PURPOSE: To conserve the power consumption of the whole of a printer by reducing the ratio of power consumption of the printer during a standby period by controlling the power consumption of the whole of the printer by controlling the supply of power to a printing output means on the basis of the data received from a data processor.

CONSTITUTION: The control part 2 of a printers constituted so that the input data such as a control code from an external device 3 such as a host computer is received by an input part 4 and the control code is analyzed by a control code analyzing part 5 and the image signal outputted to an output mechanism 9 is formed on the basis of the control code in an output part 6. A data input detection part 7 detects the input data from the external device 3 to send a command setting the control part 2 and the output mechanism 9 to a current supply state to a power supply control part 8. A power supply part 10 supplies power of predetermined potential to the control part 2 and the output mechanism 9. The output mechanism 9 prints a document or image on a recording medium on the basis of the printing data from the output part 6.