JP2001201975A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of lightening the burden imposed on a user by reducing the number of operations at the time of jamming disposal. SOLUTION: This device is provided with a pressing release lever 25 capable of moving between a holding position where the press-contact state of a pair of fixing rollers 21 and 22 is held and a releasing position where the press- contact state is released, and the lever 25 actuated from the holding position to the releasing position at the time of jamming disposal of sheet material is restored from the releasing position to the holding position interlocked with operation for closing a door 7 opened for the purpose of the jamming disposal.

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 in which, when a fed sheet material is conveyed from below to above, the sheet material passes through a fixing unit having a transfer portion of an image carrier and a pair of rollers. About.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile, a fixing device including a roller pair including a fixing roller and a pressure roller is widely used. In this type of image forming apparatus, when a transfer material carrying an unfixed toner image is nipped and conveyed between a fixing roller and a pressure roller, the unfixed toner image is fixed to the transfer material by the action of heat and pressure. At the time of the fixing, the sheet material may be jammed while being held between the roller pairs.

[0003] When performing such a jam clearance, a user opens an opening / closing member consisting of a cover or a door, and then turns a knob to rotate one of a pair of rollers to release the nipping state of the sheet or operate a release lever. The pressed state of the roller pair is released to perform the jam sheet processing.

[0004]

However, in the conventional image forming apparatus, when a jam occurs, an operation of opening the door, operating the lever, removing the jammed paper, returning the lever, and closing the door. It is necessary, and the number of operations is large, which is a burden on the user. It is to be noted that, even in a conventional apparatus, an image forming apparatus main body is of an alligator type, and when the alligator is opened, the pressure of the roller pair of the fixing device is released. When closing, it requires great power. Further, in the case of a copying machine or facsimile in which a sorter is provided at the upper part of the apparatus or an image is output at the lower part of the scanner, it is very difficult to implement an alligator type configuration.

[0005] The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide an image forming apparatus capable of reducing the number of operations during jam processing and reducing the burden on a user.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a fixing device having a transfer section of an image carrier and a roller pair when a fed sheet material is conveyed from below to above. And a release means having a lever movable between a position for holding the pressure-contact state of the roller pair and a position for releasing the pressure-contact state. The lever, which is sometimes operated from the holding position to the releasing position, returns from the releasing position to the holding position in conjunction with the operation of closing the opening / closing member opened for jam clearance.

The present invention is effective when an elastic means is provided for urging the lever in the direction of moving from the holding position to the release position in conjunction with the opening operation of the opening / closing member.

Further, the present invention is effective when a connecting member for connecting the opening / closing member and the lever and moving the lever from the holding position to the releasing position by opening the opening / closing member is effective. .

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic layout diagram showing an embodiment of an image forming apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a photosensitive member serving as an image carrier which is rotated in a counterclockwise direction, and reference numeral 2 denotes a charging device for performing a charging process on the surface of the photosensitive member. The charged photoreceptor is exposed to laser light based on image information by the optical writing means 3 to form an electrostatic latent image on its surface. This electrostatic latent image is visualized by the developing device 4. A sheet feeding device 10 is disposed below the photoreceptor 1, and when the sheet feeding roller 11 rotates, the top sheet is moved to the registration roller 1.
Conveyed to 2. The registration roller 12 stops the fed sheet at 1 o'clock, and then conveys the sheet to a transfer position in synchronization with the visible image formed on the photoconductor 1. And
At the transfer position, a toner image, which is a visible image, is transferred to a sheet under the operation of the transfer device 5, and the sheet on which the toner image has been transferred is conveyed to the fixing device 20. The photoreceptor 1 after the transfer is cleaned by the cleaning device 6.

The fixing device 20 is, as shown in FIG.
A roller pair including a fixing roller 21 and a pressure roller 22 is provided. In this case, the pressure roller 22 has a pressure spring 24 locked at the other end of a pressure lever 23 having one end pivotally supported.
It is pressed against 1.

In the image forming apparatus configured as described above, the sheet fed from the sheet feeding device 10 is conveyed upward from substantially below in a substantially vertical direction, passes through the fixing device 20 via the transfer position, and is discharged. The sheet is ejected from the paper unit to the outside of the apparatus, but the sheet may jam in the conveyance path. Then, there is a possibility that the jam occurs in a state where the jam is sandwiched between the nip between the fixing roller 21 and the pressure roller 22.

Generally, it is premised that jams are processed by the user, and therefore, ingenuity has been devised so that the processing can be easily performed. In this embodiment, the fixing device 20 is provided with a pressure release lever 25 as pressure release means for releasing the contact pressure of the pressure roller 22 against the fixing roller 21. One end of the pressure release lever 25 is pivotally supported by the pin 26, and the other end of the pressure release lever 25 is formed with a gripper 27 operated by a user. It can be moved to and from the position where the pressed state is released. The pressure release lever 25 is integrally provided with a cam 28 for operating the pressure lever 23. In the holding position shown in FIG. 2, the cam 28 slightly contacts the side edge of the pressure lever 23, but slightly. Are spaced apart.

Further, the image forming apparatus main body is provided with a right door 7 as an opening / closing member which is closed at the time of image formation. The right door 7 is centered on the fulcrum 9 by a closed position indicated by a solid line in FIG. It is opened and closed between the indicated open positions. The right door 7 has a cover surface on the outside, and includes the transfer device 5, a sheet conveyance guide (not shown), and a guide guide 8 described later on the inside. When the right door 7 is closed, the gripping portion 27 of the pressure release lever 25 located at the holding position slightly abuts on the guide 8 of the right door 7 or is slightly separated.

Here, the fixing roller 21 and the pressure roller 22
When a jam occurs while being held between the nips of the image forming apparatus, the user can remove the right door 7 of the main body of the image forming apparatus to clear the jam.
Is released, the grip portion 27 appears. Then, when the user holds down the holding portion 27 of the released pressure release lever 25 and lowers it, the pressure release lever 25 moves from the holding position shown in FIG. 2 to the release position shown in FIG. And held in this position. By the movement of the pressure release lever 25, the pressure between the rollers is released by rotating the pressure lever 23 counterclockwise via the cam 28 against the action of the pressure spring 24. At this time, the pressure release lever 25 is held at the release position by the tensile force of the pressure spring 24, and the user can easily remove the jam between the fixing roller 21 and the pressure roller 22 from which the pressure has been released. it can.

After the jam has been cleared, even if the user forgets to return the pressure release lever 25 from the release position to the original holding position, the right door 7 is closed to automatically move the pressure release lever 25 from the release position. It can be returned to the holding position. That is, as shown in FIG. 4, a guide 8 is provided on the inner surface side of the right door 7, and when the right door 7 is closed, the guide 8 comes into contact with the grip portion 27 of the pressure release lever 25, and Push toward. When the right door 7 is completely closed,
The pressure release lever 25 is also returned to the holding position along the guide 8.

In the image forming apparatus configured as described above, the pressure release lever 25 returns to the holding position by the closing operation of the door 7, thereby simplifying the user's trouble of jam clearance.
FIG. 5 is an explanatory diagram showing another embodiment of the present invention,
It has a pressure release lever 25 configured similarly to the above embodiment. The other end of a compression spring 30 as an elastic means having one end fixed to the fixing device 20 is connected to the pressure release lever 25. The compression spring 30 constantly urges the right door 7 with an elastic force in a direction to open the door.

In the image forming apparatus configured as described above, a jam occurs in a state where the jam occurs between the nip between the fixing roller 21 and the pressure roller 22, and when the right door 7 is opened to deal with the jam, the compression spring is opened. The pressure release lever 25 pressed by 30 is moved from the holding position to the release position. Therefore, the user only needs to open the right door 7 and press the pressure release lever 2
5 is pushed by the compression spring 30 and moves to the release position.
The jammed paper can be processed immediately, and after the processing, if the right door 7 is closed, the pressure release lever 25 returns to the original holding position as in the above embodiment. Therefore, the jam processing can be performed more easily. It is not necessary to operate the pressure release lever 25 at such a speed that the pressure release lever 25 pops out when the right door 7 is opened. Therefore, the strength of the compression spring 30 is such that the pressure release lever 25 moves smoothly when the right door 7 is opened. Is set to

FIG. 6 is an explanatory view showing still another embodiment of the present invention, and has a pressure release lever 25 configured similarly to the above embodiment. The other end of the wire 31 as a connecting member, one end of which is fixed near the fulcrum 9 of the right door 7, is attached to the pressure release lever 25. The other end of a tension spring 32 as an elastic member whose one end is locked to the fixing device 20 is locked to the pressure release lever 25, and the elastic force in the direction of holding the pressure release lever 25 in the holding position is retained. Is always energized.

In the image forming apparatus constructed as described above, a jam occurs in a state where the jam occurs between the nip between the fixing roller 21 and the pressure roller 22, and when the right door 7 is opened to deal with the jam, the pressure is released. The lever 25 is moved from the holding position to the release position via the wire 31. Therefore, the user simply opens the right door 7 and the pressure release lever 25 moves to the release position, so that the jammed paper can be processed immediately. When the right door 7 is closed after the jam has been cleared, the tension spring 3 is closed.
By the action of 2, the pressure release lever 25 returns to the original holding position. Therefore, the user can smoothly and easily perform the jam processing without operating the pressure release lever 25. In order to perform the above operation, the positions of the wire 31 to be fixed to the pressure release lever 25 and the right door 7 are selected, and the strength of the tension spring 32 is determined.

In the above embodiment, the wire 3
Metal, plastic, rubber, and the like can be considered as the material of the first, and a leaf spring or a torsion spring can be used as the compression spring 30 or the extension spring 32.

[0022]

According to the first aspect of the present invention, the lever which has been moved to the release position when a jam has occurred between the nip of the fixing roller and the pressure roller is automatically returned to the holding position by closing the opening / closing member. Since the jam can be easily removed, the opening / closing member is closed even if the lever is not returned, and the next image forming operation can be performed.

According to the configuration of claim 2, in addition to the effect of claim 1, the lever is automatically moved from the holding position to the release position by opening the opening / closing member. It will be much better.

According to the third aspect of the present invention, similarly to the second aspect, the lever is automatically moved to the release position by opening the opening / closing member, so that the operability of the jam clearance is significantly improved. Get better.

[Brief description of the drawings]

FIG. 1 is a schematic layout diagram of an image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram illustrating a state in which a pressure release lever of a fixing device according to an exemplary embodiment of the present invention is in a holding position.

FIG. 3 is an explanatory diagram showing a state in which a pressure release lever of the fixing device is in a release position.

FIG. 4 is an explanatory diagram showing the relationship between the movement of a door and the operation of a pressure release lever.

FIG. 5 is an explanatory diagram showing another embodiment of the present invention.

FIG. 6 is an explanatory view showing still another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 photoconductor drum 5 transfer device 7 right lever 20 fixing device 21 fixing roller 22 pressure roller 25 pressure release lever 30 compression spring 31 wire

Claims (3)

[Claims] 1. An image forming apparatus according to claim 1, wherein when the fed sheet material is conveyed from below to above, the sheet material passes through a transfer unit of the image carrier and a fixing device having a pair of rollers. And a release unit having a lever movable between a position for holding the pressed state and a position for releasing the pressed state, wherein the lever operated from the holding position to the release position during the jam processing of the sheet material is used for removing the jam. An image forming apparatus that returns to a holding position from a release position in conjunction with an operation of closing an opening / closing member opened for processing. 2. The image forming apparatus according to claim 1, further comprising: an elastic unit that urges the lever in a direction from the holding position to the release position in conjunction with an opening operation of the opening / closing member. An image forming apparatus comprising: 3. The image forming apparatus according to claim 1, further comprising a connecting member that connects the opening and closing member and the lever, and moves the lever from the holding position to the release position by opening the opening and closing member. An image forming apparatus, comprising: