JPH10254296A - Rotating body driving transmitting device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating body driving transmitting device for image forming device that does not generate sudden rotational irregularity even when a declination exists between a rotating body such as a photoreceptor or a belt driving roller and the driving shaft of the rotating body. SOLUTION: The engaging surface of a boss 38 fixed on the driving shaft 32 of the photoreceptor 12 with the flange 39 of the photoreceptor 12 is formed to be a projecting spherical surface, and the engaging surface of the flange 39 of the photoreceptor 12 with the boss 38 is formed to be a recessed spherical surface corresponding to the projecting spherical surface of the boss 38. Even when the declination exists and the engaging surfaces of the flange 39 and the boss 38 are positionally deviated due to rotation because the engaging surfaces of both of them are the spherical surfaces, it becomes the continuity of minute deviation and the sudden rotational irregularity of the photoreceptor 12 does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transmission device for a rotating body such as a photoreceptor in an image forming apparatus.

[0002]

2. Description of the Related Art FIG. 1 shows a color copying machine as an example of an image forming apparatus. The copier includes a scanner unit 1 for reading a document, an image processing unit 2 for electrically processing a digital output signal transmitted from the scanner unit 1, and image recording information of each color from the image processing unit 2. And a printer unit 3 for forming an image on transfer paper based on the image data. Scanner unit 1
Has a lamp 5 (for example, a halogen lamp) for scanning and illuminating the original on the original mounting table 4, and the reflected light from the original when illuminated by the lamp 5 passes through mirrors 6, 7, 8 to form an imaging lens. 9 is incident.

[0003] The image light is imaged on a three-line CCD 10 as an image information reading section by an imaging lens 9, and is converted into a digital signal for each of red, green and blue components and output. Red output from the scanner unit 1,
The digital signals of the green and blue components are sent to the image processing unit 2 and subjected to necessary processing, and are converted into recording information of each color, that is, black, cyan, magenta and yellow signals.

[0004] The recording information converted by the image processing unit 2 is input to the printer unit 3 and sent to the laser beam emitting device 11. The image forming unit of the printer unit 3 shown in FIG. 1 includes a laser beam emitting device 11, a photoconductor 12, a charging device 13, and a developing device 1.
4, an intermediate transfer device 15 and a cleaning device 16. The developing device 14 includes black, cyan, magenta, and yellow developing units (14Bk, 14Bk) corresponding to the recording information.
C, 14M, and 14Y), and is supported by the image forming apparatus main body in a rotatable configuration, and a developing unit for each color visualizes a latent image formed on the photoconductor 12 as necessary (see FIG. 1 (position of 14Bk shown in FIG. 1). Further, a density sensor 17 for detecting the image density on the developed photoconductor 12 is disposed downstream of the developing device 14, and the density signal from the density sensor 17 supplies toner to the developing section and determines development conditions. Changes are made, and control is performed to maintain the image density appropriately.

The intermediate transfer device 15 includes an intermediate transfer belt 19 supported by a driving roller 18 and a driven roller, a belt transfer device 20, an image synchronization sensor 22, a paper transfer device 21, and the like. The image developed on the photoconductor 12 is transferred onto the intermediate transfer belt 19 by the belt transfer device 20 and further transferred onto transfer paper by the paper transfer device 21.

In the case of forming a color image, it is necessary to superimpose the recording information of each color. In this apparatus, however, the configuration is such that the color is superimposed on the intermediate transfer belt 19. In FIG. 1, the black developing unit 14Bk is at the developing position, and the laser beam emitting device 11 forms a black latent image on the photoconductor 12 according to the black recording information output from the image processing unit 2. The black latent image on the photoconductor 12 is visualized by the developing unit 14Bk, and is transferred onto the intermediate transfer belt 19 by the belt transfer device 20. The image formation at this time is started in accordance with the detection signal of the position in the feed direction on the belt by the image synchronization sensor 22. When the transfer of the black image onto the intermediate transfer belt is completed, the developing device 14 rotates, for example, the cyan developing portion 14C moves to the developing position, and the laser emitting device 11 outputs the cyan recording information in accordance with the detection signal of the image synchronization sensor 22. To start forming. Hereinafter, the same operation is repeated for each color to form a superimposed color image of each color on the intermediate transfer belt 19, and then the image is transferred onto the transfer paper by the paper transfer device 21.

The belt cleaning device 23 is retracted to the retracted position during the color image forming operation, moves to the operating position after the image on the belt is transferred to the transfer paper, and removes the toner remaining on the belt. Collect and prepare for the next image operation.

The transfer paper P is supplied from a so-called front-loading paper feed tray 24 or a manual paper feeder 25 configured to perform a replenishing operation by being pulled out to the front side of the apparatus. Then, the toner image is sent to the transfer area at the same timing as the image forming timing, and the toner image on the intermediate transfer belt 19 is transferred by the paper transfer device 21. Then, the transfer paper P on which the image has been transferred to the upper surface is sent to a fixing device 28 by a paper conveying device 27, and the toner image is pressed and heated and fixed by the fixing device 28, and is discharged outside the device by a discharge roller 29. . The paper feed tray section 24 must have a certain height because it is necessary to stroke the stack of stacked paper up and down in order to secure a certain amount of stacked paper and make the leading edge area of the sheet abut on the pickup roller.

Below the conveying device 27 and the fixing device 28, a shielding plate 31 for preventing foreign matters such as toner and paper dust from dropping onto the transfer paper P from the image forming section is formed by using a main body side plate. And is attached so as to cover the paper feed tray section 24.

FIG. 2 shows an example of a drive transmitting device for a rotating body in this type of image forming apparatus. The device of this example is a device for rotatingly driving the photoconductor 12, and a supporter 34 in which a drive shaft 32 of the photoconductor 12 is fixed to a side plate 33 of the image forming apparatus main body.
, And a driving gear 35 is fixed to one end. A boss 36 having a tapered surface for holding the photosensitive member 12 coaxially is fixed to the drive shaft 32 by press-fitting or the like, and the tapered surface of the flange 37 of the photosensitive member 12 and the photosensitive member 12 are indicated by arrows in the drawing as shown in the figure. When pressed in the direction A, the photosensitive member 12 is engaged to rotate integrally with the drive shaft 32.

FIG. 3 shows another example of a drive transmission device for a rotating body in this type of image forming apparatus. This device rotates the belt driving roller 18 of the transfer device 15.
A drive shaft 40 provided in the image forming apparatus main body is rotatably supported by a bearing 41 and is rotated by a drive unit (not shown). A drive boss 42 is fixed to a shaft end of the drive shaft 40. On the other hand, a shaft 45 is provided on the belt drive roller 18 of the transfer device 15, and the drive shaft 40 and the shaft 4
The transfer belt 19 runs by rotating the belt drive roller 18 with the engagement of the transfer belt 19. For this reason, a driven coupling 44 is integrally fixed to one end of a shaft 45 of the driving roller 18. When the transfer device 15 is set in the image forming apparatus main body, the boss 42 and the coupling 44 are pressed against each other by a tapered surface. And drive transmission. The transfer belt 19 is provided with a stopper 43 for preventing the transfer belt 19 from moving.

[0012]

In the conventional example shown in FIG. 2, the boss 36 provided on the drive shaft 32 engages with the tapered surface of the flange 37 of the photosensitive member 12, so that as shown in FIG. In addition, there is a problem that if there is a declination between the two, the contact becomes not point contact but point contact, and drive transmission becomes insufficient, and slip on the engagement surface is likely to occur. In addition, since there is a declination between the two, there is also a problem that the contact position of the two changes due to the rotation, the rotation state of the photoconductor 12 is not uniform, and irregular sudden fluctuation occurs.

That is, in the state shown in FIG. 3, C and D in FIG.
Although both are in contact. When rotated by 180 °, the drive shaft 32 and the photoconductor 12 have a declination, so that the state changes to a state where the drive shaft 32 and the photoconductor 12 come into contact with each other at E and F in FIG. This change in the contact point is caused by
2 is pressed in the direction of arrow A in FIG. 2, so that the contact point does not change during the elastic deformation according to the pressing force, and the position changes rapidly when the elastic deformation range is exceeded. Happens. For this reason, the movement of the photoconductor 12 becomes irregular,
This causes unevenness and color misregistration on the image, resulting in deterioration of the image quality.

Also, in the conventional example shown in FIG.
Similarly to the above example, when the transfer device 15 is set in the image forming apparatus main body, the same deviation angle may occur due to the positioning accuracy between the transfer device 15 and the image forming apparatus main body.
Then, the traveling accuracy of the transfer belt 19 may become unstable due to the irregular change in the rotation of the belt driving roller 18, and the vibration of the entire transfer device 15 may occur due to the vibration during the operation of the belt driving roller 18. There is a problem that the image quality is deteriorated due to unevenness and color shift on the image.

In view of the above drawbacks, the present invention does not cause abrupt rotation unevenness even when there is a declination between a rotating body such as a photoreceptor or a belt drive roller and its drive shaft. It is an object of the present invention to provide a rotating body drive transmission device of an image forming apparatus capable of obtaining a good image.

[0016]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising a rotating body drive transmitting device, wherein an image is formed by inserting a driving shaft which rotates while holding the rotating body into a rotating body. In the rotating body drive transmission device of the forming apparatus, the surface shape of the engaging portion between the rotating body and the drive shaft is formed into a convex spherical shape on one side and a concave spherical shape on the other side, and the rotation is performed by engaging the concave and convex spherical shape. The angle between the body and the drive shaft is variable.

According to a second aspect of the present invention, there is provided a rotating body shaft,
In a rotating body drive transmission device for an image forming apparatus, a drive shaft for rotating and driving the rotating body is engaged when a detachable unit is attached to the image forming apparatus main body. The shape of the surface of the engaging portion with one is convex spherical, the other is concave spherical, and the angle between the rotating body and the drive shaft is made variable by engaging the concave and convex spherical shape. .

According to a third aspect of the present invention, in the radial dimension of the spherical shape of the surface of the engagement portion, the dimension on the convex spherical surface side is set to a tolerance in which a radius is equal to or smaller than a nominal dimension, and It is characterized in that the dimension on the spherical surface side is set to a tolerance where the radius is equal to or larger than the nominal dimension.

According to a fourth aspect of the present invention, the engagement range of the spherical engagement portion is 60 ° to 90 ° with respect to the axial direction.
Is formed as a range.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a cross-sectional view illustrating a first embodiment of a rotating body drive transmission device of an image forming apparatus according to the present invention. This device improves the engagement between the boss 38 provided on the drive shaft 32 of the photoconductor 12 and the flange 39 of the photoconductor 12 shown in FIG. 2. The boss 38 is fixed to the drive shaft 32. The engagement surface of the boss 38 with the flange 39 of the photoconductor 12 has a convex spherical shape. On the other hand, the engagement surface of the flange 39 of the photoconductor 12 with the boss 38 is the boss 3
8, a pressing force is applied by a spring or the like (not shown) so that the two are pressed against each other as in the conventional example of FIG. 2, and the driving force is transmitted by surface contact. It is.

Here, since the engaging surfaces of the two are spherical, even if there is a declination, the flange 39 of the photoreceptor 12 can be used.
4 does not come into point contact as shown in FIG. 4, and even if the positions of the two engaging surfaces are deviated by rotation, a slight shift continues, and a sudden No 12 rotation unevenness occurs.

It is conventionally known that in the case of tapered surface engagement, the smaller the taper angle, the greater the drive transmission force at the engagement surface. However, in this embodiment, as shown in the figure, In the range indicated by B, the angle of the engagement surface is substantially reduced, and the drive transmission force is increased. In order to ensure the engagement in the range of B, the dimension on the boss 38 side which is a convex spherical surface with respect to the radius R of the spherical surface should be 0-a tolerance, and the dimension on the flange 39 side which is a concave spherical surface should be It is preferred to be + b0 tolerance.
The range of B is preferably in the range of 60 ° to 90 ° with respect to the axial direction.

FIG. 6 is a sectional view showing a second embodiment of the rotating body drive transmission device of the image forming apparatus according to the present invention. This device has an improved form of engagement between a boss 46 provided on a drive shaft 40 shown in FIG. 3 and a coupling 47 provided on a shaft 45 of the belt drive roller 18 and is fixed to the drive shaft 40 on the image forming apparatus main body side. The shape of the engaging surface of the boss 46 thus formed is a convex spherical shape, and the shape of the engaging surface of the coupling 47 fixed to the shaft 45 of the belt drive roller 18 is a concave spherical shape. Thereby, the operation is similar to that of the previous embodiment. In the embodiment shown in FIG. 6, in order to reduce the axial dimension of the boss 46 and the coupling 47, the spherical shape is formed only in the range B shown in FIG. In the case of this embodiment, it is possible to obtain a sufficient engagement even if the spherical shape tolerance of the two is ± tolerance, and thus it is possible to obtain a sufficient drive transmission force.

In the above two embodiments, the driving side has a convex spherical shape and the driven side has a concave spherical shape.

[0025]

According to the first aspect of the present invention, there is provided a rotating body drive transmission device for an image forming apparatus, as described above, wherein the rotating body of the image forming apparatus is inserted into the rotating body while holding the rotating shaft. In the drive transmission device, the surface shape of the engaging portion between the rotating body and the drive shaft is one of a convex spherical shape, the other is a concave spherical shape, and the angle formed between the rotating body and the drive shaft by the engagement of the concave and convex spherical shape. Variable, so that surface contact can be obtained even when there is a declination between both, sudden rotation unevenness of the rotating body due to change in the engagement surface can be prevented, and a good image without unevenness and color shift can be obtained. There is an effect that it becomes possible to obtain.

In the rotating body drive transmission device for an image forming apparatus according to the second aspect, as described above, the shaft of the rotating body and the drive shaft for rotating the rotating body are provided in the image forming apparatus main body. In the rotating body drive transmission device of the image forming apparatus, which is engaged when the detachable unit is mounted, the surface shape of the rotating body shaft and the engaging portion with the drive shaft are formed such that one is a convex spherical surface and the other is a convex spherical surface. Since the angle between the rotating body and the drive shaft is variable due to the concave spherical shape and the engagement of the concave and convex spherical shape, surface contact can be obtained even if there is a declination between them, and sudden change due to the change of the engagement surface There is an effect that rotation unevenness can be prevented and a good image without unevenness and color shift can be obtained.

According to the third aspect of the present invention, as described above, of the radius of the spherical shape of the surface of the engagement portion, the dimension of the convex spherical surface is defined as the nominal size. On the other hand, the radius is made equal or smaller, and the dimension on the concave spherical surface side is made equal or larger than the nominal size. There is an effect that the engagement in a certain range is ensured, a sufficient drive transmission force is obtained by the engagement, and the contact state becomes stable.

According to the fourth aspect of the present invention, as described above, the engagement range of the spherical engagement portion is set to be 60 ° to 9 ° with respect to the axial direction.
Since it is formed as a range of 0 °, in addition to the above-mentioned common effects, the engagement is performed in a range where the inclination angle is small, the drive transmission force by the engagement is sufficiently obtained, and the effect that the contact state is also stable is obtained. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a color copying machine as an example of an image forming apparatus.

FIG. 2 is an enlarged cross-sectional view illustrating an example of a drive transmission device for a photoconductor in the image forming apparatus illustrated in FIG.

FIG. 3 is an enlarged cross-sectional view illustrating an example of a drive transmission device for a belt drive roller in the image forming apparatus illustrated in FIG.

FIG. 4 is an enlarged cross-sectional view showing a state in which a problem due to a deflection angle occurs in the apparatus of FIG. 2;

FIG. 5 is a cross-sectional view illustrating a first embodiment of a rotating body drive transmission device of the image forming apparatus according to the present invention.

FIG. 6 is a cross-sectional view showing a second embodiment of a rotating body drive transmission device of the image forming apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanner part 2 Image processing part 3 Printer part 4 Document mounting table 5 Lamp 6, 7, 8 Mirror 9 Imaging lens 10 3-line CCD 11 Laser light emitting device 12 Photoconductor 13 Charging device 14 Developing device 15 Intermediate transfer device 16 Cleaning Apparatus 17 Density sensor 18 Drive roller 19 Intermediate transfer belt 20 Belt transfer device 21 Paper transfer device 22 Image synchronization sensor 23 Belt cleaning device 24 Feed tray unit 25 Manual feed unit 26 Registration roller 27 Paper transport device 28 Fixing device 29 Discharge roller 32 Drive Shaft 33 Side Plate 34 Supporter 35 Drive Gear 36 Boss 37 Flange 38 Boss 39 Flange 40 Drive Shaft 41 Bearing 42 Drive Boss 43 Detent Stop 44 Follower Coupling 45 Shaft 46 Boss Ring P Transfer Paper

Claims (4)

[Claims] 1. A rotating body drive transmission device for an image forming apparatus, wherein a driving shaft that holds and rotates the rotating body is inserted into the rotating body, wherein a surface shape of an engagement portion between the rotating body and the driving shaft is changed. One of which has a convex spherical shape, the other has a concave spherical shape, and the angle formed between the rotary body and the drive shaft is variable by engagement of the concave and convex spherical shape. . 2. A rotating body drive transmission device of an image forming apparatus, wherein a shaft of a rotating body and a drive shaft for rotating and driving the rotating body are engaged when a detachable unit is attached to an image forming apparatus main body. In, the surface shape of the engaging portion between the shaft of the rotating body and the drive shaft, one is a convex spherical shape, the other is a concave spherical shape, the engagement of the concave and convex spherical shape of the rotating body and the drive shaft A rotating body drive transmission device for an image forming apparatus, wherein the angle formed is variable. 3. Among the radial dimensions of the spherical surface of the engagement portion, the dimension on the convex spherical surface side is a tolerance to make the radius equal to or smaller than the nominal dimension, and the dimension on the concave spherical surface side is the nominal dimension. 3. The drive transmission device for a rotating body of an image forming apparatus according to claim 1, wherein a tolerance is set so that a radius is equal to or larger than the radius. 4. The image forming apparatus according to claim 1, wherein an engagement range of said spherical engagement portion is formed in a range of 60 ° to 90 ° with respect to an axial direction. Rotary body drive transmission device.