feedback from the motor. However, motor feedback for closed-loop control may be used in some modes of operation. For example, the method may include closed-loop control or open-loop control depending on the motor speed range, and may transition from closed-loop to open-loop control.

Method and apparatus for time-based dc motor commutation

An improved variable speed fan controller for use in devices such as laser printers. The controller automatically adjusts its output signal to fans such that a fan quickly settles into an appropriate operating speed, even if the fan has been newly installed into the equipment. The controller can store values in non-volatile memory, if desired, to keep track of recent changes in the fan's operating parameters and corresponding control signal values. The controller is able to control relatively inexpensive fans that don't necessarily operate at a predictable fan rotating speed under repeatable conditions and control signals, by controlling the fan to an initial or predetermined rotating speed; if the fan isn't running within a suitable range of rotational speeds, then determining whether a fine or coarse adjustment should be made to the fan's rotational speed. The controller makes appropriate adjustments until the fan's rotational speed is within acceptable operating tolerances.

Method and apparatus for controlling a variable speed fan in an image forming device

In an electrophotographic print mechanism wherein one motor drives two or more removable toner cartridges, the presence of each cartridge is sensed and reported to the motor controller. If one or more cartridges are removed, such as for single-color printing, the motor control equation parameters are altered to compensate for the altered static torque load experienced by the motor. The parameters may be the proportional, integral, and/or derivative gains for one or more PID controllers.

Optimizing a printing motor under varying torque loads

Transfer belt subassembly for a color printer includes a transfer belt, home position indicator, temperature sensor, and memory. The transfer belt subassembly is measured and characterized after fabrication, before being installed in a printer. Measurement and calibration data for the transfer belt is stored in memory as part of the subassembly, including data representing velocity characteristics of the transfer belt and temperature compensation factors used by an engine-controller in a method to govern the speed of the drive motor. When the transfer belt subassembly is inserted into a printer, the engine-controller is operative in response to data stored in the memory and sensed belt velocity and temperature data, providing adjustment of belt velocity and compensation for variations in the transfer belt speed. Using the predetermined characterizing data, precise alignment of the color planes with respect to one another is achieved for accurate color printing.

Method and apparatus for controlling transfer belt velocity of a color printer

A motion control system for controlling the motion of an intermediate transfer member in an image forming apparatus is provided in which a measuring member directly contacts the intermediate transfer member and generates signals proportional to the surface motion of the member. The measured surface motion is provided as a feedback signal to a motor controller, which compares the feedback signal with a reference signal. The difference between the signals is used to adjust the control of the drive motor for the intermediate transfer member drive roller in order to maintain a constant velocity for the intermediate transfer member.

Intermediate transfer member motion control via surface wheel feedback

An improved printing apparatus provides for very accurate synchronization between cut sheet print media and the unfixed image which is conveyed on an Intermediate Transfer Member (ITM) such as a belt or a drum, and which is targeted for said print media. The printing apparatus is constructed as a single-pass ITM-based electrophotographic (e.g., laser) printer, and the length of the input print media pathway prior to image-to-media transfer is significantly shorter than the sum of the lengths of the image travel along a photoconductive drum and ITM. The print media is typically launched after imaging has been initiated on the photoconductive drum by an imaging apparatus. Variance in the leading edge of the print media with respect to the leading edge of image can be introduced due to phenomena such as pick errors, velocity variation, and uncertainties in the paper stack height. The present invention minimizes this leading edge variance to a tightly targeted specification by accurately sensing the positions of the print media and the ITM image, and correcting the print media's position by controlling the velocity of the print media prior to arriving at the transfer nip. In addition, the present invention detects the presence of print media within the sheet feeder cassette tray before imaging is started in the ITM belt, thereby minimizing the amount of waste toner generated by the printing apparatus. The imaging procedure on the ITM belt typically begins at a time prior to the printer controller having precise knowledge as to the location of the &ldquo;next&rdquo; sheet of print media within the combination of the input print media pathway and sheet feeder cassette tray.

Method and apparatus for controlling media-to-image registration of a single-pass intermediate transfer member-based printing apparatus

A method of minimizing error in an estimate of a position of a sheet of print medium in an electrophotographic machine includes providing a transport system including a gearing system to drive a roll for moving the sheet of print medium along a print medium path. The gears are in constant mesh with each other and with an actuator. The electrophotographic machine is provided with a toner transfer point at which the toner can be transferred to the moving sheet of print medium. A sensor is placed at a set distance away from the transfer nip along the print medium path. This distance is approximately equal to an integer multiple of the resulting distance traveled by the medium during one revolution of the lowest frequency component of the transport system. The frequencies associated with all other components in the transport system, including the actuator and an encoder wheel, are designed to be an integer multiple of this lowest frequency. The gearing system is actuated with a rotating actuator such that the actuator rotates approximately an integer number of times during a corresponding rotation of the lowest frequency component. An encoder wheel is also used to provide feedback to a control algorithm. A position of the sheet of print medium is sensed with the sensor.

Method and apparatus for minimizing the open loop paper positional error in a control system for an electrophotographic printing apparatus

A method of media-to-image registration sets a top writing line margin on a print medium within an electrophotographic machine. Movement of a substantially stationary sheet of print medium along a print medium path within the electrophotographic machine is initiated. An image associated with the sheet of print medium is scanned onto a developing unit. The scanning step commences before the initiating step. Toner is adhered to the image on the developing unit. The toner is transferred from the developing unit to a moving toner transfer medium. The electrophotographic machine is provided with a toner transfer area in which the toner can be transferred to the moving sheet of print medium. A speed of the movement of the sheet of print medium is adjusted such that the toner is transferred from the moving toner transfer medium to a desired area on the sheet of print medium within the toner transfer area. The sheet of print medium moves substantially continuously between the initiating step and a time of the transfer of the toner to the sheet of print medium.

Method and apparatus for positioning paper in an imaging system having an intermediate transfer medium

A method of controlling a speed of a print medium through a printer includes the step of providing a print medium transport assembly with a range of print medium transport speeds between a minimum print medium transport speed and a maximum print medium transport speed. A print engine is provided with a print engine speed. The range of print medium transport speeds is divided into subranges of print medium transport speeds. A requested speed is provided to the print medium transport assembly which corresponds to the print engine speed. For each subrange, an acceleration profile control equation, a constant speed control equation, and a deceleration profile control equation is determined. The constant speed control equation is dependent upon the requested speed. One of the subranges of print medium transport speeds is identified which encompasses the requested speed. The print medium is transported through the print medium transport assembly according to the acceleration profile control equation, the constant speed control equation, and the deceleration profile control equation associated with the selected subrange.

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Sadieville, KY, United States of America

Danny Keith Chapman