JP4847108B2 - Motor drive control device and image forming apparatus - Google Patents

Description

  The present invention includes an encoder attached to a shaft of a rotating body that is rotated by a motor, and a sensor that detects a slit of the encoder, and drives and controls the motor so as to reduce fluctuations of the rotating body based on the output of the sensor. The present invention relates to a motor drive control device.

A motor drive control that includes an encoder attached to a shaft of a rotating body that is rotated by a motor and a sensor that detects a slit of the encoder, and that drives the motor to reduce fluctuations of the rotating body based on the output of the sensor. The apparatus is widely used for various devices.
For example, in an image forming apparatus such as a copying machine or a printer, a photosensitive member is rotationally driven by a stepping motor. An encoder is attached to the shaft of the photosensitive member, and a sensor is disposed opposite the encoder.
As a prior document, there is Patent Document 1 and the like.
JP 2004-101930 A

In the above image forming apparatus, when the photoconductor is replaced due to its life or failure, usually the work is performed by pulling out the photoconductor from the front of the apparatus and replacing it. At this time, the encoder and the main body attached to the shaft of the photoconductor There is a problem that the sensor fixed on the side interferes and the workability of the service person or the user is deteriorated.
The present invention relates to a motor drive control device that can easily pull out a rotating body from a main body by facing the encoder and a sensor at a position where they do not interfere with each other when the rotating operation of the motor is stopped (and hence when the rotating body stops rotating). The purpose is to provide.

In order to achieve the above object, the first means comprises: a rotating body that is rotated by a motor and has a different weight at a radially opposed position; an encoder that is attached to a shaft of the rotating body and provided with a notch ; based on the rotation of the encoder, a sensor which outputs a signal, and a control means for driving and controlling the pre SL motor based on an output of said sensor, said weight of the rotating body is different opposing positions, the encoder as notches of matches, the encoder is mounted, during the rotation stop of the operation of the rotating body, and the notch portion and the sensor is characterized and Turkey stops so as to face.
In this case, it is preferable that the shaft of the rotating body is locked when the rotating body is removed.
Further, the second means is characterized by an image forming apparatus equipped with the motor drive control device according to the first means .

  According to the present invention, since the encoder and the sensor can be stopped at a position where they do not interfere with each other when the rotating operation of the rotating body is stopped, the rotating body can be easily pulled out from the main body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a main part configuration diagram of an image forming apparatus in which a motor drive control device of the present invention is mounted. The configuration will be described together with the operation. When the motor 1 is driven, the photoconductor 4 is driven through the motor drive gear 2 and the photoconductor side driven gear 3. An encoder 6 is mounted on the drive shaft 5 of the photosensitive member 4, and speed variation data is detected by a transmission type sensor 7. Reference numeral 8 denotes an intermediate transfer belt that is in contact with the four photoconductors 4.
FIG. 2 is a diagram showing an example of an encoder used in the motor drive control device of the present invention. The encoder 6 used in the motor drive control device of the present invention has a pair of notches 6-1 and 6-2 at the target position. In the present invention, the notches 6-1 and 6-2 and the sensor 7 face each other when the rotation of the motor 1 is stopped, so that the encoder 6 and the sensor 7 do not interfere when the photosensitive member is replaced. .
FIG. 3 is a waveform diagram by the slit of the encoder detected by the sensor. A stepping motor is used as the motor 1. In the case of constant speed, the waveform is as shown in FIG. At this time, the time during which the sensor 7 is opened, that is, the time during which there is no obstruction between the light emitting part and the light receiving part is measured, and it is determined that it has been half of the notches 6-1 and 6-2. What is necessary is just to control a motor so that it may stop in the position used as a period or 1 period.
As an example, assuming that the number of teeth of the motor drive gear is 20, the number of teeth of the photoreceptor driven gear is 400, and the step angle of the stepping motor is 1.8 °, one round of the motor 1 is 1.8 ° × 200 = 360 °. Is 200 pulses and the photosensitive member half circumference is 10 motor cycles, so 200 × 10 = 2000 pulses, and the photosensitive member 4 rotations is 200 × 20 and 4000 pulses, so half of the time t1 is detected from 2000, 4000, 6000, 8000 pulses, etc. The motor 1 is controlled so as to stop at a position that becomes a cycle or one cycle. If the original speed stops and the speed does not step out, it may be stopped immediately after the time t1 is detected. Further, a brushless motor capable of position control may be used to perform control that stops in half a cycle or one cycle from the detection of time t1.

FIG. 4 is a diagram illustrating a state in which the encoder and the sensor face each other at a position where they do not interfere with each other. In addition to the control as described above, the encoder 6 and the sensor 7 face each other at a position where the weight of the photoconductor 4 does not interfere with each other.
The photosensitive member 4 is lightened diagonally to the extent that it does not affect the surface speed of the photosensitive member, the one side is heavy, and the notched portions 6-1 and 6-2 of the encoder 6 are made to coincide with the heavy side and the lightened side. In this way, whenever the motor 1 is stopped inertially when the motor is stopped, the photoconductor 4 can be stopped with the heavy side down and the light side up. With this weight arrangement, the encoder 6 and the sensor 7 can face each other at a position where they do not interfere with each other.
FIG. 5 is a perspective view of the photosensitive member and the photosensitive member-side driven gear portion in a state where the rotation restricting piece is attached to the drive shaft, and FIG. 6 is a diagram illustrating a first example of the drive shaft rotation restricting mechanism. The drive shaft 5 is provided with a rotation restricting piece 11 extending horizontally on both sides of the drive shaft 5, and the restricting piece abutting member 12 is lowered when the motor 1 is turned off as shown in FIG. Then, it comes into contact with the rotation restricting piece 11, and as shown in FIG. 6B, when the motor 1 is turned on, the restricting piece abutting member 12 rises and separates from the rotation restricting piece 11.
With such a configuration, the drive shaft 5 is prevented from rotating while the motor 1 is stopped at a position where the photosensitive member 4 can be attached and detached, that is, a position where the encoder 6 and the sensor 7 do not interfere with each other. At this time, the drive shaft 5 and the drive shaft insertion holes of the photoconductor 4 and the encoder 6 are cut into a D shape, so that when the photoconductor 4 and the encoder 6 are removed from the main body and reinserted, the cutout portion of the encoder 6 is obtained. The positions 6-1 and 6-2 can be inserted only at positions where they do not interfere with the sensor 7.

FIG. 7 is a view showing a second example of the drive shaft rotation restricting mechanism. A hole is provided in the drive shaft 5, and the motor 1 or solenoid is moved by the motor 1 or solenoid so that the rotation restricting shaft 13 passes through the hole when the photosensitive member 4 is stopped, that is, the motor 1 or solenoid is pulled out of the hole when the motor is on. By operating, it is possible to prevent the drive shaft 5 from rotating.
FIG. 8 is a circuit configuration diagram for driving the motor to a position where the encoder and sensor do not interfere with each other when the power is shut off, and FIG. 9 is an operation flowchart of the circuit of FIG.
In the circuit shown in FIG. 8, a main control unit 21, a power source 22, and a backup power source 23 are provided, and the power source can be switched by a relay 24.
As shown in FIG. 9, when the power source 22 is turned off (S1), the operation of such a circuit is connected to the backup power source 23 side by switching the relay 24 and supplies power only to the motor 1 and the sensor 7. (S2). The motor 1 is continuously driven (S3), and the encoder 6 is moved to a position where the notches 6-1 and 6-2 of the encoder 6 and the sensor 7 face each other (S4).
Whether or not the encoder 6 has reached a position where it does not interfere with the sensor 7 is confirmed by checking the input signal of the sensor 7 and the position where the sensor 7 is opened for a certain period of time is the position of the notches 6-1 and 6-2. Therefore, the motor 1 is stopped at the position, or the motor 1 is stopped at a position that is a half cycle or one cycle from the position (S5).
When the movement of the encoder 6 is thus completed, the backup power source 23 is turned off (S6). By doing so, the motor 1 (the drive shaft 5 of the photoconductor 4) stops at a position where the encoder 6 and the sensor 7 interfere due to a sudden power off during rotation, and the photoconductor 4 is pulled out from the main body as it is. The encoder 6 and sensor 7 can be prevented from being damaged.

It is a principal part block diagram of the image forming apparatus by which the motor drive control apparatus of this invention is mounted. It is a figure which shows an example of the encoder used for the motor drive control apparatus of this invention. It is a wave form diagram by the slit of the encoder detected by a sensor. It is a figure which shows a mode that the encoder and the sensor are confronting in the position which does not interfere. FIG. 4 is a perspective view of a photoconductor and a photoconductor side driven gear portion showing a state where a rotation regulating piece is attached to a drive shaft. It is a figure which shows the 1st example of a drive shaft rotation control mechanism. It is a figure which shows the 2nd example of a drive shaft rotation control mechanism. It is a circuit block diagram which drives a motor to the position where an encoder and a sensor do not interfere at the time of power-off. FIG. 9 is an operation flowchart of the circuit of FIG. 8.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Motor, 2 Motor drive gear, 3 Photoconductor side driven gear, 4 Photoconductor, 5 Drive shaft, 6 Encoder, 6-1, 6-2 Notch part, 7 Sensor

Claims (3)

A rotating body that is rotated by a motor and has different weights at opposite positions in the radial direction ;
An encoder attached to the shaft of the rotating body and provided with a notch ;
A sensor that outputs a signal based on rotation of the encoder;
And control means for driving and controlling the pre SL motor based on an output of said sensor,
With
The encoder is attached so that the facing position where the weight of the rotating body differs and the notch portion of the encoder match, and when the rotation operation of the rotating body stops, the notch portion and the sensor face each other. The motor drive control device is characterized in that it stops as described above . The motor control device according to claim 1,
A motor drive control device configured to lock the shaft of the rotating body when the rotating body is removed . An image forming apparatus comprising the motor drive control device according to claim 1 .

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