Fixing device
Patent Information
- Application Number
- JP2022028871
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-02-28
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2042-02-28
AI Technical Summary
The issue of oil leakage from the inner circumferential surface of the fixing belt adhering to the sliding member and subsequently transferring to the outer surface, leading to reduced image quality in image forming apparatuses, is addressed.
The fixing device incorporates a rotatable endless fixing belt with a lubricant applied to its inner surface and a sliding member featuring protrusions, ensuring the belt ends are positioned outside the area where these protrusions are formed, thereby preventing oil from reaching the outer surface.
This configuration effectively reduces oil adhesion to the outer peripheral surface of the fixing belt, thereby maintaining image quality by preventing oil transfer to the recording material.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a fixing device for fixing a toner image onto a recording material. [Background technology]
[0002] The image forming apparatus has a fixing device that fixes the unfixed toner image on the recording material to the recording material.
[0003] A known fixing device has a configuration including a heating roller with a heat source for heating an unfixed toner image, an endless rotatable fixing belt to which heat is applied from the heating roller, and a pressure roller that applies pressure to the fixing belt (Patent Document 1). The heating roller is disposed on the inner circumferential surface of the fixing belt and suspends the fixing belt. The pressure roller is disposed on the outer circumferential surface of the fixing belt and forms a nip with the fixing belt by applying pressure to a pad member via the fixing belt. A recording material bearing an unfixed toner image is conveyed to this nip and, when sandwiched and conveyed in the nip, heat and pressure are applied, fixing the toner on the recording material.
[0004] It is known that in the fixing device using the fixing belt described above, steering control is performed to adjust the position of the fixing belt in the width direction. Steering control prevents scratches on the edge of the recording material and prevents the fixing belt from coming off the member that suspends the fixing belt.
[0005] As printing speeds of image forming devices increase, fixing devices with wider fixing nip widths in the conveyance direction of the recording material are being proposed. Widening the fixing nip width is advantageous for accommodating higher speeds. However, widening the nip width increases the sliding resistance between the pad member and the fixing belt. To address this issue, a known configuration reduces the sliding resistance by applying a lubricant to the inner circumferential surface of the fixing belt and by using a sliding member to improve the sliding properties between the fixing belt and the pad member. [Prior art documents] [Patent documents]
[0006] [Patent Document 1] Patent Publication No. 2003-195671 Summary of the Invention [Problem to be solved by the invention]
[0007] The fixing belt was configured to be shorter in the width direction than the sliding members. As a result, oil leaking from the inner circumferential surface of the belt would adhere to the sliding members on the outside of the fixing belt. When steering control was performed, there was a risk that the oil adhering to the sliding members would then adhere to the outer circumferential surface of the fixing belt. The oil adhering to the outer circumferential surface of the fixing belt would then be transferred to the recording material, causing a decrease in image quality.
[0008] Therefore, an object of the fixing device according to the present invention is to suppress the deterioration of image quality that occurs when oil is transferred to the recording material. [Means for solving the problem]
[0009] In view of the above problems, a fixing device according to the present invention includes a rotatable endless fixing belt, a heating roller that contacts the inner peripheral surface of the fixing belt and applies heat to the fixing belt, a steering roller that contacts the inner peripheral surface of the fixing belt together with the heating roller and changes the position of the fixing belt in the width direction of the fixing belt, a pressure rotor that presses the fixing belt and forms a nip portion together with the fixing belt, a sliding member that contacts the inner peripheral surface of the fixing belt and is slidable against the inner peripheral surface of the fixing belt, and a fixing device that sandwiches and transports a recording material carrying unfixed toner through the nip portion and fixes the unfixed toner image to the recording material, wherein a lubricant is applied to the inner peripheral surface of the fixing belt, and the sliding member has a plurality of protrusions that slide against the fixing belt, and when the nip portion is formed, both ends of the fixing belt in the width direction are located outside the area where the protrusions are formed. [Effects of the Invention]
[0010] According to the fixing device of the present invention, it is possible to reduce the amount of oil adhering to the outer peripheral surface of the fixing belt and to prevent deterioration of image quality. [Brief explanation of the drawings]
[0011] [Figure 1] 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of a fixing device according to the present embodiment. [Figure 3] FIG. 2 is a perspective view of a fixing device according to the embodiment. [Figure 4] FIG. 2 is a view of the fixing device according to the present embodiment as viewed from the transport direction. [Figure 5] FIG. 2 is a schematic view of a sliding member according to the present embodiment. [Figure 6] 3 is a schematic diagram of a nip portion including a sliding member in the present embodiment. FIG. [Figure 7] 3 is a schematic diagram of a nip portion including a sliding member in the present embodiment. FIG. [Figure 8] 10 is a schematic diagram of a nip portion including a sliding member according to a modified example. DETAILED DESCRIPTION OF THE INVENTION
[0012] The image forming apparatus according to the present embodiment will be described below with reference to the drawings. Note that, although the following describes an example in which the present invention is applied to an electrophotographic full-color image forming apparatus having multiple photosensitive drums, the present invention is not limited to this and can also be applied to a monochrome image forming apparatus.
[0013] <Image forming device> The schematic configuration of an image forming apparatus 100 according to this embodiment will be described with reference to FIG.
[0014] 1 is a diagram showing a full-color image forming apparatus according to this embodiment. Image forming apparatus 100 has four types of image forming units 110 arranged along the direction of movement of intermediate transfer belt 115: yellow image forming unit 120a, magenta image forming unit 120b, cyan image forming unit 120c, and black image forming unit 120d. First, the process of forming a toner image on intermediate transfer belt 115 will be described using yellow image forming unit 120a as an example.
[0015] In FIG. 1, the surface of the photosensitive drum 111, which is driven to rotate, is uniformly charged by a charger 112 (charging). Then, an exposure device 113 irradiates the surface of the photosensitive drum 111 with a laser beam according to input image data, forming an electrostatic latent image on the surface of the photosensitive drum 111 (exposure). Then, a developing device 114 forms a yellow toner image on the photosensitive drum 111. A primary transfer roller 117 applies a voltage of a polarity opposite to the potential polarity of the yellow toner image to the intermediate transfer belt 115. This transfers the yellow toner on the photosensitive drum 111 to the intermediate transfer belt 115 (primary transfer). Any remaining yellow toner on the surface of the photosensitive drum 111 without being transferred is scraped off by a toner cleaner and removed from the surface of the photosensitive drum 111. This series of processes is similarly performed in the magenta image forming unit 120b, the cyan image forming unit 120c, and the black image forming unit 120d. As a result, a full-color toner image is formed on the intermediate transfer belt.
[0016] The toner image on the intermediate transfer belt 115 is transported to a secondary transfer portion N2 formed by a secondary transfer roller 116. In synchronization with the transport timing of the toner image, recording materials P are taken out one by one from the recording material cassette 103 and fed to the secondary transfer portion N2. Then, the toner image on the intermediate transfer belt 115 is transferred onto the recording material P (secondary transfer).
[0017] The recording material P onto which the toner image has been transferred is conveyed to the fixing device 200, where it is fixed by heat and pressure (fixing). The recording material P onto which the toner image has been fixed is discharged onto a paper discharge tray.
[0018] The image forming apparatus 100 can also form monochrome images. When forming monochrome images, only the black image forming unit 120d of the multiple image forming units 110 is driven.
[0019] When forming images on both sides of a recording material P, once the transfer and fixing of toner on the first side (first surface) of the image formation is completed, the recording material P is guided to a conveying path 134 by a flapper 132 provided inside the image forming apparatus after fixing. The recording material P is then conveyed to a reversing unit 136. When a reversing sensor 135 detects the trailing end of the recording material P, a flapper 133 switches the conveying direction of the recording material P to a reversing path 137. The image forming apparatus 100 conveys the reversed recording material P again via the reversing path 137 to the image forming unit 110 and further to the fixing device 200. After printing on both sides, the recording material P is guided by the flapper 132 to a discharge path 139 and discharged to the outside.
[0020] The process from charging to discharging the recording material P with the fixed toner image onto the paper output tray is called an image forming process (print job). The period during which image formation is being performed is called an image forming process (print job).
[0021] The operation unit 180 includes a display screen and selection keys. The operation unit 180 displays the status of the image forming apparatus 100 on the display screen and accepts operation instructions from an operator (user) using the selection keys.
[0022] The control board 150 has a control unit 151 and a memory 152, and controls each unit within the image forming apparatus 100 described above. The control unit 151 outputs an output signal to each electrical component to operate the electrical component at the desired timing and with the required amount of control, based on detection signals input from each sensor and information stored in the memory 152. Therefore, it is the control unit 151 that actually controls the electrical components. The memory 152 stores information data required for controlling each unit, and the control unit 151 reads and writes the information data stored in the memory 152.
[0023] <Fixing device> Next, the configuration of the fixing device according to this embodiment will be described in detail with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view of the fixing device according to this embodiment of the present invention, and FIG. 3 is a partial perspective view of the fixing device 200. FIG. 2 shows a schematic diagram of the overall configuration of the belt-heating fixing device 200 according to this embodiment. In FIG. 2, the recording material P is conveyed from right to left on the paper. The fixing device 200 has a heating unit 210 having a heat source and a pressure rotating member (hereinafter referred to as a pressure roller) 202 that forms a nip N together with the heating unit 210. The heating unit 210 has a fixing belt (hereinafter referred to as a belt) 201 as an endless, rotatable heating rotating member, a pad member (hereinafter referred to as a pad) 203 as a fixing member, a heating roller 204, and a steering roller 205.
[0024] Belt 201 has thermal conductivity, heat resistance, and the like, and is a thin-walled cylindrical shape. In this embodiment, it has a three-layer structure consisting of a base layer, an elastic layer on the outer periphery of the base layer, and a release layer on the outer periphery of the elastic layer. The base layer is 60 μm thick and made of polyimide resin (PI), the elastic layer is 300 μm thick and made of silicone rubber, and the release layer is 30 μm thick and made of PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin) as a fluororesin. Belt 201 is stretched by pad 203, heating roller 204, and steering roller 205.
[0025] The pad 203 is a member that comes into pressure contact with the pressure roller 202 via the belt 201 to form a nip portion N of a predetermined width in the recording material conveyance direction. Its cross section is nearly rectangular, and it is a member that is long along the width direction of the belt 201. The material of the pad 203 must be heat resistant, and LCP (liquid crystal polymer) resin is used.
[0026] Between the pad 203 and the belt 201, a sliding member 207 and silicone oil S (hereinafter referred to as oil S) as a lubricant are interposed, so that the belt 201 slides smoothly against the pad 203.
[0027] The oil supply roller 208 is formed by impregnating a roll-shaped member with a 100 μm thick nonwoven fabric wound around it with silicone oil. The oil supply roller 208 is pressed against the inner surface of the belt 201 with a force of 3.0 N by a pressure spring 209, and is supported by the frame of the heating unit 210 so as to be rotatable.
[0028] The oil S applied as a lubricant between the pad 203 and the belt 201 deteriorates as the fixing device 200 operates and is reduced due to leakage to the outside. If the oil S between the pad 203 and the belt 201 cannot be retained, the sliding resistance between the pad 203 and the belt 201 increases, which may cause problems such as poor rotation of the belt 201. The contact of the oil supply roller 208 allows the oil S to be supplied to the inner circumferential surface of the belt 201. This allows the oil S to be maintained between the belt 201 and the pad 203 (sliding member 207) for a longer period of time, thereby maintaining stable operation of the fixing device 200. While the fixing device 200 in this embodiment includes the oil supply roller 208, the oil S may be applied to the inner circumferential surface of the belt 201 during manufacturing. In other words, the fixing device 200 may not include the oil supply roller 208.
[0029] A stay 206 is disposed inside the belt 201. The stay 206 is disposed on the opposite side from the sliding member 207, inside the pad 203. The stay 206 is a reinforcing member that backs up the pad 203 and is long and rigid in the width direction of the belt 201. It is made of a 3 mm thick extruded SUS304 material, and its cross section is formed into a hollow, square-shaped shape to ensure strength. When the pad 203 is pressed against the pressure roller 202, the stay 206 provides strength to the pad 203, ensuring the pressure at the nip N. Note that the material of the stay 206 is not limited to stainless steel as long as strength can be ensured.
[0030] The heating roller 204 is a stainless steel pipe with a thickness of 1 mm, and has a halogen heater (not shown) disposed inside it, which is capable of generating heat up to a predetermined temperature. The belt 201 is heated by the heating roller 204, and is controlled to a predetermined target temperature according to the paper type based on temperature detection by a thermistor. The heating roller 204 may also be configured to rotate. By rotating the heating roller 204, it is possible to increase the tension of the belt 201 from the nip portion N to the heating roller 204 in the belt rotation direction. This increases the curvature of the exit of the nip portion N in the belt rotation direction, thereby improving the separation performance of the recording material P.
[0031] The steering roller 205 suspends the belt 201 and is supported by a steering frame 213. When the steering frame 213 rotates relative to the frame of the heating unit 210 around a rotation shaft 212 as a fulcrum, the steering roller 205 changes its alignment with the other suspension members. This generates a tension difference between the front and rear of the belt 201. As a result, as shown in FIG. 4, the position of the belt 201 is controlled by moving the belt 201 in the U direction in the width direction of the belt 201. The steering roller 205 is biased by a spring 211 supported by the steering frame 213, and also serves as a tension roller that applies a predetermined tension to the belt 201.
[0032] The steering roller 205 also plays a role in suppressing uneven gloss caused by the edge of the recording material P. In this embodiment, a force of approximately 2000 N is applied to the belt 201 at the nip N. When unfixed toner is fixed to the recording material, the portion of the belt 201 that comes into contact with the edge of the recording material P is subjected to greater stress than the portion that does not come into contact with the edge. The area where the edge of the recording material has repeatedly passed becomes recessed compared to the non-contact portion of the edge. Such recesses on the surface of the belt 201 caused by the edge of the recording material are called paper edge scratches.
[0033] When fixing unfixed toner to the recording material, the fixing device 200 applies pressure and heat to the recording material. At this time, the surface condition of the belt 201 is reflected in the gloss of the fixed image surface. If the surface of the belt 201 is uneven, the uneven condition is reflected in the gloss of the image surface, resulting in gloss unevenness (gloss unevenness) on the image surface. Therefore, if unfixed toner is fixed to the recording material with scratches on the edge of the belt 201, gloss unevenness like a straight line will occur on the image surface. Therefore, in this embodiment, the belt 201 is moved back and forth in the width direction to prevent scratches on the edge of the belt 201.
[0034] The fixing device 200 in this embodiment has a position detection unit (not shown) that detects the position of the belt 201 in the width direction. An arm is provided at an end of the belt 201, abutting from the outside to the inside of the belt 201 in the width direction. The position of this arm can be determined by detecting the position of this arm with a sensor such as a photointerrupter. To accurately detect the position of the belt 201 in the width direction, the arm applies force to the belt 201 in the direction from the outside to the inside of the belt 201 in the width direction. To apply force in this direction, the arm's rotation axis is perpendicular to the width direction. Therefore, the arm that detects the position of the belt in the width direction rotates in the width direction around the rotation axis. Detecting the position of the belt 201 in the width direction makes it possible to prevent the belt 201 from coming off the components (pad 203, heating roller 204, and steering roller 205) that support the belt 201. Furthermore, the belt 201 can be actively moved in the width direction to prevent edge damage.
[0035] The pressure roller 202 is a roller with an elastic layer formed on the outer periphery of its shaft and a release layer formed on the outer periphery of the elastic layer. The shaft is made of stainless steel, the elastic layer is 5 mm thick and made of conductive silicone rubber, and the release layer is 50 μm thick and made of PFA, a fluororesin. The pressure roller 202 is axially supported by the fixing frame 380 of the fixing device 200, and a gear is fixed to one end of the pressure roller 202, which is connected to a driving source M via the gear and is driven to rotate. The belt 201 is held between the rotating pressure roller 202 and pad 203, and rotates in the R direction.
[0036] <Contact / separation mechanism> The contact / separation mechanism of the pressure roller 202 will now be described. The pressure roller 202 can be moved by the contact / separation mechanism to a position in contact with or separated from the belt 201. The contact / separation mechanism has a pressure frame 202b and a drive motor. The pressure frame 202b supports the pressure roller 202. The pressure frame 202b rotates around a pressure rotation shaft 202a as its rotation axis, driven by the drive motor. When the drive motor rotates the pressure frame 202b around the pressure rotation shaft 202a in a clockwise direction on the paper, the pressure roller 202 moves in the direction of arrow P. As a result, the pressure roller 202 is brought into contact with the pad 203 across the belt 201 in a direction perpendicular to the conveyance direction of the recording material, i.e., in the pressure direction (contact state). This forms a fixing nip N. When the pressure frame 202b is rotated counterclockwise on the paper surface around the pressure rotation shaft 202a as a rotation axis, the pressure roller 202 is separated from the belt 201 (separated state).
[0037] In this way, the pad 203, the heating roller 204, and the steering roller 205 are arranged on the inner circumferential surface of the belt 201, and the belt 201 is suspended thereon. The belt 201 is sandwiched between the pressure roller 202 and the pad 203, and is rotated by the rotation of the pressure roller 202. The belt 201 stores heat from the heating roller 204. When the recording material P carrying an unfixed toner image is sandwiched and conveyed between the pressure roller 202 and the belt 201 at the nip N, the heat and pressure necessary for fixing are applied to the recording material P. Then, the toner image is fixed on the recording material P.
[0038] <Sliding member> The pad 203 is pressed against the pressure roller 202 via the belt 201 to form a fixing nip N. The pad 203 is made of LCP (liquid crystal polymer) resin. A sliding member 207 is interposed between the pad 203 and the belt 201.
[0039] In the fixing device F of this embodiment, the pressure applied to the fixing nip portion N is 1600 N and the nip width is 24.5 mm, so the sliding resistance between the belt 201 and the pad 203 that stretches the belt 201 is large. To reduce the sliding resistance, a sliding member 207 that can slide against the belt 201 is provided on the belt 201 side of the pad 203. Details are described below.
[0040] FIG. 5 shows the detailed configuration of the sliding member 207. FIG. 5(a) is a cross-sectional view of the sliding member 207, with the left-right direction on the paper as the conveying direction (X direction) and the up-down direction as the pressure direction (Z direction). FIG. 5(b) is a view of the sliding member 207, viewed from the pressure roller 202 side, with the left-right direction on the paper as the width direction (Y direction) and the up-down direction as the conveying direction (X direction). As shown in FIG. 3(a), the sliding member 207 of this embodiment is composed of a base member 207a, embossed portions 207b as protrusions, and a sliding layer 207c. The base member 207a only needs to have sufficient heat resistance and strength. Materials such as SUS, copper, aluminum, and engineering plastics (PI, PEEK, LCP, etc.) are desirable. In this embodiment, the sliding member 207 has embossments spaced at equal intervals in the width direction, with a distance d between the embossments (the distance between the protrusions) of 1.4 mm. By providing the embossed portion 207b, the contact area with the belt 201 is reduced, thereby reducing sliding resistance. In this embodiment, the base material 207a and the embossed portion 207b are made of SUS, which is a metal. However, it is not limited to SUS, and any metal with excellent heat resistance and durability is preferable.
[0041] It is preferable to provide the sliding layer 207c with a material (fluorine coating, PTFE, PFA, etc.) to achieve low friction. In this example, a 20 μm thick PTFE (polytetrafluoroethylene) coating was used. As mentioned above, the friction force between the inner circumferential surface of the belt 201 and the sliding member 207 is very large, so by further applying a lubricant, the belt 201 can slide smoothly against the sliding member 207. Silicone oil was used as the lubricant.
[0042] The sliding member 207 of this embodiment is configured to cover the pad 203 regardless of whether it is inside or outside the nip portion N. Although not shown here, it is acceptable as long as part of the fixing nip portion N is covered by the sliding member 207. In other words, it is acceptable to have a configuration in which the sliding member 207 is disposed only in the nip portion N.
[0043] In this embodiment, the embossed portion 207b of the sliding member is provided over the entire area of the sliding member 207. Although not shown here, it is acceptable as long as part of the fixing nip portion N is covered with the embossed portion 207b of the sliding member. In other words, it is acceptable to have a configuration in which the embossed portion 207b of the sliding member is disposed only in the nip portion N. The embossed portion 207b provided in the nip portion N is configured to abut against the belt 201 via the sliding layer 207c.
[0044] In this embodiment, a configuration is adopted in which the sliding member 207 is fixed to the stay 206. (Not shown) Although not shown hereinafter, the sliding member 207 and the pad 203 may be integrated. Also, a portion of the sliding member 207 may be fixed to the stay 206 or the pad 203. For example, both ends of the sliding member 207 in the Y direction (width direction) may be fixed to the pad 203 with screws or the like.
[0045] In this embodiment, the pressure applied to the fixing nip portion N is 1600 N, and the length of the fixing nip portion N in the conveying direction is 24.5 mm and the length in the width direction is 326 mm.
[0046] <Deterioration of image quality due to lubricants> In the fixing device 200 using the belt 201 as in this embodiment, a lubricant, oil S, is used. The oil S is applied to the inner peripheral surface of the belt 201. At the nip portion N, a pressure is generated by the pad 203 and the pressure roller 202, so that a force is exerted from the inner peripheral surface of the belt 201 on the oil S applied to the inner peripheral surface of the belt 201. If the belt 201 is configured to be shorter in the width direction than the sliding member 207 and the pad 203, the pushed-out oil S may run along the sliding member 207 and the pad 203 and adhere to the outer peripheral surface of the belt 201.
[0047] In this embodiment, the belt 201 is reciprocated in the width direction using a steering roller 205. If oil S is exposed in the outer region of the belt 201, the oil S will significantly adhere to the outer surface of the belt 201. Because the belt 201 rotates in the direction R in FIG. 2, the oil S adhering to the outer surface of the belt 201 will reach the nip portion N. If the oil S adheres to the recording material P conveyed to the nip portion N, the region where the oil S adheres will result in a defective image. Therefore, it is necessary to prevent the oil S from adhering to the region of the belt 201 that comes into contact with the recording material S.
[0048] Before reaching the outer surface of belt 201, oil S flows down the unevenness provided on sliding member 207 from the inner circumferential surface of belt 201. For this reason, in fixing device 200 of this embodiment, belt 201 is configured to be longer in the width direction than the region where embossed portion 207 is provided. Details of this are described below.
[0049] <Relationship between the length of the belt and the sliding member> The relationship in the width direction will be described using Figure 6. Figure 6 is a diagram showing one end of fixing device 200 including belt 201, pad 203, and sliding member 207. The left-right direction on the paper surface of Figure 6 is the width direction. The other end has the same relationship, so the description will be omitted.
[0050] The sliding member 207 has an area where the embossed portions 207b are provided, and a non-installation area 207e on the outer side in the width direction of the area where the embossed portions 207b are provided, where the embossed portions 207b are not provided.
[0051] As shown in FIG. 6, the belt 201 is configured to be longer in the width direction than the area of the sliding member 207 where the embossed portion 207b is provided.
[0052] Oil S applied between the inner circumferential surface of belt 201 and embossed portion 207b leaks out beyond the area where embossed portion 207b is provided. However, since belt 201 is long in the width direction, oil S that leaks out beyond the area where embossed portion 207b is provided is unlikely to reach the outer surface of belt 201. Therefore, oil S is more likely to be maintained on the inner circumferential surface of belt 201, and adhesion of oil S to the outer surface of belt 201 can be suppressed.
[0053] Furthermore, the belt 201 and the pad 203 are in contact with each other at the exit of the nip portion N. Therefore, if the oil S adheres to the pad 203, there is a risk that the oil S will run down the pad 203 and adhere to the outer surface of the belt 201. For this reason, in this embodiment, as shown in FIG. 6, the belt 201 is configured to be longer than the pad 203 in the width direction.
[0054] In this embodiment, a steering roller 205 is used. The position of end 207g of belt 201 in the width direction is changed by steering roller 205. However, as shown in FIG. 7 , even when end 207g of belt 201 is changed by steering roller 205, end 207g of belt 201 is positioned outside embossed portion 207b in the width direction. This prevents oil S from adhering to the outer surface of belt 201, even in a fixing device 200 having a steering roller 205. In this configuration, oil S leaking from embossed portion 207b accumulates in non-contact area 207e. However, the oil S accumulated in non-contact area 207e is pulled back toward the inside of belt 201 in the width direction due to surface tension. As a result, oil S is resupplied from non-contact area 207e, preventing oil S from adhering to the outer surface of belt 201.
[0055] The position of end 201g of belt 201 in the width direction is changed by steering roller 205. However, as a modified example shown in Fig. 8, even when end 201g of belt 201 is changed by steering control, end 201g of belt 201 may be configured to be positioned outside end 203g of pad and end 207g of sliding member 207. This makes it possible to prevent oil S from running down pad 203 and sliding member 207 and adhering to the outer surface of belt 201.
[0056] In this embodiment, the sliding member 207 is fixed to the stay 206 with screws or the like. The screw insertion areas are provided at both ends of the sliding member 207 in the width direction. Therefore, the length in the width direction including the sliding member 207 and the screw insertion areas is longer than the length of the belt 201. However, the screw insertion areas are not limited to both ends in the width direction, and may be both ends in the conveying direction. In other words, the screw insertion areas are not included in the non-installation area 207e. [Explanation of symbols]
[0057] 100 Image forming device 200 Fixing device 201 Fixing belt 202 Pressure roller 203 Pad 204 Heating Rotary Body 205 Steering roller 206 Stay 207 Sliding members
Claims
1. A rotatable endless fixing belt; a heating roller that contacts an inner circumferential surface of the fixing belt and applies heat to the fixing belt; a steering roller that contacts an inner peripheral surface of the fixing belt together with the heating roller and changes a position of the fixing belt in a width direction of the fixing belt; a pressure rotating body that applies pressure to the fixing belt and forms a nip portion together with the fixing belt; a sliding member that is in contact with an inner circumferential surface of the fixing belt and is slidable against the inner circumferential surface of the fixing belt; A fixing device in which a recording material carrying unfixed toner is nipped and conveyed through the nip portion, and an unfixed toner image is fixed onto the recording material, A lubricant is applied to the inner peripheral surface of the fixing belt, the sliding member has a plurality of protrusions that slide against the fixing belt, a fixing belt having a nip portion formed therein, the protrusions being formed on the protruding portions of the fixing belt, the protruding portions being located on the outer side of the protruding portions;
2. The fixing device according to claim 1 , further comprising a pad member that holds the sliding member and that forms a nip portion by sandwiching the fixing belt together with the pressure rotating body.
3. 3. The fixing device according to claim 2, wherein, in a state where the nip portion is formed, the length of the pad member in the width direction is shorter than the length of the fixing belt in the width direction.
4. 4. The fixing device according to claim 1, wherein, in a state in which the nip portion is formed, both end portions of the fixing belt are positioned outside the pressure rotating member in the width direction.
5. 5. The fixing device according to claim 1, wherein the sliding member has, in the width direction, a non-installation area outside an area where the protrusions are formed, which is an area where the protrusions are not provided.
6. A rotatable, endless fixing belt that applies heat to a recording material; a steering roller that contacts an inner circumferential surface of the fixing belt and swings to change a position of the fixing belt in a width direction of the fixing belt; a sliding member that is in contact with an inner circumferential surface of the fixing belt and is slidable against the inner circumferential surface of the fixing belt; a pressure rotating body disposed opposite the sliding member with the fixing belt interposed therebetween and pressing the fixing belt to form a nip portion; A fixing device in which a recording material carrying unfixed toner is nipped and conveyed through the nip portion, and an unfixed toner image is fixed onto the recording material, A lubricant is applied to the inner peripheral surface of the fixing belt, During operation of the steering roller, An end of the fixing belt on one end side in the width direction can be located outside the end of the sliding member on the one end side, or inside the end of the sliding member on the one end side. A fixing device comprising:
7. The sliding member has an area in which a plurality of protrusions are formed, During operation of the steering roller, The fixing device according to claim 6 , wherein an end of the fixing belt on one end in the width direction is positioned outside an end of the region on the one end.
8. The sliding member has a non-forming region in which the protrusion is not formed outside the region in the width direction, During operation of the steering roller, An end of the fixing belt on one end in the width direction can be located outside the end of the non-forming region on the one end, or inside the end of the non-forming region on the one end.
8. The fixing device according to claim 7,
9. A pad member that holds the sliding member and that forms the nip portion by sandwiching the fixing belt together with the pressure rotating body.
7. The fixing device according to claim 6, 10. The steering roller according to claim 1, wherein: An end of the fixing belt on one end side in the width direction is positioned outside an end of the pressure rotating body on the one end side.
7. The fixing device according to claim 6.
11. The lubricant is an oil.
7. The fixing device according to claim 6,
12. Having an oil application roller for applying the oil. The fixing device according to claim 11 .
13. A rotatable, endless fixing belt for applying heat to a recording material; a steering roller that contacts an inner circumferential surface of the fixing belt and swings to change a position of the fixing belt in a width direction of the fixing belt; a sliding member that is in contact with an inner circumferential surface of the fixing belt and is slidable against the inner circumferential surface of the fixing belt; a pressure rotating body disposed opposite the sliding member with the fixing belt interposed therebetween and pressing the fixing belt to form a nip portion; A fixing device in which a recording material carrying unfixed toner is nipped and conveyed through the nip portion, and an unfixed toner image is fixed onto the recording material, A lubricant is applied to the inner peripheral surface of the fixing belt, Regardless of the operation of the steering roller, An end portion of the fixing belt on one end side in the width direction is positioned outside an end portion of the sliding member on the one end side. A fixing device comprising:
14. A pad member that holds the sliding member and that sandwiches the fixing belt together with the pressure rotating body to form the nip portion. The fixing device according to claim 13 .
15. Regardless of the operation of the steering roller, An end of the fixing belt on one end side in the width direction is positioned outside an end of the pressure rotating body on the one end side. The fixing device according to claim 13 .
16. The lubricant is an oil. The fixing device according to claim 13 .
17. Having an oil application roller for applying the oil. The fixing device according to claim 16 .