Following Rajat's post, I decided to dig deeper into this printer support issue for the LJ Pro m1212nf printer.
Again, I scanned backwards and forwards through the Oct. 2012 Apple update, HP Printer Drivers v2.12 for OS X, and did not find the m1212nf printer in the list of currently supported printers for Mountain Lion. Just in case I missed it the first and second time through.
The software that Rajat suggests is universal binary (PPC/Intel) that was released in early June 2012 and was for OX 10.6 and OS X 10.7 support. There is no indication that HP tested it against Mountain Lion, and in fact, despite what HP says below, the printer no longer appears supported in Mountain Lion per HP documentation below.
HP suggests that if this printer was installed and working with Snow Leopard or Lion, that during the upgrade process to Mountain Lion, the driver would be automatically updated and the printer would work with Mountain Lion too. Yet, by October 2012, there is no explicit HP driver support for the m1212nf printer on their site, or through HP printer updates supplied via Apple, for Mountain Lion. No doubt, there is temptation to install the old driver support. If it causes your system to crash dump, uninstalling it will be a PITA.
See this link, “Installing the printer on a Mac running OS X 10.8 Mountain Lion (Network Connections Only). On that page, there is an expandable section entitled, “Is my printer supported in OS X 10.8 Mountain Lion.” When expanded, it produces another link to HP Printers supported in Mac OS X 10.6, OS X 10.7, and OS X 10.8. On that page, expand the category, HP LaserJet color printers and All-In-Ones. Even though you are presently on an HP Customer Care page for the M1212nf printer, HP indicates that this printer is not among the supported printers in Mountain Lion. In fact, support begins with the M1217mfw series!
The best metaphor for HP these days is a dyslexic dog chasing its tail.
I haven't changed my position. Originally, I could have sent you a link to the same outdated driver download, without all this extra investigation. I felt you deserved better, factual guidance.
I still use an HP Laserjet 4M Plus that I purchased new in 1994. Cost $2400. Still driver support for it in Mountain Lion. Still no problems with the printer. It was made for HP by Canon. When it is time to replace this printer, HP will not make the short list.