Image Heating Device

Abstract

To compatibly achieve wear suppression of an end face of a gear and operational stability of a drive transmission member 102 in a one-way clutch unit 100.SOLUTION: A concave shape part 101f is provided between a fitting hole 101b with a rotational shaft 104 of an input gear 101 and a contact surface 101c with the drive transmission member 102 so as to prevent viscous grease G applied for wear suppression of a gear end face 101a from adhering to the drive transmission member 102.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image heating apparatus using a one-way clutch unit that transmits or blocks a driving force input from a driving source to a driven body depending on the direction of rotation. [Background technology]

[0002] The fixing device used in the image forming apparatus has a heating rotator that heats an unfixed toner image carried on a recording material, a heater that heats the heating rotator, and a pressure rotator that forms a nip portion together with the heating rotator. The toner image is fixed to the recording material by heating the recording material carrying the unfixed toner image while conveying it through the nip portion.

[0003] This fixing device is provided with a pressure release mechanism that releases pressure in the nip area to improve jam handling when a jam occurs during transport of the recording material and to prevent compressive distortion (plastic deformation) of the heating rotor and pressure rotor in the nip formation area.

[0004] This pressure release mechanism may use a manual pressure release mechanism using a lever or an automatic pressure release mechanism using a motor, but in recent years, from the standpoint of user operability and cost reduction, there has been a demand for driving and rotating multiple rotating bodies with fewer motors.

[0005] From the above viewpoint, in a configuration in which a single motor rotates a plurality of rotating bodies to perform pressure release, it is desirable to selectively rotate the pressurizing rotating body and the pressure release cam.

[0006] In response to the above, Patent Document 1 proposes a configuration in which a one-way clutch unit (one-way clutch) is placed in the drive transmission path from the motor to the rotor, and the motor rotates forward and backward to selectively drive the rotor. A typical one-way clutch unit has multiple balls and needles arranged in the circumferential direction, so it has a large number of parts and a complex structure, making small one-way clutch units expensive.

[0007] As a solution to this problem, Patent Document 2 proposes a simple one-way clutch unit having a small number of parts, as shown in FIG.

[0008] As shown in FIG. 2, the one-way clutch unit 100 is composed of an input gear 101, a drive transmission member 102, and an output gear 103. As shown in FIG. 3, the direction in which the drive transmission member 102 is biased varies depending on the rotation direction of the input gear 101. For example, when the input gear 101 rotates in the direction of arrow C in FIG. 3a, the drive transmission member 102 is biased toward the output gear 103 (in the direction of arrow H) and engages with the output gear 103 to transmit the drive. When the input gear 101 rotates in the direction of arrow D in FIG. 3b, the drive transmission member 102 is biased toward the side away from the output gear 103 (in the direction of arrow I), and the drive is released. The drive transmission member 102 has a biasing portion 102a that abuts against an inner peripheral surface 103a of the output gear 103, and the biasing force generated by the biasing portion 102a enables the biasing direction of the drive transmission member 102 to be switched by switching the rotation direction of the input gear 101. Further, the input gear 101 has an engagement portion 101b for switching the drive transmission member 102, which extends in the radial direction from the center of the input gear.

[0009] In such a one-way clutch unit 101, the input gear 101 and the output gear 103 may be configured with helical gears to reduce driving noise. Generally, when a helical gear rotates, a force is generated in the gear in the thrust direction. When the input gear 101 is configured with a helical gear, the direction of the force generated in the gear is reversed when the gear rotates in the direction to transmit the driving force and when the gear rotates in the direction to release the driving force.

[0010] For example, if the twist direction of the input gear 101 is to the right, the direction of the force generated by rotation is the direction of arrow E when rotating in the direction in which the drive is transmitted (the direction of arrow C) in Figure 3a, and the direction of arrow F when rotating in the direction in which the drive is released (the direction of arrow D) in Figure 3b.

[0011] There is a problem that the end face 101a of the input gear 101 is worn due to friction with an opposing member when the input gear 101 rotates with a force applied in the direction of the arrow E. As a countermeasure, a method is known in which viscous grease is applied to the end face 101a of the input gear 101 to suppress wear of the gear end face. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 6-118784 [Patent Document 2] JP 2019-100479 A Summary of the Invention [Problem to be solved by the invention]

[0013] However, if viscous grease is applied to the gear end face 101a to suppress wear of the end face 101a of the input gear 101, the grease applied to the gear end face 101a will pass through the gap between the rotating shaft 104 of the input gear 101 and the hole 101b of the input gear 101, and the viscous grease G will enter the inside of the one-way clutch unit 100, as shown in Figure 4.

[0014] When the viscous grease G penetrates into the one-way clutch unit 100, the viscous grease G adheres to the surface 101c of the input gear 101 with which the drive transmission member 102 abuts. When the viscous grease G adheres to the abutment surface 101c of the drive transmission member 102 of the input gear 101, the input gear 101 rotates in the drive release direction (FIG. 3b), and the drive transmission member 102 moves toward the input gear 101 (in the direction of the arrow I). When the viscous grease G is present between the surface 101c and the drive cam 102, the drive transmission member 102 is attracted to the input gear 101 by the viscous grease G. This causes a problem that even if the input gear 101 rotates in the drive transmission direction (FIG. 3a), the drive transmission member 102 cannot move in the direction in which it couples with the output gear 103 (in the direction of the arrow H), and the drive remains released. [Means for solving the problem]

[0015] The present invention relates to a printing apparatus including a first rotating body and a second rotating body which form a nip portion for sandwiching and conveying a recording material in order to heat a toner image formed on the recording material, a drive source, a one-way clutch unit which transmits a drive force for rotating the first rotating body when the drive source rotates forward and does not transmit a drive force for rotating the first rotating body when the drive source rotates reversely, and a switching mechanism which changes a pressure force between the first rotating body and the second rotating body or separates the first rotating body and the second rotating body from each other when the drive source rotates reversely, and the one-way clutch unit includes a shaft, an input gear supported by the shaft and into which the drive force of the drive source is input, and a switching mechanism which is supported by the shaft and has a drive force of the drive source and a switching mechanism which is connected to the shaft ... an image heating apparatus having an output gear supported by the shaft and outputting a driving force, and a drive transmission member supported by the shaft and shifting in the axial direction of the shaft to switch between transmission and non-transmission of driving force from the input gear to the output gear, the output gear having a cylindrical housing portion for housing the drive transmission member therein so as to be movable in the axial direction, and an annular second tooth surface having a plurality of protrusions and recesses which meshes with an annular first tooth surface formed of a plurality of protrusions and recesses provided on the drive transmission member when the drive source rotates forward, and which does not mesh with the first tooth surface and moves the drive transmission member away when the drive source rotates reversely, the input gear having an abutment surface against which the drive transmission member abuts, an end surface that abuts against the shaft; The above Axis? a restricting portion extending from the input gear toward an outer periphery of the input gear and engaging with the drive transmission member to restrict rotation of the drive transmission member, The end surface is coated with grease, the drive transmission member has a cam portion that engages with the restricting portion to convert a rotational force of the input gear into a force that moves the drive transmission member in the axial direction, The input gear is a ring-shaped recessed portion provided between the shaft and the abutment surface and recessed in the axial direction from the abutment surface; The recess is provided between the shaft and the abutting surface and faces the shaft. The present invention is characterized by the above. Effect of the Invention

[0016] According to the present invention, when grease is transmitted to the bearing portion of the input gear through the shaft, adhesion between the input gear and the drive transmission portion due to the presence of the grease can be suppressed. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a one-way clutch 100 according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view of a one-way clutch 100 according to a conventional example. [Diagram 3] 1 is a cross-sectional view showing a drive in a connected / disconnected state according to a conventional example and this embodiment; [Figure 4] FIG. 1 is a cross-sectional view showing an intrusion path of viscous grease G according to a conventional example. [Diagram 5] 1 is a perspective view of a drive transmission member 102 according to a conventional example and the present embodiment; [Figure 6] 1 is a cross-sectional view showing the effect of a concave shape 101f of the input gear 101 according to the present embodiment. [Figure 7] 1 is a cross-sectional view of an image forming apparatus 500 according to an embodiment of the present invention. [Figure 8] 1 is a cross-sectional view of a fixing device 20 according to the present embodiment. [Figure 9] 1 is a cross-sectional view of a pressure release mechanism 208 of a fixing device 20 according to the present embodiment. [Figure 10] FIG. 2 is a side view of the fixing device 20 on the side of the drive switching device 300 according to the present embodiment. [Figure 11] FIG. 1 is a perspective view of a drive switching device 300 according to an embodiment of the present invention; [Figure 12] 1 is a diagram showing the configuration of a pendulum gear 312 according to the present embodiment; [Figure 13] 1 is a diagram showing the operation of the pendulum gear 312 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The best mode for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the present invention is not limited to the following embodiments. EXAMPLES

[0019] (Image forming apparatus 500) FIG. 7 is a cross-sectional view of an image forming apparatus 500 according to the present embodiment.

[0020] Each of the four cartridges 1Y, 1M, 1C, and 1Bk arranged diagonally vertically includes a photosensitive drum 2 as an electrophotographic photosensitive member, a charging roller 3, a cleaning member 6, and a developing unit 4.

[0021] The photosensitive drum 2 is driven to rotate by a driving member (not shown) in a clockwise direction in Fig. 7. Around the photosensitive drum 2, a cleaning member 6, a charging roller 3, and a developing unit 4 are arranged in this order in the direction of rotation.

[0022] The cleaning member 6 removes the toner agent remaining on the photosensitive drum 2 after the toner image formed on the photosensitive drum 2 is transferred onto the intermediate transfer belt 8 .

[0023] Furthermore, the charging roller 3 uniformly charges the surface of the photosensitive drum 2. After the surface of the photosensitive drum 2 is charged by the charging roller 3, the surface of the photosensitive drum 2 is exposed to laser light from a scanner unit (exposure means) 7. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 2. In this embodiment, the scanner unit 7 is disposed below the cartridge 1.

[0024] The developing unit 4 supplies a toner agent to the electrostatic latent image formed on the photosensitive drum 2, thereby developing the electrostatic latent image into a toner image.

[0025] When an image is formed on the recording material P, first, an electrostatic latent image formed on the surface of the photosensitive drum 2 by the scanner unit 7 is developed into a toner image by the cartridge 1 and transferred to the intermediate transfer belt 8 .

[0026] The intermediate transfer belt 8 is stretched around a secondary transfer opposing roller 9 and a tension roller 10, and is driven counterclockwise as indicated by the arrow in Fig. 7. Furthermore, a primary transfer roller 5 is disposed inside the intermediate transfer belt 8, facing each photosensitive drum 2, and a transfer bias is applied thereto by a bias application means (not shown).

[0027] For example, when a negatively charged toner agent is used, a positive bias is applied to the primary transfer roller 5, whereby the toner images are sequentially primarily transferred onto the intermediate transfer belt 8. Then, the intermediate transfer belt 8 is transported to a secondary transfer section nipped between the secondary transfer opposing roller 9 and the secondary transfer roller 11 with the four color toner images superimposed on each other.

[0028] At this time, the toner remaining on the intermediate transfer belt 8 after the secondary transfer to the recording material P is removed by the transfer belt cleaning device 12, and the removed toner passes through a waste toner transport path (not shown) and is collected in a waste toner collection container (not shown).

[0029] Meanwhile, in synchronization with the image forming operation described above, the recording material P is conveyed from a paper feed cassette 13 storing the recording material P to a secondary transfer portion by a conveying mechanism including a paper feed roller 14, a pair of registration rollers 16, and the like.

[0030] The sheet feed cassette 13 is configured to be freely detachable from the image forming apparatus 500. After pulling out the sheet feed cassette 13 and removing it from the image forming apparatus 500, the user sets recording materials P of various width sizes in each of the sheet feed cassettes 13A, 13B, and 13C and inserts them into the image forming apparatus 500, thereby completing the supply of the recording materials P.

[0031] The recording materials P stored in the paper feed cassettes 13 and located at the top of the selected paper feed cassette 13 are pressed against the paper feed roller 14 and driven, so that the recording materials P are separated and fed one by one. When manual paper feed is selected, the recording materials P set on the manual feed tray 17 are separated and fed one by one by the paper feed roller 14.

[0032] Then, the recording material P conveyed from the paper feed cassette 13 or the manual feed tray 17 passes through a conveying path 15 and is conveyed to a secondary transfer section by a pair of registration rollers 16. In the secondary transfer section, a positive bias is applied to a secondary transfer roller 11, so that the four-color toner image on the intermediate transfer belt 8 can be secondarily transferred onto the conveyed recording material P.

[0033] Then, the recording material P is fed from the secondary transfer unit, and conveyed to a fixing device 20 through a conveying path 19, where heat and pressure are applied to the image transferred to the recording material P to fix the image onto the recording material P. Thereafter, the recording material P with the fixed toner image is discharged onto a discharge tray 23 by a pair of discharge rollers 22.

[0034] During double-sided printing, the recording material P is sent onto the discharge tray 23 by the pair of discharge rollers 22, and just before the trailing end passes the pair of discharge rollers 22, the rotation of the pair of discharge rollers is reversed, and the recording material P is switched back and introduced into the double-sided conveying path 24. Then, the recording material P is conveyed again to the pair of registration rollers 16 in an inverted state, and thereafter passes through the secondary transfer section, the fixing device 20, and the pair of discharge rollers 22 as described above, and is discharged onto the discharge tray 23.

[0035] (Fixing device 20) Next, the fixing device 20, which is an image heating device, will be described with reference to FIG. 8, a cross-sectional view of the fixing device, and FIG. 9, a cross-sectional view of the pressure releasing mechanism.

[0036] The fixing device 20 is a film heating type heating device. In the fixing device 20, a nip portion N is formed by applying pressure between a pressure roller 201 and a fixing film unit 202, and the toner image is heated by sandwiching and conveying a recording material in the nip portion N. The fixing film unit 202 is composed of a ceramic heater 203 which is a planar heater, a cylindrical fixing film 204 as a fixing member, a heater holder 205 which holds the ceramic heater 203, a fixing flange 206 which regulates the end of the fixing film 204, and a pressure stay 207 which is disposed on the inner side of the fixing film 204 to ensure the strength of the heater holder 205. In addition, the pressure of the nip portion N can be released by a pressure release mechanism 208.

[0037] The fixing device 20 will be described in detail below.

[0038] The ceramic heater 203 is basically composed of a long and thin ceramic substrate and an energized heat generating resistor layer provided on the substrate surface, and is a low heat capacity heater that rises in temperature with a steep rise characteristic as a whole when current is passed through the heat generating resistor layer. The ceramic heater 203 is fitted and supported in a fitting groove 205a provided along the longitudinal direction of the lower surface of the heater holder 205.

[0039] The fixing film 204 is a heat-resistant cylindrical member that transfers heat to the recording material P, and is fitted to the heater holder 205. The fixing film 204 is a film having a four-layer composite structure of a release layer, an elastic layer, a base layer, and an inner surface coating layer. The release layer is a fluororesin material having a thickness of 100 μm or less, preferably 20 to 70 μm. Examples of the fluororesin layer include PTFE and PFA. The elastic layer is a rubber material having a thickness of 1000 μm or less, preferably 500 μm or less, in order to reduce the heat capacity. Examples include silicone rubber and fluororubber. The base layer is a heat-resistant material having a thickness of 100 μm or less, preferably 50 μm or less and 20 μm or more. For example, it is a metal film such as SUS or nickel, or a resin material such as polyimide. The inner surface coating layer is a resin layer having heat resistance. For example, it is polyimide, polyimideamide, PEEK, PTFE, FEP, PFA, etc.

[0040] The pressure stay 207 is a member that provides the heater holder 205 with longitudinal strength by pressing against the rear surface of the heater holder 205 and also corrects the heater holder 205 .

[0041] The heater holder 205 is a heat-resistant and heat-insulating member provided inside the fixing film 204, and is made of a material having good insulating and heat-resistant properties, such as phenol resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, PES resin, PPS resin, PFA resin, PTFE resin, LCP resin, etc. A fitting groove 205a is provided so as to be able to support the ceramic heater 203, and a nip portion N is formed by being pressed against the pressure roller 201 via the fixing film 204.

[0042] The fixing flanges 206 are fitted into both ends of a pressure stay 207 to guide the rotation of the fixing film 204 and prevent the fixing film 204 from slipping out.

[0043] The pressure roller 201 is composed of a core and a heat-resistant elastic material layer such as silicone rubber, fluororubber, or fluororesin that is molded and coated concentrically around the core into a roller shape, and has a release layer on the surface. The release layer is a fluororesin material with a thickness of 100 μm or less, preferably 20 to 70 μm. Examples of the fluororesin layer include PTFE and PFA. Bearing members 210 made of heat-resistant resin such as PEEK, PPS, or LCP are attached to both ends of the core and are arranged to be rotatably held by the side plates 209.

[0044] In this embodiment, the fixing film 204 is pressed against the pressure roller 201 by the pressure member 211 to form the nip N. As shown in FIG. 9, the pressure member 211 stretches a spring 212 as a pressure elastic member, and presses (pushes) the fixing flange 206 toward the pressure roller 201 by the elastic force of the spring 212.

[0045] (Pressure release mechanism 208) The pressure release mechanism 208, which is a switching mechanism, moves the pressure member 211 as described above to switch the nip portion N between a pressure state and a pressure release state. In this embodiment, the pressure release mechanism 208 is configured to bring the pressure roller 201 into contact with the fixing film 204 and separate the pressure roller 201 from the fixing film 204, but may be configured to change the pressure between the pressure roller 201 and the fixing film 204. Such a pressure release mechanism 208 includes a cam 213 and a cam contact surface 211a that contacts the cam surface of the cam 213 formed on the pressure member 211. The cam 213 is driven via the drive switching device 300 by a motor 302 as a driving source provided in the image forming apparatus 500, which will be described later, and pressurizes and releases the pressure of the nip portion N by bringing the cam surface into contact with or separating it from the cam contact surface 211a of the pressure member 211.

[0046] 9, when the nip portion N is pressed, the phase of the cam 213 is set so as not to come into contact with the cam contact surface 211a of the pressing member 211. As a result, the pressing member 211 presses the fixing flange 206 by the elastic force of the spring 212, and the nip portion N is pressed.

[0047] On the other hand, when pressure is released, the phase of the cam 213 rotates approximately 180° from the state in Fig. 9, and the cam 213 comes into contact with the cam contact surface 211a of the pressure member 211, pushing up the pressure member 211 against the elastic force of the spring 212. This releases the pressure at the nip portion N.

[0048] The fixing device 20 configured as described above is attached to the image forming apparatus 500 and driven by the drive switching device 300. The drive switching device 300 is provided near the fixing device 20 attached to the image forming apparatus 500, and is connected to or disconnected from gears serving as each drive unit provided in the fixing device 20 when the fixing device 20 is attached to or detached from the image forming apparatus 500.

[0049] 10, which is a side view of the fixing device 20 facing the drive switching device 300, the fixing device 20 includes a pressure roller gear 214 and a cam gear 215 as respective drive units. The pressure roller gear 214 is a conveyance drive unit that transmits drive to the pressure roller 201 as a member that conveys the recording material at the nip portion N. The cam gear 215 is a pressure release drive unit that transmits drive to the cam 213 of the pressure release mechanism 208. These gears 214 and 215 are connected to each other so as to be able to transmit drive by respective drive paths of the drive switching device 300, which will be described below, and the drive is transmitted to each of them in accordance with the operation of the drive switching device 300.

[0050] (Drive switching device 300) Next, the drive switching device 300 will be described using the perspective view of the drive switching device 300 in Fig. 11. Fig. 11a is a perspective view of the entire drive switching device 300. Fig. 11b is a perspective view showing the drive train of the drive switching device 300 together with the pressure roller gear 214 and the cam gear 215 of the fixing unit 20, with the drive cover 306 omitted so that it is easy to understand.

[0051] In the drive switching device 300, a motor 302 as a drive source and a motor gear 302a are attached to a drive support frame 307, and drive is transmitted to an input gear 101 of the one-way clutch unit 100. As a transmission path from the one-way clutch unit 100 to the pressure roller gear 214, a swing center gear 309 and a swing gear 310 are provided in a swing unit 308. As a transmission path from the one-way clutch unit 100 to the cam gear 215, an idler gear 311, a pendulum gear 312, and idler gears 313, 314, and 315 are provided in this order. A drive cover 306 supports one end of each of the arranged gears in the axial direction.

[0052] Since the conveying operation for conveying the recording material rotates at high speed for a long time, it is necessary to reduce the operating noise generated by the drive unit. For this reason, all the drive gears in the transmission path from the motor gear 302a to the pressure roller gear 214, including the input gear 101 and output gear 103 of the one-way clutch unit 100, are made up of helical gears.

[0053] Motor 302 is a DC brushless motor capable of forward and reverse rotation, and is positioned and fixed to the rear side of drive support frame 307. Motor 302 is driven to rotate by receiving power from a power source (not shown). Note that motor 302 is not limited to a DC brushless motor, and may be another motor such as a stepping motor as long as it can rotate forward and reverse.

[0054] The drive switching device 300 switches between driving the pressure roller 201 and the pressure release mechanism 208 by the forward and reverse rotation of the motor 302 via a pendulum gear 312 and a one-way clutch unit 100, which will be described later.

[0055] (Pendulum Gear 312) The pendulum gear 312 will be described with reference to the pendulum gear configuration diagram in Fig. 12 and the operation diagram of the pendulum gear 312 in Fig. 13. As shown in Fig. 12a, the pendulum gear 312 is composed of a gear member 318, a holder member 319, and an elastic member 320. The gear member 318 is formed in a cylindrical shape, with gear teeth formed on the outer circumferential surface, and meshes with the idler gears 311, 313 as shown in Fig. 13a.

[0056] The holder member 319 has a circular rib 319a inserted into and fitted within an inner circumferential surface 318a of the gear member 318, thereby supporting the gear member 318 so as to be capable of rotating.

[0057] 12b, the elastic member 320 is fixed to the holder member 319 and elastically biases the inner circumferential surface 318b of the large diameter portion of the gear member 318 (arrow L). When the gear member 318 is caused to oscillate, a rotational load is applied to the gear member 318, thereby generating an oscillating force in the pendulum gear 312.

[0058] The holder member 319 is formed with an elongated hole 319b that penetrates the axial direction of the gear member 318 and is long in a direction perpendicular to the axial direction. As shown in Fig. 13, a shaft 321 protruding from the support frame 307 is passed through the elongated hole 319b, thereby movably holding the holder member 319. The holder member 319 is also provided with a protrusion 319c that extends into a restricting groove 317 formed in the drive cover 306, as shown in Fig. 13b. The restricting groove 317 restricts the swing range of the pendulum gear 312 by engaging with the protrusion 319c.

[0059] When the idler gear 311 rotates in the direction of arrow J in Fig. 13a, a rotational driving force is transmitted to the gear member 318 in the pendulum gear 312 which meshes with the idler gear 313. Even if the pendulum gear 312 is in the position shown in Fig. 13c, the gear member 318 can swing between the long hole portion 319b and the shaft 321 due to the rotational load from the elastic member 320 and the driving force that the gear member 318 receives from the idler gear 311, so that the gear member 318 moves to the position shown in Fig. 13a, meshes with the idler gear 313, and transmits the driving force.

[0060] Also, as shown in FIG. 13c, when idler gear 311 rotates in the direction of arrow K, pendulum gear 312 swings from the position shown in FIG. 13a to the position shown in FIG. 13c, and is no longer engaged with idler gear 313, cutting off transmission.

[0061] (One-way clutch unit 100) Figures 1a and 1b are perspective views of the one-way clutch unit 100. Figures 5a and 5b are perspective views of the drive transmission member 102.

[0062] 1a and 1b, one-way clutch unit 100 has an input gear 101, a drive transmission member 102, and an output gear 103. The input gear 101 and the output gear 103 are fitted onto a shaft 104, and the drive transmission member 102 is inserted onto the shaft 104 with a clearance therebetween. That is, in one-way clutch unit 100, driving force is applied from motor 302 to input gear 101, and the one-way clutch unit 100 switches between transmitting and not transmitting the driving force from the input gear 101 to the output gear 103.

[0063] The input gear 101 has a tooth surface 101d formed on its outer periphery, and a concave shape formed by an annular rib (cylindrical portion including a rim) 101g. Three engagement ribs 101e are provided in a space SP1 surrounded by the annular rib 101g of the input gear 101, and serve as an engagement surface with an input-side forward rotation engagement portion 102b of the drive transmission member 102, which will be described later. The engagement ribs 101e engage with the drive transmission member 102, as will be described later, and serve as a restriction portion that restricts the rotation of the drive transmission member 102.

[0064] The output gear 103 is also formed in a concave shape by an annular rib, and a tooth surface 103c is formed on the outer periphery of the annular rib. The output gear 103 has a cylindrical housing portion that houses the drive transmission member 102. The drive transmission member 102 is attached to the housing portion. The inner peripheral surface of the annular rib 103e is provided with a surface 103a that abuts against a biasing portion 102a arranged on the drive transmission member 102 described later. Similarly, the inner periphery of the annular rib is provided with a tooth surface 103b that is an annular first tooth surface that engages with an output side positive rotation time engagement portion 102c that is an annular second tooth surface of the drive transmission member 102 described later. The first tooth surface and the second tooth surface each have a concave-convex shape. In this embodiment, the annular rib is an opposing surface that abuts against the axial end surface of the housing portion of the output gear 103.

[0065] As shown in Fig. 5a, the surface of the drive transmission member 102 facing the input gear 101 is provided with three input-side forward rotation engaging portions 102b that engage during forward rotation (the direction of the arrow C in Fig. 3a), an input-side inclined surface 102d that smoothly connects to the engaging portions, and an input-side reverse rotation engaging portion 102e that engages during reverse rotation (the direction of the arrow D in Fig. 3b). This input-side inclined surface 102d plays the role of a cam portion for converting the rotational force of the input gear into a force that moves the drive transmission member 102 in the axial direction.

[0066] 5b, the surface of the drive transmission member 102 facing the output gear 103 is provided with an output-side forward rotation engaging portion 102c that engages during forward rotation, and an output-side inclined surface 102f that moves the drive transmission member 102 toward the input gear 101 during reverse rotation. In addition, the drive transmission member 102 has biasing portions 102a arranged at equal intervals on its outer periphery, which come into contact with an inner peripheral surface 103a of an annular rib of the output gear 103.

[0067] The operation of the one-way clutch 100 during forward and reverse rotation will be described in detail with reference to FIG.

[0068] Fig. 3a is a cross-sectional view for explaining the process of changing from disconnection to connection. As shown in Fig. 3a, when the input gear 101 rotates in the C direction in the disconnected state, the engagement rib 101e provided on the input gear 101 presses the input surface inclined portion 102d of the drive transmission member 102, and urges the drive transmission member 102 toward the output gear 103 (arrow H direction). The engagement rib 101e of the input gear 101 engages with the input side forward rotation engagement portion 102b (shown in Fig. 5a) of the drive transmission member 102, and the tooth surface 103b of the output gear 103 engages with the output side forward rotation engagement portion 102c of the drive transmission member 102, respectively, completing the drive connection.

[0069] Next, the drive connection release will be described. FIG. 3b is a cross-sectional view explaining the process from connection to release. As shown in FIG. 3b, when the input gear 101 rotates in the D direction in the connected state, the engagement rib 101e provided on the input gear 101 presses the reverse rotation engagement portion 102e (shown in FIG. 5b) of the drive transmission member 102, causing the drive transmission member 102 to rotate in the D direction. The drive transmission member 102 rotated in the D direction moves toward the input gear 101 (arrow I direction) due to the inclined surface formed on the cam surface 103b of the output gear 103 and the output side inclined surface 102f (shown in FIG. 5b) arranged on the drive transmission member 102, completing the drive connection release operation. When the drive connection is released, the input gear 101 rotates but the output gear 103 does not rotate. As a result, the annular rib and the axial end surface of the housing portion of the output gear 103 rub against each other.

[0070] (Configuration for preventing adhesion of viscous grease to drive transmission components) Next, the shape of the input gear 101, which is a feature of the present invention, and its effects will be described.

[0071] 1, the input gear 101 has a recess (recess) 101f between a hole (bearing) 101b into which the rotating shaft 104 fits and an abutment surface (contact surface) 101c against which the drive transmission member 102 abuts.

[0072] The effect of the recessed shape 101f of this embodiment will be described with reference to FIG.

[0073] As described above, in order to reduce the operating noise during the conveying operation, the input gear 101 of the one-way clutch unit 100 is configured as a helical gear. Therefore, a force in the thrust direction is generated in both forward and reverse rotation. For example, if the twist direction of the input gear 101 is set to the right, the direction of the force generated by the rotation is the direction of arrow E in the rotation in the direction in which the drive is transmitted in Fig. 3a, and the direction of arrow F in the rotation in the direction in which the drive is cut off in Fig. 3b.

[0074] In order to prevent the end face of the input gear 101 from being scraped when the input gear 101 rotates with a force applied in the direction of arrow E, viscous grease is applied to the end face 101a of the input gear 101.

[0075] As described above, the grease G applied to the gear end face of the input gear 101 passes through the gap 105 between the rotation shaft 104 of the input gear 101 and the hole 101b of the input gear 101 and enters the inside of the one-way clutch unit 100.

[0076] The viscous grease G that has entered the inside of the one-way clutch unit 100 advances to the surface of the input gear 101 that is connected to the hole 101b of the input gear 101.

[0077] In the conventional configuration shown in FIG. 2, the viscous grease G reaches the surface 101c with which the drive transmission member 102 of the input gear 101 comes into contact, as shown in FIG. 6a.

[0078] As a result, as described above, the input gear 101 rotates in the drive release direction (Figure 3b), and the drive transmission member 102 moves toward the input gear 101 (in the direction of arrow I), causing the drive transmission member 102 to be adhered to the input gear 101 by the viscous grease G.

[0079] When the input gear 101 is rotated in the direction of connecting the drive (the direction of arrow C in Figure 3a), the adhesive force of the drive transmission member 102 to the input gear 101 becomes greater than the force with which the engagement rib 101e of the input gear 101 pushes up on the input surface inclined portion 102d of the drive transmission member 102, and the drive transmission member 102 is unable to move toward the output gear 103 (the direction of arrow H in Figure 3a), and the one-way clutch unit 100 is unable to perform the transmission switching operation.

[0080] In contrast, in the present embodiment shown in FIG. 6b, a concave shape 101f is formed in the input gear 101. That is, the concave shape 101f is recessed in the axial direction relative to the abutting surface. In this embodiment, the concave shape 101f is recessed in a stepped manner relative to the abutting surface. The recessing method is not limited to this configuration. In the configuration in which the concave shape 101f is formed in the input gear 101, the viscous grease G that has entered the inside of the one-way clutch unit 100 reaches the concave shape 101f of the input gear 101, but does not reach the surface 101c with which the drive transmission member 102 abuts. Therefore, the viscous grease G does not adhere to the drive transmission member 102 and does not hinder the operation of the drive transmission member 102, so that the transmission switching operation of the one-way clutch unit 100 can be stably performed.

[0081] It is desirable that the volume of the space SP2 determined by the depth and outer diameter of the concave shape 101f of the input gear 101 be such that all of the viscous grease G applied to the end face 101a of the input gear 101 can be accommodated, but this is not limited to the above.

[0082] In this manner, by adopting this embodiment, it is possible to stably perform the transmission switching operation of the one-way clutch unit and suppress wear on the gear end faces.

[0083] In this embodiment, the input gear 101 and the output gear 103 are described as helical gears, but they may be spur gears.

[0084] In addition, the relationship between the input gear and the output gear may be reversed from that of this embodiment. That is, the present invention is effective even if the gear train is configured such that the output gear of this embodiment serves as the input gear, and the input gear of this embodiment serves as the output gear. [Explanation of symbols]

[0085] 20 Fixing device 100 One-way clutch unit 101 Input Gear 101f concave shape 102 Drive transmission member 103 Output Gear 104 Rotating shaft 300 Drive switching device G Viscous grease

Claims

1. the recording medium comprises a first rotating body and a second rotating body which form a nip portion for sandwiching and transporting a recording material in order to heat a toner image formed on the recording material; a drive source; a one-way clutch unit which transmits a driving force for rotating the first rotating body when the drive source rotates in a forward direction and does not transmit a driving force for rotating the first rotating body when the drive source rotates in a reverse direction; and a switching mechanism which changes a pressure force between the first rotating body and the second rotating body or separates the first rotating body and the second rotating body from each other when the drive source rotates in a reverse direction; In the image heating apparatus, the one-way clutch unit includes a shaft, an input gear supported by the shaft and receiving a driving force from the driving source, an output gear supported by the shaft and outputting the driving force, and a drive transmission member supported by the shaft and switching between transmission and non-transmission of the driving force from the input gear to the output gear by moving in the axial direction of the shaft, the output gear has a cylindrical housing portion that houses the drive transmission member therein so as to be movably axially movable, and an annular first tooth surface that is made up of a plurality of projections and recesses and that meshes with the first tooth surface and is formed on the drive transmission member when the drive source rotates forward, and that does not mesh with the first tooth surface and moves the drive transmission member away when the drive source rotates reversely, the input gear has an abutment surface against which the drive transmission member abuts, an end surface that abuts against the shaft, and a restricting portion that extends from the shaft toward an outer periphery of the input gear and engages with the drive transmission member to restrict rotation of the drive transmission member, and grease is applied to the end surface; the drive transmission member has a cam portion that engages with the restricting portion to convert a rotational force of the input gear into a force that moves the drive transmission member in the axial direction, The input gear has an annular recessed portion recessed in the axial direction from the abutment surface, the recessed portion being provided between the shaft and the abutment surface and facing the shaft.

1. An image heating apparatus comprising:

2. an image heating device including a first rotating body and a second rotating body which form a nip portion which sandwiches and conveys a recording material in order to heat a toner image formed on the recording material; a drive source; a one-way clutch unit which transmits a driving force for rotating the first rotating body when the drive source rotates forward and does not transmit the driving force for rotating the first rotating body when the drive source rotates reversely; and a switching mechanism which changes a pressure force between the first rotating body and the second rotating body or separates the first rotating body and the second rotating body from each other when the drive source rotates reversely, wherein the one-way clutch unit includes a shaft, an input gear supported by the shaft and receiving the driving force of the drive source, an output gear supported by the shaft and outputting the driving force, and a drive transmission member supported by the shaft and switching between transmission and non-transmission of the driving force from the input gear to the output gear by moving in the axial direction of the shaft; the input gear has a cylindrical housing portion that houses the drive transmission member therein so as to be movably axially moved, and an annular second tooth surface that is configured with a plurality of protrusions and recesses and that meshes with a first tooth surface formed with a plurality of protrusions and recesses on the drive transmission member when the drive source rotates forward, and that does not mesh with the first tooth surface and moves the drive transmission member away when the drive source rotates reversely, the output gear has an abutment surface against which the drive transmission member abuts, an end surface that abuts against the shaft, and a restricting portion that extends from the shaft toward an outer periphery of the output gear and engages with the drive transmission member to restrict rotation of the drive transmission member, and grease is applied to the end surface; the drive transmission member has a cam portion that engages with the restricting portion to convert a rotational force of the input gear into a force that moves the drive transmission member in the axial direction, The output gear has an annular recessed portion recessed in the axial direction from the abutment surface, the recessed portion being provided between the shaft and the abutment surface and facing the shaft.

1. An image heating apparatus comprising:

3. 3. The image heating apparatus according to claim 1, wherein the drive transmission member has a biasing portion that abuts against an inner surface of the housing portion and biases the drive transmission member toward the shaft.

4. 4. The image heating apparatus according to claim 1, wherein the abutting surface and the recessed portion are concentrically formed in annular shapes.

5. 5. The image heating apparatus according to claim 1, wherein the abutting surface and the recessed portion have a stepped shape.

6. 6. The image heating apparatus according to claim 1, wherein the second rotating body is a belt, and the belt is rotated by receiving a driving force from the first rotating body.

7. 7. The image heating apparatus according to claim 6, further comprising a planar heater for heating the belt, the second rotating body pressing the heater through the belt.

8. The grease is a viscous grease.

8. The image heating apparatus according to claim 1, wherein the heating medium is a heat exchanger.

9. The end surface is a surface where the input gear and the end of the shaft come into contact with each other in a direction intersecting with the axial direction.

9. The image heating apparatus according to claim 1, wherein the heating medium is a heat exchanger.

10. the shaft has a shaft portion and a second restricting portion that the input gear abuts against when the input gear receives a force directed in a direction opposite to the drive transmission member, and that restricts movement of the input gear; The end surface is a contact surface between the input gear and the second restriction portion.

9. The image heating apparatus according to claim 1, wherein the heating medium is a heat exchanger.

11. The input gear is composed of a helical gear.

11. The image heating apparatus according to claim 1,

Images