Patent Publication Number: US-10759626-B2

Title: Sheet safekeeping apparatus and image processing apparatus

Description:
FIELD 
     Embodiments described herein relate generally to a sheet safekeeping apparatus, an image processing apparatus, and methods associated therewith. 
     BACKGROUND 
     In a conventional image processing apparatus such as a printer, a sheet discharge section includes a plurality of sheet discharge trays. If a plurality of users uses such an image processing apparatus, discharged sheets on which images are recorded are sorted and accommodated. For example, a plurality of the sheet discharge trays is used as job separators. The job separator sorts the sheets by job to discharge them. A sheet safekeeping apparatus such as a job separator enables a user who succeeds in authentication to take out the sheets which are accommodated on the sheet discharge trays and on which images are formed. As a result, the sheet safekeeping apparatus ensures the confidentiality of the accommodated sheets on which images are formed. However, in order to take out sheets from a plurality of the sheet discharge trays, it is necessary to provide a driving source for opening and closing a removal port in each of a plurality of the sheet discharge trays. Therefore, there is a problem that the configuration of the sheet safekeeping apparatus becomes complicated. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view illustrating an image forming apparatus according to an embodiment; 
         FIG. 2  is a block diagram illustrating an example of functional components of the image forming apparatus according to the embodiment; 
         FIG. 3  is a front view illustrating a part of a sheet safekeeping apparatus according to the embodiment; 
         FIG. 4  is a schematic view of a conveyance unit and a cover displacement unit as viewed from an image forming apparatus main body side according to the embodiment; 
         FIG. 5  is a perspective view illustrating a housing section according to the embodiment; 
         FIG. 6  is a diagram for explaining an operation of the sheet safekeeping apparatus according to the embodiment; and 
         FIG. 7  is a diagram for explaining an operation of the sheet safekeeping apparatus according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with an embodiment, a sheet safekeeping apparatus comprises a multistage tray in which a plurality of housing sections for accommodating sheets is arranged side by side in a first direction, a removal port through which the accommodated sheet is taken out being formed in each of the plurality of the housing sections, and a cover for closing the removal port in an openable manner being provided in each of the plurality of the housing sections; a support section configured to support the multistage tray; a tray displacement unit configured to displace the multistage tray in the first direction with respect to the support section; a conveyance unit, arranged in the support section, configured to convey the sheet to a plurality of the housing sections; and a cover displacement unit, arranged in the support section, configured to displace the cover of one housing section determined by an operation of the tray displacement unit among the plurality of the housing sections to open the removal port. 
     Hereinafter, a sheet safekeeping apparatus and an image processing apparatus according to an embodiment are described with reference to the accompanying drawings. 
       FIG. 1  is a front view illustrating an image forming apparatus according to an embodiment.  FIG. 2  is a block diagram illustrating an example of functional components of the image forming apparatus according to the embodiment. 
     An image forming apparatus  1  comprises an image forming apparatus main body  2  and a sheet safekeeping apparatus  3 . The image forming apparatus main body  2  forms an image on a sheet-like medium such as a paper (hereinafter, collectively referred to as a “sheet S”). The image forming apparatus main body  2  discharges the sheet S on which an image is formed and sends it to the sheet safekeeping apparatus  3 . The sheet safekeeping apparatus  3  stores the sheet S discharged from the image forming apparatus main body  2 . 
     The image forming apparatus main body  2  comprises a control panel  11 , a scanner section  12 , a printer section  13 , a sheet feed section  14 , a sheet discharge section  15 , a user authentication section  16  and an image forming controller  17 . 
     The control panel  11  includes an operation section, a display section, and a panel controller. The operation section receives an operation from a user. For example, the operation section includes various keys and a touch panel. The display section displays various kinds of information. The panel controller controls reception of an operation from a user by the operation section and display on the display section. The panel controller is a control circuit having a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). For example, the control panel  11  receives an input relating to removal of the sheet S accommodated in the sheet safekeeping apparatus  3 . The image forming apparatus main body  2  sends information relating to the sheet S received by the control panel  11 , information relating to a type of post-processing, and the like to the sheet safekeeping apparatus  3 . 
     The scanner section  12  reads the image information of a copy object as intensity of light. The scanner section  12  sends the read image information to the printer section  13 . 
     The printer section  13  forms an output image (hereinafter referred to as a “toner image”) formed with a developer such as toner based on image information received from the scanner section  12  or an external device. The printer section  13  transfers the toner image onto a surface of the sheet S. The printer section  13  applies heat and pressure to the toner image on the surface of the sheet S to fix the toner image on the sheet S. The printer section  13  sends the sheet S on which the toner image is fixed to the sheet discharge section  15 . 
     The sheet feed section  14  supplies the sheets S one by one to the printer section  13  in accordance with a timing at which the printer section  13  forms a toner image. For example, the sheet feed section  14  includes a plurality of sheet feed cassettes. Each sheet feed cassette accommodates a sheet S of a preset size and type in advance. Each sheet feed cassette has a pickup roller. Each pickup roller takes out the sheets S one by one from each sheet feed cassette. Each pickup roller sends the sheet S taken out from each sheet feed cassette to the printer section  13 . 
     The sheet discharge section  15  sends the sheet S received from the printer section  13  to the sheet safekeeping apparatus  3 . 
     The user authentication section  16  authenticates a user. The user authentication section  16  authenticates the user based on read personal authentication information of the user. For example, the user authentication section  16  authenticates the user by comparing the personal authentication information of the user with authentication information stored in a database (not shown). The user authentication section  16  determines that the authentication of the user succeeds when the read personal authentication information matches the authentication information stored in a storage section (not shown). For example, the user authentication section  16  is a card reader or the like. The card reader reads the personal authentication information stored in an ID (identity) card etc. possessed by the user. 
     The image forming controller  17  controls the overall operation of the image forming apparatus main body  2 . The image forming controller  17  controls the control panel  11 , the scanner section  12 , the printer section  13 , the sheet feed section  14 , the sheet discharge section  15  and the user authentication section  16 . The image forming controller  17  is a control circuit having a CPU, a ROM, and a RAM. The image forming controller  17  executes a job designated by the user when the personal authentication succeeds in the user authentication section  16 . The image forming controller  17  sends the user information of a user who executes a job to a safekeeping controller  100  described later. 
     The sheet safekeeping apparatus  3  is adjacent to the image forming apparatus main body  2 . The sheet safekeeping apparatus  3  comprises a housing  20  (support section), a post-processing section  30 , a sheet safekeeping section  40  and the safekeeping controller  100 . 
     The housing  20  mainly contains the components of the post-processing section  30  therein. In the housing  20 , a sheet supply port  21  and a sheet discharge port  22  are formed. The sheet supply port  21  is formed to face the sheet discharge section  15  of the image forming apparatus main body  2 . The sheet S discharged from the image forming apparatus main body  2  is sent to the inside of the housing  20  through the sheet supply port  21 . The sheet discharge port  22  is formed at a position facing the opposite side of the sheet supply port  21  in the housing  20 . The sheet S sent from the post-processing section  30  to the sheet safekeeping section  40  passes through the sheet discharge port  22 . On the top of the housing  20 , a fixed tray  23  is formed. The sheet S is discharged to the fixed tray  23 . The fixed tray  23  supports the sheet S received from the post-processing section  30 . 
     The post-processing section  30  executes a post-processing designated through the control panel  11  on the sheet S conveyed from the image forming apparatus main body  2 . For example, the post-processing is a sorting processing, stapling processing, or the like. The post-processing section  30  includes a conveyance path  31 . The conveyance path  31  is provided in the housing  20 . The conveyance path guides the sheet S received from the image forming apparatus main body  2  to the sheet discharge port  22  or the fixed tray  23 . The conveyance path  31  includes a first conveyance path  31   a  and a second conveyance path  31   b . The first conveyance path  31   a  guides the sheet S from the sheet supply port  21  to the sheet discharge port  22 . The second conveyance path  31   b  branches from the first conveyance path  31   a  and directs to the fixed tray  23 . 
     The post-processing section  30  can perform the post-processing on the sheet S conveyed along the first conveyance path  31   a . The post-processing section  30  may not perform the post-processing on the sheet S conveyed along the first conveyance path  31   a . The post-processing section  30  does not perform the post-processing on the sheet S conveyed along the second conveyance path  31   b.    
       FIG. 3  is a front view illustrating a part of the sheet safekeeping apparatus according to the embodiment. 
     As shown in  FIG. 1  and  FIG. 3 , the sheet safekeeping section  40  stores the sheet S conveyed from the post-processing section  30 . The sheet safekeeping section  40  includes a conveyance unit  41 , a multistage tray  50 , a tray displacement unit  80  and a cover displacement unit  90 . 
       FIG. 4  is a schematic diagram of the conveyance unit and the cover displacement unit as viewed from the image forming apparatus main body side according to the embodiment. 
     As shown in  FIG. 3  and  FIG. 4 , the conveyance unit  41  conveys the sheet S to a later-described housing section  51  of the multistage tray  50 . The conveyance unit  41  is arranged in the housing  20 . The conveyance unit  41  includes a conveyance roller  42  and a conveyance motor  43 . 
     The conveyance roller  42  is arranged at a downstream end of the first conveyance path  31   a  of the post-processing section  30  in a sheet conveyance direction (refer to  FIG. 1 ). The conveyance roller  42  sends the sheet S received from the first conveyance path  31   a  to the housing section  51  when normally rotating. The conveyance roller  42  sends the sheet S to the housing section  51  via the sheet discharge port  22 . 
     The conveyance motor  43  drives the conveyance roller  42 . For example, the conveyance motor  43  is a DC (Direct Current) motor. The conveyance motor  43  can output rotational driving forces in two directions. The conveyance motor  43  enables the conveyance roller  42  to normally rotate by outputting a rotational driving force in a first direction. The conveyance motor  43  enables the conveyance roller  42  to reversely rotate by outputting a rotational driving force in a second direction. Here, in the horizontal direction, a direction in which the sheet S is discharged from the sheet discharge port  22  is defined as a forward direction, and an opposite side thereof is defined as a rearward direction. In the horizontal direction, a direction orthogonal to the front-rear direction is referred to as a left-right direction. In each figure, an arrow FR indicates the forward direction, and an arrow RR indicates the rearward direction. 
     As shown in  FIG. 1 , the multistage tray  50  is adjacent to the housing  20 . The multistage tray  50  faces the image forming apparatus main body  2  across the housing  20 . The multistage tray  50  is supported by the housing  20 . The multistage tray  50  includes a plurality of the housing sections  51  arranged side by side in a vertical direction (first direction). The plurality of the housing sections  51  has the same configuration except for the position thereof in the vertical direction. 
     As shown in  FIG. 3 , the housing section  51  accommodates the sheet S conveyed by the conveyance unit  41 . The housing section  51  can be switched between a storage state and a removal state. The storage state is a state in which the sheet S cannot be taken out from the housing section  51  as the cover  61  is closed. The removal state is a state in which the sheet S can be taken out from the housing section  51  as the cover  61  is open. In the following description of the configuration of the housing section  51 , the housing section in the storage state is described if there is no particular description. 
     A plurality of the housing sections  51  is arranged in plural stages. The housing section  51  is formed into a box shape, in which an entry port  52  through which the sheet S is carried and a removal port  53  through which the sheet S is taken out are formed. The entry port  52  faces the sheet discharge port  22  of the housing  20 . 
       FIG. 5  is a perspective view illustrating the housing section according to the embodiment. 
     As shown in  FIG. 5 , the housing section  51  includes a housing section main body  55 , a cover  61 , a locking device  66 , a rear wall  68  (sheet pushing wall), a cover pushing member  71 , a cover support section  73  and a first energization member  75 . 
     The housing section main body  55  is formed into a rectangular parallelepiped shape, which opens forward and rearward. An opening towards the front side of the housing section main body  55  is the removal port  53  of the housing section  51 . The housing section main body  55  includes a bottom wall  56 , a top wall  57 , and a pair of side walls  58 . In  FIG. 5 , only one side wall  58  is shown. 
     The bottom wall  56  constitutes the bottom of the housing section main body  55 . A front end edge  56   a  and a rear end edge  56   b  of the bottom wall  56  extend in the left-right direction, respectively. The bottom wall  56  extends slightly upwards as it directs forward from the rear end edge  56   b . On the bottom wall  56 , a sheet S accommodated in the housing section  51  is placed. In the bottom wall  56 , a plurality of slits  56   c  extending forward from the rear end edge  56   b  is formed. The plurality of slits  56   c  extends in parallel with each other. In other words, the bottom wall  56  includes a plurality of sinking comb  56   d  extending rearward. 
     The top wall  57  constitutes an upper portion of the housing section main body  55 . The top wall  57  is parallel to the bottom wall  56 . 
     The pair of side walls  58  constitutes portions on both sides in the left-right direction of the housing section main body  55 . The pair of side walls  58  is arranged with a interval therebetween larger than the accommodated sheet S. The pair of side walls  58  extends in the vertical direction, respectively. The pair of side walls  58  connects the bottom wall  56  and the top wall, respectively. 
     The cover  61  closes the removal port  53  of the housing section  51  in an openable manner. The cover  61  is formed in a plate shape. The cover  61  is formed in a rectangular shape extending in both the vertical direction and the left-right direction when viewed from the forward direction. The upper end edge  61   a  of the cover  61  is arranged in the vicinity of the front end of the top wall  57 . The lower end edge  61   b  of the cover  61  is arranged in the vicinity of the front end of the bottom wall  56 . The cover  61  is provided to be capable of being displaced with respect to the housing section main body  55 . The lower end of the cover  61  is connected to the front end of the bottom wall  56 . The cover  61  is attached to the bottom wall  56  via a hinge  63 . The cover  61  is rotatable around an axis extending in the left-right direction with respect to the bottom wall  56 . The cover  61  rotates in such a manner that the upper end thereof circulates around the lower end thereof. The housing section  51  shifts from the storage state to the removal state when the upper end of the cover  61  is displaced forward. 
     As shown in  FIG. 3 , a spring  64  is attached to the hinge  63 . For example, the spring  64  is a torsion coil spring. The spring  64  applies an energization force to the cover  61  in a direction of closing the cover  61 . In other words, the spring  64  applies an energization force to the cover  61  via the hinge  63  so that the upper end of the cover  61  is displaced rearward. 
     As shown in  FIG. 5 , the locking device  66  regulates the rotation of the cover  61  for closing the removal port  53  of the housing section  51 . For example, the locking device  66  is attached to the top wall  57 . The operation of the locking device  66  is controlled by the safekeeping controller  100 . 
     The rear wall  68  faces the removal port  53  across the accommodated sheet S. The rear wall  68  closes a part of the opening at rear side of the housing section main body  55 . The rear wall  68  is formed in a plate shape. The rear wall  68  is formed in a rectangular shape extending in both the vertical direction and the left-right direction as viewed from the rear side. The rear wall  68  extends perpendicularly to the bottom wall  56 . The upper end edge  68   a  of the rear wall  68  is arranged below the top wall  57  in the vicinity of the rear end of the top wall  57 . Thereby, a gap is formed between the top wall  57  and the rear wall  68 . The gap between the top wall  57  and the rear wall  68  is the entry port  52  of the housing section  51 . 
     An insertion portion  69  is formed in the rear wall  68 . For example, the insertion portion  69  is a plurality of through holes. The sinking comb  56   d  of the bottom wall  56  is inserted through the insertion portion  69  from the front side. As a result, the rear wall  68  can move forward with respect to the bottom wall  56  in a state of intersecting with the bottom wall  56  when viewed from the left-right direction. 
     The cover pushing member  71  extends forward from the rear wall  68 . For example, the cover pushing member  71  is formed in a bar shape. The cover pushing member  71  is arranged above the bottom wall  56 . The cover pushing member  71  is arranged between the sheet S placed on the bottom wall  56  and the side wall  58 . The cover pushing member  71  extends substantially in parallel with the bottom wall  56 . The cover pushing member  71  extends from the rear wall  68  to the rear side of the cover  61  and to the vicinity of the cover  61 . 
     The cover support section  73  extends forward from the lower end of the rear wall  68 . For example, the cover support section  73  is formed in a plate shape. The cover support section  73  extends along the lower surface of the bottom wall  56 . The cover support section  73  extends from the rear wall  68  to the vicinity of the front end of the bottom wall  56 . 
     The first energization member  75  energizes the rear wall  68  rearward with respect to the housing section main body  55 . The first energization member  75  directly or indirectly energizes the rear wall  68 . For example, the first energization member  75  may be connected to the housing section main body  55  and the rear wall  68 . For example, the first energization member  75  may be arranged inside the housing section  51 . The first energization member  75  is arranged at a position where it does not interfere with the operation of the sheet S accommodated in the housing section  51 . 
     As shown in  FIG. 1 , the tray displacement unit  80  displaces the multistage tray  50  in the vertical direction with respect to the housing  20 . For example, the tray displacement unit  80  is arranged in the housing  20 . The tray displacement unit  80  includes a guide mechanism, a motor, and a power transmission section. The guide mechanism guides the multistage tray  50  in the vertical direction. The motor supplies a force to enable the multistage tray  50  to rise or fall. The power transmission section transmits power from the motor to the multistage tray  50 . For example, the power transmission section is constituted by a pulley, a belt or the like. 
     As shown in  FIG. 3 , the cover displacement unit  90  is arranged in the housing  20 . The cover displacement unit  90  displaces the cover  61  of one housing section  51  determined by the operation of the tray displacement unit  80  among the plurality of the housing sections  51  of the multistage tray  50 . The cover displacement unit  90  displaces the cover  61  of the housing section  51  at a predetermined position in the vertical direction among a plurality of the housing sections  51 . For example, the cover displacement unit  90  displaces the cover  61  of the housing section  51  at a position where the conveyance unit  41  can convey the sheet S. The cover displacement unit  90  pushes the rear wall  68  of the housing section  51  forward. 
     As shown in  FIG. 3  and  FIG. 4 , the cover displacement unit  90  includes a rack  91 , a pinion  92 , a one-way clutch  93  and a second energization member  94 . The cover displacement unit  90  includes a conveyance motor  43  of the conveyance unit  41 . 
     As shown in  FIG. 3 , the rack  91  is provided to be movable forward and rearward. The rack  91  is bi-directionally displaced between a retraction position and an operating position in front of the retraction position. The retraction position is a position where the rack  91  retracts rearward from the multistage tray  50  as shown in  FIG. 3 . The retraction position is a position where the rack  91  does not contact with the multistage tray  50 . The retraction position is a position where the rack  91  does not interfere with the displacement of the multistage tray  50  in the vertical direction. The rack  91  protrudes from the housing  20  towards the housing section  51  by moving forward from the retraction position. For example, the rack  91  protrudes from the housing  20  through the sheet discharge port  22 . 
     The pinion  92  meshes with the rack  91 . The pinion  92  rotates in a third direction to move the rack  91  forward. The pinion  92  is rotated by a rotational driving force from the conveyance motor  43  (refer to  FIG. 4 ) of the conveyance unit  41 . The pinion  92  rotates in the third direction by the rotational driving force from the conveyance motor  43  in the second direction. 
     As shown in  FIG. 4 , the rotational driving force from the conveyance motor  43  is transmitted to the one-way clutch  93 . The one-way clutch  93  is arranged on a power transmission path from the conveyance motor  43  to the pinion  92 . The one-way clutch  93  is connected to the conveyance motor  43  and the pinion  92  via a gear, a rotating shaft, a belt, and the like. The one-way clutch  93  cuts off the transmission of the rotational driving force from the conveyance motor  43  to the pinion  92  or transmits the rotational driving force to the pinion  92 . The one-way clutch  93  transmits the rotational driving force from the conveyance motor  43  in the second direction to the pinion  92 . The one-way clutch  93  cuts off the transmission of the rotational driving force from the conveyance motor  43  in the first direction to the pinion  92 . As a result, the pinion  92  and the rack  91  do not operate when the conveyance roller  42  of the conveyance unit  41  normally rotates. 
     As shown in  FIG. 3 , the second energization member  94  energizes the rack  91  rearward. The second energization member  94  displaces the rack  91  towards the retraction position if the transmission of the power from the conveyance motor  43  to the rack  91  is stopped. 
     As shown in  FIG. 2 , the safekeeping controller  100  controls the overall operation of the sheet safekeeping apparatus  3 . The safekeeping controller  100  controls the post-processing section  30  and the sheet safekeeping section  40 . The safekeeping controller  100  includes a CPU  101  and a storage device  102  (storage section). 
     The storage device  102  stores a data table for storing identification information of the housing sections  51  of the multistage tray  50 . In the data table, the identification information of each housing section  51  and identification information of a user are associated with each other. The storage device  102  stores information relating to the presence or absence of the sheet S accommodated in each housing section  51 . For example, if the sheet S is accommodated in the empty housing section  51 , the storage device  102  stores the identification information of the housing section  51  in which the sheet S is accommodated and the identification information of the user who executes a job. 
     Next, the operation of the sheet safekeeping apparatus  3  is described with reference to  FIG. 3 ,  FIG. 6  and  FIG. 7 . 
       FIG. 6  and  FIG. 7  are diagrams for explaining the operation of the sheet safekeeping apparatus according to the embodiment, and are front views illustrating a part of the sheet safekeeping apparatus in the embodiment. 
     As shown in  FIG. 3  and  FIG. 6 , the cover displacement unit  90  moves the rack  91  forward by a predetermined distance from the retraction position to enable the rack  91  to contact with the rear wall  68  from the rear side. The cover displacement unit  90  further moves the rack  91  forward to move the rear wall  68 , the cover pushing member  71  and the cover support section forward with respect to the bottom wall  56 . 
     If the rear wall  68  moves forward with respect to the bottom wall  56 , the rear wall  68  contacts with the sheet S placed on the bottom wall  56  from the rear side. As a result, the rear wall  68  pushes the sheet S towards the removal port  53  by the operation of the cover displacement unit  90 . Since the rear wall  68  intersects with the bottom wall  56  when viewed from the left-right direction, the lowermost sheet S directly placed on the bottom wall  56  can also be reliably pushed. 
     If the cover pushing member  71  moves forward with respect to the bottom wall  56 , the cover pushing member  71  contacts with the cover  61  from the rear side. The cover pushing member  71  further moves forward with respect to the bottom wall  56  to push the cover  61  forward. Then, the upper end of the cover  61  rotates forward against the energization force from the spring  64 . As a result, the cover pushing member  71  can push the cover  61  with the cover displacement unit  90  to open the removal port  53 . 
     The cover support section  73  protrudes forward from the bottom wall  56  as it moves forward with respect to the bottom wall  56 . If the cover support section  73  protrudes forward from the bottom wall  56 , the cover support section  73  can contact with the cover  61  rotatably connected to the front end of the bottom wall  56  from below. Thus, the cover support section  73  regulates a rotation range of the cover  61 . For example, the cover support section  73  prevents the cover  61  from being excessively opened due to the weight of the sheet S when the cover  61  is opened and the sheet S is pushed by the rear wall  68  and is located above the cover  61 . 
     The cover displacement unit  90  finishes the operation of opening the removal port  53  by enabling the rack  91  to reach the operating position shown in  FIG. 6 . 
     As shown in  FIG. 7 , the cover displacement unit  90  stops the transmission of the driving force from the conveyance motor  43  to the rack  91  when the removal port  53  is closed. The rack  91  is then pulled rearward by the second energization member  94  to retract from the operating position towards the retraction position. 
     The rear wall  68  moves rearward by the energization force of the first energization member  75  when the rack  91  retracts from the operating position. The cover pushing member  71  and the cover support section  73  moves rearward in conjunction with the rear wall  68 . If the cover pushing member  71  moves rearward, the cover  61  rotates in such a manner that the upper end moves upward and rearward by the energization force of the spring  64 . As a result, the cover  61  closes the removal port  53  of the housing section  51 . 
     If the sheet S is placed on the bottom wall  56  when the rear wall  68  moves rearward, the sheet S moves rearward together with the rear wall  68  due to the inclination of the bottom wall  56 . As a result, the sheet S placed on the bottom wall  56  does not hinder the operation of closing the cover  61 . 
     Next, the control by the safekeeping controller  100  is described. 
     When the sheet S is conveyed from the image forming apparatus main body  2 , the safekeeping controller  100  determines a conveyance destination of the sheet S according to the job. For example, the safekeeping controller  100  conveys the sheet S to the fixed tray  23  if there is no identification information of the user associated with the job. For example, the safekeeping controller  100  conveys the sheet S to the sheet discharge port  22  if the identification information of the user is associated with the job. 
     The safekeeping controller  100  controls the sheet safekeeping section  40  in response to the user who executes the job if the conveyance destination of the sheet S is determined as the sheet discharge port  22 . The safekeeping controller  100  determines whether or not the identification information of the user who executes the job is included in the data table. 
     If the identification information of the user who executes the job is included in the data table, the safekeeping controller  100  acquires the associated identification information of the housing section  51 . The safekeeping controller  100  controls the tray displacement unit  80  so that the entry port  52  of the target housing section  51  faces the sheet discharge port  22 , based on the acquired identification information of the housing section  51 . Specifically, the safekeeping controller  100  displaces the multistage tray  50  with the tray displacement unit  80  so that the sheet S can be conveyed to the housing section  51  corresponding to the user who executes the job. 
     If the identification information of the user who executes the job is not included in the data table, the safekeeping controller  100  accommodates the sheet S in the empty housing section  51 . Specifically, the safekeeping controller  100  controls the tray displacement unit  80  so that the entry port  52  of the empty housing section  51  faces the sheet discharge port  22 . At this time, the safekeeping controller  100  stores the identification information of the user who executes the job in the storage device  102  in association with the identification information of the housing section  51 . 
     If the operation of the tray displacement unit  80  is terminated, the safekeeping controller  100  controls the conveyance unit  41  to send a sheet S from the sheet discharge port  22 . As a result, the sheet S is accommodated in the housing section  51 . 
     The safekeeping controller  100  determines the housing section  51  whose removal port  53  is to be opened in response to the operation by the user on the control panel  11 . The safekeeping controller  100  controls the sheet safekeeping section  40  when receiving an instruction to take out the sheet from a user authenticated by the user authentication section  16 . The safekeeping controller  100  refers to the data table to acquire the identification information of the housing section  51  corresponding to the user who issues the instruction to take out the sheet. The safekeeping controller  100  controls the tray displacement unit  80  so that the rear wall  68  of the target housing section  51  faces the front end of the rack  91  based on the acquired identification information of the housing section  51 . The safekeeping controller  100  controls the locking device  66  of the target housing section  51  to unlock the cover  61 . The safekeeping controller  100  controls the cover displacement unit  90  to move the rack  91  forward when the operation of the locking device  66  is completed. As a result, the removal port  53  of the housing section  51  corresponding to the user who issues the instruction to take out the sheet is opened. 
     The safekeeping controller  100  controls the sheet safekeeping section  40  so that the cover  61  of the housing section  51  can be opened for a predetermined period of time. Specifically, the safekeeping controller  100  controls the cover displacement unit  90  so that the cover  61  closes the removal port  53  after a predetermined period of time has elapsed since the removal port  53  of the housing section  51  is opened. Specifically, the safekeeping controller  100  controls the cover displacement unit  90  to retract the rack  91  after a predetermined period of time has elapsed since the removal port  53  of the housing section  51  is opened. The safekeeping controller  100  controls the locking device  66  to lock the cover  61  when the rack  91  retracts and the removal port  53  is closed. Thus, the sheet S in the housing section  51  cannot be taken out. 
     Hereinafter, the effects of the present embodiment are described. 
     The sheet safekeeping apparatus  3  of the present embodiment comprises the cover displacement unit  90 . The cover displacement unit  90  displaces the cover  61  of one housing section  51  among the plurality of the housing sections  51  of the multistage tray  50  to open the removal port  53 . The one housing section  51  is determined by the operation of the tray displacement unit  80 . According to such a configuration, the cover  61  can be opened and closed by the cover displacement unit  90  without arranging a driving source for displacing the cover  61  to each of the plurality of the housing sections  51 . Therefore, it is possible to prevent the configuration of the sheet safekeeping apparatus  3  from becoming complicated. 
     The cover pushing member  71  is provided for each of the plurality of the housing sections  51 . The cover pushing member  71  pushes the cover  61  by the operation of the cover displacement unit  90  to open the removal port  53 . According to such a configuration, the cover displacement unit  90  can displace the cover  61  without directly contacting with the cover  61 . As a result, the cover displacement unit  90  can displace the cover  61  by an operation thereof at a relatively short distance from a position where it does not interfere with the displacement of the multistage tray  50  by the tray displacement unit  80 . Therefore, it is possible to prevent the cover displacement unit  90  from becoming large. 
     The rear wall  68  is provided for each of the plurality of the housing sections  51 . The rear wall  68  faces the removal port  53  across the sheet S accommodated in the housing section  51 . The rear wall  68  pushes the sheet S towards the removal port  53  by the operation of the cover displacement unit  90 . According to such a configuration, the rear wall  68  can move the sheet S towards the removal port  53  while aligning the rear end of the sheet S. As a result, the sheet safekeeping apparatus  3  can discharge the sheet S from the removal port  53  with the rear end of the sheet S aligned. Therefore, it is possible to discharge the bundle of sheets S with the bundle of sheets S accommodated in the housing section  51  aligned. 
     The bottom wall  56  on which the accommodated sheet S is placed is provided for each of the plurality of the housing sections  51 . The rear wall  68  intersects with the bottom wall  56  when viewed from the left-right direction. According to such a configuration, no gap is formed between the upper surface of the bottom wall  56  and the rear wall  68  when viewed from the left-right direction. Therefore, the rear wall  68  can reliably push the lowermost sheet S among the sheets S placed on the bottom wall  56 . Therefore, the sheet safekeeping apparatus  3  can reliably discharge all of the accommodated sheets S from the removal port  53 . 
     The cover displacement unit  90  includes the rack  91  and the pinion  92 . The rack  91  is bi-directionally displaced between the retraction position where the rack  91  retracts from the multistage tray  50  and the operating position where the rack  91  protrudes from the housing  20  towards the housing section  51 . The pinion  92  meshes with the rack  91  to displace the rack  91 . According to such a configuration, the rack  91  does not interfere with the displacement of the multistage tray  50  at the retraction position. The rack  91  can contact with the housing section  51  at the operating position to displace the cover  61 . Thus, the cover displacement unit  90  can open the removal port  53  by displacing the cover  61  of one housing section  51  determined by the operation of the tray displacement unit  80 . 
     The cover displacement unit  90  includes the conveyance motor  43  of the conveyance unit  41 . The cover displacement unit  90  operates by the driving force from the conveyance motor  43 . According to such a configuration, the number of the driving sources of the whole sheet safekeeping apparatus  3  can be reduced as compared with the case in which the cover displacement unit has a drive source separated from that of the conveyance motor  43 . Therefore, it is possible to prevent the configuration of the sheet safekeeping apparatus  3  from being complicated. 
     The cover displacement unit  90  includes the one-way clutch  93  to which the driving force from the conveyance motor  43  is transmitted. The one-way clutch  93  cuts off the transmission of the driving force from the conveyance motor  43  when the sheet S is sent to one housing section  51  by the conveyance roller  42  of the conveyance unit  41 . According to such a configuration, the cover displacement unit  90  does not displace the cover  61  when the conveyance unit  41  conveys the sheet S to the housing section  51 . Therefore, in the configuration in which the conveyance unit  41  and the cover displacement unit  90  use the driving source together, the conveyance unit  41  can operate independently from the cover displacement unit  90 . 
     A plurality of the housing sections  51  is provided side by side in the vertical direction. According to such a configuration, an installation area of the multistage tray  50  can be reduced when compared with the case in which a plurality of the housing sections is arranged in a direction intersecting with the vertical direction. Accordingly, it is possible to provide the sheet safekeeping apparatus  3  with installation area thereof reduced. 
     The safekeeping controller  100  controls the cover displacement unit  90  so that the cover  61  closes the removal port  53  after a predetermined period of time has elapsed since the removal port  53  of the housing section  51  is opened. According to such a configuration, it is possible to prevent the removal port  53  of the housing section  51  from being kept open. Therefore, it is possible to provide the sheet safekeeping apparatus  3  suitable for accommodating confidential documents. 
     The safekeeping controller  100  opens the removal port of one housing section  51  corresponding to the authenticated user when the user is authenticated by the user authentication section  16 . According to such a configuration, only the authenticated user can take out the sheet S from the housing section  51 . In other words, it is possible to prevent an unauthenticated user from taking out the sheet S from the housing section  51 . Therefore, it is possible to provide the sheet safekeeping apparatus  3  suitable for accommodating confidential documents. 
     The safekeeping controller  100  comprises the storage device  102 . The storage device  102  stores the information relating to the presence or absence of the sheets S accommodated in the plurality of the housing sections  51 . According to such a configuration, the sheet safekeeping apparatus  3  can accommodate the sheet S in the housing section  51  according to the presence or absence of the sheets S accommodated in the plurality of the housing sections  51 . 
     The storage device  102  stores the identification information of the user who executes the job at the time of accommodating the sheets S in the plurality of the housing section  51 . According to such a configuration, the sheet safekeeping apparatus  3  can allocate the plurality of the housing sections  51  for each user. Therefore, at the time of accommodating the sheet S, the sheet safekeeping apparatus  3  can accommodate the sheet S in the housing section  51  corresponding to the user who executes the job. 
     The image forming apparatus  1  comprises the sheet safekeeping apparatus  3  and the image forming apparatus main body  2 . According to such a configuration, the image forming apparatus  1  can accommodate the sheets S in the plurality of the housing sections  51 . 
     In the above embodiment, the image forming apparatus  1  having the printer section  13  is taken as an example of the image processing apparatus provided with the sheet safekeeping apparatus  3 , but it is not limited thereto. The image processing apparatus provided with the sheet safekeeping apparatus  3  may be a decoloring device that performs a decoloring processing on a sheet on which an image is formed. 
     In the above embodiment, the tray displacement unit  80  is arranged in the housing  20 , but it is not limited thereto. For example, the tray displacement unit  80  may be arranged in the multistage tray. 
     In the above embodiment, the tray displacement unit  90  includes the power transmission section constituted by the pulley, the belt, and the like, but it is not limited thereto. For example, the power transmission section may be a rack and pinion mechanism, a ball screw, or the like. 
     In the above-described embodiment, the removal port  53  of the housing section  51  is opened forward, but it is not limited thereto. For example, the removal port may be opened in either the left direction or the right direction. 
     In the above embodiment, the cover  61  of the housing section  51  is connected to the bottom wall  56 , but it is not limited thereto. For example, the cover of the housing section may be connected to the top wall  57  or the side wall  58 . For example, the cover of the housing section may be connected to the cover pushing member or the cover support section to be capable of moving forward and rearward in conjunction with the rear wall  68 . 
     In the above embodiment, the cover displacement unit  90  includes the rack  91  and the pinion  92 , but it is not limited thereto. For example, the cover displacement unit may move a member corresponding to the rack  91  of the embodiment forward and rearward with a solenoid and an energization member. 
     In the above-described embodiment, the plurality of the housing sections  51  is provided side by side in the vertical direction, but it is not limited thereto. For example, the plurality of the housing sections may be provided side by side in the horizontal direction. As a result, it is possible to reduce the height of the multistage tray. 
     In the above embodiment, the user authentication section  16  is included in the image forming apparatus main body  2  and is shared by the image forming apparatus main body  2  and the sheet safekeeping apparatus  3 , but it is not limited thereto. The user authentication section may be provided in the sheet safekeeping apparatus  3  alone. 
     In the above embodiment, the cover displacement unit  90  is capable of displacing the cover  61  of the housing section  51  at a position where the conveyance unit  41  can convey the sheet S. However, it is not limited thereto. For example, the cover displacement unit  90  may be capable of displacing the cover  61  of the housing section  51  at a height position different from the position at which the conveyance unit  41  can convey the sheet S. 
     In the above embodiment, each of the housing sections  51  may be provided with a sensor for determining whether or not the sheet S is accommodated. Then, the safekeeping controller  100  may control the sheet safekeeping section  40  based on the detection results of the sensors. 
     According to at least one embodiment described above, the sheet safekeeping apparatus comprises the cover displacement unit. The cover displacement unit opens the removal port by displacing the cover of one housing section among the plurality of the housing sections of the multistage tray. The one housing section is determined by the operation of the tray displacement unit. Thereby, the cover can be opened and closed by the cover displacement unit without arranging a driving source for displacing the cover in each of the plurality of the housing sections. Therefore, it is possible to prevent the configuration of the sheet safekeeping apparatus from being complicated. 
     While certain embodiments have been described these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms: furthermore various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and there equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.