JPH0636059U - Image forming device developing device - Google Patents

Abstract

(57) [Abstract] [Purpose] A developing device of an image forming apparatus capable of automatically collecting the developer in the developer discharge portion of the developer container according to the decrease of the developer with a simple and low-cost configuration. provide. [Structure] A bottom plate 18 is provided in a developer container 16 for containing a developer.
From the sideways posture along the bottom surface of the developer container 16 to its bottom plate.
The developer on 18 is pivotally supported so as to be rotatable up to an inclined posture where the developer gathers in the developer discharge portion of the developer container 16. Only when the load applied to the output shaft is less than or equal to the set value, the rotation of the drive shaft 19 of the developer container 16 is rotated by the bottom plate 18 through the torque limiting rotation transmission device 24 which transmits the rotation of the input shaft to the output shaft. It is configured to be transmitted to a pivot shaft 21 fixed to.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a developing device in an image forming apparatus such as an electrostatic photocopier.

[0002]

[Prior art]

 As a conventional example of this type of developing device, one having the following configuration is well known. A movable bottom plate is provided in the developer container that contains the developer, and this bottom plate is biased by a spring to the rising side in an inclined posture, so that the developer on the bottom plate decreases and the load of the developer on the bottom plate is reduced. The bottom plate is tilted when the biasing force of the spring prevails, so that the developer is collected in the developer discharge portion of the developer container (Japanese Utility Model Laid-Open No. 1-123862). By laying a sheet so that it can be rolled up in the developer container, and detecting the decrease in the developer in the developer container by a sensor, when the decrease in the developer is detected, the sheet is wound up manually or automatically. The developer is collected in the developer discharge portion of the developer container (Japanese Patent Laid-Open No. 63-223667). An extruding member that can extrude the developer is provided in the developer discharge section of the developer container, and a pressing member made of a shape memory alloy is connected to this extruding member, and when the sensor detects that the developer has decreased, this Accordingly, the pushing member pushes out the pushing member by restoring the shape of the pushing member, whereby the developer is collected in the developer discharging portion (Japanese Patent Laid-Open No. 2-69787). A rotation speed of a developer discharge roller provided in a developer discharge portion of a developer container is increased in response to the detection of the decrease (JP-A-3-29982).

[0003]

[Problems to be solved by the device]

 However, the conventional developing device described above has the following problems. In the case of the configuration, although the mechanism is simple and the cost is not so high, when the developer is filled in the developer container, the bottom plate biased to the rising side by the spring is pressed against the container bottom against the spring. It is necessary to fill the developer in advance, which not only complicates the filling work, but also reduces the biasing force of the spring due to use, which may cause a malfunction. In the case of the constructions (1) to (4), a sensor or the like is required to detect the decrease of the developer in the developer container, which causes a problem of increasing cost. Further, in the case of the above configuration, it is not easy to properly set the sheet in the developer container, which causes a problem in manufacturing. Further, in the case of the above configuration, in order to restore the shape of the pressing member made of the shape memory alloy, a mechanism for heating the pressing member is required, which complicates the structure. Also in the case of this configuration, a separate drive system is required to increase the rotation speed of the developer discharge roller, which complicates the configuration.

The present invention has been made in consideration of such a situation, and with a simple and low-cost configuration, the developer is automatically collected in the developer discharge portion of the developer container according to the decrease of the developer. An object of the present invention is to provide a developing device for an image forming apparatus that can be mounted on the image forming apparatus.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the developing device of the image forming apparatus of the present invention has a bottom plate in a developer container for accommodating the developer, and a bottom plate on the bottom plate from a sideways posture along the bottom surface of the developer container. The developer is pivotally supported so that it can be rotated to an inclined posture where it collects in the developer discharge part of the developer container, and the rotation of the input shaft is transmitted to the output shaft only when the load applied to the output shaft is less than the set value. It is characterized in that the rotation of the drive shaft of the developer container is transmitted to a pivot shaft fixed to the bottom plate through the torque limiting rotation transmission device.

[0006]

[Action]

 When the developer is sufficiently loaded on the bottom plate, the load applied to the pivot of the bottom plate is large, so the torque limiting rotation transmission device does not transmit the rotation of the drive shaft in the developer container to the pivot of the bottom plate, Does not rise to a tilted posture. When the amount of developer decreases and the load on the pivot of the bottom plate decreases, the rotation of the drive shaft is transmitted to the pivot of the bottom plate via the torque limiting rotation transmission device, and the bottom plate changes from the sideways tilted position to the tilted position. To do. As a result, the developer on the bottom plate is collected in the developer discharge portion of the developer container.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view of the back of the electrostatographic copying machine showing the structure in the vicinity of the developing section, FIG. 2 is a plan view thereof, and FIG.

In the electrostatographic copying machine to which this embodiment is applied, a photosensitive drum 2 having a photosensitive member 1 on its outer peripheral surface is horizontally mounted on a main body 3 of the copying machine, and a charging device is provided around the photosensitive member 1. 4, the optical system moving type exposure device 5, the developing device 6, the charge type transfer device 7, the copy paper separating device 8 and the cleaning device 9 are arranged in this order in the rotation direction of the photoconductor 1 (indicated by the arrow R). It is located in. Further, a paper feed / conveyance means 11 is arranged from the paper feed section 10 to the transfer device 7, and a paper discharge / transport means 13 is arranged from the copy paper separation device 8 to the fixing device 12, respectively, and a paper discharge roller pair is arranged. 14 and a paper ejection tray 15 are provided.

As shown in FIG. 1, in the developer container 16 of the developing device 6, a developing sleeve 17 is rotatably disposed so as to face the developer discharging portion 16 a, and the developing sleeve 16 is At the rear, a bottom plate 18 is pivotally supported so as to be rotatable from a sideways posture along the bottom portion of the developer container 16 to an inclined posture in which it stands up toward the developing sleeve 17 side. A rotary shaft 19 of a developing sleeve 17, which is a drive shaft in the developing device 6, is linked to a pivot shaft 21 of the bottom plate 18 via a rotation transmission mechanism 20.

The rotation transmission mechanism 20 includes an input gear 22 fixed to a rotation shaft 19 of the developing sleeve 17, an output gear 23 meshed with the input gear 22 and rotatably provided on a pivot shaft 21 of the bottom plate 18. A torque limiting rotation transmission device 24 that is interposed between the output gear 23 and the pivot 21 of the bottom plate 18 and transmits the rotation of the output gear 23 to the pivot 21 of the bottom plate 18 under the conditions described later. To be done.

The torque limiting rotation transmission device 24 is made up of a cylindrical bracket 25 that is rotatably fitted to a pivot shaft 21 of the bottom plate 18 as shown in FIG. 4, and a steel material fixed to the inner peripheral surface of the bracket 25. And a driven member 27 which is made of steel and holds a magnet 28 and which is fixed to the pivot 21 of the bottom plate 18. The driven side member 27 is disposed on the inner peripheral side facing the driving side member 26, and iron powder 29 is sealed in the gap between the driving side member 26 and the driven side member 27 by the magnetic force of the magnet 28. The output gear 23 is fixed to one end of the bracket 25. With this configuration, the rotation of the output gear 23, that is, the rotation of the bracket 25 causes the coupling force between the driving-side member 26 and the driven-side member 27 in which the iron powder 29 is present, and the operating surface of the driving-side member 26 and the driven side. When the frictional force between the side member 27 and the operating surface is larger than the load applied to the bottom plate 17, the frictional force is transmitted to the pivot 21 of the bottom plate 18 via the driven side member 27, and the bottom plate is stronger than the connecting force and the frictional force. When the load applied to the pivots 21 of 18 is large, the rotation of the output gear 23 is not transmitted to the pivots 21.

A regulation plate 30 is provided on the ceiling of the developer container 16 for regulating the bottom plate 18 which is rotated from the bottom and stands up in a tilted position. A comb tooth-shaped notch 30a is formed at the lower end of the regulation plate 30 to allow the developer to pass to the developing sleeve 17 side.

Next, the operation of the developing device 6 will be described. In the developing device 6, the developer filled in the developer container 16 adheres to the developing sleeve 17, and the developing sleeve 17 is rotated by driving a motor (not shown), so that the attached developer is charged by a blade (not shown). As it is formed, it is adhered to the surface of the photoconductor 1 with a uniform layer thickness. By the operation, the latent image on the surface of the photoconductor 1 is revealed.

At this time, the rotation of the input gear 22 fixed to the rotary shaft 19 of the developing sleeve 17 is transmitted to the output gear 23, and the output gear 23 rotates in the clockwise direction indicated by the arrow r in FIG. The rotation of the output gear 23 is transmitted to the bracket 25 of the torque limiting rotation transmission device 24 having the gear 23 fixed at one end, that is, the driving side member 26. When the developer container 16 is sufficiently filled with the developer, the bottom plate 18 has a higher frictional force than the above-described coupling force and friction force between the driving side member 26 and the driven side member 27 in the torque limiting rotation transmission device 24. When the applied load is large, the rotation of the driving member 26 is not transmitted to the driven member 27. That is, the rotation of the developing sleeve 17 is not transmitted to the pivot 21 of the bottom plate 18, and the bottom plate 18 is kept in a horizontal position along the bottom of the developer container 18 as shown by the solid line in FIG.

As the amount of the developer in the developer container 18 decreases, the load applied to the bottom plate 18 is the above-mentioned coupling force and frictional force between the driving side member 26 and the driven side member 27 of the torque limiting rotation transmission device 24. When it becomes smaller than the above, the rotation of the driving side member 26 is transmitted to the driven side member 27. That is, the rotation of the developing sleeve 17 is transmitted to the pivot 21 of the bottom plate 18 through the rotation transmission mechanism 20, and the bottom plate 18 rises while rotating from the sideways posture shown by the solid line in FIG. 1 to the inclined posture shown by the chain line. As a result, the developer remaining on the bottom plate 18 behind the developing sleeve 17 is collected on the developing sleeve 17 side due to the inclination of the bottom plate 18.

When replenishing the developer container 16 with the developer, the above-mentioned coupling force and frictional force between the driving-side member 26 and the driven-side member 27 in the torque limiting rotation transmission device 24 are resisted. By pushing down the bottom plate 18, it is possible to easily return to the original sideways posture without being hindered by the rotation transmission mechanism 20.

FIG. 5 is a sectional view showing another embodiment of the developing device of the present invention. The developing device 31 of this embodiment is a two-chamber type developing device in which a lower half portion of the housing 32 has a developer supply chamber 35 having a developing sleeve 33 and an upper half portion has a developer container 36. In the developer supply chamber 35, a developing sleeve 33 is rotatably arranged so as to face an opening 35a facing the surface of the photoconductor 1, and the surface of the developing sleeve 33 is provided behind the developing sleeve 33. A sub-roller 37 for adhering the developer to is rotatably arranged.

In the developer discharge portion 36 a which is opened at the bottom of the developer container 36 and communicates with the developer supply chamber 35, a supply roller 38 which supplies the developer in the developer container 36 to the developer supply chamber 35 in a fixed amount. The bottom plate 39 is pivotally supported on the other part of the bottom portion so as to be able to stand up by pivoting from a sideways posture to a tilted posture toward the supply Lara 38 side. A rotation shaft 34 of a developing sleeve 33, which is a drive shaft of the developing device 31, is linked to a pivot shaft 40 of the bottom plate 39 via a rotation transmission mechanism 41 which is substantially the same as that of the previous embodiment.

That is, the rotation transmission mechanism 41 includes an input gear 42 fixed to the rotary shaft 34 of the developing sleeve 33, an intermediate gear 43 meshing with the input gear 42, an output gear 44 meshing with the intermediate gear 43, It is composed of a torque limiting rotation transmission device 45 that transmits the rotation of the output gear 44 to the pivot 40 of the bottom plate 39. The torque limiting rotation transmission device 45 has the same configuration as that of the previous embodiment, and the rotation of the output gear 44, that is, the rotation of the developing sleeve 33 is prevented from rotating when the load applied to the bottom plate 39 is less than the set value. Communicate to 40.

Also in this embodiment, when the developer container 36 is sufficiently filled with the developer, the load due to the load of the developer is applied to the bottom plate 39, and the load is the torque limiting type rotation. Since the connecting force and the frictional force in the transmission device 45 are exceeded, the rotation of the developing sleeve 33 is not transmitted to the pivot 40 of the bottom plate 39, and the bottom plate 39 is maintained in the sideways posture shown by the solid line in FIG.

On the other hand, when the developer is reduced and the load applied to the bottom plate 39 becomes less than the coupling force and the frictional force in the torque limiting rotation transmission device 45, the rotation of the developing sleeve 33 causes the rotation of the pivot plate of the bottom plate 39. The bottom plate 39 is transmitted to 40 and is rotated from the sideways posture shown by the solid line in FIG. 5 to the inclined posture shown by the chain line. As a result, the developer left at a position away from the supply roller 38 is collected on the supply roller 38 side by the inclination of the bottom plate 39. Also in this embodiment, when replenishing the developer in the developer container 36, the bottom plate 39 is pushed down to the bottom of the developer container 36 so that the rotation transmitting mechanism 50 does not interfere and the bottom plate 39 can be easily removed. It is possible to return to the sideways posture.

In the developing device 31 of the two-chamber type, the bottom plate 18 and the rotation transmitting mechanism 20 having the same configuration as in the first embodiment are provided in the developing agent supply chamber 35 in the lower half portion having the developing sleeve 33. It may be provided. Further, the developing device of the present invention can be applied regardless of whether the developer used is a one-component type or a two-component type.

[0023]

[Effect of device]

 The present invention is configured as described above, in which the bottom plate is placed inside the developer container that contains the developer, and the developer on the bottom plate is discharged to the developing discharge portion of the developer container from the sideways posture along the bottom surface of the developer container. It is pivotally supported so that it can be rotated to a tilted posture, and the rotation of the input shaft is transmitted to the output shaft only when the load applied to the output shaft is below the set value. Since the rotation of the drive shaft of the developer container is transmitted to the pivot fixed to the bottom plate, the developer in the image developer container is reduced with a low cost and a simple structure. The developer remaining in a position apart from the developer discharge portion of the container can be automatically collected in the developer discharge portion.

[Brief description of drawings]

FIG. 1 is a back sectional view showing an embodiment of a developing device according to the present invention.

FIG. 2 is a horizontal sectional view of the developing device.

FIG. 3 is a cross-sectional view showing an outline of an electrostatographic copying machine in which the developing device is incorporated.

FIG. 4 is a partially cutaway plan view of a torque limiting rotation transmission device used in the developing device.

FIG. 5 is a back sectional view showing another embodiment of the developing device according to the present invention.

[Explanation of symbols]

16, 36 ... Developer container, 16a, 36a ... Developer discharge part, 18,
39 ... Bottom plate, 19, 34 ... Drive shaft, 21, 40 ... Axis, 24, 45 ... Torque limiting type rotation transmission device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junji Jouma 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Within Mita Kogyo Co., Ltd. (72) Shiseh Miyazaki 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka No. 28 in Mita Industry Co., Ltd. (72) Inventor Hiroyuki Arima 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Prefecture No. 28 Inside Mita Industry Co., Ltd. (72) Jun-ichi Inada 1-2-chome Tamatsukuri, Osaka-shi, Osaka No. 28 Mita Industry Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A bottom plate in a developer container for accommodating the developer, from a sideways posture along the bottom surface of the developer container to a tilted posture in which the developer on the bottom plate gathers in a developer discharge portion of the developer container. The developer is rotatably supported so that the rotation of the input shaft is transmitted to the output shaft only when the load applied to the output shaft is less than a set value. A developing device for an image forming apparatus, wherein rotation of a drive shaft of a container is transmitted to a pivot fixed to the bottom plate.