US2769381A - Apparatus for daylight developing, fixing and washing of light sensitive strips - Google Patents

Description

Nov. 6, 1956 M. ESJAK 2 APPARATUS FOR DAYLIGHT DEVELOPING, FIXING AN WASHING OF LIGHT SENSITIVE STRIP Filed NOV. 19. 1951 2 Sheets-Sheet NF/:15 3 E Z 1 *6 INVENTOR:

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HIS ATfORNEYS Nov. 6, 1956 M. LESJAK 2,769,381

APPARATUS FOR DAYLIGHT DEVELOPING, FIXING AND WASHING OF LIGHT SENSITIVE STRIPS- 2 Sheets-Sheet 2 Filed Nov. 19. 1951 INVENTOR. MKIHAEL. LEfiJAIA, DECEASED. By BY EABETTE LEfidAK ExEcu-rmx HIS ATTORNEYS United States Patent APPARATUS FOR DAYLIGHT lNG AND WASHING OF STRIPS Michael Lesjak, deceased, late of Goggingen, Germany,

by Babette Viktoria Lesjak, executrix, Goggingen, Germany DEVELOPING, FIX- LIGHT SENSITIVE The present invention relates to apparatus for develop ing, fixing and washing of light sensitive film strips, particularly roll films, in daylight.

So-called daylight developing tanks have long been known. A very successful type is described in the U. S. Patent No. 2,082,962 issued to the inventor herein and another. In that known type a take-up axle with spirally grooved flanges is provided, the distance between the flanges being such that the edges of the film strip are held within the spiral grooves. Inasmuch as the film is led into the grooves from the inner end of the spiral outwards, a special guide must be provided that presses the edges of the film together sufliciently so that it can be drawn past the flanges to the inner end of the spiral. This guide is swingably mounted between the spirally grooved flanges near the point at which the roll film is drawn into the developing chamber. It is furthermore necessary to provide a pull-in band fixed at one end to the axle and provided at the other end with a clamp for attachment to the leading end of the film. This pull-in band serves the purpose of drawing the end of the film through the guide and into the spiral grooves.

The principal object of this invention is to simplify the above described apparatus by dispensing with many of its parts such as the spirally grooved flanges, the guide and the pull-in band.

In the preferred embodiment of the invention there is utilized the inherent spring action of the film to produce a loose spiral within the developing chamber by winding it up upon a rotatable axle in the developing chamber in the opposite direction to that in which the film strip is compactly rolled upon the usual film spood or in the usual cartridge after exposure. The take-up axle in the developing chamber has substantially straight sides, i. e. it is not provided with the customary spirally grooved flanges, so that edges of the film strip wound thereon are unconfined. This take-up axle bears the film attaching means, thus eliminating the usual pull-in band and clamp. It is further distinguished from the flanged takeup axles of the known apparatus by being rotatable in both directions. This constitutes an important feature of the simplified apparatus.

In operating this apparatus, the film is first wound up upon the axle in the form of a loose spiral with unconfined edges as described above. Thereupon the direction of rotation is reversed and the reverse rotation is continued until the film has become wound upon the axle in the opposite direction. When the direction of rotation is reversed the film is bowed at the axle reversing its direction, and this bow wanders from the inside to the outside of the loose spiral. The movement of this bow helps to agitate the treating liquid, thus insuring rapid and uniform treatment. It is desirable to repeat the successive windings of the film in opposite directions a number of times to insure that the desired treatment such as developing, fixing or washing is complete.

The apparatus may now be described in somewhat greater detail. It consists of the usual developing chamber that may be closed in a light-tight manner by means Patented Nov. 6, 1956 of a cover, but which when so closed still permits filling and emptying of the treating liquid. In the side walls of this container there is centrally mounted a take-up axle provided with a film attaching clamp. This axle is rotatable in both directions and can be actuated from outside the container by means of a protruding button or crank, so that the film that is attached to the axle may readily be wound thereon by drawing it from a preliminary roll film chamber that adjoins the developing chamber near the top. This roll film chamber of the daylight developing tank is separated from the developing chamber by a partition, in order to prevent entrance of the treating liquid. The upper edge of this partition is removed from the take-up axle by a distance that is less than the length of the leading end of the film strip. By leading end is meant that portion of the film strip which is required for introducing it into the camera and upon which, therefore, no exposure can be made. According to this invention the space within the developing chamber should preferably be of such size in relation to the diameter of the take-up axle, that the film strip can be wound successively in reverse directions through its full length upon the take-up axle in the form of a loose spiral. Suflicient clearance should be provided to accommodate the bow that is formed in the film when the direction of the winding is reversed. In order to minimize contact, particularly of the emulsion side of the film, with the walls of the developing chamber and the cover, ridges or like projections are arranged thereon that will permit the film strip to make contact only at its edge zones.

It is preferred to provide a holding device for the film strip, that can be actuated from outside the tank, in the neighborhood of the partition between the roll film chamber and the developing chamber where the film enters the latter. This holding device may be used to prevent the trailing end of the film strip from being drawn into the developing chamber and also makes it possible to treat only a front portion of the film strip. While adequate space must be provided for formation of the loose spiral and of the film bow, the distance between the circumference of the take-up axle and the inner walls and cover of the container in all directions should not substantially exceed the diameter of the take-up axle. Thus it is insured that upon alternate reverse winding of the film, the outermost coil of the film quickly finds support against the inner walls of the developing container and the Wandering film bow formed upon changing the direction of rotation does not deform the film spiral in one direction, but rather wanders uniformly from the inner windings to the outer winding of the spiral while agitating the treating solution in a lively manner.

It is desirable to make the take-up axle removable from the developing chamber to facilitate clamping of the leading end of the film thereto. This may easily be accomplished by providing supports in the side walls that are open at the top and making the actuating knob or handle retractable. Another desirable feature is to provide an indicating device of known construction, in order to be able to determine which length of film has been Wound into the developing chamber. Furthermore, it is easily possible to provide a cutting device for the film between the roll film chamber and the developing chamber.

A particular embodiment of the daylight developing tank in accordance with the invention will now be described with reference to the accompanying drawings in which it is illustrated. Obviously the invention is not limited to the details shown therein. In these drawings: Fig. l is a plan View of the daylight developing tank with its cover removed;

Fig. 2 is a vertical cross section of the daylight developing tank with the cover thereon, showing the leading end of the film clamped to the take-up axle at the beginning of the counterclockwise winding; I

Fig. 3 is the same cross section, however, showing the position of the film in the developing chamber at the beginning of the clockwise winding; and

Fig. 4 is a side view of the daylight developing tank.

In the preliminary roll film chamber 1 adjacent the developing chamber 2' there is placed a roll film spool or cassette 3 and the leading end of the film d is attached to the take-up axle 5 with the aid of the champ 6. The developing chamber is charged with treating liquid 7 either before or after such clamping, and the light-tight cover 8 is placed over both chambers. Upon turning of the crank 9 in a counterclockwise direction, the film is wound upon the axle 5 in the spiral form illustrated inFig. 2. Since such counterclockwise Winding is contrary to the inherent tendency of the roll film to curl in the opposite direction, the film lies about the axle in the form of a loose spiral with unconfined edges. As a counting device there may serve, for example, the measuring roller 14 that is mounted in the neighborhood of the partition 10 between the two chambers and whose teeth grip into the perforations of the film strip. Thus the number of frames that have been drawn into the developing tank may be indicated upon the outside dial 11, for example by means of a Maltese cross-like gear. After the film has been completely wound about the take-up axle 5, the direction of rotation is reversed, and the film is then wound about the axle in a clockwise direction as indicated in Fig. 3. Upon reversing the direction of rotation an S-shaped bow 4a is formed in the inner winding of the film spiral which progressively moves towards the outside and thus facilitates an intimate contact between the treating liquid and the film strip.

In order to make sure that the outer winding of the film strip comes into contact with the walls and cover of the developing chamber only at the edge zones of the film, thus avoiding damage to the picture, the ridges 2a and 8a are provided on such walls and cover which permit contact only at the zones of perforation of the film strip.

It should also be mentioned that the film is preferably held fast in the neighborhood of the partition 10 by means of the holding device 12, before it is wound in the reverse direction (clockwise). This holding device may consist for example of a screw with a rubber head that presses the film against -a projection 1951 on the partition. It is, of course, possible to employ other types of holding devices such as a swingable bow or the like for this purpose. The cover 8 of the developing tank is so formed that it is possible to charge the developing chamber 2 with treating liquid and then to pour out the same through the trough 13 without breaking the light-tight closure.

Thus the developing solution can be replaced by a fixing solution and finally by wash water, so that the development, fixing and washing of the film may be performed successively without removing the film from the developing chamber. If desired the film may be removed after fixing and washed in a stretched condition in the-usual washing vats. After washing, thefilm should be dried in this position. Ifdesired, the take-up axle 5 which is removable may be employed as 'a Weight to hold the film fications may be made of the details described without departing from the spirit and scope of the invention. All such modifications are to be included within the scope of the appended claims unless expressly excluded by the limitations contained therein.

What is claimed is:

1. A daylight developing tank for roll film strips comprising a horizontal preliminary roll film chamber, an adjacent horizontal cylindrical developing chamber for containing a treating solution, a partition between said chambers over whose upper edge the film passes during its transfer from said preliminary to said developing chamber, a light-tight cover for said tank covering both said chambers, a reversibly rotatable axle horizontally mounted in the circular side walls of said horizontal cylindrical developing chamber, said axle including a centrally located groove of a width along said axle at least equal to the width of said film strip, said groove providing a substantially flat clamping surface in a plane parallel to the axes of said axle, a clamping means mounted upon said flat clamping surface for securing the leading end of a film strip to said surface, a holding device mounted through said cover adjacent the upper edge of said partition for securing the trailing end of said film strip to said upper edge of said partition, the distance between the circumference of said axle and the surrounding inner Walls and cover of said developing chamber being substantially equal to the diameter of said axle to insure consistent formation of a wandering bow upon reversed rotations of the axle, and external winding means connected to said axle for rotating said axle to draw the film strip from said preliminary chamber over said partition through said treating solution and when said trailing end of said film strip is secured between said holding device and said upper edge of said partition to form said wandering bow upon reversed rotations of said axle whereby said film strip is agitated through said treating solution.

2. A daylight developing tank as set forth in claim 1 wherein said axle is removably mounted within said cylindrical developing chamber and said winding means is removably connectable to said axle to permit removal of said film and attached axle from said developing chamber to be washed in an unwound elongated condition in a conventional washing vat with said take-up axle being employed as a weight to hold said film strip in said elongated condition.

3. A daylight developing tank as set forth in claim 1 wherein the inner walls and cover of the developing chamber are provided with a pair of ridges spaced to limit the contact of the tank wall to the perforated edge zone of the film to prevent damage to the coated portions of the film.

4. A daylight developing tank as set forth in claim 1 wherein a counting device is mounted within said tank to engage said film at a point between said preliminary chamber and said axle, said counting device extending externally to provide a visible indication of the amount of film unwound within said developing chamber.

References Cited in the file of this patent UNITED STATES PATENTS Orrnond May 29,

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