JPH10333387A - Image carrier rotary driving mechanism for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image carrier rotary driving mechanism for image forming device capable of rotary driving the image carrier with excellent accuracy. SOLUTION: In this image carrier rotary driving mechanism for the image forming device capable of rotary driving the image carrier 101a by a rotary driving motor MC1 by connecting a shaft section of the image carrier 101a disposed in a line or plural lines and a motor shaft (driving shaft section) 11 of the rotary driving motor MC1 by the deflection shaft joint (binding member) CP, an encoder EC is provided on the shaft section of the flange BS1 attached on the shaft of the image carrier 101a, and at least, one unit of the encoder signal detecting unit ED1 is provided on a periphery of the encoder EC. Since the encoder EC is directly equipped on the shaft attached flange BS1 being integrally rotated with the image carrier 101a, the rotary speed change of the image carrier 101a is directly reflected to the encoder EC, the signal based thereon can be applied as the controlling signal, and the image carrier 101a can be rotary driven with the excellent accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drive mechanism for image carriers arranged in one or more rows in an image forming apparatus employing an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus employing an electrophotographic system, image carriers, which are electrophotographic photosensitive members having a photoconductive layer, are arranged in one or more rows. FIG. 6 shows a configuration of a color image forming apparatus arranged in FIG.
Shown in

FIG. 6 is a cross-sectional view of a main part of a color image forming apparatus, in which I, II, III and IV are image carrier units, which are electrophotographic photosensitive members having a photoconductive layer. Image carriers 101a, 102a, 103a, and 10
4a, chargers 101b, 102b, 103b, 104
b, transfer units 101c, 102c, 103c, 104c,
It has developing units 101d, 102d, 103d, 104d, exposing units 101e, 102e, 103e, 104e, and cleaners 101f, 102f, 103f, 104f, respectively.

In an apparatus such as a color image forming apparatus which requires multicolor toner transfer, a plurality of image carriers 101a to 104a are arranged in parallel as shown in FIG. For II, III, IV, for example, Y (yellow),
A color image can be formed by giving each of the toner transfer functions of M (magenta), C (cyan), and Bk (black).

[0005] In order to form a color image, first, the image carrier 1 rotating in the image carrier unit I is used.
01a is charged by a charger 101b, and the image carrier 101 is charged by an exposure device 101e indicated by an arrow.
Exposure is performed on a, and a latent image is formed on the photoconductive layer on the image carrier 101a, and this latent image is developed by the developing device 101d to be visualized as a yellow toner image.

On the other hand, a transfer material (not shown) is conveyed by a transfer belt 3 driven by a transfer belt driving pulley 5 and a transfer belt driven pulley 4, and the yellow toner image carried on an image carrier 101a is transferred to a transfer unit 101c. The transfer material transferred onto the transfer material by the action of (1) and having received the transfer of the yellow toner image is transported to the next image carrier unit II. The untransferred yellow toner remaining on the photoconductive layer of the image carrier 101a is removed by the cleaner 101f, and the image carrier 101a is prepared for the next new latent image formation.

In the next image carrier unit II, a magenta toner image is formed on the image carrier 102a through the same process as described above, and this magenta toner image is transferred to the transfer device 10a.
The image is transferred onto the transfer material by the action of 2c.

Thereafter, the image carrier units III,
In the IV, a cyan toner image and a black toner image are formed on the image carriers 103a and 104a, respectively, and these cyan and black toner images are transferred to the transfer units 103c and 103c.
The transfer is performed sequentially on the transfer material by the action of 04c, and a desired color image is formed on the transfer material.

Next, a rotation driving mechanism of the image carriers 101a to 104a will be described with reference to FIGS. still,
FIG. 7 is a plan sectional view of a main part of a conventional color image forming apparatus.
FIG. 9 is a rear view of a main part of the color image forming apparatus, and FIG. 9 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism in the color image formation apparatus.

In a color image forming apparatus in which a plurality of image carriers 101a to 104a are arranged in tandem, the image carrier 1 is used to execute a color electrophotographic process.
A drive unit 1 that is detachable from the apparatus is provided in order to independently rotate and drive 01a to 104a. The drive unit 1 is configured such that the rotation drive motors MC <b> 1 to MC <b> 4
To 104a for driving, which is attached to the member BP.

Here, the image carrier supporting shaft A is provided on the member FP.
Members T1 to T4 having 1 to A4 are provided, and the image carrier supporting shafts A1 to A4 extend from the member FP toward the other member BP.

At one end of each of the image carriers 101a to 104a on the side of the rotation drive motors MC1 to MC4, flanges BS1 to BS4 with shafts for transmitting a rotational force are mounted. Flanges FF1 to FF4 each having a center hole are attached to the end of each of the image carriers 101a to 104a opposite to the side where the flanges BS1 to BS4 with shafts are provided.

The member T1 provided in the member EP
The image carrier support shafts A1 to A4 extending from the portions T1 to T4 are fitted into the center holes of the flanges FF1 to FF4 attached to the member FP side of the image carriers 101a to 104a, and the respective image carriers 101a to 104a. The image bearing members 101a to 104 are supported by supporting the shaft portions of shaft flanges BS1 to BS4 fixed to one end of the image bearing members 101a to 104.
a is rotatably supported.

FIG. 10 shows the details of the configuration around the rotary drive motor MC1. In addition, other rotary drive motor MC
Since the configuration of the peripheral portions of 2 to MC4 is the same, the illustration and description thereof are omitted.

As shown in FIG. 10, a rotary drive motor MC
1, a motor shaft 11 is disposed at the center thereof.
Is a bearing BA built into the rotary drive motor MC1,
It is rotatably mounted by BB. The motor shaft 11 is bent at the shaft of the shaft-mounted flange BS1 attached to one end of the image carrier 101a.
They are connected by P.

The rotation drive motor MC1 of the motor shaft 11
An encoder EC is disposed in a portion protruding from the rear,
An encoder signal detector ED for detecting an encoder signal accompanying the rotation of the motor shaft 11 is provided on a part of the outer periphery of the encoder EC. In addition, the encoder EC
The encoder signal detector ED is covered with a cover 12 in order to prevent them from dust and damage.

With the above arrangement, the image carriers 101a to 104a in the tandem type color image forming apparatus are provided.
And the motor shafts 11 of the rotary drive motors MC1 to MC4, the torque is transmitted from the rotary drive motors MC1 to MC4 to the image carriers 101a to 104a,
The image carriers 101a to 104a are independently driven to rotate.

In rotating the image carriers 101a to 104a, the rotary drive motors MC1 to MC4 attached to the drive unit 1 have a motor shaft 11 and a shaft attached to one end of the image carriers 101a to 104a. In order to rotate each of the image carriers 101a to 104a at a desired speed in a state where the shaft portions of the flanges BS1 to BS4 are connected to each other by a flexible shaft coupling CP, an encoder EC is installed at the rear end of the motor shaft 11, and A signal proportional to the rotation speed from the encoder EC is detected using an encoder signal detector ED, and control is performed such that the rotation drive motors MC1 to MC4 are driven at an appropriate rotation speed using the detected signal. I have.

In the above description, an example in which four image carriers are arranged in tandem has been described. However, the type of driving the image carriers is not limited to this, and the number of image carriers is not limited. .

[0020]

However, in the above-mentioned conventional image carrier rotation drive mechanism, the rotation drive motors MC1 to MC4 are not required to be driven with high accuracy, even though the image carriers 101a to 104a are to be driven. Image carrier 10
1a to 104a are configured to be detachable from each other, so that the rotation driving motors MC1 to MC4 and the image carriers 101a to
4a is connected to the motor shaft 11 using a flexible shaft coupling CP.
Since the configuration in which the encoder EC is arranged on the rear end is adopted, the rotation of the motor shaft 11 itself having the encoder EC is eventually controlled.

For this reason, deterioration of rotation transmission accuracy is unavoidable due to the effects of torsion, elasticity, distortion and the like between the image carriers 101a to 104a and the drive motors MC1 to MC4. There is a problem that it is difficult to control the rotation well.

In the case of using an optical encoder which is generally frequently used, the eccentricity (including mounting error) of the encoder slit array arranged on the circumference, the variation of the interval, the distortion,
Since the rotation speed is controlled by an encoder signal including an error caused by axial runout, the actual rotation of the image carrier can be performed with high precision despite the fact that the control signal controls the rotation with sufficient accuracy. There was a problem that it could not be controlled. In particular, since the eccentricity of the encoder slit row is synchronized with the rotation cycle of the image carrier, the influence on the control error is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an image carrier rotating drive mechanism of an image forming apparatus capable of rotating an image carrier with high precision. It is in.

[0024]

In order to achieve the above object, according to the first aspect of the present invention, the shafts of the image carriers and the drive shafts of the rotary drive source are arranged in one or more rows. In an image carrier rotating drive mechanism of an image forming apparatus in which an image carrier is rotationally driven by a rotational drive source, the encoder is provided on a shaft portion of the image carrier, and at least one encoder is provided on a periphery of the encoder. And two encoder signal detectors.

According to a second aspect of the present invention, in the first aspect of the present invention, the encoder is provided on a shaft portion of a flange attached to one end of the image carrier on the side of the rotation drive source.

According to a third aspect of the present invention, in the first aspect of the present invention, the encoder is provided on a flange attached to one end of the image carrier on the side of the anti-rotational drive source.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the encoder is provided on a shaft portion penetrating the image carrier.

The fifth aspect of the present invention provides the first, second, and third aspects.
Alternatively, in the invention described in Item 4, the two encoder signal detectors are arranged to face each other on the circumference of the encoder.

Therefore, according to the first to fourth aspects of the present invention, the encoder is directly provided on the shaft that rotates integrally with the image carrier, so that the rotational speed fluctuation of the image carrier is directly reflected on the encoder. Can be used as a control signal, and the image carrier can be driven to rotate with high accuracy.

According to the fifth aspect of the present invention, the rotation speed fluctuation of the image carrier can be more accurately detected, and the rotation control of the image carrier is performed using the accurately detected speed fluctuation amount. By doing so, the image carrier can be driven to rotate with higher precision.

[0031]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> FIG. 1 is a side sectional view of the periphery of a rotation drive motor of an image carrier rotation drive mechanism according to Embodiment 1 of the present invention. The structure of the mechanism other than that shown in FIG. 1 is the same as that of the conventional image carrier rotating drive mechanism shown in FIGS. Therefore, in the following, the same elements as those shown in FIGS. 6 to 10 will be described using the same reference numerals.

As shown in the figure, a motor shaft 11 is provided at the center of the rotary drive motor MC1, and the motor shaft 11 is rotatably supported by bearings BA and BB incorporated in the rotary drive motor MC1. The motor shaft 11 is connected to a shaft of a shaft-mounted flange BS1 attached to one end of the image carrier 101a by a bending shaft joint CP.

In the present embodiment, the encoder EC is provided on the shaft of the flange BS1 attached to one end of the image carrier 101a, which is an electrophotographic photosensitive member. Is provided with an encoder signal detector ED1 for detecting an encoder signal associated with the rotation of the image carrier 101a. Note that the encoder EC and the encoder signal detector ED1 are covered with a cover 12 to prevent them from being dusted or damaged.

By connecting the image carriers 101a to 104a in the tandem type color image forming apparatus and the motor shafts 11 of the rotary drive motors MC1 to MC4 by bending joints CP by the configuration shown in FIG. ＭＣMC4 transmits a rotational force to each of the image carriers 101a to 104a, and the image carriers 101a to 104a are independently driven to rotate.

In the above, in the present embodiment, the encoder EC is arranged on the shaft of the flanges BS1 to BS4 attached to the ends of the image carriers 101a to 104a. Flexible shaft coupling CP
, But not the image carrier 101a-104
The rotation speed fluctuation of a is directly reflected on the encoder EC, and a signal based on this can be used as a control signal,
The image carriers 101a to 104a can be driven to rotate with high precision.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a side cross-sectional view of the periphery of the rotation drive motor of the image carrier rotation drive mechanism according to the second embodiment of the present invention. The configuration of FIG. 7 to FIG.
Is the same as that of the conventional image carrier rotation drive mechanism shown in FIG. Therefore, in the following, the same elements as those shown in FIGS. 6 to 10 will be described using the same reference numerals.

In this embodiment, as in the first embodiment, the motor shaft 11 is provided at the center of the rotary drive motor MC1.
The motor shaft 11 is rotatably supported by bearings BA and BB incorporated in the rotary drive motor MC1. The motor shaft 11 is provided with a shaft-mounted flange BS attached to one end of the image carrier 101a.
It is connected to one shaft part by a bending shaft joint CP.

In this embodiment, the encoder EC is provided on the flange FF attached to the other end of the image carrier 101a. An encoder signal detector ED1 for detecting an encoder signal accompanying the rotation of 101a is provided. Note that the encoder EC and the encoder signal detector ED1 are covered with a cover 12 to prevent them from being dusted or damaged.

In the above, since the image carrier 101a and the flange FF are integrally formed, this flange F
By installing the encoder EC on F, the same effect as in the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a side sectional view of the periphery of the rotation drive motor of the image carrier rotation drive mechanism according to Embodiment 3 of the present invention, and is similar to FIG.

In the present embodiment, in addition to the structure of the first embodiment, an encoder signal detector ED2 is connected to the encoder EC.
At the position facing the encoder signal detector EC1 on the outer peripheral portion of.

When the rotation of the image carrier is controlled by a rotation drive source, the rotation of the image carrier is controlled based on the encoder signal. Encoder signal Es detected by one encoder signal detector ED1.
1 is represented by the following equation.

Encoder signal Es1 ≒ speed deviation Er1 + encoder eccentricity Ec1 (1) In addition to the single encoder signal detector ED1, the following equation is obtained by further adding the encoder signal detector ED2 on the circumferentially opposite side.

The encoder signal Es2 ≒ the speed deviation Er2 + the encoder eccentricity Ec2 (2) Here, since the encoder signal detectors ED1 and ED2 are provided at opposing positions, the following relationship exists between the signals based on the eccentricity. To establish.

Encoder eccentricity Ec1 = −Encoder eccentricity Ec2 (3) Speed deviation Er1 = Speed deviation Er2 (4) Accordingly, the true speed deviation can be obtained by the following equation.

Velocity deviation Er = {(1) + (2)} / 2 (5) = {encoder signal Es1 + encoder signal Es2} / 2 (6) That is, each encoder disposed at a position facing each other By summing the signals Es1 and Es2 detected by the signal detectors ED1 and ED2 and reducing the sum to 1/2, a value close to the true value of the speed deviation can be obtained.

Therefore, according to the present embodiment, in addition to the configuration shown in the first embodiment, the encoder signal detector ED
By further increasing the circumference, it is possible to more accurately detect the rotational speed fluctuation of the image carrier 101a as shown in Expression (6), and these accurately detected speed fluctuation amounts The image carrier 101a can be rotationally driven with higher precision by controlling the rotation of the image carrier 101a by using.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a view similar to FIG. 2 for explaining the fourth embodiment.

In this embodiment, in addition to the configuration of the second embodiment, the encoder signal detector ED2 is connected to the encoder EC.
At the position facing the encoder signal detector ED1.

According to the present embodiment, the same effects as in the third embodiment can be obtained.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a side sectional view of the periphery of the rotation drive motor of the image carrier rotation drive mechanism according to Embodiment 5 of the present invention, and is substantially the same as FIG.

In the present embodiment, unlike the structure of the first embodiment, a shaft portion SH penetrating the image carrier 101a and a front flange F for fixing the image carrier 101a to the shaft portion SH.
H and a rear flange BH are prepared, and the image carrier 101 is prepared.
The image carrier 101a is fixed to the shaft portion SH penetrating through a using a set screw 10 or the like.

The shaft SH penetrating the image carrier 101a and the motor shaft 11 of the rotary drive motor MC1 are connected by a flexible shaft coupling CP, so that the image carrier 101 is connected.
a becomes rotatable.

In this embodiment, the image carrier 10
An encoder EC is provided on a shaft portion SH passing through 1a, and an encoder signal detector ED1 for detecting an encoder signal accompanying rotation of the shaft portion SH is provided on a part of the outer periphery of the encoder EC. Note that the encoder EC and the encoder signal detector ED1 are covered with a cover 12 to prevent them from being dusted or damaged.

With the above arrangement, the rotation speed fluctuation of the image carrier 101a can be more accurately detected, and the rotation of the image carrier 101a is controlled by using the accurately detected speed fluctuation amount. The carrier 101a can be driven to rotate with higher precision.

In the present embodiment, the encoder EC is provided on the front flange FH side of the shaft portion SH, but may be provided on the rear flange BH side. Also, the encoder signal detector E
A plurality of D1s may be provided on the outer periphery of the encoder EC.

[0058]

As is apparent from the above description, claim 1
According to the inventions described in (1) to (4), since the encoder is directly provided on the shaft portion which rotates integrally with the image carrier, fluctuations in the rotation speed of the image carrier are directly reflected on the encoder, and a signal based on this is used as a control signal The image carrier can be driven to rotate with high precision.

According to the fifth aspect of the present invention, the rotation speed fluctuation of the image carrier can be more accurately detected, and the rotation control of the image carrier is performed using the accurately detected speed fluctuation amount. By doing so, an effect is obtained that the image carrier can be driven to rotate with higher precision.

[Brief description of the drawings]

FIG. 1 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism according to Embodiment 1 of the present invention.

FIG. 2 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism according to a second embodiment of the present invention;

FIG. 3 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism according to Embodiment 3 of the present invention.

FIG. 4 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism according to Embodiment 4 of the present invention.

FIG. 5 is a side sectional view around a rotation drive motor of an image carrier rotation drive mechanism according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a conventional color image forming apparatus.

FIG. 7 is a plan sectional view of a main part of a conventional color image forming apparatus.

FIG. 8 is a rear view of a main part of a conventional color image forming apparatus.

FIG. 9 is a plan sectional view of a main part of an image carrier driving mechanism in a conventional color image forming apparatus.

FIG. 10 is a side cross-sectional view around a rotation drive motor of an image carrier rotation drive mechanism in a conventional color image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1 drive unit 11 motor shaft 101a to 104a image carrier BS1 to BS4 flange with shaft CP flexible shaft coupling (coupling member) ED, ED1, ED2 encoder signal detector EC encoder FF1 to FF4 flange MC1 to MC4 rotary drive motor (rotary drive source)

Claims (5)

[Claims] 1. An image forming apparatus, comprising: connecting a shaft of image carriers arranged in one or a plurality of rows to a drive shaft of a rotary drive source by a coupling member; and rotating and driving the image carrier by the rotary drive source. In the image carrier rotating drive mechanism of the apparatus, an encoder is provided on a shaft portion of the image carrier, and at least one encoder signal detector is provided around the encoder. Carrier rotation drive mechanism. 2. An image carrier rotation drive mechanism for an image forming apparatus according to claim 1, wherein said encoder is provided on a shaft portion of a flange attached to one end of said image carrier on a rotation drive source side. . 3. The image carrier rotating drive mechanism of an image forming apparatus according to claim 1, wherein said encoder is provided on a flange attached to one end of the image carrier on the side opposite to the rotational drive source. 4. The image carrier rotating drive mechanism of an image forming apparatus according to claim 1, wherein said encoder is provided on a shaft portion penetrating the image carrier. 5. The image carrier rotation of an image forming apparatus according to claim 1, wherein said two encoder signal detectors are arranged on the circumference of said encoder so as to face each other. Drive mechanism.