US2582182A - Apparatus for rapid processing of film - Google Patents

Description

Jan. 8, 1952 3, Mi T T r 2,582,182

APPARATUS FOR RAPID PROCESSING, OF FILM Filed June 26, 1948 INVENTORS T1 .1 CLIFTON M. TUTTLE 1 PARIS H. STAFFORD BY v W q,

ATTORNE S Patented Jan. 8, 1952 APPARATUS FOR RAPID PROCESSING OF FILM Clifton M. Tuttle, Halesite, and Paris H. Stafford,

Huntington, N. Y., assignors to Kenyon Instrument Company, Inc., Huntington, N. Y.

Application June 26, 1948, Serial No. 35,494

6 Claims. 1

This invention has to do with apparatus for processing photographic film which has been exposed. It is an improvement upon apparatus which was developed for rapid processing of photographs of the cathode-ray tube face of a radar system. This apparatus for radar use, including a camera, a processing unit and a projector, came to be known as P 1 and is described in the Journal of the Franklin Institute, vol. 242, No. 3, September 1946, at pages 203 et seq.

In P 1, a strip of film is pulled intermittently along a track within a light-tight housing past a station where the image is produced and where the exposed film is processed, and thence past a station outside the housing where the image is projected, one image being formed and processed while the one previously formed and processed is being projected. The film has its emulsion side uppermost and the exposure is made through the film base by focusing the tube face, located below, through an aperture in the track. The processing cycle may be as short as five seconds.

This rapid action is accomplished by delivering hot chemicals in sequence to the unit which holds them at the film face. In P I this unit is an open plastic cup in the form of two concentric cylinders arranged to drop onto the film from above at the processing station so that thefilm forms the bottom of the cup and a seal is effected-by the lip or rim of the outer cylinder. After each of the hot chemicals (e. g., the developenfixer and wash) has been delivered to the space within the inner cylinder and has had its effect on the emulsion, suction is applied at the space between the cylinders to remove the chemical and to draw air rapidly over the film surface to dry it; whereupon through action of the controlling earns the delivery of the next chemical to the cup is initiated. The whole operation, including film movement and delivery and exhaust of the chemicals and drying air, is controlled by a bank of switches operated by a bank of cams on a single shaft which makes one full turn in the total cycle of about seconds.

The present improvement resides in the film processing unit. It is not limited to use in the P 1 system, or to use for the purposes of that system, but may be used in various systems for various purposes, and especially where it is desired to obtain a photographic image of an object which is in a transient condition (e. g., an oscillograph) or which is better observed in a. photographic image than in its reality (e. g., in photography by infra-red or ultra-violet wave lengths) and where it is desired to process the film with minimum delay in order that the information obtainable from the photograph may be available promptly as a basis for taking a next step. There are also situations where it is desirable to process the film immediately in order to preserve the image against the effects of ambient radiation which would harm the undeveloped image, and the invention is useful in such situations as those, as well as others.

A preferred form of the invention is described below with reference to the annexed drawings, in which:

I Fig. 1 is a view in vertical section through the processing unit proper, with a diagrammatic showing of supply connections for the processing fluids.

Figs. 2 and 3 are, respectively, a plan and an elevation of one of the components of the processing unit.

The film I0 is preferably, but not necessarily,

- in a horizontal plane at the processing station.

In the example shown, the film is at rest at the station; but the only essential is that it be at rest relative to the processin unit. Here the film is shown with the emulsion face at the lower side. The film is moved intermittently by any suitable means to bring successive frames to the processing station.

At this station is a fixed backing support for the film in the form of a disc ll of transparent plastic mounted in a fixed metal ring I! located above the film track and close to the film. This backer presents a fiat surface to the film at one side so that the film can be held fiat against it during the processing.

Below the film is the unit which during the processing forms a chamber that is closed except for the inlet and outlet through which the processing 'fiuids pass under pressure. This unit provides for a continuous fiow of each processing fluid ina confined thin stream across the emulsion face of the film. It also includes means for bringing the parts which form this confined flow passage into working relation with the film, involving a peripheral sealing engagement between the film and the movable member which in conjunction with the film defines the fiow space.

This lower unit consists of two main structural parts, an outer fixed element [5 and an inner movable element l6 sliding in the fixed part so that it can be brought into and out of engagement with the film. The movable element It comprises the parts which define the fiow passage for the processing fiuids. The processing unit shown here also includes pneumatic means for moving the element It into and out of its engagement with the film, certain parts of the fixed and movable elements being so shaped and related that they form two separate piston and cylinder units. one for advancing the inner element |6 under air pressure and the other for retracting it by a suction action. Because of these piston and cylinder features, which preferably are cylindrical, both parts of the processing unit are of cylindrical shape generally; but it will be evident that this shape is not necessary.

Considering the fixed element 1 specifically, it has a main body part I of hollow cylindrical shape with an inwardly projecting integral ring I! giving a smaller internal diameter at the lower part. It has a bottom closure IS in the form of a transparent disc of plastic material which fits within the central bore !9 and has a flange held in a recess 2| by a threaded retaining ring The upper and wider part of the central bore of this fixed element l5 receives the main cylindrical part of the movable element, while the smaller bore afforded by the rin I! receives the depending skirt part 25 of the movable element. Packing rings 21 and '28 seal the joints between the interfitting parts which provide the two piston and cylinder units for actuating the movable element |5.

At one side of the fixed element l5, near its to the central bore is at a point just above the 9 bottom closure l8, thereby admitting air to the space 33 within the depending skirt 26 of the movable element. Because there is a partition (described below) across the interior of the movable member, forming with the skirt 2 6 a piston sliding in the cylinder formed by the inward ring H, the compressed air admitted through passage 32 to the interior space 33 acts on this piston to cause the movable element to move upward toward the film.

At the other side of the fixed element 5 is another nipple 36 similarly threaded into a tap in the wall and giving connection to a vacuum line 31. A passage 38 in the wall of the fixed element leads upward from this tap through the ring I! to the annular space 39 beneath the main body 25 of the movable element and between the outer wall of the skirt 26 and the inner Wall of the fixed element 5. Thus the suction action serves to retract the movable element l6 by its action in this annular piston and cylinder unit formed by these coacting parts.

Near its upper end the movable element I6 has two nipples 4'3, 4| threaded into taps extending through the wall of the main body part '25 at opposite sides. These furnish respectively the connections to the supply line 42 and the exhaust line 43 for the processing fluids, so that flow can be established through the interior chamber 44 in the movable element. This chamber 44 has a bottom closure formed by the transverse partition 45 which is a disc of transparent plastic held in a recess 46 at the lower part of the main body of the movable element by the threaded skirt 25 already mentioned. This bottom closure 45, together with the cylindrical main body part 25, form a cup shaped part the peripheral rim of which engages the film around the area. to be processed to form a fluid tight joint, thereby P 4 forming the main closure for the processing chamber.

Integral with this partition 45 is a block 5|] of transparent plastic which is of smaller lateral size than the interior chamber 44. This block 50 serves as a filler to reduce the free space within the cup shaped part of the movable element, and also serves to further define the flow path for fluids passing from the inlet to the outlet. It extends upward to a plane just short of the plane of the upper rim of the movable element Hi. When the movable element is brought into sealing engagement with the film at the peripheral rim 55, the top face 56 of the filler block 50 is slightly spaced below the emulsion face of the film, and so defines with it a shallow-flow passage across the film face.

The upper rim 55 of the outer cylindrical part 25 of the movable element |5 is tapered to give a narrow surface engaging the film. This gives an effective seal.

To confine the flow of processing fluids to the shallow passage at the film face, between the film and the top surface of the filler block 50, there are vertical fins 57 and 58 at the sides of the filler block 50 midway between the inlet and outlet. These extend into contact with the inner wall of the bore in the movable element and pre vent flow around the side of the filler block while providing some free space in the regions of the inlet and outlet connections to give easy flow to the shallow flow passage across the processing area.

It will be understood that the thin stream flow passage across the film face may be obtained by other forms of construction. This use of an otherwise large chamber with a filler block is, however, a good way of providing wall area suflicient for good inlet and outlet fittings while still obtaining the thin stream flow across the film face which is an important feature of this invention.

It will be noted from the above that all of the transverse parts above and below the film are din transparent, that is, the backer disc it above the film, the filler member 59 and central partition 45 of the movable element It, and the end closure l8 of the stationary element l5. This permits light from a source 59 below the unit to pass through the entire unit, including the thin stream of processing fluid directly under the film, and the film itself to the extent permitted by the film. An optically selective filter 63 may be interposed between the light source and the processing unit to transmit only the desired visible but photographically non-actinic light. If the light source is incorporated in the processing unit above its bottom closure, the latter of course may be opaque.

This provision of a path for light has several purposes which will be better understood from what follows, although it will be evident without more that one result is to make it possible to observe the film during processing.

The chief features of this processing unit are that it provides a hollow member open at one end which intermittently engages the film to form a closed unit, completely sealed, through which the processing fluids may pass, and that at the zone of contact with the film it provides passage for a thin stream of processing fluid passing under pressure in a confined space across the surface of the film. This is the basic idea of means with respect to the processing unit. This is in contrast to the known system mentioned above in which each processing liquid stands in a pool on the film and is withdrawn at the'endofits step-of processing. Within the limit of the requirements of this new idea, the construction may differ from that shown here.

The'further basic feature is the provision of a light path through the unit and across the film station. When used, this requires the use of transparent material for all transverse members between the light source and the outer side of the backing member III, the transparent parts being in register with the film area to be processed and exposing a substantial part or all of that area to the transmitted light.

A processing unit embodying either of these basic improvement features, or the other more specific features here illustrated, may be used with systems of various sorts, manual or automatic, for effecting the delivery and removal of the processing fluids. It may be used for a variety of types of processing; and with the transparent members affording a light path, it may be used for processing color film where a second exposure is made during the processing. I illustrate its use here by reference to a simple processing consisting of these steps in sequence, viz., developing, fixing, washing and drying.

I prefer to pass each processing fluid through the unit in a continuous stream under pressure. To this end a supply of each may be maintained under pressure, as indicated schematically by the containers GI, 62, 63 and 64 for the developer, fixing solution, wash and compressed air, respectively. The liquid containers may be elevated to give a static pressure head, or they maybe subjected to air pressure above the liquid level, or their contents may be force-fed to the unit by a pump or by suction. Lines from each container run to a header 65 or common line leadingto the inlet line 42. In practice there may be such lines leading from supply containers separate from the processing unit, or the processing unit and the containers with their control means may be incorporated in a single housing with internal fiow passages. It is preferable to have as short a fiow as possible from the supply to the processing unit in order to minimize the quantity of each processing fluid remaining in the supply line after its step of processing is completed.

In each supply line is a valve 66, as indicated schematically, which may be operated manually but is preferably operated automatically with a timer or indexing means to cause opening and closing of each valve at the proper time in the cycle. The same cyclingmeans may be used to control the film pull-down and the application of the forces to move the movable element It to and from working position in relation 'to the film.

First, when the film I is advanced to bring a frame to the processing station, the movable element iii of the processingunit is brought into sealing engagement with the film by the pressure of air admitted through line 3|. Then the valve in the line from the developer tank 6| is opened and that liquid fiows over the film face for the desired time. It is continuously discharged to waste through the outlet passage and discharge line 43 which contains a lightly loaded check valve I0 designed to maintain a back pressure of about 3 p. s. i., thus holding the fiuid under pressure at the processing station. At the end of the time necessary for developing, the valve in that line is closed and simultaneously the valve in the line from the fixer supply 62 is opened. The fixing solution then expels the remaining developer steam and continues to flow over the film for the neces-' sary time. By similar valve operation, the wash water (63) follows, and thereafter air (64) is put through to dry the film. The final step is the retraction of the movable element 25 of the processing unit (by suction in line 31 after releasing the pressure in line 3|) and the pull-down of the film to remove the processed frame and advance the next frame to th processing station. If desired, a drying step may be introduced after each step of liquid processing, but this is not always necessary.

In my co-pending application filed herewith, Serial No. 35,493, entitled Control for Rapid Film Processing, I describe a particular system of control which takes advantage of the light path through the processing unit and the varying opacity of the film at different stages of processing to effect a control of the supply valves through a photo-electric cell and electronic relay.

We claim:

1. Apparatus for rapid processing of exposed photographic film, comprising a member presenting a flat supporting surface to the film at one side, a member movable into and out of engagement with the opposite side of the film to hold it against said supporting surface during processing, said movable member comprising a cupshaped part the peripheral rim of which engages the film and forms a fiuid seal therewith around the area of film to be processed, spaced inlet and outlet connections in the side wall of said cupshaped part, and a filler part within said cupshaped part and spaced from its inner surface in the region of the inlet and outlet, said filler part having a transverse surface facing the said supporting surface at a level short of said rim to form with the film a shallow fiow passage across the area of film to be processed, whereby processing fiuids may be passed in sequence from inlet to outlet in a confined thin stream across said film area.

2. Apparatus in accordance with claim 1 in which said supporting member and said cupshaped part and filler have transparent parts forming a light path in register with a substantial part of the area of film to be processed.

3. Apparatus in accordance with claim 1 in which there is a valve associated with said outlet adapted to maintain a predetermined back pressure on a fluid delivered under pressure through said fiow passage.

4. Apparatus in accordance with claim 1 in which there is also a fixed member having a telescopic fit with said cup-shaped port, said fixed member and movable cup-shaped member having cooperating piston and cylinder parts whereby said movable member may be actuated pneumatically.

5. Apparatus for rapid processing of photographic film, comprising a member presenting a supporting surface to the film at one side, a second member having a fiuid chamber, a rim on said second member surrounding the chamber and engageable with the opposite side of the film to form a fluid seal therewith around the longitudinal passages leading along said side wall from said inlet and outlet connections to, Y REFERENCES CITED w I said transverse surface, whereby processing fluids The following references are of record the may be passed in sequence from the inlet confile of this patent: nection along one of the longitudinal passages, and then across the transverse surface in a con- 5 UNITED STATES PATENTS fined thin stream and along the other longi- N mber Name Date tudinal passage to the outlet connection. 2,048,128 Logan July 21, 1936 6. Apparatus according to claim 5, in which 2,221,055 Lundegardh Nov, 12, 1940 the filler part is a removable block having 1ongi- 2,446,668 Tuttle et a1. Aug. 10, 1948 tudinal fins engaging said side wall and defining 10 2,492,133 Cobb Dec. 27, 1949 said passages. I

CLIFTON M. TU'ITLE. PARIS H. STAFFORD.

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