Sheet storing apparatus

A sheet storing apparatus in which a sheet is discharged to a processing tray and a stack tray from either of a first sheet discharging port and a second sheet discharging port which are arranged as being distanced in a conveying direction, comprising:

• a sheet discharging path which guides a sheet conveyed to an introducing port toward the first sheet discharging port;
• the processing tray which is arranged at the downstream side as forming a step against the first sheet discharging port;
• the second sheet discharging port which is arranged above the processing tray at a position being distanced from the first sheet discharging port;
• the stack tray which is arranged at the downstream side of the second sheet discharging port;
• a first conveying roller which discharges a sheet to the first sheet discharging port as being arranged on the sheet discharging path;
• a second conveying roller which is capable of being rotated forwardly and reversely to convey a sheet selectively to the processing tray and the stack tray as being arranged between the first sheet discharging port and the second sheet discharging port;
• corrugation forming means which forms a plurality of corrugations aligned in the direction perpendicular to the conveying direction on a sheet proceeding from the first conveying roller to the second conveying roller;
• and
• de-curling means which is arranged between the second conveying roller and a sheet placement face of the stack tray to correct the corrugation formed on a sheet to be flat, so that the number of corrugations of a sheet proceeding from the second conveying roller to the stack tray is smaller than the number of corrugations of a sheet proceeding from the first conveying roller to the second conveying roller,
• wherein the first and second conveying rollers are structured respectively with a plurality of roller pairs which are aligned at a predetermined interval in the direction perpendicular to the conveying direction, and
• a section having an engagement width in the direction perpendicular to the conveying direction between a sheet and the plurality of second conveying rollers located at the downstream side is narrower than a section having an engagement width in the direction perpendicular to the conveying direction between a sheet and the plurality of first conveying rollers.