JPH05107971A - Fixing device of image forming device - Google Patents

Abstract

PURPOSE:To facilitate positioning operation of a member such as a guide plate, etc., against a press roll and assembly work of the device in the fixing device of a heating roll system provided with two fixing rolls faced to each other. CONSTITUTION:The pressurized state of the two rolls are set against the device which is constituted by having the heating roll 2 integrated with a heating source 3 attached to a main body by having a pressing roll 5 supported by the pressing frame 20 and rocking the pressing frame 20 through a supporting shaft 22. The guide plate can be positioned against the fixing roll 5 by having a front part unit 25 and a back part unit 30 placed through the supporting shafts 22 and 31 in the pressing frame 20, the guide plates 26 and 33 are provided integrally to these units, and by having arm members 27 and 34 pressed to a bearing member 23. Furthermore, the press roll can be positioned against the heating roll in a state where the front and back units are attached to the pressing frame when the device is assembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating roller type fixing device used in an image forming apparatus for making a copy using an electrophotographic system such as an electronic copying machine or a printer, and more particularly to a roller device. The present invention relates to an apparatus provided with a mechanism capable of accurately positioning a guide plate or the like for guiding a sheet to the nip portion of the pressure roller with respect to the pressure roller.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electronic copying machine or a laser printer for making a copy by using an electrophotographic method, a toner image is formed on an image bearing member such as a photosensitive drum, and the toner image is formed. There is used a means for making a copy by applying heat or pressure to the paper on which the toner has been transferred through a fixing device to melt the toner and press it against the paper. As the fixing device, a heating roller type fixing device is generally used, and in the heating roller type fixing device, a heating roller having a built-in heating source and a pressure roller are arranged so as to face each other. A means for pressing the roller against the heating roller is used to set the nip pressure between both rollers. As the heating roller type fixing device, for example, a device shown in Japanese Utility Model Laid-Open No. 2-81540 is used, and in the fixing device of the conventional example, the nip pressure between both rollers can be easily adjusted. It is provided so that it can be set to.

Further, a general heating roller type fixing device has a structure as shown in FIG. 3, for example, and does not have a heating roller 2 having a heating source 3 such as a halogen lamp built therein. The fixing device 1 is configured by disposing the pressure roller 5 so as to face it. Then, the toner image bearing surface of the paper is made to correspond to the heating roller 2, guided to the fixing device, and the toner is melted by applying heat and pressure, and the melted toner is pressed and fixed on the paper. Is used. An oil application device 10 and a temperature detection means 11 such as a thermistor are arranged for the heating roller 2. In the oil application device 10, a member such as a foam roller or a felt is used to apply silicone oil to the surface of the heating roller. To prevent the melted toner from adhering to the surface of the roller.
The temperature detecting means detects the surface temperature of the roller and controls the heating temperature of the toner by the heating roller so as to be maintained within a certain range.

With respect to the fixing device 1, the peeling claws 15 and 16 are arranged at the paper discharge portion, the paper is peeled from the roller surface, and the heating action is performed while the paper remains attached to the roller surface. A mechanism is provided to prevent this. The peeling claw member is provided with a mechanism such as lightly pressing the tip of the claw against the roller surface, and the claw member is arranged for each of the two fixing rollers. In the heating roller type fixing device, a guide plate 13 is arranged at the entrance portion in order to guide the paper to the nip position of the roller, and the guide plate 13 guides the paper so that the leading end portion of the paper is the roller. It is possible to accurately guide to the nip position.

In the heating roller type fixing device as shown in the conventional example, the frame supporting the pressure roller 5 is provided so as to be swingable with respect to the main body frame 12 supporting the heating roller 2. The positioning of both rollers and the nip pressure can be easily set. Further, with respect to the main body frame 12, peeling claw members 15 and 16,
Means for separately supporting the guide plates 13 and 14 are provided. In the case of configuring the fixing device, the positions where the guide plates are attached to the front and rear portions of the pressure roller are set to portions that can guide the paper in a good condition.

[0006]

However, as described above, when the means for fixing the guide plate and the like individually to the main body frame and setting the guide position of the sheet is used, the fixing device thereof is used. It takes a lot of time and effort to assemble, and an assembly error becomes a big problem. Further, in order to individually position a large number of members constituting the fixing device with respect to the main body frame, it is necessary to strictly control the manufacturing accuracy of each member, which increases the manufacturing cost of parts and the like. I have a problem. further,
Even if the manufacturing precision of each member is controlled, the device may not operate properly if the assembly is not controlled accurately.

In the fixing device, particularly, in the front guide plate for guiding the sheet toward the nip position of the roller device, the leading end of the sheet is guided to a position slightly above the nip portion. Is being done. However, if the leading end of the guide plate is not accurately positioned, there are problems such as paper wrinkles on the fixed paper, image distortion, and peeling defects. Therefore, as described above, if paper wrinkles or image distortions occur,
A defective copy may be created, and if peeling failure occurs, the operation of the fixing device is stopped, and it becomes necessary to perform maintenance.

Further, even when the rear guide plate arranged at the nip portion of the roller is not properly positioned, even if the paper accommodating device is separated by the separation claw, the function of guiding the paper thereafter is obtained. However, there is a problem in that the jamming of the paper occurs in the paper conveyance path without performing the above. Further, in the guide plate on the discharge side, if the position with respect to other members such as the peeling claw is not accurately set, the guide of the paper discharged from the nip portion of the roller may be hindered. It may cause a jam in. In addition to the above-mentioned problems, it is troublesome to attach the rear guide plate after attaching the peeling claw member in the narrow portion of the frame of the fixing device, and the work of accurately positioning the guide plate is also troublesome. There is also a problem that there is a problem, and it also requires a lot of maintenance work to remove many of these members separately during maintenance.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional fixing device, in which a pressure roller, front and rear guide plates, peeling claw members, etc. are mounted on a single pressure frame and fixed. It is an object of the present invention to provide a device that can be easily assembled to the device and can be easily positioned for each member.

[0010]

According to the present invention, a heating roller having a heating source and a pressure roller are disposed so as to face each other, and a means for pressing the pressure roller against the heating roller is used. The present invention relates to a fixing device that sets a predetermined nip pressure between both rollers. In the fixing device of the present invention, the pressure roller is supported via a pressure frame, and the pressure frame is swingably provided with respect to the main body frame supporting the heating roller, and the pressure frame is interposed therebetween. A nip state of both rollers is set, and front and rear guide plates and a peeling claw member are swingably provided on the pressure frame via support shafts. Further, in the apparatus of the present invention, the positioning member is arranged so as to project from each of the guide plates, and the positioning member is engaged with the bearing member of the pressure roller, thereby positioning the guide plate. Can be configured to do.

As described above, by attaching the front and rear guide plates and the peeling claw member to the pressure frame supporting the pressure roller, the pressure frame is made into one unit and the main frame of the fixing device is formed. Can be incorporated into
The work of assembling the fixing device can be easily performed.
Then, the pressing state of the pressure roller with respect to the heating roller can be set via the pressure frame, and at the same time, other members can be automatically positioned. Further, since the guide plate can be accurately positioned with respect to the bearing member of the pressure roller, the problem of the guide position with respect to the paper does not occur, and the problem of wrinkles or the like on the paper or image misalignment occurs. It is also possible to prevent such problems. Further, also during maintenance of the apparatus, since the pressing frame is rocked to release the pressing state of both rollers and other members can be removed, maintenance work can be easily performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fixing device for an image forming apparatus of the present invention will be described with reference to the illustrated example. The fixing device 1 of the present invention shown in FIG. 1 includes a heating roller 2 having a heating source 3 such as a halogen lamp and a pressure roller having no heating source, as in the case of the conventional heating roller type fixing device. 5 and 5 are arranged to face each other. In the two fixing rollers, the heating roller 2 may be a core member made of metal such as aluminum whose surface is covered with an elastic body such as thin silicone rubber and whose surface is coated with fluororesin. It is possible to use, as the pressure roller 5, a metal core member whose surface is covered with a relatively thick elastic body.

Then, the heating roller 2 is attached to a main body frame of a fixing device (not shown), and the pressure roller 5 is supported by the pressure frame 20 and is attached to the main body frame to combine both rollers. I am trying.
In the embodiment of the present invention, the oil applying device, the temperature detecting means, and other mechanisms arranged around the heating roller 2 are omitted, but those members are the same as those of the conventional fixing device. It is the one that can be used.

In the fixing device of the present invention configured as described above, the pressure frame 20 for supporting the pressure roller 5 is provided.
Is supported by the main body frame via a support shaft 22, and is swingably provided via the support shaft 22. A shaft support 21 is provided at the center of the pressure frame 20.
On the other hand, a bearing member 23 such as a bearing for supporting the shaft 8 of the pressure roller 5 is attached. Therefore, the pressure roller 5 is positioned on the pressure frame via the bearing member 23, and is pressed by the heating roller 2 to rotate following the roller 2. In addition,
The shaft supporting the pressure frame 20 may be attached via another shaft member, but in the present invention, the pressure frame is supported via the support shaft 22 for ease of explanation. , And a mechanism for swingably supporting the front unit 25 provided with the front guide plate 26 by using the shaft.

On the upstream side of the pressing frame 20 in the sheet moving direction, a front unit 2 is provided via a support shaft 22.
5 is arranged, and the front unit is swingably provided via a support shaft 22. The front unit 25 is integrally provided with a front guide plate 26 and an arm member 27. When the fixing device is assembled, the tip of the arm member 27 is positioned with respect to the bearing member 23. You can do it. Then, by using the positioning means as described above, the front end portion of the front guide plate 26 is made to correspond to the nip position of the two fixing rollers, and the front end portion of the sheet guided by the guide plate 26 is moved relative to the heating roller. And a little above the nip position. After that, with the leading end of the sheet in contact with the heating roller, it is possible to follow the rotation of the heating roller 5 and guide the sheet toward the nip position.

On the downstream side of the pressure frame 20, a rear unit 30 is swingably provided via a support shaft 31. The rear unit 30 integrally includes a rear guide plate 33 and a positioning arm member 34 via a support bracket 32. In addition, the support bracket 32
Is provided with a support member 32a for the peeling claw member 35, and the peeling claw member 35 is swingably supported by the support member 32a. Then, as shown in FIG. 1, the rear guide plate 33 can be positioned by positioning the rear unit 30 with the tip of the arm member 34 pressed against the bearing member 23. At the same time, the peeling claw member can be positioned with respect to the pressure roller. Any known mechanism can be used for the supporting means for the peeling claw member 35, the means for urging the tip of the claw toward the pressure roller, and the like.

In the fixing device 1 of the present invention configured as described above, the heating roller 2 is incorporated in the main body frame, and then the pressure frame 20 is attached via the support shaft 22. .. Then, by pressing the pressure roller 5 supported by the pressure frame 20 toward the heating roller, a nip pressure having a predetermined value can be set between both rollers. In addition, in order to adjust the nip pressure between the rollers, the pressure frame 20
Can be swung via the support shaft 22, and any conventionally known means can be used as the swing mechanism of the pressurizing frame. Further, in the pressure frame 20,
Attach the front and rear guide plates 26, 33 to the pressure roller 5 in advance.
Since it can be made to correspond to the heating roller 2 in a state of being positioned with respect to, the work of assembling the device can be easily performed.

When performing maintenance work on the fixing device 1 of the present invention, the pressure frame 20 is oscillated counterclockwise through the support shaft 22 so that the nip state between both rollers is maintained. To cancel. After that, as shown in FIG. 2, the front unit 25 and the rear unit 30 are swung via the respective support shafts 22 and 31, and the front and rear guide plates are separated from the pressure roller 5. Then, in the state shown in FIG. 2, the members supported by the pressurizing frame are separated from each other so that maintenance work can be performed on the respective members. In addition, when performing maintenance on the heating roller 2 and its surroundings, after the pressure frame 20 is swung, a wide space is formed in the lower portion of the main body frame, so a member supported by the main body frame using this space. Can be removed.

The fixing device 1 of the present invention configured as described above can be applied to any image forming apparatus such as an electronic copying machine or a laser printer, and pressurizes by following a heating roller. It can be used in devices where rollers are rotated. In the heating roller type fixing device, even when a heat source is used for the pressure roller, a mechanism for supporting the pressure roller on the pressure frame can be used. Further, in the present invention, in addition to using the means for supporting the peeling claw member with respect to the rear unit, the peeling claw member can be positioned with respect to the pressure roller by using other supporting means. ..

[0020]

Since the fixing device of the image forming apparatus of the present invention has the above-mentioned structure, it is provided with the front and rear guide plates and the peeling claw member with respect to the pressure frame supporting the pressure roller. By mounting the pressure frame
One unit can be incorporated in the main body frame of the fixing device, and the work of assembling the fixing device can be easily performed. Then, the pressing state of the pressure roller with respect to the heating roller can be set via the pressure frame, and at the same time, other members can be automatically positioned. Also,
Since the guide plate can be accurately positioned with respect to the bearing member of the pressure roller, the problem of the guide position with respect to the paper does not occur, and wrinkles or the like occur on the paper.
It is also possible to prevent problems such as image misalignment. Further, during maintenance of the apparatus, the pressure frame can be swung to release the pressed state of both rollers, and at the same time, other members can be removed, so that maintenance work can be performed easily.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a fixing device of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a pressure frame.

FIG. 3 is an explanatory diagram of a conventional fixing device.

[Explanation of symbols]

1 fixing device, 2 heating roller, 5 pressure roller, 20 pressure frame, 21 shaft support, 2
2 support shafts, 23 bearing members, 25 front unit, 26 front guide plates, 27 arm members,
30 rear unit, 31 support shaft, 32 bracket, 33 rear guide plate, 34 arm member,
35 Peeling claw member.

Claims (1)

[Claims] 1. A heating roller having a heating source and a pressure roller are arranged so as to face each other, and a predetermined nip pressure is applied between both rollers by using a means for pressing the pressure roller against the heating roller. In a fixing device to be set, the pressure roller is supported via a pressure frame, the pressure frame is swingably provided with respect to a main body frame supporting the heating roller, and both rollers are interposed via the pressure frame. The nip state is set, and the front and rear guide plates and the peeling claw member are swingably provided to the pressure frame via the support shafts, and the positioning members are projected on the respective guide plates. The fixing device of the image forming apparatus is arranged so that the positioning member can be positioned with respect to each guide plate by engaging the positioning member with the bearing member of the pressure roller. Place