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That sounds like a problem with a Brother printer, at a guess... but let me know the maker and model # *****
You may have a stuck or broken sensor switch on your printer's paper output cover. (The cover to the output paper area, is what that is.) Locating the paper output cover sensor switch, and seeing whether it is jammed or broken, might help, though it is likely to be an invisible defect.
How old is the printer? if less than 1 year from purchase date, the repair (-f repair is needed, and that is unfortunately rather likely) would be free of charge under warranty.