To provide a printer wherein an imaging apparatus connected to the printer by a cable can photograph an object while the printer prints out an image photographed by the imaging apparatus.

A digital camera 12 and the printer 14 are connected via a USB cable 16. A master storage driver 56 provided with the printer 14 applies an operating voltage of +5V to a power supply wire of the USB cable 16 to allow the printer 14 to control the digital camera 12 as a master storage device. The digital camera 12 transmits image data to the printer 14. After the end of transmission, the master storage driver 56 stops application of the voltage to the power supply wire of the USB cable 16. Since the digital camera 12 is released from the operation as the master storage device, the digital camera can carry out photographing even when the printer 14 prints out the image of the digital camera 12.