JPH10312128A - Thermal fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the contact of electrode members with power feeding brushes and to reduce contact resistance by concentrically arranging a heat generating roller, the electrode members and the power feeding brushes. SOLUTION: A thermal roller 31 is provided with an exothermic resistance layer on the inner surface side of a cylindrical base body consisting of an electrically conductive member made of metal such as an aluminum alloy, with an insulated layer interposed. The disk-like electrode members 39A and 39B are fixed/integrated inside in the vicinities of both ends in the axial direction of the thermal roller 31. The top end parts of the electrode members 39A and 39B are formed to have projection shapes and the contact surface parts 39A1 and 39B1 existed in the vicinities of the axial centers of the rotations of the electrode members 39A and 39B come into rotatable/slidable contact with the top end parts 42A1 and 42B1 of the feeding brushes 42A and 42B. In this device, the electrode members 39A and 39B and the feeding brushes 42A and 42B are arranged in the center of the rotation of the thermal roller 31. Thus, the contact of the center of the thermal roller 31 is made at the low place of a sliding speed and stable power feeding can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device used in an image forming apparatus such as an electrophotographic copying machine, a printer or a facsimile, and more particularly, to a heat generating layer having a cylindrical core with an insulating layer interposed therebetween. The present invention relates to a heat roller for heating and fixing which is configured to heat the core by forming and supplying power to the resistance heating layer, thereby improving thermal efficiency.

[0002]

2. Description of the Related Art A conventional heat roller for a heat fixing device using a halogen lamp as a heat source has the following problems.

(1) The heat generated by a halogen lamp has low thermal efficiency and large power consumption.

(2) Since the life of the halogen lamp is shorter than the life of the apparatus, the halogen lamp needs to be replaced.

(3) Since the replacement of the halogen lamp is made possible, the structure of the heat fixing device becomes complicated.

As a conventional heat fixing device for solving the above-mentioned problems, a resistance heating film and a release layer are laminated on the outer peripheral surface of an insulating roller base, and both ends thereof can be rotated to a casing via a bearing. It consists of a cylindrical heating element roller supported on, and a pressure roller that rotates by pressing against this,
There has been provided an image forming apparatus in which the toner image is fused and fixed to the transfer material while nipping and transporting the transfer material on which the toner image has been transferred in the previous steps of charging, exposing, developing and transferring.

[0007] Japanese Patent Application Laid-Open No. 63-2544 shown in FIG.
No. 79 discloses a heat fixing device in which a heat generating film layer 1B and a release layer 1C are sequentially laminated on the outer peripheral surface of a cylindrical substrate 1A, and a conductive portion 1D which is electrically connected to the heat generating film layer 1B is formed on at least one end side. Both ends of the heat generating roller 1 are rotatably attached to a casing 3 via a bearing 2, and a holder 4 for holding the bearing 2 is provided outside the casing 3.
An external heating roller type that holds a power supply brush 5 that contacts the conductive portion 1D.

[0008] Japanese Patent Application Laid-Open No. Sho 62-1503 shown in FIG.
No. 68, a heating roller 1 for heat fixing includes a heating layer 1B on a cylindrical base 1A via an insulating layer 1E, and is electrically connected to the heating layer 1B at both ends of the heating layer 1B. This is an inner surface type heating roller type that includes a disk-shaped electrode member 1F and is configured to supply power to the heating film layer 1B from the power supply brush 5 via the central axis 1G of the electrode member 1F.

Japanese Patent Laid-Open No. 62-2159 shown in FIG.
No. 86 discloses a fixing device in which a heating roller 1 includes a cylindrical substrate 1A, a release layer 1C formed on the outer peripheral surface of the cylindrical substrate 1A, and an inner peripheral surface of the cylindrical substrate 1A. Insulation layer 1
E, a heat generating film layer 1B and an insulating layer 1H are sequentially formed, and
An inner surface type in which a conductive portion 1D is formed in contact with both ends in the axial direction of the heat generating film layer 1B and protrudes from the surface of the insulating layer 1H, and a power supply brush 5 is pressed against the conductive portion 1D from the inside to supply power. Heating roller type.

[0010]

However, in the power supply brush used in these heat fixing devices, the pressure contact force of the power supply brush 5 is applied to the side circumferential surface of the rotating conductive portion 1D (or the central shaft 1G). To act as a friction brake,
Wear powder is generated between the power supply brush 5 and the conductive portion 1D.
In particular, the power supply brush 5 is generally formed mainly of copper or graphite, has a low hardness, and further has a heating film layer 1B.
Due to the influence of heat, abrasion is caused by sliding contact with the rotating conductive portion 1D, thereby generating abrasion powder. For this reason, there is a problem that the abrasion powder adheres to the surface of the release layer 1C, and this is further transferred to a transfer material, thereby causing image quality defects.

Further, an eccentric force is applied to the rotating shaft of the heating element roller 1 by the pressure contact force of the power supply brush 5, and an excessive load is applied to the bearing 2 supporting the heating element roller 1 due to the eccentric load, causing wear. There is a problem that the heating element roller 1 rotates irregularly.

A first object of the present invention is to stabilize the contact between the electrode member and the power supply brush and reduce the contact resistance (corresponding to claims 1 to 4).

A second object of the present invention is to prevent a bearing (such as a sliding bearing made of resin) for supporting a heat roller and deterioration of constituent members due to a rise in the temperature of a support portion, an increase in torque, deformation, breakage, and the like. (Corresponding to claim 5).

A third object of the present invention is to prevent electric noise at a contact portion between an electrode member and a power supply brush from being emitted to the outside of the heat fixing device (corresponding to claims 6 to 8). .

A fourth object of the present invention is to prevent the electrode member from dropping in the axial direction (inside) of the heat roller due to the pressing force of the power supply brush to the electrode member (corresponding to claim 9).

A fifth object of the present invention is to prevent a reduction in insulation distance and a short circuit due to abrasion powder at a contact portion between an electrode member and a power supply brush (corresponding to claim 10).

A sixth object of the present invention is to prevent a pressing operation failure due to thermal deformation, accuracy and the like of an insulating holder when pressing a power supply brush against an electrode member. Correspondence).

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems.

According to a first aspect of the present invention, there is provided a heating and fixing apparatus according to the first aspect of the present invention, wherein the recording paper passes through a pressure contact position between a driving and rotating heat roller and a pressure roller rotating while being pressed against the heat roller. In the heat fixing device for heating and fixing the unfixed developer image formed on the surface of the recording paper, the heat roller has an inner surface provided with a heating resistance layer via an insulating layer on an inner surface of a cylindrical metal core. A heat roller, wherein the heat-fixing device is provided inside in the vicinity of both ends of the heat roller in the roller axis direction, and is a disk-shaped electrode member electrically connected to the heat generating resistance layer; A conductive power supply brush for supplying power by sliding contact with the electrode member is provided, and the heat roller, the electrode member, and the power supply brush are arranged concentrically.

Further, in the heat fixing device according to the present invention, the recording paper is passed through a pressure contact position between a driving and rotating heat roller and a pressure roller rotating while pressing against the heat roller. A heat fixing device for heating and fixing an unfixed developer image formed on the surface of a recording paper, wherein the heat roller has an inner surface type heat source provided with a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar. A roller, wherein the heat fixing device is
The heat roller includes a disk-shaped electrode member provided inside and near both ends in the roller axis direction of the heat roller and electrically connected to the heat generating resistance layer. Supported by a bearing member fixed to the support member of
The inner end face of the electrode member fixed inside the heat roller,
At least from the installation position of the bearing member or the support member,
It is characterized by being arranged inside.

Further, in the heat fixing apparatus according to the present invention, the recording paper is passed through a pressure contact position between a driving and rotating heat roller and a pressure roller rotating while pressing against the heat roller. A heat fixing device for heating and fixing an unfixed developer image formed on the surface of a recording paper, wherein the heat roller has an inner surface type heat source provided with a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar. A roller, wherein the heat fixing device is
A disk-shaped electrode member provided inwardly near both ends of the heat roller in the roller axis direction and electrically connected to the heating resistance layer; and a conductive member for slidingly contacting the electrode member to supply electric power. A power supply brush, a holder for holding the power supply brush, a shield member for covering the vicinity of a sliding contact portion between the power supply brush and an electrode member provided near both ends of the rotating heat roller, and A grounding means for grounding the shield member is provided to reduce electrical noise emitted from the vicinity of the sliding contact portion to the outside of the heat fixing device.

Further, in the heat fixing apparatus according to the ninth aspect of the present invention, the recording paper is passed through a pressure contact position between a driving heat rotating roller and a pressure roller rotating while pressing against the heat roller. Thus, in a heat fixing device that heats and fixes an unfixed developer image formed on the surface of a recording paper, the heat roller has an inner surface type including a heating resistance layer via an insulating layer on an inner surface of a cylindrical metal core. A heat roller, wherein the heat-fixing device is provided inside in the vicinity of both ends of the heat roller in the roller axis direction, and is a disk-shaped electrode member electrically connected to the heat generating resistance layer; And a conductive power supply brush for supplying electric power by pressing against the rotating shaft direction of the heat roller, wherein the power supply brush has a cylindrical portion fitted to the inner cylindrical surface of the heat roller, and a shaft mounted on an end surface of the heat roller. And a flange that abuts from It is an.

Further, in the heat fixing apparatus according to the present invention, the recording paper is passed through a pressure contact position between a driving and rotating heat roller and a pressure roller rotating while pressing against the heat roller. Thus, in a heat fixing device that heats and fixes an unfixed developer image formed on the surface of a recording paper, the heat roller has an inner surface type including a heating resistance layer via an insulating layer on an inner surface of a cylindrical metal core. A heat roller, wherein the heat-fixing device is provided inside in the vicinity of both ends of the heat roller in the roller axis direction, and is a disk-shaped electrode member electrically connected to the heat generating resistance layer; And a conductive power supply brush for supplying electric power by pressing against the rotation axis direction of the heat roller, a holder for holding the power supply brush, and a cover member for covering the outside of the power supply brush, further comprising: On the inner side of the holder, A partition chamber by a partition wall is provided below the sliding contact portion with the electrode member, and abrasion powder generated and dropped due to frictional contact between the electrode member and the power supply brush is accommodated in the partition chamber. Things.

Further, in the heat fixing apparatus according to the present invention, the recording paper may be passed through a pressure contact position between a driving and rotating heat roller and a pressure roller rotating while pressing against the heat roller. Thus, in a heat fixing device that heats and fixes an unfixed developer image formed on the surface of a recording paper, the heat roller has an inner surface type including a heating resistance layer via an insulating layer on an inner surface of a cylindrical metal core. A heat roller, wherein the heat-fixing device is provided inside in the vicinity of both ends of the heat roller in the roller axis direction, and is a disk-shaped electrode member electrically connected to the heat generating resistance layer; A conductive brush for supplying electric power by pressing against the rotation axis of the heat roller and a conductive guide member for holding the power brush movably in the rotation axis direction, and an insulation for fixing and holding the guide member It has a It is an.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of an embodiment of the present invention, an image forming section of an image forming apparatus provided with a heat fixing device of the present invention will be described with reference to a sectional view of FIG.

In FIG. 1, reference numeral 10 denotes a photosensitive drum as an image carrier, 11 denotes a scorotron charger, 12 denotes a pre-charging static eliminator (PCL), 13 denotes an exposure optical path by an image exposure means (not shown), and 14 denotes a charge erasing device. LED array, 15 is a developing device, 16 is a transfer electrode, 17 is a separation electrode, 18 is a separation claw,
19 is a cleaning device, 21 is a registration roller pair of a paper feeding device, 22 is a paper feeding roller pair, 30 is a heat fixing device, P
Is a transfer material.

The heat fixing device 30 includes a heat roller 31, a pressure roller 32, a cleaning roller 33, and a temperature sensor 3.
4, a separation claw 35, a paper discharge roller 36, and the like.

FIGS. 2 to 6 show a heat fixing device according to claims 1 to 4 of the present invention.

FIG. 2A is a side sectional view of the heat roller 31.
FIG. 2B is a front sectional view of the heat roller 31.

The heat roller 31 of the present invention is a cylindrical base (core metal) made of a metal conductive member such as an aluminum alloy.
On the inner surface side of 312, a heat generating resistance layer 3 is interposed via an insulating layer 313.
And a disk-shaped electrode member 39 </ b> A, 39 </ b> B that is provided inside the heating resistor layer 314 near both ends in the roller axis direction and is electrically connected to the heating resistor layer 314. Roller. Reference numeral 311 denotes a release layer made of a fluorine resin which covers the surface of the cored bar 312. Disk-shaped electrode members 39A and 39B electrically connected to the heating resistance layer 314 are inserted and fixed inside the heating resistance layer 314 near both ends in the roller axis direction.

(First Embodiment) FIG. 3 is a sectional view of a main part of a heat fixing device according to claims 1 to 4 of the present invention.

Disc-shaped electrode members 39A and 39B are fixed inside the heat roller 31 near both ends in the axial direction.
It is integrated. The electrode member 39A of this embodiment,
The tip of 39B has a convex shape, and the contact surface portions 39A ₁ and 39B ₁ near the center of the rotation axis form power supply brushes 42A and 42B.
B is in sliding contact with the tip portions 42A ₁ and 42B ₁ of B. The contact surface portions 39A ₁ and 39B ₁ or the tip portions 42A ₁ and 42B ₁ may be formed as a spherical surface or a curved surface having a large radius of curvature.

The outer peripheral surfaces near both ends in the axial direction of the heat roller 31 are rotatably supported by heat-insulating bearing members (hereinafter, referred to as bearings) 41A, 41B fixed to the side plates 40A, 40B.

The contact surface 39 of the electrode member 39A on the left side in the figure is shown.
The A _1, the distal end portion 42A ₁ of the power supply brush 42A slides rotatably. The holder 43A is positioned and fixed in the cover member 44A. The cover member 44A is fixed to the side plate 40A. A pressing spring 45A is provided between the inner wall of the cover member 44A and the rear end of the power supply brush 42A.
Is inserted. The pressing spring 45 </ b> A
By pressing the A, it is pressed against the contact surface 39A ₁ of the electrode member 39A. In this crimping state, the contact surface portion 39A ₁ is rotatably sliding contact on the tip portion 42A ₁ of the power supply brush 42A.

One end of a lead wire 46A is fixed to a part of the side surface of the power supply brush 42A. The other end of the lead wire 46A is connected to a power supply terminal 47A. Power supply terminal 47A
Is connected to a power supply via wiring means (not shown).

The contact surface portion 39 of the electrode member 39B on the right side in the drawing.
The B _1, the tip portion 42B ₁ of the power supply brush 42B slides rotatably. The outer periphery of the power supply brush 42B is a holder 43
The heat roller 31 slides on the inner surface of B and is guided so as to be movable in the axial direction of the heat roller 31. The holder 43B is positioned and fixed to the cover member 44B. The cover member 44B is fixed to the side plate 40C. A pressing spring 45B is provided between the inner wall of the cover member 44B and the rear end of the power supply brush 42B.
Is inserted. The pressing spring 45 </ b> B
By pressing the B, it is pressed against the contact surface 39B ₁ of the electrode member 39B. In this crimping state, the contact surface portion 39B ₁ is rotatably sliding contact to the distal portion 42B ₁ of the power supply brush 42B.

One end of a lead wire 46B is fixed to a part of the side surface of the power supply brush 42B. The other end of the lead wire 46B is connected to a power supply terminal 47B. Power supply terminal 47B
Is connected to a power supply via wiring means (not shown).

A gear 50 is provided at the right end of the heat roller 31 in the figure.
Has been fixed. The gear 50 is connected to a drive source (not shown) to drive and rotate the heat roller 31.

The power supplied from the power supply is input to the power supply terminal 47A via the wiring means, and is conducted from the lead wire 46A to the power supply brush 42A, thereby driving and rotating the heat roller 31.
The heat generating resistance layer 31 of the heat roller 31 from the electrode member 39A inside
4 to generate heat, and further form an electric path that conducts from the electrode member 39B to the power supply brush 42B, the lead wire 46B, and the power supply terminal 47B.

The heat fixing device according to the present invention has
A, 39B and the power supply brushes 42A, 42B
By arranging at the center of rotation of one, at least the center of the heat roller 31 comes into contact, and contacts at a place where the sliding speed is low,
Stable power supply can be performed.

Also, the power supply brushes 42A and 42B are brought into contact with the rotation centers of the electrode members 39A and 39B, which are hardly affected by the mounting accuracy of the parts such as runout and surface condition. 42A,
The contact between 42B can be stably maintained.

(Second Embodiment) FIG. 4 is a sectional view of a main part of a heat fixing device according to another embodiment of the present invention. Note that, in the reference numerals used in the drawings, parts having the same functions as those in FIG. 3 are denoted by the same reference numerals. Further, points different from the first embodiment will be described.

The electrode members 39A, 39B of this embodiment
Has a concave shape, and a concave portion 3 near the center of the rotation axis.
9A ₂ and 39B ₂ are fitted to the leading end portions 42A ₂ and 42B ₂ of the power supply brushes 42A and 42B to be in sliding contact with each other. Inside the heat roller 31 near both ends in the axial direction, disk-shaped electrode members 39A and 39B are fixed and integrated. At the center of rotation of the electrode member 39A, a cylindrical bottomed concave portion 39A is provided.
_2, the rotation center of the electrode member 39B recess 39B ₂ with a cylindrical bottom, are respectively bored. The central axes of the recesses 39A ₂ and 39B ₂ are arranged coaxially with the central axis of rotation of the heat roller 31.

The outer peripheral surfaces near both ends in the axial direction of the heat roller 31 are rotatably supported by heat-insulating bearing members (hereinafter, referred to as bearings) 41A, 41B fixed to the side plates 40A, 40B.

The concave portion 39A ₂ of the electrode member 39A on the left side in the drawing.
The distal end portion 42A ₂ of the power supply brush 42A is fitted rotatably. The cover member 44B and a pressing spring 45A interposed in the interior of the holder 43B is to press the power supply brushes 42A, is crimped to the bottom of the recess 39A ₂ of the electrode member 39A. In the crimping state, the inner surfaces of the recess portion 39A ₂ is rotatably sliding contact with the outer peripheral surface of the distal end portion 42A ₂ of the power supply brush 42A.

The concave portion 39B ₂ of the electrode member 39B on the right side in the figure.
The distal end portion 42B ₂ of the power supply brush 42B is fitted rotatably. The cover member 44B and a pressing spring 45B interposed inside the holder 43B is to press the power supply brushes 42B, is crimped to the bottom of the recess 39B ₂ of the electrode member 39B. In the crimping state, the inner wall surface of the recess 39B ₂ is rotatably sliding contact with the outer peripheral surface of the distal end portion 42B ₂ of the power supply brush 42B.

In the second embodiment, the electrode member 39
A, 39B and the power supply brushes 42A, 42B
By arranging at the center of rotation of one, at least the center of the heat roller 31 comes into contact, and contacts at a place where the sliding speed is low,
In addition, the leading ends of the power supply brushes 42A and 42B are
Since the entire surface of the nine recesses 39A ₂ and 39B ₂ makes contact, the contact area can be increased, and stable power supply can be performed.

Also, the power supply brushes 42A, 42B are brought into contact with the rotation centers of the electrode members 39A, 39B, which are hardly affected by the mounting accuracy of parts such as runout and surface condition, so that the electrode members 39A, 39B and the power supply brush can be rotated even in the rotating state. 42A,
The contact between 42B can be stably maintained.

In order to supply a current exceeding several amperes to the heating resistor layer 314, the contact area between the electrode members 39A, 39B and the power supply brushes 42A, 42B is made as large as possible, and the current density per unit area is made low. It is possible to suppress.

Furthermore, the cross-sectional shape of the power supply brushes 42A and 42B is smaller when the electrode members 39A and 39B and the power supply brushes 42A and 42B are brought into three-dimensional contact than when they are brought into two-dimensional contact with each other on a flat surface. However, the contact area can be widened, and the movement of the side surface (peripheral surface) is regulated, so that a stable contact state can be obtained.

(Third Embodiment) FIG. 5 is a cross-sectional view of a principal part of a heat fixing device according to still another embodiment of the present invention.

The electrode members 39A, 39B of this embodiment
The concave portions 39A ₃ and 39B ₃ are formed such that a chamfer or an R chamfer is formed at the entrance of the inner surface (contact surface) formed of the cylindrical surface shown in the first embodiment. Or power supply brush 4
A small chamfer or a round chamfer may be formed at each of the distal ends 42A ₃ and 42B ₃ of the 2A and 42B.

By forming such a chamfer or round chamfer, the electrode member 39 can be replaced when the heat roller 31 is replaced.
A, the power supply brush 42 is provided in the concave portions 39A ₃ and 39B ₃ of the 39B.
When inserting the distal end portions 42A ₃ , 42B ₃ of the A, 42B, the work can be easily and surely performed without causing the power supply brushes 42A, 42B to be dropped, caught, or damaged.

(Fourth Embodiment) FIG. 6 is a sectional view of a main part of a heat fixing device according to still another embodiment of the present invention. Note that, in the reference numerals used in the drawings, parts having the same functions as those in the above-described embodiment are denoted by the same reference numerals. Further, points different from the above embodiment will be described.

The electrode members 39A, 39B of this embodiment
Recesses 39A _4, 39B ₄ of is formed by the inner surface (contact surface) comprising a conical surface and the cylindrical surface. Power supply brush 42
A, 42B, each tip 42A ₄ , 42B ₄
9A _4, 39B ₄ and formed on the outer surface of the conical surface and the cylindrical surface of the same shape, the electrode member 39A, 39B recess 39A ₄ of, 39B ₄
And is in sliding contact with it rotatably. In this embodiment, the electrode members 39A, 39B and the power supply brushes 42A, 4
Since the contact area of 2B is large, it is possible to keep the current density per unit area of the contact surface low.

(Fifth Embodiment) FIG. 7A is a sectional view of a main part of a heat fixing device according to a fifth embodiment of the present invention, and FIG. 7B is a partially enlarged cross section of the heat fixing device. FIG.

The electrode members 39A, 39B of this embodiment
3 has a convex shape as shown in FIG. 3, and a flat portion near the center of the rotation axis is in sliding contact with the distal ends of the power supply brushes 42A and 42B.

In this embodiment, the inner end faces of the electrode members 39A and 39B fixed inside the heat roller 31 are connected to at least the bearings 41A and 41B or the side plates (support members) 4A.
The heating fixing device is characterized in that the temperature rise of the bearings 41A, 41B or the side plates 40A, 40B is reduced by disposing them inside the installation positions of 0A, 40B.

In FIG. 7A, A 'and B' indicate that the electrode members 39A and 39B are formed by the heat generating resistance layer 314 of the heat roller 31.
And A and B represent electrode members 39.
Reference numerals A and 39B denote the inner end surfaces of the heat roller 31 that contact the heat generating resistance layer 314. L1 is a distance between the inner end surfaces A and B, a heating area of the heating resistance layer 314, and L2 is a bearing 41.
A, the distance between 41B, L3 is the side plate (support member) 40A,
40B. Here, the distances L2 and L3 are set slightly wider than the maximum width of the transfer material P passing through the heat roller 31. In the present invention, the electrode members 39A, 39B
The distance L1 between −B was set at a position such that L2> L1 and L3> L1.

In FIG. 7B, in the contact area AA 'between the electrode member 39A and the heating resistor layer 314, a larger amount of current is concentrated near the end face A than the end face A', and the shortest distance A
Only the area between -B is the heat generation area.

The heat generating resistance layer 314 is applied to the electrode members 39A and 39B provided at both ends in the axial direction of the inner surface type heat roller 31.
The current flowing through is concentrated on the low resistance part. That is, the current passing through the shortest distance (shown by a broken line) between the inner end surface A of the electrode member 39A and the contact surface between the power supply brush 42A and the electrode member 39A is the shortest distance portion between the electrode members 39A and 39B, that is, the inner end surface. The heat flows in the heat-generating resistor layer 314 between A and B, and the heat-generating resistor layer 314 generates heat.

According to the present invention, the electrode members 39A provided on both ends are provided.
The inner end faces A, B of the 39B are at least bearings 41A, 41
By arranging B or the inside of the side plates 40A, 40B, it is possible to reduce the temperature rise of the bearings 41A, 41B or the side plates 40A, 40B such as resin sliding bearings.

(Sixth Embodiment) FIG. 8A is a sectional view of a main part of a heat fixing device according to a sixth embodiment of the present invention.

The contact portions between the disk-shaped electrode member 39A and the power supply brush 42A and the contact portions between the electrode member 39B and the power supply brush 42B provided at both ends of the inner surface type heat roller 31 in the axial direction are provided. , A current of several amps is turned on and off, the contact resistance increases, and the power supply brushes 42A, 42B
When the contact becomes non-contact due to the pressing operation failure, electric discharge occurs at the contact portion, resulting in electrical noise. Therefore, by grounding the conductive base 312 of the heat roller 31, electric noise emitted to the outside of the heat fixing device is reduced.

Alternatively, as shown in a partially enlarged sectional view of FIG. 8B, the cover member 44A is formed of a conductive metal or a material coated with a conductive film, and this is grounded.

(Seventh Embodiment) FIG. 9 is a sectional view of a main part of a heat fixing device according to a sixth embodiment of the present invention.

In the heat fixing device of this embodiment, the outside of the outer peripheral surface of the heat insulating holder 43A is surrounded by the cylindrical conductive member 48A, and the outside of the outer peripheral surface of the heat insulating holder 43B is cylindrical. By covering the conductive members 48A and 48B with the grounding member 48B and grounding the conductive members 48A and 48B, electrical noise emitted to the outside of the heat fixing device is prevented.

(Eighth Embodiment) FIG. 10A is a sectional view of a main part of a heat fixing device according to a ninth embodiment of the present invention, and FIG. 10B is a partially enlarged cross section of the heat fixing device. FIG.

In the case of the inner surface type heat roller, the cylindrical electrode members 39A and 39B are attached by press-fitting, bonding or the like, but the conductive base (aluminum, iron, etc.) 312 and the electrode members (phosphor bronze, carbon, etc.) In general, the materials are different between 39A and 39B.

In the case of press-fitting, the accuracy of the outer diameter of the heat roller 31 is deteriorated, which affects the difference in fixing property, paper wrinkles, and the like. The electrode members 39A and 39B and the power supply brush 4
There is a disadvantage that the contact state with 2A and 42B becomes unstable.
If the press-fitting is too tight, the heating resistance layer 314 may be damaged or the outer shape may be deformed. If this press-fitting is loose, the power supply brushes 42A and 42B that are biased by springs are pressed inward from both ends in the axial direction, and the electrode member 39 is pressed.
A and 39B move inward, causing poor contact.

In the case of bonding, since the operating temperature of the heat roller 31 is about 200 ° C., there is a case where the adhesive peels off due to the difference in thermal expansion due to the constituent materials and the pressing force in the axial direction. .

In this embodiment, the electrode members 39A, 3
The flange portion 39A _5, 39B ₅ provided respectively 9B. The electrode members 39A and 39B are inserted and fitted into the main body of the heat roller 31, and the end surfaces of the flange portions 39A ₅ and 39B ₅ are abutted against both end surfaces in the axial direction of the heat roller 31 and fixed with a conductive adhesive or the like. did. The flange portion 39A _5, 3
By providing 9B _5, the electrode member 39A, 39B
However, even if they are pressed from both ends in the axial direction by the spring-biased power supply brushes 42A and 42B, they do not move in the axial direction and become stable.

As shown in FIG. 10B, an insulating layer 313 and a heating resistor layer 314 are also formed on both end faces in the axial direction of the heat roller 31 so that the end faces of the flange portions 39A ₅ and 39B ₅ are formed. The contact area was increased by contact. In addition, this end face abutting configuration is particularly suitable for a wall thickness of 1
mm or less.

(Ninth Embodiment) FIG. 11A is a sectional view of a main part of a heat fixing device according to a ninth embodiment of the present invention, and FIG. It is an expanded sectional view.

This embodiment is particularly suitable for a heat roller body having a thickness of 1 mm or more, and a step portion is provided on both end faces of the heat roller body between the outer diameter and the inner diameter, so that the axial direction can be reduced. The electrode members 39A and 39B were abutted.

The electrode members 39A, 39B are provided with flange portions 39A ₅ , 39B ₅ , respectively, and are formed with the flange portions 39A ₅ , 39B ₅ and the step portions 39A ₆ fitted to the step portions of the heat roller body. did. FIG.
As shown in (B), the insulating layer 313 and the heat generating resistance layer 314 were formed on both end surfaces in the axial direction of the heat roller 31 and also on the step portion.

The electrode members 39A and 39B are inserted and fitted into the main body of the heat roller 31, and the end surfaces of the flange portions 39A ₅ and 39B ₅ are brought into contact with both axial end surfaces of the heat roller 31. the stepped portion 39A ₆ abutted against the stepped portion of the heat roller 31, and fixed by such as a conductive adhesive. By providing the flange portions 39A ₅ and 39B ₅ , even if the electrode members 39A and 39B are pressed from both ends in the axial direction by the power supply brushes 42A and 42B which are biased by springs, they do not move in the axial direction and are stable. And at the same time, increase the conductive area. As shown in FIG.
Also both end surfaces in the axial direction of the heat roller 31 to form a heat generating resistor layer 314 and the insulating layer 313, the flange portion 39A _5, 39
By abutting the end face of the B _5, and so as to increase the conductivity area.

(Tenth Embodiment) FIG.
(B) is a sectional view of a main part of the heat fixing device according to the tenth embodiment of the present invention.

The electrode members 39A and 39B and the power supply brush 42
When the abrasion powder falls vertically below the contact portion with the A and 42B, the insulation distance of the power supply portion and the like is reduced, and a short circuit occurs.
In addition, when the abrasion powder falls and adheres to the release layer 311 on the surface of the heat roller 31, the release property is reduced. If the abrasion powder falls and adheres to a rotating part such as a bearing, there is a possibility that an increase in driving torque, locking or the like may occur.

According to the present invention, the abrasion powder receiving portion and the partition wall (rib) for preventing the abrasion powder from dropping are provided vertically below the contact portion between the electrode members 39A, 39B and the power supply brushes 42A, 42B.
49A and 49B were provided as a countermeasure against the above problem.

More specifically, a wear powder receiving portion and partition walls 49A and 49B for preventing falling wear powder from being diffused are provided on the cover member 44A, the fixing cover 300, and the like.

(Eleventh Embodiment) FIG. 13A is a sectional view of a main part of a heat fixing device according to an embodiment of the present invention, and FIG. 13 (C) and 13 (D) are perspective views of the power supply brush holding unit.

The present invention relates to a power supply brush 42 made of carbon or the like.
A, 42B, resin-made insulating holders 43A, 43B
When used as a guide member by making direct contact with each other, a pressing operation failure due to thermal deformation, accuracy and the like of the insulating holders 43A and 43B occurs. Therefore, the insulating holder 4
Metal guide members 51A and 51 are provided inside 3A and 43B.
B is newly provided to guide the power supply brushes 42A and 42B, thereby avoiding problems due to thermal deformation, poor accuracy, and the like, and smoothly and stably pressing the power supply brushes 42A and 42B. Can be done. At the same time, since the guide members 51A and 51B are made of metal,
The connecting portions of the lead wires 46A, 46B connected to the 2A, 42B and the connecting portions of the power supply terminals 47A, 47B, which are power connectors, can be provided integrally, and can be shared, thereby reducing the number of parts.

[0084]

The effects of the heat fixing device of the present invention are listed below.

(1) By arranging the heat generating roller, the electrode, and the triboelectric brush on concentric circles, at least the center of rotation is maintained in a stable contact state, that is, an electrically good conduction state. A more stable and electrically conductive state is maintained, and the current density per unit area of the contact portion can be reduced. (Claims 1 to 4) (2) By arranging the heat generating portion inside the bearing or the side plate (supporting portion), deterioration of bearings such as resin sliding bearings, side plates, etc., torque increase, deformation, breakage. Etc. can be prevented. (Claim 5) (3) The contact portion between the electrode member and the power supply brush is covered with a conductive metal on the base of the heat roller and the outside of the holder, and is grounded, so that electric noise is emitted outside the heat fixing device. To prevent. (Claims 6 to 8) (4) The electrode member and the heat roller are attached to the roller end face by pressing against the roller end face instead of press-fitting and bonding. The electrode member can be prevented from falling off. (Claim 9) (5) In addition to preventing a decrease in insulation distance and a short circuit due to a fall of abrasion powder from a contact portion between the electrode member and the power supply brush, a decrease in releasability when adhered to a heat roller surface. It is useful for prevention, increase of driving torque, prevention of lock, etc. when adhered to a rotating part such as a bearing, and prevention of dirt inside the apparatus around the fixing power supply part. (Claim 10) (6) Anxiety about thermal deformation and accuracy of the resin-made insulating holder is eliminated, and there is no thermal deformation and poor accuracy of the metal guide member. The guide member also serves as a lead wire of the power supply brush and a connection portion of the power connector, thereby reducing the number of components. (Claim 11
~ 13)

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of an image forming unit of an image forming apparatus according to the present invention.

FIG. 2 is a side sectional view and a front sectional view of a heat roller.

FIG. 3 is a sectional view of a main part of the heat fixing device according to the first embodiment.

FIG. 4 is a sectional view of a main part of a heat fixing device according to a second embodiment.

FIG. 5 is a sectional view of a main part of a heat fixing device according to a third embodiment.

FIG. 6 is a sectional view of a main part of a heat fixing device according to a fourth embodiment.

FIG. 7 is a sectional view of a main part and a partially enlarged sectional view of a heat fixing device according to a fifth embodiment.

FIG. 8 is a sectional view of a main part and a partially enlarged sectional view of a heat fixing device according to a sixth embodiment.

FIG. 9 is a sectional view of a main part of a heat fixing device according to a seventh embodiment.

FIG. 10 is a cross-sectional view of a main part and a partially enlarged cross-sectional view of a heat fixing device according to an eighth embodiment.

FIGS. 11A and 11B are a main part sectional view and a partially enlarged sectional view of a heat fixing device according to a ninth embodiment; FIGS.

FIG. 12 is a sectional view of a main part of a heat fixing device according to a tenth embodiment.

FIG. 13 is a sectional view, a partial sectional view, and a perspective view of a main part of a heat fixing device according to an eleventh embodiment.

FIG. 14 is a sectional view of a conventional heat fixing device.

[Explanation of symbols]

 Reference Signs List 30 heat fixing device 31 heat roller (internal heat generating roller) 311 release layer 312 base (core metal) 313 insulating layer 314 heat generating resistance layer 39A, 39B electrode member 40A, 40B side plate (support member) 41A, 41B bearing member ( Bearings 42A, 42B Power supply brushes 43A, 43B Holders 44A, 44B Cover members 45A, 45B Press springs 46A, 46B Lead wires 47A, 47B Power supply terminals 48A, 48B Conductive members 49A, 49B Partition walls (ribs) 50 Gears 51A, 51B Guide member

Claims (13)

[Claims] An unfixed developer image formed on the surface of a recording paper is passed by passing the recording paper through a pressure contact position between a heat roller that is driven to rotate and a pressure roller that is pressed against the heat roller and rotated. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member provided inside the vicinity of both ends in the roller axis direction and electrically connected to the heating resistance layer, and a conductive power supply brush that slides on the electrode member to supply power. A heat fixing device, wherein the heat roller, the electrode member, and the power supply brush are arranged concentrically. 2. The heat fixing device according to claim 1, wherein a concave portion is formed at the center of rotation of the electrode member, and a tip end of the power supply brush is slidably contacted with the concave portion. 3. The bottom and side surfaces of the concave portion of the electrode member,
2. The heat fixing device according to claim 1, wherein a sliding contact area is increased by slidingly contacting a front end portion and a side surface of the power supply brush. 3. 4. The heat fixing device according to claim 1, wherein the electrode member is pressed toward a rotation center of the electrode member urged by a spring. 5. An unfixed developer image formed on the surface of the recording paper is passed by passing the recording paper through a pressure contact position between a driving heat-rotating heat roller and a pressure roller rotating against the heat roller. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member is provided inside near both ends in the roller axis direction and is electrically connected to the heating resistance layer. Near both ends of the heat roller is a support member of the heat fixing device. A heat fixing device supported by a fixed bearing member, wherein an inner end surface of the electrode member fixed inside the heat roller is disposed at least inside an installation position of the bearing member or the support member; . 6. An unfixed developer image formed on the surface of a recording paper is passed by passing the recording paper through a pressure contact position between a heat roller that is driven to rotate and a pressure roller that is pressed against and rotates against the heat roller. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member that is provided inward near both ends in the roller axis direction and is electrically connected to the heating resistance layer, a conductive power supply brush that slides on the electrode member to supply power, A holder for holding the power supply brush, further comprising a shield member that covers the vicinity of a sliding contact portion between the electrode member provided near both ends of the rotating heat roller and the power supply brush fixedly arranged, and the shield member. Provide grounding means for grounding A heat fixing device for reducing electric noise emitted from the vicinity of the sliding contact portion to the outside of the heat fixing device. 7. The heat fixing device according to claim 6, wherein the grounded shield member is a conductive cover member that covers a holder that holds the power supply brush. 8. The heat fixing device according to claim 6, wherein the grounded shield member is a hollow conductive member that covers the vicinity of the sliding contact portion. 9. An unfixed developer image formed on the surface of a recording paper is passed by passing the recording paper through a pressure contact position between a driving heat-rotating heat roller and a pressure roller rotating against the heat roller. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member provided inward near both ends in the roller axis direction and electrically connected to the heat generating resistance layer; and supplying power by pressing the electrode member and the heat roller in a rotation axis direction of the heat roller. And a conductive power supply brush, wherein the power supply brush includes a cylindrical portion fitted to an inner cylindrical surface of the heat roller, and a flange portion axially abutting an end surface of the heat roller. Fixing device. 10. An unfixed developer image formed on the surface of a recording paper is passed by passing the recording paper through a pressure contact position between a heat roller that is driven and rotated and a pressure roller that is pressed against the heat roller and rotated. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member provided inward near both ends in the roller axis direction and electrically connected to the heat generating resistance layer; and supplying power by pressing the electrode member and the heat roller in a rotation axis direction of the heat roller. A conductive power supply brush, a holder for holding the power supply brush, and a cover member for covering the outside of the power supply brush, further comprising a slide between the power supply brush and the electrode member on the inner surface side of the holder. A partition wall below the contact A heating chamber provided with a chamber, wherein abrasion powder generated and dropped by frictional contact between the electrode member and the power supply brush is accommodated in the partition chamber. 11. An unfixed developer image formed on a surface of a recording paper is passed by passing the recording paper through a pressure contact position between a heat roller that is driven to rotate and a pressure roller that is pressed against the heat roller and rotated. In the heat fixing device for performing heat fixing, the heat roller is an inner surface type heat roller having a heat generating resistance layer via an insulating layer on an inner surface of a cylindrical cored bar, and the heat fixing device includes a heat roller. A disk-shaped electrode member provided inward near both ends in the roller axis direction and electrically connected to the heat generating resistance layer; and supplying power by pressing the electrode member and the heat roller in a rotation axis direction of the heat roller. A heat fixing device comprising: a conductive power supply brush; a conductive guide member that holds the power supply brush so as to be movable in a rotation axis direction; and an insulating holder that fixes and holds the guide member. 12. The conductive guide member according to claim 11, wherein a part for locking one end of a lead wire connected to the movable power supply brush is formed integrally with a part of the conductive guide member. Heat fixing device. 13. The heat fixing device according to claim 11, wherein a power supply terminal portion connected to a power supply for the heat fixing device is formed integrally with a part of the conductive guide member.