I found a troubleshooting article for printers attached by USB cable that matches your operating system.
I would follow the below steps to see if that resolves the issue:
Follow these steps until the issue is addressed:
- Make sure that the printer is powered on, has ink / toner, and that there are no alerts on the printer’s control panel. Note: If you cannot clear an alert on the printer's control panel, stop here and check the printer's documentation or contact the manufacturer for support.
- Ensure the printer is properly connected to a USB port on the Mac or AirPort base station / Time Capsule. If the printer is a network-capable printer, make sure that it is properly connected to your home network.
- Use Software Update to find and install the latest available updates. If an update is installed, see if the issue persists.
- Open the Print & Scan pane (OS X Lion) or Print & Fax (Snow Leopard) pane in System Preferences.
- Delete the affected printer, then add the printer again.
If the issue persists, try these additional steps:
- Reset the printing system, then add the printer again.
- If the issue still persists, reset the printing system again. Download and install your printer's drivers from here. Then, add the printer again.
- Contact the printer vendor or visit their website for further assistance.
Thanks for the tips, but I've already tried those things several times, and nothing worked. Also, I posted a message on the HP forums, but it's been several days and no one has repsonded. Sigh.
I have two identical 2100M printers. I've experimented with every possible printer/cable/port configuration. If I print wirelessly (using Airport Express), all is well. If I use the same printer and the same USB cable and plug the cable into the USB port on my Mac, I get problems. So, somehow the problem has to do with the USB ports. I think the USB ports are fine, because every other periphal I have works fine with the USB port. It's just that now my Mac doesn't like communicating with the printer via USB port.
Any other ideas? Perhaps this is an OS issue?