Patent ID: 6318861
Filing Date: 2001-11-20
Classification: G03B,H04N

Abstract:
A film positioning system for feeding a film in a forward direction and then stopping it at a predetermined stop position, comprising:first feeding means engaged with said film on a supplied side, for pulling the above film in said forward direction by a prescribed distance to send said film to said stop position;second feeding means engaged with said film on a supplying side to the forward direction of said film, for feeding said film in said forward direction by the prescribed distance and synchronizing with said first feeding means to send said film to said stop positions; andcontrol means for making said first feeding means or said second feeding means hold said film at said stop position when said film is stopped at said stop position, and for making the other of said first feeding means or said second feeding means apply a fixed tension to said film when said one of the first feeding means or the second feeding means holds said film at said stop position;wherein:said fixed tension is applied to said film by said control means by commanding a reverse direction force on said film by the other of said first feeding means or said second feeding means;said first feeding means and second feeding means are controlled by said control means when feeding said film in a forward direction;said control means controls said first feeding means and said second feeding means in said forward direction by,recognizing a current position of said film,generating a driving pulse that signals movement of said film by said control means,calculating a control value that accounts for error in the current position of said film compared to a target position of said film,driving said film according to the driving pulse and said control value, andrepeating said steps of recognizing, generating, calculating, and driving until a new target position is reached; andsaid control value comprises a calculation including a derivative and integral of a difference ""e"" between a present position of said film and the target position of said film.