US 3845709 A
A high speed printer employing an automatic font selection activated by coded indicia on a continuous loop-printing belt cooperating with a plurality of sensors coupled in turn to a counter and decoder system for automatically detecting the particular font speed necessary for controlling the hammer action of the printer.
Description (OCR text may contain errors)
Unlted States Patent 11 1 1111 3,845,709
Gardiner 145] Nov. 5, 1974 MULTIFONT SELECTION 1605.610 9/1971 McDowell et 111. 101/111  Inventor: Derek J Gardiner Sudbury Mass 1605,1113 9 1971 DePuy et al. 101/111  Assignec: lomec Corporation, Southboro, Primary Examine1-Robcrt E. Pulfrey Muss. Assistant ExaminerEdward M. Coven  Filed: Feb. 26, 1973 Attorney, Agent, or FirmDaniel M. Rosen 1211 Appl. No.1 335,862 1571 ABSTRACT 1 A high speed printer employing an automatic font se- 152] U.S.'Cl.. 101/93 C, 101/111 lection activated y coded ind n a ont nu s  1111. C1 B41j 5/10 p-p g belt p t g with a p u y o $911-  Field of Search 101/93 C, 111 sors o p i turn to a ounte and de oder system for automatically detecting the particular font speed  References Cited necessary for controlling the hammer action of the UNITED STATES PATENTS P1111161- 3,115,092 12/1963 Sasaki 101 111 x 1 Claim, 1 Drawing Figure ABC ABC ABC U ""ll l] 11 11 *---*11 9 2/ 2/,
1/ w M p R 12 1 014m 8 comp/mural? V gay 3 2g 111 5: 1
P/mvr 16 HAMMER MULTIFONT SELECTION This invention relates to high speed printers and, more particularly, to automatic multifont selection employable with such high speed printers.
High speed printers such as the type to be described herein typically employ an endless type carrier coacting with a plurality of a number of sets of hammers, one hammer for each character position along a line and a hammer driver for each set of hammers which is timeshared among the hammers of a set.
lmpact line printers typically may be characterized by moving endless print carriers having a number of characters etched, engraved, embossed or otherwise formed on or attached to the carrier surface coacting with a print hammer at each character position on a line so as to effect printing on a print medium such as paper or the like. Storage, control and timing circuitry are utilized to accurately actuate a particular hammer at the precise time a character desired is to be printed and a character is in registration with that position.
Ahigh speed printer operable in accordance with the foregoing general description is described with greater particularity in-U.S. Pat. No. 3,795,186, by Robert H. Curtis et al and assigned to the predecessor in interest of the assignee of the present invention. As is described in the aforementioned copending application, hammer firing must be precisely timed to impact characters at their proper position in order to prevent ghosting, smud gin g, misregistration of printed characters and the like. Thus, the hammer drive circuits must deliver extremely accurate actuation pulses precise in rise time, duration and magnitude. Furthermore, such pulses must be most accurately timed to actuate the hammer precisely as printing is required. lt is conventional in printers, however, to employ various types of fonts for printing. Obviously, where character sizes and sets change from type belt to. type belt, a variation in the timing of the control circuitry actuating the print hammers must be effected in order to more precisely select the timing necessary to correspond to a particular font belt.
Prior art devices have employed variations in font timing by means of an externally actuatable switch which must be moved from one position to another in accordance with the variation of the font set. Other methods have employed replacement of timing circuits by means of manual reinsertion of printed circuit cards and the like corresponding to a particular type'font belt selected.
It is, therefore, the object of the presentinvention to provide an arrangement for use in a high speed line printer which will permit the automatic selection of timing and triggering to occur in response to changing the font belt.
It is a further object of the present invention to enable a single printer to automatically undergo variation in circuit timing in accordance with a predeter'mined coded system located on the font belt itself.
It is still a further object of the present invention to provide a simple and economical'method of varying the internal-timing of a hammer drive for purposes of selecting character sets varying in size in accordance with pluralities of predetermined fonts, the control for the selection being located directly upon the font belt.
The foregoing objects are effected by locating a first and second set of indicia on the font belt coded in aca 2 cordance with the size of the particular font set located on that belt. A sensor mechanismis adapted to transduce the plurality of indicia to provide a coded signal. A decoding circuit is responsive to the coded signal for selecting one of a plurality of font speed timing circuits which, in turn, control the timing to the hammer drive circuits. I
The foregoing objects and brief description of'the present invention will become more apparent from the following more detailed description of the present invention and appended drawing wherein the FIGURE illustrates a logic diagramshowingthe interrelationship of the components of the present invention with a dual indicia belt.
Referring to FIG. 1, a font belt 101is illustrated having a font set 12 located thereon. Directly beneath the font set on the font belt is a first plurality of primary indicia l4 and a second plurality of secondary indicia l6. Relationship between the indicia l4 and the indicia 16 are indicative of the nature of the character font provided in the area 12. Thus, as shown in the FIGURE, the font belt 10 includes a group of secondary indicia 14 for every primary indicia 16. The primary/secondaryrelative position is, therefore, a coded representation of the particular font size contained within the segment l2.
Should the font size of the segment 12 differ from belt to belt, for example, the relative position of the primary/secondary indicia will vary accordingly.'The type belt 10 may be formed of a single loop of steel having a homogeneous characteristic with raised letters and indicia, formed in a well known manner andas illustrated in greater detail in co-pending application, Ser. No. 857,507 filed Sept. 12, 1969 by Richard Holzman, et al and assigned to the predecessor in interest of the assignee of the present invention.
Cooperating with the steel belt for sensing the primary and secondary indicia are sensors Band 20. The sensors 18 and 20, which may be magnetic in nature, operate to sense the raised area corresponding to the indicia 16 and 14 for providing anappr opriate signal therefrom. A suitable form of sensor which may be utilized in conjunction with the present invention is illustrated in copending application, Ser. No. 857,506 filed Sept. 12, I969 by Robert H. Curtiss and assigned to the predecessor in interest of the assignee of the present invention.
The output derived from the transducers l8 and 20 are coupled to a counter 22 which is, in turn, coupled to a decoding unit 24. The output of the transducersl8 and 20 are also coupled to a character generator 26 which is in turn coupled to a comparator 28. Data input is applied along line 30 to a memory 32, and, in turn, supplied to the same comparator 283. The output of the comparator 28 is supplied along a line 34'toa drive control circuit 36. The drive control circuit receives outputs from one of a plurality of selected font timing circuits indicated as 38, 40, and 42 respectively. Obviously, further font selection timing circuits may be em- 3 ploying 6 sets of 64 characters, a primary indicia would appear six times, once for every 64 secondary indicia; in a belt employing 24 sets of 16 characters, a primary indicia would appear 24 times, once for every 16 characters, etc. The requisites of timing and control are fully set forth in US. Pat. No. 3,795,l86 for 6 sets of 64 character belt. The requisites for a timing circuitry for effecting the necessary print cycles to accomplish an operation employing a-character belt of 6 sets of 64 characters is also clearly set forth in said application Ser. No. 876,770, the disclosure of which is specifically incorporated herein by reference. The present invention provides for changing of this timing in accordance with the variation of the character sets employed on a variation of font belt. Thus, the timing provided from circuits 38, 40, and 42 are each coupled by means of suitable coupling to the comparator unit 28 and the drive control 36 in the same manner as illustrated in the said US. Pat. No. 3,795,186 for setting the drive control circuit 36, which, in turn, controls the hammer drive circuit 44 and drives the print hammers 46. A full description of driver control, hammer driver, and printer hammer circuits may also be found in US. Pat. No. 3,795,l86.
The operation of the present invention will now be described in greater detail. Upon removal and replacement of a type belt 10, the machine is activated. Upon activation of the machine, the sensors 18 and 20 operate to transduce pulses in accordance with the relative position of the primary and secondary indicia l6 and 14 respectively. The counter unit 22 responds to an activation signal from the transducer 20 which will set the counter and allow it to continue to count pulses from transducer 20 at a predetermined rate until the transducer 18 picks up a primary indicia signal and resets the counter. Thus, the counter will count to a predetermined total level corresponding to the relative position between the two sets of indicia. The decoder circuit 24 will respond to this predetermined total level for providing a one out of n-outputalong the plurality of out- 'put lines indicated beneath the element 24 to one of the appropriate timing circuits in accordance with the relative positioning of the primary and secondary indicia. Once having selected an appropriate timing circuit, the print hammer timing cycle may be arranged to more precisely and accurately place the printed characters on the paper. It should be noted in connection with the drawing that the print hammer unit 46 operates with the type face 12 in conjunction with an intervening sheet of paper such as is more fully described in US.
Pat. No. 3,795,186.
The timing operation may be accomplished by the use of a three bit number which will allow sufficient variation for any practical number of belts. Since the belts are replacable as a unit, a much more convenient method of automatically selecting the particular font timing desired for driving the hammer in a line printer has thus been disclosed. It is only necessary for variation of the font size to change the belt itself, the indicia marks located thereon providing the indication of the variation in speed timing which the circuit need employ in order to select the desired printing speed.
Thus what has been described above is a multifont capability in a typical line printer such as is described herein.
Other modifications, variations, substitutions and additions may be made to the foregoing description in accordance with the spirit and scope of the invention as will be apparent to one skilled in the art.
What is claimed is:
1. A print timing apparatus for use in font belt printing for printing in accordance with the timing of any of a plurality of fonts having a different number of characters per set, each different font carried on a font belt, said font belt including a plurality of primary indicia and a plurality of secondary indicia, said primary indicia corresponding to each font on said belt and said secondary indicia corresponding to each character on a font, said first and second indicia positioned on said belt relative to each other in accordance with the size characteristic of each said font, said apparatus comprising a plurality of timing means for controlling the speed actuation of said printer in accordance with the size font on said font belt, a first sensor for sensing said primary indicia, a second sensor for sensing said secondary indicia, a counter coupled to said second sensor and responsive to each secondary indicia for accumulating a count corresponding to said sensed secondary indicia, said counter having a reset input further coupled to said first sensor and responsive thereto to be reset by each sensed primary indicia, the total count thus accumulated in said counter corresponding to a font size, decoding means coupled to said counter and responsive to each total level count accumulated in said counter forproviding a unique output, and means coupling each unique output of said decoder to a corresponding one of said plurality of timing means for selecting one of said timing means of said printer.