Sheet feeding device and image forming apparatus

A sheet feeding device comprising:

• a feeding mechanism including a feeding rotating body configured to contact an upper surface of a topmost sheet of a stack of sheets, a feed-out rotating body that is spaced apart from the feeding rotating body, and a separating member that is positioned below the feed-out rotating body and biased toward the feed-out rotating body, the feeding mechanism rotating the feeding rotating body and the feed-out rotating body to execute a feeding process of feeding sheets from the stack of sheets to a conveying path, and separating accompanying sheets that are fed out accompanying each sheet from each sheet by the separating member;
• a displacement mechanism configured to be able to switch between a contact state in which the stack of sheets contacts the feeding rotating body and a separation state in which the stack of sheets is separated from the feeding rotating body by displacing the stack of sheets or the feeding rotating body;
• and
• a sheet detecting device configured to detect each sheet at a position on a downstream side of the feed-out rotating body and the separating member in a sheet feeding direction;
• a timing device configured to measure an elapsed time from a time when the feeding process for each sheet is started to a time when each sheet is detected by the sheet detecting device;
• a return mechanism configured to execute a sheet return process to return, when the displacement mechanism switches from the contact state to the separation state, a positionally deviated sheet among the stack of sheets that has been positionally deviated to a downstream side in the sheet feeding direction with respect to an initial reference position to an upstream side in the sheet feeding direction;
• a processing device configured to derive a positional deviation amount representing a deviation amount of a position of a target sheet relative to the initial reference position at a time when the feeding process for the target sheet is started, based on a preset reference feeding time and a target measurement time measured by the timing device for the target sheet fed by the feeding process;
• and
• a control device that causes the return mechanism to execute the sheet return process when the positional deviation amount satisfies a predetermined positional deviation condition.