PURPOSE: To provide a printer capable of transmitting the operating condition of a recorder to a host computer and receiving a printing command corresponding to the operating condition, wherein a connecting means is provided for connection between a controlling part in a recorder and a host computer in both directions.

CONSTITUTION: In the recorder 1, an interface 12 is oprovided intermediately between the controlling part 11 in the recorder 1 and an external host computer 2. The controlling part 11 is connected with a sensor 13 for the residual amount of an ink, a sensor 14 for bubbles present in the ink, a recording paper sensor 15 for detecting the presence or absence of a recording paper, or the like, and detects supply of the ink, resetting from clogging, supply of the paper or other conditions through a mechanical system controlling part 16. These kinds of information are transmitted to the host computer 2 through the interface 12, and the host computer 12 transmits a printing command corresponding to these kinds of information.