JP2002156008A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device wherein the structure is simplified by eliminating a frame for retreating a transferring means from an image supporting body or an intermediate transferring means and the device constitution is simplified by reducing parts to which driving force is to be transmitted. SOLUTION: In order to attain the purpose, in a representative constitution of the image forming device, a driving mechanism comprising a first gear to which a driving force is transmitted from a first rotating body, a second gear engaging with the first gear, and a second rotating body to which a driving force is transmitted from the second gear, is characterized in that the second rotating body is capable of attaching and detaching the second gear to and from the first rotating body at the rotation center, and a driving force is transmitted to the second rotating body from the second gear when the second rotating body is detached from the first rotating body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for transferring an image formed on an image carrier, an intermediate transfer member or the like to a recording medium to form an image.

[0002]

2. Description of the Related Art The configuration of a conventional image forming apparatus will be described with reference to FIGS. The image forming apparatus shown in FIG. 7 forms a latent image on the image carrier 201 in the process cartridge 200 by the latent image forming unit 100. The latent image is developed by the developing units 501 to 504 of each color rotated by the developing unit switching mechanism 500, and a toner image of each color is formed on the image carrier 201. The intermediate transfer belt 301 of the intermediate transfer unit 300 is in contact with the image carrier 201, and the toner image formed on the image carrier 201 is superimposed on the intermediate transfer belt 301 by the primary transfer member 302 for each color. Is primarily transferred.

The multicolor toner image on the intermediate transfer belt 301 is
The secondary transfer is performed collectively by the secondary transfer roller 401 of the secondary transfer unit 400 on the recording medium fed from the feed unit 600. Here, the secondary transfer unit 400 is rotatable about a rotation center 402, and the intermediate transfer belt 301 is selectively provided only during the secondary transfer.
Pressurized. The recording medium on which the toner image has been transferred
After being conveyed to the fixing unit 800 by the heat transfer unit 700 and fixing the toner image by applying heat and pressure, the discharge conveyance unit
The sheet is discharged from the discharge unit 901 to the outside via the apparatus 900, and the image formation is completed.

FIGS. 8 and 9 show a secondary transfer section 400 and a transport section 700.
Is shown. A drive gear 403 is provided at an end of the secondary transfer roller 401, and drive is transmitted from the apparatus main body via a gear 405 provided at a rotation center 402 of the secondary transfer unit 400. The secondary transfer frame 406 is provided rotatably about a rotation center 402, and the secondary transfer frame 406 is provided by a cam (not shown) or the like.
By controlling the rotation of 406, the secondary transfer roller 401 is brought into contact with the intermediate transfer belt 301 as shown in FIG.
As shown in FIG. 9B, the secondary transfer roller 401 is
Separated from 01. The secondary transfer roller 401 is held on the secondary transfer frame 406 via a sliding bearing 408 and a pressure spring 407 at both ends thereof. When the secondary transfer roller 401 comes into contact with the intermediate transfer belt 301 as shown in FIG. Is biased with a predetermined pressure.

On the other hand, the transport section 700 is provided with a transport belt 701 and a transport roller 702 for transporting the recording medium. The transport belt 701 is composed of a transport roller 702 and a belt drive shaft 703.
The drive is transmitted from the apparatus main body by a drive gear 704 provided on the belt drive shaft 703.

[0006]

However, in the above-mentioned conventional configuration, the secondary transfer section 400 has its secondary transfer frame 406 provided.
And a mechanism for rotating the secondary transfer frame 406 is required. For this reason, the number of parts is large, the number of assembly steps is also large, and there has been a problem that the production cost is increased.

Further, since the drive means of the apparatus main body is provided outside the side plate of the apparatus main body, the secondary transfer section 400 located inside the side plate is provided.
In addition, transmitting the drive to the two locations of the transport unit 700 also causes a problem that the number of parts and the number of assembling steps are increased.

Accordingly, the present invention simplifies the mechanism by eliminating the need for a frame for moving the transfer means to and from the image carrier or the intermediate transfer means, and simplifies the device configuration by reducing the number of drive transmission points. It is intended to provide a forming apparatus.

[0009]

In order to solve the above problems, a typical configuration of an image forming apparatus according to the present invention is a first configuration.
, A first gear to which a driving force is transmitted from the first rotator, a second gear engaged with the first gear, and a driving force to be transmitted from the second gear. A second rotating body, wherein the second rotating body is capable of moving toward and away from the first rotating body around the second gear as a swing center. When the rotating body is separated from the first rotating body, a driving force is transmitted from the second gear.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. 1 is an overall configuration diagram of the image forming apparatus according to the present embodiment, FIG. 2 is a plan view illustrating a drive transmission mechanism to a transfer unit, and FIGS. 3 and 4 are diagrams illustrating an operation of a drive transmission mechanism of the transfer unit. It is.

In the image forming apparatus shown in FIG. 1, a latent image is formed by a latent image forming unit 10 on a photosensitive drum 21 as an image carrier as a first rotating body in a process cartridge 20. The latent image is developed by the developing units 31 to 34 of each color rotated by the developing unit switching mechanism 30, and a toner image of each color is formed on the photosensitive drum 21. The toner images of each color on the photosensitive drum 21 are primary-transferred by the primary transfer roller 24 onto an intermediate transfer belt 28 as an intermediate transfer unit in a superimposed manner, and a multicolor toner image is formed on the intermediate transfer belt 28.

The recording medium stored in the feed cassette 50 is separated and fed one by one by a pickup roller 51, and is synchronized with a multicolor toner image on the intermediate transfer belt 28 by a registration roller section 52 to a secondary transfer section. Is conveyed. At this time, the secondary transfer roller 40, which is a transfer means as a second rotating body of the secondary transfer unit, is switched from a state separated from the intermediate transfer belt 28 to a contact state, and the multicolor toner image is collectively formed on the recording medium. Then, secondary transfer is performed. Thereafter, the recording medium is conveyed to the fixing unit 70 via the conveying unit 60, and after the toner image is fixed by applying heat and pressure, the recording medium is discharged outside the apparatus from the discharge unit 80, and the image formation is completed. .

The process cartridge 20 includes a photosensitive drum 21
And an intermediate transfer belt 28, and is configured to be detachable from the apparatus main body. A charging roller 25 is provided on the outer periphery of the photosensitive drum 21.A cleaning unit 26 for collecting residual toner on the photosensitive drum 21 is disposed downstream of the charging roller 25 in the rotation direction. Section (primary transfer section). Intermediate transfer belt of primary transfer section
A primary transfer roller 24 is provided inside 28, and is urged to the photosensitive drum 21 via an intermediate transfer belt 28.

The intermediate transfer belt 28 is stretched by a tension roller 23 and a drive roller 22, and is rotated in a direction indicated by an arrow in FIG. Downstream of the secondary transfer portion of the intermediate transfer belt 28 (upstream of the primary transfer portion), a reverse transfer is performed to reversely transfer the secondary transfer residual toner on the intermediate transfer belt 28 to the photosensitive drum 21 and collect it by the cleaning portion 26. A charge applying unit 29 is provided, and is selectively brought into contact with the intermediate transfer belt 28 during cleaning. The process cartridge 20 is provided with a waste toner storage unit 27, and the waste toner collected by the cleaning unit 26 is transported and stored in the waste toner storage unit 27.

In the process cartridge 20, the photosensitive drum 21 and the driving roller 22 are positioned with respect to the apparatus main body.
Driving force is transmitted to each from the apparatus main body. Also, at least the primary transfer bias of the primary transfer roller 24, the charging roller
The charging bias of 25 and the reverse bias of the reverse charge applying means 29 are supplied from the apparatus main body.

The details of the drive transmission section of the secondary transfer roller 40 will be described with reference to FIG. Process cartridge 20
The drive roller 22 of the intermediate transfer belt 28 is provided with a gear 46 that rotates integrally with the drive roller 22. The gear 46 is a first gear that is a first gear that rotates about a shaft 45 provided on the apparatus main body. It is in mesh with the gear 44. The first idle gear 44 also meshes with a second idle gear 43, which is a second gear that rotates about a shaft 42 provided on the apparatus main body, and the second idle gear 43 is connected to the end of the secondary transfer roller 40. Transfer gear 41 fixed
Is engaged. That is, the drive of the secondary transfer roller 40 is transmitted from the drive roller 22 of the intermediate transfer belt 28 via the first idle gear 44 and the second idle gear 43.

As shown in FIG. 3, the shaft of the secondary transfer roller 40 is swingably supported by an elongated hole 47 that draws an arc around the second idle gear 43. Gear 46. Cams 22 a are rotatably attached to both ends of the driving roller 22, and are in contact with rollers 40 a provided at both ends of the secondary transfer roller 40. Accordingly, when the cam 22a is rotated, the roller 40a of the secondary transfer roller 40 is pushed in due to the phase thereof, and the secondary transfer roller 40 is separated from the intermediate transfer belt 28 as shown in FIG. 3, or as shown in FIG. Then, the secondary transfer roller 40 can be brought into a state of being urged by the intermediate transfer belt 28.

With this configuration, the drive is always transmitted to the secondary transfer roller 40 from the drive roller 22 of the intermediate transfer belt 28 via the first idle gear 44 and the second idle gear 43. . Therefore, the secondary transfer roller 40
The secondary transfer roller 40 can be directly separated from and brought into contact with the intermediate transfer belt 28 without cutting off the drive without providing a frame for holding and rotating the transfer roller. Further, the drive transmission to the secondary transfer roller 40 as the transfer unit can be shared with the intermediate transfer belt as the intermediate transfer unit, and the drive transmission mechanism can be simplified.

The secondary transfer roller 40 is connected to the intermediate transfer belt 28.
The mechanism for moving the transfer gear 41 away from the base gear may be any configuration as long as the transfer gear 41 rotates around the second idle gear 43.
For example, the shaft of the transfer gear 41 and the shaft of the second idle gear 43 may be connected by an arm. In addition, the effect of the present invention can be obtained by adopting a configuration in which the contact is made by a known mechanism, such as using a solenoid instead of using a cam.

[Second Embodiment] Next, a second embodiment of the image forming apparatus according to the present invention will be described. FIG. 5 is a plan view illustrating a drive transmission mechanism of the transfer unit and the transport unit according to the present embodiment, and FIG. 6 is a side view illustrating the drive transmission mechanism of the transfer unit and the transport unit. The same reference numerals are given to the same parts in the description, and the description will be omitted.

In the image forming apparatus according to the present embodiment, the second idle gear 43 is further provided with a transport unit as a transport unit.
The drive is also transmitted to 60. As shown in FIG.
In the transport section 60, a transport belt 61 is stretched by a roller shaft 62 and a transport belt drive shaft 63 at a central portion in the transport direction, and is rotatable in the transport direction. On both sides of the transport belt 61, an auxiliary transport belt 65 is provided with respective rollers 66 and a transport belt drive shaft 63.
And is stretched by.

A gear portion 64 is formed at one end of the transport belt drive shaft 63, and is connected to the second idle gear 43. That is, as shown in FIG. 6, the first idle gear 44 and the second idle gear
The drive transmitted via 43 is transmitted to both the first idle gear 44 of the secondary transfer roller 40 and the gear portion 64 of the transport belt 61.

Thus, in addition to the effects obtained by the configuration shown in the first embodiment, the drive can be transmitted to the transport unit 60 regardless of whether the secondary transfer roller 40 is separated from the intermediate transfer belt 28 or not. it can. The transport unit 60 as a transport means
Can be shared with the intermediate transfer belt as the intermediate transfer means, and the drive transmission mechanism can be further simplified.

In each of the above embodiments, an image forming apparatus using an intermediate transfer member as the first rotating member has been described as an example. However, an image bearing member (photosensitive drum) that carries a toner image of each color. The present invention can be similarly applied to an image forming apparatus of a type in which the image is transferred to a recording medium.

The drive mechanism according to the present invention is not limited to a transfer unit, but is applied to a drive mechanism for two rotating members that are driven and separated from each other, such as an image carrier, a developing unit, and a charging unit. It is possible.

[0026]

As described above, in the image forming apparatus according to the present invention, the first gear to which drive is transmitted from the image carrier or the intermediate transfer means, and the drive to be transmitted from the first gear to the transfer means. And the transfer unit is configured to rotate about the second gear and move away from and to the image carrier or the intermediate transfer unit, so that the transfer unit is always in the image carrier or Drive can be transmitted from the intermediate transfer unit.

Therefore, it is possible to directly contact and separate the transfer means from the image carrier or the intermediate transfer means without disconnecting the drive without providing a frame for holding and rotating the transfer means. As a result, the production cost can be reduced by simplifying the transfer / separation mechanism of the transfer means, and since there is no intermittent drive of the transfer means, the influence of the impact on the image is eliminated, and the image quality can be improved. Can be planned.
Further, the drive transmission to the transfer unit can be shared with the intermediate transfer unit, and the drive transmission mechanism can be simplified.

Further, since the drive is transmitted from the second gear to the transfer means provided adjacent to the transfer means, regardless of whether the transfer means is separated from the image carrier or the intermediate transfer means. The drive can be transmitted to the transporting means. Further, the drive transmission to the conveying means can be shared with the image carrier or the intermediate transfer means, and the drive transmission mechanism can be further simplified.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a plan view illustrating a drive transmission mechanism to a transfer unit.

FIG. 3 is a diagram illustrating an operation of a drive transmission mechanism of a transfer unit.

FIG. 4 is a diagram illustrating an operation of a drive transmission mechanism of a transfer unit.

FIG. 5 is a plan view illustrating a drive transmission mechanism of a transfer unit and a transport unit according to a second embodiment.

FIG. 6 is a side view illustrating a drive transmission mechanism of a transfer unit and a transport unit.

FIG. 7 is an overall configuration diagram of an image forming apparatus according to a conventional example.

FIG. 8 is a plan view illustrating a transfer unit and a transport unit according to a conventional example.

FIG. 9 is a side view illustrating a secondary transfer unit and a transport unit according to a conventional example.

[Explanation of symbols]

 10 latent image forming unit 20 process cartridge 21 photosensitive drum 22 drive roller 22a cam 23 tension roller 24 primary transfer roller 25 charging roller 26 cleaning unit 27 waste toner storage unit 28 intermediate transfer belt 29 ... reverse charge applying means 30 ... developing unit switching mechanism 31-34 ... developing unit 40 ... secondary transfer roller 40a ... roller 41 ... transfer gear 42 ... shaft 43 ... second gear 44 ... first gear 45 ... shaft 46 … Gear 47… Elongated hole 48… Biasing means 50… Feeding cassette 51… Pickup roller 52… Registration roller part 60… Transport part 61… Transport belt 62… Roller shaft 63… Transport belt drive shaft 64… Gear part 65… Auxiliary Conveyor belt 66 Roller 70 Fixing section 80 Discharge section

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H032 AA05 BA09 BA23 2H071 BA03 BA15 BA20 BA27 CA01 CA05 DA09 DA26 3J009 DA18 EA11 EA21 EA32 EA44 ED05 FA16 3J028 EA07 EA09 EB33 EB35 EB42 EB63 FC32 FC49 FC32 FC49

Claims (4)

[Claims] A first rotating body, a first gear to which a driving force is transmitted from the first rotating body, a second gear engaged with the first gear, and a second gear. A second rotating body to which a driving force is transmitted from a gear, wherein the second rotating body is movable toward and away from the first rotating body around the second gear as a swing center. And a driving force transmitted from the second gear when the second rotating body is separated from the first rotating body. 2. The apparatus according to claim 1, wherein the second rotator slides within a range in which engagement with the second gear is maintained, and is capable of coming into contact with and separating from the first rotator. The drive mechanism according to claim 1. 3. An image carrier or an intermediate transfer unit for carrying a toner image, and a transfer unit detachable from the image carrier or the intermediate transfer unit, wherein the toner image is transferred onto a recording medium by the transfer unit. In an image forming apparatus for forming an image by transferring, a first gear to which drive is transmitted from the image carrier or the intermediate transfer means, and a second gear to transmit drive from the first gear to the transfer means
The transfer means is rotated around the second gear and is separated from and contacts the image carrier or the intermediate transfer means, so that the drive is always transmitted from the second gear. An image forming apparatus, comprising: 4. A transfer device provided adjacent to the transfer device and configured to transfer a recording medium, wherein the transfer device receives a drive from the second gear. The image forming apparatus as described in the above.