Hi guys, the solution to all your problems (I have the same printer) is:
1. Go to system preferences, printers & scanners
2. Delete the current Laserjet 2100 printer using the minus sign below the list of printers
3. Use the plus sign to add the printer again but this time:
4. Name the printer what you like, location as well or leave that blank
5. In the "Use" field, choose "Generic PCL Printer"
whats going on is:
- the HP driver is only valid for OS X 10.7 as the latest os it supports
- the driver does default to PostScript level 2 which is what the printer has
- mavericks is attempting to send the printer postscript level 3 which the printer can't understand, the printer is too old 😟
- I can't find a way of forcing mavericks to use postscript level 2, even if choosing the "Generic Postscript Printer" driver
LImitations of the generic PCL driver is that you can only get it to do a max of 600 DPI, so graphics will look yuck if you're used to 1200DPI.