Patent ID: 6729781
Filing Date: 2004-05-04
Classification: B41J,G06K

Abstract:
An image forming apparatus comprising a printer engine, a plurality of external devices, first and second connectors for connecting said printer engine to first and second external devices among said plurality of external devices, and a control unit having an alternate operation mode for performing alternating communication with said first and second external devices by switching communication at a predetermined cycle, wherein said control unit, during communication with either one of said first and second external devices, is for enabling reception of commands and/or a print-start signal from either one of said first and second external devices and refusing reception of commands and a print-start signal from the other external device; and for providing an interval during which reception of commands and a print-start signal from both external devices is refused for a predetermined period of time when communication is changed over from one external device to another external device.