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Stepping motor control device and conveying device provided with the same

a technology of stepping motor and control device, which is applied in the direction of control system, dynamo-electric converter control, thin material processing, etc., can solve the problem of increasing the ripple current during acceleration, and the ripple current is reduced, so as to reduce the power loss of stepping motor driving and reduce the ripple current

Active Publication Date: 2015-09-15
SHARP KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009]Therefore, in view of the problems described above, it is desirable to provide a control device for a stepping motor that can reduce power loss of stepping motor driving IC and reduce the ripple current in stepping motor accelerating and decelerating periods without necessitating the conventional current switching circuit, and to provide a conveyer device provided with the control device.
[0015]The present invention enables reduction of power loss of the driving unit (driver IC) during the accelerating or decelerating period of rotation of the stepping motor, and reduction of ripple current. Further, during the accelerating or decelerating period of rotation of the stepping motor, the stepping motor can be controlled with the current value comparable to that in the constant-speed rotation period and, therefore, the conventional current switching circuit becomes unnecessary. Further, it is unnecessary to use a power source that can supply large peak current.

Problems solved by technology

In addition, there is a problem that ripples of driving current become larger during acceleration than in the steady state.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0032]An image processing apparatus including the stepping motor control device in accordance with the first embodiment of the present invention is a digital multifunction peripheral having a plurality of functions, including copy, facsimile, scanner and printer functions. Referring to FIG. 1, image processing apparatus 100 includes an automatic document feeder 114, a document reading unit 116, an image forming unit 118, an operation unit 124, a paper feed unit 130, and a paper discharge unit 132. Operation unit 124 includes a touch-panel display and an operation key portion (neither being shown). Operation unit 124 receives inputs such as instructions to image processing apparatus 100 by a user.

[0033]Referring to FIG. 2, image processing apparatus 100 includes a CPU (Central Processing Unit) 102 for overall control of image processing apparatus 100, an ROM (Read Only Memory) 104, an RAM (Random Access Memory) 106 and an HDD (Hard Disk Drive) 108. ROM 104 is a non-volatile storage d...

second embodiment

[0082]In the first embodiment, the stepping motor control device controls the stepping motor with the same PWM frequency both in the accelerating and decelerating periods. In the second embodiment, different PWM frequencies are used in the accelerating and decelerating periods.

[0083]The image processing apparatus in accordance with the present embodiment has the configurations shown in FIGS. 1 to 4, similar to the image processing apparatus in accordance with the first embodiment. The object of control of motor control unit 112 is the stepping motor included in automatic document feeder 114. Different from the first embodiment, in the present embodiment, a circuit shown in FIG. 11 is used in place of the circuit shown in FIG. 5, as the motor control unit 112.

[0084]Referring to FIG. 11, a frequency switching circuit 154 is a circuit for changing resistance value between the CR terminal and the ground. Frequency switching circuit 154 is formed by adding a circuit portion including a t...

third embodiment

[0097]In the stepping motor control device in accordance with the first and second embodiments, the stepping motor is subjected to open-loop control, and the end of accelerating period is determined by the number of steps (the number of CLK signal pulses) of the control signal. In the third embodiment, information related to the speed of rotation is fed-back from the stepping motor, and using this, the end of accelerating period is determined.

[0098]Similar to the image processing apparatus in accordance with the first embodiment, the image processing apparatus in accordance with the present embodiment has the configuration shown in FIGS. 1 to 3. In the present embodiment, different from FIG. 4 of the first embodiment, the stepping motor control device is structured as shown in FIG. 13. Motor control unit 112 is the same as that shown in FIG. 11, and the object of control of motor control unit 112 is the stepping motor included in automatic document feeder 114.

[0099]Referring to FIG....

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PUM

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Abstract

A stepping motor control device includes a driving IC driving a stepping motor by PWM control, and a setting circuit for setting PWM frequency of the driving IC. The setting circuit sets the driving IC such that in stepping motor accelerating and decelerating periods, the PWM frequency of the driving IC becomes higher than the PWM frequency of the driving IC in a constant-speed period of the stepping motor. Thus, power loss of the driving IC in the stepping motor accelerating and decelerating periods can be reduced, and ripple current can be reduced.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2013-245965 filed in Japan on Nov. 28, 2013, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a device for controlling a stepping motor used, for example, for conveying a sheet of recording paper in a copy machine. More specifically, the present invention relates to a control device for a stepping motor enabling reduction of power loss and reduction of ripple current of a stepping motor driving IC at the time of acceleration and deceleration without necessitating the conventional current switching circuit, as well as to a conveyer device provided with the control device.[0004]2. Description of the Background Art[0005]As one type of image processing apparatuses as electronic equipment, an MFP (MultiFunction Peripheral) has been know...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): H02P8/00H02P8/14B65H7/20H02P8/12H02P8/16H02P8/18H02P8/10
CPCB65H7/20H02P8/10H02P8/12H02P8/14H02P8/16H02P8/18
Inventor MASHIBA, TAMAKI
Owner SHARP KK