Mechanism for opening/closing a toner falling aperture

Abstract: A mechanism for opening/closing a toner falling aperture is adapted to open/close a toner falling aperture (TC2) formed in the bottom of a toner cartridge main body (T1) in which toner is housed. Disposed inside of the toner cartridge main body (T1) is a screw conveyor (SC) for conveying the toner to the toner falling aperture. While the toner cartridge is not under use, an elastic sealing member (S) attached to the top surface of the bottom (TC1) of the toner cartridge main body (T1), closes the toner falling aperture (TC2). One end of the sealing member (S) is secured to the screw conveyor (SC). When the toner cartridge is set to a predetermined portion of the main body of an image forming apparatus and the screw conveyor (SC) is driven, the screw conveyor takes up the sealing member (S) while winding the same thereon, thus opening the toner falling aperture (TC2). The sealing member (S) to which toner is sticked, is taken up by the screw conveyor (SC) and held inside of the toner cartridge main body (T1).

Description: The present invention relates to a mechanism for opening/closing a toner falling aperture formed in the bottom of the main body of a toner cartridge in which toner is housed according to the preamble of claim 1. In such a manner, toner is supplied from a toner cartridge to the developing device in an image forming apparatus such as an electrostatic copying apparatus, a facsimile device, a laser beam printer or the like. In an image forming apparatus as mentioned above, a toner cartridge is removably attached to a housing in the main body of the image forming apparatus. A toner cartridge, the toner of which has been used up, is to be replaced with a new toner cartridge. A mechanism according to the preamble of claim 1 is known from EP-A-0514666. In the conventional mechanism, a slidable shutter is provided which closes the toner cartridge and is adapted to open the toner falling aperture by a sliding movement. The slidable shutter comprises a first shutter mounted on a shutter mounting body and a second shutter slidably mounted on the first shutter. An opening in the lower part of the toner cartridge main body is sealed by means of a flexible sealing member, and the first shutter and the second shutter cooperate with each other to pull the flexible sealing member sidewards to fully open the bottom of the toner cartridge main body so that the toner is discharged downwards from the opening when the sealing member has been stripped off. The object underlying the present invention is to provide a reliable mechanism for closing/opening a toner falling aperture which reliably prevents toner from scattering and can readily be opened when installed in an image forming apparatus. According to the invention, a mechanism for opening/closing a toner falling aperture formed in the bottom of the main body of a toner cartridge in which toner is housed comprises the features of claim 1. Further developments of the mechanism according to the invention are specified in the subclaims. According to the arrangement above-mentioned, when the toner cartridge main body alone is inserted into the image forming apparatus in which the devel-oping unit main body has been set in the interior of the housing and in which the lower toner falling aperture has been opened, the second engaging means are engaged with each other, causing the upper shutter member to open the upper toner falling aperture. When the toner cartridge main body alone is pulled out, the second engaging means are disengaged from each other so that the first biasing means causes the upper shutter member to automatically close the upper toner falling aperture. This prevents toner from scattering. When the toner cartridge main body and the developing unit main body are integrally inserted into the interior of the housing of the main body of the image forming apparatus, the engagement of the first engaging means causes the lower shutter member to open the lower toner falling aperture and the engagement of the second engaging means with each other causes the upper shutter member to open the upper toner falling aperture in association with the opening of the lower toner falling aperture. When the toner cartridge main body and the developing unit main body are integrally pulled out, the disengagement of the first engaging means causes the first and second biasing means to automatically close the upper and lower toner falling apertures. Provision is made such that the upper and lower shutter members are interlockingly operated. This not only provides simplification of the structure and reduction in production cost, but also prevents toner from scattering due to difference in opening/closing timing between the upper and lower shutter members. Preferably, the toner cartridge main body and the developing unit main body are relatively slidable with respect to each other by a pair of slide mechanisms including grooves and projecting members which are adapted to be engaged with each other, and the second engaging means are disposed between the bottom of the toner cartridge main body and the top surface of the developing unit main body and between the pair of slide mechanisms. If the second engaging means cross the grooves, it is difficult to seal the groove portions that the second engaging means cross. According to the present invention, however, the second engaging means do not cross the grooves and the like. It is therefore easy to seal the space between the bottom of the toner cartridge main body and the top surface of the developing unit main body. Preferably, the mechanism for opening/closing a toner falling aperture further comprises: a first stopper disposed at a predetermined part of the housing concave for stopping, at a predetermined insertion stroke position, the toner cartridge main body which is inserted; and a second stopper disposed at a predetermined part of the housing concave for stopping, at a predetermined insertion stroke position, the developing unit main body which is inserted: and the positions where the developing unit main body and the toner cartridge main body are stopped by the respective stoppers, are different from each other such that the lower shutter member opens the lower toner falling aperture before the upper shutter member opens the upper toner falling aperture and that the upper shutter member closes the upper toner falling aperture before the lower shutter member closes the lower toner falling aperture when the developing unit main body and the toner cartridge main body connected thereto are integrally inserted in and removed from the interior of the housing. According to the arrangement above-mentioned, the lower shutter member opens the lower toner falling aperture before the upper shutter member opens the upper toner falling aperture, and the upper shutter member closes the upper toner falling aperture before the lower shutter member closes the lower toner falling aperture. This securely prevents toner from scattering between the opposite surfaces of the toner cartridge main body and the developing unit main body. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A to 1C are schematic section views of a mechanism for opening/closing a toner falling aperture according to a first embodiment of the present invention, illustrating the successive steps at which the toner cartridge and the developing unit are integrally inserted; Figure 2 is a schematic view of the inside arrangement of a copying apparatus including the mechanism for opening/closing a toner falling aperture according to the present invention; Figure 3 is a schematic perspective view of the toner cartridge and the developing unit; Figure 4 is a perspective view of the main portion of the developing unit; Figure 5 is an exploded perspective view of the top surface of the developing unit and a lower shutter member; Figure 6 is a perspective view of the main portion of the toner cartridge; Figure 7 is a bottom view of the toner cartridge; Figure 8 is an exploded perspective view of both shutter members; Figure 9 is a section view of the main portions of the developing unit and the toner cartridge; Figures 10A to 10C are schematic section views illustrating in succession the operations in which the developing unit is inserted; and Figures 11A to 11C are schematic section views illustrating the successive operations of a mechanism for opening/closing a toner falling aperture according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will discuss in detail embodiments of the present invention with reference to the attached drawings. First Embodiment With reference to Fig. 1A to Fig. 10C, the following will discuss a first embodiment of the present invention. Referring to Fig. 2, a copying apparatus has, inside of the main body 1 thereof, (i) an optical system 3 where a document placed on a document placing plate 2 is illuminated and scanned, and light reflected from the document is guided to a photoreceptor drum 42, (ii) an image forming unit 4 where an electrostatic latent image formed on the photoreceptor drum 42 is converted into a toner image by a developing device 41, and the toner image is then transferred onto paper, and (iii) a paper delivery unit 5 where paper is pulled out from a paper feeding tray 61 in a paper housing portion 6 by a paper feeding roller 51 having a semicircular section, and the paper is passed through the image forming unit 4 and then discharged to a discharge tray 56 inside of the main body of the copying apparatus. Removably mounted on the main body 1 of the copying apparatus is a toner cartridge TC for supplying toner to the developing device 41. A mechanism for opening/closing a toner falling aperture according to an embodiment of the present invention is mounted to the toner cartridge TC. Referring to Fig. 2, the copying apparatus main body 1 has a lower unit 7 partitioned by a lower casing 71, and an upper unit 8 partitioned by an upper casing 81 supported in a manner rotatable around a predetermined axis of rotation m at the lower end thereof, the upper unit 8 being relatively rotatable with respect to the lower unit 7. The copying apparatus main body 1 is of a so-called clamshell type in which the upper unit 8 is rotatably opened/closed with respect to the lower unit 7. The optical system 3 is arranged such that a document is illuminated by a fluorescent lamp 39 having a reflector plate 38 secured to a first moving frame 3A, and light reflected from the document is guided to the photoreceptor drum 42 after successively passing through a first mirror 31 secured to the first moving frame 3A, second and third mirrors 32, 33 secured to a second moving frame 3B, a lens 37, fourth and fifth mirrors 34, 35 secured to a third moving frame 3C, and a sixth mirror 36. In the image forming unit 4, there are successively disposed, around the photoreceptor drum 42, a corona discharger 43, the developing device 41, a transferring corona discharger 44 and a cleaning device 45 in this order. The image forming unit 4 is arranged such that a document image is formed to form an electrostatic latent image on the outer peripheral surface of the photoreceptor drum 42 uniformly electrically charged by the corona discharger 43, the electrostatic latent image is converted into a toner image by the developing device 41, the toner image is transferred to paper by the transferring corona discharger 44, and residual toner is collected by the cleaning device 45. The paper delivery unit 5 comprises: the paper feeding roller 51 adapted to pull out paper, one by one, from the paper feeding tray 61; a delivery roller 52 for delivering paper from a manual paper feeding part 60 or the paper feeding tray 61; resist means 53 with which the tip of paper delivered by the delivery roller 52 comes in contact, causing the paper to temporarily wait, the resist means 53 being formed by driving roller means 53a and driven roller means 53b; a fixing unit 54 for fixing a toner image transferred onto paper; and a pair of discharging roller means 55. The toner cartridge TC comprises: a container-like toner cartridge main body T1; an aperture TC2 which is formed in the bottom TC1 of the toner cartridge main body T1 and through which toner is adapted to fall toward the developing device 41; a pair of screw conveyors disposed inside of the toner cartridge main body T1 in the longitudinal direction thereof. The screw conveyors are adapted to be rotated in opposite directions to feed toner in opposite direcitons. This causes toner to be circulated while passing on the aperture TC2 inside of the toner cartridge main body T1. Referring to Fig. 2, a developing device 41 is arranged in the form of an integral developing unit GU, and toner is to be supplied by a replaceable toner cartridge TC. With reference to Fig. 3, a copying apparatus is arranged such that the developing unit GU and the toner cartridge TC are integrally or individually inserted in and removed from a predetermined part of the copying apparatus main body 1 (the inserting direction is shown by K1, while the removing direction is shown by K2). As shown in Figs. 1A to 1C, an upper shutter member US and a lower shutter member SS are disposed for opening/closing a toner falling aperture TC2 of the toner cartridge TC and a toner falling aperture GU2 of the developing unit GU, respectively, and are adapted to be interlockingly operated. When inserted, the developing unit GU and the toner cartridge TC are stopped when the insertion-side ends thereof come in contact with a stopper L (See Fig. 1C) at a predetermined insertion stroke position. Referring to Figs. 1A to 1C, Fig. 4, Fig. 5 and Fig. 6, the developing unit main body G1 has guide grooves GU3 in which both lateral edges of the lower shutter member SS are inserted. This enables the lower shutter member SS to be slided on the top surface GU1 of the developing unit main body G1. Further, the developing unit main body G1 has guide grooves GU4 in which projections TC3 of the toner cartridge TC are inserted. This enables the toner cartridge TC to be slidably inserted in and removed from the developing unit GU. Referring to Fig. 5, the lower shutter member SS is made of a plate member and has a lower communicating aperture SS1 which is adapted to communicate with the aperture GU2 in the developing unit GU when the lower shutter member SS is slided to a predetermined position. The lower shutter member SS is provided on the top surface thereof with an upward projection SS2 engageable with a groove US2 in the upper shutter member US. The lower shutter member SS is provided at the underside thereof with a downward projection SS3, serving as first engaging means, which passes through a slit GU5 in the top surface GU1 of the developing unit GU and which is engageable with a projection J1 of the copying apparatus main body 1. By a compression coiled spring FS serving as biasing means, the lower shutter member SS is normally biased toward the inserting direction K1 such that the aperture SS1 is positionally shifted toward the inserting direction K1 with respect to the aperture GU2 in the developing unit GU. That is, the lower shutter member SS is biased to close the aperture GU2. When the downward projection SS3 of the lower shutter member SS is engaged with the projection J1 of the copying apparatus main body 1, the lower shutter member SS opens/closes the aperture GU2 in association with the insertion and removal of the developing unit GU. The groove US2 in the upper shutter member US and the upward projection SS2 of the lower shutter member SS form second engaging means for interlockingly operating the upper and lower shutter members US, SS. Referring to Figs. 6 to 9, the toner cartridge main body T1 is a box-like container. Slidably attached to the toner cartridge main body T1 is the upper shutter member US for opening/closing the toner falling aperture TC2 formed in the bottom TC1 of the toner cartridge main body T1. The upper shutter member US has an upper communicating aperture US1 which is adapted to communicate with the aperture TC2 in the toner cartridge TC when the upper shutter member US is slided to a predetermined position. Also, the upper shutter member US has the groove US2 engageble with the upward projection SS2 of the lower shutter member SS when the upper shutter member US is slided to a predetermined position. By a compression coiled spring FU serving as biasing means, the upper shutter member US is normally biased toward the inserting direction K1 such that the aperture US1 is positionally shifted toward the inserting direction K1 with respect to the aperture TC2 in- the toner cartridge TC. That is, the upper shutter member US is biased to close the aperture TC2. The following will discuss the operation of the mechanism for opening/closing a toner falling aperture. First, with reference to Figs. 10A to 10C, the description will be made of the case where only the developing unit GU is mounted. With the lower shutter member SS so biased as to close the aperture GU2, the developing unit GU is inserted into a predetermined part of the copying apparatus main body 1 (Fig. 10A). When the developing unit GU reaches the terminal end of an insertion stroke, the downward projection SS3 of the lower shutter member SS is engaged with the projection J1 of the copying apparatus main body 1 (Fig. 10B). This restrains the lower shutter member SS from being relatively moved with respect to the copying apparatus main body 1. When the developing unit GU is further inserted, the compression coiled spring FS is contracted and the developing unit GU is relatively moved with respect to the lower shutter member SS, so that the aperture GU2 in the developing unit GU is opened. At the same time, the developing unit GU is stopped as coming in contact with the stopper L (Fig. 10C). When removing the developing unit GU, the operations above-mentioned may be reversed. That is, the developing unit GU may be removed with the aperture GU2 closed by the lower shutter member SS. With reference to Figs. 1A to 1C, the following description will discuss the case where the developing unit GU and the toner cartridge TC connected thereto are integrally inserted. With the developing unit GU connected to the toner cartridge TC, the groove US2 in the upper shutter member US is engaged with the upward projection SS2 of the lower shutter member SS, and the apertures US1, SS1 in the both upper and lower shutter members US, SS communicate with each other. When the developing unit GU and the toner cartridge TC are inserted (Fig. 1A) and reach the terminal end of the insertion stroke, the downward projection SS3 of the lower shutter member SS is engaed with the projection J1 of the copying apparatus main body 1 (Fig. 1B). This restrains the upper and lower shutter members US, SS from being relatively moved with respect to the copying apparatus main body 1. When the developing unit GU and the toner cartridge TC are further inserted, the compression coiled springs FU, FS are contracted,- and the developing unit GU and the toner cartridge TC are relatively moved with respect to the shutter members US, SS. Accordingly, the apertures GU2, TC2 in the developing unit GU and the toner cartridge TC are opened. At the same time, the developing unit GU and the toner cartridge TC are stopped as coming in contact with the stopper L (Fig. 1C). When removing the developing unit GU and the toner cartridge TC, the operations above-mentioned may be reversed. That is, the developing unit GU and the toner cartridge TC may be removed with the apertures TC2, GU2 closed by the shutter members US, SS. In this embodiment, the upper and lower shutter members US, SS for the toner cartridge TC and the developing unit GU are so biased as to close the apertures TC2, GU2. Accordingly, even though the toner cartridge TC alone or the developing unit GU alone is removed, no toner falls through the aperture TC2 or GU2. Provision is made such that the shutter members US, SS for the toner cartridge TC and the developing unit GU are interlockingly operated. This not only simplifies the structure to lower the production cost, but also prevents toner from scattering due to an undesired difference in opening/closing timing between the shutter members US, SS. The upward projection SS2 and the groove US2 serving as engaging means for interlockingly operating the shutter members US, SS, are disposed between the bottom TC1 of the toner cartridge main body T1 and the top surface GU1 of the developing unit main body G1 and between the pair of guide grooves GU4. It is now supposed that the upward projection SS2 crosses the guide grooves GU4. In such a case, it is required to provide a space in which the upward projection SS2 is relatively moved with respect to the guide grooves GU4. It is difficult to seal such a space. According to the first embodiment, however, it is easy to seal the space between the bottom TC1 of the toner cartridge main body T1 and the top surface GU1 of the developing unit main body G1. Second Embodiment Figs. 11A to 11C show a second embodiment of the present invention. The second embodiment differs from the first embodiment in Figs. 1A to 1C in the following two points. (i) Provision is made such that the toner cartridge TC and the developing unit GU are integrally inserted and removed as connected to each other by a predetermined holding force (See Fig. 11A). (ii) The stopper L has a stepped structure such that the developing unit GU and the toner cartridge TC are adapted to be stopped at different insertion stroke stop positions. Accordingly, the lower shutter member SS opens the aperture GU2 (See Fig. 11B) before the upper shutter member US opens the aperture TC2 (See Fig. 11C). When removing the toner cartridge TC and the developing unit GU, the upper shutter member US closes the aperture TC2 before the lower shutter member SS closes the aperture GU2. This second embodiment not only produces effects similar to those produced by the embodiment shown in Fig. 1A, but also securely prevents toner from scattering in the space between the opposite surfaces of the toner cartridge and the developing unit.

Claims: A mechanism for opening/closing a toner falling aperture (TC2) formed in the bottom (TC1) of the main body (T1) of a toner cartridge (TC) in which toner is housed, wherein a slidable shutter is provided which closes the toner cartridge (TC) and is adapted to open the toner falling aperture by a sliding movement, the mechanism being suitable for an image forming apparatus comprising a developing unit main body (G1) removably set into the interior of the main body (1) of the image forming apparatus, and having the toner cartridge (TC) mounted on top of the developing unit, characterized in that the toner cartridge main body (T1) is slidably connected to the top surface (GU1) of the developing unit main body (G1), in that the toner falling aperture comprises upper and lower toner falling apertures (TC2, GU2) respectively formed in the bottom of the toner cartridge main body (T1) and in the top surface (GU1) of the developing unit main body (G1), the apertures (TC2, GU2) being adapted to communicate with each other, and in that the mechanism further comprises: an upper shutter member (US) slidably disposed under the bottom of the toner cartridge main body (T1) for opening/closing the upper toner falling aperture (TC2); first biasing means (FU) for normally biasing the upper shutter member (US) to close the upper toner falling aperture (TC2); a lower shutter member (SS) slidably disposed on the top surface (GU1) of the developing unit main body (G1) for opening/closing the lower toner falling aperture (GU2); second biasing means (FS) for normally biasing the lower shutter member (SS) to close the lower toner falling aperture (GU2); first engaging means (SS3) disposed on the lower shutter member (SS) and adapted to be engaged with an engaging portion (J1) of the main body (1) of the image forming apparatus such that the lower shutter member (SS) opens the lower toner falling aperture (GU2) when the developing unit main body (G1) is removably attached to the interior of the main body (1) of the image forming apparatus; and second engaging means (SS2, US2) respectively disposed on the upper shutter member (US) and the lower shutter member (SS) for engaging the upper and lower shutter members with each other. The mechanism according to claim 1, wherein the upper shutter member (US) and the lower shutter member (SS) respectively have upper and lower communicating apertures (US1, SS1) adapted to communicate with each other when the upper and lower shutter members (US, SS) are engaged with each other by the second engaging means (SS2, US2); the upper communicating aperture (US1) is adapted to communicate with the upper toner falling aperture (TC2) when the upper shutter member (US) slides with respect to the toner cartridge main body (T1); and the lower communicating aperture (SS1) is adapted to communicate with the lower toner falling aperture (GU2) when the lower shutter member (SS) slides with respect to the developing unit main body (G1). The mechanism according to claim 1 or 2, wherein the first engaging means (SS3) comprise a projection formed on the underside of the lower shutter member (SS). The mechanism according to claim 1, 2 or 3, wherein the toner cartridge main body (T1) and the developing unit main body (G1) are relatively slidable with respect to each other by a pair of slide mechanisms (GU3, GU4) including grooves and projecting members which are engaged with each other; and the second engaging means (SS2, US2) are disposed between the bottom of the toner cartridge main body (T1) and the top surface (GU1) of the developing unit main body (G1) and between the pair of slide mechanisms (GU3, GU4). The mechanism according to any of claims 1 to 4, wherein one of the second engaging means (SS2, US2) comprises a projection (SS2), and the other of the second engaging means comprises a groove (US2) into and from which the projection is adapted to be inserted and come out. The mechanism according to any of claims 1 to 5, wherein the first biasing means (FU) comprises a compression coiled spring for normally biasing the upper shutter member (US) in the direction in which the toner cartridge main body (T1) is inserted. The mechanism according to any of claims 1 to 6, wherein the second biasing means (FS) comprise a compression coiled spring for normally biasing the lower shutter member (SS) in the direction in which the developing unit main body (G1) is inserted. The mechanism according to any of claims 1 to 7, further comprising: a first stopper (L) disposed at a predetermined part of the interior of the housing of the main body of the image forming apparatus for stopping, at a predetermined insertion stroke position, the toner cartridge main body (T1) which is inserted; and a second stopper (L) disposed at a predetermined part of the interior of the housing of the main body of the image forming apparatus for stopping, at a predetermined insertion stroke position, the developing unit main body (G1) which is inserted, the positions where the toner cartridge main body (T1) and the developing unit main body (G1) are respectively stopped by the first and second stoppers (L), being different from each other such that the lower shutter member (SS) opens the lower toner falling aperture (GU2) before the upper shutter member (US) opens the upper toner falling aperture (TC2) and that the upper shutter member (US) closes the upper toner falling aperture (T2) before the lower shutter member (SS) closes the lower toner falling aperture (GU2) when the developing unit main body (G1) and the toner cartridge main body (T1) connected thereto are integrally inserted in and removed from the interior of the housing.

Inventors: FUJISAWA SHUJI, KOMAKI SUSUMU, FUJISAWA, SHUJI, KOMAKI, SUSUMU, FUJISAWA, SHUJI, C/O MITA INDUSTRIAL CO., LTD., Komaki, Susumu, c/o Mita Industrial Co., Ltd.
Applicants: KYOCERA MITA CORP, KYOCERA MITA CORPORATION
Application year: 1993
Main classification: G03G15
IPC codes: G03G15