Sheet stacking apparatus and image forming apparatus

Abstract

A sheet stacking apparatus includes a plurality of storages, a plurality of conveyance portions provided above sheets stored in the storages, respectively, to convey the sheets, and a main body frame holding the storages and having a plurality of opening portions through which the storages are movable between a closed position in which the sheets are conveyed and a pullout position in which the sheets are stacked. The storages include a plurality of exterior covers, respectively, each exterior cover being larger than a corresponding opening portion so as to cover the corresponding opening portion. The storages are arranged so that the plurality of exterior covers are aligned in a vertical direction. A conveyance portion, which conveys the sheets stored in a lower storage of the storages, overlaps an exterior cover of a storage one above the lower storage in the vertical direction when viewed in a horizontal direction.

What is claimed is: 
     
         1 . A sheet stacking apparatus, comprising:
 a plurality of storages configured to store sheets;   a plurality of conveyance portions, which are provided above the sheets stored in the plurality of storages, respectively, and are configured to convey the sheets in a conveyance direction; and   a main body frame having a plurality of opening portions, the main body frame being configured to hold the plurality of storages so that each of the storages is movable through a corresponding one of the plurality of opening portions between a closed position in which the sheets are allowed to be conveyed and a pullout position in which the sheets are allowed to be stacked,   wherein the plurality of storages include a plurality of exterior covers, respectively, each of the exterior covers being larger than a corresponding one of the plurality of opening portions so as to cover the corresponding one of the plurality of opening portions,   wherein the plurality of storages are arranged so that the plurality of exterior covers are aligned in a vertical direction, and   wherein a conveyance portion, which conveys the sheets stored in a lower storage of the plurality of storages, overlaps an exterior cover of a storage one above the lower storage in the vertical direction when viewed in a horizontal direction.   
     
     
         2 . The sheet stacking apparatus according to  claim 1 , wherein each storage of the plurality of storages includes a second positioning member configured to be engaged with a first positioning member, which is provided to the main body frame, so as to position the storage with respect to the main body frame. 
     
     
         3 . The sheet stacking apparatus according to  claim 1 ,
 wherein the main body frame has a plurality of first sealing surfaces,   wherein the plurality of storages have a plurality of second sealing surfaces arranged so as to be opposed to the plurality of first sealing surfaces, respectively, and   wherein the sheet stacking apparatus includes a plurality of seal members arranged between the plurality of first sealing surfaces and the plurality of second sealing surfaces, respectively.   
     
     
         4 . The sheet stacking apparatus according to  claim 3 ,
 wherein the plurality of seal members are attached to one of the plurality of first sealing surfaces and the plurality of second sealing surfaces, respectively, and   wherein, when the plurality of storages are located in the closed positions, the plurality of seal members are in contact with the other of the plurality of first sealing surfaces and the plurality of second sealing surfaces.   
     
     
         5 . The sheet stacking apparatus according to  claim 4 , wherein the conveyance portion provided to the lower storage of the plurality of storages overlaps a seal member of the plurality of seal members, which is configured to hermetically seal the storage one above the lower storage, in the vertical direction when viewed in the horizontal direction. 
     
     
         6 . The sheet stacking apparatus according to  claim 3 , wherein the plurality of seal members have elasticity. 
     
     
         7 . The sheet stacking apparatus according to  claim 1 ,
 wherein at least a part of the conveyance portion provided to the lower storage is arranged so as to project upward beyond a top surface of an exterior cover of the lower storage, and   wherein the storage one above the lower storage is provided with a space into which at least the part of the conveyance portion is inserted.   
     
     
         8 . The sheet stacking apparatus according to  claim 1 , wherein each storage of the plurality of storages includes a lower plate provided with a protruded portion and an upper plate provided with a protruded portion into which at least a part of the conveyance portion is inserted. 
     
     
         9 . A sheet stacking apparatus comprising:
 a first storage configured to store sheets;   a first conveyance portion configured to convey the sheets stored in the first storage;   a second storage configured to store sheets above the sheets stored in the first storage;   a second conveyance portion configured to convey the sheets stored in the second storage; and   a main body frame having a first opening portion and a second opening portion, the main body frame being configured to hold the first storage so that the first storage is movable through the first opening portion between a closed position in which the sheets are allowed to be conveyed and a pullout position in which the sheets are allowed to be stacked, and the main body frame being configured to hold the second storage so that the second storage is movable through the second opening portion between a closed position in which the sheets are allowed to be conveyed and a pullout position in which the sheets are allowed to be stacked,   wherein the second storage is provided with an exterior cover being larger than the second opening portion so as to cover the second opening portion when the second storage is located in the closed position,   wherein the first conveyance portion includes a rotary member configured to feed a sheet when being rotated while being in contact with the sheet stored in the first storage, and   wherein the rotary member overlaps the exterior cover of the second storage in a vertical direction when viewed in a horizontal direction.   
     
     
         10 . The sheet stacking apparatus according to  claim 9 , wherein each of the first storage and the second storage includes a second positioning member configured to be engaged with a first positioning member, which is provided to the main body frame, so as to position a corresponding one of the first storage and the second storage with respect to the main body frame. 
     
     
         11 . The sheet stacking apparatus according to  claim 9 ,
 wherein the main body frame has a first sealing surface,   wherein the second storage has a second sealing surface arranged so as to be opposed to the first sealing surface, and   wherein the sheet stacking apparatus includes a seal member arranged between the first sealing surface and the second sealing surface.   
     
     
         12 . The sheet stacking apparatus according to  claim 11 ,
 wherein the seal member is attached to one of the first sealing surface and the second sealing surface, and   wherein, when the second storage is located in the closed position, the seal member is in contact with the other of the first sealing surface and the second sealing surface.   
     
     
         13 . The sheet stacking apparatus according to  claim 12 , wherein the rotary member of the first conveyance portion overlaps the seal member in the vertical direction when viewed in the horizontal direction. 
     
     
         14 . The sheet stacking apparatus according to  claim 11 , wherein the seal member has elasticity. 
     
     
         15 . The sheet stacking apparatus according to  claim 9 ,
 wherein at least a part of the first conveyance portion provided to the first storage projects upward beyond a top surface of an exterior cover of the first storage, and   wherein the second storage is provided with a space into which at least the part of the first conveyance portion is inserted.   
     
     
         16 . The sheet stacking apparatus according to  claim 9 , wherein the second storage includes a lower plate provided with a protruded portion projecting upward. 
     
     
         17 . An image forming apparatus comprising:
 a sheet stacking apparatus; and   an image forming portion configured to form an image on a sheet stacked in the sheet stacking apparatus, the sheet stacking apparatus including:
 a plurality of storages configured to store sheets; 
 a plurality of conveyance portions, which are provided above the sheets stored in the plurality of storages, respectively, and are configured to convey the sheets in a conveyance direction; and 
 a main body frame having a plurality of opening portions, which is configured to hold the plurality of storages so that each of the plurality of storages is movable through a corresponding one of the plurality of opening portions between a closed position in which the sheets are allowed to be conveyed and a pullout position in which the sheets are allowed to be stacked, 
 wherein the plurality of storages include a plurality of exterior covers, respectively, each of the exterior covers being larger than a corresponding one of the plurality of opening portions so as to cover the corresponding one of the plurality of opening portions, 
 wherein the plurality of storages are arranged so that the plurality of exterior covers are aligned in a vertical direction, and 
 wherein a conveyance portions, which conveys the sheets stored in a lower storage of the plurality of storages, overlaps an exterior cover of a storage one above the lower storage in the vertical direction when viewed in a horizontal direction.