US2791788A - Device for cleaning photographic films and similar articles, especially motion-picture films - Google Patents

Description

M y 1957 E. HAUSDORF ,7 88

DEVICE FOR CLEANING PHOTOGRAPHIC FILMS AND SIMILAR ARTICLES, ESPECIALLY MOTION-PICTURE FILMS Filed June 7, 1955 2 SheetsSheet 1 IN VEN TOR.

' M y 1957 E. HAUSDORF 2,791,788

DEVICE FOR CLEANING PHOTOGRAPHIC FILMS AND SIMILAR ARTICLES, ESPECIALLY MOTION-PICTURE FILMS Filed Juia e 7, 1955 2 Sheets-Sheet 2 Ha. f

XXX (X INVEN TOR.

DEVICE FOR CLEANING PHOTOGRAPHIC FILMS AND SIMILAR ARTICLES, ESPECIALLY M- TEQN-PIQTURE FEMS Erich Hausdorf, Ottawa, Ontario, t'ianada Application June 7, 1955, Serial No. 513,741

Claims priority, application Germany Lluiy l, 1954 7 Clmms. (Cl. -100) This invention concerns a device for cleaning photographic films and similar articles, especially motion-picture films.

According to the present invention, the device consists of a rotatably arranged roller or pulley over which the film to be cleaned is guided, whereby the film is subjected only to manipulation by means of rollers with the exclusion of friction and moisture, the roller means being coated with an absorbent substance, which during the guiding of the film over the cleaning rollers undergoes a change of form similar to that caused by a kneading action.

The absorbent substance may conveniently consist of a silicon putty (bouncing putty).

A further feature of the invention resides in mounting the cleaning roller on a pivotal arm on a vertically arranged plate and forming it across the breadth of a film with a channel for the reception of the silicon putty coating. When the device is not in use, this coating of the cleaning roller can, according to the invention, be covered by means of a foil-, paper-, or the like strip or by means of a removable sleeve.

The mounting plate for the roller is advantageously formed, according to the invention, as a revolving plate or disc and is mounted on the base of the device in such a manner that on insertion of the film into the cleaning device the revolving plate or disc is so rotated that the film extends in a taut condition between lateral guiding rollers when the cleaning rollers are turned away, but after the revolving plate is turned back into an operative position and fixed relative to the base, the film also becomes wound around the cleaning rollers.

According to a further feature of the invention, two rollers or pulleys are each mounted on a pivotal arm on the vertically arranged revolving pl te, and each roller possesses a channel corresponding to the breadth of the film, each channel serving for the reception of a coating of silicon putty. The two cleaning rollers or pulleys are so arranged on the revolving plate that on insertion of the film into the cleaning device, the plate can be so positioned that the two cleaning rollers lie perpendicularly one over the other and the film runs in a taut condition between the lateral guiding rollers and said two cleaning rollers. After rotation of the revolving plate and fixing thereof relative to the base, however, the film becomes wound around the two cleaning rollers in an S-shaped loop.

The device proposed by the invention may advantageously be so constructed that tension springs engage on the pivotal arms to press the arms against stops, and in the case of excessive tension on the film provide for a pendular play movement of the cleaning rollers.

It is also possible within the scope of the invention to mount one of the two cleaning rollers directly on the revolving plate and the other roller on a pivotal arm, whereby the arm is itself pivotally mounted on the revolving plate and is subjected tot-he action of a tension sp Photographic films and particularly motion-picture films are afflicted with the disadvantage of dust, dirt, grease spots, oil stains, fibre particles, finger prints, etc., affecting the transparency of the film, so that frequent cleanin becomes necessary. Trichlorethylene, carbon tetrachloride or other grease-solvents in liquid form are suitable cleaning agents; in addition, radio-active substances such as polonium may be used, which are brought into intimate sliding contact with the film.

When using liquid cleaning agents such as carbon tetrachloride, the film is drawn between two soft surfaces, such as velvet, saturated with the solution. The dissolving properties of the chemicals used, cause, along with the soft rubbing, the removal of foreign bodies adhering to the film.

The disadvantage inherent in cleaning with the aid of carbon tetrachloride and similar substances is that the film must be moistened with the chemicals and thoroughly dried after cleaning before being rewound. The use of dissolving liquids therefore takes up much time in addition to which great care must be exercised. The speed at which the film can be driven is limited. Although radio-active material such as polonium will remove the static charge of the film which causes dust, fibre particles or other impurities to adhere thereto it cannot eliminate finger prints, grease spots, oil or similar stains. Another disadvantage inherent in the use of polonium is that it emits alpha-rays, so that the greatest care must be exercised during treatment. Furthermore, radio-active cleaning takes up even more time than cleaning with carbon tetrachloride and similar substances, a fact which detrimentally affects the economic factor. It must be remembered, finally, that polonium will only prevent dust, fibre particles, and other foreign bodies from adhering to the film as a consequence of which small brushes or other devices, such as suction devices, must be used in addition for the removal of the foreign bodies.

It is therefore an object of the invention not only to eliminate the disadvantages referred to, but also to perform the working process with the aid of faster and at the same time simplified methods by subjecting the film conducted over rotating rollers, exclusively to kneading action with the elimination of friction or moistening, whereby the kneading elements are coated with an absorbing substance.

One of the most suitable absorbents is a dimethyl silicone oil mixed with boric acid and some alcohol to which, after exposure for approximately two hours to a temperature of 150 C., a filler in approximately double the quantity is added, whereupon the compound is subected to an approximately similar heat treatment. A compound suitable for the purposes of this invention may be prepared as follows:

Seventy-five parts by weight of a dimethyl silicone oil is thoroughly mixed with 10 parts of pyroboric acid in a small amount of alcohol and the resultant mixture heated in an oven for 2 hours at 150 degrees C. At the end of this time the mixture is in the form of a quasi-rubbery gel. Forty-five parts of the gel is mixed with parts lithopone and 0.9 part of benzoyl peroxide and worked on rubber compounding rolls until a uniform mass is obtained. An additional 45 parts dimethyl silicone oil and 0.9 part benzoyl peroxide is then added, worked into the mass, and the resultant product heated in an oven at a temperature of to degrees C. for 2 hours. The final product can be worked between the fingers in the same manner as ordinary window putty, and the more it is worked the more putty-like it becomes. The product also exhibits a high degree of elasticity or bounce.

The plastic and elastic properties may be enhanced by using boric acid esters. A compound prepared in the following manner is suitable:

A mixture of 200 parts of dimethyl silicone oil, 22.5 ethyl borate and 2.3 parts ferric chloride hexahydrate is placed in a suitable container and steam introduced into the mixture for one-half hour in order to hydrolyze the ester. The resultant product is placed in an oven and heated for 2 hours at 150 degrees C. after which it is worked with 10 percent by weight of finely-divided titanium oxide until the desired putty-like properties have been obtained. The characteristics of the composition described herein arise from a balance between the hydrophilic and hydrophobic groups, and the novel material which possesses both elastic and plasticproperties is probably a two-phase system comprising a highly cross-linked silicone network with hydrophobic methyl groups attached to the silicon. This assumption concerning the nature of the composition of the material proposed to be used according to the invention is strengthened by the unusual properties thereof. t

The friction between hydrophilic and hydrophobic groups is known to be high. As a result of the friction between these groups when the materials used for the purpose of this invention are subjected to a sudden but not sharp blow, as when dropped on a hard surface, the opposing groups are, for all practical purposes, locked so that the material responds as an elastic solid and exhibits a high degree of bounce. Under sharper impacts, as when struck with a hammer, the material behaves even more like a solid and breaks under such an impact with conchoidal fraction. n the other hand, when it is subjected to gradual pressure, as when worked between the fingers, the internal friction can be overcome so that the material is caused to exhibit its characteristic cold-flowing or puttylike properties. Additional hydrophilic and hydrophobic materials may also be added. For example, a little glycerine, soapy water, a hydroxide such as zinc hydroxide or a filler such as bentonite which contains absorbed water can be worked into the material to be used for the present invention in order to reach less elasticity but higher bounce characteristics. On the other hand, if oleic acid is added in amounts less than one percent, the material becomes quite soft, sometimes sticky and the bounce is reduced as the amount of oleic acid is increased. By judicious additions of alternate doses of oleic acid and glycerine, for example, one can modify the properties of the material in either direction.

As already set forth, the substance used in this invention has a number of uncommon physical properties. Among others, it has a very low elastic limit, so that it will become entirely plastic when distended slowly and will turn into a fluid if allowed to stand for a while, while it becomes brittle when distended rapidly. It will nevertheless remain highly elastic and rebound like a rubber ball. Its specific gravity is around 1.1 at a temperature of 20 C.

and it will dissolve in polar organic solutions. It will swell in carbon tetrachloride and a great number of aromatic hydrocarbons. It will not corrode metals.

The silicones employed in this invention offer important advantages in the cleaning of films as proved by practical tests as well as on the basis of comparisons with other cleaning agents.

When carbon tetrachloride is used as a cleaning agent, it will take from 80 to 120 minutes to clean a 2000' reel of 16 mm. film, while cleaning with polonium will require from 130 to 150 minutes. But when cleaning is carried out with the aid of this invention only to minutes will be necessary to clean the same length of film.

The accompanying drawings show one example of how the invention functions but it will be understood that many variations may be made.

In the accompanying drawings:

Fig. 1 is an elevation of the device in operation;

Fig. 2 is a view of a part of Fig. 1, while the film is being inserted;

Fig. 3 is a view similar to that of Fig. 2 after the cleaning rollers embracing the film have begun to pivot;

Fig. 4 is a view to an enlarged scale of a portion of Fig. 1;

Fig. 5 is a section taken on the line V-V of Fig. 4;

Fig. 6 is a cross-section through a film-cleaning roller;

Fig. 7 is a cross-section through a further form of filmcleaning roller with a protective sleeve;

Fig. 8 is a partial elevation corresponding to Fig. 4 of a further form of construction and,

Fig. 9 is a section taken on the line IX-IX of Figure 8.

As shown in Fig. l the film for cleaning passes from wind-off reel 2 to take-up reel 3 after passage through the cleaning arrangement. The parts shown in the drawing may be altered as required.

The film 1 running over two rollers 4 and 5 forms an S-shaped loop which ensures the closest contact possible of both sides of the film with the surface of the rollers. The said rollers 4 and 5 are coated with silicone as already described.

The said rollers 4 and 5 are mounted on a revolving plate or disc 6 in such a manner that either one or both of them have some freedom of transversal movement, so that the film will not break if its speed of travel between the wind-off and take-up reels 2 and 3 is changed suddenly. This is an important point owing to the fact that with the aid of this invention the film will be cleaned faster than has been possible hitherto. Should a high speed not be desired, such as in cases where cleaning is effected with the aid of the present device and method in combination with an examination of the film, the said rollers 4 and 5 may be mounted directly on revolving plate 6 without any freedom of transversal motion.

The said revolving plate 6 is mounted on a base or support member 7 provided with comparatively large-headed cap screws 8 and 9 by means of which the said revolving plate 6 may be locked or released for turning.

The base 7 is provided with two extension flanges 10 and 11, on which guide-roller pairs 12, 13 and 14, 15 are mounted, and to which may be fastened at the same time supports 16 and 17 by means of screws or similar fasteners 18. The said supports 16 and 17 are aflixed to a base plate 20 by means of screws 21 and 22, which base plate may advantageously form a support for a standard device for winding up films. In addition, brackets 23 and 24 for reels 2 and 3 are mounted on the said base plate 20.

Should the film 1 have a thick coating of dust or fibre particles, an additional cleaning device, such as a radioactive one, may be used to advantage. To that end polonium applicators 27 and 28 may be arranged on both sides of film 1 on base 7 or the flange 10. These additional installations do not affect the essential points of the invention and are to be considered only as supplementary.

Before inserting the film 1 into the cleaning device, the revolving plate 6 is turned counter-clockwise into the position shown in Fig. 2, so that the roller 4 comes to rest directly under roller 5. In this position the film will run between guide rollers 12 and 13, cleaning rollers 4 and 5 and guide rollers 14 and 15. Thereupon the said revolving plate 6 is moved clockwise past the intermediate position as shown in Fig. 3 until the final cleaning position shown in Fig. 1 has been reached. The heads of screws 25 and 26 that hold rollers 4 and 5 may be sufliciently large so that revolving plate 6 may be easily turned with the fingers by means of the said screw heads.

Figs. 6 and 7 show two different designs for the said rollers 4 and 5. The said rollers should be provided with a groove 29 which is to contain the silicone cleaning compound 30 according to this invention. The bore 31 of the roller core 32 receives bearing and fulcrum pin 33 which is screwed into bearing arm 34 or 35 as the case may be, which arm inturn is swivelled to revolving plate 6 by means of screw 36 or 37. The screws 25 or 26 as the case may be maintain the rollers 4 and 5 on bearing pin 33.

It must be remembered that the cleaning compound 30 would flow oif rollers 4 or 5 when the device is not in operation. It is therefore advisable to place a strip of paper, foil, or other similar material over the rollers 4 and 5 when the device is not running, so as to retain the cleaning substance 34) in position. It is best to store the device in a cool place when not in use.

As shown in Fig. 7 it is also advantageous to push sleeves 38 over rollers 4 and 5, the said sleeves being easily removable with the aid of collar 39. In that case the forward guide flange of rollers 4 and 5 does not corbel out above the cleaning preparation 30. The film 1 is guided laterally to a suflicient extent by guide rollers 12 to 15.

Owing to its consistency, the cleaning compound 30 may be applied easily to rollers 4 and 5. It will be superfluous to knead in the substance carefully since it will be distributed evenly over the rollers 4 and 5 within groove 29 after a few turns.

As shown in Figs. 4 and 5, the rollers are mounted in an easily pivotable manner on revolving plate 6 by means of pivot arms 34 and 35 and bearing screws 36 and 37. The pivot arms 34 and 35 strike stops 40 and 41 mounted on the said revolving plate 6, the said stops preventing further clockwise pivoting. Small springs 42 and 43 affixed to pins 44 and 4S draw the levers 34 and 35 outward counterclockwise, whereby the rollers 4 and 5 in conjunction with stops 40 and 41 are maintained in the position shown in Figs. 1 and 4. However, the labile bedding has the advantage of enabling the lever 34 to move clockwise when the film 1 is pulled too tight between wind-oflf reel 2 and roller 4, thus preventing the film from breaking.

In many cases it is possible, if desired, to provide only one pivotal roller, as shown in Figs. 8 and 9. Only the roller 5 is here shown as mounted on the pivot arm 35, whilst the roller 4 is mounted rotatably directly on the revolving plate 6.

Instead of cap screws 8 and 9 that hold the revolving plate 6 fast to the base 7, any other retaining means serving the same purpose, such as resilient clamp, may be used. According to Figs. 8 and 9, only one central clamping screw 46 is utilised, and an opening 47 in the swinging arm 35 is provided in order to make possible actuation of the screw 46.

The drive of the film take-up spool 3 may be eifected by hand by means of the crank 48 (as in Fig. 1) or by means of a motor.

Owing to the remarkably efficient cleansing eifect of compound 30, the film may be wound oflE at high speed, namely at the rate of from 100'-400' per minute. The silicone coatings will swallow up practically all the dirt or dust from both sides of film 1. No friction what soever occurs between the surfaces of the film and the cleaning compound so that the film will never be damaged in the slightest degree. Cleaning rather takes place through a continuous change in form, comparable to kneading of the compound 30. In spite of the very short contact between all the smallest parts of the film surfaces and the coating a thorough cleaning action consequently takes place, which may be supplemented or enhanced as desired by a preceding or subsequent treatment with known cleaning processes. will be superfluous.

But normally this measure Although particular reference has been' made inthe foregoing description to film and particularly photo graphic film, the invention has a wider scope. With the aid of this invention any surface of Celluloid or cellulose acetate as well as any other substance having a smooth surface, such as steel tape, wire, string, glass plates, etc., may be cleaned as described herein.

Apart from the remarkable cleaning action of the compound 30, mention must be made of the additipnal 6 and considerable advantage of the said compound being easily changeable and obtainable at low cost; furthermore, the same coating may be used for a surprisingly long period.

I claim:

1. A device for cleaning smooth-surfaced articles, comprising at least one rotatably arranged roller, means for guiding an article to be cleaned over said roller in intimate contact therewith, and an absorbent coating on said roller, said coating undergoing, during guiding of said article over the roller, a change of state similar to that caused by a kneading action, whereby said article is subjected only to a manipulation by said roller without the use of friction or moisture, said roller being formed with a circumferential channel for the reception of said coating, and means in said device for covering said absorbent coating on said roller when not in use, adapted to retain the coating in said channel.

2. A device as set forth in claim 1, wherein said retaining means for the roller in the channel is a removable sleeve.

3. A device as set forth in claim 1 wherein the width of the channel is commensurate with that of the article to be cleaned.

4. A device for cleaning smooth surfaced articles, comprising a support member, a vertically disposed revolving plate arranged within said support member, at least one pivotal arm mounted on said revolving plate, a cleaning roller carried rotatably on said arm, said roller being formed with a circumferential channel, means for guiding an article to be cleaned over said channel, a coating in said channel of a material which undergoes a change of state similar to that caused by a kneading action when said article is passed thereover, lateral guide rollers disposed on the support member on either side of the revolving plate, means for biasing said arm towards the periphery of said plate, and means for clamping said plate in a fixed position relative to the support member, whereby during insertion of the article into the device the revolving plate is turned to move the cleaning roller away from the path of said article between said guide rollers, and is then turned and clamped relative to said support member in a position effecting intimate contact of said cleaning roller with said article, the pivotal arm biasing means serving to maintain said pivotal contact.

5. A device for cleaning photographic film, comprising a mounting plate, a support member carried by said mounting plate, a vertically disposed revolving plate arranged within said support member, a pair of pivotal arms arranged in spaced relationship on the revolving plate, a cleaning roller carried rotatably on each arm, said rollers each being formed with a circumferential channel, a coating of silicon putty in each channel, lateral guide rollers disposed on the support member on either side of the revolving plate, means for biasing said arms towards the periphery of said plate, and means for clamping said plate in a fixed position relative to said support member, whereby on insertion of the film into the device the revolving plate is turned to cause the cleaning rollers to lie perpendicularly one above the other, so that said film extends between said rollers and between the lateral guiding rollers, when the revolving plate is turned and clamped relative to the support member to cause the film to become wound around-said cleaning rollers in an S-sl1aped loop in intimate-Yeoman with said putty, said pivotal arm biasing means serying to maintain said intimate contact.

6. A deviceas set forth in claim 5 wherein the revolving plate carries-stops limiting the pivotal movement of the pivot arms. and said biasing means comprise tension springsurging said arms against said stops whilst permittinga pendular play of said arms in the event of excessive film tension.

7. A device for cleaning photographic film, comprising a mounting plate, a support member carried by said mountin'gplate, a vertically disposed revolving plate ari 7 ranged within said support member, a pivotal arm'arranged on the revolving plate, a first cleaning roller arranged rotatably on said pivotal arm, a second cleaning roller rotatably mounted directly on said revolving plate, said rollers each being formed with a circumferential channel, a coating of silicon putty in each channel, lateral guide rollers disposed on the support member on either side of the revolving plate, means for biasing said arm towards the periphery of said plate, and means for clamping said plate in a fixed position relative to said support member, whereby on insertion of the film into the device the revolving plate is turned to cause the cleaning rollers to lie perpendicularly one above the other, so that said film extends between said rollers and between the lateral guiding rollers, when the revolving plate is turned and clamped relative to the support member to cause the film to become wound around said cleaning rollers in an S-shaped loop in intimate contact with said putty, said pivotal arm biasing means serving to maintain said intimate contact.

References Cited in the tile of this patent UNITED STATES PATENTS 1,189,633 Shue July 4, 1916 2,256,744 Lincoln Sept. 23, 1941 2,541,851 Wright Feb. 13, 1951

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