US3595156A

US3595156A - Equipment for developing photographic film

Info

Publication number: US3595156A
Application number: US765236A
Authority: US
Inventors: Walter Zimmermann
Original assignee: MESSRS MAFI FIEDLER AND ZIMMERMA
Current assignee: MESSRS MAFI FIEDLER AND ZIMMERMA
Priority date: 1967-10-06
Filing date: 1968-10-04
Publication date: 1971-07-27
Anticipated expiration: 1988-07-27

Abstract

Equipment is disclosed for holding a film closely adjacent a rotating cylinder having external ribs for agitating the developing fluid close to the film surface which is held stationary between cams to attain a semicylindrical configuration. A half cylindrical tank is pivotable for holding the developing fluid and discharging it when tipped. For color processing a plurality of similar equipments has controls and programming means including separate valves for introducing fluids at specified times and for simultaneously discharging all tanks.

Description

United States Patent EQUIPMENT FOR DEVELOPING PHOTOGRAPHIC FILM References Cited UNITED STATES PATENTS 8/ I 960 Faeber 5/1966 Lasar.. 12/ l 966 HallQuist FOREIGN PATENTS SH 965 Germany ABSTRACT: Equipment is disclosed for holding a film closely adjacent a rotating cylinder having external ribs for agitating the developing fluid close to the film surface which is held stalochims's Drawing Figs tionary between cams to attain a semicylindrical configura- U.S.Cl 95/89, ion. A half cylindrical tank is pivotable for holding the 95/96, Il8/6l2, 259/45 4 developing fluid and discharging it when tipped. For color Int. Cl 603d 3/00 processing a plurality of similar equipments has controls and Field of Search 95/89, 95, programming means including separate valves for introducing 96, 97, 98, 94, 93, 99, 90.5; 1 18/612, l9; 259/45, fluids at specified times and for simultaneously discharging all I 46 tanks.

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SHEEI 1 OF 2 FIG 3 Fl 6.4

INVEN TOR.

EQUIPMENT FOR DEVELOPING PHOTOGRAPHIC FILM This invention relates to equipment for developing layered photographic film carrying emulsion, and more particularly to equipment for processing color film.

In the development of photographic film carrying emulsion where the film is held stationary, the light sensitive layer of silver-bromide is reduced to silver with the bromide going into solution. This bromide weakens the activity of the developing fluid and must be quickly carried away from the film emulsion surface to prevent clogging or streaking in the development. Although the problem that quickly disposing of the portions plays during the processing is commonly known by the film makers and amateur processors, significant problems have been imposed in adapting the technique for commercial processing particularly in color development. It has been determined that in conventional automatic or semiautomatic developers with a vat emptyable such as by a pipe, the film has so-called bromide stripes in the form of dark regions appearing during the developing process on lightly or rioncxposed light sensitive film locations as a result of developer flowing from heavily exposed regions. These bromide streaks do not permit first class reproduction and prevent sharp contrast at bordering regions. A remedy for these streaks has been sought resulting in reversibly moving the film through a moving developing fluid. For this purpose also, either the same developing process with a mechanically driven wobbleplate or a developing fluid having an inactive gas such as nitrogen blown through it have been employed. None of these methods has achieved successful results. For this reason it has been necessary in the prior art to use manual developing tanks in order to produce color film of adequate high quality. In this respect the possibility exists through the necessary motion of the tank and/or the film in optional patterns and speeds to move the developing fluid over the film in such places as noticed or in places with sharp dark-light borders to flush the traces away. This is a specialized art requiring expert and trained professional people. It can be observed from the shortages of this kind of skilled technicians and the considerable cost of the one-at-a-time development that the manual developing process has great disadvantage, and that the best workman himself cannot succeed in making an entire series of prints with exactly the same contrast. Also the chemical process of development from halftone negatives iscritical to a great degree, as a result not only of the developer but the time and temperature and also the motion, whereby with the manual one-at-a-time development it is extremely difficult to produce in exactly the same quality either a series of black and white or color reproductions. Finally it has become necessary to change the emulsion carrier for commercial color development, which to satisfy the four dominant methods available was formerly made with a hard surface that resisted scratching of the light sensitive layer during processing to conform with manual processing or to make possible mechanical processing if it should become available.

An object of this invention therefore is to effect develop ment of a layered photographic emulsion carrier by a process which reduces as much as possible the mentioned traces and which permits handling of the film in a mechanism without scratching the emulsion.

As a consequence of the invention this objective is attained by placing as close as possible to a motionless emulsion carrier film a device cyclically moving the developing fluid to produce agitation which results in the flushing movement of the expended fluid portions to the edge of the film. Through the action of the agitation pattern the impurities from the light sensitive layer are displaced and moved to the edge of the film so that they cannot any longer come in contact with the emulsion layer. Unexpectedly good results are possible if the fluid is alternatively flushed in two diagonal directions across the emulsion carrier.

Apparatus illustrating the process afforded by this invention produces a displacement of the developing fluid with a cyclic motion effective very close to the surface of the emulsion. It is evident that with this sort of developing process mechanical equipment is possible, where the flushing process is motor driven. This is exemplified in apparatus comprising a semicylindrical developing tank in which an emulsion carrying film is supported by cams alongside a rotatable cylinder for displacing the developing fluid by means of agitating ribs on the surface of the cylinder held close to the film. When the cylinder is turned the agitation forms a whirlpool or eddy pattern very close to the film which forces the developing fluid components toward the edge of the film.

For this purpose the ribs are arranged at an angle on the surface of the cylinder so that they stroke the film with diagonal lines. In one embodiment two ribs are arranged in a mirrorimage fashion with respect to an intermediate line on the cylinder surface. Experience has proven with this embodiment of the invention where the ribs are stroked across the film alternately in both diagonal directions that an especially impurity trace free process is attained.

For conventional color reproduction four steps are used. In order to proceed with these four steps simultaneously, as provided by the invention, four similar developing tanks are arranged with each tank having flushing means driven in the same cyclic pattern and at the same velocity. In this way it is guaranteed that the developing time and agitation can be performed always under identical conditions. This embodiment is especially suitable for replacing the one-at-a-time development with the evident advantage of labor saving. In this example, four semicylindrical tippable developing vats are provided, that are controlled by a single tipping mechanism for emptying simultaneously and by a set of individual input valves for filling as desired, wherein a single drive motor drives the cylindrical liquid displacement means. For the purpose of automating this developing process the motor can drive a programming device controlling the tipping mechanism and the input valves.

Further advantages, objectives and novel features of the invention are found throughout the description, drawings and claims. In the drawing typical embodiments of the apparatus illustrating the invention are set forth, wherein:

F IG. 1 shows in front view the essential portions of developing equipment embodying the invention,

F IG. 2 is a side section view of the apparatus in FIG. 1,

FIG. 3 is a developed view of the surface of the rotatable cylinder of the apparatus in FIGS. 1 and 2,

FIG. 4 is a developed view of a modified cylinder surface, and

FIG. 5 is a schematic diagram of developing equipment for color reproduction.

The apparatus of FIGS. 1 and 2 shows a half cylindrical developing tank 10, tiltable inside vat 11 which is supplied with outlet 11a. The tilting tank 10 on its inner surface is supplied with four cams 12 with constrictions 13, between which is spanned in a circular arc the emulsion carrier 14 to be treated with the emulsion side held toward the tank opening. A cylindrical drum 15 is coaxially mounted in tank 10 by means of pivot shaft 16. The pivot shaft mounting framework is schematically shown by members l7, l8 and 19.

On the outer surface of cylinder 15 and generally longitudinally directed are two

similar ribs

20, 21. In one embodiment of FIG. 3, illustrating the developed view of the surface of the cylinder 15, the

ribs

20, 21 slant in mirror image form from the mid line B running through the surface. The pitch angle of the

ribs

20, 21 is so chosen to lie parallel to and at the same time diagonal to the emulsion carrier 14.

The equipment works in the following manner: When the developing tank 10 is dry, the emulsion carrier 14 is laid therein to be held between cams 12. Then the tank 10 is filled with developing fluid and the cylinder 15 is started rotating. For example the cylinder 14 is turned by means of an electric motor (not shown). As a consequence of the turning of the cylinder 15 the

ribs

20 and 21 stroke one after the other diagonally over the emulsion carrier 14 in close spacing, such as l or 2 millimeters. Accordingly the ribs produce a whirlpool in contact with the outer surface of the light sensitive layer at the developing position and flushes the agitated liquid portion directly thereover diagonally with the edge of the emulsion carrier. in this manner the bromides are satisfactorily moved away from the light sensitive layer and are kept from settling on another portion of the layer. It can be recognized that the liquid displacement means provided with flushing ribs in the equipment afforded by this invention for developing emulsion carrying film is novel.

The driving of cylinder 15 can proceed at predetermined uniform cyclic speed or can be of variable speed either in one direction or reversible directions. Also the elongated ribs on the cylinder 15 can be modified as in the embodiment of FIG. 4 where the further

auxiliary ribs

22 and 22 are shown.

After termination of the chosen developing period the cylinder 15 may be stopped and the tank emptied by tipping, whereby the developing fluid flows into tray 11 and through outlet 110. Then the emptied tipping tank 10 in a similar manner can be filled with a stop bath and afterward a fixing fluid. It is especially desirable if the cylinder is also turning when the stop bath is found therein. In other words the cylinder 15 can remain rotating as long as the process proceeds.

ln HO. 5, apparatus adapted for color reproduction is shown schematically, in which four sections are necessary. The apparatus comprises four similar side by side tippable tanks 10 with ribbed cylinders 15, wherein the tanks and cylinders are constructed as set fonh in FIGS. 1 through 3. Each of the four tippable tanks 10 has over it an individual filling tube connected with a magnetic valve 23 and a storage tank 24 for developing fluid, and if desired also with further tanks for the stop and fixing liquids. The emptying of tanks 10 results from a common tipping mechanism 25, that is driven from one side by a motor. The ribbed cylinders 15 are set into rotation by drive wheels 26 from a motor (not shown). A programming device 27 controls the magnetic valves 23 and the drive motors for the cylinders 15 and the tipping tank mechanism 25.

With the apparatus it is possible to provide in each of the four sections a definite developing time and a definite developing rate each in accordance with the setting of the respective section. By means of the four individual magnetic valves 23 each of the tilting tanks can be filled at exactly the proper time to establish the appropriate development procedure. The agitation of the developing fluid proceeds dur' ing the development process simultaneously for all four tanks 10, and they are emptied together. By means of the program device 27 this process can be automatically and exactly reproduced, so that production of a series of operations in short time and with fully controllable quality is possible.

The apparatus shown in H6. 5 also makes possible the use of little labor in the process of color reproduction, and for the reason that the independent choice of developing fluid for each of the four tippable tanks exists, a very small batch of the developing fluid is used. Efficient use of time is assured by the employment of the very advantageous simultaneous developing process made possible by regulating the introduction and consumption of the developing fluid.

What I claim is:

1. Apparatus for the development of layered photographic emulsion carrier films, especially for the process of reproducing color comprising in combination, a tank with an upper opening holding a developing fluid, means holding a photographic film motionless in said tank under said developing fluid with the emulsion side held toward the tank opening, cyclic means moving in said developing fluid with a predetermined repetitive rhythmic motion including means mounting the cyclic means in place closely adjacent said film without touching at a spacing in the order of 2 millimeters, and agitating means comprising members working in conjunction with said cyclic means providing an eddy effect in the developing fluid flushing it toward the edge of the film.

2. Apparatus as defined in claim 1 wherein the agitating means members are disposed so as to flush the developing fluid in two diagonal directions toward the edge of said film.

3. Apparatus according to claim 1 including semicylindrical tank means holding the developing fluid adjacent said cyclic means and means for pivotally mounting the tank to tip it and discharge the fluid.

4. Apparatus as defined in claim 3 with said tank means having shoulder members therein for retaining the film in half cylindrical disposition, and wherein the cyclic means is a rotatable cylinder having ribs on its outer surface.

5. Apparatus as defined in claim 4 wherein the ribs are oriented to stroke the film diagonally.

6 Apparatus as defined in claim 5 having two slanting ribs disposed in mirror image form on opposite sides of a center line.

7. Apparatus as defined in claim 3 and comprising a plurality of similar devices arranged so that the cyclic means are driven commonly from a single drive motor.

8. Apparatus as defined in claim 7 including discharge means to empty all the tanks in unison.

9. Apparatus as defined in claim 8 including separate valve means for each device for discharging liquid into the respective said tank means.

10. Apparatus as defined in claim 9 including programming means for controlling the valve means and the discharge means.

Claims

5. Apparatus as defined in claim 4 wherein the ribs are oriented to stroke the film diagonally. 6 Apparatus as defined in claim 5 having two slanting ribs disposed in mirror image form on opposite sides of a center line.