JPH08184941A - Photographic film package and its production - Google Patents

Abstract

PURPOSE: To improve light shielding ability and to restrain scratches. CONSTITUTION: By folding a light shielding sheet 20 in two, a folded part 21 is formed. A light shielding envelope 3 is constituted by setting the folded part 21 as one side edge, bonding the other side edge by a side seal tape 22, and bonding a leading edge by an adhesive layer. The folding angle in a central area is made gentler than the folding angle of a leading edge area and a trailing edge area in the folded part 21. Then, light shielding projected lines 11 and 12 are formed at both side parts near an insertion port 5. The curved surfaces of the projected lines 11 and 12 at the side ends in the central part in terms of the envelope 3 are formed to be a gentle curved surface having the large radius of curvature. Thus, contact pressure between the ends of the projected lines 11 and 12 and photographic film 15 is dispersed, and the film 15 is prevented from being scratched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic film package in which a sheet-shaped photographic film is housed in a light-shielding envelope so that it can be freely taken in and out, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a professional photographic film, a photographic film package in which a sheet-shaped photographic film having a relatively large size (for example, 12.5 × 10 cm) is housed in a light-shielding envelope is proposed in, for example, JP-A-4-356039. ing. The light-shielding envelope is formed with an insertion port through which the photographic film is taken in and out, and since this insertion port is normally closed with a light-shielding clip, it is not exposed to external light.

This photographic film package is used by loading it in a film holder mounted behind the camera.
When loading, operate the lock lever of the film holder to set it in the unlocked position. After that, the photo film package is inserted into the film holder with the light blocking clip at the top, and then the lock lever is set to the lock position to lock the light blocking clip. In this state, when only the light-shielding envelope is pulled out partway from the camera, the light-shielding clip and the light-shielding envelope are disengaged, and the photographic film is set in the exposure opening of the camera to enable photographing. After the shooting, the light-shielding envelope is pushed into the film holder, and the photographed film is inserted into the light-shielding envelope. When the photographic film is completely inserted into the light-shielding envelope, the insertion opening is closed by the light-shielding clip, and the photographic film is light-tightly stored in the light-shielding envelope. After that, when the lock lever is set to the unlocked position and the light-shielding envelope is pulled out together with the photographic film, the photographic film package is taken out from the film holder.

[0004]

In such a photographic film package, when the light-shielding envelope is pushed into the film holder after the photographing is finished, the light-shielding envelope is fitted with a slight gap between the tip of the light-shielding envelope and the light-shielding clip. Or if
When the light-shielding envelope is laterally displaced and the end portion of the insertion opening extends out of the outline of the light-shielding clip, the light entering the light-shielding envelope from the insertion opening causes a problem of exposing the photographed photograph. Therefore, the applicant of the present invention has filed Japanese Patent Application Laid-Open No. 5-216617.
No. 3 proposes that light-shielding ridges are formed on both sides of the light-shielding envelope near the insertion port to improve the light-shielding property. However, when simply forming the light-shielding ridge,
A part of the curved surface at the end of the light-shielding ridge may come into strong contact with the photographic film, which may cause scratches.

Further, since the photographic film package is disposable, the light-shielding envelope is manufactured from carbon-mixed black paper having a thickness of about 240 μm, and the manufacturing cost is suppressed. Moreover, since the light-shielding envelope is formed by stacking the upper sheet and the lower sheet on each other, the side edges are joined with the side seal tape, and the tips are joined with the adhesive.
Two light-shielding sheets and two side seal tapes are required, which increases the manufacturing cost, and two side seal tape sticking devices are required, which increases the equipment cost.

Therefore, in order to reduce the manufacturing cost, instead of using two side sealing tapes, one light shielding sheet is folded in two, one side edge is formed of a bent portion, and the other side edge only. It is considered that they are joined by a side seal tape. However, simply folding the sheet in half reduces the bending rigidity of the light-shielding envelope by one sheet of the side sealing tape as compared with the case of using two side sealing tapes. Therefore, the light-shielding envelope may be bent at the time of loading into the film holder, resulting in defective loading. In particular, since the exposed photographic film is inserted into the light-shielding envelope after completion of photographing, when the light-shielding envelope is pushed into the film holder, only the light-shielding envelope is pushed in, so that the light-shielding envelope is easily bent due to insufficient rigidity. When the light-shielding convex strip is formed on the light-shielding envelope formed by folding in two, the thickness of the side edge formed by bending and the side edge formed by the side seal tape are changed depending on the presence or absence of a joining member. This makes it difficult to make the light-shielding ridges the same height. As a result, one of the light-shielding ridges projects, and the contact pressure of the photographic film on the projecting ridges increases, so that scratches are likely to occur.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to suppress the occurrence of scratches in a photographic film package in which a light-shielding ridge is formed near the insertion opening of a light-shielding envelope. Another object of the present invention is to keep the manufacturing cost of the photographic film package low.

[0008]

In order to achieve the above object, the photographic film package according to claim 1 has a gradual curved surface having a large radius of curvature at the end of the light-shielding convex strip on the side of the central portion of the light-shielding envelope. It was formed in. The photographic film package according to claim 2 has 2
A light-shielding envelope is constructed by joining together a plurality of light-shielding sheets. In the photographic film package according to the third aspect of the invention, the folded portion of the light-shielding sheet folded in two is used as one side edge, and the other side edge and the leading edge are joined to form a light-shielding envelope. Further, in the photographic film package according to the fourth aspect, the bending angle of the bent portion near the central portion of the light-shielding envelope is made looser than the bending angle at both ends of the light-shielding envelope.

According to a fifth aspect of the present invention, in the method of manufacturing a photographic film package, the light shielding sheet is folded in two,
The bent portion is one side edge, and the other side edge and the leading edge are joined by a joining member to form a light-shielding envelope, and the bent portion side embossing convex piece and the joining member side embossing convex piece Using a die for embossing, a light-shielding convex strip is formed on both side edges near the insertion opening of the light-shielding envelope, and the protrusion height of the embossing convex piece is the same as that on the bending portion side on the joining member side. It is set so as to be lower than the one corresponding to the joining member.

[0010]

The light-shielding ridges are formed on both sides of the light-shielding envelope in the vicinity of the insertion port. The end of the light-shielding convex strip on the side of the central portion of the light-shielding envelope is formed by a gently curved surface having a large radius of curvature, which prevents the photographic film from locally contacting. Therefore, since the contact pressure is lowered, the occurrence of scratches is suppressed.

When the light-shielding sheet is folded in two and the bent portion of the light-shielding sheet is one side edge and the other side edge and the leading edge are joined to form a light-shielding envelope, the center of the light-shielding envelope is formed. The bending angle of the bent portion near the portion is set to be less than the bending angle of both ends of the light-shielding envelope. Therefore, in the cross section orthogonal to the bending line of the light-shielding envelope,
The cross-sectional area of the central portion is larger than that of the both end portions, and the central portion has a swollen shape. Therefore, the bulge improves the rigidity of the light-shielding envelope against bending, and the light-shielding envelope is not bent during the operation of inserting the photographed film into the light-shielding envelope. In addition, since the angle at the bent portions at both ends is more acute than that at the central portion, it is possible to reduce the gap at the insertion opening, and even if the cross-sectional area of the central portion is increased, the light wraps around from the insertion opening. It is possible to suppress the deterioration of the light blocking effect.

Further, with respect to such a light-shielding envelope that is bent, the thickness of both side edge portions varies depending on the presence or absence of a joining member. Therefore, in consideration of the protrusion height of the embossing convex piece of the embossing die corresponding to the joining member, the joining member side is lower than the bending portion side by the amount corresponding to the joining member. Is set to. As a result, the protrusion heights of the light-shielding ridges in the light-shielding envelope are the same on both sides, the contact pressure between the photographic film and the light-shielding ridges is substantially the same, and the occurrence of scratches on the photographic film is suppressed.

[0013]

EXAMPLE FIG. 2 shows a photographic film package in which a photographic film unit is pulled out from a light-shielding envelope. The photographic film package 2 comprises a light-shielding envelope 3 and a photographic film unit 4 housed in the envelope. At the rear end of the light-shielding envelope 3, there is formed an insertion opening 5 for inserting and removing the photographic film unit 4. A light-shielding clip 6 is provided at the rear end of the photographic film unit 4. This light-blocking clip 6 is used as the insertion port 5 for the light-blocking envelope 3.
And the insertion port 5 is shielded from light. An adhesive tape 7 is detachably attached to the tip of the light-shielding envelope 3. This adhesive tape 7 is used for the light-shielding envelope 3 after the end of shooting.
And the light-shielding clip 6 so that the light-shielding envelope 3 does not come off from the light-shielding clip 6. The adhesive tape 7 has its corners arranged in a notch 8 formed at the tip of the light-shielding envelope 3 so that it can be easily peeled off.

Further, a stopper member 9 made of a band-shaped thick paper is attached to the surface of the light-shielding envelope 3 located near the insertion port 5 on the lens side when loaded in the camera. When only the light-shielding envelope 3 is pulled out in the film holder, the stopper material 9 is locked to a locking portion in the film holder and restricts further pulling out. This prevents the light-shielding envelope 3 from falling out of the film holder.

Further, the stopper member 9 is provided at the tip of the light-shielding envelope 3.
On the surface opposite to the surface on which is attached, a handholding material 10 made of cardboard is attached. The handholding material 10 can be easily grasped with a finger when the light-shielding envelope 3 is pulled out. A notch 10a is formed in the central portion of the handle member 10 so that the upper sheet and the lower sheet of the light-shielding envelope 3 can be directly gripped when the whole of the handle member 10 is pulled out. The portion to which the handholding material 10 is attached projects to the outside from a film holder (not shown) of the camera when the photographic film package 2 is loaded into the camera.

The light-shielding envelope 3 is placed near the insertion port 5 of the light-shielding envelope 3.
Light-shielding ridges 11 and 12 are formed on both sides of the light-shielding clip 6 at positions held by the light-shielding clips 6. Shading ridge 1
1, 12 are arranged in a direction orthogonal to the inserting direction of the photographic film unit 4, and are formed by embossing, as will be described later in detail. Shading ridge 11,1
2 has an arc-shaped cross section, and the length is 12 mm and the protruding height is 0.4 mm with respect to the size of the light-shielding envelope 3 (width 110.8 mm × length 240 mm). The length is 8 to 15 mm, and the protrusion height is preferably 0.2 to 1.0 mm.

The light-shielding clip 6 is provided on the first carrier sheet 14
It is crimped and fixed to the rear end of the. The front end of the first carrier sheet 14 is releasably joined to the rear end of the photographic film 15 via hot melt. A hole 14a for determining the front and back of the photographic film 15 is formed at the end of the first carrier sheet 14. The rear end of the second carrier sheet 16 is releasably joined to the front end of the photographic film 15 via hot melt. The second carrier sheet 16 has a leading end cut into a trapezoidal shape in order to easily insert and remove the photographic film unit 4 into and from the light-shielding envelope 3. This second carrier sheet 1
A step correction sheet 17 for eliminating a step with the photographic film 15 is attached to the sheet 6.

A slit 18 and three round holes 19a, 19b and 19c are formed along the longitudinal direction of the slit 18 in the trapezoidal portion of the tip of the second carrier sheet 16. The slit 18 is for directly contacting the upper sheet and the lower sheet of the light-shielding envelope 3 when the light-shielding envelope 3 is pinched by a finger, whereby the light-shielding envelope 3 and the photographic film unit 4 are kept together without being displaced. To be able to draw out. Also, three round holes 19a, 19b, 1
9c are arranged at different intervals so that the front and back of the photographic film unit 4 can be detected under a safelight. Therefore, it is possible to prevent the front and back of the photographic film unit 4 from being reversed and inserted into the light-shielding envelope 3 at the factory.

As shown in FIG. 3, in the light-shielding envelope 3, one sheet of the light-shielding sheet 20 having a multi-layer structure is folded in two at a folding portion 21, and the folding portion 21 serves as one side edge and the other side. The edges are joined with a side seal tape 22 and the leading edge is joined with an adhesive layer 23. The light-shielding envelope 3 is manufactured in a light-shielding envelope manufacturing line (not shown) by the processing procedure as shown in FIG. First, pull out the roll-shaped shading sheet 20,
Fix curl with decurler device. Next, the stopper material 9 is attached to a predetermined position of the light shielding sheet 20 by a stopper material attaching device. Next, the wiper material (not shown) is applied to the wiper material at a predetermined position on the light shielding sheet 20. The wiper material is made of non-woven fabric, and the light-shielding envelope 3
It is affixed to the inner surface of the to capture dust and the like adhering to the photographic film. Next, the center position of the light shielding sheet 20 is set by the light shielding sheet centering device. Next, a fold forming device is used to form folds along the center line of the light shielding sheet 20. Next, a cut is formed in the light-shielding sheet 20 to reach the fold by a pressing device. This cut is formed at a position where the light shielding sheet 20 is divided into each bag. Next, the folding is performed by the folding machine based on the crease, and the bending angle of the folding portion is adjusted by the thermal pressure machine.
After the bending, the portion to be the tip of the light-shielding envelope 3 is thermocompression bonded by a thermocompression bonding machine. Next, the side seal tape 22 is pasted by a side seal tape pasting machine to join the side edges of the light-shielding envelope 3. Next, the hand-held material attaching device attaches the hand-held material 10 to a predetermined position of the light shielding sheet 20. Next, the light shielding sheet 20 is cut into each bag by the cutting device. Next, a trimming device is used to perform trimming cutting so as to form the light-shielding envelope 3 and formation of the light-shielding convex strips 11 and 12. Next, the final thermocompression bonding (complete thermocompression bonding) of the handholding material 10 is performed by a thermocompression bonding machine. The light-shielding envelope 3 is completed by this series of processes. The completed light-shielding envelope 3 is stacked in the stocker of the stacking device.

As shown in FIG. 1, the light-shielding convex strips 11 and 12 are embossed by using embossing dies 30 and 31. The embossing dies 30, 31 are composed of upper dies 30a, 31a and lower dies 30b, 31b.
Embossed convex pieces 33, 34 are formed on a,
Embossed recesses 35, 36 are formed in the lower molds 30b, 31b. As shown in FIGS. 5 and 6, the embossed convex pieces 33, 34 are formed so as to project so that the cross section (cross section orthogonal to the longitudinal centerline of the embossed convex pieces) has an arc shape. The shape of the embossed convex piece 33 for forming the light-shielding convex strip 11 on the bent portion side is the protrusion height H1.
(H1 = 0.7 mm), and the cross-sectional shape has a radius r1 (r
It is an arc of 1 = 0.5 mm). The shape of the embossed convex piece 34 for forming the light-shielding convex strip 12 on the side seal tape side is a protrusion height H2 (H2 = 0.6 mm), and the cross-sectional shape is a radius r2 (r2 = 0.5 mm). It is an arc. Further, as shown in FIG. 7, the curvature radius RX of the curved surface of the end portion in the vertical cross section of the embossed convex piece 33 (the cross section including the center line in the longitudinal direction of the embossed convex piece) is, as will be described in detail later, a photographic film. Within a predetermined range in order to lower the contact pressure of.

The protrusion heights H1 and H2 of the embossed convex pieces 33 and 34 on both sides of the light-shielding envelope 3 are changed in consideration of the thickness of the side seal tape 22. That is, when the thickness of the side seal tape 22 is 90 μm, the amount of compression collapse during embossing is 80 μm. Therefore, 180-80 = 100
(Μm) is the thickness difference D1 between the bent side and the side seal tape side, and the embossed convex piece 34 on the side seal tape 22 side is changed by the thickness difference D1. It is lower than 33. Therefore, even if there is a difference in thickness between both sides, the light-shielding ridges 11, 12
Since the maximum protrusion amounts H3 and H4 of the photo film 15 are made uniform, the photographic film 15 uniformly contacts the light-shielding convex strips 11 and 12, the contact pressure is dispersed, and the occurrence of scratches is suppressed.

Light-shielding envelope 3 of embossed convex pieces 33, 34
If the radius of curvature of the curved surfaces 33a and 33b at the end on the central portion side is small, the contact with the photographic film is localized and the contact pressure becomes high, so that scratches easily occur. Therefore, in FIG.
As shown in FIG. 5, the radius of curvature RX of the curved surface 33a is set large, and the curved surface 33a is finished into a smooth surface so that the photographic film does not come into contact locally. The curved surface 34a of the other embossed convex piece 34 has the same structure. The radius of curvature RX is the length L of the light-shielding ridge 11 to be formed when the radius r1 of the arc in the cross section of the embossing convex piece 33 (the section orthogonal to the longitudinal centerline of the embossing convex piece) is 0.5 mm. When the curvature radius RX is 22 mm or more, no scratches were generated and a favorable result was obtained. The radius of curvature RX is preferably as large as possible from the viewpoint of suppressing the generation of scratches, but the light-shielding convex strip 11
The radius of curvature RX is as short as 5 to 15 mm.
The larger the value, the lower the light blocking effect. Therefore, in the case of the size of the light-shielding convex strip 11 as described above, the radius of curvature RX is set to 3
It is preferably 0 mm or less. Therefore, the radius of curvature RX is preferably in the range of 20 to 30 mm in order to satisfy both the suppression of the generation of scratches and the light-shielding property. Particularly preferable range is 22 to 28 mm. Table 1 shows the results of experiments on the scratch suppressing property and the light shielding property by changing the radius of curvature RX.

[0023]

[Table 1]

The meaning of each evaluation in Table 1 is as follows. ◎ ... very good. O: Excellent. ● ・ ・ ・ Yes (within practical limits) ▲ ・ ・ ・ Problem (improvement required). ×: Not practical.

In the thermocompression bonding machine, as shown in FIG. 8, the bending portion 21 is divided into three areas A1, A2 and A3, and the pressing pressure is changed for each area to finely adjust the bending angle.
For the central area A2, the tip area A shown by hatching
1 and the trailing end region A3, the pressing pressure is lowered to press the bending angle of this region A2 more loosely than the other regions A1 and A3. As a result, as shown in FIG. 9, the bending angle in the central region A2 becomes gentle, the cross-sectional area of the light-shielding envelope 3 increases, and the bending rigidity in this region A2 can be improved. Further, the front end region A1 and the rear end region A
In No. 3, as shown in FIG. 10, the bending angle becomes tight and the cross-sectional area of the light-shielding envelope 3 does not increase so much. In particular, in the rear end region A3, the gap at the insertion port 5 can be made small, and the light blocking effect can be improved.

The rate at which the envelope is broken is reduced by increasing the ratio of the central area A2, but if the ratio of the central area A2 is increased too much, the opening area of the insertion port 5 is increased and the light shielding property is impaired. I will end up. Therefore, the ratio of the central area A2 to the entire length of the bent portion 21 is set to 40 to 86%, and the remaining area is equally divided into areas A1 and A3. Experiments have shown that it can be obtained.

Further, in order to improve the bending rigidity of the light-shielding envelope, as shown in FIG. 11, the light-shielding sheet 20 is a pair of papers 20 in which carbon black is mixed on both sides of a polyolefin thermoplastic resin sheet such as a polyethylene sheet 40.
It has a structure in which a and 20b are joined. Paper 20a, 20
The joining of b is performed by extrusion lamination of polyethylene. In such a light-shielding sheet 20, the curl can be further reduced as compared with a paper coated with resin on one surface. As the papers 20a and 20b, those having substantially the same expansion / contraction rate with respect to temperature changes and humidity changes are used so that the curl balance is not disturbed. Paper 20
a is the inside of the light-shielding envelope 3, and the photographic film unit 4
Therefore, a lubricant layer 41 coated with 1 g / m ^{2 to} 15 g / m ² of wax is formed on the side of the paper 20 a that contacts the photographic film. The lubricant layer 41 makes it possible to smoothly pull out and push in the light-shielding envelope 3 and prevent the photographic film unit 4 from being scratched. Although the light-shielding envelope 3 is manufactured by extrusion lamination in this embodiment, it may be manufactured by dry lamination or wet lamination. Although a polyethylene resin is used as the thermoplastic resin, various polyolefin resins (a homopolymer resin, a copolymer resin, and a mixed resin of two or more kinds) may be used.

Even with the above structure, the papers 20a, 20
If the basis weight of b is 60 g / m ² or less, the bending rigidity of the light-shielding envelope 3 cannot be sufficiently ensured, and therefore the photographic film package 2 is bent when it is taken in and out of the film holder. If the basis weight is 120 g / m ² or more, it becomes difficult to put the film in and out of the film holder. As a result, the basis weight of the paper 20a, 20b is 60 g / m ²
It is preferably 120 to 120 g / m ² . In this embodiment, the papers 20a and 20b have a basis weight of 90 g / m ² . Further, the papers 20a and 20b have carbon black concentrations of 2 wt% to 15 wt% (1.2 g / m ^{2 to} 18 g / m).
^{In 2} ), the reflection of light is suppressed on the surface of the light-shielding envelope 3, and the light-shielding property of the light-shielding envelope 3 is secured. Note that paper 2
When 0a and 20b are mixed with not only carbon black but also a black dye such as a cationic dye, the light-shielding property can be further enhanced.

The light-shielding envelope 3 must prevent the reflection of light on the surface, and it is essential to color the papers 20a and 20b. However, regarding the light-shielding property, a combination of the papers 20a and 20b and the polyethylene sheet 40 is used. You may consider. For example, carbon black may be kneaded into the polyethylene sheet 40 to secure the light shielding property. In this case, the carbon black concentration should be 0.5 wt% to 10 wt%.
Is preferably within the range. By doing so, even if the photographic film package 2 is left under the illumination of 100,000 lux for 10 minutes, the inside of the light-shielding envelope 3 can be kept light-tight.

The polyethylene sheet 40 has a thickness of 10
If the thickness is less than μm, the polyethylene film will not be formed well during lamination, and the adhesive force with the paper 20a, 20b will be insufficient. Further, when the thickness of the polyethylene sheet 40 is 70 μm or more, the workability at the time of laminating becomes poor and the cost increases. Therefore, the thickness of the polyethylene sheet 40 is 10 μm to 70 μm.
It is preferable to set it within the range of m. 10 μm to 7
The polyethylene sheet 40 having a thickness of 0 μm has a basis weight of 10 g.
/ M ^{2 to} 70 g / m ² . The polyethylene sheet 40 having such a thickness can sufficiently secure moisture resistance and can prevent moisture from entering the inside of the light-shielding envelope 3. If the papers 20a and 20b are made of waterproof paper or the papers 20a and 20b are made waterproof, the light-shielding envelope 3 can be made more moisture-proof. Furthermore, by impregnating the paper 20a, 20b with a resin, the bending rigidity of the light-shielding envelope 3 can be further increased.

The operation of the photographic film package 2 thus constructed will be described. As shown in FIG. 2, the photo film package 2 has a rear end portion of the light-shielding envelope 3 clamped by a light-shielding clip 6 and an insertion opening 5 closed.
The photo film package 2 is loaded into the film holder with the clip 6 first. At the time of this loading, the film holder is set to the unlocked state. After this insertion, the light-shielding clip 6 is set in the locked state and the light-shielding clip 6 is locked to the film holder.

In this state, when the handholding material 10 is lightly grasped and pulled, the light-shielding envelope 3 is disengaged from the light-shielding clip 6,
Only the light-shielding envelope 3 is pulled out as shown in FIG. Wax is applied to the inside of the light-shielding envelope 3, so that the photo film unit 4 can be pulled out.
The photo film 15 will not be scratched even if the
Withdrawal is done smoothly. Further, dust or the like attached to the photographic film is captured by a wiper material (not shown) in the light-shielding envelope 3.

After the photographing is finished, the light-shielding envelope 3 is pushed into the film holder, and the photographed film unit 4 having been photographed.
Are stored in the light-shielding envelope 3. The light-shielding envelope 3 has a central area A
Since the second bent portion 21 increases the cross-sectional area of the central region A2, the bending rigidity is improved.
Therefore, even if the light-shielding envelope 3 is pushed into the film holder, the light-shielding envelope 3 is not bent, and the light-shielding envelope 3 can be smoothly stored in the film holder. Moreover, since the bending angle of the bent portion 21 of the rear end region A3 is tight, there is no gap in the insertion port 5 and reliable light shielding is obtained, and the rear end portion of the light shielding envelope 3 is connected to the light shielding clip 6. It fits smoothly.

Next, when the film holder is set in the unlocked state and the notch 10a is firmly grasped, the upper and lower surfaces of the light-shielding envelope 3 come into direct contact with each other through the slit 18. In this state, when the light-shielding envelope 3 is pulled out, the photographic film unit 4 is pulled out from the film holder together with the light-shielding envelope 3 without being displaced. After this,
The adhesive tape 7 is peeled off from the front end of the light-shielding envelope 3, and is attached to the insertion port 5 and the light-shielding clip 6 of the light-shielding envelope 3 to prevent the photographic film unit 4 from coming off from the insertion port 5.

FIG. 12 shows a cross section of a light-shielding sheet 50 according to another embodiment. In FIG. 12, a polyethylene sheet 40 as shown in FIG. 11 is formed by joining a pair of papers 20a, 20b mixed with carbon black on both sides. On the other hand, on the printing ink layer 45 formed by printing, two layers of curing agent layers 46a and 46b formed by applying a curable varnish twice, and further forming a lubricant layer 47 on the curing agent layer 46b. Is configured. The same components as those shown in FIG. 11 are designated by the same reference numerals. The curing agent layers 46a and 46b are shown in Table 2
The main agent is composed of the composition as shown in (1) and the curing agent is 100% of xylene diisocyanate (XDI). The curing agent is added to the main agent in an amount of 5%. The constituents of the lubricant layer 47 are shown in Table 3. The coating amount (thickness) of each layer is 0.5 to 3 μm in one coating.

[0036]

[Table 2]

[0037]

[Table 3]

In this way, the curing agent layers 46a and 46b are formed into two layers.
By forming a layer and forming one layer of the lubricant layer 47 on this, cracks do not occur on the surface of the bent portion 21, and the bending rigidity when formed on the light-shielding envelope 3 is satisfactory. Was obtained.

In the above embodiment, the light-shielding envelope 3 is formed by bending, but in addition to this, both side edges of the two light-shielding sheets are joined by the side seal tape and the leading edges are joined by the adhesive layer to shield the light. An envelope may be formed. Also in this case, the light-shielding ridges 11 and 12 having the shape shown in FIG. 1 are formed near the insertion port of the light-shielding envelope. By forming the ends of the light-shielding convex strips 11 and 12 on the side of the central portion of the light-shielding envelope 3 by the embossing convex piece as shown in FIG. 7, the end portions become gentle curved surfaces, and the occurrence of scratches is suppressed. At the same time, the light shielding property can be improved.

In the above embodiment, the light-shielding ridges 11 and 12 are formed by embossing, but the light-shielding ridges 11 and 12 are formed.
May be formed by, for example, a press roller or the like. In this case, when forming the end portion, the pressing amount of the press roller is gradually reduced so that the end portion has a gently curved surface.
Further, in the above embodiment, the light-shielding convex strips 11 and 12 are formed in the final thermocompression bonding step, which is the final step, but they may be formed in independent steps. In addition, the light-shielding ridges 11,
Although 12 is formed so as to be substantially parallel to the insertion port 5 of the light-shielding envelope 3, it may be formed obliquely with respect to the insertion port. In this case, the insertion resistance due to the light-shielding ridges at the time of fitting the light-shielding clip is dispersed, which facilitates fitting.

In the above embodiment, the pressing pressure of the bending portion 21 is adjusted by the heat pressure at the final stage of the bending process to change the bending angle of each of the areas A1, A2 and A3. The press pressure may be changed by changing the shape of the press die, or by changing the contact pressure or the pressing amount of the press roller. Further, the bending angle may be adjusted in an independent process. Further, the bending angle may be adjusted in the final step of envelope production.

In the above embodiment, the pressing pressure is the same in the same region, but in addition to this, the pressing pressure may be gradually changed near the boundary of each region of the bent portion 21. . In this case, the height of the boundary portion between the portion corresponding to the central region A2 of the press die that presses the bent portion 21 and the portions corresponding to the front end region A1 and the rear end region A3 is gradually changed little by little. The pressing pressure can be changed gently. Therefore, the bending stress when the light-shielding envelope is pushed is not concentrated on the portion where the press pressure changes, and the bending of the light-shielding envelope can be prevented more effectively.

Further, the procedure for manufacturing the light-shielding envelope is not limited to the above embodiment, and various modifications may be added. Also,
Although the hardener layers 46a and 46b and the lubricant layer 47 are formed on the outer side surface of the light-shielding envelope 3, they may be formed on the inner side surface.

[0044]

According to the present invention, since the end of the light-shielding convex strip on the side of the central portion of the light-shielding envelope is formed into a gentle curved surface having a large radius of curvature, the contact between the light-shielding convex strip and the photographic film is localized. Therefore, the contact pressure can be dispersed. Therefore, it is possible to suppress the occurrence of scratches on the photographic film without reducing the light-shielding property.

Since the folded portion of the light-shielding sheet folded in two is used as one side edge and the other side edge and the leading edge are joined to form a light-shielding envelope, two light-shielding sheets are stacked and joined together. The light-shielding envelope can be manufactured more easily than in the case. Moreover, since the number of joints is reduced by the amount of the bent portion, it is possible to reduce the number of complicated devices such as the side seal tape sticking device, which can reduce the equipment cost and improve the suitability for high-speed processing. In this production line, mass production can be efficiently performed.

Since the bending angle near the center of the bent portion of the light-shielding envelope is set to be less than the bending angle at both ends of the light-shielding envelope, the cross-sectional area near the center of the light-shielding envelope can be increased. The bending rigidity can be improved. Therefore, when the light-shielding envelope is pushed into the film holder after the photographing is finished, the light-shielding envelope is not bent, and the light-shielding envelope can be smoothly inserted. In addition, the improvement of the bending rigidity can be easily performed by changing the pressing pressure of the bending portion, and the increase in the number of constituent parts does not occur.

Further, since the bending angle at both ends of the light-shielding envelope is made tighter than that at the central portion, the gap at the insertion port of the light-shielding envelope can be made small and the light-shielding property can be improved. Moreover, the cross-sectional area at both ends of the light-shielding envelope becomes smaller, and the cross-sectional area becomes larger toward the central portion, so that both ends of the light-shielding envelope become wedge-shaped. Therefore, even if the central area of the light-shielding envelope is increased, the light-shielding envelope can be smoothly moved in and out of the film holder.

Further, when manufacturing a light-shielding envelope by bending, an embossing die having an embossing convex piece on the bent side and an embossing convex piece on the joining member side is used,
Light-shielding ridges are formed on both side edges of the light-shielding envelope so that the protruding height of these embossing convex pieces is lower by the amount corresponding to the joining member on the joining member side than on the bent portion side. Since the setting is made, the thickness increases by the amount of the joining member, and even if the left and right side portions have different thicknesses, the protruding height of the light-shielding convex strip inside the light-shielding envelope can be set to be the same on both sides. This allows
The contact pressure on the photographic film is the same between the light-shielding ridges on both sides, and the occurrence of scratches on the photographic film is suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a light-shielding convex strip of a light-shielding envelope embodying the present invention and an embossing die for forming the same.

FIG. 2 is a perspective view showing a state in which a photographic film unit is pulled out from a light-shielding envelope in a photographic film package using the same light-shielding envelope.

FIG. 3 is an exploded perspective view of a light-shielding envelope.

FIG. 4 is a flowchart showing a procedure for manufacturing a light-shielding envelope.

5 is an enlarged cross-sectional view taken along the line VV in FIG.

6 is an enlarged sectional view taken along line VI-VI in FIG.

FIG. 7 is an enlarged cross-sectional view showing the shape of the end portion of the embossed convex piece.

FIG. 8 is a plan view showing a light-shielding envelope.

9 is an enlarged sectional view taken along line IX-IX in FIG.

10 is an enlarged cross-sectional view taken along the line XX in FIG.

FIG. 11 is a cross-sectional view showing a layer structure of a light-shielding sheet that constitutes a light-shielding envelope.

FIG. 12 is a cross-sectional view showing the layer structure of a light shielding sheet in another example.

[Explanation of symbols]

 2 Photo film package 3 Light-shielding envelope 4 Photo film unit 5 Insertion port 6 Light-shielding clip 9 Stopper material 10 Hand-holding material 11, 12 Light-shielding convex strip 14, 16 Carrier sheet 15 Photo film 20 Light-shielding sheet 20a, 20b Paper 21 Folding part 22 Side Sealing tape 30,31 Embossing type 33,34 Embossing convex piece 33a, 33b Curved surface 40 Polyethylene sheet 41,47 Lubricant layer 46a, 46b Hardener layer

Claims (5)

[Claims] 1. A photographic film unit having a sheet-shaped photographic film and a light-shielding clip, an insertion opening closed by the light-shielding clip, and a pair of insertion openings formed on both sides of the insertion opening near the insertion opening. A photographic film package comprising a light-shielding ridge for blocking the entrance of light and a light-shielding envelope for storing a photographic film in a light-tight manner. Photo film package characterized by being formed into a curved surface. 2. The photographic film package according to claim 1, wherein the light-shielding envelope is formed by joining two light-shielding sheets. 3. The photographic film package according to claim 1, wherein the folded portion of the light-shielding sheet folded in two is one side edge, and the other side edge and the leading edge are joined to form the light-shielding envelope. Photo film package featuring. 4. The photo film package according to claim 3, wherein the bending angle of the bent portion near the central portion of the light-shielding envelope is set to be less than the bending angle at both ends of the light-shielding envelope. Film package. 5. A photographic film package comprising a photographic film unit having a sheet-shaped photographic film and a light-shielding clip, and a light-shielding envelope for light-tightly accommodating the photographic film having an insertion opening closed by the light-shielding clip. In the method, the light-shielding sheet is folded in two, the bent portion is one side edge, and the other side edge and the leading edge are joined by a joining member to form a light-shielding envelope, and the embossed protrusion on the bent portion side. A piece and an embossing die having an embossing convex piece on the joining member side are used to form light-shielding ridges on both side edge portions near the insertion opening of the light-shielding envelope, and the protruding height of the embossing convex piece, A method for manufacturing a photographic film package, wherein the joint member side is set lower than the bent portion side by the amount corresponding to the joint member.