Dot matrix line printer

摘要

A dot matrix line printer/plotter apparatus for producing hard copy printout of digitally represented data. The apparatus utilizes one or more hammer banks, each mounted so as to shuttle across a paper web fed therepast. Each hammer bank carries a plurality of hammer assemblies, each of which can be individually actuated to print a dot as it sweeps across the paper. Each hammer bank is mounted on a circuit board which carries electronic circuitry to actuate the hammer assemblies thereon. The circuit boards are supported by leaf springs and driven by a stepper motor which shuttles the boards along linear paths to sweep each hammer assembly across a certain portion of the paper width. Each hammer assembly includes a hammer supported in a guide tube for linear movement between a retracted position and an extended position engaging the paper. A permanent magnet is provided to normally latch the hammer in its retracted position. Each hammer assembly further includes a coil energizable to null the action of the permanent magnet as to that hammer assembly and to thus permit a spring to propel the hammer to said extended position.