Rotary drum non-impact printer

Sets of radially mounted solid ink spark jet capsules are situated around the circumference of a cylindrical drum rotated at high speed. A commutation disc, mounted on one end of the drum, has a surface with spaced concentric conductive strips. Each strip corresponds to a different one of the capsules in each of the sets. The strips are divided into arcuate sections, one section for each set. The sections are aligned in groups. A line of stationary contacts, one for each of the strips, energize sections in the group aligned therewith when connected through electrical switches to a pulsed high voltage source. The mechanical commutator significantly reduces the number of electrical switches required. A single motor rotates the drum, as well as print speed and slew speed capstans.