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: 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: The present application is directed to methods and devices for controlling a motor in an image forming device by sensing the amount of current applied to the motor. One embodiment includes a power supply operatively connected to a controller. The power supply provides an electrical current to a motor, and the amount of current is measured. The controller monitors the amount of current and determines an operating condition of the motor based on the current. The controller may then continue to allow the power supply to provide the electrical current to the motor, or may shut off the current based on the operating condition. The controller may also monitor a timer to determine how long the power supply has provided current to the motor. In one embodiment, the controller may use both the signal and monitored time to determine the operating condition of the motor.

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.

Abstract: A method of storing usage information in an ink jet printer includes storing low priority usage information in a first memory field. First high priority usage information is stored in a second memory field. Second high priority usage information is stored in a third memory field. The second high priority usage information is substantially identical to the first high priority usage information.

Abstract: A thermal ink jet printing apparatus maintains stable printing output as certain characteristics of the apparatus change over its operational lifetime. The apparatus includes an ink jet print head with resistive heating elements for receiving electrical energy pulses having a voltage level and for transferring heat energy pulses having a desired energy level into adjacent ink based on the electrical energy pulses. The print head includes nozzles associated with the resistive heating elements through which droplets of the ink are ejected when the heat energy pulses are transferred into the ink. The apparatus further includes a printer controller in electrical communication with the print head.

Abstract: A method of storing usage information in an ink jet printer includes storing low priority usage information in a first memory field. First high priority usage information is stored in a second memory field. Second high priority usage information is stored in a third memory field. The second high priority usage information is substantially identical to the first high priority usage information.

Abstract: A thermal ink jet printing apparatus maintains stable printing output as certain characteristics of the apparatus change over its operational lifetime. The apparatus includes an ink jet print head with resistive heating elements for receiving electrical energy pulses having a voltage level and for transferring heat energy pulses having a desired energy level into adjacent ink based on the electrical energy pulses. The print head includes nozzles associated with the resistive heating elements through which droplets of the ink are ejected when the heat energy pulses are transferred into the ink. The apparatus further includes a printer controller in electrical communication with the print head.

Abstract: A print system includes a printer having a printer controller. One or more optional support devices are associated with the printer, wherein each optional support device includes a device controller. The system further includes a bi-directional serial communications path, including one or more trunklines, which provides serial electrical interconnection between the printer controller and each device controller of each optional support device of the system. The printer controller automatically assigns a unique device address to each optional support device. Transmission error detection system and method are provided at the printer controller and/or each optional support device.