Abstract: The printer has a standby station (3) including a main movable support (4) on which is mounted slidably and resiliently by virtue of a spring (14), a main cap (5) integral with a cap carrier (6). An exchangeable printer head (8) plugged onto a traveller is moved towards the standby station facing the main cap (5) which is subsequently applied against the nozzles of the printer head. At least one second printer head (10) of another type can be plugged onto the traveller. A selection member (11) provided on the second head (10) controls the positioning of a secondary cap (12) inserted between the main cap (5) and the second printer head (10). This secondary cap (12) is then applied by the action of the main movable support (4) against the second printer head to prevent the drying of the ink. The soiling of the printer head by the ink of another printer head can. thus be avoided by virtue of a standby station of a very simple construction which can be adapted to existing printers.