Field of the Invention
The present invention relates to a developer storage unit to be used in an electrophotographic image forming apparatus, a development device including the developer storage unit, a process cartridge, and the electrophotographic image forming apparatus.
Here, the electrophotographic image forming apparatus is an apparatus for forming an image on a recording material by employing electrophotographic image forming processing. The electrophotographic image forming apparatus includes, for example, a copying machine, a printer (a laser beam printer, a light-emitting diode (LED) printer, or the like), a facsimile apparatus, a word processor, or the like.
The developer storage unit is a unit for storing a developer to be used in the electrophotographic image forming processing, and includes a developer storage chamber for storing the developer, a stirring-conveying unit for stirring and conveying the developer stored in the developer storage chamber, and the like.
The development device is a device for visualizing an electrostatic image on an electrophotographic photosensitive member (photosensitive member) using the developer in the electrophotographic image forming processing.
In general, the process cartridge is a unit which is formed by integrating a photosensitive member into a process unit operating on the photosensitive member as a cartridge and detachably mounted on the apparatus main body of the electrophotographic image forming apparatus. A charging unit, a development unit, and a cleaning unit can be given as the examples of the process units. In an exemplary embodiment of the present invention, the process cartridge is a unit configured by integrally forming the photosensitive member and at least the development device into a cartridge, and detachably mounted on the apparatus main body of the electrophotographic image forming apparatus.
Description of the Related Art
Conventionally, as a method for filling a developer storage chamber with a developer, a method in which a filling port for supplying the developer is provided on a frame forming the developer storage chamber, and the filling port is sealed with a sealing member such as a cap after the developer is supplied through the filling port has been widely employed.
However, with the above-described method, because the sealing member has to be provided separately, this method may cause an increase in number of components and an increase in number of steps in assembly processing. In addition, in many cases, a rotatable conveyance unit as a stirring-conveying unit for stirring and conveying the developer is provided within the developer storage chamber. In this case, depending on the phase of the conveyance unit stopped within the developer storage chamber, a conveyance member such as a sheet attached to a rotating shaft of the conveyance unit may interrupt the filling of the developer through the filling port. Therefore, there may be a case where the attachment phase of the conveyance unit has to be controlled.
With respect to the above issue, a method in which a hollow space is provided within the conveyance unit to supply the developer via the hollow space has been discussed (Japanese Patent Application Laid-Open No. 2002-341635).
In this method, a hole previously provided on a frame, through which a drive transmission member such as a drive transmission gear for transmitting a driving force to the conveyance unit is inserted within the developer storage chamber, is used as a filling port, so that the developer is supplied through the filling port by accessing the conveyance unit. After the developer has been filled, the filling port is sealed with an existing sealing member that seals a space between the drive transmission member and the frame. Therefore, a dedicated filling port or a dedicated sealing member does not have to be provided separately, and thus the number of components or the number of steps in assembly processing can be reduced. In addition, because the developer is filled via the interior of the conveyance unit, the conveyance member attached to the rotating shaft of the conveyance unit is less likely to interrupt the developer that is being filled, and thus the filling efficiency of the developer can be further improved.
Conventionally, in the image forming apparatus employing the electrophotographic image forming processing, a cartridge system has been employed. In the cartridge system, a developer storage unit or a development device formed into a cartridge, or a cartridge such as a process cartridge is detachably mounted on the apparatus main body of the image forming apparatus.
In the above-described cartridge system, in order to enable a user to replace the cartridge at an appropriate timing, a function of displaying information about remaining printable pages may be added. In order to add the above function, in general, the remaining amount of the developer within the cartridge is detected or estimated, and thus various methods therefor are discussed.
Of the various methods therefor, a light transmission-type developer remaining amount detection method has been widely employed. In this method, a light guiding member as a remaining amount detection unit including a light guide and a light transmission window is provided on the developer storage chamber. Further, a light path passing through the developer storage chamber via the light guiding member is formed by a light emitting element such as a light-emitting diode (LED) and a light receiving element such as a phototransistor which are mounted on the apparatus main body of the electrophotographic image forming apparatus. Then, the remaining amount of the developer is detected from a period of time in which the developer blocks the light path (Japanese Patent Application Laid-Open No. 2001-318524).
However, in the above-described light transmission-type developer remaining amount detection method, the developer that is stirred and conveyed by the conveyance unit may scatter within the developer storage chamber, and thus the scattered developer may block a light signal. In this case, disturbances may occur in a light receiving signal, so that detection accuracy of the developer remaining amount may be deteriorated.
With respect to the above-described issue, a method in which a receiving portion for receiving the developer falling from the conveyance member is provided on a rotating shaft within the developer storage chamber to suppress the scattering of developer has been discussed (Japanese Patent Application Laid-Open No. 2010-009021).
In order to fill the developer storage unit having such a complicated structure with the developer, further technical development has been required.