Sheet processing apparatus and image forming apparatus provided therewith and sheet processing method

A sheet processing apparatus comprising:

• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position;
• and
• a conveyance path connecting said first folding unit and said second folding unit,
• wherein a length of said conveyance path is longer than a length in a conveyance direction of a foldable maximum sheet, and
• said conveyance path has a curved shape.

A sheet processing apparatus comprising:

• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position;
• and
• a conveyance path connecting said first folding unit and said second folding unit,
• wherein a length of said conveyance path is shorter than a length from said predetermined folding position of a foldable sheet to an end portion of the foldable sheet in a conveyance direction, and
• said conveyance path has a curved shape.

A sheet processing apparatus comprising:

• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• and
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position,
• wherein said first folding unit processes the sheet one by one, and
• said second folding unit folds the plurality of sheets folded by said first folding unit while superimposing the sheets on top of another, and
• said first folding unit includes a first folding roller pair which folds the sheet while conveying the sheet and a first pushing member which pushes the sheet one by one toward said first folding roller pair.

A sheet processing apparatus comprising:

• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• and
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position,
• wherein said first folding unit processes the sheet one by one,
• said second folding unit folds the plurality of sheets folded by said first folding unit while superimposing the sheets on top of another, and
• said second folding unit includes a second folding roller pair which folds the sheet or the sheet bundle while conveying the sheet or the sheet bundle and a second pushing member which pushes the sheet or the sheet bundle toward said second folding roller pair in the opposite direction to said first folding roller pair at said predetermined folding position.

An image forming apparatus comprising:

• an image forming portion which forms an image on a sheet;
• and
• a sheet processing apparatus which performs processing to the sheet or a sheet bundle on which the image is formed by said image forming portion,
• the sheet processing apparatus comprising:
• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• and
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position,
• wherein said first folding unit includes a first folding roller pair which folds the sheet or the sheet bundle while conveying the sheet or the sheet bundle and a first pushing member which pushes the sheet or the sheet bundle toward said first folding roller pair.

An image forming apparatus comprising:

• an image forming portion which forms an image on a sheet;
• and
• a sheet processing apparatus which performs processing to the sheet or a sheet bundle on which the image is formed by said image forming portion,
• the sheet processing apparatus comprising:
• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position;
• and
• a conveyance path connecting said first folding unit and said second folding unit,
• wherein a length of said conveyance path is longer than a length in a conveyance direction of a foldable maximum sheet, and
• said conveyance path has a curved shape.

An image forming apparatus comprising:

• an image forming portion which forms an image on a sheet;
• and
• a sheet processing apparatus which performs processing to the sheet or a sheet bundle on which the image is formed by said image forming portion,
• the sheet processing apparatus comprising:
• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position;
• and
• a conveyance path connecting said first folding unit and said second folding unit,
• wherein a length of said conveyance path is shorter than a length from said predetermined folding position of a foldable sheet to an end portion of the foldable sheet in a conveyance direction, and
• said conveyance path has a curved shape.

An image forming apparatus comprising:

• an image forming portion which forms an image on a sheet;
• and
• a sheet processing apparatus which performs processing to the sheet or a sheet bundle on which the image is formed by said image forming portion,
• the sheet processing apparatus comprising:
• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• and
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position,
• wherein said first folding unit processes the sheet one by one,
• said second folding unit folds the plurality of sheets folded by said first folding unit while superimposing the sheets on top of another, and
• said first folding unit includes a first folding roller pair which folds the sheet while conveying the sheet and a first pushing member which pushes the sheet one by one toward said first folding roller pair.

An image forming apparatus comprising:

• an image forming portion which forms an image on a sheet;
• and
• a sheet processing apparatus which performs processing to the sheet or a sheet bundle on which the image is formed by said image forming portion,
• the sheet processing apparatus comprising:
• a first folding unit which performs folding processing to a predetermined folding position on a sheet or a sheet bundle;
• and
• a second folding unit which folds the sheet or the sheet bundle folded by said first folding unit in an opposite direction to said first folding unit at said predetermined folding position,
• wherein said first folding unit processes the sheet one by one,
• said second folding unit folds the plurality of sheets folded by said first folding unit while superimposing the sheets on top of another, and
• said second folding unit includes a second folding roller pair which folds the sheet or the sheet bundle while conveying the sheet or the sheet bundle and a second pushing member which pushes the sheet or the sheet bundle toward said second folding roller pair in the opposite direction to said first folding roller pair at said predetermined folding position.