Motor controller, image processing apparatus including the motor controller, and motor control method

Patent metadata

Field	Value
Publication number	US-9367046-B2
Application number	US-201514706423-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	Aug 8, 2012
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A motor controller, operatively connected to a motor having an output shaft, includes a rotary detector to detect a rotation direction and a rotation amount of the output shaft of the motor to generate an actual rotary signal, a drive controller to generate a control signal based on the actual rotary signal and a target rotary signal indicating a target rotary direction and a target rotary amount, and a driver to supply a driving power to the motor based on the control signal. When the motor is in a hold state, the control signal is reversed periodically for a predetermined reverse time period T 2 per a predetermined one reverse cycle T 1 . When the control signal is not reversed for a certain lock detection time period Tr that is longer than the revere cycle T 1 of the control signal, supply of the driving power to the motor is blocked.

First claim

The invention claimed is:

1. A controller for outputting a control signal to a motor driver that supplies driving power to a motor, the motor driver blocking supply of the driving power to the motor when the control signal is not changed for a time equal to or longer than a predetermined lock detection time period, the controller comprising:
a motor drive controller to provide the control signal to the motor driver,
wherein, in a position hold state in which the motor is stopped to maintain a position of a rotor, a voltage of the control signal provided by the motor drive controller changes from a first control voltage to a second control voltage during a predetermined control-change time period shorter than an electrical time constant of the motor, the predetermined control-change time period occurring at a predetermined interval shorter than the lock detection time period.

2. The controller according to claim 1 , wherein the control-change time period is equal to or longer than a minimum detectable time period which is a minimum time period needed for the motor driver to detect a change in the control voltage.

3. The controller according to claim 1 , wherein, when a target position of the rotor is kept constant in the position hold state and a difference between the target position and a detected position of the rotor is smaller than a position error allowable range for a time period equal to or longer than a predetermined waiting time, the voltage of the control signal provided by the motor drive controller is changed.

4. A driving mechanism, comprising:
a motor;
an encoder disc attached to a rotary shaft of the motor;
a sensor to detect rotation of the encoder disc and output a rotary signal of the motor; and
the controller according to claim 1 .

5. The driving mechanism according to claim 4 , wherein the motor drive controller detects a position of the rotor based on the rotary signal.

6. The driving mechanism according to claim 4 , wherein the rotary signal includes two encoder pulses having a phase difference.

7. A transport apparatus, comprising:
the driving mechanism according to claim 4 ; and
a transport device to be driven by the driving mechanism.

8. An image processing apparatus, comprising:
the driving mechanism according to claim 4 ; and
a transport device to be driven by the driving mechanism.

9. A method of outputting a control signal to a motor driver that supplies driving power to a motor, the motor driver blocking supply of the driving power to the motor when the control signal is not changed for a time equal to or longer than a predetermined lock detection time period, the method comprising:
providing the control signal from a motor drive controller to the motor driver; and
changing a voltage of the control signal from a first control voltage to a second control voltage during a predetermined control-change time period shorter than an electrical time constant of the motor, the predetermined control-change time period occurring at a predetermined interval shorter than the lock detection time period, by the motor drive controller, when in a position hold state in which the motor is stopped to maintain a position of a rotor.

10. A non-transitory computer-readable recording medium storing a program, which, when executed, causes a controller to execute the method according to claim 9 .

Assignees

• Ricoh Co Ltd

Inventors

• Murata Takuya
• Ishizuka Natsuko

Classifications

• G05B6/02 Primary

  electric · CPC title

• G05B2219/2646

  Printing · CPC title

• H02P6/30

  Arrangements for controlling the direction of rotation (H02P6/22 takes precedence) · CPC title

• G03G15/6529

  Transporting (G03G15/6555 takes precedence) · CPC title

• G05B19/042 Primary

  using digital processors (G05B19/05 takes precedence) · CPC title