JP3854762B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as an electrophotographic or electrostatic recording type copying machine or printer.
[0002]
[Prior art]
Among the above image forming apparatuses, color image forming apparatuses such as color copiers and color printers will be taken up and the prior art will be described below.
[0003]
Among the color image forming apparatus, the photosensitive drum, what configuration adopting an intermediate transfer belt, yellow, magenta, cyan, process unit for forming a toner image of black four colors are installed, each process The photosensitive drums of the unit are in contact with the intermediate transfer belt as shown in the figure. Further, each of the process units, by withdrawing from the image forming apparatus main body in front, and has a replacement or configured to be maintained as a consumable.
[0004]
The intermediate transfer belt unit includes the intermediate transfer belt drive roller, a tension roller, a secondary transfer to the opposite roller thus is stretched by the primary transfer roller across the intermediate transfer belt is arranged on the opposite side of the photosensitive drum It is configured. Further, by operating a separation lever installed in the image forming apparatus main body, the intermediate transfer belt unit support portion can be moved up and down to move the intermediate transfer belt unit up and down. Therefore, the intermediate transfer belt unit is configured to be positioning relative Therefore the image forming apparatus main body in the positioning roller.
[0005]
Next, an image forming operation will be briefly described.
[0006]
The image forming operation, first an electrostatic latent image formed on the photosensitive drum and thus developed into each color developing device, transfer (primary color toner images which are the visualized sequentially superposed on an intermediate transfer belt Transfer) to form a full-color image on the intermediate transfer belt. On the other hand , the transfer material is conveyed in accordance with the position of the image on the intermediate transfer belt . Then , the transfer material is sandwiched between the secondary transfer roller and the intermediate transfer belt, and the full color image on the intermediate transfer belt is collectively transferred (secondary transfer) to the transfer material. When the transfer to the transfer material (secondary transfer) is completed, the transfer material which full-color image has been transferred is then to a fixing device arranged downstream of the secondary transfer portion thus fixing the image.
[0007]
[Problems to be solved by the invention]
However, in the conventional example, the secondary transfer unit may be carried out a contact-separation operation for the intermediate transfer belt, for purposes such as shock reduction at the time of contact or away from the secondary transfer roller during image formation The position of the secondary transfer portion at the time of separation needs to be as close to the secondary transfer counter roller as possible . However, it is required to create a space around the secondary transfer portion during jam processing.
[0008]
Accordingly, an object of the present invention is to reduce the jam usability improvements upon between the transfer conveyance unit and the intermediate transfer belt having a secondary transfer portion.
[0009]
[Means for Solving the Problems]
To achieve the above object, a typical configuration of the present invention includes an image carrier that carries a toner image, an intermediate transfer member that receives the transfer of the toner image from the image carrier, and an abutting contact with the intermediate transfer member. A transfer means for transferring a toner image on the intermediate transfer body to a transfer material; an intermediate transfer body unit having the intermediate transfer body; and a transfer transport unit having the transfer means. In the image forming apparatus in which the transfer unit can be brought into contact with and separated from the intermediate transfer body on the transfer conveyance unit while being positioned and supported with respect to the intermediate transfer body unit. the transfer conveying unit is swingable about an axis, positioning supports the transfer conveyance unit image formation in a state possible for the intermediate transfer unit, and the intermediate transfer The distance between the intermediate transfer member and the transfer unit when the support is released and the transfer conveyance unit is separated from the intermediate transfer member unit is released. , the transfer means much larger than the distance away from the intermediate transfer member on the transfer conveyance unit, the transfer conveying unit, the conveying the transfer material to the contact position where the intermediate transfer body and the transfer means abutted It is characterized by having a registration roller .
[0010]
According to the above configuration, it is possible to improve the usability during the jam processing between the transfer conveyance unit including the transfer unit and the image carrier.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an image forming apparatus to which the present invention is applied will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a configuration diagram of a main part of an image forming apparatus according to the present embodiment. First, the schematic configuration and operation of the main part of the image forming apparatus will be briefly described with reference to FIG. 1, and then the positioning configuration of the intermediate transfer belt unit 3 and the transfer conveyance unit 14, which is a feature of the present invention, will be described.
[0013]
First, a schematic configuration of the main part of the image forming apparatus will be described below by taking up a color image forming apparatus represented by a color copying machine or a color printer.
[0014]
As shown in FIG. 1, a color image forming apparatus that employs a photosensitive drum as an image carrier and an intermediate transfer belt is a process unit for forming toner images of four colors of yellow, magenta, cyan, and black. 1 is installed, and the photosensitive drum 2 of each process unit 1 is in contact with the intermediate transfer belt 4 as shown in the figure. Each process unit 1 can be replaced or maintained as a consumable by being pulled out from the image forming apparatus main body.
[0015]
In the intermediate transfer belt unit 3 as an intermediate transfer member, an intermediate transfer belt 4 is stretched by a driving roller 6, a tension roller 7, and a secondary transfer counter roller 9, and the intermediate transfer belt is opposed to each photosensitive drum 2. A primary transfer roller 5 is arranged with 4 interposed therebetween. Further, by operating a separation lever 10 provided in the image forming apparatus main body, the intermediate transfer belt unit support portion 12 can be moved up and down to move the intermediate transfer belt unit 3 up and down. Accordingly, the intermediate transfer belt unit 3 is positioned with respect to the image forming apparatus main body by the positioning roller 11.
[0016]
The transfer / conveying unit 14 as a transfer / conveying unit has a secondary transfer oscillating unit 16 including a secondary transfer roller 18 as a secondary transferring unit and a conveying guide 22 before the secondary transfer, and the secondary transfer oscillating unit 16 is swingable by a swing cam 19 around a secondary transfer swing shaft 17. Further, the transfer conveyance unit 14 is provided with a registration roller 23 for preventing the transfer material 25 from being skewed and synchronizing with the image, and a charge removal needle 24 for performing charge removal of the transfer material after the secondary transfer. .
[0017]
Further, the transfer transport unit 14 can swing around the transfer transport unit swinging shaft 15, and the positioning structure of the transfer transport unit 14 with respect to the intermediate transfer belt unit 3 will be described in detail later. Describe.
[0018]
Next, an image forming operation will be briefly described.
[0019]
As an image forming operation, first, an electrostatic latent image formed on the photosensitive drum 2 is visualized by each color developing device (not shown), and each visualized color toner image is sequentially transferred onto the intermediate transfer belt 4. Are transferred (primary transfer) to form a full-color image on the intermediate transfer belt 4. On the other hand, the transfer material 25 is conveyed by the registration roller 23 in accordance with the position of the image on the intermediate transfer belt 4. At this time, the swing cam 19 rotates, the secondary transfer swing portion 16 swings toward the intermediate transfer belt 4, and the secondary transfer roller 18 contacts the intermediate transfer belt 4. Then, the transfer material 25 conveyed through the conveyance guide 22 is sandwiched between the secondary transfer roller 18 and the intermediate transfer belt 4, and the full color image on the intermediate transfer belt 4 is collectively transferred to the transfer material 25. Transfer (secondary transfer). When the transfer to the transfer material 25 (secondary transfer) is completed, the swing cam 19 rotates again, the secondary transfer swing portion 16 is lowered, and the secondary transfer roller 18 is separated from the intermediate transfer belt 4. Thereafter, the transfer material 25 onto which the full-color image has been transferred is fixed by a fixing device (not shown) disposed downstream of the secondary transfer portion.
[0020]
Next, a positioning configuration of the intermediate transfer belt unit 3 and the transfer conveyance unit 14 which is a configuration unique to the present invention will be described.
[0021]
As described above, the transfer / conveyance unit 14 can swing around the transfer / conveyance unit swinging shaft 15. The transfer / conveyance unit 14 is supported by the intermediate transfer belt unit 3. The hook 13 serving as the supporting means holds the positioning shaft 21 installed in the transfer conveyance unit 14 and is supported in a state where image formation is possible as shown in FIG.
[0022]
As shown in FIG. 5, the hook 13 can be released from the positioning shaft 21 by operating a release lever 20 that can be rotated about the positioning shaft 21. Can be greatly separated from the intermediate transfer belt unit 3. Conversely, when setting the transfer conveyance unit 14 to the installation position for image formation, the user lifts the transfer conveyance unit 14 and pushes the hook 13 away from the positioning shaft 21 and raises it to the installation position, and then the tension spring. What is necessary is just to lift the transfer conveyance unit 14 until the hook returns at 26.
[0023]
Further, when the secondary transfer roller 18 does not perform an image forming operation or when the transfer material is not conveyed to the secondary transfer portion for some reason, the roller is contaminated by the toner on the intermediate transfer belt 4. For the purpose of prevention, the swing cam 19 is rotated halfway, the secondary transfer swing portion 16 is lowered, and the secondary transfer roller 18 is separated from the intermediate transfer belt 4 (see FIG. 2).
[0024]
In this embodiment, since the hook 13 is attached to the intermediate transfer belt unit 3, the transfer conveyance unit 14 supported by the hook 13 can obtain high positional accuracy with respect to the intermediate transfer belt unit 3. . Thereby, the position of the transfer point (nip) between the secondary transfer roller 18 and the secondary transfer counter roller 9 and the contact pressure of the nip can be obtained stably. In addition, the position accuracy of the conveyance guide 22 and the neutralization needle 24 after secondary transfer with respect to the nip position can be obtained with higher accuracy than before, so an image forming device that can stably output high-quality images has been realized. Is done.
[0025]
Also, by installing the hook 13 to the intermediate transfer belt unit 3, such as replacement of the process unit 1, when separating the intermediate transfer belt 4 from the photosensitive drum 2, an intermediate transferring the transfer conveyance unit 14 above the belt unit 3 Even if the operation of retreating from the photosensitive drum 2 is not performed, only the operation of separating the intermediate transfer belt unit 3 from the photosensitive drum 2 by operating the separation lever 10 can simultaneously move the transfer conveyance unit 14 to the retreat position. (See FIG. 3).
[0026]
Further, after the process unit 1 is replaced, only the operation of operating the separation lever 10 to return the intermediate transfer belt unit 3 to the contact position with respect to the photosensitive drum 2, and at the same time, the transfer conveyance unit 14 is set to the image forming operation position. Set.
[0027]
Incidentally, at the time of the jam processing, by operating the release lever 20, by releasing the hook 13, Ru to oscillate the transfer conveyance unit 14 in a direction about the pivot shaft 15 away from the intermediate transfer belt unit 3. As a result, the secondary transfer roller 18 is separated from the intermediate transfer belt 4 more greatly than the secondary transfer oscillating portion 16 is lowered only on the transfer conveyance unit 14 , and a space can be created around the secondary transfer portion (FIG. 4).
[0028]
With the above mechanism, the positioning accuracy of the transfer / conveying unit 14 having the secondary transfer portion with respect to the intermediate transfer belt 4 is improved, so that the quality of the output image can be improved and the photosensitive drum 2 (process unit 1) is replaced. The usability can be improved.
[0029]
In the present embodiment, the case where the hook 13 as the support means is installed in the intermediate transfer belt unit 3 as the intermediate transfer member has been described. However, the present invention is not limited to this, and the hook is not limited thereto. Even if 13 is installed on the side of the transfer conveyance unit 14 as a transfer conveyance means, the same effect can be obtained.
[0030]
The transfer / conveyance unit 14 can swing around the transfer / conveyance unit swinging shaft 15. The positioning structure of the transfer / conveyance unit 14 with respect to the intermediate transfer belt unit 3 is shown in FIGS. It may be as shown in FIG. In this configuration, the transfer conveyance unit 14 is supported in a horizontal state as shown in FIG. 6 by the locking means 27 installed in the image forming apparatus main body during image formation. Then, during jam processing or when the intermediate transfer belt 4 is separated from the photosensitive drum 2 (exchange of the photosensitive drum, etc.), the transfer means 14 is centered on the swing shaft 15 by releasing the lock means 27. As in the above-described embodiment , a space can be created around the secondary transfer portion (see FIG. 7).
[0031]
In this configuration, in order for the user to replace the process unit 1, first, the lock means 27 is operated to release the transfer / conveyance unit 14 (see FIG. 7), and secondly, the separation lever 10 is operated. the operation such as separating the intermediate transfer belt 4 (see FIG. 8), Ru must perform always in this order.
[0032]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a high jam handling property while suppressing a shock at the time of contact and separation.
[Brief description of the drawings]
FIG. 1 is a simplified diagram showing a main configuration of an image forming apparatus according to the present invention (when a secondary transfer roller is in contact).
FIG. 2 is a simplified diagram showing the main configuration of the image forming apparatus according to the present invention (when the secondary transfer roller is separated);
FIG. 3 is a simplified diagram showing the main configuration of an image forming apparatus according to the present invention (when a photosensitive drum is replaced).
FIG. 4 is a simplified diagram showing the main configuration of an image forming apparatus according to the present invention (during jam processing).
FIG. 5 is a simplified diagram showing a method for releasing a transfer conveyance unit of an image forming apparatus according to the present invention . FIG. 6 is a simplified diagram showing a transfer conveyance unit support method according to the present invention . Simplified diagram showing support method (when jam processing)
FIG. 8 is a simplified diagram showing a method for supporting a transfer conveyance unit according to the present invention (when a photosensitive drum is replaced).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Process unit 2 ... Photoconductor drum 3 ... Intermediate transfer belt unit 4 ... Intermediate transfer belt 5 ... Primary transfer roller 6 ... Drive roller 7 ... Tension roller 9 ... Secondary transfer counter roller
10 ... Separation lever
11… Positioning roller
12… Intermediate transfer belt unit support
13… Hook
14 Transfer transfer unit
15 Transfer shaft swing axis
16… Secondary transfer swinging part
17… Secondary transfer swing axis
18 ... Secondary transfer roller
19… Oscillating cam
20… Release lever
21… Positioning axis
22… Conveyance guide
23… Registration roller
24 ... Static elimination needle
25… Transfer material
26… Tension spring
27… Locking means

Claims (2)

An image carrier that carries a toner image, an intermediate transfer member that receives the transfer of the toner image from the image carrier, and a transfer unit that contacts the intermediate transfer member and transfers the toner image on the intermediate transfer member to a transfer material And an intermediate transfer body unit having the intermediate transfer body, and a transfer conveyance unit having the transfer means, and in a state where the transfer conveyance unit is positioned and supported with respect to the intermediate transfer body unit, In the image forming apparatus, the transfer unit can be brought into contact with and separated from the intermediate transfer member on the transfer conveyance unit.
The transfer conveyance unit is swingable about an axis, and positions and supports the transfer conveyance unit so that an image can be formed with respect to the intermediate transfer body unit, and is separated from the intermediate transfer body. The distance between the intermediate transfer body and the transfer means when the support is released and the transfer conveyance unit is separated from the intermediate transfer body unit is the transfer means. There much larger than the distance away from the intermediate transfer member on the transfer conveyance unit, the transfer conveyance unit, a registration roller for the conveying the transfer material to the contact position where the intermediate transfer body and the transfer means abutted An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the transfer conveyance unit includes a guide portion that guides a transfer material to the contact position.

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