To reduce the thickness of an instant film with a small image plane size.
In the film unit 13, a photosensitive sheet 21 and a cover sheet 26 are joined to a mask sheet 20 in which an opening 20a corresponding to a positive image transfer range has been made in such a way as to cover the opening 20a. One end and the other end of the mask sheet 20 protrudent from the photosensitive sheet 21 are folded back and a pod material 24 and a trap material 25 are sealed in the folded ends. After exposing the photosensitive sheet 21, a developing solution is discharged from the pod material 24 and spread between the photosensitive sheet 21 and the cover sheet 26 to transfer a latent image formed on an image receiving surface of the photosensitive sheet 21 to an image forming surface as a positive image. The film unit 13 is formed in such a size as to adjust the area ratio of the opening 20a to a margin exclusive of the opening 20a and housing the pod material 24, the trap material 25, etc., to ≤1.2, preferably ≤1.3.
TAKATORI TETSUYA
KOBAYASHI NORIFUMI
ISHII SHINICHI
MARUYAMA ATSUSHI
