| 摘要 |
A portable electro-mechanical printer has a platen (1) over which electro-sensitive paper is advanced, relative to a print head (6) having a few row of selectively energizable needles (8) which is movable by an electric motor transmission (18,19,21,24) parallel to the platen in a scanning direction transverse the row of needles. A timing disc (25) is driven by the drive transmission, the disc being subdivided into sectors and cooperating with two relatively displaced photocells (26,27) which produce two periodic signals upon rotation of the disc, these signals being utilized to provide clock pulses controlling successive energizations of the print head needles as the latter is scanned across the paper.
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