Self-developing photo film unit with trap member for trapping surplus developing solution

摘要

A self-developing photo film unit has a photosensitive sheet, first and second spacer rail members, a cover sheet, a mask sheet, a developing solution pod, and a strip-shaped trap member. The mask sheet has a mask portion, first and second bendback edge portions defined by being bent along first and second bend lines, and an aperture. The developing solution pod contains developing solution and is squeezed and enclosed between the first bendback edge portion and the mask portion. After the photosensitive sheet is exposed, the developing solution is spread from the developing solution pod between the photosensitive sheet and the cover sheet while being regulated between the first and second spacer rail members. The trap member is squeezed and enclosed between the second bendback edge portion and the mask portion, and captures a surplus part of the developing solution after the developing solution is spread. In the self-developing photo film unit, the trap member includes non-woven fabric having a porosity of 70% or more, including acid polymer impregnated therein, and having a first surface opposed to the second bendback edge portion, and a second surface having less acid polymer impregnated than the first surface. A securing region is disposed along one of two longer side lines of the trap member nearer to the aperture, and coated with adhesive agent, for securing the trap member to the second bendback edge portion.