Abstract: The invention relates to an opto-electronic scanning apparatus with a document support on a common frame, and a scanning head scanning a document in two different directions, which is characterized in that on the frame a first carrier (4; 27) is mounted that can be driven by a first driving means (5; 18) in the first direction, that on the first carrier (4; 27) a second carrier (12) is mounted which carries a scanning head (16, 17) operating in the second scanning direction only, that the scanning head (16, 17) on the second carrier (12) is linearly movable in the second scanning direction only, and that for each direction of movement a separate driving means is provided.

Abstract: Impact printing apparatus for recording at different character densities having an interposer unit movable between a plurality of print hammers and type chain to provide a translation function for the variable character-to-character distances required of the different character densities. During low density recording the interposer unit renders ineffective certain of the print hammers otherwise used for the higher density. A single type chain may be used with different interposer arrangements to obtain the various densities or type chains of different densities can be used.