Doubling Thermal Printer Resolution by Wiggling

Insides of the Sears 12 calculator. (Credit: Danalog, YouTube) Thermal printers are still extremely common today, using small heating elements in combination with temperature-sensitive paper to create a dot matrix-like effect without messing with ink ribbons and complex mechanisms. Of course, even with just a line of elements you still needed one of these per pixel, which at least in the 1970s when the Sears 12 calculator was released added significantly to the cost.