Patent ID: 7377506

Claim:
An image forming apparatus having a plurality of paper feed units capable of setting index sheets, comprising: a storage section which stores size information, type information and index number information indicating the number of index sheets per set of paper sheets set in each paper unit in a case where index sheets are set in the plurality of paper feed units; a determining section which determines whether index number information of a first paper feed unit coincides with that of a second paper feed unit or that of a third paper feed unit; a first control section which performs processing of automatically changing the paper feed unit to be used from the first paper feed unit to the second paper feed unit and does not perform processing of automatically changing the paper feed unit from the first paper feed unit to the third paper feed unit in a case where paper sheets are set in the first paper feed unit are run out, the type information of the first paper unit indicates an index sheet, and all of the elements of a first predetermined condition are satisfied; and a second control section which performs processing of automatically changing the paper feed unit to be used from the first paper feed unit to the second paper feed unit and does not perform processing of automatically changing the paper feed unit from the first paper feed unit to the third paper feed unit in a case where paper sheets set in the first paper feed unit are run out, the type information of the first paper feed unit does not indicate the index sheet, and all of the elements of a second predetermined condition are satisfied, wherein the first predetermined condition is that the size information, type information and the index number information of the first paper feed unit coincide with those of the second paper feed unit, and at least one of the size information, the type information and the index number information of the first paper feed unit do not coincide with those of the third paper feed unit, and the second predetermined condition is that the size information and type information of the first paper feed unit coincide with those of the second paper feed unit, and at least one of the size information and type information of the first paper feed unit do not coincide with those of the third paper feed unit.