Abstract: The invention relates to an arrangement in inkjet printers of the kind in which ink droplets are propelled through a nozzle and onto a recording medium in response to an impulse. The arrangement includes a detachable ink container which includes the nozzle through which ink droplets are propelled, and an ink chamber which is located adjacent to the nozzle. The ink chamber is defined on at least one side by an elastic wall, and adjacent to the elastic wall there is provided a shock-wave generating device. When the device is activated, it moves axially into impact with the elastic wall, such as to generate a shock wave which propagates through the ink chamber and causes an ink droplet to be propelled through the nozzle.