Patent ID: 7046953

Claim:
An image forming apparatus having an automatic document feeder, comprising: (a) a document feeder for taking up a document from a document bundle placed on a document tray; (b) a first conveyance device for conveying the document from the document feeder to a conveyance path on a downstream side; (c) a second conveyance device for receiving the document from the first conveyance device and conveying the document to a conveyance path on a further downstream side; (d) a document sensor provided in a conveyance path between the first conveyance device and the second conveyance device for detecting a trailing edge of the document; and (e) a controller for repeatedly performing a conveyance control to convey the document from the document tray by driving the document feeder, the first conveyance device and the second conveyance device, wherein the controller has a normal mode to perform a normal-size conveyance control by taking up each document from a bundle of documents having the same size, and a multi-size mode to perform a multi-size conveyance control by taking up each document from a bundle of documents having various sizes, and wherein the normal mode is carried out, the controller controls to stop the document after a first preset time passes after a trailing edge of the document has been detected, and when the multi-size mode is carried out, the controller controls in place of using the first preset time by a second preset time which is set to be a longer time than the first preset time.