Canon Pixma iP1500 Troubles

Hey gang and thank you for your time,

I had this great little printer that I got on CL for $20 and the 3rd party ink for it is very cheap online. I have the Canon Pixma iP1500. It has been working fine up until very recently when it just stopped working correctly. It appears that when I'm printing in black (colors work ok, but more costly to print everything dark-brown) I get missing lines on the page. It looks like it's not printing when the head returns over the paper each pass.

I've tries this so far:
Re-install drivers
Clean printer head
Cleaned nozzles
Replaced black ink cartridge
Removed color cartridge

Any other ideas what's going on here? I have a link to a picture of the default MS Windows test page. It's crappy quality, but you can see what I'm talking about. Oh, and the apparent smudging/streaking on the right-side of the page is just ink bleeding through the other side.

Thanks again for any advice,
David