https://whatis.techtarget.com/definition/EMF-Enhanced-MetaFile
"A raw spool file is a one that is sent to the Windows spooler unprocessed
(which is why it's called "raw"). The raw file is used to send
Postscript commands to a Postscript printer. The Postscript commands are
understood by the printer, but are just plain data to the Windows spooler.
The raw format is device-dependent and slower.
"
Maybe the raw mode on a HL1450 is a PCL6 stream.
Whereas a raw mode to a Selectric 300 baud device, would
be some kind of extended ASCII stream (characters).
The raw mode then, is a bypass of some spooler processing step.
One of the reasons for "print to file", was presumably so you
could later "send in RAW mode to a printing device" and
the stream would be considered to be ready to go. That's
why if you look at how the stupid spooler saves PostScript output
when printing to file, the output is "wrapped" in printer
control language. The printer control strings would presumably
put the printer in the correct mode, if the file was streamed
directly to the printer. Not a lot of people do things
that way.
*******
I'm finding there are two ways to send a print. EMF and RAW.
This web page, shows the bypassing of the print driver, so
that you can inject a RAW file (created by Print to File and
already has directives on head and tail). The RAW file still
sits in the Spool dialog (monitor) for the printer, and clicking
it and doing properties, if sent by this program, would be
marked as being RAW. Whereas print jobs having gone through
the print driver have Properties of EMF (Enhanced Meta Format).
https://www.compuphase.com/software_spool.htm
Maybe something like this (still not helpful for solving your problem).
GDI --- print driver ----- (EMF) --------------
\___ Windows Spooler ___ Printer
/
(file) -- discrete-spool-dumper --- (RAW) ---
The print as black, might refer to impact printing devices of
long ago, which could output characters if fed an ASCII file.
(Equivalent to generating a 7x9 matrix pattern if fed a single
8 bit byte of ASCII.) A modern device could certainly have
such modes (because the printer has its own powerful processor),
but the printer does not have the "tradition" of doing so.
Most customers would use the bloated OS print path for
accessing a printer, and would not be sending "line printer output"
directly as an ASCII stream. This is probably why the setting
is "missing" from your kit - the printer is too good, to be
doing that. Only formatted output accepted (PCL6, PostScript),
both of which use the printer processor as the interpreter that
generates the pixmap or halftone representation (color approximations
via dot density).
*******
The question would be, is there a means for some "evil" piece
of software on your machine, to be doing what the Compuphase
demo program is doing, namely bypassing the normal print path
and sending a RAW representation to the Windows Spooler. Somehow,
this means calling the Windows Spooler in RAW mode, and sending
some crap. I wonder if there is some inline sequence (in a shell)
that can be sent, which Windows traps and treats as a print job ?
The problem may be, that when the Windows Spooler says to the
printer "Here comes a RAW print job", the printer would say
"Hey, I don't support this mode, whatever you're trying to do".
It would then be your job as print administrator, to figure out
how the spooler ended up compromised like this. And how it's
possible for a RAW job to be dumped there.
The Google result, suggests some older print driver, when
that "print as Black" setting is selected, they could be
emitting RAW into the Windows Spooler, in place of EMF.
Your printer driver won't be doing that (no tick box),
if your printer doesn't have or support a RAW mode. But
if the RAW can get in there some other way, that could
cause an error result. Like using the Compuphase program,
could result in the same kind of error and stuck-in-queue
condition.
Paul