Patent ID: 7099603

Claim:
An image forming apparatus comprising: an image forming unit that forms at least one image on a sheet; a double-sided sheet conveying path which the sheet passes when being conveyed back to said image forming unit again to form an image on an opposite side surface of the sheet after an image is formed on one side surface of the sheet; a retaining member that is provided on said double-sided sheet conveying path to retain the sheet on said double-sided sheet conveying path; a post-processing device that carries out post-processing on sheets on which images have been formed by said image forming unit; a controller that controls conveyance of the sheet; a conveying destination designating device that designates said double-sided sheet conveying path as a conveying destination of the sheet on which at least one image has been formed by said image forming unit when said post-processing device is carrying out post-processing, and designates said post-processing device as the conveying destination of the sheet on which at least one image has been formed by said image forming unit, when said post-processing device is not carrying out post-processing; an image forming mode input device that inputs an image forming mode; and a retention determining device that determines whether said retaining member is to retain the sheet on which at least one image has been formed by said image forming unit, based on the input image forming mode, wherein said controller provides control to convey the sheet on which the at least one image has been formed by said image forming unit to said double-sided sheet conveying path, cause said retaining member to temporarily retain the sheet on said double-sided sheet conveying path, and then convey the sheet to said post-processing device, wherein said controller provides control to convey the sheet on which at least one image has been formed by said image forming unit to the conveying destination designated by said conveying destination designating device, and wherein said retention determining device determines that said retaining member is not to retain the sheet when the input image forming mode is a mode in which images are formed on opposite side surfaces of the sheet.