US3418912A

US3418912A - Photographic processing apparatus

Info

Publication number: US3418912A
Application number: US598337A
Authority: US
Inventors: Edwin H Land; Richard J Chen
Original assignee: Polaroid Corp
Current assignee: Polaroid Corp
Priority date: 1966-12-01
Filing date: 1966-12-01
Publication date: 1968-12-31
Anticipated expiration: 1985-12-31

Description

Dec. 31, 1968 5 LAND ET AL 3,418,912

PHOTOGRAPHI C PROCESS ING APPARATUS Filed Dec. 1, 1966 FIG.4

INVENTORS H M 190M 5'. JM

ATTORNEYS United States Patent 3,418,912 PHOTOGRAPHIC PROCESSING APPARATUS Edwin H. Land, Cambridge, and Richard J. Chen,

Winchester, Mass., assignors to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed Dec. 1, 1966, Ser. No. 598,337 11 Claims. (Cl. 95-89) This invention relates to photographic apparatus, and particularly to apparatus for treating photographic sheet material with a liquid to produce a visible image therein. More particularly, the apparatus is designed for treating photographic sheet material with a liquid processing agent subject to deterioration upon contact with the atmosphere while protecting the liquid from contact with the atmosphere.

This invention is particularly useful in conjunction with certain photographic sheet materials for duplicating documents. In the preferred form, the apparatus is designed to contain an aqueous alkaline processing liquid, subject to deterioration upon exposure to the atmosphere, in an open tray or the like and to process, with the aqueous liquid, a succession of exposed photosensitive sheets. The sheets are passed above the tray into engagement with an applicator associated with the tray for applying a predetermined, uniformly distributed quantity of the liquid to each sheet. A relatively non-volatile liquid immiscible with and having a specific gravity less than the processing liquid covers the processing liquid to protect it from contact with the atmosphere, and a barrier is provided to remove the covering liquid from a portion of the surface of the processing liquid adjacent the processing liquid applicator. The applicator comprises a continuous surface which moves from above the covering liquid into the processing liquid and then from the processing liquid, through the portion of the surface of the processing liquid from which the covering liquid has been removed, to apply a portion of the processing liquid to the exposed photosensitive surface of the photographic sheet material.

Heretofore, apparatus of this general type for applying processing liquids have allowed the surface of the liquid to be continuously exposed to the atmosphere and, thus, be subject to deterioration, and/ or have included rather complicated mechanisms for handling the processing liquid so as to limit its exposure to the atmosphere.

It is an object of this invention to provide a novel and improved apparatus for treating photographic sheet material with a liquid processing agent subject to deterioration upon contact with the atmosphere while protecting the liquid against contact with the atmosphere.

Other objects of the invention are: to provide apparatus for applying accurately predetermined and uniformly distributed quantities of an aqueous liquid subject to deterioration upon contact with the atmosphere from a reservoir or body of said liquid to the surface of photographic sheet material and for protecting the body of aqueous liquid from contact with the atmosphere by covering it with a protective layer of another liquid; to provide in apparatus as described for protecting the body of aqueous liquid from contact with th atmosphere by covering it with a second relatively non-volatile liquid, immiscible with and having a specific gravity less than the aqueous liquid; an applicator for transporting the aqueous liquid from below the covering liquid to an exposed photosensitive surface without transferring the covering liquid to the exposed photosensitive surface.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the follow- 3,418,912 Patented Dec. 31, 1968 ing 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:

FIGURES 1 and 2 are diagrammatic sectional views of one embodiment of the coating apparatus of the invention illustrating the operational steps thereof;

FIG. 3 is a sectional view of a second embodiment of the invention; and

FIG. 4 is a sectional view showing another embodiment of the invention.

A number of photographic processes, particularly diffusion transfer processes, involve the treating of a sheet including an exposed photosensitive image-recording material such as silver halide, with an aqueous, alkaline processing liquid including, for example, a silver halide developer, to produce a visible image in the sheet. Most liquid processing agents of this type and particularly those containing alkalis and silver halide developers are subject to deterioration, e.g., evaporation, oxidation, pH changes, etc., when exposed to the atmosphere, so that protection of such liquids from exposure to the atmosphere has posed a problem of long standing.

A light-sensitive, image-recording sheet material suitable for duplicating documents and suitable for use with the apparatus of this invention is disclosed in copending US. patent applications of Edwin H. Land, Ser. Nos. 368,662 and 368,621, filed May 19, 1964. This sheet material comprises, for example, a paper support having a layer of lightsensitive silver halide emulsion and an outer layer comprising a translucent material such as finely divided titanium dioxide, calcium carbonate, magnesium oxide, etc., dispersed in a suitable colloidal carrier or matrix such as gelatin which is permeable to the processing liquid. This outer layer may also contain silver precipitating nuclei and is sufiiciently transparent to permit photoexposure of the light-sensitive layer therebeneath while, at the same time, being sufficiently opaque to provide the requisite background for a positive silver image transferred thereto and to mask the negative image formed thereunder.

An example of the composition of a non-viscous processing liquid suitable for use with the above described photosensitive sheet material is as follows:

Water cc 8400 Sodium sulfite gm 675 Sodium hydroxide gm Potassium thiosulfate -gm 207 4-amino-2, 5-dimethylphenol gm 180 This aqueous and highly alkaline liquid processing agent is obviously susceptible to the heretofore mentioned deterioration upon exposure to the atmosphere.

Reference is now made to FIGURES 1 and 2 of the drawings wherein there is illustrated one embodiment of the apparatus of the invention. The apparatus includes tray 10 for containing a body of the non-viscous, aqueous processing liquid 12 which is protected from deterioration due to contact with the atmosphere by a covering layer 14 of a second liquid floated on the surface of the processing liquid. The covering liquid has a specific gravity less than that of the aqueous liquid, is substantially immiscible with the aqueous liquid, is substantially non-volatile at ordinary temperatures and constitutes a poor solvent for gases in the atmosphere. An example of fluid meeting this criterion is mineral oil, the commonly accepted term used to describe a mixture of hydrocarbons within the viscosity range of products commonly called oils and not volatile at normal temperatures. An example of a particular mineral oil found suitable for use in this apparatus is extra heavy mineral oil produced by E. R. Squibb & Sons having a viscosity of approximately 200 centipoises at 70 F. Mineral oil is particularly desirable because, in :addition to the above enumerated properties, it is relatively inert at least insofar as photographic chemicals are concerned, is colorless, odorless, and any thin coating of the oil remaining on the surface of a sheet following the processing does not tend to become tacky or change color. The depth of the layer 14 is not critical and good results have been obtained for example, with layers of the order of one-eighth inch to one-quarter inch deep.

An applicator roll 16 having a smooth, firm, nonabsorbent, hydrophylic surface stable in both

liquids

12 and 14. Roll 16 is mounted on tray for rotation about the axis of the roll with a portion of the roll periphery submerged in the aqueous processing solution and another portion of the roll periphery extending above the surface of the covering liquid 14. The surface of roll 16 may be of any number of materials; for example, stainless steel or glazed ceramic materials. Rotation of roller 1'6 causes a descending portion of its endless surface to advance from above the covering liquid into the body of aqueous processing liquid 12 and causes an ascending portion of its surface to advance from the processing liquid to above covering liquid 14 for delivering a portion of the processing liquid from beneath the covering liquid to above the covering liquid where it is applied to one side of sheet 18. Scrapers 20 are mounted within tray 10, beneath the interface of

liquids

12 and 14, against the surface of roller 16 along a line substantially parallel to the rotational axis of the roller for removing traces of the covering fluid or contaminants from the surface of roll 16.

Barrier means are provided for maintaining liquid 14 out of contact with the ascending portion of the surface of roll 16. Barrier 22 is pivotally mounted within tray 10 for movement into and out of contact with the ascending surface of roller 16 and comprises a plate having concave surface 24 complimentary to the curvature of roller 16 pivotally mounted on shaft 26 on opposing walls of the tray. The barrier plate is disposed perpendicularly to the walls and the pivotal axis of barrier 22 is parallel to the axis of roller 16. Movement of the barrier away from and into contact with roller 16 establishes and closes a space between the barrier and the roller. The barrier extends from beneath the surface of aqueous liquid 12 to above the surface of covering liquid 14. Edges of barrier plate 22 contact, in a fluid tight manner, the side walls of tray 10 to which the barrier is attached for preventing passage of fluid 14 from one side of the barrier, between the edges thereof and the side walls of the tray, to the area between the barrier and the ascending portion of roller 16. This seal may be effected, for example, by a flexible wiper blade formed of flexible, resilient material such as of polytetrafluoroethylene, mounted along the edges of the barrier plate in contact with the side walls. Barrier 22 may be pivotally displaced from roller 16, as shown in FIGURE 1, to displace liquid 14 and establish a space between the roll and the barrier or it may be positioned with the concave surface 24 of barrier 22 against the complimentary convex surface of roller 16 for closing the space, as shown in FIG. 2.

Mounted above roll 16 is roll 28 having a series of circumferential ridges 30 which press the photosensitive material into contact with applicator roll 16. Roll 28 moves with the direction of travel of the sheet material while applicator roll 16 moves counter to the direction of travel of the sheet material.

Operation of the above described apparatus is as follows: Sheet material 18 bearing an exposed photosensitive area is advanced between rolls 16 and 28 in the direction of arrow 32 so that the exposed area faces roll 1'6. Just prior to movement of material 18 between the rolls, barrier plate 22 is pivoted out of contact with roll 16 to 4 establish a space between the roll and the barrier and to displace covering layer 14. Non-viscous aqueous processing solution 12 then rises in the space between the barrier and the adjacent surface of roll 16. Sheet material 18 is advanced between the rolls and pressed into intimate surface contact with roll 16 by ridges 30 of roll 28. Upon rotation of roll 16 the non-viscous aqueous processing fluid adheres thereto and is transported by the ascending surface thereof from tray 10, past barrier 22 and liquid 14, to the exposed area of photosenstive material 18 which has an affinity for the processing liquid. The relative speed of the exposed surface of sheet 18 and the hydrophylic surface of roll 16 is such that a meniscus 34 of aqueous processing solution 12 is formed adjacent the location at which the two surfaces contact each other. The meniscus establishes a supply of processing liquid for application to the exposed area of sheet 18 as it is advanced between rolls 16 and 28. An exposed area of 8 x 11 inches may require, for example, approximately 1.5 cc. of processing liquid uniformly distributed thereacross. Since the meniscus provides a continuous supply of processing liquid adjacent the location where the surface of roll 16 and a surface of sheet 18 contact each other, uniform distribution of the liquid across the exposed area of the sheet is insured and even amounts thereof are absorbed by every portion of the exposed area. The quantity of liquid applied to the exposed area is dependent upon and controlled by the rotational velocity of roll 16 relative to the velocity of sheet 18.

After contact with sheet 18, the surface of roll 16 diverges from sheet 18 and advances through covering layer 14 into the body of aqueous processing fluid 12. Scrapers 20 remove from the descending portion of the surface of roll 16 any foreign material which may have adhered thereto or any residual coating of fluid 12 which was not previously applied to the surface of material 18. The scrapers also remove from roll 16 any fluid from layer 14 which may have adhered to the surface thereof. It is unlikely, however, that liquid of layer 14 will adhere to the surface of roll 16 if there is a residual coating of aqueous solution 12 on the descending portion thereof due to oleophobic properties of aqueous solution 12,

Barrier 22 is maintained out of engaging relationship with the surface of roll 16 during rotation thereof and fluid 12 is continuously transported from beneath the surface of fluid 14 above the surface of fluid 14 as long as a succession of sheets 18 are being advanced between rolls 16 and 28.

The apparatus also maintains the side of sheet 18 opposite the side thereof bearing the exposed areas substantially free of liquid. The liquid remaining on roll 16 after the trailing edge of the sheet material passes from the rolls tends to be transferred to roll 28 and then applied to said opposite side of the next sheet advanced between the rolls. Liquid allowed to remain on roll 28 will deteriorate and also tend to be transferred by roll 16 from roll 28 back to the body of processing liquid and thereby contaminate the same. Ridges 30 on roll 28, however, insure that only a very small area of roll 28 Wlll contact roll 16 so that only an insignificant amount of the fluid can possibly be transferred to roll 28 and thus to said opposite side of sheet material 18 or back into the body of the processing liquid. Optionally, the surface of roll 28 may be hydrophobic to further inhibit the tendency of the aqueous processing liquid to adhere thereto.

When coating of a sheet is complete, rotation of roll 16 is terminated and barrier 22 is returned to engaging relationship with the surface of roller 16 to prevent exposure to the atmosphere of the aqueous liquid in the space between barrier 22 and roll 16.

Another form of the apparatus embodying the invention is shown in FIG. 3 wherein the same numerals are employed to denote the same parts previouslv shown and described. In this embodiment, roll 16 comprises fluid applying portion 36 and hydrophobic portion 38. Fluid applying portion 36 of the surface of roller 16 is absorbent rather than firm and non-absorbent as is the surface described in the preceding embodiment. Suitable materials for surface portion of roll 16 are oleophobic materials such as wet gelatin or polyvinyl alcohol which reduce any tendency of liquid from covering layer 14 to adhere to portion 36. Portion 38 of the surface of roll 16 is formed of a hydrophobic material such as polyethylene so that it will not transport aqueous fluid 12 above the surface of fluid 14. Materials used for the

surfaces

36 and 38, in addition to other characteristics, must be stable and insoluble in both the aqueous alkaline solution 12 and the layer 14. Roll 40 is mounted above roll 16 for pressing the sheet material into compressive contact with roll 16. The surface of roll 40 is smooth so that compression across the surface of the sheet material will be uniform.

Portion 36 of the surface of roller 16 is of such circumferential length that, considering the length of sheets 18 and the rotational speeds of roller 16, a portion thereof will contact the surface of the sheet along its entire length as the sheet is advanced between the rotating rolls 16 and 40. Portion 38 is of such circumferential length that when the apparatus is not in use it is below the surface of the liquid, out of contact with the atmosphere. If absorbent portion 36 of the surface is exposed to the atmosphere for prolonged periods .of time, liquid 12 absorbed in the sheet is subject to evaporation and deterioration due to contact with the atmosphere, resulting in possible damage to the surface and contamination of the remainder of the body of fluid 12 when the absorbent material containing the deteriorated fluid and/or residue thereof passes into the body of fluid 12.

The surface materials for the roll shown in the embodirnent of FIG. 3 may be relatively soft and, unlike the surface material described for the embodiment shown in FIGURES 1 and 2, may be subject to abrasion. The surfaces of the barrier means and the means for treating roll 16 which contact the surface of roll 16 are thus rotatably mounted to avoid undesirable abrasive contact. Barrier 22 includes roll 42 mounted therein for rolling contact with the surface of roll 16 when the barrier is positioned for contact with roll 16. The roll treating means comprises frictionally driven roll 44 mounted within tray for pressing contact with surface 36 of roll 16 to compress surface 36 for removing therefrom any of either

fluids

12 or 14 held therein. Roll 44 is optional and may be omitted from the apparatus since absorbent surface portion 36 retains enough aqueous liquid to render it oleophobic when it descends through oil layer 14 and since the portion of fluid 12 retained in the. porous surface 36 during operation of the apparatus is not subject to contact with the atmosphere for a suflicient length of time for a significant amount of deterioration to occur.

Operation of this device is as follows: Sheet material 18 having an exposed photosensitive area is advanced to a position between rolls 16 and 40 so that the exposed area faces roll 16. As the leading edge of sheet 18 is advanced into the nip of the rollers, rotation of roll 16 is initiated in a direction counter to the direction of the sheet and barrier 22 is moved out of surface contact with roll 16. The leading edge of the sheet is inserted between the rollers so that the leading edge of the exposed area is in approximate registration with the leading edge of surface portion 36 as it advances from beneath the body of liquid carrying a quantity of non-viscous liquid 12. Since roll 40 uniformly presses sheet 18 into contact with surface portion 36, fluid 22 held in portion 36 is uniformly absorbed therefrom into the sheet 18. As the trailing edge of sheet 18 advances from the nip of rolls 16 and 40, the trailing edge of portions 36 also passes from the nip and the leading edge of surface 38 enters therein. Since portion 38 is hydrophobic, it does not transfer liquid to the surface of roll 40 and thus deteriorated liquid does not contaminate the side of sheets 18 opposite the side bearing the exposed area of the body of liquid. Subsequent to the exit of sheet 18 from the nip of the rolls rotation of roll 16 is terminated when the roller reaches the position wherein surface portion 36 is disposed above fluid 12.

In the embodiment shown in FIG. 4, a movably mounted endless belt is used for applying the processing fluid to the exposed surface of the photographic sheet material. Like numerals have been used to denote parts like those in the embodiments previously described.

Belt 46 comprises liquid applying portion 48 and a non-absorbent or hydrophobic portion 50. Liquid applying portion 48 may include a surface of a hygroscopic material such as polyvinyl alcohol, which will absorb the aqueous processing liquid 12 for transporting the same above the surface of covering liquid 14. The remaining portion, 50, of belt 46 is preferably formed of hydrophobic material such as polyethylene.

Belt 46 is drawn over like

rolls

52 and 54 mounted on tray 10 and over relatively small roll 56 mounted above tray 10. The exposed photosensitive material 18 is fed between pressure roll 40 and moving belt 46 so that the direction and velocity of movement of material 18 is the same as the direction and velocity of movement of the portion of the belt. The length of hygroscopic portion 48 must therefore be equal to the length of exposed area or sheet 18 which is to be treated. The dimensions of the apparatus are such that hygroscopic portion 48 of belt 46 can be maintained beneath the fluid surface when the apparatus is not in use so portion 48 and aqueous processing fluid retained therein will not be maintained above the level of covering fluid 14, in contact with the atmosphere where the liquid will be subject to deterioration. Since such deterioration may be harmful to the aqueous liquid applying surface and residual or deteriorated liquid may contaminate the body of fluid 12 upon entry of the liquid containing portion of the liquid applying surface into the body of fluid 12, and portion of belt 46 is formed of a non-absorbent, preferably hydrophobic material, aqueous processing solution will not adhere thereto and it may therefore be positioned above the surface of the liquid in contact with the atmosphere when the apparatus is not in use.

As in the other embodiments of this invention, barrier 22 extends from above the surface of liquid 14 into the body of liquid 12 and is mounted for movement into and out of engagement with the applicator member.

Operation of the apparatus of FIG. 4 is as follows: Rotation of roll 56 is initiated to drive belt 46 and barrier 22 is moved from engaging relationship with the surface of belt 46. Movement of the barrier establishes a space between the barrier and the belt, displaces a portion of liquid 14 and prevents liquid 14 from moving into the space between barrier 22 and belt 46 in the manner theretofore described. The leading edge of the exposed area of sheet 18 is advanced between roll 40 and belt 46 so that an exposed area faces the belt and the leading edge of the area is in registration with the leading edge of the hygroscopic portion 48 of the belt having a quantity of non-viscous liquid 12 evenly distributed therein. The exposed surface of sheet 18, which is hydrophylic, is pressed by roll 40 into face-to-face contact with aqueous processing liquid bearing portion 48 of belt 46 so that all portions of the exposed surface of photosensi- 18 and portion 48 are in face-to-face contact and thus insure that the correct amount of processing liquid is transfer-red from portion 48 of the belt to the adjacent exposed area of sheet 18. The fluid, when absorbed into the sheet, produces a visible image therein, for example, by a diffusion transfer process.

Belt 46 makes a sharp turn around roll 56 so that its path diverges from the surface of sheet 18. The leading edge of sheet 18 continues to move in its previous direction to be engaged between rolls 58 and guided from the belt. Movement of belt 46 is terminated subsequent to movement of the trailing end of sheet 18 away from the surface of the belt, after hygroscopic portion 48 thereof is advanced to a position wherein it is submerged below the surface of the liquid 12 in tray 10. The leading edge of hydrophobic portion 50 of belt 46 is in registration with the trailing edge of the exposed area of sheet 18 so that as soon as the trailing edge of the sheet passes from between roll 40 and belt 46, roll 40 contacts hydrophobic portion 50 so as to prevent transfer of contaminated liquid to roll 40 and thus to the body of liquid and to the side of sheet 18 opposite the side bearing the exposed area.

When operation of the apparatus is terminated, barrier means 22 is returned to engaging relationship with belt 46 to close the space therebetween so that liquid 12 is not exposed to the atmosphere.

Operation of the apparatus of FIG. 4 may be continuous if means are provided for automatic intermittent advancement of sheets 18 between belt 46 and roll according to the position of belt 46.

This invention thus provides novel and improved apparatus for applying a predetermined, uniformly distributed quantity of a non-viscous, photographic processing liquid subject to deterioration upon contact with the at mosphere, to the surface of a sheet from a body of such liquid while protecting the body of liquid from contact with the atmosphere.

Since certain changes may be made in the above apparatus 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:

1. Photographic apparatus for treating a photographic sheet with a liquid processing agent subject to deterioration upon exposure to the atmosphere, said apparatus comprising, in combination:

an open container for holding a quantity of a processing liquid;

a quantity of a second liquid, substantially non-volatile at normal temperatures, immiscible with and having a specific gravity less than said processing liquid, suificient to form a layer of predetermined thickness on the entire surface of a body of said processing liquid within said container to preclude contact between said processing liquid and the atmosphere;

a applicator member having an endless surface wettable by said processing liquid disposed with a portion of said endless surface located above said second liquid and another portion of said surface located Within said processing liquid;

means for so moving said applicator as to advance a descending portion of said endless surface from above said second liquid downwardly into said processing liquid and advance an ascending portion of said endless surface upwardly from said processing liquid through and from said second liquid;

barrier means extending from above said second liquid into said processing liquid and disposed in contact with said ascending portion of said endless surface to prevent contact between said ascending portion of said endless surface and said second liquid;

means for moving said barrier means from contact with said ascending portion of said endless surface to remove said second liquid from the surface of said processing liquid in the region of said ascending portion of said endless surface; and means for pressing said photographic sheet into contact with a portion of said endless surface exterior of said liquids. 2. The photographic apparatus of claim 1 for use with an aqueous liquid processing agent wherein said endless surface is hydrophilic.

3. The photographicapparatus of claim 1 for use with an aqueous liquid processing agent wherein said endless surface is the outer surface of a layer of hygroscopic material.

4. The photographic apparatus of claim 1 wherein said applicator means is an endless belt.

5. The photographic apparatus of claim 1 wherein said applicator means is a roll.

6. The photographic apparatus as in claim 1 including means within said processing liquid for engaging said descending portion of said endless surface and removing said second liquid therefrom.

7. Photographic apparatus for treating a photographic sheet with a liquid processing agent subject to deterioration upon exposure to the atmosphere, said apparatus comprising, in combination:

an open container for holding a quantity of a processing liquid;

a quantity of a second liquid, substantially non-volatile at normal temperatures, immiscible with and having a specific gravity less than said processing liquid, sufiicient to form a layer of predetermined thickness on the entire surface of a body of said processing liquid within said container;

a generally cylindrical roll mounted for rotation about its axis above the surface of said second liquid with the lower portion of said roll extending through said second liquid into said processing liquid;

means for rotating said roll about said axis;

barrier means extending from above the surface of said second liquid beneath said surface of said processing liquid and disposed in contact with a portion of the surface of said roll extending from above said surface of said second liquid to a location beneath said surface of said processing liquid on the emerging side of said roll to prevent contact between said portion of said roll and said second liquid, said barrier means being movable from contact with said roll to remove said second liquid fromsaid surface of said processing liquid in the region thereof immediately adjacent said portion of said surface of said roll.

8. The photographic apparatus of claim 7 wherein means are provided within said processing liquid for con tacting an axial portion of said surface of said roll on the side thereof opposite said barrier means for removing said second liquid from said surface of said roll.

9. The photographic apparatus of claim 7 wherein said surface of said roll is wettable by said processing liquid and substantially nonwettable by said second liquid.

10. The photographic apparatus of claim 7 useful with a processing liquid including water wherein said second liquid is mineral oil.

11. The photographic apparatus of claim 10 wherein said surface of said roll is oleophobic.

References Cited UNITED STATES PATENTS 3,288,609 11/1966 Land et al 96-50 3,379,113 4/ 1968 Hosoya et a1 -89 NORTON ANSHER, Primary Examiner.

C. E. SMITH, Assistant Examiner.

Claims

1. PHOTOGRAPHIC APPARATUS FOR TREATING A PHOTOGRAPHIC SHEET WITH A LIQUID PROCESSING AGENT SUBJECT TO DETERIORATION UPON EXPOSURE TO THE ATMOSPHERE, SAID APPARATUS COMPRISING, IN COMBINATION: AN OPEN CONTAINER FOR HOLDING A QUANTITY OF A PROCESSING LIQUID; A QUANTITY OF A SECOND LIQUID, SUBSTANTIALLY NON-VOLATILE AT NORMAL TEMPERATURES, IMMISCIBLE WITH AND HAVING A SPECIFIC GRAVITY LESS THAN SAID PROCESSING LIQUID, SUFFICIENT TO FORM A LAYER OF PREDETERMINED THICKNESS ON THE ENTIRE SURFACE OF A BODY OF SAID PROCESSING LIQUID WITHIN SAID CONTAINER TO PRECLUDE CONTACT BETWEEN SAID PROCESSING LIQUID DISPOSED WITH A PORTION OF A APPLICATOR MEMBER HAVING AN ENDLESS SURFACE WETTABLE BY SAID PROCESSING LIQUID DISPOSED WITH A PORTION OF SAID ENDLESS SURFACE LOCATED ABOVE SAID SECOND LIQUID AND ANOTHER PORTION OF SAID SURFACE LOCATED WITHIN SAID PROCESSING LIQUID;