An image forming apparatus and an image forming method are provided. The image forming apparatus includes a printing engine to form an image, a step motor to drive the printing engine, a driving circuit to provide a constant current to the step motor and sense a voltage corresponding to a magnitude of the constant current provided to the step motor, and a processor to calculate a temperature of the step motor based on the voltage sensed by the driving circuit during an excitation period of the step motor and control an operation of the image forming apparatus based on the calculated temperature.

A back electromagnetic force detection circuit detects a counter EMF generated in a coil of a stepping motor. A revolution count detection circuit generates a revolution count detection signal. A determining circuit generates a determination signal that is asserted if the revolution count detection signal is stable across multiple consecutive cycles. A current value setting circuit generates a current setting value indicating a target value of a coil current. The current value setting circuit sets the current setting value to a predetermined value in a period in which the determination signal is negated, and adjusts the current setting value according to the counter EMF in a period in which the determination signal is asserted. A constant current chopper circuit generates a pulse modulation signal that modulates by way of having a detection value of a coil current approach close to a target value of the current setting value.

A back electromagnetic force detection circuit detects a counter EMF generated in a coil of a stepping motor. A revolution count detection circuit generates a revolution count detection signal. A determining circuit generates a determination signal that is asserted if the revolution count detection signal is stable across multiple consecutive cycles. A current value setting circuit generates a current setting value indicating a target value of a coil current. The current value setting circuit sets the current setting value to a predetermined value in a period in which the determination signal is negated, and adjusts the current setting value according to the counter EMF in a period in which the determination signal is asserted. A constant current chopper circuit generates a pulse modulation signal that modulates by way of having a detection value of a coil current approach close to a target value of the current setting value.

In accordance with at least one example of the description, a circuit is adapted to be coupled to a coil of a motor via an H-bridge circuit. The circuit includes a duty sensor, a subtractor, and a comparator. The duty sensor is coupled to the coil of the motor and is configured to provide raw run duty data responsive to a coil current through the coil. The subtractor is coupled to the duty sensor and is configured to provide a differential duty signal responsive to a stall duty signal and a run duty signal obtained using the raw run duty data. The comparator is coupled to the subtractor and is configured to provide a stall signal indicative of a stall condition for the motor responsive to the differential duty signal and a threshold value.

In accordance with at least one example of the description, a circuit is adapted to be coupled to a coil of a motor via an H-bridge circuit. The circuit includes a duty sensor, a subtractor, and a comparator. The duty sensor is coupled to the coil of the motor and is configured to provide raw run duty data responsive to a coil current through the coil. The subtractor is coupled to the duty sensor and is configured to provide a differential duty signal responsive to a stall duty signal and a run duty signal obtained using the raw run duty data. The comparator is coupled to the subtractor and is configured to provide a stall signal indicative of a stall condition for the motor responsive to the differential duty signal and a threshold value.

A closed-loop stepper motor control system, drive device and automation device, wherein the system comprises a microprocessor (1) compatible with EtherCAT communication protocol functions, an external interface circuit (2) connected to the said microprocessor (1) and communication interface unit (3); the said microprocessor (1) is also connected to a drive circuit (4), current testing circuit (5), as well as an encoder feedback circuit (6); the said communication interface unit (3) is mutually connected to the said microprocessor (1) through the physical layer communication circuit (31); the said microprocessor (1) is also mutually connected to the power supply circuit (7) that provides stable power supply voltage.

A closed-loop stepper motor control system, drive device and automation device, wherein the system comprises a microprocessor (1) compatible with EtherCAT communication protocol functions, an external interface circuit (2) connected to the said microprocessor (1) and communication interface unit (3); the said microprocessor (1) is also connected to a drive circuit (4), current testing circuit (5), as well as an encoder feedback circuit (6); the said communication interface unit (3) is mutually connected to the said microprocessor (1) through the physical layer communication circuit (31); the said microprocessor (1) is also mutually connected to the power supply circuit (7) that provides stable power supply voltage.

The application includes a rotating device 1 that includes a variable resistor, a voltage output line configured to output a voltage, and an adjustment resistor. A resistance value Rx of the adjustment resistor is set to a value between a minimum value RxMin determined in a manner for a ratio of an adjustment voltage Vx in a case of having the adjustment resistor to a reference voltage Vo in a case of not having the adjustment resistor to become greater than or equal to a predetermined value, and a maximum value RxMax determined in a manner for noise generated on the voltage output from the voltage output line with the contact position located within a dead zone of a position sensor 80 to become less than or equal to a predetermined value.

A closed-loop stepper motor control system, drive device and automation device, wherein the system comprises a microprocessor (1) compatible with EtherCAT communication protocol functions, an external interface circuit (2) connected to the said microprocessor (1) and communication interface unit (3); the said microprocessor (1) is also connected to a drive circuit (4), current testing circuit (5), as well as an encoder feedback circuit (6); the said communication interface unit (3) is mutually connected to the said microprocessor (1) through the physical layer communication circuit (31); the said microprocessor (1) is also mutually connected to the power supply circuit (7) that provides stable power supply voltage.

A closed-loop stepper motor control system, drive device and automation device, wherein the system comprises a microprocessor (1) compatible with EtherCAT communication protocol functions, an external interface circuit (2) connected to the said microprocessor (1) and communication interface unit (3); the said microprocessor (1) is also connected to a drive circuit (4), current testing circuit (5), as well as an encoder feedback circuit (6); the said communication interface unit (3) is mutually connected to the said microprocessor (1) through the physical layer communication circuit (31); the said microprocessor (1) is also mutually connected to the power supply circuit (7) that provides stable power supply voltage.