JP2014063007A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device having a ground electrode for earthing a pressure member stably.SOLUTION: A fixing device 100 configured to be mounted on a body housing 10 (body) of a color printer 1 (image forming device) includes a heating roller 110, a pressure roller 120, a frame 101 for supporting the heating roller 110, a pair of metal swing arms 130 rotatably supported for the frame 101 and supporting each of ends of the pressure roller 120, a pair of springs 135 interposed between the pair of swing arms 130 and the frame 101 to cause the pressure roller 120 to press the heating roller 110, and a ground electrode to be connected to a contact GEP provided in the body housing 10. The ground electrode includes a first ground electrode 160 with one end in elastic contact with an outer peripheral surface 132 of a rotary part 131 of the swing arms 130, and earths the pressure roller 120 via the first ground electrode 160.

Description

  The present invention relates to a fixing device including a ground electrode.

  In order to fix a recording sheet on which a developer image is formed, an image forming apparatus including a fixing device including a heating roller and a pressure roller pressed against the heating roller is known.

  In the fixing device, electric charge may be accumulated on the heating roller and the pressure roller by conveying the recording sheet. Since the charges accumulated on the heating roller and the pressure roller cause the developer image to deteriorate when discharged onto the recording sheet, it is necessary to ground them.

For example, Patent Document 1 discloses a fixing device including a heating roller and a pressure roller, and a pair of arms that rotatably support both ends of the pressure roller are supported by a frame so as to be swingable. The structure which presses a pressure roller to a heating roller by providing a tension coil spring between the front-end | tip part and a flame | frame is disclosed.
In such a fixing device, the pressure roller is grounded by contacting another grounded coil spring with a hook at the tip of the tension coil spring.

JP 2009-134130 A

  However, in the configuration disclosed in Patent Document 1, since the tension coil spring may move with the movement of the pressure roller, the contact between the hook of the tension coil spring and the coil spring is very unstable, and the pressure roller is grounded. There was a possibility that it could not be performed stably.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a fixing device including a ground electrode that can stably ground a pressure member such as a pressure roller.

In order to solve the above problems, a fixing device according to the present invention is configured to be attached to an image forming apparatus main body, and includes a heating member, a pressing member configured to be pressed against the heating member, A pair of metal arms each having a frame that supports the heating member, a rotation portion that is rotatably supported with respect to the frame, and supports each end of the pressure member; A pair of springs configured to be interposed between the arm and the frame so as to press the pressure member against the heating member, and a contact provided on the image forming apparatus main body. And a ground electrode configured.
The ground electrode includes a first ground electrode whose one end is elastically in contact with the outer peripheral surface of the rotating portion of one arm, and the pressure member is grounded via the first ground electrode. It is characterized by.

  According to such a configuration, since the one end portion of the first ground electrode that grounds the pressure member is in elastic contact with the outer peripheral surface of the rotation portion that is the rotation center of the arm, the rotation of the arm It is possible to reduce the change in the contact pressure due to the pressure, and the pressure member can be grounded stably.

  In the fixing device described above, it is preferable that the outer peripheral surface of the rotating portion that contacts the first ground electrode has an arc surface that extends concentrically with the rotation center of the rotating portion.

  According to this, the one end portion of the first ground electrode is in elastic contact with the outer peripheral surface which is an arc surface extending concentrically with the rotation center of the rotation portion, so that the contact pressure regardless of the rotation position of the arm. Can be made substantially constant, and the pressure member can be grounded more stably.

  In the fixing device described above, it is preferable that the ground electrode includes a second ground electrode that grounds the heating member, and the second ground electrode and the first ground electrode are connected.

  According to this, the second ground electrode for grounding the heating member and the first ground electrode for grounding the pressure member are connected to each other and connected to the contact provided on the main body of the image forming apparatus. A compact and simple configuration can be obtained.

  The fixing device described above further includes a temperature detection member provided to face the heating member, and the ground electrode includes a metal third ground electrode that grounds the temperature detection member, and the third ground electrode is It is preferable that the temperature detecting member is grounded via the first ground electrode by being connected to the first ground electrode.

  According to this, by connecting the third ground electrode for grounding the temperature detection member and the first ground electrode for grounding the pressure member, and connecting to the contact provided on the main body of the image forming apparatus, the ground electrode Can be made compact and simple.

  The fixing device described above further includes a nip pressure adjusting mechanism configured to adjust a nip pressure between the heating member and the pressure member, and the nip pressure adjusting mechanism includes the pair of arms. It is preferable that the rotation unit is configured to rotate about the rotation center.

  According to this, when the nip pressure between the heating member and the pressure member is adjusted by the nip pressure adjusting mechanism, the nip pressure is adjusted by turning the pair of arms around the turning portion of the arm. However, regardless of the nip pressure, the contact pressure between the first ground electrode and the arm can be made substantially constant, and the pressure member can be stably grounded.

  In the fixing device described above, the first ground electrode may be formed of a metal plate.

  According to this, the 1st earthing electrode can be easily manufactured by forming from a metal plate.

  According to the present invention, the one end portion of the first ground electrode that grounds the pressure member is in elastic contact with the outer peripheral surface of the rotating portion serving as the center of rotation of the arm, and thus is caused by the rotation of the arm. The change in contact pressure can be reduced, and the pressure member can be grounded stably.

1 is a cross-sectional view illustrating a schematic configuration of a color printer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device. FIG. 2 is a perspective view of the fixing device with a frame removed. A perspective view (a) of the first ground electrode and a perspective view (b) of the second ground electrode are shown. FIG. 3 is a cross-sectional perspective view of a fixing device showing a first ground electrode and a second ground electrode.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the direction will be described with reference to a user who uses the color printer 1 as an example of the image forming apparatus. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

<Schematic configuration of color printer>
As shown in FIG. 1, the color printer 1 mainly includes a paper feeding unit 20 and an image forming unit 30 in a main body housing 10 as an example of an apparatus main body. An upper cover 12 is provided on the upper side of the main body housing 10 so as to be opened and closed up and down with the rear side as a rotation center.

  The paper feeding unit 20 is provided in the lower part of the main body housing 10, and includes a paper feeding tray 21 that stores recording paper P as an example of a recording sheet, a paper pressing plate 22, a paper feeding roller 23, and a recording paper P Are mainly provided with a separation roller 25, a separation pad 26, a paper dust removing roller 27, and a registration roller 28 provided on the conveyance path 24. The recording paper P in the paper feed tray 21 is brought close to the paper feed roller 23 by the paper pressing plate 22 and sent out by the paper feed roller 23. The fed recording paper P is separated one by one by the separation roller 25 and the separation pad 26, and after a certain amount of paper dust is collected by the paper dust removing roller 27, it is supplied to the image forming unit 30 by the registration roller 28.

  The image forming unit 30 mainly includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing device 100.

  The LED unit 40 is disposed above the photosensitive drum 53 and includes a plurality of LEDs (light emitting diodes) (not shown) arranged in the left-right direction at the lower end thereof. The LED unit 40 exposes the surface of the photosensitive drum 53 by blinking the LED based on the image data. The LED unit 40 is held by the upper cover 12 and is separated from the photosensitive drum 53 by opening the upper cover 12.

  A plurality of process cartridges 50 are arranged side by side in the front-rear direction between the upper cover 12 and the paper feed tray 21, and are exchangeably mounted on the main body housing 10 in a state where the upper cover 12 is opened. It is the composition which becomes. Each process cartridge 50 includes a photoreceptor cartridge 51 and a developing cartridge 61 that is detachable from the photoreceptor cartridge 51.

  Each photoconductor cartridge 51 mainly includes a photoconductor drum 53, a charger 54, and a collection roller 55. The collection roller 55 is a roller for collecting the transfer residual toner attached on the photosensitive drum 53. Each of the developing cartridges 61 includes a developing roller 63, a supply roller 64, a layer thickness regulating blade 65, an agitator 66, and a container 67 that stores positively chargeable toner as an example of a developer. Is mainly configured.

  The transfer unit 70 is provided between the paper feed tray 21 and the process cartridge 50, and mainly includes a driving roller 71, a driven roller 72, an endless conveyance belt 73, and four transfer rollers 74. . The conveying belt 73 is stretched between the driving roller 71 and the driven roller 72, and is disposed to face the photosensitive drum 53 on which the outer surface is arranged. The transfer roller 74 corresponds to the inner side of the conveying belt 73. A conveying belt 73 is disposed between the photosensitive drum 53 and the photosensitive drum 53.

The fixing device 100 is provided behind the process cartridge 50 and the transfer unit 70 and mainly includes a heating roller 110 and a pressure roller 120 that is disposed to face the heating roller 110 and presses the heating roller 110.
Details of the fixing device 100 will be described later.

  In the image forming unit 30, the surface of the photosensitive drum 53 is uniformly positively charged by the charger 54 and then exposed by the LED unit 40, whereby the electrostatic latent image based on the image data is formed on the photosensitive drum 53. An image is formed. Further, the toner in the container 67 is supplied to the developing roller 63 to which the developing bias is applied via the supply roller 64 while being agitated by the agitator 66, and enters between the developing roller 63 and the layer thickness regulating blade 65. Then, it is carried on the developing roller 63 as a thin layer having a constant thickness. When the developing roller 63 comes into contact with the photosensitive drum 53, toner is supplied from the developing roller 63 to the photosensitive drum 53, whereby the electrostatic latent image is visualized and developed on the photosensitive drum 53. A toner image as an agent image is formed.

  Thereafter, the recording paper P supplied to the image forming unit 30 is conveyed between the photosensitive drum 53 and the conveying belt 73, so that the toner image formed on the photosensitive drum 53 is transferred onto the recording paper P. Is done.

The recording paper P to which the toner image has been transferred is conveyed to the fixing device 100, and the toner image is thermally fixed while passing between the heating roller 110 and the pressure roller 120, whereby an image is formed on the recording paper P. It is formed.
Thereafter, the recording paper P is transported along the paper discharge path 14 by the transport roller 90 and the discharge roller 95, passes through the discharge port 15 of the main body housing 10, and enters the discharge tray 13 from the inside of the main body housing 10. Discharged.

<Configuration of fixing device>
As shown in FIGS. 2 and 3, the fixing device 100 includes a frame 101, and a heating roller 110 as an example of a heating member and a pressure roller 120 as an example of a pressure member can rotate on the frame 101. It is supported by.
The heating roller 110 is supported by the frame 101 via a pair of left and right bearings 140. The pressure roller 120 is attached to the frame 101 via two left and right swing arms 130 which are an example of a pair of arms.

The frame 101 is made of an insulating resin and extends in the left-right direction (the width direction of the recording paper P) along the axial direction of the heating roller 110 and the pressure roller 120. As shown in FIG. 2, the frame 101 covers the heating roller 110 from above, and has an upper surface portion 101U, a front surface portion 101F, and a front surface inclined portion 101S.
A screw hole 108 and a positioning pin 109 for fixing a later-described ground electrode are formed on the left end of the upper surface portion 101U. A screw hole 106 and a positioning pin 107 for attaching a fixing frame 145 described later are formed in the front surface portion 101F.
Further, below the front surface portion 101F, a support shaft portion 102 that rotatably supports the swing arm 130 is formed.

A bearing fixing portion 103 to which the bearing 140 of the heating roller 110 is fixed is formed at the center of the lower surface of the frame 101. A hook portion 104 to which one end of a spring 135 to be described later is fixed is formed on the upper rear side of the frame 101.
The support shaft portion 102, the bearing fixing portion 103, the hook portion 104, the hole 106, and the positioning pin 107 are provided symmetrically at the left and right end portions of the fixing device 100, but only one side (left side) in FIG. Indicates.

The heating roller 110 is formed of a cylindrical metal tube having a halogen heater 115 inside. The heating roller 110 is rotatably supported by the frame 101 through the bearings 140 at the rotating shaft portions 112 at both ends.
As shown in FIG. 3, a thermistor 143 as an example of a temperature detection member is provided at the center of the heating roller 110 so as to face the heating roller 110. The thermistor 143 is disposed inside the frame 101 and spaced from the surface of the heating roller 110.
The thermistor 143 is fixed to a metal fixing frame 145 constituting a third ground electrode described later with screws 144.

The bearing 140 that rotatably supports the heating roller 110 is made of a conductive resin. The bearing 140 rotatably supports cylindrical rotating shaft portions 112 provided at both ends of the heating roller 110.
As shown in FIG. 3, the bearing 140 is obtained by connecting two plate members 141 to each other at a plurality of locations in the circumferential direction, and a connection rib 142 located at the upper end has a second ground electrode described later. One end of 170 contacts elastically.

The pressure roller 120 is configured by covering the periphery of a cored bar 122 (see FIG. 1) provided at the center with urethane rubber or the like. In the pressure roller 120, both ends of the cored bar 122 protrude outward, and the protruding both ends are rotatably supported by the swing arm 130 via a bearing 125.
As shown in FIGS. 2 and 3, the bearing 125 is made of a conductive resin, and is fixed to the central portion of the swing arm 130.

The oscillating arm 130 is a substantially L-shaped member made of a steel plate in a side view.
As shown in FIG. 2 and FIG. 3, the swing arm 130 is formed with a rotating portion 131 that is rotatably supported with respect to the support shaft portion 102 at one end. The outer peripheral surface 132 of the rotation part 131 forms an arcuate surface that extends concentrically with the rotation center RC of the rotation part 131.
The swing arm 130 has a hook portion 133 at the other end opposite to the end where the rotation portion 131 is formed, with a central portion to which the bearing 125 is fixed.
A support shaft member 134 that rotatably supports an operation lever 152 of a nip pressure adjusting mechanism 150 described later is fixed to the other end where the hook portion 133 is formed.

  The hook portion 133 of the swing arm 130 is disposed at a position facing the hook portion 104 of the frame 101, and a spring 135 is interposed therebetween. One end 136 of the spring 135 is engaged with the hook portion 133 of the swing arm 130 and the other end 137 is engaged with the hook portion 104 of the frame 101, so that the spring 135 always functions as a tension spring. Then, it is biased upward about the rotating part 131. Due to the tensile force of the spring 135, the pressure roller 120 is pressed against the heating roller 110 with a predetermined nip pressure.

As shown in FIGS. 2 and 3, the nip pressure adjusting mechanism 150 is provided in a pair of left and right in the width direction of the recording paper P, and can be rotated by a support shaft member 134 fixed to the other end of the swing arm 130. By operating the operation lever 152 that is pivotally supported, the nip pressure can be adjusted to a predetermined value. Since a known mechanism can be employed for the configuration for this purpose, a detailed description is omitted.
The nip pressure adjusting mechanism 150 includes, for example, a normal nip mode during normal printing, an envelope mode suitable for simultaneously transporting two sheets of paper, such as weak thin paper or an envelope, and a heating roller 110 and pressure. When a paper jam occurs with the roller 120, the nip pressure can be adjusted between the nip pressure release mode in which the nip pressure is released. At the time of this adjustment, the operation lever 152 moves the swing arm 130 up and down against the tensile force of the spring 135.

<Fixing device grounding circuit>
Next, the grounding circuit of the fixing device 100 will be described with reference to FIGS.
The heating roller 110 and the pressure roller 120 of the fixing device 100 are connected to a contact GEP (see FIG. 2) provided on the main body housing 10 of the color printer 1 via a ground electrode provided on the left end portion of the fixing device 100. Electrically connected.
Specifically, the ground electrode includes a first ground electrode 160 for grounding the pressure roller 120, a second ground electrode 170 for grounding the heating roller 110, and a third ground for grounding the thermistor 143. A fixed frame 145 that is an electrode is included.

As shown in FIG. 4A, the first ground electrode 160 is formed by bending a metal plate.
The first ground electrode 160 includes a first fixed base 163 disposed in contact with the upper surface 101U of the frame 101, a second fixed base 166 disposed in contact with the front surface 101F of the frame 101, and a first fixed. A bent inclined portion 167 connecting one end of the base portion 163 and one end of the second fixed base portion 166, extending along the front inclined portion 101S of the frame 101, and a leaf spring contact portion extending downward from the other end of the second fixed base portion 166 168. The leaf spring contact portion 168 has a distal end portion 169 bent so as not to damage each component of the fixing device 100 during assembly.
A through hole 161 and a pin insertion hole 162 are formed in the first fixed base 163 corresponding to the hole 108 and the positioning pin 109 (see FIG. 2) provided in the upper surface portion 101U of the frame 101.
In the second fixed base portion 166, a long through hole 164 and a pin insertion hole 165 are formed on the left and right, corresponding to the hole 106 and the positioning pin 107 provided in the front surface portion 101 </ b> F of the frame 101.
As shown in FIG. 2, the first ground electrode 160 configured as described above is assembled with the leaf spring contact portion 168 in a bent state, so that it is elastic with the outer peripheral surface 132 of the rotating portion 131 of the swing arm 130. To come into contact.

As shown in FIG. 4B, the second ground electrode 170 is formed by bending a metal plate in the same manner as the first ground electrode 160.
The second ground electrode 170 includes a first fixed base portion 173 that overlaps the first fixed base portion 163 of the first ground electrode 160, a contact portion 174 that extends diagonally forward from one end of the first fixed base portion 173, and a first And a leaf spring contact portion 175 extending downward from the other end of the fixed base portion 173.
A through hole 171 and a pin insertion hole 172 are formed in the first fixed base 173 corresponding to the through hole 161 and the pin insertion hole 162 of the first ground electrode 160.
As shown in FIG. 2, the second ground electrode 170 having such a configuration is such that the contact portion 174 is electrically connected to the contact GEP provided in the main body housing 10, and the leaf spring contact portion 175 is bent. By being assembled in a state, it comes into elastic contact with the connection rib 142 of the bearing 140 of the heating roller 110 (see FIG. 3).

  As shown in FIGS. 2 and 3, the fixed frame 145 as the third ground electrode is formed by bending a steel plate, and corresponds to the hole 106 and the positioning pin 107 provided in the front surface portion 101 </ b> F of the frame 101. The through hole 148 and the pin insertion hole 146 are formed in pairs on the left and right.

As shown in FIG. 5, each ground electrode configured as described above is formed on the left side of the frame 101 with the first ground electrode 160, the second ground electrode 170, and the fixed frame (third ground electrode) 145 overlapped. Fixed to the end.
Specifically, the first fixed base 163 of the first ground electrode 160 and the first fixed base 173 of the second ground electrode 170 are overlapped, and the positioning pins provided on the upper surface portion 101U of the frame 101 in the pin insertion holes 162 and 172. By inserting 109, the first ground electrode 160 and the second ground electrode 170 are temporarily fixed to the frame 101. At the same time, the left end portion of the fixed frame 145 and the second fixed base portion 166 of the first ground electrode 160 are overlapped, and the positioning pin 107 provided on the front surface portion 101F of the frame 101 is inserted into the pin insertion holes 146 and 165. The first ground electrode 160 and the fixed frame 145 are temporarily fixed to the frame 101. In this state, the through-hole 171 of the second ground electrode 170 and the through-hole 161 of the first ground electrode 160 coincide with the hole 108 provided in the frame 101, and the through-hole 164 of the first ground electrode 160 and the through-hole of the fixed frame 145 The hole 148 coincides with the hole 106 provided in the frame 101.
Thereafter, the screw 179 is passed through the through-hole 171 of the second ground electrode 170 and the through-hole 161 of the first ground electrode 160 from above, and the screw 179 is screwed into the screw hole 108 of the frame 101, whereby the first ground electrode 160 and the second ground electrode 170 are fastened to the frame 101 together. Similarly, a screw 149 is threaded through the through hole 164 of the first ground electrode 160 and the through hole 148 of the fixed frame 145 from the front, and the screw 149 is screwed into the screw hole 106 of the frame 101, whereby the first ground electrode 160. The fixing frame 145 is fastened to the frame 101 together.

  In addition, since the through hole 164 of the first ground electrode 160 is a long hole, even if there is a dimensional error in each part or the frame 101 or the fixed frame 145 expands or contracts to the left or right due to a temperature change, the first ground electrode 160. Can be attached.

  According to the ground electrode configured as described above, the metal core 122 of the pressure roller 120, the bearing 125 formed of conductive resin, and the swing arm 130 formed of steel plate are electrically connected, and The outer peripheral surface 132 of the rotating part 131 of the swing arm 130 is electrically connected to the leaf spring contact part 168 of the first ground electrode 160. Then, the first ground electrode 160 and the second ground electrode 170 are electrically connected, and the contact portion 174 of the second ground electrode 170 is a contact GEP provided in the main body housing 10 of the color printer 1 (see FIG. 2). The pressure roller 120 can be grounded through the main body housing 10.

  Further, the rotary shaft portion 112 of the heating roller 110 made of a metal tube and the bearing 140 made of conductive resin are electrically connected, and the connection rib 142 of the bearing 140 is connected to the leaf spring of the second ground electrode 170. It is electrically connected to the contact portion 175. The contact portion 174 of the second ground electrode 170 is electrically connected to a contact GEP (see FIG. 2) provided on the main body casing 10 of the color printer 1, so that heating is performed via the main body casing 10. The roller 110 can be grounded.

  Further, the thermistor 143 is electrically connected to a metal fixed frame 145 that is a third ground electrode, and the left end of the fixed frame 145 is electrically connected to the second fixed base 166 of the first ground electrode 160. Is done. Then, the first ground electrode 160 and the second ground electrode 170 are electrically connected, and the contact portion 174 of the second ground electrode 170 is a contact GEP provided in the main body housing 10 of the color printer 1 (see FIG. 2). The thermistor 143 can be grounded via the main body housing 10.

According to the above, the following effects can be obtained in the present embodiment.
One end portion (leaf spring contact portion 168) of the first ground electrode 160 that grounds the pressure roller 120 is elastically in contact with the outer peripheral surface 132 of the rotation portion 131 that is the rotation center of the swing arm 130. Therefore, it is possible to reduce a change in contact pressure due to the rotation of the swing arm 130, and the pressure roller 120 can be stably grounded.

  One end portion (leaf spring contact portion 168) of the first ground electrode 160 is in elastic contact with the outer peripheral surface 132 that is a circular arc surface extending concentrically with the rotation center RC of the rotation portion 131. Regardless of the rotational position, the contact pressure can be made substantially constant, and the pressure roller 120 can be grounded more stably.

  By connecting the second ground electrode 170 for grounding the heating roller 110 and the first ground electrode 160 for grounding the pressure roller 120, the second ground electrode 170 is connected to the contact GEP provided in the main body housing 10 of the color printer 1. The ground electrode can have a compact and simple configuration.

  A third ground electrode (fixed frame 145) for grounding the thermistor 143 and a first ground electrode 160 for grounding the pressure roller 120 are connected to a contact GEP provided on the main body housing 10 of the color printer 1. By doing so, the ground electrode can be made compact and simple.

  Since the pair of left and right nip pressure adjusting mechanisms 150 are configured to rotate the pair of swing arms 130 around the swing portion 131 of each swing arm 130, the nip pressure adjusting mechanism 150 causes the heating roller to rotate. 110 and the pressure roller 120 can be adjusted, and the contact pressure between the first ground electrode 160 and the swing arm 130 can be made substantially constant regardless of the nip pressure. The pressure roller 120 can be stably grounded.

  By forming the first ground electrode 160 from a metal plate, the first ground electrode 160 can be easily manufactured.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

In the embodiment, the fixing device 100 including the heating roller 110 and the pressure roller 120 has been described as an example. For example, a fixing roller is provided in addition to the heating roller, and an endless belt is stretched between them. A heating member can also be comprised. In this case, the second ground electrode can be electrically connected to the conductive member at one or both ends of the heating roller and / or the fixing roller.
It is also possible to configure a film-type heating member that rotationally drives an endless fixing film around the heating member. In this case, the second ground electrode can be electrically connected to a conductive member that covers the periphery of the heating member.
Further, the pressure member pressed by the heating member is not necessarily a rotatable roller, and may be a non-rotating type pressure member fixed to a pair of rotatable arms.

DESCRIPTION OF SYMBOLS 1 Color printer 10 Main body housing | casing 100 Fixing apparatus 101 Frame 110 Heating roller 120 Pressure roller 130 Oscillating arm 131 Rotating part 132 Outer peripheral surface 135 Spring GEP Contact RC Rotation center 143 Thermistor 145 Fixed frame (third ground electrode)
150 Nip pressure adjusting mechanism 160 First ground electrode 168 Leaf spring contact portion 170 Second ground electrode

Claims (6)

A fixing device configured to be attached to an image forming apparatus main body,
A heating member;
A pressure member configured to be pressed against the heating member;
A frame that supports the heating member;
A pair of metal arms each having a rotating portion supported rotatably with respect to the frame and supporting each end of the pressure member;
A pair of springs interposed between the pair of arms and the frame and configured to press the pressure member against the heating member;
A ground electrode configured to be connected to a contact provided in the image forming apparatus main body,
The ground electrode includes a first ground electrode whose one end is elastically in contact with the outer peripheral surface of the rotating portion of one arm, and grounds the pressure member via the first ground electrode. A fixing device.   2. The fixing device according to claim 1, wherein an outer peripheral surface of the rotating portion that contacts the first ground electrode has an arc surface extending concentrically with a rotation center of the rotating portion.   The fixing according to claim 1, wherein the ground electrode includes a second ground electrode that grounds the heating member, and the second ground electrode and the first ground electrode are connected to each other. apparatus. A temperature detection member provided opposite to the heating member;
The ground electrode includes a metal third ground electrode for grounding the temperature detection member, and the third ground electrode is connected to the first ground electrode so that the temperature detection member is connected to the first ground electrode. 4. The fixing device according to claim 1, wherein the fixing device is configured to be grounded through the fixing device. 5. A nip pressure adjusting mechanism configured to adjust a nip pressure between the heating member and the pressure member;
5. The nip pressure adjusting mechanism is configured to rotate the pair of arms around a rotation portion of each arm as a rotation center. 6. The fixing device described. The fixing device according to claim 1, wherein the first ground electrode is formed of a metal plate.

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