Method and apparatus for moving a medium through a medium indexing device
AssigneeXerox Corporation
InventorRoger Guy Markham
Life of this patent
Estimating the term…
Abstract
A method and an apparatus for a medium indexing device, such as an ink jet printer, that includes utilizing greater torque generated by a motor at lower speed and lower torque available by the motor at higher speeds. Motion profiling during acceleration and deceleration is designed to better utilize available torque provided by the motor in order to quickly position the medium during start-stop operations and to reduce the maximum power or speed required of the motor during the indexing operations. The motor may include a stepper or servo motor, and may apply to medium indexing devices other than printers. In addition, a velocity discontinuity in motor speed is provided near the stop position to prevent the medium from overshooting the intended stop position.
Claims25
A method for operating an electric motor of a medium indexing mechanism requiring start-stop motion of a medium, the method comprising:
- accelerating the motor at an above average acceleration rate until motor speed reaches at least one-quarter peak speed to maximize torque usage at lower motor speeds;
- subsequently reducing acceleration of the motor until said peak speed is reached to lessen torque requirements and motor current demand at higher motor speeds;
- decelerating the motor at a below average rate from the peak speed to at least three quarter peak speed;
- subsequently decelerating the motor at an above average deceleration rate until reaching near an intended stopping position;
- and
- commanding a zero speed-hold position in which the motor stops at the intended stopping position.
A method of positioning a piece of paper along a transport path of a printer, said method comprising:
- placing said sheet of paper at an entrance to said printer;
- driving a motor of said printer by accelerating the motor at an above average acceleration rate until motor speed reaches at least one-quarter peak speed to maximize torque usage at lower motor speeds;
- subsequently reducing acceleration of the motor until said peak speed is reached to lessen torque requirements and motor current demand at higher motor speeds;
- decelerating the motor at a below average rate from the peak speed to at least three-quarter peak speed;
- subsequently decelerating the motor at an above average deceleration rate until reaching near an intended stopping position;
- and
- commanding a zero speed-hold position in which the motor stops and positions said paper at an optimum position for printing.
An apparatus for controlling positioning of a medium in a medium indexing device, said apparatus comprising:
- a plurality of gears and rollers operably provided to engage and index a medium;
- a motor for driving said gears and rollers;
- and
- a processor adapted to control said motor so as to utilize more motor torque at lower motor speeds and less torque at higher motor speeds by:
- accelerating the motor at an above average acceleration rate until motor speed reaches at least one-quarter peak speed to maximize torque usage at lower motor speeds;
- subsequently reducing acceleration of the motor until said peak speed is reached to lessen torque requirements and motor current demand at higher motor speeds;
- decelerating the motor at a below average rate from the peak speed to at least three-quarter peak speed;
- subsequently decelerating the motor at an above average deceleration rate until reaching near an intended stopping position;
- and
- commanding a zero speed-hold position in which the motor stops at the intended stopping position.
Dependencies are inferred from the claim text.