US 3884148 A
The method of this invention may be used with a chain type printer presenting a set of characters for printing and having a memory defining one of the set of characters to be printed along a series of positions constituting a print line. Such printers are adapted to be controlled by a program, for example, the printer in IBM Model 1403. Therefore, each of the customary alphanumeric printing characters of said machine is replaced by a discrete printing element having a much smaller printing surface than the customary characters. Each element is arranged in position relative to the character supporting body to print out the programmed character in one position of a matrix form of x elements in y rows. Instructions are given to the machine to choose a print character for printout of each element position within the matrix boundaries in the form of a binary coded number of eight bits. A series of N=xy separate printouts provides printout over the entire matrix pattern. A matrix array of said smaller printing surfaces each element of which is printed by the selection of one coded character in a separate printout operation of the printer can form any programmed pattern such as that of a selected alphanumeric character.
Description (OCR text may contain errors)
United States Patet Bergeron  Inventor: Louis Bergeron, Ballainvilliers,
France  Assignee: Centre National dEtudes Spatiales,
Paris, France  Filed: Dec. 14, 1972  Appl. No: 315,193
 Foreign Application Priority Data Dec. 15. 1971 France 71.45081  US. Cl. 101/426; 197/1 R  Int. Cl B41j 3/00  Field of Search 197/1 R; 101/426  References Cited UNlTED STATES PATENTS 1,777,622 10/1930 OHare 197/1 3,267,852 8/1966 Gordon 3,550,148 12/1970 Machler.. 3,726,379 4/1973 Isaac 197/1 Primary Examiner-Edgar S. Burr Assistant Examiner-R. T. Rader Attorney. Agent, or Firm-A. W Breiner  ABSTRACT The method of this invention may be used with a chain type printer presenting a set of characters for printing and having a memory defining one of the set of characters to be printed along a series of positions constituting a print line. Such printers are adapted to be controlled by a program, for example, the printer in IBM Model 1403. Therefore, each of the customary alphanumeric printing characters of said machine is replaced by a discrete printing element having a much smaller printing surface than the customary characters. Each element is arranged in position relative to the character supporting body to print out the programmed character in one position of a matrix form of x elements in y rows. Instructions are given to the machine to choose a print character for printout of each element position within the matrix boundaries in the form of a binary coded number of eight bits. A series of N=xy separate printouts provides printout over the entire matrix pattern. A matrix array of said smaller printing surfaces each element of which is printed by the selection of one coded character in a separate printout operation of the printer can form any programmed pattern such as that of a selected alphanumeric character.
2 Claims, 4 Drawing Figures PATENTED HAY 2 0 I975 FIG. :7
METHODS OF IMPROVING PRINTING RESOLUTION IN CHAIN TYPE PRINTERS The present invention relates to the printing art and more particularly to a method of printing documents such as weather charts for instance and to means for performing the same. The object of this method is to increase the detail definition on documents printed, by comparison with documents printed by the prior methods.
The invention is based on the observation that with prior art printing machines the degree of resolution of the traces produced by printing is not very high and that it would be possible to substantially improve resolution without basically modifying the printing machine.
The methods for achieving this objective include recourse to a printing machine of a type well known per se but preferably a chain type high-speed printer equipped with a memory and controllable by a preestablished program. In accordance with the invention, the customary printing characters on such a machine are replaced by a number manifestly larger of ele ments having printing surfaces which are much smaller than those of the customary characters and are differently disposed on the character body to reside in a set of positions for forming a character as a matrix set of the elements. Corresponding instructions are given to the machine to print each element position in the character matrix in order to achieve the desired highdefinition printing.
In the printing method according to this invention a printer of known type is utilized and its customary printing characters such as in a 135 character alphameric font are replaced by a set printing elements having a much smaller surface to each print out one of a set of matrix positions replacing the former character dimensions. Corresponding instructions are given to the printer to print out the set of printing element positions to form a character matrix. The method may comprise the following steps:
a. the place occupied by each conventional character is divided up into a number N x y of areas with x lines and 3' columns;
b. there is assigned to each area a number p of different possible sizes for the area of the printing dot' or spot accomodated therein;
c. the printer is provided with p.N differently arranged printing surfaces (dots or spots); and
d. the printer is so controlled as to enable it to print N times on each line and to cause the entirety of said area to be printed with the selected dot or spot array corresponding to the character or print patterns to be made.
The invention will be more clearly understood from the description which follows with reference to the accompanying non-limitative exemplary drawing, in which:
FIG. 1 shows the manner of dividing up a conventional character in accordance with the invention.
FIG. 2 depicts an example of a print to be made.
FIG. 3 shows the printer characters to be used to obtain the print in FIG. 2.
FIG. 4 shows examples of possible dot shapes in accordance with a more refined aspect of the invention.
For a preferred embodiment of this invention, consideration is first given to a standard printer character (FIG. I) of rectangular shape measuring approximately 2.5mm by 3.3mm (or more precisely one-tenth inch by one-eighth inch). As shown, this character can be divided into a matrix of four times five square areas or compartments, each compartment being therefore substantially 0.63mm (1/40 inch) square. A dot or other element shape can be provided in each of these squares whereby to obtain very-high-definition printing.
It will first be assumed that the shape of this dot is circular. In accordance with the invention, the size of the dot may vary. Preferably, in the practical example herein considered, the size of the dots is caused to vary in discrete values to form a set of seven possible dots". In the event of circular dots being used, their diameter in millimetres may be increased in the following steps:
Diametertmm) 0.08 0.17 0.26 0.34 0.43 0.5] 0.60 Dot No. I 2 3 4 5 6 7 This being so, the printing machine to be utilized for instance a chain type line printer equipped with a memory or storage device and capable of being controlied by a programwill have to have a total number of distinct characters equal to 4 X 5 X 7 140 different printing elements. One example of such a printer is the IBM 1403, which has normally characters.
Reference to FIG. 3 shows four of these printing elements C C C C all corresponding to the upper printing line which is assumed to be formed as shown in FIG. 2. Printing element C prints a dot with compartment a during a first pass by the printer, after which element C prints a dot with compartment [2 during a second pass, element C prints with compartment 0 during a third pass and element C, with compartment d during a fourth pass.
More generally, it will be seen that if a standard character has been divided in N x y compartments (x being the number of lines and y the number of col umns) and if there has been assigned to each compartment a number p of possible dot surface sizes, then the printer must have pN printing elements and the instruction program must provide for N passes without vertical displacement of the paper.
It is to be noted that the weight and hence the inertia of the printing elements may remain of the same order as before even though the printing surface is very small. Therefore, because of the increased printing pressure per unit area, strong paper must be used for the printout unless the printer includes means for suitably ad justing the striking pressure.
The position of a dot on its rectangular support can be coded (in the octal system for example). Thus, if the different compartments are numbered:
1 2 3 4 5 6 7 10 ll l2 13 14 l5 l6 17 20 21 22 23 24 and if the dot sizes are coded from O to 7, where 0 corresponds to a blank space (no printing), then each element print will be coded by a three-position octal number in which the first two positions determine the location of the dot on its support and the third its size (or signal level). Such a code will comprise eight binary bits.
For example, level No. 5 in location 13 will be coded 135 in octal or O1 011 101 in binary.
This and other similar data relating to the different dots can be stored in the memory and used to control the printer.
In the present invention it is also possible to conceive of a more refined aspect in the display of the dots, as portrayed in FIG. 4. The underlying principle here consists in relating the apparent shape of the print spot to its level. This permits direct readings of the signal intensity, which could otherwise be more or less difficult to appraise from the size of the spot surface. At the same time, in the case of a weather chart for example, there will be surfaces that encompass a considerable number of dots all of the same level, after the fashion of parallel-oriented small shadings or punctuated blocks, and it will be easy to distinguish between two contiguous areas of different intensity.
It goes without saying that changes and substitutions may be made in the exemplary embodiments hereinbefore described without departing from the scope of the invention.
1. The method of printing patterns of variable resolution with a printer having a font of characters to be printed out in at least one print position of known dimensions, said printer being equipped with a memory and controllable by a printing program, comprising the steps of 1. replacing the font of characters with a set of printing elements each located in a discrete one of a number N of matrix positions within said dimensions,
2. providing for each of said N matrix positions a plurality of elements of different size,
3. identifying each matrix element including those elements of different size with a separate coded representation to be stored in said memory,
4. controlling the printer to print out N times at each print position to form a print out pattern at said N matrix positions, and
5. identifying a print pattern of said elements to be printed out at each said print position by a corresponding set of said coded representations stored in said memory designating the size of the element to be printed out in each of said N matrix positions.
2. The method of printing defined in claim 1 including the step of providing for each element of different size a distinctive shape.