Nonmechanical High-Speed Printers

T SURPASS the speed limitations of more conventional approaches to printing digital infonnation, which commonly involve hard type faces coming in contact with the recording paper, some essentially nonmechanical methods have been investigated. The fundamental charflcteristic common to these systems is that character selection, positioning, and formation are accomplished without mechanical motion or contact. The next limitation, and a problem which appears to be of the same magnitude as high-speed character formation, is the permanent recording of the images once they have been formed. This does involve physical motion and related mechanical problems. In the following are described several systems which were brought to the attention of the Office of Naval Research during a recent survey. The Atomic Instrument Company has produced a high-speed direct-recording printer called the Dataprinter; see Figure 1. Developed in conjunction with an analogue-vol tage-to-digi tal-pulse converter and a digital-pulse counter, the printer is capable of recording 3-digit decimal numbers in a column at rates from 10 to 500 per second. The decimal number representation is of the dot-array type, the dots being formed by sparking tungsten-filament wires through Western Union type-L Teledeltos paper. This is a multilayer paper used in facsimile work and contains beneath the light-gray reading surface a pitch-black layer which is exposed in the sparking process. The paper, 16 millimeters wide, is run from one reel to another during the recording period, passing beneath a row of 11 tungsten wires. One wire is used to provide timing marks, one is for sign indication, and the remaining nine are divided into three groups of three wires per digit. Pulses may be delivered to some or all of the digit wires up to five times for a given digit; thus a 3-by-5 array is available to represent all digits. The motion of the recording paper from reel to reel during the printing process is continuous at speeds which may be varied to suit the information input rate. When recording 500 3-digit numbers per second,