Photography – Camera detail – Detachable or removable film holder unit
Reexamination Certificate
1999-08-06
2001-02-06
Rutledge, D. (Department: 2851)
Photography
Camera detail
Detachable or removable film holder unit
C396S583000, C396S527000
Reexamination Certificate
active
06183144
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an instant photo film pack. More particularly, the present invention relates to an instant photo film pack in which an outlet slit can be shielded reliably from ambient light.
2. Description Related to the Prior Art
An instant photo film pack for use with an instant camera is known in the field of photosensitive material. JP-A 7-209814 discloses an example of the photo film pack, which is constituted by a pack case of hard plastic shaped as a box, and contains self-processing photo film units of a mono-sheet type. Each of the photo film units includes an exposure portion of a photosensitive sheet, a solution pod and a trap portion. The exposure portion includes a photosensitive layer and a light receiving layer. The solution pod encloses processing solution. The trap portion traps and hardens the surplus part of the processing solution.
There are an exposure opening and an outlet slit in the case of the photo film pack. The outlet slit is formed for exiting of each exposed one of the photo film units. A light-shielding cover sheet of hard plastics is laid on an exposure surface of a first one of the photo film units, and closes the exposure opening to avoid entry of light.
The photo film pack is inserted into a photo film loading chamber of the instant camera. A shutter release button of the instant camera is depressed to take an exposure. In response to this, a claw mechanism, incorporated in the body of the instant camera as well-known in the art, pushes only the exposed one of the photo film units and ejects it through the outlet slit of the photo film pack. The photo film unit is nipped by a set of spreader rollers, and advanced toward a camera outlet of the instant camera. The spreader roller set spreads processing solution on an exposure surface of the photo film unit to develop the photo film unit. At the same time, a succeeding one of the photo film units is shifted forwards and becomes set on the exposure opening.
There is a light-shielding flap or thin sheet of resin attached to the outlet slit of the photo film pack for avoiding entry of ambient light into the photo film pack and fogging of an unexposed one of the photo film units. For attaching the light-shielding flap, adhesive agent is used, an example of which is a hot-melt type for the reason of productivity of the photo film pack.
The light-shielding flap of the prior art is attached by use of a simply straight region of adhesion to the outlet slit of the photo film pack. As the temperature changes from high temperature of hot-melt adhesion to low temperature, wrinkles or shrinkage in the light-shielding flap is likely to occur at the outlet slit. A space or gap may be created with the outlet slit typically at an end of the light-shielding flap. Ambient light may enter through the space of the gap to fog or expose the photo film units.
SUMMARY OF THE INVENTION
In view of the foregoing problems, an object of the present invention is to provide an instant photo film pack in which photo film units can be reliably prevented from being fogged or exposed by ambient light.
In order to achieve the above and other objects and advantages of this invention, an instant photo film pack includes a pack case for containing a stack of plural self-processing photo film units. An outlet slit is formed in the pack case, for exiting an exposed one of the photo film units therethrough. A light-shielding flap has a substantially quadrilateral shape, for closing the outlet slit in a light-tight manner, the light-shielding flap having first, second and third predetermined adhering regions, at least the first, second and third adhering regions being coated with adhesive agent and attached to the pack case. The light-shielding flap has first and second longer side lines and first and second shorter side lines. The first adhering region has a linear shape and extends along the first longer side line. The second and third adhering regions have a dot shape, and are disposed respectively at the first and second shorter side lines, the outlet slit being disposed between the second and third adhering regions.
According to another aspect of the present invention, a light-shielding flap has a predetermined adhering region, at least the adhering region being coated with adhesive agent and attached to the pack case, the light-shielding flap having first and second longer side lines and first and second shorter side lines. The adhering region includes a linear portion disposed to extend along a first longer side line. First and second lateral portions are disposed to extend from ends of the linear portion and along the first and second shorter side lines, the outlet slit being disposed between the first and second lateral portions.
The adhesive agent is hot-melt adhesive agent. The light-shielding flap is attached to the pack case by application of heat to the adhering region.
The first and second lateral portions extend to the second longer side line.
In another preferred embodiment, the first and second lateral portions are disposed away from the second longer side line.
The light-shielding flap is obtained by cutting continuous sheet material coated with the hot-melt adhesive agent at a predetermined size.
The adhering region is pre-coated in a patterned manner with the hot-melt adhesive agent.
In another preferred embodiment, a coating pattern is pre-coated with the hot-melt adhesive agent, and the adhering region is a portion of the coating pattern.
The light-shielding flap is plastic.
According to still another aspect of the present invention, the photo film units include an exposure portion disposed substantially at a center, a processing solution pod, disposed along one of edges, for containing processing solution, and a trap portion, disposed one of the edges opposite to the solution pod with reference to the exposure portion, for trapping and hardening a surplus part of the processing solution spread on the exposure portion. Furthermore, an exposure opening is formed in the pack case, for providing the photo film units with an exposure. First and second support ridges are disposed on an inner wall of the pack case opposite to the exposure opening, extend substantially in parallel with each other, and have a support edge convexly curved at least partially, the support edge contacting a rear of the stack of the photo film units, for positioning the stack on the exposure opening. The support edge includes a first section disposed behind the exposure portion. A second section is disposed behind the solution pod, and curved convexly toward the exposure opening. A third section is disposed behind the trap portion to protrude toward the exposure opening beyond the second section, for preventing one of the photo film units being exited.
The second and third sections satisfy:
R
2
<R
1
where R
1
is a radius of the second section, and R
2
is a radius of the third section.
The first section is straight.
The exposure portion is substantially quadrilateral, and the solution pod and the trap portion are disposed along shorter side lines of the exposure portion.
The exposure portion is substantially quadrilateral, and the solution pod and the trap portion are disposed along longer side lines of the exposure portion.
According to another aspect of the present invention, an instant photo film pack includes a pack case for containing a stack of plural self-processing photo film units, the pack case having first and second walls disposed in front of and behind the photo film units. An exposure opening is formed in the first wall, for providing a first one of the photo film units with an exposure therethrough. An outlet slit is formed in an end wall of the pack case, extended substantially in parallel with one side line of the exposure opening, for exiting exposed the first photo film unit therethrough. First and second shifting projections are disposed between the exposure opening and the outlet slit to project from an inner face of the first wall, positioned close
Hatakeyama Koichi
Mizuno Kazunori
Sugiyama Nobuo
Takahashi Tomoyuki
Takatori Tetsuya
Fuji Photo Film Co. , Ltd.
Rutledge D.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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