Positioning mechanism and positioning mechanism for film scanner

1. A positioning mechanism comprising:

a moving body configured to move by receiving a drive force supplied from a drive source;

a stopper which defines a movement extremity of the moving body; and

a biasing device configured to engage the moving body when the moving body is moved to a vicinity of the movement extremity, and upon engagement with the moving body, said biasing device is configured to convert the force from the moving body into a force to bias the moving body toward the stopper.

2. The positioning mechanism according to claim 1 , wherein the biasing device comprises:

a toothed cam configured to engage a rack provided on the moving body when the moving body is moved to the vicinity of a movement extremity of the moving body, said toothed cam rotatably supported at a predetermined position; and

a biasing member in elastic contact with the toothed cam, said toothed cam biased by the biasing member to rotate in a direction so that the moving body abuts against the stopper when the moving body is moved to the vicinity of said movement extremity such that the toothed cam begins engaging the rack.

3. A positioning mechanism comprising:

a driving body configured to move by receiving a drive force supplied from a drive source;

a driven body configured to receive moving force from the driving body and moves in the same direction as the driving body;

a stopper which defines a movement extremity of the driven body; and

a biasing device configured to convert the moving force from the driving body after the driven body abuts against the stopper, into a force to bias the driven body toward the stopper to bias the driven body.

4. The positioning mechanism according to claim 3 , wherein the biasing device comprises a compression spring provided between the driving body and the driven body and which is compressed when the driving body is moved to thereby transmit the movement of the driving body to the driven body.

5. A positioning mechanism for a film scanner having a light source, an illumination optical system configured to change a light bundle emitted from the light source to correspond to the size of a film and illuminates a surface of the film, and an image pickup optical system configured to change the light bundle transmitted through the film surface to correspond to an area of an image pickup element to be used wherein the light bundle is incident upon the image pickup element, said positioning mechanism comprising:

a moving body configured to hold a movable lens which constitutes a portion of one of the illumination optical system and the image pickup optical system, said moving body configured to be moved by receiving a drive force supplied from a drive source along an optical axis direction of said one of the illumination optical system and the image pickup optical system;

a stopper in contact with the moving body to define a movement extremity of the moving body; and

a biasing device configured to engage with the moving body when the moving body is moved to a vicinity of the movement extremity, and upon engagement with the moving body, said biasing device is configured to convert the force from the moving body into a force to bias the moving body toward the stopper.

6. The positioning mechanism for a film scanner according to claim 5 , wherein the biasing device comprises a toothed cam configured to engage a rack provided on the moving body when the moving body is moved to the vicinity of the movement extremity, and configured to is rotatably supported at a predetermined position; and a biasing member configured to is in elastic contact with the toothed cam, said toothed cam being biased by the biasing member to rotate in a direction to bring the moving body in contact with the stopper when the moving body is moved to the vicinity of the movement extremity such that the toothed cam begins engaging with the rack.

7. A positioning mechanism for a film scanner having a light source, an illumination optical system configured to change the width of light bundle emitted from the light source to correspond to the size of a film and illuminates a surface of the film, and an image pickup optical system configured to change the light bundle transmitted through the film surface to correspond to an area of an image pickup element to be used, wherein the light bundle is incident upon the image pickup element, said positioning mechanism comprising:

a driving body configured to move by receiving a drive force supplied from a drive source, along an optical axis of one of the illumination optical system and the image pickup optical system;

a driven body configured to receive the moving force from the driving body and moves in the same direction as the driving body, said driven body supporting a movable lens which constitutes a portion of said one of the illumination optical system and the image pickup optical system;

a stopper which defines a movement extremity of the driven body; and

a biasing device configured to convert the moving force from the driving body, after the driven body abuts against the stopper, into a force to bias the driven body toward the stopper to thereby bias the driven body.

8. The positioning mechanism for a film scanner according to claim 7 , wherein the biasing device comprises a compression spring provided between the driving body and the driven body, and said spring configured to be compressed when the driving body is moved, to transmit the movement of the driving body to the driven body.