Sign permit required. Except as otherwise provided herein, it shall be unlawful for any person to erect, construct, enlarge, move or convert any sign in the Town, or cause the same to be done, without first obtaining a sign permit for each such sign. These directives shall not be construed to require any permit for a change of copy of any sign, provided that the person, place, establishment, business or service identified remains the same, nor for the repainting, cleaning and the normal maintenance or repair of a sign or sign structure for which a permit has previously been issued under this article, so long as the sign or sign structure is not modified in any way.