US3721174A - Character storage apparatus with individually replaceable, accurately located character fonts - Google Patents

Abstract

This disclosure depicts character storage apparatus especially for use in a phototypesetting machine or the like for storage characters for selective presentation at a character display location, including a plurality of discrete character carriers each carrying a font of characters which revolve on a cylinder of revolution when the phototypesetting machine is in operation, the carriers being dimensionally rigid at least in the said cylinder of revolution. The apparatus includes carrier mounting means and means for attaching the carriers to the carrier mounting means such that the characters are located with extreme accuracy.

Description

United States Patent [191 Tidd ]March 20, 1973 [54] CHARACTER STORAGE APPARATUS WITH INDIVIDUALLY REPLACEABLE,

ACCURATELYLOCATED CHARACTER FONTS [75] Inventor: James Alfred Tidd, l-laverhill, Mass.

[73] Assignee: Graphic Systems, Inc., Lowell,

Mass.

[22] Filed: Aug. 30, 1971 [21] Appl No.: 176,222

[52] US. Cl. ..95/85, 95/45 R [51 Int. Cl. ..G03b 15/00 [5 8] Field of Search ..95/4.5 R, 85

[56] References Cited UNITED STATES PATENTS 3,485,150 12/1969 Tortorici et a1 ..95/4.5 R

3,610,121 10/1971 Hanson et al. ..95/4.5 R

Primary Examiner-Samuel S. Matthews Assistant Examiner-Richard A. Wintercorn Atl0rney-R0sen & Steinhilper [57] ABSTRACT This disclosure depicts character storage apparatus especially for use in a phototypesetting machine or the like for storage characters for selective presentation at a character display location, including a plurality of discrete character carriers each carrying a font of characters which revolve on a cylinder of revolution when the phototypesetting machine is in operation, the carriers being dimensionally rigid at least in the said cylinder of revolution. The apparatus includes carrier mounting means and means for attaching the carriers to the carrier mounting means such that the characters are located with extreme accuracy.

13 Claims, 4 Drawing Figures CROSS-REFERENCE TO RELATED APPLICATION The application is related to, but is in no way dependent upon, copending application Ser. No. 43,764 filed June 5, 1970, assigned to the Assignee of the present invention.

BACKGROUND OF THE INVENTION One type of phototypesetting apparatus presently in commercial use includes a character storage drum which carries on a film strip of plurality of character fonts arranged in tandem around the periphery of the drum. The drum is rotated rapidly to bring the characters in sequence before an optical imaging system illuminated by a quickly pulsed light source. A particular character is selected by causing the light source to be pulsed when that character is registered with the imaging system. The end product of such phototypesetting apparatus is a photographic printing plate.

In the practice of phototypesetting, as with all typesetting, a large number of type fonts are made available for selective use according to the specifications of particular jobs. It is desirable that phototypesetting machines have the capability of setting a character from the greatest possible number of fonts with the least expenditure of time and labor.

Many drum-type phototypesetting machines have the capability of storing a number of fonts in tandem around the periphery of the character storage drum; however, in general such machines require that the font combinations be pre-selected and placed on a master film strip which is then secured on the periphery of the drum. In one commercially available machine, font interchangeability is provided by the use of film strips carrying individual character fonts which are attached separately to the periphery of a drum and aligned by means of registration pins.

However, the described arrangement for providing individual font replacement or interchange has a number of serious deficiencies. First, the accuracy with which the character fonts can be positioned and held on the drum, initially and especially after a period of use, is not considered to be acceptable. The registration pins are necessarily manufactured with significant tolerances, as are the apertures in the film which receive the pins. After a period of use, due largely to handling and to the stresses induced in the film strip by high speed rotation of the strip, the apertures are apt to enlarge. Secondly, the described arrangement for providing selective replacement of individual character fonts is unnecessarily time consuming and laborious so much so that in practice some users prefer to replace an asscm bled drum rather than to attempt to replace an individual font strip on the drum. Thirdly, it has been found that because of the dimensional flexibility of a film strip is apt to bow, warp, or be otherwise distorted at high rational speeds. This is particularly serious when the effect is to distort the registration between the characters and associated timing marks which customarily accompany the characters on a font strip. The timing marks are customarily monitored electrooptically by the machines control center in order that the control center may be capable of knowing which character is located at any given time at the character display position or station.

The problem of accurate location of the characters on the drum is particularly acute in machines having the capability of magnifying characters.

OBJECTS OF THE INVENTION It is an object of this invention to provide, for use in phototypesetters and other character display or recording apparatus, improved character storage apparatus for storing characters for selective presentation at a character display station in the apparatus.

It is another object to provide character storage apparatus by which any of a plurality of character fonts can be individually replaced or interchanged with a minimum expenditure of time and effort.

It is an important object of this invention to provide a character storage drum including a plurality of discrete character carriers each carrying a font of characters, which characters are positioned and held on the drum with a high degree of accuracy, not only initially but after long periods of use, as well.

It is still another object of this invention to provide character storage apparatus which provides a rigid backing for the stored characters so as to minimize the possibility of misregistration occurring at high rotational speeds between characters and their associated timing marks.

Further objects and advantages of the invention will in part be obvious and will in part become apparent as the following description proceeds. The features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view, partially exploded, illustrating character storage apparatus constructed according to the teachings of this invention;

FIG. 2 is a section view taken through drum segment 20 in FIG. 1;

FIG. 3 is a perspective view of an alternative embodiment of the invention; and

FIG. 4 is a section view similar to FIG. 2, taken through the FIG. 3 embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 12 illustrate character storage apparatus representing a preferred implementation of the principles of this invention. FIGS. l-2 illustrate a character storage drum 10 intended for use in character display or recording apparatus such as phototypesetters (including photocomposers) and the like, comprising a hub 12 and a plurality oflike drum segments l4, 16, 18, 20 which are adapted to be attached to the hub 12. The drum segments 14, 16, 18, 20 function as character carriers, each carrying a font of characters 22. Whereas each drum segment is shown as carrying one font of characters, it is within the purview of this invention that each segment carrying a number of fonts, for example, a pair of related fonts.

Whereas any of a number of means may be employed for disposing characters on the segments l4, 16, 18, 20 in the illustrated preferred embodiment the characters are recorded on a strip 24 of photographic film which contains, in addition to a font of characters 22, a row of timing marks 26 associated with the characters 22 for providing information useful to a phototypesetting machine's control center in determining the particular character which is located at a predetermined character display station at a given instant. For a description of the associated system as a whole reference may be had to the above-identified copending application, now U.S. Pat. No. 3,631,774.

Each of the drum segments 14, 16, 18, 20 includes a cylindrical portion 28, the outer surface 30 of which supports the characters 22, and a radially extending web 32 connected to the cylindrical portion 28. It can be seen that the characters rotate on a cylinder of revolution which includes the outer surface 30 of the cylindrical portions 28 of the drum segments. Each character is thus presented to the associated character imaging system (not shown) at the same radial distance from the drum axis, and consequently at the same axial position in the imaging system.

In order to provide room within the drum for a light source for illuminating the characters, the web 32 of each segment is connected to the cylindrical portions 28 asymmetrically. It has been found that this asymmetry causes a distortion of the drum at high rotational speeds. To counterbalance the drum, weights 34, 35 are added to the shorter side of the cylindrical portion 28.

It is an important object of this invention to provide character storage apparatus by which characters are stored at predetermined locations with high accuracy. The problem of accurate positioning of the characters on the character storage apparatus has a number of facets. First, the characters must be positioned accurately along the axis of the drum, that is, with respect to an arbitrary reference plane oriented normal to the axis of the drum. In the illustrated embodiment wherein the characters are arranged end-to-end, rather than sideby-side, any error in the axial position of a character will result in a misplacement of the character on the photographic printing plate (not shown) in a direction along the line oftype.

The second source of error is in the timing of a character presentation (by the pulsing ofa light source, for example). Any error in timing of a character presentation will result in a misplacement of a character on the printing plate high or low relative to the line of type. Whereas the timing of character presentation is largely a function of the accuracy of the electro-optic monitoring system which senses and counts the timing marks 26, it is important that the registration of the timing marks 26 with the characters 22 on a particular drum segment be maintained. Any significant distortion of this registration, such as might be caused by centrifugal stresses induced in a loosely held film strip rotating at high angular velocities, is apt to introduce timing errors. In accordance with this invention dimensional stability of the characters and associated timing marks, at least in a cylinder of revolution in which the characters and marks rotate, is provided so as to obviate any such timing errors.

In order to insure accurate axial placement of the characters, in accordance with one implementation of this invention, a film strip 24 carrying a font of characters 22 and associated timing marks 26 is very accurately adhered to the outer surface 30 of the cylindrical portion 28 of each of the segments 14, 16, 18, 20, as by a patterned adhesive 36 disposed on the back of the film strip 24 except in those areas which contain the characters 22 and timing marks 26. Commercially available two-faced adhesive tape may be used as the adhesive binder.

Viewing this aspect of the invention in a broader sense, there is provided by this invention a plurality of discrete character carriers, each carrying a font of characters which is disposed on a cylinder of revolution when the photocomposing machine is in operation, the carriers being dimensionally rigid at least in the said cylinder of revolution. Thus, it is within the compass of this invention to provide, for example, a rigid backing for a font of characters which might be in the form of a transparent planar plate bent into a cylindrical shape and attached to a frame, hub, or other mounting means. Such a strip may be flexed to take a cylindrical configuration, yet be extremely rigid in the cylinder of revolution in which it revolves, so as to preclude any distortion of the synchronization of the characters 22 and associated timing marks during rotation thereof. Such a rigid character as contemplated by this invention minimizes the problem of wear and consequent loss of character positional accuracy such as plagues the conventional film strip arrangements presently in use today and in the past.

In order that the characters, once placed accurately on a rigid carrier, may be positioned very accurately on the drum axis, according to this invention the segments 14, 16, 18, 20 are provided with an accurately formed mounting surface 37, here shown as being on the lower surface of the web 32, which is secured to an accurately machined, molded or otherwise fabricated mounting surface 38 on the hub 12. Zero clearance clamping means, here shown as comprising a pair of springloaded screws 40, 41 received in threaded openings 42, 43 in the drum segments, are provided for clamping together the mounting surfaces 37, 38 of the drum segments and the hub 12. Close tolerance alignment pins 44, 45 fitting in openings in the webs 32, one of which is shown at 46, minimize positional variations in the location of the drum segments orthogonal to the drum axis.

By this expedient, the segments can be attached and detached very rapidly, and yet with extreme positional accuracy in the placement of the characters 22. Thus, rapid interchange or replacement of a font of characters is made possible without any sacrifice whatsoever in the accuracy of the axial positional placement of the characters. All tolerances arising in the zero clearance clamping arrangement shown are in the dimensions of the pins 44, 45 and in the pin receiving openings 46 in the drum segments. These tolerances exist only in the plane of the webs 32 and are not effective axially. Thus, any variations in presented character placement which may result from such tolerances are realized as variations in positioning of the character along the axis of the character imaging system (not shown). Such variations as may result (e.g., 0.005 0.010 inch) are well within the depth of focus of commercially available optical imaging systems, and thus do not result in any degradation of the ultimate photographic printing plate produced.

A plurality of L-shaped baffle members 47 are provided to bridge the gap between the film strips on adjacent drum segments and thereby to maintain a normally dark condition for the electro-optic circuit monitoring the timing marks 26 on the film strips 24.

Thus, by this invention character storage apparatus is provided which permits rapid and easy replacement of character fonts in order that desired combinations of character fonts may be easily and quickly achieved. Further, this is achieved while providing and maintaining extremely high accuracy in the positioning of characters.

The preferred FIGS. l-2 embodiment illustrates the drum segments 14, I6, 18, as being composed of a transparent plastic material, for example, optical quality acrylic. The use of a transparent drum enables the character illuminating beam to be passed through the drum, permitting the drum to be used as a rigid and dimensionally stable backing for the characters. For certain applications, however, a plastic drum may not have the strength necessary to prevent unacceptable distortions. Accordingly, it may be desirable in such applications to provide a drum having greater rigidity.

FIGS. 3 and 4 represent perspective and cross-sectional views of an alternative embodiment of the invention wherein the drum segments, one of which is shown at 48, are composed ofa material having relatively high rigidity, such as aluminum. Because aluminum is not transparent to light, the cylindrical portion 50 of the segment 48 has an opening or cut-away 52, 53 in the areas registered with the characters 54 and timing marks 56 of the film strip 58. As in the FIGS. 12 embodiment, an adhesive 60 may be employed to adhere the strip 58 to the outer surface of the cylindrical portion 50 of the drum segment 48.

Because the FIGS. 3-4 drum segment has much greater rigidity than the plastic FIGS. 1-2 embodiment, it is not apt to distort during rotation and the weights which were desirable to counter-balance the drum segments in the FIGS. 12 embodiment are not necessary. In other respects than those discussed, the FIGS. 3-4 drum segment may be considered to be like the FIGS. l2 segments.

The invention is not limited to the particular details of construction of the embodiments depicted, and it is contemplated that various and other modifications and applications will occur to those skilled in the art.

For example, whereas the FIGS. l-2 embodiment shows four drum segments, it is within the purview of this invention to provide a greater or lesser number of drum segments. As discussed above, the principles of this invention may be implemented in other ways other than the use of a rigid drum segment having a cylindrical portion attached to a web portion; many other structures are contemplated some of which are suggested directly above and others of which are obvious equivalents and alternatives to those described and suggested. Rather than forming the characters photographically on a film strip which is adhered to a character carrier, the characters could be formed directly on the carrier by vapor deposition techniques or could otherwise be disposed on the carriers.

Therefore, because certain changes may be made in the above-described apparatus without departing from the true spirit and scope of the invention herein involved, it is intended that the subject matter of the above depiction shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. For use in a phototypesetting machine or the like, character storage apparatus for storing characters for selective presentation at a character display location, comprising:

a plurality of interchangeable discrete character carriers each carrying a font of characters permanently secured thereto and adapted to be cylindrically disposed on a cylinder of revolution when said phototype-setting machine is in operation, said carriers being dimensionally rigid in said cylinder of revolution, and said characters in said font being positioned in an unobstructed optical path within the boundaries of the dimensionally rigid carrier;

carrier mounting means; and

releasable means for attaching said carriers to said carrier mounting means, whereby said character storage apparatus is capable of carrying desired combinations of individually replaceable and dimensionally stable character fonts.

2. The apparatus defined by claim 1 wherein said carrier includes a film strip on which is recorded said collection of characters, said strip being adhered to said outer surface of said member.

3. The apparatus defined by claim 2 wherein said character carriers each include a radially-extending web portion connected to a cylindrical member defining said cylindrical surface, wherein said carrier mounting means defines a radially extending mounting surface and wherein said means for attaching said carriers secures said web portion of each of said carriers to said mounting surface of said mounting means with substantially no play parallel to the axis of said cylinder of revolution 4. For use in a phototypesetting machine or the like, character storage apparatus for storing characters for selective presentation at a character display location, comprising:

a drum comprising:

a plurality of interchangeable, rigid, discrete drum segments for receiving a like number of fonts strips, one on each drum segment,

hub means, and

means for attaching said drum segments to said hub means; and

a number of discrete font strips equal to the number of drum segments each strip carrying a font of characters; and

means for attaching said font strips to said drum segments, one on each drum segment, whereby said drum is capable of carrying desired combinations of individually replaceable and accurately positioned character fonts, said font strips being positioned to place said characters in an unobstructed optical path through the rigid drum segments.

5. The apparatus defined by claim 4 including registration pin means on said hub means and associated pin receiving openings in said drum segments for minimizing positional variation of said drum elements transverse to said drum axis.

6. The apparatus defined by claim 4 wherein said means for attaching said drum segments provides for attachment of said drum segments to said hub means each independently of all others.

7. The apparatus defined by claim 4 wherein said means for attaching said font strips to said drum segments comprises an adhesive coating disposed on each font strip in a pattern configured to avoid the characters on said strip.

8. The apparatus defined by claim 6 wherein said means for attaching said font strips to said drum segments comprises an adhesive coating disposed on each font strip in a pattern configured to avoid the characters on said strip.

9. The apparatus defined by claim 4 wherein said hub means defines a radially extending mounting surface for receiving said drum segments, wherein said drum segments each have a radially extending surface adapted to mate with said mounting surface on said hub means, and wherein said means for attaching said drum segments provides for attachment of said drum seg ments to said mounting surface with substantially no play parallel to the axis of the drum whereby to optimize the accuracy in an axial direction of the location of said characters on said character storage apparatus.

10. The apparatus defined by claim 8 wherein said hub means defines a radially extending mounting surface for receiving said drum segments, wherein said drum segments each have a radially extending surface adapted to mate with said mounting surface on said hub means, and wherein said means for attaching said drum segments provides for attachment of said drum segments to said mounting surface with substantially no play parallel to the axis of the drum whereby to optimize the accuracy in an axial direction of the location of said characters on said character storage apparatus.

11. The apparatus defined by claim 4 wherein said drum segments are composed of a transparent plastic material.

12. The apparatus defined by claim 10 wherein said drum segments are composed of a transparent plastic material.

13. The apparatus defined by claim 10 wherein said drum segments are composed of a metallic material and have openings therein registered with said characters.

Claims (13)

1. For use in a phototypesetting machine or the like, character storage apparatus for storing characters for selective presentation at a character display location, comprising: a plurality of interchangeable discrete character carriers each carrying a font of characters permanently secured thereto and adapted to be cylindrically disposed on a cylinder of revolution when said photo-type-setting machine is in operation, said carriers being dimensionally rigid in said cylinder of revolution, and said characters in said font being positioned in an unobstructed optical path within the boundaries of the dimensionally rigid carrier; carrier mounting means; and releasable means for attaching said carriers to said carrier mounting means, whereby said character storage apparatus is capable of carrying desired combinations of individually replaceable and dimensionally stable character fonts.

2. The apparatus defined by claim 1 wherein said carrier includes a film strip on which is recorded said collection of characters, said strip being adhered to said outer surface of said member.

3. The apparatus defined by claim 2 wherein said character carriers each include a radially-extending web portion connected to a cylindrical member defining said cylindrical surface, wherein said carrier mounting means defines a radially extending mounting surface and wherein said means for attaching said carriers secures said web portion of each of said carriers to said mounting surface of said mounting means with substantially no play parallel to the axis of said cylinder of revolution

4. For use in a phototypesetting machine or the like, character storage apparatus for storing characters for selective presentation at a character display location, comprising: a drum comprising: a plurality of interchangeable, rigid, discrete drum segments for receiving a like number of fonts strips, one on each drum segment, hub means, and means for attaching said drum segments to said hub means; and a number of discrete font strips equal to the number of drum segments each strip caRrying a font of characters; and means for attaching said font strips to said drum segments, one on each drum segment, whereby said drum is capable of carrying desired combinations of individually replaceable and accurately positioned character fonts, said font strips being positioned to place said characters in an unobstructed optical path through the rigid drum segments.

5. The apparatus defined by claim 4 including registration pin means on said hub means and associated pin receiving openings in said drum segments for minimizing positional variation of said drum elements transverse to said drum axis.

6. The apparatus defined by claim 4 wherein said means for attaching said drum segments provides for attachment of said drum segments to said hub means each independently of all others.

7. The apparatus defined by claim 4 wherein said means for attaching said font strips to said drum segments comprises an adhesive coating disposed on each font strip in a pattern configured to avoid the characters on said strip.

8. The apparatus defined by claim 6 wherein said means for attaching said font strips to said drum segments comprises an adhesive coating disposed on each font strip in a pattern configured to avoid the characters on said strip.

9. The apparatus defined by claim 4 wherein said hub means defines a radially extending mounting surface for receiving said drum segments, wherein said drum segments each have a radially extending surface adapted to mate with said mounting surface on said hub means, and wherein said means for attaching said drum segments provides for attachment of said drum segments to said mounting surface with substantially no play parallel to the axis of the drum whereby to optimize the accuracy in an axial direction of the location of said characters on said character storage apparatus.

10. The apparatus defined by claim 8 wherein said hub means defines a radially extending mounting surface for receiving said drum segments, wherein said drum segments each have a radially extending surface adapted to mate with said mounting surface on said hub means, and wherein said means for attaching said drum segments provides for attachment of said drum segments to said mounting surface with substantially no play parallel to the axis of the drum whereby to optimize the accuracy in an axial direction of the location of said characters on said character storage apparatus.

11. The apparatus defined by claim 4 wherein said drum segments are composed of a transparent plastic material.

12. The apparatus defined by claim 10 wherein said drum segments are composed of a transparent plastic material.

13. The apparatus defined by claim 10 wherein said drum segments are composed of a metallic material and have openings therein registered with said characters.

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