DRUCKER MIT EINEM VERBESSERTEN HAMMERWERK

摘要

In a selective printer of the kind having a hammerbank shuttle which is linearly reciprocated across the paper during printing, the hammerbank is reciprocable within an elongate plenum supplied with cooling air, and apertures in the hammerbank itself admit the air to electromagnetic components within the bank. As shown in cross section in Fig 13, the hammerbank 18 is reciprocably supported on shaft 82 within plenum 272. Hammersprings 16 are retracted against their natural resilience by a permanent magnet 132 between respective pole pieces 126, 128, and are released for printing when respective coils 136, 138 are energised to negate the influence of said magnet. Cooling air is directed over said coils via apertures 282, 284 and chambers 292, 288 in the hammerbank, these being so disposed as to create significant turbulence so as to maximise cooling. Air is constrained to pass between the coils rather than to leak through the interstices between springs 16 by configuring the coil bobbin flanges 134 to act as an air dam. The following matters are also disclosed: (a) the magnetic arrangement of the hammerbank (b) the mounting arrangement of the hammerbank (c) the attachment of springs in the hammerbank (d) casing arrangements for the printer <IMAGE>