Abstract:
A developer collection container includes: a developer collection container main body that forms a developer collection chamber in which developer is collected; a first developer conveyance member, provided inside the developer collection container main body, that conveys the developer by rotating about a shaft; and a second developer conveyance member, provided below the first developer conveyance member with respect to a gravitational direction in the developer collection container main body, that conveys the developer by rotating about a shaft, the developer collection container main body having a collected developer introduction member that introduces the developer to the developer collection chamber being provided between the first developer conveyance member and the second developer conveyance member with respect to the gravitational direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2010-054212 filed Mar. 11, 2010. 
       BACKGROUND 
     Technical Field 
       [0002]    The present invention relates to a developer collection container and an image forming apparatus. 
       SUMMARY 
       [0003]    According to an aspect of the present invention, there is provided a developer collection container including: a developer collection container main body that forms a developer collection chamber in which developer is collected; a first developer conveyance member, provided inside the developer collection container main body, that conveys the developer by rotating about a shaft; and a second developer conveyance member, provided below the first developer conveyance member with respect to a gravitational direction in the developer collection container main body, that conveys the developer by rotating about a shaft, the developer collection container main body having a collected developer introduction member that introduces the developer to the developer collection chamber being provided between the first developer conveyance member and the second developer conveyance member with respect to the gravitational direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
           [0005]      FIG. 1  is a perspective diagram showing an image forming apparatus to which an exemplary embodiment of the present invention is applied; 
           [0006]      FIG. 2  is a cross-sectional diagram showing the image forming apparatus to which the exemplary embodiment of the present invention is applied; 
           [0007]      FIG. 3  is a cross-sectional diagram of a photoreceptor unit; 
           [0008]      FIG. 4  is a cross-sectional diagram of a developing device; 
           [0009]      FIG. 5  is a cross-sectional diagram along a line V-V in  FIG. 4 ; 
           [0010]      FIG. 6  is a schematic diagram of a developer collection passage and its peripheral structure; 
           [0011]      FIG. 7  is a perspective diagram of a developer collection container; 
           [0012]      FIG. 8  is a cross-sectional diagram of the developer collection container viewed from a side surface direction; and 
           [0013]      FIG. 9  is a cross-sectional diagram of the developer collection container viewed from a front side. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    An exemplary embodiment of the present invention will be described based on the drawings. 
         [0015]      FIG. 1  is a perspective diagram showing an image forming apparatus  10  as an exemplary embodiment of the present invention.  FIG. 2  is a cross-sectional diagram showing the image forming apparatus  10 . 
         [0016]    The image forming apparatus  10  has an image forming apparatus main body  12 . A frontward opening/closing member  16  opened/closed frontward (rightward in  FIG. 2 ) via a hinge  14  is attached to the image forming apparatus main body  12 . Further, an upward opening/closing member  20  opened/closed upward via a hinge  18  to the image forming apparatus main body  12 . 
         [0017]    An operation unit  22  is provided in front part of the image forming apparatus main body  12 . The operation unit  22  has ten keys to input the number of recording media for image formation, a start key operated at the start of image formation and the like. Note that a recording medium is a normal paper sheet, an OHP sheet or the like on which an image is finally formed. 
         [0018]    A supply opening/closing member  24  is attached frontward openably/closably to the frontward opening/closing member  16 . At normal times, the supply opening/closing member  24  is closed with respect to the frontward opening/closing member  16 , and the supply opening/closing member  24  is opened when the recording media are supplied to a sub conveyance passage  46  to be described later. 
         [0019]    The upward opening/closing member  20 , in which a recording medium where an image is formed is discharged on its upper surface, is used as a discharge unit. A sub opening/closing member  26  openable/closable with respect to the upward opening/closing member  20  is attached to the upward opening/closing member  20 . The sub opening/closing member  26  can be opened/closed independently of the upward opening/closing member  20 . In a state where the upward opening/closing member  20  is closed with respect to the image forming apparatus main body  12 , the sub opening/closing member  26  can be opened with respect to the upward opening/closing member  20 . 
         [0020]    The upward opening/closing member  20  is opened when photoreceptor units  86 Y,  86 M,  86 C and  86 K and a developer collection container  110 , to be described later, are attached/removed in/from the image forming apparatus main body  12 . 
         [0021]    When the frontward opening/closing member  16  is opened prior to the opening of the upward opening/closing member  20 , an intermediate transfer belt  92  and the like to be described later, attached to the upward opening/closing member  20 , can be prevented from interfering with the frontward opening/closing member  16 . 
         [0022]    When the frontward opening/closing member  16  is closed, the upward opening/closing member  20  is closed prior to the closing of the frontward opening/closing member  16 . 
         [0023]    In a lower position in the image forming apparatus main body  12 , a recording medium supply device  30  to supply the recording medium to an image forming unit  70  to be described later is attached. The recording medium supply device  30  can be pulled out to the front side of the image forming apparatus main body  12  (right side in  FIG. 2 ). In a state where the recording medium supply device  30  is pulled out of the image forming apparatus main body  12 , the recording media are plenished. 
         [0024]    The recording medium supply device  30  has a recording medium container  32  which holds recording media such as normal paper sheets in a stacked state. Further, the recording medium supply device  30  has a conveyance roller  34  to pick up a top recording medium held in the recording medium container  32  and convey the picked recording medium toward the image forming unit  70 , and a retard roller  36  to retard the recording medium so as to prevent multi-feed of plural recording media in an overlapped state to the image forming unit  70 . 
         [0025]    A conveyance passage  40  used for conveyance of the recording medium is formed in the image forming apparatus main body  12 . The conveyance passage  40  has a main conveyance passage  42 , a reversing conveyance passage  44  and a sub conveyance passage  46 . 
         [0026]    The main conveyance passage  42  conveys a recording medium supplied from the recording medium supply device  30  to the image forming unit  70 , and discharges the recording medium on which an image is formed to the outside the image forming apparatus main body  12 . Along the main conveyance passage  42 , sequentially from an upstream side in a conveyance direction of the recording medium, the conveyance roller  34  and the retard roller  36 , a registration roller  52 , a second transfer roller  96  to be described later, a fixing device  102  to be described later, and a discharge roller  54 , are provided. 
         [0027]    The registration roller  52  temporarily stops an end of the recording medium conveyed form the side of the recording medium supply device  30 , and sends the recording medium toward the second transfer roller  96  at timing of image formation. 
         [0028]    The discharge roller  54  discharges a recording medium on which respective color toner are fixed with a fixing device  102  to be described later to the outside the image forming apparatus main body  12 . 
         [0029]    A reversing conveyance passage  44  is a conveyance passage to resupply a recording medium, where a developer image is formed on one surface, while reversing the recording medium, toward the image forming unit  70 . Along the reversing conveyance passage  44 , for example, two reversing conveyance rollers  56  and  58  are provided. 
         [0030]    When the recording medium is conveyed from the main conveyance passage  42  to the discharge roller  54 , and the discharge roller  54  reverse-rotates in a state where the rear end of the recording medium is held with the discharge roller  54 , the recording medium is supplied to the reversing conveyance passage  44 . The recording medium supplied to the reversing conveyance passage  44  is conveyed to a position upstream of the registration roller  52  with the reversing conveyance rollers  56  and  58 . 
         [0031]    The sub conveyance passage  46  is a conveyance passage to supply a special recording medium, which has e.g. size and/or paper quality different from that of the recording media contained in the recording medium supply device  30 , to the image forming unit  70 . The recording medium is supplied from the front side of the image forming apparatus main body  12  to the sub conveyance passage  46  in a state where the supply opening/closing member  24  is opened. The sub conveyance passage  46  is provided with a conveyance roller  60  to convey the recording medium supplied to the sub conveyance passage  46  toward the image forming unit  70  and a retard roller  62  to retard the recording medium supplied to the sub conveyance passage  46  so as to prevent multi-feed of plural recording media in an overlapped state to the image forming unit  70 . 
         [0032]    The image forming unit  70  which forms an image on a recording medium is provided in the image forming apparatus main body  12 . The image forming unit  70  has, for example, four developer image forming units  80 Y,  80 M,  80 C and  80 K, an optical writing device  82  and a transfer device  84 . 
         [0033]    The developer image forming units  80 Y,  80 M,  80 C and  80 K respectively form developer images using Y (yellow), M (magenta), C (cyan) and K (black) developers. 
         [0034]    Note that in the following description, the image forming units may be generically referred to as a developer image forming unit  80  without alphabet Y, M, C or K. Similarly, other constituent elements corresponding to respective colors may be generically referred (as photoreceptor unit  86 , a developing device  88 , and the like). 
         [0035]    The developer image forming units  80 Y,  80 M,  80 C and  80 K respectively have photoreceptor units  86 Y,  86 M,  86 C and  86 K and developing devices  88 Y,  88 M,  88 C and  88 K. 
         [0036]    The photoreceptor units  86  are arrayed sequentially from the rear side of the image forming apparatus main body  12  (left side in  FIG. 2 ) as the photoreceptor units  86 Y,  86 M,  86 C and  86 K. 
         [0037]    The photoreceptor units  86 Y,  86 M,  86 C and  86 K are respectively used as an image forming structure and respectively have photoreceptor drums  90 Y,  90 M,  90 C and  90 K. 
         [0038]    The photoreceptor drum  90  is used as an image holder. 
         [0039]    The developing devices  88 Y,  88 M,  88 C and  88 K develop latent images formed on the corresponding photoreceptor drums  90 Y,  90 M,  90 C and  90 K using respectively contained Y, M, C and K developers. 
         [0040]    The optical writing device  82  which is used as a latent image forming device irradiates the photoreceptor drum  90  with light, thereby forms latent images on the respective surfaces of the photoreceptor drums  90 Y,  90 M,  90 C and  90 K. 
         [0041]    The transfer device  84  has the intermediate transfer belt  92  used as a transfer body, first transfer rollers  94 Y,  94 M,  94 C and  94 K used as first transfer devices, a second transfer roller  96  used as a second transfer device, and a cleaning device  98 . 
         [0042]    The intermediate transfer belt  92  which is an endless belt is supported with e.g. five support rollers  92   a ,  92   b ,  92   c ,  92   d  and  92   e , rotatably in an arrow direction in  FIG. 2 . At least one of the support rollers  92   a ,  92   b ,  92   c ,  92   d  and  92   e  is connected to a motor (not shown), and rotated upon reception of driving transmitted from the motor, to rotate-drive the intermediate transfer belt  92 . 
         [0043]    The first transfer rollers  94 Y,  94 M,  94 C and  94 K transfer developer images, formed on the surfaces of the photoreceptor drums  90 Y,  90 M,  90 C and  90 K by the respectively corresponding developing devices  88 Y,  88 M,  88 C and  88 K, onto the intermediate transfer belt  92 . 
         [0044]    The second transfer roller  96  transfers the Y, M, C and K developer images transferred onto the intermediate transfer belt  92  to a recording medium. 
         [0045]    The cleaning device  98  has a scraping member  100  which, after transfer of the respective color developer images with the second transfer roller  96  to the recording medium, scrapes toner as respective color developers remaining on the surface of the intermediate transfer belt  92 . The toner scraped with the member  100  is collected into the main body of the cleaning device  98 . 
         [0046]    The cleaning device  98  can be attached/removed in/from the image forming apparatus main body  12  via an opening formed by opening the sub opening/closing member  26 . 
         [0047]    Among elements forming the transfer device  84 , the intermediate transfer belt  92 , the support rollers  92   a ,  92   b ,  92   c ,  92   d  and  92   e , the first transfer roller  94 , and the cleaning device  98  are attached to the upward opening/closing member  20 . The second transfer roller  96  of the transfer device  84  is attached to the image forming apparatus main body  12 . 
         [0048]    Further, the fixing device  102  to fix the developer image, transferred with the second transfer roller  96 , onto the recording medium to the recording medium, is provided in the image forming apparatus main body  12 . 
         [0049]    The developer collection container  110  is provided in the image forming apparatus main body  12 . The developer collection container  110  is used as a discharged developer collection container to collect the developer discharged from at least one of the plural developer image forming units  80 Y,  80 M,  80 C and  80 K. 
         [0050]    In the present exemplary embodiment, the developers discharged from all the four developer image forming units  80 Y,  80 M,  80 C and  80 K are collected into the developer collection container  110 . More particularly, in the present exemplary embodiment, the developers discharged from the respective developing devices  88 Y,  88 M,  88 C and  88 K of the developer image forming units  80 Y,  80 M,  80 C and  80 K are collected into the developer collection container  110 . 
         [0051]    The developers discharged from the developing devices  88 Y,  88 M,  88 C and  88 K are conveyed in a developer collection passage  170  (see  FIG. 6 ) to be described later, provided in the image forming apparatus main body  12 , to the developer collection container  110 . 
         [0052]    The developer collection container  110  is not limited to the structure in the present exemplary embodiment where the developer discharged from the developing device  88  of the developer image forming unit  80  is collected into the developer collection container  110 . In place of this structure, or in addition to this structure, it may be arranged such that the developer discharged from the developer image forming unit  80  and discharged from another device than the developing device (for example, the developer removed from the surface of the photoreceptor drum  90 ) is collected into the developer collection container  110 . 
         [0053]    In the present exemplary embodiment, the developer collection container  110  is integrally formed with the photoreceptor unit  86 K, and attached/removed in/from the image forming apparatus main body  12  integrally with the photoreceptor unit  86 K. 
         [0054]    The developer collection container  110  is not limited to this structure, but in place of the structure where the developer collection container  110  is integrally formed with the photoreceptor unit  86 K, it may be arranged such that the developer collection container  110  is integrally formed with any one of the other photoreceptor units  86 Y,  86 M and  86 C and attached/removed integrally with any one of these photoreceptor units  86 Y,  86 M and  86 C. 
         [0055]    Further, it may be arranged such that the developer collection container  110  is not integrally formed with the photoreceptor unit  86  but independently provided. 
         [0056]    Next, the details of the photoreceptor unit  86  will be described. Note that as the photoreceptor units  86 Y,  86 M,  86 C and  86 K have the same structure except that corresponding colors are different, the photoreceptor unit  86 Y will be used as a typical example in the following description. 
         [0057]      FIG. 3  is a cross-sectional diagram of the photoreceptor unit  86 Y. 
         [0058]    The photoreceptor unit  86 Y has a photoreceptor unit main body  122 Y, and the photoreceptor drum  90 Y is attached in the photoreceptor unit main body  122 Y. A part of the photoreceptor drum  90 Y can be exposed to the outside the photoreceptor unit main body  122 Y as an exposed part  124 Y. 
         [0059]    A charging device  126 Y to uniformly charge the surface of the photoreceptor drum  90 Y is attached in the photoreceptor unit main body  122 Y. The charging device  126 Y has a charging roller  128 Y in contact with the photoreceptor drum  90 Y. A latent image is written with the optical writing device  82  (see  FIG. 2 ) on the surface of the photoreceptor drum  90 Y uniformly charged with the charging device  126 Y. 
         [0060]    A scraping member  130 Y used as a cleaning device is attached in the photoreceptor unit main body  122 Y. After Y (yellow) toner as the developer has been transferred with the first transfer roller  94 Y (see  FIG. 2 ) to the intermediate transfer belt  92 , the scraping member  130 Y scrapes the developer remaining on the surface of the photoreceptor drum  90 Y. Further, a collection chamber  132 Y in which the toner scraped with the scraping member  130 Y off the surface of the photoreceptor drum  90 Y is collected is provided in the photoreceptor unit main body  122 Y. 
         [0061]    A shutter  136 Y is attached via a support member  134 Y to the photoreceptor unit main body  122 Y. The support member  134 Y and the shutter  136 Y are used as opening/closing members to open/close by moving between a position to cover the exposed part  124 Y of the photoreceptor drum  90 Y (hereinbelow, referred to as a “covering position”) and a position to expose the exposed part  124 Y from the photoreceptor unit main body  122 Y (hereinbelow, referred to as an “exposing position”).  FIG. 3  shows a state where the support member  134 Y and the shutter  136 Y have moved to the covering position. 
         [0062]    In a state where the photoreceptor unit  86 Y is not attached to the image forming apparatus main body  12 , the support member  134 Y and the shutter  136 Y are in the covering position. Further, in a state where the photoreceptor unit  86 Y is attached to the image forming apparatus main body  12  and the upward opening/closing member  20  is opened with respect to the image forming apparatus main body  12 , the support member  134 Y and the shutter  136 Y are in the covering position. 
         [0063]    In a state where the photoreceptor unit  200  is attached to the image forming apparatus main body  12 , when the upward opening/closing member  20  is closed with respect to the image forming apparatus main body  12 , in accordance with the closing operation of the upward opening/closing member  20 , the support member  134 Y and the shutter  136 Y move to the exposing position. Further, when the upward opening/closing member  20  is opened with respect to the image forming apparatus main body  12 , in accordance with the opening operation of the upward opening/closing member  20 , the support member  134 Y and the shutter  136 Y move to the covering position. 
         [0064]    In this manner, in a state where the photoreceptor unit  86 Y is attached to the image forming apparatus main body  12  and the upward opening/closing member  20  is closed, the support member  134 Y and the shutter  136 Y are in the exposing position. That is, the structure can prevent erroneous contact between the photoreceptor drum  90 Y and the outside in other cases than image forming operation. 
         [0065]    The linkage between opening/closing of the upward opening/closing member  20  and the opening/closing of the support member  134 Y and the shutter  136 Y is realized with a link mechanism (not shown) or the like. 
         [0066]    Next, the details of the developing device  88  will be described. Note that since the developing devices  88 Y,  88 M,  88 C and  88 K have the same structure except that corresponding colors are different, the developing device  88 Y will be used as a typical example in the following description. 
         [0067]      FIG. 4  is a cross-sectional diagram of the developing device  88 Y.  FIG. 5  is a cross-sectional diagram along a line V-V in  FIG. 4 . 
         [0068]    The developing device  88 Y is a two-component type developing device which develops a latent image using two-component developer containing toner and carrier. The developing device  88 Y has a developing device main body  142 Y which contains the developer. 
         [0069]    A developing roller  144 Y used as a developer holder is attached in the developing device main body  142 Y. The developing roller  144 Y rotates in an arrow direction shown in  FIG. 4 , to supply the developer held on its surface to the photoreceptor drum  90 Y (see  FIG. 2 ) and develop a latent image formed on the surface of the photoreceptor drum  90 Y. 
         [0070]    In the developing device main body  142 Y, the space is partitioned into e.g. two spaces with one partition member  146 Y, as developer conveyance passages  148 Y and  150 Y. The developer conveyance passages  148 Y and  150 Y are used as passages to convey the developer in the developing device main body  142 Y. 
         [0071]    In the developer conveyance passages  148 Y and  150 Y, conveyance members  152 Y and  154 Y to convey the developer while stirring the developer are attached. 
         [0072]    A supply hole  156 Y and a discharge hole  158 Y are formed in the developing device main body  142 Y. The developer is supplied from a developer container (not shown) via the supply hole  156 Y into the developing device main body  142 Y. Further, the developer is discharged via the discharge hole  158 Y to the outside of the developing device main body  142 Y. 
         [0073]    In the developing device  88 Y having the above structure, the developer supplied via the supply hole  156 Y in the developing device main body  142 Y is conveyed with the conveyance member  152 Y in the conveyance passage  148 Y, and conveyed with the conveyance member  154 Y in the conveyance passage  150 Y. Then, e.g. some of the developer is finally discharged via the discharge hole  158 Y to the outside of the developing device main body  142 Y. 
         [0074]    In this manner, a new developer is supplied into the developing device main body  142 Y and excessive developer is discharged, thereby developing is performed using the newly supplied developer without continuously using developer containing deteriorated carrier. 
         [0075]      FIG. 6  shows the developer collection passage  170 . 
         [0076]    The developer collection passage  170  has vertical parts  172 Y,  172 M,  172 C and  172 K extending in an approximately vertical direction and a horizontal part  174  connected to these vertical parts  172 Y,  172 M,  172 C and  172 K, extending in an approximately horizontal direction. 
         [0077]    The vertical parts  172 Y,  172 M,  172 C and  172 K have a hollow shape such as a pipe. The upper ends of the vertical parts  172 Y,  172 M,  172 C and  172 K are connected to discharge holes  158 Y,  158 M,  158 C and  158 K of the respectively corresponding developing devices  88 Y,  88 M,  88 C and  88 K. The developers discharged from these discharge holes  158  are dropped in the vertical parts  172  to the horizontal part  174 . The horizontal part  174  is connected to an introduction member  112  of the developer collection container  110 . 
         [0078]    The horizontal part  174  has a hollow shape such as a pipe, in which a conveyance member  176  to convey the developer is inserted in the hollow. The conveyance member  176  receives driving transmitted from a motor M 1  via gears G 1  to G 3 . As the conveyance member  176  rotates with the received driving transmitted from the motor M 1 , the conveyance member  176  conveys the developers drop-conveyed from the vertical parts  172 Y,  172 M,  172 C and  172 K toward the developer collection container  110 . The developers conveyed in the horizontal part  174  are introduced with the introduction member  112  into the developer collection container  110 . 
         [0079]    Next, the details of the developer collection container  110  will be described. 
         [0080]      FIG. 7  is a perspective diagram of the entire developer collection container  110 . Further,  FIG. 8  is a cross-sectional diagram of the developer collection container  110  viewed from a side surface direction.  FIG. 9  is a cross-sectional diagram of the developer collection container  110  viewed from a front side. 
         [0081]    The developer collection container  110  has a developer collection container main body  202 , and a developer collection chamber  204  is formed in the developer collection container main body  202 . 
         [0082]    A part of an inner surface of the developer collection container main body  202  forms a slope  206 . The developer collected in the developer collection container main body  202  slips on the slope  206  and falls toward the bottom of the developer collection chamber  204 . 
         [0083]    In the developer collection container  110 , the developer including both toner and carrier discharged from the developing device  88  is collected, while the toner removed from the surface of the photoreceptor drum  90  is collected into a collection chamber  132  of the photoreceptor unit  86 . 
         [0084]    In the developer collection chamber  204 , an upper conveyance unit  210  and a lower conveyance unit  220  to convey a developer in the developer collection chamber  204  are provided in upper and lower positions in the gravitational direction. 
         [0085]    The upper surface of the developer collection container  110  is a release member. The release member is sealed by attachment of the developer collection container  110  to the photoreceptor unit  86 . Further, the release member may be sealed with a lid. 
         [0086]    The ends of the upper conveyance unit  210  and the lower conveyance unit  220  are projected to the outside of the developer collection container main body  202 , and gears G 4  and G 5  are attached to the projected portions. The upper conveyance unit  210  and the lower conveyance unit  220  receive driving transmitted from a motor M 2  via gears G 4  to G 7 . 
         [0087]    The upper conveyance unit  210  and the lower conveyance unit  220  rotate with the driving transmitted from the motor M 2 , thereby convey the developer introduced from the introduction member  112  to the opposite side to the introduction member  112  (right side in  FIG. 9 , and hereinbelow, referred to as a “rear side”) with respect to a rotation shaft direction of the upper conveyance unit  210  and the lower conveyance unit  220  (hereinbelow, simply referred to as a “rotation shaft direction”). 
         [0088]    The introduction member  112  is provided in an approximately central position with respect to a height direction of the developer collection container main body  202  and at a height between the upper conveyance unit  210  and the lower conveyance unit  220 . Accordingly, the developer discharged from the developing device  88  and conveyed in the developer collection passage  170  is collected from a position between the upper conveyance unit  210  and the lower conveyance unit  220  via the introduction member  112  into the collection container main body  202 . 
         [0089]    The upper conveyance unit  210  has an upper rotation shaft  212 . At least this upper conveyance shaft  212  is provided above the introduction member  112  in the gravitational direction. The upper conveyance shaft  212  is provided with e.g. three spiral-shaped upper conveyance members  214   a ,  214   b  and  214   c  at intervals D 1  and D 2  from the end on the introduction member  112  side. Further, at a rear side end of the upper rotation shaft  212 , a reversing conveyance member  216  in a reverse direction to the upper conveyance member  214  is provided at an interval D 3  from the upper conveyance shaft  212   c.    
         [0090]    Accordingly, when the upper conveyance shaft  212  rotates, the upper conveyance member  214  conveys the developer on the introduction member  112  side in the direction of the rear side, and the reversing conveyance member  216  conveys the developer on the rear side in the direction of the introduction member  112  side. 
         [0091]    Note that when the developer is continuously conveyed to only in the direction of the rear side direction in the developer collection container main body  202 , the developer is densely accumulated on the rear side. As a result, excessive load may be imposed on the rotational driving of the upper conveyance unit  210  and the lower conveyance unit  220 . Accordingly, the reversing conveyance member  216  conveys the developer from the rear side in the direction of the introduction member  112  side, so as to prevent dense accumulation of the developer on the rear side. 
         [0092]    The upper conveyance members  214   a ,  214   b ,  214   c  form a first upper conveyance region R 11 , a second upper conveyance region R 13 , and a third upper conveyance region R 15 . Further, the intervals D 1  to D 3  form a first upper non-conveyance region R 12 , a second upper non-conveyance region R 14  and a third upper non-conveyance region R 16 . The reversing conveyance member  216  forms a reverse conveyance region R 17 . 
         [0093]    The positions in the rotation shaft direction of the upper conveyance unit  210  are in the first upper conveyance region R 11 , the first upper non-conveyance region R 12 , the second upper conveyance region R 13 , the second upper non-conveyance region R 14 , the third upper conveyance region R 15 , the third upper non-conveyance region R 16  and the reverse conveyance region R 17 . 
         [0094]    The lower conveyance unit  220  has a lower rotation shaft  222 . At least this lower rotation shaft  222  is provided below the introduction member  112  in the gravitational direction. The lower conveyance unit  220  is provided with e.g. two spiral-shaped lower conveyance members  224   a  and  224   b  at an interval D 4  from the end on the introduction member  112  side. The lower conveyance member  224   b  is provided at an interval D 5  from the rear side end. 
         [0095]    The lower conveyance members  224   a  and  224   b  have a first lower conveyance region and a second lower conveyance region. Further, the intervals D 4  and D 5  form a first lower non-conveyance region and a second lower non-conveyance region. 
         [0096]    The positions in the rotation shaft direction of the lower conveyance unit  220  are in a first lower conveyance region R 21 , a first lower non-conveyance region R 22 , a second lower conveyance region R 23 , a region R 24  in the rear side from the region R 23  and not overlapped with the reversing conveyance member  216  (region R 17 ) with respect to the rotation shaft direction, and a region R 25  in the rear side from the region R 24 . 
         [0097]    The lower conveyance member  224   b  is provided in a position overlapped with at least the interval D 2  between the upper conveyance member  214   b  and the upper conveyance member  214   c  in the rotation shaft direction. 
         [0098]    Further, the interval D 4  between the lower conveyance member  224   a  and the lower conveyance member  224   b  is provided in a position overlapped with at least a part of the upper conveyance member  214   a  and the interval D 1  between the upper conveyance member  214   a  and the upper conveyance member  214   b  in the rotation shaft direction. 
         [0099]    The details of mutual positional relation between the respective conveyance regions and non-conveyance regions of the upper conveyance unit  210  and the lower conveyance unit  220  will be described using  FIG. 9 . Note that for the sake of explanation, in the respective regions, the introduction member  112  side is represented as “beginning” while the rear side, as “ending”. 
         [0100]    The regions R 11  and R 21 , without disturbing the introduction of developer from the introduction member  112 , start from a position to convey the introduced developer in the direction of the regions R 12  and R 22 . The ending of the region R 11  is on the rear side from the ending of the region R 21 . 
         [0101]    The beginning of the region R 12  is in the rear side from the beginning of the region R 22 . The ending of the region R 12  is on the introduction member  112  side from the ending of the region R 22 . 
         [0102]    The beginning of the region R 13  is on the introduction member  112  side from the beginning of the region R 23 . The ending of the region R 13  is on the introduction member  112  side from the ending of the region R 23 . 
         [0103]    The beginning of the region R 23  is on the introduction member  112  side from the beginning of the region R 15 . The ending of the region R 23  is on the introduction member  112  side from the ending of the region R 15 . 
         [0104]    The beginning of the region R 15  is on the rear side from the beginning of the region R 23 . The ending of the region R 15  is on the rear side from the ending of the region R 23 . 
         [0105]    The beginning of the region R 14  is on the rear side from the beginning of the region R 23 . The ending of the region R 14  is on the introduction member  112  side from the ending of the region R 23 . 
         [0106]    In this manner, the beginning of the second and subsequent upper conveyance regions and the beginning of the second and subsequent lower conveyance regions are alternately arranged on the upper and lower sides with respect to the rotation shaft direction. 
         [0107]    In the present exemplary embodiment, the upper conveyance member  214   a  provided from the respective introduction member  112  side of the upper rotation shaft  212  and the lower rotation shaft  222 , the upper conveyance members  214   b  and  214   c  on the rear side from the lower conveyance member  224   a , and the lower conveyance member  224   b , are provided alternately on the upper and lower sides with respect to the rotation shaft direction. 
         [0108]    Next, the conveyance of the developer collected in the developer collection container main body  202  will be described. The space in the developer collection container main body  202  is partitioned in the rotation shaft direction, from the end of the introduction member  112  side, (1) the region R 21 , (2) the region R 22 , (3) the region R 23 , (4) a region where the region R 24  and the region R 15  overlap each other, (5) the region  16  and (6) region R 25 . 
       (1) Region R 21   
       [0109]    In the region R 21 , the developer discharged from the introduction member  112  is conveyed with the upper conveyance member  214   a  and the lower conveyance member  224   a  to the region R 22 . With this arrangement, accumulation of the developer around the introduction member  112  (region R 21 ) is suppressed. 
       (2) Region R 22   
       [0110]    In the region R 22 , the developer conveyed from the region R 21  is accumulated. 
         [0111]    The developer accumulated to the height of the upper conveyance unit  210  is conveyed with the upper conveyance members  214   a  and  214   b  in the direction of the region R 23 . 
         [0112]    When a range where the developer is temporarily accumulated is provided in the region R 22  adjacent to the region R 21 , in comparison with a case without the present structure, the accumulation of the developer around the introduction member  112  is further suppressed. 
       (3) Region R 23   
       [0113]    In the region R 23 , the developer conveyed from the region R 22  is accumulated. 
         [0114]    The developer accumulated to the height of the lower conveyance unit  220  is conveyed, mainly with the lower conveyance member  224   b , in the direction of the region R 24 . 
         [0115]    In accordance with the accumulated state of the developer in the developer collection container main body  202 , when the developer has been accumulated to the height of the upper conveyance unit  210  in the region R 23 , the developer is conveyed, with the upper conveyance members  214   b  and  214   c  in addition to the lower conveyance member  224   b , in the direction of a range R 4 . 
         [0000]    (4) Region where Region R 24  and Region R 15  Overlap Each Other 
         [0116]    In the region where the region R 24  and the region R 15  overlap each other, the developer conveyed from the region R 23  is accumulated. 
         [0117]    The developer accumulated to the height of the upper conveyance unit  210  is conveyed with the upper conveyance member  214   c  in the direction of the region R 25 . 
         [0118]    When the regions R 23  and R 24  are provided around the center of the developer collection container main body  202 , in comparison with a case without the present structure, local accumulation of the developer at around the central position can be further suppressed. 
       (5) Region  16   
       [0119]    In the region  16 , the developer conveyed from the region where the region R 24  and the region R 15  overlap each other and the developer conveyed from the region R 25  are accumulated. 
         [0120]    The region  16  (interval D 3 ) is the greatest (longest) range among the above regions (1) to (6). Accordingly, the largest amount of developer in the above regions (1) to (6) can be contained in the region  16 . 
         [0121]    When the region  16  is arranged on the rear side from the center of the developer collection container main body  202 , in comparison with a case without the present structure, the developer can be more efficiently contained in the developer collection container main body  202 . 
       (6) Region R 25   
       [0122]    In the region R 25 , the developer conveyed from the region  16  is accumulated. 
         [0123]    The developer accumulated to the height of the upper conveyance unit  210  is conveyed with the reversing conveyance member  216  in the direction of the region  16 . Accordingly, in the region R 25 , dense accumulation of developer can be suppressed. 
         [0124]    Further, since the region R 25  is positioned at the end of the rear side, the accumulated developer may reach the height of the upper conveyance unit  210  before the height in the region  16  becomes the height of the upper conveyance unit  210 . In this case, the reversing conveyance member  216  provided in the upper position conveys the developer to the region R 16  having larger capacity than that in the region R 25 . 
         [0125]    In this manner, in the developer collection container  110 , the developer can be contained even in a position higher than the introduction member  112 . 
         [0126]    In the present exemplary embodiment, the upper conveyance member  214  is partitioned into three parts, while the lower conveyance member  224  is partitioned into two parts. However, the present invention is not limited to this arrangement. The partitioning may be arbitrarily changed in correspondence with the size or the like of the developer collection container  110 . 
         [0127]    Further, the reversing conveyance member  216  may be provided in the both upper conveyance unit  210  and the lower conveyance unit  220 . 
         [0128]    Further, seen from the rotation shaft direction, the rotation shafts of the upper conveyance unit  210  and the lower conveyance unit  220  overlap each other in the vertical direction. However, the rotation shafts may be shifted in the horizontal direction within a range where the developer can be conveyed. For example, when there is no problem in a state where, seen from the rotation shaft direction, at least parts of the upper conveyance unit  210  and the lower conveyance unit  220  may be overlap each other in the vertical direction, the upper conveyance unit  210  and the lower conveyance unit  220  may be shifted in the horizontal direction. 
         [0129]    The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.