JP4534682B2 - Fixing device and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device used in an image forming apparatus using, for example, an electrophotographic method, and more particularly to a fixing device including a rotatable belt member.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, for example, a photosensitive member (photosensitive drum) formed in a drum shape is uniformly charged, and the photosensitive drum is controlled based on image information. An electrostatic latent image is formed on the photosensitive drum by exposure with the exposed light. The electrostatic latent image is converted into a visible image (toner image) with toner, and the toner image is transferred onto the recording paper from the photosensitive drum, and then the toner image is fixed on the recording paper with a fixing device.

  A fixing device used in such an image forming apparatus includes a heat source inside a cylindrical metal core, and is formed by laminating a heat-resistant elastic layer on the metal core and a release layer on the outer peripheral surface thereof. The fixing roll is press-fitted to the fixing roll, and is formed by laminating a heat-resistant elastic body layer on the metal core and a release layer made of a heat-resistant resin film or a heat-resistant rubber film on the outer peripheral surface thereof. It consists of a pressure roll. Then, the recording paper carrying the unfixed toner image is passed between the fixing roll and the pressure roll, and the unfixed toner image is heated and pressed to thereby form the toner image on the recording paper. It has become established. Such a fixing device is called a roll nip system and is generally widely used.

In recent years, with the progress of high productivity and colorization in image forming apparatuses, and the spread of double-sided printing mechanisms, it has been required that fixing apparatuses also support high speed. At that time, in the roll nip type fixing device, it is necessary to set the nip width widely in proportion to the fixing speed so that a sufficient amount of heat can be supplied to the toner and the recording paper. As a method of widening the nip width, a method of increasing the load between the fixing roll and the pressure roll, a method of increasing the thickness of the elastic layer, and a method of increasing the roll diameter are conceivable.
However, in the method of increasing the load or the method of increasing the thickness of the elastic layer, the shape of the nip width due to the deflection of the roll becomes non-uniform along the roll axis. There is a problem in image quality such as being easily generated. In addition, the method of increasing the roll diameter causes problems that the apparatus is increased in size and the time (warm-up time) until the roll is raised from room temperature to a fixable temperature is increased.

  Therefore, in order to solve these problems and realize a fixing device corresponding to the speeding up of the image forming apparatus, the applicant of the present invention has a rotatable fixing roll whose surface is elastically deformed and remains in contact with the fixing roll. An endless belt capable of traveling and a pressure pad arranged in a non-rotating state inside the endless belt, and the endless belt is pressed against the fixing roll so that a contact surface with the fixing roll is formed by the pressure pad. And a belt nip so that the sheet can be passed between the endless belt and the fixing roll, and a fixing device configured to locally elastically deform the exit side of the sheet on the surface of the fixing roll. The technique regarding this is proposed (for example, refer patent document 1).

  In the fixing device described in Patent Document 1 (referred to as “belt nip method”), the endless belt is brought into pressure contact with the fixing roll using a pressure pad instead of the pressure roll in the conventional roll nip type fixing device. By adopting such a configuration, the width of the belt nip formed by the fixing roll and the endless belt can be easily made larger than the width of the conventional roll nip between the fixing roll and the pressure roll. Since a uniform and high nip pressure can be applied to the portion, it is possible to cope with a high speed, and it is easy to reduce the size of the apparatus.

  Furthermore, since the heat capacity of the endless belt pressed against the fixing roll is small, and the pressure pad is arranged in a non-rotating state, a configuration in which heat transmitted from the fixing roll is not easily dissipated to the outside is realized. Therefore, even when the rotation of the fixing roll is started, the amount of heat taken from the fixing roll to the endless belt side is small, the thermal efficiency at the time of melting the toner can be increased, and the amount of temperature decrease at the belt nip is also small. There is also an advantage that the fixing property of the toner can be improved.

Japanese Patent No. 3298354 (pages 4-7)

  By the way, in the above-described belt nip type fixing device, when the endless belt is brought into pressure contact with the fixing roll by the pressure member, it is necessary to ensure slipperiness (reduction in sliding resistance) between the pressure member and the endless belt. . Therefore, a low friction member made of a material having a small friction coefficient is fixedly disposed between the pressure member and the endless belt, and sliding is performed while applying a lubricant to the friction surface between the low friction member and the endless belt. I am letting.

However, since a pressing force is applied to the sliding portion between the low friction member and the endless belt, the sliding portion pushes the lubricant toward the outer side of both end portions of the endless belt. The force to try to act. For this reason, the lubricant held on the inner peripheral surface of the endless belt tends to gradually shift toward both end portions of the endless belt, so that there is a problem that some lubricant leaks to the outside from both end edges of the endless belt. . As a result, the amount of lubricant applied at the center of the endless belt gradually decreases and the sliding resistance between the low friction member and the endless belt increases, so that the endless belt loses its smoothness of rotation. There is a disadvantage that the possibility of generating paper wrinkles and image misalignment increases.
In addition, the leaked lubricant infiltrates into the elastic body such as silicone rubber or fluororubber constituting the pressure member, so that the elasticity of the pressure member is gradually lost, resulting in a decrease in the nip pressure at the nip portion. There is also a new problem that image defects such as uneven gloss are likely to occur.

  Accordingly, the present invention has been made to solve the technical problems as described above, and an object of the present invention is to cause the lubricant held by the belt member to be shifted toward both ends of the belt member in the fixing device. It is in suppressing.

  For this purpose, the fixing device of the present invention is a fixing device for fixing a toner image carried on a recording material, and includes a rotating member, a belt member rotatable while being in contact with the rotating member, A belt guide member that supports the belt member from the inside, and the belt guide member is arranged on the contact surface with the belt member from the upstream side to the downstream side in the rotation direction of the belt member, in the center in the width direction of the belt member. It has a plurality of grooves formed to be inclined in the direction.

Here, a pressure member is further provided which is disposed inside the belt member and presses the belt member against the rotating member to form a nip portion through which the recording material passes between the rotating member and the belt member. be able to. Further, the belt guide member may be arranged on the downstream side in the rotation direction of the belt member of the pressure member. Further, the belt guide member may be characterized in that the side surface of the groove is formed as an inclined surface. In addition, the belt guide member may be characterized in that the upper edge of the groove is formed with a curved surface. Furthermore, the belt guide member can be configured such that the cross-sectional shape of the groove is formed in a triangular shape.
Moreover, it can be set as the structure further provided with the heating member which heats a rotation member, or the heating member which heats a belt member.

The fixing device of the present invention is a fixing device that fixes a toner image carried on a recording material, and holds a lubricant on a rotating member and an inner peripheral surface, and rotates while contacting the rotating member. A movable belt member, and a lubricant collecting member that collects the lubricant held on the inner peripheral surface of the belt member in the width direction central portion direction in the entire width region of the belt member. It is a feature.
Here, the lubricant gathering member can be characterized in that the contact surface with the belt member is arranged so as to be directed downward from above in the vertical direction. In addition, the lubricant collecting member may be configured such that a lubricant application member that applies lubricant to the inner peripheral surface of the belt member is disposed on the downstream side in the rotation direction of the belt member.

  Further, the present invention is regarded as an image forming apparatus. The image forming apparatus of the present invention includes a toner image forming unit that forms a toner image, and a transfer unit that transfers the toner image formed by the toner image forming unit onto a recording material. A fixing means for fixing the toner image transferred onto the recording material to the recording material, the fixing means including a rotating member, a belt member rotatable while being in contact with the rotating member, and an inner side of the belt member A pressure member that presses the belt member against the rotating member to form a nip portion through which the recording material passes between the rotating member and the belt member, and supports the belt member from the inside, and the belt member; And a belt guide member having a plurality of grooves formed by inclining in the width direction central portion direction of the belt member from the upstream side to the downstream side in the rotation direction of the belt member. It is said.

  As an effect of the present invention, the smoothness of the rotation of the belt member can be ensured by suppressing the deviation of the lubricant held by the belt member in the fixing device toward both ends of the belt member. It became possible to form quality images. Further, by suppressing the leakage of the lubricant to the outside, it is possible to suppress the decrease in the nip pressure at the nip portion, so that it is possible to maintain the formation of a fixed image with excellent gloss.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[Embodiment 1]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus to which the exemplary embodiment is applied. The image forming apparatus shown in FIG. 1 is an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of image forming units 1Y, 1M, 1C, and 1K on which toner images of respective color components are formed by electrophotography. The primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15, and the superimposed toner image transferred onto the intermediate transfer belt 15. Are provided with a secondary transfer unit 20 that collectively transfers (secondary transfer) to a paper P that is a recording material (recording paper), and a fixing device 60 that fixes the secondary transferred image onto the paper P. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  In the present embodiment, each of the image forming units 1Y, 1M, 1C, and 1K has a charger 12 that charges the photosensitive drum 11 around the photosensitive drum 11 that rotates in the direction of arrow A, and the photosensitive drum 11. A laser exposure device 13 for writing an electrostatic latent image thereon (exposure beam is indicated by a symbol Bm in the figure), each color component toner is accommodated, and the electrostatic latent image on the photosensitive drum 11 is visualized with toner. A developing unit 14, a primary transfer roll 16 that transfers each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15 in the primary transfer unit 10, and a drum cleaner that removes residual toner on the photosensitive drum 11. 17 and the like are sequentially arranged. These image forming units 1Y, 1M, 1C, and 1K are arranged in a substantially straight line from the upstream side of the intermediate transfer belt 15 in the order of yellow (Y), magenta (M), cyan (C), and black (K). Has been.

The intermediate transfer belt 15 as an intermediate transfer member is constituted by a film-like endless belt in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide. The volume resistivity is 10 ⁶ to 10 ¹⁴ Ωcm, and the thickness is, for example, about 0.1 mm. The intermediate transfer belt 15 is circulated and driven (rotated) at a predetermined speed in the direction B shown in FIG. 1 by various rolls. As these various rolls, a drive roll 31 that is driven by a motor (not shown) excellent in constant speed and rotates the intermediate transfer belt 15, and an intermediate that extends substantially linearly along the arrangement direction of the photosensitive drums 11. A support roll 32 that supports the transfer belt 15, a tension roll 33 that functions as a correction roll that applies a constant tension to the intermediate transfer belt 15 and prevents meandering of the intermediate transfer belt 15, and a backup provided in the secondary transfer unit 20. A cleaning backup roll 34 provided in a cleaning unit for scraping off residual toner on the roll 25 and the intermediate transfer belt 15 is provided.

The primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ⁷ to 10 ⁹ Ωcm. The primary transfer roll 16 is placed in pressure contact with the photosensitive drum 11 with the intermediate transfer belt 15 in between, and the primary transfer roll 16 has a voltage (with negative polarity; the same applies hereinafter) having a polarity opposite to that of the toner. (Primary transfer bias) is applied. As a result, the toner images on the respective photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so as to form superimposed toner images on the intermediate transfer belt 15.

The secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image carrying surface side of the intermediate transfer belt 15 and a backup roll 25. The backup roll 25 is composed of a tube of EPDM and NBR blend rubber with carbon dispersed on the surface, and EPDM rubber on the inside. And it is formed so that the surface resistivity may be 10 ⁷ to 10 ¹⁰ Ω / □, and the hardness is set to 70 ° (Asker C), for example. The backup roll 25 is disposed on the back side of the intermediate transfer belt 15 to form a counter electrode of the secondary transfer roll 22, and a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact with the backup roll 25. ing.

On the other hand, the secondary transfer roll 22 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ⁷ to 10 ⁹ Ωcm. The secondary transfer roll 22 is disposed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded, and a secondary transfer bias is formed between the secondary transfer roll 22 and the backup roll 25. The toner image is secondarily transferred onto the paper P conveyed to the transfer unit 20.

  Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer and cleans the surface of the intermediate transfer belt 15. A cleaner 35 is provided so as to be able to contact and separate. On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 that generates a reference signal serving as a reference for taking image forming timings in the image forming units 1Y, 1M, 1C, and 1K. It is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit. 1Y, 1M, 1C, and 1K are configured to start image formation.

  Further, in the image forming apparatus according to the present embodiment, as a paper transport system, a paper tray 50 that stores paper P, a pickup roll 51 that picks up and transports the paper P accumulated in the paper tray 50 at a predetermined timing, and a pickup A transport roll 52 that transports the paper P fed by the roll 51, a transport chute 53 that feeds the paper P transported by the transport roll 52 to the secondary transfer unit 20, and transported after being secondarily transferred by the secondary transfer roll 22. A conveyance belt 55 that conveys the paper P to be fixed to the fixing device 60 and a fixing inlet guide 56 that guides the paper P to the fixing device 60 are provided.

  Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described. In the image forming apparatus as shown in FIG. 1, image data output from an image reading device (IIT) not shown or a personal computer (PC) not shown is subjected to predetermined image processing by an image processing device (IPS) not shown. After being applied, the image forming operation is executed by the image forming units 1Y, 1M, 1C, and 1K. In IPS, the input reflectance data is subjected to predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing. Is done. The image data that has undergone image processing is converted into color material gradation data of four colors, Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K, for example, with an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. Yes. In each of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photosensitive drums 11 and the intermediate transfer belt 15 come into contact with each other. Transcribed. More specifically, in the primary transfer portion 10, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (minus polarity) is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, and the toner image. Are sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is conveyed to the secondary transfer unit 20, in the paper conveyance system, the pickup roll 51 rotates in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 20, so P is supplied. The paper P supplied by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport chute 53. Before reaching the secondary transfer unit 20, the paper P is temporarily stopped, and a registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is carried. And the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the sheet P conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Is done. The unfixed toner image carried on the intermediate transfer belt 15 is collectively electrostatically transferred onto the paper P in the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the backup roll 25. .

Thereafter, the sheet P on which the toner image has been electrostatically transferred is transported as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and transported downstream of the secondary transfer roll 22 in the sheet transport direction. It is conveyed to the belt 55. The conveying belt 55 conveys the paper P to the fixing device 60 in accordance with the optimum conveying speed in the fixing device 60. The unfixed toner image on the paper P conveyed to the fixing device 60 is fixed on the paper P by being subjected to a fixing process by heat and pressure by the fixing device 60. Then, the paper P on which the fixed image is formed is conveyed to a paper discharge placement unit provided in a discharge unit of the image forming apparatus.
On the other hand, after the transfer onto the paper P is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and the cleaning backup roll 34 and the intermediate transfer belt cleaner 35 are transferred. Is removed from the intermediate transfer belt 15.

  Next, the fixing device 60 used in the image forming apparatus of the present embodiment will be described. FIG. 2 is a side sectional view showing a configuration of the fixing device 60 of the present embodiment. The fixing device 60 includes a fixing roll 61 as an example of a rotating member, an endless belt 62 as an example of a belt member, and a pressure pad 64 as an example of a pressure member pressed from the fixing roll 61 via the endless belt 62. The main part is composed.

The fixing roll 61 is a cylindrical roll configured by laminating a heat-resistant elastic body layer 612 and a release layer 613 around a metal core (cylindrical cored bar) 611, and is rotatably supported. Rotates at a predetermined surface speed.
Inside the fixing roll 61, for example, a halogen heater 66 having a rating of 600 W is disposed as a heat source. On the other hand, a temperature sensor 69 is disposed in contact with the surface of the fixing roll 61. The control unit 40 of the image forming apparatus controls the lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69 so that the surface temperature of the fixing roll 61 maintains a predetermined set temperature (for example, 175 ° C.). It is adjusted to.

  The endless belt 62 is a seamless endless belt, the pressure pad 64 disposed inside the endless belt 62, the upstream belt guide member 63 a and the downstream belt guide member 63 b, and both ends of the endless belt 62. It is rotatably supported by an edge guide member 80 (see FIG. 3 in the subsequent stage) as an example of a belt regulating member disposed in the section. Then, it is disposed so as to be pressed against the fixing roll 61 at the nip portion N, and rotates following the fixing roll 61.

Here, FIG. 3 is a diagram illustrating a configuration in which the endless belt 62 is supported, and shows one end region of the fixing device 60 as viewed from the downstream side in the conveyance direction of the paper P.
As shown in FIG. 3, both end portions in the width direction of the endless belt 62 are supported by edge guide members 80 fixed to both end portions of the holder 65 disposed inside the endless belt 62. The edge guide member 80 is provided on the outer side of the belt traveling guide portion 801 having a cylindrical shape in which a notch is formed in a portion corresponding to the nip portion N and the vicinity thereof, that is, a C-shaped cross section, A flange portion 802 formed with an outer diameter larger than the outer diameter of the endless belt 62 and a holding portion for positioning and fixing the edge guide member 80 to the fixing device 60 main body provided on the outer surface of the edge guide member 80. 803.
The endless belt 62 rotates at the both ends in the width direction of the endless belt 62 following the fixing roll 61 while the inner peripheral surfaces of both ends are supported by the edge guide member 80. Further, the endless belt 62 is restricted from moving in the width direction of the endless belt 62 (belt walk) by the flange portion 802, so that the endless belt 62 is prevented from being displaced.

On the other hand, in the region excluding both end portions in the width direction of the endless belt 62, the endless belt 62 is supported by the pressure pad 64, the upstream belt guide member 63a, and the downstream belt guide member 63b (see also FIG. 2). And in the area | region except the both ends of the endless belt 62, the low friction sheet | seat 68 arrange | positioned so that the internal peripheral surface of the endless belt 62 may cover the pressure pad 64 and the upstream belt guide member 63a, and a downstream belt guide It rotates while rubbing against the member 63b.
The upstream belt guide member 63 a and the downstream belt guide member 63 b are attached to a holder 65 disposed inside the endless belt 62 along the longitudinal direction. The downstream belt guide member 63b that directly rubs against the inner peripheral surface of the endless belt 62 is made of a material having a low friction coefficient so that the endless belt 62 can smoothly rotate, and the endless belt 62 It is made of a material with low thermal conductivity so that it is difficult to take heat away from it. Specifically, a heat resistant resin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polyphenylene sulfide (PPS) is used.
On the other hand, the upstream belt guide member 63a that slides on the inner peripheral surface of the endless belt 62 via the low friction sheet 68 is also formed of a material having low thermal conductivity.

  Next, the pressure pad 64 is supported by a metal holder 65 inside the endless belt 62. Then, it is arranged in a state of being pressed against the fixing roll 61 via the endless belt 62, and forms a nip portion N with the fixing roll 61. In the pressure pad 64, a pre-nip member 64 a for securing a wide nip portion N is disposed on the inlet side (upstream side) of the nip portion N. Further, on the outlet side (downstream side) of the nip portion N, the surface of the fixing roll 61 is locally pressed to smooth the surface of the toner image and impart image gloss, and the surface of the fixing roll 61 is distorted (dented). ) To form a down curl on the sheet P, and a separation nip member 64b for separating the sheet P from the surface of the fixing roll 61 is disposed.

The pressure pad 64 is provided with a low friction sheet 68 as an example of a low friction member on the surface in contact with the endless belt 62 in order to reduce the sliding resistance between the inner peripheral surface of the endless belt 62 and the pressure pad 64. It has been.
The low friction sheet 68 has an upstream end of the nip portion N fixed to the bottom surface of the holder 65 by a downstream belt guide member 63b. The upstream belt guide member 63a is covered and disposed in a state of being sandwiched between the pressure pad 64 and the inner peripheral surface of the endless belt 62 in the entire nip portion N. The downstream side of the nip portion N of the low friction sheet 68 is not fixed and set to a free end (free) state so that the low friction sheet 68 is not distorted. The low friction sheet 68 has a sliding resistance between the inner peripheral surface of the endless belt 62 and the pressure pad 64 under a state in which a pressing force is applied between the pressure pad 64 and the fixing roll 61 at the nip portion N. (Friction resistance) is reduced.

  In such a configuration, the fixing roll 61 is connected to a drive motor (not shown) and rotates in the direction of arrow C, and the endless belt 62 rotates in the same direction as the fixing roll 61 following this rotation. The sheet P on which the toner image is electrostatically transferred in the secondary transfer unit 20 of the image forming apparatus shown in FIG. 1 is guided by the fixing inlet guide 56 and conveyed to the nip N. When the paper P passes through the nip portion N, the toner image on the paper P is fixed by the pressure acting on the nip portion N and the heat supplied from the fixing roll 61. In the fixing device 60 of the present embodiment, since the nip portion N can be configured widely by the concave pre-nip member 64a that substantially follows the outer peripheral surface of the fixing roll 61, stable fixing performance can be ensured.

  In the vicinity of the downstream side of the nip portion N, the paper P peeled off from the fixing roll 61 by the peeling nip member 64b is completely separated from the fixing roll 61 and guided to the paper discharge path toward the discharge portion of the image forming apparatus. A peeling assisting member 70 is provided for this purpose. The peeling auxiliary member 70 is held by a baffle holder 72 in a state in which the peeling baffle 71 is close to the fixing roll 61 in a direction (counter direction) opposite to the rotation direction of the fixing roll 61.

Next, each member constituting the fixing device 60 will be described in detail. First, in the fixing roll 61, the core 611 is formed of a cylindrical body made of a metal having high thermal conductivity such as iron, aluminum, or SUS, for example, an outer diameter of 30 mm, a wall thickness of 1.8 mm, and a length of 360 mm. .
The heat-resistant elastic body layer 612 is composed of an elastic body having high heat resistance, and it is particularly preferable to use an elastic body such as rubber or elastomer having a rubber hardness of about 15 to 45 ° (JIS-A). Specifically, silicone rubber, fluorine rubber, or the like can be used. In the fixing device 60 of the present embodiment, the core 611 is coated with a silicone HTV rubber having a rubber hardness of 35 ° (JIS-A) with a thickness of 600 μm.

  For the release layer 613, for example, a heat-resistant resin such as a silicone resin or a fluororesin is used, but a fluororesin is suitable from the viewpoint of the releasability to the toner and the wear resistance. As the fluororesin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like can be used. The thickness of the release layer 613 is preferably 5 to 30 μm. In fixing device 60 of the present embodiment, PFA having a thickness of 30 μm is coated.

  The endless belt 62 is a seamless endless belt whose original shape is formed in a cylindrical shape so that a defect caused by the seam does not occur in the output image. The base layer and the surface of the base layer on the fixing roll 61 side ( Outer peripheral surface) or a release layer coated on both sides. For the base layer, a polymer such as a thermosetting polyimide resin, a thermoplastic polyimide resin, a polyamideimide resin, or a polybenzimidazole resin is preferably used from the viewpoint of heat resistance, mechanical properties, and the like. The thickness is set to about 30 to 200 μm, preferably 50 to 125 μm, more preferably about 75 to 100 μm.

As the release layer to be coated on the surface of the base layer, a fluororesin is used. Here, as the fluororesin, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether, particularly from the viewpoint of heat resistance, mechanical properties and the like. A copolymer (MFA), a tetrafluoroethylene-perfluoroethyl vinyl ether copolymer (EFA), and a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) are preferably used. The thickness is set to about 5 to 100 μm, preferably about 10 to 30 μm.
In the fixing device 60 of the present embodiment, the endless belt 62 has a configuration in which a release layer made of PFA having a thickness of 30 μm is laminated on a base layer made of thermosetting polyimide having a peripheral length of 94 mm, a thickness of 75 μm, and a width of 320 mm. Is used.

As described above, the pressure pad 64 disposed in the endless belt 62 includes the pre-nip member 64a and the peeling nip member 64b. The prenip member 64a is supported by the holder 65 so as to press the fixing roll 61 with a load of, for example, 35 kgf by a spring or an elastic body. An elastic body such as silicone rubber or fluororubber, a leaf spring, or the like can be used for the prenip member 64 a, and the surface on the fixing roll 61 side is formed with a concave curved surface that substantially follows the outer peripheral surface of the fixing roll 61. In the fixing device 60 of the present embodiment, silicone rubber having a width of 10 mm, a thickness of 5 mm, and a length of 320 mm is used.
The peeling nip member 64 b is directly supported by the holder 65, and the holder 65 is set at a predetermined position with respect to the fixing roll 61, thereby coming into contact with the fixing roll 61 with a predetermined pressing force. Further, the peeling nip member 64b is formed of a heat-resistant resin such as PPS, polyimide, polyester, or polyamide, or a metal such as iron, aluminum, or SUS. As the shape of the peeling nip member 64b, the outer surface shape in the nip portion N is formed as a convex curved surface having a constant radius of curvature.
In the fixing device 60 of the present embodiment, the endless belt 62 is wrapped around the fixing roll 61 by the pressure pad 64 (the pre-nip member 64a and the peeling nip member 64b) at a winding angle of about 40 ° and has a width of about 10 mm. A nip portion N is formed.

  Further, a lubricant application member 67 is disposed on the bottom surface of the downstream side belt guide member 63b along the longitudinal direction of the fixing device 60. The lubricant application member 67 is disposed so as to contact the inner peripheral surface of the endless belt 62 and supplies an appropriate amount of lubricant. As a result, the lubricant is supplied to the sliding portion between the endless belt 62 and the low friction sheet 68, and the sliding resistance between the endless belt 62 and the pressure pad 64 via the low friction sheet 68 is further reduced. 62 is smoothly rotated. Further, it has an effect of suppressing wear on the inner peripheral surface of the endless belt 62 and the surface of the low friction sheet 68.

  As the lubricant, a lubricant that has durability against long-term use under a fixing temperature environment and can maintain wettability with the inner peripheral surface of the endless belt 62 is suitable. For example, liquid oil such as silicone oil or fluorine oil, synthetic lubricating oil grease in which a solid substance and a liquid are mixed, or a combination thereof can be used. Silicone oils include dimethyl silicone oil, dimethyl silicone oil with organometallic salt addition, dimethyl silicone oil with hindered amine addition, dimethyl silicone oil with organometallic salt and hindered amine addition, methylphenyl silicone oil, amino-modified silicone oil, amino-modified silicone-added amino-modified silicone. Oil, hindered amine-added amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, sulfonic acid-modified silicone oil, and the like can also be used. Moreover, as fluoro oil, perfluoropolyether oil and modified perfluoropolyether oil can be used. In the fixing device 60 of the present embodiment, amino-modified silicone oil is used.

Next, the surface shape of the downstream belt guide member 63b that supports the endless belt 62 while directly rubbing with the inner peripheral surface of the endless belt 62 in the region excluding both ends in the width direction of the endless belt 62 will be described. Here, the width direction of the endless belt 62 refers to a direction orthogonal to the rotational direction of the endless belt 62 (the same applies hereinafter).
FIG. 4 is a perspective view of the downstream side belt guide member 63b as viewed obliquely from below, and FIG. 5 is a bottom view of the downstream side belt guide member 63b. 4 and 5, the endless belt 62 rotates in the direction indicated by the arrow in the drawing. As shown in FIGS. 4 and 5, the rotation direction of the endless belt 62 extends over substantially the entire longitudinal direction on the surface of the downstream belt guide member 63b that rubs against the inner peripheral surface of the endless belt 62. Are provided with a plurality of grooves 631 formed at predetermined intervals. The groove 631 is formed so as to be inclined inward with respect to the direction from the upstream side to the downstream side in the rotational direction of the endless belt 62. That is, the grooves 631 arranged symmetrically on the left and right sides with respect to the central portion in the longitudinal direction are formed so as to be inclined toward the central portion in the longitudinal direction toward the rotational direction of the endless belt 62.

As described above, the surface of the downstream side belt guide member 63b that supports the endless belt 62 while directly rubbing with the inner peripheral surface of the endless belt 62 is inclined toward the central portion in the longitudinal direction over substantially the entire longitudinal direction. By forming the plurality of grooves 631, the lubricant applied to the inner peripheral surface of the endless belt 62 can be gathered along the grooves 631 toward the central portion in the longitudinal direction.
FIG. 6 is a diagram for explaining a state in which the groove 631 gathers the lubricant applied to the inner peripheral surface of the endless belt 62 in the longitudinal center direction. As shown in FIG. 6, when the inner peripheral surface of the endless belt 62 slides on the surface of the downstream belt guide member 63b as the endless belt 62 rotates, the lubrication retained on the inner peripheral surface of the endless belt 62 is achieved. The agent is led to a groove 631 formed on the surface of the downstream side belt guide member 63b, so that the agent is gathered in the central direction in the longitudinal direction.

  Specifically, on the surface of the downstream side belt guide member 63b, a part of the lubricant held on the inner peripheral surface of the endless belt 62 is stripped off by stripping the side surface of each groove 631 in the longitudinal center portion side. The applied lubricant is guided downstream along the groove 631 by the adhesive force with the inner peripheral surface of the endless belt 62 as it is conveyed downstream as the endless belt 62 rotates. In particular, as shown in FIG. 2, the surface (contact surface) of the downstream side belt guide member 63b is formed so as to extend from the upper side to the lower side in the direction of gravity (vertical direction), and therefore, the lubrication that has been peeled off. In addition to the adhesive force with the inner peripheral surface of the endless belt 62, the agent also acts by gravity, so that it is easily guided downward along the groove 631. The lubricant is conveyed to the downstream side of the downstream belt guide member 63b while being gathered along the groove 631 in the longitudinal center direction by the rotation of the endless belt 62 and the action of gravity. The lubricant is applied to the lubricant application member 67 disposed on the bottom surface of the downstream belt guide member 63b.

By the way, in the fixing device 60 of the present embodiment, as described above, the pressure pad 64 is disposed so as to press the fixing roll 61 at the nip portion N, and therefore, the low friction disposed on the pressure pad 64. A pressing force (nip pressure) is applied between the sheet 68 and the endless belt 62 at the nip portion N. Therefore, in the nip portion N, a force pushed out from the nip portion N acts on the lubricant held on the inner peripheral surface of the endless belt 62, and the lubricant tries to move toward both ends of the nip portion N. To do. Therefore, the application amount of the lubricant on the inner peripheral surface of the endless belt 62 that has passed through the nip portion N is larger in the both end regions, and there is an imbalance in the application amount in the width direction such that the center portion is smaller. Such an imbalance in which the amount of lubricant applied becomes smaller at the center increases the sliding resistance between the low friction sheet 68 and the endless belt 62, thus preventing smooth rotation of the endless belt 62, This causes paper wrinkles and image misalignment at the nip portion N.
In addition, the lubricant that is offset in the direction of both ends of the nip portion N finally leaks to the outside, and the leaked lubricant infiltrates into an elastic body such as silicone rubber or fluorine rubber that constitutes the pressure pad 64, so that the pressure gradually increases. As a result of the loss of elasticity of the pad 64 and a decrease in nip pressure at the nip portion N, an image defect such as uneven gloss may occur in the fixed image.

  Therefore, in the fixing device 60 of the present embodiment, the downstream belt guide member 63b of the present embodiment is disposed on the downstream side of the nip portion N. By disposing such a downstream belt guide member 63b, as described above, the lubricant that has been offset toward the both end regions in the width direction in the nip portion N can be gathered in the direction of the central portion by the groove 631, so that The problem that the coating amount of the agent becomes smaller at the central portion can be solved, and the coating amount of the lubricant on the inner peripheral surface of the endless belt 62 can be made uniform. From this point of view, the downstream side belt guide member 63b functions as a lubricant collecting member that collects the lubricant in the central portion direction on the inner peripheral surface of the endless belt 62.

  Further, since the lubricant collected in the central direction by the downstream belt guide member 63b is collected by the lubricant application member 67, the amount of lubricant retained in the lubricant application member 67 is larger in the longitudinal center. Become. Therefore, the amount of lubricant applied to the inner peripheral surface of the endless belt 62 by the lubricant application member 67 is relatively greater at the center than at both ends, and therefore after passing through the lubricant application member 67. In the path to the nip portion N, on the inner peripheral surface of the endless belt 62, the lubricant application amount can be relatively large at the central portion and relatively small at both end portions. That is, since the amount of lubricant applied in the nip portion N in the direction toward both ends of the nip portion N can be anticipated in advance and the amount of lubricant applied can be increased in the center portion than in the both end portions, However, it becomes easy to make the amount of the lubricant uniform, and it is also possible to suppress the leakage of the lubricant from both ends.

In this way, by disposing the downstream belt guide member 63b of the present embodiment on the downstream side of the nip portion N, the lubricant that has moved in the direction of both ends in the nip portion N is gathered again to the center portion, It is possible to form a cycle in which the amount of lubricant applied to the inner peripheral surface of the endless belt 62 is relatively increased toward the center than at both ends, and then sent to the nip portion N again. Thereby, a substantially uniform state in the width direction of the endless belt 62 can be maintained with respect to the lubricant application amount on the inner peripheral surface of the endless belt 62. Therefore, since the sliding resistance between the low friction sheet 68 and the endless belt 62 can be maintained at a low level, smooth rotation of the endless belt 62 can be maintained. It is possible to suppress the occurrence of image shift.
Furthermore, by realizing the uniformity of the lubricant application amount, it is possible to suppress the leakage of the lubricant from the inner peripheral surface of the endless belt 62 to an extremely low level. Thereby, since the leaked lubricant does not infiltrate into the pressure pad 64, the nip pressure can be maintained at a predetermined value, and a high-quality image without uneven gloss can be maintained.

  By the way, the convex part 632 between the groove | channel 631 and the groove | channel 631 is formed in the plane where the upper surface is smooth, and the upper surface of all the convex parts 632 is formed on the same plane. Therefore, the endless belt 62 is uniformly supported by the upper surface of the convex portion 632 and rotates while sliding on the upper surface of the convex portion 632. In this case, as described above, the downstream belt guide member 63b is formed of a material having a small friction coefficient such as PFA, and the lubricant is applied to the inner peripheral surface of the endless belt 62. Sliding between the belt 62 and the upper surface of the convex portion 632 is performed smoothly. In particular, since the contact area between the endless belt 62 and the surface of the downstream belt guide member 63b is configured to be small only in the groove 631, there is an effect of further reducing the sliding resistance.

7 is an enlarged view of the surface of the downstream side belt guide member 63b. As shown in FIG. 7, the side surface of the convex portion 632 (side surface of the groove 631) is, for example, an inclined surface having a 45 ° inclination ( (C-plane) is preferable. This is because when the convex portion 632 is formed by a side surface standing at a right angle, for example, the lubricant is likely to stay in both corner portions of the groove 631, so that the lubricant is guided downward along the groove 631. This is because the conveyance efficiency of the sheet is reduced.
Furthermore, the depth of the groove 631 is preferably about 0.5 mm. When the groove 631 becomes deeper, the lubricant in the groove 631 and the inner peripheral surface of the endless belt 62 cannot be contacted, and the adhesion force between the lubricant and the inner peripheral surface of the endless belt 62 does not work. This is because the movement of 62 in the rotational direction is difficult to occur, and the effect of gathering the lubricant in the longitudinal central portion cannot be sufficiently obtained. In addition, if the groove 631 is too shallow, the lubricant that has shifted to both end regions particularly in the nip portion N cannot be sufficiently scraped off by the groove 631. When the depth of the groove 631 is about 0.5 mm, it is preferable that the cut length of the above-described C surface (side surface) having an inclination of 45 ° is set to about C0.5 mm.

In addition, the upper surface edge of the convex portion 632 (the upper edge of the groove 631; see FIG. 7) is preferably formed in a curved surface (R shape). Since the upper surface edge of the convex portion 632 slides on the inner peripheral surface of the endless belt 62, the sliding resistance with the inner peripheral surface of the endless belt 62 is reduced, and the smoothness of the rotation of the endless belt 62 is maintained. Furthermore, in order to suppress wear on the inner peripheral surface of the endless belt 62, it is preferable to form it with a smooth curved surface.
In addition to the rectangular wave shape, the cross-sectional shape of the groove 631 can be formed in a triangular shape. By making it triangular, the bottom surface of the groove 631 is inclined (slope shape), so that it is easy to collect the lubricant in one place in the groove 631. For this reason, even when the endless belt 62 is stopped, it is easy to guide the lubricant below the groove 631 only by the action of gravity.

  The entire volume of the groove 631 formed in the downstream belt guide member 63b is larger than the volume of the lubricant that is substantially applied from the lubricant applying member 67 to the inner peripheral surface of the endless belt 62. Preferably it is. With this configuration, even when all of the lubricant applied to the inner peripheral surface of the endless belt 62 enters the groove 631, excess lubricant does not come out, so that leakage of the lubricant to the outside does not occur. It does not occur.

As described above, in the fixing device 60 according to the present embodiment, on the surface of the downstream belt guide member 63b that supports the endless belt 62 while directly rubbing with the inner peripheral surface of the endless belt 62, in the center in the longitudinal direction. A plurality of grooves 631 that are inclined toward the surface are provided. With the downstream belt guide member 63b having such a configuration, the lubricant that has moved in the direction of both end portions on the inner peripheral surface of the endless belt 62 can be collected again in the central portion, so that the lubricant application on the inner peripheral surface of the endless belt 62 can be performed. With respect to the amount, a substantially uniform state can be maintained in the width direction of the endless belt 62. Therefore, since the sliding resistance between the low friction sheet 68 and the endless belt 62 can be maintained at a low level, smooth rotation of the endless belt 62 can be maintained. It is possible to suppress the occurrence of image shift.
Furthermore, by realizing the uniformity of the lubricant application amount, it is possible to suppress the leakage of the lubricant from the inner peripheral surface of the endless belt 62 to an extremely low level. Therefore, since the leaked lubricant does not infiltrate into the pressure pad 64, the nip pressure can be maintained at a predetermined value, and a high-quality image without uneven gloss can be maintained.

[Embodiment 2]
In the first embodiment, the image forming apparatus is described in which the fixing roll 61 having a heat source is used as the heating unit and the fixing device 60 using the endless belt 62 with the pressure pad 64 pressed as the pressing unit is mounted. In the second embodiment, a fixing device mounted on the image forming apparatus shown in FIG. 1 is a fixing device using a fixing belt with a heat generation source pressed as a heating unit and a pressure roll as a pressing unit. explain. In addition, about the structure similar to Embodiment 1, the same code | symbol is used and the detailed description is abbreviate | omitted here.

  FIG. 8 is a side sectional view showing a configuration of the fixing device 90 in the present embodiment. As shown in FIG. 8, in the fixing device 90 of the present embodiment, a fixing belt 92 as an example of a belt member is disposed on the toner image carrying surface side of the paper P. A ceramic heater 82 which is a resistance heating element as an example of a heat source is disposed inside the fixing belt 92, and heat is supplied from the ceramic heater 82 to the nip portion N.

The ceramic heater 82 has a substantially flat surface on the pressure roll 91 side. Then, it is arranged in a state of being pressed against the pressure roll 91 via the fixing belt 92 and forms a nip portion N. Therefore, the ceramic heater 82 also functions as a pressure member. The sheet P that has passed through the nip portion N is peeled off from the fixing belt 92 by the change in the curvature of the fixing belt 92 in the exit region (peeling nip portion) of the nip portion N.
Further, in order to reduce the sliding resistance between the inner peripheral surface of the fixing belt 92 and the ceramic heater 82 between the inner peripheral surface of the fixing belt 92 and the ceramic heater 82, a low friction sheet 68 as an example of a rubbing member. Is arranged. The low friction sheet 68 may be configured separately from the ceramic heater 82 or may be configured integrally with the ceramic heater 82.

  On the other hand, a pressure roll 91 as an example of a rotating member is disposed so as to face the fixing belt 92 and is rotated in the direction of arrow D by a drive motor (not shown), and the fixing belt 92 is driven to rotate by this rotation. Has been. The pressure roll 91 includes a core (cylindrical cored bar) 911, a heat-resistant elastic body layer 912 coated on the outer peripheral surface of the core 911, and a release layer 913 made of a heat-resistant resin coating or a heat-resistant rubber coating. Has been configured.

The fixing belt 92 is an endless belt whose original shape is formed in a cylindrical shape, and includes a base layer 921 made of a thermosetting polyimide resin, a thermoplastic polyimide resin, a polyamideimide resin, a polybenzimidazole resin, and the like, and the base layer. And a release layer 922 made of a fluororesin or the like, which is coated on the surface (outer peripheral surface) or both surfaces on the pressure roll 91 side.
Here, the fixing belt 92 includes a ceramic heater 82 disposed inside the fixing belt 92, an upstream belt guide member 93 a and a downstream belt guide member 93 b, and belt regulation disposed at both ends of the fixing belt 92. It is rotatably supported by an edge guide member (not shown) as an example of the member. In the fixing device 90 of the present embodiment, since the low friction sheet 68 is configured to cover only the ceramic heater 82, the upstream belt guide member 93 a and the downstream belt guide member 93 b are both included in the fixing belt 92. The fixing belt 92 is supported while directly rubbing against the peripheral surface.

The paper P on which the toner image has been electrostatically transferred in the secondary transfer unit 20 of the image forming apparatus shown in FIG. 1 is guided to the nip N of the fixing device 90 by the fixing inlet guide 56. When the paper P passes through the nip portion N, the toner image on the paper P is fixed by the pressure acting on the nip portion N and the heat supplied from the ceramic heater 82 on the fixing belt 92 side. Also in the fixing device 90 of the present embodiment, since the nip portion N can be configured widely between the pressure roll 91 and the ceramic heater 82, stable fixing performance can be ensured.
As an auxiliary means for completely separating the fixed sheet P from the fixing belt 92, a peeling assisting member 70 can be disposed on the downstream side of the nip portion N of the fixing belt 92. The peeling auxiliary member 70 is held by a baffle holder 72 in a state where the peeling baffle 71 is close to the fixing belt 92 in a direction (counter direction) opposite to the rotation direction of the fixing belt 92.

Here, in the fixing device 90 of the present embodiment, both the upstream belt guide member 93a and the downstream belt guide member 93b that support the fixing belt 92 while sliding directly on the inner peripheral surface of the fixing belt 92 are implemented. Similar to the downstream side belt guide member 63b in the first embodiment, a plurality of grooves 631 that are inclined toward the central portion in the longitudinal direction along the rotational direction of the fixing belt 92 are provided on the surface.
By both the upstream belt guide member 93a and the downstream belt guide member 93b having such a configuration, the lubricant that has moved toward both ends on the inner peripheral surface of the fixing belt 92 can be gathered again to the central portion, so that the fixing belt With respect to the amount of lubricant applied to the inner peripheral surface of 92, a substantially uniform state in the width direction of the fixing belt 92 can be maintained. Therefore, since the sliding resistance between the low friction sheet 68 and the fixing belt 92 can be maintained at a low level, smooth rotation of the fixing belt 92 can be maintained. It is possible to suppress the occurrence of image shift. In particular, since both the upstream belt guide member 93a and the downstream belt guide member 93b gather the lubricant that has moved in the direction of both ends toward the center, the lubricant applied to the inner peripheral surface of the fixing belt 92 is greatly increased. A uniform effect can be obtained.
Furthermore, by realizing the uniformity in the amount of applied lubricant, leakage of the lubricant from the inner peripheral surface of the fixing belt 92 can be suppressed to an extremely low level. Therefore, since the lubricant can be used efficiently, it is possible to maintain smooth rotation of the fixing belt 92 and the ceramic heater 82 over a long period of time.

  As an application example of the present invention, application to an image forming apparatus such as a copying machine or a printer using an electrophotographic method, for example, application to a fixing apparatus that fixes an unfixed toner image carried on a recording paper (paper). is there. Further, there is application to an image forming apparatus such as a copying machine or a printer using an ink jet method, for example, to a fixing device that dries an undried ink image carried on a recording paper (paper).

1 is a schematic configuration diagram showing an image forming apparatus of the present invention. 2 is a side cross-sectional view illustrating a configuration of a fixing device according to Embodiment 1. FIG. It is a figure explaining the structure by which an endless belt is supported. It is the perspective view which looked at the downstream belt guide member from diagonally downward. It is a bottom view of a downstream belt guide member. It is a figure explaining the state where a groove | channel gathers the lubricant apply | coated to the inner peripheral surface of an endless belt in the longitudinal direction center part direction. It is an enlarged view of the downstream belt guide member surface. FIG. 4 is a side sectional view illustrating a configuration of a fixing device according to a second embodiment.

Explanation of symbols

1Y, 1M, 1C, 1K ... image forming unit, 11 ... photosensitive drum, 12 ... charger, 13 ... laser exposure device, 14 ... developing device, 15 ... intermediate transfer belt, 16 ... primary transfer roll, 17 ... drum cleaner , 20 ... secondary transfer section, 60, 90 ... fixing device, 61 ... fixing roll, 62 ... endless belt, 63a, 93a ... upstream side belt guide member, 63b, 93b ... downstream side belt guide member, 631 ... groove, 632 ... convex portion, 64 ... pressure pad, 64a ... pre-nip member, 64b ... peeling nip member, 65 ... holder, 66 ... halogen heater, 67 ... lubricant application member, 68 ... low friction sheet, 69 ... temperature sensor, 70 ... peeling Auxiliary member, 80 ... edge guide member, 801 ... belt travel guide part, 802 ... flange part, 803 ... holding part, 82 ... ceramic heater, 91 ... pressure roll 92 ... fixing belt

Claims (7)

A fixing device for fixing a toner image carried on a recording material,
A rotating member;
A belt member that is rotatable while being in contact with the rotating member;
A pressure member that is disposed inside the belt member and that presses the belt member against the rotating member to form a nip portion through which the recording material passes between the rotating member and the belt member;
A lubricant application member disposed to contact the inner peripheral surface of the belt member, and supplying a lubricant to the inner peripheral surface of the belt member;
The belt member is supported from the inside in a region along the direction of both ends from the center in the width direction of the belt member, and the belt member is in contact with the belt member in a region from the pressure member toward the lubricant application member. Plurally formed on the abutment surface by being inclined in the central direction in the width direction of the belt member from the upstream side to the downstream side in the rotation direction of the belt member over substantially the entire longitudinal direction of the abutment surface. A belt guide member having a groove of
Fixing apparatus characterized by comprising a. The belt guide member, the belt member along a rotational direction of having a surface facing downward in the gravity direction from the pressure member side, of claim 1, wherein said groove is equal to or formed on the surface Fixing device.   The fixing device according to claim 1, wherein the belt guide member has a side surface of the groove formed by an inclined surface.   The fixing device according to claim 1, wherein the belt guide member has a curved upper surface edge of the groove.   The fixing device according to claim 1, wherein the belt guide member has a cross-sectional shape of the groove formed in a triangular shape.   The fixing device according to claim 1, further comprising a heating member that heats the rotating member or a heating member that heats the belt member. Toner image forming means for forming a toner image;
Transfer means for transferring the toner image formed by the toner image forming means onto a recording material;
Fixing means for fixing the toner image transferred onto the recording material to the recording material,
The fixing means is
A rotating member;
A belt member that is rotatable while being in contact with the rotating member;
A pressure member that is disposed inside the belt member and that presses the belt member against the rotating member to form a nip portion through which the recording material passes between the rotating member and the belt member;
A lubricant application member disposed to contact the inner peripheral surface of the belt member, and supplying a lubricant to the inner peripheral surface of the belt member;
The belt member is supported from the inside in a region along the direction of both ends from the center in the width direction of the belt member, and the belt member is in contact with the belt member in a region from the pressure member toward the lubricant application member. Plurally formed on the abutment surface by being inclined in the central direction in the width direction of the belt member from the upstream side to the downstream side in the rotation direction of the belt member over substantially the entire longitudinal direction of the abutment surface. An image forming apparatus comprising: a belt guide member having a plurality of grooves .

Images