US2234796A - Apparatus for making light sensitive prints - Google Patents

Description

March 11, 1941. H. J. BRUNK APPARATUS FOR MAKING LIGHT SENSITIVE PRINTS Original Filed March 14, 1935 3 Sheets-Sheet l Bnucntor W W Q (ZttorneuS March 11, 19411 BRUNK 2,234,796

APPARATUS FOR MAKING LIGHT SENSITIVE PRINTS Original Filed March 14, 1955 3 Sheets-Sheet 2 Imvontor M11 y G1torncg5 March 11, 1941.

H. J. BRUNK APPARATUS FOR MAKING LIGHT SENSITIVE PRINTS Original Filed March 14, 1935 pra c== ==F 3 Sheets-Sheet 5 Patented Mar. 11, 1941 PATENT OFFICE APPARATUS FOR MAKING LIGHT SENSITIVE PRINTS Harold J. Brunk, Chicago, Ill., assignor to The C. F. Peale Company, a corporation of Delaware Original application March. 14, 1935, Serial No. 11,142. Divided and this application January 21, 1939, Serial No. 252,203

10 Claims. (Cl. 95-75) My invention relates to improvements in apparatus for making photographic prints, 1. e. prints made by exposing to light a sheet of paper or other suitable membrane having light sensitive chemicals applied thereto. Blue prints are included among those falling within the scope of the invention. In developing such prints water is used resulting in so-called bleeding, 1. e. discoloration of the white areas by the blue coloring material. t

The main object of the present invention is to provide new and simple means for overcoming the diiiiculties due to rurming and bleeding heretofore inherent in the use of liquid in developing photo-copies or prints.

A contributory object is to provide means for applying liquid to the side of the. sheet opposite the one having the light sensitive coating thereon whereby the required reaction is made possible by the fact that the said liquid works its way through the sheet from the back to the front.

Another object is to provide means for applying water to the uncoated surface of a sheet of blue print paper to cause absorption of said water by said sheet and start the oxidation of the chemicals comprising the coating.

Another object is to provide mechanism i'or applying water first to the back of the blue print after it has been exposed and thereafter applying water to the front thereof with enough of an interval between the two to permit initial oxidation suilicient to prevent bleeding.

A further object is to provide mechanism whereby the length of the span of paper traveling between the first and second application of water may be varied to insure the desired time for initial oxidation.

An additional object is to provide means for applying moisture to the exposed or coated surface of the paper by means of a dampened, absorbent material brought in contact with said surface but with no slippage.

In the accompanying drawings I have illustrated several embodiments of the invention in the form of attachments to well known types of so-called continuous blue printing machines. The invention may be embodied in other forms, however, and used in fields other than photography.

Fig. l is a side elevation 01' part of a blue printing machine, with the form oi attachment;

Fig. 2 is a side elevation of a modified form of the invention;

Fig. 3 is a side elevation of a further modification;

Fig. 4 is a side elevation of an additional modification; and

Fig. 5 is a sideelevation of a further modification.

The operation of the machine as a whole will be understood from Fig. 1. The sensitized paper is fed through the machine from a roller, passing rearwardly andupwardly past a source of light,

with the necessary tracings or negatives held against said sensitized surface whereby the printing is accomplished. The span of paper thereafter continues its travel toward the rear of the machine, passing up and down over various rollers. The first application of water is made by passing said span of paper under one of said rollers which is being continuously sprayed with water, this roller making contact with the back or unsensitized side of the paper, whereby the moisture thus applied soaks through the paper reaching the chemical on the coated side and causing an initial oxidation. The paper then continues its travel, passing through the usual water wash which washes ed the superfluous chemicals but without causing bleeding or running, after which the paper, as it continues its travel, is treated to an application of potashor other oxidizing agent, and to a final water wash, following which it passes through the drier and is then ready to be out up into prints oi the desired size.

Referring now to Fig. i more in detail, the particular machine shown therein comprises a suitable frame iii, having a supply of blue print paper in the form of a roll mounted on a rod it near the front of the machine. The paper is drawn from the roll in the form of a span i2 which passes rearwardly over a horizontal portion or table and thence upwardly past a curved sheet oi glass l3, past a row of arc lamps H, or other suitable source of light. Said paper then passes over rollers i5, i6 and down under tension roller ll, the shaft i8 of the latter being mounted in suitable, vertically adjustable bearings, not shown, which, however, are supported this figure of the drawings the reference l2, in-

dicating the span of paper, is applied to the sensitized side thereof, from which it will be seen that the arrangement of the rollers 2i, 22, 23 and 24 is for the further purpose of turning the paper upside down with reference to its position as it enters the machine initially and in general as it travels rearwardly.

The application of moisture to the back of the paper at this point in its travel is the important feature of the invention as the water is permitted to soak through the paper for a long enough periodfor oxidation to take place before the paper enters the conventional water wash, which in this case is located at the top of the unit, as hereinafter described.

Heretofore, water has not been applied to the back of paper as it passes through a blue, print machine except for preventing curling of the paper stock after the print has passed the 'usual water wash where the water is applied to the front or coated surface of the print. My im proved method differs from the prior practice in applying moisture to the back of the print in advance of the application of water to the coatedside of said print and in applying it in such a way that'it may soak through'the paper and reach the chemical from the rear.

With the particular arrangement described herein, the water which runs off from the edges of the paper is caught by a suitable V-shaped pan 26, surrounded by another tank 21, provided with a suitable outlet. In order to adjust the operation of the machine for the different speeds at which the paper may travel and to afford the necessary time for the moisture to soak through the paper before it reaches the usual water wash at the top of the unit, the supporting frame 28 for the three rollers 22, 23 and 24 may be adjusted vertically on suitable supports 29.

The water wash at the top of the unit is indicated generally by 30 and comprises rolls 3|, 32 and 33, around which the paper passes and at which point it is washed by water delivered in a spray from pipe 34 against the roller 32. An additional back wash 35 may be applied to the sheet as it descends over the roller 35, to prevent curling at the edges, this being common practice. The paper then passes under roller 37, on shaft 38 near the bottom of the machine, and thence rearwardly to the potash station, to a final water wash, and to the drier which may be any suitable or well known construction and is not described herein.

Referring again to the application of moisture to the rear of the print before it reaches the conventional Water wash, I have found that if warm water is used the oxidation process is greatly accelerated. Thus the pipe 25' may be connected to a suitable source of warm water.

I have also discovered that the oxidation process is hastened by applying to the front or sensitized side 'of the paper heated water vapor in small amounts. This vapor is applied in the allowed to oxidize.

plained, removes the partially reduced chemical vicinity of the roller or whatever device is employed for applying moisture to the back of the paper, the vapor preferably being applied simultaneously with the application of moisture to the back. This eliminates the necessity for a. lengthy soaking period between the initial application of .moisture and the conventional water wash applied to the front of the paper. 7

By applying water to the rear of the paper prior to washing the front, as with the apparatus disclosed herein, oxidation appears to be started with the chemicals that are deeply imbedded in the fibers of the paper prior to removing any chemical from the surface of the paper. This brings about a better blue print with deeper color from the same light exposure, This is probably due to the fact that if running water is first applied to the coated side of the sheet, the washing action or force of the water removes not only the outer layer of completely reduced insoluble chemical but also a certain portion of the incompletely reduced chemical buried in the fibers of the paper stock. This partially reduced chemical is capable of producing some of the insoluble blue substance which is Turnbulls blue, if it is The running water, as exbefore it has time to oxidize, whereas by applying the water to the back of the sheet, the chemical is moistened enough to start oxidation but with no tendency to remove it or mechanical action to remove it. This initial step as thus described may be termed a soaking process or step.

In hastening the oxidation process by the use of moisture laden air, it is not necessary'to supply the vapor in the form of steam. The vapor maybe supplied from any suitable source, either that arising from the warm water issuing from the pipe 25 or through a spray pipe 39, supplied for that purpose. Withthis double application of moisture to the front andrear of the paper, the moisture from the rear does not have to penetrate the entire thickness of the paper in order to oxidize the outer layer of the chemical. It is evident that either method may be used singly and that the combination of the two assures good results on high speed continuous blue printing machines.

In Fig. 2 the printing portion of the machine may be assumed to be the same as that previously described. The span of paper l2, after leaving the tension roller I! (the same as in Fig. 1) passes upwardly and over a water tank or trough 40, during which passage moisture is applied to the hack thereof, the coated surface being at the top. The paper passes over spaced rollers 4|, 4i and a middle roller 42 which latter dips into said trough 4B. As shown in dotted lines, one of the rollers 4| is mounted on adjustable arms 43 to elevate the span of paper above the roll 42. The trough is kept full of water from the reservoir 44. The roll 42 may be rotated in either direction, 1, e. with or against the direction of travel of the paper, depending on whether more or less moisture is desired at the under surface of the same. From this initial moistening equipment the span of paper may pass directly to the usual water wash, or, in the case of paper traveling at a high rate of speed, a second application of water to the rear thereof may be desirable. In such cases a second trough 45 is provided with a roller 46 dipping therein and auxiliary rollers 41, 48,

somewhat similar to those previously described. I

the machine stops.

Said water wash, indicated generally by reference 50, may be similar to that previously de-.

scribed ix: connection with Fig. 1. k

In Fig. 3 another modification is shown in which the span of paper II, after leaving the printer, passes a moistening roll 5|, which, with its adjuncts, is the same as what is shown in Fig. 1, whereby moisture is applied to the ,rear surface of the paper. From this location the paper passes over idle rollers 52 and binder rollers ll, 53, traveling in a horizontal span, coated side down, through a water bath in the tank N. The water is maintained at a constant level by overflow pipe 55, and the paper, as it becomes saturated and expands, is prevented from wrinkling by passing under curved or bowed bars 58, in a manner well, understood in the art. The water in this tank is not violently agitated but is comparatively still. The excess chemical which falls from the paper descends in the tank and is not carried alongthe surface in a way that would cause bleeding. Also, the initial application of water to the rear of the paper further insures against bleeding. From this tank the paper passes to the usual water wash, indicated generally by reference 51, which will be understood from the previous description of similar devices for washing the front of the print.

In Fig. 4 I have illustrated a modification or a different type, which might be said toinvolve a method of blotting the sensitized surface with moist, absorbent material after exposure, to withdraw the chemicals which it is desired to remove from the coated surface and to supply the necessary liquid. If an absorbent pad or ,blotter is pressed firmly againstthe surface of an subsequently subjected to the regular treatment with running water or a water bath.

In this apparatus the band of blue print paper II, after issuing from the printing section as heretofore, passes under a tension roller i1, thence upwardly over an idle roller 58 and down under rollers 59 and 60, upwardly and over roller 6| near the, top of the frame of the attachment and thence downwardly around larger roller 52 which is mounted on a suitable shaft 83.

The material for accomplishing the blotting or absorbing action is, in this case, a moist endless belt 64 of suitable material such as felt, which belt passes around rollers 65, 66, mounted near the main roller 62, said belt passing downwardly around rollers 51 and 68, which latter are mounted in a container or tank 69. The roller 61 is mounted on a pivoted arm 10 provided with a spring H which maintains suitable tension on the endless belt. The latter, it will be seen, is caused to bear against the coated side of the sheet of blue print paper I! where it passes "around the roll 82 and is held in firm contact therewith, without slippage, for more than half of the circumference of the roller 62. The length of the path of travel of the moist absorbent belt while it is in contact with the blue print, may be varied by adjusting the arm 12 on which the roller l is mounted, said arm being mounted to swing about the axis of the shaft 63. The span of paper has its coated side i2 uppermost as it leaves the printer and passes under the tension roller i1, one of the purposes of the additionalrollers between said tension roller and the main roller 62 being to turn the paper upside down during its travel so that its coated surface may be brought in contact with the absorbent belt 10 as both spans pass around said main roller.

It is necessary to wash from the absorbent halt the chemicals which adhere thereto while it is in contact with the exposed surface of the blue print paper, and for this purpose said belt is 15 passed through a water bath in the tank 69. The descending span is washed with water by means of a spray issuing from the pipe 13, the water being applied to the side of the belt which was in contact'with the blue print. This tends to wash the chemicals from the belt, which washing is further accomplished as the latter passes through the water bath in the tank, the level of the water being maintained by a suitable overflow pipe 14. If desired, a. revolving brush or brushes such as 15 may also be employed to aid in removing any surplus chemical from the belt. If the chemical were not removed it would, of course, be brought into contact with the surface of the print during the continued travel of the an endless belt around the main roller and would stain the blue print, due to the chemical reaction which would take place.

After the blue print paper leaves the main roller 62, it passes through a conventional water 35 wash, indicated at 16, but without any bleeding or running of the color and is thereafter fixed and dried in any suitable manner. C

In Fig. 5 a modification of the means for pressing the absorbent material against the span 40 of blue print paper, is illustrated. In the attachment just described the paper passes around a roller with its coated and exposed side outwardly, an endless belt of absorbent material being pressed against said coated side, and

the modified form of the device, the moist, absorbentmaterial forms an outer layer on a roller and the coated side of the paper passes over the roller facing inwardly instead of outwardly, and 50 hence is in contact with the absorbent surface of the roller. Thus in both cases, the exposed surface is brought into direct contact with the blotting material, and travels therewith without slipping relatively thereto. In the drawing (Fig. 5) 11 indicates the roller having a felt or other absorbent covering 18 and mounted to dip in a suitable tank 79, the water level in which is controled by an overflow pipe, as previously described. A spray of water from a pipe is directed upwardly against the lower part of the roller to wash the chemical therefrom in addition to the washing that the roller receives in turning with its lower part submerged in the water bath.

The operation described in connection with the apparatus of Figs. 4 and 5 might be called a mechanical method of applying moisture to the surface of a blue print and removing the loose, exposed chemical as well as the underexposed :0

chemical therefrom and without the possibility paper or other material, as used in various other fields. {Various changes may be made, therefore, in the structural features and in the combinations of elements described, without departing from the spirit of the invention as expressed in the appended claims. Also, it is desirable to add to the water which is applied to the back of the paper, some one of a number of wetting agents, one example of which is an ester of a sulfonated bi-carboxylic acid sold under the commercial name of Aresol," which agents tend to break down the surface tension and expedite the penetration of thepaper by the water.

The claims of this application are directed to the apparatus only as claims to the method will be found in applicants Patent 2,145,752, issued January 31, 1939, and based on application 11,142, filed March 14, 1935, of which application this is a division.

I claim:

i. A blue print machine for developing. a band of paper coated with light-sensitive material comprising, a frame, a plurality of rollers mounted in said frame under one of which said band of paper passes upside down with its uncoated side in contact with said roller, means for directing a spray of liquid against said roller whereby the latter moistens the back of said paper and whereby said liquid soaks through said band of. paper and causes initial development of said light-sensitive material while the same is traveling away from said roller, and means associated with said frame for washing said paper subsequently.

2. A blue print machine for developing a band of paper coated on one side with the usual blue print chemicals comprising, a frame, a printing station and a washing station each positioned in said frame, and a plurality of rollers between the two, under one of which said band of paper passes upside down with. its uncoated side in contact with said roller, means for directing a spray of water against said roller whereby the latter moistens the back of said paper and whereby said moisture soaks through said band of paper while the same is traveling from said roller toward said washing station and initiates the development of the. blue print, and a bath of water through which said blue print passes before reaching said washing station, to complete the development thereof. a

3. In a photoprint machine adapted for use witha band of sensitized paper, a frame, having a printing station therein and a washing station comprising a plurality of rollers mounted in said frame with which said paper contacts as it travels from one station tov the other, one of said rollers being mounted so that said paper passes the same with its unsensitized side in contact therewith, means for applying a developer to said roller to moisten said side, a tank for a developing solution mounted in said frame, through which said paper passes from said roller to said washing station, and means for guiding said paper through said tank with its coated side downwardly, to complete the development thereof without bleeding.

4. Equipment for applying a developer to a moving sheet coated on one side only with lightsensitive material and unwound continuously from a roll, comprising a frame, rollers supported thereby, means including said rollers for guiding .saidsheet on a predetermined path of movement during part of which the coated side of said sheet faces upwardly, three of said rollers being arranged horizontally in parallel relation with their axes spaced to form a triangle, the intermediate roller being at a lower elevation than the other two rollers and said sheet passing up and over the first roller to turn it face downwardly, then under said lower roller and then in contact with the third roller, and means for directing a liquid developer against the upper side of said intermediate roller.

5. A blue print machine as in claim 1, with the.

addition of a warm water supply to which said means for directing a spray of water is connected to accelerate the oxidation process.

6. A blue print machine as in claim 1 with the addition of means for applying heated vapor to the sensitized side of the paperduring the travel thereof from said roller to said washing station.

'7. A machine for developing a. ,.sheet having a light-sensitive chemical coating on one side thereof, comprising a frame, a roller mounted to move freely up and down in said frame to maintain tension on a loop of said sheet in which said-roller is supported with the coated side of said sheet in contact with the under side of said roller, a second roller mounted in said frame and spaced laterally from said first roller, around which second roller said sheet passes, with said coated side in contact therewith, to a third roller spaced laterally from said second roller in said frame, and a source of liquid developer between said second and third rollers located to apply said liquid to the upper and uncoated side of said sheet as it travels between said two rollers, whereby said liquid may soak through said sheet and initiate a reaction with the chemicals on the coated side thereof.

8. A machine as in claim "7 with the addition of a source of water mounted in said frame, and an adjacent roller over which said paper travels past said source whereby said print may be washed.

9. A machine as in claim 7 with the addition of a developing tank mounted in said frame having spaced rollers adjacent thereto with their lower portions submerged in the liquid developer therein, said rollers serving to guide said paper from one to the other beneath the level of said, liquid, to complete the development.

10. A machine for developing a sheet having a. light-sensitive coating on one side thereof comprising, a frame, three sets of transverse members in said frame one over the other to provide three stations, said lowermost station having three parallel rollers mounted in said transverse members in triangular arrangement, with .the apex of the triangle downwardly, an additional roller mounted in said frame, from which the paper travels to one of the two upper rollers of said triangle and over the same, thence downwardly under the middle roller and up wardly around the third roller, with the coated side thereof in contact with the .two upper rollers and having rollers to guide said moistened sheet from the lowermost station to the intermediate station and thence through the liquid in said tank with the coated side facing downwardly,

and means mounted in the upper station for

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