Patent ID: 7095977

Claim:
An image forming apparatus for forming images on sheets fed from two or more sheet supplying devices detachably mountable to the image forming apparatus, said image forming apparatus comprising: a sheet transporting unit transporting said sheets fed from said sheet supplying devices; an image formation unit forming an image on a transfer member; a transfer unit transferring the image on the transfer member onto a sheet; and a control unit determining a connection position of each sheet supplying device and deciding whether to inquire of each sheet supplying device a sheet interval according to the connection position, wherein responsive to the control unit inquiring one of the sheet supplying devices, the one sheet supplying device transmits a sheet interval information according to an amount of sheets therein to the control unit, and wherein responsive to the one sheet supplying device transmitting the sheet interval information to the control unit, the control unit changes an image forming interval on the transfer member and a sheet feeding interval by the one sheet supplying device.