In the event of a printing stall, and occasionally during normal operation, the fusing oven would cause the paper to combust.
The line printer employed a series of status codes, specifically ready, online, and check.
[2] In the early 1980s, Xerox created a prototype laser printer engine and provided units to various computer companies.
Michael K. Johnson ("mkj" of Red Hat and Fedora fame) wrote the first Linux version of this error message in 1992.
[5][6] Since then, the lp printer code has spread across all sorts of POSIX-compliant operating systems, which often still retain this legacy message.