Motor control device, image forming apparatus, and motor control method

Patent metadata

Field	Value
Publication number	US-9318939-B2
Application number	US-201414245049-A
Country	US
Kind code	B2
Filing date	Apr 4, 2014
Priority date	Apr 16, 2013
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A motor control device performs drive control of a motor connected to an object. The motor control device includes a rotation detection unit that detects rotation of the motor and outputs a detection signal, a counter unit that receives the detection signal from the rotation detection unit and outputs a count based on the received detection signal, and an error detection unit that receives counts from the counter unit at intervals of a reference period, computes a difference between a present count received from the counter unit and a previously received count, and detects that an error arises in the rotation detection unit when the difference is continuously less than a reference value.

First claim

What is claimed is:

1. A motor control device which performs drive control of a motor connected to an object, comprising:
a rotation detection unit that detects rotation of the motor and outputs a detection signal;
a counter unit that receives the detection signal from the rotation detection unit and outputs a count based on the received detection signal; and
an error detection unit that receives counts from the counter unit at intervals of a reference period, computes a difference between a present count received from the counter unit and a previously received count, and detects that an error arises in the rotation detection unit when the difference is continuously less than a reference value.

2. The motor control device according to claim 1 , wherein the rotation detection unit comprises a rotary encoder that outputs two-phase pulses with different phase angles.

3. The motor control device according to claim 1 , wherein the counter unit increments the count during normal rotation of the motor and decrements the count during reverse rotation of the motor.

4. The motor control device according to claim 1 wherein the reference period is set based on a movement distance of the object driven by the motor.

5. The motor control device according to claim 1 wherein the reference value is set based on an expected movement distance of the object driven by the motor for the reference period.

6. An image forming apparatus comprising:
an image formation unit that forms an image; and
the motor control device according to claim 1 .

7. A motor control method performed by a motor control device which performs drive control of a motor and includes a rotation detection unit that detects rotation of the motor and outputs a detection signal, the method comprising:
receiving, by a counter unit, the detection signal from the rotation detection unit to output a count based on the received detection signal;
receiving, by an error detection unit, counts from the counter unit at intervals of a reference period;
computing, by the error detection unit, a difference between a present count received from the counter unit and a previously received count; and
detecting, by the error detection unit, that an error arises in the rotation detection unit when the difference is continuously less than a reference value.

8. A non-transitory computer-readable medium storing a program which when executed by a computer causes the computer to perform the motor control method according to claim 7 .

Assignees

• Watahiki Tatsuya
• Ishizuka Natsuko
• Ricoh Co Ltd

Inventors

• Watahiki Tatsuya
• Ishizuka Natsuko

Classifications

• H02P6/06

  Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed · CPC title

• G03G15/5004 Primary

  Power supply control, e.g. power-saving mode, automatic power turn-off · CPC title

• H02P31/00

  Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00 · CPC title

• G03G15/55

  Self-diagnostics; Malfunction or lifetime display · CPC title

• H02P6/17

  and for generating speed information · CPC title