JP2000075718A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a fixing device by facilitating the operation of mounting the fixing device in an image forming device, and previously preventing the user from failing to perform operations on the fixing device or making operational errors. SOLUTION: A fixing device 17, which can be freely removably attached to an image forming device main body, has a pressure release member 34 capable of being switched to a second position where a fixing roller 30 and a pressurizing roller 32 are pressurized into contact with each other by the pressurizing force of a pressurizing member 36 or a first position where the fixing roller 30 and the pressurizing roller 32 are released out of contact with each other against the pressurizing force of the pressurizing member 36, and a positioning member 35 engaged in and disengaged from a positioning hole 39 in the image forming device main body. In this case, the positioning member 35 is disengaged from the positioning hole 39 in the image forming device main body as the pressure release member 34 is switched to the first position, and is engaged in the positioning hole 39 in the image forming device main body as the pressure release member 34 is switched to the second position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which is detachable from a main body of an image forming apparatus such as a printer and fixes a toner image on a recording material.

[0002]

2. Description of the Related Art Conventionally, for example, in a color image forming apparatus, a fixing device for pressing and heating and fixing four color toner images transferred to a sheet material is more burdensome than a fixing device for fixing a single color toner image. And the life is shortened. Therefore, there is a demand for a fixing device that is detachable from the image forming apparatus main body. Therefore, it is important to facilitate the operation of attaching and detaching the fixing device.

Here, a conventional fixing device will be schematically described with reference to FIGS. 4 and 5. FIG. 4 (a) and 5 (a) are schematic sectional views of a conventional fixing device, and FIGS. 4 (b) and 5 (b) are views of a positioning member of the conventional fixing device as viewed from the direction of arrow H. .

In FIG. 1, a fixing roller 60 is formed by forming a silicone rubber around a hollow aluminum core bar and forming a release layer on the surface thereof. A halogen heater 61 is disposed inside the fixing roller. The pressure roller 62 is formed by forming a silicone rubber on a hollow aluminum core and forming a release layer on the surface thereof.A halogen heater 63 is disposed inside the pressure roller 62, and the pressure roller 62 is pressed against the fixing roller 60 by a pressing member 66. Form a nip.

The pressure releasing member 64 is rotatably disposed, and opens at a first position (releases the pressure contact) between the fixing roller 60 and the pressure roller 62 against the pressing force of the pressing member 66 (FIG. 4 ( a) and a second position (see FIG. 5A) where the pressing roller 62 is pressed against the fixing roller 60.

In the first position, it is possible to prevent permanent deformation of the rubber portion caused by continuing the press-contact between the fixing roller 60 and the pressure roller 62 for a long period of time after manufacture until use. Further, when an accident such as a jam that stagnates without being pinched and conveyed into the fixing device occurs, the sheet P pinched by the nip can be removed.

On the other hand, at the second position, the positioning member 65 is further rotated in the direction of arrow G and positioned in the positioning hole 69, so that normal use is possible.

The user can arbitrarily switch the fixing device between the first position and the second position during normal use or when an accident such as a jam occurs as described above. The operation is not monitored or detected by the image forming apparatus at all, and it is necessary to confirm the pressurized state and the mounted state of the fixing device before the image forming apparatus starts operating.

[0009]

However, in the fixing device having the above structure, if the positioning member 65 is fitted in the positioning hole 69, the pressure contact between the fixing roller 60 and the pressure roller 62 is released. However, since the image forming apparatus is in a usable state (print ready state), an undesired image or an unfixed image is printed or the fixing apparatus is damaged. there were.

When an accident such as a jam occurs,
An operation of releasing the pressure contact between the fixing roller 60 and the pressure roller 62 (a switching operation of the pressure releasing member 64) to remove the sheet material P sandwiched between the fixing roller 60 and the pressure roller 62;
Since the operation of attaching and detaching the fixing device from the image forming apparatus (the operation of switching the positioning member 65) must be performed separately, there is a problem that it is difficult to understand, and the usability and operability (usability) are poor.

It is an object of the present invention to facilitate the operation of mounting the fixing device on the image forming apparatus, to prevent a user from neglecting or erroneously operating the fixing device, and to prevent damage to the fixing device. Is to prevent it.

[0012]

A typical configuration of the present invention for achieving the above object is a fixing device which is detachable from an image forming apparatus main body and fixes a toner image on a recording material. It is possible to switch to a second position where the fixing roller and the pressing roller are pressed against each other by the pressing force of the pressing member or a first position where the pressing between the fixing roller and the pressing roller is released against the pressing force of the pressing member. A pressure release member, and a positioning member that engages with a positioning hole on the image forming apparatus main body side or is released from engagement with the positioning hole on the image forming apparatus main body side, wherein the positioning member replaces the pressure release member. The engagement with the positioning hole on the image forming apparatus main body side is released in conjunction with switching to the first position.

Further, in the above configuration, the positioning member is engaged with a positioning hole on the image forming apparatus main body side in conjunction with switching the pressure release member to the second position.

Further, in the above configuration, the fixing device is brought into a predetermined position by releasing the engagement between the connector electrically connected to the connector on the image forming apparatus main body side and the positioning hole on the image forming apparatus main body side. A mounting release member for pushing out of the operating position to release the connection of the connector.

In a fixing device which is detachable from the main body of the image forming apparatus and fixes a toner image on a recording material, a second position or a second position where the fixing roller and the pressure roller are pressed against each other by the pressing force of the pressing member. A pressure releasing member that can be switched to a first position for releasing the pressure contact between the fixing roller and the pressure roller against the pressing force of the pressing member, and a connector that is electrically connected to the connector on the image forming apparatus main body side. The connection of the connector is released in conjunction with switching the pressure release member to the first position.

Further, in the above configuration, the connector is connected in conjunction with switching the pressure releasing member to the second position.

According to the above arrangement, when the fixing roller and the pressing roller are not pressed against each other, the fixing device is pushed out of the predetermined operation position, and the image forming apparatus main body is electrically connected to the fixing device. Since the connector to be used has been released,
Operation becomes impossible. Therefore, it is possible to prevent problems such as damage to the fixing device due to a user's forgetting to operate or an erroneous operation. Further, when the fixing roller and the pressure roller are pressed against each other, the fixing device is always mounted at a predetermined operation position with respect to the image forming apparatus main body, and the image forming apparatus main body and the fixing device are electrically connected. Is also connected, so that it is in an operable state. Therefore, a clear image can always be obtained.

Further, the positioning member is made to protrude from the fixing device when the positioning member is engaged with the positioning hole on the image forming apparatus main body side,
By storing the fixing member in the fixing device when disengaging from the positioning hole of the image forming apparatus main body, the protrusion of the positioning member is stored in the fixing device when the fixing device is attached or detached. There is no obstacle during the attaching / detaching operation, and the workability (usability) can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a fixing device and an image forming apparatus according to the present invention will be specifically described with reference to FIGS. 1 is a schematic diagram of a fixing device according to the present invention (when pressure is released), FIG. 2 is a schematic diagram of a fixing device according to the present invention (when pressure is applied), and FIG. 3 is a color image provided with the fixing device according to the present invention. It is a schematic diagram of a forming device.

First, a schematic configuration of the color image forming apparatus according to the present invention will be described with reference to FIG. In the color image forming apparatus shown in FIG. 3, a plurality of toner images sequentially formed on the photosensitive drum 1 are sequentially transferred (primary transfer) to an intermediate transfer drum (medium-resistance elastic roller) 20 as an intermediate transfer body. The toner images are superimposed, and then the plurality of toner images are collectively transferred from the intermediate transfer drum 20 to the sheet material P as a recording material using the transfer belt 12 as a secondary contact transfer means (secondary transfer). ) Is configured.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) which is repeatedly used as a first image carrier, and is driven to rotate at a predetermined peripheral speed in the direction of arrow R1. . The photoreceptor drum 1 is uniformly charged to a predetermined polarity and potential by a primary charging roller 2A in the course of rotation, and is then subjected to image exposure 3 by an image exposing unit to thereby obtain a first color component image of a target color image. Is formed.

Next, the electrostatic latent image is developed by the first developing unit 4Y with the yellow toner Y as the first color.
Each of the developing units 4Y, 4M, 4C, and 4Bk (yellow, magenta, cyan, and black) is mounted on a rotary 4a that rotates in the direction of an arrow (clockwise) in the figure, and is used for development by rotation of the rotary 4a. The developing device is disposed at a developing position D facing the surface of the photosensitive drum 1.

An intermediate transfer drum 20 is arranged in contact with the photosensitive drum 1, and is driven to rotate at the same speed as the photosensitive drum 1 in the direction of arrow R20.

The yellow toner image of the first color formed and carried on the photosensitive drum 1 passes through a primary transfer nip portion T1 between the photosensitive drum 1 and the intermediate transfer drum 20, and the intermediate transfer drum The primary transfer is performed on the surface of the intermediate transfer drum 20 by an electric field and a pressure generated by a primary transfer bias applied to a primary transfer bias power supply (not shown). Hereinafter, this process is called primary transfer.

Hereinafter, similarly, a magenta toner image of the second color,
The cyan toner image of the third color and the black toner image of the fourth color are sequentially superimposed and transferred on the intermediate transfer drum 20, and a composite color toner image corresponding to the target color image is formed on the intermediate transfer drum 20.
Formed on the surface.

A transfer belt 12 is provided below the intermediate transfer drum 20.
Are arranged. The transfer belt 12 is an intermediate transfer drum 20
And is in contact with the intermediate transfer drum 20 from below. The transfer belt 12 is supported by a transfer roller 10 and a transfer belt driving roller 11, and a secondary transfer bias is applied to the transfer roller 10 by a secondary transfer bias source (not shown).

The transfer unit 5 supports the transfer roller 10 and the transfer belt drive roller 11 by bearings on the transfer frame 9. The transfer unit 5 bears the transfer belt drive roller 11 against the intermediate transfer drum 20 with respect to the image forming apparatus main body. It is supported so as to be able to contact / separate freely (not shown). The transfer frame 9 further holds a pressing spring 14 and a pressing top 15 which are elastic pressing members for bringing the transfer roller 10 into contact with the intermediate transfer drum 20 at a predetermined secondary transfer pressure. The transfer unit 5 can be brought into contact with or separated from the intermediate transfer drum 20 at a predetermined timing by an electromagnetic clutch (not shown) and a pressure cam 16 provided in the main body of the image forming apparatus.

The secondary transfer of the composite color toner image superimposedly transferred (primarily transferred) onto the intermediate transfer drum 20 onto the sheet material P is performed while the transfer belt 12 is in contact with the intermediate transfer drum 20 and the cassette 21 or Each feeding means 2 from multi tray 22
The sheet material P fed one by one by the transfer rollers 3 and 24 is transferred to the secondary transfer nip T2 between the intermediate transfer drum 20 and the transfer belt 12 via the pre-transfer guide 8 by the registration rollers 7a and 7b. At the same time, a secondary transfer bias is applied to the transfer roller 10 from a secondary transfer bias power supply (not shown). The composite transfer toner image is collectively and secondarily transferred from the intermediate transfer drum 20 to the sheet material P by the secondary transfer bias. Hereinafter, this process is referred to as secondary transfer.

The sheet material P on which the secondary transfer has been completed is separated from the intermediate transfer drum 20 by the transfer belt 12 having a large capacitance, and is attracted and conveyed by the transfer belt 12. The sheet material P sucked and conveyed to the transfer belt 12 is
The resultant composite color toner image is heated and fixed by the fixing device 17 and then discharged by the discharge means 25 to the discharge section 26 in the upper part of the apparatus.

Next, the fixing device 17 according to the present invention will be described in detail with reference to FIGS. As shown in FIGS. 1 and 2, the fixing roller 30 is formed by forming a silicone rubber around a hollow aluminum core and forming a release layer on the surface thereof. I have. The pressure roller 32 forms silicon rubber on a hollow aluminum core,
A release layer is formed on the surface, a halogen heater 33 is disposed inside, and a pressing member 36 is pressed against the fixing roller 30 to form a nip.

The pressure releasing member 34 is rotatably disposed, and opens (nips) the nip between the fixing roller 30 and the pressure roller 32 against the pressing force of the pressing member 36 (see FIG. 1). )
Then, it can be switched to a second position (see FIG. 2) where the pressing roller 32 is pressed against the fixing roller 30.

The positioning member 35 is released from the engagement between the projection 38 and the positioning hole 39 on the image forming apparatus main body side by the pressing force of the positioning return member 37 in conjunction with the switching operation of the pressure releasing member 34. The first position stored inside the fixing device 17 and the fixing device 17 against the pressing force of the positioning return member 37
It can be switched to the second position where it projects further and fits into the positioning hole 39 on the image forming apparatus main body side.

At the first position, it is possible to prevent permanent deformation of the rubber portion caused by continuing the press-contact between the fixing roller 30 and the pressure roller 32 for a long period of time from the time of manufacture to the time of use. And a sheet material P inside the fixing device 17.
Can be removed when an accident such as a jam that stagnates without being properly conveyed occurs. On the other hand, in the second position, normal use is possible.

The sheet material P to which the unfixed image is transferred is conveyed to a nip (pressing portion) formed by the fixing roller 30 and the pressure roller 32 along the entrance guide 42, and the sheet material P Heat and pressure are applied by the pressure roller 32, and the above-described transferred image is fixed.

Next, the operation of the pressure releasing member 34 and the positioning member 35 will be described with reference to FIGS. The user may fix the fixing roller 30 and the pressure roller 32 of the fixing device 17 for some reason.
The fixing device shown in FIG. 3 is used when the nip is released (pressure release) or when the pressure release operation is performed to suppress permanent deformation in the rubber portions of the fixing roller 30 and the pressure roller 32 due to long-time pressure contact. The door 50 is opened in the direction of arrow E, and the pressure release member 34 is pushed up in the direction of arrow A as shown in FIG.
At this time, the positioning member 35 is pushed up by the positioning return member 37 in conjunction with the switching operation of the pressure release member 34, and the protrusion 38 of the positioning member 35 is moved from the positioning hole 39 on the image forming apparatus main body side into the fixing device 17 inside. Is stored in Then, the fixing device 17 is moved in the direction of arrow F shown in FIG. 1 by a mounting release member 43 provided on the image forming apparatus main body side, and a connector for electrically connecting the image forming apparatus main body and the fixing device 17 is provided. The connection between 40 and 41 is released, and the image forming apparatus becomes inoperable.

At the same time, a control circuit (not shown) in the image forming apparatus issues a message to the effect that the fixing device 17 has a problem, thereby notifying the user.

That is, when the fixing roller 30 and the pressing roller 32 are not pressed against each other, the fixing device 17 is pushed out from a predetermined operation position (the state shown in FIG. 2), and the image forming apparatus main body and the fixing device are Since the connectors 40 and 41 that electrically connect the device 17 with the connector 17 are also released, the device becomes inoperable.
As a result, the user is urged to perform an erroneous operation, and unintended printing due to an erroneous operation by the user can be prevented.
It is possible to prevent troubles such as damage to the fixing device due to a user's forgetting operation or erroneous operation.

The positioning member 35 is stored in the fixing device 17 when the fitting with the positioning hole 39 on the image forming apparatus main body side is released. The workability (usability) can be remarkably improved without the part 38 becoming an obstacle.

On the other hand, when the pressure releasing member 34 is in a state of being pushed down in the direction of arrow B as shown in FIG. 2, the projection 38 of the positioning member 35 interlocking with the switching operation of the pressure releasing member 34 is used for image formation. The fixing device 17 and the image forming device main body are electrically connected by the connectors 40 and 41 so that the fixing device 17 and the image forming device main body can be normally operated. It has become. That is, a print ready state is set.

That is, when the fixing roller 30 and the pressure roller 32 are pressed against each other, the fixing device 17 is always mounted at a predetermined operation position (the state shown in FIG. 2) with respect to the image forming apparatus main body. Since the connectors 40 and 41 for electrically connecting the image forming apparatus main body and the fixing device 17 are also connected, they are in an operable state. Thereby, a clear image can always be obtained.

In the above-described embodiment, a printer is exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, other image forming apparatuses such as a copying machine and a facsimile apparatus may be used. The same effect can be obtained by applying the present invention to a fixing device used in the image forming apparatus.

In the above-described embodiment, the electrophotographic method is exemplified as the recording method. However, the recording method is not limited to this, and another recording method such as an ink jet method may be used.

[0043]

As described above, according to the present invention,
In a state in which the pressure contact between the fixing roller and the pressure roller is neglected, the fixing device is pushed out of a predetermined operation position, and the connector for electrically connecting the image forming apparatus main body and the fixing device is also released. Operation becomes impossible. Therefore, it is possible to prevent problems such as damage to the fixing device due to a user's forgetting to operate or an erroneous operation. Furthermore,
When the fixing roller and the pressure roller are pressed against each other, the fixing device is always mounted at a predetermined operation position with respect to the image forming apparatus main body, and a connector for electrically connecting the image forming apparatus main body and the fixing apparatus. Are also connected, so that they can operate. Therefore, a clear image can always be obtained.

Further, the positioning member is made to protrude from the fixing device at the time of engagement with the positioning hole on the image forming apparatus main body side,
By storing the fixing member in the fixing device when disengaging from the positioning hole of the image forming apparatus main body, the protrusion of the positioning member is stored in the fixing device when the fixing device is attached or detached. There is no obstacle at the time of attaching / detaching operation, and workability (usability) can be remarkably improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a fixing device (when pressure is released) according to the present invention.

FIG. 2 is a schematic diagram of a fixing device (when pressurized) according to the present invention.

FIG. 3 is a schematic diagram of a color image forming apparatus provided with a fixing device according to the present invention.

FIG. 4 is a schematic diagram of a conventional fixing device (when pressure is released).

FIG. 5 is a schematic diagram of a conventional fixing device (when pressurized).

[Explanation of symbols]

 D: Development position P: Sheet material T1: Primary transfer nip T2: Secondary transfer nip Y, M, C, Bk: Toner 1: Photoconductor drum 2A: Primary charging roller 3: Image exposure 4Y, 4M, 4C, 4Bk developing device 4a rotary 5 transfer unit 7a, 7b registration roller 8 pre-transfer guide 9 transfer frame 10 transfer roller 11 transfer belt drive roller 12 transfer belt 14 pressure spring 15 pressure frame 16… Pressure cam 17… Fixing device 20… Intermediate transfer drum 21… Cassette 22… Multi trays 23, 24… Supply means 25… Discharge means 26… Discharge unit 30… Fixing roller 31… Halogen heater 32… Pressure roller 33 ... Halogen heater 34 ... Pressure release member 35 ... Positioning member 36 ... Pressing member 37 ... Positioning return member 38 ... Protrusion 39 ... Positioning holes 40 and 41 ... Connector 42 ... Inlet guide 43 ... Member 50: Fixing device door

Claims (7)

[Claims] 1. A fixing device which is detachable from a main body of an image forming apparatus and fixes a toner image on a recording material. Alternatively, a pressure releasing member that can be switched to a first position for releasing the pressure contact between the fixing roller and the pressure roller against the pressing force of the pressing member, and engaging with a positioning hole on the image forming apparatus main body side or image formation. A positioning member which is disengaged from the positioning hole on the apparatus main body side, wherein the positioning member is linked with switching the pressure release member to the first position, and the positioning hole on the image forming apparatus main body side Wherein the engagement with the fixing device is released. 2. The fixing device according to claim 1, wherein the positioning member is engaged with a positioning hole in an image forming apparatus main body in conjunction with switching the pressure releasing member to a second position. . 3. The fixing device according to claim 1, wherein the positioning member projects from the fixing device when the positioning member is engaged with the positioning hole on the image forming apparatus main body, and is stored in the fixing device when the engagement with the positioning hole on the image forming apparatus main body is released. The fixing device according to claim 1, wherein: 4. The fixing device according to claim 1, wherein the connector electrically connected to the connector on the image forming apparatus main body side, and the engagement between the positioning member and the positioning hole on the image forming apparatus main body side are released. And a mounting release member that releases the connection of the connector by pushing out from a predetermined operation position. 5. A fixing device which is detachably attached to an image forming apparatus main body and fixes a toner image on a recording material, wherein a second position at which a fixing roller and a pressure roller are pressed against each other by a pressing force of a pressing member. Or a pressure release member switchable to a first position for releasing the pressure contact between the fixing roller and the pressure roller against the pressing force of the pressing member; and a connector electrically connected to the connector on the image forming apparatus main body side. A fixing device, wherein the connection of the connector is released in conjunction with switching the pressure releasing member to the first position. 6. The fixing device according to claim 5, wherein a connector is connected in conjunction with switching the pressure release member to the second position. 7. An image forming apparatus, comprising: the fixing device according to claim 1;