US 3833382 A
Single use rupturable containers or "pods" are disclosed for use in diffusion transfer film units. These pods are particularly adapted for service in film units providing integral negative-positive multicolor reflection prints. The container walls enclosing each fluid retaining cavity are secured together at a plurality of locations within said cavity to assist in the uniform distribution of processing fluid released upon rupture of the pod.
Description (OCR text may contain errors)
United States Patent Land Sept. 3, 1974  Inventor: Edwin H. Land, Cambridge, Mass.
 Assignee: Polaroid Corporation, Cambridge,
 Filed: Dec. 29, 1972  Appl. No.: 319,488
 US. Cl. 96/76 C, 96/29 R  Int. Cl G03c 1/48  Field of Search 96/29, 76 C, 76 R  References Cited UNITED STATES PATENTS 3,221,942 12/1965 Glass 96/76 C 3,589,904 6/1971 Chen 96/76 C 3,603,230 9/1971 Wagner 96/76 C Primary ExaminerRonald H. Smith Assistant Examinerlohn L. Goodrow Attorney, Agent, or FirmSusan M. Cooke  ABSTRACT Single use rupturable containers or pods are disclosed for use in diffusion transfer film units. These pods are particularly adapted for service in film units providing integral negative-positive multicolor reflection prints. The container walls enclosing each fluid retaining cavity are secured together at a plurality of locations within said cavity to assist in the uniform distribution of processing fluid released upon rupture of the pod.
14 Claims, 3 Drawing Figures PHOTOGRAPHIC PRODUCTS INCLUDING RUPTURABLE CONTAINERS This invention relates to fluid carrying containers and, more particularly, to containers adapted to releasably retain a photographic processing composition.
In the photographic processes identified hereinafter, it is often necessary to apply a thin layer of fluid or liquid material over a fairly large surface area. For example, a photosensitive film may be processed by the surface application of a liquid layer containing a silver halide developing composition. Such processing fluids if left in contact with air generally possess a limited shelf life, due in part to degradation of their active components by environmental conditions. Suitable protective containers for releasably retaining them have thus been proposed and patented.
One object of the present invention is to provide a novel container for releasably retaining fluid materials.
Another object is to furnish a container adapted to cause agitation of the fluid contained therein as it is released.
Another object is to provide a rupturable container releasably retaining a photographic processing composition, said container being so constructed as to assist in more uniformly distributing said processing composition.
A still further object is to provide a photographic film unit including a rupturable container which carries viscous fluid for processing said film unit, said fluid being released from said container upon application of compressive force.
Other objects will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the product possessing the features, properties and the relation of components which are exemplified in the following detailed disclosure and the scope of the application of which will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:
FIG. 1 is a perspective view of a sheet of material partly fabricated for use according to the present invention;
H6. 2 is a perspective view of one form of fluid container constructed according to the present invention; and
FIG. 3 is a perspective view, partially in section, of a film unit constructed according to the present inventron.
Containers useful in releasably retaining photographic processing fluids are disclosed in US. Pat. Nos. 2,543,181, 2,634,886 and 2,653,732 among others. Such containers generally comprise a multilayered rectangular blank folded in half longitudinally and secured along the margins of the three unfolded sides to form a central storage cavity. Fluid release is preferentially effected at only the unfolded longitudinal margin by securing its edges less tightly than those on the two side margins. When this rupturable margin is placed adjacent to one side of the surface to be covered by the fluid and the container is compressed, rupture occurs and the fluid contents are released .for application over the adjacent surface area.
concentration of pigment in the fluid spread will render some areas more light reflective than others. This becomes a serious problem when the spread is utilized in a photographic film unit where a light reflecting layer is necessary during processing and/or viewing of the image.
Furthermore, fluid issuing from such a container advances unevenly in a generally tongue shaped front. The nonrupturing margins along the container sides tend to retard rupture at the end portions of the fluid releasing margin. These nonrupturing margins also tend to constrict the adjacent storage area of the container cavity. Upon compression, greater hydraulic pressure is exerted at the unconstricted cavity center where more fluid is stored, promoting initial rupture only at the corresponding center of the fluid releasing side. The tongue shaped fluid front so released may never reach the outer extremities of the area being covered, while the projecting center of this front may advance beyond the area designated for coverage or cause excess fluid accumulation in the center section of the fluid layer which could also result in uneven concentration of pigment, etc. This problem of excess fluid is increased by the greater amount of fluid that is released here from the unconstricted cavity center than is released to side sections of the layer 'from the constricted cavity ends.
To minimize this latter difficulty, the container in US. Pat. No. 3,221,942 utilizes a tighter seal at the center of the fluid releasing side, within the secured margin. This special seal is designed to remain secured when the fluid releasing side ruptures so that it may divert fluid away from the center section toward the outer extremities of the area being covered. Although such a container can release a fluid layer of more uniform thickness and distribution, the fluid still emerges in two large, tongue shaped streams whose sloping sides may result in inadequate coverage of the outer extremities. In an alternative arrangement disclosed in US. Pat. No. 3,603,230, the nonrupturing seal is centrally located within the container cavity to facilitate merging of the streams by the time they have left the container.
This invention provides a rupturable container which mixes the stored fluid upon release from the container and also provides for more uniform fluid distribution.
The container of the present invention may be formed from two substantially rectangular blanks secured together along their outer margins or from a folded blank similarly secured. As with the previously mentioned containers, one longitudinal margin is less tightly secured than the others to provide a preferential site for rupture and fluid release when the container is fluid filled cavity areas, they give the container a quilted" appearance.
Upon container compression and rupture, fluid must pass around these cavity seals to be released. This creates turbulence in and mixing of the fluid. With these constricted areas located throughout the container cavity, the problem of excess fluid stored in the center section is also reduced. Since a substantially equal amount of hydraulic pressure can then be exerted over all the cavity upon compression, initial rupture will occur along the entire length of the fluid releasing margin. In addition, the cavity seals tend to retard rupture at corresponding spots along the fluid releasing margin and thereby act as a counterweight to the rupture retarding effect of the containers side seals. This also promotes the emergence of a linear rather than a tongue shaped front and thus the production of a fluid layer of more uniform thickness and more rectangular distribution.
In most containers the margin at the fluid releasing side is considered narrower in width thanthe cavity. A much greater number of these rows of spaced seals can therefore be accommodated within the cavity than within the margin to provide a more effective means of evenly distributing the fluid. Because several bonding sites are utilized in the present invention instead of only one, accidental rupture at one secured site is less serious. Other secured locations will continue to redistribute fluid in the desired manner.
A rupturable container so designed is especially useful in carrying photographic processing compositions. A latent image formed upon exposure of a photosensitive sheet to actinic radiation may be developed by rupturing the container and distributing its contents between the photosensitive sheet and another superposed sheet, both sheets being generally rectangular in dimension and aligned next to the fluid releasing margin. When the container is positioned so that its contents are adapted to flow between these sheets and the container is compressed, fluid is mixed as it flows around the cavity seals and out of the container. When these seals are evenly spaced apart, a plurality of small, tongue shaped streams emitted from between the seals unite to form a substantially linear front of uniform thickness. Since the front more closely fits the rectangular shape of the area being covered, the amount of excess fluid added to insure complete coverage may be reduced and the amount collected at the end of the processed area is minimized. If an image-receiving layer is included, the processing composition will facilitate transfer of image-forming substances such as those found in silver halide diffusion transfer processes wherein a latent image in the photosensitive element is developed and a positive print of this image is produced at the image-receiving layer.
A preferred embodiment of the container comprises a thin, deformable rectangular blank of several layers, folded medially. as illustrated at in FIG. 1. The container walls preferably possess a thin layer, 11, of material impervious to the processing fluid such as a metal foil of lead, aluminum, etc., approximately 0.001 of an inch thick. Surrounding this layer may be an outer layer, 12, of sheet material suchas kraft paper to limit deformationof container walls. A preferred composition for the innermost layer, 13, is polyvinyl chloride or a similar thermoplastic resin inert and impervious to the processing fluid and its vapors.
The various layers comprising a container wall are laminated together by such means as heat, pressure and/or adhesive. The resultant sheet of material is folded medially and at least its unfolded edges are also secured tgether, as at 20 and 21 in FIG. 2, to provide a fluid retaining container 33. To effect a directional flow of fluid upon rupture, the containers unfolded longitudinal margin, 21, is more weakly secured than the other margins. This may be facilitated by such means as providing a thin strip of thermoplastic material between the opposing margin walls. The side margins 20 may also be provided with stronger ribbed seals. A plurality of spaced cavity seals 22 are provided by securing the opposed walls together at such locations. These cavity seals are preferably formed simultaneously and substantially in the same manner as the end seals 20, as by the application of heat and pressure. In the preferred embodiment at least one row of these seals at evenly spaced intervals is provided intermediate the sealed margins. If more than one row of seals is employed, the seals are preferably offset or staggered for optimum fluid mixing and for better fluid distribution.
The rupturable container of this invention is particu larly adapted for utilization in a film unit such as shown in FIG. 3. Film unit 30 comprises a photosensitive or image-recording sheet, 31, a second or image-receiving sheet, 32, and a rupturable container, 33, holding a quantity of processing fluid, 34. Sheets 31 and 32 are rectangular and may be coextensive with one another, being arranged next to the container in superposed face-to-face contact with at least their lateral edges aligned. These sheets and the container fit within a frame or mask 35, arranged on sheet 32 and extending over the edges of both sheets and the adjacent container to bind them together, the frames rectangular opening defining the area of the image produced in the film unit. The longitudinal fluid releasing margin of container 33 is positioned so as to eject its fluid contents between the facing surfaces of sheets 31 and 32. It is held in place by a strip of material, 36, extending along its fluid releasing margin and the adjacent margin of sheet 31 and within the overlying edge of frame 35. Strip 36 cooperates with the folded under side portions of frame 35 to retain released fluid within the film unit.
Since the processing fluid must remain within the confines of frame 35 throughout processing, it is desirable to minimize the amount of excess fluid accumulated at the opposite or trailing end of the film unit. Any fluid advanced beyond the image area 32 may be stored within a trap area, 37, provided by the folded over portion, 38, of the trailing end of mask 35. An elongated rectangular spacing element, 39, is located within trap area 37 and extends along its length to aid in retaining any excess fluid. Formed of porous material that is substantially incompressible, spacing element 39 maintains separation between sheet 32 and folded over mask portion 38 after compression to provide a trapping space for excess fluid both within and without its pores.
Container rupture and the spreading of released fluid may be carried out by passing the film unit between suitably gapped pressure applying members, such as a pair of cylindrical rollers. When a film unit is advanced between these rollers, container end first, the resulting compressive force generates hydraulic pressure which,
with proper spacing of the quilted cavity seals, ruptures the container along the entire length of its more weakly secured fluid releasing margin or front seal 21. The stored fluid which is mixed as it travels around the cavity seals can then be released in an essentially linear front and spread to a layer of uniform thickness, any excess fluid being accumulated in trap 37.
The rupturable containers or pods provided by this invention are useful in the performance of a number of diffusion transfer image-forming processes. These containers are particularly useful in the production of a positive photographic print, preferably in full color, produced by a diffusion transfer process in which a photographic image-recording medium including a photosensitive material such as silver halide is exposed to form an image (latent) therein and is treated by wetting with a liquid processing agent to develop the image in the image-recording medium, form an imagewise distribution of transferable image-providing substances and transfer the image-providing substances by diffusion to an image-receptive stratum in which they are immobilized to form a visible positive image. The film unit employed in the process may comprise materials for producing a black-and-white print according to a process such as disclosed in the U.S. Pat. of Edwin H. Land, No. 2,543,181, granted Feb. 27, 1951, and No. 2,662,822, granted Dec. 15, 1953; or it may include all of the materials and reagents required to produce a full color photographic print by a process such as disclosed in U.S. Pat. No. 2,983,606, issued May 9, 1961, in the name of Howard G. Rogers. This patent discloses a photosensitive element including a silver halide emulsion and a dye developer, that is, a dye which is a silver halide developing agent; a second or image-receiving element including an image-receiving layer of a dyeable material; and a processing liquid in which the dye developer is soluble. The processing liquid is distributed in a uniform layer between the photosensitive and image-receiving elements with the emulsion and imagereceiving layers in superposed relation. The processing liquid permeates into the photosensitive layer where it initiates development of exposed silver halide. The dye developer is immobilized or precipitated in exposed areas as a consequence of development while in unexposed areas and partially exposed areas of the emulsion the dye developer remains diffusible, thereby providing an imagewise distribution of unoxidized dye developer which is transferred, at least in part, by diffusion to the image-receiving layer without altering the imagewise distribution of the dye developer to form a reversed or positive color image of the developed latent image in the emulsion.
Diffusion transfer film units in which the rupturable container provided by this invention may be utilized generally include two sheet like elements in superposed relationship or adapted to be brought into superposed relationship, with the discharge or front seal 21 so positioned that the released processing fluid is distributed between predetermined surfaces. The film may be of roll film type, pack film type or individual film units (as in FIG. 3). The photosensitive and image-receiving layers may be carried on separate supports or on a common support; in the latter instance, the second sheet like element may serve as a spreader sheet to assist in spreading the fluid. Details of such film structures are well known; for illustrative examples, reference may be made, for example, to U.S. Pat. Nos. 2,543,181; 3,080,805; 3,415,644, and 3,594,164.
Film units where the containers of this invention have found especial utility include those disclosed in the aforementioned U.S. Pat. No. 3,415,644 wherein the image-receiving layer is not separated from the photosensitive element after transfer image formation. In such an arrangement the support for the imagereceiving layer, as well as any other layers intermediate said support and image-receiving layer, is transparent and the fluid processing composition stored in the rupturable container includes a generally insoluble substance, e.g., a white pigment, effective in masking the developed silver halide emulsion or emulsions. Upon compression of the container, this fluid is applied between the image-receiving layer and said silver halide emulsion or emulsions. After diffusion transfer the emulsion(s) is masked by the fluid so that the image may be viewed through the transparent support.
Film units of the type shown in FIG. 3 provide a rigid, durable structure having an integrity which is maintained from the time of assembly (during manufacture) to the finished print. They afford a protective environment for the photosensitive medium as well as the final image, while permitting exposure of the photosensitive medium and viewing of the final image, at least one of the sheets of the film unit being a transparent material. In the embodiment shown the second or imagereceiving sheet is transparent. The photosensitive medium is exposed and the final image is viewed through the image-receiving sheet which functions to protect both the image-recording medium and the final image. (Film units of this type are described in detail for example, in U.S. Pat. No. 3,415,644.) In other embodiments of the film unit the photosensitive sheet may be transparent, depending upon the manner in which the image-recording medium is exposed and the final image is formed and viewed. (Film units of this type are described, for example, in U.S. Pat. No. 3,594,164.)
The embodiment of the film unit illustrated in FIG. 3 is one of the type shown in U.S. Pat. No. 3,415,644 and is adapted to be exposed and processed to produce a multicolor dye transfer image in a dyeable polymeric layer located between a transparent film on which the dyeable polymeric layer is supported and a lightreflecting layer located between the image and the photosensitive layers. This light-reflecting layer comprises a solidified layer of the fluid contents 34 of container 33, the fluid being distributed in sufficient quantity to form such a layer. In order to insure that the quantity of fluid supplied in the container is at least sufficient to form a layer of the desired minimum thickness and extent, the processing liquid is provided in a quantity slightly in excess of the minimum amount required. The processing fluid stored in container 33 comprises an aqueous alkaline solution having a pH at which the dye developers are soluble and diffusible and contains a generally insoluble light-reflecting agent in a quantity sufficient to mask the developed silver halide layers and immobilized dye developers subsequent to processing. Also present is a film-forming, viscosity-increasing agent or agents to facilitate rupture of the container and distribution of the liquid processing composition and help in maintaining the layer of processing composition as a structurally stable layer tending to bind the sheets to one another.
If the film unit is to be processed outside of a camera, an opacification system of the type described in US. Pat. No. 3,647,437 may be provided. In a particularly useful embodiment, the light-reflecting agent, together with suitable optical filter agents, will be present in the layer of fluid spread between the transparent imagereceiving sheet and the opaque image-recording sheet in a concentration sufficient to prevent further exposure of the image-recording medium by actinic radiation transmitted by the transparent image-receiving sheet. Because the silver halide emulsion or emulsions comprising the image-recording strata are thus protected against exposure by incident actinic radiation at one major surface by the opaque processing composition and at the remaining major surface by the opaque support sheet, it is possible to process the film unit subsequent to distribution of the liquid processing composition in the presence of actinic radiation and thereby eliminate the need to provide a processing chamber within the camera and/or make it possible to withdraw the film unit from the camera almost immediately following distribution of the processing composition.
Binding element 35, strip 36, and the material comprising container 33 are also formed of a material opaque to actinic radiation to prevent exposure of the light-recording medium by light entering the laminated assembly at the edges thereof. The light-reflecting agent preferably constitutes about 20 percent to about 50 percent by weight of the processing composition. It is selected for its suitability as a background for viewing the dye image formed in the image-receiving layer as well as for its masking and opacifying properties. Light reflecting agents particularly desirable for incorporation in the processing composition are those providing a white background for viewing the transfer image, particularly those agents conventionally employed to provide a background for photographic reflection prints which have optical properties particularly suited for the reflection of incident radiation. Because of its highly reflective properties titanium dioxide is an especially preferred light reflecting agent.
As is now well known and illustrated, for example, in the previously cited patents, the liquid processing composition referred to for effecting multicolor diffusion transfer processes comprises at least an aqueous solution of alkaline material, for example, sodium hydroxide, potassium hydroxide, and the like, preferably possessing a pH in excess of 12, and most preferably includes a viscosity increasing compound constituting a film-forming material of the type which, when the composition is spread and dried, forms a relatively firm and relatively stable film. The preferred film-forming materials disclosed comprise high molecular weight polymers such as polymeric, water soluble ethers which are inert to an alkaline solution such as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials or thickening agents whose ability to increase viscosity is substantially unaffected if left in solution for a long period of time are capable of utilization. As stated, the film-forming material is preferably contained in the processing composi tion in such suitable quantities as to impart to the composition a viscosity in excess of 1,000 cps. at a temperature of approximately 24 C. and preferably in the order of 100,000 cps. to 200,000 cps. at that temperature. In a particularly useful embodiment, the processing fluid includes a film-forming polymer such as hydroxyethyl cellulose or sodium carboxymethyl cellulose and titanium dioxide; an example of such a processing composition comprises Grams Potassium hydroxide 5. 73 N-benzyl-wpicolinium bromide (50% solution in water) (1]. 23
N-pl1onetliyl-a-picoliuium bromide Hydroxyethyl cellulose (Hercules Type 250M medium viscosity). 'Iit aniuin dioxide Lithium nitrate Bonzotriazole Potassium tliiosulfa Zincnitrato 5methyl-6-bi'on1o-4-azabenzimidazole 0 062 The processing composition is typically applied in a layer having a thickness of the order of about 0.003 to 0.004 inch which is reduced as the solvent, i.e., water, is absorbed to a layer having a thickness of the order of about 0.002 inch. When such processing compositions are distributed from a rupturable container like that shown in FIG. 2, more even distribution of the titanium dioxide is observed due to the turbulence created by the seals 22.
In a particularly usful embodiment of film units such as that shown in H6. 3, the film unit will have an overall dimension of approximately 4.25 by 3.50 inches with an image area approximately 3.14 inches square. The container itself is approximately 3.44 by 0.69 inches with front, back and end margins being approximately 0.09, 0.06 and 0.13. inches wide respectively and the cavity seals measuring approximately 0.03 inches per side. Photosensitive and image-receiving elements 31 and 32 are temporarily laminated together, and spreading of the processing fluid effects delamination between predetermined layers. Reference may be made to US. Pat. Nos. 3,625,281 and 3,625,282, as well as to the copending application of Edwin H. Land, Ser. No. 247,023, filed Apr. 24, 1972, for details of such temporary lamination. Distribution of the processing fluid is facilitated by such a prelamination since Water to make g.
there is little or substantially no air between the sheets to interfere with liquid distribution.
Since certain changes may be made in the above product without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
l. A rupturable, fluid releasing container comprising a pair of substantially rectangular opposing walls, at least one wall being flexible, said walls being secured together along all four margins to enclose a fluid retaining cavity containing a photographic processing composition having an insoluble material dispersed therein, one longitudinal margin being less tightly secured than the other margins to provide a predetermined margin for rupture and fluid release upon compression of said container, said walls enclosing the container cavity being further secured together at a plurality of separate, fluid free seals wholly intermediate said margins.
2. A container as defined in claim 1 wherein the cavity seals intermediate the container margins are formed simultaneously and in the same manner as the sealed margins at either end of the container, said cavity seals being arranged at evenly spaced intervals in at least one relatively centrally situated row extending along the length of the cavity.
3. A container as defined in claim 1 wherein said container walls are formed of a fluid impervious laminate including an inner layer of a thermoplastic polymeric material substantially impervious to said processing fluid.
4. A container as defined in claim 3 wherein said inner wall comprises polyvinyl chloride.
5. A container as defined in claim 1 wherein said cavity seals are arranged in two staggered rows.
6. A container as defined in claim 3 wherein a thin strip of a second thermoplastic material is positioned between the opposed walls forming said less tightly secured longitudinal margin.
7. A container as defined in claim 1 wherein said photographic processing composition includes an aqueous solution of a viscosity-increasing, film-forming polymer and said insoluble material dispersed in said photographic processing composition is a light reflecting pigment.
8. A container as defined in claim 7 wherein said polymer is a cellulose ether and said pigment is titanium dioxide.
9. A container as defined in claim 8 wherein said titanium dioxide comprises about 20 to about 50 percent, by weight, of said composition.
10. A photographic product for forming a diffusion transfer image comprising a photosensitive element, a second sheet like element in superposed relation with said photosensitive element or adapted to be brought into superposed relation with said photosensitive element, an image-receiving layer positioned on one of said elements and a rupturable, fluid releasing container as defined in claim 1, said rupturable container being positioned so that upon compression of said container said fluid will be released for distribution between predetermined layers of said superposed elements.
11. A photographic product as defined in claim 10 wherein said photosensitive element is a multicolor photosensitive element including dye developers as the image-forming materials.
12. A photographic product as defined in claim 11 wherein said second sheet like element is transparent and includes said image-receiving layer, said photosensitive element and said second sheet like element being held in registered, superposed relationship.
13. A photographic product as defined in claim 12, including binding means extending around the edges of said superposed elements, said binding means aiding in retaining and distributing said processing composition following rupture of said container. v
14. A photographic product as defined in claim 13 wherein the cavity seals intermediate the container margins are formed simultaneously and in the same manner as the sealed margins at either end of the container, said cavity seals being arranged at evenly spaced intervals in at least one relatively centrally situated row extending along the length of the cavity.