JPH0635362A - Fixing device - Google Patents

Abstract

PURPOSE:To obtain a fixing device capable of surely releasing driving by preventing sliding abrasion. CONSTITUTION:As to the fixing device for an image forming device having a gear to be driven which can be engaged with a driving gear provided on the main body side of the image forming device, a sliding shaft on which the gear to be driven is attached on one end., which can slide in a shaft direction, and which is supported by a bearing, and an operation knob provided on the other end of the sliding shaft, and where engagement between the gear to be driven and the driving gear can be released by sliding the sliding shaft in the shaft direction by the operation knob; the bearing supporting the sliding shaft 23 is a rolling bearing 28, respective grooves in the shaft direction are provided on the inner ring surface of the rolling bearing 28 and on a surface which is brought into contact with the inner ring surface and which is corresponding to the sliding shaft, so that the sliding shaft 23 and the rolling bearing 28 are constituted to be mutually engaged so as to slide in the shaft direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an image forming apparatus such as a laser printer, a copying machine and a facsimile.

[0002]

2. Description of the Related Art FIG. 1 shows a schematic configuration of a conventionally known laser printer.

A sheet 50 fed from the sheet feeding cassette 11 partially protruding to the printer body 10 to the pickup roller by the bottom plate raising lever and fed in the direction of arrow a.
Is conveyed to the latent image carrier composed of the drum-shaped photoconductor 13 at a timing by the registration roller pair 12. The photoconductor drum 13 is rotationally driven clockwise by the rotation of the photoconductor drive shaft in the figure, and at this time, the surface thereof is charged by the charger 14. Then, a laser beam from the laser optical system 15 is irradiated to form an electrostatic latent image on the photoconductor. This latent image is visualized by the toner as it passes through the developing device 16, and this visible image is transferred onto the sheet 50 conveyed to the photosensitive drum 13 under the action of the transfer charger 17. The transferred visible image on the sheet is fixed by the fixing device 18. Then, the fixing device 18
The sheet 50 that has exited is discharged to the sheet discharge unit 19 in the arrow B direction, for example. On the other hand, after the visible image is transferred, the residual toner is removed from the photoconductor 13 by the cleaning device 20, and the photoconductor 13 is subjected to the neutralization action by the neutralization lamp and is prepared for the next printing.

The driven transmission mechanism of the fixing device 18 in such a laser printer has a simple structure so that the fixing roller can be manually rotated in an arbitrary direction when a jam occurs, for example, Japanese Patent Laid-Open No. 58-18663. The configuration is disclosed in the publication. This is because, as shown in FIG. 2, an idle gear 24 provided on a sliding shaft 23 meshes with a gear 22 arranged at the end of the fixing roller 21.
The gear 24 further meshes with the main body drive gear 25.

An operating knob 26 is provided at the other end of the sliding shaft 23. By moving the operating knob 26 in the axial direction, the fixing drive can be separated from the main body drive section.

The sliding shaft 23 is normally urged by the spring 27 to a position where the drive is transmitted, and when the drive is disconnected, the operation knob is resisted against the urging force of the spring 27. 26 is pulled and manually rotated.

In this case, the bearing provided to support the sliding shaft supports the operation in both the radial direction and the thrust direction, but when low durability is sufficient,
When a sliding bearing is used and high durability is required, a rolling bearing is used.

[0008]

However, when high durability and high loadability are required, the rolling bearing and the sliding shaft slide in the thrust direction, as shown in FIG. , Which has a clearance, and is normally rotated by the outer ring 28a and the inner ring 28b of the rolling bearing 28,
In addition to that, the sliding shaft 23 causes rotation with respect to the inner ring 28b, and since the material generally used for the rolling bearing has high hardness, as shown in FIG. 4B on the sliding shaft 23 side. A step due to wear gradually occurs.

When such a step occurs, the operation knob 2
When 6 is moved in the thrust direction, it creates a catch,
It becomes difficult to disconnect the drive, and the jam processing and the like cannot be performed smoothly.

Japanese Unexamined Patent Publication (Kokai) No. 58-59063 also discloses a structure in which one of the driving gear trains of the fixing system is released to disconnect the engagement of the fixing roller side with the driving gear. Have a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the prior art, and it is an object of the present invention to provide a fixing device capable of reliably performing drive release.

[0012]

The present invention solves this problem by
A driven gear that can be engaged with a drive gear provided on the main body side of the image forming apparatus, a sliding shaft that is mounted at one end and is slidable in the axial direction and supported by a bearing, and the sliding An image having an operation knob provided at the other end of the shaft, by which the sliding shaft can be slid in the axial direction to release the engagement between the driven gear and the drive gear. In the fixing device for the forming apparatus, the bearing that supports the sliding shaft is a rolling bearing, and the inner ring surface of the rolling bearing and the sliding shaft corresponding surface that is in contact with the surface are each provided with an axial groove, The solution is constituted by being configured to axially slidably engage one another.

In the same fixing device, the bearing that supports the sliding shaft is a rolling bearing, and in the area of the sliding shaft that is in contact with the rolling bearing, the side opposite to the sliding direction when released by the operating knob is used. Even if the taper is formed so that the gap between the sliding shaft and the rolling bearing becomes larger as the distance goes to, the above problem can be solved.

In the same fixing device, the bearing that supports the sliding shaft is a rolling bearing, and the surface of the rolling bearing facing the sliding shaft is provided with a member made of a material that is more easily worn than the sliding shaft. Even if it is arranged so as to have a clearance against the sliding shaft, the above problem can be solved.

Further, in the same fixing device, the bearing that supports the sliding shaft is a rolling bearing, and a space between the rolling bearing and the sliding shaft is a shrink fit, and a frame between the main body of the device and the rolling bearing is provided. Even if a member made of a material that is more easily worn than the frame or the rolling bearing is arranged so as to form a clearance with respect to the frame or the rolling bearing, the above problem can be solved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments based on the drawings.

FIG. 5 shows one configuration of the present invention. In the figure, flat knurled grooves are provided uniformly in the axial direction in the rolling bearing contact region of the sliding shaft 23. Corresponding grooves are provided on the inner circumferential surface of the inner ring of the rolling bearing 28 at a pitch that fits into the grooves provided on the shaft 23 so that the conventional clearance is not caused. As a result, the grooves are separated from each other as shown in FIG.
As shown in (1), there is no wear even when meshed and the shaft rotates. Sliding in the thrust direction is possible due to the gaps that are slightly present in the grooves.

FIG. 7 shows an invention having another structure. In the figure, the sliding shaft 23 is tapered. This taper slides from the middle of the area of the sliding shaft 23 in contact with the rolling bearing 28 to the sliding shaft 23 and the rolling bearing in the direction in which the sliding shaft 23 is slid when released by the operating knob, that is, in the direction opposite to the arrow direction. The gap with 28 becomes large. As a result, the support by the rolling bearing 28 is first ensured in the region with a small gap with the sliding shaft 23, and the rotational wear of the sliding shaft 23 with respect to the rolling bearing 28 occurs in the region with the small gap, and the broken line portion in the drawing shows. Even if a step is generated as described above, when the sliding shaft is slid by the operation knob, the step does not hinder the sliding operation.

FIG. 8 shows an invention having another structure. On the surface of the inner ring of the rolling bearing 28 facing the sliding shaft 23, the sliding shaft 23
The member 29 made of a material that is more easily worn than the sliding shaft 23
It is arranged so that it is still a skimmer. The presence of such a member causes wear on the member side,
There is no step on the sliding shaft.

FIG. 9 and FIG. 10 show the invention of still another configuration.

In FIG. 9, a member 30 made of a material that is more easily worn than the rolling bearing 28 is arranged between the rolling bearing 28 and the fixing frame 32 so that the rolling bearing 28 has a clearance. On the other hand, between the rolling bearing 28 and the sliding shaft 23, there is a shrink fit so that sliding wear does not occur. With such a configuration, even if abrasion occurs between the rolling bearing 28 and the sliding member 30 due to the whirling, the sliding member 30 side is worn, and therefore no step is generated. Sliding in the thrust direction by the operating knob
Since the rolling bearing 28 is generated between the rolling bearing 28 and the sliding member 30, the rolling bearing 28 is not affected by the sliding.
As a matter of course, the width needs to be wide enough to prevent the fitting of the sliding member 30 from the sliding member 30.

FIG. 8 shows an invention having another structure. On the surface of the inner ring of the rolling bearing 28 facing the sliding shaft 23, the sliding shaft 23
The member 29 made of a material that is more easily worn than the sliding shaft 23
It is arranged so that it is still a skimmer. The presence of such a member causes wear on the member side,
There is no step on the sliding shaft.

FIG. 9 and FIG. 10 show the invention of still another configuration.

In FIG. 9, a member 30 made of a material that is more easily worn than the rolling bearing 28 is arranged between the rolling bearing 28 and the fixing frame 32 so that the rolling bearing 28 has a clearance. On the other hand, between the rolling bearing 28 and the sliding shaft 23, there is a shrink fit so that sliding wear does not occur. With such a configuration, even if abrasion occurs between the rolling bearing 28 and the sliding member 30 due to the whirling, the sliding member 30 side is worn, so that no step is formed. Sliding in the thrust direction by the operating knob
Since the rolling bearing 28 is generated between the rolling bearing 28 and the sliding member 30, the rolling bearing 28 is not affected by the sliding.
As a matter of course, the width needs to be wide enough to prevent the fitting of the sliding member 30 from the sliding member 30.

In FIG. 10, a member 31 made of a material that is more easily worn than the main body frame 32 is arranged between the rolling bearing 28 and the fixing frame 32 so that the fixing frame 32 has a clearance. Between the rolling bearing 28 and the sliding shaft 23, similar to FIG. 9 and the example, there is a shivering to prevent sliding wear. With such a configuration, the sliding member 31 and the fixing frame 3 can be rotated around each other.
Even if abrasion occurs between the two, the sliding member 31 side is abraded, so that there is no step. It is the same as in the example of FIG. 9 that the rolling bearing 28 needs to be wide.

[0026]

In the fixing device according to the first aspect of the present invention, the bearing for supporting the sliding shaft is a rolling bearing, and the inner ring surface of the rolling bearing and the surface corresponding to the sliding shaft in contact with the surface are respectively provided with shafts. Since the directional groove is provided and configured to engage with each other so as to be slidable in the axial direction, sliding wear is prevented, so that the drive of the fixing device is reliably released.

In the fixing device of the second to fourth aspects, even if the sliding wear occurs, the sliding of the sliding shaft in the thrust direction is not hindered. Therefore, the effect of the first aspect. Similarly to the above, the driving of the fixing device is reliably released.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a known image forming apparatus.

FIG. 2 is a schematic front sectional view of a known fixing device mounted in FIG.

FIG. 3 is a partial schematic end view showing the relationship between a rolling bearing and a sliding shaft.

FIG. 4 is a partial schematic view showing a relationship between a rolling bearing and a sliding shaft, FIG. 4 (a) shows a state before use and FIG.
Indicates the state after wear.

FIG. 5 is a partial schematic perspective view showing a characteristic configuration of the present invention.

6 is a partial schematic cross-sectional view showing an engaged state of the groove shown in FIG.

FIG. 7 is a partial schematic front view showing a characteristic configuration of the invention having another configuration.

FIG. 8 is a partial schematic front view showing a characteristic constitution of the invention having still another constitution.

FIG. 9 is a partial schematic front view showing a characteristic constitution of the invention having still another constitution.

FIG. 10 is a partial schematic front view showing a characteristic configuration of the invention having another configuration similarly.

[Explanation of symbols]

 18 Fixing device 23 Sliding shaft 28 Rolling bearing

Claims (4)

[Claims] 1. A driven gear engageable with a drive gear provided on a main body side of an image forming apparatus, and a sliding shaft which is attached to one end of the driven gear and is slidable in an axial direction and supported by a bearing. And an operating knob provided at the other end of the sliding shaft, and the operating knob slides the sliding shaft in the axial direction to engage the driven gear and the driving gear. In a fixing device for an image forming apparatus capable of releasing, a bearing supporting the sliding shaft is a rolling bearing,
An inner ring surface of the rolling bearing and a surface corresponding to the sliding shaft in contact with the surface are provided with axial grooves, respectively, and are engaged with each other slidably in the axial direction. . 2. A driven gear engageable with a drive gear provided on a main body side of an image forming apparatus, and a sliding shaft which is attached to one end of the driven gear and is slidable in an axial direction and supported by a bearing. And an operating knob provided at the other end of the sliding shaft, and the operating knob slides the sliding shaft in the axial direction to engage the driven gear and the driving gear. In a fixing device for an image forming apparatus capable of releasing, when the bearing that supports the sliding shaft is a rolling bearing, and is released by the operation knob in the region of the sliding shaft that is in contact with the rolling bearing, A fixing device characterized in that the fixing device is tapered so that a gap between a sliding shaft and a rolling bearing becomes larger toward a side opposite to a direction in which the sliding shaft is slid. 3. A driven gear engageable with a drive gear provided on a main body side of an image forming apparatus, and a sliding shaft which is attached to one end of the driven gear and is slidable in an axial direction and supported by a bearing. And an operating knob provided at the other end of the sliding shaft, and the operating knob slides the sliding shaft in the axial direction to engage the driven gear and the driving gear. In the fixing device for an image forming apparatus capable of releasing the above, the bearing that supports the sliding shaft is a rolling bearing, and the surface of the rolling bearing facing the sliding shaft is more worn than the sliding shaft. A fixing device, characterized in that a member made of an easy material is arranged so as to be a clearance against the sliding shaft. 4. A driven gear engageable with a drive gear provided on the main body side of an image forming apparatus, and a sliding shaft which is attached to one end of the driven gear and is slidable in the axial direction and supported by a bearing. And an operating knob provided at the other end of the sliding shaft, and the operating knob slides the sliding shaft in the axial direction to engage the driven gear and the driving gear. In the fixing device for an image forming apparatus capable of releasing the above, the bearing that supports the sliding shaft is a rolling bearing, and a space between the rolling bearing and the sliding shaft is a shrink fit, and a frame on the device body side. A fixing device, in which a member made of a material that is more easily worn than the frame or the rolling bearing is provided between the roller and the rolling bearing so as to form a clearance for the frame or the rolling bearing.