US3074328A - Photocomposing machine - Google Patents

Description

Jan., 22,! 1.963-

L.A Rossano Er-AL momocowosmc MACHINE 2. Sheets-Sheet l F'I-.ed May 13, 1953 Jan. 22, 1963 l.. RossETTo er AL PHoTocouPosmc. MACHINE 2 Sheets-Sheet 2 Filed May 13, 1953 l NV E N 'I'OR LOU/S 90555770 GINO E SOUSSON/ JTTORNEYJ United States Patent O 3,074,328 PHOTOCOMPOSING MACHINE Louis Rosetto, Kings Point, and Gino F. Squassoni, Lynbrook, NX., assignors to Mergenthaler Linotype Company, a corporation of New York Filed May 13, 1953, Ser. No. 354,826 6 Claims. (Cl. 954.5)

This invention relates to photocomposing machines, that is to say, machines wherein images of selected characters are projected opticallyl onto a photographic member.

In many machines of this type, it has been customary to employ character arrays consisting of either a plurality of opaque characters arranged on a translucent background, or a plurality of translucent characters arranged on an opaque background. In view of the wide range assortment of characters necessarily employed in the composition of type for printing, one of the diliiculties encount/ered in the design of such machines is that of projecting any desired character in the array onto the photographic member in focus and positioned relative to a common axis in order that each character composed Iwill be aligned with respect to all the other characters in a sequence. Where the images of selected characters are projected optically onto the photographic member, generally speaking, only the character in the array located on the optical axis will be so properly projected, the images of each of the other characters being displaced from the said axis by a distance depending upon the remoteness of said character in the array from the optical axis.

Character presentation, that is, the projection of anv image of a selected character of a font at a predetermined master position suitable for photographing, is the central problem of photocomposition. Unless the images of all of the characters in the font can be produced at the same master position, the proper alignment and spacing of characters in a sequence, necessary for high quality composition, cannot be achieved. In the past, character presentation has usually involved relative movement between the character array and the optical system, either to bring the selected character onto the optical axis of the optical system, or to bring the optical axis to the selected character. Costly and elaborate mechanism is required to supply these movements, especially in rview of the degree of accuracy demanded; Ifurthermore, shifting of the character font or the optical system before each character is photographed makes for needlessly slow composition.

The present invention aims to avoid the need for relative movement between the character font and the optical system and oers a highly satisfactory and relatively inexpensive solution of the problem. The invention comprises in essence a rapid and eflcient system for selectively projecting various charactersof a font plate in any desired sequence onto a photographic member in proper focus at the optical axis with an absence of distortion and color fringe, and without any movement of the font plate or the associated optical system. In addition, the invention-provides means for producing enlarged or reduced images of the selected characters so that a variety of different font sizes can be composed from the same character font.

Thefdetails will be better understood from the description which follows.

Referring to the drawings:

FIG. 1 is a side diagrammatic view illustrating the components of the present invention;

FIG.' 2 is a view of the font plate and of a shutter mechanism, looking in a direction opposite to that in which the characters to be photographed are projected;

FIG. 3 is a fragmentary perspective view illustrating the control means for the shutter mechanism;

3,074,328 Patented Jan. 22, 1963 FIG. 4 is a perspective view of a portion of the collimating lens unit which constitutes one of the optical components of the invention;

FIG. 5 is a perspective view illustrating an alternative embodiment of the invention; and

FIG. 6 is a perspective view of another alternative optical system.

The apparatus illustrated in the drawings is enclosed in a suitable dark chamber (not shown). Generally speaking, selected characters of a font plate 1 are illuminated one at a time, and images of the selected characters are optically projected at a predetermined master position on a ground glass projection screen 2. The images are photographed one at a time in the order of their selection on a light sensitive film 3, being optically projected from the screen 2 to the llm by a lens unit 4 capable of either enlarging or reducing the images photographed according to the point size of the type characters to be produced.

Preferably, the font plate 1 comprises a plurality of translucent characters on an opaque background. The plate 1 may be made of glass or in the form of a photographic film, or otherwise, and the typographical characters may be arranged thereon in any desired pattern, e.g., the characters may be arranged in rows and columns or in circular fashion. The plate 1 is removable to make possible the substitution of typographical characters of different fonts.

The characters are projected by a source of field' light 5 which is intensified and directed toward the array of characters 4 by a reflector 6 and a condensing lens 7. The condensing lens system makes for relatively even distribution of light over the entire area of the character array.

The characters are individually selected for composition by the operation of a shutter mechanism which permits the field light to pass through the selected character.'

The shutter mechanism may be controlled from a keyboard and comprises a plurality of pivoted horizontal bars 8, one for each horizontal row of characters, and a plurality of pivoted vertical bars 9, one for each vertical column of characters. The horizontal bars 8 are supported at their ends by a pair of side plates 8a (see FIG. 2), which plates are aflixed to the face of a at supporting frame 8b. A central rectangular portion of the frame 8b is cut away to permit passage of the light rays from the selected characters through the frame. 8 are supported in the side plates 8a by pins p which project laterally from both ends of the shutters and pass through holes provided in the plates, the holes serving as bearings for the pins when they rotate to open the shutters. The vertical shutter bars 9 are similarly mounted in reference to a supporting frame 9b.

A s best shown in FIG. 3, the operation of each shutter bar 8 is controlled by a pair of electromagnets 8c and through a mechanical linkage which includes a pivotal arm-8f, operated by the electromagnets, a connecting link 8h, and small crank arm 8g at the extreme end of one of the shutter supporting pins p. The electromagnets are mounted on an L-shaped bracket 8d aixed to the lfront face of the frame 8b. When the electromagnets 8c are energized, the pivotal movement of the arm 8f shifts the link 8h in the direction of the` arrow in FIG. 3 and, through the small crank arm 8g, rocks the associated shutter to open position. A small tension spring 8i, acting on the arm 8f, serves to close the shutter and restore the mechanical parts to their original position when the electromagnets are deenergized. A pair of electromagnets is provided -for the operation of each shutter bar. The electromagnets are arranged adjacent the shutter bars which they control but in staggered relationship on op- The shutter bars corner of the character.

posite sides of the frame 8b, that ,is to say, every other shutter is operated by electromagnets located at the left side of the shutter, and every other intermediate shutter is operated by electromagnets located at the right. The shutters 9 are operated in' precisely the same manner as the shutters 8 by electromagnets 9c disposed at right angles to the electromagnets 8c.

The selection of a character for composition is controlled from -the keyboard of the machine. The depression of a key operates one of the horizontal shutters 8 and one of the vertical shutters 9, thereby exposing a single character in the array 1 to the field light 5.

A multi-lens component 10 and an imaging lensv 11 are positioned in front of the character array 1 and the shutter mechanism.

The multi-lens component 10 comprises a multiplicity of individual collimating lenses 10a, one for each character in the array. 'Ihe collimating -lenses 10a are substantially identical and their optical axes are parallel. The function of the vcollimating lenses is to project the light rays from the selected characters toward the imaging lens 11 as parallel light. There is a definite relation between the characters in the array and their associated lenses. Each character inthe array is located at the center of or in fixed relation to the optical axis of its corresponding lens, and the distance which separates them is-approximately equal to the focal length of the lens.

yTheimaging lens 11 may be a convex lens of high -resolving power, or, at least, the area utilized should be free from aberration or distortion producing characteistics, and its :function is to form an image of the selected character lon the projection screen 2, which image will fall in a master predetermined position at the center of or in fixed relation to the optical axis 11a of the lens 11 to make it possible to photograph characters in proper sequence and in perfect alignment on the film 3.

If the light rays projected by the collimating lenses 10a are to be substantially parallel, it is essential that the multi-lens component 10 be positioned in parallel lrelationship to the character array 1 and, moreover, that the distance between them be equal to the focal length of the lenses 10a. Also, to insure that the maximum amount of light from a selected character is directed toward the appropriate collimating lens, a channeled or honeycomblike element 12 is positioned between the character array and the lens system 10.

The images are formed on the groundglass screen 2, instead of being photographed immediately, so that they can be then magnified or reduced by the lenses 4 with respect to a fixed imaginary reference point, preferably located on the screen in the vicinity of the lower left-hand If this reference point is located on the optical axis of the lenses 4, the characters will be enlarged or reduced by one quadrant of the lenses 4 in the directions above and to the right of character, while at the same time maintaining a fixed left-hand margin and base line for all characters.

It is a known principle of optics that all parallel light rays striking an imaging lens of high resolving power will be brought to focus at the focal point of the lens. In the present invention, the character in the array selected lfor composition is projected -by one of the collimating lenses 10a toward the imaging lens 11 in the form of parallel rays of light, and, even though the parallel rays impinging upon the imaging lens are confined to but a small portion of the total area of the imaging lens, nevertheless an image of the selected character, regardless of its position in the array, will be formed at the focal point and at a fixed position relative to the optical axis. The ground glass projection screen 2 is located at thefocal point or principal focus of the lens 11, so that the images of different selected characters will all be produced aberration or distortion of images, must -be as great as or greater than the area that the lenses 10a occupy in the lens holder 10, or stated another way, the optical axes of all of the individual lenses 10a must fall within the -useable area of the lens 11.

To summarize, a particular character in the array is selected for composition by opening the appropriate pair of shutters, one from the horizontal group `8 and one from the vertical group 9. Light rays from the light source 5 pass through the area of the array occupied by the selected character and are directed through the channeled member v12 to the collimating lens 10a associated with the selected character. The light rays are converted to parallel light by the collimating lens and transmitted to the imaging lens 11, which then forms an image of the character, suitable for photographing, on the screen 2, said image beingpositioned on the screen at the center of or in fixed relation' to the optical axis 11a of the lens 11.

In this way, the images may be photographed on the film 3 in the order that they are projected on the screen 2, the film being moved in a step by step fashion as determined by the width of the characters to be photographed. Since images of each character in the array may be thus produced on the screen 2, each image falling on the optical axis 11a or in fixed relation thereto, a sequence of characters may be photographed on the film in perfect alignment.

An alternative embodiment of the invention is shown in FIG. 5, wherein the light source 5, condenser lens system 7, character font plate 1, shutter assembly 8, 9, channeled member 12, multi-lens system 10, and the imaging lens 11 are all shown mounted on a long supporting base F. These elements are all identical to the elements described in connection with FIG. 1; however, in this embodiment the image formed -by the lens 11 is produced in space, instead of on the ground glass screen 2 of FIG. 1, and the image is then optically projected on the film 3 by an eyepiece unit, generally designated by the reference numeral 15, and a photographing lens system 16. This alternative embodiment adds to the complexity of the optical system, but has the advantage that the illumination requirements are not as great as in the embodiment shown in FIG. 1.

The eyepiece 15 is of a well known type, usually identied with the Kepler telescope, and comprises individual lenses 15a and 15b. The eyepiece serves to reduce the divergence of the light rays from the lens 11 and to concentrate them in the direction of the lens system 16, which latter produces the image on the film 3.

'Ihe lens system 16 includes forward and rearward elements 16a and 1Gb which are positioned in fixed relation to the film 3, and the function of the lens system is to produce an image of the character selected on the film.

Different magnification and reduction ratios can be obtained =by varying the positions of the lenses 15a and 15b of the eyepiece and by varying the power of the lenses. For this reason, the lenses 15a and 15b are movable in either direction along the principal axis of the optical system and, as indicated in FIG. 5, the distances x and "y at which these lenses are located from the fixed lens 11 may be varied. Moreover, the lenses 15a and 15b are removably mounted in their holders so that lenses of different power can be substituted. Although no particular lens and lens position is critical for a given magnification or reduction ratio, the particular eyepiece, design chosen should in each case insure that the exit pupil position, that is to say, the image of the aperture stop of vthe optical system, falls in the principal plane of the leading element 16a of the lens system 16 to permit maximum utilization of the free aperture of the optical system.

Because -the illumination requirement varies as the square of the ratio of point sizes, a neutral density filter 11 may be used to attenuate the illumination in accordance with the point size being photographed, in lieu of varying the intensity of the light source 5 for different point sizes. Thus, the lamp is maintained at a constant intensity required for photographing the largest desired pointsize, and proper filters are selected to reduce the intensity of the field light projecting the image of the character for the smaller point sizes.

In the commercial embodiment of the invention, it may be preferable to make available a plurality of different lenses, each properly pre-positioned, sothat the operator is required merely to select the appropriate combination for a given point size. Such an arrangement, shown in FIG. 6, relieves the operator of the responsibility of interchanging lenses and adjusting their positions. 4In that figure, the forward element 15a of the eyepiece 15 is shown mounted in one of a series of pivotal lens holders 19 and the rearward element 15b in one or more rotatable discs 20. The lens loldcrs 19 are provided with lenses, e.g., 15a', 15a", 15a', which lenses may be selectively brought into operative position on the optical axis 11a or to inoperative position away from the optical axis. Also, eachl disc 20 contains a series of lenses 15b', 15b", 15b", and is rotatable to bring one or another into operative position on the optical axis. The lens holders 19 and discs 20 may be adjusted manually or automatically, as by a perforated control tape, to select the proper combinations for different point sizes. A rotatable disc 21, containing a variety of neutral density filters 17a to 17g, may also be provided to lfacilitate changing the filter for different point sizes.

The invention has been shown only in preferred form and by way-of example and, ofcourse, many variations and modifications may be made therein and in its mode of application which will still be comprised Within the spirit of the invention. For example, shutters individual to each character lin the array may be employed; also, the single light source 5 may be replaced by sources of illumination individual to each character. Moreover, theshutters may be omitted entirely and the characters projected by light flashes instead. It is -tobe understood, therefore, that the invention is not to be limited to any specified form or embodiment, or in any other respect, except insofar as such-limitations are specified in the appended claims.

` What is claimed is:

1. In a photocomposing machine, the combination of a font plate having an array of typographical characters, means for projecting light rays from `any selected character in the array to the exclusion of the other characters, a plurality of collimating lenses, one for each typographical character, for rendering the light rays from the selected characters substantially parallel, a first image forming lens common to all the characters in the array for producing images of the diiferent selected characters at a common predetermined position in a fixed plane, a light sensitive film located in another plane fixed in relation to said first image forming lens, a second image forming lens for projecting the images one after another as they are produced by the first image forming lens onto the light sensitive film, and an for composition in dierent point sizes.-

3.- Acombination as set forth in claim 1, wherein the v adjustable optical means comprises a plurality -of interchangeable forward and rearward optical elements useable 1n different combinations for composition in different point sizes.

4. A combination according to claim 3, wherein the forward optical elements of the adjustable optical means are situated at different points along the optical axis and are mounted in movable supports so that any selected one thereof may be brought into operative position.

5. A combination according to claim 3, wherein the rearward elements of the adjustable optical means are mounted in a rotatable disk which permits any selected one thereof to be brought into operative position.

6. In a photocomposing machine, the combination of an array of typographical characters, means for optically producing images of different selected characters at a common predetermined position in a fixed plane, an adjustable optical means capable of enlarging or reducing said images for composition in different point sizes, an image forming lens system, the light rays being directed toward the lens system by the optical means and said optical means comprising interchangeable forward and rearward optical elements, there being a plurality of such optical elements, some stationed at different points along theeoptical axis and selectively movable into operative position in the path of projection or to inoperative position away from the path of projection, the arrangement being such that different combinations of the optical elements, each useable combination having a fixed exit pupil position, can be selected as the forward and rearward elements of the optical means for composition in different point sizes, and a plurality of different selectable lter elements to attenuate the neutral density of the light rays for different magnification or reduction ratios.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. IN A PHOTOCOMPOSING MACHINE, THE COMBINATIN OF A FONT PLATE HAVING AN ARRAY OF TYPOGRAPHICAL CHARACTERS, MEANS FOR PROJECTING LIGHT RAYS FROM ANY SELECTED CHARACTER IN THE ARRAY TO THE EXCLUSION OF THE OTHER CHARACTERS, A PLURALITY OF COLLIMATING LENSES, ONE FOR EACH TYPOGRAPHICAL CHARACTER, FOR RENDERING THE LIGHT RAYS FROM THE SELECTED CHARACTERS SUBSTANTIALLY PARALLEL, A FIRST IMAGE FORMING LENS COMMON TO ALL THE CHARACTERS IN THE ARRAY FOR PRODUCING IMAGES OF THE DIFFERENT SELECTED CHARACTERS AT A COMMON PREDETERMINED POSITION IN A FIXED PLANE, A LIGHT SENSITIVE FILM LOCATED IN ANOTHER PLANE FIXED IN RELATION TO SAID FIRST IMAGE FORMING LENS, A SECOND IMAGE FORMING LENS FOR PROJECTING THE IMAGES ONE AFTER ANOTHER AS THEY ARE PRODUCED BY THE FIRST IMAGE FORMING LENS ONTO THE LIGHT SENSITIVE FILM, AND AN ADJUSTABLE OPTICAL MEANS ARRANGED INTERMEDIATE THE FIRST IMAGE FORMING LENS AND THE SECOND IMAGE FORMING LENS FOR CONTROLLING THE SIZE OF THE IMAGES PROJECTED BY THE SECOND IMAGE FORMING LENS ONTO THE LIGHT SENSITIVE FILM.

Images