I see, then this means some foreign object is stuck in the paper feed or printer, or the paper sensor in the ADF feed tray has become dirty or defective, please take these steps:
Unplug the printer sharply from the power outlet while it is still on
Remove all paper from the paper feed and blow it out with compressed air a few times (This step is very important, if you don't have compressed air on hand you can get one from a local electronic/computer store for a few dollars)
With a flashlight look in the ADF paper feed > Make sure there is no foreign object like a paper clip, also look for jammed paper > Also look in the regular feed and blow some compressed air inside the printer as well to remove excess dust > Next take a q-tip moistened with bottle water and clean the feed rollers off.
While the printer is still off, press and hold the power button for 3 minutes > Load 1 sheet of paper into the paper tray
Finally, while holding down the stop/cancel button (or just the power button if you don't have those), plug the printer back in, and power on the printer if it doesn't do so automatically, then try a test page (click below to view):
Press the Menu button repeatedly until Maintenance appears.
Use the the left or right arrow button to select Nozzle check, and press the OK button.
The nozzle check pattern should print out. However if the nozzle test does not print and you get the same error, then the printer will need to be taken apart and the sensors inside may need to be replaced. Unfortunately, if the warranty is out, it may be more cost effective to buy a new printer, but you may certainly call 1-800-463-7766 first to get a quote for the repairs and make a final decision.