Patent Description:
In a conventionally known configuration, a developing cartridge (including developing unit), a process cartridge (including developing unit and photosensitive drum), etc. is attachable to and detachable from (exchangeable) an apparatus main body of an electrophotographic image forming apparatus.

<CIT> discusses a configuration in which a developing unit is swingably attached to a drum unit, and the developing unit is pressed against the drum unit by using a pressing unit to bring the outer peripheral surface of a developing roller into stable contact with the outer peripheral surface of a photosensitive drum.

<CIT> discusses a process cartridge that includes a toner receiving opening for replenishment of a developing agent and can be replenished with toner from outside. The process cartridge discussed in <CIT> is provided with a sealing member including an elastic member at the toner receiving opening in order to prevent leakage of the toner in replenishment. <CIT> discloses a process cartridge for an image forming apparatus having a first unit including an image bearing member for bearing a development agent image and a second unit including a development agent bearing member and a coupling portion coupling the first and second units, and providing means for limiting rotation of the coupling portion during image formation.

The configuration in which the developing unit is pressed against the drum unit by the pressing unit as discussed in <CIT> may presumably further adopt a replenishing unit that includes the toner receiving opening and the sealing member for replenishment of the developing agent as discussed in <CIT>.

In such a case, when the sealing member provided at the receiving opening receives stress, the sealing member may be elastically deformed. The elastic deformation of the sealing member may change contact pressure between the outer peripheral surface of the developing roller and the outer peripheral surface of the photosensitive drum. This may make the contact state between the photosensitive drum and the developing roller unstable.

Thus, it is desired to provide a process cartridge, a developing apparatus, and an image forming apparatus that each enable replenishment of a developing agent and improve stability of a contact state between an image bearing member and a developing agent bearing member.

The present invention in an aspect provides a process cartridge as specified in claims <NUM> to <NUM>.

The present invention in another aspect provides a developing apparatus as specified in claims <NUM> and <NUM>.

The present invention in another aspect provides an image forming apparatus as specified in claim <NUM>.

An embodiment of the present invention can be implemented in a mode of an electrophotographic image forming apparatus (hereinafter, simply referred to as "image forming apparatus" in some cases), or any of a process cartridge and a developing apparatus configuring a part of the image forming apparatus.

An image forming apparatus according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

Embodiments described below describe the present invention for illustrative purpose, and dimensions, materials, shapes, relative positional relationship, etc. of components described below do not limit the scope of the present invention, unless otherwise specified.

Electrophotographic image forming apparatuses form an image on a recording medium by using an electrophotographic image forming system. Examples of electrophotographic image forming apparatuses include an electrophotographic copying apparatus, an electrophotographic printer (e.g., laser beam printer and light-emitting diode (LED) printer), a facsimile apparatus, and a word processor.

The developing apparatus used in the image forming apparatus includes at least a developing unit. The developing apparatus may be formed as a cartridge that is attachable to and detachable from a main body of the electrophotographic image forming apparatus. The developing apparatus may include a toner cartridge that is attachable to and detachable from a frame member of the developing apparatus and can replenish toner to the developing apparatus.

The process cartridge configuring a part of the image forming apparatus has a configuration in which a charging unit, and a developing unit or a cleaning unit, and an electrophotographic photosensitive drum are integrated into a cartridge, and the cartridge is attachable to and detachable from the main body of the electrophotographic image forming apparatus. Alternatively, the process cartridge may have a configuration in which at least one of the charging unit, the developing unit, and the cleaning unit is integrated with the electrophotographic photosensitive drum into a cartridge, and the cartridge is attachable to and detachable from the main body of the electrophotographic image forming apparatus. Yet alternatively, the process cartridge may have a configuration in which at least the developing unit is integrated with the electrophotographic photosensitive drum into a cartridge, and the cartridge is attachable to and detachable from the main body of the electrophotographic image forming apparatus. The process cartridge may be used while being fixed to the image forming apparatus.

First, an entire configuration of an image forming apparatus <NUM> according to the present embodiment will be described below with reference to <FIG>, <FIG>.

<FIG> is a conceptual sectional view of the image forming apparatus according to the embodiment of the present invention.

<FIG> is a conceptual sectional view of a process cartridge according to the embodiment of the present invention. <FIG> is a conceptual diagram illustrating a contact state (contact position) and a separated state (separated position) between a developing agent bearing member and an image bearing member.

In <FIG>, a section in a vertical direction of the image forming apparatus <NUM>, the process cartridges <NUM>, and the toner cartridges <NUM> according to the present embodiment in use is illustrated. In <FIG>, a cross-section orthogonal to a longitudinal direction of one process cartridge <NUM> is illustrated.

In the present embodiment, the process cartridges <NUM> and the toner cartridges <NUM> are flexibly attachable and detachable from the main body of the image forming apparatus <NUM>. An attachment and detachment direction is a direction along the longitudinal direction of each of the process cartridges or the toner cartridges.

In the present embodiment, configurations and operations of first to fourth image forming units are substantially the same except that the colors of images to be formed are different from one another. Accordingly, in the following description, when there is no need to distinguish the first to fourth image forming units, the first to fourth image forming units are collectively described while subscripts Y to K are omitted.

First to fourth process cartridges <NUM> are arranged in a horizontal direction. Each of the process cartridges <NUM> includes a cleaning unit <NUM> (first unit) and a developing unit <NUM> (second unit). The cleaning unit <NUM> includes a photosensitive drum <NUM> serving as an image bearing member, a charging roller <NUM> serving as a charging means that uniformly charges the surface of the photosensitive drum <NUM>, and a cleaning blade <NUM> serving as a cleaning means. The developing unit <NUM> includes developing means that contains a developing roller <NUM> (developing agent bearing member) and a developing agent T (hereinafter, toner), and develops an electrostatic latent image on the photosensitive drum <NUM>. The cleaning unit <NUM> and the developing unit <NUM> are swingably supported by each other. The first to fourth process cartridges <NUM> (Y, M, C, and K) each contains yellow (Y), magenta (M), cyan (C), or black (K) toner in the respective developing unit <NUM>.

Each of the process cartridges <NUM> is attachable to and detachable from the image forming apparatus <NUM> through an attachment unit provided, such as an attachment guide (not illustrated) and a positioning member (not illustrated), in the image forming apparatus <NUM>. A scanner unit <NUM> for forming an electrostatic latent image is disposed below the process cartridges <NUM>. A waste toner conveyance unit <NUM> is disposed on a back side of the process cartridge <NUM> (downstream side in attachment and detachment direction of process cartridges <NUM>) in the image forming apparatus <NUM>.

First to fourth toner cartridges <NUM> are arranged in the horizontal direction below the process cartridges <NUM> in the order corresponding to colors of the toner contained in the respective process cartridges <NUM>. In other words, the first to fourth toner cartridges <NUM> (Y, M, C, and K) respectively contain yellow (Y) toner, magenta (M) toner, cyan (C) toner, and black (K) toner. Further, each of the toner cartridges <NUM> replenishes the toner to the process cartridge <NUM> containing the toner with the same color.

The replenishing operation by each of the toner cartridges <NUM> is performed when a residual amount detection unit (not illustrated) provided in the main body of the image forming apparatus <NUM> detects a shortage of a residual amount of the toner in the corresponding process cartridge <NUM>. Each of the toner cartridges <NUM> is attachable to and detachable from the image forming apparatus <NUM> through the attachment unit, such as an attachment guide (not illustrated) and a positioning member (not illustrated), provided in the image forming apparatus <NUM>. The process cartridges <NUM> and the toner cartridges <NUM> will be described in detail below.

First to fourth toner conveyance devices <NUM> are arranged below the toner cartridges <NUM> so as to correspond to the respective toner cartridges <NUM>. The toner conveyance devices <NUM> upwardly convey the toner received from the respective toner cartridges <NUM>, and supply the toner to the respective developing units <NUM>.

An intermediate transfer unit <NUM> serving as an intermediate transfer member is provided above the process cartridges <NUM>. The intermediate transfer unit <NUM> is disposed substantially horizontally with primary transfer portions S1 located at the bottom side. An intermediate transfer belt <NUM> facing the photosensitive drums <NUM> is a rotatable endless belt, and is stretched on a plurality of stretching rollers.

On an inner surface of the intermediate transfer belt <NUM>, primary transfer rollers <NUM> serving as primary transfer members are disposed at positions at which primary transfer portions S1 are formed by the primary transfer rollers <NUM> and the respective photosensitive drums <NUM> via the intermediate transfer belt <NUM>. A secondary transfer roller <NUM> serving as a secondary transfer member, which is in contact with the intermediate transfer belt <NUM>, forms a secondary transfer portion S2 together with a counter roller via the intermediate transfer belt <NUM>. Further, an intermediate transfer belt cleaning unit <NUM> is disposed on a side opposite to the secondary transfer portion S2 in a lateral direction in <FIG> (direction in which secondary transfer portion S2 and intermediate transfer belt <NUM> are stretched).

A fixing unit <NUM> is disposed above the intermediate transfer unit <NUM>. The fixing unit <NUM> includes a heating unit <NUM> and a pressurizing roller <NUM> that comes into pressure contact with the heating unit <NUM>.

A discharge tray <NUM> is disposed on the top surface of the apparatus main body, and a waste toner recovery container <NUM> is disposed between the discharge tray <NUM> and the intermediate transfer unit <NUM>. A sheet feeding tray <NUM> for containing a recording medium <NUM> is disposed at a lowermost part of the apparatus main body.

Next, image forming operation by the image forming apparatus <NUM> will be described with reference to <FIG>, <FIG>.

In the image formation, each of the photosensitive drums <NUM> is rotationally driven in a direction of an arrow A in <FIG> at a predetermined speed. The intermediate transfer belt <NUM> is rotationally driven in a direction of an arrow B (forward direction to rotation of the photosensitive drums <NUM>).

First, surfaces of the photosensitive drums <NUM> are each uniformly charged by the respective charging rollers <NUM>. Next, the surfaces of the photosensitive drums <NUM> are scanned and exposed with a laser beam irradiated from the scanner unit <NUM>. Thus, an electrostatic latent image based on image information is formed on each of the photosensitive drums <NUM>.

The electrostatic latent image formed on each photosensitive drums <NUM> is developed as a toner image by the respective developing units <NUM>. At this time, the developing units <NUM> are each pressurized by respective developing pressurizing units (not illustrated) provided in the main body of the image forming apparatus <NUM>. Thereafter, the toner images formed on the photosensitive drums <NUM> are each primarily transferred to the intermediate transfer belt <NUM> by the respective primary transfer rollers <NUM>.

For example, in full-color image formation, the above-described processes are sequentially performed in the image forming units S1Y to S1K, which are the first to fourth primary transfer portions, and the toner image of the respective colors is sequentially superimposed on the intermediate transfer belt <NUM>.

By contrast, the recording medium <NUM> in the sheet feeding tray <NUM> is fed at a predetermined control timing, and is conveyed to the secondary transfer portion S2 in synchronization with a movement of the intermediate transfer belt <NUM>. The toner images of the four colors on the intermediate transfer belt <NUM> are collectively secondarily transferred to the recording medium <NUM> by the secondary transfer roller <NUM> that is in contact with the intermediate transfer belt <NUM> through the recording medium <NUM>.

Thereafter, the recording medium <NUM> on which the toner image has been transferred is conveyed to the fixing unit <NUM>. In the fixing unit <NUM>, the recording medium <NUM> is heated and pressurized. Thus, the toner image is fixed to the recording medium <NUM>. The recording medium <NUM> subjected to fixing is conveyed to the discharge tray <NUM>, and the image forming operation is completed.

Primary transfer residual toner (waste toner) remaining on the photosensitive drums <NUM> after the primary transfer process is removed by the cleaning blades <NUM>. Secondary transfer residual toner (waste toner) remaining on the intermediate transfer belt <NUM> after the secondary transfer process is removed by the intermediate transfer belt cleaning unit <NUM>.

The waste toner removed by the cleaning blades <NUM> and the intermediate transfer belt cleaning unit <NUM> is conveyed by the waste toner conveyance unit <NUM> provided in the apparatus main body, and is accumulated in the waste toner recovery container <NUM>. It should be noted that the image forming apparatus <NUM> can also form an image of a single color or multiple colors by using desired one or some (not all) of the image forming units.

Next, an entire configuration of one process cartridge <NUM> to be attached to the image forming apparatus <NUM> according to the present embodiment will be described with reference to <FIG>.

<FIG> is a conceptual perspective view of a non-drive side of one process cartridge (as viewed from above) according to the embodiment of the present invention. <FIG> is a conceptual perspective view illustrating a drive side of the process cartridge (as viewed from above) according to the embodiment of the present invention. <FIG> is a conceptual perspective view illustrating the drive side of the process cartridge (as viewed from above) according to the embodiment of the present invention, before coupling by a coupling portion.

More specifically, <FIG> is a perspective view of the process cartridge <NUM> as viewed from a front side (upstream side in process cartridge attachment direction). <FIG> is a perspective view of the process cartridge <NUM> as viewed from a back side (downstream side in process cartridge attachment direction).

The process cartridge <NUM> includes the cleaning unit <NUM> and the developing unit <NUM>. The cleaning unit <NUM> includes a cleaning frame member <NUM> that supports various members inside the cleaning unit <NUM>.

The cleaning unit <NUM> internally includes a waste toner conveyance screw <NUM> that extends in a direction parallel to a rotation axis direction of the photosensitive drum <NUM>, in addition to the photosensitive drum <NUM>, the charging roller <NUM>, and the cleaning blade <NUM>.

In the cleaning frame member <NUM>, cleaning bearings <NUM> that rotatably support the photosensitive drum <NUM> and include a cleaning gear train transmitting a driving force from the photosensitive drum <NUM> to the waste toner conveyance screw <NUM> are each disposed at respective longitudinal ends of the cleaning unit <NUM>.

The charging roller <NUM> provided in the cleaning unit <NUM> is urged toward the photosensitive drum <NUM> in the direction of an arrow C by a charging roller pressurizing spring (not illustrated). The charging roller <NUM> is provided to follow the photosensitive drum <NUM>. When the photosensitive drum <NUM> is rotationally driven in the direction of the arrow A in the image formation, the charging roller <NUM> is rotated in the direction of an arrow D (forward direction to rotation of photosensitive drum <NUM>).

The cleaning blade <NUM> provided in the cleaning unit <NUM> includes an elastic member 10a and a supporting member 10b. The elastic member 10a removes the transfer residual toner (waste toner) remaining on the surface of the photosensitive drum <NUM> after the primary transfer. The supporting member 10b supports the elastic member 10a.

The waste toner removed from the surface of the photosensitive drum <NUM> by the cleaning blade <NUM> is contained in a waste toner containing chamber <NUM> that is formed by the cleaning blade <NUM> and the cleaning frame member <NUM>. The waste toner contained in the waste toner containing chamber <NUM> is conveyed toward the back side of the image forming apparatus <NUM> (to downstream side in attachment and detachment direction of process cartridge <NUM>) by the waste toner conveyance screw <NUM> installed in the waste toner containing chamber <NUM>. The conveyed waste toner is discharged from a waste toner discharge portion <NUM>, and is passed to the waste toner conveyance unit <NUM> of the image forming apparatus <NUM>.

The developing unit <NUM> includes a development frame member <NUM> that supports various members inside the developing unit <NUM>. The development frame member <NUM> includes a developing chamber 16a and a toner containing chamber 16b (developing agent containing chamber). The developing chamber 16a is provided therein with the developing roller <NUM> and the supply roller <NUM>. The toner containing chamber 16b contains the toner and is provided therein with a stirring member <NUM>.

The developing chamber 16a is provided with the developing roller <NUM>, the supply roller <NUM>, and a developing blade <NUM>. The developing roller <NUM> bears the toner. In the image formation, the developing roller <NUM> is rotated in a direction of an arrow E, and comes into contact with the photosensitive drum <NUM> to convey the toner to the photosensitive drum <NUM>.

The developing roller <NUM> is rotatably supported to the development frame member <NUM> by a development bearing unit <NUM> at both ends of the developing roller <NUM> in the longitudinal direction (rotation axis direction). The supply roller <NUM> is rotatably supported to the development frame member <NUM> by the development bearing unit <NUM> while being in contact with the developing roller <NUM>. In the image formation, the supply roller <NUM> is rotated in the direction of an arrow F. Further, the developing blade <NUM> serving as a layer regulation member that regulates the thickness of a toner layer formed on the developing roller <NUM> is disposed so as to come into contact with the surface of the developing roller <NUM>.

In the toner containing chamber 16b, the stirring member <NUM> for stirring the contained toner T and conveying the toner to the supply roller <NUM> via a developing chamber communication opening 16c is provided. The stirring member <NUM> includes a rotary shaft 29a and a stirring sheet 29b. The rotary shaft 29a is parallel to the rotation axis direction of the developing roller <NUM>. The stirring sheet 29b serves as a conveyance member that is a flexible sheet. One end of the stirring sheet 29b is attached to the rotary shaft 29a, and the other end of the stirring sheet 29b is a free end. The rotation of the rotary shaft 29a rotates the stirring sheet 29b in the direction of an arrow G, and thus, the toner is stirred by the stirring sheet 29b.

The developing unit <NUM> includes the developing chamber communication opening 16c that makes the developing chamber 16a and the toner containing chamber 16b communicate with each other. In the present embodiment, in an attitude (attitude in use) at which the developing unit <NUM> is normally used, the developing chamber 16a is positioned above the toner containing chamber 16b. The toner drawn up by the stirring member <NUM> inside the toner containing chamber 16b is supplied to the developing chamber 16a through the developing chamber communication opening 16c.

The developing unit <NUM> is further provided with a toner receiving opening <NUM> (replenishing opening) at an end <NUM> on one end side in the attachment and detachment direction (i.e., longitudinal direction A1) (<FIG>). The toner receiving opening <NUM> is provided to open upward in a vertical direction A2.

A receiving opening sealing member <NUM> (sealing member) and a toner receiving opening shutter <NUM> that is movable in the attachment and detachment direction of the process cartridge <NUM> are provided on the toner receiving opening <NUM>. The receiving opening sealing member <NUM> includes a fiber member 45a made of polyester or the like, and an elastic member 45b made of sponge or the like. The receiving opening sealing member <NUM> is fixed to the toner receiving opening <NUM> by a fixing means, such as a double-sided tape.

In a case where the process cartridge <NUM> is not attached to the image forming apparatus <NUM>, the toner receiving opening <NUM> is closed by the receiving opening shutter <NUM>. The receiving opening shutter <NUM> is urged by the image forming apparatus <NUM> and is opened in conjunction with operation for attaching the process cartridge <NUM>.

Upon attachment of the process cartridge <NUM> to the image forming apparatus <NUM>, the receiving opening sealing member <NUM> comes into contact with a toner supply opening <NUM> of the apparatus main body, and is compressed in the direction W (compression direction) in <FIG>. In other words, the elastic force that is generated by the receiving opening sealing member <NUM> being compressed with a pressing force F1 from the toner supply opening <NUM> seals the receiving opening sealing member <NUM> and the toner supply opening <NUM>, thus preventing the toner from being scattered around the toner receiving opening <NUM>.

The toner discharged from the toner cartridge <NUM> described below is conveyed inside a toner conveyance path (not illustrated) provided inside the image forming apparatus <NUM>, and is supplied to the process cartridge <NUM> through the toner receiving opening <NUM>.

As illustrated in <FIG>, the developing unit <NUM> is provided with a reception conveyance path <NUM> that communicates with the toner receiving opening <NUM>, and a reception conveyance screw <NUM> is disposed inside the reception conveyance path <NUM>. Further, a containing chamber communication opening <NUM> that supplies the toner to the toner containing chamber 16b is provided near the longitudinal center of the developing unit <NUM>, and makes the reception conveyance path <NUM> and the toner containing chamber 16b communicate with each other. The reception conveyance screw <NUM> extends in parallel with the rotation axis direction of the developing roller <NUM> and the supply roller <NUM>, and conveys the toner received from the toner receiving opening <NUM> to the toner containing chamber 16b through the containing chamber communication opening <NUM>.

As described above, the developing unit <NUM> and the cleaning unit <NUM> are swingably coupled with each other. More specifically, as illustrated in <FIG>, holes 34a and 5a are respectively provided at both longitudinal ends of the development bearing unit <NUM> and the cleaning frame member <NUM>, and the developing unit <NUM> and the cleaning unit <NUM> are coupled by a rotation supporting pin <NUM> (coupling portion) (only one side in longitudinal direction is illustrated).

Accordingly, the development bearing unit <NUM> is swingably supported to the cleaning unit <NUM> with a center axis 30c (hereinafter, referred to as first rotation axis) of the rotation supporting pin <NUM> as an axis (rotation center 30c1).

In other words, in the process cartridge <NUM> according to the present embodiment, the developing roller <NUM> is movable to a position (P1) at which the developing roller <NUM> is in contact with the photosensitive drum <NUM>, and to a position (P2) at which the developing roller <NUM> is separated from the photosensitive drum <NUM> as illustrated in <FIG>. That is to say, when moving from the contact position P1 (contact state) to the separated position P2 (separated state), the developing roller <NUM> is moved in a direction in which a center C2 of the developing roller <NUM> is separated from a center C1 of the photosensitive drum <NUM>.

Next, one toner cartridge <NUM> according to the present embodiment will be described with reference to <FIG> is a conceptual sectional view of the toner cartridge used in the image forming apparatus according to the embodiment of the present invention.

The toner cartridge <NUM> includes a replenishment frame member <NUM> and a replenishment toner containing chamber <NUM>. The replenishment frame member <NUM> supports various members inside the toner cartridge <NUM>. The replenishment toner containing chamber <NUM> contains the toner therein. The replenishment toner containing chamber <NUM> is provided therein with a replenishment toner stirring member <NUM> and a replenishment toner conveyance screw <NUM>.

The replenishment toner stirring member <NUM> is disposed in parallel to the longitudinal direction of the toner cartridge <NUM>, and is rotatably supported to the replenishment frame member <NUM>. The replenishment toner stirring member <NUM> includes a rotary shaft portion 53a and a replenishment stirring conveyance sheet 53b including a flexible sheet. The rotation of the rotary shaft portion 53a rotates the replenishment stirring conveyance sheet 53b, and thus, the toner is conveyed to the replenishment toner conveyance screw <NUM>.

The replenishment toner conveyance screw <NUM> is disposed in parallel to the rotation axis of the replenishment toner stirring member <NUM>, and is rotatably supported to the replenishment frame member <NUM>. The replenishment toner conveyance screw <NUM> is rotated to convey the toner inside the replenishment toner containing chamber <NUM> from the front side to the back side (upstream side to downstream side in the toner cartridge attachment and detachment direction). The conveyed toner is discharged from the toner discharge opening provided on the downstream side of the replenishment toner conveyance screw <NUM>, into the toner conveyance path inside the image forming apparatus <NUM>. As described above, the toner discharged into the toner conveyance path inside the image forming apparatus <NUM> is replenished into the developing unit <NUM> through the toner receiving opening <NUM> illustrated in <FIG>.

Next, positional relationship between the receiving opening sealing member <NUM> and the first rotation axis 30c will be described with reference to <FIG>.

<FIG> is a conceptual side view of a process cartridge included in the image forming apparatus according to the embodiment of the present invention. <FIG> is an enlarged conceptual diagram of a main part near the replenishing opening. <FIG> is a conceptual diagram illustrating positional relationship between the sealing member and the coupling portion as viewed along a direction M illustrated in <FIG>.

As described above, the process cartridge <NUM> according to the present embodiment includes the cleaning unit <NUM> including the photosensitive drum <NUM>, and the developing unit <NUM> including the development frame member <NUM> in which the developing roller <NUM> is supported.

The cleaning unit <NUM> and the developing unit <NUM> are swingably coupled by the rotation supporting pin <NUM>, and the developing unit <NUM> is configured to be swingable with respect to the cleaning unit <NUM> with the rotation supporting pin <NUM> as the rotation center 30c1.

Further, the development frame member <NUM> includes the toner receiving opening <NUM> that is connectable to the supply portion <NUM> (see <FIG>) of the image forming apparatus <NUM>. The toner receiving opening <NUM> is provided with the elastically-deformable receiving opening sealing member <NUM> that seals the supply portion <NUM> and the toner receiving opening <NUM> to prevent leakage of the toner.

When the supply portion <NUM> and the toner receiving opening <NUM> are connected to each other, the pressing force F1 (see <FIG>) is generated in the section (see <FIG>) orthogonal to the longitudinal direction A1. As viewed along the compression direction W of the receiving opening sealing member <NUM> that is compressed with the pressing force F1 between the supply portion <NUM> and the toner receiving opening <NUM>, the rotation center 30c1 is disposed at a position <NUM> overlapping with the receiving opening sealing member <NUM>.

In the present embodiment, in a state where the process cartridge <NUM> is attached to the apparatus main body of the image forming apparatus <NUM>, the receiving opening <NUM> receives the downward pressing force F1 in the vertical direction (direction W), from the supply portion <NUM>.

More specifically, the developing unit <NUM> is supported so as to be swingable with respect to the cleaning unit <NUM> around the rotation supporting pin <NUM>. The development bearing unit <NUM> is provided with a pressed portion 34b. In the image formation, the pressed portion 34b is pressed in the direction H in <FIG> by a pressing unit <NUM> provided in the image forming apparatus <NUM>. In <FIG>, although only one side of the process cartridge in the longitudinal direction is illustrated, the other side of the process cartridge is similarly configured. Thus, a moment in the direction of an arrow K around the first rotation axis 30c acts on the developing unit <NUM>, and the developing roller <NUM> can come into contact with the photosensitive drum <NUM> with a certain intrusion amount.

In the present embodiment, as viewed from the longitudinal direction A1 in the attitude in use, the pressed portion 34b is positioned on one side (C5), and the photosensitive drum <NUM> is positioned on the other side (C6) with respect to a perpendicular (C4) passing through the rotation center (30c1).

As described above, when the process cartridge <NUM> is attached to the image forming apparatus <NUM>, the receiving opening sealing member <NUM> provided at the toner receiving opening <NUM> comes into contact with the toner supply opening <NUM> provided inside the image forming apparatus <NUM> and is pressed in the direction M illustrated in <FIG>.

In the present embodiment, as illustrated in <FIG>, the receiving opening sealing member <NUM> and the rotation supporting pin <NUM> have such a positional relationship that the first rotation axis 30c passes through the area of the receiving opening sealing member <NUM> as viewed along the compression direction W of the receiving opening sealing member <NUM>. In other words, as viewed along the compression direction W, the sealing member <NUM> and the rotation center 30c1 are disposed at the position <NUM> at which the sealing member <NUM> and the rotation center 30c1 overlap.

Thus, the moment around the first rotation axis 30c produced by the pressing force F1, received by the receiving opening sealing member <NUM> from the toner supplying opening <NUM> (supply portion) of the image forming apparatus <NUM>, turns in the opposite direction with the first rotation axis 30c in <FIG> as a boundary. In other words, in <FIG>, the moment in the direction K illustrated in <FIG> occurs in an area S1 which is an area on the left side of the first rotation axis 30c, and the moment in the direction N illustrated in <FIG> occurs in an area S2 which is an area on the right side of the first rotation axis 30c. Thus, the moments occurred in the areas S1 and S2 are canceled by each other, which makes it possible to weaken the generated moments around the first rotation axis 30c.

In other words, the disposition of the receiving opening sealing member <NUM> immediately above the first rotation axis 30c reduces influence on the pressing force F2 of the developing roller <NUM> against the photosensitive drum <NUM>, caused by the pressing force F1 received by the receiving opening sealing member <NUM>.

This also applies to a case where the elastic force or the position of the receiving opening sealing member <NUM> is changed due to a variation of components. The pressing unit <NUM> of the main body of the image forming apparatus <NUM> can stably press the developing roller <NUM> against the photosensitive drum <NUM>.

Even in a case where the toner intervenes the receiving opening sealing member <NUM> and the elastic force of the receiving opening sealing member <NUM> changes while the process cartridge <NUM> is used, it is possible to stably press the developing roller <NUM> against the photosensitive drum <NUM>.

In the present embodiment, the toner receiving opening <NUM> and the receiving opening sealing member <NUM> are provided in a circular area (C3) that has a radius L1 (rotation radius) about the first rotation axis 30c (<FIG>). As illustrated in <FIG>, the radius L1 is a distance between the first rotation axis 30c and the pressed portion 34b projected on a plane orthogonal to the first rotation axis 30c.

In the present embodiment, the receiving opening sealing member <NUM> is disposed at a position close to the first rotation axis 30c as compared with the pressed portion 34b that receives the pressing force from the main body of the image forming apparatus <NUM>. This makes it possible to reduce the influence on the pressing force of the developing roller <NUM> against the photosensitive drum <NUM>, caused by the pressing force that the receiving opening sealing member <NUM> receives.

As described above, even in the case where the elastic force, the attachment position, etc. of the receiving opening sealing member vary, the process cartridge according to the present embodiment can stably press the developing roller <NUM> against the photosensitive drum <NUM>, which results in an excellent image.

This enables replenishment of the developing agent and can improve stability of the contact state between the image bearing member and the developing agent bearing member.

According to embodiments of the present invention, it is possible to replenish the developing agent, and to improve stability of the contact state between the image bearing member and the developing agent bearing member.

Claim 1:
A process cartridge (<NUM>), comprising:
a first unit (<NUM>) including an image bearing member (<NUM>) configured to bear a developing agent image;
a second unit (<NUM>) including a development frame member (<NUM>) in which a developing agent bearing member (<NUM>) is supported, the developing agent bearing member being configured to bear a developing agent to be supplied to the image bearing member (<NUM>); and
a coupling portion (<NUM>) configured to couple the first unit (<NUM>) and the second unit (<NUM>) such that the second unit (<NUM>) is swingable with respect to the first unit (<NUM>) around a center axis (30c) of the coupling portion, between a contact position (P1) in which the developing agent bearing member (<NUM>) is in contact with the image bearing member (<NUM>) and a separated position (P2) in which the developing agent bearing member (<NUM>) is separated from the image bearing member (<NUM>),
wherein the development frame member (<NUM>) includes a replenishing opening (<NUM>) through which the developing agent is replenished from a supply portion (<NUM>) of an image forming apparatus (<NUM>) in a state where the replenishing opening communicates with the supply portion (<NUM>), and an elastically-deformable sealing member (<NUM>) that contacts the replenishing opening (<NUM>) and the supply portion (<NUM>), and seals a gap between the supply portion (<NUM>) and the replenishing opening to prevent leakage of the developing agent therebetween, and
wherein, as viewed in a compression direction (W) in which the sealing member (<NUM>) is compressed between the supply portion and the replenishing opening with a pressing force (F1), the coupling portion is overlapped with the sealing member.