# US 5,703,455 A · Control device for a stepping motor included in an electronic apparatus

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- Number: US 5,703,455 A
- Document ID: US5703455A
- Status: Granted
- Kind: A
- Application number: 08/707,073
- Filed: 1996-09-03
- Granted: 1997-12-30
- Earliest claimed: 1995-09-05
- Assignees: Ricoh Company, Ltd.
- Inventors: Hideto Miyazaki
- Web page: https://patentgrep.com/patent/US5703455A

## CPC

- H02P 8/14: Arrangements for controlling speed or speed and torque (H02P8/12, H02P8/22 take precedence)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

A control device for controlling the drive of a stepping motor included in an electronic apparatus as a drive source is disclosed. The stepping motor is totally controlled by a microprocessor and driven by a motor driver. A memory stores control data for the acceleration, constant-speed drive and deceleration of the motor. A motor controller controls the motor via the motor driver with the control data loaded without the intermediary of the microprocessor. A constant-speed rotation end signal is input to the motor controller from either a CPU (Central Processing Unit) or an external unit as a repeat signal. When the repeat signal is "0", the control data stored in the memory and assigned to constant-speed drive is repeatedly loaded a preselected number or times, causing the motor to rotate at a constant speed. When the repeat signal is "1", the above control data is repeatedly loaded until the repeat signal changes to "0".

## Claims

### Claim 1

A control device for controlling drive of a stepping motor which drives a movable portion of an electronic apparatus and is totally controlled by a microprocessor, said control device comprising:
motor drive means for driving the stepping motor;
store means for storing control data for acceleration, constant-speed drive and deceleration of the stepping motor; and
motor control means for controlling the stepping motor via said motor drive means with said control data loaded without the intermediary of the microprocessor;
said motor control means comprising:
first constant-speed rotation control means for repeatedly loading the control data assigned to the constant-speed drive a preselected number of times to thereby rotate the stepping motor at a constant speed;
second constant-speed rotation control means for repeatedly loading said control data assigned to the constant-speed drive until a constant-speed rotation end signal arrives to thereby rotate the stepping motor at the constant speed; and
constant-speed control selecting means for selecting one of said first and second constant-speed rotation control means at a time.

### Claim 2 (depends on 1)

A control device as claimed in claim 1, wherein said constant-speed rotation end signal is input from the microprocessor.

### Claim 3 (depends on 1)

A control device as claimed in claim 1, wherein said constant-speed rotation end signal is input from an external unit.

### Claim 4 (depends on 1)

A control device as claimed in claim 1, wherein said motor control means comprises signal selecting means for selecting said constant-speed rotation end signal output from one of the microprocessor and an external unit, and wherein said second constant-speed rotation control means repeatedly loads said control data assigned to the constant-speed drive until said constant-speed rotation end signal selected by said signal selecting means arrives.

### Claim 5 (depends on 1)

A control device as claimed in claim 1, wherein said motor control means forms a part of a control LSI installed in the electronic apparatus.

### Claim 6

An electronic apparatus including a movable portion, comprising:
a stepping motor for driving the movable portion; and
a control device for controlling drive of said stepping motor;
said control device comprising:
motor drive means for driving the stepping motor;
store means for storing control data for acceleration, constant-speed drive and deceleration of the stepping motor; and
motor control means for controlling the stepping motor via said motor drive means with said control data loaded without the intermediary of a microprocessor;
said motor control means comprising:
first constant-speed rotation control means for repeatedly loading the control data assigned to the constant-speed drive a preselected number of times to thereby rotate the stepping motor at a constant speed; and
second constant-speed rotation control means for repeatedly loading said control data assigned to the constant-speed drive until a constant-speed rotation end signal arrives to thereby rotate the stepping motor at the constant speed; and
constant-speed control selecting means for selecting one of said first and second constant-speed rotation control means at a time.