Motor connection detecting device, motor connection detecting method, image forming device, and conveyance device

1. A motor connection detecting device comprising:

a bipolar stepping motor;

a motor driver configured to control current to be supplied to the bipolar stepping motor; and

a controller connected to the bipolar stepping motor and the motor driver, the controller configured to,

detect voltage of regenerative current generated during motor ON time in which current flows in the bipolar stepping motor, the voltage being generated during a fast decay period according to a current attenuation method of the regenerative current, and

determine a presence of an abnormal connection between motor winding wires of the bipolar stepping motor and terminals of the motor driver based on the voltage.

2. The motor connection detecting device according to claim 1 , wherein the controller is configured to detect the voltage when the bipolar stepping motor is set in an excitation holding state.

3. The motor connection detecting device according to claim 2 , wherein

the motor driver is configured to perform chopping control drive for the bipolar stepping motor, and

the controller is configured to detect the voltage at timing of the fast decay period which represents an OFF period during the chopping control drive performed by the motor driver.

4. The motor connection detecting device according to claim 1 , wherein

the controller is configured to generate a control command to control an amount of the current by the motor driver.

5. An image forming device comprising:

the motor connection detecting device according to claim 4 ,

wherein the bipolar stepping motor is applied to at least one of a DC motor configured to drive a conveyance roller and a drum drive motor configured to rotationally drive a drum.

6. A conveyance device comprising:

the motor connection detecting device according to claim 4 ,

wherein the bipolar stepping motor is applied to a motor configured to drive a conveyance roller.

7. The motor connection detecting device according to claim 1 , wherein the controller is configured to determine the presence of the abnormal connection based on the voltage during an excitation holding state such that the voltage is measured only when current flows through the motor driver via a first one of a pair of current paths associated with the motor driver.

8. The motor connection detecting device according to claim 7 , wherein the controller is configured to determine the presence of the abnormal connection by cancelling an offset error between a first current value in a period prior to the excitation holding state and a second current value in a period after the excitation holding state.

9. A motor connection detecting method comprising:

controlling current supplied to a bipolar stepping motor by a motor driver;

detecting, by a controller connected between the bipolar stepping motor and the motor driver, voltage of regenerative current generated during a motor ON time in which current flows in the bipolar stepping motor, the voltage being a voltage generated during a fast decay period according to a current attenuation method of the regenerative current; and

determining, by the controller, a presence of an abnormal connection between motor winding wires of the bipolar stepping motor and terminals of the motor driver based on the voltage detected in the detecting.

10. The motor connection detecting method according to claim 9 , wherein

in the detecting, the voltage is detected when the bipolar stepping motor is set in an excitation holding state.

11. The motor connection detecting method according to claim 10 , wherein

in the controlling, chopping control drive is performed for the bipolar stepping motor, and

in the detecting, the voltage is detected at timing of the fast decay period which represents an OFF period during the chopping control drive performed in controlling the current.

12. The motor connection detecting method according to claim 9 , wherein the determining determines the presence of the abnormal connection based on the voltage during an excitation holding state such that the voltage is measured only when current flows through the motor driver via a first one of a pair of current paths associated with the motor driver.

13. The motor connection detecting method according to claim 12 , wherein the determining determines the presence of the abnormal connection by cancelling an offset error between a first current value in a period prior to the excitation holding state and a second current value in a period after the excitation holding state.