US3442206A

US3442206A - Apparatus for line printing

Info

Publication number: US3442206A
Application number: US639212A
Authority: US
Inventors: Tadashi Sugimoto
Original assignee: Fujitsu Ltd
Current assignee: Fujitsu Ltd
Priority date: 1966-05-19
Filing date: 1967-05-17
Publication date: 1969-05-06
Anticipated expiration: 1986-05-06
Also published as: DE1549726A1; GB1169784A

Description

May 6, 1969 Filed May 17, 1967 TADASHI SUGIMOTO APPARATUS FOR LINE PRINTING F/G.l

AREA 1 Sheet rrAs DRUM ii FT W l/AMMUPS /2 M 4 l /24 ms /2c 40 (04 J) 4) #4444152 4 CONTROL uA/lr l3 '-40COL 55 75C TADASH-l SUGIMOTO APPARATUS FOR LINE PRINTING R v f .3

kn nw mm l l I May 6, 1969 Filed May 17, 1967 y 5, 1969 TADASHI SUGIMOTO 3,442,206

APPARATUS FOR LINE PRINTING a Filed May 17, 1967 7 Sheet 3 of 8 COMPUTER 8/ TYPE C005 4M0 T/ME PULSE GENERATOR 57 May 6, 1969 TADASHI SUGIMOTO APPARATUS FOR LINE PRINTING y 14969 TADASHI susmo'ro 3,442,206

APPARATUS FOR LINE PRINTING Filed May 17, I967 Sheet 6 of a y 1969 TADASHI suemo'ro 3,442,206

APPARATUS FOR LINE PRINTING Sheet Filed May 17, 1967 Q m w v m m N m M Q m ND M Q h w m x h A 0 Q m m w m N J m WnNaW o "a wnmwom Q vmr o mmuom wmwmomom TNYQ QWQQQQ United States Patent U.S. Cl. 101--93 3 Claims ABSTRACT OF THE DISCLOSURE A plurality of printing hammers of line printing apparatus are successively operated in groups to print groups of columns in succession. The number of columns in each of the groups is less than the total number of columns and is the same in each of the groups.

Description of the invention The present invention relates to line printing. More particularly, the invention relates to a method and apparatus for line printing.

Line printers of known type utilize printing hammers and hammer actuating magnets. The hammer actuating magnets are controlled in operation, actuation or energization to control the operation of the hammers and thereby to control the printing. It is often desirable to increase the printing speed of the line printer, and there have been many different types of printing apparatus and printing methods. As the printing speed is increased and the performance enhanced, the cost of the apparatus increases. There are, however, small-sized electronic computers which utilize in their inputs and/ or outputs smallsized low speed printers. The line printers utilized with the small-sized computers must be of low cost in order to raise the ratio of the performance of the equipment relative to its cost.

The principal object of the present invention is to provide a new and improved method and apparatus for line printing. The method and apparatus of the present invention for line printing are suitable for operation with smallsized computers. The apparatus of the present invention for line printing is of small size and of low cost and operates at low speed. The apparatus of the present invention for line printing is efficient, effective and reliable in operation. The apparatus of the present invention for line printing utilizes conventional known components and conventional known line printing equipment.

In accordance with the present invention, the method of line printing a plurality of columns comprises printing groups of columns in succession. The number of columns in each of the groups of columns is less than the total number of the plurality of columns. The number of columns in each of the groups of columns is the same. The groups of columns are printed in a line on a recording medium by printing the groups of columns in succession and upon completion of the printing of the groups of columns the recording medium is fed to its next line. The groups of columns are printed in a line on a recordingmedium by printing only determined ones of the groups of columns to be printed, bypassing the others of the groups of columns not to be printed and feeding the recording medium to its next line at free points of time.

In accordance with the present invention, line printing apparatus comprises printing apparatus for printing a plurality of columns. The printing means includes a plurality of printing hammers. Hammer control apparatus controls the operation of the printing apparatus to suc- 3,442,206 Patented May 6, 1969 cessively operate the plurality of printnig hammers in groups to print groups of columns in succession.

The hammer control apparatus comprises a plurality of hammer-controlling electromagnets each controlling a corresponding one of the printing hammers. Switches are interposed between the electromagnets and a power supply source for selectively switching one group of electromagnets at a time to the power supply source. Each group of electromagnets is the same as each group of corresponding printing hammers. The switches are a plurality of semiconductor controlled rectifiers and the number of semiconductor controlled rectifiers is the same as the number of the groups.

In order that the present invention may be readily carried into effect, it will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic block diagram illustrating the principle of operation of the apparatus of the present invention and the method of the present invention;

FIG. 2 is a circuit diagram illustrating the operation of the apparatus of the present invention and the method of the present invention;

FIG. 3 is a block diagram of an embodiment of the apparatus of the present invention;

FIGS. 4A and 4B are time charts illustrating the operation of the embodiment of FIG. 3;

FIG. 5 is a block diagram of a modification of the apparatus of the present invention;

FIGS. 6A and 6B are time charts illustrating the operation of the modification of FIG. 5;

FIG. 7 is a schematic side view of an embodiment of a line printer;

FIG. 8 is a perspective view of a type wheel;

FIG. 9 is a developed view of the type surface of a type wheel; and

FIG. 10 is an illustration of the printed data on the printing paper.

FIG. 1 illustrates the principle of operation of the apparatus of the present invention. The components of FIG. 1 may comprise any suitable components known in the art for performing the indicated functions. A type drum 11 is rotatably mounted and may comprise, for example, 120 columns. Print hammers 12 are mounted in operative proximity with the type drum 11 and function to print 120 columns in a known manner.

A hammer control unit 13 is electrically connected to the electromagnets of the print hammers 12. The hammer control unit 13 functions to operate, actuate or energize 40 print hammers at a time to thereby print 40 columns. A shift register 14 is electrically connected to the hammer control unit 13 and functions to store 40 bits of control data or information.

In the apparatus of FIG. 1, although the type drum 11 is divided into three

equal areas

1, 2 and 3, each being a cylindrical surface area equal to one-third the cylindrical surface area of said drum, said drum may be divided into any suitable number n of equal cylindrical surface areas. The number of print hammers 12, and therefore columns printed under the control of the hammer control unit 13, controlled by said hammer control unit, corresponds to the number of equal areas into which the drum 11 is divided. The shaft register 14 stores a number of bits of control data equal to the number of columns printed at one time under the control of the hammer control unit 13.

In accordance with the present invention, each group of hammer-controlling electromagnets is driven or controlled in succession by the hammer control unit 13. Thus, in accordance with the method of the present invention, a number of columns equal to the total number of columns of the type drum 11 divided by n, is first printed by the hammer control unit 13, the next succeeding equal number of columns is next printed under control of the hammer control unit 13, and so on, until all the columns of the type drum are printed. For purposes of illustration, the area of the type drum 11 is divided into three equal areas, so that n:3, and the 120 columns of said type drum are divided into three equal groups of 40 columns each. The 40 columns of area 1 of the type drum 11 are first printed under the control of the hammer control unit 13, the 40 columns of area 2 of said type drum are then printed under the control of said hammer control unit, and the 40 columns of area 3 of said type drum are then printed under the control of said hammer control unit. During each printing of the columns of an area of th type drum 11, said type drum is rotated or driven in a suitable manner by suitable known apparatus, not shown in the figures.

During the printing operation, the printing paper or recording medium, not shown in FIG. 1, which is interposed between the print hammers 12 and the type drum 11, remains in the same position, whereas said type drum rotates three times for the printing of a single line. In order to print the 40 columns of area 1 of the type drum 1 a switch 15A is closed, either manually or automatically, to close a circuit between the hammer control unit 13, the first group 12A of 40 print hammers and a source of voltage E. In order to print the 40 columns of area 2 of the type drum 11, a switch 15B is closed, either manually or automatically, to close a circuit between the hammer control unit 13, the second group 12B of 40 print hammers and the source of voltage E. In order to print the 40 columns of area 3 of the type drum 11, a switch 150 is closed, either manually or automatically, to close a circuit between the hammer control unit 13, the third group 120 of 40 print hammer and the source of voltage E. Only one of the switches 15A, 15B and 150 is closed at a time, and said switches are operated in sequence.

FIG. 2 illustrates the operation of the hammer-controlling electromagnets under the control of the hammer control unit 13. In FIG. 2, the hammer-controlling electromagnets are not all illustrated, but are indicated only by the first and last of each group of said electromagnets. Thus, in FIG. 2, the hammer-controlling electromagnets of the first of the three groups of said electromagnets are represented by the first electromagnet 16-1 and the last of said electromagnets 16-h. In the present example, I: equals 40. The hammer-controlling electromagnets of the second of the three groups of said electromagnets are represented by one first electromagnet 17-1 and the last of said electromagnets 17-h. The hammer-controlling electromagnets of the third of the three groups of said electromagnets are represented by the first electromagnet 18-1 and the last of said electromagnets 18-h.

The hammer control unit 13 is indicated principally in block form. However, a first control transistor 19-1 and a last control transistor 19-h are shown as included in the hammer control unit 13 in order to enhance the description of the operation of said unit. Each of the control transistors 19-1 to 19-h of the hammer control unit 13 controls a corresponding one of the hammer-controlling electromagnets of each of the n groups of said electromagnets. Thus, the control transistor 19-1 is connected in series with the first hammer-controlling electromagnet 16-1, 17-1 and 18-1 of each of the three groups of said electromagnets. The control transistor 19-h is connected in series with the last hammer-controlling electromagnets 16-h, 17-h and 18-h of each of the three groups of said electromagnets.

The series connection of the corresponding control transistor of the hammer control unit 13 and the corresponding hammer-controlling electromagnets is through corresponding diodes which prevent a current flow in th opposite direction. Thus, the collector electrode of th control transistor 19-1 is connected in common to one end of the winding of each of the electromagnets 16-1,

4 17-1 and 18-1 via a common lead 21, leads 22, 23 and 24 and

corresponding diodes

25, 26 and 27. The diode 25 is connected in the lead 22 with its anode connected to the common lead 21 and with its cathode connected to the aforementioned end of the winding of the electromagnet 16-1. The diode 26 is connected in the lead 23 with its anode connected to the common lead 21 and with its cathode connected to the aforementioned end of the winding of the electromagnet 17-1. The diode 27 is connected in the lead 24 with its anode connected to the common lead 21 and with its cathode connected to the aforementioned end of the winding of the electromagnet 18-1. The emitter electrode of the control transistor 19-1 is connected to ground via a lead 28.

The collector electrode of the control transistor 19-h is connected in common to one end of the winding of each of the electromagnets 16-h, 17-h and 18-h via a common lead 29, leads 31, 32 and 33 and

corresponding diodes

34, and 36. The diode 34 is connected in the lead 31 with its anode connected to the common lead 29 and with its cathode connected to the aforementioned end of the winding of the electromagnet 16-h. The diode 35 iS connected in the lead 32 with its anode connected to the common lead 29 and with its cathode connected to the aforementioned end of the winding of the electromagnet 17-h. The diode 36 is connected in the lead 33 with its anode connected to the common lead 29 and with its cathode connected to the aforementioned end of the winding of the electromagnet 18-h. The emitter electrode of the control transitsor 19-h is connected to ground via a lead 37.

The emitter electrode of each of the 40 control transistors 19-1 to 19-h of the hammer control unit 13 is connected to one terminal of an electrical power supply source E via a common ground line 38 and a lead 39. The other terminal of the power source E is connected in common to the cathode of each of three semiconductor controlled rectifiers or

SCRs

41A, 41B and 41C via a common lead 42 and leads 43, 44 and 45, respectively. The anode of the first SCR 41A is connected in common to the other end of the winding of each of the hammer-controlling electromagnets 16-1 to 16-h of the first group of said electromagnets via a common lead 46 and branch leads 47-1 to 17-11, respectively. The anode of the second SCR 41B is connected in common to the other end of the winding of each of the hammer-controlling electromagnets 17-1 to 17-h of the second group of said electromagnets via a common lead 48 and branch leads 49-1 to 49-h, respectively. The anode of the third SCR 410 is connected in common to the other end of the winding of each of the hammer-controlling electromagnets 18-1 to 18-h of the third group of said electromagnets via a com mon lead 51 and branch leads 52-1 to 52-h, respectively.

Each of the hammer-controlling electromagnets is shunted by a clamping diode. Thus, a clamping diode 53 is shunted across the hammer-controlling electromagnet 16' 1. A clamping diode 54 is shunted across the hammer-com trolling electromagnet 17-1. A clamping diode 55 is shunted across the hammer-controlling electromagnet 18-1. A clamping diode 56 is shunted across the hammer-controlling electromagnet 16-h. A clamping diode 57 is shunted across the hammer-controlling electromagnet 17-Iz. A clamping =diode 58 is shunted across the hammer-controlling electromagnet 18-h.

Each of the first, second and

third SCRs

41A, 41B and 51C may comprise any suitable SCR known in the art, such as, for example, those described in considerable detail in the Silicon Controlled Rectifier Manual, third edition, 1964, General Electric Company, Auburn, N.Y. Each SCR includes a gate or control electrode which is utilized to control the conductive condition of such SCR.

A switching control transistor 59 is connected in the common ground line 38. The emitter electrode of the switching control transistor 59 is connected to the ground terminal of the electrical power source E and the collector electrode of said switching control transistor is connected in common via a lead 61, a control resistor 62, and leads 63, 64 and 65, to the anodes of

coupling diodes

66A, 66B and 66C, respectively.

The cathode of the first coupling diode 66A is connected to the lead 46 and to the anode of the first SCR 41A via a lead 67. The cathode of the second coupling diode 66B is connected to the lead 48 and to the anode of the second SCR 41B via a lead 68. The cathode of the third coupling diode 66C is connected to the lead 51 and to the anode of the third SCR 41C via a lead 69.

A switching control unit 71 controls the conductive condition of the switching control transistor 59 and of each of the

SCRs

41A, 41B and 41C. The switching control unit 71 is thus connected to and provides a control signal to the base electrode of the switching control transistor 59 via a lead 72 and to the control electrodeof each of the

SCRs

41A, 41B and 41C via leads 70A, 70B and 70C, respectively.

A computer 81 (FIG. 3) is connected to an input of the switching control unit 71 via a lead 99 (FIG. 3) and to an input of a collator 95 (FIG. 3) via a lead 97 (FIG. 3). The connection and relation of the computer 81, the switching control unit 71 and the collator 95 are described with reference to FIG. 3. The output of the collator is connected to an input of the shift register 14 (FIG. 1) via a lead 103 (FIG. 3). The shift register 14 is connected to and provides a control signal of the base electrode of each of the control transistors 19-1 to 19-h via a corresponding one of leads 73-1 to 73-11, respectively.

The printing operation is controlled either manuallyor automatically such as, for example, via prerecorded program, through the computer 81 and the switching control unit 71 and the collator 95 and shift register 14. Although each of the SCRs or

thyristors

41A, 41B and 41C is switched to its conductive or ON condition by a sutficient current in its control electrode, the potential of its anode must be positive and higher in magnitude than that of its cathode. Each of the

SCRs

41A, 41B and 41C is switched to its non-conductive or OFF condition by decreasing the potential of the anode to a magnitude below that of the cathode.

The switching control unit 71, under the control of the computer 81, first switches the switching control transistor 59 to its conductive or ON condition. When the switching control transistor 59 is in its conductive condition, it maintains the potential of the anodes of the

SCRs

41A, 41B and 41C positive and at a higher magnitude than that of the cathodes thereof and said SCRs can be switched ON by suflicient current supplied to the control electrodes thereof. When the switching control transistor 59 is in its non-conductive condition, the potential of the anodes of the

SCRs

41A, 41B and 41C becomes equal to that of the cathodes thereof and said SCRs cannot be switched ON, but are, rather switched off.

As illustrated in FIG. 4A, the computer 81 supplies, via the switching control unit 71 and the

leads

70A, 70B and 70C, successive switching signals to the control electrodes of the

CSRs

41A, 41B and 41C. When a switching signal is supplied to the control electrode of the first SCR 41A, it provides sufiicient current to the control electrode of said first SCR to switch said SCR to its conductive or ON condition. The computer 81, via the collator 95 and the shift register 14, then switches the control transistors 19-1 to 19-h to their conductive or ON condition, thereby closing an energizing circuit to the power source E for the hammer-controlling electromagnets 16-1 to 16-h through the first SCR 41A. This operation is then repeated for each of the second and third areas of the type drum 11 (FIG. 1) by the switching of the second and third SCRs 41B and 41C to their conductive conditions.

When the printing of the first area of the type drum 11 is completed, the second SCR 41B is switched to its conductive condition in the aforedescribed manner and the hammer-controlling electromagnets 17-1 to 17-h of the second group of said electromagnets are energized and cause the printing of the second area of the type drum 11. Since only one of the three SCRs is energized or fired at one time, only one of said SCRs is in its conductive condition at one time, so that only one of the first, second and

third areas

1, 2 and 3 is printed at one time. Upon completion of the second area of the type drum 11, the third SCR 41C is switched to its conductive condition and energizes the hammer-controlling electromagnets 18-1 to 18-h in the aforedescribed manner to print the third area of said type drum.

In the embodiment of the apparatus of FIG. 3, a computer 81 is directly connected to the line printer 82 without the interposition of a butter memory unit. In the modification of FIG. 5, however, a buffer memory unit is interposed between the computer 81 and the line printer. The same components of FIGS. 3 and 5 are indicated by the same reference numerals therein. FIGS 4A and 4B are time charts illustrating the operation of the embodiment of FIG. 3.

In FIG. 3, the line printer 82 comprises the type drum 11 (FIG. 1), the print hammers 12 (FIG. I), and the hammer-controlling elec'tromagnets 83 which include the electromagnets 16-1 to 16-h, 17-1 to 17-h and 18-1 to 18-11 (FIG. 2). The line printer 82 also includes the hammer control unit 13 and the shift register 14 (FIG. 1). A recording medium or printing paper 84 is interposed between the type drum 11 and the print hammers 12 and is driven or moved by any suitable means (not shown in the figures). The line printer also includes a diode circuit 85 which includes the various diodes such as, for eX- ample, the

diodes

25, 26, 27, 34, 35 and 36 (FIG. 2) and an SCR circuit 86 which includes the first, second and

third SCRs

41A, 41B and 41C (FIG. 2). The switching control unit 71 (FIG. 2) is connected to the SCR circuit 86.

A type code and time pulse generator 87 is coupled to the type drum 11 for rotation with said type drum. The output or time pulses of the generator 87 are supplied to the input of a time pulse detector 88 via a lead 89 and to the input of an amplifier 91 via the lead 89 and a lead 92. The output of the amplifier 91 is supplied to the input of a type code register 93 via a lead 94 and the output of said register is supplied to an input of a collator 95 via a lead 96. Another input of the collator 95 is supplied, via a lead 97, by the computer 81.

The output of the detector 88 is applied to an input of the switching control unit 71 via a lead 98. Another input of the switching control unit 71 is supplied by the computer 81 via a lead 99. An output of the switching control unit 71 is connected to the hammer control unit 13 via a lead 101 and to an input of the shift register 14 via the lead 101 and a lead 102. The output of the collator 95 is supplied to another input of the shift register 14 via a lead 103. The output of the shift register 14 is supplied to an input of the hammer control unit 13 via a lead 104. The output of the hammer control unit 13 is supplied via a lead 105 and the diode circuit 85 to the hammer-controlling electromagnets 83. The diode circuit 85 is connected to an output of the switching control unit 71 via a lead 106, the SCR circuit 86 and a lead 107.

FIGS. 4A and 4B illustrate the basic printing operation of the apparatus of the embodiment of FIG. 3. In each of FIGS. 4A and 4B, each of the line segments extends in the direction of the abscissa, which represents time. FIG. 4A illustrates the printing of one line having columns.

There are four basic orders involved in the printing of one line of 120 columns, four basic orders include three printing orders P1, P2 and P3 for the

corresponding areas

1, 2 and 3 of the type drum 11 (FIG. 1), respectively. The fourth basic order is the feeding order F1 for the recording medium or paper 84 (FIG. 3).

as illustrated in FIG. 4A. The

The computer 81 provides the first printing order P1 for the printing of the first area 1 of the type drum 11 (FIG. 1) in the switching control unit 71 via the lead 99 (FIG. 3). This switches the first SCR 41A of FIG. 2 in the SCR circuit 86 (FIG. 3) to its conductive condition. The initial control signal supplied by the computer 81 simultaneously starts the printing cycle R1 and said computer provides the printing information.

The type code corresponding to the type on the type drum 11 (FIG. 3) is indicated by the type code and time pulse generator 87 of FIG. 3 and is stored in the type code register 93 after amplification by the amplifier 91 (FIG. '3). The type code stored in the register 93 is collated in the collator 95 with the printing information supplied by the computer 81 via the lead 97 and the result of the collation is stored in the shift register 14 (FIG. 3). Upon the completion of the collation of 40 columns the hammer control unit 13 is triggered by the next time pulse from the type code and time pulse generator 87 and the result of the collation of the 40 columns is printed. The aforedescribed operation completes the printing of one letter. The printing of the 40 columns of area 1 of the type drum 11 (FIG. 1) is completed when all of the 64 letters of the type drum (FIG. 4A) have been printed by the aforedescribed operation commencing with the initiation of the transfer of printing information and concluding with the printing.

When the first area 1 of the type drum 11 (FIG. 1) has been completely printed, the computer 81 (FIG. 3) provides the second printing order P2 (FIG. 4A) for the rinting of the second area 2 of said type drum. The second SCR 41B (FIG. 2) of the SCR circuit 86 of FIG. 3 is then switched to its conductive condition, the first SCR 41A having been switched to its non-conductive condition upon the supply of the second printing order P2 to the switching control unit 71 (FIG. 3). The second area 2 of the type drum 11 (FIG. 1) is then printed in the same manner as the first area 1 of said type dru-m. Upon completion of the printing of the area 2 of the type drum 11, the third area 3 of said type drum (FIG 1) is then printed in the same manner as the

areas

1 and 2, under the control of the third printing order P3 from the computer 81.

When the printing of the third area 3 of the type drum 11 (FIG. 1) is completed, the printing of a single line is completed. The computer 81 (FIG. 3) then provides the paper feeding order F1 and the paper is fed or moved to its next line position by suitable apparatus (not shown in the figures). The printing cycle for one line is completed upon the completion of the feeding or moving of the printing paper 84 (FIG. 3) in response to the paper feeding order F1.

The time chart of FIG. 4B illustrates another arrangement of printing orders in the apparatus of FIG. 3. In the arrangement of printing orders illustrated in FIG. 4B, the computer 81 provides the first printing order P1. The first printing order P1 is then followed by paper feeding orders F1 and F2 which are followed by a repetition of the first printing order P1. After the completion of the printing R1 of the first area 1 of the type drum 11 (FIG. 1), a third paper feeding order F3 is supplied. The third paper feeding order F3 is followed by the second printing order P2.

The basic printing cycle of the apparatus of FIG. 3, illustrated in FIG. 4B, avoids unnecessary printing time in the event of slippage in the printing of the first area 1 of the type drum 11 since it involves feeding the paper twice (F1 and F2) so that said paper is moved two lines, print ing the first area 1 (R1) and feeding the paper by one line (F3) and printing the second area 2 (R2), and so on, as shown in FIG. 4B. In a conventional line printing operation, where the printing and feeding are controlled by a single order, the printing time for the second and

third areas

2 and 3 of the type drum 11 (FIG. 1) is wasted if only the first area 1 is actually printed. Furthermore,

in such conventional line printer operation, the structure of the line printer is complex. In accordance with the method of the present invention, there are four independent orders which need not be in any particular succession with relation to each other, so that areas which are not to be printed are not ordered to be printed by corresponding printing orders. Thus, the next succeeding printing order is provided for an area to be printed, so that there is no printing time wasted and high speed processing is accomplished.

In the modification of FIG. 5, a buffer memory in the form of a core memory, or other suitable memory device, is included in the line printer apparatus. Thus, in the modification of FIG. 5, an output of the switching control unit 71 is connected to the input of a core memory 111 via a lead 112, an inhibitor 113 and a lead 114. The output of the core memory 111 is connected to the input of a shift register 115 via a lead 116. An output of the shift register 115 is connected to a second input of the collator via a lead 117 and to an input of the switching control unit 71 via the lead 117 and a lead 118.

As shown in FIG. 6A, a complete printing cycle R is accomplished by three rotations of the type drum 11 (FIG. 5). The printing information is provided by the computer 81 and the first printing order for printing the first area 11 of the type drum 11 (FIG. 1) is supplied by said computer. Both the printing information and the printing orders are supplied by the computer 81 to the switching control unit 71 and are stored in the core memory 111. When the printing information for one column has been completely transferred to the core memory 111, the line printer is in effect disconnected from the computer 81. When the first printing order P1 has been provided, the line printer initiates the printing cycle R (FIG. 6A). The line printer thus first provides the first printing subcycle S1 by printing the first area 1 of the type drum 11 (FIG. 6A), that is, the stored contents of the core memory 111 are read out via the shift register .115 and are collated by the collator 95 with the type codes and are printed for the first 40 columns after the typing of the 64 letters. The line printer then provides the second printing subcycle S2 (FIG. 6A) by printing the second area 2 of the type drum 11. Upon completion of the second printing subcycle S2, the line printer provides the third printing subcycle S3 by printing the third area 3 of the type drum 11 (FIG. 1).

The printing of the three areas of the type drum 11 (FIG. 1) is completed after said type drum has rotated three times. After three rotations, the printing cycle R is thus completed. The line printer then provides the paper feeding cycle F (FIG. 6A), and the recording medium or printing paper 84 (FIG. 5) is fed or moved one line for the transfer of the next succeeding printing information under the control of the second printing order P2 (FIG. 6A). The buffer memory 111 of the modification of FIG. 5 thus permits the printing of the three areas or groups of columns of the type drum 11 to follow any desired sequence or pattern such as, for example, the conventional printing cycle of a line printer. If the conventional pr nting cycle is followed by the apparatus of FIG. 5, the printing time is three times the duration of the printing time of a line printer following the conventional printing cycle in which a single line is printed by a single rotation of the type drum.

The extra printing time illustrated in FIG. 6A is eliminated when the apparatus of FIG. 5 is operated in accordance with the time chart of FIG. 6B. In FIG. 6B, the end of the printing cycle R is indicated due to supervision of the printing information independent of the rotation of the type drum. The supervision of the printing information may be provided by signal bits, flag bits or other indicating or identifying signals, symbolically represented in FIG. 5 by cross-hatched strips on the core memory 111 and the shift register 115. One signal bit is added to the core memory 111 for each column. The signal bits permit the supervision of the printing information and increase the printing speed by preventing the waste of printing time. The signal or flag bit and its application is described in Japanese patent application Ser. No. Tokugansho 39-27124, filed May 14, 1964.

The computer 81 supplies the first printing order P1 (FIG. 6B) to the switching control unit 71 (FIG. 5) and the printing information is also supplied to said switching control unit. At the same time a signal is recorded as the flag bit of the column to be printed and a 1 signal is recorded in the other columns. The line printer then provides the entire printing cycle R by providing the printing subcycles S1, S2 and S3 (FIG. 6B) in sequence.

Upon the provision of the first subcycle S1, the first area 1, of 40 columns, of the type drum 11 (FIG. 1) is read out of the core memory 111 and is printed. The con tents of the first area are read out of the core memory 111 and are collated with the type code by the collator 95, so that the columns of the first area are printed in accordance with the type code. The flag bit of the column printed is changed from 1 to 0 as the printing of each column is completed. Each time the information stored in the core memory 111 is read out, the flag bit is detected, and when all the flag bits of the group or area are detected as being 0, the first printing subcycle S1 is completed and the second printing subcycle S2 is initiated. The second and third printing subcycles S2 and S3 then follow in the same manner as the first printing subcycle S1 (FIG. 6B).

The signal bit or flag bit control system utilized in conjunction with the core memory 111 thus completes a single printing subcycle within one rotation of the type drum 11 (FIG. 5), and when there is no printing information for an area, the only time utilized is that for reading out 40 columns of the core memory 111, which time is approximately 100 microseconds. The printing speed of the apparatus of FIG. 5 illustrated in FIG. 6B is thus twice that illustrated in FIG. 6A.

The flag bit or signal bit system for indicating the end of each printing subcycle of the printing cycle is described as one possible means for such indication. In actuality, any suitable detecting arrangement may be utilized such as, for example, counting systems or the like. Thus, the number of columns containing printing data or information may be counted in advance when the information is transferred to the switching control unit 71 (FIG. 5) and the number of columns printed may be counted each time a column is printed. The printing cycle for the printing of all the columns is then indicated as completed when the number of columns actually printed is the same as the number of columns counted in advance.

FIG. 7 shows a line printer for a hammer which may be utilized as each hammer of the apparatus of the present invention.

FIG. 8 shows a type wheel which may be utilized as the type wheel of the apparatus of the present invention.

FIG. 9 illustrates the type surface of a type wheel which may be utilized as the type wheel of the apparatus of the present invention.

FIG. 10 illustrates the data printed by the apparatus of the present invention on the printing paper of said apparatus. In FIG. 10, the horizontal spaces indicate thirty columns divided into three groups or areas of ten each. The vertical spaces indicate the type printing characters or numbers of the type wheel and comprise the numerals 0 to 9. The thirty columns are completely printed by the revolution of the type wheel three times.

FIGS. 7, 8 and 9 are FIGS. 1, 2 and 3, respectively, of United States Patent No. 3,322,063, issued May 30, 1967.

While the invention has been described by means of specific examples and in specific embodiments, I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. Line printing apparatus, comprising printing means for printing a plurality of columns, said printing means including a plurality of printing hammers, hammer control means for controlling the operation of said printing means to successively operate said plurality of printing hammers in groups to print groups of columns in succession, the number of columns in each of the groups of columns being less than the total number of said plurality of columns, said hammer control means comprising a plurality of hammer-controlling electromagnets each controlling a corresponding one of said printing hammers, electrical power supply means and switching means interposed between said electromagnets and said power supply means for selectively switching one group of electromagnets at a time to said power supply means, each group of electromagnets being the same as each group of corresponding printing hammers.

2. Line printing apparatus as claimed in claim 1, wherein said switching means comprises a plurality of semiconductor controlled rectifiers interposed between said electromagnets and said power supply means for selectively switching one group of electromagnets at a time to said power supply means, and the number of said semiconductor controlled rectifiers is the same as the number of said groups.

3, Line printing apparatus as claimed] in claim 2, Wherein said hammer control means comprises switching control means connected to said semiconductor controlled rectifiers for controlling the conductive condition of each thereof.

References Cited UNITED STATES PATENTS 2,080,649 5/1937 Breiting 101-96 2,770,188 11/1956 Nolan 101-93 2,787,953 4/1957 Sobisch et al 101-93 2,831,424 4/1958 MacDonald 101-111 X 3,007,399 11/1961 Sasaki et al 101-93 3,064,561 11/1962 Maudit 101-93 3,157,115 11/1964 West et a1. 101-93 3,175,486 3/1965 Athens et a1. 101-93 3,247,788 4/ 1966 Wilkins et a1. 101-93 WILLIAM B. PENN, Primary Examiner.