JP2002258635A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a transfer roller from being erroneously attached. SOLUTION: This image forming device is equipped with a transfer device 11 transferring a toner image formed on an image carrier to transfer material, and the device 11 is constituted by installing a transfer roller provided to be opposed to the image carrier, a bearing 3 bearing the rotary shaft of the transfer roller and a transfer material guide member 1 guiding the transfer material toward space between the image carrier and the transfer roller in a frame 4, then, an aperture is formed on the bearing 3 so as to attach/detach the transfer roller. The device is equipped with a stopper 42 making the member 1 stand still at a position where the transfer roller is prevented from being erroneously installed when the member 1 is operated to an exchange position where the transfer roller is exchanged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to an image forming apparatus such as a laser beam printer, an LED printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a means using a transfer roller as a means for transferring a toner image formed and carried on a photosensitive member surface (image bearing member surface) to a transfer material is generally used. It is. The transfer roller is composed of a cored bar and a conductive elastic layer such as conductive rubber or sponge formed concentrically with the core. Let me touch
When the transfer material passes through the nip portion, a bias having a polarity opposite to the charging polarity of the toner image is applied to the transfer roller, so that the toner image on the photoconductor surface is transferred to the transfer material surface.

The conductive elastic layer of the transfer roller is durably fatigued by being pressed against the photosensitive member, the surface is worn by the difference in linear velocity between the photosensitive member and the transfer roller, and the toner and Since the characteristics change due to the adhesion of paper dust or the like, the transfer performance deteriorates and the image quality deteriorates. For this reason, the transfer roller has a built-in structure that is detachable from the image forming apparatus so that the deteriorated transfer roller can be replaced with a new one in a timely manner.

In general, there is a type in which the upper side of a bearing hole of a bearing that freely supports a rotation shaft of a transfer roller is opened so that the transfer roller can be detached from the upper side of the bearing. . However, when the transfer roller is actually taken out, it is difficult to grasp the transfer roller due to the presence of the transfer guide plate and the like disposed close to the upstream and downstream sides of the transfer roller. In addition, the upper opening of the bearing member is often narrower in opening width than the diameter of the core metal of the transfer roller in order to prevent the transfer roller from easily coming off the transfer bearing. Would.

Therefore, there has been proposed a transfer apparatus characterized in that when the state of the transfer material guide position of the transfer guide is changed, the transfer roller can be removed from the transfer bearing by the conversion force. Such a transfer device is shown in FIGS. In the drawing, reference numeral 101 denotes a transfer guide for guiding a transfer material to a transfer position, 102 denotes a transfer roller composed of a cored bar and a conductive elastic body, 103 denotes a transfer bearing for receiving a transfer roller shaft, and 105 denotes a transfer roller 2 to the photosensitive member Transfer bearing 10
3 is an elastic member that urges through the transfer member 3, 106 is a charge removing member that removes charge from the transfer material after transfer, and 107 is a charge removing needle and the transfer roller 10.
A static elimination needle cover 104 for insulating 2 is a frame for installing these components.

[0006]

However, as shown in FIGS. 6 to 8, means for opening and closing the transfer guide 101 when exchanging the transfer roller 102 is used when the visibility of the transfer portion is poor. In many cases, the position shown in FIG. 8A is an appropriate setting position of the transfer roller 102. However, if an exchanger mistakenly attaches the transfer roller 102 to an inappropriate position shown in FIG. 8B, Problems such as the inability to operate the transfer guide 101 and damage to components due to excessive operation occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of preventing a transfer roller from being erroneously attached.

[0008]

According to a first aspect of the present invention, there is provided a transfer device for transferring a toner image formed on an image carrier to a transfer material. A transfer roller provided opposite to the image carrier, a bearing for receiving a rotation shaft of the transfer roller, and a transfer material guide member for guiding a transfer material between the image carrier and the transfer roller; When the transfer material guide member is moved to a replacement position for replacing the transfer roller in an image forming apparatus in which an opening is formed in the bearing so that the transfer roller is detachable, the transfer roller is A stopper is provided for stopping the transfer material guide member at a position where the transfer material guide member is prevented from being erroneously installed.

According to the first aspect of the present invention,
Even if the transfer roller is installed at an incorrect position, the transfer guide can be operated, and the transfer roller can be easily installed again.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a guide means for automatically guiding a transfer roller installed at a wrong position to an appropriate position. It is characterized by the following.

According to the second aspect of the present invention,
The same operation and effect as the invention described in claim 1 can be obtained, and even if the transfer roller is installed at an incorrect position, the transfer roller is automatically guided to the appropriate position by being guided by the guide means. Is done.

According to a third aspect of the present invention, in the second aspect of the invention, when the transfer roller moves to an appropriate installation position, the elastic portion of the transfer roller contacts the frame. A contact preventing means for preventing the

According to the invention described in claim 3,
The same operation and effect as those of the first and second aspects can be obtained, and the elastic portion of the transfer roller is prevented from hitting the frame and being damaged when the transfer roller automatically moves. Can be.

[0014]

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

FIG. 5 shows a printer 71 as an image forming apparatus to which the present invention is applied. As shown in the drawing, the printer 71 includes a photoconductor 75 that is an image carrier,
Around the photoreceptor 75, a charging device 77 for charging the photoreceptor 75, a writing device 73 for writing an electrostatic latent image corresponding to a document image on the charged photoreceptor 75, and an electrostatic latent image on the photoreceptor 75 A developing device 79 for developing as a toner image; a transfer device 11 for transferring the toner image of the photoconductor 75 to a sheet (transfer material) 89 fed from a sheet feeding device 87; Fixing device 95 for fixing toner and fixing device 9
5, a paper output tray 97 for stacking paper 89 on which the toner image has been fixed.

FIG. 1 shows a first embodiment of a transfer device 11. As shown in FIG. 1A, the transfer device 1
1 is a transfer roller 2 composed of a cored bar and a conductive elastic body
(See FIG. 5) and a bearing 3 for receiving the rotation shaft of the transfer roller 2.
And an elastic member (not shown) for urging the transfer roller 2 toward the photosensitive member 75 via the bearing 3, and a transfer guide (transfer material guide) for guiding the paper 89 between the photosensitive member 75 and the transfer roller 2 (transfer position). 1) and a frame 4 for installing these components. The bearing 3 has a substantially U-shape whose upper end is open.

In the present embodiment, when the transfer guide 1 is converted (when the transfer guide 1 is operated to the exchange position for exchanging the transfer roller 2), the snap fit projection 21 of the transfer guide 1 is moved to the frame 4 At the rising portion 41. Therefore, unless the force is applied, the state shown in FIG. 7 does not occur. In this embodiment,
As shown in FIG. 1B, the lower portion of the transfer guide 1 is hooked on the projection 42 of the frame 4.
Therefore, the vehicle stops at the state shown in FIG. 1 without being brought into the state shown in FIG. That is, the projection 42 constitutes a stopper that stops the transfer guide 1 at a position where the transfer roller 2 is prevented from being erroneously installed. With such a configuration, even if the transfer roller 2 is installed at an incorrect position, the transfer guide 1 can be operated, and the transfer roller 2 can be easily installed again.

FIG. 2 shows a second embodiment of the present invention. In the present embodiment, as clearly shown in FIG. 2B, when the transfer guide 1 is converted, the protrusion 22 of the snap fit of the transfer guide 1 is
1 protrusion 41a, but a snap-fit protrusion 2
3 cannot exceed the protrusion 41 a of the rising portion 41 of the frame 4. Therefore, the vehicle does not enter the state shown in FIG. 8 but stays still in the state shown in FIG. That is, the protrusions 23, 41a
Constitutes a stopper for stopping the transfer guide 1 at a position where the transfer roller 2 is prevented from being erroneously installed. With such a configuration, even if the transfer roller 2 is installed at an incorrect position, the transfer guide 1 can be operated, and the transfer roller 2 can be easily installed again.

FIGS. 3 and 4 show a third embodiment of the present invention. In the present embodiment, a rib 43 having an inclination is provided on the frame 4 supporting the bearing 3 so that the bearing 3 is located downstream. As a result, the transfer roller 2 placed on the rib 43 rolls toward the bearing 3 as shown by an arrow C in FIG. That is, the rib 4
Numeral 3 constitutes guide means for automatically guiding the transfer roller 2 installed at an incorrect position to an appropriate position. With such a configuration, even if the transfer roller 2 is installed at an incorrect position, the transfer roller 2 automatically moves and is installed at an appropriate position.

In this embodiment, the rib 43 is provided on the core 25 of the transfer roller 2 (see FIG. 3B) composed of the core 25 and the conductive elastic body (elastic part) 24. The height h of the rib 43 from the frame 4 is larger than the width w of the elastic portion 24 of the transfer roller 2.
Therefore, when the transfer roller 2 automatically moves, the elastic portion 24 of the transfer roller 2 can be prevented from contacting the frame 4 and being damaged. That is, the rib 43 also functions as a contact prevention unit that prevents the elastic portion 24 of the transfer roller 2 from contacting the frame 4 when the transfer roller 2 moves to an appropriate installation position. Note that in FIG.
Is a static elimination member that is a static elimination needle that neutralizes the paper 89 after the transfer;
Reference numeral 7 denotes a static elimination needle cover for insulating the static elimination needle 6 and the transfer roller 2 from each other.

[0021]

According to the first aspect of the present invention, the transfer guide can be operated even if the transfer roller is installed at an incorrect position, and the transfer roller can be easily installed again. According to the second aspect of the invention, the same operation and effect as those of the first aspect of the invention can be obtained, and even if the transfer roller is installed at an incorrect position, the transfer roller is provided with the guide means. Will be automatically installed at the appropriate location. According to the invention described in claim 3,
The same operation and effect as those of the first and second aspects can be obtained, and the elastic portion of the transfer roller is prevented from hitting the frame and being damaged when the transfer roller automatically moves. Can be.

[Brief description of the drawings]

FIG. 1A is a side view of a transfer device according to a first embodiment of the present invention, and FIG. 1B is an enlarged view of a stopper structure between a transfer guide and a frame in FIG.

FIG. 2A is a side view of a transfer device according to a second embodiment of the present invention, and FIG. 2B is an enlarged view of a stopper structure between a transfer guide and a frame in FIG.

FIG. 3A is a side view of a transfer device according to a third embodiment of the present invention, and FIG. 3B is a front view of a transfer roller.

FIG. 4 is a perspective view of the transfer device of FIG. 3;

FIG. 5 is a schematic configuration diagram of an image forming apparatus to which the present invention is applied.

FIG. 6 is a perspective view of a conventional transfer device.

FIG. 7 is a side view of the transfer device of FIG. 6;

8 is a side view showing a state in which the transfer guide is operated from the state of FIG. 7 to a replacement position for replacing the transfer roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transfer guide (transfer material guide member) 2 Transfer roller 3 Bearing 4 Frame 11 Transfer device 42 Projection (stopper) 43 Rib (guide means, contact prevention means) 71 Image forming apparatus 75 Photoconductor (image carrier)

Claims (3)

[Claims] A transfer device configured to transfer a toner image formed on the image carrier to a transfer material, wherein the transfer device receives a transfer roller provided facing the image carrier and a rotation shaft of the transfer roller. A bearing and a transfer material guide member for guiding the transfer material between the image carrier and the transfer roller are provided on the frame, and the bearing has an opening formed to allow the transfer roller to be attached and detached. The image forming apparatus includes a stopper that stops the transfer material guide member at a position that prevents the transfer roller from being erroneously installed when the transfer material guide member is operated to a replacement position for replacing the transfer roller. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, further comprising guide means for automatically guiding a transfer roller installed at a wrong position to an appropriate position. 3. The image forming apparatus according to claim 2, further comprising contact prevention means for preventing the elastic portion of the transfer roller from contacting the frame when the transfer roller moves to an appropriate installation position. Image forming apparatus.