Developing Device for a Horizontally, Transported Photographic Layer Carrier

The present invention relates to a developing apparatus for developing a photographic layer carrier, particularly a sheet film, in which the layer carrier is transported in the horizontal direction between the upper and lower processing chambers by means of two pairs of rotating rollers, of which one pair is arranged at the inlet of the device and another pair of rollers is mounted at the outlet side of the device. A processing liquid is pumped under pressure through a passage extended over about the whole width of each chamber towards the layer carrier movable in the processing space formed between the upper and lower chambers.

The film developing device of the type under discussion is disclosed, for example in German patent No. 1,293,586. Liquid vortexes occur in the fluid passages provided in the known film developing devices of the foregoing type; these vortexes which are generated by non-uniform streams of the processing liquid discharged from the slots, formed in the upper and lower chambers, unfavorably affect the developing process in the region of the layer carrier.

It is an object of the present invention to provide an improved film developing device.

It is another object of this invention to provide for a uniform stable distribution of the processing liquid in the region of the film being developed.

These and other objects of the invention are attained by a developing device for developing a photographic layer carrier, particularly sheet film, comprising an inlet pair of rotary transport rollers; an outlet pair of rotary transport rollers spaced from said inlet pair, said inlet pair of rollers and said outlet pair of rollers transporting a photographic layer carrier to be developed in the horizontal direction; means forming an upper liquid-admitting chamber and means forming a lower liquid-admitting chamber positioned opposite to each other and spaced from each other to define a processing space therebetween in which the layer carrier is transported, each of said chambers being supplied with a processing liquid under pressure, each means including a passage extended over the entire width of each means and a slot extended over about the entire width of the layer carrier, the processing liquid being admitted through said passage of each means and being discharged through the slot of each means into said processing space towards the layer carrier, each chambr including a comb-like partition means subdividing each chamber into two substantially parallel passage portions, said partition means extending over the length of each chamber and over the width of the layer carrier, the processing liquid being pumped into a first one of said two portions of each chamber, and said slot being formed in a second portion of each chamber.

The first portion of each chamber may be positioned at an inlet side of the device and the second portion of each chamber is positioned at an outlet side of the device.

The first portion of each chamber may be reduced in cross-section in the direction of elongation of said passage.

The second portion of each chamber may have a constant cross-section over the width of each chamber.

Each chamber-forming means may be formed of synthetic plastic material.

Each chamber-forming means may have a trough-shaped wall portion and a cover wall portion connected to each other to enclose said chamber therebetween.

The trough-shaped wall portion may have a reinforcement, said cover wall portion carrying said comb-like partition means, said reinforcement supporting said partition means.

The reinforcement may be formed by a longitudinal rib projecting from the trough-shaped wall portion of each means inwardly of the chamber.

The comb-like partition means may include a plurality of parallel teeth each being an angular element of rectangular cross-section.

Each of said teeth may have a shorter leg extended parallel to the direction of transportation of the layer carrier and having an edge facing towards the trough-shaped wall portion of each chamber-forming means and lying on said longitudinal rib.

The depth of said edge may be equal to the width of the longitudinal rib, said edge and said rib being flush with each other and both merging into said first passage portion.

The device may further include a first additional chamber formed at said inlet side between a lower roller of said inlet pair and said lower processing chamber.

The developing device may further include a first sealing plug positioned in said first additional chamber, said first additional chamber having an upper wall, said first sealing plug abutting against said upper wall and against the lower roller of said inlet pair, said first sealing plug extending over a maximal width of the layer carrier.

The device includes a liquid collecting bath, and a discharge passage for the processing liquid may be formed in said collecting bath between said first additional chamber and said lower chamber.

The device may further include a second additional chamber fromed between said lower chamber and a lower roller of said outlet pair at said outlet side and having an upper wall.

A second sealing plug may be positioned in said second additional chamber and extend over a maximal width of the layer carrier, said plug abutting against the lower roller of said outlet pair and the upper wall of said second additional chamber.

The first and second sealing plug may release further liquid returning passages for the processing liquid, formed respectively before and behind the first and second sealing plug and projecting along the lower rollers of the inlet pair and the outlet pair.

Each chamber-forming means may have a wall means directed towards the layer carrier being transported, said wall means being formed as baffles for the processing liquid discharged through the slot of each chamber forming means.

The developing device may further include means for connecting said lower chamber forming means to said upper chamber forming means in a predetermined position relative to each other. These connecting means may be pins or bolts.

Due to the subdivision of the liquid admitting chamber into two portions by means of the comb-shaped partition it is provided that vortexes, generated in one chamber portion upon pumping of the liquid thereinto are loosened by the teeth of the comb-shaped partition and the liquid is uniformly distributed through the length of the passage and of the slot in the second chamber portion. Thereby a stable, uniform discharge of the liquid from the discharge slot is provided and a uniform distribution of the processing liquid in the processing space is obtained. This effect is even more increased because the teeth of the partition means due to a specific construction are supported on the longitudinal rib provided in each chamber.

Due to the provision of the additional discharge passage the liquid flows into the collecting bath, and there is no disturbance to the processing liquid flowing over the layer carrier takes place in the developing process.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

FIG. 1 is a sectional view through a developing device according to the invention in a plane parallel to the direction of movement of a photographic film and, immediately behind feed or supply connections for a processing liquid in inoperative position;

FIG. 2 is a sectional view similar to that of FIG. 1 but of the device in an operative position; and

FIG. 3 is a perspective exploded view of the upper and lower processing chambrs shown in FIGS. 1 and 2, on the enlarged scale.

Referring now to the drawings more specifically reference numeral 3 designates a processing bath filled with a processing liquid 4. It is to be understood that only a part of the developing device for a photographic layer carrier, preferably a sheet film, is shown in the drawings for the sake of simplicity. Those structural components of the developing device, which are commonly known, are not depicted in the drawings. The non-illustrated layer carrier or film is transported along a flat displacement path 1 in the direction of arrows A, or from the left to the right in the plane of the drawing by means of two pairs of rotating transport rollers 1a, 1b and 2a, 2b. A wet processing device is a developing device in the present invention. The wet processing device can contain not only a developing liquid as a solution in bath 3 but also a fixing solution or a watering solution. Furthermore, the developing device of this invention can be utilized for a sheet film and a roll film as well. Rollers 1a, 1b are an inlet roller pair and rollers 2a, 2b are an outlet roller pair. Respective lower rollers 1b and 2b of both roller pairs are immersed in the supply-and-collecting bath 3 for developing liquid 4. The displacement plane 1 of the layer carrier lies in the plane of the mutual contact between rollers 1a, 1b or 2a, 2b.

A processing chamber is formed between two roller pairs 1a, 1b and 2a, 2b. Two processing chambers, namely an upper processing chamber 5 and a lower processing chamber 6 are arranged in the processing chamber. Both chambers 5 and 6 are mirror-inverted relative to each other. Each chamber 5, 6 has a passage extended parallel to the width of the layer carrier, each of those passages being subdivided into substantially parallel passage portions 5a, 5b and 6a, 6b, respectively. Liquid 4 is pumped from bath 3 under considerable pressure into first passage portions 5a and 6a through a non-shown feed pipe positioned before the sectional plane shown in the drawings. Thereby the liquid 4 from the position shown in FIG. 1 will take the position shown in FIG. 2 and the chambers 5, 6 as well as the processing space formed therebetween will be filled with liquid 4. Each first chamber or passage 5a, 6a is considerably reduced in cross-section starting from the inlet point for liquid 4 towards the end of the respective passage as shown by contours 5c, 6 c. Such tapered shapes in the passages are normal in order to avoid a pressure drop along the length of the passage.

A further improvement in the proposed arrangement of the liquid conveying passages resides in that each second passage or chamber has a discharge slot for the distribution of liquid 4 on the layer carrier being developed.

With reference to FIG. 3 it will be seen each passage 5,6 is composed of a trough or tray portion 5d, 6d facing the layer carrier and a cover 5e, 6e assembled with the respective trough portion. A longitudinal rib 5f, 6f extends towards the respective cover 5e, 6e from the trough portion at the boundary between two chambers 5a and 5b or 6a and 6b. Rib 5f, 6f supports the edges 5h, 6h of the rectangular cross-section of parallel teeth 5g, 6g of a comb. Each comb 5g, 6g projects from the respective cover 5e, 6e towards the trough portion 5d, 6d. The discharge slot 5i, 6i for discharging processing liquid 4 into the processing space between chambers 5 and 6 is provided in the respective second chamber portion 5b, 6b and extends through the middle longitudinal plane of the second chamber portion.

The operation of the passage arrangement in which each passage 5, 6 is subdivided into two chambers by means of combs 5g, 6g is as follows:

The proessing liquid 4 which is pumped at a suitable pressure into the first chamber, or, passage portion 5a, 6a forms in spite of the increasing reduction in cross-section of this chamber a vortex which, when the liquid flows directly from this chamber into the processing space, will cause non-uniform streams and thereby non-uniform liquid distribution. Now, however, the liquid, which is under pressure, will flow first between the teeth of combs 5g, 6g into the second chamber or passage portion 5b, 6b whereby the generated vortex will break up and the liquid will be stably and uniformly distributed in the second chamber over the length of this chamber and will also smoothly and unformly flow through the longitudinal slot 5i, 6i into the processing space at which a uniform distribution of the liquid will be ensured. Due to the arrangement of the two-part liquid supply passage 5a, 5b; 6a, 6b and owing to the provision of comb-like separating partition between two parts of each liquid supply chamber a stable and uniform liquid feed into the processing space over the width of the layer carrier and for the entire duration of the developing process will be obtained so that the quality of the developing process will be substantially improved.

The shape each liquid-processing passage 5, 6 is not limited to a specific embodiment. It is advantageous that the depth of each edge 5h, 6h of the each tooth of the comb is equal to the width of the longitudinal rib 5f, 6f and that the edge of each tooth and the rib are flush with each other and merge into the first chamber 5a, 5b. Furthermore, although it is not necessary it is possible to provide a structure in which the teeth of the combs would extend through the entire height of the passage if it is proper with another dimensions of the liquid supply passage. The teeth of the combs are spaced at equal intervals from each other for the reasons of manufacturing. However, instead of the reduced cross-section of the first passage portion 5a, 6a or in addition to such a shape of the first passage portion the teeth of the combs can lie closely to each other at the beginning of the channel and at the discharge region, or in the area of higher pressures and greater resistance to those pressures on the contrary at greater intervals from each other. Also the joint portions extended from the through portions and cover portions 5d, 5e and 6d, 6e can be formed by sealing rings instead of labyrinth-like projections and recesses shown in the drawings. The second passage portion or chamber 5b, 6b as shown in the drawings, is limited in the longitudinal direction on the one hand, by the teeth 5g, 6g and ribs 5f, 6f and, on the other hand, by projections 5k, 6k which are provided on the respective cover portion and extend towards the bottom of the respective trough portion. It is also possible to omit projections 5k, 6k at this side of the passage portion 5b, 6b and to form the inner wall of the cover portion so that it would extend to the respective wall of the trough portion or to the teeth forming the labyrinth.

Since the uniform liquid distribution in the processing space is obtained by the arrangement of the passages in comb-like partitions 5f, 5g it is possible to provide the return of the processing liquid into bath 3 by the shape or the arrangement of the discharge passages.

It is also advantageous that a further chamber 7 is provided between the lower passage or chamber 6 and the lower roller 1b of the inlet transport roller pair 1a, 1b. A sealing plug 8 abutting against the lower roller 1b and the upper covering portion 7b of the additional chamber 7 is positioned in this additional chamber 7; sealing plug 8 extends over the maximally possible width of the photographic layer carrier and does not extend over the entire width of the roller. A liquid returning passage 9 for returning the processing liquid 4 into bath 3 is formed between the lower passage or chamber 6 and the additional chamber 7. Passage 1 extends over the entire width of the photographic layer carrier. Since the sealing plug 8 extends over the maximal width of the photographic layer carrier the processing liquid 4 can drain in the region of the layer carrier, transported through the processing space, only through passage 9 whereas the return flow in the processing space along the lower roller 1b is prevented by the sealing plug 8. Only the liquid flowing laterally over the photographic layer carrier can drain along the edges of lower roller 1b along the side of the cylindrical plug 8 and downwardly into bath 3. Furthermore, the upper wall of lower passage 6, facing the photographic layer carrier, extends laterally beyond both passage portions 6a, 6b so as to form a cover portion 6m which encloses a further chamber 61 in which another sealing plug 10 is located, which abuts against the periphery of lower outer roller 2b and the edge of cover portion 6e. The length of sealing plug 10 also corresponds to the maximal width of the photographic layer carrier. It is also obtained thereby that liquid in the region of the layer carrier transported through the processing space can drain only through passage 9 and can pass over the layer carrier and flow then laterally of sealing plug 10 into the edges of roller 2b back into bath 3. Therefore the walls of chambers 5 and 6 facing the photographic layer carrier act as liquid conveying surfaces for the liquid flowing through slots 5i and 6i.

It is understandable that the manufacture of chambers or passages 5,6 having one portion or two portions or many portions is performed in accordance with specific shapes thereof; chamber 7 can be formed as a portion of chamber 6 with the release of passage 9. Furthermore, it is expedient that suitable conventional means be provided which should serve to exactly set the upper and lower chamber 5 and 6 relative to each other in the device after they have been disconnected from each other for cleaning. For this purpose pins or bolts 11 are provided which extend in respective bores formed in the walls forming the chambers 5, 6. The defined discharge passages, for example passage 9 and important sealing stoppers or plugs 8 and 10 as well as the correct position of chambers 5 and 6 relative to each other and the provision of the combs 5g, 6b within the chambers ensure the uniform distribution of the processing liquid in the processing space and therefore substantially improve the stability of the film development.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of developing devices differing from the types described above.

While the invention has been illustrated and described as embodied in a developing device for a photographic layer carrier it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

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 that, from the standpoint of prior art, farily constitute essential characteristics of the generic or specific aspects of this invention.