Comparison and control unit for two printer numbering devices - has type wheels with mechanical optical or magnetic signalling means for each type position

摘要

Signal generators (2, 22) are connected to a comparator control unit (4) and function mechanically, optically or magnetically, preferably via a signal amplifier. The digital working comparator unit has its output signal from a N AND-gate (43) acting on a switching relay (46) for a signal unit or switching unit (45) of the machine. In one design each of the numbering units have flexible photoconductors (2) associated with them, and the type wheels have at each typing position bright and dark surfaces in uniform alternating sequence. Each photoconductor is two-armed and a common light source is provided for all conductors.