A dispenser head includes a body defining two housings, which receive a respective nozzle-carrier provided with a nozzle. Each ROM cell has a first and second regions of a second conductivity type spaced apart from one another in the substrate. The incidence optical system has different optical powers in the first scanning direction and the second scanning direction, and makes light incident on the scanning device in a convergent state in the first scanning direction and in a substantially parallel light state in the second scanning direction.