JPH0687155B2 - Instant film unit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a peel apart type instant film unit.

[Prior art]

A peel apart type instant film unit (hereinafter, simply referred to as a film unit) is a photosensitive sheet on which a negative image is recorded, and this photosensitive sheet are superposed on each other, as described in detail in JP-B-44-2528. It is mainly composed of an image receiving sheet in which the negative image is inverted and transferred to the image receiving sheet. A pull-out sheet is joined to the front end portion of the photosensitive sheet, and a skirt for receiving an excess developing solution is joined to the rear end portion thereof. A developing solution pod and a funnel are attached to the drawer sheet. The funnel guides the developing solution toward the photosensitive sheet and the image receiving sheet while uniformly spreading the developing solution flowing out from the developing solution pod when the developing solution pod is torn by the developing roller. The image receiving sheet is joined to a mask sheet, and the leading end portion of the mask sheet is joined to the drawer sheet.

By the way, the film unit is housed in a film pack, and is exposed after exposing the photosensitive sheet. When pulling out the film unit, first, the tab attached to the pull-out sheet is pulled out so that the front end projects outside the film pack. When the tab is pulled out in this manner, the leading end of the pull-out sheet advances toward between the pair of developing rollers, and the photosensitive sheet is pulled out with this.

On the other hand, since the mask sheet having the image receiving sheet joined to the terminal end side is folded back at its intermediate portion, the image receiving sheet is not pulled out when the tab is pulled out, and the folded back portion is transmitted along the mask sheet itself in the pulling direction. Transitioning. Then, when the folded-back portion of the mask sheet moves in the pull-out direction by a predetermined length, and when the leading end of the pull-out sheet is pulled out through the space between the developing rollers, the tab is peeled from the pull-out sheet. After that, when the leading end of the pull-out sheet is pulled out by hand, the pull-out sheet and the mask sheet, and the photosensitive sheet and the image receiving sheet are pulled out from between the developing rollers while sequentially overlapping. Immediately before the photosensitive sheet and the image receiving sheet are overlapped and pulled out, the developing solution pod is cleaved so that the developing solution is spread between the photosensitive sheet and the image receiving sheet. Transfer development is performed by superposing and drawing out from the developing roller.

[Problems to be solved by the invention]

By the way, when the instant film unit configured as described above is used, the tab is often pulled out obliquely in the in-plane direction of the film unit. In particular,
When the pull-out angle is about 15 °, the pull-out resistance does not become extremely large, and the pull-out can be performed normally. When the tab is pulled out obliquely in this way, the pull-out end of the pull-out sheet is also obliquely indexed from the film pack. Then, when the pull-out end is pulled out from between the developing rollers after that, even if the pull-out end is pulled straight, the photosensitive sheet and the image receiving sheet are not correctly overlapped, that is, they are pulled out with misalignment. When such misalignment occurs, a misalignment occurs between the screen position exposed on the photosensitive sheet and the screen frame of the image receiving sheet, and a part of the photographic image to be transferred to the image receiving sheet is lost. Comes out.

The present invention has been made in view of such a conventional technique, and even if the tab is pulled out at an angle,
An object of the present invention is to provide an instant film unit in which a screen cut due to misalignment does not occur.

[Means for solving problems]

In solving the above problems, as a result of first analyzing the action of the conventional instant film unit, it was found that the above-mentioned misalignment is mainly due to the following causes.

That is, in the conventional instant film unit, the photosensitive sheet, the image receiving sheet, and the drawer sheet and the mask sheet have almost the same width according to the inner direction of the film pack so that there is no play in the lateral direction inside the film pack. It has become. Therefore, in the process in which the tab is pulled out obliquely, when the folded portion formed in the middle portion of the mask sheet moves in the pulling direction, this portion rubs against the inner surface of the side wall of the film pack. When the folded portion of the mask sheet rubs against the inner wall of the film pack in this manner, a strong crease is formed at that portion.

When the crease is made in the middle part of the mask sheet in this way, the waist becomes stronger at that part, and after the tab is peeled off, the crease part does not spread when pulling out both the photosensitive and image receiving sheets with the tip of the drawer sheet. It will be pulled out as it is. As a result, the total length of the mask sheet becomes shorter than the planned length, and the photosensitive sheet and the image receiving sheet do not properly overlap each other when passing through the developing roller.

In order to solve this, if the width of the film pack is increased and a play is provided in advance between the mask sheet and the inner wall of the film pack, this play adversely affects when the film unit itself is pulled out, Both sheets will not overlap properly. If the mask sheet material is made of a material that is sufficiently weak, even if the mask sheet has a crease, the image receiving sheet is braked by the pack sponge, so that the image receiving sheet is not pulled out. The fold line is stretched in the direction, and the above-mentioned phenomenon is less likely to occur. However, the mask sheet is required to have tensile strength, and further, as the size of the film unit increases, its strength also needs to be increased, so there is a limit to making it thin and supple,
The above-mentioned problems cannot be solved only by selecting the material of the mask sheet, and the fact that a lubricant is applied to the surface of the mask sheet has practically no effect.

In view of the above findings, the instant film unit of the present invention has a folded portion formed in advance along with the withdrawal of the intermediate portion of the mask sheet in which the leading end side is joined to the drawing end and the image receiving sheet is joined to the terminal end side, that is, the tab. Regarding the range in which the parts are moved, the lateral width is configured to be narrower than the lateral width of the drawer sheet.

[Action]

In this way, if the width of the middle portion of the mask sheet is made narrower than the width of the pull-out sheet, there is a margin between this portion and the inner surface of the side wall of the film pack. Therefore, the tab is pulled out obliquely, and the folded-back portion formed in the intermediate portion of the mask sheet is
Even if it is transferred to one side wall of the film pack while being biased, it does not interfere with the inner surface of the side wall of the film pack and rub against it. As a result, no strong creases are formed in the middle portion of the mask sheet, so that the folded portion of the mask sheet is smoothly moved in the pull-out direction, and the image receiving sheet is pulled out after the mask sheet is properly spread. It is a thing.

Hereinafter, the present invention will be described in detail with reference to the drawings.

[Structure of Invention]

Referring to FIG. 1 showing a film unit embodying the present invention, a photosensitive sheet 1 has a drawing sheet 2 joined to the front end side thereof, and a short skirt 3 for receiving an excess developing processing solution joined to the rear end side thereof. ing. The drawer sheet 2 and the skirt 3 are made of carbon-mixed paper in order to eliminate surface reflection. The drawer sheet 2 includes a development processing solution pod 4 containing a development processing solution.
And a funnel 5 that guides the developing solution toward the photosensitive sheet 1, and a tab 6 is joined to the tip end side of the funnel 5 through a joining portion 6a.

The image receiving sheet 7 is for recording a final photographic image, and is joined to the mask sheet 8 via a weak seal layer. The mask sheet 8 has an opening 8a corresponding to the screen size, and its tip is joined to the drawer sheet 2. A band-shaped cutout portion 8b having a width of about 2 mm is formed on both side edges of the intermediate portion of the mask sheet 8, that is, between the joint portion with the pull-out sheet 2 and the joint portion with the image receiving sheet 7. Therefore, the width of the mask sheet 8 is
Width of drawer sheet 2, photosensitive sheet 1, image receiving sheet 7 (approx.
It is about 4 mm narrower than 102 mm).

On both sides of the opening 8a formed in the mask sheet 8, band-shaped rails 9 and 10 made of relatively thick paper are adhered. At the rear ends of the rails 9 and 10, a space for accommodating the excess developing solution is secured, and in order to prevent the excess developing solution from being pushed out by a developing roller described later, it is made of hard plastic. Individual plate-like projections 11,12
Are glued together.

FIG. 2 shows a state in which the film unit is loaded in the film pack. The film pack 20 is loaded with 10 film units in monochrome, but only one is shown to simplify the drawing. The film pack 20 is composed of a pack main body 21 having a front lower portion and a bottom opening, and a film pressure plate fitted in the pack main body 21.
22 and a bottom plate 23 fitted to the lower part of the pack 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. Then, the tab 6 projects from the film pack 20 so as to come on the pair of developing rollers 25 and 26. It should be noted that what is indicated by the chain double-dashed line is the tab 29 of the second film unit, and the portion of which the tip is bent is adhered to the tab 6.

An exposure window 21a is formed on the upper surface of the pack body 21, and the photosensitive sheet 1 is exposed by light passing through the exposure window 21a.
The film pressure plate 22 includes a flat plate portion 22a and leg portions 22b provided on both sides thereof. In the plate portion 21a, the skirt 3 is temporarily fixed to the inclined front end portion by the staple 27, and the rear end portion is curled to guide the drawer sheet 2 and the photosensitive sheet 1. The bottom plate 23 is provided with a spring plate 23a for pushing up the leg portion 22b of the film pressure plate 22, and a sponge plate 28 for pushing up the image receiving sheet 7 is attached.

After exposing the photosensitive sheet 1, the film pack
When pulling out the film unit from 20, the tab 6 is first pulled out by hand, which causes the leading edge of the pull-out sheet 2.
2a is pulled out. At this time, the folded-back portion 8c (see FIG. 1) of the mask sheet 8 is moved in the pull-out direction while changing the folded-back position. And the mask sheet 8
Moves toward the exit of the film pack 20 while gradually reversing from the leading end side and overlapping the drawer sheet 2. Further, the photosensitive sheet 1 is guided by the rear end of the film pressure plate 22, and wraps around the back of the film pressure plate 22 to be reversed. Tab 6
Is pulled out from the upper side of the developing rollers 25 and 26, so that when the leading edge 2a of the pull-out sheet 2 slightly goes out between the developing rollers 25 and 26, the joint portion 6a at the rear end of the tab 6 is wedged in the developing roller 25. By the action, it is peeled from the drawer sheet 2.

Next, if the leading end 2a of the pull-out sheet 2 is grabbed by hand and pulled out, the pull-out sheet 2 and the mask 8 first pass between the spreading rollers 25 and 26 with the mask 8 overlapping, and then the photosensitive sheet 1
And the image receiving sheet 7 overlap each other and pass between the developing rollers 25 and 26. The pull-out sheet 2 is the spreading rollers 25, 26.
Processing solution pod 4 attached to it when passing through
Is crushed, the developing solution in the form of jelly flows backward through the funnel 5. The developing solution that has flowed out is developed by the developing rollers 25 and 26, and the rails 9 and 10
The negative image recorded on the photosensitive sheet 1 is transferred to the image receiving sheet 7 as a positive image with a uniform thickness between the photosensitive sheet 1 and the image receiving sheet 7 facing each other. When the photosensitive sheet 1 and the image receiving sheet 7 are peeled off after the standard peeling time (standard developing time), a photographic image can be obtained on the image receiving sheet 7. The excess developing solution is stored in the excess developing solution storage chamber surrounded by the skirt 3, the mask sheet 8, and the pair of plate-shaped projections 11 and 12.

In the drawing operation of the film unit described above, the third
As shown in the figure, when the tab 6 is pulled out obliquely from the pack main body 21 as indicated by an arrow A, the leading end 2a of the drawer sheet 2 is obliquely indexed. At the same time, one end of the mask sheet 8 joined to the leading end side of the pullout sheet 2 is also pulled diagonally leftward. As a result, the folded portion 8c of the mask sheet 8 approaches the side wall inner surface 21b of the pack body 21.
However, as described above, the cutout portion 8b is provided in the middle portion of the mask sheet 8, and the lateral width thereof is narrower than the lateral width of the drawer sheet 2. Therefore, the drawer sheet 2
Even when the side edge of the mask sheet 8 slidably contacts the inner surface 21 of the side wall, the folded-back portion 8c of the mask sheet 8 does not slidably contact the inner surface 21 of the side wall, and no crease is formed at this portion.

After the tab 6 is peeled from the pull-out sheet 2, the developing roller
The tip 2a of the pull-out sheet 2 protruding from between 25 and 26
Pull out by hand. FIG. 4 shows a development view of the film unit thus drawn out from the back side of the image receiving sheet 7. However, the image receiving sheet 7 is correctly formed as the photosensitive sheet 1 because no crease is formed in the middle portion of the mask sheet 8. It is not aligned and the screen is not cut off. The length of the excision portion 8b is set so as to prevent the development processing liquid from leaking and prevent the mask sheet 8 from being leaked.
It is preferable that the rear end side thereof does not reach the joint portion with the image receiving sheet 7 so that the strength of No. 1 does not become weak.

By the way, in the case of the conventional film unit, the tab 6
Since the side edges of the mask sheet 8 are strongly rubbed against the inner wall surface 21b of the side wall of the pack body in the process of pulling out diagonally, the strong creases 30 are formed in the mask sheet 8 as indicated by the chain double-dashed line in FIG.
Is attached. Therefore, the total length of the mask sheet 8 becomes short on the side where the fold line 30 is formed, and when the mask sheet 8 is pulled out, the image receiving sheet 7 does not properly overlap with the photosensitive sheet 1 and the screen is cut off as shown by the chain double-dashed line. It will be invited. Such a failure may cause tab 6 to
When pulled out at an angle, the conventional film unit
About 5 to 10 out of 100 sheets were generated, but as described above, the cutout portions 8b with a width of about 2 mm are provided on both sides of the intermediate portion of the mask sheet 8.
As a result of the formation of the above, these failures no longer occur. In addition, in order to narrow the intermediate portion of the mask sheet 8,
As shown in FIG. 5, oblique cutouts 31 may be formed on both side edges of the intermediate portion.

〔The invention's effect〕

As described above, in the instant film unit of the present invention, by forming the lateral width of the intermediate portion of the mask sheet on which the folded portion is formed to be narrower than the lateral width of the drawer sheet, the side edge of the intermediate portion is formed. A space is provided between the film pack and the side wall.
Therefore, even if the tab is pulled out at an angle and the drawer sheet is pulled out at the same time, the middle part of the mask sheet rubs against the side wall of the film pack during this time and a strong crease is made in this middle part. Disappears.
As a result, the image receiving sheet is pulled out after the mask sheet is completely unfolded without any creases, so the image receiving sheet and the photosensitive sheet enter the spreading roller in the state of being correctly overlapped with each other, resulting in a screen cut failure due to misalignment as in the past. Will certainly be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of the film unit. FIG. 2 is a sectional view showing a state in which the film unit is loaded in the film pack. FIG. 3 is an explanatory view showing a state in which the tab is pulled out obliquely. FIG. 4 is a development view of the instant film unit pulled out from the film pack. FIG. 5 is a development view of a film unit showing another embodiment of the present invention. 1 ... Photosensitive sheet, 2 ... Drawer sheet, 4 ... Development processing solution pod, 6 ... Tab, 7 ... Image receiving sheet, 8 ... Mask sheet, 8b ... Cutting section, 8c ... Folding section, 9, 10 ... Rail 20 …… Film pack 25,26 …… Developing roller.

Claims (1)

[Claims] 1. A drawer sheet having a tab joined to one end and a photosensitive sheet joined to the other end, and a mask sheet having one end of the drawer sheet joined to the leading end and an image receiving sheet joined to the trailing end. In the instant film pack, wherein the pulling-out end is pulled out to the outside of the film pack while the folding-back part formed in the middle portion of the mask sheet by pulling out the tab is moved to the pulling-out side, the folding-back part is formed. An instant film unit characterized in that the width of the middle portion of the mask sheet is made narrower than the width of the drawer sheet.