DIAGNOSIS That's almost always the print head carriage hitting something or moving on a dry track. A piece of debris (like a fallen paper clip) or dried-out grease on the carriage rail are the prime suspects.
FIX Power off and unplug the printer. Open the front cover. Manually slide the print head carriage all the way across its rail. Look and feel for any obstructions. If clear, put a small drop of plain white lithium grease on a cotton swab and apply a very thin coat to the shiny metal rod the carriage slides on. Slide the carriage back and forth a few times to distribute it.
IF THAT DIDN'T WORK A more serious mechanical failure could be happening inside the gear train. If the noise is a rapid clicking from the right side near the paper feed, it might be a worn gear. At that point, a service repair is needed.
HEADS UP Never use oil (like WD-40) on the carriage rod, only a tiny amount of grease designed for plastics and metals. Oil will attract more dust and eventually make the problem worse.