JPH06153561A - Circuit for detecting abnormality in motor - Google Patents

Abstract

PURPOSE:To make it possible to promptly and properly cope with an abnormality in a motor by minutely the cause of the abnormality. CONSTITUTION:If a motor 36 does not rotate, CPU 37 determines, based on signals fed to an input terminal A, whether the abnormality is caused by any trouble in the motor 36 itself or that in transistors 33 and 34, motor drive elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor abnormality detection circuit capable of subdividing causes of motor abnormality.

[0002]

2. Description of the Related Art Many electronic devices and control devices use a motor. However, if the circuit for driving the motor has an abnormality, the motor does not rotate and cannot operate normally.
For example, in an electrophotographic copying machine (hereinafter referred to as a copying machine), if there is an abnormality in the circuit that drives the motor for conveying the copying paper, the copying paper will not be conveyed.

Conventionally, whether or not the motor rotates can be easily known from the output of the encoder attached to the rotary shaft of the motor. As a result, even if it is found that the motor does not rotate, the cause thereof cannot be known, and therefore, simply. The error is displayed.

In the case of a copying machine, a user requests a serviceman to repair when an error message is displayed. However, since the serviceman cannot identify which part is abnormal only by this error message, a motor including a motor drive element is used. A method is adopted in which a large number of replacement parts such as the drive board or the motor are brought to the site, and parts that are considered to be abnormal are replaced with new parts one after another.

[0005]

However, this repair work is largely dependent on the experience and intuition of a service person, and it is difficult for an inexperienced service person to take time and it takes time.
There is also a lot of wasted parts.

The present invention has been made in view of the above points, and when the motor does not rotate, it is determined whether the cause is the failure of the motor itself or the abnormality of the motor drive element, and the abnormality is detected. The purpose is to respond promptly and accurately.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is to connect an energizing circuit to a motor, and to connect the energizing circuit to the power source side of the energizing circuit to turn on / off the energizing of the motor.
The energization switching means for turning off, the voltage detection means for detecting the voltage between the energization switching means of the energization circuit and the motor, the ON / OFF state of energization by the energization switching means, and the output of the voltage detection means An abnormality detecting circuit for the motor is constituted by an abnormality determining means for determining whether the abnormality is the abnormality of the motor drive board.

[0008]

According to the present invention, when the motor does not rotate despite the energization of the motor being turned on by the energization switching means, the abnormality determination means causes the failure of the motor based on the output of the voltage detection means. It is possible to determine whether the cause or the cause is an abnormality of the motor drive element.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic structure of a copying machine to which the motor abnormality detection circuit according to the present invention is applied.

A control panel 10 provided on the upper surface of the main body of the copying machine.
When a copy start instruction is given after the power button on 0 is turned on, the original 21 placed on the original table 1 is illuminated by the illumination lamp 2 and the reflected light 20 from the original 21 (indicated by a chain line). Is reflected by the first mirror 3, the second mirror 4, and the third mirror 5, is reflected by the fourth mirror 7 through the lens 6, and is projected onto the photoconductor drum 8. Form a latent image. Around the drum 8, a charging electrode 9 provided on the surface of the drum 8 for uniformly charging the photoconductor, and an electrostatic latent image formed on the photoconductor are developed to form a visible image (toner). Image forming device, a transfer device 13 for transferring the visible image from a paper feed cassette 11 to a copy paper 12 fed through a path indicated by a chain double-dashed line,
A separation electrode 14 for separating the copy paper 12 on which the visible image is transferred from the drum 8, a charge eliminating electrode 15 for eliminating the electric charge remaining on the photoconductor, and a toner remaining on the photoconductor after the charge elimination are performed. Cleaning devices 16 for removal are arranged respectively.

After the transfer, the copy paper 12 separated from the drum 8 through the path indicated by the chain double-dashed line is conveyed by the conveying roller 17 to the fixing device 18, where the toner on the copy paper 12 is heat-melted and the copy paper 12 is transferred. The sheet is fixed on the sheet and is ejected to the sheet ejection tray 19.

In such a copying machine, the motor abnormality detection circuit according to the present invention detects abnormality of the motor for moving the optical scanning system including the illumination lamp 2 and the motor for rotating the photosensitive drum 8, for example. Applied to.

Next, FIG. 1 shows an electrical connection diagram of an example in which the motor abnormality detection circuit according to the present invention is applied to the motor abnormality detection for rotating the photosensitive drum 8 shown in FIG.

Reference numeral 31 is a DC power source for driving the motor, and for example, a power source of about 30 [V] is used. DC power supply 3
A transistor 33, which functions as a motor driving switch, is connected between 1 and the motor 36. The base terminal of the transistor 33 is connected to the transistor 3 via the resistor r2.
4 and the base terminal of the transistor 34 is connected to the CPU 37. Where resistance r
The value 2 is about 2 [kΩ]. When the transistor 33 is turned on, the DC power supply 31 causes the motor 36
It is energized and rotates. In this embodiment, the transistor 3
3, 34 correspond to the motor drive elements.

The base terminal of the transistor 35 has a resistor r.
Point C between transistor 33 and motor 36 via
And the collector terminal of the transistor 35 is the CPU
Connected to 37. Here, the resistor r3 has a large resistance value (for example, 500 [k] for reducing the current flowing from the DC power supply 31 to the transistor 33, the point C, the resistor r3, the emitter terminal of the transistor 35, and the ground.
Ω]) is used. The DC power supply 32 is, for example, of 5 [V] and is connected to the collector terminal of the transistor 35 at a point B via the resistor r1.

When the CPU 37 outputs a HIGH signal to the base terminal of the transistor 34, the transistor 34 turns off.
The N state is set, which turns off the transistor 33. As a result, the DC power supply 31 does not energize the motor 36, and the motor 36 does not rotate. At this time, the voltage at the point C becomes 0 [V], and the transistor 35 is turned off. Therefore, the DC power source 3 is connected to the input terminal A of the CPU 37.
The voltage of 2 is applied as is via point B.

On the other hand, when the CPU 37 outputs a LOW signal to the base terminal of the transistor 34, the transistor 34
Is turned off, and the transistor 33 is turned on. As a result, the DC power supply 31 energizes the motor 36 to rotate the motor 36. At this time, the voltage at the point C becomes equal to the voltage of the DC power supply 31 (for example, 30 [V]),
The transistor 35 is turned on. Therefore, a current flows from the DC power supply 32 to the ground via r1, point B, and the transistor 35. Therefore, the voltage at the point B is 0 [V].
Therefore, the input terminal A of the CPU 37 becomes the ground potential.

Meanwhile, in the CPU 37, the motor 36 for rotating the photosensitive drum 8 shown in FIG. 2 outputs a LOW signal from the CPU 37 to the base terminal of the transistor 34 during the copying operation of the copying machine. Nevertheless, if no rotation is detected by the encoder (not shown), the signal to the input terminal A is checked.

When the potential of the input terminal A is HIGH, the voltage at the point C is 0 [V], so that the cause of the motor 36 not rotating is the transistor 33 or 34.
Is not in the ON state, that is, the drive element has failed.

On the other hand, when the potential of the input terminal A of the CPU 37 is 0 [V], the voltage is applied to the point C, so the transistors 33 and 34 are normal and the motor 36 rotates. The cause of the failure is the failure of the motor 36.

As described above, according to the present invention, the motor 36 is checked by checking the potential of the input terminal A of the CPU 37.
It is possible to determine whether the cause of the non-rotation of the motor is the drive element of the motor, that is, the transistor 33 or 34, or the motor 36 itself.

In the present embodiment, the transistors 33 and 34 are motor drive elements (motor drive switches), but the present invention is not limited to this, and is also applicable to the case where a relay or the like is a motor drive element. it can.

Further, the motor abnormality detection circuit according to the present invention can be applied not only to the motor of the copying machine but also to the motors used in various devices.

[0025]

As described above, according to the present invention,
When the motor does not rotate, it is possible to determine whether the cause is a motor failure or an abnormality in the motor drive element.If the cause of the abnormality is displayed, the user will be notified of the cause of the abnormality. As a result, the repair can be performed accurately and promptly, the time required for the repair can be greatly shortened, and the waste of replacement parts can be eliminated.

[Brief description of drawings]

FIG. 1 is an electrical connection diagram of an embodiment of a motor abnormality detection circuit according to the present invention.

FIG. 2 is a schematic configuration diagram of a copying machine to which a motor abnormality detection circuit according to the present invention is applied.

[Explanation of symbols]

 31 DC power supply 32 DC power supply 33 Transistor 34 Transistor 35 Transistor 36 Motor 37 CPU r1 resistance r2 resistance r3 resistance

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Etsuichi Maekawa 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company

Claims (1)

[Claims] 1. An energization circuit for a motor, energization switching means connected to a power source side of the energization circuit with respect to the motor to turn on / off energization to the motor, the energization switching means for the energization circuit, and the energization switching means. Voltage detection means for detecting voltage between the motor and ON / OF of energization by the energization switching means
An abnormality detection circuit for a motor, comprising: abnormality determination means for determining whether the motor is abnormal or the motor drive board is abnormal based on the state of F and the output of the voltage detection means.