US3247788A

US3247788A - Rotary high speed print drum with staggered type columns

Info

Publication number: US3247788A
Authority: US
Publication date: 1966-04-26
Anticipated expiration: 1983-04-26

Description

A ril 26, 1966 R. E- WILKINS ETAL ROTARY HIGH SPEED PRINT DRUM WITH STAGGERED TYPE COLUMNS Filed Nov. 24, 1961 Print Storage Driver l Comp. Driver 1 3a 40 Odd- L Even Comp. 32

Comp.

5 g 4 46 Print 3 Compl.

5 Hold R Fly. 2

A T TORNE Y electro-mechanical apparatus.

United States Patent 3,247,788 ROTARY HIGH SPEED PRINT DRUM WITH STAGGERED TYPE CGLUMNS Robert E. Wilkins, Quincy, and Albert Eng, Broolrline,

Mass, assignors to Honeywell Inc, a corporation of Delaware Filed Nov. 24, 1961, Ser. No. 154,603 2 Claims. (Cl. 101-93) A general object of the present invention is to provide a new and improved apparatus useful for printing using More specifically, the present invention is concerned with high-speed printing apparatus of the type sometimes referred to as line-at-atime printer wherein the printing apparatus has been arranged so that there may be a considerable reduction in the mechanism required for effecting the desired printing operation without any material sacrifice in the speed of operation of the printing apparatus.

Present day electronic data processing systems require that there be printers associated with the output thereof and that these printers be capable of printing large amounts of data at very high speeds inorder to ensure that the data processing system is utilized elliciently. Consequently, line-at-a-time printers have been developed wherein it is possible to print an entire line of print at essentially the same time. In order to effect this type of printing, it has heretofore been the practice to provide a printing mechanism wherein each character that is to printed in a particular line of print is printed by a separate and distinct printing device. One form of apparatus used as a print device may be a hammer which is electromechanically actuated and which is arranged to move the paper on which the printing is to be made against a rotating type wheel which has print characters arranged in spaced relationship around the periphery of the print wheel.

A representative form of printer of this type is described in an article by Earl Masterson et al. entitled A Self-Checking High-Speed Printer," Proceedings of the Eastern Joint Computer Conference, December 19, 1954 in special publication T70. The printer referred to in this article includes a type wheel having 130 columns wherein each column was arranged with a set of characters extending in a column around the periphery of the type wheel. The number of different characters available in each column depends upon the type of printing desired. However, the number of alpha-numeric characters in a set or column may be 51 to include the standard characters of the alphabet, the numbers 0 through 9, and a selected combination of symbols and punctuation marks. In a printer of this type, the print wheel rotates continuously and as a selected character on the print wheel comes into a printing position a hammer is actuated and moves the paper and associated ribbon or carbon against the print wheel so that a print impression is made upon the paper at that particular position. Since there may be 130 characters to be printed in a particular line of print, it has heretofore been necessary to provide 130 separate hammers which are adapted to select the desired character associated with each particular print position in the line.

The building of high-speed printers of this type is costly for the reason that the print wheels are expected to operate at relatively high rotational speeds which may be in the order of 1200 revolutions per minute. Thus, in order to eliect the printing of a particular character from this rotating print Wheel, the timing of the driving of the hammer toward the print wheel must be carried out with a high degree of accuracy to ensure that the printing of the desired character will take place. Since the print wheel stays in continuous motion, a high degree of acl the print wheel.

3,247,788 Patented Apr. 26, 1966 curacy must be achieved in the driving electronics as well as in the associated mechanical equipment. A timing accuracy in the low millisecond range has been successfully achieved in many printers currently on the market. However, the achievement of success in this precise operation has been accomplished at considerable expense by holding close tolerances on all dimensions. When this type mechanism is multiplied manifold times, the costs become considerable and thereby limit the fields where such printers may be used.

In accordance with the principles of present invention, the number of hammers required for effecting line-at-atime printing has been considerably reduced by incorporating a new and novel time-sharing arrangement for a hammer driving mechanism wherein each hammer is adapted to span more than one column of characters on Thisarrangement of the print hammer permits, in its elemental form, a reduction in at least half the number of print hammers needed.

It is therefore a further object of the present invention to provide a new and improved printing mechanism of the line-at-atime type wherein the print hammers used for effecting the printing operation are arranged to span more than one column of characters on an associated print wheel.

In providing a mechanism of the pr-esent type, it is necessary that the characters in each column on the print wheel, which are adapted to be associated with a single hammer, be arranged so that at any particular time the hammer is moved adjacent to the wheel, only a single character can be printed. This requires that the character position of each character he eifectively placed in a space with respect to the characters in the next adjacent column associated with the print hammer to ensure that the hammer moving toward the print wheel will strike only a single character. This arrangement further requires that there be associated electrical control circuitry which will ensure that the desired character will be appropriately related to the desired position on the paper whereon the printing is to take place.

A still further object of the invention is then to provide a new and improved line-at-a-time printing apparatus wherein a print hammer is adapted to span more than one print column and wherein the characters in each print column are displaced relatively to the associated charactersin a print column associated with the hammer so as to ensure that only a single character will be printed as the print hammer is driven toward the print wheel.

Another object of the invention is to provide in combination with the foregoing objects a print storage means having a gating means associated with each column to be printed which is selectively opened in accordance with the positioning of the print wheel and at least a pair of gating means associated with each hammer.

The foregoing objects and features of novelty which characterize the invention, as well as other objects of the invention, are pointed out with particularity in the claims annexed to and forming a part of the present specification. For a better understanding of the invention, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

Of the drawings:

FIGURE 1 is a diagrammatic representation of the invention as it relates to the actual printing operation to be performed; and

FIGURE 2 illustrates diagrammatic logical circuitry which is adapted for use for controlling the operation of the apparatus in FIGURE 1.

Referring first to FIGURE 1, the numeral 10 identifies a print wheel of the type shown in the aforementioned a article. This print wheel is formed with a plurality of columns of characters .arranged in a circumferential path around the periphery of the wheel 10. The number of columns required will be dependent upon the maximum number of characters that must be printed in any particular line of print. The print wheel 19 is shown with characters in columns 11, 12 and 13. These columns are arranged so that the characters therein are displaced relative to each other so that each character in one column lies on a line running parallel to the axis of the wheel and will fall in a space between characters in the next adjacent column. The driving means for the print Wheel 19 is not shown but may be assumed to be a constant speed driving motor.

The printing operation is effected by way of the characters formed on the surface of the print Wheel in the columns as indicated. The actual printing is accomplished by way of a hammer mechanism 14 having a hammer member 16 and a solenoid driving mechanism 13. The driving mechanism includes a solenoid having an electrical coil associated therewith for effecting a desired driving force on the hammer 16 to impel it toward the wheel 10. A spring 19 is provided for biasing the hammer away from the wheel. Not shown between the wheel and the hammer 16 will normally be an appropriate printing ribbon or carbon and a paper on which the impression is to be made. The hammer 16 is arranged to have a width, at least on its print wheel face, such that it will span more than one column of characters on the print wheel 10. As illustrated, the hammer 16 is shown to have sufiicient span to extend across both the columns of 11 and 12.

The energy for driving the solenoid driving mechanism 18 is produced by way of a driver circuit 20, the latter producing a short pulse of current suthcient to cause the solenoid 18 to move the hammer mechanism toward the print wheel and to force the associated paper and carbon, ribbon, or any inking means against the print wheel to effect the desired printing. In order to initiate the operation of driver circuit 20, it is necessary that a signal be generated to indicate that the particular character that is coming next into position on the print wheel 10 is the character to be printed. For initiating a particular printing operation, a suitable print storage circuit 22 is provided and this print storage circuit may store signals representing the particular characters to be printed. The print storage circuit 22 may be assumed herein to be a circuit capable of storing the data to be printed in a single line of print. Consequently, a separate storage means is provided for each character to be printed in the line. For printing one of the characters in column 11, it is assumed that the print storage section 25 contains a character associated with column 11. Similarly, storage sec tion 26 is provided for storing a character to be printed from the column 12 on the print wheel 10. Each character in print storage is adapted to be read out through an associated control gate, such as the

gates

27 and 28. The gate 27 is considered to be the odd gate in that it is adapted to pass to the output thereof the digital data in the character storage section 25 when a printing operation is to take place wtih respect to the odd column, the column 11, at the print wheel 10. The opening of the gate 27 occurs under the control of an odd-even switching circuit 29 which is appropriately synchronized with the print wheel. The output of the circuit 29 may be either the signal 0 or E in synchronism with the displacement of the characters in the columns spanned by the hammer 16. At the time that a particular character is in a printing position on the print wheel 10 in a particular column, a print code generator 30 is adapted to produce an output code comparable to that of the character coming up so that this output may be compared with the data stored in print storage. The comparison circuitry is indicated at 32 and is adapted to produce a single output pulse in the event that a comparison of the output from print code generator 30 and the output of the asso- 4 ciated

gating mechanism

27 or 28 indicates the next character coming up on the print wheel should be printed.

It will be noted that the character storage section 26 has its output coupled to the gating section 28, the latter which has its output buffered to the input of the comparison circuit 32. The controlling signal of gate 28 will be the even signal E and consequently this signal will be derived from the odd-even circuit 29 when the next character up is in column 12 on the print wheel 10.

It will be apparent that the print wheel 10 must have associated therewith sufficient hammer mechanisms to ensure that all columns that have characters thereon may be appropriately printed. Thus, if there should be columns of print in a particular line, it will be apparent that when using the principles described above a total of 65 different hammers must be used in order to effect the printing operation required. Each hammer must have associated therewith circuitry comparable to that associated with the hammer mechanism 14. Thus, a pair of odd-even

gating circuits

35 and 36 are shown connected to the input comparison circuit 38, the latter of which feeds a further driver 40. This driver in turn may be connected to a further hammer mechanism such as illustrated at 14.

Considering the operation of the apparatus illustrated in FIGURE 1, it is first assumed that input data has been inserted into the print storage register 22 in appropriate locations representative of the locations where each character is to be printed in the next line of print. The time that the print storage 22 will be loaded will normally be during the time that the paper is being advanced from one line to the next as is well known in the art. As soon as the paper has been advanced and the print storage circuit has been appropriately loaded, the printing operation can take place. As the printing operation commences, each of the character storage circuits in the print storage circuit 22 will read out in the associated

gating circuits

27, 28, 35 and 36.

Each of the character storage circuits is assumed, as discussed below, to be a recirculating-type circuit such that in the event a character is not read successfully out to the comparison circuit, it may be reinserted back into the register for subsequent analysis. In the event that the character to be printed from column 12 is the letter B, the character B must be stored in the storage circuit 26 and, when the even signal E appears on the gate 28, the code for the character B will be read through the gate 28 into the comparison circuit 32 so that there will be an appropriate comparison made between this code and the print code generator 30. A comparison signal will appear on the output of comparison circuit 32 and thereby activate the driver circuit 20. The driver circuit 20 will produce an output current pulse adequate to cause the hammer 16 to be impelled toward the print wheel 10 to thereby move the paper and the associated ribbon or carbon into a printing relationship with respect to the character B formed on the column 12. It will be noted that when the hammer 16 is adjacent to column 12 the character B will be lying in the space between the B and the C characters in the column 11. Consequently, this arrangement ensures that the fact that hammer 16 may span more than one column of print will not produce an impression in any place other than the particular column which should be active at that particular instant.

If the next character to be printed in column 11 is the character D, the print wheel will continue to operate, and as soon as the character D comes up as indicated by the output from the print code generator, the reading out of the character D in the character storage section 25 by way of the gate 27 will produce a comparison signal in the comparison circuit 32 so that a further printing operation can be carried out. This will continue in all print locations for each line until all characters have been printed.

Referring next to FIGURE 2, there is here illustrated some further logical circuitry that may be associated with the apparatus illustrated in FIGURE I, particularly in those instances where very high-speed printing is to be effected. Included in the illustrated circuitry of FIGURE 2 is further detail of the character storage circuitry associated with each character storage circuit of the print storage 22. The character storage circuit 25 will be seen to comprise a-closed-loop shift register having a pair of recirculation gates 42 and 44. Thus, when a character is read out of the print storage circuit 25, the absence of a comparison signal, as indicated by the presence of a signal COMP, will cause the gate 42 to open so that there may be a recirculation of the character into the character circuit storage 25,

The gating circuit 44 is associated with a special function required only under limited circumstances when the occurrence of a signal in the comparison circuitry is calling for an operation of the hammer mechanism prior to the time that the hammer mechanism has completed an immediately preceding printing operation. Thus, in a very high-speed printer, should the letter A be required to appear in print at column positions 11 and 12, it will be apparent that the hammer mechanism may not be withdrawn from printing the first A in column 11 before the signal calling for the printing of the letter A in column 12 has occurred. Under these circumstances it will be necessary for a second revolution of the print wheel to take place in order to pick up the second A in column 12 before the paper is advanced and a further line of print data is inserted in the storage circuit 22. In order to effect this compensating function, the comparison circuit 32 will produce a signal for activating the driver 20. The comparison signal from the comparison circuit 32 may also be used to set a one-shot multivibrator 46 which will apply a signal to a gate 48 by way of delay circuit 50. The output of the comparison circuit 32 is also applied to gate 48.

In the event that the one-shot multivibrator 46 has been set by one comparison signal from the comparison circuit 32 and a further signal appears at the comparison circuit 32 immediately thereafter, the gate 48 will be open and a set signal S will be applied to a hold flip-flop 52. This hold flip-flop, when set, will feed a signal back to the gate 44 to permit recirculation of that particular character which could not be printed due to the factthat the print hammer had not completed its previous printing operation.

A further function performed by the hold circuit 52 may be the delaying of the paper advance to ensure that characters for that particular line of print will all be printed before the paper does advance. Thus, a paper advance control circuit 54 is .adapted to be switched to a reset state by the presence of a signal when the hold circuit 52 has been set. When all the printing required in a particular line is completed, a print-complete circuit 56 may be activated to set the paper advance control 54 so that a further line of print may be printed.

It will be apparent from a consideration of the foregoing that there has been provided a new and improved printing apparatus wherein it is possible to share the use of a print hammer with more than one column of print.

It will be apparent that this arrangement may be modified so that the print hammer spans more than the two columns illustrated, in which event there must be a further staggering and spacing of characters associated with the particular columns spanned by the hammer mechanism.

While, in accordance with the provisions of the statutes, there has been illustrated and described the best forms of the invention known, it will be apparent to those skilled in the art that changes may be made in the apparatus described without departing from the spirit of the invention as set forth in the appended claims and that, in some cases, certain features of the invention may be used to advantage without a corresponding use of other features.

Having now described the invention, What is claimed as new and novel and for which it is desired to secure Letters Patent is:

1. A high-speed line-ata-time printer comprising a rotary print wheel having formed on the face thereof a plurality of columns of spaced characters with each column extending circumferentially around said print wheel and with each character in each column being positioned on the periphery of said Wheel so that it lies on a longitudinal line parallel to the axis of said wheel which line is located between the characters of an adjacent column of characters, a plurality of print hammers adapted to be driven selectively toward said print wheel to force a medium on which printing is to take place against said wheel, each of said hammers having an effective face width sufiicient to span at least two adjacent columns of characters, and selecting means connected to drive selectively each of said hammers to print from one column or the other of the adjacent columns of characters, said last-named means comprising a data storage register responsive to input signals representative of a single line of print to store for each such line the data to be printed from each. column on said wheel while said wheel rotates through a single revolution, logic means coupled to said selecting means for determining the completion of printing of said line of print in accordance with said stored data, means for normally advancing said medium following each revolution of said wheel to effect the printing of a new line of print after each line of print has been completed in accordance with said stored data, and means responsive to said logic means for holding said advancing means inactive for more than one revolution of said wheel upon a determination that the printing of said line of print was not completed in said one revolution.

2. The apparatus of claim 1 wherein said logic means comprise gating means having one input coupled to said selecting means, a one-shot multivibrator coupled to said one input, delay means coupled between the output of said multivibrator and another input of said gating means, the output of said gating means being coupled to said advancing means and being adapted to control the operation of the latter.

References Cited by the Examiner UNITED STATES PATENTS 2,915,967 12/1959 Gehring et al. 101-93 2,978,977 4/1961 Eckert et a1. l0l--93 WILLIAM B. PENN, Primary Examiner. R. A. LEIGHEY, LEONARD W. VARNER, Examiners.

Claims

1. A HIGH-SPEED LINE-AT-A-TIME PRINTER COMPRISING A ROTARY PRINT WHEEL HAVING FORMED ON THE FACE THEREOF A PLURALITY OF COLUMNS OF SPACED CHARACTERS WITH EACH COLUMN EXTENDING CIRCUMFERENTIALLY AROUND SAID PRINT WHEEL AND WITH SAID CHARACTER IN EACH COLUMN BEING POSITIONED ON THE PERIPHERY OF SAID WHEEL SO THAT IT LIES ON A LONGITUDINAL LINE PARALLEL TO THE AXIS OF SAID WHEEL WHICH LINE IS LOCATED BETWEEN THE CHARACTERS OF AN ADJACENT COLUMN OF CHARACTERS, A PLURALITY OF PRINT HAMMERS ADAPTED TO THE DRIVEN SELECTIVELY TOWARD SAID PRINT WHEEL TO FORCE AND MEDIUM ON WHICH PRINTING IS TO TAKE PLACE AGAINST SAID WHEEL, EACH OF SAID HAMMERS HAVING AN EFFECTIVE FACE WIDTH SUFFICIENT TO SPAN AT LEAST TWO ADJACENT COLUMNS OF CHARACTERS, AND SELECTING MEANS CONNECTED TO DRIVE SELECTIVELY EACH OF SAID HAMMERS TO PRINT FROM ONE COLUMN OR THE OTHER OF THE ADJACENT COLUMNS OF CHARACTERS, SAID LAST-NAMED MEANS COMPRISING A DATA STORAGE REGISTER RESPONSIVE TO IMPUT SIGNALS REPRESENTATIVE OF A SINGLE LINE OF PRINT TO STORE FOR EACH SUCH LINE THE DATA TO BE PRINTED FROM EACH COLUMN ON SAID WHEEL WHILE SAID WHEEL ROTATES THROUGH A SINGLE REVOLUTION,