JP2004279716A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fix an accurate image with a heat pressure type fixing device by attracting a developer toward a form. <P>SOLUTION: The rotary shaft 104 of a pressure roll 76 is grounded through one 1st bearing 114, a bracket 84, and a grounding terminal member 116. As for the coating layer 108 of the pressure roll 76, a bias voltage source 112 is connected to an end surface on the side of the ungrounded bracket 84 through a terminal member 110 for electrification, and electric charges having the opposite polarity from the developer are supplied. The bias power source 112 is connected to an inlet chute 90 through the terminal member 110 for electrification, and electric charges having the opposite polarity from the developer are supplied. As for a heat roll 74, a 2nd bearing 118 positioned in the vicinity of the grounded bracket 84 is grounded through a grounding terminal member 116 equipped with a rectifier 102, and a core 98 holds electric charges having the same polarity with the developer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing device and an image forming apparatus having the same.
[0002]
[Prior art]
2. Description of the Related Art As a fixing device of an image forming apparatus, a heat-pressure type fixing device having a pair of rotating members pressed against each other is well known. In this type of fixing device, a so-called offset that the developer transferred to the sheet is not completely fixed to the sheet but adheres to the surface of the heating roll may occur. In order to prevent this offset, the heating roll holds an electric charge of the same polarity as the toner, and the angle between the direction in which the paper is separated from the transfer roll and the tangent to the image carrier at the nip center is on the image carrier side. It is known to provide a guide for guiding a sheet so as to be at least twice (see Patent Document 1).
Further, when a negative toner and a positive toner are used, respectively, the opposite polarity potentials of the respective toners are switched and applied to the heating roller (see Patent Document 2), and interlocked with the change in the charge removal amount by the corona discharger. Changing the intensity of the electric field applied to the heating roll (see Patent Document 3), and maintaining the potentials of the heating roll and the pressure roll, respectively, and adjusting the surface potential of the pressure roll with the powder of silicon dioxide. It is known from Patent Document 4 to prevent offset.
[0003]
[Patent Document 1] JP-A-5-6113
[Patent Document 2] JP-A-7-129006
[Patent Document 3] JP-A-7-175356
[Patent Document 4] JP-A-62-242979
[0004]
[Problems to be solved by the invention]
However, before the sheet is conveyed to the pair of rotating bodies pressed against each other of the fixing device, the potential for attracting the developer to the sheet side is insufficient due to the potential of a member located near the pair of rotating bodies, or the like. May become unstable.
Accordingly, an object of the present invention is to provide a fixing device capable of stably fixing an image and an image forming apparatus having the fixing device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a feature of the present invention is that a heating roll having a conductive core and an insulating release layer coated on the surface side of the core is pressed against the heating roll. A pressure roll provided with a conductive coating layer on the surface, a conveyance guide provided near the pressure roll and guiding a sheet between the heating roll and the pressure roll, and the pressure roll A fixing unit having a first power supply unit for applying a bias voltage to the cover layer, a second power supply unit for applying a bias voltage to the conveyance guide, and a grounding unit for grounding the core via a rectifier. .
[0007] The first power supply means and the second power supply means supply power so that a bias voltage having a polarity opposite to the polarity of the developer is applied, and the rectifier has the same polarity as the polarity of the developer. It is preferable that the connection is made in such a direction that electric charges are held in the core.
Further, it is preferable that the first power supply means includes a terminal member having a contact portion that comes into contact with the coating layer of the pressure roll, and the contact portion is preferably formed in a curved shape.
[0009] The first power supply means and the second power supply means may include a first contact portion that contacts a coating layer of the pressure roll, and a second contact portion that contacts the transport guide. Preferably has a terminal member integrally formed.
[0010] Further, it is preferable that the first power supply means and the second power supply means are provided so as to be separated from the grounding means.
Further, it is preferable that the second power supply means has a terminal member that contacts the transport guide to supply power and that fixes the transport guide.
According to a second feature of the present invention, there is provided an image forming apparatus having the above-described fixing device.
According to a third feature of the present invention, the fixing device is unitized so as to be detachable from an apparatus main body, and the apparatus main body includes the first and second power supply means and the ground. The image forming apparatus according to the above, further comprising a receiving unit for receiving the unit so as to be electrically connected to the apparatus main body in synchronization with the mounting of the fixing unit.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 has an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a discharge unit 16 described later is provided above the image forming apparatus main body 12. At the same time, for example, two-stage paper feed units 18 are arranged below the image forming apparatus main body 12. Further, a plurality of paper feed units can be optionally arranged below the image forming apparatus main body 12.
Each paper supply unit 18 has a paper supply unit main body 20 and a paper supply cassette 22 for storing paper. A pickup roll 24 is disposed in the upper portion near the back end of the sheet cassette 22, and a retard roll 26 and a feed roll 28 are disposed behind the pickup roll 24.
The main transport path 32 is a paper path from the feed roll 28 to the discharge port 34. The main transport path 32 is located near the back side (left side in FIG. 1) of the main body 12 of the image forming apparatus. It has a portion that is formed substantially vertically from the paper feed unit 18 at the lower end to a fixing device 36 described later. A transfer device 42 and an image carrier 44, which will be described later, are arranged upstream of the fixing device 36 in the main transport path 32, and a registration roll 38 is arranged upstream of the transfer device 42 and the image carrier 44. Further, a discharge roll 40 is disposed near the discharge port 34 of the main transport path 32.
Accordingly, the paper fed from the paper feed cassette 22 of the paper feed unit 18 by the pickup roll 24 is separated by the cooperation of the retard roll 26 and the feed roll 28, and only the uppermost paper is guided to the main transport path 32. Then, the developer image is temporarily stopped by the registration roll 38, and the developer image is transferred at a time between the transfer device 42 and the image carrier 44, which will be described later, and the transferred developer image is fixed by the fixing device 36. Then, the sheet is discharged from the discharge port 34 to the discharge section 16 by the discharge roll 40.
However, in the case of double-sided printing, it is returned to the reversing path. That is, the main transport path 32 is branched into two parts before the discharge roll 40, a switching device 46 is provided in the divided part, and a reversing path 48 that returns from the divided part to the registration roll 38 is formed. . The reversing path 48 is provided with transport rolls 50a to 50c. In the case of double-sided printing, the switching device 46 is switched to the side where the reversing path 48 is opened, and the time when the trailing end of the sheet is applied to the discharge roll 40 is reached. Then, the discharge roll 40 is reversed, and the sheet is guided to the reversing path 48, and is discharged from the discharge port 34 to the discharge unit 16 through the registration roll 38, the transfer device 42, the image carrier 44, and the fixing device 36. .
The discharge section 16 has an inclined portion 52 that is rotatable with respect to the image forming apparatus main body 12. The inclined portion 52 has a lower outlet portion and is inclined so as to gradually increase toward the front (rightward in FIG. 1), with the outlet portion as the lower end and the raised tip as the upper end. The inclined portion 52 is supported by the image forming apparatus main body 12 so as to be rotatable about a lower end. As shown by a two-dot chain line in FIG. 1, when the inclined portion 52 is rotated upward and opened, an open portion 54 is formed, and a process cartridge 64 described later can be attached and detached via the open portion 54. .
The image forming means 14 is of, for example, an electrophotographic type, and includes an image carrier 44 made of a photoreceptor, a charging device 56 made of, for example, a charging roll for uniformly charging the image carrier 44, and a charging device 56 An optical writing device 58 for writing a latent image by light on the image carrier 44 charged by the optical writing device 58; a developing device 60 for visualizing the latent image of the image carrier 44 formed by the optical writing device 58 with a developer; The transfer device 42 formed of, for example, a transfer roll for transferring the developer image by the developing device 60 to the sheet, the cleaning device 62 formed of, for example, a blade for cleaning the developer remaining on the image carrier 44, and the image transferred by the transfer device 42 And a fixing device 36 for fixing the developer image on the sheet to the sheet. The optical writing device 58 is composed of, for example, a scanning type laser exposure device, is disposed near the front of the image forming apparatus main body 12 in parallel with the above-described paper feeding unit 18, and exposes the image carrier 44 across the inside of the developing device 60. . The exposure position of the image carrier 44 is a latent image writing position P.
In this embodiment, a scanning laser exposure device is used as the optical writing device 58. However, as another embodiment, an LED, a surface emitting laser, or the like can be used.
The process cartridge 64 integrates the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62. The process cartridge 64 is disposed immediately below the inclined portion 52 of the discharge unit 16 and is attached and detached via the opening 54 formed when the inclined portion 52 is opened as described above.
FIGS. 2 to 4 show the structure of the fixing device 36. FIG. The fixing device 36 is unitized and has a unit main body 66, and the unit main body 66 is configured by combining a first housing 68 and a second housing 70. That is, the first housing 68 and the second housing 70 are connected via the main body fulcrum 72, and the heating roll 74 is rotatably supported by the first housing 68. A pressure roll 76 is rotatably supported by the housing 70. The pressure roll 76 is pressed against the heating roll 74 by two elastic bodies 78 and 78 formed of a coil spring or the like, and a nip portion 80 is formed. One end of each of the elastic bodies 78, 78 is supported by the rotating cams 82, 82, and the other end is hooked on the first housing 68. The rotating cam 82 is rotatably supported by one end of a bracket 84, and expands and contracts the elastic body 78 by rotating. The other end of the bracket 84 is supported on a fulcrum 86. The bracket 84 is made of a conductive material, for example, stainless steel.
A heater 88 composed of a lamp is arranged in the heating roll 74 to heat the heating roll 74. The above-described transport path 32 is formed vertically with the nip 80 interposed therebetween, and the sheet is transported from bottom to top. An inlet chute (conveyance guide) 90 made of a conductive material, for example, a plate-like metal, is disposed upstream of the nip 80, and outlet chutes 92 a, 92 b are disposed downstream of the nip 80. . The outlet-side chutes 92a and 92b are provided on the first housing 68 side and the second housing 70 side, and the outlet-side chutes 92a on the second housing 70 side rotate upward. The paper is made to pass through.
A thermostat 94 is provided in the first housing 68 in the vicinity of the heating roll 74, and the thermostat 94 prevents a failure of the heating roll 74 due to an excessive temperature rise. A plurality of peeling claws 96 are provided in the first housing 68 near the downstream side of the nip 80 in the axial direction of the heating roll 74 (the width direction of the paper). The peeling claw 96 is urged toward the heating roll 74 with a weak force that does not damage the surface of the heating roll 74, and the tip of the peeling claw 96 is pressed against the surface of the heating roll 74 and wound around the heating roll 74. The paper to be removed is to be peeled off.
The heating roll 74 has a cylindrical core 98 and a release layer 100 coated on the surface of the core 98. The core 98 has an outer diameter of, for example, 25 mm and a thickness of, for example, 1 to 1.5 mm. The material forming the core 98 is, for example, iron or aluminum. The developer is, for example, negatively charged, and the core 98 is connected to a rectifier 102 composed of, for example, a Zener diode in a direction in which negative charges having the same polarity as the developer are held. Then, the heating roll 74 is grounded via the rectifier 102. The release layer 100 is formed of an insulating material, for example, insulating perfluoroalkoxy (PFA), and has a thickness of, for example, 30 to 100 μm.
Next, the pressure roll 76 and its peripheral structure will be described in detail.
The pressure roll 76 is, for example, a rotating shaft 104 made of stainless steel or iron and the like. It has an elastic layer 106 and a covering layer 108 covering the surface of the heat-resistant elastic layer 106. The coating layer 108 is made of a conductive material, for example, conductive PFA, and has a thickness of, for example, 30 to 100 μm, and is connected to the bias voltage source 112 via the conductive power supply terminal member 110. I have. For example, when the developer is negatively charged, the bias voltage source 112 applies a voltage of, for example, 200 V to the coating layer 108 via the power supply terminal member 110, and generates a positive charge having the opposite polarity to the developer. It is supplied to the coating layer 108.
The inlet chute 90 is connected to a bias voltage source 112 via a power supply terminal member 110. For example, when the developer is negatively charged, the bias voltage source 112 supplies a positive charge having a polarity opposite to that of the developer to the inlet chute 90 via the power supply terminal member 110. That is, each of the coating layer 108 and the inlet chute 90 is supplied with the bias voltage so that the developer can be attracted.
FIG. 5 is a schematic diagram showing power supply and grounding for the pressure roll 76, the inlet chute 90, and the heating roll 74. The rotating shaft 104 has first bearings 114, 114 formed of a conductive material, for example, a conductive resin at both ends. By fixing the first bearings 114, 114 to the brackets 84, 84, the pressure roll 76 is supported. Then, the pressure roll 76 is pressed against the heating roll 74 via the first bearing 114, the bracket 84, the rotating cam 82, and the elastic body 78. One side of the bracket 84 (the right side in FIG. 5) is grounded via the grounding terminal member 116. Therefore, the pressure roll 76 is grounded via the first bearing 114, the bracket 84, and the grounding terminal member 116.
A bias voltage source 112 is connected to the coating layer 108 via a power supply terminal member 110 on the end surface on the bracket 84 side (left side in FIG. 5) that is not grounded. On the other hand, a positive charge of the opposite polarity is supplied. That is, the pressure roll 76 is grounded at a position separated from the power supply terminal member 110. Then, the pressure roll 76 can attract the negatively charged developer. Note that the bracket 84 that is not grounded is preferably insulated from members disposed around.
A bias voltage source 112 is connected to the inlet chute 90 via a power supply terminal member 110, and a positive charge is supplied similarly to the pressure roll 76. Therefore, the inlet chute 90 can attract the negatively charged developer. The inlet chute 90 may be grounded via a load having a high resistance so that a positive charge can be maintained.
In the vicinity of both ends of the heating roll 74, second bearings 118 made of a conductive material and having, for example, stainless balls are mounted. The heating roll 74 is provided with a gear 120 at one end near the grounded bracket 84. The heating roll 74 is configured to rotate when the gear 120 receives a driving force from another gear (not shown). Further, one end of the rectifier 102 described above is connected to the second bearing 118 located near the grounded bracket 84. The rectifier 102 has one end connected to the second bearing 118 and the other end grounded so that the core 98 holds a negative charge having the same polarity as the negatively charged developer.
Next, the form of power supply or grounding for the pressure roll 76, the inlet chute 90 and the heating roll 74 will be described.
FIGS. 6 to 9 show forms of power supply to the pressure roll 76 and the inlet chute 90. A power supply terminal member 110 integrally formed of, for example, a metal plate is provided near one end (left side in FIG. 6) of the pressure roll 76. The power supply terminal member 110 constitutes a first power supply unit and a second power supply unit in the claims.
The power supply terminal member 110 has a fixing portion 122 fixed to the second housing 70 by using, for example, the elasticity of the terminal member. From the fixing portion 122, a first elastic portion 124 in the form of a leaf spring having appropriate elasticity extends toward the pressure roll 76. A first contact portion 126 is formed at the tip of the first elastic portion 124. The first contact portion 126 has a cross section formed, for example, in an arc shape, so that the first contact portion 126 is slidably in contact with the end of the coating layer 108 from below, and has a small contact area. Since the first elastic portion 124 is formed in such a curved shape, it does not damage the sheet passing through the nip portion 78 and the surface of the coating layer 108.
From the fixing portion 122, a second elastic portion 128 extends in the side direction of the inlet chute 90. A second contact portion 130 having a leaf spring shape is formed at the tip of the second elastic portion 128, and the second contact portion 130 is disposed on the side of the inlet chute 90 in the axial direction of the pressure roll 76. (In the direction from left to right in FIGS. 8 and 9). That is, since the inlet chute 90 is supported by a resin frame protrusion (not shown) in the fixing device 36 and urged from the side by the second elastic portion 128, the fixing member such as a screw is not used. Fixed.
Further, a power supply arm 132 extends from the fixing part 122, and a first main body connection part 134 having a surface facing the fixing part 122 is provided at the tip of the power supply arm 132. Is formed.
FIG. 10 shows a state in which the power supply terminal member 110 is mounted on the fixing device 36. When the power supply terminal member 110 is attached to the fixing device 36, the first main body connection portion 134 is exposed to the first housing 68 below the fixing device 36.
11 to 16 show details of the grounding terminal member 116 and its surroundings. The grounding terminal member 116 includes a first member 136, a second member 138, a third member 140, and the rectifier 102 that come into contact with other members with appropriate elasticity.
The first member 136 includes a fixing portion 142 fixed to the first housing 68 side, a heating roll contact portion 144 that contacts the second bearing 118 of the heating roll 74, and a forward direction of the rectifier 102. And a rectifier upstream contact portion 146 that contacts the upstream terminal.
The second member 138 includes a fixing portion 148 fixed to the first housing 68 side, a rectifier downstream contact portion 150 that contacts a terminal on the downstream side in the forward direction of the rectifier 102, and a fitting hole described later. 158, and a second main body connection portion 154.
The third member 140 has a fixing portion 156 fixed to the second housing 70 side, a fitting hole 158 for fitting the above-mentioned fitting leaf spring portion 152, and ground from the fixing portion 156. The ground arm 160 includes a grounding arm 160 extending downward from the bracket 84, and a bracket connecting part 162 provided at the tip of the grounding arm 160 and connected to the grounded bracket 84.
The rectifier 102 is provided between the first member 136 and the second member 138 as described above, and is connected so that the first member 136 side is upstream in the forward direction. Therefore, the core 98 of the heating roll 74 holds a negative charge of the same polarity as the negatively charged developer.
On the other hand, the rotation shaft 104 of the pressure roll 76 is grounded at one end via the first bearing 114, the bracket 84, the third member 140, and the second member 138, as described above.
FIG. 17 shows the second main body connection portion 154 and its periphery. When the grounding terminal member 116 is mounted on the fixing device 36, the second main body connection portion 154 is located below the fixing device 36 so that the second body connection portion 154 is in the opposite direction to the first main body connection portion 134. 70.
FIG. 18 shows a state where the fixing device 36 is mounted on the image forming apparatus main body 12. The image forming apparatus main body 12 includes main body side plates 164a and 164b at opposing positions, and is formed such that the fixing device 36 is pushed in substantially horizontally. The main body side plate 164a is provided with a ground terminal receiving portion 166 that is exposed in a grounded state, and the main body side plate 164b is configured to supply a necessary bias voltage to the pressure roll 76 and the inlet chute 90. An exposed power supply terminal receiving portion 168 is provided. When the fixing device 36 is pushed into the image forming apparatus main body 12, the second main body connection portion 154 abuts on the ground terminal receiving portion 166 on the second housing 70 side, and the first main body connection portion 154. The portion 134 contacts the power supply terminal receiving portion 168 on the first housing 68 side. Therefore, the fixing device 36 supplies the positive charge to the coating layer 108 and the inlet chute 90 without being provided with the bias voltage source 112 in the fixing device 36 by being pushed into the image forming apparatus main body 12. The core 98 can be grounded via the rectifier 102, and the rotating shaft 104 can be grounded.
Next, the operation of the above embodiment will be described.
When the image forming signal is sent, the image carrier 44 is uniformly charged by the charging device 56, and the charged image carrier 44 is irradiated with light emitted from the optical writing device 58 based on the image signal. , A latent image is formed at the latent image writing position P. Light from the optical writing device 58 passes through the process cartridge 64. The latent image of the image carrier 44 formed by the optical writing device 58 is visualized by the developer of the developing device 60. The developer is charged to have, for example, a negative charge.
On the other hand, one of the paper feed units 18 is selected by a size signal or the like, and the paper stored in one of the paper feed cassettes 22 is sent out by a pickup roll 24 and is fed by a retard roll 26 and a feed roll 28. The paper is separated and guided to the main transport path 32, temporarily stopped by the registration roll 38, and guided between the transfer device 42 and the image carrier 44 at a certain timing. When the sheet is guided between the transfer device 42 and the image carrier 44, the negatively charged developer on the image carrier 44 is transferred to the sheet by the transfer device 42.
FIG. 19 schematically shows a state in which the unfixed developer 170 is fixed on the sheet 172. The sheet 172 onto which the unfixed developer 170 has been transferred is transported upward along the main transport path 32 from between the transfer device 42 and the image carrier 44, and is heated by the inlet chute 90 to the heating roll 74 and the pressure roll 76. Guided between.
The inlet chute 90 is supplied with a stable positive charge from the bias voltage source 112 via the power supply terminal member 110. Then, the inlet chute 90 stabilizes the positive charge of the sheet 172 and electrostatically attracts the unfixed developer 170 to the surface of the sheet 172 from the back side of the sheet 172 (the left side of the sheet 172 in FIG. 19). The coating layer 108 of the pressure roll 76 is supplied with a stable positive charge from the bias voltage source 112 via the power supply terminal member 110. Then, the pressure roll 76 electrostatically attracts the unfixed developer 170 to the front surface of the paper 172 from the back side of the paper 172 (the left side of the paper 172 in FIG. 19). That is, since the inlet chute 90 and the coating layer 108 are positively charged, the transfer of the unfixed developer 170 to the heating roll 74 is prevented.
Further, since the heat roll 74 holds a negative charge in the core 98 by the rectifier 102, it prevents the unfixed developer 170 from adhering to the release layer 100 of the heat roll 74.
Then, when the sheet 172 is guided to the nip 80, the unfixed developer 170 is fixed to the sheet 172 by the heat pressure received from the heating roll 74 and the pressure roll 76. The paper 172 on which the developer has been fixed is discharged from the discharge port 34 to the discharge section 16.
As described above, the fixing device 36 stably supplies charges of the opposite polarity to the charged developer to the pressure roll 76 and the inlet chute 90, and heats the charges of the same polarity as the developer. It is held on a roll 74. Therefore, the developer can be attracted to the paper side, and the offset in which the developer adheres to the surface of the heating roll 74 can be prevented. Further, even if a cleaner is not provided on the heating roll 74, it is possible to prevent the unfixed developer 170 from adhering to the surface of the heating roll 74.
As described above, the same bias is supplied to the pressure roll 76 and the inlet chute 90. Therefore, even if the inlet chute 90 is arranged near the pressure roll 76, it is possible to prevent the charge from leaking from the surface of the pressure roll 76 to the inlet chute 90. Further, since the power supply terminal member 110 and the grounding terminal member 116 are arranged apart from each other, it is possible to prevent a charge from leaking between the power supply terminal member 110 and the grounding terminal member 116. it can.
In the power supply terminal member 110, since the first contact portion 126 is in smooth sliding contact with the coating layer 108, the bias voltage source 112 is independent of the hardness of the heat-resistant elastic layer 106 and the thickness of the coating layer 108. Can be reliably applied to the coating layer 108.
Further, since the first elastic portion 124 and the second elastic portion 128 are formed integrally with the power supply terminal member 110, the bias voltage source 112 applies a bias to both the pressure roll 76 and the inlet chute 90. The voltage can be supplied reliably, and the configuration can be made at low cost. Furthermore, since the second elastic portion 128 fixes the inlet chute 90 without using a fixing member such as a screw, the power supply terminal member 110 can be improved in recyclability and can be configured at low cost. it can.
Further, the fixing device 36 supplies the bias voltage to the pressure roll 76 and the inlet chute 90 by being pushed into the image forming apparatus main body 12 without providing the bias voltage source 112 in the fixing device 36. Can be. Similarly, when the fixing device 36 is pushed into the image forming apparatus main body 12, the heating roll 74 and the pressure roll 76 can be grounded, so that the image forming apparatus 10 receives the power supply terminal member 110 and the power supply terminal receiving member. The parts 168 are sealed with each other, so that safety can be improved while improving operability.
[0050]
As described above, according to the present invention, the bias voltage is applied to the transport guide for guiding the sheet between the heating roll and the pressure roll. The developer can be attracted to the paper even before the paper is conveyed during this time, and the image can be stably fixed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a fixing device according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating a side surface near an elastic body of the fixing device illustrated in FIG. 2;
FIG. 4 is a schematic diagram illustrating a cross section of the fixing device illustrated in FIG. 2;
FIG. 5 is a schematic diagram showing power supply and grounding for a pressure roll, an inlet chute, and a heating roll.
FIG. 6 is a perspective view showing an arrangement of a power supply terminal member with respect to a pressure roll and an inlet chute.
FIG. 7 is a perspective view illustrating a shape of a power supply terminal member.
FIG. 8 is an enlarged perspective view showing an arrangement of a power supply terminal member with respect to a pressure roll and an inlet chute.
FIG. 9 is a schematic diagram illustrating a state in which a second contact portion contacts an inlet chute.
FIG. 10 is a diagram illustrating a state in which the power supply terminal member is mounted on the fixing device.
FIG. 11 is a diagram showing an arrangement of grounding terminal members with respect to a heating roll and a pressure roll.
FIG. 12 is a perspective view showing a shape of a first member.
FIG. 13 is a perspective view showing a shape of a second member.
FIG. 14 is a perspective view showing a shape of a third member.
FIG. 15 is a perspective view showing a connection state of members constituting a ground terminal member.
FIG. 16 is an enlarged perspective view showing an arrangement of a grounding terminal member with respect to a heating roll and a pressure roll.
FIG. 17 is a diagram illustrating a configuration of a second main body connection portion and a periphery thereof.
FIG. 18 is a diagram illustrating a state in which the fixing device according to the embodiment of the present invention is mounted on the image forming apparatus main body.
FIG. 19 is a schematic diagram illustrating a state in which an unfixed developer is fixed on a sheet.
[Explanation of symbols]
10 Image forming apparatus
12 Image Forming Apparatus Main Body
14 Image Carrier Forming Means
36 Fixing device
66 Fixing device body
68 First housing
70 Second case
74 heating roll
76 Pressure roll
82 rotating cam
84 bracket
88 heater
90 Inlet chute
98 core
100 Release layer
102 rectifier
104 rotation axis
106 heat-resistant elastic layer
108 coating layer
110 Power supply terminal member
112 bias voltage source
114 1st bearing
116 Grounding terminal member
118 second bearing
122 fixing part
124 first elastic part
126 first contact portion
128 second elastic part
130 second contact part
132 Power supply arm
134 first body connection
154 second body connection
166 Ground terminal receiving part
168 Feeding terminal receiving part
170 Unfixed developer
172 paper

Claims (8)

A heating roll having a conductive core and an insulating release layer coated on the surface side of the core, and a pressure roll pressed against the heating roll and having a conductive coating layer on the surface, A conveyance guide that is provided near the pressure roll and guides a sheet between the heating roll and the pressure roll, a first power supply unit that applies a bias voltage to a coating layer of the pressure roll, A fixing device comprising: a second power supply unit that applies a bias voltage to the transport guide; and a ground unit that grounds the core via a rectifier. The first power supply unit and the second power supply unit supply power so that a bias voltage having a polarity opposite to the polarity of the developer is applied, and the rectifier supplies a charge having the same polarity as the polarity of the developer. The fixing device according to claim 1, wherein the fixing device is connected in a direction to be held by the core. The said 1st electric supply means is provided with the terminal member which has a contact part which contacts the coating layer of the said pressure roll, The said contact part is formed in the curved surface shape, The Claims 1 or 2 characterized by the above-mentioned. Fixing device. The first power supply unit and the second power supply unit are formed integrally with a first contact portion that contacts the coating layer of the pressure roll and a second contact portion that contacts the transport guide. The fixing device according to claim 1, further comprising a terminal member. The fixing device according to claim 1, wherein the first power supply unit, the second power supply unit, and the grounding unit are provided to be separated from each other. The fixing device according to claim 1, wherein the second power supply unit includes a terminal member that contacts the transport guide to supply power and fixes the transport guide. An image forming apparatus comprising the fixing device according to claim 1. The fixing device is unitized so as to be detachable from the apparatus main body, and the first and second power supply means and the grounding means are connected to the apparatus main body side in synchronization with the mounting of the fixing unit. The image forming apparatus according to claim 7, further comprising a receiving unit that receives the electrical connection.

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