US3640205A

US3640205A - Apparatus for wet treatment of photographic films or the like

Info

Publication number: US3640205A
Application number: US31287A
Authority: US
Inventors: Fritz Waschk; Jurgen Muller; Heinrich Krieger; Gunter Heindrich
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1969-04-25
Filing date: 1970-04-23
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: DE6916867U

Abstract

A vessel which contains a supply of treating fluid for webs of photographic films or the like accommodates a guide having a concave upper surface along which a web advances lengthwise to be thereby immersed into the liquid and to continuously withdraw some liquid which is thereupon removed by two squeezing rollers. The thus removed liquid is caused to descend onto an inclined ledge which forms part of the guide and directs the liquid, as well as the impurities contained therein, into the compartment between the bottom wall of the vessel and the underside of the guide. Such compartment communicates with the remaining part of the internal chamber of the vessel by way of apertures provided in the guide and distributed and/or dimensioned in such a way as to at least reduce the rate of liquid circulation between the remainder of the internal chamber of the vessel and that part of the compartment wherein the impurities tend to accumulate by gravity.

Description

nited States Patent Waschk et al.

[ Feb. 8, 1972 [54] APPARATUS FOR WET TREATMENT OF PHOTOGRAPHIC FILMS OR THE LIKE [72] Inventors: Fritz Waschk; Jurgen Muller, both of Munich; Heinrich Krieger, Starnberg;

[21] Appl. No.: 31,287

6/1964 Cuthbert 1/1967 .....95/89 Nardone et al. ..95/89 Primary Examiner-Samuel S. Matthews Assistant Examiner-Fred L. Braun Attorney-Michael S. Striker [57] ABSTRACT A vessel which contains a supply of treating fluid for webs of photographic films or the like accommodates a guide having a concave upper surface along which a web advances lengthwise to be thereby immersed into the liquid and to continuously withdraw some liquid which is thereupon removed by two squeezing rollers. The thus removed liquid is caused to [30] F i li i p i i m descend onto an inclined ledge which forms part of the guide and directs the liquid, as well as the impurities contained Apt. 25, 1969 Germany ..G 69 16 867 therein, into the compartment betwean the bottom wa of the vessel and the underside of the guide. Such compartment C(Ill. communicates with the remaining part of the internal I u s I u a a v v e u a u u n l 0 v I u n u n u I a r I u u u [58] Field of Search ..95/89 R, 89 L, 94 R, 95, 96 guide and distributed and/or dimensioned in such a way as to at least reduce the rate of liquid circulation between the [56] References cued remainder of the internal chamber of the vessel and that part UNITED STATES PATENTS Ff the compartment wherein the impurities tend to accumuate avit 3,461,788 8/1969 Tiger at al ..95/89 X y gr y 3,263,590 8/1966 Wanielista et al ..95/89 X 8 Claims, 2 Drawing Figures 3a 2 ll l 8 I: I| ll ll i W l I 4c I :l 1' Q9 3 5.; n l L 34 *4 D H 4 A 3A a l "l l: I: P

APPARATUS FOR WET TREATMENT OF PHOTOGRAPIIIC FILMS OR THE LIKE BACKGROUND OF THE INVENTION N The present invention relates to apparatus for wet treatment of webs or strips of photographic film or the like.

In developing and many other types of film processing, webs, strips or sheets of photosensitive material must be caused to pass through one or more treating liquids. It is desirable to utilize such liquids with a maximum degree of efficiency. However, as the exhaustion of a developing solution for exposed photographic films progresses, the person in charge must regulate certain other factors which influence the quality of prints, such as the speed of travel through the treating liquid and/or the exposure time. This ensures that the quality of prints is not affected by the fact that the developing solution becomes less effective on prolonged use.

It is also known to prevent premature exhaustion of a developing solution for photosensitive material by segregating from the travelling webs or sheets all of the liquid which is entrained from the liquid bath and by preventing the return flow of such liquid into the bath. The liquid which adheres to the travelling web or sheet is most likely to be exhausted, i.e., the remainder of the liquid stays effective for a longer period of time. However, such removal of less effective liquid necessitates the provision of a level detector which prevents the liquid in the vessel from descending below a permissible minimum level by starting an automatic feeding device which admits fresh liquid when the detector produces a signal. Lossesin liquid which result from continuous withdrawal of some liquid by the transported webs or sheets are considerable so that such apparatus consume large quantities of fresh liquid or must be equipped with large quantities of fresh liquid or must be equipped with regenerators for the liquid which is withdrawn from the vessel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel and improved apparatus which renders it possible to utilize developing solutions and other liquids which are used for treatment of photographic films or the like with a degree of efficiency exceeding that of presently known apparatus.

Another object of the invention is to provide an apparatus for wet treatment of photographic films or the like which permits more efficient utilization of treating liquids than heretofore known apparatus and need not be provided with level detectors and similar expensive auxiliary equipment.

A further object of the invention is to provide a simple apparatus for wet treatment of photographic films or the like which prevents mixing of the exhausted part of treating liquid with the more satisfactory part of such liquid.

An additional object of the invention is to provide an apparatus which can be used with advantage in presently known developers and like machines for the treatment or processing of photosensitive materials in the form of webs, strips, sheets or the like.

The improved apparatus comprises a vessel or tank having a liquid-containing chamber, a preferably arcuate guide which is preferably removably accommodated in the chamber and whose upper side defines an elongated path extending at least in part below the liquid level whereby successive increments of a web or the like which travels along such path entrain some liquid as they move beyond the web discharging end of the path, the guide dividing the chamber of the vessel into a lower compartment which is located below the aforementioned path and an upper compartment which communicates with the lower compartment, preferably by way of suitably distributed apertures in the guide, liquid removing means adjacent to the web discharging end of the path above the liquid level and arranged to remove at least some of the liquid which is entrained by the web, and conveying means for directing the thus removed liquid into the lower compartment of the chamber. Thus, the exhausted or less effective part of the treating liquid and the impurities therein are caused to accumulate in the lower compartment whereby the heavier ingredients tend in the lower compartment whereby the heavier ingredients tend to accumulate in the lowermost part of the lower compartment and are unlikely to enter the upper compartment which contains the more effective part of the liquid. Also, the aforementioned level detector or detectors can be dispensed with because, if the liquid removing means is reasonably effective, nearly all of the liquid which was removed by a web is returned into the vessel so that the liquid level in the vessel does not decrease at all or decreases very slowly.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific .embodiments with reference to the accompanying drawing.

- BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic longitudinal vertical sectional view of an apparatus which embodies the invention;

FIG. 2 is a fragmentary transverse vertical sectional view as seen in the direction of arrows from the line Il-ll of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown an apparatus for wet treatment of webs W of photographic film or the like. The apparatus comprises a pair of cooperating advancing rolls 1, 2 at least one of which is driven and whichserve to transport the web lengthwise into the web-admitting end of an elongated arcuate path P defined mainly by the concave upper side 4A of an arcuate guide 4 removably installed in a vessel or tank 3 which isat least partially filled with a treating liquid. The

width of the vessel 3 preferably equals or exceeds only slightly the width of the web W and the longitudinally extending upright sidewalls of the vessel are provided with grooves 3a which permit rapid insertion and removal of the guide 4. The right-hand end wall 3A of the vessel 3 is inclined with reference to a vertical plane through about 30 so that any liquid which is caused to flow onto the wall 3A flows by gravity into the bottom part of a lower compartment LC defined by the parts 3, 4vbelow the path P. The illustrated apparatus further comprises an optional second or auxiliary guide 5 which flanks the path P from above and has projections vertically movably extending into the grooves 3a of the vessel 3.

The internal chamber of the vessel 3 further comprises an upper compartment UC through which the path P extends and which communicates with the lower compartment LC by way of apertures 4b, 5b (FIG. 2) provided in the

guides

4 and 5. Those surfaces of the

guides

4, 5 which flank the path P are preferably provided with

protuberances

4a, 5a in the form or ribs, rails or the like which ensure that the area of contact (and hence the friction) between the guides and the travelling web W is reduced to a minimum to thus guarantee thorough and long-lasting contact of all portions of the web with the treating liquid. The

protuberances

4a, 5a further promote the flow of fresh liquid into and in the path P.

The apparatus further comprises a pair of driven squeezing rollers 6, 7 which constitute a liquid removing device and are located above the liquid level adjacent to the web-discharging end of the path P. An adjustable deflector 8 is provided upstream of the rollers 6, 7 to direct the leading ends of webs into the nip between these rollers. The purpose of the rollers 6, 7 is to remove at least some and preferably all or nearly all of the liquid which is entrained by successive increments of the web W as such increments emerge from the liquid bath at the discharging end of the path P. The rollers 6, 7 also serve to transport the web W forwardly, e.g., into another vessel, through a drying station or to another destination. The liquid which adheres to the underside of the web W is immediately transferred onto the peripheral surface of the lower squeezing roller 7 and drips downwardly toward the adjacent part of the vessel 3. The liquid which adheres to the upper side of the web W is arrested by the peripheral surface of the upper roller 6 and is caused to form a wave whose ends descent by gravity toward the lower roller 7. Some liquid of such wave flows backwardly along the inclined upper side of the web W to reenter the vessel 3, and some such liquid is intercepted by the deflector 8 and is caused to flow off the web toward a conveying plate or ledge 4c which directs liquid into the lower compartment LC, namely, onto the inclined wall 3A of the vessel 3. Thus, the major part of that liquid which is withdrawn from the bath by successive increments of the web W is transferred onto the lower roller 7 which is disposed above the conveying ledge 4c. The latter is shown as forming an integral part of the guide 4. The amounts of liquid which flow along the upper side of the web W and back into the discharging end of the path P depend on the speed of the web, on the viscosity of liquid and on certain other factors.

The ledge 40 and the wall 3A define a relatively narrow passage of gap 34 through which the removed liquid must flow in order to enter the lower compartment LC of the chamber in the vessel 3. The inclination of the upper side of the ledge 4c is sufficient to insure satisfactory flow of liquid into the passage 34.

The operation:

The leading end of a fresh web W is introduced into the nip between the advancing rolls 1, 2 which transport the web into and beyond the receiving end of the path P. The tendency of the web W to roll and the fact that the web is somewhat inclined with reference to the central plane of the channel between the

guides

4 and 5 sets the treating liquid in the channel into motion, at least partly in the direction toward the discharging end of the path P. Therefore, liquid is caused to enter the channel between the

guides

4, 5, mainly from the uppermost part of the upper compartment UC above the guide 5. Such liquid can enter the channel by way of apertures 5b in the auxiliary guide 5. Consequently, a circulation of liquid takes place from the upper part of the compartment UC into the channel between the

guides

4, 5 whereby the web W is treated by a liquid which is less exhausted than that in the lower compartment LC.

The removal of withdrawn liquid starts as soon as the leading end of the web W reaches the nip between the rollers 6 and 7. Such liquid is caused to trickle or drip onto the downwardly inclined upper surface of the conveying ledge 4c and enters the lower compartment LC by way of the passage 34. The liquid which is withdrawn by successive increments of the web W at the discharging end of the path P contains impurities whose specific weight is higher than that of the uncontaminated liquid. Therefore, the contaminated liquid flows into and accumulates in the lowermost part of the compartment LC. Such liquid expels from the upper part of the compartment LC equal quantities of uncontaminated or less contaminated liquid which passes through the adjacent apertures 41: and enters the channel between the

guides

4 and 5. Thus, the utilization of treating liquid is very efficient because the exhausted (contaminated) liquid expels from the lower compartment LC the more satisfactory liquid into repeated contact with travelling webs. The distribution of apertures 41; in the guide 4 can be selected in such a way that the number and/or the cross-sectional area of such apertures is less in the lowermost (central) part of the guide 4 to thus reduce the likelihood of recirculation of contaminated liquid which accumulates in the lowermost part of the compartment LC. If desired, the apertures 4b can be provided only in the two upwardly extending portions of the guide 4 so that the lowermost pan of the compartment LC is practically sealed from the channel between the

guides

4 and 5.

FIG. 1 further shows that the lowermost central portion of the guide 4 constitutes a means for impeding circulation of liquid between the right-hand and left-hand sections of the lower compartment LC to thus further reduce the likelihood of entry of contaminated liquid into the channel between the

guides

4 and 5. On the other hand, the configuration of

guides

4, 5 and of apertures 5b promotes the circulation of satisfactory liquid in the upper compartment UC. However, the circulation-impeding portion of the guide 4 is sufficiently distant from the upper surface of the bottom part of the vessel 3 to permit the impurities to pass therebelow, i.e., to avoid clogging of the median part of the compartment LC. The transverse rib 3B of the vessel 3 also constitutes a circulation impeding part which interferes with free circulation of contaminated liquid in the lower compartment LC. If desired, the apparatus can be provided with discrete baffles or like devices which are inserted into the vessel 3 to prevent or impede the circulation of contaminated liquid in the lower part of the compartment LC It was found that the improved apparatus is capable of ensuring highly satisfactory utilization of treating liquids (e.g., of activators which are used for treatment of photosensitive materials) even though such apparatus need not be equipped with regenerators, level detectors and/or other expensive auxiliaries. The activity of the liquid bath is reduced more gradually than in presently known apparatus, and this is attributed, to a considerable extent, to such mounting of the guide 4 that it divides the internal chamber of the vessel 3 into two compartments the lower of which receives liquid which is removed from the webs and wherein the circulation of liquid is much less pronounced than in the upper compartment. Furthermore, the conveying ledge 4c cooperates with the wall 3A to insure that the returning liquid enters the lower compartment LC in the form of a stream which is practically free of turbulence so that the heavier impurities can accumulate and settle in the lower part of the compartment LC by gravity and remain in such lower part while the webs are caused to pass through the channel between the

guides

4 and 5. Furthermore, and as explained above, the returning liquids expels from the upper part of the lower compartment LC such liquid which is less contaminated and is therefore more suitable for treatment of photosensitive material.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Apparatus for wet treatment of webs of photographic film or the like, comprising a vessel having a liquid-containing chamber; a guide provided in said chamber and having an upper side defining an elongated path which extends at least partially below the liquid level and has web-admitting and web-discharging ends whereby successive increments of a web which is caused to advance along said path entrain some liquid as they move beyond said discharging end, said guide dividing said chamber into a lower compartment located below said path and an upper compartment which communicates with said lower compartment; means for impeding the circulation of liquid in said lower compartment; liquid removing means adjacent to the discharging end of said path above the liquid level and arranged to remove at least some of the liquid which is entrained by successive increments of a web; and conveying means for directing the thus removed liquid into said lower compartment by gravity flow.

2. Apparatus as defined in claim 1, wherein said conveying means is provided with an inclined surface along which the removed liquid flows by gravity into said lower compartment, said conveying means and said vessel defining a relatively narrow passage for entry of removed liquid into said lower compartment by gravity flow.

3. Apparatus as defined in claim 1, wherein said conveying means forms an integral part of said guide.

7. Apparatus as defined in claim 6, wherein the distribution and/or the dimensions of said apertures are such that the rate at which the liquid can circulate between the first part of said lower compartment and said upper compartment is less than the rate of circulation between the upper compartment and the second part of said lower compartment.

8. Apparatus as defined in claim 1, further comprising a second guide received in said vessel and flanking said path from above.

Claims

4. Apparatus as defined in claim 1, wherein said circulation impeding means forms part of said vessel.

5. Apparatus as defined in claim 1, wherein said circulation impeding means forms part of said guide.

6. Apparatus as defined in claim 1, wherein the liquid which is removed from successive increments of a web contains impurities which tend to accumulate in a first rather than a second part of said lower compartment and wherein said guide is provided with apertures permitting the flow of liquid between said upper compartment and at least the second part of said lower compartment.