Patent Description:
As an electrophotographic image forming apparatus, there is known a configuration in which a development cartridge including a development roller is arranged below an intermediate transfer unit (<CIT> and <CIT>). A development chamber having the development roller of such a development cartridge disposed therein is provided above a toner containing chamber (a developer containing chamber) containing toner (a developer). This leads to the employment of a configuration that supplies the toner to the development chamber by rotating a stirring member including a sheet to cause the toner contained in the toner containing chamber to fly upward.

According to a first aspect of the present invention, there is provided a cartridge as specified in claims <NUM> to <NUM>. According to a second aspect of the present invention, there is provided an image forming apparatus as specified in claims <NUM> to <NUM>.

In the following description, an image forming apparatus and a process cartridge according to an embodiment of the present invention will be described with reference to the drawings.

First, the overall configuration of an electrophotographic image forming apparatus <NUM> will be described with reference to <FIG>. As illustrated in <FIG>, detachably mountable four process cartridges <NUM> (70Y, <NUM>, 70C, and <NUM>) are mounted using mounting members (not illustrated). Further, an upstream side and a downstream side in a direction in which the process cartridge <NUM> is mounted in the image forming apparatus <NUM> are defined to be a front-side surface side and a rear-side surface side, respectively.

Each of the process cartridges <NUM> includes an electrographic photosensitive drum (hereinafter referred to as a photosensitive drum) <NUM> (1a, 1b, 1c, 1d) and a development roller <NUM> (25a, 25b, 25c, 25d). Each of the process cartridges <NUM> further includes a process unit such as a charging roller <NUM> (2a, 2b, 2c, 2d) and a cleaning member <NUM> (6a, 6b, 6c, 6d). The charging roller <NUM> functions to evenly charge the surface of the photosensitive drum <NUM>, and the development roller <NUM> functions to develop a latent image formed on the photosensitive drum <NUM> with toner to visualize it. Then, the cleaning member <NUM> functions to remove toner remaining on the photosensitive drum <NUM> after the toner image formed on the photosensitive drum <NUM> is transferred onto a recording medium.

Further, a scanner unit <NUM>, which is used to selectively expose the photosensitive drum <NUM> based on image information to form the latent image on the photosensitive drum <NUM>, is provided below the process cartridges <NUM>.

A cassette <NUM>, which contains a recording medium S, is mounted at a lower portion of the apparatus main body 100A. Then, a recording medium conveyance unit is provided in such a manner that the recording medium S passes through a secondary transfer roller <NUM> and a fixing unit <NUM>, and then is conveyed to above the apparatus main body 100A. Further, an intermediate transfer unit <NUM>, which serves as an intermediate transfer unit for transferring the toner image formed on each of the photosensitive drums <NUM> (1a, 1b, 1c, and 1d), is provided above the process cartridges <NUM> (70Y, <NUM>, 70C, and <NUM>). The intermediate transfer unit <NUM> includes primary transfer rollers <NUM> (58a, 58b, 58c, and 58d) at positions facing the photosensitive drums <NUM> for the respective colors, and a facing roller <NUM> at a position facing the secondary transfer roller <NUM>, and a transfer belt <NUM> is hung across the primary transfer rollers <NUM> and the facing roller <NUM>. The transfer belt <NUM> circulates and moves so as to face and contact all of the photosensitive drums <NUM>, and the toner images are primarily transferred from the photosensitive drums <NUM> onto the transfer belt <NUM> by application of voltages to the primary transfer rollers <NUM> (58a, 58b, 58c, and 58d). Then, the toner on the transfer belt <NUM> is transferred onto the recording medium S by application of a voltage to the facing roller <NUM> disposed inside the transfer belt <NUM> and the secondary transfer roller <NUM>.

At the time of image formation, each of the photosensitive drums <NUM> is rotated, and the photosensitive drum <NUM> evenly charged by the charging roller <NUM> is selectively exposed by the scanner unit <NUM>. By this operation, the electrostatic latent image is formed on the photosensitive drum <NUM>. This latent image is developed by the development roller <NUM>. By this development, a toner image of each color is formed on each of the photosensitive drums <NUM>. In synchronization with this image formation, a pair of registration rollers <NUM> conveys the recording medium S to a secondary transfer position at which the facing roller <NUM> and the secondary transfer roller <NUM> are in abutment with each other via the transfer belt <NUM> interposed therebetween. Then, the toner image of each color on the transfer belt <NUM> is secondarily transferred onto the recording medium S by application of a transfer bias voltage to the secondary transfer roller <NUM>. By this operation, a color image is formed on the recording medium S. The recording medium S with the color image formed thereon is heated and pressed by the fixing unit <NUM>, by which the toner image is fixed thereto. After that, the recording medium S is discharged onto a discharge unit <NUM> by a discharge roller <NUM>. The fixing unit <NUM> is disposed at an upper portion of the apparatus main body 100A.

First to fourth toner cartridges <NUM> are each arranged side by side in the horizontal direction below the process cartridges <NUM> in the order corresponding to the colors of the toner contained in the respective process cartridges <NUM>. More specifically, the first toner cartridge 9Y contains yellow (Y) toner. Similarly, the second toner cartridge <NUM> contains magenta (M) toner and the third toner cartridge 9C contains cyan (C) toner. The fourth toner cartridge <NUM> contains black (K) toner. Then, each of the toner cartridges <NUM> replenishes the toner into the process cartridge <NUM> containing the toner of the same color.

The replenishment operation by the toner cartridge <NUM> is performed when a remaining amount detection unit (not illustrated) provided in the apparatus main body of the image forming apparatus <NUM> detects insufficiency of the toner remaining amount in the process cartridge <NUM>. The toner cartridge <NUM> is detachably mountable in the image forming apparatus <NUM> via a mounting unit such as a mounting guide (not illustrated) and a positioning member (not illustrated) provided in the image forming apparatus <NUM>. The details of the process cartridge <NUM> and the toner cartridge <NUM> will be described below.

First to fourth toner conveyance devices <NUM> are arranged below the toner cartridges <NUM> in correspondence with the respective toner cartridges <NUM>. Each of the toner conveyance devices <NUM> conveys upward the toner received from each of the toner cartridges <NUM> to supply it to each of development units <NUM>.

The process cartridge <NUM> (a development cartridge) according to the present embodiment will be described with reference to <FIG> is a main cross-sectional view of the process cartridge <NUM> containing the toner. The cartridge 70Y containing the yellow toner, the cartridge <NUM> containing the magenta toner, the cartridge 70C containing the cyan toner, and the cartridge <NUM> containing the black toner are configured similarly to one another.

The process cartridge <NUM> (70Y, <NUM>, 70C, <NUM>) includes a cleaning unit <NUM> (26a, 26b, 26c, 26d) and the development unit <NUM> (4a, 4b, 4c, 4d). The cleaning unit <NUM> includes the photosensitive drum <NUM> (1a, 1b, 1c, 1d), the charging roller <NUM> (2a, 2b, 2c, 2d), and the cleaning member <NUM> (6a, 6b, 6c, 6d). The development unit <NUM> includes the development roller <NUM>.

The charging roller <NUM> and the cleaning member <NUM> are disposed on the circumference of the photosensitive drum <NUM> as described above. The cleaning member <NUM> includes an elastic member <NUM> made of a rubber blade and a cleaning support member <NUM>. A distal end portion 7a of the rubber blade <NUM> is arranged in abutment with the photosensitive drum <NUM> from a counter direction to the rotational direction of the photosensitive drum <NUM>. The residual toner removed from the surface of the photosensitive drum <NUM> by the cleaning member <NUM> drops down into a removed toner chamber 27a. Further, a scooping sheet (not illustrated) for preventing a leak of the removed toner in the removed toner chamber 27a is in abutment with the photosensitive drum <NUM>. The photosensitive drum <NUM> is rotationally driven according to the image forming operation by transmitting a driving force of a main body driving motor (not illustrated) serving as a driving source to the cleaning unit <NUM>. The charging roller <NUM> is rotatably attached to the cleaning unit <NUM> via a charging roller bearing <NUM>, and is pressed toward the photosensitive drum <NUM> by a charging roller pressing member (not illustrated) and rotates by being driven by the photosensitive drum <NUM>.

As illustrated in <FIG> and <FIG>, the development unit <NUM> includes the development roller <NUM>, which rotates in contact with the photosensitive drum <NUM>, and a development frame member <NUM>, which supports the development roller <NUM>. The development frame member <NUM> includes a development chamber 31b, in which the development roller <NUM> is disposed.

As illustrated in <FIG>, the development roller <NUM> is rotatably supported on the development frame member <NUM> via a development front bearing <NUM> and a development rear bearing <NUM> attached on the both sides of the development frame member <NUM>, respectively. Further, a toner supply roller <NUM>, which rotates in a direction indicated by an arrow C in contact with the development roller <NUM>, and a development blade <NUM>, which is used to regulate the toner layer on the development roller <NUM>, are provided in the development chamber 31b.

When the toner supplied from the toner supply roller <NUM> to the development roller <NUM> passes through the development blade <NUM>, the toner coating amount on the development roller <NUM> is regulated and the toner is also charged. As a result, a toner coating is created optimally to develop the latent image formed on the photosensitive drum <NUM>.

The development roller <NUM> and the photosensitive drum <NUM> each rotate in such a manner that their surfaces move in the same direction as each other (the direction from the bottom to the top in the present embodiment) at a portion where they face each other (a portion where they contact each other). In the present embodiment, in reaction to a predetermined direct-current (DC) bias applied to the development roller <NUM>, the toner negatively charged with the aid of triboelectric charging is transferred only to a bright potential portion due to a potential difference therebetween and visualizes the electrostatic latent image at a development portion in contact with the photosensitive drum <NUM>.

As illustrated in <FIG>, the development frame member <NUM> includes a toner containing chamber 31a (a developer containing chamber), which is provided below the development chamber 31b and contains the toner, and an opening portion 31c (a first opening portion), which establishes communication between the development chamber 31b and the toner containing chamber 31a. A toner conveyance member <NUM> (a stirring member), which is used to stir the toner contained in the toner containing chamber 31a and also convey the toner to the development chamber 31b (the toner supply roller <NUM>), is provided in the toner containing chamber 31a.

The toner conveyance member <NUM> includes a stirring shaft 36a, which extends in the direction of the rotational axis of the development roller <NUM>, and a sheet member 36b (a sheet), which is fixed to the stirring shaft 36a so as to rotate together with the stirring shaft 36a. The sheet member 36b is configured to be able to be elastically deformed by receiving a force from outside. The sheet member 36b is a flexible sheet. The driving force is input to the development unit <NUM> as a result of engagement of an Oldham coupling <NUM> (a driving force reception member), which is provided at a longitudinal end portion of the toner supply roller <NUM> illustrated in <FIG>, with a main body development coupling (not illustrated) of the apparatus main body 100A. The development unit <NUM> is configured in such a manner that this driving force is transmitted to a drive train (a driving transmission member) of the development unit <NUM> and the toner conveyance member <NUM> rotates thereby.

Next, the overall configuration of the toner cartridge <NUM> mounted in the image forming apparatus <NUM> according to the present embodiment will be described with reference to <FIG> is a cross-sectional view of the toner cartridge (9Y, <NUM>, 9C) according to the present embodiment at the central portion in the longitudinal direction (the front-rear direction). <FIG> is a cross-sectional view of the toner cartridge (9Y, <NUM>, 9C) according to the present embodiment at a replenishment frame member opening <NUM> on the rear side in the longitudinal direction (the front-rear direction). <FIG> is a cross-sectional view of the toner cartridge (<NUM>) according to the present embodiment at the central portion in the longitudinal direction (the front-rear direction). <FIG> is a cross-sectional view of the toner cartridge (<NUM>) according to the present embodiment at the replenishment frame member opening <NUM> on the rear side in the longitudinal direction (the front-rear direction). <FIG> is a perspective view of the toner cartridge (9Y, <NUM>, 9C) according to the present embodiment as viewed from behind. <FIG> is a perspective view of the toner cartridge (9Y, <NUM>, 9C) according to the present embodiment with a side cover <NUM> removed as viewed from behind.

The toner cartridge <NUM> includes a replenishment frame member <NUM>, which supports various kinds of members in the toner cartridge <NUM>, and a replenishment toner containing chamber <NUM>, which contains the toner therein. Further, the replenishment frame member opening <NUM> is provided on the lower side in the orientation when the toner cartridge <NUM> is in normal use (the orientation in use). A replenishment toner stirring member <NUM>, a replenishment toner conveyance screw <NUM>, and a partition member <NUM> are provided in the replenishment toner containing chamber <NUM>. In the present embodiment, the fourth toner cartridge (<NUM>), which contains the black toner, is configured to be larger in the width direction (the right-left direction) compared to the first to third toner cartridges (9Y, <NUM>, and 9C), which contain the color toner.

The replenishment toner stirring member <NUM> is disposed in parallel with the longitudinal direction of the toner cartridge <NUM>, and is rotatably supported on the replenishment frame member <NUM>. Further, the replenishment toner stirring member <NUM> includes a rotational shaft 53a and a replenishment stirring sheet 53b as a conveyance member, which is a flexible sheet. One end of the replenishment stirring sheet 53b is attached to the rotational shaft 53a, and the other end of the replenishment stirring sheet 53b is configured as a free end. The rotational shaft 53a rotates and the replenishment stirring sheet 53b rotates in a direction indicated by an arrow G, by which the toner is stirred by the replenishment stirring sheet 53b and is conveyed to the replenishment toner conveyance screw <NUM>.

The replenishment toner conveyance screw <NUM> is disposed in parallel with the rotational axis of the replenishment toner stirring member <NUM>, and is rotatably supported on the replenishment frame member <NUM>. The replenishment toner conveyance screw <NUM> conveys the toner in the replenishment toner containing chamber <NUM> from the front side to the rear side (from the upstream side to the downstream side in the direction in which the toner cartridge <NUM> is mounted) by rotating. In other words, the replenishment toner conveyance screw <NUM> conveys the toner toward the replenishment frame member opening <NUM>.

The partition member <NUM> forms a tunnel portion <NUM> together with the replenishment frame member <NUM>. The tunnel portion <NUM> is formed in correspondence with the outer diameter of the replenishment toner conveyance screw <NUM>, and plays a role of conveying a fixed amount by scraping off the toner conveyed by the replenishment toner conveyance screw <NUM>. Further, similarly, the partition member <NUM> forms a toner discharge chamber <NUM> together with the replenishment frame member <NUM>.

The replenishment frame member opening <NUM> is provided at the toner discharge chamber <NUM>. Further, a pump <NUM>, which includes an extensible/compressible bellows portion 65a, is provided in communication with the inside. The pump <NUM> is extended/compressed by a drive train, which will be described below, and can change the inner volume thereof. The extension/compression of the pump <NUM> causes the inner pressures in the replenishment toner containing chamber <NUM> and the toner discharge chamber <NUM> to be changed and air to be supplied and exhausted into and from the replenishment frame member opening <NUM>, thereby allowing the toner to be stably discharged.

The drive train is disposed behind the toner cartridge <NUM>. A driving input gear <NUM> receives rotational driving from the image forming apparatus <NUM> and transmits the rotation to a cam gear <NUM>. A cam groove 60a is provided on the cam gear <NUM>, and a link protrusion portion 61a of a link mechanism <NUM> is engaged with the cam groove 60a. The link mechanism <NUM> is supported on the side cover <NUM> movably in the front-rear direction. The rotation of the cam gear <NUM> causes the cam link portion 61a to pass through the ridge portion and the bottom portion of the cam groove 60a alternately, thereby causing the link mechanism <NUM> to reciprocate in the front-rear direction. The link mechanism <NUM> is coupled with a coupling portion 65b of the pump <NUM>, and the coupling portion 65b of the pump <NUM> reciprocates according to the movement of the link mechanism <NUM>. Then, the bellows portion 65a of the pump <NUM> is extended/compressed, which causes a change in the inner volume in the pump <NUM>, thereby causing changes in the inner pressures in the replenishment toner containing chamber <NUM> and the toner discharge chamber <NUM> as a result thereof. Next, a screw gear <NUM> is provided at an end portion of the above-described replenishment toner conveyance screw <NUM>, and the screw gear <NUM> receives rotational driving from the cam gear <NUM> and rotates the replenishment toner conveyance screw <NUM>.

Further, at the toner discharge chamber <NUM> on the bottom surface thereof in the orientation when the toner cartridge <NUM> is in normal use (the orientation in use), the replenishment frame member opening <NUM> is provided, and a replenishment port shutter <NUM> including a replenishment port <NUM> is supported on the replenishment frame member <NUM> movably in the front-rear direction. The replenishment frame member opening <NUM> is closed by the replenishment port shutter <NUM> when the toner cartridge <NUM> is not mounted in the image forming apparatus <NUM>. The replenishment port shutter <NUM> is configured to be biased by the image forming apparatus <NUM> and moved to a predetermined position in conjunction with the operation for mounting the toner cartridge <NUM>. When the replenishment port shutter <NUM> is mounted in the image forming apparatus <NUM>, the replenishment frame member opening <NUM> and the replenishment port <NUM> are brought into communication with each other, thereby allowing the toner to be discharged from the toner cartridge <NUM>.

Next, a toner replenishment operation according to the present embodiment will be described.

As illustrated in <FIG>, a toner reception port <NUM> is provided on the development unit <NUM> at one end (a longitudinal end portion) thereof on the downstream side in the direction in which the process cartridge <NUM> is mounted, and a reception conveyance path <NUM> is provided in communication with the toner reception port <NUM>. The toner discharged from the toner cartridge <NUM> is supplied to the toner reception port <NUM> by the toner conveyance device <NUM> installed in the apparatus main body 100A.

As illustrated in <FIG>, a reception conveyance screw <NUM> (a conveyance member) is disposed inside the reception conveyance path <NUM>. The reception conveyance path <NUM> extends in the direction of the rotational axis of the development roller <NUM> (the longitudinal direction). The reception conveyance screw <NUM> includes a shaft portion and a helical blade portion provided on the outer periphery of the shaft portion, and is configured to convey the toner by rotating. Further, as illustrated in <FIG>, a rotational axis (Ra2) of the reception conveyance screw <NUM> (the conveyance member) is located on the lower side with respect to a rotational axis (Ra1) of the toner conveyance member <NUM> with the process cartridge <NUM> mounted in the apparatus main body 100A.

The toner containing chamber 31a includes a containing chamber communication port <NUM> (a second opening portion) for receiving the toner received from the toner reception port <NUM> and conveyed through in the reception conveyance path <NUM> by the reception conveyance screw <NUM> into the toner containing chamber 31a. The containing chamber communication port <NUM> is provided at the longitudinally central portion of the development unit <NUM> (the toner containing chamber 31a), and establishes communication between the reception conveyance path <NUM> and the toner containing chamber 31a. The containing chamber communication port <NUM> is located on the lower side with respect to the rotational axis (Ra1) of the toner conveyance member <NUM> with the process cartridge <NUM> mounted in the apparatus main body 100A. The containing chamber communication port <NUM> is provided at such a position that the sheet member 36b of the toner conveyance member <NUM> passes through the front side thereof when rotating. The sheet member 36b passes through the front side of the containing chamber communication port <NUM> so as to close the containing chamber communication port <NUM>.

Next, the toner conveyance configuration in the development unit <NUM> will be described in detail with reference to <FIG> and <FIG>. Directions such as upward, downward, vertical, and horizontal directions regarding the members and the like in the development unit <NUM> refer to the directions in the orientation of the development unit <NUM> with the process cartridge <NUM> mounted in the apparatus main body 100A and the image forming apparatus <NUM> ready to form an image.

The reception conveyance screw <NUM> provided in the development unit <NUM> extends in the direction of the rotational axis of the development roller <NUM>, and conveys the toner received from the toner reception port <NUM> into the toner containing chamber 31a via the containing chamber communication port <NUM>.

The inner wall of the toner containing chamber 31a includes a deformation portion 31a1 (a first portion) in abutment with the sheet member 36b below the opening portion 31c. The deformation portion 31a1 is provided in a region of the inner wall opposite of a region of the inner wall where the containing chamber communication port <NUM> of the toner containing chamber 31a is provided with respect to the rotational axis Ra1 in cross section perpendicular to the rotational axis Ra1 of the toner conveyance member <NUM>. The sheet member 36b of the toner conveyance member <NUM> is elastically deformed (deflected) by abutting against the deformation portion 31a1 and receiving a force from the deformation portion 31a1 when the toner conveyance member <NUM> rotates. Further, the toner conveyance member <NUM> rotates with the sheet member 36b in contact with the deformation portion 31a1, thereby rotating with the toner borne on the surface of the sheet member 36b on the downstream side in the rotational direction thereof and conveying the toner in the rotational direction of the toner conveyance member <NUM> while stirring the toner. In the present embodiment, the deformation portion 31a1 refers to a portion of the inner wall of the toner containing chamber 31a as far as a position at which the sheet member 36b separates therefrom, as illustrated in <FIG>. Further, the inner wall of the toner containing chamber 31a includes a restoration portion 31a2 (a second portion) on the downstream side of the deformation portion 31a1 and the upstream side of the opening portion 31c in the rotational direction of the toner conveyance member <NUM>. The restoration portion 31a2 is provided in the region of the inner wall opposite of the region of the inner wall where the containing chamber communication port <NUM> of the toner containing chamber 31a is provided with respect to the rotational axis Ra1 in cross section perpendicular to the rotational axis Ra1 of the toner conveyance member <NUM>.

Now, the restoration portion 31a2 is a portion for restoring (resolving) at least a part of the elastic deformation (the deflection) due to the contact of the sheet member 36b with the inner wall of the toner containing chamber 31a. In the present embodiment, the restoration portion 31a2 is arranged on the upper side with respect to the horizontal surface passing through the rotational axis (Ra1) of the toner conveyance member <NUM>. Therefore, after the sheet member 36b passes through the deformation portion 31a1 according to the rotation of the toner conveyance member <NUM>, the contact state of the sheet member 36b with the inner wall is resolved at the restoration portion 31a2. As a result, the elastic deformation of the sheet member 36b caused by the deformation portion 31a1 is restored into a natural state with the aid of its own elastic resilient force. The toner borne on the sheet member 36b is caused to fly (jumped up) against the gravitational force and is projected toward the opening portion 31c according to the geometry change due to this restoration of the sheet member 36b. The inner wall of the toner containing chamber 31a is shaped so as to contact with and separate from the sheet member 36b in this manner. The opening portion 31c of the inner wall is located on the downstream side of the restoration portion 31a2 in the rotational direction of the toner conveyance member <NUM>. The toner flying toward the opening portion 31c is partially supplied into the development chamber 31b. On the other hand, toner failing to reach the inside of the development chamber 31b drops down into the toner containing chamber 31a and returns to the bottom portion of the toner containing chamber 31a. The toner is stirred and conveyed by repeating this cycle.

In the case where the containing chamber communication port <NUM> is disposed at the toner containing chamber 31a in the configuration that supplies the toner from the toner containing chamber 31a to the development chamber 31b by utilizing the rotational driving of the toner conveyance member <NUM>, the following possibility arises.

Toner located near the containing chamber communication port <NUM> is pushed by the sheet member 36b if the reception conveyance screw <NUM> is not kept driven at the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>. One possible consequence thereof is that the toner moves (flows backward) in the reception conveyance path <NUM> in the opposite direction from the direction in which the toner is conveyed by the reception conveyance screw <NUM>. Further, the toner flowing backward to the reception conveyance path <NUM> may be aggregated due to a pressure being applied to the toner when the sheet member 36b passes through the front side of the containing chamber communication port <NUM> so as to close the containing chamber communication port <NUM>. If the toner is aggregated in the reception conveyance path <NUM>, the toner may clog the inside of the reception conveyance path <NUM>, making it impossible to replenish a predetermined amount to the toner containing chamber 31a.

Therefore, the present embodiment is directed to preventing the toner clog in the containing chamber communication port <NUM>.

Next, the driving transmission configuration of the development unit <NUM> according to an example <NUM> will be described with reference to <FIG> and <FIG>.

The example <NUM> is configured in such a manner that the driving of the toner conveyance member <NUM> and the driving of the reception conveyance screw <NUM> can be controlled independently of each other.

<FIG> is a block diagram illustrating the circuit configuration of the driving control, which is provided in the image forming apparatus <NUM> illustrated in, for example, <FIG>. When the image formation or the replenishment operation is performed, a driving signal is transmitted from a driving control unit <NUM> illustrated in <FIG> to a development unit driving motor <NUM> (a first driving source) and a reception conveyance screw driving motor <NUM> (a second driving source), which are driving sources of the apparatus main body 100A.

The driving force output from the development unit driving motor <NUM> is transmitted to the main body development coupling (not illustrated) of the apparatus main body 100A. Then, the driving force is input from the apparatus main body 100A to the development unit <NUM> by the engagement of the Oldham coupling <NUM> (the driving force reception member), which is provided at the longitudinal end portion of the toner supply roller <NUM>, with the main body development coupling (not illustrated). This driving force is transmitted to the gear train provided in the development unit <NUM>, and the driving force is transmitted to a conveyance member gear <NUM> (a second gear). The conveyance member gear <NUM> is provided at a longitudinal end portion of the toner conveyance member <NUM> so as to rotate together with the toner conveyance member <NUM>.

The driving force output from the reception conveyance screw driving motor <NUM> is transmitted from a reception conveyance screw main body gear (not illustrated) of the apparatus main body 100A to a conveyance screw gear <NUM> (a third gear). The conveyance screw gear <NUM> is provided at a longitudinal end portion of the reception conveyance screw <NUM> so as to rotate together with the reception conveyance screw <NUM>.

Now, the drive gear train provided in the development unit <NUM> will be described in detail with reference to <FIG>. As illustrated in <FIG>, a toner supply roller gear <NUM> (a first gear) is provided at a second end portion, which is the longitudinal end portion of the toner supply roller <NUM> opposite from a first end portion at which the Oldham coupling <NUM> is provided. A development roller gear <NUM> is provided at the longitudinal shaft portion of the development roller <NUM> on the same side as the toner supply roller gear <NUM>. The driving force input to the Oldham coupling <NUM> is transmitted from the toner supply roller gear <NUM> to the development roller gear <NUM> via a development idler gear <NUM>, by which the development roller <NUM> is rotated.

The above-described conveyance member gear <NUM> is provided at the longitudinal end portion of the toner conveyance member <NUM> on the same side as the toner supply roller gear <NUM>. A conveyance member idler gear <NUM> is meshed with both the development idler gear <NUM> and the conveyance member gear <NUM>, and transmits the driving force from the development idler gear <NUM> to the conveyance member gear <NUM>. In this manner, the driving force input to the Oldham coupling <NUM> of the toner supply roller <NUM> is transmitted to the toner supply roller gear <NUM>, the development idler gear <NUM>, the conveyance member idler gear <NUM>, and the conveyance member gear <NUM> sequentially in this order.

The gear train such as the toner supply roller gear <NUM> is provided on the axially opposite side (the other end side) from the driving force input unit of the development unit <NUM> in light of the space and the like in the present embodiment, but the above-described gear train and the driving force input unit may be provided on the same side.

The driving control of the toner conveyance member <NUM> and the reception conveyance screw <NUM> according to the present example will be described with reference to <FIG> and <FIG>.

<FIG> is a sequence chart illustrating driving control in a case where the toner conveyance member <NUM> and the reception conveyance screw <NUM> are driven substantially at the same time. First, in step S <NUM>, a print signal is transmitted to the image forming apparatus <NUM>. Then, in step S102, a replenishment necessity/unnecessity determination device (not illustrated) determines whether the replenishment is necessary. If the replenishment is necessary (YES in step S <NUM>), in step S <NUM>, the replenishment operation, the toner conveyance member <NUM>, and the reception conveyance screw <NUM> start being driven substantially at the same time. If the replenishment is unnecessary (NO in step S102), in step S104, the toner conveyance member <NUM> and the reception conveyance screw <NUM> start being driven substantially at the same time without the replenishment operation started. In step S <NUM>, the image forming operation is started after the driving is started. In step S <NUM>, the image forming operation is ended. After that, in step S107, the replenishment operation, the toner conveyance member <NUM>, and the reception conveyance screw <NUM> are stopped substantially at the same time.

<FIG> is a sequence chart illustrating driving control in a case where the toner conveyance member <NUM> and the reception conveyance screw <NUM> are driven at different timings. First, in step S201, the print signal is transmitted to the image forming apparatus <NUM>. Then, in step S202, the replenishment necessity/unnecessity determination device (not illustrated) determines whether the replenishment is necessary. If the replenishment is necessary (YES in step S202), in step S203, the replenishment operation and the reception conveyance screw <NUM> start being driven substantially at the same time. If the replenishment is unnecessary (NO in step S202), in step S204, the reception conveyance screw <NUM> starts being driven without the replenishment operation started. After the reception conveyance screw <NUM> starts being driven, in step S205, the toner conveyance member <NUM> starts being driven. In step S206, the image forming operation is started at the same time as the start of the driving of the toner conveyance member <NUM>. In step S207, the image forming operation is ended. After that, in step S208, the toner conveyance member <NUM> is stopped. After the operation of the toner conveyance member <NUM> is stopped, in step S209, the replenishment operation and the reception conveyance screw <NUM> are stopped at the same time.

In this manner, the reception conveyance screw <NUM> is kept in a driven state when the toner conveyance member <NUM> is driven. More specifically, the image forming apparatus <NUM> can prevent the toner clog in the containing chamber communication port <NUM> that otherwise might occur due to the backward flow of the toner into the reception conveyance path <NUM>, by keeping the reception conveyance screw <NUM> in the driven state at the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>. Further, the image forming apparatus <NUM> can prevent occurrence of a failure in the toner supply from the toner cartridge <NUM>.

The reception conveyance screw <NUM> does not have to be kept driven at timings other than the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>. That is, the intended advantageous effects can be achieved as long as the reception conveyance screw <NUM> is in the driven state at the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>.

The following experiment was conducted to verify the advantageous effects of the present example. A two-sheet intermittent printing endurance test was conducted under an environment of normal-temperature and normal-humidity conditions (the temperature was <NUM> and the humidity was <NUM>%). In this printing endurance, horizontal lines at an image ratio of <NUM>% were printed. The present experiment started with toner of <NUM> loaded in the process cartridge <NUM>, and control was performed such that toner of <NUM> is replenished from the toner cartridge <NUM> every time the toner is reduced by <NUM>. Then, the printing endurance continued until the consumed amount of the process cartridge <NUM> reached <NUM>%, and an evaluation was made regarding whether the toner clog had occurred in the reception conveyance path <NUM> and the replenishment failure had occurred.

The following three types of driving control were performed as comparison examples. In a comparison example <NUM>, when the print signal was transmitted, the toner conveyance member <NUM> was driven, and the reception conveyance screw <NUM> was driven after that. The reception conveyance screw <NUM> was stopped, and the toner conveyance member <NUM> was stopped after that. In a comparison example <NUM>, when the print signal was transmitted, the toner conveyance member <NUM> was driven, and the reception conveyance screw <NUM> was driven after that. The toner conveyance member <NUM> was stopped, and the reception conveyance screw <NUM> was stopped after that. In a comparison example <NUM>, when the print signal was transmitted, the reception conveyance screw <NUM> was driven, and the toner conveyance member <NUM> was driven after that. The reception conveyance screw <NUM> was stopped, and the toner conveyance member <NUM> was stopped after that.

After the above-described two-sheet intermittent printing endurance test, a pass or a fail was determined based on whether the toner clog had occurred in the reception conveyance path <NUM>. If the toner clog had not occurred, the result was evaluated as a pass.

<FIG> illustrates the respective timing charts and evaluation results of the present example and the comparison examples <NUM>, <NUM>, and <NUM>.

The control according to the present example was able to prevent the toner from flowing backward into the reception conveyance path <NUM> and being aggregated in the reception conveyance path <NUM> by keeping the reception conveyance screw <NUM> in a rotating state when the toner conveyance member <NUM> was rotating. As a result, the toner clog was able to be prevented.

In the control according to the comparison example <NUM>, the reception conveyance screw <NUM> was driven after the toner conveyance member <NUM> was driven. Further, the toner conveyance member <NUM> was stopped after the reception conveyance screw <NUM> was stopped. Therefore, the toner flowed backward into the reception conveyance path <NUM> and was aggregated in the reception conveyance path <NUM>. As a result, the toner clog had occurred.

In the control according to the comparison example <NUM>, the reception conveyance screw <NUM> was driven after the toner conveyance member <NUM> was driven, and therefore the toner flowed backward into the reception conveyance path <NUM> and was aggregated in the reception conveyance path <NUM>. As a result, the toner clog had occurred.

In the control according to the comparison example <NUM>, the toner conveyance member <NUM> was stopped after the reception conveyance screw <NUM> was stopped, and therefore the toner flowed backward into the reception conveyance path <NUM> and was aggregated in the reception conveyance path <NUM>. As a result, the toner clog had occurred.

According to the above-described evaluation result, in the present example, the reception conveyance screw <NUM> is in the driven state at the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>. As a result, the present example can prevent the toner clog in the containing chamber communication port <NUM> that otherwise might occur due to the backward flow of the toner into the reception conveyance path <NUM>. Further, the present example can prevent the occurrence of the failure in the toner supply from the toner cartridge <NUM>.

The image forming apparatus <NUM> is configured to include two motors, i.e., the motor for driving the reception conveyance screw <NUM> and the motor for driving the toner conveyance member <NUM> in the present example, but is not limited thereto. A modification using a single development unit driving motor <NUM> and an actuator <NUM> will be described.

<FIG> illustrates a block diagram of a driving transmission route according to the modification. The present modification is configured in such a manner that the conveyance screw gear <NUM> is always driven when the development unit driving motor <NUM> is driven, and is configured in such a manner that the driving is transmitted from the development unit driving motor <NUM> to the Oldham coupling <NUM> via the actuator <NUM>. The actuator <NUM> is made of an electromagnetic clutch or a spring clutch. The actuator <NUM> can be switched to a first state, in which the driving force can be transmitted from the development unit driving motor <NUM> to the Oldham coupling <NUM>, and a second state, in which the transmission of the driving force from the development unit driving motor <NUM> to the Oldham coupling <NUM> is blocked. In the second state, the conveyance member gear <NUM> is not driven and therefore the rotation of the toner conveyance member <NUM> is stopped. The driving control unit <NUM> can carry out a first mode of driving the reception conveyance screw <NUM> while rotating the conveyance member <NUM> by switching the actuator <NUM> into the first state, and a second mode of driving the reception conveyance screw <NUM> with the actuator <NUM> switched in the second state. In both the first mode and the second mode, the toner aggregation and the toner clog in the reception conveyance path <NUM> are less likely to occur.

An example <NUM> is different from the example <NUM> in that the example <NUM> includes only a single driving input unit for driving the toner conveyance member <NUM> and the reception conveyance screw <NUM>.

The driving transmission configuration of the development unit <NUM> will be described with reference to <FIG> and <FIG>.

<FIG> is a block diagram illustrating the circuit configuration of driving control, which is provided in the image forming apparatus <NUM> illustrated in, for example, <FIG>. When the image formation or the replenishment operation is performed, the driving signal is transmitted from the driving control unit <NUM> illustrated in <FIG> to the development unit driving motor <NUM>, which is the driving source of the apparatus main body 100A. The Oldham coupling <NUM> (the driving force reception member) provided at the first end portion, which is the longitudinal end portion of the toner supply roller <NUM>, is engaged with the main body development coupling (not illustrated) of the apparatus main body 100A. Due to this configuration, the driving force output from the development unit driving motor <NUM> is input to the development unit <NUM>. The Oldham coupling <NUM> is configured to receive the driving force for driving the development unit <NUM> from the apparatus main body 100A.

Now, the driving configuration of the development unit <NUM> will be described in detail with reference to <FIG>. The toner supply roller gear <NUM> (the first gear) is provided at the second end portion of the toner supply roller <NUM> longitudinally opposite from the first end portion. The development roller gear <NUM> is provided at the longitudinal end portion of the development roller <NUM> on the same side as the second end portion of the toner supply roller <NUM>. The development idler gear <NUM>, which is meshed with both the toner supply roller gear <NUM> and the development roller gear <NUM>, is provided. The driving force input from the Oldham coupling <NUM> at the first end portion of the toner supply roller <NUM> is transmitted to the development roller gear <NUM> via the toner supply roller gear <NUM> and the development idler gear <NUM>, and the development roller <NUM> is rotationally driven thereby.

The development unit <NUM> further includes the conveyance member gear <NUM> (the second gear), the conveyance screw gear <NUM> (the third gear), the conveyance member idler gear <NUM> (an intermediate gear), and a reception conveyance screw idler gear <NUM>.

The conveyance member gear <NUM> is fixed to the longitudinal end portion of the toner conveyance member <NUM> on the same side as the toner supply roller gear <NUM>, and rotates together with the toner conveyance member <NUM>. The conveyance screw gear <NUM> is fixed to the longitudinal end portion of the reception conveyance screw <NUM> on the same side as the toner supply roller gear <NUM>, and rotates together with the reception conveyance screw <NUM>. The conveyance member idler gear <NUM> is meshed with both the development idler gear <NUM> and the conveyance member gear <NUM>, and transmits the driving force from the development idler gear <NUM> to the conveyance member gear <NUM>. The reception conveyance screw idler gear <NUM> is meshed with both the conveyance member idler gear <NUM> and the conveyance screw gear <NUM>, and transmits the driving force from the reception conveyance member idler gear <NUM> to the conveyance screw gear <NUM>.

The driving force input to the Oldham coupling <NUM> of the toner supply roller <NUM> is transmitted to the toner supply roller gear <NUM>, the development idler gear <NUM>, the conveyance member idler gear <NUM>, and the conveyance member gear <NUM> sequentially in this order, and the toner conveyance member <NUM> is rotationally driven. Further, the driving force transmitted to the conveyance member idler gear <NUM> is transmitted to the conveyance screw gear <NUM> via the reception conveyance screw idler gear <NUM>, and the reception conveyance screw <NUM> is rotationally driven thereby.

As the configuration of the process cartridge <NUM>, the process cartridge <NUM> includes the Oldham coupling <NUM>, which receives the driving force from the apparatus main body 100A, and the driving force transmission unit configured to transmit the driving force from the Oldham coupling <NUM> to the toner conveyance member <NUM> and the reception conveyance screw <NUM>. The driving force transmission unit includes all the above-described gears for rotationally driving the toner conveyance member <NUM> and the reception conveyance screw <NUM>. This driving force transmission unit is configured in such a manner that, when the Oldham coupling <NUM> is rotated, the toner conveyance member <NUM> and the reception conveyance screw <NUM> are always rotated (always driven).

The operation timings of the toner conveyance member <NUM> and the reception conveyance screw <NUM> according to the present example will be described with reference to <FIG> and <FIG>.

The operation timings of the toner conveyance member <NUM> and the reception conveyance screw <NUM> according to the present example are controlled in a similar manner to the control described with reference to <FIG>. The toner conveyance member <NUM> and the reception conveyance screw <NUM> start being driven substantially at the same time, and stop being driven substantially at the same time. The reception conveyance screw <NUM> is always kept in the rotating state while the toner conveyance member <NUM> is rotating. More specifically, the toner clog in the containing chamber communication port <NUM> that otherwise might occur due to the backward flow of the toner into the reception conveyance path <NUM> can be prevented, by keeping the reception conveyance screw <NUM> in the driven state at the timing when the sheet member 36b of the toner conveyance member <NUM> passes through the front side of the containing chamber communication port <NUM>. Further, the image forming apparatus <NUM> can prevent the occurrence of the failure in the toner supply from the toner cartridge <NUM>.

The following experiment was conducted to verify the advantageous effects of the present example, similarly to the example <NUM>. A two-sheet intermittent printing endurance test was conducted under an environment of normal-temperature and normal-humidity conditions (the temperature was <NUM> and the humidity was <NUM>%). In this printing endurance, horizontal lines at an image ratio of <NUM>% were printed. The present experiment started with toner of <NUM> loaded in the process cartridge <NUM>, and control was performed such that toner of <NUM> is replenished from the toner cartridge <NUM> every time the toner is reduced by <NUM>. Then, the printing endurance continued until the consumed amount of the process cartridge <NUM> reached <NUM>%, and an evaluation was made regarding whether the toner clog had occurred in the reception conveyance path <NUM> and the replenishment failure had occurred.

Similarly to the example <NUM>(a), the toner clog in the containing chamber communication port <NUM> that otherwise might occur due to the backward flow of the toner into the reception conveyance path <NUM> can be prevented, by keeping the reception conveyance screw <NUM> in the rotating state when the toner conveyance member <NUM> is rotating. Further, the present example can prevent the occurrence of the failure in the toner supply from the toner cartridge <NUM>.

Claim 1:
A cartridge (<NUM>) detachably mountable to an apparatus main body (<NUM>) of an image forming apparatus, the cartridge comprising:
a development roller (<NUM>) configured to bear a developer thereon and to be rotatable about a rotational axis;
a frame member (<NUM>) including a development chamber (31b) in which the development roller (<NUM>) is provided, a developer containing chamber (31a) containing the developer and located below the development chamber (31b) in a state where the cartridge is mounted in the apparatus main body, and a first opening portion (31c) through which the development chamber and the developer containing chamber are in communication, the developer containing chamber (31a) including an inner wall; and
a stirring member (<NUM>) provided rotatably in the developer containing chamber and configured to stir the developer contained in the developer containing chamber (31a), the stirring member (<NUM>) including a stirring shaft (36a) extending in a direction of the rotational axis and a sheet (36b) attached to the stirring shaft so as to rotate together with the stirring shaft,
wherein the sheet (36b) of the stirring member (<NUM>) is configured to rotate in contact with the inner wall of the developer containing chamber (31a) in such a manner that, after the sheet is elastically deformed by contact with a portion of the inner wall, at least a part of the elastic deformation is restored, thereby projecting the developer on the sheet toward the first opening portion (31c),
characterized in that the frame member (<NUM>) includes a second opening portion (<NUM>) for receiving the developer replenished from an outside of the cartridge into the developer containing chamber (31a) and the cartridge further comprises a conveyance member (<NUM>) configured to be driven in such a manner that the developer is replenished into the developer containing chamber (31a) through the second opening portion (<NUM>),
wherein the second opening portion (<NUM>) of the developer containing chamber (31a) is disposed at a position in such a manner that the sheet (36b) passes through a front side thereof when the stirring member (<NUM>) is rotating, and
wherein the conveyance member (<NUM>) is configured to be kept driven at a timing when the sheet (36b) passes through the front side of the second opening portion (<NUM>) while the stirring member (<NUM>) is rotating.