Sheet forwarding apparatus for determining causes of feeding defects

A sheet forwarding apparatus for feeding a sheet from a stack of sheets in a sheet-storing means to an image forming unit of an image forming apparatus, comprising:

• sheet-forwarding means for forwarding sheets one by one from said sheet-storing means to an image forming unit;
• operation counter means for counting a number of operations of said sheet-forwarding means;
• instructing means for instructing said sheet-forwarding means to start a sheet forwarding operation;
• detecting means for detecting whether a sheet is forwarded from said sheet-storing means;
• detection counter means for counting the number of times forwarding of a sheet is detected by said detecting means;
• controlling means for operating said sheet-forwarding means a first predetermined number of times after said instructing means has instructed a start of the sheet forwarding operation or until said detecting means detects that a sheet is forwarded, whichever occurs earlier;
• error processing means for performing an error process when said detecting means does not detect that a sheet is forwarded after the sheet forwarding operation of said sheet-forwarding means is repeated said first predetermined number of times;
• and
• determining means for determining a state of said sheet-forwarding means by comparing an operation count of said operation counter means with a detection count of said detection counter means.