Sheet conveying apparatus and image forming apparatus

An image forming apparatus comprising:

• sheet conveying portion having,
• an upstream roller which conveys a sheet;
• a downstream roller which is installed downstream from the upstream roller and conveys the sheet conveyed by the upstream roller, wherein the sheet conveyed by the upstream roller abuts the downstream roller to form a loop in the sheet so as to correct for skew of the sheet;
• a driving apparatus which rotates the downstream roller forward or backward, wherein if the driving apparatus rotates the downstream roller forward, the sheet is conveyed downstream in the conveying direction, and if the driving apparatus rotates the downstream roller backward, the sheet is conveyed upstream in the conveying direction;
• a detection portion which detects the skew of the sheet before the sheet conveyed by the upstream roller abuts the downstream roller;
• and
• a controller which determines the backward rotation amount for the downstream roller to rotate backward based on the detection results of the detection portion and controls the driving apparatus to rotate the downstream roller backward based on the backward rotation amount determined by the controller with the sheet conveyed by the upstream roller abutting the downstream roller,
• and,
• image forming portion which forms image on the sheet conveyed from the sheet conveying portion.