Patent Publication Number: US-9423760-B2

Title: Developer accommodating container and image forming apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a developer accommodating container which includes a detecting mechanism that detects the amount of powders within an accommodating container for accommodating powders and an image forming apparatus provided with the developer accommodating container. 
     2. Description of the Related Art 
     In an image forming apparatus having an intermediate transfer belt, a toner image formed on a photosensitive drum is transferred to the intermediate transfer belt and the toner image transferred to the intermediate transfer belt is transferred to a recording material. Then, transfer residual toner remaining on the surface of the photosensitive drum or the intermediate transfer belt is collected by a cleaning member and is collected in an accommodating container via a conveying path through which the collected toner is conveyed. 
     When a predetermined amount of toner is accumulated in the accommodating container, it is necessary to replace the accommodating container. In order to facilitate the replacement of the accommodating container, then, it is necessary to prepare a toner detecting apparatus that determines whether the toner reaches a predetermined amount. The invention relative to such toner detecting apparatus is disclosed in Japanese Patent Laid-Open No. 2000-75749. 
     In Japanese Patent Laid-Open No. 2000-75749, a light emitting element and a light receiving element are provided at one side of a transparent accommodating container and a prism is provided at the other side thereof. Moreover, the invention related to a toner amount detecting apparatus is disclosed which detects whether the toner within the accommodating container reaches a predetermined amount because light of the light emitting element is blocked out in the toner and thus is not detected by the light receiving element. 
     However, according to the invention disclosed in Japanese Patent Laid-Open No. 2000-75749, although the cost is inexpensive, scattered toner is attached on the surface of an inner wall of the accommodating container at which the prism is installed and, accordingly, there is a possibility to erroneously detect that the toner reaches the predetermined amount before the toner reaches the predetermined amount. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problems, it is desirable to provide a developer accommodating container which can reliably detect the amount of powders within an accommodating container without an erroneous detection compared to the related art. 
     A developer accommodating container, comprising:
         an accommodating portion provided with a falling inlet which receives a falling developer;   an optical portion which forms a light path inside the accommodating portion;   a space portion which is provided in the middle of the light path formed by the optical portion and capable of accumulating the developer accommodated in the accommodating portion;   a casing portion which has a cover portion covering the space portion not to flow in the developer to the space portion except a surface of the opposite side which is formed the falling inlet seeing from the space portion, and that has a introducing inlet which can introduce the developer to the space portion from upper position than at least a bottom of the space portion, and that has a discharge outlet which can discharge the developer which is introduced from the introducing inlet at a lower position than the space portion.       

     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view illustrating a structure of an image forming apparatus provided with a powder amount detecting system according to an embodiment of the invention. 
         FIG. 2  is a sectional view of the image forming apparatus taken along another position. 
         FIG. 3  is a sectional view illustrating a structure of an accommodating container. 
         FIG. 4  is a sectional view as seen from a direction indicated by the arrow J in  FIG. 3 . 
         FIG. 5  is a sectional view illustrating a structure of a powder amount detecting system. 
         FIG. 6  is a perspective view illustrating a structure of a blocking member disposed inside the accommodating container. 
         FIG. 7  is a sectional view illustrating a structure of a prism unit. 
         FIG. 8  is a sectional view of the prism unit illustrating a state at the time when toner is introduced. 
         FIG. 9  is a sectional view of the prism unit illustrating a state where the toner is introduced and reaches a detecting region surface. 
         FIGS. 10A and 10B  are structure diagrams illustrating a structure of an accommodating container according to a modified example of the embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, exemplary embodiments of the invention will be described in detail with reference to appended drawings. However, dimensions, materials, shapes, and relative positions of components described in the following embodiments are appropriately modified according to structures or various conditions of an apparatus to which the invention is applied. Therefore, the scope of the invention, unless otherwise specified in particular, is not intended to limit thereto. 
       FIG. 1  is a sectional view illustrating a structure of an image forming apparatus  60  provided with a powder amount detecting system  100  (see  FIG. 5 ) according to an embodiment of the invention. The image forming apparatus  60  is an image forming apparatus using an electrophotographic image forming process. As illustrated in  FIG. 1 , the image forming apparatus  60  includes an image forming apparatus body (hereinafter, simply referred to as an “apparatus body”)  60 A, and an image forming portion  51  is provided in the apparatus body  60 A to form an image. The image forming portion  51  includes a photosensitive drum  611  which is an “image bearing member” and a primary transfer roller  618  which is a “transfer apparatus”. For at least the photosensitive drum  611 , it is contained in a process cartridge and may be configured to be incorporated in the apparatus body  60 A as the process cartridge. The image forming apparatus  60  is an image forming apparatus of a so-called intermediate transfer tandem type in which the image forming portions of four colors are juxtaposed on an intermediate transfer belt  605  and has become a mainstream in recent year because of its superiority in terms of the compatibility with thick sheet or productivity. 
     A recording material S is stored in the form of being stacked on a lift-up apparatus  62  within a recording material storage case  61 . Further, the recording material S is fed according to an image forming timing by a pair of feed rollers  63 . Here, the pair of feed rollers  63  employs a system using a frictional separation by a separation roller. The recording material S fed out by the pair of feed rollers  63  passes through a conveying path  64   a  and is conveyed into a registration roller  65 . 
     The registration roller  65 , which is an apparatus for adjusting a relative position of the recording material S and the image, is fed out a secondary transfer portion after performing a skew correction or a timing correction of the recording material S. The secondary transfer portion is a toner image transferring nip portion for transferring a toner image to the recording material S which is formed by a secondary transfer inner roller  608  and a secondary transfer outer roller  66  facing each other and causes the toner image to adhere onto the recording material S by applying a predetermined pressured force and an electrostatic load bias. 
     The process of forming an image fed to the secondary transfer portion at the same timing as the process of conveying the recording material S to the secondary transfer portion as described above will be described. The image forming portion  51  mainly includes the photosensitive drum  611 , a charging apparatus  612 , an exposure apparatus  609 , a developing apparatus  613 , the primary transfer roller  618 , and a photosensitive cleaner  614 . 
     An electrostatic image is formed on the photosensitive drum  611  of which the surface is uniformly charged in advance by the charging apparatus  612  to rotate in the direction of the arrow D, appropriately through a diffraction unit  610 , by driving the exposure apparatus  609  based on a transmitted signal of image information. The electrostatic image formed on the photosensitive drum  611  is visualized as a toner image on the photosensitive drum  611  through toner development by the developing apparatus  613 . Subsequently, the toner image is transferred onto an intermediate transfer belt  605  by applying a predetermined pressured force and an electrostatic load bias by the primary transfer roller  618 . 
     Moreover, the above-described image forming portion  51  is made up of four sets of yellow (Y), magenta (M), cyan (C) and black (Bk). 
     Next, the intermediate transfer belt  605  will be described. The intermediate transfer belt  605  is stretched by rollers such as a drive roller  606 , a tension roller  607  and the secondary transfer inner roller  608  and is driven in a direction of the arrow B. The image forming processes of the respective colors to be processed in parallel by each image forming mechanism of the above-described Y, M, C and Bk are performed at timing as being superimposed on the toner image of an upstream color primarily transferred onto the intermediate transfer belt  605 . Consequently, the toner image of full color is finally formed on the intermediate transfer belt  605  and is conveyed to the secondary transfer portion. 
     The toner image of full color is secondarily transferred onto the recording material S at the secondary transfer portion with the conveying process of the recording material S and the image forming process, which are described above, respectively. Here also, the transfer residual toner remaining slightly on the intermediate transfer belt  605  is collected by a cleaning apparatus  619  of the intermediate transfer belt  605 , in the same manner, and is conveyed by a conveying path  21  (see  FIG. 2 ), resulting in falling into an accommodating container (accommodating portion)  11  (see  FIG. 2 ) and being stored therein. 
     Subsequently, the recording material S is conveyed to a fixing apparatus  68  by a pre-fixing conveying portion  67 . The fixing apparatus  68  melts and fixes the toner image on the recording material S with the predetermined pressed force due to opposed rollers or belts in addition to heating effect due to a heat source such as a heater. Path selection is performed such that the recording material S having the fixed image obtained as described above is conveyed to either a discharge conveying path  69  for directly discharging onto a discharge tray  600  or to a reverse guide path  2  included in a reverse conveying apparatus  10  when an duplex image forming is required. In a case of requiring the duplex image forming, the recording material S is drawn to a switch-back path  4  from the reverse guide path  2  and then is conveyed again to the image forming portion  51  through a duplex conveying path  3  by forwarding and reversing the rotational direction (i.e., switch-back operation) of a reverse roller  6  to switch front-rear ends of the recording material S. 
       FIG. 2  is a sectional view of the image forming apparatus  60  taken along another position. As illustrated in  FIG. 2 , the apparatus body  60 A is provided with the accommodating container (powder storing container)  11  for accommodating toner T (developer) and the conveying path  21  for conveying the collected toner, which are disposed therein, respectively. The transfer residual toner remaining slightly on the above-described photosensitive drum  611  is collected by the photosensitive cleaner  614  to prepare for a next image forming again. Here, the collected transfer residual toner is conveyed by the conveying path  21  and then falls into the accommodating container  11  to be stored therein. 
     As illustrated in  FIG. 2 , the accommodating container  11  is disposed at the left back side of the apparatus body  60 A. The conveying path  21  is provided in the apparatus body  60 A to convey the transfer residual toner on the intermediate transfer belt  605  or the transfer residual toner remaining on the photosensitive drum  611 . These residual toners, as described above, are conveyed to the accommodating container  11  by the conveying path  21  and the toners collected in the accommodating container  11  are accumulated. 
       FIG. 3  is a sectional view illustrating a structure of the accommodating container  11 . The accommodating container  11  illustrated in  FIG. 3  includes a falling inlet  12  (receiving inlet) to which “powder” toner T falls to accommodate the falling toner T. A prism unit  13  is disposed at a position, which is closer to the right from the falling inlet  12  at a lateral face of the accommodating container  11 , to refract light emitted from a reflective sensor  17  (see  FIG. 4 ). That is, an introducing portion  23  of the prism unit  13 , which will be described below, is disposed outside the projecting region of the falling inlet  12  in the gravity direction thereof. 
       FIG. 4  is a sectional view as seen from a direction indicated by the arrow J in  FIG. 3 . In  FIG. 4 , however, the reflective sensor  17  is additionally provided compared to  FIG. 3 . As illustrated in  FIG. 4 , the prism unit  13  is installed to enter inside a lateral face of the accommodating container  11 . Accordingly, since the prism unit  13  is installed so as not to protrude from an outer peripheral of the accommodating container  11 , it does not become an obstacle when the accommodating container  11  is set in the apparatus body  60 A. 
     The reflective sensor  17  is disposed at the apparatus body  60 A side. Therefore, when the accommodating container  11  is disposed at a predetermined position of the apparatus body  60 A, the reflective sensor  17  is disposed at a position which is opposite to the prism unit  13 . The reflective sensor  17  may also be directly installed in the accommodating container  11 . However, since the accommodating container  11  is a regular replacement component, resulting in a damage of replacement property or an increase in a running cost, this embodiment is configured such that the reflective sensor  17  is retained in the apparatus body  60 A side. 
       FIG. 5  is a sectional view illustrating a structure of the powder amount detecting system  100 . The powder amount detecting system  100  illustrated in  FIG. 5  is provided with the prism unit  13  and the reflective sensor  17 . The prism unit  13  is detachably attachable to the accommodating container  11  and can easily be replaced and cleaned. The prism unit  13  is provided with a prism (prism portion)  14 , a covering member (casing portion)  22 , and an introducing member (guide portion)  23  (see  FIG. 6 ). In this embodiment, furthermore, the structure having the accommodating container  11  and the prism unit  13  is referred to as a “developer accommodating container”. 
     First, the reflective sensor  17  serving as a “detecting unit” includes a light emitting element  17   a  which emits light and a light receiving element  17   b  which receives the light emitted from the light emitting element  17   a . In addition, the reflective sensor  17  detects that the toner T within the accommodating container  11  is filled with a predetermined amount when a light path K from the light emitting element  17   a  to the light receiving element  17   b  is light-blocked by the toner T. Here, the reflective sensor  17  is disposed outside the accommodating container  11 . It will be described below where the toner T blocks out the light. 
     Next, the prism unit  13  includes a prism  14  inside the accommodating container  11 . The prism  14  is a member which is disposed inside the accommodating container  11  to define the light path K of the light. The prism  14  includes a first prism  14   a  (a first optical portion) and a second prism  14   b  (a second optical portion) having a reflective surface for reflecting the light in the middle of the light path K. The first prism  14   a  and the second prism  14   b  are arranged in a vertical direction. That is, the first prism  14   a  is disposed at an upper side and the second prism  14   b  is disposed at a lower side. The first prism  14   a  has a first reflective surface  15  which is an inclined surface in  FIG. 5  for reflecting the light and the second prism  14   b  has a second reflective surface  16  which is an inclined surface in  FIG. 5  for reflecting the light. 
     The first reflective surface  15 , the second reflective surface  16 , and the reflective sensor  17  are disposed so that the light emitted from the light emitting element  17   a  of the reflective sensor  17  is bent downward in a substantially vertical direction at the first reflective surface  15  and additionally bent to the light receiving element  17   b  of the reflective sensor  17  at the second reflective surface  16 . 
     A detecting region  20  (space portion) (accumulating space) which is an “accumulating space” is defined inside the accommodating container  11  and is a space that is defined to be capable of accumulating the toner T in the middle of the light path K. Particularly, the detecting region  20  is defined between the first prism  14   a  and the second prism  14   b . The toner T is introduced to the detecting region  20  and then is accumulated therein by the introducing member  23  (see  FIG. 6 ) which will be described later. It is configured to detect the presence of the toner T by closing the light path with the toner T which is flowed into the detecting region  20 . 
     The covering member  22  is disposed inside the accommodating container  11 . The covering member  22 , which is a “covering unit”, is a member that covers the prism  14  to cover the prism  14  from the toner T. For this reason, the covering member  22  is a member that covers the detecting region  20  at a region other than an introducing region of the introducing member  23 . 
       FIG. 6  is a perspective view illustrating a structure of the covering member  22  disposed in the accommodating container  11 . As illustrated in  FIG. 6 , the prism unit  13  includes the covering member  22  which covers the prism  14  (see  FIG. 7 ) in the prism unit  13 . By the covering member  22 , it is possible to prevent the toner T fallen from the falling inlet  12  from entering the detecting region  20  (see  FIG. 7 ) defined in the prism  14  without passing through the introducing member  23 . 
     In addition, the covering member  22  includes a first face  22   a  (inclined portion) which is inclined at a top face portion so as to descend to the falling inlet  12  side. That is, the first face  22   a  forms the top face of the covering member  22 . Further, the covering member  22  includes a front face portion  22   b  extending in a vertical direction, a second face  22   c  inclined so as to ascend, and a lateral face portion  22   d . Here, the lateral face portion  22   d  is a lateral face (a first lateral face) provided at the falling inlet  12  side of the accommodating container in the lateral face portion of the covering member  22 . In addition, the front face portion  22   b  and a lateral face opposite to the front face portion  22   b  are a pair of lateral faces (a second lateral face) which is adjacent to the lateral face portion  22   d  to form a lateral face of the covering member  22 . Further, a face opposite to the lateral face portion  22   d  in the lateral face portion of the covering member  22  is provided with the introducing member  23  (a third lateral face portion) to form a casing portion for covering a circumference of the prism  14 . In addition, a rib  22   e  is provided at an introducing inlet  23   a  (opening portion) side of the first face  22   a . Although the toner T is scattered inside the accommodating container  11 , the toner T is blocked out by the first face  22   a , the front face portion  22   b , the second face  22   c , the lateral face portion  22   d , and the rib  22   e , thereby not reaching the detecting region  20 . 
     Before the toner T enters the detecting region  20  of the prism  14 , the scattering toner descends and accumulates on the covering member  22  (blocking member). After a certain amount of the scattered and deposited toner T is accumulated, it is concerned that the toner T falls to the introducing member  23  from the introducing inlet  23   a  and flows into the detecting region. In this case, although the toner T is not accumulated to an assumed amount within the accommodating container  11 , fullness is early detected. In order to prevent these, the first face  22   a  is inclined to the falling inlet  12  side. The first face  22   a  prevents the scattering toner poured into the covering member  22  from being fallen to the introducing member  23 . In addition, the rib  22   e  further prevents from falling into the introducing member  23 . 
     Further, in the configuration of the embodiment, since the introducing member  23  is configured with an inclined face of a repose angle or more of the powder, the toner T reliably slides down on the introducing member  23 . It is configured to reliably introduce the toner T to the detecting region  20  by using a momentum of the sliding down. 
     However, in case where the toner T enters a circumference of the lowest point  25  (see  FIG. 7 ) of the introducing member  23  without passing through the introducing member  23 , since the toner T does not have the above-described momentum of the sliding down, it does not flow into the detecting region  20 . As a result, the toner T is gradually deposited on the fallen position (for example, the lowest point  25  of the introducing member  23 ) to become a wall, and thus the toner T flowing subsequently through the introducing member  23  does not reach the detecting region  20 . In this way, even when the accommodating container  11  becomes full, the toner T does not enter the detecting region  20 , and thus it is concerned that the light is not blocked out to generate a mechanical failure without detecting the fullness. 
     Therefore, the covering member  22  is configured such that an upper part  22   f  of the front face portion is equal to or higher than the uppermost point of the first face  22   a  or the rib  22   e  so as to prevent an inflow of the toner into the detecting region  20  from the front face portion  22   b . As a result, the toner T accumulated in the accommodating container  11  falls into the introducing member  23  beyond the rib  22   e  from the first face  22   a  rather than from the front face portion  22   b . As illustrated in  FIG. 3 , when a certain amount of the toner is accumulated by being deposited in a heap which has the falling inlet  12  at the top inside the accommodating container  11 , the skirts of the heap formed at the repose angle of the toner T is deposited up to the first face  22   a  and the rib  22   e . When the toner T is further deposited, the heap of the deposited toner swiftly collapses to collide with the wall  23   b  provided in the introducing member  23  and then slides down the introducing member  23 . As a result, the toner slides down the inclined face and can certainly reach the detecting region  20 . 
     As described above, the prism unit  13  includes the introducing member  23 . The introducing member  23  is disposed toward a lateral face of the accommodating container  11  rather than the falling inlet  12  (see  FIG. 6 ) and a member for introducing the toner T to the detecting region  20  inside the covering member  22 . In addition, the introducing member  23  may be referred to as a member for forming a part of the introducing inlet  23   a  which introduces the toner T with respect to the light path K (see  FIG. 5 ) formed by the prism  14 . 
       FIG. 7  is a sectional view illustrating a structure of the prism unit  13 . As described above, the prism  14  on the falling inlet  12  is covered by the covering member  22  to prevent the collected toner from entering the detecting region  20 . 
     Meanwhile, the prism unit  13  is provided with the introducing member  23  which is disposed toward the lateral face of the accommodating container  11  rather than the covering member  22  when viewed from the falling inlet  12  in the accommodating container  11  to introduce the toner T to the detecting region  20  when a predetermined amount of the toner T is deposited in the accommodating container  11 . By providing the introducing member  23 , it is possible to prevent the toner T from going on being deposited without entering the detecting region  20  due to a bridge caused by the toner T deposited in the vicinity of the detecting region. 
     As illustrated in  FIG. 7 , in the prism unit  13 , the introducing inlet  23   a  of the introducing member  23  as a portion thereof is open and other portions are covered by the covering member  22 . Therefore, in order to detect the light at the light path K of the prism  14 , a portion for accumulating the toner T introduced through the introducing member  23  is required inside the covering member  22 . 
     Here, the detecting region  20  is defined between the first prism  14   a  and the second prism  14   b , which are included in the prism  14 , to accumulate the toner T. Further, since the toner T accumulated in the detecting region  20  closes the light path K and thus the light does not come back to the light receiving element  17   b  of the reflective sensor  17 , it is detected that the toner T has reached a predetermined amount. 
     According to the configuration of the embodiment, the amount of the toner T within the accommodating container  11  is more reliably detected without being erroneously detected than ever before. Since the covering member  22  covers the detecting region  20 , a phenomenon in which the scattering toner T invades into the detecting region  20  from the regions other than the introducing region is suppressed. Since the toner T is introduced to the detecting region  20  through the introducing member  23 , the toner T accumulated in the accommodating container  11  is introduced to the detecting region  20 . 
     In this embodiment, since a top face (detecting region surface  26 ) of the second prism  14   b  included in the prism  14  also serves as a portion for accumulating the toner T, there is no need to separately provide a member to accumulate the toner T. 
     Moreover, in this embodiment, the light path K between the first prism  14   a  and the second prism  14   b  is set along the substantially vertical direction (see  FIG. 5 ). In these configurations, the light transmits the detecting region  20  when the toner T does not exist in the accommodating container  11 . When the toner T is introduced to the interior of the accommodating container  11 , as illustrated in  FIG. 9 , a thin layer of the toner T is formed on the detecting region surface  26  of the top face of the second prism  14   b , this layer of the toner T certainly closes the light path K, and thus it is detected that the toner T has reached a predetermined amount. 
     On the other hand, it is assumed that the prism  14  is disposed such that the light path K inside the detecting region  20  is formed along a substantially horizontal direction. This, for example, is equivalent to the configuration in which the prism  14  is rotated 90 degrees in a counterclockwise direction as illustrated in  FIG. 7 . That is, it is equivalent to a configuration in which the first prism  14   a  and the second prism  14   b  of the prism  14  are arranged in the horizontal direction. In these configurations, when the toner T is not accumulated over an entire region of the detecting region  20  between the first prism  14   a  and the second prism  14   b , the light path is not closed. For this reason, when the bridge arises in the accumulating portion, a gap occurs in a part, the light path is generated, and thus there is a concern about an erroneous detection. 
     Based on these, even though the amount of accumulated toner T is small, there is an advantage that the toner T is better detected when the light path K of the detecting region  20  is formed along the substantially vertical direction than when the light path K of the detecting region  20  is formed along the substantially horizontal direction. 
     Moreover, in this embodiment, the introducing member  23  is formed in a plate shape and is set larger than the repose angle of the toner T in an angle relative to a horizontal plane. When the introducing member  23  is set to such an inclined face, since the toner T is difficult to deposit on the introducing member  23 , the toner T is reliably introduced into the detecting region  20 . 
     Further, in this embodiment, a vertically upper side of the introducing member  23  is open (become an open space) in the interior of the accommodating container  11 . According to this configuration, the toner T to be deposited is bridged and thus a phenomenon which is not able to invade to the point of the introducing member  23  is suppressed. 
       FIG. 8  is a sectional view of the prism unit  13  illustrating a state at the time when the toner T is introduced. Moreover, this embodiment has described based on a system in which the introducing member  23  is provided at the opposite side to the falling inlet  12  of the accommodating container  11 , but may not be limited to this configuration. That is, as illustrated in  FIG. 7 , a gap  24  is formed between the introducing member  23  and the detecting region surface  26  which is formed in the second prism  14   b . In the case of this configuration, even when the toner T is introduced into the introducing member  23 , the toner T may fall down the covering member  22  without invading into the detecting region surface  26 . Moreover, a lower end of the gap  24  is adapted to a dead-end in  FIG. 7 , but an escaping hole (discharge outlet) for escaping the toner T is practically formed at the lower end of the gap  24 . Due to the above-described reasons, there is no need to dispose the introducing member  23  on the opposite side of the falling inlet  12 . 
       FIG. 9  is a sectional view of the prism unit  13  illustrating a state where the toner is introduced and reaches the detecting region surface  26 . As illustrated in  FIG. 9 , the toner T is accumulated between the second prism  14   b  and the introducing member  23  and reaches the surface of the detecting region surface  26 . 
       FIG. 10A  is a sectional view illustrating a structure of a powder amount detecting system  200  according to a modified example of the embodiment, and  FIG. 10B  is a perspective view of the powder amount detecting system  200 . Also, reference numerals used in  FIGS. 10A and 10B  having the same function as in the previous embodiment are designated by the same numerals and the description thereof will not be presented. In the above-described embodiment, the prism  14  is installed inside the accommodating container  11  and the reflective sensor  17  is disposed at the apparatus body  60 A side. However, it may not be limited to the configuration in which the above-described accommodating container  11  includes the light emitting element  17   a  and the light receiving element  17   b  and the light emitted from the light emitting element  17   a  is reflected by the reflective member which is separately provided. That is, as illustrated in  FIGS. 10A and 10B , even in the configuration provided with an optical sensor such as a photo interrupter  28  for directly self-receiving the light at the light receiving portion, while installation property or running cost deteriorates, the same effects may be obtained. Further, in this configuration, the photo interrupter  28  serving as “detecting unit” is made up of a light emitting element  28   a  and a light receiving element  28   b  facing each other and the detecting region  20  is defined between the light emitting element  28   a  and the light receiving element  28   b.    
     In addition, the powder amount detecting system  200  is installed inside the accommodating container  11 , even in this configuration, but it is configured such that the introducing member  23  is disposed at a side far from the falling inlet  12 . 
     According to the invention, it may reliably detect the amount of powders within the accommodating container without erroneous detection compared to the related art. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2012-154360, filed Jul. 10, 2012, which is hereby incorporated by reference herein in its entirety.