Matrix printer and interchangeable container for color ink supply

A matrix printer having a moveable print head, at least one interchangeable ink container for a printing-ink supply and having an interior space free of printing ink, and a holder to hold the interchangeable container, a means for preventing operation of the printer with an improper ink container, said means comprising:

• a first switch to block and enable the printing operation,
• a mechanical signal transmitter and a mechanical signal receiver arranged on the holder, and
• a mechanical signal transmitting device arranged in the interior space of the interchangeable container for transmitting a mechanical input signal from the mechanical signal transmitter to the mechanical signal receiver during or upon an insertion of the interchangeable container into the holder,
• the signal transmitter during the insertion of the interchangeable container being moveable into the interior space of the interchangeable container through an opening in a wall of the interchangeable container,
• said signal receiver being associated with said switch so that an input signal from the signal transmitter is transmitted to the signal receiver by the signal transmitting device and is converted to an output signal applied to the signal receiver and through the signal receiver to the switch.