There are several synonyms that can be used to describe the phrase "his eye fell on a misprint." For instance, one could say "he noticed a typographical error," "he stumbled upon a print mistake," or "he spotted an error in the text." Alternatively, one could use the phrase "his attention was drawn to an error in the text" or "he became aware of a misprint as he was reading." Regardless of the phrasing used, it is clear that the individual in question noticed an error in the text and was likely compelled to correct it or bring it to someone's attention.