US2098367A - Moving picture film printing machine - Google Patents

Moving picture film printing machine Download PDF

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US2098367A
US2098367A US542867A US54286731A US2098367A US 2098367 A US2098367 A US 2098367A US 542867 A US542867 A US 542867A US 54286731 A US54286731 A US 54286731A US 2098367 A US2098367 A US 2098367A
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film
negative
positive
sprocket
drum
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US542867A
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Remsen V Wood
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RCA Corp
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RCA Corp
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    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03BAPPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00Photographic printing apparatus
    • G03B27/02Exposure apparatus for contact printing
    • G03B27/04Copying apparatus without a relative movement between the original and the light source during exposure, e.g. printing frame or printing box
    • G03B27/08Copying apparatus without a relative movement between the original and the light source during exposure, e.g. printing frame or printing box for automatic copying of several originals one after the other, e.g. for copying cinematograph film

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  • This invention relates to moving picture printing machines and more specifically to the type known as continuous motion printing apparatus used forprinting the sound record of the film and the object of this invention is to provide an apparatus in which the negative and posit1ve film are brought together at the point where the printing operation takes place while new and improved driving means operate to cause both the negative and positive film to be driven at the same constant speed so that no slippage occurs between them at this printing point.
  • Another object of this invention is to provide driving means for the negative film which automatically compensate for the difference in the length of the positive film and the negative film due to the shrinkage in one or both of the films.
  • Another object of this invention is to provide guiding means in combination with a control drum so that the positive film may be held in frictional contact with the periphery of the drum and in alignment with the guide flanges thereof.
  • Another object of this invention is to provide lateral guiding means for the negative film with which the negative film is brought in alignment with the positive film and the guide flanges of the control drum at the point where the printing operation takes place.
  • FIG. 4 is a vertical sectional view of the portion of the apparatus illustrated in Figure 3, the section being taken on the line 4a:-4:c of Fi ure 3.
  • Figure 5 is a detail sectional view of the rubber mounting of one of the guide rollers, the section being taken on the line 5.'c-5:r of Figure 4.
  • Figure 6 is a horizontal sectional view of the a modified Figure 10 is a vertical sectional view of the.
  • the motion picture film printing apparatus forming the subject matter of my present invention operates to photographically print the sound record of a negative film onto the positive copy thereof so that the combined sound and picture records on the positive film will have the same relation to each other as the corresponding records on the negative film.
  • There is usually a slight difference between the length of the negative film and that of the positive film which may be due to a shrinkage of the negative film in the development of it or may be due to a shrinkage in the positive film due to its age and this inequality in the length of the two films must therefore be compensated for before the negative sound record is photographically transferred onto the positive film. This is accomplished in a novel and improved manner in my present apparatus as will hereinafter be described.
  • the apparatus comprises an upright frame I which is supported on a suitable base 2. On the upright are provided the studs 3 and 4 on which are mounted to rotate the negative film roll 5 and the positive film roll 6 respectively.
  • the spring fingers I and 8 overhang the two film rolls in order to keep them from sliding off the studs during the unwinding of the films.
  • Mounted to rotate in the upright frame I at points opposite to the studs 3 and 4 are a pair of shafts 9 and III. These shafts are adapted to have the hubs or reels 38 and 35 removably keyed or splined thereto so that on the rotation of the shafts the negative and the positive film may be Wound up thereon.
  • the shafts 9 and I0 carry the pulleys I I and I2 respectively which are driven by suitable belts I3 and I4 from a pulley I5 mounted on the shaft I6.
  • the shaft I 6 also carries the pulley I1 which is driven by the belt I8 from the pulley IQ of the motor 20.
  • and 22 overhang the negative and positive films as they are wound onto the hubs or reels in order to guide the films and keep the hubs or reels from sliding off the shafts 1 and H).
  • the negative and positive films are unwound from their spools or reels mounted on the studs 3 and 4 so that their emulsion or coated side face each other when brought together and held in mesh with the film sprocket 23.
  • This sprocket is mounted on the shaft l6 driven by the'pulley I! from the motor and its teeth 24 simultaneously engage into the perforations 25 provided in the negative and positive films to positively feed the mesh with the film sprocket 23, a pair of flanged by the motor 2
  • contact rollers 26 and 21 engage the back of the positive. film to force it and the negative film against the film sprocket so that the teeth thereof engage the perforations in the film.
  • the idle contact rollers 26 and 21 are mounted on the swinging arm 28 which is pivoted to the upright frame I by means of the stud 29.
  • a spring latch 30 mounted on the upright frame to one side of the swinging arm 28 engages the swinging arm and normally holds it in the position in which the rollers 26 and 2! keep the films in mesh with the sprocket.
  • the rollers When bringing the two films together and threading them onto the film sprocket the rollers are released from the film sprocket by depressing the spring latch 30 so that the swing- .ing arm can swing to the right and move the rollers away from the film sprocket. The matched films can then be brought into contact and mesh with the film sprocket so that after the rollers are swung back they keep the films in contact and mesh with the film sprocket.
  • the two films are held in contact with the film sprocket over a considerable length of the perimeter of the sprocket in order to give the sprocket a good hold on the films.
  • the sprocket is driven This motor has a constant speed so that the negative and positive film are fed in unison at relatively constant speeds from their respective rolls over the film sprocket 23.
  • the positive film travels over the yieldingly mounted guide roller 3
  • the negative film after leaving the film sprocket, continues on to a point on top of the governing drum 32 where it is held in contact with the positive film by means of the pressure roller 36.
  • the negative film then passes on to a .-point to one side of the drum where it is reversed that both the negative and positive film are positively unwound at relatively uniform speeds from their respective rolls during the first part of their movement before the printing operation takes place and are later on wound up again at relatively uniform speeds after the printing operation hastaken place.
  • the films are wound up on suitable hubs or reels after It is during the movement of the films from the film sprocket over the control drum and back to the film sprocket that the difference in length of the two films, due to the shrinkage in the negative film and positive film, is compensated for.
  • the positive film is separated from the negative film as soon as it leaves the film sprocket and is made to travel over the yieldingly mounted guide roller 3
  • the control drum 32 has a comparatively large diameter and is mounted to freely rotate on the stud 40 and is driven by the frictional contact with the positive film as it travels over it from the yieldingly mounted roller 3
  • the momentum of the control drum when in motion serves to take up any irregularity in the movement of the positive film after it leaves the film sprocket by exerting a constant pull on the film.
  • the film in its travel over the control drum, is thus held tightly in frictional contact with the periphery of the drum by the yielding force of the mountings of the guide rollers 3
  • This frictional contact causes the drum to rotate with the film while its momentum serves to steady its movement.
  • the momentum of the drum keeps on feeding the film over its periphery at the original constant speed. This is possible because in such an event the pull on the film exerted by the momentum of the drum will raise the guide roller 3
  • and 33 have the flanges 45 and 46, one at each end, which serve to guide the film against the inside of the guide flanges 41 and 48 of the control drum 32.
  • Th negative film passes directly from the film sprocket 23 to the top of the control drum between the guide flanges 41 and 48 thereof and is held in contact with the positive film by means of the pressure roller 36.
  • This roller has an annular ridge 49 around its circumference at one end of the roller so that only this ridge makes contact with the film as it travels under the roller. This is for a purpose that will presently appear.
  • the roller is mounted to rotate on a stud 50 which is anchored near the outer end of the swinging arm 5
  • the light chamber 53 On the outer end of the swinging arm 5
  • This light chamber has the light tube 54 projecting from the bottom thereof and in this light tube is mounted the lens 55 which focuses the filament of the incandescent light 56 located in the light chamber onto the sound record of the negative film to photographically print this record onto the positive film located underneath it.
  • the light tube 54 is located alongside the end of the pressure roller 36 so that the annular ridge 49 thereof holds the negative film firmly in contact with the positive film at a point in close proximity to the printing point.
  • the incandescent light for printing the negative sound record onto the positive film is mounted in a socket 51 which is adapted to slide up and downwithin the light chamber so that it can be vertically adjusted to bring the filament of the light in focus with the lens 55 in the light tube.
  • a set screw 58 passes thru the wall of the light chamber to engage the socket of the incandescent light and hold it in place in the adjusted position.
  • the pressure roller 36 is held in contact with the film by its own weight, the weight of the arm on which it is mounted, and the weight of the light chamber carried by this arm above the pressure roller. The pressure exerted by the roller on the negative film firmly holds this film in contact with the positive film located.
  • both the positive and negative film will have a uniform and con-- stant movement at the point of contact between them.
  • the diameter of the control drum is comparatively large and this is not only for the purpose above described but also in order to produce as little stretch in the coated side of the positive film as it travels over it. This is to keep the positive film as much as possible in its original form. The little stretch which the curvature in the positive film produces as it travels over the drum is suificient to compensate for any shrinkage which may have taken place due to the age of the film.
  • the negative film is usually shorter than the positive film because of the shrinkage during processing and due to this and the fact that the perforations of the two films are matched by the teeth of the film sprocket, the speed of the negative film is slightly slower than the speed of the positive film by the per cent of the shrinkage which may be about one-half of one per cent.
  • the linear speed of the two films is therefore different at their pitch diameters by this same percentage.
  • the emulsion surface of the shrunken negative is longer than its pitch diameter due to its radius of curvature which has caused it to stretch.
  • the positive is also curved to make its emulsion surface longer than its pitch diameter, but as the radius of this curvature is large, the difference is less. If therefore the radius of curvature of the loop of the negative film is small, the emulsion surface of this film is stretched more than the emulsion surface of the positive film and as their outer surface speeds are the same at their point of contact, the negative film will fall behind the positive film until the loop in the negative film becomes the proper size .to compensate for the degree of shrinkage in the negative film. The reverse occurs when the radius of the curvature of the loop in the negative is large, in which case the loop automatically adjusts itself within the limits of the radius of the pressure roller and the control drum according to the shrinkage in the negative film.
  • the negative and positive films travel together over the control drum for a short distance after the printing operation has taken place until the movement of the negative film is reversed in a loop 60 so as to pass under the guide roller 37.
  • This guide roller is mounted so as to slightly crowd the inner edge of the film against the inner guide flange of the control drum. This action of the guide roller tends to turn the negative film under the point of contact of the pressure roller with the negative film so that the front edge of the negative film is crowded against the outer guide flange of the control drum at the printing point to insure a perfect alignment of the outer edge of the negative film with the outer edge of the positive film during theprinting operation.
  • FIG 7 I have shown a diagrammatic view of a modified form of the driving means for feeding the positive film at a constant speed over a control drum.
  • the guide rollers MA and 33A the mounted on a rubber base A which is mounted to swing laterally on the frame of the apparatus by means of a pair of arms Hit! and NH.
  • the elastic base A in turn is connected to a second elastic base MB which is anchored to the frame of the apparatus near each end thereof.
  • FIG 8 I have shown a diagrammatic view of another modified form of the driving means for the positive film.
  • two pair of yieldingly mounted guide rollers MB and 33B are used and are mounted on the elastic rubber base MC.
  • both of these modified driving means is similar to that illustrated in Figures 1 to 4 inclusive in that the yieldingly mounted rollers are adapted to move bodily to compensate for any irregularity in the movement of the film due to an irregular movement of the film.
  • control drum M02 is provided with an annular channel 103 in the periphery thereof. This channel is located on the drum directly below the sound record on the film so that the light from the light tube I04 in passing thru the negative film and positive film falls onto the end of the quartz rod I05. This rodis suitably mounted outside of the drum so as to project into the annular channel.
  • the quartz rod tapers to a wedge with a-small plane surface formed at theend of the wedge having an outline equal in size and form to the scanning beam.
  • This beam of light which falls on the plane surface of the wedge shaped end of the rod is thus deflected thru the rod to one side of the drum to the light sensitive cell I06 and a suitable audio circuit (not shown) is connected to the light sensitive cell to translate the beam of light which has been projected thru the films into audible sounds.
  • a too loud or harsh a sound produced by the sound record on the negative film may be readily detected during the printing operation and modified on the positive film by regulating the intensity of the light.
  • a film sprocket adapted to have a positive and negative film mesh simultaneously therewith, a control drum adapted to have the positive film travel over the periphery thereof, an annular guide fiange on said control drum, a pressure roller, an annular ridge on the periphery of said pressure roller, said negative film being adapted to travel under said pressure roller to have said annular ridge make contact with the negative film and force said negative film into frictional contact with the positive film while traveling over said control drum, means for guiding the positive roller back into mesh with said film sprocket and a guide roller adapted to guide the negative film at a slight angle away from said pressure roller to slightly turn the film under the annular ridge of said pressure roller and force one edge of the negative film against said guide flange of said control drum into alignment with the corresponding edge of the positive film at the point of contact between the two films on said control drum.
  • a film sprocket adapted to feed the negative film and positive film simultaneously from their respective supply rolls
  • a con trol drum means for guiding the negative and positive film from the film sprocket to said control drum, said control drum having an annular channel in the periphery thereof, a source of light creating a light beam, means for projecting

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Description

Nov. 9, 1937.
R. v. WOOD MOVING PICTURE FILM PRINTING MACHINE 5 Sheeds-Sheet 1 Original Filed June 8, 1951 3.11 fie].
/A\' VITA TOR fie/155M M Map 1)) .4 T RNEY Nov. 9, 1937.
v. WOQD MOVING PICTURE FILM PRINTING MACHINE Original Filed June 8, 1931 5 Sheets-Sheet 2 x 3 w f x manna H H n 5 5 w 5 H II: a w a w w $5 ,5
fie. 3.
Rinse/v M Moon [NVENTOR R. V. WOOD MOVING PICTURE FILM PRINTING MACHINE Oiriginal Filed June 8, 1931 5 Sheets-Sheet 3 Nov. 9, 1937.
Nov. 9, 1937. R. v. WOOD 2,098,367
MOVING PICTURE FILM PRINTING MACHINE Original'Filed June 8, 1931 5 Sheets-Sheet 4 fies. v 56.7.
[NVENTOR [FE/15E KMQD ATT NEY Nov. 9, 1937. R. v. WOOD 2,098,367
MOVING PICTURE FILM PRINTING MACHINE I Original Filed June 8, 1931 5 Sheets-Sheet 5 l/VVENTOR mMSEN M May Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE MOVING PICTURE FILM PRINTING MACHINE ration of Delaware Application June 8, 1931, Serial No. 542,867 Renewed September 28, 1934 2 Claims.
This invention relates to moving picture printing machines and more specifically to the type known as continuous motion printing apparatus used forprinting the sound record of the film and the object of this invention is to provide an apparatus in which the negative and posit1ve film are brought together at the point where the printing operation takes place while new and improved driving means operate to cause both the negative and positive film to be driven at the same constant speed so that no slippage occurs between them at this printing point.
Another object of this invention is to provide driving means for the negative film which automatically compensate for the difference in the length of the positive film and the negative film due to the shrinkage in one or both of the films.
Another object of this invention is to provide guiding means in combination with a control drum so that the positive film may be held in frictional contact with the periphery of the drum and in alignment with the guide flanges thereof.
Another object of this invention is to provide lateral guiding means for the negative film with which the negative film is brought in alignment with the positive film and the guide flanges of the control drum at the point where the printing operation takes place.
Another object of this invention is to provide means whereby the sound record of the negative film may be translated into sound during the printing operation to permit the regulation of the intensity of the light used for printing to change the intensity of the sound that is printed Figure 4 is a vertical sectional view of the portion of the apparatus illustrated in Figure 3, the section being taken on the line 4a:-4:c of Fi ure 3.
Figure 5 is a detail sectional view of the rubber mounting of one of the guide rollers, the section being taken on the line 5.'c-5:r of Figure 4.
Figure 6 is a horizontal sectional view of the a modified Figure 10 is a vertical sectional view of the.
apparatus illustrated in Figure 9, the section being taken on the line I xIIIa: in Figure 9.
In the several figures of the drawings like reference numerals indicate like parts.
The motion picture film printing apparatus forming the subject matter of my present invention operates to photographically print the sound record of a negative film onto the positive copy thereof so that the combined sound and picture records on the positive film will have the same relation to each other as the corresponding records on the negative film. There is usually a slight difference between the length of the negative film and that of the positive film which may be due to a shrinkage of the negative film in the development of it or may be due to a shrinkage in the positive film due to its age and this inequality in the length of the two films must therefore be compensated for before the negative sound record is photographically transferred onto the positive film. This is accomplished in a novel and improved manner in my present apparatus as will hereinafter be described.
The apparatus comprises an upright frame I which is supported on a suitable base 2. On the upright are provided the studs 3 and 4 on which are mounted to rotate the negative film roll 5 and the positive film roll 6 respectively. The spring fingers I and 8 overhang the two film rolls in order to keep them from sliding off the studs during the unwinding of the films. Mounted to rotate in the upright frame I at points opposite to the studs 3 and 4 are a pair of shafts 9 and III. These shafts are adapted to have the hubs or reels 38 and 35 removably keyed or splined thereto so that on the rotation of the shafts the negative and the positive film may be Wound up thereon. For this purpose the shafts 9 and I0 carry the pulleys I I and I2 respectively which are driven by suitable belts I3 and I4 from a pulley I5 mounted on the shaft I6. The shaft I 6 also carries the pulley I1 which is driven by the belt I8 from the pulley IQ of the motor 20. In this way the negative and positive films the printing operation has taken place between them. Suitable spring fingers 2| and 22 overhang the negative and positive films as they are wound onto the hubs or reels in order to guide the films and keep the hubs or reels from sliding off the shafts 1 and H).
The negative and positive films are unwound from their spools or reels mounted on the studs 3 and 4 so that their emulsion or coated side face each other when brought together and held in mesh with the film sprocket 23. This sprocket is mounted on the shaft l6 driven by the'pulley I! from the motor and its teeth 24 simultaneously engage into the perforations 25 provided in the negative and positive films to positively feed the mesh with the film sprocket 23, a pair of flanged by the motor 2|].
contact rollers 26 and 21 engage the back of the positive. film to force it and the negative film against the film sprocket so that the teeth thereof engage the perforations in the film. The idle contact rollers 26 and 21 are mounted on the swinging arm 28 which is pivoted to the upright frame I by means of the stud 29. A spring latch 30 mounted on the upright frame to one side of the swinging arm 28 engages the swinging arm and normally holds it in the position in which the rollers 26 and 2! keep the films in mesh with the sprocket. When bringing the two films together and threading them onto the film sprocket the rollers are released from the film sprocket by depressing the spring latch 30 so that the swing- .ing arm can swing to the right and move the rollers away from the film sprocket. The matched films can then be brought into contact and mesh with the film sprocket so that after the rollers are swung back they keep the films in contact and mesh with the film sprocket.
As illustrated in Figure 1 the two films are held in contact with the film sprocket over a considerable length of the perimeter of the sprocket in order to give the sprocket a good hold on the films. As above described the sprocket is driven This motor has a constant speed so that the negative and positive film are fed in unison at relatively constant speeds from their respective rolls over the film sprocket 23. After leaving the film sprocket the positive film travels over the yieldingly mounted guide roller 3| onto the control drum 32 and from this drum over another yieldingly mounted guide roller 33 and the guide roller 34, again into mesh with the film sprocket 23 and from the film sprocket to the spool or reel 35 carried by'the shaft Ill where the positive film is wound up.
The negative film, after leaving the film sprocket, continues on to a point on top of the governing drum 32 where it is held in contact with the positive film by means of the pressure roller 36. The negative film then passes on to a .-point to one side of the drum where it is reversed that both the negative and positive film are positively unwound at relatively uniform speeds from their respective rolls during the first part of their movement before the printing operation takes place and are later on wound up again at relatively uniform speeds after the printing operation hastaken place.
are wound up on suitable hubs or reels after It is during the movement of the films from the film sprocket over the control drum and back to the film sprocket that the difference in length of the two films, due to the shrinkage in the negative film and positive film, is compensated for. For this purpose the positive film is separated from the negative film as soon as it leaves the film sprocket and is made to travel over the yieldingly mounted guide roller 3| where its movement is reversed so that the coated side of the film faces the outside of the drum as it travels over it to the yieldingly mounted roller 33 on the other side of the governing drum and back to the film sprocket 23.
The control drum 32 has a comparatively large diameter and is mounted to freely rotate on the stud 40 and is driven by the frictional contact with the positive film as it travels over it from the yieldingly mounted roller 3| to the yieldingly mounted roller 33. The momentum of the control drum when in motion serves to take up any irregularity in the movement of the positive film after it leaves the film sprocket by exerting a constant pull on the film. When the positive film is threaded into the printing apparatus from the film sprocket and back again over the yieldingly mounted guide rollers and the control drum located between them, the film is placed under a tension which is opposed by the yielding resistance of the mountings of the guide rollers 3| and 33 on each side of the control drum 32. The film, in its travel over the control drum, is thus held tightly in frictional contact with the periphery of the drum by the yielding force of the mountings of the guide rollers 3| and 33. This frictional contact causes the drum to rotate with the film while its momentum serves to steady its movement. Thus, if for any reason the movement of the film sprocket should momentarily slow up, the momentum of the drum keeps on feeding the film over its periphery at the original constant speed. This is possible because in such an event the pull on the film exerted by the momentum of the drum will raise the guide roller 3| and'allow the guide roller 33 to correspondingly lower itself in order to maintain the original linear speed of the film as it moves overthe drum from one guide roller to the other.
The reverse takes place on a slight increase in the movement of the fihn-sprocket. In such a case the momentum of the control drum will have a braking effect on the film so that the tension of the guide roller 3| on the film is slightly relieved which allows it to lower itself. The guide roller 33 on the. other hand is raised by the increased pull exerted by the increased speed of the film sprocket while the momentum of the control drum keeps the film section passing over it from one guide roller to the other at its original constant linear speed. Each of the rollers 3| and 33 is mounted on a pivot pin 4| which is carried near the outer end of an arm 42. This arm is pivoted on a stud 43 to permit a swinging motion thereof. Fastened to the frame I to one side of the rollers 3| and 33 is an elastic rubber pad 44. This elastic pad is attached to the frame at the top and bottom and has the pivot pin 4| anchored thereto in the middle thereof. The rubber pad thus yieldingly holds the pivot pin 4| and with it the roller carried by it, in posi ion. The yieldingly mounted rollers 3| and 33 have the flanges 45 and 46, one at each end, which serve to guide the film against the inside of the guide flanges 41 and 48 of the control drum 32.
Th negative film passes directly from the film sprocket 23 to the top of the control drum between the guide flanges 41 and 48 thereof and is held in contact with the positive film by means of the pressure roller 36. This roller has an annular ridge 49 around its circumference at one end of the roller so that only this ridge makes contact with the film as it travels under the roller. This is for a purpose that will presently appear. The roller is mounted to rotate on a stud 50 which is anchored near the outer end of the swinging arm 5|. This arm is pivoted on the stud 52 anchored in the frame I and on this stud is also mounted to rotate the guide roller 34.
On the outer end of the swinging arm 5| above the pressure roller 36 is mounted the light chamber 53. This light chamber has the light tube 54 projecting from the bottom thereof and in this light tube is mounted the lens 55 which focuses the filament of the incandescent light 56 located in the light chamber onto the sound record of the negative film to photographically print this record onto the positive film located underneath it. The light tube 54 is located alongside the end of the pressure roller 36 so that the annular ridge 49 thereof holds the negative film firmly in contact with the positive film at a point in close proximity to the printing point. The incandescent light for printing the negative sound record onto the positive film is mounted in a socket 51 which is adapted to slide up and downwithin the light chamber so that it can be vertically adjusted to bring the filament of the light in focus with the lens 55 in the light tube. A set screw 58 passes thru the wall of the light chamber to engage the socket of the incandescent light and hold it in place in the adjusted position. The pressure roller 36 is held in contact with the film by its own weight, the weight of the arm on which it is mounted, and the weight of the light chamber carried by this arm above the pressure roller. The pressure exerted by the roller on the negative film firmly holds this film in contact with the positive film located. underneath so that the motion of the positive film is transmitted to the negative film at this point of contact between the pressure roller and the negative film and between the negative film and the positive film. In this way both the positive and negative film will have a uniform and con-- stant movement at the point of contact between them.
As previously pointed out the diameter of the control drum is comparatively large and this is not only for the purpose above described but also in order to produce as little stretch in the coated side of the positive film as it travels over it. This is to keep the positive film as much as possible in its original form. The little stretch which the curvature in the positive film produces as it travels over the drum is suificient to compensate for any shrinkage which may have taken place due to the age of the film. 1
The negative film is usually shorter than the positive film because of the shrinkage during processing and due to this and the fact that the perforations of the two films are matched by the teeth of the film sprocket, the speed of the negative film is slightly slower than the speed of the positive film by the per cent of the shrinkage which may be about one-half of one per cent. At the printing point where the films aredriven by the frictional contact with each other the linear speed of the two films is therefore different at their pitch diameters by this same percentage. However the emulsion surface of the shrunken negative is longer than its pitch diameter due to its radius of curvature which has caused it to stretch. To be sure the positive is also curved to make its emulsion surface longer than its pitch diameter, but as the radius of this curvature is large, the difference is less. If therefore the radius of curvature of the loop of the negative film is small, the emulsion surface of this film is stretched more than the emulsion surface of the positive film and as their outer surface speeds are the same at their point of contact, the negative film will fall behind the positive film until the loop in the negative film becomes the proper size .to compensate for the degree of shrinkage in the negative film. The reverse occurs when the radius of the curvature of the loop in the negative is large, in which case the loop automatically adjusts itself within the limits of the radius of the pressure roller and the control drum according to the shrinkage in the negative film.
The negative and positive films travel together over the control drum for a short distance after the printing operation has taken place until the movement of the negative film is reversed in a loop 60 so as to pass under the guide roller 37. This guide roller is mounted so as to slightly crowd the inner edge of the film against the inner guide flange of the control drum. This action of the guide roller tends to turn the negative film under the point of contact of the pressure roller with the negative film so that the front edge of the negative film is crowded against the outer guide flange of the control drum at the printing point to insure a perfect alignment of the outer edge of the negative film with the outer edge of the positive film during theprinting operation. While I have shown and described the negative film as being in contact with the positive film during a short distance over the control drum, this is not necessary because the negative film need only make contact with the positive film at the printing point or contact with the films and the films in mesh with the film sprocket.
In Figure 7, I have shown a diagrammatic view of a modified form of the driving means for feeding the positive film at a constant speed over a control drum. In this modification the guide rollers MA and 33A the mounted on a rubber base A which is mounted to swing laterally on the frame of the apparatus by means of a pair of arms Hit! and NH. The elastic base A in turn is connected to a second elastic base MB which is anchored to the frame of the apparatus near each end thereof.
In Figure 8, I have shown a diagrammatic view of another modified form of the driving means for the positive film. In this form two pair of yieldingly mounted guide rollers MB and 33B are used and are mounted on the elastic rubber base MC.
The action of both of these modified driving means is similar to that illustrated in Figures 1 to 4 inclusive in that the yieldingly mounted rollers are adapted to move bodily to compensate for any irregularity in the movement of the film due to an irregular movement of the film.
sprocket as described in connection with Figures 1 to 4 inclusive.
In Figures 9 and 10 I have illustrated means whereby the sound record of the negative film may be translated into sound while the printing operation between the negative film and the positive film takes place. For this purpose the control drum M02 is provided with an annular channel 103 in the periphery thereof. This channel is located on the drum directly below the sound record on the film so that the light from the light tube I04 in passing thru the negative film and positive film falls onto the end of the quartz rod I05. This rodis suitably mounted outside of the drum so as to project into the annular channel.
At the point below the positive film the quartz rod tapers to a wedge with a-small plane surface formed at theend of the wedge having an outline equal in size and form to the scanning beam. This beam of light which falls on the plane surface of the wedge shaped end of the rod is thus deflected thru the rod to one side of the drum to the light sensitive cell I06 and a suitable audio circuit (not shown) is connected to the light sensitive cell to translate the beam of light which has been projected thru the films into audible sounds. In this way a too loud or harsh a sound produced by the sound record on the negative film may be readily detected during the printing operation and modified on the positive film by regulating the intensity of the light.
Of course the moving picture film printing apparatus, shown and described, may be changed in various ways, and variations may be required under certain conditions, therefore, while some constructional details are deemed preferable and I have shown and described these specifically, it is to be understood that I do not limit myself to such precise construction, but consider that I am at liberty to make such changes and alterations as fairly come within the scope of the appended claims. 1
I claim:
1. In a moving picture printing machine the combination of a film sprocket adapted to have a positive and negative film mesh simultaneously therewith, a control drum adapted to have the positive film travel over the periphery thereof, an annular guide fiange on said control drum, a pressure roller, an annular ridge on the periphery of said pressure roller, said negative film being adapted to travel under said pressure roller to have said annular ridge make contact with the negative film and force said negative film into frictional contact with the positive film while traveling over said control drum, means for guiding the positive roller back into mesh with said film sprocket and a guide roller adapted to guide the negative film at a slight angle away from said pressure roller to slightly turn the film under the annular ridge of said pressure roller and force one edge of the negative film against said guide flange of said control drum into alignment with the corresponding edge of the positive film at the point of contact between the two films on said control drum.
2. In a moving picture printing machine the combination of a film sprocket adapted to feed the negative film and positive film simultaneously from their respective supply rolls, a con trol drum, means for guiding the negative and positive film from the film sprocket to said control drum, said control drum having an annular channel in the periphery thereof, a source of light creating a light beam, means for projecting
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525522A (en) * 1948-12-15 1950-10-10 Eastman Kodak Co Triple head rotary registry printer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525522A (en) * 1948-12-15 1950-10-10 Eastman Kodak Co Triple head rotary registry printer

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