Sheet conveying device and image forming apparatus

A sheet conveying device for conveying a sheet, the sheet conveying device comprising:

• a sensor configured to sense a position of a side end of the sheet in the width direction;
• a displacement-amount detecting unit configured to detect an amount of displacement of a conveyed sheet from a conveyance reference in a width direction being substantially perpendicular to a sheet conveying direction in response to a signal from the image sensor;
• a pair of sheet conveying rollers configured to be shiftable in a direction substantially perpendicular to the sheet conveying direction while pinching the sheet having the amount of displacement detected by the displacement-amount detecting unit, and the pair of sheet conveying rollers are coaxially disposed in the direction substantially perpendicular to the sheet conveying direction;
• and
• a gap changing portion configured to change the gar between the sheet conveying rollers based on a length of the conveyed sheet in the width direction,
• wherein, before the sheet reaches the sheet conveying rollers, the sheet conveying rollers are shifted such that a center of a gap between the pair of sheet conveying rollers matches with a center of the conveyed sheet in the width direction and, after the sheet reaches the sheet conveying rollers, the sheet conveying rollers are shifted while pinching the sheet such that the center of the gap between the sheet conveying rollers matches with a conveyance-reference position.

An image forming apparatus for forming an image on a sheet using an image forming portion, the image forming apparatus comprising:

• a sensor configured to sense a position of a side end of the sheet in the width direction;
• a displacement-amount detecting unit configured to detect an amount of displacement of a sheet conveyed toward the image forming portion from a conveyance reference in a width direction being substantially perpendicular to a sheet conveying direction in response to a signal from the image sensor;
• a pair of sheet conveying rollers configured to be shiftable in a direction substantially perpendicular to the sheet conveying direction while pinching the sheet having the amount of displacement detected by the displacement-amount detecting unit, and the pair of sheet conveying rollers are coaxially disposed in the direction substantially perpendicular to the sheet conveying direction;
• and
• a gap changing portion configured to change the gar between the sheet conveying rollers based on a length of the conveyed sheet in the width direction,
• wherein, before the sheet reaches the sheet conveying rollers, the sheet conveying rollers are shifted such that a center of a gap between the pair of sheet conveying rollers matches with a center of the conveyed sheet in the width direction, and, after the sheet reaches the sheet conveying rollers, the sheet conveying rollers are shifted while pinching the sheet such that the center of the gap between the sheet conveying rollers matches with a conveyance-reference position.