JPH0527654A - Photosensitive drum device - Google Patents

Abstract

PURPOSE:To prevent color slurring from occurring in full color copying. CONSTITUTION:A drum shaft 9 and a driving flange 7 supporting the trailing edge of a photosensitive drum 1 are attached to a copying machine main body, and a pawl part 9a which engages with the photosensitive drum 1 and moves it forward when a rack 2 which is freely drawn out from the main body is drawn out is provided in the rack 2, and a front side drum support 18 and a rear side drum support 19 which support the photosensitive drum 1 are provided there. When the rack 2 is drawn out, only the photosensitive drum 1 and a front side flange 15 get out of a drum shaft 9 and the driving flange 7 and drawn out, thereby facilitating exchanging work. Since the photosensitive drum 1 is exchanged in a state where the flange 7 to which rotation driving force is transmitted is attached to the main body, a driving force transmitting system is constructed with small backlash.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive drum device mounted on a black and white / full color copying machine or the like.

[0002]

2. Description of the Related Art In a conventional black-and-white / full-color copying machine, as shown in FIG. 3, a photosensitive drum 51 is assembled to a drum shaft 56 to form a drum unit 50. A front side flange 53 and a rear side flange 5 in which ball bearings 64 are installed at respective center positions are provided at both ends of the photosensitive drum 51.
4 is provided, and the nut 55 is screwed and fastened to the front end of the drum shaft 56 that penetrates through the flanges 53 and 54, whereby the photosensitive drum 51 is sandwiched between the flanges 53 and 54. ing. A cylindrical drum heater 66 arranged inside the photosensitive drum 51 is further attached to the drum shaft 56 in order to heat the photosensitive drum 51 from the inside.

On the other hand, in the main body of the copying machine, there are provided racks 52 which can be put in and taken out along slide guides 63, 63 of a main body frame (not shown), and fixed to the front and rear wall surfaces of the rack 52, respectively. By assembling the front and rear end sides of the drum shaft 56 from above into the front guide 57 and the rear guide 58, the drum unit 50 is assembled into the rack 52.

A rotatable idle shaft 60 extends through the rear wall of the rack 52. A small coupling 61 is provided at the rear end of the idle shaft 60 and a drive gear 59 is provided at the front end. Has been. This drive gear 59 is
In the state where the rack 52 with the drum unit 50 attached thereto is pushed into the main body as described above, the rack 52 meshes with the driven gear 65 attached along the rear flange 54, while the small coupling 61 is The large coupling 62 is connected to a drive unit (not shown) on the main body of the copying machine. As a result, the driving force from the drive unit is transmitted to the photoconductor drum 51 via the idle shaft 60, and the photoconductor drum 51 is rotationally driven. Although not shown, the rack 52 houses a set of process units such as a developing tank, a main charger, and a cleaner around the photosensitive drum 51.

[0005]

However, as described above, in the conventional photoconductor drum device constructed by assembling the photoconductor drum 51 as the drum unit 50 into the rack 52, the replacement work of the photoconductor drum 51 is not required. The problem is that it becomes complicated. That is, in the replacement work in the above configuration, first, the rack 52 is pulled out from the copying machine main body, then the developing tank and the cleaner unit are removed,
It is necessary to remove the drum unit 50 from the rack 52. After that, the nut 55 and the front flange 53 are sequentially removed from the drum shaft 56, and then the photosensitive drum 51 can be removed from the drum shaft 56. In this state,
It can be replaced with a new photosensitive drum. As described above, the removal of the photoconductor drum 51 and the assembling work performed in the reverse order to the above are troublesome, and the drum unit in the state where the photoconductor drum 51 is assembled to the drum shaft 56 is required. When the work of taking out the entire 50 from the rack 52 and assembling it is carried out, this is a considerable weight, and this also causes a drop in workability.

Further, for example, in a full-color copying machine, there is a problem that color shift is likely to occur. That is, in the driving force transmission path for driving the photoconductor drum 51, the photoconductor drum 51 is replaced at two engagement points of the small coupling 61 and the large coupling 62, and the drive gear 59 and the driven gear 65. Since the attachment / detachment is repeated every time, the configuration in which the occlusal accuracy is so high cannot be obtained. Therefore, due to the relatively large backlash at these locations, the rotational position accuracy of the photoconductor drum 51 is not sufficiently ensured, and as a result, the above-mentioned color shift is likely to occur.

[0007]

In order to solve the above problems, a photosensitive drum device of the present invention includes a rack that can be drawn out from the inside of the main body, and a drum shaft that extends in the rack in parallel with the drawing direction. A rotatable flange which is spaced apart from each other along the axial direction of the drum shaft, and a cylindrical photosensitive drum which is supported concentrically with the drum shaft by being sandwiched by these flanges in the axial direction. A photosensitive drum device in which a rotational driving force from the main body side is transmitted to the rear side flange on the rear end side in the drawing direction, and the rear end side of the drum shaft and the rear side flange are attached to the main body. , The rack is provided with an engaging portion that applies forward pushing force to the photoconductor drum when the rack is pulled out, and the photoconductor drum moves forward so that the rear end side is The respective end portions of the photosensitive drum when they are disengaged from the rear side flange and when the front side flange supported by the penetration of the drum shaft is disengaged from the front end portion of the drum shaft, are positioned concentrically with the drum shaft. It is characterized in that front and rear drum supports are provided for substantially maintaining the above and supporting from below.

[0008]

According to the above construction, when the rack is pulled out, the photosensitive drum is moved forward by the engaging portion together with the front flange. As a result, when the rear end side of the photosensitive drum is disengaged from the rear side flange and the front side flange is disengaged from the front end of the drum shaft, the respective end parts of the photosensitive drum substantially maintain their concentric positions with the drum shaft. With the
Both ends are supported by the front and rear drum supports, and the drum is pulled out together with the rack.

On the other hand, a new photosensitive drum is mounted on the front drum support and the rear drum support with the front flange attached to the front end thereof, and then the rack is pushed into the main body by the above-mentioned operation. As described above, since the photosensitive drums mounted on the front side drum support and the rear side drum support are almost maintained in the concentric position with the drum shaft,
With the pushing operation of the rack, the rear end side of the photosensitive drum is in a predetermined assembled state with the rear flange.

As described above, in the above structure, when the rack is pulled out from the main body of the copying machine, only the photosensitive drum and the front side flange are pulled out together with the rack apart from the drum shaft and the rear side flange. That is, the photosensitive drum remains in the rack in a state where it has already been extracted from the drum shaft by the pulling-out operation of the rack. Therefore, the replacement work of the photosensitive drum becomes easy. Also,
As described above, the work of taking out from the rack can be performed by performing the work on the photoconductor drum and the front flange, which are separated from the drum shaft and the drive flange and are relatively lightweight, so that the photoconductor drum can be replaced. Therefore, this also improves the workability of the replacement work as compared with the conventional case.

Furthermore, since the rear flange to which the driving force from the main body side for driving the rotation of the photosensitive drum is transmitted can be replaced with the photosensitive drum, the driving force can be transmitted. It is possible to make the configuration with high occlusal accuracy by further reducing the backlash at the occlusal portion such as the gear train in the path. As a result, the rotational position accuracy of the photoconductor drum can be further increased, so that color misregistration in a full-color copying machine can be further reduced and the image quality can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

In the black-and-white / full-color copying machine constructed by applying the present invention, as shown in FIG. 1, a pair of slide guides extending from the rear frame 3 of the copying machine body forward (to the lower right in the figure). 20 and 20 are provided, and the box-shaped rack 2 having an open upper surface is supported by these slide guides 20 so as to be freely inserted into and taken out from the inside of the copying machine main body.

As shown in FIG. 2, the rear frame 3 has a drive plate 4 on its rear surface (left surface in the figure).
The drive plate 4 is mounted with a flanged bearing 5 into which a rearward projecting portion 7a of a drive flange 7 to be described later is press-fitted.

A cover plate 10 for covering the rear of the bearing 5 is further mounted on the rear side of the drive plate 4, and the rod-shaped drum shaft 9 is attached to the cover plate 10.
The rear end side is fixed. The drum shaft 9 is formed in a rod shape extending from the fixed mounting position to the cover plate 10 to the front side, and penetrates the shaft center hole of the drive flange 7 press-fitted into the bearing 5 in a loosely fitted state. Therefore, the drive flange 7 is rotatable around the drum shaft 9.

The drive flange 7 is prevented from moving rearward because the right end step portion of the rearward projecting portion 7a comes into contact with the inner ring end surface of the bearing 5 from the front side.
On the other hand, a retaining ring 8 is fitted at a position along the right end side end surface of the drive flange 7 on the outer periphery of the drum shaft 9,
The retaining ring 8 prevents the drive flange 7 from being pulled out toward the front side.

The drive flange 7 is provided at a portion between the rear frame 3 and the drive plate 4 with the rear projection 7
The driven gear 7b is provided by forming the driven gear 7b to have a diameter larger than that of a and cutting the outer peripheral portion thereof. A drive force from a drive unit (not shown) provided on the main body of the copying machine is transmitted to the driven gear 7b via the transmission gears 13 and 13, whereby the drive flange 7 is rotationally driven.

Further, a fitting portion 7c having a larger diameter is provided on the front side of the driven flange 7b of the drive flange 7. The photosensitive drum 1 is assembled by externally fitting the rear end side of the photosensitive drum 1 to the outer periphery of the fitting portion 7c. The fitting surface between the outer peripheral surface of the fitting portion 7c and the rear end side inner peripheral surface of the photosensitive drum 1 is formed in a tapered shape.

The rear end of the photosensitive drum 1 is fitted onto the fitting portion 7c of the drive flange 7 as described above, and the front end is provided on the outer periphery of the substantially disk-shaped front flange 15 and the rear end. Similarly, by being externally fitted, the drum shaft 9 is supported concentrically. The front side flange 15 is rotatably supported on the front end side of the drum shaft 9 via a bearing 16. A nut 17 is screwed to the front end of the drum shaft 9 through a through hole in the front wall of the rack 2, and the screw fastening force of the nut 17 presses the front flange 15 rearward via the bearing 16. The outer peripheral surface of the front flange 15 and the inner peripheral surface of the right end of the photosensitive drum 1 fitted onto the outer peripheral surface of the front flange 15 are fitted so that the force acts on the photosensitive drum 1 rearward. The attachment surface is formed in a taper shape. As a result, the fitting portion 7c of the drive flange 7 and the front flange 15 are pushed into both ends of the photosensitive drum 1, and the photosensitive drum 1 is axially sandwiched between the drive flange 7 and the front flange 15. It has a structure.

A cylindrical drum heater 14 located inside the photosensitive drum 1 for heating the photosensitive drum 1 to a predetermined temperature is coaxially attached to the drum shaft 9.

On the other hand, on the front wall and the rear wall of the rack 2, the outer periphery of the photoconductor drum 1 is supported so that both ends of the photoconductor drum 1 can be supported from below when the rack 2 is pulled out, which will be described later. A front side drum support 18 and a rear side drum support 19 having an arcuate cross section are provided. At the rear end of the rear drum support 19, a claw portion 19a that is further raised is formed. The height dimension of the claw portion 19a is set according to the thickness dimension of the rear end surface of the photosensitive drum 1 fitted to the drive flange 7 so as not to reach the fitting portion 7c of the drive flange 7. ing.

The front side drum support 18 and the rear side drum support 19 are provided at positions where a slight gap is formed between the front side drum support 18 and the rear side drum support 19 when the photosensitive drum 1 is assembled as described above. As a result, the rotation of the photosensitive drum 1 is not hindered. Inside the rack 2, outside the photosensitive drum 1, a set of process units such as a developing tank and a main charger / cleaner (not shown) are housed.

The procedure for replacing the photosensitive drum 1 in the above-mentioned structure will be described below.

When replacing the photosensitive drum 1, first,
The nut 17 screwed to the front end of the drum shaft 9 is removed. As a result, the rack 2 can be pulled out to the front side from the inside of the copying machine main body. When the rack 2 is pulled out, the claw portion 19a of the rear drum support 19 is caught on the rear end surface of the photoconductor drum 1, whereby the pullout operation of the rack 2 is performed. Is the front flange 15 fitted to the front end of the
At the same time, it is pushed forward. As a result, the rear end side of the photosensitive drum 1 is disengaged from the fitting portion 7c of the drive flange 7.
At this time, the rear end side of the photosensitive drum 1 descends within a slight clearance range with the rear drum support 19 and is supported by the rear drum support 19 from the lower side. , And the rack 2 are pulled forward.

When the front flange 15 comes off from the front end of the drum shaft 9 in the process of pulling out the rack 2, the front end side of the photosensitive drum 1 becomes the front drum support 1.
8 and is supported by the front side drum support 18 from the lower side, and thus the horizontal state in which both ends are supported by the front side drum support 18 and the rear side drum support 19 is maintained. Further, it will be pulled out forward together with the rack 2.

Then, with the rear wall of the rack 2 pulled out until the front end of the drum shaft 9 is located, the process unit located above the photosensitive drum 1 is removed to remove the photosensitive drum 1. Take out from inside the rack 2. At this time, since only the front side flange 15 is attached to the photoconductor drum 1, the photoconductor drum 1 is relatively lightweight, and therefore, the photoconductor drum 1 can be easily taken out.

Thereafter, the front side flange 15 is pulled out from the photosensitive drum 1 and the photosensitive drum 1 is replaced. When mounting the replaced new photoconductor drum 1, the front side flange 15 is pushed into the front end portion of the new photoconductor drum 1 and fitted. Then, the photosensitive drum 1 is placed on the front drum support 18 and the rear drum support 19 of the rack 2. After assembling the process unit, the rack 2 is pushed into the main body of the copying machine. In the process of this pushing operation, the drum shaft 9 is inserted into the photosensitive drum 1 placed on the front drum support 18 and the rear drum support 19 as described above, and the front end of the drum shaft 9 is further inserted. Penetrates through the bearing 16 of the front flange 15. As a result, the front end side of the photosensitive drum 1 is lifted slightly upward from the front side drum support 18,
From the support state by the front side drum support 18 to the drum shaft 9
Changes to the support state. Thereafter, the front end of the drum shaft 9 is further projected forward from the front wall of the rack 2, while the tapered fitting portion 7c of the drive flange 7 is fitted to the rear end of the photosensitive drum 1. It becomes a state.

After the pushing operation of the rack 2 as described above is completed, the nut 17 is screwed onto the front end of the drum shaft 9 through the through hole in the front wall of the rack 2. By this screwing operation, as described above, the photosensitive drum 1
Is pushed backwards. As a result, the rear end side of the photosensitive drum 1 is slightly lifted along the tapered surface of the fitting portion 7c of the drive flange 7. As a result, the rear end side of the photosensitive drum 1 is slightly separated from the rear drum support 19,
The entire circumference of the fitting portion 7c is fitted into the fitting portion 7c, and the driving flange 7 and the front flange 15 are assembled in the axial direction so that the photosensitive drum 1 is replaced. ..

In the assembled state as described above, at the time of copying, the driving force from the driving motor in the driving unit (not shown) provided on the copying machine body side is transmitted by the transmission gears 13 and 13.
Is transmitted to the driven gear 7b of the drive flange 7 via the drive shaft 7, and as a result, the photosensitive drum 1 is rotationally driven together with the drive flange 7 and the front side flange 15.

As described above, in the photoconductor drum device of this embodiment, when the rack 2 is pulled out from the main body of the copying machine, only the photoconductor drum 1 and the front side flange 15 have the drum shaft 9 and the drive flange 7. Is pulled out together with the rack 2. That is, the photosensitive drum 1 is present in the rack 2 in a state where it is already pulled out from the drum shaft 9 by the pulling-out operation of the rack 2. Therefore, when replacing the photoconductor drum 1, only the removal of the front side flange 15 and the attachment work to the new photoconductor drum 1 are performed so that when the rack 2 is pushed in, the drum shaft 9 is automatically assembled. The replacement work can be easily performed.

Further, as described above, by separating from the drum shaft 9 to which the drum heater 14 is attached and the drive flange 7, the work of taking out from the rack 2 becomes relatively lightweight. And front flange 1
Since the photoconductor drum 1 can be exchanged by performing the operation for No. 5, the workability of the exchange work is also improved as compared with the conventional case.

Further, in the above-described embodiment, since the photoconductor drum 1 can be replaced while the gear train for rotating the photoconductor drum 1 maintains the engaged state, It is possible to configure as a driving force transmission system with high occlusal accuracy with a smaller backlash. As a result, the rotational position accuracy of the photoconductor drum 1 can be further increased, so that the color shift in the full-color copying machine can be further reduced and the image quality can be improved.

In the above embodiment, the drum shaft 9
The drive flange 7 and the drive flange 7 are individually supported by the drive plate 4 and the cover plate 10 which are sequentially attached to the rear frame 3. For example, the drive flange is attached to the drum shaft 9 fixed to the rear frame 3. It is possible to rotatably support 7 through bearings and to provide retaining rings for restricting the movement along the drum shaft 9 in front of and behind the drive flange 7, for example. However, by adopting the above-described individual support structure so that the drum shaft 9 supports only the front side flange 15 of the photosensitive drum 1, the load acting on the drum shaft 9 is reduced, and as a result, It is not necessary to make the diameter of the drum shaft 9 fixed by the cantilever structure on the end side excessively large or to make the structure of the fixing portion large, so that the structure can be simplified and downsized.

Further, in the above-mentioned embodiment, an example in which the engaging portion for moving the photosensitive drum 1 forward when the rack 2 is pulled out is constituted by the claw portion 19a of the rear drum support 19 has been described. The front side flange 15 is fixed to the front end surface of the photosensitive drum 1 with a screw, and a flange-shaped portion slightly larger than the outer periphery of the photosensitive drum 1 is provided on the front side flange 15. Other configurations, such as being provided on the side, are also possible.

[0035]

As described above, in the photoconductor drum device of the present invention, the rear end side and the rear side flange of the drum shaft are attached to the main body, while the rack which can be drawn out from the main body is equipped with this rack. At the time of pulling out, the photosensitive drum whose both ends are supported by the front and rear flanges is provided with an engaging portion for applying a pushing force to the front, and the photosensitive drum is moved forward so that the rear end side is from the rear flange. When it comes off
And, each end of the photosensitive drum when the front side flange supported by the drum shaft penetrating is disengaged from the front end of the drum shaft, from the lower side while substantially maintaining the concentric position with the drum shaft. In this configuration, front and rear drum supports that support the drum support are provided.

As a result, when the rack is pulled out from the inside of the main body, the photosensitive drum has already been removed from the drum shaft, and the replacement of the photosensitive drum requires removal of the front flange and a new photosensitive drum. After the mounting work is performed, the photosensitive drums can be placed on the front and rear drum supports and the rack can be pushed into the main body. Therefore, the replacement work is easier than the conventional one, and the replacement work can be performed easily. Further, as described above, since the work of taking out from the rack is performed on the relatively lightweight photosensitive drum and the front side flange which are separated from the drum shaft and the driving flange,
This also improves the workability of the replacement work as compared with the conventional one. Further, since the rear side flange to which the driving force from the main body side is transmitted can be replaced with the photosensitive drum with the rear side flange being attached to the main body side, backlash at the engagement position such as the gear train in the driving force transmission path is further improved. It is possible to make the bite highly accurate. As a result, the rotational position accuracy of the photosensitive drum can be further increased,
For example, the color shift in a full-color copying machine is further reduced, and the image quality can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a photosensitive drum device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the photosensitive drum device.

FIG. 3 is a perspective view showing a conventional photosensitive drum device.

[Explanation of symbols]

 1 Photoreceptor Drum 2 Rack 7 Drive Flange (Rear Side Flange) 9 Drum Shaft 15 Front Side Flange 18 Front Side Drum Support 19 Rear Side Drum Support 19a Claw (Hooking Part)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takashi Kubo 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (1)

Claim: What is claimed is: 1. A rack which can be drawn out from the main body, a drum shaft which extends in the rack in parallel with the drawing direction, and which are located apart from each other along the axial direction of the drum shaft. A rotatable photosensitive drum and a cylindrical photosensitive drum supported concentrically with the drum shaft by being sandwiched in the axial direction by these flanges are provided, and at the rear side flange on the rear end side in the drawing direction. In a photoconductor drum device to which a rotational driving force is transmitted from a main body side, a rear end side of the drum shaft and a rear flange are attached to the main body, while the photoconductor is attached to the rack when the rack is pulled out. A hook is provided on the drum to apply a pushing force to the front, and when the photosensitive drum moves forward and the rear end side is disengaged from the rear flange, and when the drum shaft is Front end and rear end that respectively support the respective end portions of the photosensitive drum when the front flanges supported by passing through the front end portion of the drum shaft deviate from the lower side while substantially maintaining the concentric position with the drum shaft. A photoconductor drum device, which is provided with a side drum support.