[cups] only one machine won't print

[hymie!]

Greetings.  I hope somebody can help me.  I'm really at my wits' end.

I have a mixed environment at home, 2 Slackware Linux machines and a Windows
8 machine, and a networked Brother MFC-J630W.

For the longest time, everything worked great.  Not too long ago, one (and
just one) of the Linux machines stopped printing.  I've checked a bunch of
things, too many to list, and I don't know where the problem is or what I
did to cause it.

I started with this error

Unsupported format "application/vnd.cups-banner".

which led me to this thread

http://comments.gmane.org/gmane.comp.printing.cups.general/28098

which led me to this comment:

   What you'll need to do is set the LogLevel to debug2 with:

	cupsctl LogLevel=debug2

   and then run:

	grep add_printer_filter /var/log/cups/error_log

   I'm guessing that the drivers you are using are specifying filters that do
   not exist...

I ran this command and got

d [19/Jan/2016:14:01:15 -0500] add_printer_filter(p=0xb787b198(J630W),
filtertype=0xb787b7d8(printer/J630W), filter="application/vnd.cups-raw
application/octet-stream 0 -")
d [19/Jan/2016:14:01:15 -0500] add_printer_filter: J630W: adding filter
application/vnd.cups-raw printer/J630W/application/octet-stream 0 -
d [19/Jan/2016:14:01:15 -0500] add_printer_filter: J630W: adding filter
printer/J630W/application/octet-stream printer/J630W 0 -
d [19/Jan/2016:14:01:15 -0500] add_printer_filter(p=0xb787b198(J630W),
filtertype=0xb787b7d8(printer/J630W),
filter="application/vnd.cups-postscript 0 brlpdwrappermfcj630w")
d [19/Jan/2016:14:01:15 -0500] add_printer_filter: J630W: adding filter
application/vnd.cups-postscript printer/J630W 0 brlpdwrappermfcj630w
d [19/Jan/2016:14:01:15 -0500] add_printer_filter(p=0xb787b198(J630W),
filtertype=0xb787b7d8(printer/J630W), filter="application/vnd.cups-command
application/postscript 100 commandtops")
d [19/Jan/2016:14:01:15 -0500] add_printer_filter: J630W: adding filter
application/vnd.cups-command printer/J630W/application/postscript 100
commandtops
d [19/Jan/2016:14:01:15 -0500] add_printer_filter: J630W: adding filter
printer/J630W/application/postscript printer/J630W 0 -

(which means nothing to me).  Then I found this page:

http://www.bsmdevelopment.com/Reference/Tech_20130002.html

which suggested I replace the /usr/share/cups/data/testprint file.  So I no
longer get the cups-banner error, but I'm still not getting anything out of
my printer.  Every job appears to end in this state:

J630W-257  	Test Page  	anonymous  	17k  	Unknown     completed at
Tue 19 Jan 2016 01:56:17 PM EST 
"No pages found!"

Tax season is coming up, and I'd really like to print my tax forms. :)  If
there's any troubleshooting that somebody can point me to, I'd really
appreciate it.

--hymie!