JP3040595B2 - Electrophotographic device fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system (such as a printer, a copying machine, a facsimile, etc.) using a laser (an image formed on a photoreceptor is transferred to a sheet, and then the image is fixed and recorded). Method), it can be applied to an electrophotographic apparatus for recording on a sheet. More specifically, the present invention relates to a fixing device that rotates a fixing rotating member such as a fixing roller and a fixing belt in such an electrophotographic apparatus, contacts the image surface of an image-transferred sheet, and fixes a toner image on the image surface.

[0002]

2. Description of the Related Art Conventionally, in a fixing device of this type, as shown in FIG. 8, for example, a pressing roller 1 is urged by an urging spring 2 to be pressed against a fixing roller 3 and the fixing roller 3 is pressed. There is a type in which the fixing cleaning roller 4 impregnated with oil is urged by urging springs 5 and 6 and pressed. The fixing cleaning roller 4 has a rotation transmission gear 8 that meshes with a fixing gear 7 integrated with the fixing roller 3 at one end of the roller shaft 4a, and transmits a driving force to the fixing roller 3 through the meshing. And was free to rotate.

In this conventional fixing device, at the time of fixing, the driving force is transmitted to rotate the fixing cleaning roller 4 together with the fixing roller 3, and the sheet S after image transfer is transferred between the fixing roller 3 and the pressure roller 1. To fix the toner image on the sheet S while the fixing cleaning roller 4 forms an oil film on the surface of the fixing roller 3 to prevent the toner from adhering to the surface of the fixing roller 3 during fixing. This prevents the adhered toner from contaminating the image surface of the sheet S being fed.

[0004]

However, in the above-mentioned conventional fixing device, the fixing gear 7 and the rotation transmitting gear 8 are fixed at the time of fixing.
The upward force F of the driving force acts on the fixing cleaning roller 4 through the engagement of the fixing cleaning roller 4 to push up one side of the fixing cleaning roller 4, so that the fixing cleaning roller 4 cannot be uniformly pressed against the fixing roller 3. Was.

An object of the present invention is to make it possible to evenly press a fixing cleaning roller against a fixing roller in the above-described fixing device.

[0006]

Accordingly, the present invention provides
For example, as shown in the following illustrated embodiment, the fixing cleaning roller 40 is urged and pressed against a fixing rotating member such as the fixing roller 30, and the driving force to the fixing rotating member is then transmitted to the fixing rotating member via a rotation transmitting unit 45. In the fixing device 20 of the electrophotographic apparatus, which transmits to the fixing cleaning roller 40 and rotates the fixing cleaning roller 40 together with the fixing rotating member to clean the surface of the fixing rotating member, the fixing rotating member and the fixing cleaning roller 4
The rotation transmission means 45 is provided at both ends of the zero.

The fixing device according to the second aspect of the present invention is, for example, as shown in the following embodiment shown in the drawings.
, Wherein the rotation transmitting means 45 is constituted by elastic rotating members 33 and 41 that come into frictional contact.

According to a third aspect of the present invention, there is provided a fixing device 20 according to the first aspect, for example, as shown in the following illustrated embodiments.
, Wherein the rotation transmitting means 45 is constituted by meshing elastic rotating members 33 and 41.

[0009]

[Function] At the time of fixing, the driving force to the fixing rotating member is
Then, the fixing rotating member and the fixing cleaning roller 4
And 0 is transmitted to the fixing cleaning roller 40 via the respective rotation transmitting means 45 at both ends.

According to the second aspect, at the time of fixing,
The elastic rotating members 33 and 41 come into frictional contact with each other and transmit the driving force to the fixing rotating member to the fixing cleaning roller 40, while the force acting on the fixing cleaning roller 40 from the fixing rotating member based on the driving force is transmitted to the elastic rotating member. 33 ・
It absorbs to some extent due to the elasticity of 41.

According to the third aspect, at the time of fixing,
While the driving force to the fixing rotating member is transmitted to the fixing cleaning roller 40 by the engagement of the elastic rotating members 33 and 41, the force acting on the fixing cleaning roller 40 from the fixing rotating member based on the driving force is transmitted to the elastic rotating members 33 and 41. 4
1 absorbs to some extent.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 shows a laser printer having a fixing device according to an embodiment of the present invention, and shows an overall schematic configuration of an internal mechanism thereof. In the figure, reference numeral 10 denotes an apparatus main body. A drum-shaped photoconductor 11 that rotates clockwise in the figure is provided in the center of the apparatus main body 10. Around the photoreceptor 11, a charger 12 and an optical writer 1 are sequentially arranged in the rotation direction.
3. A developing device 14, a transfer device 15, and a cleaning device 16 are arranged.

On the other hand, on the right side of the apparatus main body 10 in the figure, sheet cassettes 17 containing sheets S are detachably mounted in two upper and lower stages. On the right side of the transfer device 15,
The registration roller pair 18 is disposed. On the other hand, on the side opposite to the registration roller 18 with the transfer unit 15 therebetween,
And the fixing device 20 of the present invention are arranged in order.

In the illustrated laser printer, the sheet feeding rollers 22 are appropriately selected and driven, and the sheets S are sequentially sent out from the sheet feeding cassette 17 and are brought into contact with the registration roller 18 to be brought into contact therewith. stop.

On the other hand, the surface of the photosensitive member 11 is sequentially charged by the charger 12 while rotating clockwise in the drawing, and the next light writer 13 irradiates laser light to irradiate the surface with an electrostatic latent. An image is formed, and then the electrostatic latent image is sequentially visualized as it passes by the position of the developing device 14. Then, the registration roller 18 is driven in synchronization with the image and the sheet S is transferred to the photosensitive member 1.
Send out to one. Then, the visible image on the photoconductor 11 is transferred to the surface of the sheet S by the transfer device 15. After the transfer, the surface of the photoconductor 11 is cleaned by the cleaning device 16, while the sheet S is sent to the fixing device 20 by the transport device 19, and the transferred image is fixed by the fixing device 20. Then, the sheet is discharged to the sheet discharge stack section 26 through the sheet discharge path 25.

Incidentally, the above-mentioned fixing device 20 has a structure as shown in FIG. 1 in detail. Reference numeral 30 in the figure denotes a fixing roller. The fixing roller 30 includes a heater (not shown).
And a drive transmission gear 3 at one end of a roller shaft (not shown).
A fixing gear 32 that meshes with the fixing gear 1 is attached. Further, the fixing roller 30 is provided with a band-shaped elastic rotating member 33 on the outer periphery of both ends. The elastic rotating member 33 is formed of silicon rubber or the like having a rough surface (having a coefficient of friction of 0.8 or more).

The fixing device 20 includes a fixing roller 30.
A pressure roller 35 is disposed below the pressure roller 35.
Is urged by the urging spring 36 and pressed against the fixing roller 30.

Further, in the fixing device 20, a fixing cleaning roller 40 impregnated with silicon oil or the like is disposed above the fixing roller 30. Fixing cleaning roller 40
The disk-shaped elastic rotating members 41 are attached to both ends of the roller shaft 40a. The elastic rotating member 41 is formed of silicon rubber or the like whose outer peripheral surface is coarsely formed in the same manner as the elastic rotating member 33. Then, the fixing cleaning roller 4
Reference numeral 0 indicates that the elastic rotating member 41 is pressed against the elastic rotating member 33 on the fixing roller 30 side while being urged by the urging springs 42 at both ends of the roller shaft 40a and pressed against the fixing roller 30. Thus, the rotation transmitting means 45 is constituted by the elastic rotating members 33 and 41 which come into frictional contact with each other.

In the fixing device 20 described above, at the time of fixing an image, the driving force of the driving motor is transmitted through the engagement between the driving transmission gear 31 and the fixing gear 32 to rotate the fixing roller 30. Then, the pressure roller 35 is driven to rotate, and heat and pressure are applied to the post-image transfer sheet S between the two rollers 30 and 35 to fix the toner image on the sheet S.
At the same time, the driving force to the fixing roller 30 is transmitted to the fixing cleaning roller 40 via the two elastic rotating members 33 and 41 that come into frictional contact, and the fixing cleaning roller 40 rotates. At this time, the force acting on the fixing cleaning roller 40 from the fixing roller 30 based on the driving force is absorbed to some extent by the elasticity of the elastic rotating members 33 and 41, and it is prevented that the fixing cleaning roller 40 is pushed up by the force. Then, silicone oil is applied to the surface of the fixing roller 30 by the fixing cleaning roller 40 to form an oil film, and the toner is prevented from adhering to the surface of the fixing roller 30 during the fixing.

Incidentally, in the illustrated embodiment described above, the elastic rotating members 33 and 41 are each formed of silicon rubber or the like whose surface is roughened. However, as shown in FIG. 2, for example, such elastic rotating members 33 and 41 may be formed in a flat knurled shape with their surfaces being uniformly uneven, so as to increase the elasticity.

At the time of fixing, the elastic rotating members 33
41, the driving force to the fixing roller 30 is transmitted to the fixing cleaning roller 40 through frictional contact between the convex portions 33a and 41a of the fixing member 40, and the force acting on the fixing cleaning roller 40 from the fixing roller 30 based on the driving force is It is absorbed to some extent by the elasticity of the elastic rotating members 33 and 41.

In the embodiment shown in FIG. 2, each surface of the elastic rotating members 33 and 41 constituting the rotation transmitting means 45 is formed in a flat knurled shape. However, for example, FIG.
As shown in (1), the surface of the elastic rotating members 33 and 41 may be formed relatively large in irregularities, and the protrusions 33a and 41a may be provided with holes 33b and 41b, respectively, to further increase the elasticity. Further, as shown in FIG. 4, for example, holes 33b and 4 of similar elastic rotating members 33 and 41 are provided.
1b may be provided slightly near the center of rotation of the projections 33a and 41a.

Further, in the illustrated embodiment described above, the rotation transmitting means 45 is constituted by both elastic rotating members 33 and 41. However, as in the embodiment shown in FIG. 5, an elastic rotating member 41 made of an elastic body such as a rubber roller is provided at both ends of the roller shaft 40a of the fixing cleaning roller 40, while elasticity is provided at both ends of the fixing roller 30. A belt-shaped knurled surface 50 not provided may be provided. The rotation transmitting means 45 is constituted by the elastic rotating member 41 and the knurl surface 50 which comes into frictional contact with the elastic rotating member 41.

However, in another embodiment, at the time of fixing,
The frictional contact between the elastic rotating member 41 and the knurled surface 50 causes the driving force to the fixing roller 30 to be applied to the fixing cleaning roller 4.
To the fixing roller 3 based on the driving force.
From 0, the force acting on the fixing cleaning roller 40 is absorbed to some extent by the elasticity of the elastic rotating member 41.

By the way, in the illustrated embodiment described above, the rotation transmitting means 45 is constituted by an elastic rotating member which comes into frictional contact.
However, as in the embodiment shown in FIG. 6, for example, the rotation transmitting means 45 may be constituted by elastic rotating members 33 and 41 which mesh with each other.

In another embodiment, the elastic rotating member 3
A plurality of blades 33c and 41c are provided on each of the surfaces 3 and 41 so as to extend in the radial direction. At the time of fixing, the driving force to the fixing roller 30 is transmitted to the fixing cleaning roller 40 via the engagement of the blades 33c and 41c, and the force acting on the fixing cleaning roller 40 from the fixing roller 30 based on the driving force is It absorbs to some extent by the elasticity of the blades 33c and 41c.

[0027]

Therefore, according to the present invention, the fixing cleaning roller is urged and pressed against the fixing rotating member.
In the fixing device that transmits the driving force to the fixing rotating member to the fixing cleaning roller via the rotation transmitting unit, the rotation transmitting unit is provided at both ends of the fixing rotating member and the fixing cleaning roller. The fixing cleaning roller can be evenly pressed against the fixing rotating member without pushing up one end of the fixing cleaning roller based on the driving force.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a fixing device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another example of a rotation transmitting unit of the fixing device.

FIG. 3 is a configuration diagram showing another example of the rotation transmitting means.

FIG. 4 is a configuration diagram showing still another example of the rotation transmitting means.

FIG. 5 is a perspective view of a main part of a fixing device according to another embodiment of the present invention in which one of the rotation transmitting means is constituted by an elastic rotating member.

FIG. 6 is a perspective view of a main part of a fixing device according to still another embodiment of the present invention, in which the rotation transmitting means is constituted by a meshing elastic rotating member.

FIG. 7 is an overall schematic configuration diagram showing an internal mechanism of a laser printer including the fixing device of the present invention.

FIG. 8 is a perspective view of a conventional fixing device.

[Explanation of symbols]

 Reference Signs List 20 fixing device 30 fixing roller (fixing rotating member) 33 elastic rotating member of fixing roller 40 fixing cleaning roller 41 elastic rotating member of fixing cleaning roller 45 rotation transmitting means

Claims (3)

(57) [Claims] The fixing cleaning roller is urged and pressed against a fixing rotating member, and a driving force to the fixing rotating member is transmitted to the fixing cleaning roller via rotation transmitting means, and the fixing cleaning roller is moved together with the fixing rotating member. A fixing device for an electrophotographic apparatus that rotates a fixing cleaning roller, wherein the rotation transmitting unit is provided at both ends of the fixing rotating member and the fixing cleaning roller. 2. The fixing device for an electrophotographic apparatus according to claim 1, wherein said rotation transmitting means is constituted by an elastic rotating member that makes frictional contact. 3. The fixing device of an electrophotographic apparatus according to claim 1, wherein said rotation transmitting means is constituted by a meshing elastic rotating member.