JP2000081688A - Instant film pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flatness of an exposure surface at the time of setting a film unit at an exposure aperture from being deteriorated due to the inclination of the film unit caused when it is preserved in a film pack over a long term. SOLUTION: Plural film units are housed inside the film pack. Nearly circular-arc-shaped straightening ribs 25 for straightening the inclination of the film unit are respectively formed on the internal walls of two sides in parallel with the ejection direction of the film unit out of four constituting sides in the exposure aperture 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instant film pack used in an instant camera or the like and containing a plurality of self-developing film units therein.

[0002]

2. Description of the Related Art Instant film packs (hereinafter referred to as "instant film packs")
The “film pack” is disclosed in, for example,
As described in JP-A-9814, a plurality of rectangular mono-sheet type self-developing film units (hereinafter referred to as film units) are provided in a box-shaped plastic light-shielding container (hard case). It is stored in a stack.

[0003] The film pack is provided with an exposure opening for allowing subject light to enter the exposure surface of the film unit when the film pack is loaded in a camera. This exposure aperture is
Usually, light is shielded by a light-shielding cover placed on the uppermost layer of the film unit. The light-shielding cover and the exposed film unit are discharged by a claw member on the camera side from a discharge port provided on a surface orthogonal to the surface provided with the exposure opening. A hole is formed on the surface of the film pack facing the exposure opening. The hole is normally shielded from light by an elastic light-shielding sheet provided on the film pack. When the hole is loaded into the camera, a push-up member provided on the back cover of the camera enters the hole. The push-up member pushes the film unit from the lowermost layer to the exposure opening via the light-shielding sheet, discharges the photographed film unit, and sets the next film unit to the exposure opening.

By the way, if the light-shielding cover is pushed through the exposure opening of the film pack before being loaded into the camera, a gap is generated between the light-shielding cover and the exposure opening, and external light enters through this gap to allow the film unit to be opened. May be exposed. To prevent this, Japanese Unexamined Patent Publication No.
In Japanese Patent Publication No. 32, a pair of arc-shaped unit support projections are provided at both ends of a surface facing the exposure opening. The pair of unit support projections are in contact with the back surface of the lowermost film unit, and push up the central portion thereof in an arc shape so as to project toward the exposure opening. As a result, the pressing down of the light-shielding cover is regulated by the thickness of the plurality of film units and the projection amount of the unit supporting projection, so that the gap formed between the exposure opening and the exposure opening is very narrow. The external light does not erroneously expose the film unit.

[0005]

In the film pack described in the above-mentioned publication, a plurality of film units are housed in an arcuate manner by unit support projections. Therefore, when the film pack is stored for a long period of time, the film unit has the above-mentioned warping habit, and when the film unit is set in the exposure opening, the flatness of the exposed surface is impaired, and There was a possibility that defocus would occur in the part.

An object of the present invention is to provide a film pack in which the flatness of an exposure surface set in an exposure opening is prevented from being deteriorated due to a habit of a film unit caused by being stored in the film pack for a long term. Aim.

[0007]

In order to achieve the above-mentioned object, a film pack according to the present invention comprises a film forming an exposure opening.
A pair of substantially arc-shaped correction ribs whose central portions are convex toward the inside of the pack are provided on the inner walls of two edges parallel to the discharge direction of the sides, and these correction ribs are provided on the exposure surface of the film unit. The side is abutted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2 showing the structure of a film pack according to the present invention, a film pack 10 has a light shielding cover 1 in a case composed of a case body 11 and a lid 12.
3, a plurality of film units 14, and a light shielding sheet 1
5 is stored.

An exposure opening 18 for exposing subject light to the film unit 14 is formed on the front surface of the case body 11. The exposure opening 18 is provided with a notch 19 into which a well-known claw member enters. Further, a slit-shaped outlet 20 for discharging the exposed film unit 14 is formed on the upper surface of the case body 11.
The light-shielding cover 13 is discharged from the discharge port 20 in addition to the film unit 14. The outlet 20 is closed from the outside by a soft light-shielding seal 21. Shield Sticker 2
1, only one edge of the long side of the discharge port 20 is attached so as not to hinder the discharge of the light shielding cover 13 and the film unit 14. The light-shielding cover 13 is overlaid on the film unit 14 set first in the exposure opening 18, and covers the exposure opening 18.

The film unit 14 includes an exposure surface 14a on which a photosensitive layer and a light-receiving layer are provided, a developing solution pod 14b containing a developing solution, and a developing solution pod 14b.
and a trap portion 14c for capturing and hardening the excess developing solution that has flowed into the exposure surface 14a from b. The film unit 14 is a mono-sheet type having a vertically-long rectangular shape which can be handled as one sheet until the end, and in the present embodiment, is discharged along a long side (up and down) direction.

The cover 12 has two holes 12a and 12b,
Two unit support protrusions 12 c and 12 d are provided, and are attached to the case main body 12 so as to face the exposure opening 18. The two holes 12 a and 12 b are provided at predetermined intervals above and below the lid 12, and serve as entrances when a push-up member provided on the camera side enters the inside of the pack 10 when loaded into the camera.

The unit supporting projections 12c and 12d are
2 are provided on both side ends in a vertically long shape, and have a shape protruding in an arc shape toward the exposure opening 18. These unit support protrusions 12c and 12d
8, the film unit 14 is pushed up in an arc shape having a central portion protruding toward the exposure opening 18, and the light-shielding cover 13 is exposed by careless handling. Exposure aperture 1 from
8 and pushed toward the lid 12, the exposure aperture 18
The gap formed between the film unit 14 and the light-shielding cover 13 is narrowed to prevent the film unit 14 from being exposed to external light entering from the gap.

The light shielding sheet 15 is composed of two sheets 23 and 24 made of elastic plastic. One of the sheets 23 has a central portion attached to the lid 12, shields the two holes 12a, 12b of the lid 12 before being loaded into the camera, and has cutout portions 23a, 23b at both ends of the center. After loading, the upper and lower ends are elastically bent toward the exposure opening 18 by pushing up the push-up member on the camera side, and push up the film unit 14 toward the exposure opening 18 via the other sheet 24. These sheets 23, 2
4 has a shape in which the upper and lower ends are bent toward the exposure opening 18 in order to push the developing solution pod 14b and the trap portion 14c behind the exposure surface 14a.

The other sheet 24 has a lower end attached to a lower end 23c (a hatched area) of the one sheet 23 to prevent the one sheet 23 from loosening and to prevent light from leaking from the holes 12a and 12b. And when the one sheet 23 is elastically bent by the push-up member on the camera side, the film unit 14 is pushed up substantially in a plane.

As shown in FIGS. 1 and 3, a pair of correction ribs 25 are provided on the inner wall of the exposure opening 18 to force the film unit 14 to maintain the flatness of the exposure surface 14a. These correction ribs 25 are provided on the inner walls of the four edges forming the exposure opening 18 which are parallel to the discharge direction of the film unit 14 and extend linearly in the discharge direction. Each of the pair of correction ribs 25 is provided with a substantially circular arc surface 25a in which a portion corresponding to a substantially center of a vertical (discharge direction) side of the film unit 14 is maximally convex toward the lid 12 side. ing. Arc surface 25
The surface on the side of the exposure surface 14a of the film unit 14 set in the exposure opening 18 is pressed against a. As the substantially arc shape of the arc surface 25a, any one of a circle, an ellipse, a smooth curve, and a smoothly connected straight line,
Alternatively, it may be configured by combining any of these.

The thus configured film pack 10
In the unused state, as shown in FIG. 4, the exposure opening 18 is a light shielding cover 13 and the discharge port 20 is a light shielding seal 21.
Further, the holes 12a and 12b are closed with the light shielding sheets 15, respectively, and the inside is shielded from light. Also, the exposure aperture 18
The unit support projections 12c and 12d are in contact with both ends of the rear surface of the film unit 14 which is set last.
Since the exposure surface 14a of the film unit 14 is thinner than the developing solution pod 14b and the trap portion 14c, the film unit 14 is set in the exposure opening 18 by the contact of the arc-shaped unit support projections 12c and 12d. Several film units 14 on the last side are in a state of being curved in a circular arc shape with the central part convex toward the exposure opening 18.

When the film pack 10 is loaded in the film loading chamber of the camera, as shown in FIG.
The push-up members 27 and 28 on the camera side enter from b and push up the sheet 23 toward the exposure opening 18. As a result, the sheets 23 and 24 are attached to the last film unit 1.
4 and is warped in an arc shape with the central portion convex toward the exposure opening 18.

On the camera side, a shutter release operation is performed once in preparation for photographing. Thereby, the claw member on the camera side enters the notch 19 and engages with the rear end corner of the light shielding cover 13 so that the claw member removes the light shielding cover 13 from the discharge port 20.
And the light-shielding cover 13 is
It is discharged while pushing up. When a predetermined length of paper is discharged from the discharge port 20, a developing roller provided on the camera side outside the discharge port 20 nips the upper end of the light-shielding cover 13 and discharges the outside of the camera. As a result, on the side of the film pack 10, the uppermost film unit 14 is
The camera is ready for shooting.

For photographing, a shutter release operation is performed in the same manner as described above. Thus, the exposed film unit 14 is scraped out toward the discharge port 20 by the claw member.
The film unit 14 is discharged toward the developing roller while pushing up the light-shielding seal 21 as indicated by a two-dot chain line, and the developing solution pod 14b is split by the developing roller. The developing solution flowing out of the developing solution pod 14b is exposed to the lower exposure surface 14a by the pressing of the developing roller.
While being deployed to the outside of the camera.

Thereafter, the film unit 14 is discharged every time an image is taken by the camera. When the lowermost film units 14 are stored for a long period of time, as shown in FIG. 6, the film units 14 have a habit in the form of an arc whose central portion is convex toward the exposure opening 18. However, as shown in FIG. 7, even when the film unit 14 having such a habit is set in the exposure opening 18, both ends of the exposure surface 14 a are pressed against the substantially circular arc surface 25 a of the correction rib 25, Since the shape is followed, the above-mentioned habit is corrected. Thus, the film unit 14 set in the exposure opening 18 maintains the flatness of the exposure surface 14a, and can prevent inconvenience such as defocusing.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to determine the maximum projection amount of the correction rib 25,
An experiment was conducted to determine the flatness at normal temperature and the flatness under high-temperature and high-humidity conditions with respect to the maximum protrusion amount, and Table 1 shows the results.

[0022]

[Table 1]

The maximum amount of protrusion is determined by the developing solution pod 14b or the trap portion 14c on the inner wall of the film pack 10.
Indicates the length that protrudes maximally from the surface with which abuts. The maximum projecting position was a position corresponding to substantially the center of the vertical (discharge direction) side of the film unit 14. The length of the side parallel to the longitudinal direction is 85.
The size of the exposure screen 18 was 62.1 mm long (discharge direction) × 46 mm wide. The judgment is
Irregularities are measured at a plurality of positions in the range of the exposure surface 14a, and the minimum and maximum values are ± 1 m from the focus setting position of the camera.
The case where the value is within the standard of m is indicated by Δ, and the case where the value is out of the standard is indicated by ×. According to this, the amount of protrusion of the correction rib 25 is set to 0.
5-1.5 mm has been found to be suitable. The maximum protrusion amount of the correction rib 25 differs depending on the size of the film unit and the size of the exposure screen 18.

In the above embodiment, the portion of the arc surface 25a of the straightening rib 25 corresponding to the center of the side parallel to the discharge direction of the film unit 14 is set as the maximum projecting position, but the present invention is not limited to this. For example, the center of the edge of the exposure screen 18 parallel to the discharge direction may be made to protrude to the maximum.

[0025]

As described above, according to the instant film pack of the present invention, the exposed surface of the film pack having an arc-shaped habit whose central portion is convex toward the exposure opening is corrected by the correction rib. , The flatness of the exposed surface is maintained,
Inconveniences such as defocusing can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a state where a case body and a lid according to the present invention are combined.

FIG. 2 is an exploded perspective view showing the structure of the film pack.

FIG. 3 is a cross-sectional view of a state where a case body and a lid are combined.

FIG. 4 is a longitudinal sectional view of the film pack.

FIG. 5 is a longitudinal sectional view showing a film pack loaded in a camera.

FIG. 6 is an explanatory diagram showing a film pack having a habit due to long-term storage.

FIG. 7 is a longitudinal sectional view showing a state where the last film pack is set in an exposure opening.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Film pack 11 Case main body 12 Lid 12c, 12d Unit support projection 13 Light shielding cover 14 Film unit 14a Exposure surface 15 Light shielding sheet 25 Straightening rib

Claims (1)

[Claims] A film unit housed therein;
In an instant film pack having a rectangular exposure opening for giving an exposure to the film unit and a discharge opening for discharging the exposed film unit to the outside, discharging of four sides constituting the exposure opening A pair of substantially arc-shaped correction ribs whose central portions are convex toward the inside of the pack are provided on the inner walls of the two edges parallel to the direction, and the exposure surface side of the film unit is brought into contact with these correction ribs. An instant film pack characterized in that: