JP2001092280A - Image-heating device and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-heating device and an image-forming device, constituted so that recording material is prevented from being wound round film, and jamming processing is easily performed. SOLUTION: This image-heating device is provided with a heating unit 31 supported by a stay 33 and heating the recording material S via the rotatable cylindrical film 34, and a pressure member 32 forming a nip part 36 with the unit 31 and depressing the recording material S. In the device, the recording material S is held in the nip part 36 and carried with the rotation of the film 34, so as to heat the image on the recording material. Then, the device is equipped with a separation pawl 41 near the film on a lower downstream side in a film rotating direction than the nip part 36, and an angle formed by the tangent (m) of the film 34 in a state, where the intersection point of the film 34 with the extension of the separation surface 41a of the pawl 41 is set as a contact point (o) with the separation surface 41a being set at 0 deg. to 60 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image heating apparatus and an image forming apparatus having the same.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus equipped with a fixing device using a thin heat-resistant film for fixing an image on a recording sheet such as a copying machine, a printer, and a facsimile machine using electrophotography.

[0002]

2. Description of the Related Art A fixing device using a thin heat-resistant film,
As shown in FIG. 2, a nip 36 is formed by the heating unit 31 and the pressure roller 32, and the recording sheet S passed through the nip 36 is heated and pressed to fix an image on the sheet.

In the apparatus, a semicircular inflection portion which is continuous in the width direction of the recording sheet S is provided on the downstream side of the nip portion of the stay 33 of the heating unit 31, and the thin heat-resistant film 3 is provided.
The recording sheet S that has passed through the nip portion is separated from the thin heat-resistant film 34 by partially increasing the curvature of No. 4. Further, a fixing device cover 35 is provided to prevent a user from directly touching the heating unit 31 and the pressure roller 32.

Conventionally, as shown in FIG. 3, when a jam occurs for some reason and the recording sheet S is in an accordion state in the fixing device cover 35, the destination on the rear end side of the recording sheet S is narrowed, and the recording sheet S is narrowed. S and thin heat-resistant film 34
Cannot be separated, and the thin heat-resistant film 34 and the recording sheet S are kept in close contact with each other via the toner.
4 may rotate and the recording sheet S may enter the nip portion 36 again. Then, the rear end of the recording sheet S and the portion that has reentered the nip portion 36 are adhered by toner as shown in FIG.

Therefore, the gap t between the downstream side of the heating unit 31 and the downstream wall of the fixing device cover 35 is narrowed to prevent the recording sheet S from winding around the thin heat-resistant film 34.

[0006]

However, as the print density on the recording sheet S increases, the thin heat-resistant film 34 and the recording sheet S tend to be hardly separated, and the gap between the thin heat-resistant film 34 and the fixing device cover 35 is increased. Even if the recording sheet S is prevented from being entangled by making it narrow until t comes into contact with the recording sheet S, the recording sheet S shown in FIG.
As shown in FIG. 10, the thin heat-resistant film 34 escapes in a direction to form a gap with the fixing device cover, and the recording sheet S passes through the gap t.
As in the case of the above.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image heating apparatus and an image forming apparatus which can prevent a recording material from being wound around a film and can easily perform jam processing. And

[0008]

An image heating apparatus and an image forming apparatus according to the present invention have the following features to solve the above-mentioned problems.

[1] A heating unit which is supported by a stay and heats a recording material via a rotatable cylindrical film, and a pressing member which forms a nip portion with the heating unit and presses the recording material. An image heating apparatus that heat-processes an image on a recording material by nipping the recording material at the nip portion and transporting the recording material along with the rotation of the film; Comprising a claw, wherein an angle between a tangent of the film and a separation surface having a contact point at an intersection of the separation claw with the film when the separation surface is extended is between 0 ° and 60 °. An image heating device characterized by the above-mentioned.

[2]: The separation surface of the separation claw is a surface that comes into contact with a recording material that has begun to be wound around a film and guides the recording material in a direction away from the film to separate the recording material. The image heating apparatus according to [1].

[3]: A separating inflection portion is provided downstream of the nip portion in the film rotation direction, and the separating claw is disposed downstream of the inflection portion [1] or [2]. ]
An image heating device according to claim 1.

[4]: A separation inflection portion is provided downstream of the nip portion in the film rotation direction, and two inflection portions are provided downstream of the inflection portion.
The image heating apparatus according to [1] or [2], wherein a second separation inflection portion is provided, and the separation claw is disposed downstream of the secondary separation inflection portion.

[5] A heating unit that is supported by the stay and heats the recording material via a rotatable cylindrical film, and a pressing member that forms a nip with the heating unit and presses the recording material. In an image heating apparatus that heat-processes an image on a recording material by nipping the recording material at the nip portion and transporting the recording material along with the rotation of the film, the image heating device contacts the film at a position downstream of the nip portion in the film rotation direction. An angle between a tangent line of the film and a separation surface having a portion where the separation claw and the film contact each other as a contact point is 0 ° or more.
An image heating device, wherein the image heating device is configured to be at an angle of 60 °.

[6]: The separation surface of the separation claw is a surface that comes into contact with the recording material that has begun to be wound around the film and guides the recording material in a direction away from the film to separate the recording material. The image heating device according to [5].

[7]: [5] or [6], wherein a separation inflection portion is provided downstream of the nip portion in the film rotation direction, and the separation claw is arranged downstream of the inflection portion. ]
An image heating device according to claim 1.

[8]: A separation inflection portion is provided downstream of the nip portion in the film rotation direction, and two inflection portions are provided downstream of the inflection portion.
The image heating apparatus according to [5] or [6], wherein a next separation inflection portion is provided, and the separation claw is disposed downstream of the secondary separation inflection portion.

[0017]

[9]: The image heating apparatus according to any one of [5] to [8], wherein the separation claw is in contact with the film by its own weight or a constant force by an elastic member.

[10]: The separation claw is in contact with a slack portion of the film [5] to [5].

The image heating apparatus according to any one of [9].

[11] The image heating method according to any one of [1] to [10], wherein the heating process is a process of thermally fixing an image on a recording material to the recording material. apparatus.

[12]: In an image forming apparatus having an image forming means for forming an image on a recording material and an image heating means for heating the image on the recording material, [1] as the image heating means
An image forming apparatus comprising the image heating device according to any one of the above items [11] to [11].

<Operation> As described above, the angle between the separation surface and the intersection of the extension line and the film or the tangent of the film at the contact point between the separation claw and the film is 0 ° to 60 °.
°, the recording material that has begun to wind around the film can be separated without applying force to the film, so that the thin heat-resistant film is not damaged or excessively worn. In addition, it is possible to prevent the recording material from being wound around the film, and to easily perform the jam processing.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An image heating apparatus to which the present invention is applied and an image forming apparatus equipped with the same as a fixing device will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing a schematic configuration of an electrophotographic printer as the image forming apparatus.

First, a schematic configuration of an electrophotographic printer will be described with reference to FIG. As shown in FIG. 1, the electrophotographic printer 1 uses the charging roller 5 to uniformly charge the surface of the photosensitive drum 2. Next, the laser beam L is irradiated onto the photosensitive drum via the mirror 4 by the laser scanner 3 to image-expose the target image to form a latent image.

Next, the latent image is developed by applying the toner 8 in the developing unit 6 onto the surface of the photosensitive drum via the developing roller 7 to form a toner image. On the other hand, the recording sheets (recording material) S stacked on the paper feed tray 13 are fed one by one by the paper feed roller 12 and the separation pad, and sent to the transport roller pair 11. The recording sheet S is sent from the conveying roller pair 11 to a portion (transfer nip portion) where the transfer roller 10 and the photosensitive drum 2 are opposed to each other, and a transfer bias is applied from the transfer roller 10 to transfer the toner image on the photosensitive drum surface to the recording sheet S. Transcribed above.
The toner 8 transferred to the recording sheet S is fixed by the fixing device 16, and the recording sheet S is discharged out of the main body of the electrophotographic printer by the discharge roller pair 17. On the other hand, photosensitive drum 2
After the transfer, the toner 8 remaining after the transfer is cleaned by the cleaner 9 and the process proceeds to the next stage.

Next, the fixing unit will be described. FIG. 5 is a schematic sectional view of a fixing unit according to the embodiment of the present invention. In the figure, H is a planar heater (ceramic heater in this example) that generates heat when energized, 34 is a thin cylindrical heat-resistant film that is in sliding contact with the heater H, and 33 is a heater that supports the heater H with the heating surface facing downward. In addition, it is a support member (stay) that rotatably supports the thin heat-resistant film 34, and these elements H, 33, and 34 constitute the heating unit 31 of this example. Reference numeral 32 denotes a pressing member (pressing roller) that forms a nip portion 36 by pressing against the heating unit 31.
The pressure roller 32 is driven by a driving means (not shown) to rotate in the counterclockwise direction indicated by an arrow a, and the film 3
4 is driven in the direction of arrow a '.

The recording sheet S on which the toner image is formed is introduced into the nip 36 by the image forming means including the photosensitive drum 2, the laser scanner 3, the developing device 6, the transfer roller 10 and the like. The toner image is heat-fixed to the recording sheet S by the heat from the heater H via the film 34 and the nip pressure.

In such a configuration, if the recording sheet S is not conveyed earlier than the discharge roller pair 17 for some reason, the recording sheet S is set inside the fixing device cover 35 and the discharge roller pair 1.
Between the nip portion 36 and the nip portion 36, the recording sheet S becomes accordion-like, and the destination of the recording sheet S becomes narrower. When the recording sheet S is further conveyed, the recording sheet S and the thin heat-resistant film 34 are not separated by the separating inflection portion 37, and the recording sheet S is
It comes into close contact with and begins to wind.

Therefore, in the present embodiment, a separation claw 41 is provided near the film on the downstream side in the film rotation direction from the nip portion 36, and the separation surface 41a comes into contact with the recording sheet S wound thereon, and the recording sheet S is moved from the film 34 It is guided in the direction of separation and separated.

The separated recording sheet S stays in the pocket between the separation claw 41 and the fixing device cover 35 as shown in FIG. 6, and the recording sheet S having no place to go is in a smaller accordion state. The thin heat-resistant film 34 slips because it is accumulated in the gap between the pressure rollers 32 or there is no space for conveying the recording sheet S, and the conveyance of the recording sheet S stops.

The separation claw 41 does not come into contact with the thin heat-resistant film 34, and extends when the thin heat-resistant film 34 and the separation surface 41a are extended in a plane perpendicular to the rotation axis of the film 34 (ie, in the plane of FIG. 5). The angle θ between the tangent line m having the intersection as the contact point o and the separation surface 41a is arranged to be between 0 ° and 60 °.

The separation claws 41 are arranged at one or more places near the thin heat-resistant film, preferably at four places in the film width direction as shown in FIG.

As described above, according to the present embodiment, the angle between the separation surface 41a and the tangent m of the film 34 at the intersection o between the extension line and the film 34 is between 0 ° and 60 °. Since the recording sheet S that has begun to be wound around the thin heat-resistant film 34 can be separated without applying force to the thin heat-resistant film 34, the thin heat-resistant film 34 may be scratched or excessively worn. Without causing the recording sheet S to wrap around the thin heat-resistant film 34,
It becomes possible for the user to perform jam processing according to the procedure.

<Second Embodiment> Next, a second embodiment will be described with reference to FIG. FIG. 7 is a schematic sectional view of the vicinity of a fixing device according to a second embodiment of the present invention. This embodiment is different from the above-described embodiment in that a separation claw is provided on the downstream side of the secondary separation inflection portion, and the other configuration is the same. For this reason, the same elements are given the same reference numerals, and the description thereof is partially omitted.

If the recording sheet S is not conveyed earlier than the discharge roller pair 17 for some reason, the fixing device cover 35
Inside, and between the discharge roller pair 17 and the nip portion 36, the recording sheet S becomes accordion-like from the discharge roller pair 17 side, and the destination of the recording sheet S narrows.
When the recording sheet S is further conveyed, the thin heat-resistant film 34
Nip 3 of stay 33 that supports and regulates the shape
(6) The recording sheet S and the thin heat-resistant film 34 are not separated by the separation inflection portion 37 of the thin heat-resistant film 34 regulated by the semicircular inflection portion that is continuous in the paper width direction on the downstream side, and As a result, the recording sheet S comes into close contact with the thin heat-resistant film 34 and starts to wind.

Therefore, in this embodiment, the thin heat-resistant film 34 is supported by the stay 33 which regulates the shape, and is controlled by the semi-circular secondary inflection portion which is continuous in the paper width direction. A secondary separation inflection section 38 of the film 34 is provided downstream of the separation inflection section 37 in the film rotation direction, and the recording sheet S that has passed through the separation inflection section 37 starts to be separated from the thin heat-resistant film 34. , And are completely separated by a separation claw 41 disposed further downstream. The separated recording sheet S stays in the separation claw portion as shown in FIG. 8, and the recording sheet S having no place to go is in a smaller accordion state and is accumulated in the gap between the heating unit 31 and the pressure roller 32, or Since there is no more transport space for the recording sheet S, the thin heat-resistant film 34 slips, and the transport of the recording sheet S stops.

Also in the present embodiment, the separation claw 41 is not in contact with the thin heat-resistant film 34, and the tangent m and the separation surface of the separation claw 41 are used as a contact point at the intersection when the thin heat-resistant film 34 and the separation surface 41a are extended. The angle θ made with 41a is 0 °
It is arranged so as to be between ６０60 °. The separation claws 41 are arranged at two or more places on the thin heat-resistant film.

As described above, according to the present embodiment, the separation claw 41 is provided in the vicinity of the thin heat-resistant film 34 on the downstream side of the secondary separation inflection portion, and the separation surface 41a of the separation claw 41 and the tangent m
By making the angle between 0 ° and 60 °, it is not necessary to apply force to the thin heat-resistant film 34, without causing scratches or excessive wear on the thin heat-resistant film 34, The recording sheet S that has begun to be wound around the thin heat-resistant film 34 can be reliably separated, and the user can perform the jam processing according to the procedure.

Third Embodiment Next, a third embodiment will be described with reference to FIG. FIG. 11 shows a third embodiment according to the present invention.
FIG. 4 is a schematic cross-sectional view of the vicinity of a fixing device according to the embodiment. This embodiment is different from the above-described embodiment in that the separation claw is in contact with the slack portion of the film, and the other configuration is the same. For this reason, the same elements are given the same reference numerals, and the description thereof is partially omitted.

If the recording sheet S is not conveyed earlier than the discharge roller pair 17 for some reason, the fixing device cover 35
Inside, and between the discharge roller pair 17 and the nip portion 36, the recording sheet S becomes accordion-like from the discharge roller pair 17 side, and the destination of the recording sheet S narrows.
When the recording sheet S is further conveyed, the thin heat-resistant film 34
Nip 3 of stay 33 that supports and regulates the shape
(6) The recording sheet S and the thin heat-resistant film 34 are not separated by the separation inflection portion 37 of the thin heat-resistant film 34 regulated by the semicircular inflection portion that is continuous in the paper width direction on the downstream side, and As a result, the recording sheet S comes into close contact with the thin heat-resistant film 34 and starts to wind.

The recording sheet S, which has begun to be wound, is slackened with the stay 33 of the thin heat-resistant film 34 (film 34).
Abuts on stay 33) 5g / cm
The tip of the separation claw and the thin heat-resistant film 3 are in contact with each other and in a plane perpendicular to the film rotation axis (that is, in the plane of FIG. 11).
The thin heat-resistant film 34 and the recording sheet S are separated by the separation claw 41 arranged at an angle θ between the tangent line m of the film 34 having the contact portion 4 as the contact point o and the separation surface 41a between 0 ° and 60 °. Separated. The separated recording sheet S is shown in FIG.
2, the recording sheet S stays in the pocket between the separation claw 41 and the fixing device cover 35, and the recording sheet S having no place to go is in a smaller accordion state. The thin heat-resistant film 34 slips due to the accumulation or the space for conveying the recording sheet S running out, and the conveyance of the recording sheet S stops.

The separating claw 41 is placed on a thin heat-resistant film.
It is arranged at a plurality of positions, preferably in a plurality of positions, arranged in the film rotation axis direction.

As described above, according to this embodiment, the separation claw 4
1 has a contact force of 5 g / on the slack portion of the thin heat-resistant film 34.
cm, the tangent line m at the contact point o and the separation claw 4
By disposing the separation claws 41 so that the angle between the first heat-resistant film 41 and the separation surface 41a is between 0 ° and 60 °, the thin heat-resistant film 34 does not need to be subjected to excessive force. Preventing the recording sheet S from being wound around the thin heat-resistant film 34 without causing scratches or excessive wear on
It becomes possible for the user to perform jam processing according to the procedure.

[0043]

As described above, according to the present invention, it is possible to provide an image heating apparatus and an image forming apparatus which can prevent a recording material from being wound around a film and can easily carry out jam processing.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing a schematic configuration of an electrophotographic printer.

FIG. 2 is a schematic side sectional view of a conventional example.

FIG. 3 is a schematic side sectional view showing a state where a recording sheet is wound around a heating unit.

FIG. 4 is a schematic cross-sectional view showing a state where a recording sheet has begun to be wound by deforming a thin heat-resistant film.

FIG. 5 is a schematic side sectional view according to the first embodiment of the present invention.

FIG. 6 is a schematic side sectional view according to the first embodiment of the present invention.

FIG. 7 is a schematic side sectional view according to a second embodiment of the present invention.

FIG. 8 is a schematic side sectional view according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram showing the arrangement of the separation claw according to the present invention in the film longitudinal direction (recording material width direction).

FIG. 10 is an explanatory diagram illustrating a state in which the toner on the wound recording sheet and the toner on the recording sheet before fixing are adhered to each other;

FIG. 11 is a schematic side sectional view according to a third embodiment of the present invention.

FIG. 12 is a schematic side sectional view according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic printer 2 Photosensitive drum 3 Laser scanner 4 Mirror 5 Charging roller 6 Developing device 7 Developing roller 8 Toner 9 Cleaner 10 Transfer roller 11 Conveyance roller pair 12 Paper feed roller 13 Paper feed tray 16 Fixing device 17 Discharge roller pair 31 Heating Unit 32 Pressure roller 33 Stay 34 Thin heat-resistant film 35 Fixer cover 36 Nip part 37 Separation inflection part 38 Secondary separation inflection part 41 Separation claw 41a Separation surface H Heater L Laser beam S Recording sheet m Tangent line o Contact θ Tangent line And the angle between the separation surface and the separation claw

Claims (12)

[Claims] 1. A heating unit which is supported by a stay and heats a recording material via a rotatable cylindrical film, and a pressing member which forms a nip portion with the heating unit and presses the recording material. An image heating apparatus that heats an image on a recording material by nipping the recording material at the nip portion and transporting the recording material along with the rotation of the film; wherein a separation claw is provided near the film on the film rotation direction downstream side of the nip portion. Wherein the angle between the tangent line of the film and the separation surface, where the intersection of the separation claw and the film when the separation surface of the separation claw is extended, is a contact point, is between 0 ° and 60 °. Image heating device. 2. The separation surface of the separation claw is a surface that comes into contact with a recording material that has begun to be wound around a film and guides and separates the recording material in a direction away from the film. The image heating device according to claim 1. 3. The separating nip according to claim 1, wherein a separating inflection portion is provided downstream of the nip portion in the film rotation direction, and the separation claw is disposed downstream of the inflection portion. Image heating device. 4. A separation inflection portion is provided downstream of the nip portion in the film rotation direction, a secondary separation inflection portion is provided downstream of the inflection portion, and a downstream side of the secondary separation inflection portion. The image heating device according to claim 1, wherein the separation claw is disposed on the image heating device. 5. A heating unit supported by a stay and heating a recording material via a rotatable cylindrical film, and a pressing member forming a nip portion with the heating unit and pressing the recording material. An image heating apparatus that heats an image on a recording material by nipping the recording material at the nip portion and transporting the recording material together with the rotation of the film, wherein the separation claw is in contact with the film on the downstream side in the film rotation direction from the nip portion. Image heating, wherein an angle between a tangent line of the film and a separation surface having a contact point between the separation claw and the film as a contact point is between 0 ° and 60 °. apparatus. 6. The separation surface of the separation claw is a surface that comes into contact with a recording material that has begun to be wound around a film, and guides and separates the recording material in a direction away from the film. 7. The image heating device according to 6. 7. The separation inflection portion provided downstream of the nip portion in the film rotation direction, and the separation claw is disposed downstream of the inflection portion. Image heating device. 8. A separation inflection portion is provided downstream of the nip portion in the film rotation direction, a secondary separation inflection portion is provided downstream of the inflection portion, and a downstream side of the secondary separation inflection portion. The image heating apparatus according to claim 5, wherein the separation claw is disposed on the image heating device. 9. The image heating apparatus according to claim 5, wherein the separation claw is in contact with the film by its own weight or a constant force by an elastic member. 10. The image heating apparatus according to claim 5, wherein the separation claw is in contact with a slack portion of the film. 11. The image heating apparatus according to claim 1, wherein the heating process is a process of thermally fixing an image on a recording material to the recording material. 12. An image forming apparatus having an image forming means for forming an image on a recording material and an image heating means for heating the image on the recording material, wherein the image heating means is used as an image heating means. An image forming apparatus comprising the image heating device according to claim 1.