Sheet processing apparatus

Abstract

A sheet processing apparatus in an embodiment includes a processing unit, a tray, alignment members, and a supporting member. The processing unit processes regular size sheets. The regular size sheets can be placed on a first surface of the tray. The alignment members are capable of coming into contact with end portions in a first direction, in which a line of intersection of the first surface and a horizontal plane extends, further in an upward direction than a center of gravity of a largest regular size sheet present in an initial position where the regular size sheet entering the tray is placed first. The supporting member supports a lower end portion of the largest regular size sheet and extends from inner sides to outer sides of end portions of the largest regular size sheet in the first direction.

What is claimed is: 
     
         1 . A sheet processing apparatus, comprising:
 a processing component configured to process regular size sheets that comprise sheets of different sizes;   a tray having a first surface on which the regular size sheets are placeable;   alignment members configured to, if a direction in which a line of intersection of the first surface and a horizontal plane extends is represented as a first direction, a direction parallel to the first surface and perpendicular to the first direction is represented as a second direction, a regular sheet of the regular size sheets determined to have a largest length in the second direction among the regular size sheets placed on the tray is represented as a largest regular size sheet, and a position in the second direction where the regular size sheets entering the tray are placed first is represented as an initial position, come into contact with end portions in the first direction further in an upward direction than a center of gravity of the largest regular size sheet present in the initial position; and   a supporting member configured to support both the largest regular size sheets and the smallest regular size sheet to be the upper end portion of the largest regular size sheet and the upper end portion of the smallest regular size sheet are in the same upper end portion position, the supporting member extends from inner sides to outer sides of end portions of the largest regular size sheet in the first direction,   wherein, if the regular size sheet having a smallest length in the second direction among the regular size sheets placed on the tray is represented as a smallest regular size sheet, the alignment members are configured to come into contact with end portions in the first direction further in a downward direction than a center of gravity of the smallest regular size sheet present in the initial position.   
     
     
         2 . The sheet processing apparatus according to  claim 1 , wherein the supporting member extends from an outer side of a first end portion to an outer side of a second end portion of the largest regular size sheet in the first direction. 
     
     
         3 . The sheet processing apparatus according to  claim 1 , wherein the supporting member includes a first supporting member extending from an inner side to an outer side of a first end portion of the largest regular size sheet in the first direction and a second supporting member extending from an inner side to an outer side of a second end portion of the largest regular size sheet in the first direction. 
     
     
         4 . The sheet processing apparatus according to  claim 1 , wherein
 the supporting member includes a low friction member in a contact portion with a lower end portion of the largest regular size sheet, and   a coefficient of friction of the low friction member is smaller than a coefficient of friction between a stacked pair of the regular size sheets.   
     
     
         5 . The sheet processing apparatus according to  claim 1 , wherein
 the processing component includes a blade configured to come into contact with a center in the second direction of the largest regular size sheet, and   the alignment members are present in the upward direction of the blade.   
     
     
         6 . The sheet processing apparatus according to  claim 1 , wherein the alignment members do not come into contact with end portions in the first direction further in a downward direction than the center of gravity of the largest regular size sheet present in the initial position. 
     
     
         7 . The sheet processing apparatus according to  claim 1 , wherein the sheet processing apparatus does not include members that come into contact with end portions in the first direction further in a downward direction than the center of gravity of the largest regular size sheet present in the initial position. 
     
     
         8 . The sheet processing apparatus according to  claim 1 , wherein the supporting member is movable in the second direction. 
     
     
         9 . The sheet processing apparatus according to  claim 1 , wherein the supporting member is positioned perpendicular to a saddle forming tray. 
     
     
         10 . The sheet processing apparatus according to  claim 1 , wherein the alignment members do not move in the second direction. 
     
     
         11 . The sheet processing apparatus according to  claim 1 , wherein the regular size sheets comprise at least one selected from A4 sheets, B5 sheets, American letter sized sheets, and legal sized sheets. 
     
     
         12 . An image forming apparatus, comprising:
 an image forming component; and   a sheet processing apparatus, comprising:
 a processing component configured to process regular size sheets that comprise sheets of different sizes; 
 a tray having a first surface on which the regular size sheets are placeable; 
 alignment members configured to, if a direction in which a line of intersection of the first surface and a horizontal plane extends is represented as a first direction, a direction parallel to the first surface and perpendicular to the first direction is represented as a second direction, a regular size sheet of the regular size sheets determined to have a largest length in the second direction among the regular size sheets placed on the tray is represented as a largest regular size sheet, and a position in the second direction where the regular size sheets entering the tray are placed first is represented as an initial position, come into contact with end portions in the first direction further in an upward direction than a center of gravity of the largest regular size sheet present in the initial position; and 
 a supporting member configured to support both the largest regular size sheets and the smallest regular size sheet to be the upper end portion of the largest regular size sheet and the upper end portion of the smallest regular size sheet are in the same upper end portion position, the supporting member extends from inner sides to outer sides of end portions of the largest regular size sheet in the first direction, 
   wherein, if the regular size sheet having a smallest length in the second direction among the regular size sheets placed on the tray is represented as a smallest regular size sheet, the alignment members are configured to come into contact with end portions in the first direction further in a downward direction than a center of gravity of the smallest regular size sheet present in the initial position.   
     
     
         13 . The image forming apparatus according to  claim 12 , wherein the supporting member extends from an outer side of a first end portion to an outer side of a second end portion of the largest regular size sheet in the first direction. 
     
     
         14 . The image forming apparatus according to  claim 12 , wherein the supporting member includes a first supporting member extending from an inner side to an outer side of a first end portion of the largest regular size sheet in the first direction and a second supporting member extending from an inner side to an outer side of a second end portion of the largest regular size sheet in the first direction. 
     
     
         15 . The image forming apparatus according to  claim 12 , wherein
 the supporting member includes a low friction member in a contact portion with a lower end portion of the largest regular size sheet, and   a coefficient of friction of the low friction member is smaller than a coefficient of friction between a stacked pair of the regular size sheets.   
     
     
         16 . The image forming apparatus according to  claim 12 , wherein the alignment members do not come into contact with end portions in the first direction further in a downward direction than the center of gravity of the largest regular size sheet present in the initial position. 
     
     
         17 . The image forming apparatus according to  claim 12 , wherein the image forming apparatus does not include members that come into contact with end portions in the first direction further in a downward direction than the center of gravity of the largest regular size sheet present in the initial position. 
     
     
         18 . A sheet processing method for processing regular size sheets that comprise sheets of different sizes, comprising:
 placing the regular size sheets on a first surface of a tray;   if a direction in which a line of intersection of the first surface and a horizontal plane extends is represented as a first direction, a direction parallel to the first surface and perpendicular to the first direction is represented as a second direction, a regular size sheet of the regular size sheets determined to have a largest length in the second direction among the regular size sheets placed on the tray is represented as a largest regular size sheet, and a position in the second direction where the regular size sheets entering the tray are placed first is represented as an initial position, bringing alignment members into contact with end portions in the first direction further in an upward direction than a center of gravity of the largest regular size sheet present in the initial position; and   supporting both the largest regular size sheets and the smallest regular size sheet to be the upper end portion of the largest regular size sheet and the upper end portion of the smallest regular size sheet are in the same upper end portion position, the supporting member extending from inner sides to outer sides of end portions of the largest regular size sheet in the first direction,   the sheet processing method further comprising:   if the regular size sheet having a smallest length in the second direction among the regular size sheets placed on the tray is represented as a smallest regular size sheet, bringing the alignment members into contact with end portions in the first direction further in a downward direction than a center of gravity of the smallest regular size sheet present in the initial position.   
     
     
         19 . The sheet processing method according to  claim 18 , further comprising:
 bringing a blade into contact with a center in the second direction of the largest regular size sheet, wherein   the alignment members are present in the upward direction of the blade.