Abstract: A printhead of a resistive ribbon printer has a column of electrodes formed on each of at least two edge surfaces. When the column of electrodes at one edge surface is worn out after being used for printing, the printhead is rotated so that the column of electrodes at the other edge surface is used for printing. Instead of the column of electrodes at each edge surface being the same size, the column of electrodes at one edge surface could be smaller than at the other edge surface so as to have a higher resolution for graphics whereby the position of the printhead is changed each time that higher resolution is desired and then returned to its initial position when alphanumeric printing is to occur. The printhead could have more than two edge surfaces with each having a column of electrodes for printing when at the printing position.

Abstract: It has been discovered for the practice of this disclosure that there is a threshold for switching with light an AC coupled electroluminescence (EL) device within the .DELTA.V of the luminance-voltage hysteresis loop thereof. Practice of this disclosure provides hybrid matrix-addressing of an electroluminescence display device with memory through luminance-voltage hysteresis by "ANDING" electrical and optical signals. It has particular utility for a large aspect ratio display, e.g., a single line display, i.e., one for which there is more information content in one direction than in another direction.

Abstract: A blue color AC gas discharge display panel is obtained by the room-temperature Hg vapor seeding of high pressure Ar gas as the luminous gas mixture. Typically, the panel uses room-temperature Hg (approximately 3m Torr) in several hundred Torr of argon. Generally, good resolution is achieved in standard AC panels in at least 300 Torr. The upper limit is nominally one atmosphere. This gives an Hg seeding of less than 0.001% of the total gas pressure. Thus, direct electron excitation of Hg atoms is negligible and the discharge condition involves only the excitation of argon atoms by the electrons.