JPS63298343A - Instant film unit - Google Patents

Abstract

PURPOSE:To prevent infiltration of a developing soln. into a metallic foil layer even during long-period preservation by laminating a thermoplastic lining layers having alkali resistance in two plies on the side of a pod for sealing the developing soln. where the soln. is enveloped in the metallic foil. CONSTITUTION:The pod 4 mounted on the surface of a drawing out sheet 2 is constituted of 4 layers; a paper layer 40, an aluminum layer 41, a PVC layer 42, and a PVC layer 43. Formation of the PVC layers 42, 43 on the aluminum layer 41 is executed by coating an adhesive agent for lamination on the layer 41, superposing a PVC sheet thereon in a half-dry state and drawing the sheet out of a spacing between press rollers under heating. The PVC 42 is, therefore, laminated on the layer 4. The PVC layer 43 is laminated on the layer 42 by repeating the same procedure. The number of pinholes is thereby decreased to the number much smaller than in the case of using one thermoplastic lining layer and the infiltration of the developing soln. to the metallic foil is prevented even during the long-period preservation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an instant film unit, and more particularly to a pod for enclosing a processing solution.

[Prior art]

A beer-apart type instant film unit (hereinafter referred to as a film unit), as described in detail in Japanese Patent Laid-Open No. 57-62050, uses a developing solution on a drawer sheet bonded to the leading edge of a photosensitive sheet. A sealed pod is attached, and during the development process, the image receiving sheet and the photosensitive sheet are overlapped, and the pod is torn open by a developing roller to push out the developing solution sealed in the pod and process the photosensitive sheet. It is developed between a sheet and an image-receiving sheet, and the image recorded on the photosensitive sheet is transferred to the image-receiving sheet.

The pod has an aluminum layer 41 as shown in FIG.
On the other hand, there is a polyester layer 47. on the side surrounding the developing solution 50. The layer structure includes an alkali-resistant thermoplastic lining layer 48, such as polyvinyl chloride, bonded by adhesive and a paper layer 40 on the other side.

[Problem that the invention seeks to solve]

The thermoplastic lining layer 48 is provided to prevent the aluminum layer 41 from being corroded by the developing solution. However, if the thickness of the thermoplastic plastic lining layer is too thin, it will not be possible to prevent liquid from entering through pinholes, and if it is too thick, the tear seal side of the pound will swell when the pound is manufactured, making it easy to tear, or the rollers will roll when unfolding. There is a problem in that a large amount of developing solution remains in the pod after it has been squeezed out, and a part of the screen may not be developed.

Furthermore, when heat-sealing is performed after filling with a developing solution, the melting points of the thermoplastic plastic lining layer 48 and the polyester layer 47 are different, and due to the difference in heating fluidity before and after heat-sealing, an accident may occur in which they peel off. easy. Furthermore, if there is a pinhole in the thermoplastic lining layer 48, during long-term storage, the processing liquid that has entered through the pinhole may enter the polyester layer 48.
7 and reach the aluminum layer 41.

Furthermore, if there is a pinhole in the polyester layer 47 near the edge of the sealing part, the hole will remain even after sealing due to its high melting point, and if there is a crack in the thermoplastic plastic lining layer 48, the processing liquid will leak into the aluminum layer 41. There is a risk of coming into contact with.

[Purpose of the invention]

The present invention was made in view of the above-mentioned problems.
The thermoplastic lining layer 48 has very few pinholes, and the glabellar peeling phenomenon does not occur during heat sealing. To provide a film unit equipped with a pod that does not reach the metal foil, can close pinholes during heat sealing, and prevents liquid from entering the metal foil layer even during long-term storage.

[Means for solving problems]

In order to achieve the above object, the present invention provides metal foil with:
A double layer of alkali-resistant thermoplastic plastic lining layer is laminated on the side surrounding the developing solution. Metal foils include aluminum foil, lead foil, etc., and alkali-resistant thermoplastic linings include polyvinyl chloride, polyethylene, polypropylene, etc.

[Effect]

According to the above method, since the thermoplastic lining layer is laminated in two layers, the number of pinholes is much smaller than in the case where the thermoplastic lining layer is a single layer, which results in a long-term This prevents the development solution from entering the metal foil even during storage, and
Since there is no longer a need for a thick thermoplastic lining layer, there is no longer a need for the pod to split during pod manufacture or to become partially undeveloped within the screen due to an increase in the amount of processing liquid remaining in the pod when it is expanded. Since the two thermoplastic plastic lining layers are made of the same material, peeling phenomenon due to heat during heat sealing will not occur.In addition, there are pinholes in the thermoplastic plastic lining layer on the processing liquid side, which prevents the processing liquid from peeling off. Even if it invades,
It stops on the surface of another thermoplastic lining layer with excellent alkali resistance. Furthermore, if there is a pinhole in the thermoplastic plastic lining layer on the metal foil side near the edge of the sealing part, for example, the thermoplastic lining layer on the metal foil side will be melted by heat sealing, which will have the effect of closing the pinhole.

Examples will be described below. .

〔Example〕

In FIG. 3 showing the film unit of the present invention, a photosensitive sheet 1 has a pull-out sheet 2 joined to its front end side;
Further, a short skirt 3 is joined to the rear end side for receiving and retaining excess processing solution.

The drawer sheet 2 and skirt 3 are made of paper mixed with carbon in order to eliminate surface reflections. This pull-out sheet 2 has a pod 4 filled with a developing solution and a funnel 5 that guides the developing solution toward the photosensitive sheet 1 attached to the rear end side next to the photosensitive sheet 1. Further, a joint portion 6a of the tab 6 is joined to the tip side thereof.

The image receiving sheet 7 is for recording a final photographic image, and is bonded to the mask 8 via a weak sealing layer. This mask 8 has an opening 8a corresponding to the screen size, and its tip is joined to the drawer sheet 2.

Band-shaped rails 9 and 10 made of relatively thick paper are adhered to both sides of this opening 8a. This rail9.
At the rear end of 10, there are two plate-shaped plates made of hard plastic in order to secure a space to accommodate the excess developing solution and to prevent the excess developing solution from being pushed out by the developing roller described later. The protrusions 11.12 are glued.

FIG. 4 shows the film unit loaded into the film pack. The film pack 20 is loaded with 10 monochrome film units.
To simplify the drawing, only one is shown.

The film pack 20 is composed of a pack main body 21 having an open lower front and bottom surface, a film pressure plate 22 fitted into the pack main body 21, and a bottom plate 23 fitted into the lower part of the pack main body 21. In the film unit, the photosensitive sheet 1 is located above the film pressure plate 22, and the image receiving sheet 7 is located below. The tab 6 protrudes from the film pack 20 so as to be above the pair of developing rollers 25 and 26.

The tab 29 of the second film unit is indicated by a two-dot chain line, and the bent portion of the tab 29 is bonded to the tab 6. Further, the bottom plate 23 is provided with a spring plate 23a for pushing up the leg portion 22a of the film pressure plate 22, and a sponge plate 28 for pushing the image receiving sheet 7 upward.

The pack main body 21 has an exposure window 21a formed on its upper surface, and the photosensitive sheet 1 is exposed to light passing through the exposure window 21a. After exposing the photosensitive sheet 1, if the tab 6 is pulled out by hand, the pull-out sheet 2 is pulled out together with the tab 6.

At this time, the mask 8 moves toward the exit of the film pack 20 while its leading end side gradually turns over and overlaps the pull-out sheet 2. The photosensitive sheet 1 is guided by the rear end of the film pressure plate 22 fitted into the pack body 21, goes around behind it, and is reversed.

As the tab 6 is pulled out through the upper side of the unfolding rollers 25 and 26, when the leading edge of the pull-out sheet 2 comes out a little from between the unfolding rollers 25 and 26, the joint 6a at the rear end of the tab 6 is unfolded. It is peeled off from the drawer sheet 2 due to the imitation action of the rollers 25.

Next, when the leading edge of the pull-out sheet 2 is grasped by hand and pulled out, the pull-out sheet 2 and the mask 8 first pass between the developing rollers 25 and 26 in an overlapping state, and then the photosensitive sheet 1 and the image-receiving sheet 7 The unfolding roller 25,
It passes between 26.

A cross section of the pod 4 of the present invention is shown in FIG. The pod 4 mounted on the surface of the drawer sheet 2 has paper layers 40, 7
/L/minium layer 41. It is composed of four layers: PVC layer 42° and PVC layer 43. Said paper layer 40 is glued by strong adhesive to an aluminum layer 41, and on the other side of the aluminum layer 41 there are two PVC layers 42, 43.

To form the PVC layers 42 and 43 on the aluminum layer 41, a laminating adhesive is applied to the aluminum layer 41,
In a semi-dry state, one PvC sheet is stacked on top of the other and pulled out from between the pressure rollers while being heated. As a result, the PVC layer 42 is laminated to the aluminum layer 41, and by repeating the same procedure, the PVC layer 43 is laminated to the aluminum layer 41.
Laminated onto layer 42.

If 100 is 1m+n in a 30μ PVC layer
” If there is one pinhole, the pv of 15μ
1mm” per 100M in the c layer.

There will be 10 pinholes. Based on this assumption, comparing the probability of pinholes occurring when two 15μ 270 layers are made and the probability of pinholes occurring when there is one 30μ 270 layer, we find that The probability of pinhole existence when layered is 270 of 30μ.
This is 1/1,000,000 times less than when there is only one layer.

The periphery of the pod 4 is filled with the developing solution 50 on the PVC layer 4 side 3 side, and then closed with an ultrasonic seal, and the sealing layer is placed on the end side in the longitudinal direction, that is, the side facing the funnel 5. is a weak seal layer 44, and the remaining two directions are strong seal layers (not shown). As a result, when the pod 4 is crushed by the developing rollers 25° 26, only the weak sealing layer 44 on the funnel 5 side is torn, and the developing processing solution 50 is transferred to the funnel 5 side, that is, the superimposed photosensitive sheet 1 and image receiving sheet. I try to make sure that everything flows out in the direction of 7 without any waste.

Also, when heat sealing during pod processing, if pod 4
If the outer surface is not covered with the paper layer 40, the sealer bar will directly hit the aluminum layer 41, and the aluminum layer 4
1 to cause a crack. Therefore, the paper layer 40 is bonded to the aluminum layer 41 in advance as a buffer layer using a strong adhesive.

When the pull-out sheet 2 passes through the developing rollers 25 and 26, the pod 4 attached thereto is crushed, so that the jelly-like developing solution flows backward through the funnel 5. This flowed out developing solution is spread by spreading rollers 25 and 26, and becomes uniform in thickness between the photosensitive sheet 1 and the image receiving sheet 7, which face each other via the rails 9 and 10, and is recorded on the photosensitive sheet 1. The negative image is transferred to the image receiving sheet 7 as a positive image. When the photosensitive sheet 1 and the image-receiving sheet 7 are peeled off after a standard peeling time (standard development time), a photographic image can be obtained on the image-receiving sheet 7. Note that the excess developing solution is removed from the skirt 3. Mask 8.
It is captured in a portion surrounded by a pair of plate-like protrusions 11 and 12.

〔Effect of the invention〕

According to the present invention, a pod for enclosing a processing solution is made of a thin sheet laminated with two layers of an alkali-resistant thermoplastic plastic lining layer that can itself be heat-sealed on top of a metal foil. Therefore, the number of pinholes is much smaller than in the case of a single thermoplastic lining layer, which prevents the processing solution from entering the metal foil even during long-term storage, and also Since there is no need to increase the thickness of the plastic lining layer, there is no longer any possibility that a part of the screen may remain undeveloped due to tearing during pod production or an increase in the amount of processing liquid remaining in the pod when it is expanded. In addition, since the two laminated thermoplastic lining layers are of the same type, there is no peeling phenomenon due to heat during heat sealing, and there are no pinholes in the thermoplastic lining layer on the processing liquid side. Even if the treatment liquid enters, it will stop at the surface of the other thermoplastic lining layer, which has excellent alkali resistance, and furthermore, there will be pinholes in the thermoplastic lining layer on the metal foil side, for example near the edges of the sealing part. In this case, since it is melted by heat sealing, it also has the effect of closing pinholes, making it possible to provide a film unit that is safer and can withstand long-term storage.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing essential parts of an embodiment of the present invention. FIG. 2 is a sectional view of a main part of a conventional pod. FIG. 3 is a perspective view showing an embodiment of the present invention. FIG. 4 is a sectional view of the film back. 1... Photosensitive sheet 2...Drawer sheet 4...pod 7... Image receiving sheet 40...Paper layer 41...Aluminum layer 42.43.48...PVC layer. Procedural amendment July 1, 1986

Claims (1)

[Claims] (1) A pod filled with a developing solution is attached, and during development, a developing roller tears the pod apart and pushes out the developing solution sealed in the pod, forming a photosensitive sheet and a non-photosensitive sheet. in an instant film unit which is developed and developed between a metal foil and an alkali-resistant thermoplastic lining layer doubly laminated to the metal foil and heat-sealable as such. An instant film unit characterized in that the thermoplastic lining layer is on the side that comes into contact with a processing solution.