printing errors HELP! unable to send printer command!

Yes, I've deleted the printers (connected through USB), also reset printing system, deleted the printer folders in library/printers/hp (and Epson) shut down and restarted my computer...reinstalled both printers via apple update for the drivers and nothing. I 've done this a few times, I can't even print a test page now.

I tried seting up AirPrint so I could print from an iPhone and iPad through the home Wi-Fi network. I think I messed that up, too.

I'm not worried about the Airprint at the moment, that's another issues, (and you're probably right, i don't think the network is set up correctly), my real concern is that I can't print from my iMac to either printer, (attached USB) I could a few days ago. My iMac recognizes the printers but won't print, I get the error message- "Unable to send printer command! Unsupported document-format "application/vnd.cups-command". I am able to scan to the iMac from the Epson (I know it's not airprint capable, the HP is). If I unplug the printer(s) it says they're offline, when I plug them in it says they're online but when I try to print something/anything to either one, nothing happens, well, if I look at the (printer) jobs list, it says under staus, "deleted". I appreaciate your help.

Thank you for your help. I've tried deleting the printers and cache- I get nothing except my original error messages. "Unable to send printer command! 'Unsupported document-format' application/vnd.cups-command" and when I go to the jobs list I can see the job I sent to the printer. Nothing prints and it says it was deleted.

The weird thing is, when I'm in Parallels, Windows programs on the mac I can print. Everything seems to working ok in Parallels. Not sure what I should do now. Saw some posts about CUPS printing issues.Could something there be my problem? Should I try to "go back" in time machine to when the printers worked? Maybe reinstall/recover something?

I've added the printers, (connected USB directly to the mac), through system preferences, print & scan..., then updated through software update. They load fine-green lights on both printers-

Still can't print from any app...but now, after downloading gutenprint 5.2.8-pre1 driver (because I'm desperate) the Epson spit out a self test page but I still can't print a test page, status says deleted. I can actually watch it pop up in the jobs completed list.

What am I missing?!!!

It's all working!!!!! I needed to reinstall the CUPS driver, I must have screwed that up somehow, now it all works. As for the Airprint, I just needed to turn off the firewall. We can now print from our iPhones, iPads, Macbooks!!