Abstract: An electronic apparatus having a keyboard and an output device, such as a thermal printer unit. The apparatus, including its printer unit, is burn-in tested by an electronic system built into the apparatus. The system includes a memory, a circuit for storing a preselected or predetermined alphanumeric code in the memory and a circuit for repetitively causing the printer unit to print the contents of the memory. A delay system may be incorporated which causes the apparatus to enter a wait mode between printing operations. The period of time that the system is in the wait mode may be either a fixed duration or of a selected duration. In the embodiment disclosed, the apparatus is an electronic calculator.

Abstract: Described is a printer mechanism which includes a platen rotatably mounted above a base, a medium upon which printing is to be accomplished and a printer unit disposed in printing relationship to the medium and the platen. A holder holds the printer unit and includes a ball and socket assembly for permitting the holder and printer to pivot about first and second orthogonal axes with respect to the platen. The holder also includes a projection which projects into a channel for inhibiting the holder and the printer unit from pivoting about a third axis, the third axis being orthoganol to both a first and second axes. The channel and an end of the ball and socket assembly are attached to the base. The printer unit is preferably of a non-inpact type such as a thermal printer unit which is mounted on a ceramic substrate for instance. The holder is urged toward the platen by means of a spring, which is attached to the holder and to the base.