1. An imaging apparatus capable of outputting a sensed image to a printing apparatus, comprising: issuing means for issuing a print request command containing a parameter for designating a print mode to the printing apparatus connected via an interface; transmission means for transmitting image data corresponding to the print mode on the basis of a data request from the printing apparatus; and means for transmitting, to the printing apparatus, the print request command in which the parameter for designating printing of the image data transmitted by said transmission means is changed to invalid data.