JP4094822B2 - Fixing apparatus and image forming apparatus having the fixing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a fixing member and a pressure member that is in pressure contact with the fixing member, and passes the recording medium carrying the toner image between the fixing member and the pressure member, thereby allowing the toner image to be recorded on the recording medium. In particular, the present invention relates to a fixing device that fixes the toner image and an image forming apparatus having the fixing device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, it is well known to employ a fixing device of the above type in an image forming apparatus configured as a copying machine, a printer, a facsimile machine, or a multifunction machine having at least two of these functions. In this type of fixing device, since the fixing member and the pressure member are in pressure contact with each other, when the recording medium is jammed between them, the pressure contact force is released so that the jammed recording medium can be easily taken out. Need to be configured. However, in the conventional fixing device, the mechanism for releasing the pressure contact force between the fixing member and the pressure member is complicated, and the drawback of increasing the cost is inevitable. Note that releasing the pressure contact force between the fixing member and the pressure member means that the pressure contact force between the fixing member and the pressure member that are in contact with each other is weakened or separated from each other.
[0003]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION A first object of the present invention is to provide a fixing device that eliminates the above-mentioned conventional drawbacks and can release the pressure contact force between a fixing member and a pressure member with a simple configuration, and an image forming apparatus having such a fixing device. The second object is to provide the above.
[0004]
[Means for Solving the Problems]
In order to achieve the first object, the present invention provides a fixing device of the type described at the beginning, which is movably supported with respect to a housing of the fixing device and presses the pressure member against the fixing member. A pressure transmission member that transmits pressure to the pressure member; and a pressure release member that is movably supported by the pressure transmission member, and the pressure contact between the pressure member and the fixing member by the operation of the pressure release member. The pressure transmission member is configured to operate in a direction in which the force is released, and the pressure release member presses the casing of the fixing device by its swinging, and the pressure member and the fixing member are pressed by the reaction force. A fixing device is proposed in which the pressure transmission member is operated in a direction in which the pressure contact force is released.
[0005]
Similarly, in order to achieve the first object, the present invention, in the fixing device of the type described at the beginning, is supported movably with respect to the housing of the fixing device and presses the pressure member against the fixing member. A pressure transmission member that transmits the applied pressure to the pressure member; and a pressure release member that is movably supported by the pressure transmission member. By the operation of the pressure release member, the pressure member and the fixing member The fixing device is configured to operate the pressure transmission member in a direction in which the pressure contact force is released, and the pressure release member is formed integrally with a guide member for guiding a recording medium. Proposed (claim 2).
[0006]
The fixing device according to claim 1 or 2, wherein the pressure transmission member is swingably supported with respect to the casing, and the pressure release member is swingably supported by the pressure transmission member. (Claim 3).
[0007]
The fixing device according to any one of claims 1 to 3, wherein the pressure release member is swingably assembled to the pressure transmission member by being fitted to the pressure transmission member, and the fixing device includes: It is advantageous if the housing prevents the pressure transmission member from falling off (claim 4).
[0008]
Further, in the fixing device according to any one of claims 1 to 4, it is advantageous that the pressure release member is configured to operate in conjunction with an opening operation of a main body cover of the image forming apparatus main body. (Claim 5).
[0010]
Further, in the fixing device according to the second aspect, it is advantageous that the pressure release member is configured to operate together with the guide member in conjunction with the opening operation of the main body cover of the image forming apparatus main body. Item 6).
[0011]
In order to achieve the second object, the present invention proposes an image forming apparatus comprising the fixing device according to any one of claims 1 to 6 (claim 7).
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0013]
FIG. 1 is a schematic sectional view showing an example of an image forming apparatus. In the image forming apparatus shown here, the photoconductor 2 arranged in the main body 1 rotates counterclockwise, and at this time, the surface of the photoconductor is uniformly charged by the charging device 3. The charged surface is irradiated with laser light L emitted from the laser optical system 4, thereby forming an electrostatic latent image on the photosensitive member. The electrostatic latent image is visualized as a toner image when passing through the developing device 5.
[0014]
On the other hand, a recording medium P made of, for example, transfer paper is accommodated in a paper feed cassette 6 disposed below the photoreceptor 2, and the uppermost recording medium P is connected to the transfer device 8 by rotation of the paper feed roller 7. The toner image is fed between the photosensitive member 2 and the toner image on the photosensitive member is transferred to the recording medium P. Untransferred toner adhering to the photoconductor after the toner image is transferred is removed by the cleaning device 9.
[0015]
The recording medium P to which the toner image has been transferred is further conveyed upward and passes through the fixing device 10, and at this time, the toner image is fixed to the recording medium. The recording medium P that has exited the fixing device 10 is guided by the guide member 12 and another guide member, and is discharged onto the paper discharge tray 11 by the paper discharge roller pair 13.
[0016]
As shown in FIG. 2 in an enlarged manner, the fixing device 10 includes a fixing roller 15 that is an example of a fixing member and a pressure roller 16 that is an example of a pressure member. These rollers 15 and 16 are the fixing device. 10 are supported so as to be rotatable, and each of them rotates in a direction indicated by an arrow in FIG. A heater 18 is provided inside the fixing roller 15, and the fixing roller 15 is heated to a temperature suitable for fixing the toner image by the heater. As described above, the recording medium P carrying the toner image T transferred from the photosensitive member is sent between the fixing roller 15 and the pressure roller 16 as indicated by an arrow A in a direction in which the toner image is in contact with the fixing roller 15. When the recording medium P passes through the recording medium P, the toner is heated and pressurized, and the toner image is fixed on the recording medium.
[0017]
As described above, the fixing device includes the fixing member and the pressure member that is in pressure contact with the fixing member, and passes the recording medium carrying the toner image between the fixing member and the pressure member to pass the toner. The image is fixed on the recording medium.
[0018]
FIG. 3 is an external perspective view showing only the outline of the fixing device 10, and a pair of pressure transmission members 20 are inserted through insertion openings 19 formed in respective end regions in the longitudinal direction of the casing 17 of the fixing device 10. (See FIG. 4) As shown in FIG. 2, the engaging portion 21 at the lower end of each pressure transmission member 20 is rotatably engaged with a pin 22 fixed to the housing 17. FIG. 2 shows only the pressure transmission member 20 and the pin 22 on one side, but the other side has the same configuration. A bearing 23 is fitted to each shaft end portion 16 </ b> A of the pressure roller 16, and each pressure transmission member 20 is in pressure contact with each bearing 23. One end of a tension spring 24 which is an example of an urging member is locked to each pressure transmission member 20, and the other end of the spring 24 is locked to the housing 17. As a result, each pressure transmission member 20 is urged to rotate counterclockwise in FIG. 2, thereby pressing the pressure roller 16 against the fixing roller 15 via each bearing 23.
[0019]
As described above, each pressure transmission member 20 is movably supported with respect to the casing 17 of the fixing device 10, and serves to transmit the pressing force that presses the pressure member against the fixing member to the pressure member. . In the illustrated example, each pressure transmission member 20 is supported to be swingable with respect to the housing 17. With this configuration, the pressure roller 16 is in pressure contact with the fixing roller 15, and the toner on the recording medium passing through these rollers 15 and 16 can be pressed.
[0020]
On the other hand, as shown in FIG. 3, each pressure transmission member 20 is provided with an attachment hole 25, and a pin 27 of the pressure release member 26 is rotatably fitted in each attachment hole 25. As shown in FIGS. 2 and 4, each pressure release member 26 is located in a space defined by a standing wall portion 17 </ b> A, a horizontal wall portion 17 </ b> B, and a side wall portion 17 </ b> C on its side. In this way, each pressure release member 26 is movably supported by each pressure transmission member 20, and in the illustrated example, the pressure release member 26 is swingably supported by each pressure transmission member 20. Yes.
[0021]
In a normal state in which the fixing roller 15 and the pressure roller 16 are in pressure contact with each other, each pressure release member 26 occupies the position shown in FIG. 2, and at this time, each pressure release member 26 does not restrain each pressure transmission member 20. Therefore, each pressure transmission member 20 presses the pressure roller 16 against the fixing roller 15 by the action of the tension spring 24 as described above.
[0022]
Here, when the recording medium is jammed between the fixing roller 15 and the pressure roller 16 and the operation of the image forming apparatus is stopped and the rotation of the rollers 15 and 16 is stopped, the jammed recording medium (hereinafter referred to as the jammed recording medium). Need to be removed). Accordingly, first, as shown in FIG. 1, an operator such as a user or a serviceman holds the main body cover 1A of the image forming apparatus main body supported by the image forming apparatus main body 1 via a pin 28 so as to be capable of rotating and opening. The main body cover 1A is opened by rotating in the direction of the arrow, and the fixing device 10 is exposed to the outside. Next, the operator rotates each pressure release member 26 in the direction indicated by the arrow B in FIG. Then, the cam part 29 formed in each pressure release member 26 presses against the standing wall part 17A of the housing 17, and each pressure releasing member 26 receives a reaction force from the standing wall part 17A. As a result, as shown in FIG. 5, each pressure transmission member 20 rotates around the pin 22 in a direction away from the fixing roller 15, and the pressure contact force between the pressure roller 16 and the fixing roller 15 is released. That is, the pressure contact force between the fixing roller 15 and the pressure roller 16 is weakened, or these rollers are separated from each other. When both rollers 15 and 16 are separated from each other, the bearing 23 is also moved away from the fixing roller 15 together with the pressure roller 16. In this way, the pressure transmission member is operated in the direction in which the pressure contact force between the pressure roller 16 and the fixing roller 15 is released by the operation of each pressure release member 26, in this example, swinging.
[0023]
In this example, the guide member 12 is rotatably supported by the housing 17 via a pin 30, and the fixing roller 15 is rotated by rotating the guide member 12 in the direction indicated by the arrow in FIG. And an upper opening (not shown in FIG. 3) between the pressure roller 16 and the pressure roller 16 is opened. As a result, the operator can easily remove the jammed paper. By reverse operation, the pressure roller 16 can be brought into pressure contact with the fixing roller 15 again.
[0024]
As described above, the pressure release member 26 presses the casing 17 of the fixing device 10 by swinging, and the reaction force causes the pressure contact force between the pressure roller 16 and the fixing roller 15 to be released. Since the transmission member 20 is configured to operate, the pressure transmission member 20 can be reliably operated to release the pressure contact force between the fixing roller 15 and the pressure roller 16.
[0025]
The strength of the pressure transmission member 20 that applies a large pressure to the pressure roller 16 is required. For this reason, it is preferable to comprise the pressure transmission member 20 with a metal. On the other hand, the pressure release member 26 is a portion that is touched by an operator, and the pressure release member 26 is preferably made of resin in order to suppress heating.
[0026]
In FIG. 5, the hatching indicating the cross section is omitted, and this is the same in FIGS.
[0027]
FIG. 6 is an explanatory diagram showing the positional relationship between the pressure release member 26 assembled to the pressure transmission member and the housing 17. As described above, each pressure release member 26 is swingably assembled to each pressure transmission member 20 by being fitted to each pressure transmission member 20. The release member 26 is positioned in a state where the pressure transmission member 20 and the side wall portion 17 </ b> C of the housing 17 are sandwiched. Therefore, as shown in FIG. 3, the pressure release member 26 is simply fitted into the mounting hole 25 of the pressure transmission member 20, and the side wall portion 17C does not provide any special drop-off prevention means. The release member 26 can be prevented from falling off the pressure transmission member 20. The casing 17 of the fixing device 10 can prevent the pressure release member 26 from dropping from the pressure transmission member 20. Since the pressure transmission member 20 is always subjected to pressure by the tension spring 24, as can be seen from FIG. Thus, since it is not necessary to provide a special means for preventing the pressure release member 26 from dropping from the pressure transmission member 20, the cost of the fixing device 10 can be effectively reduced.
[0028]
Further, as shown in FIGS. 7 and 8, when a claw 31 is formed on the main body cover 1A and the main body cover 1A is opened, the pressure release member 26 is rotated in the direction of arrow B by the claw 31 to add to the fixing roller 15. It can also be configured to release the pressure contact force of the pressure roller 16. In this way, if the pressure release member 26 is configured to operate in conjunction with the opening operation of the main body cover 1A, the operator can more easily handle jammed paper. Furthermore, when the main body cover 1A is closed, the pressure release member 26 is pressurized by the pressurizing portion 32 provided on the main body cover 1A, and the pressure release member 26 is rotated in the direction opposite to the arrow B. The fixing roller 15 and the pressure roller 16 can be brought into pressure contact with each other automatically. Thereby, operation can be further simplified.
[0029]
Further, as shown in FIGS. 9 and 10, if the guide member 12 and the pressure release member 26 are integrally formed instead of supporting the guide member 12 to the housing 17, the pressure release member 26 is moved in the direction of arrow B. By rotating, the guide member 12 is also rotated together, and the upper part of the fixing roller 15 and the pressure roller 16 can be opened. As described above, when the pressure release member 26 is formed integrally with the guide member 12 for guiding the recording medium, the pressure release operation and the guide member release operation can be performed by a single operation, which improves operability. it can.
[0030]
Further, as shown in FIGS. 11 and 12, the pressure release member 26 and the guide member 12 are integrally formed, and when the main body cover 1A is opened, the pressure release member 26 is rotated by the claw 31. The pressure release operation and the guide member 12 opening operation can be performed simply by opening the main body cover 1A, and the operability during the jam paper processing can be further enhanced. As described above, by configuring the pressure release member 26 to operate together with the guide member 12 in conjunction with the opening operation of the main body cover 1A, the operability can be significantly improved. Other configurations in FIGS. 7 to 12 are the same as those in FIGS.
[0031]
【The invention's effect】
According to each of the inventions according to claims 1 to 7, the press contact between the fixing member and the pressure member can be released with a simple configuration.
[0032]
In particular, according to the fourth aspect of the present invention, the pressure release member can be prevented from falling off from the pressure transmission member simply by fitting the pressure release member to the pressure transmission member, thereby simplifying the structure of the fixing device and reducing the cost. Can be achieved.
[0033]
According to the inventions according to claims 2, 5 and 6, the operation at the time of releasing the press contact between the fixing member and the pressure member can be particularly simplified.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an image forming apparatus.
FIG. 2 is a cross-sectional view of a fixing device and its peripheral portion.
FIG. 3 is a schematic external perspective view of the fixing device, showing a state when a pressure transmission member is attached to a housing.
FIG. 4 is a perspective view showing a state in which a pressure transmission member and a pressure release member are assembled to a housing.
FIG. 5 is a cross-sectional view showing a state when the pressure contact between the fixing roller and the pressure roller is released.
FIG. 6 is a diagram illustrating an assembled state of the pressure transmission member and the pressure release member with respect to the housing.
FIG. 7 is a cross-sectional view illustrating another example of the image forming apparatus.
8 is a cross-sectional view showing a state when the main body cover shown in FIG. 7 is opened.
FIG. 9 is a cross-sectional view illustrating still another example of the image forming apparatus.
10 is a cross-sectional view showing a state when a guide member and a pressure release member shown in FIG. 9 are rotated. FIG.
FIG. 11 is a cross-sectional view illustrating still another example of the image forming apparatus.
12 is a cross-sectional view showing a state when the main body cover shown in FIG. 11 is opened.
[Explanation of symbols]
1A Main body cover 10 Fixing device 12 Guide member 17 Housing 20 Pressure transmission member 26 Pressure release member P Recording medium T Toner image

Claims (7)

Fixing having a fixing member and a pressure member pressed against the fixing member, and fixing the toner image to the recording medium by passing a recording medium carrying the toner image between the fixing member and the pressure member In the apparatus, a pressure transmission member that is movably supported with respect to the casing of the fixing device and transmits a pressure force that presses the pressure member against the fixing member to the pressure member, and is movable to the pressure transmission member A pressure release member that is supported, and is configured to operate the pressure transmission member in a direction in which the pressure contact force between the pressure member and the fixing member is released by the operation of the pressure release member. The pressure release member is configured to press the housing of the fixing device by swinging the pressure release member and to actuate the pressure transmission member in a direction in which the pressure contact force between the pressure member and the fixing member is released by the reaction force. A fixing device characterized by the above. Fixing having a fixing member and a pressure member pressed against the fixing member, and fixing the toner image to the recording medium by passing a recording medium carrying the toner image between the fixing member and the pressure member In the apparatus, a pressure transmission member that is movably supported with respect to the casing of the fixing device and transmits a pressing force that presses the pressure member against the fixing member to the pressure member, and is movable to the pressure transmission member A pressure release member that is supported, and is configured to operate the pressure transmission member in a direction in which the pressure contact force between the pressure member and the fixing member is released by the operation of the pressure release member. The fixing device, wherein the pressure release member is formed integrally with a guide member for guiding the recording medium. The fixing device according to claim 1, wherein the pressure transmission member is swingably supported with respect to the housing, and the pressure release member is swingably supported by the pressure transmission member. The pressure release member is swingably assembled to the pressure transmission member by fitting to the pressure transmission member, and is prevented from falling off from the pressure transmission member by a housing of the fixing device. The fixing device according to claim 3. The fixing device according to claim 1, wherein the pressure release member operates in conjunction with an opening operation of a main body cover of the main body of the image forming apparatus. The fixing device according to claim 2, wherein the pressure release member operates together with a guide member in conjunction with an opening operation of a main body cover of the image forming apparatus main body.   An image forming apparatus comprising the fixing device according to claim 1.

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