Image forming apparatus, paper bundling apparatus, and paper bundling method using image forming apparatus

A paper bundling apparatus, comprising:

• an image forming unit that forms images on paper sheets;
• a paper transfer unit that transfers the paper sheets toward the image forming unit;
• a skew correcting unit that corrects the skew of the paper sheets transferred by the paper transfer unit, with reference to paper ends parallel to a transfer direction of the paper sheets and allows after the correction other paper sheets to reach the image forming unit without performing another skew correction;
• a register control portion that registers the paper sheet by using a register roller that moves in a direction perpendicular to a path of the paper sheet in order to register the paper sheet to a predetermined position;
• and
• an align unit that bundles the paper sheets having the image formed by the image forming unit, by receiving and stacking the paper sheets having the images and by registering the paper ends, which were referred to by the skew correcting unit, at the stacking time.

A paper bundling method using an image forming apparatus having an image forming unit that forms an image on a paper sheet, a paper transfer unit that transfers the paper sheet toward the image forming unit, a skew correcting unit that corrects the skew of the paper sheet transferred by the paper transfer unit, with reference to the paper end parallel to a transfer direction of the paper sheet and a register control portion, comprising the steps of:

• causing the paper transfer unit to transfer the paper sheet toward the image forming unit, after the skew correcting unit corrected the skew of the paper sheet to be conveyed to the paper transfer unit, without performing another skew correction on the paper sheet;
• registering the paper sheet using a register roller of the register control portion that moves in a direction perpendicular to a path of the paper sheet to register the paper to a predetermined position;
• forming an image on the paper sheet, as corrected in its skew by the skew correcting unit, by the image forming unit when the corrected paper sheet reaches the image forming unit;
• making a bundle of the paper sheets having the images formed by the image forming unit, by receiving and stacking the paper sheets and by registering the paper ends which were referred to at the stacking time by the skew correcting unit;
• stitching the paper sheet bundle;
• folding the stitched paper sheet bundle with reference to the stitched portion;
• and
• cutting the folded paper sheet bundle at a portion near the end portion thereof.