You could try your HP DeskJet 845C printer with the printer drivers from GutenPrint:
http://tinyurl.com/8ctlaw. You'll also want to download the high end USB backend for GutenPrint known as Usbtb:
http://tinyurl.com/9mgm38. It should make your printer print much faster than it currently does since its superior to Leopard's built-in USB driver.
You'll also want GNU Ghostscript 8.61 for faster rasterizing of the pages before they actually get printed:
http://tinyurl.com/4cwqlt. You'll also want to install HPIJS which is HP's Open Source driver for their printers when run under Unix or Unix-like OSes such as Leopard (Mac OS X 10.5.6):
http://tinyurl.com/ayhp9z. You'll also need Foomatic-RIP which if I understand it correctly is a Open Source print spooler for Unix or Unix-like OSes such as Leopard:
http://tinyurl.com/4ep5dv.
Once you have all the required software installed your printer should run/print faster & you should have more print options available like before. Unfortunately the drivers built into Leopard pale in comparison to the Open Source software offerings I just mentioned.