JP6015326B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device that thermally fixes an unfixed image using a resistance heating layer that generates Joule heat by energization, and an image forming apparatus having such a fixing device.

2. Description of the Related Art In electrophotographic image forming apparatuses such as printers and copiers, a fixing device that thermally fixes a toner image transferred to a recording sheet such as plain paper or an OHP sheet is provided.
Patent Document 1 discloses a fixing device using an endless heat generating belt having a resistance heat generating layer that generates heat when energized. In this fixing device, the peripheral length of the heat generating belt is longer than the peripheral length of the outer peripheral surface of the fixing roller disposed in the circular movement area, and the fixing roller (elastic roll) and the circulation path of the heat generating belt A part of the heat generating belt in the circumferential direction is sandwiched by a pressure roller (pressure roll) arranged on the outer side, and the heat generating belt is rotated (rotated). In this case, the outer peripheral surface of the heat generating belt and the outer peripheral surface of the pressure roller are in pressure contact with each other, and a fixing nip through which the recording sheet passes is formed at the pressure contact portion.

  In addition, an electrode layer is provided at each end on both sides in the belt width direction of the heat generating belt (the rotation axis direction of the heat generating belt), and power supply members such as a power supply roll and a conductive brush are provided on each electrode layer. It is in pressure contact. With such a configuration, when a current is supplied to one power supply member, the current flows from the power supply member through the resistance heating layer to the other power supply member. As a result, the resistance heating layer generates heat.

  In the fixing device disclosed in Patent Document 1, when the power feeding member is separated from the power receiving member due to the displacement or deformation of the heat-generating belt that circulates, there is a possibility that spark is generated due to a potential difference between the power feeding member and the power receiving member. In this case, when the power receiving member is stacked on the resistance heating layer, high heat generated by the spark is directly transmitted to the resistance heating layer stacked on the power receiving member. As a result, the resistance heating layer becomes hot and thermally expands, and there is a possibility that peeling, breakage, or the like may occur in the laminated portion of the resistance heating layer and the power receiving member.

  For such a problem, each of the pair of power receiving members for supplying power to the resistance heating layer is formed in a cylindrical shape by a metal sheet, and one end portion (base end portion) of each power receiving member is heated by resistance heating. The layers are laminated at both ends of the belt in the belt width direction, and the other end (tip) is extended outward from the resistance heating layer so as not to be laminated with the resistance heating layer. It has been proposed.

  In the heat generating belt configured as described above, each of the power supply members is pressed into contact with a portion of each power receiving member that is not laminated with the resistance heat generating layer. Thereby, even if a spark occurs between the power supply member and the power receiving member, the heat of the spark is not directly transmitted to the resistance heating layer, and there is no possibility that the resistance heating layer is damaged by the high heat of the spark.

JP 2009-109997 A

  As described above, if the peripheral length of the heat generating belt is longer than the peripheral length of the outer peripheral surface of the fixing roller, the heat generating belt may move (meander) in the belt width direction when the heat generating belt rotates. For this reason, there may be a configuration in which a restricting member for preventing the heat generating belt from moving in the belt width direction beyond an allowable range is provided outside the respective end portions on both sides in the belt width direction of the heat generating belt.

When such a restricting member is provided, when the heat generating belt moves in the belt width direction over the maximum allowable range, each end of the heat generating belt on both sides in the belt width direction corresponds to each opposing restricting member. Therefore, the belt is restricted from moving in the belt width direction beyond the allowable range.
Therefore, as described above, when the power receiving members are provided at both ends of the heat generating belt in the belt width direction, when the rotating heat generating belt moves to one of the regulating members, the belt in the power receiving member The tip portions located on both outer sides in the width direction come into contact with the regulating member in a part in the circumferential direction.

In this case, a force along the rotation direction is applied to the restricting member from the contact portion at the distal end portion of the power receiving member that is in a rotating state, and the contact portion with the restricting member at the distal end portion of the power receiving member is A force (reaction force) in a direction opposite to the rotation direction of the power receiving member acts from the member. This reaction force generates a pulling force along the circumferential direction at the contact portion of the power receiving member with the regulating member.
Since the resistance heat generating layer is not laminated at the tip of the power receiving member, the strength against the tensile force along the circumferential direction (tensile strength) is low. For this reason, when a tensile force along the circumferential direction is repeatedly applied to the tip of the power receiving member, the mechanical strength of the power receiving member is locally reduced in a relatively short period of time, and the power receiving member has an axial direction. There is a risk of cracking along. When such a crack occurs in the power receiving member, it becomes impossible to maintain stable contact with the power feeding member.

  The present invention has been made in view of such a problem, and an object of the present invention is to prevent damage to the resistance heating layer due to sparks generated between the power receiving member and the power feeding member. It is an object of the present invention to provide a fixing device capable of restricting the movement of the heat generating belt beyond an allowable range while preventing damage to the image forming apparatus and an image forming apparatus including the fixing device.

In order to achieve the above object, a fixing device according to the present invention is a sheet on which an unfixed image is formed by pressing a pressing member on the outer peripheral surface of an endless heating belt having a resistance heating layer to form a fixing nip. Is a fixing device that thermally fixes the unfixed image while passing through the fixing nip, and is a cylindrical power receiving member disposed on each side of the heat generating belt in the belt width direction. A pair of power receiving members in which one end portion of the member is joined to each end portion on both sides in the belt width direction of the resistance heating layer in a conductive state, and the other end portion is positioned on both outer sides of the resistance heating layer; A pair of power supply members slidably in contact with the outer peripheral surface or the inner peripheral surface of the other end of each power receiving member, and the other power receiving member in order to restrict movement of the heat generating belt in the belt width direction. end When the rotating heating belt moves in the belt width direction, the other end of the power receiving member from the tip end surface of the other end when the rotating heat generating belt moves in the belt width direction. to contact toward one or both of the outer and inner peripheral surfaces of parts, have a, a contact member provided on said regulating member, the contact member along the circumferential direction of the power receiving member contiguous The contact member is characterized in that a cut from the outer peripheral surface is provided along the axial direction in at least one circumferential direction of the contact member .
Further, a pressing member is pressed on the outer peripheral surface of an endless heat generating belt having a resistance heating layer to form a fixing nip, and the unfixed image is formed while the sheet on which the unfixed image is formed passes through the fixing nip. A cylindrical power receiving member disposed on both sides of the heat generating belt in the belt width direction, wherein one end of each power receiving member is a belt in the resistance heat generating layer. A pair of power receiving members that are joined in conductive state to the respective ends on both sides in the width direction and the other ends are positioned on both outer sides of the resistance heating layer, and the outer peripheral surface of the other end of each power receiving member Alternatively, a pair of power supply members slidably in contact with the inner peripheral surface, and a pair of restriction members disposed to face the other end of each power receiving member in order to restrict movement of the heat generating belt in the belt width direction. Part And when the rotating heat generating belt moves in the belt width direction, either the outer peripheral surface or the inner peripheral surface of the other end of the power receiving member from the front end surface of the other end of the power receiving member Or a contact member provided on the restricting member so as to be in contact with both, wherein a plurality of the contact members are provided at intervals in the circumferential direction of the power receiving member. .

  Furthermore, an image forming apparatus of the present invention includes the fixing device.

In engagement shall be specified destination device in the present invention, the contact member provided on the regulating member, to contact with either or both of the outer and inner peripheral surfaces of the other end of the receiver member, the contact member and the receiving The contact area with the member is increased as compared with the case where only the end surface of the other end of the power receiving member is in contact with the regulating member. As a result, the frictional force acting between the rotating power receiving member and the contact member provided on the rotation stopped regulating member increases, and the contact member moves quickly and integrally with the power receiving member. As a result, the regulating member provided with the contact member quickly rotates integrally with the power receiving member.

  In this way, when the power receiving member comes into contact with the contact member, the regulating member quickly rotates integrally with the power receiving member, so that the rotating power receiving member is prevented from sliding with the rotation stopped contact member. Therefore, it is possible to suppress the circumferential tensile force from acting on the power receiving member. Thereby, even if contact with a power receiving member and a contact member is repeated, there is no possibility that a crack will occur in a power receiving member in a short period of time, and stable contact with a power feeding member can be maintained.

Preferably, the contact member is constituted by an elastic body that is in a state of being bitten by contact of the other end of the power receiving member.
Preferably, in the contact member, a surface of the power receiving member facing the other end is inclined with respect to a belt width direction of the heat generating belt .

FIG. 3 is a schematic diagram for explaining a configuration of a printer that is an example of an image forming apparatus provided with a fixing device according to an embodiment of the present invention. FIG. 3 is a schematic perspective view for explaining an internal configuration of a fixing device provided in the printer. FIG. 3 is a schematic cross-sectional view for explaining the configuration of the fixing device. FIG. 3 is a longitudinal sectional view of one end portion in an axial direction (belt width direction) of a heat generating belt and a fixing roller provided in the fixing device. It is a longitudinal cross-sectional view in the edge part of the both sides of the width direction of a heat generating belt. In this embodiment, it is an end elevation of the contact member in the state in which the contact member of the modification is provided at the tip of the power receiving member. In this embodiment, it is an end elevation of the contact member of another modification provided in the front-end | tip part of a power receiving member. In this embodiment, it is a longitudinal cross-sectional view of the edge part of the heat generating belt provided with the contact member of another modification. It is an end view which shows the front end surface of the power receiving member shown by FIG. It is a longitudinal cross-sectional view of the end part of one control member and heat generating belt in still another embodiment of the present invention. It is an end elevation which shows the end surface by the side of the heat generating belt in the control member shown by FIG. In this embodiment, it is an end view which shows the front end surface of the power receiving member provided with the contact member of the modification. In this embodiment, it is an end elevation which shows the front end surface of the power receiving member in which the contact member of another modification is provided.

Hereinafter, embodiments of a fixing device and an image forming apparatus according to the present invention will be described.
[Embodiment 1]
<Image forming apparatus>
FIG. 1 is a schematic diagram for explaining a configuration of a printer that is an example of an image forming apparatus provided with a fixing device according to an embodiment of the present invention. This printer forms a monochrome toner image on a recording sheet such as plain paper or an OHP sheet.

The printer shown in FIG. 1 includes a photosensitive drum 11 that is rotationally driven in a direction indicated by an arrow A, and a toner image is formed on the recording sheet S around the photosensitive drum 11 by an electrophotographic method. The charging device 12, the exposure device 13, the developing device 14, and the transfer roller 15 are provided in the order along the rotation direction of the photosensitive drum 11.
The surface of the photosensitive drum 11 in a rotating state is charged to a predetermined potential by the charging device 12 after the residual charge is removed by the static eliminator 18 disposed on the upstream side of the charging device 12. Thereafter, the surface of the photosensitive drum 11 is exposed by the laser light L emitted from the exposure device 13. The exposure device 13 is provided with a laser diode that irradiates a laser beam L. The laser diode is driven by a control unit (not shown) based on image data input from an external device and irradiates the laser beam L. To do.

When the surface of the photosensitive drum 11 is exposed by the laser light L emitted from the exposure device 13, an electrostatic latent image is formed on the surface of the photosensitive drum 11.
A developing device 14 that develops an electrostatic latent image formed on the surface of the photosensitive drum 11 is located downstream of the position on the photosensitive drum 11 where the laser light L is irradiated. It is provided facing the surface. The electrostatic latent image formed on the surface of the photosensitive drum 11 is developed with toner in the developing device 14 and visualized as a toner image.

  Below the photosensitive drum 11, a recording sheet cassette 21 capable of storing a plurality of recording sheets S such as plain paper and OHP sheets is provided, and the recording sheet S stored in the recording sheet cassette 21 is fed. The sheet is fed out one by one by the roller 22. The recording sheet S fed out from the recording sheet cassette 21 is conveyed toward the photosensitive drum 11 by a timing roller pair 23 at a predetermined timing.

  A transfer roller 15 that rotates in the direction of arrow B is provided on the side of the photoconductive drum 11 in a state of being pressed against the photoconductive drum 11, and the transfer nip Nt between the transfer roller 15 and the photoconductive drum 11. Is formed. The recording sheet S fed out from the recording sheet cassette 21 is conveyed to the transfer nip Nt by the timing roller pair 23 and passes through the transfer nip Nt.

  While the recording sheet S passes through the transfer nip Nt, the toner image on the photosensitive drum 11 is transferred onto the recording sheet S by the action of the transfer electric field generated by the transfer voltage applied to the transfer roller 15. . The recording sheet S to which the toner image has been transferred is peeled off from the photosensitive drum 11 by the peeling claw 16 and conveyed to a fixing device 30 provided above the transfer roller 15. The residual toner remaining on the photosensitive drum 11 is removed from the surface of the photosensitive drum 11 by the cleaning member 17.

In the fixing device 30, the toner image on the recording sheet S is heat-fixed on the recording sheet S by heating and pressurizing the recording sheet S conveyed from the transfer nip Nt.
<Fixing device>
FIG. 2 is a schematic perspective view for explaining the internal configuration of the housing 30 a in the fixing device 30. In the fixing device 30, the recording sheet S passes through the housing 30a from the bottom to the top as shown in FIG. 1, but in FIG. 2, the traveling direction of the recording sheet S is indicated by an arrow D3. Thus, the orientation is changed so that the direction is perpendicular to the paper surface (from the front surface side to the back surface side).

  In the housing 30a of the fixing device 30 (see FIG. 1), as shown in FIG. 2, an endless heat generating belt 31 that can be rotated (circulated) and a pressure contacted to the outer peripheral surface of the heat generating belt 31 are provided. A pressure roller (pressing member) 32 and a fixing roller 33 disposed inside the circumferential movement area of the heat generating belt 31 are provided. The axes of the heat generating belt 31, the fixing roller 33, and the pressure roller 32 are parallel to each other.

FIG. 3 is a schematic cross-sectional view in the center in the axial direction of the heat generating belt 31, the fixing roller 33, and the pressure roller 32 in the fixing device 30, and FIG. It is a longitudinal cross-sectional view of one edge part of (width direction).
As shown in FIG. 3, the fixing roller 33 has a peripheral length of the outer peripheral surface shorter than a peripheral length of the inner peripheral surface of the heat generating belt 31, and a side plate 30 b (FIG. 4) constituting the housing 30 a of the fixing device 30. Reference) is supported rotatably. The pressure roller 32 is supported by the side plate 30b of the housing 30a in a state of being biased toward the fixing roller 33 by a biasing means (for example, a tension spring) (not shown).

A portion of the heat generating belt 31 in the circumferential direction is sandwiched between the fixing roller 33 and the pressure roller 32, and the recording sheet S is formed on the pressure contact portion between the outer peripheral surface of the heat generating belt 31 and the pressure roller 32. A fixing nip Nf through which the toner passes is formed.
The fixing roller 33 is depressed when the pressure roller 32 is pressed through the heat generating belt 31. The heat generating belt 31 is fixed in the fixing nip Nf where the pressure roller 32 is pressed. It will be in the state which became depressed like the outer peripheral surface which became depressed.

  The pressure roller 32 is rotated in a direction indicated by an arrow D <b> 2 when a rotational force of a drive motor (not shown) is transmitted. The heat generating belt 31 brought into a pressure contact state with the pressure roller 32 follows the rotation of the pressure roller 32 and rotates (circulates) in the direction indicated by the arrow D1. The fixing roller 33 follows the rotation of the heat generating belt 31 and rotates in the same direction as the heat generating belt 31 (the direction of the arrow D1).

When the recording sheet S that has passed through the transfer nip Nt reaches the fixing nip Nf, it passes through the fixing nip Nf by the pressure roller 32 and the heat generating belt 31 that rotate while being pressed against each other.
Since the heat generating belt 31 moves around in a state sandwiched between the fixing roller 33 and the pressure roller 32 at one place in the circumferential direction, it moves along the belt width direction (axial direction) during the circular movement (meandering). )there's a possibility that. For this purpose, as shown in FIGS. 2 and 4, the fixing device 30 is provided with a regulating member 34 that regulates the movement of the heat generating belt 31 beyond the allowable range in the width direction. Each restricting member 34 has the same configuration, and is disposed to face each end portion on both sides of the heat generating belt 31 in the axial direction. The configuration of each regulating member 34 will be described later.

  FIG. 5 is a longitudinal sectional view of the end portions on both sides of the heat generating belt 31 in the belt width direction. As shown in FIG. 5, the heat generating belt 31 has an insulating layer 31 a configured to have a cylindrical shape having a constant outer diameter over the entire circumference, and resistance heat is generated on the outer peripheral surface of the insulating layer 31 a. The layer 31b, the elastic layer 31c, and the release layer 31d are laminated in order. Moreover, the electroconductive power receiving member 31f comprised by the cylindrical shape is provided in the edge part of the both sides of the belt width direction in the heat generating belt 31, respectively. Each power receiving member 31f is formed in a cylindrical shape by a strip-shaped metal plate, for example.

  The insulating layer 31a has a thickness of about 5 to 100 μm. On the inner peripheral surface of each end portion on both sides in the axial direction, a stepped portion is formed with a constant thickness cut over the entire circumference. Yes. In each step portion of the insulating layer 31a, one end of the power receiving member 31f in the belt width direction (hereinafter, this end is referred to as a base end) is fitted, and the outer peripheral surface of the base end Is in close contact with the inner peripheral surface of each stepped portion of the insulating layer 31a. As a result, each power receiving member 31f is integrally supported by the insulating layer 31a in a coaxial state, and the other end (hereinafter, this end is referred to as a tip) extends from the insulating layer 31a in the belt width direction. It extends outward. The inner peripheral surface of each power receiving member 31f is located in the same plane as the inner peripheral surface of the insulating layer 31a.

The insulating layer 31a is made of a resin having excellent heat resistance and strength. In this embodiment, the insulating layer 31a is made of polyimide (PI) which is a heat resistant resin.
In addition, as resin which comprises the insulating layer 31a, not only PI (polyimide) but resin, such as PPS (polyphenylene sulfide) and PEEK (polyether ether ketone) excellent in heat resistance and intensity | strength, are also suitable.

In this embodiment, the resistance heating layer 31b laminated on the outer peripheral surface of the insulating layer 31a is configured by a resistance heating element in which a conductive filler is uniformly dispersed in PI of a heat resistant resin. The resistance heating layer 31b is laminated on the outer peripheral surface of the insulating layer 31a with a constant thickness over the entire circumference in the circumferential direction.
Although it does not specifically limit as a synthetic resin which comprises the resistance heating layer 31a, Since PI (polyimide) is excellent in heat resistance, it is preferable. PPS (polyphenylene sulfide), PEEK (polyether ether ketone), and the like are also suitable.

As the conductive filler, metals such as Ag, Cu, Al, Mg, and Ni, and carbon compounds such as graphite, carbon black, carbon nanofiber, and carbon nanotube are suitable.
The conductive filler is preferably fibrous. When the conductive filler is in a fibrous form, the probability that the conductive fillers are in contact with each other is higher if the conductive filler content is the same as compared with the case where the conductive filler is in a shape other than the fibrous form. . Thereby, the whole resistance heating layer 31a can be made into a uniform conductive state.

The electrical resistance of the resistance heating layer 31a changes as the thickness of the resistance heating layer 31a changes. For this reason, the electrical resistance can be adjusted by adjusting the thickness of the resistance heating layer 31a. The electric resistivity of the resistance heating layer 31a is preferably about 1.0 × 10 ^{−6 to} 9.9 × 10 ⁻³ Ω · m, and more preferably 1.0 × 10 ^{−5 to} 5.0 × 10 ⁻³ Ω. -About m is more preferable.

  Each end of the resistance heating layer 31b on both sides in the belt width direction protrudes toward the inner periphery over the entire circumference, covers each end face on both sides of the insulating layer 31a with a certain thickness, and protrudes respectively. The inner peripheral surface of the part is joined on the outer peripheral surface of each power receiving member 31f. As described above, the end portions on both sides in the axial direction of the resistance heating layer 31b are joined to the outer peripheral surface of the power receiving member 31f, so that the end portions on both sides in the axial direction of the resistance heating layer 31b and the power receiving members. 31f is in a conductive state.

The elastic layer 31c laminated on the outer peripheral surface of the resistance heating layer 31b uniformly transmits the heat generated from the resistance heating layer 31b to the toner image on the recording sheet S passing through the fixing nip Nf, and also the toner image. It is provided to apply a flexible pressure against.
Such an elastic layer 31c is preferably composed of a heat-resistant and elastic rubber material or a synthetic resin material, and heat-resistant elastomers such as silicone rubber and fluorine rubber are particularly suitable. In the present embodiment, the elastic layer 31c is made of silicone rubber having heat resistance and appropriate elasticity (flexibility), and is laminated on the resistance heating layer 31b with a thickness of about 0.1 to 20 mm. Has been.

Each end of the elastic layer 31c on both sides in the axial direction protrudes toward the inner periphery over the entire circumference, and covers each end face on both sides of the resistance heating layer 31b with a certain thickness. The inner peripheral surface of each protruding portion is in close contact with the outer peripheral surface of each power receiving member 31f.
As described above, each end portion of the resistance heating layer 31b is joined to each power receiving member 31f by being covered with each end portion of the elastic layer 31c in close contact with each power receiving member 31f. There is no possibility of peeling with respect to the member 31f, and the joining state of both is maintained.

In addition, the outer peripheral surface of each power receiving member 31f is not laminated (bonded) to the outer side (tip side) in the belt width direction from the portion where the elastic layer 31c is in close contact, and the resistance heating layer 31b, the elastic layer 31c, and the like. It is a non-joined part.
The release layer 31d laminated on the outer peripheral surface of the elastic layer 31c is provided so that the recording sheet S passing through the fixing nip Nf can be easily separated from the heat generating belt 31. The release layer 31d is made of fluorine tubes such as PFA (polytetrafluoroethylene), PTFE (polytetrafluoroethylene (tetrafluoroethylene) resin), ETFE (tetrafluoroethylene / ethylene copolymer resin), fluorine coating, etc. For example, it is comprised by the fixed thickness of about 5-100 micrometers.

Each power receiving member 31f provided on both sides of the insulating layer 31a is composed of a metal plate having excellent heat resistance and oxidation resistance. As the metal plate constituting each power receiving member 31f, nickel (Ni), stainless steel (SUS), aluminum (Al), copper (Cu), brass, phosphor bronze and the like are suitable.
The length along the axial direction of each power receiving member 31f is set to an appropriate value according to the diameter of the outer peripheral surface of the heat generating belt 31 (the diameter of the outer peripheral surface of the release layer 31d), but is usually 5 to 30 mm. Is set to about.

A contact member 36 is provided at the tip of each power receiving member 31f (tip of the non-joined portion). Each contact member 36 moves by a predetermined distance (maximum allowable distance) in a direction in which the heat generating belt 31 approaches each regulating member 34 provided on both sides of the belt width direction, respectively. It abuts on each regulating member 34.
Each contact member 36 is configured in a ring shape with a constant outer diameter by an elastic material such as resin or rubber, and is attached to the tip of each power receiving member 31f. On the inner peripheral surface of one end of each contact member 36 in the axial direction, a stepped portion is formed that is cut out with a constant thickness over the entire circumference, and the tip of the power receiving member 31f is formed in each stepped portion. Each part is fitted. The outer peripheral surface of the distal end portion of the power receiving member 31f fitted in the step portion is in close contact with the inner peripheral surface of the step portion. Thereby, each contact member 36 is integrally attached to each of the power receiving members 31f in a coaxial state.

  Each contact member 36 has a constant inner diameter equal to the inner diameter of the power receiving member 31f, except for the end portion on the power receiving member 31f side where the step portion is formed. An end portion (hereinafter referred to as a front end portion) opposite to the end portion on the power receiving member 31f side where the step portion is formed in each contact member 36 is in contact with the front end surface 36a of the power receiving member 31f over the entire circumference. The front end surface 36a of the power receiving member 31f is covered with the contact member 36. The front end surface of each contact member 36 faces each of the restriction members 34 and is a flat surface perpendicular to the axis of the contact member 36.

  In addition, the contact member 36 is not limited to a configuration in which the contact member 36 is formed of an elastic material and is attached to the distal end portion of the power receiving member 31f. For example, the contact member 36 may be formed by applying a liquid material such as a resin, which is used as the contact member 36, to a predetermined shape on the outer peripheral surface and the front end surface of the power receiving member 31 f and drying it. . In this case, the liquid material applied to the distal end portion of the power receiving member 31f is solidified, thereby having a predetermined elasticity and friction coefficient.

  A power feeding member 37a is pressed against the outer peripheral surface of the non-joined portion of each power receiving member 31f by a coil spring 37b, and the power receiving member 31f and the power feeding member 37a are in a conductive state. As shown in FIG. 2, the power supply member 37a is supplied with AC power from an AC power source 37c via a harness, and the AC current supplied to each power supply member 37a passes through the power receiving member 31f. To the resistance heating layer 31b. The resistance heating layer 31b is in a heat generating state when a current flows.

Each power supply member 37a is configured in the same shape by, for example, conductive brushes such as copper graphite and carbon graphite obtained by mixing and baking powders such as carbon powder and copper powder.
Each power supply member 37a is not limited to a configuration using such a conductive brush, and may be configured to use a conductive roller that rolls on the outer peripheral surface of each power reception member 31f.
Further, the contact load between each power supply member 37a and the power receiving member 31f is such that the power contact member 37a is slidably contacted with the power receiving member 31f even when the power receiving member 31f is deformed following the deformation of the heat generating belt 31. In order to maintain the state, the rotation speed of the heat generating belt 31 is set based on the material of the power feeding member 37a and the power receiving member 31f.

As shown in FIG. 3, the pressure roller 32 pressed against the outer peripheral surface of the heat generating belt 31 has an elastic layer 32b and a release layer 32c laminated in order on the outer peripheral surface of a pipe-shaped cored bar 32a. The diameter of the outer peripheral surface of the mold layer 32c (the outer diameter of the pressure roller 32) is about 20 to 100 mm.
The metal core 32a of the pressure roller 32 is formed of a metal pipe such as aluminum or iron having a thickness of about 1 to 10 mm. The elastic layer 32b of the pressure roller 32 is configured to have a thickness of about 1 to 20 mm by a highly heat-resistant elastic body such as silicone rubber or fluororubber.

  The release layer 32c provided on the outermost peripheral portion of the pressure roller 32 has release properties with respect to the recording sheet S, and includes PFA (polytetrafluoroethylene) and PTFE (polytetrafluoroethylene (tetrafluoride)). Resin), ETFE (tetrafluoroethylene / ethylene copolymer resin) and other fluorine-based tubes, fluorine-based coatings, and the like, for example, are formed to a thickness of about 5 to 100 μm. Note that the release layer 32c may be either conductive or insulating.

As shown in FIG. 3, the fixing roller 33 provided in the circumferential movement region of the heat generating belt 31 includes a cored bar 33 b provided in the shaft center part and a cylindrical shape laminated on the outer peripheral surface of the cored bar 33 b over the entire circumference. The roller main body 33a.
The cored bar 33b of the fixing roller 33 is constituted by a metal pipe made of aluminum, iron or the like having a thickness of about 1.0 to 10 mm. The roller body 33a is made of an elastic material having excellent heat resistance such as silicone rubber and fluororubber.

The roller main body 33a of the fixing roller 33 has elasticity, and as shown in FIG. 3, the pressure roller 32 is pressed through the heat generating belt 31 to be depressed in a concave shape.
Note that when the recording sheet S passes through the fixing nip Nf formed at the pressure contact portion between the heat generating belt 31 and the pressure roller 32, the elastic layer 31c of the heat generating belt 31 is further deformed. Thereby, stress due to deformation of the elastic layer 31c is applied to the resistance heating layer 31b.

The insulating layer 31a on which the resistance heating layer 31b is laminated is configured to deform together with the resistance heating layer 31b following the deformation of the elastic layer 31c when such a stress is applied to the resistance heating layer 31b. . Each power receiving member 31f provided at each end on both sides of the insulating layer 31a is rigid so as not to hinder such deformation of the insulating layer 31a.
Since each power receiving member 31f has higher rigidity as it becomes thicker, damage such as breakage is less likely to occur, but is less likely to be deformed due to higher rigidity. Therefore, each power receiving member 31f preferably has a thickness of about 10 to 100 μm and a thickness of about 30 to 80 μm so as not to hinder the deformation of the resistance heating layer 31b and the insulating layer 31a due to the deformation of the elastic layer 31c. More preferable.

  The heat generating belt 31 having such a configuration includes, for example, an insulating layer 31a, a pair of power receiving members 31f formed by electroforming, spatula drawing, press drawing, etc. and set on a metal core. It can be manufactured by laminating the resistance heating layer 31b and the like. Each power receiving member 31f may be formed by forming a belt-like metal sheet into a cylindrical shape by laser welding or the like. Thus, by forming the power receiving member 31f in a cylindrical shape in advance, the base end portion of the power receiving member 31f can be easily laminated with the insulating layer 31a, and can be manufactured efficiently.

Moreover, in order to improve the adhesiveness between the power receiving member 31f and the insulating layer 31a, a hole may be provided in the stacked portion of the power receiving member 31f with the insulating layer 31a by etching, laser drilling, or the like.
While the recording sheet S conveyed to the fixing nip Nf passes through the fixing nip Nf formed by the pressure contact between the heat generating belt 31 and the pressure roller 32, the unfixed toner image on the recording sheet S is pressurized. At the same time, the heat generating belt 31 is heated by the heat generating belt 31. As a result, the unfixed toner image on the recording sheet S is melted and pressed and fixed on the recording sheet S.

As shown in FIG. 1, the recording sheet S that has passed through the fixing nip Nf is separated from the heat generating belt 31 by the separation claw 35 and discharged onto the paper discharge tray 19 by the paper discharge roller pair 24.
As shown in FIGS. 2 and 4, the regulating member 34 that regulates the movement of the heat generating belt 31 in the width direction is formed in a ring shape in which the tip of the power receiving member 31 f in the heat generating belt 31 is fitted. The three support members 39 provided on the side plate 30b of the housing 30a are rotatably supported.

  As shown in FIG. 4, each regulating member 34 has a short axial length, a cylindrical portion 34a having an inner diameter slightly larger than the outer diameter of the power receiving member 31f, and a cylindrical shape so as to face the tip portion of the power receiving member 31f. And a regulating surface 34b provided on the inner peripheral side portion of the edge adjacent to the side plate 30b of the housing 30a in the portion 34a. The restricting member 34 is formed of, for example, a metal plate.

A through hole 34c is formed concentrically at the center of the restricting surface 34b, and an inner peripheral portion around the through hole 34c protrudes in a direction approaching the side plate 30b. An outer peripheral side portion that is continuous with the cylindrical portion 34a in the regulation surface 34b is a flat surface parallel to the side plate 30b.
A cored bar 33b of the fixing roller 33 provided inside the heat generating belt 31 passes through a through hole 34c provided in the regulating surface 34b of the regulating member 34, and each end of the cored bar 33b is connected to the housing 30a. The side plate 30b is rotatably supported by a bearing 30c.

The three support members 39 that rotatably support the regulating member 34 are provided such that one support member 39 is provided at a position 180 degrees apart from the fixing nip Nf in the circumferential direction, and the other two support members Nos. 39 are provided on both sides in the circumferential direction with respect to the fixing nip Nf and separated from the fixing nip Nf by an equal distance.
Each support member 39 includes a support shaft 39a attached perpendicularly to the side plate 30b, and a bearing 39b rotatably attached to a distal end portion of the support shaft 39a located in the housing 30a.

As shown in FIG. 2, on the outer circumferential surface of each bearing 39b (outer circumferential surface of the outer ring), a flange portion 39c that regulates the movement of the regulating member 34 in the direction approaching the side plate 30b of the housing 30a is provided on the side plate 30b. It is provided in the edge part close to.
Each restricting member 34 is supported by three support members 39 in a state in which the restricting surface 34b is parallel to the side plate 30b and in a state where movement in the direction approaching the side plate 30b of the housing 30a is restricted. . In this case, since the outer peripheral surface of the cylindrical portion 34a is supported in a line contact state with the outer peripheral surface of the bearing 39b in each support member 39 at three locations in the circumferential direction, the restricting member 34 is restricted. Can be rotated by applying a relatively small rotational force.

  In a state where each of the restricting members 34 is in contact with the flange portions 39c of the respective bearings 39b of the three support members 39, the heat generating belt 31 positioned between the restricting members 34 has a maximum allowable range in the width direction. Be movable across values. Therefore, when the heated heat generating belt 31 moves in the direction approaching one of the regulating members 34 over the maximum distance of the allowable range, the heating belt 31 is provided at the distal end portion of the power receiving member 31f facing the regulating surface 34b. The abutting member 36 abuts on the regulating surface 34 b of the regulating member 34. As a result, the heat generating belt 31 is restricted from moving in the belt width direction beyond the allowable range.

  Moreover, the friction coefficient of the front end surface 36a of each contact member 36 with respect to the regulation surface 34b of the regulation member 34 is larger than the friction coefficient of the front end surface of the power receiving member 31f. As a result, when the heat generating belt 31 is rotated and the front end surface of the abutting member 36 abuts on the regulating surface 34b of the regulating member 34 that is supported by the three supporting members 39 in the rotation stopped state, A large frictional force acts.

In this case, when the frictional force acting between the two is smaller than the static frictional force, the front end surface of the abutting member 36 is opposed to the regulating surface 34b of the regulating member 34 in the rotation stopped state. When it slides and becomes larger than the static frictional force, the regulating member 34 rotates together with the contact member 36.
In the fixing device 30 having such a configuration, when a current is supplied to one power supply member 37a, a current is supplied from the one power receiving member 31f that is in sliding contact with the power supply member 37a to the resistance heating layer 31b. The current supplied to the resistance heating layer 31b flows in the resistance heating layer 31b along the belt width direction, and flows from the other power receiving member 31f to the power feeding member 37a that is in sliding contact with the power receiving member 31f. In this way, when the current flows through the resistance heating layer 31b, the resistance heating layer 31b generates heat.

  The heat generated in the insulating layer 31a is transmitted to the release layer 31d through the resistance heating layer 31b and the elastic layer 31c. The heat transferred to the release layer 31d is transferred to the recording sheet S that passes through the fixing nip Nf. As a result, the toner image on the recording sheet S is melted. The toner image in a molten state is fixed onto the recording sheet S by being pressed onto the recording sheet S by the pressure roller 32.

  Note that the electrical resistivity of the resistance heating layer 31b includes the power supplied to the resistance heating layer 31b, the applied voltage, the thickness of the resistance heating layer 31b, the outer diameter and the circumferential length of the heating belt 31, and the fixing roller 33. Is set on the basis of the diameter and the axial length thereof. For example, resistance heat generation in the heat generating belt 31 in which the outer diameter and the circumferential length are set by setting the outer diameter and the circumferential length of the heat generating belt 31 depending on the fixing property, durability, and the like of the toner image on the recording sheet S. The thickness, electric resistivity, and the like of the resistance heating layer 31b are set so that a predetermined heat generation amount can be obtained by the layer 31b.

During such a fixing operation, each power reception is caused by fluctuations in pressure applied to the heat generating belt 31 when the recording sheet passes through the fixing nip Nf, vibrations of a gear that transmits a rotational force for rotating the heat generating belt 31, and the like. Each of the power supply members 37a that are in sliding contact with the member 31f is separated from the power receiving member 31f, and there is a possibility that a spark is generated between them.
In this case, since the power feeding member 37a is in a sliding contact state at the non-joined portion where the resistance heating layer 31b of the power receiving member 31f is not laminated, the high heat generated by the occurrence of the spark is directly applied to the resistance heating layer 31b. I ca n’t tell you. Therefore, there is no possibility that the resistance heating layer 31b is thermally expanded and damaged by the heat of the spark.

  Further, when the heat generating belt 31 meanders during rotation of the heat generating belt 31, the heat generating belt 31 moves in a direction approaching one of the regulating members 34, and when the heat generating belt 31 moves over the maximum distance of the allowable range, The abutting member 36 facing the regulating member 34 abuts on the regulating surface 34 b of the regulating member 34. In this case, since the heat generating belt 31 circulates in a meandering state, the contact member 36 normally contacts the restriction surface 34b at one place in the circumferential direction.

When the contact member 36 contacts the restriction surface 34b, the contact member 36 has elasticity, so that an impact generated between the contact member 36 and the restriction surface 34b is reduced.
In addition, when the contact member 36 rotates integrally with the power receiving member 31f of the heat generating belt 31 and one place in the circumferential direction on the front end surface of the contact member 36 contacts the restriction surface 34b, A frictional force is generated at the contact portion between the front end surface of the contact member 36 and the regulating surface 34b.

When this frictional force is smaller than the static frictional force, the restricting member 34 maintains the stopped state without rotating. Thereby, the front end surface of the contact member 36 is in a sliding state with respect to the regulating surface 34b of the regulating member 34 in the rotation stopped state, and a sliding frictional force is generated in both sliding portions.
This sliding frictional force is transmitted as a reaction force acting on the tip of the power receiving member 31f via the contact member 36 in the direction opposite to the rotational direction. In this case, since the contact member 36 is laminated on the outer peripheral surface of the power receiving member 31f in a state of covering the distal end surface of the power receiving member 31f, the thickness of the contact member 36 (radial direction) Is longer than the thickness of the power receiving member 31f. Therefore, the contact area of the contact portion of the contact member 36 with the regulation surface 34b is wider than when the tip surface of the power receiving member 31f directly contacts the regulation surface 34b.

  From this, the sliding frictional force (reaction force) acting on the contact member 36 acts on the tip surface of the contact member 36 having a large area and is dispersed in the contact member 36. Accordingly, the tip of the power receiving member 31f acts in a state where the sliding frictional force (reaction force) is reduced. Since the reaction force acting on the tip of the power receiving member 31f becomes a pulling force along the circumferential direction, the tip force of the power receiving member 31f is directly applied to the regulating surface 34b. This is reduced as compared with the case of contact.

  Thus, while the regulating surface 34b of the regulating member 34 and the tip surface of the abutting member 36 slide, the frictional force between the tip surface of the abutting member 36 and the regulating surface 34b of the regulating member 34 is When it becomes larger than the static frictional force, the restricting member 34 rotates integrally with the contact member 36 in the rotating state. As a result, no frictional force is generated between the regulating member 34 and the contact member 36, and no reaction force from the regulating member 34 acts on the tip of the power receiving member 31f. A force in the direction opposite to the rotation direction does not act on the tip.

  In this case, the friction coefficient between the regulation surface 34b of the regulation member 34 and the distal surface of the contact member 36 is large because the friction coefficient of the regulation surface 34b with respect to the regulation surface 34b of the regulation member 34 is large. In a relatively short time, it becomes greater than the static frictional force, and the regulating member 34 quickly rotates together with the contact member 36. Therefore, the time for the contact member 36 to slide relative to the regulating member 34 is shortened.

  From the above, when the heat generating belt 31 comes into contact with the regulating member 34, it acts on the tip of the power receiving member 31f in a state where the pulling force along the circumferential direction is reduced and only for a short time. do not do. For this reason, even if the contact between the contact member 36 and the regulating member 34 is repeated, there is no possibility that the power receiving member 31f will crack in a short period of time. In particular, since the distal end portion of the power receiving member 31f is a non-joined portion to which the resistance heating layer 31b or the like is not joined, the tensile strength is relatively small. There is no risk of cracking. As a result, the fixing device can be used stably over a long period of time.

  In the state where the contact member 36 is not in contact, the restriction member 34 is supported by the three support bodies 39 in a rotation stop state with a relatively small frictional force. In this case, it is easily rotated by a relatively small rotational force transmitted from the contact member 36. As a result, the time from when the abutting member 36 abuts to when the regulating member 34 rotates is further shortened. Therefore, the sliding frictional force between the abutting member 36 and the regulating member 34 causes the tip of the power receiving member 31f to move. The time during which the force in the direction opposite to the rotation direction is applied can be further shortened.

As described above, the contact member 36 is not limited to a configuration in which the contact member 36 is formed in a ring shape having a constant thickness (radial length) over the entire circumference.
FIG. 6 is an end view showing the distal end surface of the contact member 36 in a state in which the contact member 36 according to the modification is provided at the distal end portion of the power receiving member 31f in the present embodiment. In the contact member 36 shown in FIG. 6, incisions 36 d from the outer peripheral surface are formed along the axial direction at four positions spaced apart in the circumferential direction.

In this case, each notch 36d is formed over the entire length in the axial direction of the contact member 36 outside the outer peripheral surface of the power receiving member 31f, and the front end surface of the power receiving member 31f is formed by the contact member 36 over the entire periphery. It is in a covered state.
In such a configuration of the abutting member 36, the notch 36d is formed in the abutting member 36 from the outer peripheral surface, so that when the recording sheet S passes through the fixing nip Nf, power is received by the stress applied to the insulating layer 31a. Even if the member 31f is deformed, the contact member 36 can be deformed following the deformation of the power receiving member 31f. Therefore, when the stress due to the deformation of the power receiving member 31f is applied to the contact member 36, the reaction force from the contact member 36 can be reduced.

Note that the number of the notches 36d is not particularly limited, and may be formed at least at one place in the circumferential direction. Thereby, the reaction force applied to the power receiving member 31f from the contact member 36 can be reduced.
Further, the contact member 36 does not have to be continuous in the circumferential direction on the outer peripheral surface of the power receiving member 31f. For example, as shown in FIG. 7, the contact member 36 is divided into three stacked portions 36e. It may be a configuration. In this case, the stacked portions 36e are arranged at a certain interval in the circumferential direction. With such a configuration, the reaction force applied from the contact member 36 to the power receiving member 31f can be further reduced by the deformation of the power receiving member 31f. Note that the contact member 36 is not limited to the configuration in which the laminated portion 36e is provided in three places in the circumferential direction, and may be provided in two or more places.

  Further, as described above, the contact member 36 provided at the distal end portion of each power receiving member 31f does not need to be configured to cover the distal end surface of the power receiving member 31f. FIG. 8 is a longitudinal sectional view of the end portion of the heat generating belt 31 when the contact member 36 does not cover the front end surface of the power receiving member 31f, and FIG. 9 is provided with the contact member 36 shown in FIG. It is an end view which shows the front end surface in the power receiving member 31f.

As shown in FIGS. 8 and 9, the contact member 36 is laminated on the outer peripheral surface of the distal end portion of the power receiving member 31f with a constant thickness over the entire circumference, and the power receiving member 31f located on the regulating member 34 side. The front end surface is not covered by the contact member 36 and is located in the same plane as the front end surface of the power receiving member 31f.
Also in this case, the friction coefficient of the front end surface of the contact member 36 with respect to the regulation surface 34b of the regulation member 34 is larger than the friction coefficient of the front end surface of the power receiving member 31f.

Even in such a configuration, when the heat generating belt 31 rotates and the heat generating belt 31 moves over the maximum distance in the allowable range in a direction approaching any one of the restricting members 34, the contact member 36 that faces the restricting member 34. In addition, the front end surface of the power receiving member 31 f comes into contact with the regulation surface 34 b of the regulation member 34.
Also in this case, the sliding frictional force acts as a reaction force on the contact member 36 and the power receiving member 31f by sliding the tip surfaces of the contact member 36 and the power receiving member 31f with respect to the regulating member 34. However, since the reaction force acts not only on the front end surface of the power receiving member 31 f but also on the contact member 36, the reaction force is dispersed by the contact member 36.

Thereby, the reaction force acting on the tip of the power receiving member 31f is reduced as compared with the case where the contact member 36 is not provided, and the pulling force along the circumferential direction acting on the tip of the power receiving member 31f is reduced. Will be.
Further, since the friction coefficient between the front end surface of the contact member 36 and the restriction surface 34b of the restriction member 34 is large, the restriction surface 34b of the restriction member 34 and the front end surface of the contact member 36 are in contact with each other. When they come into contact with each other, the frictional force between them becomes larger than the static frictional force in a relatively short time, and the regulating member 34 rotates together with the contact member 36. Thereby, the time for the reaction force to act on the tip of the power receiving member 31f is shortened.

  From the above, also in the configuration shown in FIGS. 8 and 9, when the heat generating belt 31 is in contact with the regulating member 34, the reduced tensile force acts on the front end portion of the power receiving member 31 f for a short time. For this reason, even if the contact between the contact member 36 and the regulating member 34 is repeated, there is no possibility that the power receiving member 31f will crack in a short period of time. As a result, the fixing device can be used stably over a long period of time.

In the case of the configuration shown in FIGS. 8 and 9, the contact member 36 does not need to be made of an elastic material, and the friction coefficient at the distal end surface of the contact member 36 in the rotated state is restricted. It is sufficient that the regulating member 34 is set so as to be able to quickly rotate integrally with the abutting member 36 by abutting the flat surface of the surface 34b.
Further, in the contact member 36 shown in FIGS. 8 and 9, a plurality of cuts 36d along the axial direction may be formed on the outer peripheral surface of the contact member 36 at regular intervals in the circumferential direction. . Further, the contact member 36 may be provided with a plurality of laminated portions 36e divided in the circumferential direction.

In any case, the contact member 36 is formed by laminating the contact member 36f on the outer peripheral surface of the distal end portion of the power receiving member 31f in a bonded state, and a liquid material such as a resin used as the contact member 36 in the circumferential direction. Any of the structures formed by applying a predetermined thickness to the predetermined position and drying it may be used.
In the present embodiment, the portion of the contact member 36 provided on the outer peripheral surface of the distal end portion of the power receiving member 31f may be stacked on the inner peripheral surface of the distal end portion of the power receiving member 31f. Also in this case, the contact member 36 is configured so as to be in contact with the flat surface of the restricting surface 34b of the restricting member 34 when the heat generating belt 31 moves in the width direction over the maximum allowable distance. The

  Further, in the present embodiment, the regulating member 34 does not need to be configured to rotate integrally with the regulating member 34 by the contact of the abutting member 36. It is good also as the fixed state which does not rotate even if it touches. In this case, while the contact member 36 is in contact with the restriction member 34, the sliding friction force generated between the restriction member 34 and the contact member 36 continues to act on the contact member 36 as a reaction force. For this reason, this reaction force continues to be applied to the tip of the power receiving member 31f.

  However, in this case as well, since the sliding frictional force (reaction force) is dispersed by the contact member 36 and acts on the distal end portion of the power receiving member 31f, the circumferential direction generated at the distal end portion of the power receiving member 31f is also observed. The pulling force is reduced. Therefore, even if the contact between the contact member 36 and the regulating member 34 is repeated, it is possible to prevent the power receiving member 31f from cracking over a relatively long period.

  In the configuration in which the regulating member 34 is in a fixed state that does not rotate, when the contact member 36 comes into contact with the regulating member 34, the sliding frictional force with the regulating member 34 acts on the contacting member 36 as a reaction force. Therefore, the friction coefficient with the regulating member 34 is configured to be low so that the sliding frictional force with the regulating member 34 is reduced. Thereby, the pulling force along the circumferential direction which generate | occur | produces in the front-end | tip part of the electric power receiving member 31f can be reduced.

[Embodiment 2]
FIG. 10 is a longitudinal cross-sectional view of one regulating member 34 and the end portion of the heat generating belt 31 in this embodiment, and FIG. 11 is an end view showing the end surface of the restricting member 34 on the heat generating belt 31 side.
In the first embodiment, the contact member 36 is provided at the distal end portion of the power receiving member 31f. However, in the present embodiment, as illustrated in FIG. 10, the contact member 36 is disposed at the distal end portion of the power receiving member 31f. The contact member 38 that contacts the front end of the power receiving member 31f is provided on the regulating member 34 without providing the control member 34.

  As shown in FIG. 11, the contact member 38 has a ring shape that is continuous over the entire circumference, and the cylindrical portion 34 a of the regulating member 34 can be brought into contact with the tip of the power receiving member 31 f that is in a rotating state. Is provided inside. The contact member 38 is integrally attached to the regulating member 34 in a state in which the contact member 38 is in contact with the inner circumferential surface of the cylindrical portion 34a and the regulating surface 34b over the entire circumference.

The contact member 38 is formed of an elastic body, and is inclined so as to be sequentially away from the heat generating belt 31 as the end surface 38c on the heat generating belt 31 side becomes the center side of the regulating member 34.
When the heat generating belt 31 in the rotated state moves in the direction approaching each regulating member 34 over the maximum allowable distance, the tip of the power receiving member 31f comes into contact with the inclined end surface 38c of the contact member 38.

  The contact member 38 has elasticity (flexibility) such that when the distal end portion of the power receiving member 31f comes into contact with the end surface 38c of the contact member 38, the distal end portion of the power receiving member 31f enters into the contact member 38. ing. When the distal end portion of the power receiving member 31f is in a state of being bitten into the contact member 38, the contact member 38 is in contact with the outer peripheral surface and the inner peripheral surface at the distal end portion of the power receiving member 31f, and the contact member 38 and the power receiving member 31f The contact area increases with respect to the case where only the front end surface of the power receiving member 31 f is in contact with the contact member 38.

Further, when the tip of the power receiving member 31f is in the contact member 38, the contact member 38 is rotated with the power receiving member 31f by a frictional force with the power receiving member 31f. The coefficient of friction is set.
Other configurations are the same as those of the first embodiment.
Also in the present embodiment, when the heat generating belt 31 in the rotating state moves over the maximum distance in the allowable range in the direction approaching each regulating member 34, the inclined end surface 38 c of the contact member 38 provided on the regulating member 34. Then, the tip of the power receiving member 31 f hits and enters the contact member 38.

  In this case, since the contact member 38 is made of an elastic body having flexibility, the impact when the distal end portion of the power receiving member 31f contacts the contact member 38 is reduced. In addition, since the end face 38c of the contact member 38 is inclined with respect to the tip end of the power receiving member 31f, the end face of the power receiving member 31f is more abutted than when the end face is perpendicular to the axis. The reaction force applied along the axial direction from the contact member 38 at the time of contact can be reduced.

When the front end portion of the power receiving member 31f is in a state of being bitten into the contact member 38, the contact area between the front end portion of the power receiving member 31f and the contact member 38 increases, and the frictional force between the power receiving member 31f and the contact member 38 is Further, it is larger than the case where the front end portion of the power receiving member 31f and the regulating surface 34b of the regulating member 34 are in direct contact with each other.
As a result, the frictional force between the front end of the power receiving member 31f and the regulating surface 34b of the regulating member 34 becomes larger than the static frictional force in a relatively short time, and the contact member 38 provided on the regulating member 34 in the rotation stopped state. When the force in the rotational direction increases from the power receiving member 31f, the power receiving member 31f moves quickly and integrally. Thereby, the regulating member 34 to which the contact member 38 is attached rotates together with the power receiving member 31f.

  As described above, when the power receiving member 31f comes into contact with the contact member 38, the regulating member 34 rotates rapidly, so that the rotating power receiving member 31f hardly slides against the rotation stopped contact member 38. Therefore, the pulling force in the direction opposite to the rotational direction acts on the power receiving member 31f due to the sliding resistance with the contact member 38. Thereby, even if contact with power receiving member 31f and contact member 38 is repeated, there is no possibility that a crack will occur in power receiving member 31f in a short period of time.

  In this case as well, the regulating member 34 is supported by the three support members 39 in a rotationally stopped state with a relatively small frictional force when the power receiving member 31f is not in contact with the power receiving member 31f. A relatively large frictional force is applied to the regulating member 34 in contact with the member 38, so that the rotation is started with the power receiving member 31f very quickly. Also by this, it can suppress that tensile force acts on the front-end | tip part of the power receiving member 31f.

Also in this embodiment, the contact member 38 provided on the regulating member 34 is not limited to the ring-shaped configuration having a constant thickness (radial length) over the entire circumference as described above.
FIG. 12 is an end view showing an end face on the heat generating belt 31 side of the regulating member 34 provided with the contact member 38 according to the modification in the present embodiment. As shown in FIG. 12, in the outer peripheral portion of the contact member 38, incisions 38 d from the outer peripheral surface are provided along the axial direction of the contact member 38 at four positions spaced apart in the circumferential direction. Is formed.

  As described above, the notch 38 d is formed in the outer peripheral side portion of the contact member 38, so that the end portion of the power receiving member 31 f comes into contact with the contact member 38, and the regulating member 34 rotates integrally with the heat generating belt 31. In this state, when the recording sheet S passes through the fixing nip Nf and the power receiving member 31f is deformed, a large reaction force from the contact member 38 is suppressed from being applied to the power receiving member 31f.

  Further, the contact member 38 does not need to be formed in a ring shape that is continuous in the circumferential direction, and as shown in FIG. 13, the three contact members divided in the circumferential direction inside the cylindrical portion 34 a of the regulating member 34. 38 may be used. Even in such a configuration, even if the power receiving member 31f is deformed when the recording sheet S passes through the fixing nip Nf with the regulating member 34 rotating integrally with the heat generating belt 31, the contact member 38 is not deformed. By deforming following the deformation of the power receiving member 31f, it is possible to further suppress the application of a large reaction force from the contact member 38 to the power receiving member 31f. In addition, the contact member 38 is not restricted to the structure divided into three in the circumferential direction, What is necessary is just to be divided into two or more in the circumferential direction.

  Further, the contact member 38 provided in the regulating member 34 is not limited to the configuration in which the tip end portion of the power receiving member 31f bites in as the heat generating belt 31 moves in the belt width direction. For example, a cylindrical contact member 38 having a constant inner diameter may be provided at a predetermined position on the regulation surface 34 b of the regulation member 34. In this case, when the heat generating belt 31 moves in the belt width direction, the front end portion of the power receiving member 31f is inserted into the contact member 38, and the inner peripheral surface of the contact member 38 becomes the outer peripheral surface of the front end portion of the power receiving member 31f. The contact member 38 is provided on the regulation surface 34b of the regulation member 34 so as to be in contact.

In this case, when the distal end surface of the power receiving member 31f inserted into the contact member 38 comes into contact with the regulating surface 34b of the regulating member 34, the inner circumferential surface of the contact member 38 and the outer circumference of the distal end portion of the power receiving member 31f. Since the surface is in contact, the contact area between the contact member 38 and the power receiving member 31f increases as compared with the case where the contact member 38 is not provided.
Further, a cylindrical contact member 38 having a constant outer diameter may be provided at a predetermined position on the regulation surface 34 b of the regulation member 34. In this case, when the heat generating belt 31 moves in the width direction, the contact member 38 is inserted into the distal end portion of the power receiving member 31f, and the outer peripheral surface of the contact member 38 is the inner periphery of the distal end portion of the power receiving member 31f. A contact member 38 is provided on the regulation surface 34b of the regulation member 34 so as to be in contact with the surface.

Also in this case, when the distal end surface of the power receiving member 31f inserted into the contact member 38 comes into contact with the regulating surface 34b of the regulating member 34, the outer circumferential surface of the contact member 38 and the inner circumference of the distal end portion of the power receiving member 31f. Since the surface is in contact, the contact area between the contact member 38 and the power receiving member 31f increases as compared with the case where the contact member 38 is not provided.
[Modification]
In the above embodiment, the base end portions of the pair of power receiving members 31f are joined to the end portions of the resistance heating layer 31b stacked on the insulating layer 31a in a state where the base end portions are fitted to the end portions of the insulating layer 31a. However, the present invention is not limited to this configuration, and the base end portions of the pair of power receiving members 31f may be directly fitted and joined to the respective end portions of the resistance heating layer 31b.

Further, the power supply member 37a is configured to be in sliding contact with the outer peripheral surface of the power receiving member 31f. However, the configuration is not limited thereto, and the power supply member 37a may be configured to be in sliding contact with the inner peripheral surface of the power receiving member 31f.
Further, although the commercial AC power source is used as the power source of the fixing device 30, a DC power source may be used.

  In the above embodiment, the pressure roller 32 is rotationally driven. However, instead of such a configuration, the fixing roller 33 is rotationally driven, and the heat generating belt 31 and the pressure roller 32 are fixed. It is good also as a structure made to follow the rotation of the roller 33 and to rotate. Alternatively, as a configuration in which both the pressure roller 32 and the fixing roller 33 are rotationally driven, the heat generating belt 31 may be configured to follow both the pressure roller 32 and the fixing roller 33 and rotate.

  Further, the fixing roller nip Nf is formed by press-contacting the pressure roller 32 to the heat generating belt 31 or the fixing roller 33. However, the present invention is not limited to such a configuration, and as a pressing means for forming the fixing nip Nf. A pressure belt may be used. Further, the fixing nip Nf may be formed by using a pressure member or the like that is fixedly provided, instead of the pressure means that rotates such as the pressure roller 32 and the pressure belt.

  Furthermore, the image forming apparatus according to the present invention is not limited to a printer that forms a monochrome image, and may be a color printer. Furthermore, the present invention is not limited to a printer, and can also be applied to a copying machine, an MFP (Multiple Function Peripheral), a FAX, and the like (in either case, either a color image or a monochrome image).

  In the present invention, in a configuration that can prevent the resistance heating layer from being damaged by the spark generated between the power receiving member and the power feeding member, the power receiving member is prevented from being damaged, and the heating belt is moved beyond the allowable range in the width direction. It is useful as a technology that can be regulated.

DESCRIPTION OF SYMBOLS 30 Fixing device 31 Heat generating belt 31a Insulating layer 31b Resistance heat generating layer 31c Elastic layer 31d Release layer 31f Power receiving member 32 Pressure roller 33 Fixing roller 34 Control member 36 Contact member 37a Power supply member 37c AC power supply 38 Contact member

Claims (5)

A pressure member is pressed on the outer peripheral surface of an endless heat generating belt having a resistance heat generating layer to form a fixing nip, and the unfixed image is heated while the sheet on which the unfixed image is formed passes through the fixing nip. A fixing device for fixing;
Cylindrical power receiving members respectively disposed on both sides of the heat generating belt in the belt width direction, wherein one end of each power receiving member is electrically connected to each end on both sides of the resistance heat generating layer in the belt width direction. A pair of power receiving members that are joined in a state and the other end is located on both outer sides of the resistance heating layer;
A pair of power supply members in sliding contact with the outer peripheral surface or inner peripheral surface of the other end of each power receiving member;
A pair of restricting members disposed to face the other end of each power receiving member in order to restrict movement of the heat generating belt in the belt width direction;
When the rotating heat generating belt moves in the belt width direction, one or both of the outer peripheral surface and the inner peripheral surface of the other end of the power receiving member from the front end surface of the other end of the power receiving member A contact member provided on the regulating member so as to come into contact with
I have a,
The contact member has a continuous ring shape along the circumferential direction of the power receiving member,
The fixing device according to claim 1, wherein the contact member is provided with a cut from the outer peripheral surface along at least one portion in the circumferential direction along the axial direction . A pressure member is pressed on the outer peripheral surface of an endless heat generating belt having a resistance heat generating layer to form a fixing nip, and the unfixed image is heated while the sheet on which the unfixed image is formed passes through the fixing nip. A fixing device for fixing;
Cylindrical power receiving members respectively disposed on both sides of the heat generating belt in the belt width direction, wherein one end of each power receiving member is electrically connected to each end on both sides of the resistance heat generating layer in the belt width direction. A pair of power receiving members that are joined in a state and the other end is located on both outer sides of the resistance heating layer;
A pair of power supply members in sliding contact with the outer peripheral surface or inner peripheral surface of the other end of each power receiving member;
A pair of restricting members disposed to face the other end of each power receiving member in order to restrict movement of the heat generating belt in the belt width direction;
When the rotating heat generating belt moves in the belt width direction, one or both of the outer peripheral surface and the inner peripheral surface of the other end of the power receiving member from the front end surface of the other end of the power receiving member A contact member provided on the regulating member so as to come into contact with
I have a,
The fixing device according to claim 1, wherein a plurality of the contact members are provided at intervals in a circumferential direction of the power receiving member . 3. The fixing device according to claim 1, wherein the contact member is formed of an elastic body that is in a state where the other end portion of the power receiving member is in contact with the contact member. 4. The fixing device according to claim 3 , wherein a surface of the contact member that faces the other end of the power receiving member is inclined with respect to a belt width direction of the heat generating belt. An image forming apparatus, comprising a fixing device according to any one of claims 1-4.

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