Patent attributes
At step S301, since none of conveyance sensors 114, 116 and 121 detect residual paper, a CPU 203 notifies a CPU 201 that it is in a residual paper check start instruction waiting mode. At step S302, since a conveying path sensor 111 in an optional paper feed unit 101 does not detect residual paper, the CPU 202 notifies the CPU 201 that it is in a residual paper check start instruction waiting mode. At step S303, since an inlet sensor 122 of an optional paper output unit 103 does not detect residual paper, the CPU 204 notifies the CPU 201 that it is in a residual paper check start instruction waiting mode. After confirming that all the units are in the waiting mode, the CPU 201 issues a residual paper check start instruction to all the units simultaneously to improve usability by reducing initializing time.