JPH11202663A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make electrical connection between electrode members constituting a sliding contact point mechanism in an more excellent connecting state than heretofore at a fixing device supplying a heating element fixed to a roller with electric power through the sliding contact point mechanism. SOLUTION: A rotary electrode member 71 possesses a contact surface nearly orthogonal with the rotary axial line of a heating roller 10, and a stationary electrode member 72 is brought into contact with the contact surface. The stationary electrode member 72 is brought into press-contact with the rotary electrode member 71 by plural conductive protrusions 78 which are in a pressed state by one feeding plate 77. Even if defective contact is caused by a certain conductive protrusion 78, an electrically connected state is maintained by remaining conductive protrusions 78, so that the electrical connection between the electrode members is made into the more excellent connecting state than heretofore. Also, the stationary electrode member 72 is brought into contact with the vicinity of the center of rotation of the rotary electrode member 71 within the contact surface, so that the wear of a contact point and vibration and noise caused at the contact point are suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for fixing an image on a recording medium by forming an image on the recording medium with a heat-fusible recording material and then heating the recording medium.

[0002]

2. Description of the Related Art Conventionally, some apparatuses (hereinafter, referred to as image forming apparatuses) having an image forming mechanism capable of forming an image on a recording medium, such as a copying machine, a printer, and a facsimile machine, include an image forming apparatus. As a recording material, there is a type using a heat-fusible recording material. This type of image forming apparatus generally fixes a recording material on a recording medium by melting or softening the recording material by heating the recording medium with a fixing device after attaching the recording material to the recording medium. I have.
More specifically, for example, an electrophotographic image forming apparatus, such as a laser printer, forms an image on a recording medium using a toner that is a heat-fusible recording material, and then forms the image. By heating the recording medium with the fixing device,
The toner is melted or softened and fixed on the recording medium.

As a fixing device provided in such an image forming apparatus, as described in JP-A-8-314309, a sheet-like heating element is fixed to the inner peripheral surface of a metal tube and heated. A roller has been proposed which heats a recording medium with heat from a heating roller while sandwiching the recording medium between the heating roller and the pressure roller. In this fixing device, electric power is supplied to the sheet-shaped heating element that is driven to rotate together with the heating roller via a sliding contact mechanism. In the case of this fixing device, the sliding contact mechanism has a rotating tube as a rotating electrode member which is fitted to both ends of the heating roller and rotates integrally with the heating roller. The contacting metal piece is a stationary electrode member, and the two electrode members are arranged so as to slide while maintaining contact even when the heating roller rotates.

[0004]

However, in the fixing device described in the above publication, it is not always easy to maintain good electrical connection between the electrode members constituting the sliding contact mechanism.

[0005] To give a specific example, if an insulator (for example, some dirt or a portion where the surface of the rotary electrode member itself is oxidized) is present on a part of the surface of the rotary electrode member, the rotary electrode member rotates. The insulator periodically comes into contact with the stationary electrode member, and each time the electrical connection between the electrode members forming the sliding contact mechanism is hindered. In addition, when the stationary electrode member vibrates for some reason, the stationary electrode member is momentarily separated from the rotating electrode member, during which the electrical connection between the electrode members forming the sliding contact mechanism is hindered. Is done.

As described above, in the fixing device described in the above publication, the power supply state becomes unstable if the management state of the device is poor, and in that case, it takes time until the heating roller is sufficiently heated. This may cause problems such as insufficient heating. SUMMARY An advantage of some aspects of the invention is to provide a fixing device that supplies power to a heating element fixed to a roller via a sliding contact mechanism. An object of the present invention is to make the electrical connection between the electrode members having a better connection state than before.

[0007]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the fixing device according to the first aspect of the present invention comprises a roller rotatably supported on the apparatus main body side;
A heating element fixed to the roller and generating heat when energized; a rotating electrode member fixed to the roller and rotating integrally with the roller; and a stationary electrode disposed on the apparatus body side and in contact with the rotating electrode member A sliding contact mechanism in which the members are slidably arranged while maintaining contact between the two electrode members during rotation of the roller. Power is supplied to the heating element via the sliding contact mechanism. A fixing device for fixing the recording material to the recording medium by heating the recording material adhered to the surface of the recording medium by contacting the outer peripheral surface of the roller with the recording medium and heating the roller; The electrode member is in pressure contact with the rotating electrode member at two or more contact points pressed by one elastic body.

In this fixing device, the stationary electrode member comprises:
It is structured to be pressed by the elastic body and pressed against the rotating electrode member. As a more specific structure, for example, a stationary electrode member in the form of a leaf spring, the stationary electrode member itself is pressed against the rotating electrode member with elastic deformation, a stationary electrode member,
A structure including a conductor portion serving as an electrode and a spring portion fixed to the conductor portion, and the spring portion presses the conductor portion to the rotating electrode member with elastic deformation may be considered.

The stationary electrode member is in pressure contact with the rotating electrode member by two or more contacts pressed by one elastic body. Therefore, even if a contact failure occurs at one contact, the state of electrical connection at the other contact is maintained, and as a result, the electrical connection between the electrode members is in a better connection state than before. Becomes Therefore, according to this fixing device, the power supply state is more stable than that of the conventional product, and there is no problem that the heating roller is not sufficiently heated. Further, since the number of contacts is greater than the number of elastic bodies, a more compact structure can be achieved as compared with a case where the same number of elastic bodies as the contacts are arranged.

In the fixing device according to the first aspect,
The stationary electrode member is in pressure contact with the rotating electrode member at two or more contact points pressed by one elastic body, but in addition to this elastic body, further includes another elastic body, The other elastic body may have a structure in which the stationary electrode member is pressed against the rotating electrode member at a contact different from the two or more contacts. In this case, the another contact may be one contact or two or more contacts. The number of the other elastic bodies is also arbitrary, and may include one elastic body or two or more elastic bodies.

Further, since current flows through the sheet-shaped heating element, if the roller is made of a material to be a conductor, it is necessary to interpose some kind of insulator between the roller and the roller. When a sheet-like heating element is arranged on the outer peripheral surface side of the roller, it is desirable to take measures such as covering the outer periphery of the heating element with an insulator in order to prevent an electric shock accident or an unexpected short circuit.

The sliding contact mechanism is a mechanism that forms a part of a power supply path to the sheet-shaped heating element, and requires at least two sets of electrodes serving as both poles of the sheet-shaped heating element. However, if the sheet-shaped heating element has three or more current-carrying terminals, sliding contact mechanisms may be provided by the number of terminals. The best effect can be obtained if both of the two sets of sliding contact mechanisms are configured as described above. However, if there are some circumstances, only one of them is configured as described above, and the other is the same as the conventional product. It is not impossible to configure the device, and in that case, a corresponding effect can be obtained.

As the material forming the rotating electrode member and the stationary electrode member, a conductive material such as a metal generally used as a contact material can be arbitrarily selected. Among them, a material having excellent wear resistance is used. The lower the electrical resistance at the contact interface, the better.

In addition, a roller having the same structure as a known fixing device can be arbitrarily adopted. For example, in a fixing device of this type, as a roller, a columnar or cylindrical member composed of a material having high thermal conductivity is generally used.
Metals, particularly aluminum, are preferably used. Further, the roller is preferably such that the recording material does not easily adhere to the outer peripheral surface when the recording material is heated. For example, a roller in which the outer peripheral surface of the roller is coated with a fluororesin-based material is preferable.

Next, in order to achieve the same object as the above-mentioned fixing device, a fixing device according to a second aspect of the present invention includes a roller rotatably supported on the apparatus main body side and a roller. A heating element that is fixed and generates heat when energized, a rotating electrode member that is fixed to the roller and rotates integrally with the roller, and a stationary electrode member that is disposed on the apparatus body side and contacts the rotating electrode member, A sliding contact mechanism that is slidably disposed while maintaining contact between the two electrode members during rotation of the roller, and supplies power to the heating element via the sliding contact mechanism. Heating the roller,
In a fixing device for fixing the recording material to the recording medium by heating the recording material adhered to the recording medium by bringing the outer peripheral surface of the roller into contact with the recording medium, the rotating electrode member has a rotation axis of the roller. The stationary electrode member is in contact with the contact surface of the rotating electrode member at two or more contact points.

In this fixing device, the rotating electrode member comprises:
It has a contact surface substantially orthogonal to the rotation axis of the roller, and the stationary electrode member contacts this contact surface with two or more contacts.
Therefore, even if a contact failure occurs at one contact, the state of electrical connection at the other contact is maintained, and as a result, the electrical connection between the electrode members is in a better connection state than before. Becomes Therefore, according to this fixing device, the power supply state is more stable than that of the conventional product, and there is no problem that the heating roller is not sufficiently heated.

Further, since the contact surface of the rotating electrode member is a surface substantially orthogonal to the rotation axis of the roller, when the stationary electrode member is brought into contact, the stationary electrode member is brought into contact with the rotating electrode member in the contact surface. The contact can be made near the center of rotation. Therefore, the sliding speed of the contact and the sliding distance per one rotation of the roller can be easily reduced, and the wear of both electrode members is suppressed accordingly. Further, since the frictional force is reduced by an amount corresponding to the decrease in the sliding speed of the contact, the load on the drive system of the roller is reduced, and the noise generated due to the friction is also reduced.

In the fixing device according to the present invention, it is desirable that the stationary electrode member has a structure in which the stationary electrode member is pressed by the elastic body and pressed against the rotating electrode member. In that case, the stationary electrode member only needs to be in pressure contact with the rotating electrode member at two or more contact points pressed by one or more elastic bodies. If two or more elastic members are provided, each elastic member presses the stationary electrode member against the rotating electrode member at one contact point, and presses the rotating electrode member at two or more contact points as a whole. Alternatively, each of the elastic bodies may press the stationary electrode member against the rotating electrode member at two or more contact points.

Also, in the fixing device according to the second aspect, similarly to the fixing device according to the first aspect, since a current flows through the sheet-shaped heating element, the roller is made of a material that becomes a conductor. Requires that some kind of insulator be interposed between the roller and the roller. When a sheet-like heating element is arranged on the outer peripheral surface side of the roller, it is desirable to take measures such as covering the outer periphery of the heating element with an insulator in order to prevent an electric shock accident or an unexpected short circuit.

The sliding contact mechanism is a mechanism that forms a part of a power supply path to the sheet-shaped heating element, and requires at least two sets of electrodes serving as both poles of the sheet-shaped heating element. However, if the sheet-shaped heating element has three or more current-carrying terminals, sliding contact mechanisms may be provided by the number of terminals. The best effect can be obtained if both of the two sets of sliding contact mechanisms are configured as described above. However, if there are some circumstances, only one of them is configured as described above, and the other is the same as the conventional product. It is not impossible to configure the device, and in that case, a corresponding effect can be obtained.

As the material forming the rotating electrode member and the stationary electrode member, a conductive material such as a metal generally used as a contact material can be arbitrarily selected. Among them, a material excellent in wear resistance is used. The lower the electrical resistance at the contact interface, the better.

In addition, a roller having the same configuration as a known fixing device can be arbitrarily adopted. For example, in a fixing device of this type, as a roller, a columnar or cylindrical member composed of a material having high thermal conductivity is generally used.
Metals, particularly aluminum, are preferably used. Further, the roller is preferably such that the recording material does not easily adhere to the outer peripheral surface when the recording material is heated. For example, a roller in which the outer peripheral surface of the roller is coated with a fluororesin-based material is preferable.

Next, in a fixing device according to a third aspect of the present invention, in the fixing device, the stationary electrode member is provided with two or more conductive projections serving as contact points, and the stationary electrode member is pressed against the rotating electrode member by pressing the conductive projections.
One or two or more elastic bodies, at least one of the elastic bodies simultaneously presses two or more of the conductive protrusions to form a structure that is pressed against the rotating electrode member, The positional relationship between one elastic body and the two or more conductive protrusions forming the structure is a positional relationship in which the pressing force from the one elastic body is dispersed and acts on the two or more conductive protrusions. It is characterized by having.

According to this fixing device, at least one elastic body simultaneously presses two or more conductive projections to press against the rotating electrode member, and at this time, the pressing force from one elastic body is two. It acts on the above conductive protrusions in a dispersed manner. Therefore, even if there is one elastic body, there is no problem that the pressing force is concentrated on only one conductive protrusion and the contact state of the remaining conductive protrusion becomes unstable. Further, since the number of contacts is greater than the number of elastic bodies, a more compact structure can be achieved as compared with a case where the same number of elastic bodies as the contacts are arranged.

Next, a fixing device according to a fourth aspect of the present invention,
One or more conductive protrusions are provided on the same substrate on which the pressing force from the one elastic body acts, and in particular, a position where the pressing force acts on the substrate and two or more conductive protrusions. The positional relationship between the conductive protrusions and the conductive protrusions is such that the remaining conductive protrusions do not generate a moment for rotating the base material in a direction away from the rotating electrode member with some conductive protrusions as fulcrums. It is characterized by.

According to this fixing device, no matter how much the pressing force acting on the base material from the elastic body is increased, the remaining conductive protrusions are lifted up from the rotating electrode member with some conductive protrusions as fulcrums. There is no. Therefore, two or more conductive protrusions can be reliably brought into contact with the rotating electrode member without strictly adjusting the pressing force of the elastic body.

Next, in the fixing device according to the present invention, the stationary electrode member has two or more conductive protrusions serving as contact points and presses the conductive protrusions to press the conductive protrusions against the rotating electrode member.
And at least two of the elastic members press independently the conductive projections provided one or two or more corresponding to each elastic member, respectively, It is characterized in that it is structured to be pressed against the rotating electrode member.

According to this fixing device, at least two elastic members independently press the conductive projections to press against the rotating electrode members. Therefore, even if a force that hinders good contact between the conductive projection and the rotating electrode member acts on one of the at least two elastic bodies, the remaining elastic bodies are not affected. Good contact between the conductive projection and the rotating electrode member can be maintained.

In each of the fixing devices described above, an image forming mechanism for forming an image by attaching a heat-fusible recording material to a recording medium such as paper, and an image forming mechanism for forming the image by the image forming mechanism. By heating the formed recording medium, the recording material can be employed as the fixing unit in an image forming apparatus including a fixing unit that melts or softens the recording material and fixes the recording material on the recording medium.

Representative examples of such an image forming apparatus include a copying machine, a printer, and a facsimile machine. As an image forming mechanism for forming an image by attaching a heat-fusible recording material, an electric charge is applied to the surface of a drum-type electrophotographic photosensitive member, and light from a laser light source or an LED array is projected onto the surface. An electrophotographic image forming mechanism that forms an electrostatic latent image, develops it with toner, which is a heat-meltable recording material, and transfers an image composed of this toner to a recording medium such as paper, or a dielectric material on the surface An electrostatic recording image forming mechanism that forms an electrostatic latent image on the electrostatic recording paper as a recording medium and develops the electrostatic latent image with a toner that is a heat-fusible recording material, or A solid hot-melt ink-type inkjet image forming mechanism that forms a liquid on a recording medium by thermally melting solid ink at room temperature and ejecting the liquid ink from a recording head can be considered.

[0031]

Next, an embodiment of the present invention will be described with reference to an example. As shown in FIG. 1, the fixing device 1 in the present embodiment is incorporated in a laser printer P. After an image formed of toner (hereinafter, referred to as a toner image) is formed on a sheet as a recording medium in the image forming mechanism 2, the fixing device 1 heats the sheet while transporting the sheet downstream in the sheet transport direction. The toner is fused or softened on the paper to fix the toner image on the paper.

As is well known, the image forming mechanism 2 included in the laser printer P performs an electrophotographic image forming process, and includes a drum type electrophotographic photosensitive member, a charger, an exposing device, a developing device, a transfer device, and a removing device. It is equipped with electric appliances and the like. When forming a toner image on paper, a charge is applied to the surface of a drum-type electrophotographic photosensitive member, and light from a laser light source is projected on the surface to form an electrostatic latent image. The latent image is developed with toner, and the toner image is transferred to a sheet conveyed from upstream to downstream in the sheet conveyance direction.

A paper supply mechanism 3 is disposed upstream of the image forming mechanism 2 in the paper transport direction. The paper supply mechanism 3 sucks paper from either the paper supply cassette unit 4 in which the paper is stacked and stored, or the manual paper supply unit 5 that can supply the paper one by one, and is provided between rollers that rotate the paper. The image forming mechanism 2 is located on the downstream side in the sheet transport direction while being sandwiched.
To the side. Further, a sheet discharging mechanism 6 is disposed downstream of the fixing device 1 in the sheet conveying direction. The paper discharge mechanism 6 transports the paper on which the toner image has been fixed in the fixing device 1 to a tray on the upper part of the main body.

The fixing device 1, the image forming mechanism 2, the paper supply mechanism 3, the paper discharge mechanism 6, and the like are all housed inside a housing 7. Next, the fixing device 1 will be described in detail. The fixing device 1 includes a pair of a heating roller 10 and a pressure roller 12, as shown in FIG. As will be described in detail later, the heating roller 10 is based on a cylindrical body made of aluminum and has a heating element fixed to the inner peripheral surface thereof. The pressure roller 12
Is constructed by providing heat-resistant silicone rubber around a metal shaft.

The heating roller 10 and the pressure roller 12 are arranged in parallel with their outer peripheral surfaces in contact with each other. The pressure roller 12 is rotatably supported by a movable bearing 13, and the movable bearing 13 includes a spring 14.
Powered by As a result, the pressure roller 12 is in pressure contact with the heating roller 10.

Heating roller 10 and pressure roller 1
Paper guides 16 and 17 are provided in the vicinity of 2. The paper guide 16 feeds the paper S conveyed from the image forming mechanism 2 on the upstream side in the paper conveyance direction to the heating roller 1.
0 and a member for guiding to the pressure contact surface of the pressure roller 12. The sheet guide 17 is a member that guides the sheet S, which is sandwiched between the pressure contact surfaces of the heating roller 10 and the pressure roller 12 and is transmitted with the rotation of both rollers, to the sheet discharge mechanism 6 further downstream in the sheet conveying direction. It is.

A temperature fuse 19 is mounted on the upper cover 18 provided above the heating roller 10. The thermal fuse 19 is disposed opposite to the outer peripheral surface of the heating roller 10, and when an abnormal overheating of the heating roller 10 occurs due to a runaway of the control device or the like, the thermal fuse 19 is disconnected by receiving the heat, and the power supply circuit cannot be energized. It is to be in a state. The temperature fuse 19 is disconnected when the temperature exceeds a predetermined temperature condition, and cannot be returned to an energizable state thereafter. However, the temperature fuse 19 is replaced with a predetermined temperature condition. Even if a thermostat whose connection / disconnection is reversibly switched is used, the same abnormal overheating can be prevented. Incidentally, the fixing device 1 is further provided with a temperature sensor (not shown) for detecting the surface temperature of the heating roller 10 in addition to the temperature fuse 19, and the surface temperature of the heating roller 10 is constantly detected by the temperature sensor. Monitoring is performed so that an appropriate temperature is maintained.

As shown in FIG. 3, the heating roller 10 itself has a hollow cylindrical aluminum roller body 31 as a base material, and has an adhesion preventing layer 32 on the outer peripheral surface of the roller body 31.
Is formed on the inner peripheral surface of the roller body 31 from the outer peripheral side.
3 of the heat-resistant insulating layer 33, the heat-generating layer 34, and the second heat-resistant insulating layer 35
Layers, and these three layers of film material are pressed against the roller body 31 by a press-contact elastic body 36 disposed inside the film material.
It is structured so as to be sandwiched and held between the inner peripheral surface and the inner peripheral surface.

The adhesion preventing layer 32 is provided to prevent the toner on the recording medium from adhering to the surface of the heating roller 10 during the fixing process. It is formed by coating a fluororesin-based material with excellent properties and mold release properties, and its thickness is about 10
３０30 μm.

The pressing elastic body 36 has a hollow cylindrical shape formed of a silicone sponge, and has an outer diameter in a stress-free state larger than that when it is arranged inside the heating roller 10. When it is arranged inside the heating roller 10, the pressing elastic body 36 is stretched in the axial direction to reduce the outer diameter, and is arranged inside the heating roller 10 in that state, and the stretching is stopped. As a result, the pressing elastic body 36
Is compressed in the axial direction and swells in the direction in which the outer diameter returns to its original state, pressing the first heat-resistant insulating layer 33, the heat-generating layer 34, and the second heat-resistant insulating layer 35, and sandwiching them between the roller body 31. Becomes

The heating layer 34 is constituted by a sheet heating element 50 shown in FIG. This sheet heating element 50
Is an insulating base material 51 made of a polyimide resin film.
And a flexible sheet on which a resistance heating element 55 made of a stainless steel foil film is adhered. When the heating element is disposed in the heating roller 10, the resistance heating element 55 is
5 are arranged so as to be in contact with 5. The resistance heating element 55
It is composed of a heating pattern portion 55a functioning as a heating element, a first current-carrying terminal 55b and a second current-carrying terminal 55c connected to both ends of the heat-generating pattern portion 55a, respectively. The structure is such that when a current flows between them, the heat generating pattern portion 55a generates heat. The heating pattern portion 55a of such a resistance heating element 55
Can be formed by attaching a stainless steel foil film to the insulating base material 51 and performing an etching process on the stainless steel.

Each of the first heat-resistant insulating layer 33 and the second heat-resistant insulating layer 35 is a polyimide resin film material.
Has excellent heat resistance and insulation properties. The first heat-resistant insulating layer 33 forms a double insulating layer together with the insulating base material 51 of the sheet-shaped heating element 50, and the double insulating layer prevents the electrical connection between the roller body 31 and the resistance heating element 55. doing.
With such a structure, even if one of the first heat-resistant insulating layer 33 and the insulating base material 51 is damaged for some reason, the roller body 31 and the resistance heating element 55 are immediately electrically connected. Can be prevented. The second heat-resistant insulating layer 35 prevents the resistance heating element 55 and the pressure-contact elastic body 36 from directly contacting each other. With such a structure, the resistance heating element 55 is locally overheated for some reason, and the temperature of the abnormally heated portion is changed by the pressing elastic body 3.
Even when the temperature exceeds the heat-resistant temperature of the silicone sponge 6, it is possible to prevent a sudden increase in the temperature of the press-contact elastic body 36 itself and an accident such as a fire accompanying the temperature rise.

The heating roller 10 constructed as described above
Is rotatably supported by bearings 60, 60 fixed to the body frame, as shown in FIG. The bearing 60 is formed by molding a composite resin material in which carbon is dispersed as a conductive filler in PPS (polyphenylene sulfide resin) serving as a matrix.
It has heat resistance and conductivity that do not soften up to about 50 ° C. to 260 ° C. Therefore, as long as the heating roller 10 is used under a normal temperature condition (about 200 ° C.), the bearing 60 does not deform. Also, the heating roller 1
Reference numeral 0 denotes a state in which the heating roller 10 is electrically connected to a grounded metal part or the like via the bearings 60, 60, thereby preventing the heating roller 10 from being charged. A driving gear 62 is mounted on one end of the heating roller 10, and a driving force from a motor (not shown) is transmitted to the driving gear 62 to rotate the heating roller 10. The drive gear 62 is made of PPS and has the same heat resistance as the bearing 60.

Further, sliding contact mechanisms 70, 70 are formed at both ends of the heating roller 10. Each sliding contact mechanism 70 includes a rotating electrode member 71 fixed to the heating roller 10 and rotating integrally with the heating roller 10, and a stationary electrode member 72 fixed to the main body frame and in contact with the rotating electrode member 71.
Consists of

The rotating electrode member 71 is, as shown in FIG.
An electrode 74 made of a copper-based alloy (for example, phosphor bronze) and a holder 75 made of insulating heat-resistant resin (for example, PPS) are assembled. The current collector plate 74a, which forms the stationary electrode side contact surface of the electrode portion 74, has a stationary electrode
In a state of being substantially perpendicular to the rotation axis. In this arrangement, the current collecting plate 74a is sandwiched between the projections 75a and 75b projecting from the inner peripheral surface of the holder portion 75, and the positioning piece 74b of the electrode portion 74 is guided by the guide of the holder portion 75. It fits in the groove 75c, and the
And the holder portion 75 are prevented from being relatively displaced. Further, the rotating electrode member 71 is provided with a cylindrical portion 75d of the holder portion 75.
Is inserted into the heating roller 10 in such a manner as to be inserted inside the sheet-shaped heating element 50. In this state, the holder 7
The flange 75e on the outer periphery of the roller 5 is in contact with the end face of the roller body 31. The flange 75e prevents the rotating electrode member 71 from being excessively pushed into the heating roller 10. Further, the contact 74c forming the heating element side contact surface of the electrode part 74 is urged by the leaf spring part 74d and is in pressure contact with the first energizing terminal 55b of the sheet-like heating element 50. The rotation of the rotating electrode member 71 with respect to the heating roller 10 and the heating roller 10
From falling off is prevented.

The stationary electrode member 72 includes a power supply plate 77 made of a copper-based alloy (for example, phosphor bronze) and a power supply plate 7.
7 and a conductive projection 78 made of a silver-based alloy provided at an end of the metal alloy. As shown in FIG. 5, the power supply plate 77 functions as a leaf spring (elastic body) whose one end is a fixed end screwed to the upper cover 18 and the other end is a free end displaced with elastic deformation. Things. On a free end side of the power supply plate 77, a support substrate 77a having a positional relationship substantially parallel to the current collector plate 74a is formed. As shown in FIG. 7, five conductive protrusions 78 are formed on the support substrate 77a. Fixed. The stationary electrode member 7 thus configured
Reference numeral 2 denotes five conductive projections 78 pressed by the power supply plate 77 and pressed against the stationary electrode side contact surface of the rotating electrode member 71. Then, the rotating electrode member 71
The two are electrically connected to each other at a pressure contact portion between the heating roller 10 and the stationary electrode member 72. Particularly, even when the heating roller 10 rotates, the heating roller 10 slides while maintaining the contact, and maintains a state in which both are electrically connected. it can.

Each of the conductive projections 78 is located at a position where the pressing force from the power supply plate 77 acts in a dispersed manner, and particularly when a certain pressing force from the power supply plate 77 is applied. The supporting substrate 7 moves in a direction in which the remaining conductive protrusions 78 are separated from the rotating electrode
It is arranged at a position where no moment for rotating 7a is generated. More specifically, in the case of the present embodiment, the five conductive protrusions 78 are arranged so as to have a line-symmetrical positional relationship, and the five conductive protrusions 78 are positioned at the same line-symmetrical positions with respect to the center line that is the center of symmetry. The pressing force from the power supply plate 77 acts on the support substrate 77a at a position farther from the center line than the one conductive protrusion 78, so that the five conductive members can be rotated without rotating the support substrate 77a. All of the protruding protrusions 78 come into pressure contact with the rotating electrode member 71. Therefore, the load is not extremely concentrated only on the specific conductive protrusion 78, and the power supply plate 7
Even if the pressing force of 7 is relatively strong, the support substrate 77 a is not twisted and only the specific conductive protrusion 78 does not float from the rotating electrode member 71. Therefore, there is no possibility that uneven wear is caused only on the specific conductive protrusion 78 or connection failure is not caused.

The sliding contact mechanism 70 at the other end
Has a similar structure. The sheet-like heating element 50 is provided with the two sliding contact mechanisms 70, 70 as both poles.
AC power (or DC power) is supplied. As described above, the fixing device 1 employs the configuration according to the first aspect, and the stationary electrode member 72 includes the power supply plate 7.
7 (corresponding to one elastic body in the first aspect), the five conductive projections 78 (corresponding to two or more contact points in the first aspect) pressed against the rotating electrode member 71 by pressing. I have. Therefore, even if contact failure occurs at a certain conductive protrusion 78, the remaining conductive protrusion 7
8, the electrically connected state is maintained, and as a result, the electrical connection between the electrode members becomes a better connected state than before. Therefore, according to the fixing device 1,
The power supply state is more stable than the conventional product, and there is no problem that the heating roller 10 is not sufficiently heated.

The fixing device 1 employs the structure described in the second aspect, and the stationary electrode side contact surface of the rotating electrode member 71 is a surface substantially orthogonal to the rotation axis of the heating roller 10. I have. Therefore, when the stationary electrode member 72 is brought into contact with the stationary electrode member 72, the stationary electrode member 72 can be brought into contact with the vicinity of the center of rotation in the contact surface of the rotating electrode member 71. The distance can be easily reduced, and the wear of both electrode members is suppressed accordingly. Further, since the frictional force is reduced by an amount corresponding to the reduction in the sliding speed of the contact, the load on the drive system of the heating roller 10 is reduced, and the noise generated due to the friction is also reduced.

Further, the fixing device 1 is characterized in that
The power supply plate 77 (corresponding to one elastic body in the third aspect of the present invention) simultaneously presses the five conductive protrusions 78 and presses the conductive protrusions 78 against the rotating electrode member 71. The pressing force from the plate 77 acts on the five conductive protrusions 78 in a dispersed manner. Therefore, even if there is one elastic body, there is no problem that the pressing force is concentrated on only one conductive protrusion 78 and the contact state of the remaining conductive protrusions 78 becomes unstable. In addition, since even one power supply plate 77 can increase the number of contacts beyond the number, a more compact structure can be achieved as compared with the case where the same number of power supply plates 77 as the contacts are arranged.

In addition, the fixing device 1 is characterized in that
Even if the pressing force applied from the power supply plate 77 (corresponding to the elastic body in claim 4) to the support substrate 77a (corresponding to the base material in claim 4) is increased, The remaining conductive protrusions 78 do not float up from the rotating electrode member 71 with some of the conductive protrusions 78 as fulcrums. Therefore, the power supply plate 7
Even if the pressing force of 7 is not strictly adjusted, the five conductive protrusions 78 can be brought into contact with the rotating electrode member 71 without fail.

Although the embodiments of the present invention have been described above, various specific embodiments other than those described above are conceivable for the embodiments of the present invention. For example, the fixing device 1
Has adopted a configuration in which five conductive protrusions 78 are provided on a power supply plate 77, which is one elastic body, as the stationary electrode member 72. However, two or more independent elastic bodies are provided, and It is also possible to adopt a structure in which each elastic body independently presses one or two or more conductive projections provided corresponding to the elastic body and presses against the rotating electrode member.

More specifically, for example, in FIGS.
The stationary electrode member 80 includes a first power supply plate 81 and a second power supply plate 82, each of which is independently elastically deformable, a conductive protrusion 83 fixed to the first power supply plate 81, and a second power supply plate. 82 and two conductive projections 84 fixed to the projection 82. Although the first power supply plate 81 and the second power supply plate 82 are integrated on the fixed end side, each of them independently functions as a leaf spring similar to the above-described power supply plate 77 on the free end side, and each conductive projection 83 and 84 are pressed against the stationary electrode side contact surface of the rotating electrode member 71. Such a stationary electrode member 80
, The first power supply plate 81 and the conductive protrusion 83
The portion made of the above-mentioned structure adopts the structure of the above-described claims 1 to 4, and operates in exactly the same way as the stationary electrode member 72, and has the above-described effect. Moreover,
The stationary electrode member 80 also adopts the configuration described in claim 5, and the first power supply plate 81 or the second power supply plate 82 presses the conductive protrusions 83 and 84 independently of each other to rotate the rotary electrode member 71. Even if a force that hinders good contact between the conductive projection and the rotating electrode member 71 is applied to one of the power supply plates, the other power supply plate is not affected at all. Good contact between the conductive protrusions and the rotating electrode member 71 can be maintained.

Further, the fixing device 1 has both the constitutions of the first and second aspects.
Each of the configurations described in claim 1 or 2 may be provided independently. For example, as shown in FIG. 10A, a cylindrical rotating electrode member 87 is provided at an end of a heating roller 86 as shown in FIG.
And a stationary electrode member 88 which comes into contact with the outer peripheral surface of the rotating electrode member 87 is provided.
Is a power supply plate 88a as one elastic body, and two conductive protrusions 88b fixed to the power supply plate 88a.
And a structure in which the two conductive protrusions 88b are pressed against the rotating electrode member 87. However, with such a structure, the contact point between the rotating electrode member 87 and the stationary electrode member 88 is located relatively far from the rotation axis of the heating roller 86, and the sliding speed and the sliding distance at the contact point are set. In order to suppress the abrasion of the contact and the vibration and noise coming out of the contact, it is preferable that
It is better to have the described configuration.

For example, as shown in FIG. 10B, an end of the heating roller 90 has a contact surface substantially orthogonal to the rotation axis of the heating roller 90 as shown in FIG. The rotating electrode member 91 is provided, and the stationary electrode member 9 in contact with the contact surface of the rotating electrode member 91 is provided.
2, the stationary electrode member 92 has a structure including two power supply plates 93 and 94, which are two elastic bodies, and conductive protrusions 95 and 96 fixed to each power supply plate. The rotation electrode member 9 is formed by the projections 95 and 96.
One that is pressed against 1 can be considered. However, such a structure requires the elastic members as many as the number of contacts, and it is easy to have a large structure for the purpose of securing an arrangement space for the elastic members. It is better to have the configuration of claim 1 together.

In addition, in the above embodiment, the case where the fixing device 1 is built in the laser printer P has been described as an example.
The fixing device 1 is an image forming apparatus (for example, a copying machine, a printer, a facsimile machine, or the like) having an image forming mechanism for forming an image by attaching a heat-fusible recording material to a recording medium such as paper. If there is, it can be adopted as a device for fixing an image formed by the image forming mechanism on a recording medium.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic structure of a laser printer having a fixing device therein.

FIG. 2 is a longitudinal sectional view illustrating a schematic structure of a fixing device.

FIG. 3 is a cross-sectional view illustrating a cross-sectional structure of a heating roller.

FIG. 4 is a plan view showing a sheet heating element.

FIG. 5 is a sectional view taken along line AA of the schematic structure of the fixing device.

6 is an enlarged partial cross-sectional view in which the vicinity of one of the sliding contact mechanisms in FIG. 5 is enlarged.

FIG. 7 is a side view showing only a main part to show a contact position of the sliding contact mechanism.

FIG. 8 is an enlarged partial cross-sectional view of a sliding contact mechanism of another embodiment different from FIG.

9 is a side view of the sliding contact mechanism shown in FIG.

FIGS. 10A and 10B are perspective views each showing still another sliding contact mechanism.

[Explanation of symbols]

P ... Laser printer, 1 ... Fixing device, 2 ...
Image forming mechanism, 3 paper feed mechanism, 4 paper feed cassette section, 5 manual paper feed section, 6 paper discharge mechanism, 7 housing, 10, 86, 90 ... Heating roller, 12 ... Pressure roller, 13 ... Movable bearing, 14 ... Spring, 16, 17 ... Paper guide, 1
8 top cover, 19 thermal fuse, 31
..The roller body, 32 an adhesion preventing layer, 33 a first heat-resistant insulating layer, 34 a heat-generating layer, 35 a second heat-resistant insulating layer, 36 a pressure elastic body, 50. ..Sheet heating elements, 51 ... insulating base material, 55 ... resistance heating elements, 5
5a: heating pattern portion, 55b: first energizing terminal, 55c: second energizing terminal, 60: bearing,
62: drive gear, 70: sliding contact mechanism, 71,
87, 91 ... rotating electrode member, 72, 80, 88, 9
2 ... stationary electrode member, 74 ... electrode part, 74a ...
・ Current collecting plate, 74b: positioning piece, 74c: contact, 74d: leaf spring portion, 75: holder portion, 75
a, 75b: projection, 75c: guide groove, 75d
... Cylindrical part, 75e ... Flange, 77, 88a, 8
1, 82, 93, 94 ... power supply plate, 77a ...
・ Supporting substrate, 78, 83, 84, 88b, 95, 96
..Conductive projections.

Claims (5)

[Claims] A roller rotatably supported by the apparatus main body; a heating element fixed to the roller and generating heat when energized; a rotating electrode member fixed to the roller and rotating integrally with the roller; A sliding contact mechanism comprising a stationary electrode member disposed on the apparatus body side and in contact with the rotating electrode member, wherein the stationary electrode member is slidably disposed while the two electrode members maintain contact when the roller rotates. Power is supplied to the heating element via the sliding contact mechanism to heat the roller, and the outer peripheral surface of the roller is brought into contact with the recording medium to heat the recording material attached to the recording medium surface. Accordingly, in the fixing device for fixing the recording material to a recording medium, the stationary electrode member may be in pressure contact with the rotating electrode member at two or more contacts in a state pressed by one elastic body. Feature Chakusochi. 2. A roller rotatably supported on the apparatus main body side, a heating element fixed to the roller and generating heat when energized, a rotating electrode member fixed to the roller and rotating integrally with the roller, and A sliding contact mechanism comprising a stationary electrode member disposed on the apparatus body side and in contact with the rotating electrode member, wherein the stationary electrode member is slidably disposed while the two electrode members maintain contact when the roller rotates. Power is supplied to the heating element via the sliding contact mechanism to heat the roller, and the outer peripheral surface of the roller is brought into contact with the recording medium to heat the recording material attached to the recording medium surface. In the fixing device for fixing the recording material to a recording medium, the rotating electrode member has a contact surface substantially orthogonal to a rotation axis of the roller, and the stationary electrode member has two or more contact points. In front of the rotating electrode member A fixing device which is characterized in that in contact with the contact surface. 3. The fixing device according to claim 1, wherein the stationary electrode member presses against the rotating electrode member by pressing two or more conductive protrusions serving as contact points and pressing the conductive protrusions. A structure in which at least one of the elastic members simultaneously presses two or more of the conductive protrusions to press against the rotating electrode member. None, one elastic body and 2
A fixing device, wherein the positional relationship with one or more conductive protrusions is such that the pressing force from the one elastic body acts on the two or more conductive protrusions in a dispersed manner. 4. The fixing device according to claim 3, wherein the two or more conductive protrusions are provided on the same base material on which the pressing force from the one elastic body acts. The positional relationship between the position at which the pressing force acts on the material and the two or more conductive protrusions is determined based on the fact that the remaining conductive protrusions are separated from the rotating electrode member with some conductive protrusions as fulcrums. A fixing device characterized in that the fixing member has a positional relationship in which a moment for rotating the material is not generated. 5. The fixing device according to claim 1, wherein the stationary electrode member presses the conductive protrusions and the rotating member by pressing the conductive protrusions. At least two of the elastic members are each independently provided with one or more conductive projections provided corresponding to each of the elastic members. Wherein the fixing device is configured to be pressed against the rotating electrode member so as to be pressed against the rotating electrode member.