US1977166A - Apparatus for preparing films - Google Patents

Description

Oct. '16, 1934. A WI E 1,977,166

APPARATUS FOR PREPARING FILMS Filed Nov. 12, 1928 Patented Oct. 16, 1934 UNITED STATES PATENT OFFICE to Metro-Go ldwyn-Mayer Corporation, Culver City, Calif., a corporation of New York Application November 12, 1928, Serial No. 318,892 Claims. (01. 91-18) This invention relates to a method of preparing and treating films and particularly strip motion picture and sound recording films for projecting and printing purposes. The invention 5 also relates to an apparatus particularly adapted for use in preparing and treating strip film in accordance with this invention. The method and apparatus embraced by this invention is particularly adapted for conditioning new strip film for projecting and printing purposes.

Substantially all projection machines used in projecting strip film are equipped with shoes which press against the film near its edges (ordinarily by means of springs) and thereby maintain the film in a fiat position over the projection aperture. These shoes together with adjoining portions of the projecting apparatus become hot during projection, partly because of the friction between the shoes and the film.

Although the presser shoes are of highly polished metal, it is found that the shoes adjoining the emulsion side of the film will pick up minute quantities of emulsion, gelatin and foreign matter, the emulsion adhering to the shoes and building up in little mounds so as to form hard, sharp particles which then begin to out not only the emulsion of subsequent portions of the, film but even the celluloid backing of a film strip. As a result of this cutting action the film is often torn and the sprocket holes ripped open. As a matter of fact not more than about fifty feet of new fully dried motion picture film can be run through a projecting machine without having a sufllcient' quantity of emulsion accumulate upon the shoes of the projecting machine to cause cutting of the film. When such accumulation and cutting becomes audible to the projection machine operator, he must stop the machine and expose and clean the shoes of the accumulated emulsion before proceeding with projection of the film.

It has been possible to partly correct this condition by applying a wax to the film particularly near the edges thereof, but heretofore the wax was easily rubbed oif and new applications had to be made repeatedly during the life of the film. Furthermore it was found that large amounts of wax could not be applied as the heat of the projecting machine would cause the wax to spread unevenly over the image recorded upon the film, collect foreign matter, and impair the image, often rendering the films unfit for exhibiting pur- The objections to the use of wax in the customary manner are particularly pronounced on 50 those films on which both sound and views or images are recorded as the sound recording is very close to the edge of the film and reproduction is distorted if the wax spreads thereinto.

An object out this invention is to provide an apparatus for treating and conditioning 50 Another object is to provide an apparatus for applying a treating agent to a film and then impregnating said film with said treating agent. A still further object of this invention is to disclose and provide means whereby frictional pressure is utilized in impregnating the films with a treating agent to prolong their life.

Other objects, advantages and uses of this invention will become apparent from the following detailed description of the method employed and of an apparatus particularly adapted for use in carrying out said method. In describing the method, reference shall be made to the appended drawing in which a preferred form of apparatus is shown diagrammatically. 7

In the appended drawing:

Fig. 1 is an elevation showing one form of apparatus which may be used in carryin out this invention, the apparatus being shown more or less diagrammatically. 3

Fig. 2 is a plan view of ironing means shown in elevation in Fig. 1.

Fig. 3 is a vertical section taken through the ironing means shown in Fig. 1 along line 33.

Fig. 4 is a plan view of means for applying an oily treating agent to a film.

The method embraced by this invention generally consists of applying an oily treating agent to a strip film, the treating agent being preferably applied in quantities insuflicient to completely cover said film, that is, an excess of oily treating agent is preferably not applied, but only sufiicient to impregnate the emulsion upon later treatment.

The method then contemplates impregnating the film with said applied oily treating agent and in distributing said treating agent over predetermined portions of the film so that-the treating agent impregnates the emulsion carried by the film. The impregnating and distributing step may be called ironing or burnishing.

By an oily treating agent as used herein is meant any wax, oil, fat or other material which is suitable for the purposes of this invention. For example, paraffin wax, hydrogenated vegetable oils, and sterols, (either alone or with solvents) and vegetable, animal or mineral oils may be used. When hydrogenated oils, parafiin wax, or other fatty bodies are used which are solid at ordinary temperatures, such waxes and fatty bodies may be heated and reduced to a liquid condition before 119 being applied to the strip film. When liquid oils are used it may not be necessary to heat the same before applying to the strip film although ordinarily it is desirable to heat even liquid oils so as to assist in impregnating the emulsion on edge areas of the film with said oils. Mineral oils of the lubricating type and of a relativelylow viscosity are preferably used in treating and conditioning films in accordance with this method.

After said 011' or other oily treating agent has been applied to the film, said oil may be caused to be distributed upon and thereby diffused throughout the emulsion by subjecting the strip film bearing the oily treating agent to heat and pressure.

The heat renders the oily treating-agent more fluid and reduces its viscosity while the pressure causes the oily treating agent to be distributed over and impregnate the emulsion.

During projection, films very often pick up excessive quantities of oil from the machines and sometimes oil is liberally applied so as to counteract, somewhat, the difficulties enumerated hereinabove. Such oil is generally dirty and is absorbed by the emulsion and gelatin, impairing the clarity and distinctiveness of the images recorded thereon and is not absorbed uniformly by the films. By burnishing and treating films in accordance with this invention, however, the emulsion is impregnated uniformly with a clean, oily treating agent which prevents subsequent absorption of dirty machine oil. Furthermore the burnishing step apparently hardens and lubricatm the emulsion surface thereby substantially preventing scratches upon the film. Again, the

treatment herein described appears to give depth and definition to the recorded images, when the entire film area is treated. It will be understood that the method embraced by this invention may be applied to all films, whether negatives or positives, and either the entire emulsion side of a film may be treated or only the edge areas. For purposes of illustration, the subsequent description will be limited generally to apparatus adapted to be used in treating edge areas of a strip film.

Referring to Figure 1, the film 1 to be treated and conditioned may be unwound from a suitable reel 2, passed over a means for applying an oily treating agent 3, then over the ironing means 4 and eventually wound up upon a second reel 5. It is understood that the apparatus may assume various forms and embody numerous modifications.

The means for applying the oily treating agent may consist of a container 3 having a shaft 6 rotatably journaled therein, said shaft bearing discs 7 mounted upon the shaft 6 in spaced relation. Suitable means for driving the shaft 6 and thereby driving the disks 7 may be provided although such means are not shown. The device may be provided with a cover 8 provided with slots 9 through which the discs protrude, the cover 8 being hingedly attached to the container 3 as indicated at 10. The container 3 provides storage means for the oily treating agent, the level of the oily treating agent within the container 3 being indicated at 11.

Means may also be provided for heating the container 3 and the oily treating agent therein, such means consisting, for example, of an electrical resistance coil 12 positioned in the lower portion of the container 3 and supplied with electrical energy from a suitable source such as the lines 13. A rheostat 14 or other means for controlling the current supplied to the resistance coil 12 may be provided. It will be understood that other means for heating the oily treating agent in the container 3 may also be used.

The spool 2 from which the film to be treated is supplied to the apparatus may be provided with a small drum 15 against which a brake shoe is may be yieldably urged by means of a spring 17 positioned around a rod 18 slidably held in suitable mounting 19. The spring 17 exerts its force against a small collar 20 mounted upon the rod is thereby yieldably urging the rod is toward the 5 drum 15. The brake shoe 16 may be slidably mounted upon the upper end of the rod 18, a small compression spring 21 being introduced between the end of the rod 18 and the brake shoe 16. The lower end of the rod 18 may be pivotally connected as at 22 to a lever 23 pivotally mounted to a suitable framework or stable portion of the appartus at 24. The spring 1'! should be so adiusted so as to cause the brake shoe 16 to always exert a positive braking efiect upon the drum 15 and uphold the lever 23 except as hereinafter described.

A pivoted .lever 25 pivotally connected at 28 to the framework or other support may be positioned about the lever 23, one end of the lever 25 being provided with a round nose 27 adapted to rest upon the free end of lever 23. The opposite end of lever 25 may carry a guiding spool 28 loosely pivoted in the lever 25. The strip film 1 from the spool 2 is preferably passed under the 106 guiding roller 28, then over a guiding roller 29 loosely mounted upon a spindle adjoining the means for apply n an oily treating agent 3 so astoguidethefllmluponthediscs'lofsaid means 3, and then under a second guiding roller 30 loosely moimted upon a spindle on the other side of the oil applying means 3. The film 1 is then passed through the ironing means 4 which isshowninli'igs. 1,2and 3.

The ironing or burnishing means may com- 116 prise a pair of heated shoes 31 in spaced relation, the shoes 31 being heated in any suitable manner. For example, the ironing shoes 31 may be heated by conduction from metallic housing 32 heated internally by electric heating means 33 supplied with electrical energy from line 13, the electrical current being regulated by suitable means such as the resistance means 34. The ironing shoes 31 are preferably made of highly polished metal and said shoes may be removably attached to the housings 32 by means of tap bolts 35 or the like.

A pair of presser shoes 36 may be operatively positioned above the ironing shoes 31, said presser shoes 36 being yieldably urged toward the ironing shoes 31. This may be accomplished by providing a gate 37 pivotally connected to the framework or to the housing 32 of the ironing shoes 31 as at 38, the hinged connection 38 being made with extensions or lugs 39 from the housing 32. The gate 37 may be provided with longitudinal slots 40 adapted to loosely receive the presser shoes 36. The presser shoes may be provided with longitudinal extensions 41 so as to prevent said shoes from dropping through the slots 40. The presser shoes 36 may be yieldably urged toward the ironing shoes 31 by means of transverse leaf springs 42 contacting with the upper surfaces of the presser shoes 36, the leaf springs 42 being adjustably mounted above the gate 37 by means of tap screws 43 passing through the springs 42 and threadedly engaged with the gate 37. The presser shoes may take the form of rotatable discs mounted upon a shaft yieldably urged toward the ironing or burnishing means.

Means may be provided for operatively positioning the gate 37 and presser shoes 36 carried thereby with respect to'the ironing shoes 31, such means including a suitable latch 44 pivotally connected to the framework or to the housing 32 as at 45. The latch 44 may be adapted to contact with a lug 48 extending from the gate 37, a spring 47 being connected to the latch 44 and to a suitable support such as the framework 32 so as to yieldably urge the latch 44 against the lug 46 and maintain the latch in closed position.

The film 1 to be treated may be passed through the apparatus hereinabove described by means of a suitable driven sprocket wheel 48 mounted beyond the ironing means 4. The treated mm from the ironing means 4 may be passed over an idler guide roller 49, then over the driving sprocket 48, then under a tension roller 50 and then to the reel 5 upon which the treating film is wound.

In operation it is desired that the film being treated be passed through, the apparatus under a substantially constant tension and this is accomplished by means of the brake shoe 16 bearing against the brake drum 15 carried by the reel 2. If the film between guide rollers 29 and '49, for example, is slack, the lever 25 pivots on 26 so as to drop the guide roller 28 thereby enabling the spring 17 to raise rod 18 and press the brake 16 against the brake drum 15. As soon as this braking action is exerted upon the brake drum 15, the speed of the reel 2 is diminished and the film being fed therefrom is placed under.

tension. If, however, the tension of the film between rollers 29 and 49 or between rollers 28 and 49 exceeds a certain predetermined point, such tension will cause the outer end of lever 25 carrying the roller 28 to move upwardly, the nose 27 of the lever 25 pressing down upon the end of lever 23 thereby causing the lever 23 to pivot upon the pivot 24 pulling the rod 18 downwardly. This downward movement of the rod 18 is imparted in part to the brake shoe 16 thereby reducing the braking effect upon the drum 15 and allowing the reel 2 to rotate more easily on its shaft and thereby reduce the tension of the film 1 passing through the apparatus.

In operating the above apparatus and carrying out the method herein described, strip film to be treated is supplied from a strip reel 2 and passed under and over the spools 28 and 29 so as to press the emulsion side of the film 1 to the oil applying discs 7. The film is then threaded under the guiding roller 30 and through the ironing machine 4 between the presser shoes 36 and the ironing shoes 31. The film is then threaded under the guide roller 49, over the driving sprocket 48, weighted roller 50 and into the reel 5. It will be understood that the reel 5 is driven so as to wind up the threaded film thereon although such driving means are not shown.

The oil applying means 3 are then filled with a suitable oily treating agent such as, for example, a mineral lubricating oil. The heating coils 12 are then energized so that the oil within the container 3 is brought up to the required temperature.

The heating coils 33 in the ironing device 4 are also brought up to the required temperature and the driving mechanism then started so as to pass the film through the apparatus. The discs 7 are rotated by means of the shaft 6, the direction of rotation depending somewhat upon the viscosity or fluidity of the treating agent being applied. Preferably, however, the discs 7 are rotated in the same direction as the film 1 passing thereunder, although the peripheral speed of the discs 7 may be materially slower than the lineal speed of the film passing thereunder so that only a very minute quantity of oil or treating agent carried by the discs 7 from the lower portion of the chamber in which they rotate is applied to thefilm.Asshownin1"lg'.4thediscs7are preferably in such spaced relation that the treating agent is applied to the edge areas of the film only and substantially in the center oi said edge areas. In view of the fact that the edge areas bear sprocket holes 71, the treating agent is only applied to those portions of the film between such sprocket holes. The film carrying the treating agent is then passed into the ironing device 4 where it comes in contact with the heated ironing shoes 31. The heated ironing shoes 31 which are of greater width than the discs 7 thereby tend to spread the thin line or bead of oily treating agent over the entire edge areas. The film 1 is furthermore pressed against the ironing shoes 31 by means of the presser shoes 36 acting as hereinabove described thereby assisting in distributing the treating agent over the entire edge areas of the film.

The concerted effect of the heated ironing shoes 31 and the pressure applied by presser shoes 36 results in a thorough impregnation of the edge areas with the treating agent, the treating agent being driven into the emulsion. After such treatment the treated film is wound up on the reel 5 1 and is ready for projecting purposes.

For ordinary purposes when mineral oil is being used for treating films in accordance with the hereinabove described method, relatively low temperatures are employed in the oil applying de- 1 vice 3 and in the ironing device 4, for example, temperatures of 100 to about 150 F. may be used depending somewhat upon the speed with which film is passed through the machine and the character of the oily treating agent being applied. 1

A film treated in accordance with the hereinabove described invention may be used for projecting purposes for a relatively long period of time without being rewaxed or retreated and may be projected a great number of times without hav- 12g without departing from the spirit of the invention, it being understood that all changes and modifications which come within the scope of the invention defined in the appended claims are embraced thereby.

I claim:

1. In an apparatus for treating and conditioning films, the combination of spaced disc means for applying a liquid treating agent to edge areas of the emulsion side of a continuous motion picture film, spaced stationary metallic ironing means adapted to contact with edge areas of the emulsion side of the film, said ironing means being of greater width than said disc means, means for heating said ironing means, means for passing continuous film over said disc means and emulsion side of the film, means for heating said ironing means, and means for passing continuous film from said applying means over said ironing means with the emulsion side of the film in contact with said ironing means.

- 3. In an apparatus for treating and conditioning continuous motion picture films, the combination of means for applying an oily treating agent to the emulsion side of a continuous film, a pair of parallel spaced stationary metallic ironing means adapted to contact with edge areas of the emulsion side of the film, means for heating said ironing means, means for passing continuous film from said applying means over said ironing means with the emulsion side of the film in contact with said ironing means, and means for causing frictional pressure between said film and ironing means whereby the oily treating agent is caused to impregnate said emulsion side of the film.

4. In a device for treating and conditioning films, the combination of a pair of parallel spaced stationary metallic ironing means adapted to contact with edge areas of the emulsion side of a continuous motion picture film, means for heating said ironing means, a frame above said ironing means, said frame being provided with slots paralleling said ironing means, a presser shoe movably positioned in each of said slots, and spring means for yieldably ram said presser shoes toward said ironing means.

5. In a device for treating and conditioning films, the combination of a pair of parallel spaced stationary metallic ironing means adapted to contact with edge areas of the emulsion side of a continuous motion picture film, means for heating said ironing means, a frame above said ironing means, said frame'being provided with slots paralleling said ironing means, a presser shoe movably positioned in each of said slots, spring means for yleldably urging said presser shoes toward said ironing means, and means ior passing continuous film between said ironing means and presser shoes.

ANTHONY G. WISE.

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