US3232229A

US3232229A - Ink ribbon feed and reverse mechanism

Info

Publication number: US3232229A
Application number: US362047A
Authority: US
Inventors: Hilding A Anderson
Original assignee: SCM Corp
Current assignee: SCM Corp
Priority date: 1961-03-30
Filing date: 1964-04-23
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01
Also published as: GB999372A; US3305707A; GB999373A; GB999371A; GB999375A; GB999374A

Description

Feb. 1, 1966 H. A. ANDERSON INK RIBBON FEED AND REVERSE MECHANISM 5 Sheets-Sheet 1 Original Filed March 30, 1961 Form wzo 0mm". :ommE

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m WEPZDOQ CD325 INVENTOR. Hilding A.Anderson eh 1, 1966 H. A. ANDERSON 3,

INK RIBBON FEED AND REVERSE MECHANISM Original Filed March 30, 1961 5 Sheets-Sheet 2 INVENTOR Hilding A.Anderson BYJM pddgf ATTOR Feb 1, 1966 H. A. ANDERSON 3,232,229

INK RIBBON FEED AND REVERSE MECHANISM Original F iled March 30,' 1961 s Sheets-Sheet 5 INVENTOR Hilding A. Anderson ATTORNEYS 5 Sheets-Sheet 4 Feb. 1, 1966 H. A. ANDERSON INK RIBBON FEED AND REVERSE MECHANISM Original Filed March 30, 1961 h x mm l m x9 x m m|-- 4 m O9 09 x? x8 v5 V5 E Y B vam I w Eda 4 n n l 2:: ow om, 556mm 8| I $55 n u amma -w+ xmm xmm xmn 51w mzo vw SE zomma m I II moon W v. 29% MN I T V5; c9 09 iv flfi m m wfi 2891 ON] 556% ON] United States Patent 3,232,229 INK RKBBUN FEED AND REVERSE MECHANISM Hilding A. Anderson, Lake Zurich, Ill., assignor to SCM gorporation, New York, N.Y., a corporation of New ork Original application Mar. 30, 1961, Ser. No. 103,183, new Patent No. 3,131,627. Divided and this application Apr. 23, 1964, Ser. No. 362,047

2 Claims. (Cl. 101-336) This invention relates to an ink ribbon feed and reverse mechanism and its control equipment and is particularly related to use of such ink ribbon equipment in combination with a high speed printing apparatus designed to print a message, coded or otherwise, on a paper tape, said message being received as electrical code signals which originate in a telegraphic or data processing system or other similar telegraphic mediums. This application is a division of co-pending US. application Serial No. 103,183, filed March 30, 1961, now Patent No. 3,131,627 for High Speed Serial Printer.

The invention in the aforenoted parent application uses, as a basic principle of operation, electronic selection and actuation of a print hammer which is aligned to print a serial message on a tape from a row of characters positioned around the periphery of a continuously rotating typewheel. In recent years, as the need for higher speed printers has become urgent, printing on the fly or printing without stopping the rotation of the typewheel has come into prominence, particularly in connection with printing computor output information delivered at high output rates. The present invention is herein disclosed in combination with an exemplary high speed printer utilizing an electromagnetic impulse transducer form of typewheel position detector where a pulse is generated for each typewheel position starting from an indexing point (or points) and the pulse counts compared with an incoming code signal in an electronic counter to determine the typewheel position. Print hammer actuation is then controlled relative to instantaneous shaft position to record any desired character while the typewheel is rotating. The required shaft position impulses may be obtained in other known Ways such as by photocells with a perforated clock disc and a light source. The control mode of the ink ribbon feed mechanism, of the present invention, in other Words, stepping of the feed mechanism by electronic control which by means of electronic circuitry reduces the rate of ink ribbon teed steps relative to machine rate of operation, could also be applicable to relatively low speed printers where shaft position impulses can be obtained by brushes and commutators, although the advantages of the invention are primarily realized in combination with high speed printers.

Very briefly, the tape printer in which the present invention is disclosed uses two rows of type characters, each type row having its associated print hammer, a dual tape stepping mechanism which is associated, through control apparatus, for specific ditierent modes of operation with each specific print hammer and an ink ribbon which feeds between the tape and a print wheel. Whichever row of characters includes the character selected for printing, printing will occur at the next serial print position on the tape. This is accomplished by utilizing two basic modes of machine operation, termed PRINT FIRST- THEN SPACE (for characters in typewheel row #1) and SPACE FIRSTTHEN PRiNT (for characters in typewheel row #2). The appropriate mode of operation is automatically determined by the machine upon receipt of the appropriate character signal (the signal being coded according to desired typewheel row). Two additional modes of operation, essentially functional, are also pro- 3,232,229 Patented Feb. 1, I966 ice vided: a SPACE-NO PRINT mode and a MANUAL TAPE FEED-OUT mode. For convenience in circuitry, ink ribbon feed is actuated electronically during all modes of operation but its rate is only one-half that of code signal reception by the printer.

Accordingly, a principal object of this invention resides in the provision of a novel, electronically controlled and powered ink ribbon drive mechanism in an electromechanical tape printer capable of operating at very high speeds.

Another object resides in the provision of a typewheel serial printer having a complete ink ribbon feeding and reversing mechanism with a novel electronic control and power circuit correlated with printer operation and reducing the rate of drive of the ink ribbon mechanism relative to that of printing and spacing operations, thus effectively reducing ink ribbon wear and increasing the speed and efficiency of printer operation.

A further object resides in providing in combination with a high-speed electronic serial printing tape printer with stepping tape feed mechanism, a novel electronic ribbon feed control correlated with the electronic print and space control.

Further objects and advantages of the invention will be apparent from the following description and the appended claims taken in conjunction with the accompanying drawings showing a preferred embodiment thereof, in which:

FIGURE 1 is a block diagram of a printer with electronic controls and an electronically controlled ribbon feed and reverse mechanism in accord with the present invention, the electronic control and mechanical components being illustrated by schematic symbols;

FIGURE 2 is a fragmentary perspective View of a printer, in which support structure and control circuitry are deleted, illustrating the primary mechanical components, the typewheel shaft position detector clocks with transducer members and the solenoids which operate the mechanical print hammer, tape feed and ribbon feed components;

FIGURE 3 is an enlarged top plan view of the mechanical components of the ink ribbon feed and reverse apparatus;

FIGURE 4 is a perspective view of the ink ribbon feed and reverse apparatus seen in FIGURE 3;

FIGURE 5 is a detailed partially sectioned view of the right-hand mechanism of the ink ribbon feed and reverse apparatus of FIGURE 3; and

FIGURES 6 and 7 taken as a unit will provide a detailed circuit diagram of an exemplary transistorized printer circuit for control of the ink ribbon drive in accord with the present invention. The detailed components of this circuit diagram correspond to portions of the symbolized schematic diagram of the electronic components in FIGURE 1 pertaining to the ink ribbon controls, and representative symbolized components are included with the individual FIGURES 6A and 7A as subscript figures of FIGURES 6 and 7 to enable a rapid correlation of that portion of the detailed circuit with the overall symbolized circuit of FIGURE 1. For example, FIGURE 6A is the symbol for the ribbon feed one-shot, current driver and solenoid circuits detailed in FIGURE 6 and FIGURE 7A is the symbol for the detailed ribbon feed divide-by-two circuit shown in FIGURE 7.

The following description is of a specific electronic high speed printer utilizing the ink ribbon control and power circuitry for feed drive in accordance with the present invention. It is to be understood that the invention is not restricted to be exemplary transistorized circuit components illustrated in FIGURES 1, 6 and 7. Other types of circuit components and devices may be employed in the ink ribbon control and driving circuit, for example, vacuum tube switching circuits may be used. The illus- 3 trated transistorized circuit, however, does represent an operative and preferred construction.

The complete circuit combination and some subcombination circuits are novel and are fully described in the aforenoted parent application, now Patent No. 3,131,627. Inasmuch as the various components of the detailed circuit of FIGURES 6 and 7, such as the and gates, delays, one-shots, current drivers, counters, registers, etc., are known, they will not be described in detail except for the following aspects. These or equivalent circuits, of course, could utilize electron tubes, but to conserve space, power, avoid heat and obtain long life of operating components, the transistorized circuits are preferable. All of the depicted transistors in FIGURES 6 and 7 are 2N1372 unless otherwise indicated on the figures. All diodes are Germanium D1034 unless otherwise marked. Silicon diodes are marked S1 and are SR162 unless otherwise indicated. All resistor values are noted in ohms and are A watt unless marked otherwise. All capacity values are in ,uaf. unless marked otherwise.

GENERAL DESCRIPTION By preliminarily stressing several basic aspects of the printer operation, and keeping these aspects in mind, the detailed description which follows will be more clearly understood.

Referring for a moment to FIGURE 2, the general arrangement of the mechanical components of the printer can be seen. The drive motor 26 is preferably mounted on the base structure but for convenience of illustration is shown moved to an upper location. The printer has a dual row typewheel 22 which, during printer operation, is constantly rotating, being secured on a shaft 24 which is suitably journalled in the frame of the machine (not shown) and is driven by a synchronous motor 26 through

pulleys

28 and 29 and a pulley belt 30. Also secured to rotate with shaft 12 is a two (2) notched clock wheel 32 and a sixty-four (64) notched clock wheel 34. The two notches 35 and 36 on clock wheel 32 are indexing points at the beginning-of-count position on the typewheel 22 while the sixty-four (64) notches 37 on clock wheel 35 are aligned with respect to the sixty-four character positions around the typewheel 22.

Clock wheels

32 and 34 are metallic discs made of high permeability magnetic material (such as wrought iron or mild steel), the notches in each, as the edges of the discs pass close to the magnetic pick-up members, causing a change in flux density in the magnetic field around the index coil 38 and impulse counting coil 39 of the pick-up members. This change in flux density induces a surge of current and a changing in the pick-up circuits. The voltage signal is amplified and shaped by respective amplifiers 41 and 43 (FIGURE 1) which feed the indexing and counting signals to the machine control circuits, to be hereinafter described.

Clock wheels

32 and 34 must not become permanently magnetized, otherwise the machine will not work.

The machine is a serial tape printer, it prints one character or symbol or causes a space function of a message one unit at a time in a single line on a tape, the character to be printed being chosen from one or the other of the inner row 42 or the outer row 44 of the dual row typewheel 22. In the preferred embodiment, the characters in one row are different from the characters in the other row. Thirty-two different print characters or symbols can be included in each row and are repeated at 180 intervals in the same row.

Still referring to FIGURE 2, a paper tape feeds from right to left from a supply roll (not shown) by mechanism described in detail in the aforesaid parent and in a co-pending divisional application. To aid in understanding, the inner typewheel row 42 is on the incoming tape side and the outer typewheel row 44 is on the tape feed-out side.

To serially print a message on the tape in this machine without overprinting and in order to operate the machine in a useful manner, the machine is capable of four basic modes of operation, now briefly described, and referred to throughout the following description.

(1) If the character to be printed is located on the inner typewheel row, the machine will print-first and then space the tape. This will be referred to as the PRINT- SPACE" mode of operation. Note, at the end of this operation the tape is properly positioned to undergo a succeeding PRINT-SPACE operation if the next character to be printed is located on the inner row.

Although the tape has been stepped so that the character just printed is now directly under the outer typewheel row, a character selection from that row will not overprint because of the next described mode of operation.

(2) If the character to be printed is located on the outer typewheel row, the machine will space the tape first and then print the character. This will be referred to as the SPACE-PRINT mode of operation. Note, at the end of this mode of operation the tape is positioned with the just printed character under the outer typewheel row, the same .as the finish position of the PRINT-SFACE mode of operation. Thus the machine is ready to undergo a succeeding mode of operation which can be either PRINT-SPACE or SPACE-PRINT depending upon which row contains the character to be printed. In this manner, the resultant printed message will be properly serially recorded on the tape.

Determination of one or the other of the above two ibriefiy described modes is by a sixth bit added to a five unit code signal combination, which in fact makes the code signal a six bit combination. Depending upon the presence or absence of a positive sixth bit pulse in the received signal, the control circuitry, which will be fully described, selects the mode of operation to record the desired character from the proper row.

Another point to be understood is that there are two print hammers, one of which is used only with the inner typewheel row of characters and the other of which is used only with the outer typewheel row of characters.

(*3) A third mode of operation is designated the space but no printing mode, i.e., SPACE-NO PRINT. Thus, if a space code signal is received, there is an automatic inhibiting of the operation of the counting and printing control circuits as a result of which, no printing actuation occurs. Yet at this time, a space signal is immediately directed to the tape feed mechanism, resulting in a spacing of the tape but no printing.

(4) The fourth mode, entitled MANUAL TAPE FEED, is just what its name implies. This operation is provided by a switch which inhibits counter and printer operations and feeds signals directly to the tape feed mechanism.

As previously mentioned, to hurdle the mechanical speed limitations of tape feed mechanisms, duplicate tape feed devices are provided and their operation is alway successively alternate. This is true regardless of which one of the four modes of operation is utilized.

The ink ribbon feed for the typewheel ink ribbon is stepped once for every second printer cycle of operation. The circuitry for this operation is electronic and will be described.

The printer operates from six lines of data, received in parallel, plus a strobe line. As is conventional, each line furnishes one of two signals, sometimes referred to as yes-no, mark-space or pulse-no pulse. Information can be accepted at the rate of from 0 to 30 characters per second.

For convenience, the exemplary printer has been arranged to receive code signals in the form of five-unit binary code combinations. The source of the signals is not a part of the present invention; it may be a telegraphic transmitter, the output from a data computor or a data storage device such as a magnetized tape record. Merely by way of example, it signals are derived from a tape storage device, the binary signals recorded on the magnetic tape induce pulsating voltages in the pick-up head, which voltage signals can be amplified and/ or shaped as desired and applied through corresponding leads to a five stage binary counter circuit (see top of FIGURE 1) of the printer of this invention. The code combination jams or pre-sets the counter to a desired count condition. Also, a sixth bit signal line leads to the sin le stage binary counter No. 6 (also at the top of FIGURE 1) which determines the selection of operation modes 1 and 2 (PRINT-SPACE or SPACE-PRINT), and a seventh input signal line to the strobe input (No. '7 at bottom left of FIGURE 1).

The position detection pulse generated counts correspond to five unit binary code numbers. Many arrangements of the order of characters represented by serially generated binary code combinations are, of course, possible. For example, the 180 out-of-phase positions 1 and 33 on the typewheel and on the sixty-four notch clock disc could both be for the two characters A and B, and the serial pulse count of one from the sixty-four notch wheel as expressed by the five unit binary code would be 00001. The binary code 00001 represents both characters, but the characters are on different rows, e.g., A would be on the inner row of the typewheel and B on the outer row of the typewheel. Similarly, C and D could be represented by a two count pulse, which is the five unit binary code 00011, E and F by the three count pulse or code 00100 and so on for thirty-two sets of two or a total of sixty-four different characters (symbols, numbers, etc.).

Returning to the binary counter, as has been stated, it is the destructive read-out type, i.e., the counter is preset by the received simultaneous code signal and pulses sent into the counter by the sixty-four (64) notch clock wheel 34 will complete the counter operation from the pre-set count, through the thirty-two count whereupon the counter returns to its zero count condition, at the same time providing a control pulse signal to operate the printer functions.

In destructive read-out, the code combinations repre senting characters on the incoming signal lines are the complement of the serially produced binary signal count from the printer clock disc. Thus, using the five unit binary code (thirty-two numbers not including zero), the complementary number for the A and B print positions, noted previously as being 00001 in the printer, wouldibe 31 or 11111.

To print A or B, therefore, the incoming code signal on lines 105 would consist of a pulse on each line or 11111 which will jam or preset the binary counter to 31'. Thus when one (1) pulse is received from the sixty-four notch clock disc (after an index pulse) one or the other of the two characters A and B can be printed. With A located on the inner row 42 of the typewheel 22 and B on the outer row 44, the absence or presence of a signal pulse on the sixth incoming line will be used to determine whether the desired character to be printed is A or B.

CONTROL CIRCUIT AND OPERATION Inasmuch as the mechanical printer components are actuated and, in fact, powered by the control circuit, the control circuit will be first described, leaving the specific details of pertinent mechanical components of the printer and the ink ribbon mechanism to be described in detail in a later portion of this specification.

In describing the control circuitry, reference will be primarily to FIGURE 1 and the symbolized components such as the binary counter registers, and units, delay units, current drivers, etc. The specific manner in which each circuit component accomplishes its function will be understood by those skilled in the art and relative to the ink ribbon control and power circuitry is clearly apparent from the detail circuits in FIGURES 6 and 7.

As has been forenoted, the printer has four modes of operation, PRINT-SPACE, SPACE-PRINT, SPACE-NO PRINT and MANUAL FEED-OUT. The circuits to accomplish these modes will be described in the order named.

PRINT-SPACE MODE The print-space mode records a character on the inner row of the typewheel 22 and then feeds the tape 40 one step. Because the adjacent two difierent characters on the typewheel inner and outer rows 42 and 44- are represented by a single incoming simultaneous five unit binary code to binary counter 50 and are also represented by a single serial binary count (complement of the simultaneous code) from the clock disc 34, one additional incoming data line 6 is used to determine whether there will be a print first-space later operation or a space first-print later operation. If no information is received from data line 6 by the sixth register 46, the character desired for selection will be on the inside row at of typewheel 22, and accordingly, the character must be printed first and the tape 40 must then be stepped. In the print first-space later condition, binary code information is received on lines #1 through #5 to the binary counter registers 5l55 and no signal will be present on line #6 to register 46. At the same instant a strobe signal will be received on line '7 which is connected to a 150 microsecond relay 56 to assure that the received data on lines l-S is completely entered in the registers 51 through 555 of counter 50.

From the 150 microsecond delay 56, the strobe signal pulse passes through a circuit line 57 to several branches, one of which is a ribbon feed divide-by-two register which requires two consecutive pulses to 0pcrate a ribbon feed one-shot multivibrator 60 of 14 1nilli seconds duration which in turn feeds a current driving stage 62 to activate a ribbon feed solenoid 64 to move the inking ribbon 66 (see FIGURES 2, 3 and 4). Thus the ink ribbon feed mechanism will be activated once for every other strobe input signal.

The 150 as. delayed strobe pulse on line 57 is also presented to a space-no print blocking gate 68 which, as will be later described, is blocked only when a simultaneous 00000 condition is present in binary counter 50. So long as a character signal is present on input lines 1-5, the blocking gate 63 passes the delayed strobe pulse to an A register 70, cocking the A register 70 to enable acceptance of indexing signal information from the amplifier 4.1 of the two notched index wheel 22 on the typewheel shaft 24. Cooking of register A pulses a 14 ms. delay one-shot 72 which is tripped to provide a 14 ms. blocking of a reset line 76 to a B register 74, by means of an end-of-count and gate 75.

The first index pulse from the pick-up coil 38 of the two notch Wheel 32 passes through its amplifier stage 41 to the reset line of the A register 70 which trips and, in turn, trips the B register 74. Tripping of B register 74 through a circuit line 78 opens the and gate 79 to the binary counter input line 80, permitting the sixty four (64) notch clock disc 34 to serially enter its pulse through its amplifier stage 43 and the opened an gate 79 into the 2 counter stages of binary counter 50. The serial pulses entered into the 2 counter registers 5155 complete the count, previously pre-set by the received simultaneous binary code data on lines 15, to zero. The final serial pulse from clock wheel 34, which clears the binary counter 50, gives rise to an output of the fifth stage 55 which feeds back through previously described reset line 76 to and through the end of-count and gate 75 to turn off the B register 74 which, in turn, closes the count and gate '79.

If an end-of-count signal on the reset line 76 from binary counter 50 occurs before the 1.4 millisecond delay 72 (which controls the end-of-count gate 75) has completed its time cycle, the end-of-count-gate 75 remains closed and the B register 74 will not be turned off. Accordingly, the sixty-four (64) notch wheel 34 and pickup 39 will continue to dump pulses through the counter input gate 79 into the 2 counter registers 51 through 55 (which at this stage of the cycle are not longer pre-set) for thirty-two more pulses (186 rotation of typewheel shaft taking 15.2 ms.) and the ensuing end-of-count pulse through line '76 to the now open end-of-count gate will reset the B register 74, closing the count gate 79.

When the B register becomes reset, a signal goes out on a circuit line 81 to a 500 microsecond delay one-shot 82 and prevents the #6 register 46 from being prematurely reset. This same signal from B register 74 on line 81 also goes to three additional units, (1) a paper feed and gate 85, (2) a print hammer and gate 83 which controls an actuating signal to the print-space (PS) print hammer actuation circuit, and (3) a second print hammer and gate 8 2- which controls an actuating signal to the space-print (SP) print hammer circuit.

In the presently considered print first-space later (PS) condition, the PS print gate 83 has been initially conditioned by the fact that there was no data input on the input line 6 to register 46 and, therefore, when the pulse from B register feeds to the PS print gate 83, the signal passes to a phasing one-shot delay 86 which in turn pulses a one-shot multi-vibrator 87 and a current driven stage 83, which in turn energizes a PS hammer operating solenoid 89. When PS solenoid 89 is energized, the corresponding print hammer 90 (see FIGURE 2a) is caused to record the selected character from the inner type- Wheel row 42 on the tape 40.

Because in this PS mode of operation no data was received on the receive signal line 6 to register 46, the aforedescribed paper feed and gate 35 was conditioned at the same time as was the PS and gate 83 so that when the pulse comes from B register 74, the signal passes through the feed and gate 35 and a pulse is sent to a paper feed divide-by-two register 94 which in turn pulses one of two paper feed one-

shots

98 or 100 to trigger a corresponding one of two current drivers 101 or M2, which energizes an associated one of two feed operating solenoids 103 or 164. Successive pulses to the paper feed divide-by-two register 94 operate alternate ones of the two

paper feed solenoids

103 and 104.

SPACE-PRINT OPERATION Considering now the second mode of operation, if the character to be printed is located on the outside row 44 of typewheel 22, a space first-print later (SP) operation is required. In this instance, data information will be received on the input line 6 to register 46 coincident with the received binary code data on lines 1-5. A signal data pulse on line 6 resets register 45 and sends current through circuit line 108, a branch of which feeds the current to drive a 5 millisecond delay 110. After the 5 millisecond delay, a pulse from the delay unit through a circuit line 111 by-passes paper feed and" gate 85 and will directly enregize the paper feed divide-by-two register 94 to alternately drive one of the paper feed oneshots 98 or 101 the associated one of the current drivers 101 or 162 and finally the associated one of the two teed solenoids 163 or 1M. The paper tape 40 is thus stepped after only a 5 millisecond delay without waiting for an output pulse on line 81 from the B register '74.

The #6 register 46 also determines which of the two hammers, the inside PS hammer 90 or outside SP hammer 112, is to be used for printing. In this instance, SP mode of operation, the output from the 0 side of register 46, which is now in reset condition, will condition the SP print hammer gate 84 so that when an output pulse from B register 74 is received on line 81, the SP print hammer gate 84 is open and will feed a pulse to the SP phasing one-shot delay 114, thence on to the SP one- 8 shot multivibrator 116 and finally t0 the current driving stage 118, energizing SP print hammer solenoid 119 to actuate the SP print hammer 112.

The output pulse from B register 74, as has been described in the PS mode, also pulses the 500 microsecond delay one-shot 82 which clears the #6 register 46 to its set condition and relieves the SP controls through line 1 33 on the paper feed gate and the SP print hammer circuits.

SPACE-NO PRINT O'PERATION Considering now the third mode of operation, the signal operated tape feed-out function (space-no print), no data is entered into the 2 binary counter 50 nor through the #6 line to register 46 (i.e., the binary code s gnal 00000 and a sixth 0). However, the strobe pulses to strobe line 7 will be continuously sequentially received. 0 condition circuits between binary counter 50 and the space-no print and gate 67 provide for the 0 condition of all of registers 51-55 to open the space-no print control gate 67, which in turn conditions the previously described space-no print blocking gate 68 to closed condition. When gate 68 is closed, it prevents the delayed strobe pulses on strobe input delay line 57 from passing through to the A register 70 and this in turn inhibits the count triggering function of the index pulses from the two notch wheel Nevertheless, the delayed strobe pulse in line 57 is channeled to both the ribbon feed mechanism divide-by-two register 58 and through an and gate 120, which is conditioned by the 60000 controlled pulse in circuit line 57 from the space-no print control gate 67, to the aforedescribed 5 millisecond delay 11%. From delay 11% the pulse is fed through line 111 to the divide-by-two paper feed register 94 and alternately through delays 98 or and current drivers 191 or 102 to the associated fccd solenoid 193 or 164.

Thus, one or the other of

tape feed solenoids

103 and 104 is energized to step the paper tape 48 one step for each strobe pulse received on line 7 and this stepping occurs without actuation of the print selecting mechanism which is completely inhibited so no printing of characters and no counting of pulses occurs.

MANUAL TAPE FEED-OUT OPERATION In the fourth mode of operation, manual tape feed-out, a manual switch button 122 (bottom center of FIGURE 1) is closed to ground. While the printer motor is running, closing of switch 122 will condition a manual ribbon and feed control and gate 124, permitting the ampiified indexing pulses from the two notch wheel 32 to pass through the gate 124 to the aforedescribed ribbon feed divide-by-two register 58, and thence on to the ribbon feed circuit. The pulses in this circuit branch off through a manual feed and gate 126 to the divide-by-two paper iced register 94 and thence through the aforedescribed paper feed circuit to step drive the paper feed mechanism.

The ribbon feed mechanism is operated at this time (as well as in all other modes of operation) even though no printing takes place and such feed is permitted due to the fact that it simplifies the electronic circuitry.

The SP mode of operation up through the pulsing of the 500 s. delay 82 will be completed in from 15 to 29.85 ms. The strobe pulses and received signal groups are received every 33 ms. or 30 times each second which will permit at least a 3 ms. period between each character counting cycle.

MECHANICAL STRUCTURE AND OPERATION Referring primarily to FIGURE 2, the relationship between all mechanical components can be seen. The motor 26, pulleys 2%, 29, belt 38, typewheel and clock disc shaft 24 typewheel 22, the two (2) notch indexing clock disc 32, and the sixty-four (64) notch position pulse clock disc 34 have been described.

Tape feed.The dual tape feed mechanism, the two independent driving assemblies which operate alternately in response to successive operating cycles of the machine is fully described in the aforenoted parent application and is disclosed and described in a co-pending divisional application Serial No. 362,046.

Printing mecha'nism.The print hammer mechanism 1% is shown in combination with the other mechanical components in FIGURE 2 and is herein described primarily because of its relationship to the ink ribbon. The FS and SP print hammer solenoids 8? and 11), previously described in conjunction with the control circuit, are energized, in response to receipt of a character code and a signal determining which of the two solenoids is to be enregized, in timed relation to the retation of characters on the rim of the typewheel so a print hammer will impact the proper character in its pass above the printing station.

As previously described, two distinct print hammers 90 and 112 are provided, hammer 90 being associated with the PS solenoid 89 and used to print characters carried by the typewheel inner row 42, and hammer 112 being associated with the SP solenoid 119 and used to print characters carried by the typewheel outer row 44. The two hammers 9i! and 112 are clearly seen in FIGURE 2 arranged in tandem along the tape feed path and adjacent the bottom center of the typewheel 22. Each hammer has a low mass and consists of a fiat bar-shaped shank and a small impact head, the shanks being reciprocally guided in a slotted bracket device (not shown) secured to the machine base. Movement of each hammer is in a straight vertical path radially with respect to the typewheel. One edge of each hammer shank is notched to receive an end of an associated

solenoid armature lever

200, 2%. A hammer return spring 202 and 264 is fastened to the lower end of each hammer shank, the other ends of the springs being fastened to a spring anchor bracket 2% which is fixed to the machine support structure. The hammer heads, in retracted position, will be disposed in recessed cavities in the upper surface of a tape guide plate. Armature levers 280 and 2&1 extend side by side toward the two print hammer electromagnets t3) and 119 and are pivoted on a horizontal rod mounted in cars of the bridges and of the electromagnets.

In the printing operation, if the PS magnet coil 89 (for example) is energized by the control circuit, the pole end of armature 260 is pulled toward the electromagnet, pivoting on its support rod. The opposite end of armature 2% moves up sharply to vertically shift the PS hammer 99 causing its head 194 to strike the underside of tape 44 forcing it against the ink ribbon 130 and the ink ribbon against the appropriate print character on the inside typewheel row 42 to cause an inked imprint on the tape. Energization of electromagnet 39 is a one-shot of minute duration, the coil being de-energized before the hammer impact occurs. Accordingly, the hammer and armature retract springs, upon impact rebound, cause immediate return of the hammer 90 to its rest position.

Mechanical actuation of the SP hammer 112 is identical to that of hammer 9h excepting its head impacts the tape and ink ribbon against the selected character on the outer typewheel row.

Ink ribbon meclzanism.-This mechanism includes ink ribbon feed and automatic direction reversal when a reel is fully unwound and will be described with specific reference to FIGURES 3, 4 and 5 and general reference to FIGURE 2.

In this mechanism as in the tape feed and the printing mechanism, operation control and power resides in the aforedescribed electronic printer circuit, a ribbon movement or shift being accomplished each time an impulse signal causes momentary energization of the ribbon feed solenoid 64.

The mechanical components of the ink ribbon mechanism are mounted on a vertical plate-like bracket 232 10 (FIGURE 4) which is secured to the machine base plate. The bracket has been omitted from FIGURE 2 for purposes of clarity.

A small bent shelf 234 extends forwardly from the approximate mid-point of the lower edge of bracket 232 and mounts the ribbon feed solenoid 6%. This solenoid 64 faces the vertical plate bracket 232 and its plunger 236 shifts fore and aft in a horizontal path, being biased in an aft direction toward the bracket 23.2 by an encircling coil spring 233. A link 24% in approximate alignment with plunger 236 is pivotally fastened at one end to the rear end of plunger 236 and has its other end pivotally connected by a common pivot to one end of a guide link 2 52 and one end of an operating link 244. Guide link 24?; has its other end pivotally fastened to a fixed lug 246 While the other end of the operating link 244 is pivotally fastened to the approximate mid-point of a pawl lever 248. The rearward end of pawl lever 248 is pivoted to a fixed lug 259 and its forward end pivotally carries a pawl 252 which is biased by a pawl spring 254 into engagement with a ratchet wheel 256 non-rotatably fastened on a ribbon reel drive shaft 258.

As is clearly apparent from FIGURE 3, the reel drive shaft 258 carries other components, to be described hereinafter, and each of its ends journalled in one of a pair of spaced ears of a U-shaped bracket 266 rigidly secured on the support bracket plate 232. The mounting of shaft 258 in bracket 269 permits a slight axial shift for ribbon feed reversal purposes, as will be described. Returning to FIGURE 4, the disposition of

links

246, 242, 244 and lever 248 is such that a forward shift of the solenoid plunger 236, when solenoid 64 is energized, will tend to vertically align the guide link 1242 and operating link 244, which forces the pawl lever 248 to shift clockwise. This movement of lever 2% will shift pawl 252 to engage a tooth of and rotate the ratchet wheel 256 and shaft 258 one step clockwise. A spring loaded detent 262 (behind the ratchet wheel) engages the ratchet to prevent reverse movement of the shaft 258 when the pawl retracts back over the ratchet teeth.

Retracting force is derived from stored energy in coil spring 238, the retract limit stop position being determined by abut-ment of the combined pivot connection of links 24%, 242 and 244 with the end of an adjustment screw 264 threaded in the bracket plate 232.

Two parallel and horizontally arranged ink ribbon spindles 270 and 272 are journalled on the front side of the support bracket plate 232 and extend adjacent the ends of the ribbon operating shaft 258.

Large gears

278 and 280 are attached to respective ribbon spindles 27d and 272 and

ink ribbon reels

282 and 284 slip over the spindle ends 286 and 288 and drive connect to the spindles by means of the fingers 2%. The reels are locked in place by the swivel lock tabs 292. As shown in FIGURE 2, the ink ribbon 23% passes from the inner side of one reel up and over the tape guide plate, over the hammers 9i and 112 and over the tape 4t). A suitable ribbon guide device (not shown) is preferably fastened on the tape guide plate 210 to maintain the ink ribbon 236 in its lateral path directly under the typewheel 22.

Referring now to FIGURE 3, it will be seen that two

small gear units

274 and 276 with

axial sleeves

294 and 296, having

radial flanges

298 and 30 3 spaced from the

gear portions

274 and 276, are non-ro-tatably fixed on the ribbon driving shaft 258. Note the sleeves are also non-rotatably and axially secured on shaft 258 and will be described further in connection with ribbon feed reversal. In FIGURE 3, the right-hand small gear 274 is meshed with the righ-hand ribbon spindle gear 278 while the left-hand small gear 276 is not in mesh with its spindle gear 2%. A slight leftward axial shift of the drive shaft 258 will disengage the right-hand gears 2.74 and 278 and engage the lefthand gears 276 and 28%, this function being a part of ribbon reverse. But for the present, it is noted that with

gears

274 and 278 in mesh, stepped rotation of 1 1 ratchet wheel 256 clockwise (FIGURE 4) will rotate the right ribbon reel 282 counterclockwise to wind ribbon 23th on reel 282 and remove ribbon from the lefthand reel 284. When gears 276 and 280 are meshed, obviously, the winding operation between reels is reversed with reel 284 being the take-up reel.

With respect now to the automatic reversal mechanism, each of the small

gear unit sleeves

294 and 2% non-rotatably carries a gear worm and 384 respectively between the associated

small gear

274 or 276 and associated radial flange 2% or 3%. Worms 302 and 334 can be splined to the sleeves and assembled before the sleeve and gear are assembled as a unit. Each worm 392, 364 is biased against its assoicated radial flange 2% or 309 by a coil spring 306, 3% to afford a cushion or delay if the

gears

274 and 278 and 28% do not initially mesh when drive shaft 258 is shifted.

Best shown in FIGURE 4, each reel includes an associated linkage which constitutes a reel condition sensor and drive shaft reversing actuator. One is right-hand and the other is left-hand, otherwise they are identical, so only the right-hand sensor-actuator 312 will be described. Portions of the sensor-actuators are deleted from FIG- URE 3 for clarity but details can be seen in FIGURES 4 and 5. The actuator 312 is U-shaped and is pivotally mounted on cars 314- and 315 mounted on the support bracket plate 232 behind the assoicated ribbon spindle gear 278. One end 3113 of the U-shaped member is formed as a long arm which projects to a position inside the annular hub 317 in the rear of ribbon reel 282 (see FIGURE 5) terminating in a right-angled curved finger 318. A spring 32f) connected between an ear 322 on arm 316 and an anchor lug 324 on bracket 232 biases the actuator 312 clockwise (FIGURE 4) causing the curved fin 'er 313 to engage the inside surface and edges of the reel hub 317. If ink ribbon is present on the reel 282, the finger 318 will reach a limit position determined by the ribbon. However, if the ribbon is exhausted the finger 318 moves out through a reel hub opening 326 under urging of the spring 320.

\Vhen the actuator 3E2 senses an exhausted reel and shifts to its full clockwise position with finger 318 through a reel hub opening 326, a pin 328 carried by a short arm 330 on the opposite end of the U-shaped actuator shifts up into engagement with the threads of worm 302. Since the ribbon feed drive shaft 2553 continues to rotate in steps as the control circuits demand ribbon feed, the worm wheel 302 rotates clockwise and the direction of feed of its threads against the axially immovable pin 31% will shift the shaft to the right and cause meshing of

gears

274 and 278, after which shift, reel 282 becomes the takeup reel. The first turning movement of reel 232 as a take-up reel will cause retraction of the pin 238 of actuator 312 because the edges of the reel hub openings 326 and the winding ribbon will force the actuator 31?. to shift counterclockwise against the urging of its bias spring 320.

In the operation of the ink ribbon mechanism, a ribbon feed indexing step will occur once for each two times the control circuit feeds a signal to the ribbon feed divide-bytwo register 58 (FIGURES 1 and 7). As has been described, once during a cycle of any of the four operative modes, a signal pulse is fed to the ribbon feed divide-bytwo register 58 which controls a ribbon feed one-shot (14 ms.) 6%) (see FIGURES l and 6) to momentarily energize the ribbon feed solenoid 64. In FIGURE 4, whenever ribbon feed solenoid 64 is momentarily energized, the plunger 236 reciprocates forward against the bias of spring 238 and returns back under spring force. Forward movement of plunger 236 indexes the ribbon drive shaft one step by means of

linkage

242, 244, 248, pawl 252 and ratchet wheel 256. A dctent 262 bears on the ratchet wheel teeth to assure single step indexing by the pawl 252. The ratchet 256 being fixed to shaft 258 causes shaft 258 to rotate clockwise one step to rotate two

small gears

274 and 276 attached to ends of the shaft. One

or the other of

gears

274 and 276 is meshed with an associated

large gears

278 or 280 and rotates that gear. As illustrated in FIGURE 4, gears 274 and 278 are meshed, so gear 278, its spindle 270 and the ink ribbon reel 232 carried by the spindle are rotated to Wind-up the ink ribbon in indexed steps, the ink ribbon being removed from the other reel 284. Thus, each time the solenoid 64 is energized the ink ribbon 230 is advanced a slight distance until one of the two ink ribbon reels 282 and 284- is almost emptied.

The sensing levers 316 and SM are employed to activate the ribbon reversing mechanism as seen in FIC- URES 35. In order to load (place a reel on) the ink ribbon spindles 2'70 and 272, sensing levers 316 and 316' must be moved downward, as viewed in FIGURE 4, by depressing

manual operating rods

340 and 342. This enables

ink ribbon reels

282 and 284 to be slipped onto spindle ends 236 and 288 with the curved fingers 318 and 313' of

sensing levers

316 and 316 fitting inside the hollow hub 317 of each ink ribbon reel (FIGURE 5). As the ink ribbon 2% completely unwinds from one ink ribbon reel, the

curved finger end

318 or 318 of lever 316 or 316' (until now, blocked by the ink ribbon wound on the reel) is now unblocked and moves upward into an opening 326 on the inside rim of the ink ribbon reel hub 317 (see FIGURE 5). This enables a shift of

sensing lever

316 or 316 under bias of spring 320 until the

328 or 328 on short arm 330 moves into engagement with the threads of worm gear 382 or 304. If gear 3232 has its threads engaged by sensing lever shift pin 328, clockwise rotation of the gear by shaft 258 will cause the shaft assembly to shift toward the right until gears 2'74 and 273 are in mesh (FIGURE 3) causing shaft 258 to drive spindle 270 and its ribbon reel 282. Positive drive rotation of the ribbon reel will wind the ink ribbon on that reel and, through the sensing lever 316, will remove the reversing pin 328 from the threads of gear 302.

Gears

274 and 278 will continue to rotate the reel 282 until reel 284 is empty, at which time its sensing lever 316 will be raised to place its pin 328 into the worm threads of gear 394 to shift the drive shaft assembly to the left, meshing

gears

276 and 280, and place positive drive on reel 284 instead of reel 282.

To make certain that shaft 258 remains in one or the other position until a shift movement is desired, a spring loaded detent pin 344 engages alternate ones of two side by

side grooves

346 and 348 in the sleeve 296 of the lefhand small gear unit on the ribbon drive shaft 258. When the shaft assembly is shifted one way or the other to reverse the ribbon feed, one of the

grooves

346 or 348 moves laterally away from the detent pin 344 which is then depressed by ridge 350 between the grooves, and the detent pin is then biased into the other groove to hold the drive shaft assembly in such position until the ink ribbon is again reversed.

The invention may be embodied in other specific forms Without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a high speed serial printer which undergoes a cycle of operation responsive to reception of each of a plurality of different data communication signals, an ink ribbon feeding and reversing assembly comprising: two reels; an ink ribbon passing between said two reels and adjacent the print positions of said printer; a reel feed mechanism adapted to alternatively be connected to one or the other of said two reels; means responsive to ribbon condition on said reels to selectively connect said feed mechanism to an appropriate one of said two reels; an electronic power circuit connected to actuate said reel feed mechanism and step feed said ink ribbon assembly; an electronic control circuit responsive to each cycle of printer operation to provide a ribbon control pulse; and a divide-by-two register receiving said ribbon control pulses and responsive to alternate control pulses to provide an actuation signal to said power circuit to trigger operation of said electronic power circuit.

2. In a high speed serial printer which undergoes a cycle of operation responsive to reception of each of a plurality of dififerent data communication signals, an ink ribbon feeding and reversing assembly comprising: two reels; an ink ribbon passing between said two reels and adjacent the print positions of said printer; reversible drive means, with automatic shifting means, to alternately drive either one of said reels responsive automatically to substantially complete unwinding of the ribbon from the other one of said reels; an electronic ribbon power circuit including a spring loaded solenoid connected to step feed said reversible drive means; an electronic control circuit responsive to each cycle of printer operation to provide a ribbon power circuit control pulse; and a divideby-two register receiving said ribbon control pulses and responsive to alternate control pulses to provide an actuation signal to said ribbon power circuit to trigger operation of said solenoid to step feed said drive means.

References Cited by the Examiner UNITED STATES PATENTS 2,672,092 3/1954 Beattie l0l-336 2,714,850 8/1955 Kistner 101-336 2,723,346 11/1955 Magnuson 317-123 3,122,678 2/1964 Mariot 317-5 WILLIAM B. PENN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,232 229 February 1 1966 Hilding A. Anderson It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4 line 58 for "alway" read always column 6 line 50 for "relay" read delay column 7 line 60 for "enregize" read energize column 9 line 15 for "enregi zed" read energized column 11 lines 14 and 27 for "assoicated" each occurrence read associated line 53 for "238" read 328 Signed and sealed this 10th day of January 1967.

( Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNF Commis ioner of Patent