Rotation detection mechanism, heating device, fixing device, image forming apparatus

Abstract

To provide a rotation detection mechanism that can detect presence or absence of rotation on both sides in an axial direction of a rotating body with a simple mechanism.SOLUTION: A rotation detection mechanism 40 comprises: a rotation shaft 41 that is rotated following rotation of a fixing sleeve 20; and an optical sensor 44 that detects the rotation of the rotation shaft 41. The rotation shaft 41 includes a first gear to be driven 42A that is provided on one side in an axial direction C of the rotation shaft and transmitted with driving force from the fixing sleeve 20, and a second gear to be driven 42B that is provided on the other side in the axial direction C of the rotation shaft and transmitted with the driving force from the fixing sleeve 20. With the rotation of the fixing sleeve 20, the first gear to be driven 42A and the second gear to be driven 42B are transmitted with the driving force from the fixing sleeve 20 in different phases.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a rotation detection mechanism, a heating device, a fixing device, and an image forming apparatus.

Background Art

[0002] In recent years, in order to save energy and increase the speed of a fixing device, a low heat capacity fixing device provided with a fixing sleeve made of a thin film is known. The fixing device heats a rotating fixing sleeve with a heating member to raise the temperature to the fixing temperature.

[0003] In such a fixing device, when the rotation of the fixing sleeve stops due to an abnormality in the device or the like, only a part of the circumferential direction of the fixing sleeve is intensively heated, and the fixing sleeve abnormally heats up. To prevent this, a rotation detection mechanism for detecting the rotation of the fixing sleeve is provided. When the rotation detection mechanism detects the stop of the rotation of the fixing sleeve, control is performed to stop the heating by the heating member.

[0004] For example, in Patent Document 1 (Japanese Patent No. 6428700), a pulse plate is provided on a rotating shaft that rotates passively as the fixing sleeve rotates. As the pulse plate rotates, the light-shielding portion of the pulse plate sequentially passes through the rotation detection sensor, so that the detection state and the non-detection state of the rotation detection sensor are switched, and the rotation of the fixing sleeve is detected.

[0005] The rotation detection mechanism including this pulse plate or the like is provided at both ends of the fixing sleeve. Thereby, even when the fixing sleeve breaks in the middle and only one side rotates, it is possible to detect that one side of the fixing sleeve is not rotating by one of the rotation detection mechanisms.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a rotation detection mechanism capable of detecting the presence or absence of rotation on both sides of a rotating body with a simple configuration.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention provides a rotation detection mechanism including a driven rotating body and a detection member for detecting the rotation of the driven rotating body. The driven rotating body includes a first transmission part provided on one side in the axial direction and configured to transmit a driving force from a rotating body, and a second transmission part provided on the other side in the axial direction and configured to transmit a driving force from the rotating body. Due to the rotation of the rotating body, the first transmission part and the second transmission part receive driving forces from the rotating body at different phases, causing the driven rotating body to rotate passively.

Advantages of the Invention

[0008] According to the rotation detection mechanism of the present invention, the presence or absence of rotation on both sides of the rotating body can be detected with a simple configuration.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

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Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions thereof are appropriately simplified or omitted. In the following description, as an example of an apparatus provided with a rotation detection mechanism, a fixing device as a heating device for fixing a toner image on the surface of a sheet of paper will be described.

[0011] A monochrome image forming apparatus 1 shown in Fig. 1 is provided with a photosensitive drum 10. The photosensitive drum 10 can carry toner as a developer on its surface. The photosensitive drum 10 is a drum-shaped rotating body that can rotate in the direction of the arrow in the figure. Around the photosensitive drum 10, a charging roller 11, a developing device 12 including a developing roller 7, a cleaning blade 13, and the like are provided. The charging roller 11 uniformly charges the surface of the photosensitive drum 10. The developing roller 7 supplies toner to the surface of the photosensitive drum 10. The cleaning blade 13 cleans the surface of the photosensitive drum 10.

[0012] Above the process unit 2, an exposure unit 3 is arranged. The exposure unit 3 emits a laser beam Lb based on image data. This laser beam Lb is irradiated onto the surface of the photosensitive drum 10 via a mirror 14.

[0013] Also, transfer means 15 is arranged at a position facing the photosensitive drum 10. The transfer means 15 includes a transfer charger and transfers the image on the surface of the photosensitive drum 10 to a sheet of paper P.

[0014] The photosensitive drum 10, charging roller 11, process unit 2, transfer means 15, etc. constitute an image forming means for forming an image on a sheet of paper.

[0015] A paper feeding unit 4 is located at the lower part of the image forming apparatus 1. The paper feeding unit 4 includes a paper feed cassette 16, a paper feed roller 17, etc. A registration roller 18 is arranged on the downstream side in the conveyance direction of the paper feed roller 17. The paper feed cassette 16 houses a sheet of paper P as a recording medium. The paper feed roller 17 feeds the sheet of paper P from the paper feed cassette 16 to the conveyance path 5.

[0016] The fixing device 9 has a fixing sleeve 20, a pressure roller 21, etc. The fixing sleeve 20 is heated by a heater (described later) as a heating member. The pressure roller 21 presses the fixing sleeve 20.

[0017] Hereinafter, with reference to FIG. 1, the basic operation of the image forming apparatus 1 will be described.

[0018] When the image forming operation is started, first, the charging roller 11 charges the surface of the photosensitive drum 10. Then, based on the image data, a laser beam Lb is irradiated from the exposure unit 3 onto the photosensitive drum 10. As a result, the potential of the irradiated portion of the photosensitive drum 10 decreases, and an electrostatic latent image is formed on that portion. Toner is supplied to the surface portion of the photosensitive drum 10 on which the electrostatic latent image is formed from the developing device 12, and is visualized as a toner image (developer image). Then, the toner and the like remaining on the photosensitive drum 10 after transfer are removed from the surface of the photosensitive drum 10 by the cleaning blade 13.

[0019] On the other hand, when the image forming operation is started, in the lower part of the image forming apparatus 1, the paper feed roller 17 of the paper feeding unit 4 is rotationally driven, so that the sheet of paper P housed in the paper feed cassette 16 is sent out to the conveyance path 5.

[0020] The paper P fed out onto the conveyance path 5 is timed by the registration roller 18 and conveyed to the transfer section at a timing to face the toner image on the surface of the photoreceptor drum 10. This transfer section is the opposing portion between the transfer means 15 and the photoreceptor drum 10. By applying a transfer bias by the transfer means 15, the toner image is transferred onto the surface of the paper P conveyed to the transfer section.

[0021] The paper P onto which the toner image has been transferred is conveyed to the fixing device 9. The paper P is heated and pressed by the heated fixing sleeve 20 and the pressure roller 21 to fix the toner image on the surface of the paper P. Then, the paper P onto which the toner image has been fixed is separated from the fixing sleeve 20 and conveyed by a pair of conveyance rollers provided on the downstream side of the fixing device 9 and discharged to the paper discharge tray. The paper discharge tray is provided outside the device.

[0022] Subsequently, the configuration of the fixing device will be described in more detail.

[0023] As shown in FIG. 2, the fixing device 9 according to the present embodiment includes an endless fixing sleeve 20, a pressure roller 21 as an opposing member or a pressure member, a heater 22 as a heating member, a heater holder 23 as a holding member, a stay 24 as a support member, a thermistor 25 as temperature detection means, and the like. The pressure roller 21 abuts against the outer peripheral surface of the fixing sleeve 20 to form a fixing nip N as a nip portion. The heater 22 heats the fixing sleeve 20. The heater holder 23 holds the heater 22. The stay 24 supports the heater holder 23 from its back side. The fixing sleeve 20, the pressure roller 21, the heater 22, the heater holder 23, and the stay 24 extend in a direction perpendicular to the plane of FIG. 2, and hereinafter this direction is also referred to as the longitudinal direction of each member or simply the longitudinal direction. This longitudinal direction is also the axial direction of the virtual rotation axis of the fixing sleeve 20 and the width direction of the paper P passed through the fixing device 9. As one aspect of the rotating body provided in the rotation detection mechanism of the present invention, the fixing member provided in the fixing device can be used as this rotating body. In the fixing device 9 of the present embodiment, the fixing sleeve 20, which is a specific example of this fixing member, is provided as the rotating body.

[0024] The fixing sleeve 20 has, for example, a cylindrical substrate made of polyimide (PI) with an outer diameter of 25 mm and a thickness of 40 to 120 μm. On the outermost surface of the fixing sleeve 20, a release layer with a thickness of 5 to 50 μm made of a fluororesin such as PFA or PTFE is formed to enhance durability and ensure release properties. An elastic layer made of rubber or the like with a thickness of 50 to 500 μm may be provided between the substrate and the release layer. Further, the substrate of the fixing sleeve 20 is not limited to polyimide, and may be a heat-resistant resin such as PEEK or a metal substrate such as nickel (Ni) or SUS. The inner peripheral surface of the fixing sleeve 20 may be coated with polyimide, PTFE, or the like as a sliding layer. The fixing sleeve 20 is a member to be heated by the heater 22.

[0025] The pressing roller 21 has, for example, an outer diameter of 25 mm. The pressing roller 21 is composed of a solid iron core metal 21a, an elastic layer 21b, and a release layer 21c. The elastic layer 21b is formed on the surface of the core metal 21a. The elastic layer 21b is formed of silicone rubber and has a thickness of, for example, 3.5 mm. The release layer 21c is formed outside the elastic layer 21b. The release layer 21c is desirably a fluororesin layer with a thickness of about 40 μm in order to enhance the release property of the surface of the pressing roller 21.

[0026] The pressing roller 21 is biased toward the fixing sleeve 20 by a biasing means, and is thereby pressed against the heater 22 via the fixing sleeve 20. Thereby, a fixing nip N is formed between the fixing sleeve 20 and the pressing roller 21. Further, the pressing roller 21 is configured to be rotationally driven by a driving means. When the pressing roller 21 rotates in the direction of the arrow in FIG. 2, the fixing sleeve 20 rotates passively accordingly.

[0027] The heater 22 is a planar heating element provided over the longitudinal direction.

[0028] The heater 22 is composed of a plate-shaped base material 26, a resistive heating element (heating portion) 27, an insulating layer 28, etc. The resistive heating element 27 is provided on the base material 26. The insulating layer 28 covers conductors such as the resistive heating element 27. Also, the heater 22 is in contact with the inner peripheral surface of the fixing sleeve 20 on the insulating layer 28 side, and the heat generated from the resistive heating element 27 is transmitted to the fixing sleeve 20 through the insulating layer 28.

[0029] The heater holder 23 and the stay 24 are arranged on the inner peripheral side of the fixing sleeve 20. The stay 24 is composed of a metal channel material, and both end portions thereof are supported by both side plates of the fixing device 9. The stay 24 supports the heater holder 23 and the heater 22 held by the heater holder 23. Thereby, in a state where the pressure roller 21 is pressed against the fixing sleeve 20, the heater 22 reliably receives the pressing force of the pressure roller 21, and a fixing nip N is stably formed between the fixing sleeve 20 and the pressure roller 21.

[0030] Since the heater holder 23 is likely to become high temperature due to the heat of the heater 22, it is preferably formed of a heat-resistant material. For example, when the heater holder 23 is formed of a heat-resistant resin with low thermal conductivity such as LCP, heat transfer from the heater 22 to the heater holder 23 is suppressed, and the heater 22 can efficiently heat the fixing sleeve 20.

[0031] As shown in FIG. 2, when the fixing device 9 according to the present embodiment starts the printing operation, the pressure roller 21 is rotationally driven, and the fixing sleeve 20 starts to rotate passively. Also, by supplying power to the resistive heating element 27 of the heater 22, the fixing sleeve 20 is heated. Then, in a state where the temperature of the fixing sleeve 20 reaches a predetermined target temperature (fixing temperature), the sheet P carrying the unfixed toner image is conveyed between the fixing sleeve 20 and the pressure roller 21 (fixing nip N). Thereby, the unfixed toner image is heated and pressurized and fixed to the sheet P.

[0032] In the above fixing device 9, a rotation detection mechanism for detecting the rotation operation of the fixing sleeve 20 is provided. This rotation detection mechanism will be described with reference to FIG. 3. In the following description, the left-right direction C in FIG. 3 is referred to as the axial direction of the fixing sleeve 20 and the rotating shaft 41.

[0033] As shown in FIG. 3, the pressure roller 21 is transmitted with a driving force from the motor 51 via a gear or the like provided on its shaft portion. When the pressure roller 21 rotates by the driving force of the motor 51, the fixing sleeve 20 rotates passively.

[0034] Fixing gears 52A and 52B as rotating body gears are provided on both sides in the axial direction of the fixing sleeve 20. The fixing gears 52A and 52B are respectively engaged with the idler gears 53A and 53B.

[0035] The rotation detection mechanism 40 includes a rotating shaft 41 as a driven rotating body, a first driven gear 42A as a first transmitted portion, a second driven gear 42B as a second transmitted portion, a light shielding member 43, and an optical sensor 44 as a detection member. The driven gears 42A and 42B are driven rotating body gears.

[0036] Here, the "driven rotating body" in the present embodiment is a member provided in the rotation detection mechanism, a member that rotates passively with the rotating body and is detected for rotation by the detection member. Further, the "rotating body" in the present embodiment is a member that directly or indirectly rotates the driven rotating body, and is a member to be determined whether both sides in the axial direction are rotating normally or not depending on the presence or absence of rotation of the driven rotating body. Note that although the "driven rotating body" rotates passively due to the rotation of the "rotating body", this "rotating body" may also be configured to rotate passively due to the rotation of other members. The fixing sleeve 20, which is the "rotating body" in the present embodiment, is a member that rotates passively due to the rotation of the pressure roller 21.

[0037] The light-shielding member 43 is provided in the middle of the axial direction of the rotating shaft 41. The light-shielding member 43 has a plurality of light-shielding plates 43a in its circumferential direction. In other words, the light-shielding member 43 has a configuration in which a light-shielding portion provided with the light-shielding plates 43a and a slit portion are alternately provided along its circumferential direction.

[0038] An optical sensor 44 is provided facing the light-shielding member 43. When the light-shielding plate 43a is arranged at the position B in FIG. 3, which is the position on the optical path of the optical sensor 44, the optical sensor 44 changes from the detection state to the non-detection state.

[0039] The detection result of the optical sensor 44 is input to the control unit 90 provided in the image forming apparatus 1. However, the control unit 90 may be provided in the fixing device 9 or may be provided in the rotation detection mechanism 40.

[0040] A first driven gear 42A is provided on one side of the axial direction of the rotating shaft 41, and a second driven gear 42B is provided on the other side.

[0041] The driven gears 42A and 42B mesh with the idler gears 53A and 53B on one side and the other side of the axial direction, respectively.

[0042] As shown in FIG. 4(a), the first driven gear 42A has a first tooth portion 42a in a range of 180 degrees in the circumferential direction, and no tooth portion is provided in the other half range of 180 degrees. Also, as shown in FIG. 4(b), the second driven gear 42B has a second tooth portion 42b in half of the circumferential direction, and no tooth portion is provided in the other half range of 180 degrees. The first tooth portion 42a and the second tooth portion 42b are shifted in phase by 180 degrees, and the phases do not overlap.

[0043] As shown in FIG. 3, when the motor 51 rotates, its driving force is transmitted to the idler gears 53A and 53B via the fixing gears 52A, 52B, etc., and the idler gears 53A and 53B rotate. At this time, as shown in FIGS. 4(a) and 4(b), in the phase where the first driven gear 42A meshes with one of the idler gears 53A, the driving force is transmitted from one of the idler gears 53A and the rotating shaft 41 rotates. On the other hand, as shown in FIGS. 5(a) and 5(b), in the phase where the second driven gear 42B meshes with the other idler gear 53B, the driving force is transmitted from the other idler gear 53B and the rotating shaft 41 rotates.

[0044] As shown in FIG. 3, when the rotating shaft 41 rotates, the light shielding member 43 rotates accordingly. Then, when the light shielding member 43 rotates, the light shielding plate 43a intermittently passes through position B. Thereby, the optical sensor 44 alternately switches between the detection state and the non-detection state.

[0045] As described above, according to the present embodiment, the driven gears 42A and 42B of the rotating shaft 41 for rotating the light shielding member 43 are continuously (that is, continuously for 360 degrees or more) rotated by transmitting driving forces from the respective idler gears 53A and 53B at different phases. Therefore, when either one or both of the idler gears 53A and 53B do not rotate, the rotation of the rotating shaft 41 also stops. That is, when the rotation of one side or the other side of the fixing sleeve 20 stops, the rotation of the rotating shaft 41 also stops. In this case, the optical sensor 44 continues to be in either the detection normal state or the non-detection state. Thereby, the control unit 90 can detect that the rotating shaft 41 is not rotating, that is, the fixing sleeve 20 is not rotating normally. When the control unit 90 detects the stop of the rotating shaft 41, it stops the power supply to the heater 22. Therefore, when any abnormality occurs in the fixing sleeve 20 and it does not rotate, the heating of the fixing sleeve 20 by the heater can be stopped to prevent excessive heating of the fixing sleeve 20.

[0046] Thus, in this embodiment, even when only one side of the fixing sleeve 20 stops rotating, the optical sensor 44 can detect the stop of the rotation and the control unit 90 can stop the energization of the heater 22. Therefore, for example, even when the fixing sleeve 20 breaks in the middle in the axial direction and only one side continues to rotate, it is possible to prevent the heater 22 from continuously heating the stopped side and causing overheating. In one embodiment of the present invention, the first driven gear 42A and the second driven gear 42B transmit driving forces in different phases and the rotating shaft 41 rotates. This "different phase" means that the ranges of the phases in which the first driven gear 42A and the second driven gear 42B are directly or indirectly transmitted with driving forces from the fixing sleeve 20 (rotating body) do not match, and a part of them may overlap. Specifically, it means that the circumferential range in which the member (idler gear 53A in this embodiment) that directly transmits the driving force to the first driven gear 42A meshes with the first driven gear 42A is different from the circumferential range in which the member (idler gear 53B in this embodiment) that directly transmits the driving force to the second driven gear 42B meshes with the second driven gear 42B. However, when only one of the first driven gear 42A and the second driven gear 42B is transmitted with the driving force, the circumferential ranges in which the first tooth portion 42a of the first driven gear 42A and the second tooth portion 42b of the second driven gear 42B are provided are set so that the rotating shaft 41 does not continuously rotate by 360 degrees or more. This circumferential direction is the direction along the rotation direction of the rotating body or the like, and is the direction in which the teeth such as the first tooth portion 42a are arranged side by side.

[0047] Compared with the configuration in which detection mechanisms for detecting the rotation of the fixing sleeve 20 are provided at both ends of the fixing sleeve 20, in this embodiment, since the above-described effects can be obtained by one optical sensor 44, the cost of the rotation detection mechanism 40 can be reduced. Further, compared with a configuration in which there are a plurality of detection mechanisms, a failure is less likely to occur and the reliability of the device is improved.

[0048] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0049] In the above embodiment, the heating member is a planar heater having a resistance heating element, but it may also be a halogen heater, a carbon heater, or a heater of the IH (induction heating) system. In this case, a nip forming member that forms a fixing nip N between the heating member and the pressure roller 21 via the fixing sleeve 20 can be provided. In particular, when an IH system heater is adopted for the heating member, due to the size of the coil portion of the heater, the heater and the thermistor 25 will be arranged at different positions in the circumferential direction of the fixing sleeve 20. Therefore, in this case, if the rotation detection mechanism cannot detect the rotation stop of the fixing sleeve 20, it is often the case that the thermistor 25 cannot detect the abnormal temperature rise of the fixing sleeve 20. For this reason, it is preferable to provide the rotation detection mechanism of the present invention in such a heating device.

[0050] In the above embodiment, an optical sensor and a light-shielding member are exemplified as a combination of a rotating body that rotates integrally with the rotating shaft and a detection mechanism that detects the rotation of the rotating body, but the present invention is not limited thereto. For example, the rotation detection mechanism 40 of the embodiment shown in FIG. 6 includes a magnetic member 45 and a magnetic sensor 46 as a detection member instead of the optical sensor and the light-shielding member.

[0051] The magnetic member 45 is provided on the rotating shaft 41 and rotates integrally with the rotation of the rotating shaft 41. The magnetic member 45 alternately has a magnetic body 45a as a magnetic portion and a non-magnetic body 45b as a non-magnetic portion in the circumferential direction.

[0052] When the rotating shaft 41 rotates, the magnetic body 45a and the non-magnetic body 45b alternately pass through the position B. As a result, the magnetic sensor 46 alternately switches between a detection state and a non-detection state, and the control unit 90 can detect the rotation of the fixing sleeve 20. According to the configuration of the present embodiment, accurate detection is possible even in an environment where false detection occurs in the optical sensor due to paper dust or oil. Also, similar to the above embodiment, one magnetic sensor 46 can detect both cases where the rotation on either side of the fixing sleeve 20 stops.

[0053] In addition, although the optical sensor 44 shown in FIG. 3 is a transmissive sensor, it may also be a reflective optical sensor. Further, instead of the light shielding plate 43a provided on the rotation axis 41 in FIG. 3, a contact portion may be intermittently provided in the circumferential direction of the rotation axis 41, and the detection member may be a contact type sensor. That is, the detection member may be configured to change the detection state by switching between contact and non-contact with the detection member of the contact portion.

[0054] In the above description, the case where the first tooth portion 42a provided on the first driven gear 42A and the second tooth portion 42b provided on the second driven gear 42B are each provided in a range of 180 degrees in the circumferential direction has been shown, but the present invention is not limited to this. That is, as long as the rotation of the rotation axis 41 does not stop, the range of each tooth portion may be made smaller than 180 degrees. On the other hand, if the range of each tooth portion is made larger than 180 degrees or the like so that there is a phase where the tooth portions overlap, the driving force will be transmitted to the rotation axis 41 from two locations. This may cause an increase in the rotational load and abnormal noise. On the other hand, by providing the respective tooth portions 42a and 42b in a range where the phases of the respective tooth portions 42a do not overlap and the rotation axis 41 can continue to rotate, an increase in the rotational load and the occurrence of abnormal noise can be prevented, which is preferable.

[0055] An example of the phases of the first tooth portion 42a provided on the first driven gear 42A and the second tooth portion 42b provided on the second driven gear 42B overlapping is shown in FIG. 7. In FIGS. 7(a) and 7(b), the first tooth portion 42a provided on the first driven gear 42A and the second tooth portion 42b provided on the second driven gear 42B are each provided in a range of 240 degrees in the circumferential direction, and the range where the two tooth portions overlap is 120 degrees. Further, an example of the case where the phases of the first tooth portion 42a provided on the first driven gear 42A and the second tooth portion 42b provided on the second driven gear 42B do not overlap and the ranges of the respective tooth portions are different is shown in FIG. 8. The first tooth portion 42a in FIG. 8(a) is provided in a range of 240 degrees in the circumferential direction, and the second tooth portion 42b in FIG. 8(b) is provided in a range of 120 degrees in the circumferential direction. These ranges of the tooth portions are examples, and the tooth portions can be provided in an appropriate required range.

[0056] Also, in the above embodiments, as shown in FIG. 3 and the like, the case where the first driven gear 42A and the second driven gear 42B provided on the rotation shaft 41 mesh with the fixing gears 52A and 52B of the fixing sleeve 20 via the idler gears 53A and 53B respectively has been shown. However, the present invention is not limited to this. For example, as shown in FIG. 9, the first driven gear 42A and the second driven gear 42B may be directly meshed with the fixing gears 52A and 52B respectively.

[0057] The image forming apparatus according to the present invention is not limited to the monochrome image forming apparatus shown in FIG. 1, and may be a color image forming apparatus, a copying machine, a printer, a facsimile machine, or a multifunction machine thereof.

[0058] As the recording medium, in addition to the paper P (plain paper), thick paper, postcards, envelopes, thin paper, coated paper (such as coated paper and art paper), tracing paper, OHP sheets, plastic films, prepregs, copper foils, etc. are included.

[0059] Furthermore, the present invention is not limited to the fixing device as described in the above embodiments, and is also applicable to a drying device for drying the ink applied to the paper, and further, a laminator for thermocompression bonding a film as a coating member to the surface of a sheet such as paper, and a heat sealer for thermocompression bonding the seal portion of a packaging material, etc. By applying the rotation detection mechanism of the present invention to such devices, when the rotation on either side in the axial direction of the rotating body stops, the stop of the rotation can be detected.

Description of Reference Numerals

[0060] 1 Image forming apparatus 9 Fixing device (heating device) 20 Fixing sleeve (rotating body) 21 Pressing belt (pressing member) 22 Heater (heating member) 40 Rotation detection mechanism 41 Rotation shaft (driven rotating body) 42A First driven gear (first transmission portion or driven rotating body gear) 42B Second Driven Gear (Second Driven Part or Driven Rotating Gear) 42a First Tooth Part 42b Second Tooth Part 43 Light-Shielding Member 43a Light-Shielding Plate (Light-Shielding Part) 44 Optical Sensor (Detection Member) 45 Magnetic Member 45a Magnetic Body (Magnetic Part) 45b Non-Magnetic Body (Non-Magnetic Part) 46 Magnetic Sensor (Detection Member) 52A, 52B Fixing Gear (Rotating Gear) 53A, 53B Idler Gear 90 Control Unit C Axial Direction of Rotation Axis

Prior Art Documents

Patent Documents

[0061]

Patent Document 1

Claims

1. A driven rotating body, A rotation detection mechanism comprising a detection member for detecting the rotation of the driven rotating body, wherein The driven rotating body is provided on one side in the axial direction thereof, and includes a first transmission part for transmitting a driving force from a rotating body, and a second transmission part provided on the other side in the axial direction and for transmitting a driving force from the rotating body, The rotation of the rotating body causes the first transmission part and the second transmission part to receive the driving force from the rotating body at different phases, and the driven rotating body rotates in a driven manner. A rotation detection mechanism characterized by this.

2. The rotating body has rotating body gears that rotate integrally with the rotating body on both sides in the axial direction, The driven rotating body has driven rotating body gears that rotate integrally with the driven rotating body on both sides in the axial direction, The rotating body gears mesh with the driven rotating body gears via idler gears on both sides in the axial direction, The first transmission part is a first tooth part provided in a partial region in the circumferential direction of the driven rotating body gear on one side in the axial direction, The second transmission part is a second tooth part provided in a partial region in the circumferential direction of the driven rotating body gear on the other side in the axial direction, The first tooth part and the second tooth part mesh with the idler gear at different phases respectively, whereby the driven rotating body is transmitted with a driving force from the rotating body via the idler gear and rotates. The rotation detection mechanism according to claim 1.

3. The rotating body has rotating body gears that rotate integrally with the rotating body on both sides in the axial direction, The driven rotating body has driven rotating body gears that rotate integrally with the driven rotating body on both sides in the axial direction, The rotating body gears mesh with the driven rotating body gears on both sides in the axial direction, The first transmission part is a first tooth part provided in a partial region in the circumferential direction of the driven rotating body gear on one side in the axial direction, The second transmission part is a second tooth part provided in a partial region in the circumferential direction of the driven rotating body gear on the other side in the axial direction, The first tooth part and the second tooth part mesh with the rotating body gear at different phases respectively, whereby the driven rotating body is transmitted with a driving force from the rotating body and rotates. The rotation detection mechanism according to claim 1.

4. The rotation detection mechanism according to claim 2 or 3, wherein the phases in which the first tooth part and the second tooth part are provided do not overlap.

5. The driven rotating body rotates integrally with the driven rotating body and has a plurality of light-shielding parts provided in the circumferential direction of the driven rotating body. The rotation detection mechanism according to any one of claims 1 to 4, wherein the detection member is an optical sensor whose detection state changes depending on the presence or absence of light shielding by the light shielding portion.

6. The driven rotating body has a magnetic portion and a non-magnetic portion that rotate integrally with the driven rotating body alternately in the circumferential direction of the driven rotating body. The rotation detection mechanism according to any one of claims 1 to 4, wherein the detection member is a magnetic sensor.

7. The rotation detection mechanism according to any one of claims 1 to 6, wherein the rotating body is an endless fixing sleeve.

8. A heating device comprising the rotation detection mechanism according to any one of claims 1 to 6, the rotating body, and a heating member.

9. A fixing device comprising the rotation detection mechanism according to claim 7, the rotating body, and a heating member, for thermally fixing toner on a recording medium.

10. An image forming apparatus comprising the fixing device according to claim 9.

Images