What year did ben Franklin sign the declaration of independence?

It was signed in 1776 (although several signatures were added later than the others).

The Declaration of Independence is an open letter to George III, explaining why the American colonies considered themselves free from British rule. It was written by Thomas Jefferson between June 11 and June 28, 1776, with changes suggested by others including Benjamin Franklin and John Adams. It was adopted by the Continental Congress on July 4, 1776.