Abstract: A sensor for sensing and identifying characteristics of a printer ink ribbon when a ribbon supply roll is inserted into a printer and operated. Ink ribbon cartridges used in printers are provided in a number of types, colors, and other identifiable characteristics that are important for insuring that the correct ribbon is inserted in the printer for the then current print job. In the present invention, the ribbon cartridges include ribbon supply rolls which are provided with identifying indicia on one end of the roll, and a sensor to read the presence of indicia when the printer is operated. The positions of the indicia relative to selected reference positions indicates the ink ribbon type. Suitable circuitry is used to disable the printer if the print ribbon is not properly correlated to the requirements of the printer.

Abstract: A printer providing time coded heating energy applications to printhead resistors to provide variable volmetric densities. Variable densities can also be provided through integrating dithering with the varying of volumetric densities. The printer can provide either one of two kinds of printing technologies by selection.

Abstract: An arrangement for acquiring signal representatives intended to correspond to character representations, out of a set of possible character representations, provided on a substrate that emanate magnetic fields which can be sensed to provide a related waveform. Times of extrema of the waveform are ordered and compared with the ordering of time locations in waveforms expected for the set of possible characters with different orderings being used to eliminate those possible characters having expected waveforms incompatible with the extrema ordered times of the measured waveform.

Abstract: A video display control system with a relative position memory between a controller and a foreground memory to permit changing the correspondence between a control indicator, indicating a display line on a monitor, and that one of the blocks of foreground memory controlling the foreground characters to be displayed on that display monitor screen line. The controller indicator signal is provided directly to a background memory to indicate which block of data therein is to control the display for the graphics background on that screen line. The relative position memory circuit also sets the first column in a test line which is to display in an allocated portion of the monitor screen. The relative position memory and the foreground memory control a symbol memory, and the outputs from the foreground memory, the symbol memory and the background memory are collected by a display controller capable of operating a display monitor.