Yes, it is very likely that the ImageWriter LQ is overheating. There is a
temperature sensor in the printhead that causes the printer to stop printing
when the printhead temperature reaches approximately 190 degrees Fahrenheit.
The ImageWriter LQ printhead reaches this temperature after printing pure black
for about 1 hour. Depending on the text being printed, the printhead may
overheat after approximately 2 to 6 hours of continuous printing.