Sheet conveying device, image forming apparatus with sheet conveying device, and method of correcting skew of sheet by using sheet conveying device

A method of correcting a skew of a sheet via a sheet conveying device, the method comprising:

• conveying a sheet downstream along a sheet conveyance path with a pair of conveyance rollers toward a pair of registration rollers in a sheet conveyance direction while sandwiching the sheet therebetween;
• separating the pair of registration rollers from each other to open the sheet conveyance path to allow the sheet conveyed by the pair of conveyance rollers to pass therethrough;
• conveying, via a pair of bumping rollers, the sheet inclining from the sheet conveyance direction though the pair of registration rollers when the pair of registration rollers are separated from each other, the pair of bumping rollers being between the pair of conveyance rollers and the pair of registration rollers;
• bumping a leading end of the sheet with the pair of bumping rollers against a sheet skew corrector downstream of the pair of registration rollers in the sheet conveyance direction;
• correcting a skew of the leading end of the sheet with the sheet skew corrector by further conveying the sheet after bumping the leading end of the sheet against the sheet skew corrector downstream for a period of time to form a deflection in the sheet;
• sandwiching the sheet with the skew of the leading end corrected by bringing the pair of registration rollers in contact with each other to close the sheet conveyance path such that the pair of registration rollers close to sandwich the sheet before the pair of bumping rollers and a pair of driving rollers separate from each other;
• separating the pair of bumping rollers from each other to open the sheet conveyance path such that, the sheet with the deflection formed therein is held by only the pair of registration rollers sandwiching the leading end of the sheet and the pair of conveyance rollers sandwiching a trailing end of the sheet;
• retracting the sheet skew corrector from the sheet conveyance path to open the sheet conveyance path;
• driving the pair of registration rollers sandwiching the sheet therebetween at a prescribed time;
• conveying the sheet downstream of the sheet skew corrector in the sheet conveyance direction with the pair of registration rollers;
• and
• continuously sandwiching the sheet with the pair of conveyance rollers from a first time to a second time, the first time being a time when the sandwiching sandwiches the sheet with the skew of the leading end corrected by bringing the pair of registration rollers in contact with each other to close the sheet conveyance path and the second time being a time when the trailing end of the sheet with the skew of the leading end corrected passes between the pair of conveyance rollers.