Fixing apparatus and image forming apparatus

Abstract

The purpose is to prevent damage and wear to the annular belt and contact members. [Solution] The fixing device 10 includes a fixing belt 11 as a rotatable annular belt, a sliding ring 40 as a contact member that can contact the end of the fixing belt 11, and a driving force transmission unit 7 that transmits driving force to the sliding ring 40 and controls the rotational speed of the sliding ring 40 in relation to the rotational speed of the fixing belt 11.

Description

Technical Field

[0001] The present disclosure relates to a fixing device that fixes an image onto a medium, and an image forming apparatus including the fixing device.

Background Art

[0002] Some fixing devices used in electrophotographic image forming apparatuses include an endless belt. For example, Patent Document 1 discloses a fixing device in which contact members (for example, sliding rings) are arranged on both sides in the width direction of the endless belt. The contact members contact the ends of the endless belt and rotate together with the endless belt.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the contact state between the endless belt and the contact member changes, the rotation of the contact member may become unstable. When the rotation of the contact member becomes unstable, there is a possibility that the endless belt and the contact member may be damaged (including wear).

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to prevent damage to the endless belt and the contact member.

Means for Solving the Problems

[0006] The fixing device of the present disclosure is characterized by including a rotatable endless belt, a contact member that can contact the end of the endless belt, and a driving force transmission unit that transmits a driving force to the contact member and controls the rotation speed of the contact member with respect to the rotation speed of the endless belt.

[0007] The image forming apparatus disclosed herein comprises an image forming unit that forms an image on a medium, and a fixing device that fixes the image formed by the image forming unit onto the medium. [Effects of the Invention]

[0008] According to this disclosure, since the rotational speed of the contact member is controlled by the drive force transmission unit relative to the rotational speed of the annular belt, the rotation of the contact member can be stabilized, and as a result, damage and wear of the annular belt and the contact member can be prevented. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the basic configuration of the image forming apparatus according to Embodiment 1. [Figure 2] This is a cross-sectional view showing the fixing device of Embodiment 1. [Figure 3] This is a perspective view showing the fixing device of Embodiment 1. [Figure 4] This is a perspective view showing the fixing device of Embodiment 1 with the fixing belt and upper cover removed. [Figure 5] This is a perspective view showing the main parts of the fixing device of Embodiment 1. [Figure 6] This is a perspective view showing the main parts of the fixing device of Embodiment 1 with the fixing belt removed. [Figure 7] This is a front view showing the main parts of the fixing device of Embodiment 1. [Figure 8] These are perspective views (A), front views (B), and side views (C) showing the flange member of Embodiment 1. [Figure 9] (A) is a perspective view showing the sliding ring of Embodiment 1, and (B) is a schematic diagram showing the sliding ring attached to the flange member. [Figure 10] This is a cross-sectional view of the main part of the fixing device at line segment 10-10 shown in Figure 7. [Figure 11] This is a cross-sectional view of the main part of the fixing device at line segment 11-11 shown in Figure 7. [Figure 12]It is a schematic diagram showing the fixing belt of Embodiment 1, each part of the driving force transmission part, and the rotation direction of the sliding ring. [Figure 13] It is a cross-sectional view showing the main part of the fixing device of Embodiment 2. [Figure 14] It is a cross-sectional view showing a part of the main part of the fixing device of Embodiment 2 in an enlarged manner. [Figure 15] It is a front view showing another configuration example of the main part of the fixing device.

Embodiments for Carrying out the Invention

[0010] Embodiment 1. <Image forming apparatus 1> The image forming apparatus 1 provided with the fixing device 10 of Embodiment 1 will be described. FIG. 1 is a diagram showing the configuration of the image forming apparatus 1 of Embodiment 1. The image forming apparatus 1 forms an image using the electrophotographic method, and here it is a color printer. However, the image forming apparatus 1 may be a monochrome printer, or may be a copier, a facsimile machine, a multifunction machine, etc.

[0011] The image forming apparatus 1 includes a medium supply unit 110 that supplies a medium P such as printing paper, process units 80K, 80Y, 80M, 80C as an image forming unit that forms an image, a transfer unit 90 that fixes the image on the medium P, a fixing device 10 that fixes the image on the medium P, a medium discharge unit 120 that discharges the medium P to the outside of the image forming apparatus 1, and a housing 100 that houses these. The upper part of the housing 100 is covered with an openable and closable top cover 102.

[0012] The medium supply unit 110 includes a paper feed tray 111 as a medium storage unit that stores the medium P in a stacked state, a pickup roller 112 that pulls out the medium P stacked on the paper feed tray 111 one by one, feed rollers 113 and retard rollers 114 that send out the pulled-out medium P to a conveyance path, and conveyance roller pairs 115 and 116 that convey the medium P sent out to the conveyance path to the transfer unit 90.

[0013] The process units 80K, 80Y, 80M, and 80C are arranged in a row along the conveyance path of the medium P (here, from right to left in FIG. 1). The process units 80K, 80Y, 80M, and 80C form toner images with black, yellow, magenta, and cyan toners (developers), respectively. Since the process units 80K, 80Y, 80M, and 80C have a common configuration except for the toner, they are described as "process unit 80".

[0014] The process unit 80 includes a photosensitive drum 81 as an image carrier, a charging roller 82 as a charging member, a developing roller 84 as a developer carrier, a supply roller 85 as a supply member, a cleaning member 86, and a toner cartridge 87 as a developer container. Further, a print head 83 as an exposure device is suspended from the top cover 102 so as to face the photosensitive drum 81.

[0015] The photosensitive drum 81 is a cylindrical member provided with a photosensitive layer (charge generation layer and charge transport layer) on the surface of a conductive substrate, and rotates clockwise in FIG. 1 by the driving force of a driving motor.

[0016] The charging roller 82 is arranged to contact the surface of the photosensitive drum 81 and rotates following the rotation of the photosensitive drum 81. The charging roller 82 is applied with a charging voltage by a charging voltage power source to uniformly charge the surface of the photosensitive drum 81.

[0017] The print head 83 includes a light emitting element array in which light emitting elements such as LEDs (light emitting diodes) are arranged, and a lens array that condenses the emitted light of the light emitting elements on the surface of the photosensitive drum 81. The print head 83 exposes the surface of the photosensitive drum 81 to form an electrostatic latent image.

[0018] The developing roller 84 is positioned to contact the surface of the photoreceptor drum 81 and rotates in the opposite direction to the photoreceptor drum 81 (counterclockwise in Figure 1). The developing roller 84 is subjected to a developing voltage by a developing voltage power supply, and toner is deposited onto the electrostatic latent image formed on the surface of the photoreceptor drum 81, thereby forming a toner image.

[0019] The supply roller 85 is positioned to contact or face the surface of the developing roller 84 and rotates in the same direction as the developing roller 84 (counterclockwise in Figure 1). The supply roller 85 is supplied with a supply voltage by a supply voltage power supply and supplies toner to the developing roller 84.

[0020] The cleaning member 86 is a blade or roller made of an elastic material such as urethane rubber, and is pressed against the surface of the photoreceptor drum 81. The cleaning member 86 removes toner remaining on the surface of the photoreceptor drum 81 after the toner image has been transferred.

[0021] The toner cartridge 87 is detachably attached to the main body of the process unit 80. The toner cartridge 87 contains toner as a developer and supplies toner to the developing roller 84 and the supply roller 85.

[0022] The transfer unit 90 includes a transfer roller 91 as a transfer member positioned opposite each photoreceptor drum 81 of the process units 80K, 80Y, 80M, and 80C, a transfer belt 92 that passes between the photoreceptor drum 81 and the transfer roller 91, and a drive roller 93 and a tension roller 94 over which the transfer belt 92 is stretched.

[0023] The drive roller 93 rotates due to the driving force of the belt drive motor, causing the transfer belt 92 to move. The transfer belt 92 moves while holding the medium P on its surface by electrostatic force. The tension roller 94 applies tension to the transfer belt 92. The transfer roller 91 is supplied with a transfer voltage by the transfer voltage power supply and transfers the toner image on each photoreceptor drum 81 to the medium P on the transfer belt 92.

[0024] The fixing unit 10 is located downstream of the process units 80K, 80Y, 80M, and 80C along the transport path of the medium P. The fixing unit 10 applies heat and pressure to the medium P onto which the toner image has been transferred, thereby fixing the toner image to the medium P. The specific configuration of the fixing unit 10 will be described later.

[0025] The media discharge section 120 is located downstream of the fixing device 10 along the transport path of the media P. The media discharge section 120 has pairs of discharge rollers 121, 122, and 123 that discharge the media P that has passed through the fixing device 10 to the outside of the image forming apparatus 1. The top cover 102 of the image forming apparatus 1 is provided with a stacker section 124 for placing the discharged media P.

[0026] In Figure 1, the transport direction (direction of movement of the medium P) when the medium P passes through the fixing device 10 is defined as the Y direction. The width direction of the medium P transported in the Y direction is defined as the X direction. The X direction is parallel to the rotation axis of the photoreceptor drum 81. The direction perpendicular to the Y and X directions is defined as the Z direction.

[0027] For the Y direction, the transport direction when the medium P passes through the fixing device 10 is defined as the +Y direction, and the opposite direction is defined as the -Y direction. For the X direction, when facing the +Y direction, the direction to the right is defined as the +X direction, and the direction to the left is defined as the -X direction. For the Z direction, the upward direction in Figure 1 is defined as the +Z direction, and the downward direction is defined as the -Z direction.

[0028] <Fusing device 10> Figure 2 is a cross-sectional view showing the fixing device 10. The fixing device 10 comprises a fixing belt 11 as an annular belt (endless belt), a heater 15 positioned on the inner circumference side of the fixing belt 11, and a pressure roller 20 as a pressure member positioned on the outer circumference side of the fixing belt 11.

[0029] The width direction of the fixing belt 11 is the X direction. The fixing belt 11 has, for example, a base layer made of a metal such as stainless steel, an elastic layer such as silicone rubber formed on the surface of the base layer, and a coating layer such as PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) formed on the surface of the elastic layer.

[0030] The pressure roller 20 is positioned, for example, below the fixing belt 11 (in the -Z direction) so as to contact the outer circumferential surface of the fixing belt 11. The axial direction of the pressure roller 20 is the X direction. The pressure roller 20 has, for example, a metal shaft 21, an elastic layer 22 made of silicone rubber or the like formed on the surface of the shaft 21, and a coating layer 23 made of PFA or the like formed on the surface of the elastic layer 22.

[0031] The pressure roller 20 forms a fixing nip with the fixing belt 11 and rotates in the direction indicated by arrow R0 (for example, counterclockwise) due to rotational transmission from a fixing motor (not shown). The fixing belt 11 rotates in the opposite direction to the rotation of the pressure roller 20 (in the direction indicated by arrow R1) due to contact with the pressure roller 20.

[0032] On the inner circumference of the fixing belt 11, a stay 12, a heater support member 13, a heat conduction member 14, a heater 15, a heat diffusion member 16, and a temperature sensor 17 are arranged.

[0033] The stay 12 is a member that is long in the X direction and has a roughly U-shaped cross-section in a plane perpendicular to the X direction. More specifically, the stay 12 has two side plate portions 12b that are opposite each other in the Y direction and a top plate portion 12a that connects the upper ends of the side plate portions 12b. The stay 12 is a structural component that supports the heater support member 13, the heat conduction member 14, the heater 15, the heat diffusion member 16, and the temperature sensor 17. The stay 12 is made of a metal such as electro-galvanized steel sheet.

[0034] The heater support member 13 is fixed to the lower side (-Z direction) of the stay 12. The heater support member 13 is attached to the stay 12 and supports the heater 15. The heater support member 13 has two side plate portions 13b that are fixed inside the two side plate portions 12b of the stay 12, and a bottom plate portion 13a that connects the lower ends of the side plate portions 13b.

[0035] The lower surface (-Z direction surface) of the bottom plate portion 13a of the heater support member 13 is in contact with the heat conduction member 14, which will be described next. Grooves 13d, which are long in the X direction, are formed at both ends of the bottom plate portion 13a in the Y direction. The heater support member 13 is made of a resin such as PEEK (polyether ether ketone).

[0036] The heat conduction member 14 is, for example, a plate-shaped member and is positioned between the heater support member 13 and the heater 15, which will be described next. The heat conduction member 14 is made of a material with high heat resistance and high thermal conductivity, such as stainless steel (SUS). The upper surface (the surface in the +Z direction) of the heat conduction member 14 is in contact with the lower surface of the bottom plate portion 13a of the heater support member 13.

[0037] The heater 15 is a plate-shaped heat source (i.e., a plate-shaped heater) that heats the fixing belt 11. The heater 15 has a resistance wire that acts as a heating element, and generates heat when current is supplied to the resistance wire. The upper surface of the heater 15 is in contact with the lower surface of the heat conductive member 14.

[0038] The heat diffusion member 16 is positioned between the heater 15 and the fixing belt 11, transferring heat from the heater 15 to the fixing belt 11. The heat diffusion member 16 is made of a material with high heat resistance and high thermal conductivity, such as glass-coated stainless steel. The upper surface of the heat diffusion member 16 is in contact with the lower surface of the heater 15, and the lower surface of the heat diffusion member 16 is in contact with the inner circumferential surface of the fixing belt 11.

[0039] The heat diffusion member 16 is a plate-shaped member that is long in the X direction, and both ends in the Y direction are bent upward (towards the heater 15) to form a pair of bent pieces 16a. Each bent piece 16a is inserted into a groove 13d in the bottom plate portion 13a of the heater support member 13 and fixed in place. The heat conduction member 14 and the heater 15 are held in a state where they are sandwiched in the Z direction between the bottom plate portion 13a of the heater support member 13 and the heat diffusion member 16.

[0040] The lower surface of the heat diffusion member 16 (the contact surface that contacts the inner circumferential surface of the fixing belt 11) is coated with grease to reduce the frictional force between it and the inner circumferential surface of the fixing belt 11.

[0041] Furthermore, a temperature sensor 17 is positioned so as to be in contact with the upper surface of the heat conduction member 14. The temperature sensor 17 detects the temperature of the heater 15 via the heat conduction member 14 and is supported by the heater support member 13. The output signal of the temperature sensor 17 is sent to a heater control circuit (not shown), and the temperature of the heater 15 is controlled based on this signal.

[0042] Figure 3 is a perspective view showing the fixing device 10. As shown in Figure 3, the fixing device 10 has a pair of side frames 51 facing each other in the X direction, a base portion 50 that supports the side frames 51 from below (-Z direction), and an upper cover 52 located above the side frames 51 (+Z direction).

[0043] The aforementioned fixing belt 11, stay 12, heater support member 13, heat conduction member 14, heater 15, heat diffusion member 16, temperature sensor 17, and pressure roller 20 are arranged between a pair of side frames 51 in the X direction. The pressure roller 20 is also rotatably supported by the pair of side frames 51.

[0044] Figure 4 is a perspective view showing the fixing device 10 with the fixing belt 11 and upper cover 52 removed. As shown in Figure 4, a pair of swing levers 55 are provided on the inside of the pair of side frames 51 in the X direction.

[0045] Each swing lever 55 is pivotably supported by a pivot shaft 54 ​​in the X direction provided on the side frame 51. The pivot shaft 54 ​​is located at both the lower end (-Z direction end) and the -Y direction end of the swing lever 55. The swing lever 55 has a hole 55a (see Figure 5) that engages with the pivot shaft 54.

[0046] Each oscillating lever 55 is fitted with a flange member 30, which serves as a belt holding member. The flange member 30 supports the anchoring belt 11 (Figure 3) from the inner circumference at the end regions on both sides in the width direction of the anchoring belt 11. In addition, sliding rings 40 are provided as contact members so as to face each end of the anchoring belt 11 in the width direction. Note that in Figures 3 and 4, one of the sliding rings 40 is hidden by the side frame 51.

[0047] Of the fixing device 10, a pair of oscillating levers 55 and the components attached thereto (including the fixing belt 11, stay 12, heater support member 13, heat conduction member 14, heater 15, heat diffusion member 16, and temperature sensor 17) constitute an oscillating unit 18. The oscillating unit 18 and the pressure roller 20 together are referred to as the main part of the fixing device 10.

[0048] Figure 5 is a perspective view showing the main parts of the fixing device 10. Figure 6 is a perspective view showing the main parts of the fixing device 10 shown in Figure 5, with the fixing belt 11 removed. Figure 7 is a front view showing the main parts of the fixing device 10.

[0049] As shown in Figure 6, the X-direction end of the stay 12 is fixed to the flange member 30 attached to each oscillating lever 55. That is, the pair of oscillating levers 55 support the fixing belt 11, stay 12, heater support member 13, heat conduction member 14, heater 15, heat diffusion member 16, and temperature sensor 17 (Figure 2) via the pair of flange members 30.

[0050] A contact plate 57 is provided at the upper end (the end in the +Z direction) and the end in the +Y direction of the oscillating lever 55. The contact plate 57 has an engaging portion 57a ​​that engages with the inside of the coil spring 62 (Figure 4), which will be described next.

[0051] As shown in Figure 4, a coil spring 62 is attached to each side frame 51 as a biasing member. The winding axis direction of the coil spring 62 is the Y direction. The -Y direction end of the coil spring 62 is in contact with the contact plate 57. The +Y direction end of the coil spring 62 is in contact with the wall portion 51a of the side frame 51. As a result, the coil spring 62 biases the contact plate 57 of the swing lever 55 in the +Y direction, as indicated by arrow F in Figure 4.

[0052] On each side frame 51, a cam 60 is positioned on the side opposite the coil spring 62 (i.e., the +X side) relative to the contact plate 57 of the oscillating lever 55. In Figure 4, one of the cams 60 is hidden by the side frame 51. The pair of cams 60 are mounted on a rotating shaft 61 that extends in the X direction between the pair of side frames 51. The outer circumferential surface of the cam 60 is in contact with the side of the contact plate 57 opposite the coil spring 62. That is, the contact plate 57 is pressed against the outer circumferential surface of the cam 60 by the biasing force of the coil spring 62.

[0053] The cam 60 rotates due to rotational transmission from a cam motor (not shown). The rotation of the cam 60 changes the position of the contact plate 57, causing the oscillating lever 55 to swing around the pivot shaft 54 ​​in the directions indicated by arrows C1 and C2 in Figure 4. The swinging of the oscillating lever 55 causes the oscillating unit 18, including the fixing belt 11, to move toward and away from the pressure roller 20.

[0054] The cam 60 presses the contact plate 57 of the swing lever 55 in the -Y direction, causing the swing lever 55 to swing around the pivot shaft 54 ​​in the direction indicated by arrow C1. This causes the fixing belt 11 to move upward away from the pressure roller 20. When no fixing operation is being performed, the fixing belt 11 is positioned upward away from the pressure roller 20 in this manner.

[0055] On the other hand, when the cam 60 rotates by a predetermined angle and the pressure on the contact plate 57 weakens, the oscillating lever 55 swings around the pivot shaft 54 ​​in the direction indicated by arrow C2 due to the biasing force of the coil spring 62. As a result, the fixing belt 11 comes into contact with the pressure roller 20, and a fixing nip is formed. At the start of the fixing operation, a fixing nip is formed between the fixing belt 11 and the pressure roller 20 in this manner.

[0056] Furthermore, a terminal section 59 connected to the heater 15 (Figure 2) and temperature sensor 17 is attached to one of the side frames 51. Wiring W is drawn out from the terminal section 59 and connected to a heater control circuit (not shown). During the fixing operation, the power supply to the heater 15 is controlled based on the temperature detected by the temperature sensor 17.

[0057] <Flange member 30> Figures 8(A), (B), and (C) are perspective, front, and side views of the flange member 30. Although only one flange member 30 is shown in Figures 8(A) to (C), the other flange member 30 has a shape symmetrical to the flange member 30 shown in Figures 8(A) to (C) with respect to the center in the X direction.

[0058] The flange member 30 is formed of a resin such as PPS (polyphenylene sulfide). As shown in Figures 8(A) to (C), the flange member 30 has a substantially semi-cylindrical core portion 31 that supports the anchoring belt 11 from the inner circumference, and an annular portion 32 adjacent to the core portion 31 in the X direction.

[0059] The core portion 31 has an arc-shaped contact surface 31a centered on a central axis extending in the X direction. The contact surface 31a of the core portion 31 is the surface on which the inner circumferential surface of the fixing belt 11 slides.

[0060] A rectangular cavity 31b is formed inside the core portion 31, which fits into the stay 12 (Figure 6). The X-direction end of the stay 12 passes through the cavity 31b of the core portion 31 and is fixed to the swing lever 55.

[0061] An opening 31c is formed below the core portion 31 (in the -Z direction). Through this opening 31c, the heater support member 13 (Figure 2), which is attached to the stay 12, faces the anchoring belt 11.

[0062] The core portion 31 has a tapered surface 31d on the side opposite to the annular portion 32 in the X direction. This tapered surface 31d is provided to facilitate the attachment of the anchoring belt 11 to the core portion 31.

[0063] The annular portion 32 is formed to protrude radially outward from the core portion 31. The surface of the annular portion 32 on the core portion 31 side (the surface in the -X direction) is abutment surface 32a that abuts against the sliding ring 40. The abutment surface 32a is a surface parallel to the XZ plane. A tapered surface 32b is formed at the lower end of the annular portion 32 (the end in the -Z direction) and is inclined with respect to the XZ plane.

[0064] Furthermore, a fixing hole 32c is formed near the upper end (the end in the +Z direction) of the annular portion 32, through which a screw for fixing the flange member 30 to the swing lever 55 passes.

[0065] As shown in Figure 8(C), a support groove 33 is formed at the end of the core portion 31 on the annular portion 32 side, which rotatably supports the sliding ring 40. The bottom surface (contact surface) 33a of the support groove 33 extends in an arc shape with respect to a central axis that extends in the X direction.

[0066] <Sliding ring 40> Figure 9(A) is a perspective view showing the shape of the sliding ring 40. The sliding ring 40 has an outer circumference 41 and an inner circumference 42. A gear portion G is formed on the outer circumference 41. The sliding ring 40 also has a first contact surface 43 facing the end of the anchoring belt 11 and a second contact surface 44 facing the abutment surface 32a of the flange member 30.

[0067] The sliding ring 40 is made of a resin such as PEEK (polyether ether ketone) or PPS. The inner diameter of the sliding ring 40 is, for example, 29.2 mm, and the outer diameter is, for example, 35 mm. The width H of the sliding ring 40 is, for example, 2.9 mm and is constant in the circumferential direction. The thickness T of the sliding ring 40 is, for example, 0.3 mm. That is, the sliding ring 40 has a thickness that allows it to flex in the thickness direction.

[0068] Figure 9(B) is a schematic diagram showing the state in which the sliding ring 40 is attached to the support groove 33 of the flange member 30. As shown in Figure 9(B), the width of the support groove 33 is wider than the thickness of the sliding ring 40, and the sliding ring 40 can move by a predetermined amount in the X direction within the support groove 33.

[0069] When the anchoring belt 11 is attached to the core portion 31 of the flange member 30, the end of the anchoring belt 11 in the width direction (X direction) faces the first contact surface 43 of the sliding ring 40. As the anchoring belt 11 rotates, and moves towards the X direction as indicated by the arrow, the end of the anchoring belt 11 in the X direction comes into contact with the first contact surface 43 of the sliding ring 40. As a result, the sliding ring 40 moves toward the abutment surface 32a, and the second contact surface 44 comes into contact with the abutment surface 32a. This restricts the position of the anchoring belt 11 in the X direction.

[0070] Furthermore, in the portion where the opening 31c of the core portion 31 (Figure 8(A), (B)) is formed, the anchoring belt 11 does not come into contact with the contact surface 31a. Therefore, when the anchoring belt 11 passes through this portion and comes into contact with the contact surface 31a again, it may be displaced in the X direction. In that case, the sliding ring 40 will bend, and this bending of the sliding ring 40 can be accommodated by the tapered surface 32b.

[0071] Furthermore, the oscillating lever 55 is provided with a retaining ring 58 (see Figures 5 and 6) to prevent the sliding ring 40 from lifting upward (in the +Z direction) from the support groove 33 of the flange member 30.

[0072] <Drive force transmission unit 7> Figure 10 is a cross-sectional view along line segment 10-10 in Figure 7. Figure 11 is a cross-sectional view along line segment 11-11 in Figure 7. As shown in Figure 10, each oscillating lever 55 of the fixing device 10 is provided with a drive force transmission unit 7 that transmits the rotation of the fixing belt 11 to the sliding ring 40. The drive force transmission unit 7 is provided above (+Z direction) the fixing belt 11 in this case, but it does not necessarily have to be above.

[0073] The drive force transmission unit 7 includes a contact roller 71 that contacts the outer circumferential surface of the anchoring belt 11, a transmission gear 72 (Figure 11) coaxial with the contact roller 71, an idler gear 73 that meshes with the transmission gear 72, and a reduction gear 74 that meshes with the idler gear 73.

[0074] The contact roller 71 is fixed to a rotating shaft 70 (Figures 5, 6) that extends in the X direction between a pair of oscillating levers 55. The rotating shaft 70 is rotatably mounted in holes provided in each oscillating lever 55. The contact roller 71 contacts the vicinity of the X-direction end of the outer circumferential surface of the fixing belt 11 and rotates in accordance with the fixing belt 11 due to friction between it and the fixing belt 11.

[0075] As shown in Figure 11, the transmission gear 72 is attached to the rotating shaft 70 and rotates together with the rotating shaft 70 and the contact roller 71.

[0076] The idler gear 73 is rotatably supported on a pivot shaft 55b in the X direction provided on the oscillating lever 55 and meshes with the transmission gear 72.

[0077] The reduction gear 74 is rotatably supported on a pivot shaft 55c in the X direction provided on the oscillating lever 55. The reduction gear 74 has a first gear section 74a and a second gear section 74b in the X direction. The second gear section 74b has a larger outer diameter and more teeth than the first gear section 74a.

[0078] The first gear portion 74a of the reduction gear 74 meshes with the idler gear 73. The second gear portion 74b of the reduction gear 74 meshes with the gear portion G on the outer circumference 41 of the sliding ring 40, as shown in Figure 10. Note that in Figures 10, 11 and the following Figure 12, gears 72, 73 and gear portions 74a, 74b, and G are all shown as circles (pitch circles).

[0079] Figure 12 is a schematic diagram illustrating the rotational directions of the fixing belt 11, contact roller 71, transmission gear 72, idler gear 73, reduction gear 74, and sliding ring 40.

[0080] In Figure 12, the rotation direction of the anchoring belt 11, indicated by arrow R1, is defined as the first rotation direction (for example, clockwise). When the anchoring belt 11 rotates in the first rotation direction, the contact roller 71 in contact with the anchoring belt 11 rotates in a second rotation direction (for example, counterclockwise), opposite to the rotation direction of the anchoring belt 11, as indicated by arrow R2.

[0081] When the contact roller 71 rotates in the second rotational direction, the transmission gear 72, which is mounted on the same rotational shaft 70 as the contact roller 71, also rotates in the same second rotational direction as the contact roller 71, as indicated by arrow R2.

[0082] When the transmission gear 72 rotates in the second rotational direction, the idler gear 73, which is meshed with the transmission gear 72, rotates in the first rotational direction opposite to the rotational direction of the transmission gear 72, as indicated by arrow R3.

[0083] When the idler gear 73 rotates in the first rotational direction, the reduction gear 74, which is meshed with the idler gear 73 at the first gear section 74a, rotates in a second rotational direction opposite to the rotational direction of the idler gear 73, as indicated by arrow R4.

[0084] When the reduction gear 74 rotates in the second rotational direction, the sliding ring 40, whose gear portion G meshes with the second gear portion 74b of the reduction gear 74, rotates in the first rotational direction opposite to the rotational direction of the reduction gear 74, as indicated by arrow R5.

[0085] In this way, the rotation of the anchoring belt 11 is transmitted to the sliding ring 40 via the contact roller 71, transmission gear 72, idler gear 73, and reduction gear 74, and the sliding ring 40 rotates in the same direction as the anchoring belt 11 (first rotation direction).

[0086] The rotational speed of the sliding ring 40 is determined by the outer diameter of the fixing belt 11, the outer diameter of the contact roller 71, the number of teeth of the transmission gear 72, the number of teeth of the idler gear 73, the number of teeth of the first gear section 74a and the second gear section 74b of the reduction gear 74, and the number of teeth of the sliding ring 40.

[0087] In Embodiment 1, the outer diameter and number of teeth of the components of the drive force transmission unit 7 are determined such that the rotational speed (rotational speed N1) of the sliding ring 40 is approximately the same as the rotational speed (rotational speed N2) of the fixing belt 11. Note that rotational speeds N1 and N2 refer to the number of rotations per unit time.

[0088] Here, one rotation of the fixing belt 11 means that a point on the fixing belt 11 returns to its original position due to rotation. Similarly, one rotation of the sliding ring 40 means that a point on the sliding ring 40 returns to its original position due to rotation. The rotational speeds N1 and N2 of the fixing belt 11 and sliding ring 40 represent the number of rotations per unit time when the fixing belt 11 and sliding ring 40 are rotating, such as during fixing operation or warm-up.

[0089] <Operation of the image forming apparatus> Next, the operation of the image forming apparatus 1 will be explained with reference to Figure 1. When the control unit of the image forming apparatus 1 receives a print command and print data from the host device, it starts the image forming operation (printing operation).

[0090] First, the pickup roller 112 and feed roller 113 rotate, feeding the media P stored in the paper tray 111 one sheet at a time onto the transport path. Then, the transport roller pair 115 and 116 rotate, transporting the media P along the transport path to the transfer unit 90.

[0091] In the transfer unit 90, a transfer belt 92, which moves by the rotation of a drive roller 93, adsorbs, holds, and transports the medium P. The medium P passes through the process units 80K, 80Y, 80M, and 80C in that order.

[0092] In each process unit 80, a charging voltage, a developing voltage, and a supply voltage are applied to the charging roller 82, the developing roller 84, and the supply roller 85, respectively. The photoreceptor drum 81 also rotates, causing the charging roller 82, the developing roller 84, and the supply roller 85 to rotate as well.

[0093] The charging roller 82 uniformly charges the surface of the photoreceptor drum 81. The print head 83 exposes the uniformly charged surface of the photoreceptor drum 81 to form an electrostatic latent image. The electrostatic latent image formed on the surface of the photoreceptor drum 81 is developed by the toner adhering to the developing roller 84 to form a toner image.

[0094] The toner image formed on the photoreceptor drum 81 is transferred to the medium P on the transfer belt 92 by the transfer voltage applied to the transfer roller 91. Toner that is not transferred to the medium P is scraped off by the cleaning member 86.

[0095] In this way, the toner images of each color formed in each process unit 80K, 80Y, 80M, and 80C are transferred to the medium P. The medium P on which the toner images of each color have been transferred is further transported by the transfer belt 92 and reaches the fixing device 10.

[0096] In the fixing device 10, a fixing nip is formed between the fixing belt 11 and the pressure roller 20. Furthermore, as the pressure roller 20 rotates due to the fixing motor, the fixing belt 11, which is in contact with the pressure roller 20 at the fixing nip, rotates in accordance with the pressure roller 20. During the warm-up before the start of the fixing operation, heat from the heater 15 is transferred to the fixing belt 11 via the heat diffusion member 16, heating the fixing belt 11 so that it reaches a predetermined fixing temperature at the start of the fixing operation.

[0097] The medium P onto which the toner image has been transferred enters the fixing nip between the fixing belt 11 and the pressure roller 20, where heat and pressure are applied, causing the toner to melt and fix to the medium P.

[0098] The medium P on which the toner image has been fixed is discharged to the outside of the image forming apparatus 1 by the discharge roller pairs 121, 122, and 123 and stacked on the stacker section 124. This completes the formation of the color image on the medium P.

[0099] <effect> In the fixing operation described above, as the fixing belt 11 rotates, the fixing belt 11 moves in the +X direction or the -X direction. At that time, as explained with reference to Figure 9(B), the end of the fixing belt 11 comes into contact with the sliding ring 40, and the sliding ring 40 comes into contact with the abutment surface 32a, thereby restricting the position of the fixing belt 11 in the width direction.

[0100] In conventional fixing devices, the sliding ring 40 rotates in accordance with the fixing belt 11 due to friction with the end of the fixing belt 11. Therefore, depending on the contact condition between the end of the fixing belt 11 and the sliding ring 40, the rotation of the sliding ring 40 may become unstable, potentially leading to damage (including wear) to the fixing belt 11 or the sliding ring 40.

[0101] In particular, if the grease applied between the fixing belt 11 and the heat diffusion member 16 (Figure 2) leaks from the widthwise end of the fixing belt 11 and adheres to the sliding ring 40, the friction between the end of the fixing belt 11 and the sliding ring 40 decreases, making it easier for the rotation of the sliding ring 40 to become unstable.

[0102] In contrast, in Embodiment 1, as shown in Figure 12, the rotation of the fixing belt 11 is transmitted to the sliding ring 40 via the contact roller 71, transmission gear 72, idler gear 73, and reduction gear 74 (first gear section 74a and second gear section 74b), and the sliding ring 40 rotates in the same direction as the fixing belt 11 at approximately the same rotational speed (number of rotations).

[0103] Therefore, regardless of the contact state between the end of the fixing belt 11 and the sliding ring 40, the rotation of the sliding ring 40 can be stabilized, and damage to the fixing belt 11 and the sliding ring 40 can be suppressed.

[0104] In other words, even if the friction between the end of the fixing belt 11 and the sliding ring 40 decreases due to the adhesion of grease, damage to the fixing belt 11 and the sliding ring 40 can be suppressed by controlling the rotational speed of the sliding ring 40 relative to the rotational speed of the fixing belt 11 with the drive force transmission unit 7.

[0105] Ideally, the rotational speed N1 of the sliding ring 40 should be the same as the rotational speed N2 of the fixing belt 11 (N1=N2). However, considering the manufacturing tolerance (±1%), it is acceptable if the rotational speed N1 falls within ±1% of the rotational speed N2.

[0106] Here, an example has been described in which the drive force transmission unit 7 transmits the rotation of the fixing belt 11 to the sliding ring 40. However, the rotation (driving force) of a drive source other than the fixing belt 11 may also be transmitted to the sliding ring 40. For example, the rotation of the pressure roller 20 may be transmitted to the sliding ring 40. Alternatively, the rotation (driving force) of a unique drive source may be transmitted to the sliding ring 40.

[0107] <Effects of Embodiment 1> As described above, the fixing device 10 of Embodiment 1 includes a fixing belt 11 as a rotatable annular belt, a sliding ring 40 as a contact member that can contact the end of the fixing belt 11, and a driving force transmission unit 7 that transmits driving force to the sliding ring 40 and controls the rotational speed of the sliding ring 40 relative to the rotational speed of the fixing belt 11. Therefore, the rotation of the sliding ring 40 can be stabilized, and damage to the fixing belt 11 and the sliding ring 40 caused by sliding between the fixing belt 11 and the sliding ring 40 can be suppressed.

[0108] Furthermore, since the rotational speed N1 of the sliding ring 40 is approximately the same as the rotational speed N2 of the anchoring belt 11, the sliding between the end of the anchoring belt 11 and the sliding ring 40 is minimized, thereby enhancing the effect of suppressing damage to both the anchoring belt 11 and the sliding ring 40.

[0109] Furthermore, since the drive force transmission section 7 has gears 72 to 74, the drive force can be transmitted to the sliding ring 40 with a simple configuration. Also, since the sliding ring 40 is annular and has a gear section G on its outer circumference, the drive force transmitted via gears 72 to 74 can be reliably transmitted to the sliding ring 40.

[0110] Furthermore, it can be said that the drive force transmission unit 7 transmits the driving force of the pressure roller 20, which is the driving source for the fixing belt 11, to the sliding ring 40. Since the fixing belt 11 and the sliding ring 40 rotate with the driving force of a common drive source, it is possible to suppress the change in the rotational speed of the sliding ring 40 relative to the rotational speed of the fixing belt 11.

[0111] Furthermore, since the drive force transmission unit 7 transmits the rotation of the fixing belt 11 to the sliding ring 40, even if a difference in rotational speed occurs between the fixing belt 11 and the pressure roller 20 due to a difference in thermal expansion, the rotational speed of the sliding ring 40 can be accurately matched to the rotational speed of the fixing belt 11.

[0112] Furthermore, the drive force transmission unit 7 has a contact roller 71 that contacts the fixing belt 11 and rotates together with the fixing belt 11, and transmits the rotation of the contact roller 71 to the sliding ring 40 via a plurality of gears 72 to 74. As a result, with a simple configuration, the rotational speed of the sliding ring 40 can be accurately matched to the rotational speed of the fixing belt 11.

[0113] Furthermore, the system includes a flange member 30 as a belt holding portion for holding the end of the fixing belt 11, and the sliding ring 40 is slidably attached to the flange member 30, so that the sliding ring 40 can be held in contact with the end of the fixing belt 11.

[0114] In addition, since the fixing belt 11 is provided with a heater 15 for heating, the heat necessary for fixing the toner image to the medium P can be supplied to the fixing nip.

[0115] Embodiment 2. FIG. 13 is a cross-sectional view showing a main part of the fixing device according to Embodiment 2, and corresponds to the cross-sectional view taken along the line segment 10-10 shown in FIG. 7. The driving force transmission unit 7A of the fixing device according to Embodiment 2 has a different reduction ratio from the driving force transmission unit 7 of the fixing device according to Embodiment 1.

[0116] The driving force transmission unit 7 of the fixing device according to Embodiment 2 includes the contact roller 71, the transmission gear 72, the idle gear 73, and the reduction gear 74 (the first gear part 74a and the second gear part 74b) described in Embodiment 1.

[0117] In Embodiment 1, the rotation speed N1 of the sliding ring 40 was substantially the same as the rotation speed N2 of the fixing belt 11. In contrast, in Embodiment 2, the rotation speed N1 of the sliding ring 40 is greater than the rotation speed N2 of the fixing belt 11 (that is, N1 > N2).

[0118] Such a reduction ratio can be realized by changing, for example, the ratio of the number of teeth of the first gear part 74a and the number of teeth of the second gear part 74b of the reduction gear 74 with respect to the driving force transmission unit 7 of Embodiment 1. Not limited to the reduction gear 74, the number of teeth of other gears may be changed.

[0119] The fixing belt 11 is indicated by reference numeral A in FIG. 13 when the rotation speed N1 of the sliding ring 40 is greater than the rotation speed N2 of the fixing belt 11 (that is, N1 > N2). The fixing belt 11 when the rotation speed N1 of the sliding ring 40 is less than the rotation speed N2 of the fixing belt 11 (that is, N1 < N2) is indicated by reference numeral B.

[0120] FIG. 14 is a diagram showing an enlarged view of the region on the downstream side of the fixing nip (the portion surrounded by the broken line C in FIG. 13). As described above, the fixing belt 11 rotates by coming into contact with the pressure roller 20 at the fixing nip.

[0121] Therefore, as shown in Figure 14, the anchoring belt 11 rotates while maintaining contact with the flange member 30 on the upstream side of the anchoring nip (right side in Figure 14), and rotates with a gap between it and the flange member 30 (i.e., bulging outwards) on the downstream side of the anchoring nip (left side in Figure 14). Consequently, deformation of the anchoring belt 11 due to sliding with the sliding ring 40 is more likely to occur on the downstream side of the anchoring nip, where the degree of freedom of deformation is greater.

[0122] When the rotational speed N1 of the sliding ring 40 is greater than the rotational speed N2 of the anchoring belt 11, the anchoring belt 11 is pulled by the sliding ring 40, and therefore the anchoring belt 11 is subjected to a force in the direction of its rotation (indicated by arrow R1).

[0123] Therefore, when the rotational speed N1 of the sliding ring 40 is greater than the rotational speed N2 of the fixing belt 11 (indicated by symbol A), the bulging portion of the fixing belt 11 toward the outer circumference is located higher compared to when the rotational speed N1 of the sliding ring 40 is less than the rotational speed N2 of the fixing belt 11 (indicated by symbol B).

[0124] In other words, when the rotational speed N1 of the sliding ring 40 is greater than the rotational speed N2 of the fixing belt 11, the downward bulge of the fixing belt 11 downstream of the fixing nip (shown by the dashed line D in Figure 14) is smaller.

[0125] Therefore, by making the rotational speed N1 of the sliding ring 40 greater than the rotational speed N2 of the fixing belt 11, the downward bulging of the fixing belt 11 near the downstream side of the fixing nip can be suppressed.

[0126] During the fixing operation, it is desirable that the medium P that has passed through the fixing nip does not adhere to the fixing belt 11 and separates smoothly from the fixing belt 11. To improve the separation of the medium P from the fixing belt 11, it is desirable that the curvature of the fixing belt 11 is greater downstream of the fixing nip.

[0127] As described above, by making the rotational speed N1 of the sliding ring 40 greater than the rotational speed N2 of the fixing belt 11, and suppressing the downward bulge of the fixing belt 11 downstream of the fixing nip, the curvature of the fixing belt 11 downstream of the fixing nip can be increased, thereby improving the separation of the medium P from the fixing belt 11.

[0128] Furthermore, depending on how the anchoring belt 11 bulges downward, it is possible that the anchoring belt 11 may bend inward (reverse bend) downstream of the anchoring nip. If such reverse bend occurs, the load on the anchoring belt 11 due to deformation will increase, which may cause the anchoring belt 11 to break.

[0129] As described above, by making the rotational speed N1 of the sliding ring 40 greater than the rotational speed N2 of the fixing belt 11, the downward bulging of the fixing belt 11 downstream of the fixing nip can be suppressed, thereby suppressing reverse bending of the fixing belt 11 and preventing damage to the fixing belt 11.

[0130] The ratio of the rotational speed N1 of the sliding ring 40 to the rotational speed N2 of the fixing belt 11 (N1 / N2) is determined by the outer diameters of the contact roller 71 and the fixing belt 11, as well as the number of teeth of the gears 72-74, and is therefore affected by manufacturing tolerances (especially dimensional tolerances of the outer diameters of the contact roller 71 and the fixing belt 11). If the rotational speed N1 of the sliding ring 40 is made larger than the rotational speed N2 of the fixing belt 11 by the amount of the manufacturing tolerance (for example, ±1%), the relative magnitudes of the rotational speeds N1 and N2 will not be reversed even when affected by manufacturing tolerances.

[0131] If the difference between the rotational speed N1 of the sliding ring 40 and the rotational speed N2 of the fixing belt 11 is too large, the frictional force (sliding resistance) acting between them may cause damage to either the sliding ring 40 or the fixing belt 11.

[0132] In order to suppress damage to the sliding ring 40 and the fixing belt 11, it is desirable that the rotational speed N1 of the sliding ring 40 be 1.2 times or less, more preferably 1.1 times or less, the rotational speed N2 of the fixing belt 11. In other words, it is desirable to satisfy N2 < N1 ≦ 1.2×N2, and more preferably to satisfy N2 < N1 ≦ 1.1×N2.

[0133] <Effect of Embodiment 2> As described above, in Embodiment 2, by making the rotational speed N1 of the sliding ring 40 greater than the rotational speed N2 of the fixing belt 11, the separability of the medium P from the fixing belt 11 can be improved.

[0134] In particular, by satisfying N2 < N1 ≦ 1.2×N2 (more preferably N2 < N1 ≦ 1.1×N2) for the rotational speed N1 of the sliding ring 40 and the rotational speed N2 of the fixing belt 11, while improving the separability of the medium P from the fixing belt 11, the effect of suppressing damage to the sliding ring 40 and the fixing belt 11 can be enhanced.

[0135] <Other Configuration Examples> Although the embodiments and modification examples have been described above, the present disclosure is not limited to the above-described embodiments and modification examples, and various modifications or alterations are possible.

[0136] In the above-described Embodiments 1 and 2, as shown in FIG. 7 and the like, the driving force transmission portion 7 was provided on the two swing levers 55 of the fixing device 10. However, the driving force transmission portion 7 may be provided only on one of the two swing levers 55, as in the configuration example shown in FIG. 15.

[0137] Furthermore, in embodiments 1 and 2 described above, the stay 12, heater support member 13, heat conduction member 14, heater 15, heat diffusion member 16, and temperature sensor 17 were provided on the inner circumference side of the fixing belt 11 (see Figure 2). However, the configuration is not limited to this, and any configuration that allows the fixing belt 11 to be heated from the inner circumference side by the heater 15 is acceptable. Also, although the heater 15 was positioned opposite the fixing nip (see Figure 2), the heater 15 may be positioned at any other location as long as the fixing belt 11 can be heated.

[0138] This disclosure can be used in image forming apparatuses (e.g., photocopiers, facsimile machines, printers, multifunction devices, etc.) and their fixing devices, which use an electrophotographic method to form images on a medium.

[0139] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A rotatable annular belt, A contact member that can abut against the end of the annular belt, A drive force transmission unit that transmits driving force to the contact member and controls the rotational speed of the contact member in relation to the rotational speed of the annular belt, A fixing device characterized by being equipped with the following features. (Note 2) The rotational speed N1 of the contact member per unit time is equal to or greater than the rotational speed N2 of the annular belt per unit time. The fixing device according to Appendix 1, characterized in that it is a fixing device. (Note 3) The rotational speed N1 of the contact member per unit time and the rotational speed N2 of the annular belt per unit time satisfy N1 ≤ 1.2 × N2. A fixing device as described in Appendix 1 or 2, characterized by the above. (Note 4) The aforementioned drive force transmission unit has a plurality of gears A fixing device as described in any one of the appendices 1 to 3, characterized by the above. (Note 5) The aforementioned contact member is annular in shape and has a gear portion on its outer circumference. A fixing device as described in any one of the appendices 1 to 4, characterized by the above. (Note 6) The aforementioned annular belt rotates due to the driving force of the drive source, The driving force transmission unit transmits the driving force of the driving source to the contact member. A fixing device as described in any one of the appendices 1 to 5, characterized by the above. (Note 7) The drive force transmission unit transmits the rotation of the annular belt, which rotates due to the driving force of the drive source, to the contact member. The fixing device described in Appendix 6, characterized by the features described herein. (Note 8) The aforementioned drive force transmission unit is It has a contact roller that abuts against the annular belt and rotates together with the annular belt, The rotation of the contact roller is transmitted to the contact member via a plurality of gears. The fixing device described in Appendix 7, characterized by the features described herein. (Note 9) The device further includes a pressure roller positioned on the outer circumference of the annular belt, which forms a fixing nip between itself and the annular belt. The drive source is the pressure roller. A fixing device as described in any one of the appendices 6 to 8, characterized by the above. (Note 10) An image forming unit that forms an image on a medium, A fixing device according to any one of the appendices 1 to 9, which fixes the image formed by the image forming unit onto the medium. An image forming apparatus equipped with [a specific feature]. [Explanation of symbols]

[0140] 1 Image forming apparatus, 7,7A Drive force transmission unit, 10 Fixing device, 11 Fixing belt (annular belt), 15 Heater, 16 Heat diffusion member, 17 Temperature sensor, 18 Oscillating unit, 20 Pressure roller, 21 Shaft, 30 Flange member (belt holding member), 31 Core part, 32 Flange part, 33 Support groove, 40 Sliding ring, 55 Oscillating lever, 57 Contact plate, 60 Cam, 70 Rotating shaft, 71 Contact roller (contact member), 72 Transmission gear, 73 Idler gear, 74 Reduction gear, 74a First gear part, 74b Second gear part, 80,80K,80Y,80M,80C Process unit, 81 Photoreceptor drum (image carrier), 82 Charging roller (charging component), 83 Print head (exposure device), 84 Developer roller (developer carrier), 85 Supply roller (supply component), 87 Toner cartridge (developer container), 90 Transfer unit, 110 Media supply unit, 120 Media discharge unit, G Gear unit.

Claims

1. A rotatable annular belt, A contact member that can abut against the end of the annular belt, A drive force transmission unit that transmits driving force to the contact member and controls the rotational speed of the contact member in relation to the rotational speed of the annular belt, A fixing device characterized by being equipped with the following features.

2. The rotational speed N1 of the contact member per unit time is equal to or greater than the rotational speed N2 of the annular belt per unit time. The fixing device according to feature 1.

3. The rotational speed N1 of the contact member per unit time and the rotational speed N2 of the annular belt per unit time satisfy N1 ≤ 1.2 × N2. The fixing device according to feature 2.

4. The aforementioned drive force transmission unit has a plurality of gears The fixing device according to feature 1.

5. The aforementioned contact member is annular in shape and has a gear portion on its outer circumference. The fixing device according to feature 4.

6. The aforementioned annular belt rotates due to the driving force of the drive source, The driving force transmission unit transmits the driving force of the driving source to the contact member. The fixing device according to feature 1.

7. The drive force transmission unit transmits the rotation of the annular belt, which rotates due to the driving force of the drive source, to the contact member. The fixing device according to feature 6.

8. The aforementioned drive force transmission unit is It has a contact roller that abuts against the annular belt and rotates together with the annular belt, The rotation of the contact roller is transmitted to the contact member via a plurality of gears. The fixing device according to feature 7.

9. The device further includes a pressure roller positioned on the outer circumference of the annular belt, which forms a fixing nip between itself and the annular belt. The drive source is the pressure roller. The fixing device according to feature 6.

10. An image forming unit that forms an image on a medium, A fixing device according to any one of claims 1 to 9, which fixes an image formed by the image forming unit onto the medium. An image forming apparatus equipped with [a specific feature].

Images