JPH07140745A - Driving force transmitting mechanism for image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a failure in a change in a position in the radial direction of a shaft member, even if the shaft hole of a photoreceptor drum supported by one chamferred part is shaved by the chamferred corner part of the supporting shaft. CONSTITUTION:The shaft hole of the drum flange 5 of the photoreceptor drum 3 is constituted of a part to be fitted 5c engaged with the fitting part 6a of the supporting shaft 6 and a cylindrical bearing 5d ranging in the axial center of the part 5c. Thus, even if the part to be fitted 5c of the shaft hole is shaved and deformed by the corner part 6e of the supporting shaft 6, the axial center position relation of the photoreceptor drum 3 to the supporting shaft 6 is never changed in its radial direction because the bearing part 5d of the shaft hole is supported by the complete round part 6d of the supporting shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmission mechanism for an image forming apparatus.

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a copying machine is equipped with image forming elements such as various pulleys, gears, rollers, cams or photosensitive drums, and a driving force from a motor (driving source) is a chain. , Transmitted to these imaging elements via wires, gears or belts,
By operating these image forming elements under the associated fixed timing, the desired original image is transferred to the copy paper. By the way, since the image forming element is usually used by being supported by a supporting shaft, the driving force is transmitted from the image forming element to the supporting shaft or from the supporting shaft to the image forming element. An example of the support structure is shown in FIG. In the driving force transmission mechanism shown in the figure, a photosensitive drum 1 which is an example of the image forming element is supported by a support shaft 2. Drum flange 1 of the photoconductor drum 1
Each of a and 1b is made of aluminum or synthetic resin, and the support shaft 2 is made of a metal material. A perfect circular shaft hole 1a 'is formed at the axial center of one of the drum flanges 1a, and a perfect circular portion on one end side of the support shaft 2 is fitted into the shaft hole 1a'. A fitting portion 2a is formed on the other end side of the support shaft 2 by chamfering a part of its peripheral surface. The fitting portion 2a is fitted into the shaft hole 1b 'of the other drum flange 1b. To be Therefore, the shaft hole 1 of this drum flange 1b
A part of the inner peripheral surface of b'is formed in a chamfered shape so that it can be engaged with the fitting portion 2a of the support shaft 2. In the structure as described above, the driving force is transmitted to the support shaft 2 via a pulley (not shown) and the driving force is further transmitted to the main body of the photosensitive drum 1 via the drum flange 1b. In response to this, the photosensitive drum 1 is rotationally driven, so that the copied image formed on the surface of the photosensitive drum 1 is copied onto the transfer paper.

[0003]

However, in the conventional driving force transmission mechanism as described above, as shown in FIG. 2 (b), the fitting portion formed by chamfering a part of the peripheral surface of the support shaft 2 is used. Since the entire drum flange 1b on the other side is supported by 2a, the flat corner portion 1c of the shaft hole 1b 'of the drum flange 1b is shaved and deformed by the action of the driving force transmitted through this chamfered portion. there's a possibility that. In this way, when the flat corner portion 1c is scraped off and deformed as shown by the broken line in the figure, the entire drum flange 1b can change its position in the radial direction with respect to the support shaft 2 as shown in the image. There is a possibility that the photosensitive drum 1 may be eccentrically operated during formation, resulting in a large adverse effect on image quality. Therefore, the present invention was devised in view of the above circumstances, and it is difficult to apply a force to the flat corner portion 1c of the shaft hole 1b 'of the drum flange 1b, and the flat corner portion 1c has the above-mentioned flat corner portion 1c due to long-term use. Drive of an image forming apparatus having a mounting structure in which the axial center positional relationship with respect to the support shaft 2 of the photosensitive drum 1 which is an example of an image forming element does not change in the radial direction even if it is scraped and deformed in this way. The purpose is to provide a force transmission mechanism.

[0004]

In order to achieve the above-mentioned object, the main means adopted by the present invention is the gist thereof, but a fitting portion formed by chamfering a part of the periphery of a support shaft is used as an image forming element. Driving force transmission mechanism of an image forming apparatus which is fitted into the shaft hole of the image forming apparatus and transmits a driving force from a driving source to the image forming element from the supporting shaft or to the supporting shaft from the image forming element to perform an image forming process. In the above, in the shaft hole of the image forming element, a fitted portion having a chamfered portion that engages with the fitting portion of the support shaft and a perfect circular bearing portion that extends in the axial center direction are formed. It is a driving force transmission mechanism of the image forming apparatus.

[0005]

In the present invention, the fitted portion having the chamfered portion that engages with the fitting portion of the support shaft and the perfect circular bearing portion that extends in the axial direction are formed in the shaft hole of the image forming element. Therefore, even if the fitted part of the shaft hole is scraped and deformed,
Since the perfectly circular bearing can maintain the state of being supported by the support shaft, the axial center position of the image forming element with respect to the support shaft does not change in the radial direction.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. The following embodiments are examples of embodying the present invention and are not intended to limit the technical scope of the present invention. FIG. 1 shows the structure of a driving force transmission mechanism according to an embodiment of the present invention. FIG. 1 (a) is a side sectional view showing a state where a photosensitive drum is supported by a support shaft, and FIG. 8A is an end view of AA ′ in FIG. 7A, and FIG. 8C is an end view of BB ′ in FIG. In the driving force transmission mechanism according to this embodiment, as shown in FIG. 1, the case where the photosensitive drum 3 which is an example of an image forming element is supported by the support shaft 6 will be described as an example. That is, in this embodiment, as shown in the figure, both ends of the photosensitive drum 3 are held by the drum flanges 4 and 5, and a perfect circular shaft hole is provided at the axial center position of the drum flange 4. 4a is provided. In the shaft hole 4a,
A perfect circle portion 6c on one end side of the support shaft 6 is fitted and inserted.
Fitted in the shaft hole 5a of the drum flange 5 is a chamfered portion that engages with a fitting portion 6a formed by chamfering a part of the peripheral surface of the support shaft 6 on the other end side. Part 5c,
A perfectly circular bearing portion 5d is formed so as to extend in the axial direction. That is, the shaft hole 5a has the fitted portion 5c.
And a bearing portion 5c. In this case, the chamfered portion of the fitted portion 5c means a flat surface portion engageable with one chamfered portion of the fitting portion 6a of the support shaft 6.

Then, the fitting portion 6a of the support shaft 6 as described above
Also, the fitted portion 5c of the shaft hole 5a is not limited to one location as in the case of the above-described embodiment, and one or more other locations are provided at the opposite positions to form a so-called double chamfer structure. Good. Shaft hole 5 formed as described above
The fitting portion 6a of the support shaft 6 and the perfect circular portion 6d connected to the fitting portion 6a are fitted to a. Therefore, in the above embodiment, since the support 6 is not displaced in the radial direction, the stress on the fitting portion 6a is reduced, and the both-end corners 6e, 6e of the fitting portion 6a of the support shaft 6 are used for many years. Even if the fitted portion 5c of the shaft hole 5a of the drum flange 5 is scraped and deformed, the drum flange 5 is always stably supported by the perfect circular portion 6d of the support shaft 6, and therefore the photosensitive drum 3 The positional relationship of the shaft center with respect to the support shaft 6 does not change in the radial direction, and the problem as in the case of the conventional structure does not occur. Since the axial center positional relationship is maintained in this manner, it is possible to prevent the problem that the deformation is further increased by the deformation and causes a larger problem. In the above embodiment, the case where the photoconductor drum 3 is handled as an example of the image forming element has been described. However, such a mounting structure has various structures such as a pulley, a gear, a roller, and a cam. It goes without saying that it can be applied to elements.
Therefore, a stable image can be obtained for a long period of time in the driving force transmission mechanism adopting the above-mentioned mounting structure.

[0008]

As described above, according to the present invention, the fitting portion formed by chamfering a part of the periphery of the supporting shaft is fitted into the shaft hole of the image forming element, and the driving force from the driving source is applied to the supporting shaft. From the image forming element to the image forming element or from the image forming element to the supporting shaft to perform an image forming process, in a driving force transmitting mechanism of an image forming apparatus, the supporting shaft is fitted in the shaft hole of the image forming element. A chamfered drive mechanism for an image forming apparatus, characterized in that a fitted portion having a chamfered portion that engages with the mating portion and a perfect circular bearing portion that extends in the axial direction of the fitted portion are formed. The stress on the image forming portion is moderated, and even if the shaft hole portion is shaved and changed during normal use of the image forming element, the axial center positional relationship with respect to the support shaft of the image forming element changes in the radial direction. Can be avoided for a long time Those images can be obtained.

[Brief description of drawings]

1A and 1B are views showing a structure of a driving force transmission mechanism according to an embodiment of the present invention, in which FIG. 1A is a side sectional view in which a photosensitive drum is supported by a support shaft, and FIG. AA 'end view in (a), (c) is a BB' end view in (a).

FIG. 2 is a view showing a mounting structure for a supporting shaft of a photosensitive drum which constitutes a conventional driving force transmission mechanism,
(A) is a side sectional view, (b) is a CC ′ end view in (a).

[Explanation of symbols]

 3 ... Photosensitive drum (image forming element) 5 ... Drum flange 5a ... Shaft hole 5c ... Fitted part 5d ... Bearing part 6 ... Support shaft 6a ... Fitting part 6d ... Round part 6e ... Corner part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Ito 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Industry Co., Ltd. (72) Shinji Yamamoto 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture No. 28 Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A fitting portion formed by chamfering a part of the periphery of a support shaft is fitted into a shaft hole of an image forming element, and a driving force from a driving source is applied from the support shaft to the image forming element, or In a driving force transmission mechanism of an image forming apparatus that transmits an image from an image forming element to the support shaft to perform an image forming process, a chamfered portion that engages with a fitting portion of the support shaft is provided in the shaft hole of the image forming element. A driving force transmitting mechanism for an image forming apparatus, comprising: a fitted portion having the fitting portion and a perfectly circular bearing portion extending in an axial direction of the fitting portion.