US3093052A - Photographic processing apparatus - Google Patents

Description

June 11, 1963 w. c. BURNER ETAI. 3,093,052

PHOTOGRAPHIC PROCESSING APPARATUS Filed Dec. 3. 1959 2 Sheets-Sheet 1 cHm STOPHER LUCAS ATTO June 11, 1963 W. C. BURNER ETAL PHOTOGRAPHIC PROCESSING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 3. 1959 FIG?) INVENTORS,

WILLARD C. BURNER SEYMOUR 1.. HER SH CHRISTOPHER LUCAS ATTO NE United States Patent 3,093,052 PHOTOGRAPHIC PRUCESSING APPARATUS Willard C. Burner, Lincroft, Seymour L. Hersh, Freehoid,

and Christopher Lucas, Long Branch, NJL, assignors to the United States of America as represented by the Secretary of the Army Filed Dec. 3, 1959, Ser. No. 857,238 1 Claim. (Cl. 95-94) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.

This invention relates to method and apparatus for processing photo sensitive materials and provides particularly for continuous rapid processing of strip type materials.

The techniques involved in the invention are adapted to the use of elevated temperature development and fixing in which case it is possible to completely process as much as 100 feet of 35 millimeter film per minute. However normal temperature processing may be executed at relatively fast speeds by the use of the apparatus of the invention.

As will appear hereinafter the invention is adaptable to various processing systems such as the so-called monobath system and the stabilization technique.

The apparatus of the invention makes possible successful processing at high speed and is briefly described as follows. A plurality of processing wheels are rotatively mounted upon one face of a vertical panel of chemically resistant material which physically separates the chemical manipulating elements from the driving and control mechanism. The wheels are arranged to be sequentially contacted by the strip to be processed along a portion of their periphery.

The whole apparatus may be operated Within the confines of a dark room or may be enclosed in a light tight casing of its own not shown. In the latter case suitable control adjustments will be made accessible outside the casing.

Each wheel is partially submerged in a tank of processing solution and is rotated by suitable driving means. Guiding means is provided to control the lateral position of the strip upon the roll. The faces of the processing wheels are treated to enable them to pick up solution and apply it to the emulsion side of the strip only. The width of the face of the applicator wheels is less than the total width of the strip. In this manner development of the exposed main area of the film is processed while the narrow margins are not processed. This technique insures that no solution will accumulate on the back of the film to cause stains, streaks or other imperfections and also eliminates an all over Washing step.

The peripheral faces of the applicator Wheels maybe treated or covered with material which serves to absorb solution for transfer to the film and at the same time protect it from scratches and imperfections while being processed. A valuable feature of the invention lies in the formation of a series of narrow deep slots extending transversely across the face of the wheel. These slots function to reduce the drag on the strip which may become excessive. The drag is induced by the film of solution between the contacting surfaces of the wheels and strip. Additional features of the invention will be described hereinafter in connection with a detailed description thereof.

A primary object of the invention is to provide an extremely rapid system for processing photographic images.

A further object of invention is to provide a photo processing apparatus capable of rapidly processing photo "ice sensitive materials and wherein most of the variables effecting the quality and characteristics of the finished image are under control.

A still further object of the invention is to provide safe and effective means for high speed processing of photo materials at high level temperatures.

A further object of the invention is to provide very compact means for rapidly processing long lengths of photo sensitive materials.

A still further object of the invention is to provide a processing apparatus which is rapid in action and which lends itself to the practice of a variety of techniques.

A further object of the invention is to provide a substantial economy in consumption of solution.

Other objects and features of the invention will more fully appear from the following description and will be particularly pointed out in the claim.

To provide a better understanding of the invention specific embodiments thereof will be described in connection with the accompanying drawings wherein:

FIG. 1 is a side elevation of an apparatus embodying the invention.

FIG. 2 is a partial diagrammatic plan view of the apparatus showing the driving means.

FIG 3 is an enlarged vertical cross section on line 33 FIG. 1 showing the detail structure of the applica tor Wheels.

FIG. 4 is a detail showing the structure of squeegee means 'for the applicator wheels.

FIG. 5 is a detail showing of the structure mounting the roll covering to an applicator wheel.

The arrangement of the elements of the device as shown in the drawings has been found to be satisfactory. It should be understood however that other suitable arrange ments may be made without departing from the spirit and scope of the invention. Desirably the rotating processing elements are mounted upon a vertical panel 10 which in turn is secured to a suitable base 11. The panel serves not only as a support but also as a shield to separate the driving elements from the processing elements thus to protect the driving elements from corrosion.

A plurality of applicator wheels are rotatively supported on the panel 10 the number of such Wheels being determined by the processing steps required for a given processing system. As shown in FIG. 1, there are three applicator wheels. The first wheel from left to right is the developer applying wheel 12, the second wheel 13 is for fixing and the third wheel 14 is for rinsing or other finishing operation. Other functions may be assigned to the wheels.

Each wheel is supported upon and driven by suitable shafts 15, which are journaled in bearings 16 fastened to the panel 10. The shafts extend outward from both sides of the panel and are connected to the drive mechanism at one end and receive the applicator wheels at their other end. Suitable coupling arrangement is made between the shafts and the wheels. In the embodiment shown the shafts are squared in cross section to be received in snugly fitting square apertures in the wheels. Means are also provided to detachably lock the Wheels upon the shafts such as the wheel securing device 17 having a locking arm movable from its wheel detaching position in alignment with the shaft, to its locking position transverse to the shaft where it engages the hub of the Wheel to retain it in operating position.

Processing tanks 18, 19 and 29, of stainless steel or any non-corrosive material are provided into which the applicator wheels 12, 13 and 14- respectively dip to pick up solution to be fed to the strip. The tanks may receive solution thru a piping system from a larger supply container or as shown each tank may be removable and adapted to be filled by manual means. They may be hung upon the panel or rest upon the base 11. Each tank is provided with an electric heater 21 having temperature controlling means.

The wheels as shown are about six inches in diameter and have a peripheral face of a width to receive a conventional edge perforated 35 mm. film strip. Other wheels can be supplied and placed on the shafts to accommodate other sizes of film or printing paper strips. The diameter of the wheels is determined by the size of the equipment, capacity of solution tanks, the desired maximum required degree of contact between the film and wheel faces as it progresses thru its processing stages and other factors which are matters of design. The driving means will subsequently be described in connection with the description of operation of the device.

Processing solutions are applied only to the emulsion side and only to the actual picture area. No solution is applied to the margins of the strip. To accomplish this specific result the exposed film or paper strip 23 is wider than the faces of the wheels 12, 13, and 14. The strip is fed from a supply reel 24 to the first applicator wheel 12 passing over a guide roll 25 and thence along a portion of the upper periphery of the wheel 12 and is led off this Wheel by a second guide roll 26 from where it passes to wheel 13. It then passes to guide rolls 2.7 and 23 and thence to the wheel 14 after which it passes around guide roll 29. The guide rolls are undercut to avoid contact with the center portion of the strip. From the roll 29 the strip is fed to a driving sprocket 3t engaging the edge perforations of the strip. From the sprocket the Strip is led to a suitable drying device 31. The strip when dry is then ready for use.

Means are provided for varying the contact area between the wheels and the film strip. A suitable means for accomplishing this adjustment is to rotatively support the guide rolls upon removable stud shafts 32 having their threaded inner ends projecting thru the panel 10 and provided with a nut or thumbscrew to effect detachable mounting upon the panel.

A row of apertures 33 are provided in the panel equidistant from each roll axis and within which the roll support shaft 32 may be received to provide the required degree of wrap of the strip around the wheel face. The guide rolls are provided with side flanges between which the strip is caused to track properly while passing over the applicator wheels.

A further operating facility is provided for prewetting the emulsion prior to its development. Any suitable means may be provided for this purpose such as the roll 34 of the same Width as the applicator wheel, which is so positioned that it will engage the emulsion side of the strip before it reaches the Wheel 12. The roll desirably is covered with absorbent material and dips into a water tank 35. A hold down roll 34X is removably mounted on the panel 10 and engages the back of the strip 23 to press it into contact with the wheel 34. In this manner water is conveyed to the emulsion on the strip. This prewetting step is used in certain developing techniques the details of which will be set forth hereinafter.

The roll 34 is operated by a variable speed reversible drive mechanism 22. It is important to apply the water evenly and rapidly to the strip. This is accomplished by driving the roll either at a peripheral speed faster or slower than the linear speed of the strip. Optimum results are obtainable by accurate adjustment of the roll speed. If the peripheral speed of the roll is equal to and in the same direction as that of the strip, the finished image may show an uneven pattern imparted thereto by the pattern of the surface of the roll.

The ability to reverse the rotation of the roll 34 and also the applicator wheels provides flexibility in adjusting the total drag on the strip during its progress thru the apparatus. By selecting the proper rotation for these elements the drag upon the strip due to one may at least partially cancel that due to another. Thus the total drag may be kept to minimum.

it is also desirable to provide squeegee rolls 36 to re move surplus solution from the peripheral faces of the applicator wheels as they carry solution from the tank toward the strip. The squeegee must be positioned to engage the wheel at a point to prevent the surplus solution rom reaching the film such as between the surface of the solution and the first line of contact of strip and wheel. The contact pressure of the squeegee roll is adjustable to insure the correct quantity of solution reaching the strip emulsion. This adjustment may be provided by mounting each squeegee roll on a shaft 37 which is secured to a swinging arm 38 having a shaft 39 pivoted within the panel 19 to permit the roll 36 to move toward and from the applicator wheels.

The pivot shaft 39 extends thru the panel and has an arm 46 secured thereto, to which is fastened one end of a spring 41, the other end of which is fastened to a stud 4-2. The stud is adjustably secured in a slot 43 in the panel thereby to provide adjustment of the spring tension and thus to vary the pressure of roll 36 on its applicator wheel. Other means may be devised to mount the squeegee rolls 36.

Two squeegee rolls 36 are provided for applicator wheels 13 and 14 and one for wheel 12. In addition latching pins 44 are provided. These pins are removably mounted on the panel 10 and project into the path of the arms 40 on the squeegee control devices. When in inactive position they lock the rolls 36 out of action as shown in dotted lines FIG. 4. This control of the rolls 36 is provided to permit selective operation thereof thus to prepare the apparatus for various modes of operation. In some instances the direction of operation of certain of the applicator wheels are reversed as pointed out above therefore the proper roll 36 must be rendered operative and the other rolls inoperative.

Any suitable means may be used to drive the applicator rolls. As shown in FIG. 2, the wheels are driven by re versible variable speed electric motors 45 and 46 secured to the base 11. Motor 45 drives applicator wheel 12 thru a speed reducing mechanism 47 connected to the drive shaft of the wheel. Motor 46 drives wheels 13 and 14 respectively thru speed reducing mechanisms 48 and 49 coupled to the drive shafts of the Wheels.

Desirably the roll 12 is driven in such direction that its periphery moves in the opposite direction to that of the movement of the strip and moreover since the mo tor 45 is a variable speed motor the degree of counter motion is adjustable. Desirably the strip is drawn thru the apparatus by means of a sprocket Wheel 30 engaging the edge perforations of the strip. If no perforations are present the sprocket may be replaced by a friction type drive wheel engaging the edges of the strip. The sprocket 30 is driven by the motor 46 in any suitable manner such as by the chain and sprocket drive 51. Desirably a hold down roll may be provided for :ZnJaintaining engagement between the strip 23 and sprocket The wheel 13 is driven in the same direction and at a peripheral speed faster than that of the travel of the strip. The roll 14 is driven in a direction counter to that of roll 13. To provide for such change in direction a reversing mechanism 52 is inserted in its drive shaft. Other suitable driving means for the strip and applicator wheels may be used.

An important feature of the invention resides in provision for feeding controlled amounts of solution to the strip being processed. Accurate and uniform feeding of processing solutions is highly desirable. This is especially true in the present invention where high speed is a main objective. A positive flow of solution in adequate amount must be supplied but not in excess thereof because waste of solution and uncontrollable distribution thereof would render the apparatus ineffective and inetficient.

The above described squeegee rolls 36 constitute a portion of the control means for applying solution to the strip 23. An important and novel feature of the invention resides in the further improvement of the solution applying means. This further improvement is directed to the provision of the most effective peripheral surface structure for the wheels 12, 13, and 14. Consideration of many factors entered into the development of the most effective means for carrying solutions from their tanks to the surface of the strip along the periphery of the applicator wheels. It was found that an effective carrier means was to cover the wheel surfaces with a fabric having the ability to absorb substantial quantities of solution and to feed the solution to the emulsion on the strip, thruout its traverse of the contact areas of the wheel, at a uniform rate. The fabric must also be soft to avoid abrasion of the softened emulsion which, at high temperatures in particular, is subject to damage. Such a covering is shown in FIG. 3 and consists of a strip of fabric 53 covering the wheel face from edge to edge. The fabric is composed of a relatively thick base portion 54 and an interwoven short pile structure 55 presenting the desired soft contact between strip and wheel. This fabric absorbs a substantial volume of solution from a tank and applies it evenly to the strip by contact of its pile structure therewith, the operation being similar to painting with a soft bristle brush. The margins 56 of the strip beyond the edges of the roll do not receive processing solution.

When applicator rolls are covered as shown in FIG. 3 solution of normal concentration may be used and prewetting is not necessary but may still be used. The water feeding roll 34 may be rendered inactive by removing the contact roll 34X and the film strip led from its supply roll 24 directly to the guide roll 25 and thence over the upper portion of the roll 12 after which the strip follows the path of travel set forth above. The roll 12 performs the developing operation by carrying heated developer from the tank 18, upward to the strip 23. Surplus solution is controlled by the squeegee 36- whose contact pressure may be adjusted as described above.

The tank 19 contains a fixing solution heated by its heater 21 and applied to the strip by the roll 13 as in the developing step. In the specific procedure herein described above the roll 13 is driven to provide faster peripheral speed than the strip. Surplus solution is controlled by its left hand squeegee 35 while its other squeegee is latched out of operation. The tank 20 contains rinse water which acts to remove unwanted chemicals from the emulsion of the strip and surplus moisture is controlled by the right hand squeegee. When dried the strip is clear and free of defects and stains and moreover the limited amount of moisture contained in the emulsion is rapidly removed with a minimum of heating currents consumed by the drying chamber 31.

The slots 57 in the rolls 12, 13, and 14 extend transversely across their faces and are cut deeply radially inward. These slots function to relieve drag on the strip and to aid in feeding solution to the roll covering 53 when it is immersed in the solution. Suitable means are provided to clamp the roll covering 53 upon the roll. One such means is to provide a slot in the face of the roll within which the ends of the material are held by a wedging block 58.

Guide blocks 59 are fastened to the panel in position to engage the inner edge of the strip 24 and guide rods 60 are anchored in the panel and bent downward to embrace the outer edge of the strip. The strip is thus accurately guided and centered on the rolls. The guide means may present any portion of the inner area of the strip to the wheels.

The various elements of the apparatus may be operated in various ways other than in the above specified manner to enable different types of sensitive materials to be processed for example development, shortstop and fixing may be sequentially executed by the wheels 12, 13, and 14. Additional applicator wheels may also be added when necessary.

The applicator rolls may be made of any suitably noncorrosive material such as hard rubber or various synthetic materials such as polyethelene. As above pointed out excellent results are obtained by covering the wheel faces with selected fabrics. However it may be found desirable to. use smooth faced rolls without covering. When smooth rolls are used only a small amount of solution adheres to the wheels which may not :be sufiicient to properly process the emulsion particularly at the high speeds for which the invention is adapted.

To overcome this deficiency special formulations are used for the processing solutions wherein the chemicals are incorporated at high concentrations. The higher concentration of the solution applies a much higher processing potentiality to the emulsion. However, the high concentration solution does not of itself readily permeate the emulsion. To overcome this deficiency the prewetting roll 34 is activated by mounting the roll 34X in position and the strip passed between it and the roll 34. The emulsion thus moistened will more readily accept and diffuse the processing chemicals to provide fast and uniform action of the solution.

Under certain conditions it is desirable to use smooth faced uncovered applicator rolls because there is no covering material to replace when it "becomes worn. Also there is less chance of picking up harmful small abrasive particles and the drag upon the strip is lessened.

A highly effective use of the invention is in the practice of the so called stabilization process as set forth in US. Patent No. 2,696,439 wherein photo sensitive material is first developed in any suitable manner and then instead of fixing the material the unexposed and nude veloped silver halide remaining after development is rendered neutral and transparent.

The present invention provides a practical manner in which this process may be greatly speeded up. By conducting the processes at elevated temperatures the development time is shortened and in addition the stabilization time may be greatly reduced. In normal practice the stabilizing or clearing step consumes more time than the development. It follows that time reduction of this step is most important in reducing the total processing time.

Stabilization is accomplished by bathing the material in a solution of thiourea. Higher concentrations of this compound tends to speed up the stabilization step. However, there normally is a limit to the degree of concentration because when too much thiourea is used crystallization of the excess thereof takes place upon the emulsion surface which degrades the quality of the image.

In practicing the stabilization process upon the apparatus of the invention a high temperature development step is followed by a high temperature stabilization step wherein an increased concentration of thiourea is used which greatly reduces the time for clearing of the image. Under these conditions an abnormal amount of thiourea is present on the emulsion surface and if left to dry would not be tolerable. Therefore the last processing wheel 14 having a fabric covering thereon is used to wash the emulsion surface with water which removes the surplus thiourea. This washing step can not be done by any prior known means but is successfully accomplished by the apparatus of this invention.

In the present invention each step in the process is executed very rapidly. As a consequence the emulsion does not swell and soften to the extent it would at conventional processing speeds. This is especially true in the case of the high thiourea concentration as above stated which may be 11% at 68 F. which is the saturation level. Temperatures used maybe as high as or higher in which case thiourea would be added to produce substantial saturation. It is possible therefore to safely wash off the excess of thiourea in the last step of the process. Thus the whole operation is greatly speeded up. It should be noted that in the event that a greater or less number of processing wheels than those shown and described are provided, the step of removing surplus thiourea or any chemical appearing in excess upon the strip may be removed by a washing wheel arranged to follow the final processing step.

What is claimed is:

Apparatus for continuous processing of photosensitive strip materials comprising a plurality of rotatively mounted solution applying wheels having a solution absorbing soft fabric peripheral face, a solution containing tank for each wheel into which a portion of the wheel is submerged, a supply roll containing the strip to 'be processed, means to guide said strip into successive peripheral contact with a portion of the unsubmerged periphery of said wheels, squeegee means acting on the periphery of said solution applying wheels to prevent the passage of excessive solution from said tanks to the film strip, a driving system to drive said wheels consisting of at least one film strip feeding roll having means to advance the film through the apparatus at a given speed independently of the peripheral speed or direction of rotation of certain of said wheels, variable speed driving means for said wheels having means for independently reversing the rotation of some of said wheels, said driving system driving said wheels at different speeds and in diiferent relative directions of rotation to reduce excessive drag on the film strip and to provide for applying variable amounts of solution per unit area to said strip at selected solution applying wheels and wherein at least some of said solution applying Wheels are provided with a plurality of narrow slots extending from the periphery of the wheel radially inward in a plane parallel to the wheel axis acting to relieve the tendency of the strip to adhere to the wheel.

References Cited in the file of this patent UNITED STATES PATENTS

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