US3000287A - Apparatus for developing and/or fixing photographic printing material - Google Patents

Description

Sept. 19, 1961 P. H. HELDENS 3,000,287

APPARATUS FOR DEVELOPING AND/OR FIXING PHQTOGRAPHIC PRINTING MATERIAL Filed NOV. 28., 1955 1 2 Sheets-Sh eet 1 1 11 1111 1/1 1/1 1 11/11 1 11 1 1 fig IIIIIIII'I'III'I "IIIIIIIIII'II'IIIIIII'IIIIIIIII INVENTOR PETER HENRICUS HELDENS p 1961 P. H. HELDENS 3,000,287 APPARATUS, FOR DEVELOPING AND/OR FIXING PHOTOGRAPHIC PRINTING MATERIAL Filed Nov. 28, 1955 2 Sheets-Sheet 2 I, I H

W a I dig}, 7 f 6&2?- 7.

dig/d INVENTOR PETER HENRICUS HELDENS ATTO R N EYS United States Patent F 3,000,287 I APPARATUS FOR DEVELOPING AND/ORFIXING PHOTOGRAPHIC PRINTING MATERIAL Peter Henricus Heldens, Venlo, Netherlands, assignor to Chemische Fabriek L. van der Grinten N.V., Venlo,

Netherlands, a Dutch limited liability company Filed Nov. 28, 1955, Ser. No. 549,493

Claims priority, application Netherlands Nov. 30, 1954 7 Claims. (CI. 9589) 'The invention relates to an apparatus for developing and/ or fixing photographic printing material, particularly diazotype copies, in which the material is wetted on both sides with a thin layer of liquid, provided with two rotatable liquid-applying rollers, contacting each other along generating lines and having surfaces impervious to liquid, their length being at least 30 times their diameter and their diameter at least 15 mm. Apparatus of this kind is known. "Generally the wetting of sheet material ononeside leads to strong curling of thematerial, especially in the production {ofdiazotype prints by the semi-wet process. In this technique therefore simultaneous wetting 'of both sides is preferred. Thus'noncurling, flat copies are obtained. Naturally this is;also achieved when simultaneously developing double-sided copies. The practice of photo-printing employs rollers of a diameter which is practically always more than 15 mm. and the length of which'is" 30 and more times their diameter. I i Y With such dimensions of the rollers, in the usual apparatus the difficulty is encountered that dry spots may appear on the material'transported between the applying rollers. This is attributed to the fact that the rollers do nothave uniform mutual contact'along their. full length, that is to say that gaps are formedbetween them, owing to which the contact of the transported material witlnfi'foriexample, one of the rollersis. locally-lost, 'so that locally no liquid is applied. Gaps of a width of an order of'magnitude of :only'"0.lfmm.. are-"sufficient to bring thisabo'ut.

When sheet material is transported" between two' liquideapplyin'g rollers between which a gap exists, said material being narrower than the length of the gap and thinner than itswidthjdifiiculties sometimes'arise, such as slipping; especially when, asris usually the case,-the apparatus is not provided with special transportmeans. 'Naturallyx-the phenomena in questionare less troublesome if the rollers have a soft: covering of sufficient thickness, -butrsuch: soft coverings have other drawbacks; Such rollers run heavily, and thin sheets ofrelatively large dimensions. tend to crease while running through .the apparatus; -,In fact, in consequence of Ithe unequal local contact-pressure between the rollers, "the pressure between the rollers and the material transported between :thein is locally diife'r'ent; Moreover, owing .to the varying degrees of compression of thesoft cover,=differ.encw arise in the active radius of the roller, which lead to difierences in tangential speed. v r The present invention overcomes these difiiculties.

According to theinvention at least one ofthe rollers is'at least partially supported by theother roller and is lengthwise so flexible that, if-lying in a horizontal posi tio rr-andsupported'at the ends" only, it sags by-its own weightsubstantiallywalong a continuous or broken curve, the sagof its lowest generatingrzline being at; least 0.1%

ice

of the length of the roller. A sagging of 0.8 is a high value in relation to the average paper thickness, which amounts to approximately 0.1 mm. 1

In the apparatus according to the invention one of the liquid-applying rollers thus has a flexibility which permits this roller to adapt itself completely or at least con siderably to the other roller or rollers with which it om operates. Owing to this the appearance of dry spots during the wetting of sheet material on both sides is avoided. Gaps become smaller or are fully eliminated so that the transport of sheet material, especially narrow, thin sheet material, is considerably improved. The contact-pressure between the liquid-applying rollers becomes more uniform, so that, even when the flexible roller is made of soft material, the contact between the "rollers and the material transported between them is practically the same in the circumferential direction along the full length of the liquid-applying zone, and no differences in tangential speed occur. The invention will be more fully described with refer,- ence to the drawings.

FIGS. 1-3 are diagrammatic cross-sections, perpendicularly to the axes of the co-operating applying rollers of apparatus according to the invention in different enibodiments. I

FIG. 4 illustrates diagrammatically the distribution of forces in apparatus accord'ng to FIG. 2.

FIGS. 5-10 show various embodiments of flexible liquid-applying rollers for apparatus according to the in;- vention, in diagrammatic cross-sections.

, In'the FIGURESpl, 2, and 3, 1 and 2 are the liquid applying rollers which deliver in the applying zone 27 a thin layer of liquid 35, eg a diazot-ype developer, on to both sides of the material to be wet-ted 40, erg. diazo type paper of weight g./m. The rollers in the'ap paratus according to the FIGURES 1, 2, and 3 rotate in the directions indicated by arrows.

In FIG. 1, liquid-applying roller 1 is rotatably mounted in trough 33, which is partly filled with liquid 35. The trunnions of roller 1 are supported in bearings forming part of the frame 30. Liquid-applying roller 2 is a flexible tube filled with liquid, eg a rubber hose, provided at its upper ends with trunnions 7. It rests on roller land is held in position by trunnions 7 located in slots 32 in the frame 30. Both rollers have a length of cm. Roller '1 has a diameter of 3 0 mm., roller 2 of 27 mm. Roller 1 is an ordinary roller, e.g. a solid, metal roller, which, in spite of its rigidity but in consequence of its own weight and the weight of roller 2, sags somewhat, for example, by about 0.2 mm. in the middle. Because. the tubular roller 2 can sag at least 0.8 mm. per metre rollerlength, this roller can wholly follow the sagging of roller 1. The surface of roller 1 may be smooth or profiled. Roller 2 has a surface provided with capillaries, which receive a quantity of liquid from trough 33 via roller 1 when the apparatus is in operation without any materials being transported between the two rollers. This quantity of liquid is delivered during the transport of sheet material. Apparatus according to FIG. 1 is suitable for the wetting of sheets on both sides, the-top roller being permitted to fill its capillaries at intervals between the wetting of the sheets.

In the apparatus according to FIG. 2 two troughs, 33 and 34 are located at a short distance from each other. Bothare .partly filled, withliquid. 35,, Liquid-applying forces acting on the rollers 1 and different for the rollers 1 and 3 roller 1 is rotatably mounted in trough 33 and liquidtransmitting roller 3 is rotatably mounted in trough 34. Both rollers are provided with trunnions, 6 and 8 respectively, which are supported in stationary bearings. Liquid-applying roller 2 rests on the rollers 1 and 3. It may be supported by means of trunnions, or may be freely supported. The sheet material 40 is transported between the troughs 33 and 34 and the rollers 1 and 2. A thin layer ofliquid is applied on both sides in zone 27. In this apparatus the rollers 1 and 2 are continuously supplied with liquid, so that the sheet material 40 may be along web. r t

In the apparatus according to FIG. 3 the troughs 33 and 134 are situated at a greater distance from each other than in the apparatus according to FIG. 2. In both troughs liquid-transmitting rollers, 4 and 3 respectively are rotatably mounted. They are provided with trunnions, 9 and 8 respectively, which are supported in stationary bearings. The liquid-applying rollers 1 and 2 rest on the liquid-transmittingv rollers 3 and 4, and at the. same time rest against each other. One of the liquidapplying' rollers maybe flexible and the other may be an ordinary rigid roller. Alternatively both rollers 1 and 2 may be flexible rollers, but in that case at least one of them mustbe supported in bearings at its ends and must be rigid enough to. hold itself and at the same time the other liquid-applying roller in their position of cooperation with the liquid-transmitting rollers 3 and 4. Thus e.g. the trunnions 6 of roller 1 may be supported. in stationary bearings. Roller 2 may be freely supported; it may, however, also be provided with trunnion's 7 which are supported in bearings. Liquid-applying rollers 1 and 2 are continuously supplied with liquid by liquid-transmitting rollers 4 and 3. The surfaces of the liquid-applying rollers 1 and 2 of apparatus according to FIGS. 2 and 3' may be smooth or profiled (i.e. grooved or the like). Also the surfaces of the liquid-transmitting rollers 3 and 4 may be smooth or profiled. For satisfactory functioning of the apparatus it is, however, necessary that a sufiicient quantity of liquid is let through in the contact zones between liquidtransmitting and liquid-applying rollers. It is desirable to provide ample opportunity for passage of the liquid in the contact zones between liquid-transmitting rollers and liquid-applying rollers, but to limit the quantity of liquid let through. This may be done by means of a doctor device for doctoring off, the excess of liquid from the surface of the transmitting rollers. Such a doctor device is, for example, the" doctor roller indicated in dotted lines in FIG. 3'. By means of such doctor devices an almostunvarying liquid application may be obtained at varying transport velocities of the sheet material.

FIG. 4' diagrammatically illustrates how, in an apparatus according to FIG. 2, roller 2 exerts pressure on both the lower rollers 1 and 3. The vectors 22, 23, and and 24 illustrate. respectively what forces act on the rollers 2, 1, and 3' owing to their own weights. The weight of roller 2 may be resolved into the vectors 22a and 2212, which represent the forces with which the lower rollers are loaded by the weight of roller 2. The total 3 are ultimately determined inmagnitude and direction by the vectors 25 and 26'. Under the influence of these forces the lower rollers will sag somewhat in the direction of the vectors 25 and 26. As the rollers 1 and 3 are supported at their ends, the sagging will be greatest in the middle of the rollers and will decrease towards the ends. Generally this sagging will be different for the various rollers, but at least i on the onehand and the roller 2 on the other hand. Thus, gaps. appear in the liquid-applying zone 27 and in the contact zone 28.

In an apparatus, according to FIG. 2, liquid-applying roller-f2 may be so compressible that its rollerprofile is not perfectlycircu-lar when it rests on the rollers 1 "and 3'." Preterabl y, however,- the flexible roller in: the

apparatus according to the invention is elastically dewall of which consists of formable, though with sufficient rigidity substantially to preserve the circular roller profile.

FIG. 5 is an illustration of a longitudinal section of a roller consisting of a tube 11 with circular section. The tube may be made, for example, of relatively soft rubber (e.g. 5070 Shore) and may have a wall thickness of a few millimetres. Such a tube is very flexible lengthwise, whereas its cross-section is rather rigid. In an apparatus according to FIG. 2 roller 2 works very well when it is made according to FIG. 5. Alternatively, tubes made of softer materials or rubber tubes with a very thin wall may be used- Thus, for example, it is possible to construct flexible, elastically deformable tubular rollers, with suflicient rigidity substantially to preserve the circular roller profile, by means of a cover of flexible material, e.g. waterproof tissue: with an inner coating of a continuous row of rings, the outer diameter of which is equal to the inner diameter of the cover. Whenusing a rubber tube with a wall thickness of 1 mm. or less, it is possible to obtain suflicient rigidity to preserve the circular roller profile by closing the tube at its ends and charging it with air under pressure.

FIG. 6 illustrates a diagrammatical longitudinal section of a tubular roller the elastically deformable tube a cover 11 and a spiral spring the tube at the ends. Instead spring 12, separate rings may also be used for 12. Small plates 13 close of spiral internally supporting the cover 11.

In apparatus for wetting sheet material on both sides the liquid-applying rollers also often have to provide for the transport of the material against a certain resistance. Often broad and long sheet-shaped material has to be transported through the apparatus, for example, as a somewhat tensioned web. In order to obtain a sufiicient pull for this, the liquid-applying rollers either have to be pressed against each other with the necessary force, or have to be heavy enough when they rest on or against each other by their own weight. In the apparatus according to the invention a suflicient pull between the liquid-applying rollers may easily be obtained by providing a tubular flexible liquid-applying roller with a filling. of a fluid substance or of solid bodies, which are movable in relation to one another at least in a direction transverse to the tube. The fluid substance. may be a liquid, e.g. water, aqueous solutions, mercury and the like or a powder or granular material, such as sand, gunshot, and the like.

FIG. 7 illustrates in diagrammatic longitudinal section a tubular roller with elastically deformable cover 1 1', which is filled with pieces of solid material 15a and 15b which are movable in relation to each other. The

material is, for example, iron. Instead of using fairly large pieces of such material, such as 15a and 15b, the tube may be filled with smaller pieces, such as the discs 16, as illustrated in FIG. 7A. I

The pieces 15:: and 15b are ball-and-socket jointed so thatthey can hinge in relation to each other, but cannot relatively move in a direction transverse to the axis of the tube. V

The rollers according to FIGS. 5, 6, and 7 not being provided with trunnions, they are only suited for use in apparatus in which two other rollers, such as the apparatus according to FIG. 2 or 3. In apparatus according to FIG. 1 it is necessary to give the flexible roller some bearing,- in order supported in bearings consist of a: tube provided with a continuous: rigid core, with suflicient fredom of transverse movement. in relationto the tube wall and the they are supported by at least tube filling respectively for preserving the desired degree of ,deformability of the tube wall. These flexible rollers are easier to handle than those without a core.. They can easily be taken out of the apparatus and stored with the ends of the core resting on supports. 1 f

In the flexible roller according to FlG. 8, of which a transverse cross section is seen in FIG. 8A, the elastically deformable tube 11 is closed at its ends by plates 14. Core 10. with trunnions 7- has been passed through these plates and is fastened to them. The space between core 10.and ithe .innenwall .of tube. 11 is partly filled with rings 17.. -Theserings sarepr'ovided with holes" of a greaterdiameter than thatof core 10. The outer diameter' of "therings issmaller than the inner diameter of the tube 11'. Thus the, roller according to FIG..8i has good transverse deformability along its full length.

FIG. 9 illustrates a roller of a similar construction to that according to FIG. 8. The filling consists of granular bodies 18 and 19. Granules 18 have a smaller size than granules 19 with equal specific gravity, or have higher specific gravity with equal size. This flexible roller will thus apply a higher pressure against the other roller or rollers in the middle than at its ends.

In the flexible roller according to FIG. 10 the space between core 10 and the inner wall of tube 11 is partly filled with liquid 2.0. When tube 11 is very flexible, its circular roller profile may be preserved by means of small discs 21, which are secured to core 10 at regular intervals. These small discs may be provided with passages so that the compartments into which they divide the tube are interconnected.

In the flexible rollers according to the FIGS. 9 and 10 the spaces between core 10 and the inner wall of tube 11 may be completely filled with the fluid substances 18, 19, and 20 respectively.

In order to obtain an even distribution of a thin layer of liquid on both sides of the sheet material, the surfaces of the liquid-applying rollers preferably have been or are provided with capillary recesses. Suitable recesses are, for example, pits, while grooves extending transversely to the axes of the rollers along their circumference are also very suitable. Grooves of a depth-of, for example, 1 mm. and a width of 0.15 mm. at distances of 0.45 mm. are very suitable.

When in the apparatus according to the invention the flexibility of the flexible rollers, and accordingly the uniformity of the applying pressure in the liquid-applying zone between the liquid-applying rollers is increased, it is possible to decrease the applying pressure per unit of length of the rollers and yet retain sufficient pull for the transport of broad and long sheet material as well as sufficient uniformity of liquid-application. Low applying pressure is advantageous when working with vulnerable materials, e.g. materials the surface of which is coated with a soft film layer.

The invention is not limited to the illustrated embodiments; it may be varied within the scope of the claims.

'I claim:

1. An apparatus for applying liquid evenly to both sides of a moving photographic sheet material, comprising a plurality of horizontal rotatable rollers each having a diameter of at least 15 mm. and a length of many times its diameter, said rollers bearing one against another along generating lines of their outer surfaces so that they rotate together, the outer surfaces of said rollers being substantially impervious to liquid, and means for distributing liquid over said surfaces, at least one of said rollers having at least part of its weight supported by another of said rollers along its line of contact with the latter and being flexible and saggable bodily along said line under its own weight but comprising means maintaining its circumferential profile traversing said line substantially uniformly convex at all locations along said line as said rollers are rotated, those two of said rollers forming between contiguous portions of their respective outer surfaces a passage for applying liquid to both sides of said material, said one roller when supported horizontally at its ends only having a sag along its lowest generating line. amounting to at least 0.1% of its length. f I .2. apparatus for applying liquid evenly to both sides. of a moving photographic sheet material, comprisingat least three horizontal rotatable rollers bearing'one against another along generating lines of their outer-surfaces so that they rotate together, the outer surfaces of said rollers being substantiallyimpervious to liquid, and means for distributing liquid over said surfaces, at least qneofsaid rollers being mounted for free verticalmovement andhaving parts ras weightsupported respectively by two other ofsaidrollersalong-its lines of contact with the latter, said surfacesof said two rollers respectively carrying films of liquid to said lines, the outer surface of said one roller receiving a thin film of liquid from said surface of one of said two rollers along one of said lines, contiguous outer surface portions respectively of said one roller and of the other of said two rollers forming therebetween along the other of said lines a passage for applying liquid to both sides of said sheet material, said one roller being flexible and saggable bodily along each of said lines under its own weight but comprising means maintaining its circumferential profile traversing each of said lines substantially uniformly convex at all locations along said lines as said rollers are rotated, said one roller when supported horizontally at its ends only having a sag along its lowest generating line amounting to at least 0.1% of its length.

3. An apparatus for applying liquid evenly to both sides of a moving photographic sheet material, comprising at least three horizontal rotatable rollers each having a diameter of at least 15 mm. and a length of many times its diameter, said rollers bearing one against another along generating lines of their outer surfaces so that they rotate together, the outer surfaces of said rollers being substantially impervious to liquid, and means for distributing liquid over said surfaces, at least one of said rollers having parts of its weight supported respectively by two others of said rollers along its lines of contact with the latter, said surfaces of said two rollers respectively carrying films of liquid to said lines, the outer surface of one of said rollers receiving a thin film of liquid for said surface of one of said two rollers along one of said lines, contiguous outer surface portions respectively of said one roller and of the other of said two rollers forming therebetween along the other of said lines a passage for applying liquid to both sides of said sheet material, said one roller being flexible and saggable bodily along each of said lines under its own weight but comprising means maintaining its circumferential profile traversing each of said lines substantially uniformly convex at all locations along said lines as said rollers are rotated, said one roller when supported horizontally at its ends only having a sag along its lowest generating line amounting to at least 0.1% of its length. i

4. An apparatus as described in claim 3, said one roller comprising a flexible cylindrical tube containing a multiplicity of filling elements displaceable relative to one another in directions transverse to the length of said tube but relatively non-displaceable in the direction lengthwise thereof.

5. An apparatus as described in claim 3, said one roller comprising a flexible cylindrical tube containing a multiplicity of rigid filling elements each of which has a cylindrical outer surface supporting a longitudinal section of the wall of said tube, said elements being displaceable relative to one another in directions transverse to the length of the tube but relatively non-displaceable in the direction lengthwise thereof.

6. An apparatus as described in claim 3, said one roller comprising a fle 'ble cylindrical tube, a rigid core extending axially through said tube, and a multiplicity of contiguous rigid filling elements lying between the wall of said tube and said core, said elements resting freely wear-.28

i 1- An apparatus as described in claim 6, said filling elemerits being in the 'fo rrn of cylindrical rings surrounding said core andhaving a substantially uniform outside divarneter; smaller than the inside diameter of said 'wall. References Cited the file of this patent f UNITED-STATES VPATENTS 42, 415 sweeter; Apr. '19, 1864 7 "580,509. V ,Rochester Apr. 13, 1 897 654,194 Twohy July 24, 1900 Crompton Apr. 1, I913 5 Lawrence July-3; 1917 Top'hanl Feb. 12, 1929 Tailtz v Apr. 25 19.33 lGundlach Apr, 19/ ,'1938 Nagels iet a1. -Q-AilgL 5, 111952 Larnrhertse ;;Jan. 27, 1953 FOREIGN PATENTS V K "France Oct. 20, 1930 Germany Jam 21; 193] France .4; Aug; 21, 1939 Great Britain Feb.. 26, 1 941 France Dec. 11, 1943 France Mar. 31,1947 Great Britain Oct. 7, 1953 ."for" read from v Attesting'Offioer Commissioner of Patenlts UNITED STATES PATENT OFFICE f 1 CERTIFICATE OF CORRECTION Patent No. 3,000,287 September 19 1961 Peter Henricus Heldens It is hereby certified that error appears in the above numbered patentrequiring correction and that the said. Letters Patent should read as v corrected below. A

Column 2, line 43, strike out "upper"; column 4, line 74," for -."fredqm" read freedom column 6, line44, for

Signed and'seal'ed this 20th day of February 1962.

(SEAL) Attest:

' ERNEST w. SWIDER. DAVID L. LADD A UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,000,287 I September 193,; 1961 Peter Henricus Heldens It is herehy certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 43, strike out '.upper"; column 4 line 74,; for fredonf read freedom column 6 line 44, for "for read from Signed and sealed this 20th day of February 1962.

(SEAL) Attest:

' Attesting Officer ERNEST W. SWIDER DAVID L. LADD Commissioner of Paton

Images