Ultrahigh resolution photocomposition system employing electronic character generation from magnetically stored data

• US 4,446,491 A
• Filed: 10/01/1980
• Issued: 05/01/1984
• Est. Priority Date: 09/15/1978
• Status: Expired due to Term

• Current Assignee: Alphatype Corp.
• Original Assignee: Alphatype Corp.
• Inventors: Tidd, James A., Tidd, Miles H.
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US06/192,846
• Time in Patent Office: 1,308 Days
• Field of Search: 360/39, 360/48, 360/49
• US Class Current: 368/48
• CPC Class Codes: B41B 19/01 having electron-beam tubes producing an image of at least one character which is photographed
• CPC Class Codes: B41B 27/00 Control, indicating, or safety devices or systems for composing machines of various kinds or types computers in general G06F

Abstract

A photocomposition system for composing typeface characters on a CRT display using a magnetic font disc formed of plural variable length character sectors wherein each sector includes successive storage cells containing all of the coded signals necessary to describe a single character image which signals may be retrieved and decoded for use by the CRT to create an optical image of the character. An optical scanner system is disclosed for optically determining the coordinate points on the boundary of an original character design for subsequent encoding into successive 3 bit binary codes representing successive end to end translational movements along the boundaries of the character design being encoded. The translational movements are selected from a subset of a total of 24 possible translational paths wherein the paths making up the subset is continually varying dependent on the general direction of the previous translational path. An electronic printer system is disclosed for retrieving single groups of character identifying translational command codes in response to text composing signals produced on a text editor. Each group of translational command codes is temporarily stored for decoding into coordinate signals used to access a high speed output memory having storage cells corresponding to the coordinates of the elemental areas (dots) on the CRT screen conceptually divided into an elemental area (dot) matrix. Following one complete decoding cycle, the data stored in the high speed output memory is used to cause the CRT to create an image of the character.

Claims

1. A coded font for storing plural alphabet character designs described by groups of successive multi-bit translational commands with each group describing the entire boundary contour of a single alphabet character beginning at a starting coordinate position and successively describing translational movements around the character boundary contour, each successive command identifying either (1) a path selected from a first translational path set consisting of translational paths frequently required in order to describe a character boundary, and uniquely identified by a binary number of X bits or (2) a path selected from a second translational path set consisting of translational paths less frequently required to define a character boundary and uniquely identified by a binary number of 2 X bits, or (3) a large displacement translational path longer than any of the displacement paths of the first and second path sets uniquely identified by a binary number of 3 X bits, comprising

(a) a disc adapted to be mounted for rotation;

(b) a plurality of sequentially ordered, circumferentially spaced, magnetic storage cells formed of material magnetically alterable to store binary signals, said storage cells being arranged into plural circular storage tracks concentrically positioned around the center of said disc to permit the stored signals to be sensed sequentially as the disc is rotated; and

(c) a plurality of character sectors equal in number to the number of character designs stored on the coded font, one said character sector being uniquely associated with each character design, said character sectors being arranged end to end in a predetermined ordered sequence, each said character sector including

(1) a character data field formed of a plurality of said storage cells equal in number to the number of binary bits required to store the starting coordinates plus X times the total number of commands required to identify the associated character boundary contour plus X times the number of commands identifying paths from the second path set plus 2X times the number of commands identifying the large displacement translational path, said storage cells being magnetically altered to store in sequence the X, 2X, and 3X bit binary signals representing the successive translational commands describing the associated alphabet character, and

(2) a non-character data field formed of a number of storage cells preceding said character data field, each said non-character data field having the same number of said storage cells as all other non-character data fields, said storage cells of said non-character data field being magnetically altered to store binary signals identifying the position of the associated said character data field, whereby all of the signals descriptive of a particular character design stored within a track of the disc may be retrieved by rotating the font disc to cause all of the storage cells in which the corresponding character data field is stored to move past a magnetic pick-up succession without interruption.

2. A coded font disc as defined in claim 1, wherein said disc includes an indexing means for actuating an index transducer positioned in predetermined relationship with respect to the hub to cause the index means to produce a signal upon rotation of the disc in syncronism with the passage in reading relationship with a reading head of the first storage cells in each of the circular storage tracks, and wherein said character sectors are positioned on the disc at a predetermined distance from the beginning of each circular storage track as determined by said index means.

6. A font as defined in claim 1, wherein the translational paths forming said first translational path set are less sharply curved than are the translational paths forming said second translational path set.

3. A coded font disc adapted to be mounted on a rotatable hub for use in an ultrahigh resolution photocomposition system adapted sequentially to recreate optical images of typeface characters when the disc is rotated in a predetermined direction past a reading head adapted to read groups of encoded digital signals stored on the magnetic disc in a highly compact form describing sequential translational movements around the boundary of each character image, comprising a plurality of circular storage tracks concentrically arranged around the center of said disc, each said track including a plurality of sequentially ordered, circumferentially spaced, magnetic storage cells formed of material magnetically alterable to store a signal, at least one track including a first character sector having a character data field formed of a plurality of storage cells the number of which is sufficient to record the digital signals describing the sequential translational movements around the entire boundary of one of the characters encoded on the disc and having a first non-character data field formed of a plurality of storage cells within which is recorded digital signals identifying the position of said character data field within said one track, said tracks containing a plurality of additional character sectors corresponding in number to the number of additional characters encoded on the disc, each said additional character sector including a corresponding character data field formed of a plurality of storage cells the number of which is sufficient to record the digital signals describing the sequential translational movements around the entire boundary of the corresponding character and including a non-character data field formed of a plurality of storage cells within which is recorded digital signals identifying the postion within said track of said corresponding character data field, whereby the number of storage cells required to achieve a desired degree of optical image resolution is minimized.

7. A font as defined in claim 3, wherein each said character data field is formed of consecutive storage cells and each said non-character data field is formed of consecutive storage cells whereby all of the signals descriptive of a particular character design stored within a track of the disc may be retrieved by rotating the font disc to cause all of the storage cells in which the corresponding character data field is stored to move past the reading head in succession without interruption.

8. A font as defined in claim 3, wherein the number of bits in each multi-bit translational command forming the set of translational paths defining said first translational path set is less than the number of bits required to uniquely define each of the translational paths in the set of possible translational paths and wherein each encoded binary signal representative of a translational path in said first set is selected from one of a plurality of subsets of such possible translational paths, each said subset being uniquely defined by the general direction in which the previous translational movement along the character boundary took place.

9. A font as defined in claim 8, wherein each encoded binary signal corresponding to translational paths in said first set includes 2 to 6 bits and said first path set includes 8 to 48 paths.

10. A font as defined in claim 9, wherein each encoded binary signal corresponding to translational paths in said first set includes at least 3 bits and the total path set includes 24 paths.

11. A font as defined in claim 10, wherein said first path set includes 24 separate paths starting from a common point in an X, Y orthogonal point matrix to each of 24 peripheral terminal points spaced 3 points from the common point and wherein the first octant of paths starting on the horizontal includes a first path formed of end to end line segments interconnecting points (0,0) (1,0) (2,0) (3,0), a second path formed of end to end line segments interconnecting points (0,0) (1,0) (2,1) (3,1), a third path formed of end to end line segments interconnecting points (0,0) (1,1) (2,1) (3,2) and a fourth path formed of end to end line segments interconnecting points (0,0) (1,1) (2,2) (3,3) and wherein each succeeding octant of paths is formed of a mirror image of the paths contained in the preceeding octant of paths taken along the line joining the two succeeding octants.

4. A font for storing plural groups of encoded binary signals with each group including successive multi-bit translational codes describing the entire boundary contour of a character for use in a photocomposition system having a signal transducer for reading the stored multi-bit translational codes and an index transducer for identifying the signals being read, comprising

(a) a disc containing a central aperture permitting the disc to be mounted on a hub for rotation past the signal and index transducers;

(b) a plurality of ordered, circular storage tracks concentrically arranged around the center of the circular aperture, each said track including a plurality of sequentially ordered, circumferentially spaced, magnetic storage cells formed of material magnetically alterable to store binary signals;

(c) indexing means positioned on said disc for causing the index transducer to produce a signal identifying the first storage cell in the sequence of ordered cells in each track as the first storage cell passes the signal head;

(d) a first character sector formed from a plurality of ordered storage cells commencing with the first storage cell in one said track, said first character sector including a first character data field having a plurality of storage cells corresponding to the total number of bits contained in the multi-bit translational codes describing the entire boundary contour of a single character, said storage cells of said first character data field being magnetically alterable to store sequentially the multi-bit translational codes describing the entire boundary contour of said one character and a first non-character data field formed of a predetermined number of storage cells preceding said first character data field in which binary numbers are magnetically recorded to identify the location of said first character data field;

(e) a plurality of additional character sectors corresponding in number to the remaining number of character contours recorded on the disc and arranged sequentially end to end extending from one track into the next ordered track, each said additional character sector being associated with a particular character design and including an additional character data field formed of a plurality of sequential storage cells corresponding in number to the number of bits contained in the multi-bit translational codes describing the entire boundary contour, said storage cells of each said additional character data field being magnetically altered to store sequentially the multi-bit translational codes describing the associated character contour of the character associated with said additional character sector and an additional non-character data field preceding said additional character data field and being formed of a predetermined number of storage cells equal to the number of storage cells in said first non-character data field, said additional non-character data field storage cells being magnetically altered to record binary signals representative of the position of the associated additional character data field.

5. A font as defined in claim 4 for use in a photocomposition printer capable of electronically recreating optical images of alphabet characters in a plurality of different point sizes from the same sequence of stored multi-bit translational codes including a first group of character sectors for recording a first set of optical images of alphabet characters in a particular typeface style wherein the alphabet characters are proportioned for electronic display in a predetermined point size and a second group of character sectors for recording a second set of optical images of alphabet characters in the same typeface style as the first set wherein the alphabet characters of the second set are proportioned differently than the first set for electronic display in a predetermined point size different from the first set and further including an alphabet directory sector formed from a plurality of ordered storage cells on said disc, said storage cells in said alphabet directory sector being magnetically altered to record binary control signals for instructing the photocomposition system to use the signals in one of the first and second groups of character sectors when recreating images in a selected point size in order to minimize the amount of electronic alteration of the values represented by the stored multi-bit translational codes in order to create the desired character image size.

12. A coded font disc mounted on a rotatable hub for use in an ultrahigh resolution photocomposition system adapted sequentially to recreate optical images of typeface characters when the disc is rotated in a predetermined direction past a reading head adapted to read groups of encoded digital signals stored on the magnetic disc in a highly compact form describing sequential translational movements around the boundary of each character image, the number of encoded digital signals in some groups being different from the number of encoded digital signals in other groups, comprising a plurality of circular storage tracks concentrically arranged around the center of said disc, each said track including a plurality of sequentially ordered, circumferentially spaced, magnetic storage cells formed of material magnetically alterable to store a signal, said tracks including a plurality of character sectors corresponding in number to the number of characters encoded on the disc, each said character sector including a corresponding character data field formed of a plurality of storage cells equal in number to no more than the number of digital signals necessary to describe the sequential translational movements around the entire boundary of the corresponding character and including a non-character data field formed of a plurality of storage cells within which are recorded digital signals identifying the position within a track of said corresponding character data field, the total length of each said character sector being limited solely to the number of storage cells in said corresponding character data and non-character data fields, whereby the number of storage cells required to achieve a desired degree of optical image resolution is minimized.

13. A font as defined in claim 12, wherein each said character data field is formed of consecutive storage cells and each said non-character data field is formed of consecutive storage cells, whereby all of the signals descriptive of a particular character design stored within a track of the disc may be retrieved by rotating the font disc to cause all of the storage cells in which the corresponding character data field is stored to move past a reading head in succession without interruption.