JP2020177103A - Image forming apparatus and fixing device - Google Patents

Abstract

To obtain an image forming apparatus that can reduce the number of components.SOLUTION: An image forming apparatus of the present invention comprises: an image forming unit that forms an image on a recording medium by using a developer; and a fixing unit that fixes the developer to the recording medium. The fixing unit includes: a first rotating member that is movable between a first position and a second position; a second rotating member that has a rotator that rotates according to the rotation operation of the first rotating member and has a first area in a first color and a second area provided in parallel in a radial direction, wherein the second area includes first sub areas in a second color and second sub areas in a third color provided in parallel in a circumferential direction; a sensor that irradiates the rotator with light and detects light reflected by the rotator; a movable member; and a support member that rotatably supports the first rotating member and the second rotating member and is movable based on the power of the movable member.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image forming apparatus that forms an image on a recording medium, and a fixing apparatus used in such an image forming apparatus.

In the image forming apparatus, for example, the toner image is transferred to a recording medium, and the toner image is fixed to the recording medium by the fixing portion. For example, Patent Document 1 discloses a fixing device in which a fixing roller and a pressure roller can be separated from each other.

Japanese Unexamined Patent Publication No. 2016-48346

By the way, in general, it is desired that the number of parts of an electronic device is small, and that the number of parts of an image forming apparatus is also reduced.

It is desirable to provide an image forming apparatus and a fixing apparatus capable of reducing the number of parts.

The image forming apparatus according to the embodiment of the present invention includes an image forming portion and a fixing portion. The image forming unit is configured to form an image on a recording medium using a developer. The fixing portion is configured to fix the developer on the recording medium. The fixing portion includes a first rotating member, a second rotating member, a sensor, a movable member, and a support member. The first rotating member is configured to be movable between a first position and a second position. The second rotating member has a rotating body. The rotating body is configured to rotate according to the rotational operation of the first rotating member. The rotating body has a first region of a first color and a second region arranged side by side in the radial direction. The second region includes a first sub-region of the second color and a second sub-region of the third color arranged side by side in the circumferential direction. The sensor is configured to irradiate the rotating body with light and detect the light reflected by the rotating body. The support member rotatably supports the first rotating member and the second rotating member, and is configured to be movable based on the power of the movable member.

The fixing device according to the embodiment of the present invention includes a first rotating member, a second rotating member, a movable member, and a support member. The first rotating member is configured to be movable between a first position and a second position. The second rotating member has a rotating body. The rotating body is configured to rotate according to the rotational operation of the first rotating member. The rotating body has a first region of a first color and a second region arranged side by side in the radial direction. The second region includes a first sub-region of the second color and a second sub-region of the third color arranged side by side in the circumferential direction. The support member rotatably supports the first rotating member and the second rotating member, and is configured to be movable based on the power of the movable member.

According to the image forming apparatus and the fixing apparatus according to the embodiment of the present invention, a support member for rotatably supporting the first rotating member and the second rotating member is provided, and the rotating body is arranged side by side in the radial direction. A first region and a second region of the first color are provided, and a first sub-region of the second color and a second region of the third color are arranged side by side in the circumferential direction in the second region. Since the sub-area of is provided, the number of parts can be reduced.

It is a block diagram which shows one structural example of the image forming apparatus which concerns on one Embodiment. It is a block diagram which shows one configuration example of the ID unit shown in FIG. It is a block diagram which shows one structural example of the fixing part shown in FIG. It is explanatory drawing which shows one operation state of the fixing part shown in FIG. It is explanatory drawing which shows the other operation state of the fixing part shown in FIG. It is a block diagram which shows one structural example of the control system of the image forming apparatus shown in FIG. It is a block diagram which shows one structural example of the main part of the fixing part shown in FIG. It is another block diagram which shows one structural example of the main part of the fixing part shown in FIG. It is another block diagram which shows one structural example of the main part of the fixing part shown in FIG. It is a block diagram which shows one structural example of the gear group of the fixing part shown in FIG. It is a block diagram which shows one structural example of the rotary plate shown in FIG. It is explanatory drawing which shows one operation example of the fixing part shown in FIG. It is another explanatory view which shows one operation example of the fixing part shown in FIG. It is another explanatory view which shows one operation example of the fixing part shown in FIG. It is a timing waveform diagram which shows one operation example of the image forming apparatus shown in FIG. It is a block diagram which shows one structural example of the main part of the fixing part which concerns on a comparative example. It is another block diagram which shows one structural example of the main part of the fixing part which concerns on a comparative example. It is a block diagram which shows one structural example of the rotating plate which concerns on a modification. It is explanatory drawing which shows one operation example of the fixing part which concerns on the modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment>
[Configuration example]
FIG. 1 shows a configuration example of an image forming apparatus (image forming apparatus 1) according to an embodiment of the present invention. The image forming apparatus 1 functions as a printer that forms an image on a recording medium made of, for example, plain paper by using an electrophotographic method. The image forming apparatus 1 includes a medium storage unit 11, a medium sensor 12, a pickup roller 13, a hop sensor 14, a medium supply roller 15A, a retard roller 15B, a transfer roller 16A, a pinch roller 16B, and a registration roller. 17A, pinch roller 17B, writing sensor 18, ID (Image Drum) unit 20, toner accommodating unit 28, LED (Light Emitting Diode) head 29, transfer roller 19, fixing unit 40, and ejection. The sensor 31, the discharge rollers 32A and 32B, and the discharge rollers 33A and 33B are provided. These members are arranged along a transport path 10 for transporting the recording medium 9.

The medium storage unit 11 is configured to store the recording medium 9 on which an image is to be formed. The medium storage unit 11 can store, for example, high-quality paper, recycled paper, glossy paper, matte paper, OHP (Over Head Projector) film, and the like. The medium sensor 12 is configured to detect whether or not the recording medium 9 is stored in the medium storage unit 11.

The pickup roller 13 is a member that takes out the recording media 9 stored in the medium storage unit 11 one by one from the uppermost portion thereof and sends the taken out recording media 9 to the transport path 10. The pickup roller 13 rotates based on the power transmitted from the transfer motor 94B (described later).

The hop sensor 14 is a member that detects whether or not a medium supply operation of sending the recording medium 9 taken out from the medium storage unit 11 to the transport path 10 is being performed. The hop sensor 14 is configured by using, for example, an optical sensor.

The medium supply roller 15A and the retard roller 15B are a pair of rollers that sandwich the transport path 10, and are configured to transport the recording medium 9 along the transport path 10. The medium supply roller 15A rotates based on the power transmitted from the transfer motor 94B (described later), and the retard roller 15B is driven to rotate in response to the rotation of the medium supply roller 15A.

The transfer roller 16A and the pinch roller 16B are a pair of rollers that sandwich the transfer path 10, and are configured to transfer the recording medium 9 along the transfer path 10. The transfer roller 16A rotates based on the power transmitted from the transfer motor 94B (described later), and the pinch roller 16B is driven to rotate in accordance with the rotation of the transfer roller 16A.

The resist roller 17A and the pinch roller 17B are a pair of rollers that sandwich the transport path 10, correct the skew of the supplied recording medium 9, and guide the recording medium 9 to the ID unit 20 along the transport path 10. It is configured as follows. The resist roller 17A rotates based on the power transmitted from the transfer motor 94B (described later), and the pinch roller 17B is driven to rotate in accordance with the rotation of the resist roller 17A.

The writing sensor 18 is a member that detects the passage of the recording medium 9. The writing sensor 18 is used to detect the timing at which the recording medium 9 reaches the ID unit 20. The writing sensor 18 is configured by using, for example, an optical sensor.

The ID unit 20 is configured to form a toner image. The ID unit 20 is configured to be detachable from, for example, the image forming apparatus 1.

The toner accommodating portion 28 is configured to accommodate toner. The toner accommodating portion 28 is configured to be detachable from the ID unit 20.

The LED head 29 is a member that irradiates the photosensitive drum 21 (described later) of the ID unit 20 with light. The LED head 29 is configured by using, for example, a plurality of light emitting diodes and lens arrays arranged side by side in the main scanning line direction (depth direction in FIG. 1), and irradiates the photosensitive drum 21 with light in dot units. It has become.

FIG. 2 shows a configuration example of the ID unit 20. Note that FIG. 2 also shows the toner accommodating portion 28 and the LED head 29 for convenience of explanation. The ID unit 20 includes a photosensitive drum 21, a cleaning member 22, a charging roller 24, a developing roller 25, a developing blade 26, and a supply roller 27.

The photosensitive drum 21 is a member that supports an electrostatic latent image on the surface (surface layer portion). As the photosensitive drum 21, for example, one in which a photosensitive layer including a photoconducting layer and a charge transport layer is formed on the surface of a conductive support made of aluminum or the like can be used. The photosensitive drum 21 rotates counterclockwise in this example by the power transmitted from the drum motor 95B (described later). The photosensitive drum 21 is charged by the charging roller 24 and exposed by the LED head 29. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 21. Then, by supplying toner to the photosensitive drum 21 by the developing roller 25, a toner image corresponding to the electrostatic latent image is formed on the photosensitive drum 21.

The cleaning member 22 is a member that scrapes and cleans the toner remaining on the surface (surface layer portion) of the photosensitive drum 21. As the cleaning member 22, an elastic body such as rubber can be used.

The charging roller 24 is a member that charges the surface (surface layer portion) of the photosensitive drum 21. As the charging roller 24, for example, one in which the surface (peripheral surface) of the conductive metal shaft is coated with a semi-conductive elastic body such as silicon can be used. The charging roller 24 is arranged so as to be in contact with the surface (peripheral surface) of the photosensitive drum 21, and is arranged so as to be pressed against the photosensitive drum 21 with a predetermined pressing amount. The charging roller 24 rotates clockwise in this example according to the rotation of the photosensitive drum 21. A charging voltage is applied to the charging roller 24 by a high-voltage power supply 93 (described later).

The developing roller 25 is a member that supports the toner on the surface. As the developing roller 25, for example, one in which the surface (peripheral surface) of the conductive metal shaft is coated with a semi-conductive elastic body such as urethane rubber can be used. The developing roller 25 is arranged so as to be in contact with the surface (peripheral surface) of the photosensitive drum 21, and is arranged so as to be pressed against the photosensitive drum 21 with a predetermined pressing amount. The developing roller 25 rotates clockwise in this example by the power transmitted from the drum motor 95B (described later). A developing voltage is applied to the developing roller 25 by a high-voltage power supply 93 (described later).

The developing blade 26 abuts on the surface of the developing roller 25 to form a layer (toner layer) made of toner on the surface of the developing roller 25, and regulates (controls, adjusts) the thickness of the toner layer. It is a member. The developing blade 26 is, for example, a plate-shaped elastic member made of stainless steel or the like bent into an L shape. The developing blade 26 is arranged so that its bent portion abuts on the surface of the developing roller 25 and is pressed against the developing roller 25 with a predetermined pressing amount.

The supply roller 27 is a member that supplies the toner contained in the toner accommodating portion 28 to the developing roller 25. As the supply roller 27, for example, one in which the surface (peripheral surface) of the conductive metal shaft is coated with an elastic body can be used. The supply roller 27 is arranged so as to be in contact with the surface (peripheral surface) of the developing roller 25, and is arranged so as to be pressed against the developing roller 25 with a predetermined pressing amount. The supply roller 27 rotates clockwise in this example by the power transmitted from the drum motor 95B (described later). As a result, in the ID unit 20, friction is generated between the surface of the supply roller 27 and the surface of the developing roller 25. As a result, in the ID unit 20, the toner is charged by so-called triboelectric charging. A supply voltage is applied to the supply roller 27 by a high-voltage power supply 93 (described later).

The transfer roller 19 (FIG. 1) is arranged to face the photosensitive drum 21 of the ID unit 20 with the transport path 10 interposed therebetween. A transfer voltage is applied to the transfer roller 19 by a high-voltage power supply 93 (described later). As a result, in the image forming apparatus 1, the toner image formed by the ID unit 20 is transferred onto the surface to be transferred of the recording medium 9.

The fixing unit 40 is a member that fixes the toner image transferred on the recording medium 9 to the recording medium 9 by applying heat and pressure to the recording medium 9.

FIG. 3 shows an example of the configuration of the fixing portion 40. The fixing portion 40 includes a fixing roller 41, a heater 42, a temperature sensor 43, a pressure roller 44, and a fixing belt 45.

The fixing roller 41 is a member that applies heat to the toner on the recording medium 9. As the fixing roller 41, for example, one in which the surface (peripheral surface) of a raw tube such as iron is coated with an elastic body such as silicon rubber can be used. The fixing roller 41 rotates based on the power transmitted from the fixing motor 96B (described later).

The heater 42 is a heat source arranged inside the fixing roller 41 at a position where it does not come into contact with the fixing roller 41. As the heater 42, for example, a halogen heater can be used. The heater 42 generates heat based on the electric power supplied from the heater control unit 97 (described later).

The temperature sensor 43 is arranged at a position in contact with the surface of the fixing roller 41, and is configured to detect the surface temperature of the fixing roller 41. As the temperature sensor 43, for example, a thermistor whose resistance value changes according to the temperature can be used.

The pressure roller 44 is configured to form a pressure contact portion (nip portion) with the fixing roller 41. As the pressure roller 44, for example, one in which the surface (peripheral surface) of a shaft such as iron is coated with an elastic body such as a porous sponge having heat resistance can be used. The pressure roller 44 is configured to be movable between a position where it is pressed toward the fixing roller 41 and a position where it is separated from the fixing roller 41.

FIG. 4 shows an example of the operating state of the fixing portion 40, FIG. 4A shows a state in which the pressurizing roller 44 is pressed toward the fixing roller 41 (nip state S1), and FIG. 4B shows the pressing state. The state in which the roller 44 is separated from the fixing roller 41 (release state S2) is shown. For example, when the image forming apparatus 1 forms an image on the recording medium 9, the operating state of the fixing unit 40 is set to the nip state S1. In this nip state S1, the pressurizing roller 44 is pressed toward the fixing roller 41 with the fixing belt 45 sandwiched by a predetermined pressing amount. As a result, as shown in FIG. 4A, a pressure contact portion N is formed between the fixing roller 41 and the pressure roller 44. The pressure roller 44 is driven to rotate in response to the rotation of the fixing roller 41.

The fixing belt 45 (FIG. 3) is an endless elastic belt, and is stretched (tensioned) by a pressure roller 44 and a guide member (not shown). When the operating state of the fixing portion 40 is the nip state S1, the fixing belt 45 is pressed against the fixing roller 41 by the pressurizing roller 44, and is circulated and conveyed according to the rotation of the fixing roller 41. ..

With this configuration, for example, when the image forming apparatus 1 forms an image on the recording medium 9, the operating state of the fixing unit 40 is set to the nip state S1. Then, as shown in FIG. 3, when the recording medium 9 on which the toner image is transferred is supplied to the fixing unit 40, the fixing unit 40 applies heat and pressure to the recording medium 9. As a result, the toner on the recording medium 9 is heated, melted, and pressurized. As a result, the toner image is fixed on the recording medium 9.

The discharge sensor 31 (FIG. 1) is a member that detects the discharge of the recording medium 9. The discharge sensor 31 is configured by using, for example, an optical sensor.

The discharge roller 32A and the discharge roller 32B are a pair of rollers that sandwich the transport path 10, and are configured to transport the recording medium 9 along the transport path 10. The discharge rollers 32A and 32B rotate based on the power transmitted from the transfer motor 94B (described later).

The discharge roller 33A and the discharge roller 33B are a pair of rollers that sandwich the transport path 10, and are configured to discharge the recording medium 9 to the stacker 34. The discharge rollers 33A and 33B rotate based on the power transmitted from the transfer motor 94B (described later).

(Control system in image forming apparatus 1)
FIG. 5 shows an example of a control system in the image forming apparatus 1. The image forming apparatus 1 includes a communication unit 91, a display operation unit 92, a high-pressure power supply 93, a transfer motor control unit 94A, a transfer motor 94B, a drum motor control unit 95A, a drum motor 95B, and a fixing motor control unit. It includes a 96A, a fixing motor 96B, a heater control unit 97, a sensor 70, and a control unit 99.

The communication unit 91 is configured to perform communication using, for example, USB (Universal Serial Bus) or LAN (Local Area Network). The communication unit 91 is adapted to receive, for example, the print data DP transmitted from the host computer (not shown).

The display operation unit 92 is configured to accept the user's operation and display the operating state of the image forming apparatus 1. The display operation unit 92 is configured by using, for example, a touch panel, various buttons, a liquid crystal display, various indicators, and the like.

The high-voltage power supply 93 has a charging voltage applied to the charging roller 24 of the ID unit 20, a developing voltage applied to the developing roller 25 of the ID unit 20, and a supply roller 27 of the ID unit 20 based on an instruction from the control unit 99. It is configured to generate a supply voltage applied to and a transfer voltage applied to the transfer roller 19.

The transfer motor control unit 94A is configured to control the operation of the transfer motor 94B based on an instruction from the control unit 99. The transfer motor 94B is configured to generate power transmitted to the pickup roller 13, the medium supply roller 15A, the transfer roller 16A, the resist roller 17A, the discharge rollers 32A and 32B, and the discharge rollers 33A and 33B.

The drum motor control unit 95A is configured to control the operation of the drum motor 95B based on an instruction from the control unit 99. The drum motor 95B is configured to generate power transmitted to the photosensitive drum 21, the developing roller 25, and the supply roller 27 of the ID unit 20.

The fixing motor control unit 96A is configured to control the operation of the fixing motor 96B based on an instruction from the control unit 99. The fixing motor 96B is configured to generate power transmitted to the fixing roller 41 of the fixing portion 40. When the image forming apparatus 1 forms an image on the recording medium 9, the fixing motor 96B performs a forward rotation operation based on an instruction from the fixing motor control unit 96A. Further, when the fixing motor 96B sets the operating state of the fixing unit 40 to the release state S2 (FIG. 4B), the fixing motor 96B transiently performs a reverse rotation operation based on an instruction from the fixing motor control unit 96A. ing.

The heater control unit 97 is configured to control the operation of the heater 42 of the fixing unit 40 based on an instruction from the control unit 99.

The sensor 70 is configured to detect the operation of the fixing unit 40. The sensor 70 is a reflection sensor in this example, and detects the operation of the fixing unit 40 by irradiating the rotating plate 65 (described later) of the fixing unit 40 with light and detecting the light reflected by the rotating plate 65. To do. As will be described later, a color pattern PAT including black, gray, and white is formed on the rotating plate 65, and the amount of light reflected by the rotating plate 65 reflects these colors. The sensor 70 detects the moving motion of the pressurizing roller 44 and the rotating motion of the pressurizing roller 44 in the fixing portion 40 by detecting the light reflected by the rotating plate 65.

The sensor 70 includes a light amount control unit 71, a light emitting unit 72, and a light receiving unit 73. The light amount control unit 71 is configured to control the amount of light emitted by the light emitting unit 72 based on an instruction from the control unit 99. The light emitting unit 72 is configured to emit light having a light amount according to an instruction from the light amount control unit 71 toward the rotating plate 65 (described later). The light receiving unit 73 is configured to generate a detection signal DET by photoelectrically converting the light reflected by the rotating plate 65. The sensor 70 supplies the detection signal DET to the control unit 99.

The control unit 99 controls the overall operation of the image forming apparatus 1 by controlling the operation of each block in the image forming apparatus 1. The control unit 99 is configured by using, for example, a processor capable of executing a program. The control unit 99 has a sensor control unit 99A.

The sensor control unit 99A is configured to control the operation of the sensor 70. For example, the sensor control unit 99A emits light to the light emitting unit 72 and detects the operation of the fixing unit 40 based on the detection signal DET supplied from the light receiving unit 73. Specifically, the sensor control unit 99A determines whether the operating state of the fixing unit 40 is the nip state S1 (FIG. 4A) or the release state S2 (FIG. 4B) based on the detection signal DET. Detects the moving operation of the pressurizing roller 44. Further, when the operating state of the fixing unit 40 is the nip state S1, the sensor control unit 99A detects the rotational operation of the pressurizing roller 44 based on the detection signal DET.

Further, the sensor control unit 99A also has a function of performing calibration for determining the amount of light emitted by the light emitting unit 72. Specifically, the sensor control unit 99A receives, for example, the amount of light reflected by the white portion (white light amount) and the amount of light reflected by the black portion of the color pattern PAT formed on the rotating plate 65 (described later). The amount of light emitted by the light emitting unit 72 is determined so that the difference from the amount of light (black light amount) is an appropriate amount. In the sensor control unit 99A, for example, the difference between the signal level L (signal level L1 described later) corresponding to the amount of white light and the signal level L (signal level L3 described later) corresponding to the amount of black light included in the detection signal DET is The amount of light emitted by the light emitting unit 72 is determined so as to be equal to or higher than a predetermined value. As a result, in the image forming apparatus 1, for example, it is possible to suppress the influence of variations in the characteristics of the light emitting unit 72 and changes in the amount of light due to aged deterioration.

(Fixing part 40)
6 to 8 show a configuration example of a main part of the fixing part 40. In FIGS. 6 to 8, the fixing belt 45 is not shown. FIG. 6 shows the fixing portion 40 viewed from the left side in FIGS. 1 and 3, and FIG. 8 shows the fixing portion 40 viewed from the upper side in FIGS. 1 and 3. The fixing portion 40 includes a power transmission portion 50, a cam shaft 55, two release cams 56 (release cams 56A and 56B), two roller levers 61 (roller levers 61A and 61B), a lever shaft 62, and a spring. It has 79, two rollers 63 (rollers 63A and 63B), a sensor shaft 64, and a rotating plate 65. FIG. 9 shows a configuration example of the power transmission unit 50. The power transmission unit 50 includes a drive gear 51, a fixing gear 52, a one-way gear 53, and a cam gear 54.

The drive gear 51 (FIGS. 6 and 9) is rotatable about a rotation shaft 151 and is configured to mesh with the fixing gear 52. Power is transmitted to the drive gear 51 from the fixing motor 96B (described later). The drive gear 51 transmits the power transmitted from the fixing motor 96B to the fixing gear 52. Further, the drive gear 51 can transmit the power transmitted from the fixing motor 96B to the one-way gear 53.

The fixing gear 52 is rotatable about a rotation shaft 141 and is configured to mesh with the drive gear 51. As shown in FIG. 6, the fixing gear 52 is provided at the end of the fixing roller 41 and is connected to the fixing roller 41. The fixing gear 52 is rotatably supported by the frame 100 together with the fixing roller 41. The fixing gear 52 rotates about the rotation shaft 141 based on the power transmitted from the drive gear 51. As a result, the fixing gear 52 can rotate the fixing roller 41 around the rotation shaft 141.

The one-way gear 53 is configured to be rotatable around a rotation shaft 153. The one-way gear 53 transmits the power to the cam gear 54 only when the power transmitted from the drive gear 51 is the power in one rotation direction. Specifically, the one-way gear 53 transmits the power transmitted from the drive gear 51 to the cam gear 54 when the fixing motor 96B performs a reverse rotation operation, and when the fixing motor 96B performs a forward rotation operation, The power transmitted from the drive gear 51 is not transmitted to the cam gear 54.

The cam gear 54 is configured to be rotatable around a rotation shaft 155. As shown in FIG. 6, the cam gear 54 is provided at the end of the cam shaft 55 and is connected to the cam shaft 55. The cam gear 54 is rotatably supported by the frame 100 together with the cam shaft 55. The cam gear 54 rotates about a rotation shaft 155 based on the power transmitted from the one-way gear 53. Since the one-way gear 53 transmits the power transmitted from the drive gear 51 to the cam gear 54 when the fixing motor 96B performs the reverse rotation operation, the cam gear 54 rotates when the fixing motor 96B performs the reverse rotation operation. .. As a result, the cam gear 54 can rotate the cam shaft 55 about the rotation shaft 155.

The camshaft 55 (FIGS. 6 to 8) is rotatable about a rotation shaft 155 and is rotatably supported by the frame 100. A cam gear 54 is connected to one end of the cam shaft 55. Further, release cams 56A and 56B are fixed to the camshaft 55. The camshaft 55 rotates about a rotation shaft 155 based on the power transmitted from the cam gear 54. As a result, the camshaft 55 rotates the release cams 56A and 56B about the rotation shaft 155.

The release cams 56A and 56B (FIGS. 6 to 8) are fixed to the camshaft 55 and are configured to rotate about the rotation shaft 155 by rotating the camshaft 55. The release cam 56A is fixed at a position corresponding to the roller lever 61A in the axial direction of the cam shaft 55, and the release cam 56B is fixed at a position corresponding to the roller lever 61B in the axial direction of the cam shaft 55. For example, as shown in FIGS. 7 and 8, the release cam 56A is arranged so as to face the lever portion 69 (described later) of the roller lever 61A. The release cam 56A rotates about the rotation shaft 155 to come into contact with the lever portion 69 of the roller lever 61A and apply stress to the roller lever 61A. The same applies to the release cam 56B.

The roller levers 61A and 61B (FIGS. 6 to 8) are configured to be rotatable around a lever shaft 62 (FIG. 7) within a predetermined angle range. The orientation of the roller levers 61A and 61B is determined by being urged by the spring 79 (FIG. 7). Further, the roller levers 61A and 61B are connected to each other and rotatably support the pressure roller 44 and the sensor shaft 64. As a result, the pressurizing roller 44 can rotate about the rotating shaft 144, and the sensor shaft 64 can rotate about the rotating shaft 163. As shown in FIG. 7, the roller lever 61A has an opening 68 and a lever portion 69. As shown in FIGS. 6 and 7, the fixing roller 41 penetrates the opening 68. As shown in FIGS. 7 and 8, the lever portion 69 of the roller lever 61A is arranged so as to face the release cam 56A. The same applies to the roller lever 61B. The release cams 56A and 56B rotate to come into contact with the lever portions 69 of the roller levers 61A and 61B, and stress is applied to the lever portions 69 so that the roller levers 61A and 61B rotate counterclockwise around the lever shaft 62. It rotates and tilts slightly to the left in FIG. 7.

The lever shaft 62 (FIG. 7) is configured to support the roller levers 61A and 61B and to be supported by the frame 100. As a result, the roller levers 61A and 61B are rotatably supported by the frame 100.

The spring 79 (FIG. 7) is configured to apply an urging force to the lever portions 69 of the roller levers 61A and 61B.

The rollers 63A and 63B (FIG. 6) are fixed to the sensor shaft 64, rotate about the rotation shaft 164, and are configured to come into contact with the surface of the pressure roller 44. Each of the rollers 63A and 63B is configured by using an elastic body such as rubber. The rollers 63A and 63B drive to rotate about the rotation shaft 164 in accordance with the rotation of the pressurizing roller 44. As a result, the rollers 63A and 63B rotate the sensor shaft 64 about the rotation shaft 164.

The sensor shaft 64 (FIGS. 6 and 7) is rotatable about a rotation shaft 164 and is rotatably supported by roller levers 61A and 61B. Rollers 63A and 63B are fixed to the sensor shaft 64. A rotating plate 65 is connected to one end of the sensor shaft 64. The sensor shaft 64 rotates about the rotation shaft 163 as the rollers 63A and 63B rotate. As a result, the sensor shaft 64 rotates the rotating plate 65 about the rotating shaft 164.

The rotating plate 65 (FIGS. 6 and 7) is connected to one end of the sensor shaft 64 and is configured to be rotatable around the rotating shaft 164. As shown in FIG. 6, the rotating plate 65 is arranged so as to face the sensor 70. A color pattern PAT is formed on the surface S of the rotating plate 65 facing the sensor 70.

FIG. 10 shows a configuration example of the color pattern PAT on the rotating plate 65. This color pattern PAT includes a region R1 arranged inside in the radial direction and a region R2 arranged outside in the radial direction. Region R2 includes regions R21 and R22 arranged side by side in the circumferential direction. In this example, the region R2 is divided into eight regions in the circumferential direction, and the regions R21 and the regions R22 are alternately arranged. In this example, region R1 is a white region, region R21 is a black region, and region R22 is a gray region.

In the fixing portion 40, as shown in FIG. 7, when the directions of the release cams 56A and 56B are maintained so as not to contact the lever portions 69 of the roller levers 61A and 61B, as shown in FIG. 4A, as shown in FIG. 4A. The operating state of the fixing portion 40 is the nip state S1. Then, when the fixing motor 96B performs a forward rotation operation, the fixing roller 41 rotates counterclockwise in FIG. 7, and the pressurizing roller 44 is driven clockwise in accordance with the rotation of the fixing roller 41. As a result, the rotating plate 65 rotates counterclockwise in response to the rotation of the pressurizing roller 44. In this case, the sensor 70 emits light to the region R21 or region R22 of the rotating plate 65. Then, the sensor 70 can detect the rotational operation of the pressurizing roller 44 based on the reflected light from the rotating plate 65.

Further, the fixing motor 96B transiently reversely rotates the release cams 56A and 56B so as to rotate the release cams 56A and 56B counterclockwise so that the release cams 56A and 56B apply stress to the lever portions 69 of the roller levers 61A and 61B. Then, the roller levers 61A and 61B are slightly tilted to the left with respect to the lever shaft 62. As a result, as shown in FIG. 4B, the operating state of the fixing unit 40 becomes the release state S2. At this time, since the position of the rotating plate 65 supported by the roller levers 61A and 61B moves, the relative position of the rotating plate 65 as seen from the sensor 70 changes. In this case, the sensor 70 emits light to the region R1 of the rotating plate 65. Then, the sensor 70 can detect the moving operation of the pressurizing roller 44 based on the reflected light from the rotating plate 65.

Here, the ID unit 20 corresponds to a specific example of the "image forming unit" in the present invention. The fixing portion 40 corresponds to a specific example of the "fixing portion" in the present invention. The pressure roller 44 corresponds to a specific example of the "first rotating member" in the present invention. The rotating plate 65 corresponds to a specific example of the "rotating body" in the present invention. The region R1 corresponds to a specific example of the "first region" in the present invention, the region R2 corresponds to a specific example of the "second region" in the present invention, and the region R3 corresponds to the "second region" in the present invention. Corresponds to a specific example of "third area". The rotating plate 65, the sensor shaft 64, and the rollers 63A and 63B correspond to a specific example of the "second rotating member" in the present invention. The sensor 70 corresponds to a specific example of the "sensor" in the present invention. The release cams 56A and 56B correspond to a specific example of the "movable member" in the present invention. The roller levers 61A and 61B correspond to a specific example of the "support member" in the present invention. The control unit 99 corresponds to a specific example of the "detection unit" in the present invention. The fixing roller 41 corresponds to a specific example of the "third rotating member" in the present invention. The fixing motor 96B corresponds to a specific example of the "motor" in the present invention.

[Operation and action]
Subsequently, the operation and operation of the image forming apparatus 1 of the present embodiment will be described.

(Overview of overall operation)
First, the overall operation outline of the image forming apparatus 1 will be described with reference to FIGS. 1, 2, and 5. When the communication unit 91 receives the print data DP from the host computer, the control unit 99 controls each block of the image forming apparatus 1 so that the image forming apparatus 1 starts the image forming operation. The transfer motor control unit 94A controls the operation of the transfer motor 94B, the drum motor control unit 95A controls the operation of the drum motor 95B, and the fixing motor control unit 96A controls the operation of the fixing motor 96B. The fixing motor 96B performs a forward rotation operation. The high-voltage power supply 93 includes a charging voltage applied to the charging roller 24 of the ID unit 20, a developing voltage applied to the developing roller 25 of the ID unit 20, a supply voltage applied to the supply roller 27 of the ID unit 20, and a transfer roller. Generates a transfer voltage applied to 19. The control unit 99 controls the exposure operation by the LED head 29 based on the print data DP. The heater control unit 97 controls the operation of the heater 42.

The recording medium 9 taken out from the medium storage unit 11 is conveyed toward the ID unit 20 along the transfer path 10. In the ID unit 20, an electrostatic latent image is formed on the surface of the photosensitive drum 21, and a toner image corresponding to the electrostatic latent image is formed (developed). The transfer roller 19 transfers the toner image formed on the photosensitive drum 21 onto the surface to be transferred of the recording medium 9. The operating state of the fixing unit 40 is set to the nip state S1, and the fixing unit 40 applies heat and pressure to the recording medium 9 on which the toner image is transferred. As a result, the toner on the recording medium 9 is heated, melted, and pressurized. In this way, the toner image is fixed on the recording medium 9. Then, the recording medium 9 is conveyed along the conveying path 10 and discharged to the stacker 34.

(Detailed operation)
Next, the operation of the fixing unit 40 will be described in detail.

11A and 11B show an operation example of the fixing unit 40, FIG. 11A shows a nip state S1, and FIG. 11B shows a release state S2.

For example, when the image forming apparatus 1 forms an image on the recording medium 9, in the fixing portion 40, as shown in FIG. 11A, the directions of the release cams 56A and 56B are set to the lever portions 69 of the roller levers 61A and 61B. Keep in a direction that does not touch. In this case, the spring 79 applies the urging force W1 to the lever portions 69 of the roller levers 61A and 61B to set the orientation of the roller levers 61A and 61B. As a result, the pressure contact portion N is formed between the fixing roller 41 and the pressure roller 44, and the operating state of the fixing portion 40 becomes the nip state S1.

Then, when the fixing motor 96B performs a forward rotation operation, the fixing roller 41 rotates counterclockwise in FIG. 11A. At this time, the release cams 56A and 56B do not rotate. That is, when the fixing motor 96B performs a forward rotation operation, the one-way gear 53 does not transmit the power transmitted from the drive gear 51 to the cam gear 54, so that the directions of the release cams 56A and 56B do not change. The pressurizing roller 44 rotates clockwise in response to the rotation of the fixing roller 41, and the rotating plate 65 rotates counterclockwise in response to the rotation of the pressurizing roller 44.

Then, for example, when the fixing motor 96B transiently reversely rotates after the image forming apparatus 1 forms an image on the recording medium 9, the release cams 56A and 56B rotate counterclockwise as shown in FIG. 11B. Rotating in the (rotational direction W2), the release cams 56A and 56B come into contact with the lever portions 69 of the roller levers 61A and 61B, and stress W3 is applied to the lever portions 69. As a result, as shown in FIG. 11B, the roller levers 61A and 61B rotate counterclockwise (rotational direction W4) around the lever shaft 62 and tilt slightly to the left. When the roller levers 61A and 61B are tilted in this way, the pressure roller 44 and the rotating plate 65 supported by the roller levers 61A and 61B move in a direction away from the fixing roller 41, so that the fixing roller 41 and the pressure roller The 44s are separated from each other, and the operating state of the fixing portion 40 is the release state S2.

In this way, the fixing portion 40 is set to the nip state S1 or the release state S2. The sensor 70 detects the operation of the fixing unit 40 by irradiating the rotating plate 65 of the fixing unit 40 with light and detecting the light reflected by the rotating plate 65.

12A and 12B show the relative positional relationship between the sensor 70 and the rotating plate 65, FIG. 12A shows the relative positional relationship in the nip state S1, and FIG. 12B shows the relative positional relationship in the release state S2. Shows the positional relationship.

As shown in FIG. 12A, when the operating state of the fixing portion 40 is the nip state S1, the sensor 70 faces the outer region R2 of the rotating plate 65. When the sensor 70 emits light, the sensor 70 detects the light reflected by the region R21 (black) in the region R2 or the light reflected by the region R22 (gray), and outputs a detection signal DET according to the detection result. Generate. Based on this detection signal DET, the sensor control unit 99A determines that the operating state of the fixing unit 40 is the nip state S1. In particular, when the rotating plate 65 is rotating, the sensor 70 alternately detects the light reflected by the region R21 (black) and the light reflected by the region R22 (gray). As a result, the sensor control unit 99A detects the rotational operation of the pressurizing roller 44 based on the detection signal DET.

Further, as shown in FIG. 12B, when the operating state of the fixing portion 40 is the release state S2, the sensor 70 faces the inner region R1 of the rotating plate 65. That is, in the release state S2, as shown in FIG. 11B, when the roller levers 61A and 61B are tilted, the pressure roller 44 and the rotary plate 65 supported by the roller levers 61A and 61B are separated from the fixing roller 41. As a result, the relative position of the rotating plate 65 as seen from the sensor 70 changes. As shown in FIG. 12B, the position of the rotating plate 65 in the release state S2 has moved to the right of the position of the rotating plate 65 in the nip state S1 (FIG. 12A), so that the sensor 70 Is opposed to the inner region R1 of the rotating plate 65. That is, the sensor 70 faces the region R2 in the rotating plate 65 in the nip state S1 and faces the region R1 in the rotating plate 65 in the release state S2. In the release state S2, when the sensor 70 emits light, the sensor 70 detects the light reflected by the region R1 (white) and generates a detection signal DET according to the detection result. The sensor control unit 99A detects the moving operation of the pressurizing roller 44 based on the detection signal DET.

13A and 13B show an example of the detection operation, in which FIG. 13A shows the waveform of the detection signal DET, and FIG. 13B shows the operation of the fixing motor 96B. The detection signal DET may have three signal levels L1 to L3. The signal level L1 is the signal level L of the detection signal DET when the light reflected by the region R1 (white) is detected, and the signal level L2 is the signal level L when the light reflected by the region R22 (gray) is detected. It is the signal level L of the detection signal DET, and the signal level L3 is the signal level L of the detection signal DET when the light reflected by the region R21 (black) is detected.

In this example, before the timing t1, the operating state of the fixing unit 40 is the release state S2. That is, at this time, as shown in FIG. 11B, the release cams 56A and 56B apply stress W3 to the lever portions 69 of the roller levers 61A and 61B, and the roller levers 61A and 61B are slightly tilted to the left. As shown in FIG. 12B, the sensor 70 faces the region R1 (white) in the rotating plate 65. Therefore, the signal level L of the detection signal DET is the signal level L1 (FIG. 13 (A)).

Then, at the timing t1, the fixing motor 96B starts the reverse rotation operation based on the instruction from the fixing motor control unit 96A (FIG. 13 (B)). As a result, the release cams 56A and 56B start to rotate in the rotation direction W2 (FIG. 11B).

Then, at the timing t2, when the release cams 56A and 56B are separated from the lever portions 69 of the roller levers 61A and 61B and the stress on the lever portions 69 of the roller levers 61A and 61B by the release cams 56A and 56B is eliminated, the spring 79 is attached. The force W1 (FIG. 11A) rotates the roller levers 61A and 61B, and the directions of the roller levers 61A and 61B are set as shown in FIG. 11A. As a result, the operating state of the fixing portion 40 becomes the nip state S1, and the sensor 70 faces the region R2 in the rotating plate 65 as shown in FIG. 12 (A). In this example, the sensor 70 faces the region R21 (black) in the region R2. Therefore, the signal level L of the detection signal DET becomes the signal level L3 (FIG. 13 (A)).

Then, at the timing t3, the fixing motor 96B stops the reverse rotation operation based on the instruction from the fixing motor control unit 96A (FIG. 13B). As a result, the release cams 56A and 56B stop rotating.

Next, at the timing t4, the fixing motor 96B starts a forward rotation operation based on an instruction from the fixing motor control unit 96A (FIG. 13B). As a result, the rotation period T starts. In the rotation period T, the fixing roller 41 rotates, the pressurizing roller 44 rotates in response to the rotation of the fixing roller 41, and the rotating plate 65 rotates in accordance with the rotation of the pressurizing roller 44. The sensor 70 alternately faces the region R21 (black) and the region R22 (gray). Therefore, the signal level L of the detection signal DET changes between the signal level L2 and the signal level L3 (FIG. 13 (A)).

Then, at the timing t5, the fixing motor 96B stops the forward rotation operation based on the instruction from the fixing motor control unit 96A (FIG. 13 (B)). As a result, the fixing roller 41, the pressurizing roller 44, and the rotating plate 65 stop rotating. In this way, the rotation period T ends. In this example, the rotation of the rotating plate 65 is stopped at a position where the sensor 70 faces the region R22 (gray) in the region R2. Therefore, the signal level L of the detection signal DET becomes the signal level L2 (FIG. 13 (A)).

Next, at the timing t6, the fixing motor 96B starts the reverse rotation operation based on the instruction from the fixing motor control unit 96A (FIG. 13 (B)). As a result, the release cams 56A and 56B start to rotate in the rotation direction W2 (FIG. 11B).

Then, at the timing t7, when the release cams 56A and 56B come into contact with the lever portions 69 of the roller levers 61A and 61B and the stress W3 (FIG. 11B) is applied to the lever portions 69 of the roller levers 61A and 61B, the roller lever 61A , 61B rotate in the rotation direction W4 (FIG. 11B), and the directions of the roller levers 61A and 61B are slightly tilted to the left. As a result, the operating state of the fixing portion 40 becomes the release state S2, and the sensor 70 faces the region R1 (white) in the rotating plate 65 as shown in FIG. 12 (B). Therefore, the signal level L of the detection signal DET becomes the signal level L1 (FIG. 13 (A)).

Then, at the timing t8, the fixing motor 96B stops the reverse rotation operation based on the instruction from the fixing motor control unit 96A (FIG. 13 (B)). As a result, the release cams 56A and 56B stop rotating.

As described above, in the image forming apparatus 1, the roller levers 61A and 61B for rotatably supporting the sensor shaft 64 and the pressurizing roller 44 connected to the rotating plate 65 are provided, and the rollers are provided according to the power of the release cams 56A and 56B. The levers 61A and 61B are rotated. Then, the rotating plate 65 is provided with the regions R1 and R2 juxtaposed in the radial direction, and the region R2 includes the regions R21 and R22 juxtaposed in the circumferential direction. As a result, one sensor 70 can detect the rotational operation and the moving operation of the pressure roller 44, so that the number of parts can be reduced.

(Comparison example)
Next, the operation of the present embodiment will be described in comparison with the comparative example. The fixing portion 40R of the image forming apparatus 1R according to the comparative example will be described below.

14 and 15 show a configuration example of a main part of the fixing part 40R. The fixing portion 40R has a rotating plate 57R and a rotating plate 65R.

The rotary plate 57R is connected to one end of the camshaft 55 and is configured to be rotatable around the rotary shaft 155. As shown in FIG. 15, a color pattern including white and black is formed on the rotating plate 57R. As shown in FIG. 14, the rotating plate 57R is arranged so as to face the sensor 79R. Similar to the sensor 70 according to the above embodiment, the sensor 79R is a reflection sensor in this example, and by irradiating the rotating plate 57R with light and detecting the light reflected by the rotating plate 57R, the fixing portion It is configured to detect whether the operating state of the 40R is the nip state S1 or the release state S2. That is, the sensor 79R can detect the moving operation of the pressurizing roller 44.

The rotary plate 65R is connected to one end of the sensor shaft 64 and is configured to be rotatable around the rotary shaft 164. As shown in FIG. 15, the rotating plate 65R is formed with a color pattern including white and black. The rotating plate 65R is divided into eight regions in the circumferential direction, and white regions and black regions are alternately arranged. As shown in FIG. 4, the rotating plate 65R is arranged so as to face the sensor 70R. Similar to the sensor 70 according to the above embodiment, the sensor 70R is a reflection sensor in this example, and pressurizes the rotating plate 65R by irradiating the rotating plate 65R with light and detecting the light reflected by the rotating plate 65R. It is configured to detect the rotational movement of the roller 44.

In the image forming apparatus 1R according to the comparative example, the sensor 79R detects the moving motion of the pressurizing roller 44, and the sensor 70R detects the rotational motion of the pressurizing roller 44. As described above, in the image forming apparatus 1R, the operation of the fixing unit 40R is detected by using the two sensors 79R and 70R. As a result, in the image forming apparatus 1R, the number of parts increases, so that, for example, the cost of parts increases, and it takes time and effort to manufacture the image forming apparatus 1R.

On the other hand, in the image forming apparatus 1 according to the present embodiment, one sensor 70 can detect the rotational operation and the moving operation of the pressurizing roller 44. As a result, the number of parts can be reduced in the image forming apparatus 1, so that, for example, the cost of parts can be reduced and the labor required to manufacture the image forming apparatus 1 can be reduced.

[effect]
As described above, in the present embodiment, the sensor shaft connected to the rotating plate and the roller lever that rotatably supports the pressurizing roller are provided, and the roller lever is rotated according to the power of the release cam. Then, the rotating plate is provided with the regions R1 and R2 juxtaposed in the radial direction, and the region R2 includes the regions R21 and R22 juxtaposed in the circumferential direction. As a result, one sensor can detect the rotational operation and the moving operation of the pressurizing roller, so that the number of parts can be reduced.

[Modification 1]
In the above embodiment, as shown in FIG. 10, the region R1 arranged inside in the radial direction of the rotating plate 65 is made into a white region, and is included in the region R2 arranged outside in the radial direction. Region R21 and region R22 are defined as a black region and a gray region, respectively, but are not limited thereto. For example, the area R1 arranged inside in the radial direction may be a gray area, and the area R21 and the area R22 included in the area R2 arranged outside in the radial direction may be a black area and a white area, respectively. .. Further, the region R1 arranged inside in the radial direction may be a black region, and the region R21 and the region R22 included in the region R2 arranged outside in the radial direction may be a white region and a gray region, respectively. ..

[Modification 2]
In the above embodiment, as shown in FIG. 10, one region R1 is arranged inside the rotating plate 65 in the radial direction, and two regions R21 and R22 are arranged outside in the radial direction. It is not limited to this. Alternatively, for example, one region may be arranged on the outer side in the radial direction and two regions may be arranged on the inner side in the radial direction. A modified example will be described in detail below.

FIG. 16 shows a configuration example of the color pattern PAT in the rotating plate 65A of the fixing portion 40A according to the present modification. This color pattern PAT includes a region Q1 arranged on the outside in the radial direction and a region Q2 arranged on the inside in the radial direction. Region Q2 includes regions Q21 and Q22 arranged side by side in the circumferential direction. In this example, region Q1 is a white region, region Q21 is a black region, and region Q22 is a gray region.

FIG. 17 shows the relative positional relationship between the sensor 70 and the rotating plate 65A, (A) shows the relative positional relationship in the nip state S1, and (B) shows the relative positional relationship in the release state S2. Shows the positional relationship.

As shown in FIG. 17A, when the operating state of the fixing portion 40A is the nip state S1, the sensor 70 faces the inner region Q2 of the rotating plate 65A. When the sensor 70 emits light, the sensor 70 detects the light reflected by the region Q21 (black) in the region Q2 or the light reflected by the region Q22 (gray), and outputs a detection signal DET according to the detection result. Generate. Based on this detection signal DET, the sensor control unit 99A determines that the operating state of the fixing unit 40A is the nip state S1. In particular, when the rotating plate 65A is rotating, the sensor 70 alternately detects the light reflected by the region Q21 (black) in the region Q2 and the light reflected by the region Q22 (gray). As a result, the sensor control unit 99A detects the rotational operation of the pressurizing roller 44 based on the detection signal DET.

Further, as shown in FIG. 17B, when the operating state of the fixing portion 40A is the release state S2, the sensor 70 faces the outer region Q1 of the rotating plate 65A. As shown in FIG. 17 (B), the position of the rotary plate 65A in the release state S2 has moved to the right of the position of the rotary plate 65 in the nip state S1 (FIG. 17 (A)), so that the sensor 70 Is opposed to the outer region Q1 of the rotating plate 65A. In the release state S2, when the sensor 70 emits light, the sensor 70 detects the light reflected by the region Q1 (white) and generates a detection signal DET according to the detection result. The sensor control unit 99A detects the moving operation of the pressurizing roller 44 based on the detection signal DET.

[Modification 3]
In the above embodiment, the frame 100 supports the fixing roller 41 and the roller levers 61A and 61B support the pressure roller 44, but the present invention is not limited to this. Instead, the frame 100 may support the pressurizing roller 44, and the roller levers 61A and 61B may support the fixing roller 41. Further, the sensor shaft 64 and the rotating plate 65 may be rotated according to the rotation of the fixing roller 41.

[Other variants]
Moreover, you may combine two or more of these modified examples.

Although the present technology has been described above with reference to embodiments and modifications, the present technology is not limited to these embodiments and the like, and various modifications are possible.

For example, in the above-described embodiment, the present technology is applied to a single-function printer, but the present technology is not limited to this, and instead, for example, a copy function, a fax function, a scan function, a print function, etc. It may be applied to a so-called Multi Function Peripheral (MFP) having the above.

For example, in the above-described embodiment, the present technology is applied to an image forming apparatus for forming a monochrome image, but the present invention is not limited to this, and instead, for example, an image forming apparatus for forming a color image. May be applied to.

For example, in the above-described embodiment and the like, as shown in FIG. 10, the color pattern PAT of the rotating plate 65 is configured by using black, white, and gray, but the color pattern PAT is not limited to this, and other colors are used. May be used. Further, for example, four or more colors may be used.

1 ... image forming apparatus, 11 ... medium storage unit, 12 ... medium sensor, 13 ... pickup roller, 14 ... hop sensor, 15A ... medium supply roller, 15B ... retard roller, 16A ... transfer roller, 16B ... pinch roller, 17A ... Registration roller, 17B ... Pinch roller, 18 ... Export sensor, 19 ... Transfer roller, 20 ... ID unit, 21 ... Photosensitive drum, 22 ... Cleaning member, 24 ... Charging roller, 25 ... Development roller, 26 ... Development blade, 27 ... Supply roller, 28 ... Toner accommodating part, 29 ... LED head, 31 ... Discharge sensor, 32A, 32B ... Discharge roller, 33A, 33B ... Discharge roller, 40 ... Fixing part, 41 ... Fixing roller, 42 ... Heater, 43 ... Temperature sensor, 44 ... Pressurized roller, 45 ... Fixing belt, 50 ... Power transmission unit, 51 ... Drive gear, 52 ... Fixing gear, 53 ... One-way gear, 54 ... Cam gear, 55 ... Cam shaft, 56A, 56B ... Release cam , 61A, 61B ... Roller lever, 62 ... Lever shaft, 63A, 63B ... Roller, 64 ... Sensor shaft, 65, 65A ... Rotating plate, 68 ... Opening, 69 ... Lever part, 70 ... Sensor, 71 ... Light amount control unit , 72 ... light emitting unit, 73 ... light receiving unit, 79 ... spring, 91 ... communication unit, 92 ... display operation unit, 93 ... high pressure power supply, 94A ... transfer motor control unit, 94B ... transfer motor, 95A ... drum motor control unit, 95B ... Drum motor, 96A ... Fixing motor control unit, 96B ... Fixing motor, 97 ... Heater control unit, 99 ... Control unit, 99A ... Sensor control unit, 100 ... Frame, 141, 144, 151, 153, 155, 164 ... Rotation axis, DET ... detection signal, N ... pressure welding part, Q1, R1, Q2, Q21, Q22, R21, R22 ... region, S1 ... nip state, S2 ... release state, T ... rotation period.

Claims (9)

An image forming unit that forms an image on a recording medium using a developing agent,
A fixing portion for fixing the developer to the recording medium is provided.
The fixing part is
A first rotating member that can move between the first position and the second position,
It has a first region and a second region of a first color that are rotated in accordance with the rotational movement of the first rotating member and are juxtaposed in the radial direction, and the second region is in the circumferential direction. A second rotating member having a rotating body including a first sub-region of a second color and a second sub-region of a third color arranged side by side,
A sensor that irradiates the rotating body with light and detects the light reflected by the rotating body.
Movable members and
An image forming apparatus that rotatably supports the first rotating member and the second rotating member, and also has a support member that can move based on the power of the movable member. A detection unit for detecting the operation of the first rotating member is further provided.
The sensor generates a first signal level based on the light reflected by the first region of the rotating body and is based on the light reflected by the first sub-region of the second region. A second signal level is generated and a third signal level is generated based on the light reflected by the second sub-region of the second region.
The detection unit
Based on the second signal level and the third signal level generated by the sensor, the rotational motion of the first rotating member is detected.
The image forming apparatus according to claim 1, wherein the moving motion of the first rotating member is detected based on whether or not the signal level generated by the sensor is the first signal level. The image forming apparatus according to claim 2, wherein the third signal level is a level between the first signal level and the second signal level. The image forming apparatus according to any one of claims 1 to 3, wherein the second region is provided outside the first region of the rotating body. The image forming apparatus according to any one of claims 1 to 3, wherein the second region is provided outside the first region of the rotating body. Further equipped with a third rotating member,
The first position is a position where the first rotating member is pressed toward the third rotating member.
The image forming apparatus according to any one of claims 1 to 5, wherein the second position is a position where the first rotating member is separated from the third rotating member. The image forming apparatus according to claim 6, further comprising a power transmission unit that transmits power to the movable member and the third rotating member. With more motors to generate power
The power transmission unit transmits the power generated by the motor to the movable member and the third rotating member.
The movable member is
It operates when the power generated by the motor is the power in the first rotation direction.
The image forming apparatus according to claim 7, wherein the motor stops when the power generated by the motor is power in the second rotation direction. A first rotating member that can move between the first position and the second position,
It has a first region and a second region of a first color that are rotated in accordance with the rotational movement of the first rotating member and are juxtaposed in the radial direction, and the second region is in the circumferential direction. A second rotating member having a rotating body including a first sub-region of a second color and a second sub-region of a third color arranged side by side,
Movable members and
A fixing device including a support member that rotatably supports the first rotating member and the second rotating member and is movable based on the power of the movable member.

Images