Abstract:
A toner container mountable to a main assembly of an electrophotographic image forming apparatus includes a toner containing portion for containing toner; a rotatable toner stirring member for stirring the toner contained in the toner containing portion; a helical gear for receiving driving force for rotating the stirring member, the helical gear being movable in a thrust direction which is substantially crossing with a direction of rotation thereof; an opposite member opposed to an internal surface of the toner containing portion with a gap therebetween, the opposite member being notable together with the helical gear; wherein thrust force produced when the helical gear is rotated with the opposite member being spaced from the internal surface of toner containing portion, is oriented in a direction from outside to inside of the toner containing portion.

Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to a toner container, a process cartridge and an image forming apparatus usable with the process cartridge. 
     Here, the image forming apparatus includes an electrophotographic copying machine, an electrophotographic printer (for example, LED printer, laser beam printer), and electrophotographic facsimile machine, an electrophotographic word processor, and the like. 
     The term process cartridge refers to a cartridge having as a unit, an electrophotographic photosensitive member, and charging means, developing means and cleaning means, which is detachably mountable to the main assembly of an image forming apparatus. It may include as a unit an electrophotographic photosensitive member and at least one of the following: charging means, developing means and cleaning means. It may include as a unit developing means and an electrophotographic photosensitive member. 
     An image forming apparatus using an electrophotographic process is known which is used with a process cartridge. This is advantageous in that the maintenance operation can be, in effect, carried out by the users thereof without expert service persons, and therefore, the operativity can be remarkably improved. Therefore, this type is now widely used. 
     The toner container (hereinafter, T container) of this type of electrophotographic image forming apparatus comprises a developer (toner) stirring means, for example, a stirring plate or a stirring rod, which is driven by a force externally transmitted, by way of gears and the like, to a stirring gear which supports one end of the toner stirring rod. The stirring gear is supported by the toner container or a like by the boss portion. Between the toner container wall and the stirring gear, a sealing member composed of woolen felt or the like is placed to prevent the toner contained in the toner container from leaking out. The stirring gear is formed of resin material such as POM, and is attached to the toner container by snap-fitting. As for the transmission of the driving force to the stirring gear, the driving force from an unillustrated motor is transmitted to the actual spur gear portion of the stirring gear by way of a gear train or the like. 
     SUMMARY OF THE INVENTION 
     The present invention is the result of the further development of the conventional art described above. 
     Accordingly, a primary object of the present invention is to provide a toner container, a process cartridge, and an electrophotographic image forming apparatus, in which toner particles are not aggregated into coarse toner particles by the contact between the internal surface of the toner container wall, and a component (for example, a retainer member such as a retainer ring) disposed within the toner container in a manner to oppose the internal surface of the toner container. 
     Another object of the present invention is to provide a toner container, a process cartridge, and an electrophotographic image forming apparatus, in which toner particles are not aggregated into coarse toner particles by the heat generated by the friction between the internal surface of the toner container wall and a component (for example, a regainer member such as a retainer ring), which occurs as the component opposing the internal surface of the toner container wall is rotated in contact with the surface of the toner container wall. 
     Another object of the present invention is to provide a toner container, a process cartridge, and an electrophotographic image forming apparatus, which are inexpensive, yet capable of producing a desirable image. 
     Another object of the present invention is to provide a toner container, a process cartridge, and an electrophotographic image forming apparatus, which have a structure in which, when a helical gear is rotated, the thrust generated by the rotation of the helical gear is directed inward of the toner container in order to maintain a gap between the internal surface of the toner container wall, and a rotary component disposed within the toner container in such a manner to oppose the internal surface of the toner container wall. 
     These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a horizontal section of the toner stirring portion in the first embodiment of the present invention, depicting the general structure thereof. 
     FIG. 2 is a horizontal section of the stirring gear in the first embodiment of the present invention. 
     FIG. 3 is a vertical section of the image forming apparatus in the first embodiment of the present invention, depicting the general structure thereof. 
     FIG. 4 is a vertical section of the process cartridge in the first embodiment of the present invention, depicting the general structure thereof. 
     FIG. 5 is an external perspective view of the process cartridge in the first embodiment of the present invention. 
     FIG. 6 is a vertical section of the process cartridge and image forming apparatus in the first embodiment of the present invention, depicting the way the former is installed into, or removed from, the latter. 
     FIG. 7 is a horizontal section of the toner stirring portion in the second embodiment of the present invention, depicting the general structure thereof. 
     FIG. 8 is a horizontal section of the toner stirring portion of the third embodiment of the present invention, depicting the general structure thereof. 
     FIG. 9 is a vertical section of the process cartridge in the third embodiment of the present invention, depicting the general structure thereof. 
     FIG. 10 is a horizontal section of the toner stirring portion in the fourth embodiment of the present invention, depicting the general structure thereof. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments 
     Hereinafter, the embodiments of the present invention will be described with reference to the drawings. 
     In this embodiment, the term, &#34;longitudinal direction&#34;, means the horizontal direction perpendicular to the direction in which a recording medium is conveyed in an electrophotographic image forming apparatus, and it means the same when used in the description of a process cartridge. 
     Embodiment 1 
     First, the general structures of a typical electrophotographic image forming apparatus (hereinafter, image forming apparatus), and a typical process cartridge, and then, the structure of the stirring means, will be described. 
     (General Structure) 
     Referring to FIGS. 3-6, the general structure of a typical image forming apparatus, and a typical process cartridge, will be described. FIG. 3 depicts the general structure of an image forming apparatus in which a process cartridge has been installed. FIGS. 4 and 5 depict the structure of a process cartridge. FIG. 6 depicts an image forming apparatus, the cover of which is open, and a process cartridge ready to be installed, depicting the way the latter is installed into the former. 
     Referring to FIG. 3, an image forming apparatus A forms an image on a recording medium through an electrophotographic image forming process. In this process, a toner image is first formed on an electrophotographic photosensitive member (hereinafter, photosensitive drum) 7 in the form of a drum. In synchronism with toner image formation, a recording medium 2 placed in a feeder tray 3a is fed into the image forming apparatus by a conveying means which comprises a pickup roller 3b, a conveyer roller 3c, and the like. Next, the toner image formed on the photosensitive drum 7, which is contained in a process cartridge, is transferred onto the recording medium 2 by means of applying voltage to a transfer roller 4 as a transferring means. Then, the recording medium 2 having received the toner image is conveyed to a fixing means 5 by a guide 3d. The fixing means 5 comprises a driving roller 5a, and a fixing roller 5b which contains a heater. It applies heat and pressure to the recording medium 2 while the recording medium 2 is passed through the fixing means 5. As a result, the toner image having transferred onto the recording medium 2 is fixed to the recording medium 2. Thereafter, the recording medium 2 is conveyed by discharge rollers 3e and 3f, the recording medium 2 being inverted while conveyed, and then, is discharged into a delivery tray 6. 
     Referring to FIGS. 3-5, in the process cartridge B, the photosensitive drum 7 is rotated, and the surface of the photosensitive drum 7 is uniformly charged by applying voltage to a charge roller 8 as a charging means. Next, a laser beam modulated in accordance with image data is projected from an optical system 1 onto the photosensitive drum 7 through an exposure opening 9 to form a latent image. The thus formed latent image is developed by toner, using a developing means 10. More specifically, the charge roller 8 is placed in contact with the photosensitive drum 7 to charge the photosensitive drum 7. The developing means 10 supplies toner onto the peripheral surface of the photosensitive drum 7 to develop the latent image formed on the photosensitive drum 7. The optical system 1 comprises a laser diode 1a, a polygon mirror 1b, a lens 1c, and a deflective mirror 1d. 
     The developing means 10 comprises a toner chamber 10a, and a development chamber 10b. Before the process cartridge B is used for the first time, the opening 10k which connects the toner chamber 10a and the development chamber 10b is sealed with a sealing member 10m in the form of film, toner T being sealed in the toner chamber 10a. When the cartridge B is used for the first time, the sealing member 10m is removed by the user to allow the toner T in the toner chamber to be sent into the development chamber 10b. In the toner chamber 10a, the toner is stirred by a stirring rod 10e. As the toner is stirred, it is sent into the development chamber 10b, in which a development roller 10c containing a stationary magnet is rotated. As the developing roller 10c is rotated, the toner is adhered onto the peripheral surface of the development roller 10c, and then, is formed into a toner layer by a development blade 10d. During this process, the toner receives triboelectric charge. As the development roller 10c is further rotated, the toner is carried to a developing station, that is, where the peripheral surface of the photosensitive drum 7 comes closest to the peripheral surface of the development roller 10c. In the development station, the toner transfers onto the photosensitive drum 7 in accordance with the latent image, developing thereby the latent image into a toner image, a visible image. 
     Next, voltage having the polarity opposite to that of the toner is applied to the transfer roller 4 to transfer the toner image formed on the photosensitive drum 7 onto the recording medium 2. Thereafter, the toner remaining on the photosensitive drum 7 is removed by a cleaning means 11. More specifically, during this toner cleaning process, the toner remaining on the photosensitive drum 7 is scraped into a waste toner collector 11b, being collected therein, by the elastic cleaning blade 11a of the cleaning means 11. 
     The aforementioned photosensitive drum 7 and various other components are integrally placed in a cartridge frame formed by joining a toner chamber wall 12, a development chamber wall 13, and a cleaning chamber wall 14; they are integrated into a process cartridge. More specifically, first, the toner chamber wall 12 and the development chamber wall 13 are welded together to form a toner chamber 10a and a development chamber 10b. Then, the development roller 10c and the development blade 10d are disposed in the development chamber 10b, whereas the photosensitive drum 7, the charge roller 8, and the various components which constitute the cleaning means 11, are mounted on the cleaning chamber wall 14. Thereafter, the toner chamber wall 12 and the cleaning chamber wall 4 are joined in a manner to be pivotable relative to each other, comprising the process cartridge B. 
     The process cartridge B is provided with an exposure opening 9 through which a light beam reflecting image data is projected onto the photosensitive drum 7, and a transfer opening 15 through which the photosensitive drum 9 opposes the recording medium 2 so that the toner image formed on the photosensitive drum 7 can be transferred onto the recording medium 2. Also, the process cartridge 7 is provided with shutters 16a and 16b for exposing or covering the opening 19 and 15, respectively. 
     As for the image forming apparatus A, referring to FIG. 6, a cover 18 is pivotally openable about an axis 19 and is attached to an apparatus main assembly 17. As the cover 18 is opened, an unillustrated guiding member for guiding the process cartridge B is exposed, and the process cartridge B is installed into, or removed from., the apparatus main assembly 7 along this guiding member by an operator. As the process cartridge B is installed into the apparatus main assembly 17, a drum gear 7a (helical gear illustrated in FIGS. 1, 7, 8 and 10) solidly fixed to one of the longitudinal ends of the photosensitive drum 7 meshes with the driving gear AG (helical gear illustrated in FIGS. 1, 7, 8 and 10) of the apparatus main frame 17, readying the process cartridge B to be driven by the drum gear 7a which is driven by the driving gear AG to which the driving force is transmitted from a power source, a motor, through power transmittion members. 
     (Toner Stirring Structure in Toner Chamber) 
     FIG. 1 depicts the structure of the toner stirring portion. FIG. 2 is a longitudinal section of the stirring gear. The structure of the toner stirring portion will be described with reference to these two drawings. 
     Referring to FIG. 1, a stirring rod 10e is shaped like a crank shaft, one end of which is fixed to, being thereby supported by, a stirring gear 10f, and the other end of which is supported by a development chamber wall 12, so that it is rotated through the toner filled in the toner chamber 10a as the stirring gear 10f is rotated. The helical tooth portion 1011 of the stirring gear 10f is meshed with a helical gear 10j which receives a driving force from the drum gear 7a solidly fixed to the end of the photosensitive drum 7. It should be noted here that the stirring gear 10f with helical teeth is attached to the toner chamber wall 12 in such a manner that it is movable in the thrust direction substantially perpendicular to the rotational direction thereof. This is because production and/or assembly errors involving the helical gear and the like components must be taken into consideration. Further, the stirring gear 10f with helical teeth is afforded a play that allows it to move in the thrust direction, with the boss portion 10f3 of the stirring gear sliding on the internal surface of a bearing 12a1. 
     Referring to FIG. 2, the stirring gear 10f comprises the helical tooth portion 10f1, a thrust-bearing portion 10f2 which is one of the inward facing surfaces of the stirring gear 10f, a cylindrical boss portion 10f3 having a smaller diameter than the external diameter of the helical tooth portion 10f1, a cylindrical sealing portion 10f4 having a smaller diameter than the boss portion 10f3, a groove portion 10f5 on the inward side of the sealing portion 10f4, and an end portion 10f9 with a hollow 10f6. This hollow 10f6 is constituted of a center hole portion 10f7 in which the journal portion 10e1 of the stirring rod 10e is fitted, and a groove portion 10f8 which has a perfect width for the arm portion 10e2 of the stirring rod 10e. 
     Referring again to FIG. 1, the boss portion 10f3 is rotatively supported by the internal surface 12a1, a bearing surface, of the cylindrical projection 12a of the toner chamber wall 12. 
     The groove portion 10f5 and the end portion 10f9 with the hollow 10f6 are the portions which project into the toner chamber 10a after the stirring gear 10f is attached to the toner chamber wall 12. In the hollow 10f6, the journal 10e1 at one end of the stirring rod 10e, and the arm portion 10e2 continuous with the journal 10e1, are fitted. The groove portion 10f5 is situated to afford the stirring gear 10f a slight movement in the thrust direction even after the stirring gear 10f is attached to the toner chamber wall, and an E-shaped retainer ring 10g for regulating the movement of the stirring gear in the axial direction is fitted in the groove portion 10f5. More specifically, referring to FIG. 1, the E-shaped retainer ring is such a retainer that prevents the stirring gear 10f from moving leftward too far and slipping out of the toner chamber wall 12 after assembly, yet affords the stirring gear slight movement in the thrust direction. 
     The distance K1 between the thrust-bearing surface 10f2, and the left end vertical surface of the groove portion 10f5 in which the retainer ring 10g is fitted, is greater than the distance K2 between the thrust-bearing surface 10f2 and the internal surface 12b of the toner chamber wall 12. 
     In order to prevent the toner T from leaking out of the toner chamber 10a, a sealing member 10h composed of rubber or the like material is fitted around the cylindrical sealing portion 10f4 in such a manner that the lip portion 10h1 of the sealing member 10h remains in contact with the peripheral surface of the cylindrical sealing portion 10f4, and the peripheral surface 10h2 of the sealing member 10h remains in contact with the internal surface 12a1 of the cylindrical projection 12a. 
     The helical tooth portion 10f1 and the thrust-bearing portion 10f2 are outside the toner chamber 10a, and the force which drives the stirring rod 10e is transmitted to the helical tooth portion 10f1 from the helical gear 10j meshed therewith. The teeth of the helical gear 10j are angled toward the right, and the rotational direction of the helical gear 10j is counterclockwise (direction indicated by an arrow mark A2 in FIG. 1) as seen from outside the toner chamber 10a. On the other hand, the helical teeth of the stirring gear 10f are angled to the left, and the rotational direction of the stirring gear 10f is opposite to that of the helical gear 10j, that is, the clockwise direction (direction indicated by an arrow mark A1 in FIG. 1) as seen from outside the toner chamber 10a. Also in FIG. 1, a stopper 10s is provided to regulate the leftward movement of the helical gear 10j. 
     With the pertinent components being disposed in the above described positional relation, as the driving force is transmitted from the helical gear 10j to the tooth portion 10f1 of the stirring gear 10f through a gear train, a thrusting force is generated due to the way the teeth are cut on the stirring gear 10f and the helical gears 10f. As for the direction of the thrusting force, the helical gear 10j generates thrusting force in the leftward direction of FIG. 1, and the stirring gear 10f generates in the rightward direction, that is, the direction to thrust the stirring gear 10f toward the toner chamber 10a. If, at this time, the helical gear 10j is not in contact with the stopper 10s, the helical gear 10j moves until it comes in contact with the stopper 10s, and remains in contact with it. It should be noted here that the aforementioned positional relations among the pertinent components are such that even in this condition, a space large enough to prevent the sealing member 10h from being compressed and bent toward the axis of the stirring gear 10f is secured as illustrated in FIG. 1 (L1&gt;L2, wherein L1 is the dimension, in the axial direction of the stirring gear 10f, of the space in which the sealing member 10f2 is accommodated, and L2 is the dimension of the sealing member 10h in the same direction). As long as the thrust-bearing portion 10f2 remains in contact with the thrust-bearing portion 12a2 of the cylindrical projection 12a, the retainer ring 10g fitted in the groove portion 10f5 cannot come in contact with the internal surface of the toner chamber wall 12, and in this condition, the stirring gear 10f is rotated in the direction of an arrow mark A3 in the FIG. 4, and therefore, the stirring rod 10e is rotated in the same direction to stir the toner T. 
     (Effects) 
     With the above described structure in place, the retainer ring never comes in contact with the toner chamber wall, and therefore, the phenomenon that the toner becomes coarse due to the heat generated by the friction between the retainer ring and the toner chamber wall never occurs. As a result, it is possible to always produce a desirable image. 
     Embodiment 2 
     FIG. 7 depicts the structure of the toner stirring portion in the second embodiment in which the groove portion 10f5 and the E-shaped retainer ring 10g illustrated in FIG. 1 are not present. In other words, in this embodiment, a means, such as a retainer ring, for preventing the stirring gear 10f from slipping out of the toner chamber wall 12 is eliminated, and therefore, it never occurs that the internal surface 12b of the toner chamber wall 12 makes contact with the means for retaining the stirring gear 10f. Even without a dedicated retaining means, the stirring gear 10f does not slip out of the toner chamber wall 12, because the meshing between the stirring gear 10f the helical gear 10j, and the presence of the resistance from the gear train meshed with the helical gear 10j, provides the stirring gear 10f with a force which works in the direction to retain the stirring gear 10f; in other words, the helical gear 10j serves as a stopper, the retaining means, for the stirring gear 10f. 
     (Effects) 
     Without a retainer such as the E-shaped retainer ring in the preceding embodiment, there is no chance that toner is sandwiched between the retainer and the toner chamber wall 12, and rubbed by them. Therefore, the phenomenon that toner becomes coarse is reliably prevented to produce a desirable image, and also, the production cost is reduced. 
     Embodiment 3 
     In the preceding two embodiments, the moving member, that is, the stirring rod 10e, was disposed within the toner chamber 10a. However, the dispersion of the moving member does not need to be in the toner chamber 10a; it may be disposed in the development chamber 10b or the waste toner collector 11b, as a stirring rod 10i or as waste toner conveying member 11c, which are, respectively, designed to stir the toner, as shown in FIG. 9. 
     For example, FIGS. 8 and 9 depict an embodiment in which the moving member is the waste toner conveying member 11, and the container in which the moving member is disposed is the waste toner collector 11b. In FIG. 9, the stirring rod 10i which moves in the development chamber 10b is illustrated in addition to the waste toner conveying member 11c. The stirring rod 10i rotates clockwise (direction indicated by an arrow mark A4) to stir the toner T in the development chamber 10b. The waste toner conveying member 11c comprises an axis portion 11c1, and a conveying portion 11c2 radially fixed to the axis portion Ilcl, as shown in FIG. 8. It rotates in the direction indicated by an arrow mark A5 in FIG. 9 to convey the waste toner, which has been scraped off by the cleaning blade 11a, deeper into the rear portion of the waste toner collector 11b. The structures of the other portions are the same as those described in the first embodiment. 
     (Effects) 
     The phenomenon that unwanted lines appear in a finished image, due to failure in cleaning the photosensitive drum 7 caused by the coarse toner particles created in a cleaning means container, can be prevented, and therefore, it is possible to always produce a desirable image. 
     Embodiment 4 
     The structure of the toner stirring portion in this fourth embodiment is similar to that in the third embodiment, except for the lack of the retainer ring 10g. 
     Also in this fourth embodiment, the groove portion 10f5 and the E-shaped retainer ring 10g are unnecessary, as they were in the second embodiment. FIG. 10 depicts the structure of the toner stirring portion in this embodiment. In FIG. 10, the functional portions identical to those illustrated in FIG. 8 will be designated with the same referential symbols in order to omit their description. 
     (Effects) 
     Cleaning failure does not occur, and therefore, it is possible to always produce a desirable image, and in addition, to reduce production cost for the apparatus. 
     The following should be noted here. That is, in this specification of the present invention, &#34;toner container&#34; refers to any of the following: a toner container with a framed structure (toner chamber frame) which stores the toner, that is, developer, without releasing it into a development chamber until process cartridge usage begins; a development chamber frame (development chamber wall) which constitutes a development chamber into which the toner within the toner container is delivered as the process cartridge usage begins; and a cleaning means container in which waste toner is collected. 
     As described above, according to the present invention, the phenomenon that toner or waste toner in a container becomes coarse due to the heat generated by the friction within the container does not occur, and therefore, a desirable image can be produced. 
     Further, a stirring gear is properly retained at a predetermined position only by the force generated in the thrust direction by the helical tooth portion thereof, and therefore, not only can the above effects be obtained, but also, the production cost for an image forming apparatus can be reduced. 
     Further, when the present invention is applied to a cleaning means, cleaning failure can be prevented, and therefore, a desirable image is always produced. 
     While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.