PRINTER

PURPOSE:To improve facility for a user by permitting the execution of a non- printing processing mode and continuing operation at the non-printing processing mode without interruption by the user even when a cover is opened. CONSTITUTION:When a user opens a top cover 16 for exchanging a ribbon cassette 12, a cover-open flag is turned 'ON', and a non-printing processing mode is decided. Processing at the non-printing processing mode is permitted on the non-printing processing mode at that time, and the user can continue work such as the composition, edition, etc. of a document file at a word processor mode. Since the cover-open flag is turned 'ON' previously in this case even when the top cover 16 is after that, the processing of mode decision is executed positively. Even when the top cover 16 is opened and closed any time during that time, the cover-open flag is kept under the state in which it is left as it is turned 'ON'. Accordingly, the facility of the user can be improved while trouble by unnecessary origin-detection operation can be solved.