Developer supplying container, developing device having same and process cartridge

Abstract: A guide surface for engaging by a flexible film member (5) closing a developer discharge opening (4) of a developer supplying container is disposed at a downstream side of an elastic seal member (6) against which the film (5) is slidingly contacted when the film (5) is pulled out, whereby the film (5) is bent convexly against the elastic seal member (6).

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a developer supplying container for supplying developer used for developing an electrostatic latent image, a developing device having such a developer supplying container, and a process cartridge having a developing device comprising such developer supplying container and removably mountable within an image forming apparatus. Related Background Art It is well known to provide a technique wherein, in a developer supplying container having an opening initially closed by a flexible film, the opening is opened by pulling out the flexible film and developer is supplied, through the opening, from the developer supplying container to a developing device having a developer carrying or bearing member. In such a technique, at an outlet portion through which the film is pulled out, a compressible elastic seal member is disposed to engage by the film, thereby sealing the clearance between the film and the outlet portion to prevent the developer from leaking out of the container or to remove the developer adhered to the film from it. However, in pulling out the film, if the film is pulled in a direction that the excessive pressure acts on the elastic seal member, it will be difficult to pull the film due to the greater load on the film or the film may be torn to cause the leakage of the developer through the outlet portion. FR-A-2.304.106 describes a container of electrophotographic powder and a device to receive the container in a copying apparatus, in which a toner container is provided with an opening through which the toner can flow and a removable film normally closing this opening. The container includes a removable cleaning cover which cooperates with an edge on the container to remove by attrition any toner particle on the film, when this latter is peeled from the container. A charging device maintains the container and the cleaning cover in relative positions so that upon peeling the film out of the container, the film portions in contact with the toner are cleaned by sliding on a spongy sheet laying on the cover. The publication "Built-in Cartridge Toner Trap", Research Disclosure (310), February 1990, 99 describes a device for cleaning toner from the peelable lid and trapping it in a formed recess. A soft durometer sponge is attached to the cartridge in a specific orientation so that as the lid is removed it rubs on the sponge scraping off the excess toner. US - A - 4,873,549 describes a process unit of an image forming apparatus in which the developer is contained in a space of a developing device defined by a seal member which can be opened or peeled off for use at the time of setting the process unit. The above prior art documents fail to provide a control on the pulling stress applied to the film, in order not to excessively stress the sponge and avoid damages thereto which would cause leaking of toner SUMMARY OF THE INVENTION An object of the present invention is to reduce a load acting on an elastic seal member disposed at an outlet portion through which a flexible film member initially closing a developer discharge opening of a developer supplying container is pulled out, when the flexible film member is pulled out through the outlet portion. Another object of the present invention is to prevent the flexible film member from tearing when the film member is being pulled out. A further object of the present invention is to prevent the increase in a pulling load acting on the flexible film member when it is being pulled out. The present invention provides a developer supplying container for supplying developer to a developing device for developing an electrostatic latent image, comprising: a container body containing the developer and having an opening through which the developer is supplied to said developing device; a flexible film member initially closing said opening and having a first surface, a second surface opposed to said first surface, and one free end portion, said flexible film member being adapted to be pulled out from an outlet portion to open said opening by pulling said free end portion; an elastic seal member provided at said outlet portion and with which said first surface of said flexible film member being pulled out from said outlet portion is slidingly contacted; a moving path of said flexible film member comprising a first path portion disposed at an upstream side of said elastic seal member, a second path portion contiguous to said first path portion and along which said first surface of said flexible film member is contacted with said elastic seal member, and a third path portion contiguous to said second path portion and disposed at a downstream side of said elastic seal member; characterized by a protruded guide portion formed contiguous to the elastic seal member having a film guide surface with which said first surface of said flexible film member is contacted in said third path portion, said film guide surface being contacted with said flexible film member at a position offset from an extension line of said first path portion toward a direction directing from said first surface of said flexible film member (5) to said second surface, thereby regulating a moving direction of said flexible film member in said second path portion. The present invention also provides a developing device for developing an electrostatic latent image, comprising: a movable developer carrying member for carrying developer and for conveying the developer to a developing station where the developer is applied to the electrostatic latent image; a first container within which said movable developer carrying member is disposed; a second container containing the developer; an opening for shifting the developer from said second container to said first container; a flexible film member initially closing said opening and having a first surface, a second surface opposed to said first surface, and one free end portion, said flexible film member being adapted to be pulled out from an outlet portion to open said opening by pulling said free end portion; an elastic seal member provided at said outlet portion and with which said first surface of said flexible film member being pulled out from said outlet portion is slidingly contacted; a moving path of said flexible film member comprising a first path portion disposed at an upstream side of said elastic seal member, a second path portion contiguous to said first path portion and along which said first surface of said flexible film member is contacted with said elastic seal member, and a third path portion contiguous to said second path portion and disposed at a downstream side of said elastic seal member; characterized by a protruded guide portion formed contiguous to the elastic seal member having a film guide surface with which said first surface of said flexible film member is contacted in said third path portion, said film guide surface being contacted with said flexible film member at a position offset from an extension line of said first path portion toward a direction directing from said first surface of said flexible film member to said second surface, thereby regulating a moving direction of said flexible film member in said second path portion. Moreover, the present invention also provides a process cartridge removably mountable within an image forming apparatus, comprising: an image bearing member; a developing device for developing an electrostatic latent image formed on said image bearing member; and a frame removably engageable by a supporting portion of said image forming apparatus and within which said image bearing member and said developing device are disposed. With this arrangement, since the increase in a compressed amount of the elastic seal member can be prevented, it is possible to reduce the load acting on the elastic seal member, to prevent the elastic seal member from damaging and to prevent a pulling force for the flexible film member from increasing. The other objects and features of the present invention will be apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of a main portion of a developer supplying container according to a preferred embodiment of the present invention; Fig. 2 is a perspective view, partially in section, of the developer supplying container; Fig. 3 is a sectional view of a developing device on which the developer supplying container of Fig. 2 is mounted; Fig. 4 is an elevational sectional view of an image forming apparatus within which the developing device can removably be mounted; Fig. 5 is a sectional view of the developing device of Fig. 4; and Fig. 6 is an elevational sectional view of an image forming apparatus within which a process cartridge can removably be mounted. DESCRIPTION OF THE PREFERRED EMBODIMENTS First of all, a developer supplying container, a developing device and a process cartridge according to a preferred embodiment of the present invention will be explained. In Fig. 2, a developer supplying container 1 which can removably be mounted on a developing device shown in Fig. 3 comprises a container body 2 defining a containing chamber 3 for containing and storing developer, and a flange portion 13 integrally formed with the container body 2 and having a developer discharge opening 4. The discharge opening 4 is initially closed by a flexible film 5 made of synthetic resin such as polyethylene or the like. That is to say, the film 5 is pealably adhered to an outer surface of the flange portion 13 around the discharge opening 4 by heat-seal or the like. The film 5 has a first portion adhered to the flange portion 13, and a second portion folded on the first portion at an angle of about 180°. The film 5 can be peeled from the flange portion 13 to open the discharge opening 4 when an operator pulls a free end portion 5a of the folded portion (second portion) of the film in a direction shown by the arrow A. A holder portion 7 is integrally formed with the flange portion 13, and a compressible and restorable elastic seal member (sponge elastomer such as rubber or felt) 6 is suppported by the holder portion 7 (see Figs. 1 and 3). The elastic seal member 6 is elastically abutted against the film 5 at an outlet portion for the film 5. When the film 5 is being pulled out, a surface (first surface) of the first portion of the film 5 with which the developer in the container body 2 was contacted is slid on the elastic seal member 6, so that the developer adhered to the first surface of the film 5 is removed or scraped by the elastic seal member 6. Accordingly, since no developer is adhered to the firm surface pulled out from the container 1, it is possible to prevent the operator's hand or wear from being smudged.by the developer. The developer supplying container of Fig. 2 can be mounted on a developing device 8 of Fig. 3. In Fig. 3, the developing device 8 comprises a developer containing portion 9 for receiving the developer 12 dropped from the container 1 through the discharge opening 4, and a developing roller 10 for carrying the developer supplied from the developer containing portion 9 and for supplying the developer, at a developing station D, to an electrostatic latent image formed on an image bearing member 11 such as an electrophotographic photosensitive member. Further, the developer containing portion 9 has guide portion 14 with which the flange portion 13 of the developer supplying container 1 can be slidingly engaged. The container 1 can be mounted on or dismounted from the developing device along the guide portions 14 by the operator. In a condition that the container 1 is mounted on the developing device 8, the container is held by the guide portions 14. The developer containing portion 9 has a slit opening 15 through which the film 5 is pulled out. The above-mentioned elastic seal member 6 is disposed at the slit opening (film outlet portion) 15, so that, after film 5 has been pulled in the direction A and was completely removed from the container 1, the slit opening 15 is sealed or closed by the elastic seal member 6, thereby preventing the developer in the developer containing portion 9 from leaking through the slit opening and preventing any foreign matter from entering into the containing portion 9 through the slit opening 15. Incidentally, in the illustrated embodiment, while the elastic seal member 6 was provided integrally with the developer supplying container 1, the elastic seal member 6 may be adhered to the developer containing portion 9, for example, at the slit opening 15 to separate the seal member from the container 1. Fig. 4 shows an example of an electrophotographic image forming apparatus 21 with which the developing device according to the present invention can be used. In the illustrated image forming apparatus 21, a photosensitive drum 11 comprising a conductive drum core and a photo-conductive layer (OPC member) disposed around the drum core is supported for rotational movement in a direction shown by the arrow. In the rotational direction of the drum 11, around the drum 11, there are arranged, in order, a corona discharger 23, a short focus optical element array 24, a developing device 8', a transfer corona discharger 26, and a cleaning device 27. In this image forming apparatus 21, the developing device 8' is supported and guided by guide rails 19, 20 formed on a frame of the image forming apparatus so that the developing device can be mounted within or dismounted from the apparatus by the operator. Within the apparatus, the developing device 8' is held by the guide rails 19, 20 at a developing station where a latent image formed on the photosensitive drum 11 is developed. In the above image forming apparatus 21, a surface of the photosensitive drum 11 is uniformly charged with a predetermined electric pole by the corona discharger 23, and then an original rested on an original support 22 reciprocally moving on the frame of the apparatus is illuminated by a lamp 25 so that light reflected from the original is focused on the drum 11 through the image focusing optical element array 24, thereby forming the latent image on the drum 11. The latent image so formed is developed by the developing device 8' with toner to form a toner image. The toner image is then transferred onto a transfer sheet by the transfer corona discharger 26. The transfer sheet is manually loaded on a transfer sheet supply tray 32 by the operator, and then is sent to a transfer station via convey rollers 33 and timing rollers 34. The transfer sheet to which the toner image was transferred is separated from the drum 11 by a separation means 35, and then is guided along a moving path 36 to reach a fixing device 37, where the toner image is permanently fixed to the transfer sheet. Then, the transfer sheet is discharged onto a sheet discharge tray 39 by discharge rollers 38. As shown in Fig. 5 which is a longitudinal sectional view of the developing device 8', in this developing device 8', a lower flange portion 13 of a container body 2 of a developer supplying container is secured, by screws or adhesive, to a developer containing portion 9 of the developing device within which a developing roller 10 is disposed, so that the container body 2 and the containing portion 9 are integrally formed with each other. As in the aforementioned embodiment, a developer discharge opening 4 of the container body 2 is closed by a flexible film 5. In this embodiment, the film 5 is pulled out in a longitudinal direction of the developing device as shown by the arrow A. An elastic seal member 6 similar to the aforementioned elastic seal member is disposed at a slit opening (film outlet portion) 15 and secured to the containing portion 9 to be engaged by a first surface of the film 5, so that, when the film 5 is being pulled out, the developer adhered to the first surface of a first portion of the film 5 is removed, and, after the film was completely pulled out, the slit opening 15 is closed by the seal member. The film 5 is removed from the developing device before the developing device 8' is mounted within an image forming apparatus 21 or after the developing device was mounted within the image forming apparatus or during the developing device is being inserted in the image forming apparatus. When the developer in the developing device 8' is used up, the developing device is removed from the image forming apparatus 21, and a new developing device 8' is mounted within the apparatus. In Fig. 6, a process cartridge 41 having a frame 40 incorporating therein the developing device 8', photosensitive drum 11, charger 23 and cleaning device 27 as shown in Figs. 4 and 5 is removably mounted within an image forming apparatus 21'. That is to say, when the developer 12 in the developing device 8' of the process cartridge is used up or consumed, the process cartridge is dismounted from the apparatus 21' and a new process cartridge 41 is mounted within the apparatus. The process cartridge 41 is mounted within or dismounted from the image forming apparatus along guides 19, 20 by the operator, and is held at an image forming station in the apparatus by the guides 19, 20. The film 5 is removed from the developing device 8' to supply the developer 12 from the container body 2 to the containing portion 9, before the process cartridge 41 is mounted within the image forming apparatus 21' or after the process cartridge was mounted within the image forming apparatus or during the process cartridge is being inserted into the image forming apparatus. While the process cartridge 41 shown in Fig. 6 has the charger 23 and the cleaning device 27, one or both of them may be omitted from the process cartridge 41. The film outlet portion and therearound of the developing device according to each of the aforementioned embodiments is shown in Fig. 1 in detail. In Fig. 1, a moving path for pulling the flexible film 5 comprises first, second and third path portions P 1 , P 2 and P 3 . The first path portion P 1 is a path through which the film 5 reaches the elastic seal member 6, the second path portion P 2 is a path along which the first surface 51 of the film is slidingly contacted with the elastic seal member 6, and the third path portion P 3 is a path along which the film 5 is separated from the elastic seal member 6. That is to say, the first path portion P 1 is disposed at an upstream side of the elastic seal member 6 in a film pulling direction, and the third path portion P 3 is disposed at a downstream side of the elastic seal member 6 in the film pulling direction, and the first, second and third path portions P 1 , P 2 and P 3 are contiguous to each other in order. In Fig. 1, a film guide surface 43 is arranged at a downstream side of the elastic seal member 6 in the film pulling direction, i.e., in the third path portion P 3 . The guide surface 43 is offset from an extension line 45 extending from the first path portion P 1 (along which the film 5 reaches the elastic seal member 6) toward a direction directing the first surface 51 of the film 5 which can be slidingly contacted with the elastic seal member 6 to a second surface 52 of the film opposed to the first surface 51. In Fig. 1, since the second surface 52 is positioned above the first surface 51, the guide surface 43 is also positioned above the extension line 45. The guide surface 43 contacts with the first surface 51 of the film 5 so that the moving direction of the film 5 in the second path portion P 2 , i.e., the moving direction of the film 5 passing through the elastic seal member 6 is regulated by the guide surface (Incidentally, as mentioned above, when the discharge opening 4 of the container body 2 is closed by the film 5, the first surface 51 of the first portion of the film 5 is contacted with the developer in the container body 2). In the developing device shown in Fig. 5, the guide surface 43 is formed on a protruded portion 44 of the developer containing portion 9, as shown in Fig. 1, and, in the developer supplying container 1 shown in Fig. 2, the guide surface is formed on a protruded portion 44 integrally formed with the holder portion 7. In place of the guide surface formed on the protruded portion 44 of the holder portion 7 as shown in Fig. 2, a protruded portion having the guide surface 43 may be formed on the developer containing portion 9 of the developing device as shown in Fig. 3. The guide surface (film sliding surface) 43 is formed from a hard member made of hard plastic, metal or the like. In any way, the guide surface 43 is preferably formed as an arcuated surface for reducing the sliding resistance of the film 5 and for preventing the tearing of the film 5. The flexible film 5 is bent upwardly away from the extension line 45 in the second path portion P 2 (at a corner 42 of the flange 13 of the container body 2 in Fig. 1) because of the presence of the protruded guide surface 43. In other words, in the second path portion P 2 where the film 5 is slidingly contacted with the elastic seal member 6, the film 5 is bent convexly toward the elastic seal member 6. At the corner 42 of the flange, a bending angle a of the film 5 (i.e., an angle between a line 46 perpendicular to the extension line 45 and a moving path of the film 5 after bending) is greater than 0 degree, but smaller than 90 degrees (if the angle a is greater than 90 degrees, it means that the guide surface 43 does not exist above the extension line 45; and, in this case, the inconvenience as mentioned above will occur). In any way, even when the operator pulls the film 5 in any direction such as direction A, B or C, since the moving direction of the film 5 on the elastic seal member 6 is regulated by the guide surface 43, it is possible to prevent the excessive load from acting on the elastic seal member 6, thereby preventing the damage of the seal member. After film peeling tests regarding developer supplying containers or developing devices having the above-mentioned angle a of 30 - 45 degrees were effected, it was found that the peeling resistance was about 3 - 6 Kg and the elastic seal member was not damaged or torn at all. In the peeling tests, even when the films were pulled in the direction B or the direction C, any problem did not occur. Further, after the peeling of the film, it was found that all of the developer in the container body 2 was substantially dropped into the developer containing portion 9 and no developer was leaked from the container and the containing portion. Further, vibration test, decompression test, dropping test and high temperature/humidity endurance test were effected as the environmental test and transportation test, regarding ten developer supplying container (for each test). As a result, it was found that there was no abnormity such as the leakage of developer in all of the tests. Further, even when the peeling test, environmental test and transportation test were effected regarding developer supplying containers having the above-mentioned angle a of 60 - 80 degrees, it was found that no abnormity was ascertained. To the contrary, in a developer supplying container having no guide surface 43, there is no problem when the film 5 is pulled out in the direction A or C; however, if the film is pulled in the direction B, the elastic seal member 6 will be entrained with the film, resulting in the tearing of the elastic seal member. In fact, after the peeling test was effected regarding 100 developer supplying containers (having no guide surface) by pulling the film in the direction B, it was found that the elastic seal member 6 was torn in five containers. In this case, the peeling resistance or strength was greater such as 8 - 10 Kgf, and it was found that, after the film was completely removed, the developer was leaked through the torn elastic seal member 6. Incidentally, after the film is completely removed from the container, since the elastic seal member 6 is closely contacted with the flange 13 of the container body 2 by its own elastic restoration to seal the slit opening 15 thereby preventing the scattering of the developer, the tearing of the elastic seal member will make the sealing of the slit opening incomplete. Further, in the illustrated embodiments, while an example that the film is peeled from the container to which the film is adhered was explained, a portion of the film may be torn longitudinally from the remaining portion of the film, as disclosed in the Japanese Patent Application Laid-open Nos. 59-13262 and 1-315779.

Claims: A developer supplying container (1) for supplying developer to a developing device for developing an electrostatic latent image, comprising: a container body (2) containing the developer and having an opening (4) through which the developer (12) is supplied to said developing device; a flexible film member (5) initially closing said opening (4) and having a first surface (51), a second surface (52) opposed to said first surface (51), and one free end portion (5a), said flexible film member (5) being adapted to be pulled out from an outlet portion (15) to open said opening (4) by pulling said free end portion (5a); an elastic seal member (6) provided at said outlet portion (15) and with which said first surface (51) of said flexible film member (5) being pulled out from said outlet portion (15) is slidingly contacted; a moving path (P1, P2, P3) of said flexible film member (5) comprising a first path portion (P1) disposed at an upstream side of said elastic seal member (6), a second path portion (P2) contiguous to said first path portion (P1) and along which said first surface (51) of said flexible film member (5) is contacted with said elastic seal member (6), and a third path portion (P3) contiguous to said second path portion (P2) and disposed at a downstream side of said elastic seal member (6); characterized by : a protruded guide portion (43,44) formed contiguous to the elastic seal member (6) having a film guide surface (43) with which said first surface (51) of said flexible film member (5) is contacted in said third path portion (P3), said film guide surface (43) being contacted with said flexible film member (5) at a position offset from an extension line of said first path portion (P1) toward a direction directing from said first surface (51) of said flexible film member (5) to said second surface (52), thereby regulating a moving direction of said flexible film member (5) in said second path portion (P2). A developer supplying container (1) according to claim 1, wherein said flexible film member (5) has a first film portion attached to said container body (2) around said opening (4), and a second film portion folded on said first film portion and having said free end portion (5a), whereby, when said opening (4) is closed by said flexible film member (5), a first surface (51) of said first film portion (60) is contacted with the developer in said container body (2). A developer supplying container (1) according to claim 2, wherein said first film portion is peelably adhered to said container body (2) around said opening (4). A developer supplying container (1) according to any of claims 1 to 3, wherein said elastic seal member (6) is made from sponge elastic body or felt. A developing device (8) for developing an electrostatic latent image, comprising: a movable developer carrying member (10) for carrying developer and for conveying the developer to a developing station (D) where the developer is applied to the electrostatic latent image; a first container (9) within which said movable developer carrying member (10) is disposed; a second container (2) containing the developer; an opening (4) for shifting the developer from said second container (2) to said first container (9); a flexible film member (5) initially closing said opening (4) and having a first surface (51), a second surface (52) opposed to said first surface (51), and one free end portion (5a), said flexible film member (5) being adapted to be pulled out from an outlet portion (15) to open said opening (4) by pulling said free end portion (5a) ; an elastic seal member (6) provided at said outlet portion (15) and with which said first surface (51) of said flexible film member (5) being pulled out from said outlet portion (15) is slidingly contacted; a moving path (P1,P2,P3) of said flexible film member comprising a first path portion (P1) disposed at an upstream side of said elastic seal member (6), a second path portion (P2) contiguous to said first path portion (P1) and along which said first surface (51) of said flexible film member (5) is contacted with said elastic seal member (6), and a third path portion (P3) contiguous to said second path portion (P2) and disposed at a downstream side of said elastic seal member (6); characterized by : a protruded guide portion (43,44) formed contiguous to the elastic seal member (6) having a film guide surface (43) with which said first surface (51) of said flexible film member (5) is contacted in said third path portion (P3), said film guide surface (43) being contacted with said flexible film member (5) at a position offset from an extension line of said first path portion (P1) toward a direction directing from said first surface (51) of said flexible film member (5) to said second surface (52), thereby regulating a moving direction of said flexible film member (5) in said second path portion (P2). A developing device (8) according to claim 5, wherein said flexible film member (5) has a first film portion attached to said second container (2) around said opening (4), and a second film portion folded on said first film portion and having said free end portion (5a), whereby, when said opening (4) is closed by said flexible film member (5), a first surface (51) of said first film portion is contacted with the developer in said second container (2). A developing device (8) according to claim 6, wherein said first film portion is peelably adhered to said second container (2) around said opening (4). A developing device (8) according to any of claims 5 to 7, wherein said elastic seal member (6) is made from sponge elastic body or felt. A process cartridge (41) removably mountable within an image forming apparatus (21'), comprising: an image bearing member (11) ; a developing device (8') according to any of claims 5 to 8 for developing an electrostatic latent image formed on said image bearing member (11); and a frame (40) removably engageable by a supporting portion of said image forming apparatus (21') and within which said image bearing member (11) and said developing device (8') are disposed.

Inventors: NAGASHIMA TOSHIAKI, NAGASHIMA, TOSHIAKI, NAGASHIMA, TOSHIAKI, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1993
Main classification: G03G15
IPC codes: G03G15