JP6087852B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus is provided with a fixing device that fixes a toner image on a sheet by applying heat and pressure. The fixing device includes a belt fixing method. In the belt fixing method, toner is fixed to a sheet by inserting a sheet carrying an unfixed toner image through a fixing nip formed by an endless belt and a pressure roller pressed against the belt.

  The fixing device described in Patent Document 1 is provided with a belt regulating member that regulates meandering of the belt. When the belt regulating member comes into contact with the belt, the belt is restricted from moving in the axial direction of the roller, thereby suppressing the meandering of the belt.

JP 2006-313256 A

  However, in the fixing device described in Patent Document 1, when a force is applied to the belt in the direction of the rotation axis of the roller, the belt contacts the belt regulating member, and the end portion of the belt is easily damaged.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device and an image forming apparatus that can suppress belt meandering while suppressing damage to the belt.

  The fixing device according to the present invention fixes toner on a recording medium. The fixing device includes a belt, a rotating member, a flange, and a heating unit. The rotating member has an outer peripheral surface. The belt is wound around at least a part of the outer peripheral surface. The rotating member is driven to rotate by the rotation of the belt. The flange is disposed at an end of the rotating member. The heating unit heats the belt. The flange has a flange portion and an expansion portion. The inflating part is connected so as to be orthogonal to the flange part. The expansion part comes into contact with the belt by thermal expansion based on heating from the heating part.

  An image forming apparatus according to the present invention includes the fixing device described above.

  In the fixing device according to the present invention, the expansion portion of the flange contacts the belt by thermal expansion based on the heating from the heating portion. Therefore, when the toner is fixed on the paper, the belt can be prevented from meandering while being prevented from being damaged.

1 is a perspective view of a fixing device according to Embodiment 1 of the present invention. FIG. 3 is a side view illustrating a configuration in the vicinity of a roller of the fixing device according to the first exemplary embodiment of the present invention. It is a perspective view which shows the roller and flange of the fixing device which concern on Embodiment 1 of this invention. FIG. 3 is a perspective view of a flange in the fixing device according to the first embodiment of the present invention. FIG. 3 is a perspective view of a flange and a belt in the fixing device according to the first embodiment of the present invention. FIG. 3 is a schematic side view of a rotation detection unit in the fixing device according to the first exemplary embodiment of the present invention. It is a schematic diagram which shows the image forming apparatus which concerns on Embodiment 2 of this invention. 1 is a schematic diagram illustrating a fixing device according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated.

[Embodiment 1]
A first embodiment of a fixing device 100 according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of a fixing device 100 according to Embodiment 1 of the present invention. FIG. 2 is a side view showing a configuration in the vicinity of the roller 20 of the fixing device 100 according to the first embodiment of the present invention.

  The fixing device 100 includes a belt 10, a roller 20 (rotating member), a flange 30, and a heating unit 40. The fixing device 100 is mounted on, for example, an image forming apparatus. The fixing device 100 heats and pressurizes the paper (recording medium), thereby melting unfixed toner and fixing it to the paper.

  The roller 20 is, for example, a heating roller. The roller 20 is cylindrical. The roller 20 has an outer peripheral surface, and an endless belt 10 is wound around the outer peripheral surface of the roller 20. As the endless belt 10 rotates, the roller 20 is driven to rotate.

  The flange 30 is disposed at the end of the roller 20. Details of the flange 30 will be described later with reference to FIG.

  The heating unit 40 is, for example, a halogen heater, a ceramic heater, or a carbon heater. The heating unit 40 is built in the roller 20. The heating unit 40 heats the belt 10 via the roller 20. The heating unit 40 has a shape extending in the longitudinal direction. The heating unit 40 is disposed so as to be parallel to the rotation axis direction of the roller 20.

  As shown in FIG. 2, the fixing device 100 further includes a fixing roller 22 and a tension roller 24. The belt 10 is wound around the roller 20, the fixing roller 22, and the tension roller 24. A tension is applied to the belt 10 by a tension roller 24.

  In the fixing device 100, a pressure roller adjacent to the roller 22 is rotationally driven by a driving source (not shown). When the pressure roller rotates, the frictional force between the pressure roller and the belt 10 and the frictional force between the belt 10 and the fixing roller 22 act, and the fixing roller 22 is driven to rotate. When the fixing roller 22 is driven to rotate, the belt 10 travels. The belt 10 is maintained at a predetermined temperature by the heating unit 40. A sheet (not shown) is conveyed by the belt 10 maintained at a predetermined temperature and passes through the nip portion. As a result, unfixed toner is pressure-bonded onto the paper. The pressure roller presses the fixing roller 22 to form a nip portion in order to supply a sufficient amount of heat to the paper and unfixed toner.

  The connection between the flange 30 and the roller 20 will be described with reference to FIG. FIG. 3 is a perspective view of the roller 20 and the flange 30.

  Flange 30 is arranged at both ends of roller 20. The roller 20 and the flange 30 are engaged with each other by a projecting engagement portion 34 included in the flange 30.

  The flange 30 in the fixing device 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a perspective view of the flange 30 in the fixing device 100 according to the first embodiment of the present invention.

  The flange 30 includes a flange portion 31 and an expansion portion 33 (a first expansion portion 33a and a second expansion portion 33b). The flange 30 further includes a projecting engagement portion 34, an outer annular engagement portion 35, and an inner annular engagement portion 36. A through hole 37 is formed in the flange 30.

  The flange 31 has a flat surface 31a and an outer peripheral surface 31b. The flat surface 31a is annular. The eaves portion 31 is made of, for example, polyphenylene sulfide (PPS). Teeth 38 are formed on the outer peripheral surface 31 b of the collar portion 31.

The inflatable portion 33 has an arc shape having a smaller diameter than the outer peripheral surface 31 b of the flange portion 31. The flange 30 is provided with a first expansion portion 33a and a second expansion portion 33b. The expansion part 33 expands in the radial direction. The expansion part 33 contacts the back surface of the belt 10 by thermal expansion. The expansion part 33 is connected to the flange part 31 so as to extend in the normal direction of the flat surface 31a. For example, the expansion part 33 is an elastic member. The expansion part 33 is preferably formed of a material having a high thermal expansion coefficient. The inflating part 33 is made of, for example, PPS. The thermal expansion coefficient of the expansion part 33 is 2.6 × 10 ⁻⁵ / K or more and 6.9 × 10 ⁻⁵ / K or less, but 6.0 × 10 ⁻⁵ / K or more and 6.9 × 10 ^−5. / K or less is more preferable. The thermal expansion coefficient of the expansion part 33 is preferably higher than that of the flange part 31. For example, the thermal expansion coefficient of the flange portion 31 is about 5 × 10 ⁻⁵ / K, whereas the thermal expansion coefficient of the expansion portion 33 is 6.9 × 10 ⁻⁵ / K.

  The protruding engagement portion 34 is provided at a position where the end portion of the first expansion portion 33a and the end portion of the second expansion portion 33b face each other. The outer annular engagement portion 35 is provided so as to be connected to the expansion portion 33, and the expansion portion 33 is located between the flange portion 31 and the outer annular engagement portion 35. The inner annular engagement portion 36 is provided on the radially inner side than the expansion portion 33.

  When the flange 30 is attached to the roller 20, the flange 30 is inserted into openings at both ends of the roller 20, and the projecting engagement portion 34, the outer annular engagement portion 35, and the inner annular engagement portion 36 of the flange 30 are inserted into the roller 20. Engage with the back of the. The shaft of the roller 20 passes through the through hole 37. The inner diameter of the through hole 37 is preferably slightly smaller than the outer diameter of the shaft of the roller 20, and the shaft of the roller 20 is press-fitted into the through hole 37 when the flange 30 is attached to the roller 20. When the expansion part 33 thermally expands, the roller 20 and the expansion part 33 come into close contact with each other, so that the displacement of the flange 30 with respect to the roller 20 can be suppressed. Moreover, since the expansion | swelling part 33 does not expand | swell when the heating part 40 does not heat, the attachment to the roller 20 of the flange 30 can be made easy.

  The positional relationship between the flange 30 and the belt 10 in the fixing device 100 according to the present invention will be described with reference to FIG. FIG. 5 is a perspective view of the flange 30 and the belt 10 in the fixing device 100 according to the first embodiment of the present invention.

  The belt 10 is wound around the flange 30 so that the end portion 11 of the belt 10 passes near the center of the inflating portion 33. There is a slight gap between the expanding portion 33 and the belt 10 at room temperature.

  In the fixing device 100, the heating unit 40 heats the belt 10 when unfixed toner is melted and fixed on a sheet. The heating temperature is 180 ° C., for example. When the heating unit 40 and the heated belt 10 heat the expansion unit 33, the expansion unit 33 thermally expands and comes into contact with the belt 10. That is, there is no gap existing between the expanding portion 33 and the belt 10. Thus, during fixing, the expansion portion 33 is thermally expanded in a direction in which the gap between the expansion portion 33 and the belt 10 is eliminated, for example, in the radial direction, and the belt 10 is pressed by the expansion portion 33. Therefore, when fixing the toner image, the belt 10 can meander, that is, the belt 10 can be prevented from moving in the axial direction of the roller 20. As a result, it can suppress that the edge part 11 of the belt 10 contacts the collar part 31. FIG.

  As described above with reference to FIGS. 1 to 5, in the fixing device 100, the expansion portion 33 of the flange 30 contacts the belt 10 by thermal expansion based on the heating from the heating portion 40. Therefore, when the toner image is fixed on the paper, it is possible to prevent the belt 10 from meandering while suppressing the belt 10 from being damaged by the end portion 11 of the belt 10 coming into contact with the collar portion 31.

  Further, when the heating unit 40 heats the belt 10, that is, when the toner image is fixed to the paper, the flange 30 is driven to rotate through the belt 10. Therefore, the meandering of the belt 10 can be suppressed.

  Further, when the thermal expansion coefficient of the expansion portion 33 is higher than that of the flange portion 31, the flange 30 can be easily attached to the roller 20. Further, the belt 10 can be easily wound around the flange 30.

[Rotation detector]
The rotation detector 50 in the fixing device 100 according to the present invention will be described with reference to FIGS. 1, 4, and 6. FIG. 6 is a schematic side view showing the rotation detection unit 50 in the fixing device 100 according to the first embodiment of the present invention. In FIG. 6, the tooth portions of the flange 30, the first idle gear 51, the second idle gear 52, and the actuator gear 53 are omitted in order to prevent the drawing from becoming complicated.

  The fixing device 100 preferably further includes a rotation detection unit 50. The rotation detection unit 50 is disposed close to the flange 30. The rotation detection unit 50 detects the rotation of the flange 30. The rotation detection unit 50 includes a first idle gear 51, a second idle gear 52, an actuator gear 53, and a rotation detection sensor 54. The first idle gear 51 meshes with the flange 30. The second idle gear 52 meshes with the first idle gear 51. The actuator gear 53 meshes with the second idle gear 52. The rotation detection sensor 54 is disposed to face the actuator gear 53. The teeth 38 of the flange 30 are engaged with the first idle gear 51 of the rotation detection unit 50, and the first idle gear 51 is rotated by the rotation of the flange 30.

  A plurality of light shielding plates 53 a for switching the rotation detection sensor 41 between ON and OFF are fixed to the outer peripheral surface of the actuator gear 53 at equal intervals. The rotation detection sensor 54 is, for example, a PI (photo interrupter) sensor. The rotation detection sensor 54 includes a detection unit. The detection unit has opposing inner surfaces that are U-shaped in plan view. A light emitting part and a light receiving part are provided on the inner surfaces facing each other. Since the light shielding plate 53a blocks the optical path of the detection unit, the light reception signal level of the detection unit is switched from High to LOW, and the rotation of the flange 30 can be detected.

  Next, the operation of the rotation detection unit 50 will be described. In the fixing device 100, when the toner image is fixed on the paper, the flange 30 is rotated counterclockwise via the belt 10. As the flange 30 rotates, the first idle gear 51 that meshes with the flange 30 rotates in the clockwise direction. As the first idle gear 51 rotates, the second idle gear 52 rotates counterclockwise. As the second idle gear 52 rotates, the actuator gear 53 rotates clockwise. And since the light-shielding plate 53a passes the detection part of the rotation detection sensor 54 with rotation of the actuator gear 53, a detection signal is transmitted from the rotation detection sensor 54 and rotation of the flange 30 is detected.

  The rotation detection sensor 54 detects the rotation of the flange 30 when detecting a switching portion (edge) of the received light signal level from HIGH to LOW a plurality of times within a predetermined time. In the fixing device 100, when the heating unit 40 heats the belt 10 (for example, at the time of fixing), the flange 30 rotates following the belt 10. In the fixing device 100, when the belt 10 is damaged, the flange 30 rotates abnormally, so that the detection signal from the rotation detection sensor 54 becomes abnormal, and it is possible to detect the damage of the belt 10.

  As described above with reference to FIG. 6, in the fixing device 100, the rotation detection sensor 54 detects the rotation of the flange 30. Therefore, an abnormality in the rotation of the flange 30 can be detected. As a result, damage to the belt 10 can be detected.

[Embodiment 2]
FIG. 7 is a schematic diagram showing an image forming apparatus 200 according to Embodiment 2 of the present invention. The image forming apparatus 200 can be a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions. Hereinafter, the present invention will be described by taking a copying machine as an example of the image forming apparatus 200, but the present invention is not limited to this. The image forming apparatus 200 includes a fixing device 100, an image reading unit 110, and an image forming unit 60. The image forming unit 60 includes a paper feed cassette 120, an image forming unit 130, a toner supply device 140, a paper discharge unit 150, and a paper transport unit 160. The image forming unit 60 forms an image based on the image data read by the image reading unit 110.

  The paper feed cassette 120 contains printing paper P. When copying, the paper P in the paper feed cassette 120 is transported by the paper transport unit 160 so as to be discharged from the paper discharge unit 150 via the image forming unit 130 and the fixing device 100.

  The image forming unit 130 forms a toner image on the paper P. The image forming unit 130 includes a photoreceptor 131, a developing device 132, and a transfer device 133.

  An electrostatic latent image is formed on the photoreceptor 131 by a laser based on the electronic signal of the document image generated by the image reading unit 110. The developing device 132 has a developing roller 121. The developing roller 121 forms a toner image on the photosensitive member 131 by supplying toner to the photosensitive member 131 and developing the electrostatic latent image. The toner is supplied from the toner supply device 140 to the developing device 132.

  The transfer device 133 transfers the toner image formed on the photoconductor 131 onto the paper P.

  By fixing and heating the paper P by the fixing device 100, the unfixed toner formed in the image forming unit 130 is melted and fixed on the paper P.

  The embodiment of the present invention has been described above with reference to the drawings (FIGS. 1 to 7). However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof. In order to facilitate understanding, the drawings schematically show each component as a main component, and the thickness, length, number, and the like of each component shown in the drawings are different from the actual for convenience of drawing. . In addition, the material, shape, dimensions, and the like of each component shown in the above embodiment are merely examples, and are not particularly limited, and various changes can be made without departing from the effects of the present invention. is there.

  (1) In the fixing device 100 described with reference to FIGS. 1 to 7, the flange 30 is provided only on the roller 20 (heating roller), but is not limited thereto. For example, the flange 30 may be provided on either the roller 20 or the fixing roller 22.

  (2) In the fixing device 100 described with reference to FIGS. 1 to 7, the heating unit 40 is built in the roller 20, but the heating unit 40 may be provided outside the roller 20. For example, the belt 10 may be heated by an electromagnetic induction heating (IH: Induction Heating) method in which the heating unit 40 is provided outside the roller 20.

  (3) In the fixing device 100 described with reference to FIGS. 1 to 7, the belt 10 is wound around a plurality of rollers (the roller 20, the fixing roller 22, and the tension roller 24), but is not limited thereto. For example, the belt 10 may be wound around one roller 20 as shown in FIG. FIG. 8 is a schematic diagram showing the fixing device 100 according to the embodiment of the present invention. In the fixing device 100, the belt 10 is wound around the entire outer circumference of the roller 20. The pressure roller 102 is provided adjacent to the roller 20.

  (4) Although the fixing device 100 described with reference to FIGS. 1 to 7 includes the rotation detection unit 50, the rotation detection unit 50 may not be included.

  The present invention can be used in the field of image forming apparatuses.

DESCRIPTION OF SYMBOLS 10 Belt 20 Roller 22 Fixing roller 24 Tension roller 30 Flange 31 ridge part 33 Expansion part 34 Projection engagement part 35 Outer annular engagement part 36 Inner annular engagement part 37 Through-hole 40 Heating part 50 Rotation detection part 51 First idle Gear 52 Second idle gear 53 Actuator gear 53a Light shielding plate 54 Rotation detection sensor 100 Fixing device 200 Image forming device

Claims (6)

A fixing device for fixing toner on a recording medium,
Belt,
A rotating member having an outer peripheral surface, wherein the belt is wound around at least a part of the outer peripheral surface, and rotated by the rotation of the belt;
A flange disposed at an end of the rotating member;
A heating unit for heating the belt,
The flange is
Buttock,
A fixing device, comprising: an expansion portion that is connected so as to be orthogonal to the flange portion and abuts on the belt by thermal expansion based on heating from the heating portion.   The fixing device according to claim 1, wherein the flange rotates following the belt.   The fixing device according to claim 1, wherein a thermal expansion coefficient of the expansion portion is higher than a thermal expansion coefficient of the flange portion.   The fixing device according to any one of claims 1 to 3, further comprising a rotation detection unit that detects rotation of the flange. There are a plurality of the rotating members,
5. The fixing device according to claim 1, wherein the belt is wound around at least a part of an outer peripheral surface of each of the plurality of rotating members. A fixing device according to any one of claims 1 to 5,
An image forming unit for transferring a toner image to a recording medium,
The fixing device fixes the toner image on the recording medium.

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