JPH05333721A - Transfer roller - Google Patents

Abstract

PURPOSE:To reduce the number of parts, and to improve assembling accuracy so that copying accuracy may be improved by integrating a main body frame with a bearing holding part as to both end holding parts of a transferring roller. CONSTITUTION:A bearing groove 15a having undercut on an upper edge is provided on a bearing 15 in a state where diameters are the same so that the rotary shaft 4a of the transferring roller 4 may fit in and in a state where the shaft 4a can be fixed when the shaft 4a is inserted from an upper part. Members provided with pawls 17 on the respective top ends while interposing a projection 18 are integrally molded with the main body frame 11, and bearing guides 14 having respective parallel surfaces on the back of the member are integrally molded with the main body frame 11 as to the main body frame 11. In this case, the bearing 15 is molded to be H-shaped, the members provided with the pawls 17 on the top slide in the gap part 19 of the bearing 15, and also both side surface in a right angle direction to the groove 15a slide with the parallel surface of the bearing guide 14. Thus, since the transferring roller holding part having the bearing guide is integrally molded with the main body frame, a screwing process can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer roller, and more particularly to improvement of a bearing portion of a transfer roller used in an image forming apparatus in an electrophotographic process.

[0002]

2. Description of the Related Art As is well known, many proposals have already been made for copying machines, and in recent years, electrophotographic copying machines have become the mainstream. As a basic configuration of such an apparatus, as shown in the schematic diagram of FIG. 4, the photosensitive drum 1 / charger 2 /
The exposure device 3, the developing device 5, the transfer roller 4, the static eliminator 7, and the cleaner 8 are arranged clockwise around the photosensitive drum (OPC) 1 to form an image forming apparatus. In addition, 6 is a transfer paper. In the image forming apparatus as shown in FIG. 4, the surface of the photoconductor drum 1 is negatively charged by the charger 2, and then the exposure device 3 forms a latent image on the surface of the photoconductor drum 1 by, for example, a laser beam. It Then, the latent image is developed by the developing device 5, and the developed image is transferred to the transfer paper 6 by applying a transfer voltage having a positive polarity to the transfer roller 4. In the image forming apparatus as described above, a fixing device (not shown) is normally attached to the main body frame made of synthetic resin or the like in succession to the transfer roller 4 in addition to the respective devices shown in FIG. The transfer paper 6 from the tray is fixed via the transport unit and discharged as a copy.

[0003]

By the way, the conventional structure of such a transfer roller 4 is as shown in the exploded perspective view of FIG.
2 is fixed by a fastening screw 13, and the holding portion 12
A bearing guide 14 is provided in the bearing guide 15, and a bearing 15 housed in the bearing guide 14 is a cushioning means 16 such as a spring.
And is configured to receive the end of the shaft 4a of the transfer roller 4, and both ends of the transfer roller 4 have the same structure. By the way, with the above configuration, the transfer roller holding portion 12 is a component separated from the main body frame 11, and accordingly, extra components such as the fastening screw 13 are naturally required. When assembling and maintaining, not only the number of steps such as the step of tightening the screws is required but also the assembly accuracy may be deteriorated due to the influence of the mounting position. Figure 4
The contact area between the photoconductor drum 1 and the transfer roller 4 shown in (4) varies, and the copy accuracy is reduced due to the variation.
Therefore, an object of the present invention is to provide a transfer roller which reduces the number of parts and improves the assembling accuracy by integrating the main body frame and the bearing holding portion, and thereby the copying accuracy. It is in.

[0004]

The present invention has been made to solve the above problems, and its gist is a transfer roller provided in an image forming apparatus in an electrophotographic process. Both ends of the transfer roller are held by a transfer roller constituted by a bearing guide provided integrally with the main body frame of the image forming apparatus, a bearing held by a claw, and a cushioning means.

[0005]

In the present invention, since the transfer roller holding portion provided with the bearing guide is formed integrally with the main body frame, the step of fastening the holding portion to the main body frame with a screw can be omitted, and the transfer roller holding portion is attached with a screw. As a result, it is possible to prevent a decrease in assembling accuracy and a decrease in copying accuracy due to a change in the contact area between the photosensitive drum and the transfer roller.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 is an exploded perspective view showing the structure of both end holding portions of the transfer roller of the present invention, and FIG.
FIG. 6 is a front view showing an assembling procedure of the holding portion shown in FIG. As shown in FIGS. 1 and 2, the bearing 15 has the same diameter so that the rotating shaft 4a of the transfer roller 4 can be mounted (fitted) and a slight undercut so that it can be fixed when inserted from above. Is provided on the upper edge of the bearing groove 15a. Further, on the back side of the bearing groove 15a, one receiving hole 15b for inserting an upper and lower cushioning means 16 such as a spring between the main body frame 11 of the image forming apparatus and a projection 18 formed integrally therewith is provided. Has been done. In addition, the main body frame 11 has the projections 18 sandwiched between the nails 1 at the tips thereof.
A member including 7 is erected by integral molding with the main body frame 11, and a bearing guide 14 having parallel surfaces is integrally molded with the main body frame 11 behind the member. In this case, the bearing 15 is formed in an H shape as shown in the figure, and the member having the claw 17 at the tip slides in the gap 19 of the bearing 15 and
Both side surfaces of the bearing 15 in the direction perpendicular to the groove 15a are configured to slide on the parallel surfaces of the bearing guide 14, respectively. The above structure is the same at both ends of the transfer roller 4.

Next, the procedure for assembling the both-end holding portions of the transfer roller according to the embodiment of the present invention will be described with reference to the front view of FIG. First, in FIG. 2, the rotary shaft 4a of the transfer roller 4 is moved from the upper side in the direction of the arrow to be fitted in the groove 15a of the bearing 15. In this case, a slight undercut is provided on the upper edge of the bearing groove 15a to stabilize the holding of the rotating shaft 4a. Next, the bearing 15 having the transfer roller 4 mounted thereon is further lowered in the direction of the arrow in this way, and the bearing 15 is moved to a predetermined position of the member having the pawl 17 at its tip. Since it is integrally molded with the same synthetic resin as the above and has a certain degree of flexibility, it is opened slightly by pushing the bearing 15 down, resulting in a so-called snap fit method, and the bearing 15 is clamped at the upper end as shown by the dotted line. While being locked and held, the bearing 15 is provided by a buffering means 16 such as a spring interposed between a receiving hole 15b formed on the back side of the bearing 15 and a projection 18 integrally formed on the body frame. The side surfaces of the bearings 15 and the bearing guides 14 having parallel surfaces are slidably held while being slidable.

Finally, FIG. 3 is a front view conceptually showing the working relationship when the transfer roller 4 according to the embodiment of the present invention is brought into contact with the photosensitive drum 1, and the buffer means 16 is vertically movable. By doing so, an appropriate roller pressure can be generated. As shown in FIGS. 1 to 3, the bearing guide 14 constituting the both-end holding portion of the transfer roller 4, the flexible member having the claw 17 at the tip, and the lower end of the cushioning means 16 are locked. Each of the projections 18 for forming is formed integrally with the main body frame 11 of the image forming apparatus by, for example, a synthetic resin. However, the embodiment shown in FIGS. 1 to 3 is one embodiment of the present invention. It is needless to say that this is merely an example and can be modified in various ways within the scope of the present invention. In any case, the point is that the bearing 15 of the transfer roller 4 is directly attached to the main body frame 11 because the holding portion of the transfer roller 4 is integrally formed and integrated with the main body frame 11. As a result, the assembling accuracy of the transfer roller 4 is stabilized as compared with the conventional means, and these parts can be easily assembled and removed.

[0009]

As described above, according to the present invention, the body frame and the bearing holder are integrated with respect to the holders at both ends of the transfer roller of the image forming apparatus in the electrophotographic process, so that the number of parts is reduced and the assembling accuracy is improved. Moreover, it is possible to provide a transfer roller which can also improve the copying accuracy, and the effect is extremely remarkable.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of both-end holding portions of a transfer roller of the present invention.

FIG. 2 is a front view showing an assembling procedure of the both-end holding portion shown in FIG.

FIG. 3 is a front view conceptually showing the operational relationship between the transfer roller and the photosensitive drum of the present invention.

FIG. 4 is a schematic diagram showing the basic configuration of a normal electrophotographic copying apparatus.

FIG. 5 is an exploded perspective view showing a configuration of both-end holding portions of a conventional transfer roller.

[Explanation of symbols]

 1 Photoconductor drum 2 Charging device 3 Exposure device 4 Transfer roller 4a Transfer roller rotating shaft 5 Developing device 6 Transfer paper 7 Static eliminator 8 Cleaner 11 Main frame 12 Transfer roller holding part 13 Screw 14 Bearing guide 15 Bearing 15a Bearing groove 15b Receiving hole 16 Buffering means 17 Claw 18 Protrusion 19 Gap

Claims (1)

[Claims] 1. A transfer roller provided in an image forming apparatus in an electrophotographic process, wherein both end holding portions of the transfer roller are held by a bearing guide and a claw integrally provided with a main body frame of the image forming apparatus. A transfer roller comprising a bearing and a cushioning means.