US2935016A

US2935016A - High-speed printer

Info

Publication number: US2935016A
Application number: US308025A
Authority: US
Inventors: Burton F Miller
Original assignee: Hughes Aircraft Co
Current assignee: Raytheon Co
Priority date: 1952-09-05
Filing date: 1952-09-05
Publication date: 1960-05-03
Anticipated expiration: 1977-05-03

Description

y 1960 YB. F. MILLER 2,935,016

HIGH-SPEED PRINTER 2 Sheets-Sheet 1 Filed Sept. 5, 1952 ZCE m 4 IIE'Z {EZIEZIEZICZJIZII EI'E -E'.1

INVENTOR. JVITJ/t 16' 44/4451,

y 1960 B. F. MILLER 2,935,016

HIGH-SPEED PRINTER Filed Sept. 5. 1952 2 Sheets-Sheet 2 TIE-5 32 [III i L1! WEE-a [ZJEEllZIIEI a 2, IZIEZJIIIIZIIZII INVENTOR. lama/v E Mum, Y

United States Patent HIGH-SPEED PRINTER Burton F. Miller, Los Angeles, Calif., assignor, by mesne.

assignments, to Hughes Aircraft Company, a corporation of Delaware Application September 5, 1952, Serial No. 308,025

2 Claims. (Cl. 101-93) The present invention relates to a high-speed printing system and more particularly to a high-speed printing system for printing in a linear space sequence upon a continuously moving printing medium characters stored in a nonlinear space sequence upon a storage medium.

Although numerous printing systems are available in the prior art, each of these systems is based upon an essentially serial mode of operation. More particularly, the basic components of each prior art system are a storage medium upon which the characters to be printed are stored, a sensing station for sensing the characters stored upon the storage medium in serial time sequence, a printing medium, and a plurality of printing elements for printing the different characters upon the printing medium. In operation, during each printing cycle, the printing elements are moved past a printing station in a fixed sequence, and under the control of the sensing station, printing upon the printing medium is performed at the printing station when the desired printing element is positioned at the printing station.

Serial printing systems possess several inherent disadvantages which seriously limit the applicability of such systems to high-speed printing operations. Firstly, since the printing elements pass the printing station in a fixed .serial sequence, the period of each printing cycle must be sufiiciently long to permit the last element in the sequence to reach the printing station. Therefore, the chiciency of time utilization for such printing systems cannot exceed "the printed characters, the printing medium of the prior art systems is fed intermittently past the printing station.

More particularly, the printing medium is held stationary during each printing cycle and is moved one space at the end of the cycle. This arrangement requires a separate iintermittent feed mechanism, and further reduces the :speed of operation of the system owing to the stopping and starting times.

In addition to the inherent speed limitations outlined "above, the prior art serial printing systems exhibit other --disadvantages with respect to the number of components .required, the number of moving parts, and the necessity for accurate alignment of the moving parts. As a result, serial type printing systems are relatively expensive, opcrate at relatively low speeds, and require intermittent drive mechanisms.

According to one prior art attempt to obtain higher printing speeds, the single bank of printing elements outlined above has been replaced with a plurality of banks each including one printing element for each different character to be printed. Although such a system operates at higher printing speeds, it is still essentially a serial system in which the printing medium is moved intermittently ,;and a single character is printed by'each bank of printing 2,935,016 Patented May 3, 1960 j 2 elements. Furthermore, the multiplied number of print ing elements required in this system increases the cost and complexity of the equipment disproportionately, as compared with the benefits derived from the increased speed.

Another prior art printing system which avoids the printing of a single character at a time is that commonly termed the multibar or gang printer. The printing means of this system includes a plurality of type bars mounted in side by side relationship adjacent to the printing medium, each bar including type representing all of the dilferent characters to be printed. In operation, each bar is displaced longitudinally, in accordance with a stored signal,

until the corresponding characters on all the bars are aligned to form an anvil behind the printing medium. When the condition of alignment is attained a printing hammer is energized to strike the printing medium against the bars.

Even though multibar printers are capable of printing more than one character at a time, the mode of operation of these printers remains essentially serial, that is each bar may be considered asoperating in serial fashion. Therefore, multibar printers are subject to each of the inherent limitations outlined above. In addition, it is clear that multibar printers require separate feed and control mechanisms for each of the bars, and further control mechanisms for actuating the printing hammer only when proper alignment of the bars has been attained. Furthermore, although printing speeds of the order of characters per second have been obtained with multibar printers, such speeds are far below the desired high speed requirements.

The prior art has proposed numerous other modifications of serial printing systems in order to attain higher printing speeds. For example, several systems incorporate a continuously moving printing medium to eliminate the time consumed for starting and stopping the medium and to eliminate the intermittent feed mechanism. However, as higher printing speeds are attained with such systems, the relative movement between the printing medium and the printing element during the interval of contact therebetween has resulted in a blurred image being produced upon the printing medium. As a result, the speed of operation of these systems becomes limited by desired quality of the printed character.

The present invention discloses a high-speed printing system which overcomes the above and other disadvantages of the prior art printing systems. According to one basic feature of the present invention, the characters to be printed are stored upon a storage medium in two-dimensional space sequence, one dimension representing the diiferent characters and the other representing the time sequence in which the characters are to be printed. On the other hand, the characters are printed upon the printing medium in one-dimensional space sequence corresponding to the last-named space sequence on the storage medium. Stated differently, the characters are printed upon the printing medium in a space sequence corresponding to the time sequence of storage of the characters on the storage medium. With the arrangement of this invention, the characters need not be printed in a time sequence corresponding to the storage time sequence, and more than one character may be printed at a time.

Considering this basic feature more particularly, the printing system of the present invention includes a plurality of signal sensing devices positioned in the path of movement of the storage medium, one for each different character, and a corresponding plurality of printing elements positioned along the path of movement of the printing medium, each printing element being actuable in response to energization of the associated signal sensing device. The plurality of signal sensing devices are spaced from each other in two dimensions corresponding to the two-dimensional space sequence on the storage medium. Stated differently, the signal sensing devices are spaced from each other in a first dimension corresponding to the character spacing sequence on the storage medium, and in a second dimension corresponding to the direction of movement of the storage medium. On the other hand, the printing elements are spaced from each other in a single dimension corresponding to the second dimension of the space sequence of the signal sensing devices.

According to another basic feature of this invention, the printing medium is moved continuously, but blurring of the printed characters is eliminated by preventing any relative movement between each printing element and the printing medium during the interval of contact therebetween. More particularly, the printing system of this invention eliminates blurring by providing means for moving the type face of each printing element, at least during the interval of contact between that element and the printing medium, the movement of the type face corresponding to the movement of the printing medium. In this manner, substantially zero relative velocity is maintained between the type face and the printing medium.

The type face moving means, according to one embodiment of this invention, includes means for movingthe type face at the same velocity and in the same direction as the printing medium whenever the type face is in a position to engage the medium. On the other hand according to another embodiment of this invention, the type face moving means moves the type face only during the period of its contact with the printing medium.

Each printing element, according to one embodiment of the invention, comprises a rotating drum having character type faces on the periphery thereof and a printing hammer for engaging the printing medium with the character type faces, the printing hammer being responsive to an output signal from the corresponding signal sensing device. The velocity of the moving printing medium and the linear velocity of the character type faces are substantially the same so that during the period of engagement of a type face with the printing medium, there is zero relative velocity therebetween.

In another embodiment, the printing element comprises a pivoted printing member engageable with the printing medium in response to an electrical signal from the. corresponding signal sensing device. The friction between the printing member and the printing medium during the engagement period causes the printing member to rotate about its pivot point, this rotational movement resulting in zero relative velocity between the printing medium and the printing member during the period of engagement therebetween.

By combining the above-mentioned features, the printing system of the present invention is capable of operating at relatively high speeds, such as 3000 characters per second, to produce high quality imprints. In addition, the system requires no intermittent feed mechanism for either the printing medium or the printing elements. Furthermore, the printing system of this invention is capable of printing more than one character at a time without requiring the duplication of elements inherent in prior art systems.

It is, therefore, an object of this invention to provide a high-speed printing system for printing in a linear space sequence upon a printing medium characters stored in a non-linear space sequence upon a storage medium.

Another object is to provide a high-speed printing system for printing in one-dimensional space sequence upon a printing medium characters stored in two-dimensional space sequence upon a storage medium.

An additional object of this invention is to provide a high-speed printing system in which characters stored in a predetermined time sequence upon a storage medium are printed upon a printing medium in a space sequence corresponding to the predetermined time sequence.

A further object is to providea high-speed, high-quality number of different characters to be printed. .tion, sections 13A through 13E represent the first through fifth time intervals, respectively.

printing system in which the printing medium is continuously moving.

i Still another object is to provide a high-speed printing system in which the printing medium is continuously moving, and wherein there is no relative movement between the printing medium and each printing element during the period of contact therebetween.

A still further object of this invention is to provide a high-speed printing system for printing in one-dimensional space sequence upon a continuously moving printlng medium characters stored in two-dimensional space sequence upon a storage medium.

The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which several embodnnents of the invention are illustrated by way of examples. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention. p

Fig. 1 is a schematic diagram of the printing system of this invention;

Fig. 2 is a plan view of a portion of the storage member shown in Fig. 1, upon which the rnformatron to be printed is stored, showing the location of the signal sensing devices with respect thereto;

Fig. 3 illustrates diagrammatically the relative positions of the printing medium during progressive time mtervals of printing; 7

Fig. 4 is an enlarged perspective view of the printing drum of Fig. 1; l

Fig. 5 is a view similar to Fig. 2 of a portion of the storage member, together with another arrangement of the signal sensing devices; V

Fig. 6 illustrates diagrammatically the printing operations resulting from the arrangement of the signal sensing devices of Fig. 5; and

Fig. 7 is an enlarged perspective view of another embodiment of the printing means of this invention.

Referring now to the drawings, there is shown in F g. ,1 a printing system, according to this rnventlon, wh ch comprises a reference or storage member 11 upon wh ch the information to be printed is stored, a s1gnal sensing apparatus 23 for sensing the information stored on mem ber 11, a printing member 31 upon which the stored information is to be printed, and a printing means 3l responsive to signal sensing apparatus 23 for prmtrng the stored information upon-printing member 31. Although storage member 11 and printing member 31 may take any desired form, in Fig. l the members are 11- lustrated as tapes. In addition, although the particular type of storage medium forms no part of this invention, it will be assumed, for purposes of illustration, that storage member 11 is a magnetizable medium upon which information is stored in the form of polarized magnetization.

One arrangement of storage member 11 is illustrated inFig. 2 in which the storage member is divided into a plurality of'parallel longitudinal signal tracks 12, each track representing a different character to be printed, and

a plurality of transverse sections 13, representing intervals of time. By way of example, tracks 12A through 12E represent the characters A through E, respectively, the total number of tracks being determined by the total In addi- Whenever a character of information is to be stored on storage member 11, only one track per section is magnetized. For example, in Fig. 2 the term *CABBA" isstored on the storage member, this term being'chosen tent, as set forth below. The characters C is stored 'on track 120 by magnetizing section 13A thereof representing the first time interval. Character A, in turn, is stored by magnetizing track 12A in section 13B representing the second time interval, and character B is stored by magnetizing track 12B in section 13C, representing'the third time interval. Similarly, the remaining characters B and A are stored in time sections 13D and 13E, respectively.

From the above method of storing the signals, it is seen that the signals are stored in the proper space sequence, meaning, C appearing on the storage medium before A," etc., but in a nonlinear relationship, that is, the signals are stored in the various respective parallel tracks. In other words, the signals are stored on the storage member in two-dimensional space sequence, parallel longitudinal tracks 12, representing a first dimension and transverse sections 13 representing the other of said two dimensions. Still another way of explaining the positioning of the informational signals on the storage member is to consider the plurality of parallel longitudinal tracks as a space sequence across the storage member and to consider the transverse sections as representing time intervals along the storage member. Therefore, positioning each signal upon a particular track and a particular section could be described as storing the signals in a predetermined space sequence and a predetermined time sequence. The reasons for using this method of storing information will be explained more fully below. a

-It should be noted that various other methods of storing information could be adopted and the above is merely described for illustrative purposes. For example, instead of storing information upon a magnetically recorded track it could be stored on a perforated track or a photographically recorded track, the disposition of characters following the same pattern as described above. In addition, although storage member 11 is illustrated as a magnetic tape, other storage devices could be used, such as a magnetic drum in which parallel signal tracks 12 would be spaced around the circumference of the drum rather than longitudinally.

Storage member 11 is moved in the direction of arrow 22, as shown in Fig. 1, at a constant linear velocity, by a power means 14 coupled in any conventional manner to a feed drum 21. As the storage member moves in the direction of the arrow, it passes signal sensing apparatus 23 which includes a series of signal sensing devices 23A through 23E positioned adjacent to and underlying tracks 12A and 12E, respectively. Each signal sensing device is spaced one transverse section from each adjacent signal sensing device, as shown in Fig. 2. The signal sensing devices are positioned along the storage member to compensate for the linear disposition of printing means 30, which will be explained below more fully. More particularly in the embodiments shown in Figs. 1 and 2, signal sensing device 23A during the first time interval is positioned adjacent track 12A and beneath transverse section 13A of the track. Signalsensing device 2313 lags one transverse section behind signal sensing device 23A and is positioned adjacent track 12B, underlying transverse section 13B; signal sensing device 23C lags one transverse section behind signal sensing device 23B and is positioned adjacent track 120, underlying transverse section 13C;"signal sensing devices 23D and 23E are similarly positioned and are spaced one transverse section behind the preceding signal devices.

It is, therefore, seen that the sensing devices form a staggered diagonal column across storage member 11, as shown in Fig. 2. Stated differently, the signal sensing devices are positioned in the path of movement of member 11, as indicated by arrow 22, and are spaced from 1 each other in two dimensions, corresponding to the track spacing and time interval spacing, respectively. It should -be noted, however, that any other system of storing-the..-

' each drum.

signals on the storage member may be used as long as a corresponding arrangement is utilized for the printing means, as explained more fully below.

Referring again to Fig. 1 and considering signal sensing apparatus 23 in detail, each signal sensing device includes a magnetic reading head 24 having an air gap 25, and an excitingcoil 26 wound around'head 24. When a magnetized section 13 on one of the signal tracks passes air gap 25 of the associated signal sensing device, an output pulse or signal will be induced in exciting coil 26. The signal or pulse thus induced is amplified by an amplifier 28 and transmitted through a conductor 29 to its respective printing means 30.

Although electromechanical transducers are shown as signal sensing devices, the particular sensing device utilized does not form a part of this invention and any sensing or detecting element that is capable of operating at a relatively high speed may be utilized. In addition, the signal sensing devices could be positioned above rather than beneath the storage member provided that the magnetized section is capable of energizing the sensing device.

Referring now to the printing portion of the system, as set forth above and as illustrated in Fig. 1, printing member 31 is in the form of a printing tape fed from a second feed drum 32. The second feed drum is coupled to power means 14 through any conventional linkage 15. Second feed drum 32, and, therefore, printing tape 31, is driven from power means 14 at a constant velocity, printing tape 31 moving in the direction of arrow 33. It should be noted that printing tape 31 could be driven from a separate power means, so long as the movements of storage member 11 and printing tape 31 are synchronized, as explained more fully below.

Printing means 30, for printing the information upon printing member or tape 31, includes a plurality of printing drums 35, a corresponding plurality of printing hammers 41, and a print element, such as a carbon transfer element 38 interposed between printing drums 35 and printing tape 31. The total number of printing drums 35 is determined by the total number of different characters to be printed and, for illustrative purposes, five printing drums 35A through 35E for printing characters A through B, respectively. Drums 35A through 35E are positioned adjacent to and underlying printing tape 31 and are aligned with respect thereto, as shown in Fig. 1. Each printing drum 35 is rotated from a conventional power source '16 at a constant angular velocity of such magnitude that the tangential velocity at the outermost surface of the drum is equal to the linear velocity of printing tape31. The reason for rotating the drums will be explained in detail below. It should be noted that printing drums 35 also may be driven from power means 14 by any conventional linkage, so long as the proper tangential velocity is obtained.

Although numerous types of printing drums may be employed in the system of this invention, there is shown in Fig. 4 an enlarged perspective view of one form of printing drum 35A for printing character A. As shown in Fig. 4, printing drum 35A includes a cylindrical member 36 and four raised type faces 37 equally spaced around the periphery of member 36, each type face bearing the character A. It should be noted that four type faces 37 have been shown merely for purposes of illustration, and that any other number of faces may be provided for It will be apparent however, that, for a given speed of rotation of each drum, the speed of printing is directly proportional to the number of type faces on the drum.

Considering now printing hammers 41 in detail, it will be seen from Fig. 1 that each hammer is the armature of a solenoid 42, the total number of solenoids being determined by the number of different characters to be printed. Each solenoid 42 also includes a winding 43 which is connected to the associated conductor 29 In tion of the storage member.

operation, when a solenoid winding, such as winding 43A,

receives a signal from signal sensing device 23A, hammer 41A is extended into engagement with printing tape 31 "thereby forcing the tape and transfer element 38 into engagement with one type face 37A of printing drum 35A. As a result, a pressure imprint of the character A is produced upon printing tape 31.

Printing hmnmers 41A through 41E are positioned in alignment with and overlying printing tape 31, each hammer 41 being spaced from adjacent hammers a distance equal to the spacing between adjacent signal sensing devices 23. Stated differently, since the spacing between adjacent signal sensing devices 23 is equal to the length of one transverse section of storage member 11, as shown in Figs. 1 and 2, the spacing between adjacent printing hammers 41 is equal to the length of one transverse sec- In addition, as shown in Fig. l,- the relative positions of printing hammers 41A through 41E corresponds to the relative positions of sig- 'nal' sensing devices 23A through 23E, respectively. In

other words, printing hammer 41A is positioned first, while printing hammer 41E is positioned last in the direction of travel of printing tape 31.

In operation of the printing system of Fig. 1, it will be assumed that the term CABBA is to be printed, as

set forth above. As previously explained, the term has been stored on storage member 11 by magnetizing the proper transverse sections of the C, A, and B tracks. Storage member 11 commences to move at a constant velocity in the direction of arrow 22 and, at the same time, printing tape 31 starts to move in the direction of arrow 33 at the same linear velocity as the storage member.

As first time interval section 13A of storage member 11 passes signal sensing device 23A, which is the first sensing device positioned in the line of travel of storage 'member 11, no signal is induced in signal sensing de- As first time interval section 13A moves under signal sensing device 23B, second time interval section 13B moves under signal sensing device 23A. Since there is an A stored in second time interval section 13B, a signal will be induced in signal sensing device 23A. The signal vis then amplified by amplifier 28A and transmitted through conductor 29A to winding 43A of solenoid 42A which causes hammer 41A to engage printing tape 31. The printing tape and transfer element 38 are forced into "contact with drum 35A, thus printing the character A upon printing tape 31.

At this same instant, time section 13A appears under signal sensing device 233 which lags on one time section behind signal sensing device 231A, as previously described.

Since there is no B in the first time section, no signal is induced in signal sensing device 2313. Similarly, no signal will be induced in any of signal sensing devices 23C through 23E. Accordingly, during the second time interval, the character A is printed upon tape 31, as shown in the second line of Fig. 3.

When third time interval section 130 of storage mem ber 11 is under signal sensing device 23A, second time interval section 13B is under signal device 238, and first time interval section 13A is under signal sensing device 23C. Since there is no character B in the second time interval section and no A in the third time interval Jsection, signal sensing devices 23A and 233 will not receive any signal. On the other hand, since the character C is stored in first time interval section 13A, signal "sensing device 23C receives a signal which is amplified by amplifier 28C and is then transmitted through conductor than one time interval section apart.

L29C. to'winding 43C of solenoid 42C. Energization of winding 43C causes hammer 41C to engage printing tape 31' forcing .the printing tape and carbon transfer element 38into contact with printing drum 35C, thereby, printing character C on printing tape 31, as shown in the third line of Fig. 3.

It should be noted'that even though the characters A and C were not printed in the same time sequence as they were stored on storage member 11, that is A was printed before C, these characters appear in the proper space sequence, that is C'before A on the printing tape. In other words, although the characters A and C were printed in a time sequence different from that in which they were stored, they are printed in a space sequence corresponding to the time sequence of storage. As pointed out below, there may beinstances in which the printing and storing time sequence are identical. However, with the printing system of this invention, the space sequence of the characters on printing tape 31 always corresponds to the storage time sequence or to the longitudinal space sequence on storage member 11.

When fourth time interval section 13D is under sensing device 23A, third time interval section is under signal sensing device 23B. Since the character B is stored in third time interval section 13C, signal sensing device 238 receives a signal which is amplified and transmitted to winding 43B of solenoid 42B. As a result, printing hammer 41B is actuated, and the character B is printed on printing tape 31 in the space immediately following the character A, as shown in the fourth line of Fig. 3.

It is to be noted that the characters A and B were printed not only in the space sequence corresponding to the time sequence of storage, but in the same time sequence. This result follows from the relationship of the positions of signal sensing devices 23A and 233 with respect to the path of movement of storage memberll. Stated differently, since signal sensing devices 23A and 23B are spaced one time interval section apart in the direction of travel of storage member 11, and since the characters A and B are recorded on storage member 11 one time interval section apart, these characters were printed in a time sequence identical to that in which they were stored.

It should be apparent that this result will follow also for signal sensing devices 23 which are spaced more For example, if the character C had been recorded in time interval section 13D instead of time interval section 13A, the time sequence of'printing would have been A, B, and C. In any event, whether or not the characters are printed in the same time sequence, they are always printed in the proper space sequence.

When fifth time interval section 13E is under signal sensing device 23A, fourth time interval section 13D is under signal sensing device 23B. Since the character B is stored in .fourth time interval section 13D and the character A is stored in fifth time interval section 13E, signal sensing devices 23A and 23B are energized and actuate printing hammers 41A and 41B, respectively. As a result, the characters A and B are printed simultaneously upon printing tape 31, as shown in the last line of Fig. 3.

- It is tobe noted that, in this instance, the characters A and B were printed in the proper space sequence upon printing tape 31, even though they were printed long as the spacing corresponds to the spacing between the associated signal sensing device.

Summarizing the operation of the printing system of this invention, it should be apparent that characters stored in two-dimensional space sequence on a storage member are printed in one-dimensional space sequence upon a printing member. More particularly, the two dimensions of the storage member correspond respectively to the diiferent characters to be printed and to the time sequence of storage of the characters, while the space sequence upon the printing member corresponds .to the time sequence of storage. The characters may be printed upon the printing member in a time sequence either identical to or different from the storage time sequence, depending upon the relative positions of the stored characters as compared with the relative positions of the signal sensing devices. In some instances, when the time sequences are different, more than one character may be printed at the same time upon the printing member.

In the printing system described thus far, it has been assumed that signal sensing devices 23 are spaced diagonally in the direction of travel of storage member 11, as shown in Fig. 2. It should be apparent, however, that the signal sensing devices may be arranged in numerous other relative positions without departing from the spirit and scope of this invention, as defined in the appended claims. The only limitation imposed upon the relative positions of the signal sensing devices is that the printing devices be arranged in corresponding relative positions, as set forth above.

Referring now to Fig. 5, there is shown another arrangement of signal sensing devices 23 with respect to storage member 11. As in Figs. 1 and 2, storage member 11 is divided into longitudinal signal tracks 12A through 12E, and transverse time interval sections 13A through 13E. Similarly, for purposes of comparison, it is assumed that the term CABBA is stored in member 11, the consecutive letters of the term again being stored in time interval sections 13A through 13E, respectively.

In the embodiment of Fig. 5, however, signal sensing devices 23A through 23B are arranged in an entirely difierent manner. More particularly, signal sensing device 23E is positioned first in the direction of travel of storage member 11 as indicated by arrow 22.

Signal sensing devices

23D, 23B, 23C, and 23A are arranged in lagging order behind signal sensing device 23E, each device being spaced one transverse time interval section from the adjacent device in the order specified.

As pointed out above, the printing hammers are arranged in a corresponding order with respect to the printing tape; More particularly, the arrangement of the printing hammers corresponding to the arrangement of the signal sensing devices of Fig. is 41E, 41D, 41B, 41C, and 41A, as indicated diagrammatically in Fig. 6.

In operation, it will be clear that no magnetized section will overlie an associated signal sensing device either at the instant in time represented by Fig. 5 or in the immediately following time interval. Accordingly, as storage member 11 is moved in the direction of arrow 22, no printing will occur until the first time interval section 13A is directly over signal sensing device 230. The relative positions of the printing tape at the instant in time represented in Fig. 5 and during the immediately following time interval are represented diagrammatically in the first two lines, respectively, of Fig. 6.

Consider now the period during which first time inter- I val section 13A is directly over signal sensing device 230.

Since the character C is recorded in first time interval section 13A, this character is printed on the printing tape. On the other hand, none of the other signal sensing devices is energized and, therefore, no other characters are printed during this period. This result is indicated diagrammatically in the third line of Fig. 6.

During theneXt time interval, first time interval sec tion 13A overlies signal sensing device 23A, second time interval section 13B overlies signal sensing device 23C, and third time interval section 13C overlies signal sensing device 23B. Since the character B is stored in third time interval section 13C, this character will be printed on the printing tape, as shown in the fourth line of Fig. 6.

When second time interval section 13B moves over signal sensing device 23A, third and fourth time interval sections 13C and 13D will move over

signal sensing devices

23C and 238, respectively. Since the characters A and B are recorded upon second and fourth time interval sections 13B and 13D, respectively, these characters will be printed simultaneously, as illustrated in the fifth line of Fig. 6.

The only remaining character to be printed is the character A stored in fifth time interval section 13E. Obviously, this character will not be printed until fifth time interval section 13E overlies signal sensing device 23A, that is three time intervals after the last-named printting. At this time, the relative position of the printing tape will be as indicated diagrammatically in the last line of Fig. 6.

Summarizing the operation of the arrangement of Fig. 5, it can be seen that the characters are printed upon the printing member in a space sequence corresponding to the longitudinal space sequence of the characters stored upon the storage member. Stated difierently, as in the arrangement of Fig. 1 and 2, the arrangement of Fig. 5 results in a space sequence of the characters on the printing member which corresponds to the time sequence of storage on the storage member, even though the time sequence of printing does not correspond to the time sequence of storage.

Referring again to Fig. 3 and Fig. 6, it will be noted that the term printed on the printing tape appears reversed, that is, it is printed from right to left instead of from left to right. There are numerous conventional methods for reversing the order of printing so as to present the printed matter in conventional form. For example, after the printing operation upon printing tape 31 has been completed, the printing tape may be subjected to a conventional transfer process in which the characters on the tape are transferred to any conventional printing medium, such as paper. In this manner, printing tape 31 may then be cleaned and reused in the printing system. On the other hand, when it is desired to produce the final printing upon printing tape 31, each character on type face 37 may be inverted from the position shown in Fig. 4. In this manner, in the illustrative example, the term CABBA would be printed as VHEIVOH on printing tape 31. In addition direct printing in the proper order may be obtained by reversing the sequence of the printing elements and the direction of movement of the printing tape.

As was previously stated, a primary object of the present invention is to obtain high speed printing. In printing apparatus, if the paper or printing medium upon which the printed image is to appear is in motion relative to the character type faces at the instant of contact between the type face and paper or printing medium, a blurred image or imprint is produced. In low-speed printers, this problem presents no difficulties in that the paper or printing medium may have intermittent movement and thus be stopped during the actual contact time. Obviously, this intermittent motion is not feasible in a high-speed printer for, to obtain the desired speed, the motion of the paper or printing medium must be continuous. To obtain this continuous motion and still have a high quality printer, the printing system should provide for rolling or nonslip contact between the printing type face and the paper or printing medium. This nonslip contact is obtained, according to this invention, by maintaining zero velocity between the paper or printing medium and the type face.

-In the embodiments described above zero relative velocity is obtained by placing type faces 37 on the periphery of rotating printing drum 35. The tangential velocity of theprinting drum at its outermost surface is made equal to the linear velocity of printing tape 31. Thus, when type face 37 contacts printing tape 31, there is a rolling action of the type face on the printing tape but there is no relative movement between the two members. With such an arrangement, a high quality print is obtained without the necessity of stopping the printing tape during the printing operation. In the above system, the only time limitation is the rate at which type faces 37 can be brought into contact with the printing tape. For example, if each printing drum 35 has identical faces 37 equally spaced about its periphery and the drum is rotating at 100 revolutions per second, 3000 characters per second could be printed. 7

Increasing the number of type faces around the periphery of rotating drum and/or increasing the speed of rotation of the drum will increase the number of characters that may be printed per second. The primary factor limiting the speed of the present printing system is the speed at which the transducer or printing hammer may be actuated. Transducers are presently available having a contact time of millisecond and, even though the time of the complete operating cycle of the transducer is much longer, by preactuating the transducer the only time that need be considered is the contact time. For example, if the letter A were to be printed at a very high speed, the signal stored on the storage member could be so positioned with respect to ner would eliminate all but the actual transducer contact time from consideration in determining printing speed. Furthermore, if the same letter or numeral were to be printed in consecutive order, instead of actuating the transducer for each character the hammer could remain in contact with the printing tape for the time required for the printing of all the same consecutivecharacters and thus avoid the above limitation.

Although only one form of printing means has been described thus far, it will be apparent that other printing means may be employed in the printing system of this invention which will permit high-speed printing without blurring the characters. For example, there is shown in Fig. 7 another embodiment of a printing means according to this invention in which the printing means moves only during the printing time thereby maintaining zero relative velocity between the printing tape and the printing element.

- Referring now to Fig. 7, printing means 30 comprises a printing member 5-1 mounted for pivoted movement about a pivot point 52, the printing member having a central body portion 53 and an arm 54 integral with and extending from body portion 53. Central body portion 53 provides a seat 55 for a printing element 56 having a type face 58 at one end thereof. Printing element 56 is mounted for pivotal movement about a pivot point 57 in seat 55 from a first position 61 to a second position 62, the printing element being spring biased in the direction of first position 61 by a pressure spring 63.

' Positioned adjacent arm 54 of printing member 51 is an ing meansof "Fig. 7, the number of printing means. being determined by the number of difierent characters to be printed. When an appropriate electrical signal representing the character to be printed is impressed on exciting coil. 67, the magnetic field created attracts printing member 51 which, in turn, pivots about its 'pivot point 52 from its normally inoperative position to an operative position. In the operative position, type face 58 of printing element 56 engages printing tape 31 and causes an imprint of the character upon the tape. The movement of the printing tape in the direction of arrow 22 causes printing element 56 to rotate from first position 61 to second position 62 during the printing operation, continued rotation of the printing member after the imprint has been made on the printing tape being prohibited by the side wall of seat 55.

When the electrical signal is removed from exciting coil 67, spring 68 returns printing member 51 to its inoperative position and pressure spring 63 returns printing element 56 to first position 61 at which time the printing means is in a position where the operation may be repeated. The rotational movement of the printing element when in engagement with the printing tape enables the printing tape to be continuously moving without causing any blurring of the printed characters at high printing speeds.

What is claimed as new is:

l. A high-speed printer for printing different characters in space sequence on a printing medium in response to predetermined signals, respectively, said printing apparatus comprising: a plurality of printing elements longitudinally aligned adjacent the printing medium each element representing a diiferent character; a corresponding plurality of pivoted support members for mounting the respective printing elements, each of said support members providing a seat for its respective printing element to permit the printing element to rotate from a first position to a second position in the seat; first means for linearly moving the printing medium relative to said printing elements at a constant velocity; actuating means for engaging said printing elements with the printing medium in response to the predetermined signals, respectively, causing the printing element to rotate in the direction of motion of the printing medium from said first position to said second position at substantially zero velocity relative to the printing medium to effectuate the printing of the desired character; stop means for limiting the rotating movement of each printing element after the printing of the respective character has been completed; means for disengaging each printing element from said printing medium after the printing of the respective character has been completed; and means for returning each printing element from said second position to said first position.

2. A high-speed printer for printing different characters in space sequence on a printing medium in response to predetermined signals, respectively, said printer comprising: a plurality of pivoted printing members longitudinally aligned adjacent the printing medium each tion to a second position on said seat; first means for linearly moving the printing medium past said printing members at a constant velocity; actuating means for engaging said printing members with the printing medium to move said printing element in the direction of motion of the printing medium from said first position to said. second position at substantially zero velocity relative to the printing medium, thereby printing the character corresponding to the predetermined signal; stop means for limiting the movement of said printing element after the printing has been completed; means for disengaging said printing member from the printing medium; and means for returning said printing element to said first position.

. (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Carfoll Nov. 18, 1924 Priestley Sept. 27, 1927 5 Bull "July 3, 1928 Bryce Sept. 12, 1933 Knutsen Aug. 28, 1934