JP5402742B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus that pass a sheet on which an unfixed image is formed through a fixing nip and thermally fix the unfixed image on the sheet.

  As a fixing device provided in a conventional image forming apparatus, Patent Document 1 discloses that a fixing belt provided with a resistance heating layer is disposed so as to surround an outer periphery of an elastic roller, and a pressure roller is provided from the outside of the fixing belt. A fixing device is disclosed that presses against an elastic roller via a fixing belt to secure a fixing nip between the surface of the fixing belt and a pressure roller and energizes the resistance heating layer of the fixing belt to heat the resistance heating layer. ing.

  Since this fixing device is configured to generate heat from the fixing belt itself, it has higher thermal efficiency than the configuration in which the fixing belt is heated by a dedicated heater separate from the fixing belt, and the temperature of the fixing nip becomes higher than the fixing temperature. There is an advantage that the time required to reach can be shortened.

JP 2009-109997 A

As in the fixing device disclosed in Japanese Patent Application Laid-Open No. 2004-260, a configuration in which power is supplied to the resistance heating layer provided on the fixing belt from the outside requires a configuration that can stably supply power over a long period of time.
In Patent Document 1, both ends of the fixing belt (belt portions positioned at both ends along the axial direction of the elastic roller) are provided so that electrodes electrically connected to the resistance heating layer are exposed to the outside. A configuration is adopted in which a pair of power supply rolls rotating in contact with the respective electrodes and following a fixing belt that runs around is arranged to supply power to the pair of power supply rolls.

Since the power supply roll rotates following the rotation of the fixing belt, friction at the contact portion between the power supply roll and the electrode is reduced, and wear of the power supply roll and the electrode is reduced.
However, Patent Document 1 discloses a power supply roll that supplies power to the resistance heating layer, but does not disclose anything about a configuration that supplies power from an external power source to the power supply roll.
As a configuration for supplying power to the rotating power supply roll, for example, a configuration in which the brush is rubbed against the outer peripheral surface of the power supply roll and power is supplied via the brush is conceivable. There is a problem that the wear of the brush tends to progress with the lapse of the driving time of the fixing device due to friction, and an early replacement is required, so that stable power supply cannot be performed.

Such a problem is not limited to the configuration in which the resistance heating layer is provided on the fixing belt, and may similarly occur in the configuration provided in a rotating body such as a roller.
SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device that can stably supply power from the outside to a resistance heating layer provided on a rotating body, and an image forming apparatus including the fixing device.

In order to achieve the above object, a fixing device according to the present invention secures a fixing nip between a first rotating body having a resistance heating layer and a second rotating body pressed against the first rotating body, and uses electric power from a power supply unit. A fixing device that energizes the resistance heating layer to heat the resistance heating layer and heat-fixes a sheet on which an unfixed image is formed through the fixing nip, wherein the first rotating body has an axial direction. A pair of electrodes electrically connected to the resistance heating layer on the peripheral surfaces at the first and second positions sandwiching the sheet passing area of the sheet, and the power feeding means includes the pair of electrodes. A rotating power supply member that is provided corresponding to each of the rotating power supply members and is driven to rotate by the first rotating body while the outer peripheral surface is in contact with the corresponding electrode; A rubbing power feeding member that rubs against a rotating power feeding member , Urging the rotary feeding member and the first supporting means for supporting movably in and away direction with respect to the electrodes of the first rotating body, in a direction toward said rotary feeding member to the electrode of the first rotary member Then, the first urging means for bringing the rotary power supply member into contact with the electrode, the rotary power supply member, and the rubbing power supply member are brought close to each other. A second support means that supports the slidable power feeding member and the rotary power supply member in the approaching direction, and slidably feeds the slidable power supply member and the rotary power supply. and a second biasing means to abut the predetermined portion of the member, the, Ri configuration der supplied to the electrode via the rotary feed member power from the external power source from the rubbing feeding member, wherein The first support means rotatably supports the rotary power feeding member. And a first support member that can move in the same direction together with the rotary power supply member as the rotary power supply member moves in the contact / separation direction, and the second support means includes the sliding power supply member. A second supporting member that supports the second supporting member, and the second supporting member is integral with the first supporting member and is movable in the same direction together with the first supporting member as the first supporting member moves; It is comprised by these.

Furthermore, the predetermined portion is an end face of a rotating shaft of the rotating power feeding member or a peripheral surface of the rotating shaft.
Further, the predetermined portion is a central portion of a side surface of the rotary power feeding member.
Further, the first rotating body is an endless belt, and is pressed against the second rotating body via the belt by a pressing member disposed inside the circulation path of the belt. An electrode is provided on the surface of the belt, and each of the rotating power supply members is disposed outside the belt circulation path and is driven to rotate in contact with the electrode provided on the surface of the belt. It is characterized by doing.

  An image forming apparatus according to the present invention includes the above-described fixing device.

  If the frictional power supply member is configured to contact the side surface portion of the rotary power supply member in this way, the frictional power supply member is rotationally supplied in the radial direction from the center of rotation of the rotary power supply member, rather than taking a configuration of contacting the outer peripheral surface. Since the length to the position in contact with the member is shortened, and the distance of one round when the frictional power supply member rubs against the rotary power supply member per rotation of the rotary power supply member is shortened, the friction per unit rotation speed This reduces the wear caused by, and enables stable power supply over a long period of time.

1 is a diagram illustrating an overall configuration of a printer. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 when the fixing unit provided in the printer is cut along the line AA. FIG. 3 is a cross-sectional view taken along an arrow when the fixing unit is cut along the line BB in FIG. 2. FIG. 3 is a cross-sectional view taken along an arrow when the fixing unit is cut along a line CC in FIG. 2. It is a schematic perspective view of a part of the fixing unit. 2 is a schematic cross-sectional view of a fixing belt provided in a fixing unit. FIG. It is a figure which shows the structure of the modification of the rotation electric power feeding member of a fixing part, and a frictional electric power feeding member. It is a figure which shows the structure of another modification of the rotation electric power feeding member of a fixing | fixed part, and a rubbing electric power feeding member.

Hereinafter, embodiments of a fixing device and an image forming apparatus according to the present invention will be described using a tandem color digital printer (hereinafter simply referred to as “printer”) as an example.
[1] Overall Configuration of Printer FIG. 1 is a diagram showing the overall configuration of the printer 1.
As shown in the figure, the printer 1 forms an image by a well-known electrophotographic system, and includes an image processing unit 10, an intermediate transfer unit 20, a feeding unit 30, and a fixing unit 40, and a network. When a print (print) job execution instruction is received from an external terminal device (not shown) connected to (for example, a LAN), yellow (Y), magenta (M), cyan (C) are received based on the instruction. And color image formation of black (K) color is executed.

  The image processing unit 10 includes image forming units 10Y to 10K corresponding to Y to K colors, respectively. The image forming unit 10Y includes a photosensitive drum 11Y and a charger 12Y, an exposure unit 13Y, a developing unit 14Y, a primary transfer roller 15Y, a cleaner for cleaning the photosensitive drum 11Y, and the like disposed around the photosensitive drum 11Y. A Y toner image is formed on the photosensitive drum 11Y through known charging, exposure, and development processes. This configuration is the same for the other image forming units 10M to 10K, and corresponding color toner images are formed on the photosensitive drums 11M to 11K.

The intermediate transfer unit 20 includes an intermediate transfer belt 21 that circulates in the direction of the arrow. The feeding unit 30 feeds the recording sheets S from the paper feeding cassette to the transport path 35 one by one.
The toner images formed on the photoconductive drums 11Y to 11K are primarily subjected to the circulating transfer on the intermediate transfer belt 21 under the action of electrostatic force by the transfer rollers 15Y to 15K at the transfer positions of the photoconductive drums 11Y to 11K. Transcribed. At this time, the image forming operation for each color is executed at different timings so as to be multiple-transferred to the same position on the intermediate transfer belt 21.

  The sheet S is conveyed from the feeding unit 30 at the timing of the image forming operation, and the sheet S is interposed between the intermediate transfer belt 21 and the secondary transfer roller 22 that is in pressure contact therewith. Each color toner image on the intermediate transfer belt 21 is secondarily transferred onto the sheet S at a time under the action of electrostatic force by the secondary transfer roller 22. The sheet S after the secondary transfer is sent to the fixing unit 40.

The fixing unit 40 includes a fixing belt 101 provided with a resistance heating layer that generates heat when energized, and fixes each color toner image on the sheet S after the secondary transfer to the sheet S by heating and pressing. The sheet S after fixing is discharged out of the apparatus via the discharge roller pair 38 and is stored on the storage tray 39.
[2] Configuration of Fixing Unit 40 FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 shows the fixing unit 40 along line BB in FIG. FIG. 4 is a cross-sectional view when the fixing unit 40 is cut along a line CC in FIG. 2. FIG. 5 is a schematic perspective view of the fixing unit 40, and FIG. 6 is a schematic cross-sectional view of the fixing belt 101. In FIG. 5, for the convenience of explanation, only main members are extracted and shown in a partially exploded manner.

2 to 6, the fixing unit 40 includes an endless fixing belt 101, a fixing roller 102, a pressure roller 103, a power feeding unit 104, a housing 105, and the like.
<Configuration of Fixing Belt 101>
The endless fixing belt 101 has a substantially cylindrical shape and is arranged so as to surround the outer periphery of the fixing roller 102. When a certain amount of force is applied in the radial direction of the fixing roller 102, the endless fixing belt 101 is elastically deformed and separated from the deformed state. If free, a self-holding shape that returns to its original cylindrical shape by its own restoring force is used.

As shown in FIG. 6, the fixing belt 101 is formed by laminating an insulating layer 111, a resistance heating layer 112, an elastic layer 113, and a release layer 114 in this order from the inner peripheral surface side.
The insulating layer 111 has a thickness of, for example, about 5 to 100 [μm] and is made of a heat resistant resin such as PI (polyimide), PPS (polyphenylene sulfide), PEEK (polyether ether ketone).

The resistance heating layer 112 has a thickness of, for example, about 5 to 100 [μm], and is made of a layer having a predetermined electrical resistivity by dispersing a conductive filler in the resin.
As the resin, heat-resistant resin such as PI, PPS, PEEK, etc. is used, and as the conductive filler, metals such as silver, copper, aluminum, magnesium, nickel, carbon type such as carbon nanotube, carbon nanofiber, carbon microcoil, etc. Either or both of these may be mixed and dispersed, or a mixture of other members may be used. As the shape, a fibrous shape is desirable in order to increase the probability of contact between fillers with the same content.

The electrical resistivity is an appropriate value in advance depending on the voltage applied to the resistance heating layer 112, the supply power, the layer thickness, the diameter of the fixing belt 101, the length of the fixing belt 101 in the X-axis direction (corresponding to the axial direction of the fixing roller 102), and the like. Is decided. For example, about 1.0 × 10 ^{−6 to} 9.9 × 10 ⁻³ [Ω · m], more preferably 1.0 × 10 ^{−5 to} 5.0 × 10 ⁻³ [Ω · m]. It is also good.
The elastic layer 113 has a thickness of, for example, about 100 to 300 [μm] and is made of an elastic material such as Si rubber or fluororubber.

  The release layer 114 has a thickness of, for example, about 5 to 100 [μm], and fluorine such as PFA (perfluoroalkoxy fluororesin), PTFE (polytetrafluoroethylene), ETFE (polyethylene / tetrafluoroethylene copolymer), or the like. It is made of a material having releasability such as a tube and a fluorine coating. It may be conductive. Examples of the fluorine-based tube include PFA350-J, 451HP-J, and 951HPPlus manufactured by Mitsui DuPont Fluorochemical Co., Ltd. The contact angle with water is preferably 90 ° or more, more preferably 110 ° or more. The surface roughness is preferably about Ra: 0.01 to 50 [μm].

The insulating layer 111 and the resistance heating layer 112 have a length in the X-axis direction of L2, and the elastic layer 113 and the release layer 114 have a length in the X-axis direction that is shorter than L2. This L1 corresponds to the maximum sheet passing width (sheet passing area) of the sheet S in the X-axis direction.
Of the resistance heating layer 112, a conductor layer 115 is provided on the surfaces of the first position and the second position across the sheet passing region of the sheet S in the X-axis direction instead of the elastic layer 113 and the release layer 114. Are stacked.

The conductor layer 115 is made of, for example, a metal material such as gold, copper, or nickel, and has a thickness in the range of, for example, 1 to 10 [μm], more preferably 2 to 5 [μm]. It is joined to the top and electrically connected to the resistance heating layer 112.
The conductor layer 115 functions as an electrode for supplying power from the power feeding unit 104 to the resistance heating layer 112. Hereinafter, it is referred to as an electrode 115.

The electrodes 115 are provided at both ends of the fixing belt 101 in the X-axis direction so that the surface is exposed over the entire circumference in the circumferential direction. The length of each electrode 115 in the X-axis direction is L3 (L1 and L1). The length obtained by dividing the difference of L2 into two equal parts). The length of L3 is determined so as to be longer than the width (the length in the roller axis direction) of the rotating body 161 of the rotating power feeding member 151 described later.
<Configuration of Fixing Roller 102>
As shown in FIG. 2, the fixing roller 102 is arranged inside the circulation path of the fixing belt 101, and an elastic layer 122 and a surface layer 123 are laminated around a long cored bar 121.

The metal core 121 as the shaft portion is made of aluminum, stainless steel, or the like. The elastic layer 122 is made of foamed rubber, resin, or the like, and the surface layer 123 is made of a PFA tube or the like.
The outer diameter of the fixing roller 102 is smaller than the inner diameter of the fixing belt 101, the fixing roller 102 and the fixing belt 101 are in contact with each other at the fixing nip N, and a gap (space) 110 is provided between them at a portion other than the fixing nip N. It is like that.

<Configuration of pressure roller 103>
The pressure roller 103 is formed by laminating an elastic layer 132 around a long metal core 131 and has an outer diameter of, for example, 20 to 100 [mm]. A fixing nip N is secured between the surface of the fixing belt 101 and the pressure roller 103 by pressing the fixing roller 102 via the fixing belt 101 from the outside.

The core bar 131 is made of aluminum, stainless steel, or the like, and the elastic layer 132 is made of a heat-resistant material such as silicone rubber or fluororubber, and has a thickness of, for example, 1 to 20 [mm]. A release layer made of a fluorine-based tube, a fluorine-based coating, or the like may be provided on the surface of the elastic layer 132. The release layer has a thickness of about 5 to 100 [μm] and may be conductive.
In the fixing roller 102, both end portions in the axial direction of the core metal 121 are rotatably supported by the frame 109 of the housing 105 via bearings 129, and both end portions in the axial direction of the core metal 131 are also supported by the frame 109 in the pressure roller 103. 139 is rotatably supported via 139.

The pressure roller 103 is rotationally driven in the direction of arrow a (FIG. 1) by transmission of driving force from a driving motor (not shown). Following the rotation of the pressure roller 103, the fixing belt 101 circulates in the direction of arrow b (FIG. 1) and the fixing roller 102 rotates in the same direction. The fixing roller 102 may be the driving side and the pressure roller 103 may be the driven side.
The core bars 121 and 131 may be solid or pipe-shaped. In the case of a pipe shape, for example, the thickness can be set to 0.1 to 10 [mm]. In addition, an irregular shape such as a three-pointed arrow shape may be used instead of a circular cross section.

<Configuration of Power Supply Unit 104>
The power supply unit 104 includes power supply units 104 a and 104 b that are spaced apart from each other in the X-axis direction of the fixing belt 101, and each has basically the same configuration. Hereinafter, the configuration of the power feeding unit 104a will be described, and the description of the power feeding unit 104b will be omitted.
The power supply unit 104a includes a rotary power supply member 151, a sliding power supply member 152, a support member 153, compression coil springs 154 and 155, a bearing 156, a power supply line 157a, and the like.

The rotating power supply member 151 includes a disk-shaped rotating body 161 and a rotating shaft 162 of the rotating body 161. The outer peripheral surface 163 of the rotating body 161 is in contact with one of the two electrodes 115 provided on the fixing belt 101.
The rotating body 161 and the rotating shaft 162 are made of a conductive member, for example, a metal such as copper, aluminum, brass, or phosphor bronze, and are integrally configured with the rotating shaft 162 and the rotating body 161 being electrically connected. However, different materials may be used as long as they are electrically connected. As another example, a structure in which an insulating material such as ceramic or resin is plated with copper, nickel, brass, or the like can be formed as the rotating power supply member 151.

The rubbing power supply member 152 has a cylindrical shape and is a carbon brush such as copper graphite or carbon graphite. Note that it is only necessary to be conductive, and a metal such as copper or nickel may be used. Here, a material whose hardness is lower than that of the rotating shaft 162 is used, but the material is not limited to this.
The support member 153 is a member that supports the rotary power supply member 151 and the frictional power supply member 152, is formed of an insulating and heat resistant resin, such as PI, PPS, PEEK, and the like. Three side plates 181, 182, 183 in a posture parallel to the Z-axis direction are provided on the surface at intervals along the X direction.

  U-shaped notches 171 (FIG. 4) are provided at the end portions 189 of the side plates 181 and 182 on the side facing the fixing belt 101. By fitting the two bearings 156 fitted on both ends of the rotating shaft 162 of the rotary power supply member 151 into the respective notches 171, the rotary power supply member 151 can be freely rotated on the support member 153 via the bearing 156. It has come to be supported. In order to restrict free movement of the rotary power supply member 151 in the axial direction with respect to the side plates 181 and 182, the rotary shaft 162 of the rotary power supply member 151 is tightly fitted to the inner ring of the bearing 156.

A cylindrical portion 185 extending toward the side plate 182 is provided on the surface of the side plate 183 facing the side plate 182. The cylindrical portion 185 has an opening at its distal end, and a compression coil spring 155 and a sliding power supply member 152 are inserted in this order from the opening.
The rubbing power supply member 152 is always supported in the advancing direction by the urging force of the compression coil spring 155 while being supported by the cylindrical portion 185 along the axial direction thereof so as to be movable forward and backward. It is energized.

The rubbing power supply member 152 is supported by the cylindrical portion 185 so that its axis is positioned substantially coaxially with the axis of the rotating shaft 162 of the rotary power supply member 151, and the sliding power supply member 152 is slid by the urging force of the compression coil spring 155. The end surface 159 (FIG. 5) of the frictional power supply member 152 is pressed against the end surface 169 (FIG. 5) of the rotating shaft 162 so that the end surface 159 and the end surface 169 are in surface contact with each other.
The rubbing power supply member 152 is configured to be restricted from rotating in the circumferential direction in the cylindrical portion 185. Here, although not shown in the drawing, a protruding portion extending in the axial direction is provided on the inner peripheral surface of the cylindrical portion 185, and a groove portion extending in the axial direction is provided on the outer peripheral surface of the frictional power feeding member 152. When the portion is fitted into the groove portion, a configuration is adopted in which rotation in the circumferential direction is prohibited while allowing movement of the frictional power feeding member 152 in the axial direction. Needless to say, the present invention is not limited to this configuration, and other configurations may be adopted.

  The side plate 183 is supported on the frame 109 of the housing 105 via the slide support portion 195. The slide support portion 195 is a mechanism that supports the side plate 183 with respect to the frame 109 so as to be movable only in the Z-axis direction (direction orthogonal to the X-axis and the Y-axis). For example, one of the side plate 183 and the frame 109 is provided with a ridge extending in the Z-axis direction, and the other is provided with a groove extending in the Z-axis direction so as to be slidable only in the Z-axis direction. A configuration in which the protruding portion is fitted into the groove portion is employed. However, the present invention is not limited to this, and other configurations may be adopted.

  The compression coil spring 154 is interposed between the base 180 and the frame 108 of the housing 105, and is biased in the direction in which the support member 153 approaches the fixing belt 101 along the Z-axis direction by the biasing force of the compression coil spring 154. Is done. Here, the direction of the urging force is a direction toward the cored bar 121 (axial core) of the fixing roller 102 (along the radial direction of the fixing roller 102) as shown in FIG. As a result, the state in which the outer peripheral surface of the rotating power supply member 151 is always pressed against the surface of the electrode 115 of the fixing belt 101 is maintained.

This pressing force is limited to such a magnitude that the fixing belt 101 does not dent. For example, a force in the opposite direction of the pressing force acts on the fixing belt 101 as a restoring force of the belt itself due to the pressing. Therefore, the compression coil spring 154 is attached so that a pressing force having the same magnitude as the restoring force is applied. Power is set.
Note that when the pressing force of the compression coil spring 154 is applied, such as the rigidity of the fixing belt 101 is low, the fixing belt 101 is greatly dented, and the contact state between the fixing belt 101 and the rotating power supply member 151 is not stable during rotation. A backing member (fixing member) that does not come into contact with the fixing roller 102 is disposed in the space 110 between the fixing belt 101 and the fixing roller 102 on the back surface side of the fixing belt 101, and the back side is pressed by the pressing force of the compression coil spring 154. A configuration may be adopted in which the fixing belt 101 is sandwiched between the contact member and the rotating power supply member 151.

The side plate 183 has a hole 191 formed in a portion corresponding to the bottom of the cylindrical portion 185, and a hole 192 is also formed in a portion of the frame 109 facing the hole 191.
The holes 191 and 192 are for inserting the power supply line 157a. One end of the power supply line 157a passes through the inside of the holes 192 and 191 and the tubular portion 185, and the end surface 158 (end surface 159) of the frictional power supply member 152 is inserted. Is fixedly connected to an end face (FIG. 5) opposite to the axial direction.

The other end of the power supply line 157a is connected to the power source 199. The power source 199 is, for example, an AC power source, and is electrically connected from the AC power source 199 to the rotary power supply member 151 via the power supply line 157a and the frictional power supply member 152. The same applies to the other power supply unit 104b.
As shown in FIG. 2, from the power source 199, the power feeding line 157a, the sliding power feeding member 152 of the power feeding unit 104a, the rotary power feeding member 151, the one electrode 115, the resistance heating layer 112, the other electrode 115, and the rotary power feeding of the power feeding unit 104b. A circuit connecting the power supply 199 and the resistance heating layer 112 is formed by electrically connecting the power supply 199 through the member 151, the frictional power supply member 152, and the power supply line 157b. Electric power is supplied to the resistance heating layer 112.

  In such a configuration, when the pressure roller 103 is rotationally driven and the fixing roller 102 is driven to rotate and the fixing belt 101 travels in the same direction together, the rotation power supply member 151 of the power supply units 104a and 104b is rotated. Each of them is driven to rotate in a direction opposite to the rotation direction of the fixing belt 101 by a frictional force generated between the outer peripheral surface 163 and the electrode 115 of the fixing belt 101.

While the fixing belt 101 rotates, power from the power source 199 is supplied to the resistance heating layer 112, and the resistance heating layer 112 is energized to generate heat, so that the fixing nip N reaches a predetermined fixing temperature. Thus, the amount of power from the power source 199 is adjusted.
The rotating power supply member 151 receives power from the frictional power supply member 152 that is in contact with the end surface 169 of the rotating shaft 162 while being rotated by the rotating fixing belt 101, and gives the received power to the electrode 115. .

  The rubbing power supply member 152 is in contact with the end surface 169 of the rotation shaft 162 of the rotary power supply member 151, and this contact position is substantially the same as the rotation center of the rotary power supply member 151. The distance to the contact position (radial distance) is almost zero. The longer the distance in the radial direction, the longer the distance of one rotation when the frictional power supply member 152 rubs against the rotary power supply member 151 per one rotation of the rotary power supply member 151. Wear increases.

The distance in the radial direction is the longest in the configuration in which the frictional power supply member 152 is brought into contact with the outer peripheral surface 163 of the rotary power supply member 151. On the other hand, if the configuration of the present embodiment is adopted as described above, the radial distance can be made almost zero.
Therefore, by adopting the configuration of the present embodiment, the frictional power supply member 152 and the rotary power supply member 151 are significantly worn compared to the configuration in which the frictional power supply member 152 is brought into contact with the outer peripheral surface 163 of the rotary power supply member 151. The power can be stably supplied over a long period of time.

  Further, since the rotary power supply member 151 is constantly pressed against the fixing belt 101 by the compression coil spring 154, the orbit of the belt portion of the fixing belt 101 facing the rotary power supply member 151 is caused by vibration during the rotation of the fixing belt 101. Even if there is a slight change in the Z-axis direction (the direction in which the rotary power supply member 151 is closer to the fixing belt 101), the rotary power supply member 151 changes in a state of being pressed against the fixing belt 101 so as to follow the change.

As a result, during rotation of the fixing belt 101, the rotating power feeding member 151 is separated from or abuts the fixing belt 101 due to a change in the orbit of the rotation, so that the power supply to the resistance heating layer 112 is performed for one rotation of the fixing belt 101. It is possible to prevent power supply to the resistance heating layer 112 more stably by preventing intermittent interruption.
Further, since the frictional power supply member 152 is always pressed against the rotating shaft 162 of the rotating power supply member 151 by the compression coil spring 155, even if a slight change occurs in the X-axis direction during the rotation of the rotating power supply member 151, The sliding power supply member 152 changes in a state where it is pressed against the rotary power supply member 151 so as to follow the change.

Thereby, even if the rotational power supply member 151 is displaced in the X-axis direction, the sliding power supply member 152 and the rotational power supply member 151 are prevented from being separated from each other, so that the power supply to the resistance heating layer 112 can be performed more stably. it can.
Further, the side plates 181 and 182 that are support members of the rotating power supply member 151 and the side plate 183 that is a support member of the frictional power supply member 152 are integrally configured. As a result, when the rotary power supply member 151 is displaced in the Z-axis direction due to vibration of the fixing belt 101, the frictional power supply member 152 is also displaced by the same amount in the same direction along with the change. The positional relationship between the end surface 159 and the end surface 169 (FIG. 5) of the rotation shaft 162 of the rotary power supply member 151 does not change, and the frictional power supply member 152 and the rotary power supply member 151 do not shift in the Z-axis direction.

Therefore, when the rotary power supply member 151 is displaced in the Z-axis direction, the frictional power supply member 152 and the rotary power supply member 151 are prevented from being separated due to the change, and the amount of change becomes a certain size. Even if it becomes, the stable electric power feeding to the resistance heating layer 112 is realizable.
[3] Modifications The present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and the following modifications can be considered.

(1) In the above embodiment, the location where the frictional power supply member 152 is in contact with the rotary power supply member 151 is defined as a predetermined location on the side surface except the outer peripheral surface 163 of the rotary power supply member 151. Although the example made into the end surface 169 was demonstrated, it is not restricted to this.
If the predetermined portion is a portion other than the outer peripheral surface 163 of the rotary power supply member 151, wear due to friction between the rotary power supply member 151 and the frictional power supply member 152 can be reduced as compared with the configuration of the outer peripheral surface 163. it can.

For example, as shown in FIG. 7, the rotating shaft 162 of the rotating power supply member 151 may be slightly extended, and the frictional power supplying member 152 may be brought into contact with the peripheral surface of the extended shaft portion.
Further, as shown in FIG. 8A, when the rotary power supply member 151 has a configuration in which the rotary shaft 165 does not protrude from the side surface 168 of the rotary body 161 on the side of the frictional power supply member 152, the frictional power supply member. The center portion of the side surface 168 of the rotating body 161 (the portion including the axis of the rotating body 161) can be set as a predetermined portion 152.

Further, as shown in FIG. 8B, the position is not limited to the central portion of the side surface 168 of the rotating body 161, and a portion of the side surface 168 between the position corresponding to the axial center and the outer edge in the radial direction is slid as a predetermined location. It is also possible to adopt a configuration in which the frictional power supply member 152 is in contact.
Although the rubbing power supply member 152 is a cylindrical member, it is limited to this shape as long as it is a power feeding brush that can supply power while rubbing against the rotating power supply member 151 that rotates following the fixing belt 101. It goes without saying that there is nothing.

  (2) In the above embodiment, the rotary power feeding member 151 is pressed against the electrode 115 of the fixing belt 101 by the biasing force of the compression coil spring 154. However, depending on the configuration of the apparatus, a configuration in which the biasing force by the spring is not used may be employed. . For example, it can be considered that the rotating power supply member 151 is in contact with the fixing roller 102 only by its own weight. The present invention can be applied to a case where the change of the rotation path of the fixing belt 101 during the rotation can gradually follow the change due to the weight of the rotating power feeding member 151. If this structure is taken, the compression coil spring 154 becomes unnecessary.

(3) In the above embodiment, a configuration example has been described in which the frictional power supply member 152 is pressed against the rotary power supply member 151 by the urging force of the compression coil spring 155 while freely supporting the movement of the rotary power supply member 151 in the axial direction. However, any configuration may be used as long as the frictional power supply member 152 and the rotary power supply member 151 are urged in a direction relatively approaching along the axial direction.
For example, the rotational power supply member 151 is supported freely while restricting the movement in the axial direction with respect to the frictional power supply member 152, and the rotational power supply member 151 is pressed against the frictional power supply member 152 by the biasing force of a spring, A configuration may be adopted in which both are movably supported in the axial direction and are urged by separate springs in directions approaching each other.

(4) In the above-described embodiment, the configuration example in which the rotating power feeding member 151 is pressed against the fixing belt 101 using the biasing force of the compression coil spring 154 has been described. However, the means for obtaining the biasing force is not limited to the compression coil spring. A general urging means that can obtain an urging force by an elastic force such as a spring or rubber having another shape can be used. The same applies to the compression coil spring 155.
(5) In the embodiment described above, the side plates 181 and 182 that are the support members of the rotary power supply member 151 and the side plate 183 that is the support member of the frictional power supply member 152 are integrated to form the rotary power supply member 151. When the fixing belt 101 is displaced along the Z-axis direction due to vibrations or the like, the side plates 181 and 182 that support the rotary power supply member 151 along with the displacement are moved together with the rotary power supply member 151 in the same Z-axis direction (rotary power supply member). The side plate 183 that supports the frictional power supply member 152 also moves together in the same direction while moving in the direction in which the 151 moves toward and away from the electrode 115 of the fixing belt 101, so that the rotational power supply member 151 and the frictional power supply member 152 are moved together. However, the positional relationship is not limited to this. It is also possible to take a mechanism in which both are separated and made independent.

  For example, the amount of displacement of the rotary power supply member 151 in the Z-axis direction due to vibration of the fixing belt 101 is small, and even if the rotary power supply member 151 and the frictional power supply member 152 are relatively displaced in the Z-axis direction, the two are separated. If the configuration does not lead to the above, the support member of the rotary power supply member 151 and the support member of the frictional power supply member 152 are made independent, the rotary power supply member 151 is in the Z-axis direction, and the frictional power supply member 152 is It is also possible to adopt a two-axis configuration that supports each movable in the X-axis direction.

  Even if the amount of displacement in the Z-axis direction of the rotational power supply member 151 is large to some extent, when the rotational power supply member 151 is displaced to the maximum displacement amount, the surface 159 of the frictional power supply member 152 and the rotational axis of the frictional power supply member 152 If the size of the surface 159 of the frictional power supply member 152 is large enough to maintain a state in which the surface 169 of the 162 is partly in contact with the surface 169, the surface of the frictional power supply member 152 is rubbed against the support member of the rotary power supply member 151. It is also possible to adopt a configuration in which the support member of the power feeding member 152 is made independent.

  (6) In the above-described embodiment, the fixing belt 101 has the annular electrode 115 on the surface (outer peripheral surface), and the rotary power feeding member 151 is disposed outside the circulation path of the fixing belt 101. It is not limited to. For example, it is possible to adopt a configuration in which the annular electrode 115 is provided on the back surface (inner peripheral surface) of the fixing belt 101 and the rotating power supply member 151 is disposed inside the circulation path of the fixing belt 101. In the case of this configuration, the rotating power supply member is disposed in the space 110 existing inside the circulation path of the fixing belt 101, and therefore, the present invention can be applied to an apparatus having a space 110 having a space that can secure this arrangement space. .

  (7) In the above embodiment, the first rotating body having the resistance heating layer is used as the fixing belt 101, and the fixing roller 102 is an example of a pressing member disposed in the circulation path of the fixing belt 101. Although the configuration example in which the pressure roller 103 is pressed via the fixing belt 101 has been described, the configuration is not limited thereto. For example, when a higher rigidity belt is used as the fixing belt 101, the fixing belt 101 is pressed by the pressure roller 103 while supporting the both ends of the fixing belt 101 in the width direction without providing the fixing roller 102. Thus, a configuration in which the fixing nip N is secured between the pressure roller 103 and the fixing belt 101 is assumed.

  Further, in the configuration example in which the space 110 exists between the fixing belt 101 and the fixing roller 102 except for the fixing nip N, the present invention is not limited to this. For example, the space 110 does not exist, that is, the back surface of the fixing belt 101 is fixed. A configuration in which the roller 102 is in close contact with the surface can also be adopted. Further, for example, the fixing belt 101 may not be provided, and the fixing roller 102 may be the first rotating body, and electrodes may be disposed at both ends thereof.

In addition, although the configuration example using the pressure roller 103 as the second rotating body that presses the first rotating body to secure the fixing nip has been described, the configuration is not limited thereto, and for example, a belt may be used.
(8) In the above embodiment, an example in which the fixing device and the image forming apparatus according to the present invention are applied to a tandem type color digital printer has been described, but the present invention is not limited to this. Regardless of color or monochrome image formation, the first rotating body having the resistance heating layer is pressed by the second rotating body to secure a fixing nip between the first and second rotating bodies and to supply power. For example, a copier, FAX, MFP (Multiple Function) can be used as long as the fixing device is configured to supply power to the resistance heating layer by the unit and heat the resistance heating layer by the current flowing in the resistance heating layer, and the image forming apparatus including the fixing device. Peripheral) etc.

In addition, it goes without saying that the shape, material, size, length, thickness, and the like of each member included in the fixing belt 101, the fixing roller 102, the pressure roller 103, the power feeding unit 104, and the like are not limited to those described above. Instead, the shape, material, dimensions, etc. suitable for the configuration are determined according to the device configuration. Note that the power supplied to the resistance heating layer is not limited to alternating current, and there may be a direct current configuration.
The contents of the above embodiment and the above modification may be combined.

  The present invention can be applied to a fixing device and an image forming apparatus in which an unfixed image on a sheet is thermally fixed by a rotating body having a resistance heating layer that generates heat when energized.

DESCRIPTION OF SYMBOLS 1 Printer 40 Fixing part 101 Fixing belt 102 Fixing roller 103 Pressure roller 104 Feeding part 112 Resistance heating layer 115 Conductor layer (electrode)
162, 165 Rotating shaft 151 Rotating feeding member 152 Sliding feeding member 153 Support member 154, 155 Compression coil spring 159 End surface of sliding feeding member 168 Side surface of rotating feeding member 169 End surface of rotating shaft of rotating feeding member 185 Cylindrical portion 195 Slide Support section N Fixing nip

Claims (5)

A fixing nip is secured between the first rotating body having the resistance heating layer and the second rotating body pressed against the first rotating body, and the resistance heating layer is heated by energizing the resistance heating layer with electric power from the power supply means. A fixing device for thermally fixing a sheet on which an unfixed image is formed through the fixing nip,
The first rotating body includes:
A pair of electrodes electrically connected to the resistance heating layer on the circumferential surfaces at the first and second positions sandwiching the sheet passing area of the sheet in the axial direction;
The power supply means is
A rotating power feeding member that is provided corresponding to each of the pair of electrodes and whose outer peripheral surface is in contact with the corresponding electrode and rotates following the first rotating body;
A rubbing power feeding member that is in contact with a predetermined location on the side surface of the rotating power feeding member and rubs against the rotating power feeding member that is driven to rotate;
First support means for supporting the rotary power supply member so as to be movable in the contact / separation direction with respect to the electrode of the first rotating body;
A first urging unit that urges the rotating power feeding member in a direction approaching the electrode of the first rotating body, and abuts the rotating power feeding member on the electrode;
Second support means for supporting the rotary power supply member and the rubbing power supply member so as to be relatively movable in a direction in which the rubbing power supply member and a predetermined portion of the rotary power supply member approach each other;
A second urging unit that urges at least one of the rubbing power supply member and the rotary power feeding member in the approaching direction, and abuts the rubbing power feeding member and a predetermined portion of the rotary power feeding member;
Have
Configuration der supplied to the electrode power from the external power source from the rubbing feeding member through said rotary feeding member is,
The first support means includes
A first support member that rotatably supports the rotary power supply member and is movable in the same direction together with the rotary power supply member as the rotary power supply member moves in the contact / separation direction;
The second support means includes
A second support member for supporting the sliding power supply member;
The second support member is
A fixing device that is integral with the first support member and is movable in the same direction together with the first support member as the first support member moves . The predetermined location is
The fixing device according to claim 1, wherein the fixing device is an end surface of a rotating shaft of the rotating power feeding member or a peripheral surface of the rotating shaft. The predetermined location is
The fixing device according to claim 1 or 2, characterized in that a central portion of the side surface of said rotary feeding member. The first rotating body includes:
It is an endless belt, and is pressed against the second rotating body via the belt by a pressing member disposed on the inner side of the circulation path of the belt,
The pair of electrodes includes:
Provided on the surface of the belt,
Each of the rotating power supply members is
4. The belt according to any one of claims 1 to 3 , wherein the belt is driven outside the belt while being in contact with an electrode provided on a surface of the belt. Fixing device. An image forming apparatus comprising: a fixing device according to any one of claims 1 to 4.

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