JP5757912B2 - Developing device and image forming apparatus including the same - Google Patents

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof, and an image forming apparatus including the developing device.

  Conventionally, in an image forming apparatus, toner is supplied from a developing device onto an image carrier on which an electrostatic latent image is formed, and the electrostatic latent image is developed into a toner image. In some color image forming apparatuses, a developing device is provided so as to be able to contact and separate from an image carrier such as a photosensitive drum or a photosensitive belt. For example, the developing device described in Patent Document 1 includes a developing roller that supplies toner to the photosensitive belt, a toner supply roller that supplies toner to the developing roller, and an agitator that stirs the toner. The developing container that supports the developing roller, the agitator, and the like is provided with a sliding member that slides in the vertical direction with respect to the main body of the apparatus so that the developing apparatus can contact and separate from the photosensitive belt in the vertical direction. ing. The center of gravity of the developing device is set lower than the center of the developing container, and the sliding member is positioned lower than the center of gravity of the developing device. When the developing device moves up and down, the developing roller, the agitator, etc. rotate. Thus, when developing, it is difficult to generate vibrations that rotate about the sliding member, and image disturbance during development is prevented.

  The image forming apparatus described in Patent Document 2 is configured by combining a developing container that is integrated with a toner supply container and rotatably holds a developing roller, and a cleaning container that rotatably holds an image carrier. The In order to hold the image carrier and the developing roller at a predetermined interval and connect the developing container and the cleaning container, a tension spring is stretched between the developing container and the cleaning container, and both containers are Is pressurized. Then, the arm portion extends horizontally from the upper surface of the cleaning container toward the developing container side, a rib is provided on the upper surface of the developing container, and the rib and the arm portion are rotatably coupled to the upper surface of the developing container. Has been. With this configuration, the rotation center of the developing container with respect to the cleaning container is located on a perpendicular line passing through the center of gravity of the developing container, so that the moment around the rotation center is 0 (zero), and both containers are added in the initial stage of use when the amount of toner is large. The state in which the pressure is excessive is eliminated, the spacer member is not deformed by excessive pressure, and the occurrence of image disturbance is prevented.

JP-A-9-197826 (paragraphs [0039] to [0042], FIG. 2) JP-A-7-146634 (paragraphs [0019] to [0025], FIG. 1)

  However, since the developing device described in Patent Document 1 has a configuration in which the center of gravity of the developing device is lower than the center of the developing container, the layout of the device is limited and it is difficult to reduce the size of the device. Further, in the configuration in which the center of gravity of the developing device is located lower than the center of the developing container, when the agitator and the developing roller are rotated by rotating the driving gear connected to the driving source, it is possible to remove the vibration of the developing device. It was still insufficient.

  Further, the image forming apparatus described in Patent Document 2 has a problem that it is difficult to remove vibration of the developing device when the developing roller is rotated by rotating a driving gear or the like connected to a driving source.

  The present invention has been made to solve the above-described problems, and a developing device that suppresses vibrations of the developing device due to rotation when the developing roller and the stirring member are driven to rotate, and an image forming apparatus including the developing device. The purpose is to provide.

  In order to achieve the above object, a first invention provides a developing container for containing toner, an agitating member for agitating and conveying the toner in the developing container, and supplying the toner conveyed from the agitating member to the image carrier. A developing roller, and a driving shaft that transmits a rotational force from a driving source to the stirring member and the developing roller, and an inertia main shaft that passes through the center of gravity of the developing device and extends in a longitudinal direction of the developing device. It is characterized by being configured to be located within the shaft diameter of the drive shaft.

  According to a second aspect of the present invention, in the developing device, a balancing member having a predetermined mass for positioning the inertia main shaft within the shaft diameter of the drive shaft is provided.

  According to a third aspect of the present invention, there is provided a developing container for containing toner, a stirring member for stirring and transporting the toner in the developing container, and supplying the toner transported from the stirring member to the image carrier. A detachable developing device having a developing roller, a driving shaft for transmitting a rotational force from a driving source to the stirring member and the developing roller, and a balancing member having a predetermined mass and movable in the vertical direction. When the developing device is mounted, the balancing member is held at a predetermined position of the developing device, and an inertia main shaft that extends in the longitudinal direction of the developing device passes through the center of gravity of the developing device. It is located within the shaft diameter of the drive shaft.

  According to a fourth aspect of the present invention, there is provided a developing container for containing toner, a stirring member for stirring and transporting the toner in the developing container, and supplying the toner transported from the stirring member to the image carrier. A developing roller, a driving shaft for transmitting a rotational force from a driving source to the stirring member and the developing roller, a toner replenishing container that is detachable from the developing container and stores toner to be replenished in the developing container; A developing device having a predetermined mass that is movable in the vertical direction; a driving unit that moves the balancing member in the vertical direction; and a toner supply container that is filled with toner. Print counting means for accumulating the total printing time or the total number of printed sheets, and driving the driving means on the basis of the total printing time or the total number of printed sheets of the print counting means, Principal axis of inertia extending in the longitudinal direction of the street the developing device is a and a control means for controlling so as to be positioned in the axial diameter of the said drive shaft.

  According to a fifth aspect of the present invention, there is provided a developing container for storing toner, a stirring member for stirring and transporting the toner in the developing container, and supplying the toner transported from the stirring member to the image carrier. A developing roller, a driving shaft for transmitting a rotational force from a driving source to the agitating member and the developing roller, a toner replenishing container for storing toner to be replenished to the developing container, and a vertically movable having a predetermined mass. And a developing device having a horizontally swingable balancing member, a driving means for moving the balancing member in the vertical direction and swinging horizontally around the lower end, and a predetermined position of the developing device A plurality of weight sensors disposed on the developing device and measuring a weight position of the developing device based on outputs of the plurality of weight sensors; The is driven, longitudinally extending principal axis of inertia of the center of gravity as the developing device of the developing device is characterized by comprising a control means for controlling so as to be positioned in the axial diameter of the said drive shaft.

  According to the first aspect of the present invention, the inertia main shaft that passes through the center of gravity of the developing device and extends in the longitudinal direction of the developing device is positioned within the shaft diameter of the driving shaft, thereby driving the stirring member and the developing roller to rotate. The shaft rotates stably, and the rotational moment that tries to vibrate the developing device is suppressed.

Sectional drawing which shows schematically an image forming apparatus provided with the developing device which concerns on embodiment of this invention Sectional drawing which shows schematically the image development apparatus concerning 1st Embodiment of this invention. 1 is a side view schematically showing the arrangement of drive shafts of a developing device according to a first embodiment. A side view schematically showing a developing device provided with a balancing member according to a second embodiment. FIG. 6 is a side view schematically illustrating a developing device that holds a balancing member of an image forming apparatus according to a third embodiment. FIG. 6 is a side view schematically illustrating an image forming apparatus that moves a balancing member according to the amount of toner in a toner supply container according to a fourth embodiment. The top view which shows roughly the developing device provided with the weight sensor which concerns on 5th Embodiment FIG. 9 is a side view schematically illustrating an image forming apparatus that operates a balancing member according to the weight of a toner supply container according to a fifth embodiment.

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

(First embodiment)
FIG. 1 is a cross-sectional view of a schematic configuration of an image forming apparatus provided with a developing device according to the present invention. The image forming apparatus 1 includes a sheet feeding unit 2 disposed in a lower portion thereof, a sheet conveying unit 3 disposed on the right side of the sheet feeding unit 2, and an image forming unit disposed above the sheet feeding unit 2. Unit 4, fixing unit 5 disposed on the paper discharge side of image forming unit 4, image reading unit 6 disposed above image forming unit 4 and fixing unit 5, and toner supply container 120. ing.

  The paper feed unit 2 includes a plurality of paper feed cassettes 7 for containing paper 9, and the paper 9 from the paper feed cassette 7 selected by the paper feed roller 8 among the plurality of paper feed cassettes 7 is fed one by one. It is sent out to the transport unit 3.

  The paper 9 sent to the paper transport unit 3 is transported through the paper transport path 10 toward the image forming unit 4. The image forming unit 4 forms a toner image on a sheet 9 by an electrophotographic process. The image forming unit 4 is a photoconductor 11 supported so as to be rotatable in the direction of an arrow in FIG. A charging unit 12, an exposure unit 13, a developing device 14, a transfer unit 15, a cleaning unit 16, and a charge eliminating unit 17 are provided.

  The charging unit 12 includes a charging wire to which a high voltage is applied. When a predetermined potential is applied to the surface of the photoconductor 11 by corona discharge from the charging wire, the surface of the photoconductor 11 is uniformly charged. Then, when light based on the image data of the original read by the image reading unit 6 is irradiated to the photoconductor 11 by the exposure unit 13, the surface potential of the photoconductor 11 is selectively attenuated, and the surface of the photoconductor 11 is irradiated. An electrostatic latent image is formed.

  Next, the developing device 14 supplies toner to the surface of the photoconductor 11, and the electrostatic latent image on the surface of the photoconductor 11 is developed into a toner image. The toner image on the surface of the photoconductor 11 is transferred by the transfer unit 15 to the sheet 9 conveyed between the photoconductor 11 and the transfer unit 15. When the toner of the developing device 14 is consumed by the development, the toner is supplied from the toner supply container 120.

  The sheet 9 on which the toner image has been transferred is conveyed toward the fixing unit 5 disposed on the downstream side of the image forming unit 4 in the sheet conveying direction. In the fixing unit 5, the paper 9 is heated and pressed by the heating roller 18 heated by the heat source and the pressure roller 19 that is in pressure contact with the heating roller 18, and the toner image is melted and fixed on the paper 9. Next, the sheet 9 on which the toner image is fixed is discharged onto the discharge tray 21 by the discharge roller pair 20.

  After the sheet 9 is transferred by the transfer unit 15, the toner remaining on the surface of the photoconductor 11 is removed by the cleaning unit 16, and the residual charge on the surface of the photoconductor 11 is removed by the charge removing unit 17. Then, the photosensitive member 11 is charged again by the charging unit 12, and image formation is performed in the same manner.

  FIG. 2 is a cross-sectional view showing a configuration of the developing device 14 according to the first embodiment of the present invention used in the image forming apparatus 1 described above.

  The developing device 14 includes a developing container 22 that contains a two-component developer composed of toner and a magnetic carrier, a first stirring member 23 and a second stirring member 24 that stir and convey the developer, a developing roller 27, a regulation roller, A member 28, a toner concentration sensor 37, and a toner supply container 120 are provided.

  The developing container 22 constitutes an outline of the developing device 14, and is divided into a first transport path 22c and a second transport path 22d by a partition portion 22b protruding from the lower portion thereof, and is divided into a first transport path 22c and a second transport path 22d. Contains developer. Further, the developing container 22 rotatably holds the first and second stirring members 23 and 24 and the developing roller 27 and integrally holds the regulating member 28. Further, a replenishing port 42 that enables toner replenishment from the toner replenishing container 120 is provided on the upper wall of the developing container 22.

  The first stirring member 23 is provided in the first transport path 22c, and the second stirring member 24 is provided in the second transport path 22d. The first and second stirring members 23 and 24 stir the developer to charge the toner in the developer to a predetermined level, whereby the toner is held on the magnetic carrier. Communicating portions provided on both end sides in the longitudinal direction of the partition portion 22b (front and back direction of the paper surface of FIG. 2) of the partition portion 22b are transported while being stirred in the first transport path 22c by the rotation of the first stirring member 23. (Not shown) is conveyed to the second conveyance path 22d. Then, the developer is transported while being stirred in the second transport path 22 d by the rotation of the second stirring member 24, and is supplied from the second stirring member 24 to the developing roller 27.

  The developing roller 27 includes a fixed magnet body 25 and a developing sleeve 26. The developing sleeve 26 is made of a cylindrical nonmagnetic material and is rotatably supported by the developing container 22 at a position adjacent to the second stirring member 24. The fixed magnet body 25 is a permanent magnet fixed in the developing sleeve 26 and generates a magnetic field toward the developing sleeve 26. Further, the developing roller 27 is opposed to the photoconductor 11 that is an image carrier at a predetermined interval. This facing area is a developing area D for supplying the developer carried on the developing sleeve 26 toward the photoreceptor 11. Further, a developing bias 29 in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 26 in order to supply toner to the photoreceptor 11.

  The regulating member 28 regulates the developer carried on the surface of the developing sleeve 26 to a predetermined layer thickness. The regulating member 28 has a blade shape and is spaced substantially above the developing sleeve 26 from the surface of the developing sleeve 26 with a predetermined interval. And attached to the developing container 22.

  The developer supplied from the second stirring member 24 is carried on the surface of the developing sleeve 26 by the magnetic force of the fixed magnet body 25 in the developing sleeve 26. The carried developer is regulated to a predetermined layer thickness by the regulating member 28, and is conveyed toward the developing flow area D by the rotation of the developing sleeve 26 in the arrow direction. When a developing bias 29 is applied to the developing sleeve 26, a potential difference is generated between the developing sleeve 26 and the photoconductor 11 in the developing region D, and the toner on the developing sleeve 26 is supplied to the photoconductor 11 and the photoconductor. The electrostatic latent image on 11 is developed into a toner image.

  A toner concentration sensor 37 for detecting the toner concentration of the developer stored in the developing container 22 is disposed on the right side wall of the first transport path 22c. The toner concentration sensor 37 detects the magnetic permeability of the developer in the developing container 22 at regular time intervals, and based on this magnetic permeability, the mixing ratio of the toner of the developer contained in the developing container 22 and the magnetic carrier ( Toner density) is detected. When the toner concentration in the developing container 22 is detected by the toner concentration sensor 37 and the toner concentration in the developing container 22 becomes a predetermined value or less, the toner is supplied from the toner supply container 120 into the developing container 22.

  The toner replenishing container 120 is for replenishing toner to the developing container 22 and is disposed above the developing container 22. A conveying screw 122 is provided in the toner supply container 120. The conveying screw 122 extends in the longitudinal direction at the bottom of the toner replenishing container 120, and has a spiral blade formed in a spiral shape around the shaft portion at a constant pitch. A delivery port 120 a is arranged opposite to one end of the conveying screw 122. As the transport screw 122 rotates, the toner in the toner replenishing container 120 is transported toward the delivery port 120a, and the toner is supplied into the developing container 22 from the delivery port 120a via the replenishment port 42 of the developing container 22. .

  The center of gravity G of the developing device 14 configured as described above is located below the partition 22b of the developing container 220. The developing device 14 is formed with an inertia main shaft I that passes through the center of gravity G of the developing device 14 and extends in the longitudinal direction of the developing device 14 (the front and back direction in FIG. 2). In the present embodiment, the inertia main shaft I is positioned within the shaft diameter of a common drive shaft that rotates the developing roller 27 and the first and second stirring members 23 and 24. With this configuration, when the driving shaft is rotationally driven by a driving source such as a motor, the rotational moment of the developing device 14 due to the rotational driving of the driving shaft is suppressed, so that vibration due to the driving of the developing device 14 is suppressed, and the developing device 14 is further suppressed. Is less likely to be transmitted to the image forming apparatus 1 and vibration of the image forming apparatus 1 is suppressed.

  A detailed arrangement of the drive shaft is shown in FIG. FIG. 3 is a side view schematically showing the arrangement of the gear train of the developing device 14 of the first embodiment rotated by the drive shaft and the drive shaft.

  A plurality of gears for rotating the developing roller 27 and the first and second stirring members 23 and 24 (see FIG. 2) are rotatably attached to the side wall surface of the developing container 22. The first stirring gear 54 rotates the first stirring member 23 via the first stirring shaft 23a, the second stirring gear 56 rotates the second stirring member 24 via the second stirring shaft 24a, and further the developing gear. 57 rotates the developing roller 27 via the developing shaft 27a.

  The first stirring gear 54 meshes with the relay gear 55, the relay gear 55 is provided coaxially with the second stirring gear 56, and the developing gear 57 meshes with the second stirring gear 56. The second stirring gear 56 meshes with the drive gear 53, and the drive shaft 51 of the drive gear 53 is connected to a drive source such as a motor (not shown). The drive shaft 51 has a predetermined shaft diameter, but is arranged so that the inertia main shaft I extending in the longitudinal direction of the developing device 14 is located within the shaft diameter of the drive shaft 51.

  Therefore, when the drive shaft 51 is rotated by driving the motor, the drive gear 53 is rotated, and the second stirring gear 56 is further rotated, whereby the second stirring member 24 is rotated. Due to the rotation of the second stirring gear 56, the first stirring gear 54 rotates through the relay gear 55, and the first stirring member 23 rotates. Further, by the rotation of the second stirring gear 56, the developing gear 57 rotates and the developing roller 27 rotates. When the developing roller 27 and the first and second agitating members 23 and 24 rotate, the driving shaft 51 stably rotates and the developing device 14 vibrates because the inertial main shaft I is located within the shaft diameter of the driving shaft 51. The rotational moment to be suppressed is suppressed. Further, since the vibration of the developing device 14 is suppressed, the vibration of the image forming apparatus 1 is also suppressed.

  Note that the conveyance screw 122 (see FIG. 2) of the toner supply container 120 may be rotationally driven via the drive shaft 51 and the gear trains 53 to 57 of the above embodiment. Further, instead of the relay gear 55 of the above embodiment, an idle gear that meshes with the first stirring gear 54 and the second stirring gear 56 may be provided, and the first stirring gear 54 may be rotated by the idle gear. . In these cases, the same effects as those of the above embodiment can be obtained.

(Second Embodiment)
FIG. 4 is a side view schematically showing a developing device provided with a balancing member according to the second embodiment of the present invention. The arrangement of the drive shaft 51 and the balancing member 71 different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted hereinafter.

  As in the first embodiment, the developing device 14 in the second embodiment includes a developing container 22, a toner supply container 120, a developing roller 27, and first and second stirring members 23 and 24, and the center of gravity G of the developing device 14 is provided. The inertia main shaft Ia extending in the longitudinal direction of the developing device 14 is positioned below the partition portion 22b of the developing container 22.

  A developing gear 57, a first stirring gear 54, and a second stirring gear 56 are rotatably attached to the side wall surface of the developing container 22. The second stirring gear 56 meshes with the first stirring gear 54, and the first stirring gear 54 meshes with the developing gear 57. A drive gear 53 and an idle gear 58 are rotatably attached to a side plate (not shown). The drive gear 53 and the idle gear 58 are disposed on the upper right side of the developing container 22, and the idle gear 58 meshes with the first stirring gear 54 and meshes with the drive gear 53. The drive shaft 51 of the drive gear 53 is connected to a drive source such as a motor (not shown).

  The drive shaft 51 is disposed at a position spaced apart from the inertia main shaft Ia of the developing device 14 on the upper right side. In this arrangement, when the drive shaft 51 is rotationally driven by a motor, the drive shaft 51 is relatively in relation to the inertia main shaft Ia. A large rotational moment acts and the developing device 14 vibrates.

  Therefore, a balancing member 71 having a predetermined mass is attached to the developing container 22 so that the inertial main shaft Ia of the developing device 14 is positioned within the shaft diameter of the drive shaft 51. By attaching the balancing member 71 to a predetermined position of the developing container 22, the inertia main shaft Ia moves to the inertia main shaft Ib, and the inertia main shaft Ib is positioned within the shaft diameter of the drive shaft 51.

  Accordingly, when the drive shaft 51 is rotated by driving the motor, the drive gear 53 is rotated, and the rotational force of the drive gear 53 is transmitted in the order of the idle gear 58, the first stirring gear 54, the second stirring gear 56, and the developing gear 57, The developing roller 27, the first and second stirring members 23, 24 rotate. When the developing roller 27 and the first and second stirring members 23 and 24 rotate, the drive shaft 51 stably rotates and the developing device 14 vibrates because the inertial main shaft Ib is positioned within the shaft diameter of the drive shaft 51. The rotational moment to be suppressed is suppressed. Further, since the vibration of the developing device 14 is suppressed, the vibration of the image forming apparatus 1 is also suppressed.

(Third embodiment)
FIG. 5 is a side view schematically showing a developing device holding a balancing member according to the third embodiment of the present invention. In the third embodiment, the developing device 14 holds the balancing member 71 provided in the image forming apparatus 1 as the developing device 14 is attached to the image forming apparatus 1. In the third embodiment, the developing roller 27, the gear train for rotating the first and second stirring members 23 and 24, and the drive shaft 51 have the same arrangement and configuration as in the second embodiment, and the developing device 14 itself. The inertia main axis Ia is arranged at the same position as in the second embodiment.

  A balance member 71 having a predetermined mass is supported on the apparatus main body 1 a of the image forming apparatus 1 by a hanging strap 72 so as to be movable in the vertical direction. The balancing member 71 is disposed at a predetermined position near the developing device 14.

  The developing device 14 is detachably attached to the image forming apparatus 1. When the toner in the toner replenishing container 120 is used up to a predetermined amount, the developing device 14 is removed from the image forming apparatus 1 and the toner replenishing container 120 is filled with toner. Alternatively, it is replaced with a new developing device 14 and attached to the image forming apparatus 1. The developing container 22 is provided with a lifting portion 73 protruding so that the lifting portion 73 faces the balancing member 71 and holds the balancing member 71 in a state where the developing device 14 is mounted on the image forming apparatus 1.

  When the developing device 14 is detached from the image forming apparatus 1, the balancing member 71 is held in a state where it is suspended by the hanging strap 72 (a state in which the balancing member 71 in FIG. 5 is lowered). When the developing device 14 is attached to the image forming apparatus 1, the lifting portion 73 enters below the balancing member 71 and lifts the balancing member 71. And the balance member 71 is hold | maintained in the state which slung the hanging string 72 (state of FIG. 5). In a state where the developing device 14 holds the balancing member 71, the inertia main shaft Ia moves to the inertia main shaft Ib, and the inertia main shaft Ib is positioned within the shaft diameter of the drive shaft 51.

  Accordingly, when the drive shaft 51 is rotated by driving the motor, the drive gear 53 is rotated, and the rotational force of the drive gear 53 is transmitted in the order of the idle gear 58, the first stirring gear 54, the second stirring gear 56, and the developing gear 57, The developing roller 27, the first and second stirring members 23, 24 rotate. When the developing roller 27 and the first and second stirring members 23 and 24 rotate, the drive shaft 51 stably rotates and the developing device 14 vibrates because the inertial main shaft Ib is positioned within the shaft diameter of the drive shaft 51. The rotational moment to be suppressed is suppressed. Furthermore, since the vibration of the developing device 14 is suppressed, the vibration of the image forming apparatus 1 is also suppressed.

  Note that the lifting portion 73 of the above-described embodiment may have a slope-shaped tip on the insertion side of the developing device 14 so that the lifting portion 73 can easily enter below the balancing member 71 when lifting the balancing member 71. Further, instead of the configuration in which the balancing member 71 is suspended by the hanging strap 72, when the balancing member 71 is placed on a pedestal provided in the apparatus main body 1a and the developing device 14 is attached to the image forming apparatus 1, the lifting portion 73 is The structure may be such that it enters between the lower surface portion of the balancing member 71 and lifts and holds the balancing member 71.

(Fourth embodiment)
FIG. 6 is a side view showing the configuration of the developing device 14 and its periphery according to the fourth embodiment of the present invention. The fourth embodiment includes a configuration in which the balancing member 71 is moved in accordance with the amount of toner in the toner supply container 120, and is suitable for a high-speed image forming apparatus capable of printing a large amount. In the first to third embodiments, the capacity of the toner supply container 120 is relatively small, and the influence of the change in the toner amount in the toner supply container 120 when setting the position of the center of gravity is small, but in the fourth embodiment, This is a case where a large amount of toner is stored in the toner replenishing container 120, and thus the change in the toner weight cannot be ignored. In the fourth embodiment, the gear train for rotating the developing roller 27, the first and second stirring members 23 and 24, and the drive shaft 51 have the same arrangement and configuration as those in the second and third embodiments.

  In the present embodiment, the position of the center of gravity of the developing device 14 changes when the toner supply container 120 is full of toner and when the toner in the toner supply container 120 is nearly empty. When the toner is full, the center of gravity is positioned on the upper side, but when the toner is nearly empty, the center of gravity is positioned on the lower side. Therefore, when the toner supply container 120 is full of toner, the inertia main axis Ia1 passing through the center of gravity of the developing device 14 is at the uppermost position, and the inertia main axis decreases as the toner in the toner supply container 120 decreases. When the toner in the toner replenishing container 120 becomes almost empty and needs to be replaced, the inertia main shaft Ia2 is at the lowest position.

  On the outer wall of the developing container 22 is provided a balancing member 71 that can move in the vertical direction and cannot rotate. The balancing member 71 is moved up and down between the solid line position and the broken line position in FIG. 6 by the driving means. The driving means includes a feed screw member 75, gears 76 and 77, and a motor 78.

  The feed screw member 75 is rod-shaped and is erected on the apparatus main body 1 a of the image forming apparatus 1 so as to be rotatable. The feed screw member 75 is screwed into the female screw of the balancing member 71. When the feed screw member 75 rotates, the balance member 71 is moved in the vertical direction by the screwing of the feed screw member 75 and the balance member 71.

  A gear 76 is fixed below the feed screw member 75, and the gear 76 meshes with a gear 77 that is rotated by a motor 78. When the motor 78 is driven to rotate in the forward direction, the feed screw member 75 is rotated in the forward direction via the gears 77 and 78, and the balance member 71 is raised by the rotation of the feed screw member 75 and moved from the solid line position to the broken line position. When the motor 78 is driven to rotate in the reverse direction, the feed screw member 75 is rotated in the reverse direction via the gears 76 and 77, and the balance member 71 is lowered by the rotation of the feed screw member 75 and moved from the broken line position to the solid line position.

  The motor 78 is connected to the control unit 91. The control unit 91 is connected to a print counting unit 92 together with a motor 78, and includes a storage element such as a microcomputer, a RAM, and a ROM. The control unit 91 refers to the program and data set in the storage element, and controls the rotation direction and the rotation amount of the motor 78 based on the print time data input from the print counting unit 92.

  The print counting unit 92 counts and accumulates the printing time each time printing is performed from when the toner supply container 120 filled with toner is mounted on the image forming apparatus 1, and outputs the accumulated printing time to the control unit 91.

  The control unit 91 calculates the toner amount in the toner supply container 120 based on the cumulative printing time input from the print counting unit 92, and further calculates the driving amount of the motor 78 from the calculation result. Specifically, when the toner supply container 120 is full of toner, the motor 78 is driven and controlled so that the balancing member 71 is held at the solid line position, and as the toner in the toner supply container 120 decreases, The motor 78 is driven and controlled so that the balancing member 71 moves upward from the solid line position. When the toner in the toner supply container 120 becomes almost empty, the motor 78 is held so that the balancing member 71 is held at the broken line position. Drive control.

  When the toner supply container 120 is full of toner by the control of the control unit 91, the inertial main axis Ia1 of the developing device 14 when the balancing member 71 is not attached is moved to the inertial main axis Ib, and the inertial main axis Ib is the drive axis. It will be located within the shaft diameter of 51. Further, when the toner in the toner supply container 120 becomes almost empty, the inertial main axis Ia2 of the developing device 14 when the balancing member 71 is not attached moves to the inertial main axis Ib. Further, as the toner in the toner replenishing container 120 decreases (the cumulative printing time increases), the inertial spindle moves from the inertial spindle Ia1 to the inertial spindle Ia2, but the balance member 71 gradually rises so Is always held on the inertial spindle Ib.

  Therefore, even if the amount of toner in the toner replenishing container 120 changes, the drive shaft 51 stably rotates and the developing device 14 tries to vibrate because the inertia main shaft Ib is positioned within the shaft diameter of the drive shaft 51. The rotational moment can be suppressed. Further, the driving of the developing device 14 is not easily transmitted to the image forming apparatus 1, and the vibration of the image forming apparatus 1 is suppressed.

  In the above embodiment, the configuration in which the print counting unit 92 outputs the cumulative printing time to the control unit 91 has been described. However, the present invention is not limited to this, and the print counting unit 92 outputs the cumulative number of printed sheets to the control unit 91. Then, the control unit 91 may drive the motor 78 based on the cumulative number of printed sheets, and the inertia main shaft Ib may be positioned within the shaft diameter of the drive shaft 51.

  In the above-described embodiment, the feed screw member 75 rotated by the motor 78 is used as the drive unit. However, the feed screw member 75 may be replaced with another member. For example, the structure which the movement member holding the lower surface of the balance member movable to an up-down direction moves to an up-down direction by drive sources, such as a motor, may be sufficient.

(Fifth embodiment)
The invention according to the fifth embodiment of the present invention has a configuration in which the balancing member 71 is moved in accordance with the amount of toner in the toner supply container 120, and is suitable for a high-speed image forming apparatus capable of performing a large amount of printing. The fifth embodiment is different from the fourth embodiment in that the balance member 71 moves in the vertical direction as in the fourth embodiment, but the balance member 71 further swings in the horizontal direction. FIG. 7 is a plan view schematically showing a developing device provided with a weight sensor, and FIG. 8 is a side view showing a configuration for operating a balancing member. In the fifth embodiment, the developing roller 27, the gear train that rotates the first and second stirring members 23 and 24, and the drive shaft 51 have the same arrangement and configuration as in the fourth embodiment.

  In this embodiment, when the toner supply container 120 is full of toner and when the toner in the toner supply container 120 is nearly empty, the position of the center of gravity of the developing device 14 changes. However, when the toner is nearly empty, the center of gravity is located on the lower side. Further, when the amount of toner stored in the toner replenishing container 120 is biased in the longitudinal direction (front and back direction in FIG. 8), the position of the center of gravity of the developing device 14 varies in the longitudinal direction of the developing device 14.

  Therefore, as shown in FIG. 7, a plurality (three in this embodiment) of weight sensors 94 are provided to detect the position of the center of gravity according to the change in the toner amount in the toner supply container 120. The weight sensor 94 is composed of a strain gauge or the like and is disposed on the lower surface of the developing device 14. Two weight sensors 94 are arranged at the corners at both ends in the longitudinal direction (vertical direction in FIG. 7) of the developing device 14, and one weight sensor 94 is arranged at the center of the other side extending in the longitudinal direction.

  As shown in FIG. 8, detection results of the plurality of weight sensors 94 are input to the control unit 91. The control unit 91 calculates the center-of-gravity position in the vertical direction and the center-of-gravity position in the longitudinal direction based on the detection result (weight data) of each weight sensor 94 and the arrangement position of each weight sensor 94.

  Further, the control unit 91 controls the driving means based on the calculated gravity center position data in order to move the balancing member 71 in the vertical direction and to swing it in the horizontal direction. The drive means includes a feed screw member 80, gears 76 and 77, a motor 78 and a swing motor 81.

  The feed screw member 80 is erected on the image forming apparatus 1 so as to be rotatable in a bar shape and swingable in the horizontal direction, and is screwed into the female screw of the balancing member 71. When the feed screw member 80 rotates, the balance member 71 is moved in the vertical direction by the screwing of the feed screw member 80 and the balance member 71. Further, when the feed screw member 80 swings in the front and back direction in FIG. 8, the balancing member 71 swings similarly to the feed screw member 80. The swing member 71 is provided at the central portion in the longitudinal direction of the outer wall of the developing container 22 so as to be movable in the vertical direction and swingable in the horizontal direction.

  A gear 76 is fixed below the feed screw member 80, and the gear 76 meshes with a gear 77 that is rotated by a motor 78. When the motor 78 is rotationally driven in the forward direction, the feed screw member 80 is rotated in the forward direction via the gears 77 and 78, and the balance member 71 is raised by the rotation of the feed screw member 80 and moved from the solid line position to the broken line position. When the motor 78 is rotationally driven in the reverse direction, the feed screw member 80 is rotated in the reverse direction via the gears 76 and 77, and the balance member 71 is lowered by the rotation of the feed screw member 80 and moved from the broken line position to the solid line position.

  Further, a swing motor 81 for swinging the feed screw member 80 is provided at the swing support point 82 of the feed screw member 80. The feed screw member 80 maintains the meshed state of the gears 76 and 77 while the swing motor 81 is swung. While swinging to one side by the forward rotation drive, the swinging motor 81 swings to the other side. When the feed screw member 80 is swung, the balancing member 71 is swung in the front and back direction in FIG.

  The control unit 91 calculates the center of gravity position of the developing device 14 based on the weight data input from the weight sensor 94, and calculates the drive amounts of the motor 78 and the swing motor 81 from the center of gravity position data.

  Specifically, based on the calculation result of the center of gravity position in the vertical direction, the controller 91 determines that the center of gravity of the developing device 14 when the balance member 71 is not attached is G1 (the inertia main axis is Ia1). The motor 78 is controlled so that 71 is held at the solid line position, and the motor 78 is controlled so that the balancing member 71 moves upward from the solid line position as the center of gravity of the developing device 14 similar to the above is lowered. Further, when the center of gravity of the developing device 14 is G2 (the inertia main axis is Ia2), the motor 78 is controlled so that the balancing member 71 is held at the broken line position.

  Further, based on the calculation result of the longitudinal center of gravity position by the weight sensor 94, the control unit 91 swings in a direction to correct the deviation when the longitudinal center of gravity position of the developing device 14 is offset from the central part. The motor 81 is driven.

  When the center of gravity of the developing device 14 fluctuates in the vertical direction by the control of the control unit 91, the inertia main shafts Ia1 and Ia2 of the developing device 14 when the balancing member 71 is not attached are moved to the inertia main shaft Ib, and the inertia main shaft Ib Is located within the shaft diameter of the drive shaft 51. Further, as the toner in the toner replenishing container 120 decreases, the inertia main axis is always held on the inertia main axis Ib even if the inertia main axis moves from the inertia main axis Ia1 to the inertia main axis Ia2. Further, when the center of gravity of the developing device 14 is biased in the longitudinal direction, the center of gravity is moved to the center in the longitudinal direction.

  Therefore, even if the toner amount in the toner supply container 120 changes or toner is unevenly distributed in the toner supply container 120, the inertial main shaft Ib is positioned within the shaft diameter of the drive shaft 51, so that the drive shaft 51 is stabilized. Thus, the rotational moment that causes the developing device 14 to vibrate is suppressed. Further, the driving of the developing device 14 is not easily transmitted to the image forming apparatus 1, and the vibration of the image forming apparatus 1 is suppressed.

  The present invention can be used for a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multi-function machine thereof, and an image forming apparatus including the developing device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1a Apparatus main body 11 Photoconductor 14 Developing apparatus 22 Developing container 23 1st stirring member 23a 1st stirring shaft 24 2nd stirring member 24a 2nd stirring shaft 27 Developing roller 27a Developing shaft 42 Supply port 51 Drive shaft 53 Drive Gear 54 First stirring gear 55 Relay gear 56 Second stirring gear 57 Development gear 58 Idle gear 71 Balance member 72 Suspension string 73 Lifting portion 75, 80 Feed screw member (drive means)
76, 77 gear (drive means)
78 Motor (drive means)
81 Swing motor (drive means)
91 Control unit (control means)
92 Print Count Unit (Print Count Unit)
94 Weight sensor 120 Toner supply container 120a Outlet 122 Conveying screw I, Ia, Ia1, Ia2, Ib Inertial spindle

Claims (3)

A developer container for containing toner;
An agitating member for agitating and conveying the toner in the developing container;
A developing roller for supplying the toner conveyed from the stirring member to the image carrier;
A detachable developing device having a driving shaft for transmitting a rotational force from a driving source to the stirring member and the developing roller;
An image forming apparatus comprising: a balancing member having a predetermined mass and movable in the vertical direction;
By mounting the developing device, the balancing member is held at a predetermined position of the developing device, and an inertia main shaft extending in the longitudinal direction of the developing device through the center of gravity of the developing device is within the shaft diameter of the driving shaft. An image forming apparatus that is positioned. A developer container for containing toner;
An agitating member for agitating and conveying the toner in the developing container;
A developing roller for supplying the toner conveyed from the stirring member to the image carrier;
A drive shaft for transmitting a rotational force from a drive source to the stirring member and the developing roller;
A toner replenishing container that is detachable from the developing container and stores toner to be replenished in the developing container;
A developing device having a balancing member having a predetermined mass and movable in the vertical direction;
Driving means for moving the balancing member in the vertical direction;
Print counting means for accumulating the accumulated printing time or the accumulated number of printed sheets from when the toner supply container filled with toner is installed;
The drive means is driven based on the total printing time or the total number of printed sheets of the print counting means, and the inertia main shaft extending in the longitudinal direction of the developing device through the center of gravity of the developing device is positioned within the shaft diameter of the driving shaft. And an image forming apparatus comprising: a control unit configured to perform control. A developer container for containing toner;
An agitating member for agitating and conveying the toner in the developing container;
A developing roller for supplying the toner conveyed from the stirring member to the image carrier;
A drive shaft for transmitting a rotational force from a drive source to the stirring member and the developing roller;
A toner supply container for storing toner to be supplied to the developer container;
A developing device having a balancing member that has a predetermined mass and is movable in the vertical direction and swingable in the horizontal direction;
Driving means for moving the balancing member in the vertical direction and swinging it horizontally around the lower end;
A plurality of weight sensors disposed at predetermined positions of the developing device and measuring the weight of the developing device;
Inertia extending in the longitudinal direction of the developing device through the center of gravity of the developing device by calculating the center of gravity of the developing device based on the outputs of the plurality of weight sensors and driving the driving means according to the position of the center of gravity. An image forming apparatus comprising: a control unit configured to control the main shaft so as to be positioned within the shaft diameter of the drive shaft.

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