Bookbinding Method and Bookbinding Unit, and Image-Forming System

An image-forming system comprising:

• a data processor having a series of image data and at least one folding-image data;
• image-forming means for forming an image on a sheet based on predetermined image data form the data processor;
• sheet folding means for folding a sheet conveyed from the image-forming means;
• stacking means for collating and stacking sheets conveyed from the sheet folding means or the image-forming means;
• binding means for binding a spine edge of a sheet bundle conveyed from the stacking means;
• trimming means for trimming true at least a fore-edge portion of the sheet bundle bound by the binding means;
• and
• control means for controlling the image-forming means, folding means and trimming means;
• wherein
• the control means is configured
• (1) to control the image-forming means to sequentially form images on sheets based on the series of image data and to form images of at least one selected image data on the same sheet in parallel to the folded-image data;
• (2) to control the sheet folding means to fold the sheet with the foldout image formed at a folding-back fold location;
• and at the folding step, the foldout-image area is folded at a folding-back fold location;
• and
• (3) to control the trimming means to trim at a position to cut free the folding position.

A bookbinding apparatus comprising:

• a sheet conveyance-in path for sequentially supplying sheets;
• sheet folding means for folding a sheet conveyed from the sheet conveyance-in path;
• stacking means for collating and stacking sheets conveyed from the sheet folding means or the sheet conveyance-in path;
• binding means for binding a spine edge of a sheet bundle conveyed from the stacking means;
• trimming means for trimming true at least a fore-edge portion of the sheet bundle bound by the binding means;
• and
• control means for controlling the folding means and trimming means;
• wherein
• the control means is configured
• to control the sheet folding means to fold the sheet with the foldout image formed at a folding-back fold location;
• and at the folding step, the foldout-image area is folded at a folding-back fold location;
• and
• to control the trimming means to trim at a position to cut free the folding position.