Abstract: 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.

Abstract: In a laser printer, methods and apparatus include commutating a brushless dc motor having three windings. A controller receives discrete motor position signals, such as from hall-effect or FG sensors, and extrapolates motor position between the signals. It commutates the motor based on the extrapolated motor position and updates motor position whenever an actual discrete signal is received. Drive signals from the controller to the motor are such that a current flowing in any of the three windings follows a generally sinusoidal waveform. High and low switches are provided per each winding of the three windings and are cumulatively switched according to an extrapolated motor position based multiplier applied to a pulse width modulation duty cycle. In this regard, lookup tables, counters, registers and the like are provided. An engine card of the printer includes an ASIC with a power driver for use with generally off-the-shelf brushless dc motors.

Abstract: The present invention is directed to an article, system and method for determining and/or selecting the location of a toner engaging member in a developing agent device such as a toner cartridge. The article, system and method may be applied to a printing device such as a laser printer.

Abstract: 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.

Abstract: 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.