Developer accommodating container, process cartridge and electrophotographic image forming apparatus

A developer accommodating unit includes: a flexible container, provided with an opening for permitting discharge of a developer, for accommodating the developer; a frame for accommodating the flexible container and for accommodating the developer discharged from the flexible container; and an urging member, provided inside the frame, for urging the flexible container to deform the flexible container. The flexible container has a plurality of sides, where the developer accommodated inside the flexible container receives gravitation, defined by a bent portion. The sides are capable of receiving an urging force of the urging member.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a developer accommodating unit for use with an image forming apparatus, a process cartridge including the developer accommodating unit, and an electrophotographic image forming apparatus in which these members are incorporated.

The image forming apparatus forms an image on a recording material (medium) by using, e.g., an electrophotographic image forming process and may include, e.g., an electrophotographic copying machine, an electrophotographic printer (such as an LED printer or a laser beam printer), an electrophotographic facsimile machine, and the like.

Further, the process cartridge refers to a cartridge, prepared by integrally assembling at least a developing means and a developing device, detachably mountable to a main assembly of the image forming apparatus and refers to a cartridge, prepared by integrally assembling the developing device and a photosensitive member unit including at least a photosensitive member, detachably mountable to the main assembly of the image forming apparatus.

Further, a developer accommodating container and the developer accommodating unit are accommodated in the image forming apparatus or the process cartridge. The developer accommodating unit container and the developer accommodating unit at least include a flexible container for accommodating the developer.

In a conventional electrophotographic image forming apparatus using the electrophotographic image forming process, a process cartridge type in which an electrophotographic photosensitive member and process means acting on the photosensitive member are integrally assembled into a cartridge and this cartridge is detachably mountable to a main assembly of the electrophotographic image forming apparatus is employed.

In such a process cartridge, as shown inFIG. 20, an opening provided to a developer accommodating frame34for accommodating a developer (toner, carrier, etc.) is sealed with a sealing member. Further, a type in which a bonding portion33of a toner seal32as a sealing member is peeled off at the time of use to unseal the opening, thus enabling feeding (supply) of the developer has been widely employed (Japanese Laid-Open Patent Application (JP-A) Hei 04-66980, FIG. 13).

Further, in order to solve a problem such that the developer is scattered in the process cartridge in a developer filling step during manufacturing of the process cartridge, a constitution in which a deformable inside container is used has been devised (JP-A Hei 04-66980).

In the conventional technique, for the purpose of improving operativity of the developer feeding and of reducing a cost of a developer feeding device by preventing the scattering of the developer in the process cartridge, a method of accommodating the developer in the deformable inside container (flexible container) is described. However, in this method, operation and mechanism relating to discharge of the developer after the unsealing are not described.

Further, in the case where the deformable inside container was used inside the cartridge, the following deformation was generated in a bottom side, with respect to a vertical direction, where powder pressure of a filled developer is applied. For example, in a constitution in which the deformable inside container is hung, by self-weight of the filled developer, the inside container is flexed in the (downward) vertical direction. In this case, when a rotatable member such as a feeding member for feeding the developer is provided in the neighborhood of the bottom of the inside container, a position relationship between the rotatable member and the inside container is, even when it is a non-contact state at an initial stage, a contact state when a degree of flexure is increased. For that reason, there was a possibility that an excessive torque was generated in the rotatable member and thus a stopping motor of the image forming apparatus caused loss of synchronism. In order to avoid the contact between the rotatable member and the inside container, there is a need to design, in consideration of an estimated maximum flexure amount, the positional relationship so as to space the rotatable member and the inside container. For this reason, there was a possibility that the process cartridge was increased in size.

SUMMARY OF THE INVENTION

A principal object of the present invention is to provide a developer accommodating unit capable of increasing strength of a flexible container at a portion, where powder pressure of a developer is applied, to reduce a degree of flexure of the flexible container and thus capable of compatibly realizing downsizing of a developing device and improvement in efficiency of discharge of the developer from the flexible container.

According to an aspect of the present invention, there is provided a developer accommodating unit comprising: a flexible container, provided with an opening for permitting discharge of a developer, for accommodating the developer; a frame for accommodating the flexible container and for accommodating the developer discharged from the flexible container; and an urging member, provided inside the frame, for urging the flexible container to deform the flexible container, wherein the flexible container has a plurality of sides, where the developer accommodated inside the flexible container receives gravitation, defined by a bent portion, and wherein the sides are capable of receiving an urging force of the urging member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2is a sectional view showing a structure of an image forming apparatus100. As shown inFIG. 2, the image forming apparatus100as an electrophotographic image forming apparatus includes an apparatus main assembly B as an image forming apparatus main assembly and is constituted so that a cartridge A as a process cartridge is detachably mountable to the apparatus main assembly B. The cartridge A is prepared by integrally assembling a photosensitive drum1and a developer accommodating unit25. In a sheet cassette6mounted to a lower portion of the apparatus main assembly B, sheets S are accommodated. During image formation, the sheet S is fed toward the photosensitive drum11, as an electrophotographic photosensitive drum which is an image bearing member, by a feeding roller7.

In synchronism with this operation, the surface of the photosensitive drum11is electrically charged uniformly by a charging roller12and exposed to light by an exposure device8, so that an electrostatic latent image is formed on the surface of the photosensitive drum11. In the cartridge A, a developer is accommodated and a developing roller13as a developer carrying member is provided. The developer is fed to the developing roller13by a supplying roller23to be carried in a thin layer on the surface of the developing roller13by a developing blade15. Then, a developing bias is applied to the developing roller13, so that the above-described electrostatic latent image is developed with the developer and thus a developer image is formed on the surface of the photosensitive drum11.

The developer image is transferred onto the conveyed sheet S by a transfer roller9supplied with a bias voltage. Then, the sheet S is conveyed to a fixing device10to fix the developer image thereon, and then is discharged onto a discharge portion3by a discharging roller pair1. Incidentally, the apparatus main assembly B includes a controller50, and the controller50controls drive of inside devices of the apparatus main assembly B. Further, although described later, the controller50controls drive of an urging sheet21(FIG. 1) so that the urging sheet21can repetitively urge a developer accommodating member16(FIG. 1) which is a flexible container by rotating the urging sheet21.

<Summary of Structure of Process Cartridge>

FIG. 1is a sectional view showing a structure of the cartridge A. As shown inFIG. 1, the cartridge A includes a cleaner unit24and the developer accommodating unit25. The cleaner unit24includes the photosensitive drum11, a cleaning blade14for cleaning the surface of the photosensitive drum11, and the charging roller12for electrically charging the surface of the photosensitive drum11. The developer accommodating unit25includes the developing roller13, the supplying roller23for supplying the developer to the developing roller13, and the developer accommodating member16for accommodating the developer. The developer accommodating unit25will be described specifically below.

The developer accommodating unit25includes a frame17as a first frame and a frame18as a second frame. In an upper region of the frames17and18, the developer accommodating member16and an urging member500(urging body or urging means) are disposed. The urging member500includes, although described later, the urging sheet21, a sealing member19and a rotatable member20. The present invention is characterized by the developer accommodating member16which is the flexible container. The developer accommodating member16is provided with openings35afor permitting discharge of a developer G (G1), and is a container for accommodating the developer G (G1). In a lower region of the frames17and18, the developing roller13and the supplying roller23are disposed. By employing such a constitution, the developer accommodating unit25is configured to accommodate the developer accommodating member16containing the developer in the upper region of the frames17and18and to accommodate the developer G (G2) after being discharged from the developer accommodating member16in the lower region of the frames17and18.

The urging member500is disposed below, with respect to a vertical direction, an opening-containing side X of the developer accommodating member15. The urging member includes the rotatable member20, the sealing member19and the urging sheet21. Further, at a surface of the rotatable member20, the sealing member19and the urging sheet21are fixed. The sealing member19is a member for urging the developer accommodating member16after the sealing member19seals the openings35aand then unseals the openings35aby rotation of the rotatable member20. Further, the urging sheet21urges, during or after an operation in which the sealing member19unseals the openings35a, the opening-containing side X of the developer accommodating member16to deform the developer accommodating member16.

The developer accommodating member16includes the opening-containing side X. The opening-containing side X includes a first sides X1and a second side X2which are side where the developer G accommodated in the developer accommodating member16receives gravitation and which are a plurality of sides defined by a bent portion16rfor bending the sides, and the first side X1and the second side X2receive an urging force of the urging member500. The first side X1and the second side X2are partitioned by the bent portion16r, as a boundary, for bending the opening-containing side X, and the first side X1is disposed at an upper position than the second side X2with respect to the vertical direction. The opening-containing side X further includes a third side X3, and between the second side X2and the third side X2, the openings35aare formed. The second side X2is disposed at an upper position than the third side X2with respect to the vertical direction.

Thus, the opening-containing side X has the constitution including the bent portion16r, and therefore compared with a constitution in which the opening-containing side is formed as a flat side which does not include the bent portion16r, the opening-containing side X is strong against flexure (bending) and thus is increased in strength. Therefore, even when the rotatable member20is disposed at an opposing position to the second side X2, the strength of the opening-containing side X is increased, and therefore the opening-containing side X is prevented from being flexed (bent) by the weight of the developer filled (accommodated) inside the developer accommodating member16and thus all the loads are not exerted on the rotatable member20. As a result, the rotatable member20can be disposed at a position closer to the developer accommodating member16, and therefore the developer accommodating unit25can be lowered in height with respect to the vertical direction, thus leading to downsizing of the cartridge A. Incidentally, the reason why the opening-containing side X is strong against the flexure by including the bent portion16rwill be explained in (Structure of developer accommodating member16) described later.

<Summary of Structure of Developer Accommodating Unit>

Part (a) ofFIG. 3is a perspective view showing an inside mechanism of the frames17and18in cross section.FIG. 4is a sectional view showing a structure of the developer accommodating unit25and shows a state in which a sealing portion19aof the sealing member19closes (covers) the openings35a.FIG. 6is a sectional view showing a structure of the developer accommodating unit25and shows a state in which the sealing portion19aof the sealing member19opens (unseals) the openings35a.

As shown inFIG. 3, at an upper portion of the developer accommodating member16, fixing portions16efor fixing the developer accommodating member16to the frames17and18are formed, and at a lower portion of the developer accommodating member16, fixing portions16dfor fixing the developer accommodating member16to the frame17are formed. The fixing portions16eand16dare holes. At a part of the surface of the developer accommodating member16, a discharging portion35extending in a longitudinal direction of the flexible container16is formed. The discharging portion35includes the openings35afor permitting the discharge of the developer and connecting portions35bfor connecting (defining) the openings35a. Herein, a side including the discharging portion35is referred to as the opening-containing side X also from the viewpoint that the side contains the openings35a.

At an opposing position to the opening-containing side X of the developer accommodating member16, the rotatable member20is disposed. The rotatable member20is a member rotatable about its shaft (axis) as a rotation center. On the rotatable member20, a base end portion of the sealing member19is fixed. Specifically, as shown inFIG. 4, the sealing member19includes an engaging portion19b, a connecting portion19cand the sealing portion19a. The engaging portion19bis fixed on the rotatable member20, and the sealing portion19ais fixed on the discharging portion35. When the rotatable member20is rotated in an arrow C direction, the sealing portion19aopens the openings35a. The sealing member19is fixed on the rotatable member20at the engaging portion19bby a retaining member (FIG. 4) and is fixed on the discharging portion35so as to block the openings35aat the sealing portion19a.

As shown inFIG. 4, on the rotatable member20, the urging sheet21is fixed. When the rotatable member20is rotated, the urging sheet21urges and urge-releases the developer accommodating member16while being rotated. The urging sheet21is fixed on the rotatable member20at its base end portion by a retaining member. The fixing portions16eof the developer accommodating member16are fixed to fixing portions18bof the frame18. The fixing portions16dof the developer accommodating member16are fixed to fixing portions18cof the frame18. Thus, the developer accommodating member16is supported inside the frames17and18.

As shown inFIG. 6, when the rotatable member20is rotated, the sealing portion19aof the sealing member19is gradually separated (peeled) from the openings35a. At the same time, the urging sheet21approaches the developer accommodating member16in order to urge the developer accommodating member16.

(Developer Accommodating Member in which Developer is Accommodated)

Parts (a) to (c) ofFIG. 30are perspective views showing a structure of the developer accommodating member16. As shown in (a) ofFIG. 30, the developer accommodating member16is provided, at its one longitudinal end, with a filling opening39through which the developer is to be injected. Further, the developer accommodating member16is provided, at its side, with the plurality of openings35aarranged in a line in the longitudinal direction (although the openings35amay also be arranged in a plurality of lines). To the openings35aof the developer accommodating member16, the sealing member19is applied. Thus, an end portion of the sealing member19is applied onto the developer accommodating member16so as to seal the openings35a, and at a base end portion of the sealing member19, a hole as the engaging portion19bto be engaged with the retaining member of the rotatable member20is formed. Incidentally, the developer is powder. Further, in a state shown in (a) ofFIG. 30, the developer accommodating member16is not filled with the developer and the filling opening39for permitting the filling of the developer is open.

As shown in (b) ofFIG. 30, the developer is injected (charged) into the developer accommodating member16from the filling opening39in an arrow direction, so that the inside of the developer accommodating member16is filled with the developer. By flexibility of the developer accommodating member16, the filling opening39for permitting the filling of the developer is deformable correspondingly to a filling device and thus the filling of the developer is facilitated without causing scattering of the developer. For filling the developer, a known auger type filling device is used but another method (means) having a similar function may also be used.

As shown in (c) ofFIG. 30, when the developer accommodating member16is filled with the developer, the developer accommodating member16is bonded at a bonding portion39a. Thus, the respective openings35aand the filling opening39of the developer accommodating member16in which the developer is accommodated are sealed and therefore the accommodated developer does not leak out of the developer accommodating member16, so that the developer accommodating member16can be treated as a single unit. The bonding of the bonding portion39aof the filling opening39for permitting the filling of the developer is made by ultrasonic bonding in this embodiment but may also be made by other bonding methods using heat, a laser and the like. Incidentally, a position and a size of the filling opening39for permitting the filling of the developer may appropriately selected correspondingly to shapes and the like of the developer filling device and the (process) cartridge A.

(Effect of Incorporating Developer Accommodating Member in Frame)

By forming the developer accommodating member16, in which the developer is accommodated, in a bag shape, the developer can be treated as a unit. For that reason, a developer filling step can be separated from a main assembling step (manufacturing line) of the cartridge A. As a result, the developer is prevented from being scattered in the main assembling step (manufacturing line) of the cartridge A, so that maintenance such as cleaning of the manufacturing line can be reduced. By the prevention of the scattering of the developer during the assembling step, it is possible to omit a cleaning step of the cartridge A to be performed after the developer filling.

Also in the filling step of the developer in the developer accommodating member16, the developer accommodating member16has flexibility, and thus the filling opening39for permitting the developer filling is also soft and therefore can be easily sealed with less scattering of the developer.

Further, the developer accommodating member16in which the developer is accommodated has flexibility and therefore can be assembled while following a shape of the frame.

Further, in the filling step, the developer accommodating member16has flexibility and therefore deforms its cross section to increase its volume in which the developer can be filled, so that a filling amount can be increased during the filling.

Further, the flexible container37before the developer filling has flexibility and thus can be made small (thin), so that a storing space during storage before the filling can be decreased compared with the frame which is a resinous structure.

(Structure of Developer Accommodating Member16)

In this embodiment, as the flexible container, the developer accommodating member16is used. Here, referring again toFIG. 3, description will be made.

As shown inFIG. 3, the developer accommodating member16in this embodiment is constituted by a molded portion16awhich is a flexible container formed by the vacuum molding, the air-pressure molding and the press molding and constituted by a sheet-like air permeable portion16b. The molded portion16aand the air permeable portion16bare bonded by (heat) welding, laser welding, adhesive bonding, adhesive tape bonding or the like. The developer accommodating member16accommodated therein the developer and has a flexible shape, and is provided with the plurality of openings35a, for permitting discharge of the accommodated developer, at the discharging portion35. Further, the developer accommodating member16includes the fixing portions (portions-to-be-fixed)16dand16ewhich are fixed to the frames17and18.

The molded portion16ais formed in a shape close to a hat-like shape (trapezoidal configuration) and includes an upper bottom side16j, a perpendicular side16gand the opening-containing side X (tapered portion). From the perpendicular side16g, an outer peripheral side16c1is extended upward vertically, and from the opening-containing side X, an outer peripheral side16c2is extended downward vertically. The outer peripheral sides16c1and16c2are bonded to the air permeable portion16b. Further, at the outer peripheral side16c2, fixing portions16dto be fixed to the frame18are formed. The shape of the molded portion16afollows the inside shape of the frames17and18(FIG. 3).

On the developer accommodating member16, the sealing member19for closing and unsealing the openings34aof the discharging portion35is mounted. The sealing member19is mounted on one side of the rotatable member20.

Part (a) ofFIG. 18is a partly enlarged sectional view showing a structure of the developer accommodating unit25, and corresponds to a sectional view as seen from an arrow R2direction of (b) ofFIG. 18. Part (b) ofFIG. 18corresponds to a sectional view as seen from an arrow R2direction of (a) ofFIG. 18, and a broken line portion of (a) ofFIG. 18corresponds to a broken line portion of (b) ofFIG. 18. As shown in (b) ofFIG. 18, the opening-containing side X on which the self-weight of the developer filled in the developer accommodating member16is exerted is formed in a projection shape projected upward with respect to the vertical direction. This projection shape is formed in a shape and that the opening-containing side X is recessed from a phantom plane connecting supporting points16pand16q. Further, the opening-containing side X is, as shown in (a) ofFIG. 18, formed so that the bent portion16rextends in a single rectilinear line shape parallel to a shaft of the rotatable member20as seen from a side surface. The first side X1is formed in a flat plane parallel to the shaft of the rotatable member20as seen from the side surface. The second side X2is formed in a flat plane parallel to the shaft of the rotatable member20as seen from the side surface.

Part (c) ofFIG. 18is a partly enlarged sectional view showing a structure of a developer accommodating unit according to Comparison example, and corresponds to a sectional view as seen from an arrow R2direction of (d) ofFIG. 18. Part (d) ofFIG. 18corresponds to a sectional view as seen from an arrow R2direction of (c) ofFIG. 18, and a broken line portion of (c) ofFIG. 18corresponds to a solid line portion connecting the supporting points16pand16qin (d) ofFIG. 18. As shown in (c) and (d) ofFIG. 18, in the developer accommodating member in Comparison example, the opening-containing side X is not provided with the bent portion16r, and is formed in a rectilinear line shape from the supporting point16pto the supporting point16qas seen from a sectional surface.

The reason why the opening-containing side X is strong against the flexure by providing the bent portion16rto the opening-containing side X as in this embodiment will be described below. As shown in (d) ofFIG. 18, in the case where the opening-containing side X does not include the bent portion16r, it would be considered that the opening-containing side X is a both end support beam supported at the supporting point16pfixed to the air permeable portion16band the supporting point16qfixed to the upper bottom portion16j. As shown in (b) ofFIG. 18, in the case where the opening-containing side X includes the bent portion16r, in the opening-containing side X, the bent portion16rconstitutes a supporting point fixed to sides16hand16i, so that when such a bent portion16ris provided, the supporting points are three in total and thus the strength (stiffness) of the beam is increased.

Here, in this embodiment, the case where the developer inside the developer accommodating member16is discharged and thus the developer remaining in the developer accommodating member16becomes small in amount will be described. Most of the developer remaining in the developer accommodating member16is present on the opening-containing side X. The developer remaining on the opening-containing side X is moved toward the openings35aalong the surface of the opening-containing side X, and is discharged while being moved toward the neighborhood of the openings35aby vibration generated when the urging member500contacts the developer accommodating member16. Further, when the amount of the developer remaining in the developer accommodating member16becomes small, the developer is gradually placed in a state in which the developer remains on the opening-containing side X at a position closer to the openings35a.

In order to create such a state, as shown in (b) ofFIG. 18, with the position closer to the openings35a, a degree of inclination of the first and second sides X1and X2with respect to the direction of gravitation is increased. Specifically, shapes of the first and second sides X1and X2are set so that the downward inclination with respect to the vertical direction is more abrupt in the second side X2passing through the supporting points16rand16qthan in the first side X1passing through the supporting points16rand16q, so that a two-stage inclination constitution is employed. Further, a constitution in which even when the amount of the developer remaining inside the developer accommodating member16becomes small, the developer is easily discharged is employed. Incidentally, the openings35aare disposed below the bent portion16rwith respect to the vertical direction.

Part (e) ofFIG. 18is a partly enlarged sectional view showing a structure of a developer accommodating unit according to a modified embodiment, and corresponds to a sectional view as seen from an arrow R2direction of (f) ofFIG. 18. Part (f) ofFIG. 18corresponds to a sectional view as seen from an arrow R2direction of (e) ofFIG. 18, and a broken line portion of (e) ofFIG. 18corresponds to a solid line portion connecting the supporting points16pand16qin (f) ofFIG. 18. This modified embodiment is characterized in that a groove16tvertically recessed upward from the opening-containing side X is formed. This groove16tis, in (f) ofFIG. 18, as indicated by a broken line, formed in an upward projection shape with respect to the vertical direction (see also (g) ofFIG. 18). Also by such a groove16t, the stiffness of the opening-containing side X is increased.

Part (g) ofFIG. 18is a sectional view showing a structure of an opening-containing side X according to the modified embodiment, and corresponds to a sectional view as seen from an arrow R3direction of (e) ofFIG. 18. In the case where such a single groove16tas described above is provided to the opening-containing side X, in addition to an intersection between the side16hand the groove16tand an intersection between the opening-containing side X and the groove16t, a portion functioning as the beam is newly increased. For that reason, the stiffness of the opening-containing side X is increased.

Parts (h), (i) and (j) ofFIG. 18are sectional views each showing a structure of an opening-containing side X according to a further modified embodiment. In (h) ofFIG. 18, an X-shaped groove16tis formed in the opening-containing side X.

In (i) ofFIG. 18, a plurality of grooves16textending in an axial direction of the rotatable member20is formed in the opening-containing side X. In (j) ofFIG. 18, square grooves16tare formed in the opening-containing side X so that two square grooves16tarranged in the axial direction of the rotatable member20with a predetermined interval with respect to a direction perpendicular to the axial direction and so that three square grooves16tare arranged in the direction perpendicular to the axial direction with a predetermined interval with respect to the axial direction. As a result, the six square grooves16tare formed in total. These grooves are not necessarily formed with the predetermined intervals and in a limited number, but it would be considered that the same effect can be obtained by forming the plurality of grooves in such a manner. In the case where the various uneven shapes as described above are provided, the same effect can be obtained.

When the recessed portion as seen from the inside of the developer accommodating member16is provided in the opening-containing side X, the developer is liable to remain, and therefore it is desirable that such a recessed portion is not provided. However, even when the recessed portion with respect to the vertical direction is provided, if the recessed portion has a groove shape descending toward the openings35a, the developer can be moved and therefore there is no problem.

By forming the molded portion16athrough the vacuum molding, the following effects are obtained.

As a first effect, the developer accommodating member34can be shaped so as to follow the inside shape of the frame. For that reason, it is possible to dispose the bag until corner portions of the frame, so that a space (spacing) is prevented from being formed between the developer accommodating member16and the frame17and thus the space does not constitute a dead space.

As a second effect, the developer accommodating member16can be shaped so as to follow the shape of the frame and therefore can be easily assembled with the frame. This is because there is no need to push the developer accommodating member into the frame during the assembling so that its shape follows the shape of the frame.

As a third effect, control of the thickness and shape of each of the molded sides depending on molding shape and condition becomes easy. As a result, it becomes possible to control the stiffness of the side containing the openings35aby providing the uneven shape to the side containing the openings35aas in this embodiment.

(Positional Relationship Between Rotatable Member and Developer Accommodating Member)

Part (b) ofFIG. 3is a partial sectional view showing a structure of the developer accommodating unit25. As shown in (b) ofFIG. 3, in this embodiment, in order to downsize the developer accommodating unit25, a positional relationship between the rotatable member20and the developer accommodating member16is set. Specifically, a part of the rotatable member20is disposed at a position closer to the opening-containing side X than the phantom plane connecting the supporting points16pand16q. That is, the rotatable member20is disposed such that the part thereof enters the recessed portion formed by the opening-containing side X.

This is a result that the constitution in which the opening-containing side X is provided with the bent portion16rand thus is stronger against the flexure than the case where the opening-containing side X is not provided with the bent portion16r. That is, even when the rotatable member20is disposed in the neighborhood of the opening-containing side X, the stiffness of the opening-containing side X is increased and therefore a phenomenon that the opening-containing side X is flexed by the weight of the developer filled inside the developer accommodating member16is suppressed. Accordingly, there is no need to take into consideration a risk such that all the loads of the developer are exerted on the rotatable member20.

If the above positional relationship is se based on the premise that the risk occurs, in order not to cause loss of synchronism of the stepping motor of the image forming apparatus due to generation of an excessive torque in the rotatable member20, there is a need to dispose the developer accommodating member16and the rotatable member20with a large spacing. For that reason, the developer accommodating unit is increased in size.

Part (c) ofFIG. 3is a partial sectional view showing a structure of the developer accommodating unit25. As shown in (c) ofFIG. 3, the case where the width of the developer accommodating member16is larger than the width of the developer accommodating unit25(i.e., the spacing between the frames17and18) with respect to the horizontal direction is assumed. In this case, the developer accommodating member16has the flexibility and therefore the developer accommodating member16is fixed inside the developer accommodating unit25in a state in which the upper bottom portion16jis deformed by the frame17. In this case, the supporting points16pand16sfunctions as a supporting point of the developer accommodating member16, and by providing an uneven shape to a phantom plane connecting the supporting points16pand16s, an effect of being strong against the flexure is similarly obtained.

(Material and Air Permeability of Developer Accommodating Member)

Part (a) ofFIG. 29is a sectional view for illustrating the structure of the developer accommodating member16and the sealing member19. The developer accommodating member16is constituted by bonding the molded portion16awhich includes the openings35aand which does not have air permeability, and the sheet-like air permeable portion16bwhich has the air permeability and which is an air permeable portion to each other.

Here, a degree of the air permeability of the sheet-like air permeable portion16bwhich is the air permeable portion may appropriately be selected so that the developer is prevented from leaking out of the developer accommodating member16based on a balance with a size of the developer (particle size of powder) to be accommodated.

As the material for the molded portion16a, materials such as ABS, PMMA, PC, PP, PE, HIPS, PET, PVC and composite multi-layer materials of these materials may preferably be used. The thickness of the molded portion16ain the sheet shape before the molding may preferably be about 0.1-1 mm. The material and thickness of the molded portion16amay appropriately be selected depending on cost, product specification, manufacturing condition, and the like.

As a material for the sheet-like air permeable portion16b, a nonwoven fabric or the like formed of polyethylene telephthalate (PET), polyethylene (PE), polypropylene (PP) or the like in a thickness of 0.03-0.15 mm may preferably be used. Further, even when the material for the sheet-like air permeable portion16bis not the nonwoven fabric, a material having minute holes which is smaller in diameter than the powder such as the developer accommodated in the developer accommodating member16may also be used.

Further, in this embodiment, as shown inFIGS. 3 and 29, the sheet-like air permeable portion16bis disposed over the entire region of the developer accommodating member16with respect to a longitudinal direction in the frame18side. As shown in (b) ofFIG. 29, the sheet-like air permeable portion16bmay also constitute the entire developer accommodating member16.

As a material for the developer accommodating member16other than the sheet-like air permeable portion16b, a material having flexibility so as to improve an efficiency during the discharge of the developer described later may preferably be used. Further, the material for the air sheet-like air permeable portion16bmay also have flexibility.

(Effect of Developer Accommodating Member Having Air Permeability)

The reason why the air permeability is imparted to the developer accommodating member16as described above is that the developer accommodating member16can meet states during manufacturing, during transportation until a user uses the cartridge A, and during storage. First, the reason for the state during the manufacturing is that the developer accommodating member16is made deformable and reducible in order to facilitate assembling the developer accommodating member16with the frames17and18. In the case where the developer accommodating member16is not provided with the sheet-like air permeable portion16b, the size thereof cannot be changed from that in a state in which the developer accommodating member16is filled with the developer (the bag is closed) and therefore the developer accommodating member16is not readily deformed. For that reason, it takes time to assembly the developer accommodating member16and the step is complicated. Therefore, when the air permeability is imparted to at least a part of the developer accommodating member16, the size of the developer accommodating member16can be changed from that in the state in which the developer accommodating member16is filled with the developer and then is closed, thus facilitating the assembling of the developer accommodating member16.

Next, the reason for the states during the transportation and during the storage is that the developer accommodating member16can meet a change (difference) in air pressure between the inside and outside of the developer accommodating member16during the transportation and during the storage of the cartridge A. The difference in air pressure between the inside and outside of the developer accommodating member16is generated in the case where the developer accommodating member16is in a lower air-pressure environment during the transportation or the like than during the manufacturing or in the case where the developer accommodating member16is stored at a higher temperature than during the manufacturing. For that reason, by expansion of the developer accommodating member16, there is a possibility that parts contacting the developer accommodating member16are deformed or broken. Therefore, there is a need to control the air pressure and the temperature during the transportation and during the storage, so that facilitates for that purpose are required and a cost is increased. However, problems caused due to the difference in air pressure between the inside and outside of the developer accommodating member16can be solved by partly imparting the air permeability to the developer accommodating member16.

Further, in the case where the nonwoven fabric is provided with the discharging portion35and bonding portions22(22a,22binFIG. 4) at a periphery of the discharging portion35, there is a possibility that fibers of the nonwoven fabric fall out with peeling of the sealing member19during unsealing and then enter the developer to adversely affect the image. For that reason, the discharging portion35is provided to the molded portion16adifferent from the sheet-like air permeable portion16bhaving the air permeability, so that the above-described falling-out of the fibers from the nonwoven fabric is prevented. Further, a filling density can be increased by filling the developer while deaerating the developer accommodating member bag16.

(Structure of Discharging Portion of Developer Accommodating Member)

As shown inFIG. 10, the developer accommodating member16includes the discharging portion35. The discharging portion35is provided at the molded portion16aand includes the openings35aand the connecting portions35b. The openings35aare provided at a plurality of positions of the discharging portion35of the developer accommodating member16and are configured to permit the discharge of the inside developer. The connecting portions35bconnect the plurality of openings35aand define an outer configuration of the developer accommodating member16.

Further, the discharging portion35is continuously surrounded by the bonding portion22to be bonded in an unsealable state, so that the developer accommodated in the developer accommodating member16is sealed with the sealing member19.

(Structure of Bonding Portion of Developer Accommodating Member)

The bonding portion22has a rectangular shape consisting of two lines extending in a long direction (arrow F direction) and two lines extending in a short direction (arrow E direction) so as to surround the discharging portion35and therefore the bonding portion22enables the sealing of the discharge portion35.

Here, of the two lines of the welded bonding portion22extending in the long direction (arrow F direction), a bonding portion which is first unsealed is referred to as a first bonding portion22aand a bonding portion which is unsealed later is referred to as a second bonding portion22b. In this embodiment, in the case where the bonding portion22is viewed along the surface of the sealing member19, a bonding portion closer to a fold-back portion19d(FIG. 12) (or engaging portion19b) described later is the first bonding portion22a. Further, a bonding portion opposing the first bonding portion22avia the opening35ais the second bonding portion22b. Further, a bonding portion with respect to a widthwise direction (arrow E direction) is a widthwise bonding portion22c.

In this embodiment, an unsealing direction is the arrow E direction. The unsealing direction is defined as follows. In the case where the unsealing is effected by moving the sealing member19, of the first bonding portion22aand the second bonding portion22bopposing to each other via the openings35a, the first bonding portion22ais first unsealed (peeled). Thus, a direction directed from the first bonding portion22ato be first unsealed toward the second bonding portion22bis the unsealing direction (arrow E direction).

When the sealing member19is unsealed (peeled) from the developer accommodating member16in the arrow E direction, in some cases, the peeling microscopically progresses also in the arrow F direction due to the deformation of the developer accommodating member16by an unsealing force also in the first bonding portion22aand in the second bonding portion22b. However, the unsealing direction in this embodiment does not refer to such a microscopic unsealing direction.

(Disposition of Openings of Developer Accommodating Member)

Next, disposition of the openings35awill be described with reference toFIGS. 10,11and30. The movement direction (in which the sealing member19is pulled by the rotatable member20) of the sealing member19for sealing the openings35aand for exposing the openings35aby being moved is an arrow D direction. By the movement of the sealing member19, the exposure of the openings35aprogresses in the unsealing direction (arrow E direction). In the following, the movement direction of the sealing member19is the arrow D direction. The plurality of openings35aand the plurality of connecting portions35bare alternately disposed along the arrow F direction (FIG. 10) perpendicular to the unsealing direction (arrow E direction). Further, the sealing member19is configured to be wound up by rotating the rotatable member20but the arrow F direction is the same direction as an axis (shaft) of the rotatable member20.

The reason why the rotational axis direction of the developing roller13and the arrow F direction in which the plurality of openings35aare arranged are and made equal is that the developer is easily supplied, during the discharge thereof, to the developing roller13over the entire longitudinal direction without being localized.

The plurality of openings35aare shifted and disposed along the arrow F direction and therefore the discharging portion35is long in the arrow F direction and is short in the arrow E direction. That is, with respect to the arrow F direction, a distance from an end to another end of the plurality of openings35ais longer than that with respect to the arrow E direction.

Thus, the discharging portion35where the plurality of openings35aare shifted and disposed in the rotational axis direction (arrow F direction) perpendicular to the unsealing direction (arrow E direction) is long in the arrow F direction and is short in the arrow E direction. For that reason, the distance required for the unsealing can be made shorter than that required for the unsealing in the long direction (arrow F direction) and therefore a time required for the unsealing can also be made short.

Further, a constitution in which the sealing member19for covering the discharging portion35is wound up by the rotatable member20is employed. The rotational axis direction of the rotatable member20and the arrow F direction substantially perpendicular to the unsealing direction (arrow E direction) are made equal, so that winding distance and time of the sealing member19can be shortened.

(Shape and Direction of Openings of Developer Accommodating Member)

Each of the plurality of openings35ain this embodiment has a circular shape. When a discharging property is taken into consideration, an area of the openings35amay preferably be large. Further, the connecting portions35bdefining the openings35amay preferably be large (thick) in order to enhance the stiffness of the developer accommodating member16. Therefore, the area of the openings35aand the area of the connecting portions35bare required to achieve a balance in view of a material and a thickness of the discharging portion35and a force relationship with peeling strength during the unsealing described later and may be appropriately selected. The shape of each opening35amay also be, in addition to the circular shape, a polygonal shape such as a rectangular shape, an elongated circular shape, and the like shape.

The arrangement of the openings35amay only be required to be such that the openings35aare shifted (spaced) with respect to the arrow F direction perpendicular to the unsealing direction (arrow E direction). Constitutions shown in (a) and (b) ofFIG. 28may be carried out but the present invention is not limited thereto. Even when the adjacent openings35aoverlap with each other, as shown in (c) ofFIG. 28, as seen in the arrow F direction perpendicular to the unsealing direction (arrow E direction) or do not overlap with each other, as shown in (d) ofFIG. 28, as seen in the arrow F direction, an effect of the connecting portions35bdescribed later is achieved.

Further, the direction of the openings35amay preferably be such that the developer accommodated in the developer bag16is easily discharged in an attitude during image formation. For that reason, in the attitude during image formation, the openings35aare disposed so as to be open downward with respect to the gravitational direction. The state in which the openings35aopen downward with respect to the gravitational direction refers to that the direction of the openings35ahas a downward component with respect to the gravitational direction.

(Fixing Between Developer Accommodating Member and Frame)

With reference toFIGS. 3 and 4, the following constitution will be described. As shown inFIGS. 3 and 4, the developer accommodating member16is fixed inside the frame17and the frame18by the two types of fixing portions16dand16e.

First, as a first fixing portion, the first fixing portion16dof the developer accommodating member16where a force is received when the sealing member19is unsealed (removed) from the developer accommodating member16as described later is provided. The first fixing portion16dis provided at a plurality of positions in parallel to the arrow F direction along which the plurality of openings35aare arranged. Different from the arrangement at the plurality of positions, the first fixing portion16dmay also be a single fixing portion elongated in parallel to the arrow F direction (not shown).

The first fixing portion16dis positioned in the neighborhood of the openings35aof the developer accommodating member16.

The first fixing portion16dof the developer accommodating member16is fixed to a first fixing portion18aof the frame18.

The first fixing portion16dis a fixing portion necessary for the time of unsealing the developer accommodating member16, and its action and arrangement will be described later in the description of the unsealing.

Further, as a second fixing portion, the second fixing portion16efor preventing movement of the developer accommodating member16downward or toward the developing roller13and the developer supplying roller23is provided.

The second fixing portion16eis provided for the following two reasons. A first reason is that the second fixing portion16eof the developer accommodating member16is prevented from moving the developer accommodating member16downward in the attitude during the image formation. For that reason, the second fixing portion16emay preferably be disposed at an upper position in the attitude during the image formation.

Further, a second reason is that the developer accommodating member16is prevented from disturbing the image in contact with the developing roller13and the developer supplying roller23during the image formation. For that reason, the second fixing portion16eof the developer accommodating member16may preferably be provided at a position remote from the developing roller13and the developer supplying roller23. In this embodiment, the second fixing portion16eof the developer accommodating member16is disposed at an upper position remote from the developing roller13as shown inFIG. 4.

The second fixing portion16eof the developer accommodating member16is fixed to a second fixing portion18bof the frame18.

<Fixing Method Between Developer Accommodating Member and Frame>

(Fixing Method of First Fixing Portion)

Parts (a) to (d) ofFIG. 27are sectional views for illustrating a step for fixing the developer accommodating member16to the frame18. As a fixing method of the first fixing portion16dof the developer accommodating member16, fixing by ultrasonic clamping such that a boss of the second frame18is passed through the hole of the developer accommodating member16to be deformed is used. As shown in (a) ofFIG. 27, before fixing, the first fixing portion18aof the frame18has a cylindrical boss shape, and the first fixing portion16dof the developer accommodating member16has a hole which is open. An assembling step is described below.

First, as shown in (b) ofFIG. 27, a projected portion of the first fixing portion18aof the second frame18is passed through the hole of the first fixing portion16dof the developer accommodating member16.

Then, as shown in (c) ofFIG. 27, an end of the first fixing portion18aof the frame18is fused by a ultrasonic clamping tool91.

Then, as shown in (d) ofFIG. 27, the end of the first fixing portion18aof the frame18is deformed so that it is larger than the hole of the first fixing portion16dof the developer accommodating member16, and thus the developer accommodating member16is fixed to the frame18.

(Fixing Method of Second Fixing Portion)

As shown inFIG. 4, as a fixing method of the second fixing portion16eof the developer accommodating member16, clamping by the two frames17and18is used. Holes are made in the developer accommodating member16to constitute the first fixing portion16eof the developer accommodating member16, and projections are provided to the second frame18to constitute the second fixing portion18bof the frame.

An assembling step is as follows. Projections of the second fixing portions18bof the frame18are passed through the second fixing portions16eof the developer accommodating member16, and then the developer accommodating member16is clamped by the frame17so that the second fixing portions16e(holes) of the developer accommodating member16are not disengaged (dropped) from the projections to be fixed.

Incidentally, the developer accommodating member16is formed by the vacuum molding, and therefore the developer accommodating member16itself will keep its shape and the developer accommodating member16has a shape along the frames, so that the developer accommodating member16is supported by the frames as a whole. Therefore, it is possible to omit the second fixing portion for preventing (limiting) the movement of the developer accommodating member16toward the supplying roller23and the developing roller13as described in this embodiment.

As other fixing means, different from the above-described ultrasonic clamping, it is also possible to use fixing means using ultrasonic wave. For example, heat clamping using heat, (heat) welding or ultrasonic welding for directly welding the developer accommodating member16to the frame17or the frame18, bonding using a solvent or an adhesive, insertion of the developer accommodating member16between the frames, hooking using the heat clamping, the ultrasonic clamping, a screw, or a combination of holes and projections (such as bosses), and the like means may also be used. Further, the developer accommodating member16may also be fixed via a separate member provided between the frames17and18depending on appropriate design based on relationships in space, arrangement or the like between the developer bag16and the frames17and18(not shown).

As shown inFIGS. 3 and 4, the sealing member19covers the discharging opening35of the developer accommodating member16before use of the cartridge A, thus confining the developer in the developer accommodating member16. The sealing member19is moved, so that the openings35aare exposed. The sealing member19is constituted by a sheet-like sealing member including a sealing portion19afor covering (sealing) the discharge portion35of the developer accommodating member16, an engaging portion19bto be fixed (engaged) with the rotatable member20described later, and a connecting portion19cwhich connects the sealing portion19aand the engaging portion19b. The sheet-like sealing member is formed of a laminate material having a sealant layer which exhibits an easy-unsealing property described later, and a base material therefor is polyethylene telephthalate (PET), polyethylene, polypropylene or the like. A thickness of the sheet-like sealing member may appropriately be set in a range of 0.03-0.15 mm.

(Sealing Portion of Sealing Member)

A sealing portion19arefers to a region where the sealing member19seals the plurality of openings35aand connecting portions35bof the developer accommodating member16. By the sealing portion19a, the developer is prevented from being leaked from the inside of the developer accommodating member16until before use of the cartridge A.

(Engaging Portion of Sealing Member)

The sealing member19has a free end portion in one end side thereof with respect to the unsealing direction (arrow E direction), and at the free end portion, the engaging portion19bto be engaged with the rotatable member20for moving the sealing member19is provided. The engaging portion19bas an end portion of the sealing member19for exposing the openings35ais engaged with the rotatable member20. The sealing member19may also be configured to be automatically subjected to the unsealing (pealing) by receiving a driving force from the image forming apparatus main assembly B. Or, the sealing member19may also be configured to be subjected to the unsealing (peeling) by being held and moved by the user. In this embodiment, the rotatable member20is a rotation shaft provided in the frame, and the sealing member19engaged with the rotatable member20is pulled, so that the developer accommodating member16accommodating the developer is unsealed.

(Connecting Portion of Sealing Member)

A portion connecting the bonding portion22and the engaging portion19bis the connecting portion19c(FIG. 3). The connecting portion19cis a portion for transmitting a force so as to pull off the bonding portions22(22a,22b) by receiving the force from the rotatable member20.

Referring toFIG. 12, a plane formed between the first bonding portion22aand the second bonding portion22bat the movement of the unsealing is taken as N1. A plane which is perpendicular to the plane N1and which passes through the first bonding portion22ais taken as N2.

The rotatable member20is disposed closer to the second bonding portion22bthan the plane N2passing through the first bonding portion22a. In other words, the sealing member19includes when it is seen along the surface of the sheet-like sealing member19, a fold-back portion19dwhere the sealing member19is folded back at the portion (connecting portion19c) between the connecting portion22and the engaging portion19bengaged with the rotatable member20. The fold-back portion19dmay be provided with or not provided with a fold (crease). A folding angle Q of the sealing member19may preferably be 90 degrees or less. The folding angle Q is an angle Q between a plane of the bonding portion22of the developer accommodating member16and a plane along the arrow D direction in which the sealing member19is pulled.

Further, fixing between the sealing member19and the rotatable member20is, in this embodiment, made by the ultrasonic clamping similarly as in the case of the first fixing portion16d. Other than the ultrasonic clamping, the fixing may also be made by the (heat) welding, the ultrasonic welding, the bonding, the insertion between the frames, the hooking by a hole and a projection, or the like similarly as the means for fixing the first fixing portion16dand the second fixing portion16e.

(Portion Having Easy-Unsealing Property of Sealing Member)

A method of providing a peeling force of the bonding portion22with a desired value will be described. In this embodiment, in order to provide the peeling force with the desired value (a minimum force within a range in which the toner sealing property can be maintained), two methods are principally employed.

In a first method, a laminate material having a sealant layer for enabling easy unsealing of the sealing member is applied. Further, the first method is a method in which the easy unsealing is enabled at the bonding portion by using, as the material for the developer accommodating member16, a sheet material (of, e.g., polyethylene or polypropylene) which is weldable with the sealant layer and which has flexibility. By changing a combination of formulation of the sealant layer with the material to be bonded, the peeling force can be adjusted correspondingly to a desired condition. In this embodiment, a material having a peeling strength of about 3N/15 mm measured by testing methods for heat sealed flexible packages (JIS-Z0238) is used.

A second method is a method in which as shown inFIGS. 4 and 7, the discharging portion35of the developer accommodating member16is placed in a state in which the sealing member19is folded back with respect to an unsealing direction (arrow E direction). For example, in the state ofFIG. 4, the rotatable member20is rotated in the rotational direction (arrow C direction), so that the sealing member19is pulled in a pulling direction (arrow D direction) by the rotatable member20. As a result, the developer accommodating member16and the sealing member19provide an inclined peeling positional relationship, as shown inFIG. 12, in which the angle Q between the plane of the bonding portion22of the developer accommodating member16and the plane along the pulling direction (arrow D direction) of the sealing member19is 90 degrees or more. It has been conventionally known that the peeling force necessary to separate the both surfaces can be reduced by establishing the inclined peeling positional relationship. Therefore, as described above, the discharging portion35is placed in the state in which the sealing member19is folded back with respect to the unsealing direction (arrow E direction), so that the sealing member19of the bonding portion22and the developer accommodating member16are placed in the inclined peeling positional relationship and thus the peeling force can be adjusted so as to be reduced.

The rotatable (unsealing) member20is used for the purpose of peeling the sealing member19from the developer accommodating member16by applying a force to the sealing member19to move the sealing member19. The rotatable member20includes a supporting portion (not shown) which has a shaft shape and which is rotatably supported by the second frame18at its ends, and includes an engaging portion20bto which the engaging portion19bof the sealing member19. In this embodiment, the rotatable member20has a rectangular shaft shape, and the engaging portion19bof the sealing member19is engaged with the engaging portion20bat one of four sides of the rectangular shaft.

(Combined Use as Unsealing Member, Urging Member and Stirring Member)

The urging sheet21for externally acting on the developer accommodating member16to discharge the developer accommodated in the developer accommodating member16, and the rotatable member20may be separate members but in this embodiment, the same part performs functions of the rotatable member20and the urging sheet21.

Further, a function of stirring the developer discharged from the developer accommodating member16and a function of the rotatable member20may be performed by separate members but in this embodiment, the rotatable member20also perform the stirring function of the stirring member.

(Effect of Combined Use as Unsealing Member, Urging Member and Stirring Member)

Thus, by using the same part (member) as the rotatable member20, the urging sheet21and the stirring member, the number of parts is reduced, so that it becomes possible to realize cost reduction and space saving.

<Summary of Unsealing of Developer Accommodating Member (Bag)>

The unsealing of the developer accommodating member (developer accommodating bag)16will be described with reference toFIGS. 7 and 8.

For unsealing the developer accommodating member16, the developer accommodating unit25includes a power application point portion20awhere the rotatable member20applies the force for pulling the sealing member19, and includes the fixing portion18aof the frame for fixing the developer accommodating member16to be pulled.

The power application point portion20ais a portion, closest to the bonding portion22, of a portion where the sealing member19and the rotatable member20contact at the moment of the unsealing. In (b) ofFIG. 7, a corner portion20cof the rotatable member20constitutes the power application point portion20a. The fixing portion18aof the frame18includes a fixing portion18cfor suppressing movement of the developer accommodating member16caused by the force during the unsealing. In this embodiment, from the bonding portion22, the first fixing portion18aof the frame18and the first bonding portion16dof the developer accommodating member16are bonded to each other by the ultrasonic clamping. As shown in (b) and (c) ofFIG. 7and (a) ofFIG. 8, a portion, closer to the bonding portion22, of the first fixing portion18abonded by the ultrasonic clamping constitutes the fixing portion18c.

As shown inFIG. 4, the rotatable member20is rotated in the arrow C direction by transmission of the during force thereto by an unshown driving means provided to the apparatus main assembly B.

A state immediately before the sealing member19is pulled by further rotation of the rotatable member20to start the unsealing is shown inFIG. 5and (c) ofFIG. 7. With the rotation, the sealing member19fixed to the rotatable member20by the engaging portion19bis pulled in the arrow D direction by the corner portion20c(power application point portion20a) of the rectangular rotatable member20.

When the sealing member19is pulled, the developer accommodating member16is pulled via the bonding portion22. Then, a force is applied to the first fixing portion16dof the developer accommodating member16, so that the developer accommodating member16is pulled from the fixing portion18ctoward the power application point portion20bby the fixing portion18c. Then, in a cross section perpendicular to the rotation shaft of the rotatable member20, the first bonding portion22ais moved to approach a line connecting the power application point portion20aand the fixing portion18c. At this time, with respect to the arrow D direction, from a side close to the rotation shaft of the rotatable member20, the portions are disposed in the order of the openings35a, the first bonding portion22a, the fold-back portion19dand the fixing portion18c((b) ofFIG. 7). Further, the unsealing member19is folded back between the first bonding portion22aand the engaging portion19band therefore the force is applied to the portion of the first bonding portion22aso as to be inclination-peeled in the arrow D direction. Then, the peeling of the first bonding portion22ais effected to start the unsealing of the discharging portion35.

Together with the corner portion20c, also the power application point portion20ais moved in the arrow C direction, and when the sealing member contacts a corner portion20d, the power application point portion20ais moved from the corner portion20cto the corner portion20d. Part (b) ofFIG. 7shows a state in which the power application point portion20ais the corner portion20c, and (c) ofFIG. 7shows a state in which the rotatable member20in further rotated and thus the power application point portion20ais moved to the corner portion20d.

As shown inFIG. 6and (c) ofFIG. 7, when the unsealing is advanced with further rotation of the rotatable member20, also the fold-back portion19dis moved in the arrow E direction. Then, the unsealing is further advanced, so that the openings35aare exposed. A state in which the peeling of the second bonding portion22bis to be started after the openings35aare exposed is shown in (a) ofFIG. 8. Also at this time, similarly as in the case of the peeling of the first bonding portion22a, the sealing member19is pulled toward the power application point portion20a, and the developer accommodating member16stands firm toward a direction of the fixing portion18c(an arrow H direction). Then, in a cross section perpendicular to the rotation shaft of the rotatable member20, the second bonding portion20bis moved to approach a line connecting the power application point portion20aand the fixing portion18c. Then, the force is applied to the portion of the bonding portion22bin the arrow D direction, so that the second bonding portion22bis separated. Thus, the second bonding portion222bis peeled to complete the unsealing ((b) ofFIG. 8andFIG. 9). Then, the developer inside the developer accommodating member16is discharged in an arrow I direction through the openings35aof the discharging portion35.

Thus, the sealing member19is wound up around the rotatable member20by the rotation of the rotatable member20, so that the bonding portion22is unsealed. The sealing member19is wound up by the rotation of the rotatable member20, and therefore a space required to move the rotatable member20may only be required to be a rotation space of the rotatable member20, and compared with the case where the sealing member19is moved by movement other than the rotation, it is possible to realize space saving.

By providing the sealing member19with the fold-back portion19d, so that the bonding portion22can be inclination-peeled without using shearing peeling and thus can be unsealed with reliability.

Further, the engaging portion19b, to be engaged with the rotatable member20, for unsealing the sealing member19in an end side of the sealing member19with respect to a direction substantially perpendicular to the arrow F direction in which the plurality of openings35aare arranged is provided, so that the sealing member19can be engaged and unsealed with reliability.

Further, by providing the frame with the fixing portion18c, the developer accommodating member16is supported by the frame during the unsealing, so that even a soft and deformable developer accommodating member16becomes unsealable with reliability.

With respect to the discharge of the developer during the unsealing, as described above, the bonding portion22is moved along the line connecting the power application point portion20aand the fixing portion18c(in the order of (a) ofFIG. 7, (b) ofFIG. 7, (c) ofFIG. 7and (a) ofFIG. 8). By this motion, the developer at the periphery of the openings35ais moved, so that agglomeration of the developer can be broken.

(Positional Relation of Fixing Portion Associated with Unsealing)

As shown inFIG. 4, in order to peel off the first bonding portion22bwith reliability, the following positional relation is required between the first bonding portion22band the fixing portion18c. During the unsealing, with respect to the fixing portion18c, the rotatable member20pulls the sealing member19in the arrow D direction. At this time, with respect to the movement direction (arrow D direction) of the sealing member19by the rotatable member20, the fixing portion18cis provided upstream of the openings35a. For that reason, a force is applied to the fixing portion18cin the arrow H direction. Therefore, when the unsealing force is applied, the sealing member19is pulled in the arrow H direction and the arrow D direction between the fixing portion18cand the rotatable member20to apply a force to the first bonding portion20a, thus advancing the unsealing. Thus, when the fixing portion18cis not provided upstream with respect to the movement direction (arrow D direction) of the sealing member19, the entire developer accommodating member16is pulled in the direction in which the sealing member19is pulled, so that the force cannot be applied to the first bonding portion22aand thus the first bonding portion22acannot be unsealed.

In this way, the fixing portion18cis provided upstream with respect to the movement direction (arrow D direction) of the sealing member19, so that reliable unsealing becomes possible.

(Distance Relation of Fixing Portion Associated with Unsealing)

As shown inFIGS. 22 and 23, in order to peel off the first bonding portion22awith reliability, the following length relationship is required between the first bonding portion22aand the fixing portion18c. First, a point of the first bonding portion22afinally peeled off when a flat plane which passes the rotatable member20, the openings35aand the fixing portion18cand which is perpendicular to the rotation shaft of the rotatable member20is viewed, is taken as a first point22d. The first point22dis an end point of the first bonding portion22aclose to the openings35a. A distance from the fixing portion18cto the first point22dalong the developer accommodating member16is taken as M1. A distance, from the first fixing portion18cto the first point22d, measured along the developer accommodating member16with respect to the direction including the openings35ais taken as M2. The openings35aprovide a space in which the material for the developer accommodating member16is not present but a width of the openings35ais also included in the distance M2.

In this case, a relationship of M1<M2is satisfied to permit the peeling-off of the first bonding portion22a. The relationship of M1<M2will be described specifically.
(M1<M2)

First, in the case where M1<M2is satisfied, as shown inFIG. 22, a force for pulling the sealing member19toward the first bonding portion22a(in the arrow D direction) by the rotatable member20and a retaining force of the fixing portion (in the arrow H direction) are applied to the first bonding portion22a, so that inclination peeling of the first bonding portion22acan be effected. By effecting the inclination peeling, the peeling force can be set at a low level. Part (a) ofFIG. 22shows a state before the unsealing, and (b) ofFIG. 22shows a state immediately before the first bonding portion22ais unsealed.
(M1>M2)

On the other hand, in the case of M1>M2, as shown inFIG. 23, the pulling force by the rotatable member20is not applied to the first bonding portion22abut is applied to the second bonding portion22b. In this case, the force is not applied to the first bonding portion22aand therefore the first bonding portion22ais not peeled. In this case, the force from the rotatable member20(in the arrow D direction) and the retaining force of the fixing portion18c(in the arrow H direction) are applied to the second bonding portion22b. In this state, to the second bonding portion22b, the force for pulling the sealing member19by the rotatable member20(in the arrow D direction) and the retaining force of the fixing portion18c(in the arrow H direction) are applied. At the portion of the second bonding portion22b, the peeling relationship is a shearing peeling relationship and therefore it is difficult to unseal the second bonding portion22b. This is because the shearing peeling requires a large force compared with the inclination peeling.

Part (a) ofFIG. 23shows a state before the unsealing, and (b) ofFIG. 23shows a state when the force for pulling the sealing member19by the rotatable member20(in the arrow D direction) is applied to the bonding portion (the second bonding portion in this case) by the rotation of the rotatable member20. To the second bonding portion22b, the force is applied but is applied based on the shearing peeling and therefore compared with the case of the inclination peeling, a very large force is required, so that it becomes difficult to reduce the peeling force.

(Distance in Case where Projection is Present)

Definition of a manner of measuring the above-described distances M1and M2will be described. The distances M1and M2are important when the sealing member19is pulled during the unsealing. In the case where there is no projection (projected connecting portion)16tat an intermediate position of paths of M1and M2, the distances developed as shown inFIGS. 22 and 23may only be required to be measured. Further, in the case where there is the projection16tformed, by bonding in manufacturing, at the intermediate position of the paths of M1and M2, even when the sealing member19is pulled during the unsealing, the projection16tis not elongated (peeled off) and therefore the portion of the projection16tis not included in the distances M1and M2. That is, the portion, such as the projection16t, which does not affect transmission of the force is not included in the distances M1and M2.

As described above, based on the relationship of M1<M2, the first bonding portion22ais unsealed earlier than the second bonding portion22b. As a result, the fold-back portion19dof the sealing member19is provided closer to the first bonding portion22a. By this fold-back portion19d, the peeling is not the shearing peeling but is the inclination peeling. As a result, with reliability, the sealing member19can be peeled off from the developer accommodating member16, so that it is possible to provide an unsealable developer accommodating unit25.

A relation between a plurality of fixing portions and the unsealing will be described with reference to (a) and (b) ofFIG. 31, wherein (a) ofFIG. 31shows a state before the unsealing, and (b) ofFIG. 31shows a state immediately before the rotatable member20is rotated from the state of (a) ofFIG. 31to unseal the first bonding portion22a. In this embodiment, the first fixing portion18aand the second fixing portion18bare provided. The force during the unsealing is applied to the first fixing portion18adisposed at a place close to the first bonding portion22a, which is first unsealed, spaced from the second bonding portion22bvia the openings35a. For that reason, the second fixing portion18bis not required to be taken into consideration in the measuring manners of the distances M1and M2described above. Thus, in the case there are the plurality of fixing portions, the unsealing is effected on the basis of the fixing portion disposed at the place close to the first bonding portion22a, which is first unsealed via the openings35ato which the force during the unsealing is to be applied.

(Positional Relation of Second Bonding Portion)

With reference toFIG. 12showing a state immediately before the first bonding portion22ais unsealed, an arrangement in which the second bonding portion22bcan be more satisfactorily unsealed without being wound up around the rotatable member20will be described. First, an end portion of the first bonding portion22aremote from the openings35ais taken as a second point22e. An end portion of the second bonding portion22bremote from the openings35ais taken as a third point22f. A distance from the second point22eto the third point22fis taken as L1. A distance from the second point22eto the power application point portion20ais taken as L2. In this case, the distances L1and L2are required to satisfy the relationship of L1<L2.

This is because in the case where L1is larger than L2, the second bonding portion22breaches the power application point portion22abefore the peeling of the second bonding portion22bis ended, and thus the second bonding portion22bis wound about the rotatable member20. Therefore, the force cannot be applied so as to peel off the sealing member19from the second bonding portion22b. For that reason, it becomes difficult to unseal the sealing member19from the developer accommodating member16.

As described above, the relationship between the distance L1and L2is made to satisfy: L1<L2, so that the sealing member19is satisfactorily unsealable without being wound about the rotatable member20.

(Function of Connecting Portions Defining Openings)

A summary of the connecting portions35b, defining the openings35a, which perform a large function in the unsealing operation of the developer accommodating member16will be described.

FIG. 11is a schematic view of the discharging portion35when the peeling at the first bonding portion22ato be first unsealed is ended to expose the openings35a, and shows a state in which the peeling at the second bonding portion22bis not ended. As described above, the discharging portion35includes the plurality of openings35ashifted and disposed along the direction (arrow F direction) perpendicular to the unsealing direction (arrow E direction) in which the exposure of the openings35ais advanced. For that reason, also the portion connecting portions35bdefining the plurality of openings35aare disposed along the arrow F direction. As a result, the portion connecting portions35bconnect the first bonding portion22aand the second bonding portion22bwith respect to the unsealing direction (arrow E direction) of the openings35a. For that reason, at the time of the state of (a) ofFIG. 8in which the unsealing of the first bonding portion22ais ended, the force for unsealing the second bonding portion22bcan be received by the first fixing portion16dvia the connecting portions35b, so that the force for peeling off the sealing member19from the developer accommodating member16can be transferred. That is, the forces are applied to the second bonding portion22bin the arrow D direction and the arrow E direction, so that also at the second bonding portion22b, the sealing member19is peelable.

A similar effect can be obtained also in cases other than the case where the openings35aare arranged in the direction (arrow F direction) perpendicular to the unsealing direction (arrow E direction) as shown in (b) ofFIG. 28as described above. Even when the openings35aare not completely arranged in the direction perpendicular to the unsealing direction (arrow E direction) as shown in (c) ofFIG. 28, the connecting portions35bcan transmit the force, for peeling off the sealing member19from the developer accommodating member16, in an arrow P direction. Further, even when the openings35overlap each other with respect to the unsealing direction (arrow E direction) as shown in (d) ofFIG. 28, the connecting portions35bcan transmit the force, for obliquely peeling the sealing member19from the developer accommodating member16, in an arrow P direction. That is, the plurality of openings35amay only be required to be shifted and disposed with respect to the arrow F direction perpendicular to the unsealing direction (arrow E direction).

Further, as shown in (b) ofFIG. 28, a portion including the connecting portions35bprovided at a periphery of the openings35amay also be used as the bonding portion22. Also in this case, by the presence of the connecting portions35b, the force can be transmitted until the sealing member19is completely peeled off at the bonding portion22, so that the unsealing is effected with reliability.

As for a relationship between the rotation shaft of the rotatable member20and the openings35a, it can be said that the openings35aare shifted and disposed in the direction (arrow F direction) of the rotation shaft of the rotatable member20. As a result, the connecting portions35bfor connecting the first and second bonding portions22aand22bwith respect to the direction (the arrow E direction) perpendicular to the rotation shaft of the urging member20is provided. The openings35amay only be required to be shifted and disposed in the rotational axis direction (indicated by the arrow F) of the unsealing member. Even when the openings35aoverlap with each other with respect to the rotational axis direction (indicated by the arrow F) as shown in (b) ofFIG. 28and do not overlap with each other completely with respect to the rotational axis direction (indicated by the arrow F) as shown in (d) ofFIG. 28, the force can be transmitted in the arrow P direction and thus the effect of the connecting portions35bcan be achieved.

Thus, by the presence of the connecting portions35bfor connecting the first and second bonding portions22aand22bat the discharging portion35, the developer accommodating member16accommodating the developer can transmit the unsealing force of the rotatable member20until the second bonding portion22bis unsealed, so that the discharging portion35can be unsealed with reliability.

A relationship between the openings35aand the engaging portion19bof the sealing member19will be described (FIG. 3). The engaging portion19bis provided in an end side of the sealing member19with respect to the direction substantially perpendicular to the direction in which the plurality of openings35aare arranged.

A relationship between the openings35aand the rotatable member20will be described (FIG. 3). The rotatable member20is provided in an end side of the sealing member19with respect to the direction substantially perpendicular to the direction in which the plurality of openings35aare arranged.

Also in such a constitution, it is possible to obtain the effect of transmitting the unsealing force of the rotatable member20by the connecting portions35buntil the second bonding portion22bis unsealed.

(Example of Connecting Portions as Separate Member)

The connecting portions35bdefining the openings35amay also be provided as a separate member (connecting members16f) as shown inFIG. 21. In this case, a constitution in which a single long opening116aelongated in the arrow F direction perpendicular to the unsealing direction (arrow E direction) and then the connecting members16fas the separate member connecting both sides of the opening116aalong the unsealing direction (arrow E direction) are provided on the opening16ais employed. At this time, the connecting members16fare bonded in each of the first bonding portion22aside and the second bonding portion22bside of the opening116aby adhesive bonding, welding or the like.

Also in the case where the developer accommodating member16is provided with the connecting members16f, the sealing member19is folded back between the bonding portion22and the engaging portion18bas described above and is wound around the rotatable member20, so that the flexible container16is unsealable. By employing such a constitution, the connecting portions35bdefining the openings35ain the case where the plurality of openings35aare provided, and the connecting members16fperform the same function. That is, the single long opening116ais the same as the plurality of openings35aby providing the connecting members16f.

Therefore, when the sealing member19is peeled at the second bonding portion22bafter the unsealing of the first bonding portion22ais ended, the force (arrow D direction) during the unsealing of the second bonding portion22bby the rotatable member20can be received by the first fixing portion16dvia the connecting members16fwith respect to the arrow H direction. Thus, the force for peeling the sealing member19from the developer accommodating member16can be transmitted. That is, the forces are applied to the second bonding portion22bin the arrow D direction and the arrow H direction, so that also the second bonding portion22bis unsealable.

In this way, the single long opening116ais combined with the connecting members16fto form the plurality of openings35a, so that it also becomes possible to increase the stiffness of only the connecting members16f.

(Problem of Unsealing Property in Case of No Connecting Portion)

An example in which the present invention is not applied and thus it is difficult to unseal the developer accommodating member16will be described. This is the case where there are no connecting portions35band thus it becomes difficult to unseal the developer bag16as shown inFIGS. 13 and 14. Parts (a) and (b) ofFIG. 13show an example in which there are no connecting portions35band a single long opening116ais provided. Part (a) ofFIG. 13shows a state before the peeling at the second bonding portion22b, and (b) ofFIG. 13andFIG. 15show a state when the sealing member19is peeled at the second bonding portion22b. Parts (a) and (b) ofFIG. 8are enlarged sectional views of the openings35aand their periphery in states before and after the sealing member19is peeled at the second bonding portion22bin this embodiment, and (a) to (c) ofFIG. 14are sectional views of the opening16aand its periphery in the case where there are no connecting portions35band thus it becomes difficult to unseal the developer bag16.

In this case, a state in which the unsealing is advanced to the second bonding portion22bis shown in (a) ofFIG. 14, and from this state, the sealing member19is pulled and moved in the arrow D direction by further rotation of the rotatable member20. Then, since there are no connecting portions35b, the force from the first fixing portion16dcannot be transmitted to the second bonding portion22bside at the central portion of the opening116a. For that reason, as shown in (b) ofFIG. 14and (b) ofFIG. 13, a binding force of the fixing portion18aof the frame to the second bonding portion22bis eliminated, so that the opening116agradually opens largely in the arrow D direction. Further, the second bonding portion22bis pulled by the sealing member19, so that the opening116ais deformed as shown in (c) ofFIG. 14. In this case, a force acting on the second bonding portion22bfails to provide the inclination peeling positional relationship as shown inFIG. 8and causes the shearing peeling (approximately 0-degree peeling) by the deformation of the opening16aas shown in (c) ofFIG. 14, so that there is a need to apply a large force for the peeling. In addition, the supporting force of the first fixing force16dcannot be transmitted to the second bonding portion22band therefore the second bonding portion22bis pulled by the rotatable member20without causing the peeling of the sealing member19therefrom. For that reason, the opening116ain the neighborhood of a longitudinal central portion of the second bonding portion22bfurther opens largely, so that the second bonding portion22bis wound about the rotatable member20.

Incidentally, when a developer accommodating member is a rigid structure, there is no such a deformation, so that the sealing member is unsealable as in the conventional example. However, in the case of a constitution in which the developer is accommodated in a soft deformation bag-like member and an opening which is deformed during unsealing is unsealed, as described above, when there are no connecting portions35b, it is difficult to effect the unsealing.

As described above, the sealing member19(toner seal) is made unsealable transmitting the driving force to the rotatable member20of the image forming apparatus100and thus there is no need for the user to peel off the toner seal, so that the developer accommodating unit25and the cartridge A can be simply and easily replaced and used. Further, the sealing member19after the unsealing is fixed to the rotatable member20, so that the unsealing can be effected without demounting a waste material from the cartridge A.

<Summary of Urging Member and Developer Discharge)

As shown inFIGS. 16 and 17, the urging sheet21is mounted on a surface of the rotatable member20which is rectangular in cross section. To the rotatable member20, the driving force is transmitted by the unshown driving means inside the apparatus main assembly B, and when the rotatable member20is rotated in the arrow C direction, the urging sheet21is rotated together with the rotatable member20in the arrow C direction. The urging sheet21is a flexible sheet formed of a material such as PET, PPS (polyphenylene sulfide) or polycarbonate, in a thickness of about 0.05-0.1 mm, and an end thereof projects to the outside of a circumscribed circle of the rotatable member20. In this embodiment, on different surfaces of the rotatable member20, the sealing member19and the urging sheet21are fixed but may also be fixed on the same surface of the rotatable member20. In the following, features will be described.

The developer accommodating member16is disposed at a part of the inner wall surface (in the upper region of the frames17and18). When the urging sheet21of the urging member500or the sealing member19urges the developer accommodating member16to increase the urging force acting on the developer accommodating member16against the frames17and18, the developer accommodating member16is pressed against the frames17and18to be contracted. When the urging force of the urging member500toward the developer accommodating member16is weakened, the developer accommodating member16is rebounded by the frames17and18to be expanded. Thus, the developer accommodating member16becomes small by being pressed against the frames17and18and becomes large by being rebounded by the frames17and18, so that the developer accommodating member16is efficiently contracted and expanded to facilitate the discharge of the developer G from the openings35a.

The urging member500changes the position of the opening-containing side X by urging the developer accommodating member16. This is because the developer G is discharged from a portion thereof at a periphery of the openings35aand thus the change is position of the opening-containing side X most facilitates the discharge of the developer G.

The developer accommodating member16is formed so that a position between the plurality of surface portions is curved, and the urging member500urges the opening-containing side X. The developer G is discharged from the portion thereof at the periphery of the openings35aand thus when the position of the opening-containing side X is changed, the urging of the opening-containing side X most facilitates the discharge of the developer G.

The urging member500is rotatable provided in the frames17and18, and a distance from its rotation center to an outer edge thereof is different with respect to the circumferential direction when viewed from its cross section perpendicular to the rotation center thereof. Particularly, the cross-sectional shape of the rotatable member20is not a circle but may also be a polygon and this is also a point in that the distance from the rotation center to the outer edge is different with respect to the circumferential direction. Therefore, when the urging sheet21is rotated, the urging member500repeats such an operation that it pushes and pulls the developer accommodating member16.

The urging member500(particularly the urging sheet21or the sealing member19) is capable of stirring the developer G, inside the frames17and18, discharged from the developer accommodating member16and then is capable of feeding the developer G toward the supplying roller23and the developing roller13.

<Summary of Developer Discharge from Developer Accommodating Member (Bag)>

(Summary of Discharge from Before Unsealing to During Unseal)

First, the discharge of the developer from before the unsealing to the time of start of the unsealing will be described. As described above with reference toFIGS. 7 and 8, the sealing member19is pulled toward the power application point portion20a(in the arrow D direction), and the developer accommodating member16is supported by the fixing portion18c. For that reason, during unsealing, three places consisting of the power application point portion20a, the fixing portion18cof the frame and the place of the bonding portion22where the sealing member19is peeled are moved in a direction in which these three places are aligned in a rectilinear line in a cross section perpendicular to the rotation shaft of the rotatable member20. Thus, the position of the openings35ais changed between the time before the rotatable member20applies the force to the sealing member19to perform the unsealing operation and the time when the unsealing operation is started to unseal the first bonding portion22a, so that stagnation of the developer in the neighborhood of the openings35acan be prevented and thus a discharging property is good.

The openings35aformed to open downward with respect to the vertical direction. Before image formation, a part of the sealing member19of the urging member500closes the openings35a, and during the image formation, the part of the sealing member19opens the openings35a. The openings35aare formed to open downward, and therefore only by opening the openings35aby the sealing member19, the developer G is discharged from the developer accommodating member16by the gravitation. Thus, when the openings35aof the developer accommodating member16are unsealed, the developer in the neighborhood of the openings35ais readily discharged by the action of the gravitation of the developer itself and vibration of the developer accommodating member16, and the like.

After the unsealing, when the rotatable member20is further rotated, also the urging sheet21bfor urging the developer accommodating member16fixed to the rotatable member20is rotated, so that the urging sheet21is wound about the rotatable member20by the developer accommodating member16as shown inFIG. 9. As shown inFIG. 16, the urging sheet21has elasticity and therefore is likely to be restored to an original shape, thus urging the developer accommodating member16in an arrow J direction. At this time, the developer accommodating member16is urged by the urging sheet21and is pressed against the second frame18via the toner, so that the entire developer accommodating member16is deformed. The developer accommodating member16is urged by the urging sheet21to be decreased in its inside volume.

Thus, by the decrease in inside volume of and the change in entire shape of the developer accommodating member16, the developer inside the developer accommodating member16is stirred and as a result, the developer is readily discharged from the openings35a. At this time, the developer accommodating member16is closed except for the openings35aand thus there is no escape route except for the openings35a, and therefore the discharging property from the openings35ais high. By the discharging action as described above, the developer is readily discharged in the arrow I direction.

In the case, when the developer accommodating member16is contacted to and pressed against the second frame18at least at a part thereof, the developer accommodating member16is deformable.

By aligning the rotational axis direction of the developing roller13and the arrangement direction (arrow F direction) of the plurality of openings35a, the developer can be easily supplied over the entire longitudinal direction of the developing roller13during the discharge without being localized.

When the developer accommodating unit25is mounted in the image forming apparatus100, by providing the openings35aso as to open toward the direction of gravitation, the developer discharging property can be improved.

Further, the urging sheet21provided in the frames17and18urges the developer accommodating member16so as to be pressed against the frame18, so that the developer discharging property can be improved.

As shown inFIG. 17, the rotatable member20is further rotated, so that the urging sheet21bis separated from the developer accommodating member16. At this time, the developer accommodating member16has flexibility and therefore is likely to be restored to the state before the urging by the weight of the developer (arrow K direction). Then, also the sealing member19is rotated and urges the developer accommodating member16toward the frame18as shown inFIG. 16, so that the developer accommodating member16is deformed to move the developer at a position other than the neighborhood of the openings35aand thus the developer is discharged from the openings35a.

(Summary of Discharge/Repetition of Urging and Restoration)

In the case where the developer immediately after the unsealing is accommodated in the developer accommodating member16in a large amount, a penetration depth (entering amount) of the urging sheet21, the sealing member19and the rotatable member20with respect to the developer accommodating member16is repetitively changed, so that the developer accommodating member16is deformed so as to be pressed against the frame18. Contraction of the developer accommodating member16by the urging with the urging member21and restoration of the shape of the developer accommodating member16by the weight of the developer inside the developer accommodating member16and by the flexibility of the developer accommodating member16are repeated. Further, by the above-described action, the developer accommodating member16itself is moved and therefore the developer accommodating member16is vibrated, so that the developer inside the developer accommodating member16is discharged from the openings35aalso by the vibration of the developer accommodating member16. The urging sheet21is rotated and therefore is capable of repetitively urging the developer accommodating member16.

(Example in which Developer Accommodating Member is Applied to Frame)

A portion27where the developer accommodating member16is urged against the frame18is as shown inFIG. 25, even in the case where a bonding portion28such as an adhesive or a double-side tape is provided and bonds the developer accommodating member16to the second frame18, the urging sheet21bcan urge the developer accommodating member16to discharge the developer.

(Case where Amount of Developer is Small)

The case where the amount of the developer inside the developer accommodating member16is decreased by image formation will be described with reference to (a) and (b) ofFIG. 32. Immediately after the unsealing, as shown in (a) ofFIG. 32, while the urging sheet21contacts the developer accommodating member16, a size (inside volume) of the developer accommodating member16is periodically changed. However, when the amount of the accommodated developer becomes small, as shown in (b) ofFIG. 32, the weight of the developer becomes light, so that the flexible container16does not readily follow the urging sheet21and thus repeats periodical separation from and contact with the urging sheet21in some cases. For that reason, the size (inside volume) of the developer accommodating member16is not so changed. For that reason, a developer discharging effect by the change in inside volume of the developer accommodating member16is decreased but by the periodical contact between the developer accommodating member16and the urging sheet21, the developer accommodating member16is vibrated and thus the developer can be discharged.

(Combined Use as Urging Sheet and Sealing Member)

A single part may be used as the urging sheet21and the sealing member19to have functions of these members. After the unsealing, the bonding portion22is separated from the developer accommodating member16and therefore an end of the sealing member19in the bonding portion22side is a free end. For this reason, the sealing member19can have the function of the urging sheet21. Thus, the rotatable member20can have the function of the rotatable member20for the urging sheet21, and the sealing member19can have the function of the urging sheet21. As a result, it is possible to reduce the number of parts and thus cost reduction can be realized.

As described above, the developer inside the developer accommodating member16can be satisfactorily discharged without providing another discharging part such as a developer discharging roller at the openings35aas a developer discharging port, so that agglomeration and bridge of the developer in the neighborhood of the openings35acan be prevented. As a result, even in the case where the developer in the developer accommodating member16is agglomerated by tapping during transportation, storage or the like, the agglomerated developer is broken by the movement of the entire developer accommodating member16and the periphery of the openings35aas described above, so that it is possible to prevent a state in which it is difficult to discharge the developer.

Further, even when the rotatable member20is disposed in the immediate neighborhood of the developer accommodating member16, the stiffness of the opening-containing side X is increased, and therefore not all the loads due to the flexure of the opening-containing side X by the weight of the developer filled in the developer accommodating member16are exerted on the rotatable member20. As a result, the rotatable member20and the developer accommodating member16can be disposed close to each other, and therefore the developer accommodating unit25can be lowered with respect to the vertical direction and thus the process cartridge can be downsized.

(Example of Single Part for Urging Member)

The urging sheet21is not constituted by separate parts consisting of the rotatable member20and the urging sheet21but may also be constituted by a single part, as shown in (a) ofFIG. 26, prepared by providing the urging sheet21integrally with a projection21cfunctioning as the urging sheet21. Also in this case, similarly, the developer can be discharged. In the case where the urging sheet21is constituted by only the rotatable member20, when the urging sheet21is viewed in its cross section perpendicular to its rotation center, the cross section of the rotatable member20may have a polygonal shape ((b) ofFIG. 26) or a cam shape ((c) ofFIG. 26). Also, in this case, the developer accommodating member16can be pressed against a frame29to be deformed.

This is because when the urging sheet21is disposed so as to contact at least the developer accommodating member16, a distance from the rotation center of the urging sheet21to the outer end of the urging member is changed and therefore the penetration depth of the urging sheet21with respect to the developer accommodating member16is also changed. That is, so long as the shaft portion (urging member) is not a shaft portion having a circular cross section including the rotation shaft as its center, the developer accommodating member16can be deformed by the rotation of the urging sheet21. As shown inFIG. 20, a dimension of the projection21cfrom the center of the urging sheet21to a remote outer end of the urging sheet21and a dimension21dclose to an outer end of the shaft portion are different from each other and therefore the penetration depth of the urging sheet21with respect to the developer accommodating member16is also changed.

Part (b) ofFIG. 5is a sectional view of an urging sheet21having a cross-shape in cross section, and (a) ofFIG. 5is a cross-sectional illustration of the developer accommodating unit25including the cross-shaped urging sheet21. As shown inFIG. 5, in the case where four projections21eeach having the same distance from the center of the urging member21to an associated outer end are provided, outer configurations (21c) of the four projections21eare the same. However, the urging member21includes a portion, other than the projections21e, having an outer end (dimension21d) close to the center and therefore the penetration depth with respect to the developer accommodating member16can be changed. That is, the urging sheet21can be constituted as a rotatable member including portions different in distance from its rotation center to its outer end in the cross section perpendicular to the rotation center of the urging sheet21.

Thus, the developer accommodating member16is urged by the urging sheet21(in the arrow J direction) to be pressed against the frame29, thus being deformed to decrease its inside volume, so that the inside developer is pushed out to be discharged from the openings35a(arrow I direction).

In an attitude during the image formation, the rotatable member20of the urging sheet21is positioned under the developer accommodating member16in contact with the developer accommodating member16with respect to the direction of gravitation. The cross-sectional shape of the rotatable member20of the urging sheet21is rectangular not is not circular and therefore by the rotation of the rotatable member20, the penetration depth of the rotatable member20with respect to the developer accommodating member16is periodically changed as described above. Also by the change in penetration depth of the rotatable member20with respect to the developer accommodating member16, the developer accommodating member16can be changed in volume and can be vibrated, so that the developer discharging property can be improved.

Parts (a) to (c) ofFIG. 19are sectional views for illustrating a structure of a developer accommodating unit25in this embodiment. Constituent elements (members), of the developer accommodating unit25in this embodiment, having the same constitutions and effects as those of the developer accommodating unit25in Embodiment 1 are represented by the same reference numerals or symbols and will be appropriately omitted from description. Also in this embodiment, the developer accommodating unit25can be applied to the image forming apparatus similar to that in Embodiment 1, and therefore the explanation of the image forming apparatus will be omitted. The developer accommodating unit25in this embodiment is characterized in that the side on which the self-weight of the developer is exerted is not limited to the lower side with respect to the vertical direction. That is, in Embodiment 1, the self-weight of the developer is exerted toward the lower side with respect to the vertical direction, but in this embodiment, as shown in (b) ofFIG. 19, the developer accommodating member16is flexed in an arrow K.

Part (a) ofFIG. 19shows a state in which the developer G is not present in the developer accommodating member16. In (b) ofFIG. 19, a positional relationship between the developer accommodating member16and the rotatable member20is such that the self-weight of the developer G is exerted in the arrow K direction when the developer G is filled, and thus the developer accommodating member16is flexed toward the rotatable member20, so that the rotatable member20provided in the neighborhood of the developer accommodating member16enters (urges) the developer accommodating member16. In this case, with respect to the rotatable member20, an excessive torque is generated. Therefore, as shown in (c) ofFIG. 19, in a side where the urging sheet21of the rotatable member20contacts the developer accommodating member16, a bent-shaped portion U (continuously connected uneven shape) is provided so as not to establish a positional relationship as shown in (b) ofFIG. 19. That is, by providing the bent-shaped portion U, the positional relationship between the developer accommodating member16and the rotatable member20is set at a state in which the bent-shaped portion U and the rotatable member20are spaced.

As described above, by providing the plurality of sides defined by the bent portion not only at the lower portion with respect to the vertical direction but also in the side where the developer G receives the gravitation, the degree of flexure of the developer accommodating member16can be reduced.

According to the constitution of Embodiments 1 and 2 described above, the stiffness of the developer accommodating member16at a portion which receives the powder pressure of the developer G is increased, so that the degree of flexure of the developer accommodating member16by the self-weight of the developer G can be reduced. As a result, downsizing of the developing device and improvement inefficiency of discharging the developer G from the developer accommodating member16can be compatibly realized. Incidentally, the number of the plurality of sides as the opening-containing side X described above is principally two, but is not limited to this constitution, i.e., may also be a plurality of numbers of three or more.

According to the present invention, the stiffness of the flexible container at the portion which receives the power pressure of the developer is increased, so that the degree of flexure of the flexible container by the self-weight of the developer can be reduced. As a result, it is possible to compatibly realize the downsizing of the developing device and the improvement in developer discharging efficiency from the flexible container.

This application claims priority from Japanese Patent Application No. 123634/2012 filed May 30, 2012, which is hereby incorporated by reference.