Sheet processing apparatus and image forming system

A sheet processing apparatus for performing folding processing on a sheet, comprising:

• a transport path including a guide face to guide a transported sheet;
• a rotating body pair adapted to nip the sheet transported to the transport path by a nip portion to rotate, and thereby draw the sheet to perform folding processing;
• a folding blade including a front edge portion for pushing the sheet transported to the transport path to the nip portion of the rotating body pair, and shifting among a first position in which the front edge portion is retracted from the transport path, a second position at a moment in which the front edge portion protrudes to the transport path from the first position, and a third position in which the front edge portion pushes the sheet to the nip portion of the rotating body pair;
• a blade guide member including a guide portion for pushing the sheet so as to bring near to the rotating body pair, when the folding blade pushes the sheet to the nip portion in executing the folding processing;
• and
• a shift section to shift the folding blade and the blade guide member in a push direction for pushing to the nip portion and in a return direction opposite to the push direction,
• wherein in the second position, the front edge portion of the folding blade protrudes in the push direction more than the guide portion, and
• wherein the shift section shifts the folding blade and the blade guide member relatively so that a distance from the front edge portion in the third position to the guide portion is longer than a distance from the front edge portion in the second position to the guide portion.

A sheet processing apparatus for performing first folding processing on a sheet, subsequently performing second folding processing in a position different from a fold formed by the first folding processing, and performing folding processing so that one end of a folded sheet folded by the first folding processing exists inside the sheet folded, comprising:

• a transport path including a guide face to guide a transported sheet to be transported in a predetermined transport direction;
• a rotating body pair adapted to nip the sheet transported to the transport path by a nip portion to rotate, and thereby draw the sheet to perform folding processing;
• a folding blade including a front edge portion for pushing the sheet transported to the transport path to the nip portion of the rotating body pair, and shifting among a first position in which the front edge portion is retracted from the transport path, a second position in which the front edge portion protrudes to the transport path by a predetermined amount, and a third position in which the front edge portion pushes the sheet to the nip portion of the rotating body pair;
• a blade guide member including a guide portion for pushing the one end of the sheet folded by the first folding processing so as to bring near to the rotating body pair, when the folding blade pushes the sheet to the nip portion in executing the second folding processing;
• and
• a shift section to shift the folding blade and the blade guide member in a push direction for pushing to the nip portion and in a return direction opposite to the push direction,
• wherein in a state where the folded sheet is positioned in the transport path in executing the second folding processing, the guide portion is positioned more than the front edge portion to a folding line side formed by the first folding processing in the transport direction, and
• wherein the shift section shifts the folding blade and the blade guide member relatively so that a distance from the front edge portion in the third position to the guide portion is longer than a distance from the front edge portion in the second position to the guide portion.