JP2011197459A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce friction generated between particles of a developer passing through between a developing roll 64 and a regulation member 66.SOLUTION: An imparting device 74 imparts ultrasonic vibrations to the regulation member 66 through a support member 72. Thus, separation and contact corresponding to an ultrasonic vibration cycle are caused between the respective particles of the developer G and between the particles of the developer G and the regulation member 66. Thus, the friction generated among the particles of the developer G passing through between the developing roll 64 (cylindrical member 70A) and the regulation member 66 and the friction generated between the developer G and the regulation member 66 are reduced.

Description

  The present invention relates to a developing device and an image forming apparatus.

  Patent Document 1 discloses a developing device shown below. In this developing device, the fiber brush 3 is bonded to the vibrator 4 and is arranged at a distance from the developing sleeve 1. The vibrator 4 is driven by a drive circuit 9, and an electric field is generated between the fiber brush 3 and the developing sleeve 1 by applying a bias voltage by a bias power source 10. The toner 8 that is disturbed by the fiber brush 3 and frictionally charged by the vibration of the vibrator 4 is electrostatically attracted by the electric field and is conveyed to the developing sleeve 1.

Japanese Patent Laid-Open No. 5-19614 (FIG. 1)

  An object of the present invention is to reduce friction generated between particles of a developer that passes between a conveying member that conveys the developer and a regulating member that contacts the developer and regulates the thickness of the developer layer. And

  According to the first aspect of the present invention, the developer is held on the outer periphery and rotated by itself so as to convey the developer toward the latent image, and opposed to the outer periphery of the carrier, and the carrier is conveyed. A regulating member that regulates the thickness of the developer layer formed on the transport body in contact with the developer, and mechanical ultrasonic vibration having an amplitude smaller than the particle diameter of the developer on the transport body. A developing device comprising: a held developer; and an applying unit that applies to at least one of the transport body and the regulating member.

  According to a second aspect of the present invention, there is provided an image holding member capable of holding an image, a charging device for charging the image holding member, and exposing the image holding member charged by the charging device to form an electrostatic latent image. An image forming apparatus comprising: an apparatus; and a developing device according to claim 1 that develops an electrostatic latent image formed on the image holding member by the exposure device.

  A third aspect of the present invention is the image forming apparatus according to the second aspect, further comprising a control unit that controls an amplitude of vibration applied by the applying unit in accordance with a conveying speed of the conveying member in each image forming mode.

  According to the configuration of the first aspect of the present invention, it is possible to reduce the friction generated between the particles of the developer passing between the conveyance body and the regulating member, as compared with the case where no applying means for applying vibration is provided. .

  According to the configuration of the second aspect of the present invention, image deterioration caused by frictional heat generated between the developer particles passing between the conveyance body and the regulating member, compared to a case where no applying means for applying vibration is provided. Can be suppressed.

  According to the configuration of the third aspect of the present invention, the developer particles passing between the transport body and the regulating member are not compared with the case where the control means for controlling the amplitude according to the transport speed of the transport body is not provided. The temperature rise due to the generated frictional heat can be managed.

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment. FIG. 2 is a schematic diagram illustrating the configuration of the developing device according to the present embodiment. FIG. 3 is a graph showing a relationship between a value obtained by multiplying the driving torque for driving the developing roll by the rotation speed of the developing roll and the developer temperature in the housing. FIG. 4 is a perspective view showing a portion where frictional heat is generated in the developing device according to the present embodiment. FIG. 5 is a graph showing the relationship between the driving torque for driving the developing roll and the amplitude of vibration applied by the applying device. FIG. 6 is a schematic diagram illustrating a configuration of the developing device according to the first modification. FIG. 7 is a perspective view showing a configuration of a vibrator in the developing device according to the first modification. FIG. 8 is a perspective view showing a configuration of wiring to the vibrator in the developing device according to the first modification. FIG. 9 is a perspective view showing a configuration of a modified example of the vibrator in the developing device according to the first modified example. FIG. 10 is a schematic diagram illustrating a configuration of a developing device according to a second modification.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

(Configuration of image forming apparatus according to the present embodiment)
First, the configuration of the image forming apparatus according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment. In addition, arrow UP shown in a figure shows the perpendicular direction upper direction.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 11 in which each component is housed.

  Inside the image forming apparatus main body 11, a recording medium accommodating unit 12 that accommodates a recording medium P such as paper, an image forming unit 14 that forms an image on the recording medium P, and the recording medium accommodating unit 12 to the image forming unit. 14, a transport unit 16 that transports the recording medium P to 14, and a control unit 20 that controls the operation of each unit of the image forming apparatus 10. In addition, a recording medium discharge unit 18 for discharging the recording medium P on which an image is formed by the image forming unit 14 is provided on the upper portion of the image forming apparatus main body 11.

  The image forming unit 14 includes image forming units 22Y, 22M, 22C, and 22K (hereinafter referred to as 22Y to 22K) that form toner images of colors of yellow (Y), magenta (M), cyan (C), and black (K). The intermediate transfer belt 24 as an example of a transfer body onto which the toner images formed by the image forming units 22Y to 22K are transferred, and the toner image formed by the image forming units 22Y to 22K to the intermediate transfer belt 24. A first transfer roll 26 as an example of a first transfer member to be transferred, and a second transfer member for transferring the toner image transferred to the intermediate transfer belt 24 by the first transfer roll 26 from the intermediate transfer belt 24 to the recording medium P. And a second transfer roll 28 as an example.

  The image forming units 22 </ b> Y to 22 </ b> K are arranged side by side at the center in the vertical direction of the image forming apparatus 10 along the horizontal direction. Each of the image forming units 22Y to 22K includes a photoreceptor 32 that rotates in one direction (a clockwise direction in FIG. 1) as an example of an image holder that holds an image.

  Around each photoconductor 32, a charging roll 34 as an example of a charging device that charges the photoconductor 32 and a photoconductor 32 charged by the charge roll 34 are exposed in order from the upstream side in the rotation direction of the photoconductor 32. A developing device 60 that develops the formed electrostatic latent image to form a toner image, and toner remaining on the photoconductor 32 after the toner image formed on the photoconductor 32 is transferred to the intermediate transfer belt 24. And a removing device 40 for removing.

  Further, below the image forming units 22 </ b> Y to 22 </ b> K, an exposure device 36 that exposes each photosensitive member 32 charged by the charging roll 34 to form an electrostatic latent image is provided. The exposure device 36 is configured to form an electrostatic latent image based on the image signal sent from the control unit 20. Examples of the image signal sent from the control unit 20 include an image signal acquired by the control unit 20 from an external device.

  The intermediate transfer belt 24 is formed in an annular shape and is disposed on the upper side of the image forming units 22Y to 22K. Winding rolls 42 and 44 around which the intermediate transfer belt 24 is wound are provided on the inner peripheral side of the intermediate transfer belt 24. The intermediate transfer belt 24 circulates (rotates) in one direction (counterclockwise direction in FIG. 1) while being in contact with the photosensitive member 32 when one of the winding rolls 42 and 44 is rotationally driven. ing. The winding roll 42 is an opposing roll that faces the second transfer roll 28.

  The first transfer roll 26 faces the photoconductor 32 with the intermediate transfer belt 24 interposed therebetween. A space between the first transfer roll 26 and the photoconductor 32 is a first transfer position where the toner image formed on the photoconductor 32 is transferred to the intermediate transfer belt 24.

  The second transfer roll 28 faces the winding roll 42 with the intermediate transfer belt 24 interposed therebetween. A space between the second transfer roll 28 and the winding roll 42 is a second transfer position where the toner image transferred to the intermediate transfer belt 24 is transferred to the recording medium P.

  The transport unit 16 is disposed along the transport path 48, a feed roll 46 that feeds the recording medium P accommodated in the recording medium container 12, a transport path 48 that transports the recording medium P sent to the transport roll 46, and the transport path 48. A plurality of transport rolls 50 are provided for transporting the recording medium P delivered by the delivery roll 46 to the second transfer position.

  A fixing device 30 for fixing the toner image transferred from the intermediate transfer belt 24 to the recording medium P by the second transfer roller 28 at the second transfer position on the recording medium P is provided downstream of the second transfer position in the transport direction. ing. A discharge roll 52 that discharges the recording medium P on which the toner image is fixed to the recording medium discharge unit 18 is provided downstream of the fixing device 30 in the transport direction.

  Next, an image forming operation for forming an image on the recording medium P in the image forming apparatus 10 according to the present embodiment will be described.

  In the image forming apparatus 10 according to the present embodiment, the recording medium P sent out from the recording medium container 12 by the sending roll 46 is sent to the second transfer position by the plurality of transport rolls 50.

  On the other hand, in the image forming units 22 </ b> Y to 22 </ b> K, the photosensitive member 32 charged by the charging roll 34 is exposed by the exposure device 36 to form an electrostatic latent image on the photosensitive member 32. The electrostatic latent image is developed by the developing device 60 to form a toner image on the photoreceptor 32. The color toner images formed by the image forming units 22Y to 22K are superimposed on the intermediate transfer belt 24 at the first transfer position to form a color image. Then, the color image formed on the intermediate transfer belt 24 is transferred to the recording medium P at the second transfer position.

  The recording medium P to which the toner image has been transferred is conveyed to the fixing device 30, and the transferred toner image is fixed by the fixing device 30. The recording medium P on which the toner image is fixed is discharged to the recording medium discharge unit 18 by the discharge roll 52. As described above, a series of image forming operations are performed.

(Configuration of developing device 60)
Next, the configuration of the developing device 60 will be described. FIG. 2 is a schematic diagram showing the configuration of the developing device 60.

  The developing device 60 includes a housing 62 as an example of a storage unit in which the developer G is stored, and a transport body that is provided inside the housing 62 and transports the developer G toward the electrostatic latent image of the photoconductor 32. As an example, the developing roller 64, a regulating member 66 that regulates the thickness of the developer layer formed on the developing roller 64, and conveying members 67A and 67B that convey the developer G applied to the developing roller 64 while stirring. And. The developer G includes, for example, a nonmagnetic toner and a magnetic carrier.

  The conveying members 67A and 67B include, for example, a rotatable rotating shaft 68A and a blade member 68B provided on the rotating shaft 68A in a spiral shape around the shaft. When the rotation shaft 68A of the transport member 67A rotates, the blade member 68B transports the developer G to one side of the rotation shaft 68A while stirring the developer G, and the rotation shaft 68A of the transport member 67B rotates to rotate the blade While stirring the developer G, the member 68B transports the developer G along the axial direction of the rotation shaft 68A in the direction opposite to the transport direction of the transport member 67A.

  The developing roll 64 is a cylindrical member 70 </ b> A that is rotatably supported with respect to the casing 62, and a columnar magnetic member 70 </ b> B that is provided inside the cylindrical member 70 </ b> A and is fixed to the casing 62. It is equipped with.

  The cylindrical member 70 </ b> A is exposed from the housing 62 to the photoconductor 32 side and faces the photoconductor 32. To the outer periphery of the cylindrical member 70A, the developer G conveyed by the conveying member 67B disposed on the side close to the cylindrical member 70A (developing roll 64) is applied by the magnetic force of the magnetic member 70B. .

  In the developing roll 64, the developer G applied from the conveying member 67B is held on the outer periphery of the cylindrical member 70A by the magnetic force of the magnetic member 70B, and the cylindrical member 70A rotates to face the photosensitive member 32. The developer G is conveyed toward the head. The developer G transported to a position facing the photoconductor 32 is supplied to the photoconductor 32 by electrostatic force or the like.

  The regulating member 66 is disposed at a position facing the cylindrical member 70A between the photosensitive member 32 and the conveying member 67B, contacts the developer G held and conveyed by the cylindrical member 70A, and the cylindrical member 70A. The thickness of the developer layer formed is regulated. In this way, the regulating member 66 regulates the thickness of the developer layer, so that when the developer G held by the cylindrical member 70A passes between the cylindrical member 70A and the regulating member 66, the developer G Friction occurs between the particles, and friction occurs between the developer G held on the cylindrical member 70 </ b> A and the regulating member 66.

  Further, the regulating member 66 is supported by a support member 72 fixed to the housing 62.

  Here, in this embodiment, the application as an example of an application unit that applies dynamic ultrasonic vibration having a smaller amplitude than the particle diameter of the developer G (specifically, the particle diameter of the toner) to the regulating member 66. A device 74 is provided for the support member 72.

  The applying device 74 includes a vibrator 76 that includes a piezoelectric element and generates ultrasonic vibrations, and an amplification horn 78 that is an example of an amplifier that amplifies the amplitude of ultrasonic vibrations generated by the vibrator 76 and transmits the amplified amplitude to the regulating member 66. , And is configured.

  An application unit 79 that applies a voltage to the piezoelectric element is electrically connected to an electrode (not shown) provided on the surface of the piezoelectric element. The vibrator 76 is configured to generate a vibration having an amplitude corresponding to the voltage applied from the applying unit 79 and to generate a vibration having a frequency corresponding to the frequency of the voltage applied from the applying unit 79. The applying device 74 is configured to apply vibration to the restricting member 66 via the support member 72, but may be configured to apply vibration directly to the restricting member 66.

  The ultrasonic vibration is vibration that becomes a sound wave (elastic wave) having a frequency (frequency) high enough not to cause hearing sensation in a person with normal hearing ability, and specifically, vibration of 20 kHz or more. Say. The mechanical vibration means mechanical vibration that is not electrical vibration.

  The application unit 79 is connected to a control unit 77 as an example of a control unit that controls the amplitude of vibration applied by the applying device 74 to the regulating member 66. The control unit 77 controls the voltage applied by the applying unit 79 to the piezoelectric element of the vibrator 76, so that the amplitude in accordance with the transport speed for transporting the developer G of the developing roll 64 to the photoconductor 32 in each image forming mode. It is the structure which controls. Specifically, the control unit 77 controls the amplitude according to the rotation speed (rotation speed) of the developing roll 64.

  In the present embodiment, the image forming mode includes, for example, a mode corresponding to the image quality and the type / thickness of the recording medium P, and the image forming speed (process speed) including the number of rotations of the developing roll 64 is set according to the mode. It is going to change. For example, in the high image quality mode for forming an image with higher image quality than in the standard image quality mode, the number of rotations of the developing roller 64 is smaller than in the standard image quality mode, and in the thick paper mode for forming an image on a thick paper thicker than plain paper, The number of rotations is smaller than that in the plain paper mode for image formation.

  As shown in FIG. 3, the value obtained by multiplying the drive torque for the drive motor 67 (see FIG. 4) to drive the developing roll 64 by the rotation speed of the developing roll 64 is proportional to the developer temperature in the housing 62. There is a relationship. Accordingly, when at least one of the rotation speed of the developing roll 64 and the value of the driving torque of the developing roll 64 is increased, the developer temperature in the housing 62 is increased.

  This is because the frictional heat H2 between the particles of the developer G passing between the developing roll 64 (cylindrical member 70A) and the regulating member 66 increases when the rotational speed of the developing roll 64 increases. Further, when the driving torque in the developing roll 64 increases, the frictional heat H1 in the gear 65 provided on the developing roll 64 (cylindrical member 70A) increases, and the heat is conducted to the developer G in the housing 62. It is.

  Here, when ultrasonic vibration is applied by the applying device 74, friction between the particles of the developer G and between the developer G and the regulating member 66 is reduced (Journal of Powder Technology Society Vol.46, No.5, pp.330-337 (2009) "Effects of particle properties on particle friction reduction by ultrasound"). This is because the ultrasonic vibration causes separation and contact between the particles of the developer G and between the developer G and the regulating member 66 in accordance with the vibration period, thereby reducing the frictional resistance acting on the unit time. It is believed that there is. Further, if the amplitude of the ultrasonic vibration is increased, it is considered that the separation time becomes longer, and the friction reducing effect is enhanced. When this friction is reduced, the rotational resistance of the developing roll 64 is reduced and the driving torque is reduced. Therefore, as shown in FIG. 5, the driving torque in the developing roll 64 is proportional to the amplitude of the ultrasonic vibration applied to the regulating member 66 by the applying device 74.

  From the above, the drive torque for preventing the developer temperature from exceeding the desired upper limit temperature is defined from the desired upper limit temperature of the developer temperature and the rotation speed of the developing roller 64 in each image forming mode (see FIG. 3), the amplitude of the ultrasonic vibration is defined from this driving torque (see FIG. 5). The desired upper limit temperature of the developer temperature is set, for example, by the temperature at which the developer G (toner) melts.

  Therefore, in the present embodiment, the control unit 77 presets the amplitude of ultrasonic vibrations according to the rotation speed (rotation speed) of the developing roll 64 in each image forming mode to form a table, and the control unit 77 receives an input. The application unit 79 is controlled so that a voltage corresponding to the amplitude is applied with reference to the amplitude corresponding to the image forming mode.

  The control unit 77 may be configured to determine the amplitude of the ultrasonic vibration without referring to the table as in the following procedure. When the controller 77 first acquires the rotation speed of the developing roll 64 in each image forming mode, the controller 77 determines the rotation speed of the developing roll 64 and the developing roll 64 in which a preset developer temperature is determined from a desired upper limit temperature. An allowable torque is obtained (see FIG. 3). Next, the control unit 77 obtains an amplitude determined from the allowable torque (see FIG. 5), and the control unit 77 controls the application unit 79 so that a voltage corresponding to the amplitude is applied.

  Further, the amplitude of the vibration applied to the regulating member 66 is at least smaller than the thickness of the developer layer formed by being regulated by the regulating member 66 and further smaller than the particle diameter of the particles constituting the developer G. It has become. For example, when the developer G is composed of toner and carrier, the amplitude is smaller than that of any particle of toner and carrier.

  Specifically, for example, the developer layer thickness is 10 to 20 μm, the toner particle diameter is 5 μm, and the amplitude is set to 0.2 μm, which is 1/10 or less of the toner particle diameter.

  The control unit 77 may be configured by the control unit 20 (see FIG. 1) that controls the operation of each unit of the image forming apparatus 10, or may be configured separately from the control unit 20. .

(Operation of this embodiment)
Next, the operation of this embodiment will be described.

  The developer G supplied from the conveying member 67B to the cylindrical member 70A of the developing roll 64 is held on the outer periphery of the cylindrical member 70A by the magnetic force of the magnetic member 70B, and is opposed to the photoconductor 32 by rotating the cylindrical member 70A. It is conveyed toward the facing position.

  While being held by the cylindrical member 70A, the regulating member 66 comes into contact with the developer G conveyed to the opposite position, and the thickness of the developer layer formed on the cylindrical member 70A is regulated.

  In the present embodiment, the applying device 74 applies ultrasonic vibration to the regulating member 66 through the support member 72. Thereby, it is considered that separation and contact according to the ultrasonic vibration period occur between the particles of the developer G and between the particles of the developer G and the regulating member 66, and the regulation with the developing roll 64 (cylindrical member 70 </ b> A). The friction generated between the particles of the developer G passing between the member 66 and the friction generated between the developer G and the regulating member 66 is reduced. Thereby, the passage resistance when the developer G held on the developing roll 64 passes between the developing roll 64 and the regulating member 66, that is, the rotational resistance of the developing roll 64 is reduced, and the developing roll 64 is driven to rotate. An increase in driving torque during the operation is suppressed.

  By reducing the friction generated between the particles of the developer G passing between the developing roll 64 and the regulating member 66, the frictional heat H2 (see FIG. 4) due to the friction is reduced, and the temperature of the developer G is increased. Is suppressed. Further, by suppressing an increase in the driving torque of the developing roll 64, the frictional heat at the gear 65 of the developing roll 64 is reduced, and the temperature rise of the developer G is suppressed. Thereby, image deterioration due to deterioration such as melting occurring in the developer G is suppressed.

  Note that it is considered that the frictional heat in the gear of the developing roll 64 is conducted to the developer G through the housing 62 and the like, so that the temperature of the developer G rises.

  In this embodiment, the control unit 77 controls the amplitude of vibration applied to the regulating member 66 by the applying device 74 in accordance with the number of rotations (rotational speed) of the developing roll 64 in each image forming mode. Well, the temperature rise of the developer G is managed. As a result, no vibration is applied to the regulating member 66 unnecessarily, leading to energy saving.

  In addition, the control of the amplitude by the control unit 77 causes the developer G to be charged due to friction within a range in which deterioration due to frictional heat does not occur, so that static electricity for satisfactorily supplying the developer G to the photoreceptor 32 can be obtained. Since electric power is obtained, it is possible to achieve both the image quality maintenance and the temperature increase of the developer G.

  In the present embodiment, the shape and material of the regulating member 66 itself that contacts the developer G are not changed, but friction is reduced by the vibration of the regulating member 66, so that the regulating member 66 contacts the developer G. Compared to a configuration in which the contact area is reduced by changing the shape of the surface, or a configuration in which a material having a small friction coefficient is interposed between the regulating member 66 and the developer G to reduce friction, the developer layer is formed. Hard to influence.

  Further, in this embodiment, the generated heat is not released, but the generation of frictional heat as a heat source is suppressed, so that heat is released compared to the configuration in which the temperature rise of the developer G is suppressed by air cooling. Therefore, it is not necessary to secure a route or the like, saving space and reducing the size of the apparatus.

  Further, since the amplitude of the ultrasonic vibration is smaller than the particle diameter of the particles constituting the developer layer and the developer G formed by being regulated by the regulating member 66, the uniformity of the layer thickness of the developer layer is affected. Hard to give.

  The applying device is not limited to the above-described applying device 74, and may be, for example, the one shown in the following modification, and mechanical ultrasonic vibration having an amplitude smaller than the particle diameter of the developer G, Any material may be used as long as it is applied to at least one of the developer G, the developing roller 64, and the regulating member 66 held by the developing roller 64.

(Granting device according to first modification)
Next, an applicator according to a first modification will be described.

  As shown in FIG. 6, the applying device 80 according to the first modification is configured as an example of an applying unit that applies a dynamic ultrasonic vibration having an amplitude smaller than the particle diameter of the developer G to the developing roll 64. Yes. Specifically, in the applying device 80, a vibrator 82 that includes a piezoelectric element and generates ultrasonic vibration is fixed to the inner periphery of the cylindrical member 70A.

  As shown in FIG. 7, the vibrator 82 has a cylindrical shape in which a gap S is formed from one end to the other end in the axial direction in a part of the circumferential direction.

  The shaft portions 70 </ b> C provided at both axial ends of the magnetic member 70 </ b> B of the developing roll 64 are supported by the bearings 84 and are fixed to the housing 62 of the developing device 60.

  The bearing 84 is fixed with respect to the cylindrical member 70A, and the cylindrical member 70A and the vibrator 82 rotate together as the bearing 84 rotates.

  As shown in FIG. 6, the vibrator 82 has an application unit 83 for applying a voltage to the piezoelectric element, electrically connected to an electrode (not shown) provided on the surface of the piezoelectric element via a wiring 81. It is connected.

  As shown in FIG. 8, the wiring 81 is one end in the axial direction of the vibrator 82, and includes electric wires 86 </ b> A and 86 </ b> B each having one end connected to one end and the other end in the circumferential direction with the gap S therebetween. I have. The other ends of the electric wires 86A and 86B are respectively connected to annular connection terminals 88A and 88B provided on the outer periphery of the bearing 84 along the circumferential direction.

  Each of the connection terminals 88A and 88B is provided with connection terminals 89A and 89B pressed against the connection terminals 88A and 88B by an elastic force or the like. Since the connection terminals 89A and 89B move relatively while sliding on the connection terminals 88A and 88B even when the bearing 84 rotates, the contact state with respect to the connection terminals 88A and 88B is maintained.

  When a voltage is applied from the application unit 83 connected to the connection terminals 89A and 89B to the piezoelectric element of the vibrator 82 through the connection terminals 89A and 89B and the electric wires 86A and 86B, the vibrator 82 moves in the radial direction of the cylindrical member 70A. It is deformed to generate vibration. The vibrator 82 is configured to generate a vibration having an amplitude corresponding to the voltage applied from the applying unit 83 and to generate a vibration having a frequency corresponding to the frequency of the voltage applied from the applying unit 83. As shown in FIG. 6, the control unit 77 is connected to the application unit 83 and is controlled in the same manner as in the applying device 74.

  As shown in FIG. 9, the configuration that causes the developing roll 64 to vibrate is a configuration in which vibrators 82 that include a piezoelectric element and generate ultrasonic vibration are arranged at both ends in the axial direction of the cylindrical member 70A. May be. In the configuration shown in FIG. 9, the vibrator 82 is rotatably attached to the shaft portion 70 </ b> C, and is fixed to the cylindrical member 70 </ b> A and the bearing 84 between the axial end portion of the cylindrical member 70 </ b> A and the bearing 84. .

(Granting device according to second modification)
Next, an applicator according to a second modification will be described.

  As shown in FIG. 10, the applying device 90 according to the second modification applies dynamic ultrasonic vibration having an amplitude smaller than the particle diameter of the developer G to the developer G held on the developing roll 64. It is comprised as an example of the provision means.

  The applying device 90 according to the second modification is an example of a vibrator 92 that includes a piezoelectric element and generates ultrasonic vibration, and an amplifier that amplifies the amplitude of the ultrasonic vibration generated by the vibrator 92 and transmits the amplified amplitude to the developer G. And a sound guide duct 94.

  Specifically, the sound guide duct 94 has a vibration amplified by resonating in the duct in the vicinity between the developing roll 64 and the regulating member 66 and between the developing roll 64 and the regulating member 66. Also, the developer G existing on the upstream side in the transport direction is irradiated. Thereby, the developer G that contacts the developing roll 64 and the developer G that contacts the regulating member 66 vibrate.

  In the vibrator 92, an application unit 96 that applies a voltage to the piezoelectric element is electrically connected to an electrode (not shown) provided on the surface of the piezoelectric element. The vibrator 92 is configured to generate a vibration having an amplitude corresponding to the voltage applied from the applying unit 96 and to generate a vibration having a frequency corresponding to the frequency of the voltage applied from the applying unit 96. The control unit 77 is connected to the application unit 96 and is similarly controlled.

  Note that the applying means for applying dynamic ultrasonic vibration to the developer G held on the developing roll 64 is configured to irradiate the developer G existing between the developing roll 64 and the regulating member 66 with vibration. There may be a configuration in which vibration is applied to the developer G present on the downstream side in the transport direction from between the developing roll 64 and the regulating member 66.

  Further, in the present embodiment, the amplitude of vibration applied by the applying devices 74, 80, and 90 is controlled. However, even if the amplitude is not controlled, ultrasonic vibration with a predetermined amplitude is applied. Good. In addition, the developing device may have a plurality of any of the applying devices 74, 80, and 90.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

10 Image Forming Device 32 Photoconductor (Example of Image Holding Body)
34 Charging roll (an example of a charging device)
36 exposure device 60 developing device 64 developing roll (an example of a conveying member)
66 restricting member 74 applying device (an example of applying means)
77 Control unit (an example of control means)
80 Application device (an example of an application unit)
90 Application device (an example of an application unit)

Claims (3)

A carrier that holds the developer on the outer periphery and rotates by itself to convey the developer toward the latent image;
A regulating member that faces the outer periphery of the transport body, contacts the developer transported by the transport body, and regulates the thickness of the developer layer formed on the transport body;
Applying means for applying dynamic ultrasonic vibration having an amplitude smaller than the particle diameter of the developer to at least one of the developer held on the transport body, the transport body, and the regulating member;
A developing device comprising: An image carrier capable of holding an image;
A charging device for charging the image carrier;
An exposure device that exposes the image carrier charged by the charging device to form an electrostatic latent image; and
The developing device according to claim 1, wherein the electrostatic latent image formed on the image carrier is developed by the exposure device;
An image forming apparatus comprising:   The image forming apparatus according to claim 2, further comprising a control unit that controls an amplitude of vibration applied by the applying unit according to a conveying speed of the conveying member in each image forming mode.

Images