US1826858A

US1826858A - Photographic printing apparatus

Info

Publication number: US1826858A
Application number: US242346A
Authority: US
Inventors: Vladimir K Zworykin
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1927-12-24
Filing date: 1927-12-24
Publication date: 1931-10-13
Anticipated expiration: 1948-10-13

Description

v, K. ZWORYKIN 1,826,858

PHOTOGRAPHIC PRINTING APPARATUS Oct.13 1931.

Filed Dec. 24, 1927 4 INVENTOR Patented Oct. 13, 1931 {UNITE STATES PATENT O F- vnanmm x. zwonrim, or swrssvann, rmsnvmm assxenoa 'ro wm'rmonousn Jamaica nmuorumo 'coan'm. a ooaroaarror or rmsnyams MG APPARATUS a uuuon am December :4. Serial lama.

1' My invention relates to photographic I printing apparatus, and it has particular reither an enlargement or reduction in dimensions.

lation to apparatus for use in printinglone moving-picture film from another, with Machines of many different tmlbave been proposed for use in the continuous printing of movin -picture film "-fro'ma ne ative, a edited, and ranged in Substantial y every machine of the character ositiv'es r the latteras n redetermined sequential order.

'just mentioned comprises a plurality of rotary film magazines, certain ofwhich' acco m-' modate' the negative'film and others of which carry the positive film before and after exposure.

' In order that the tive and negative films shall travel throug tl fe machine at the prop 1 er relative speeds, it has been customary, in

the past, to interconnect the positive and negative-film magazines by suitable gearing for transmitting motion thereb'etween;

Film-printing machines of the type in which gears are utilized to transmit motion ,4 between the several moving parts thereof have sentin venfa fair degree of satisfaction in the repr notion of moving-picture films of the usual type, but, in generahfail to satisfactorily reproduce films of the type wherein the pictures are accompanied by a marginal portion re resentative of sounds that were pho-- tograp ically'recorded on thenegative.

The variation in the. relative rates of positive and negative film travel through printing-machines, caused by the back-lash in the gear-trains, or by the slippage if belt connections are used. although msufiicient to prevent the roper printing of the picture-portions of t e film, is still enough to seriously interfere with the reproduction of the extremely minute film-density variations represound. If the film'is to be reduced in wi th and lengthin the printing operation, the utmost fidelity in reproduction is imperative, a fact which has heretofore prevented the satisfactory reduction-in size of "commercial talking-picture films for use. in

projectors of the home type.

the various portions thereof ar-- ture films trains are not 'reli It is, accordingly, an object of my invention to provide 'an apparatus for the general pirpose of film printing, the said apparatus mg adapted to either enlarge or re tion-picture films with absolute fidelity. 7

Another object of my invention is to provide film' prlnting apparatus wherein variation between the rate of travel of the positive :pdetyhe negative film is prevented with cerm Another object of my invention is to provide. filmrinting apparatus especially adapted for t e. reproduction of motion-picof the type which carry a sound record in addition to the icture record.

' Another object of my invention is to provide a film-printing machine particularly graphic sound records.

- Another 'ect of my invention is to provide affilm-prm. machine in,.which rdevices, a plurality of toothed wheels mount ed in spaced relation on, a rotatable shaft. Two of the wheels are of large diameter and upon to transmit motion .adapted for the reproduction of phototwo are of smaller diameter, the latter pair being-ailixed to the shaft intermediate the large wheels.v The largefilm is fed from a magazine over the pair of large wheels, while the small film is fed over the small wheels in pligferably mags):

a similar manner. The shaft is rotated by a small motor, and the zinesare geared thereto.-

A source of light and a lens system are so disposed that H ht may be transmitted through the negative film to fall upon the unexposed sensitive surface of the positive'film. The light source, when a reduction in, film size is to be made,- is positioned e'xteriorly of the large wheels over which the negative film is fed, and the light therefrom, passing through the negative film, falls upon the surface of the unexposed film carried over the smaller wheels. If the device is to be used for enlarging, the negative filmis fed across the small wheels and the positive film across the large wheels, the light source being so repositioned that the negative film passes between it and the positive film. V

In order to avoid confusion, I have chosen the term negative as. characterizing any film which has been exposed and,de veloped,

irrespective of Whether the film is of the so-' taken in connection with the accompanying I drawings, in which:

Figure 1 is a front elevational view of a portion of a film-printing machine comprisingva preferred embodiment of my invention. ig. 2 is a sectional view, taken along a line corresponding to the line IIII of Fig. 1.

Fig. 3 is a plan view of the guide elements over which the film passes.

Fig. 4 is a sectional view, taken 'along a line corresponding to the line IVIV of ig. 5 is a diagrammatic view, partly in section, of a modified form of my invention. Fig. 6 is a view, in perspective, of a portion of the optical system comprised in the apparatus illustrated in Fig. 5.

The apparatus shown in Figs. 1 and 2 comprises a shaft 1 on which is mounted a gearwheel 2 that meshes with a similar gearwheel 3 actuated by a prime mover 4, such as an electrical mtor.- Two discs or wheels and 6 are mounted on the shaft, for rotation thereby, and are spaced apart a distance slightly less than the width of a film of the commercial type, namely, approximately 35 millimeters. The

discs

5 and 6 are provided with peripheral projections 7 which are properly spaced apart to register with the marginal perforations in the usual motion-picture film.

Two similar, though smaller,

discs

8 and 10 are mounted on the shaft 1, intermediate the

large discs

5 and 6, and are spaced apart a distance slightly less than the width of the film usually utilized in projectors of the home type, namely approximately 16 millimeters. Astorage magazine or spool 11 is mounted above the shaft 1 and accommodates a negative film 12 which is to be reproduced. The

film is withdrawn from the magazine 11 by the rotation of a similar magazine 13 and, in

itstravel between the two magazines, it passes over aguard plate 14 mounted adjacent the peripheries of the

toothed wheels

5 and 6. The guard late, which is shown in detail in Figs. 3 an 4, is preferably sli tly wider than the film 12 and has an opening 15' of .H- sha extending therethrough.

e toothed

discs

5 and 6 project a slight.

distance through the o ning 15 and register with the marginal per orations of the film 12, servin to assist in advancing the fihn in its travel tween the two magazines and to prevent it from slipping.

Two magazines 1 6 and 17 are provided to accommodate a positive film 18 before and after exposure, and the film '18, in its travel between the magazines, passes over a guard plate 20 positioned adjacent the

small discs

8 and 10, through which plate extend small peripheral portions of the said discs. The guard plate 20 is similar in form to the plate 14, although smaller in dimensions.

A light source 21, referably an incandescent lamp, is adjusta ly supported adjacent to the ripheries of the large discs, and the hght t erefrom is concentrated into a beam by a lens system, exemplified by the lens 22, which beam falls upon the negative film as it passes over the central opening in the guard plate 14.

A second lens system, exemplified by the

lenses

23 and 24, is arranged intermediate the guard plate 14 and the guard late 20 ascciated with the small discs8 an 10 and serves to form a reduced image of the illuminated ortion of the negative film on the positive 1m 18.

Although not so shown in the drawings, it it is necessary thatthe entire positive film shall be thoroughly protected against all light except that which comes from the illumlnated section of the negative film, and, to that end, the -entire apparatus, including the light source 21, is preferably enclosed in a light-tight box.

In the operation of the apparatus shown diagrammatically in Figs. 1, 2, 3 and ,4, the fihn 12 travels in the direction indicated by the arrows, while the film 18 travels in the opposite direction. The reason for this opposite travel lies in the fact that the lens system, comprising the

lenses

23 and 24, forms an inverted ima of the illuminated portion of the film 12 on the film 18. If the films were to travel in the same direction, it would be necessary to repeat the printing operation twice in order to obtain a film suitable for projection.

d of advance of the machine is the negative film and the the positive film throu the same as the ratio existing between the circumferenceof the lar e-discs and the circumference of the small lscs, since both airs of reproduce them in a smooth, continuous, and uninterrupted manner. I have been unable discs are rotated in unison byia sing e shaft. Hence, if it is desired that t e positive film shall bejust one-half the length of the negative film from which it is printed, the cir-' cumference of the small. discs is made onehalf as lon asthe circumference of the large discs, and t elens s stem is arranged to form" an'image of the i1 uminated portion of the p when ears are used, and there is but little 1 negative film on the positive film which is one-half the size of the said portion.

When projecting the reducedpositive, if it is assed throughthe apparatus at one-- half t e normal speed at which the large size film is passed through similar apparatus, the same number of separate pictures, or frames, will be thrown u n the screen per second 90 as is the case wit the large film. At the same time, the film-density variations representative of sounds will travel at the pro er speed through the sound-reproducing a paratus, which apparatus usually comprises a hoto-electric cell and a thermionic ampli-. er, to re-create the sounds as recorded on the original film. 1

A modified form of my invention is illus-* trated in Figs. 5 and 6, in which figures the elements analogous to those of Figs. 1 to 4 are numbered slmilarly.

In the alternative form, the reduced image of the illuminated rtlon of the film is caused to pass aroun and below the shaft 1 85 by using a double prism 25. The prism, which is more clearl shown in Fig. 6, has

' a shape which mig t betermed double rhomboidal, the

faces

26, 27, 28 and 30 thereof being arranged at appropriate angles with 40 respect to a lme which passes throu h the light source 21 and the center of the s aft 1. The image is reflected internally of the prism and falls on the film 18 just as though the shaft were not present. It lies within the scope of my invention to support the film 18 on the small discs, nearest the points on the large discs at which the film 12 is supported and advanced. In such event, it is necessary that the intermediate I 60 light source, in order that a small film may be enlarged to the dimensions of films of commercial ty e. This modification, being believed sufliclently obvious, is not illustrated.

I 653 The principaladvantage of my improved film-printing machine lies its ability to reproduce, with exact fidelit the very smallest gradations of the soun record; and to to detect, by ear, any differencev in quality between the sound reproduced from a film made by utilizing my improved printing ma chine and the sound reproduced from the ori 'nal film. I here is no back-lash, such as is present possibility of slippage between the films and the rotating discs.

Inasmuch as the positive filin cannot move relative to the negative film except at the rate determined by the respective circumferences of the several pairs of discs, the reduced sound-record isa microscopically faithful replica of the original.

In addition, my improved printing apparatus is simple in construction 'and easy to operate. Even after continuous use for many months, the accuracy with which it reproduces picture and sound records is not im- 1 paired, since the portions of the device which are subjectto wear have little or no influence on the relative speed at which the films are advanced therethrough.

Although I have illustrated and described only two specific forms of my invention, numerous modifications will be apparent to those skilled in the art to which the inven-' ous film, an axial support therefor, a plu rality of similar though smallerdevices mounted on said axial support intermediate said first mentioned devices, a light source, and means for causing the light from said source to traverse a portion of the space bounded by said devices.

2. In a film-printing machine, a rotatable shaft, a plurality of circular elements mounted thereon ins aced relation and adapted to support and a Vance a film, and a plurality of similar though smaller elements mounted on said shaft intermediate said first mentioned elements, said second group of elementsbeing adapted to support and advance a film of smaller dimensions than said first mentioned 'film, in combination with means for illuminating a section'of said first mentioned film, and means for casting an image of said illuminated-section of said first mentioned film on said smaller film, said imagecasting means being disposed within cylinders of WhlCh said circular elements are t e bases.

3. In a film-printing machine, a rotatable shaft, a lurality of circular elements mounted t ereon in spaced relation and adapted to support and advance a film, and a plurality of similar though smaller elements mounted in said shaft intermediate said first mentioned elements,'said secondgroup of elements bein adapted to support and advance a film 0 smaller dimensions than said first mentioned film, in combination with means for'illuminating a section of said smaiier film, and means for casting an image of said illuminated section of said smaller film on said first mentioned film, said imagecasting means being disposed within the cylinders of which said circular elements are the bases.

In testimony whereof, I have hereunto subscribed 'my name this 15th day of December, 1927.

VLADILIIR K. ZWORYKIN.