Patent ID: 8514437

Claim:
An image forming apparatus, comprising: a main body which comprises an image forming unit forming an image to a printing medium; and a plurality of mail box modules which are disposed to an output side of the printing medium in the main body to have a plurality of steps, and respectively comprise a driving unit driving so that the printing medium can be selectively output from the main body, and a control circuit unit controlling a driving of the driving unit, the control circuit unit of each of the mail box modules comprising: a shift register which comprises channels corresponding to the total number of the plurality of mail box modules, and, if receiving an identifying ID information of the mail box module from the main body, turns on one channel of the channels corresponding to the identifying ID information; and a multiplexer which outputs an active signal driving the driving unit to the driving unit if the channel turned on by the shift register corresponds to a predetermined identifying ID, wherein the respective control circuit units of the mail box modules share a signal line.