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PRINTING APPARATUS AND CONTROLLING
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of application, Ser. No. 806,430, filed Mar. 12, 1969, now abandoned.
This invention relates to a printing apparatus which can be used in connection with a telephone receiving set and is controlled by alternating current signals sent over the telephone line. The printing apparatuses small and compact and can be housed in a small container secured to the telephone subscriber set.
Automatic type printing controlled by received electrical signals is old in the art. Generally, the printing devices were modified typewriters and were not very fast. The present invention uses a single type wheel which turns all the time at a constant speed. A small hammer operated by a magnet prints a selected 20 character on the record sheet. The typing action is quite fast because the rotating wheel and the hammer action are the only mechanically moving objects during the typing of a single line.
A feature of the present invention is a tone decoding 25 circuit and a storage circuit used to apply a control voltage to the printing circuit.
Another feature of the invention is a timing means coupled to the rotating type wheel which determines when an operating pulse is applied to the printing mag- 30 net.
Another feature of the invention is a plurality of AND circuits which send the operating pulse to the printing apparatus only when the type wheel is in the proper position and when a printing signal has been 35 received.
For a better understanding of the present invention, together with other details and features thereof, reference is made to the following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is an isometric view of the telephone receiver set combined with the tone decoder and printer. 45
FIG. 2 is a plan view of a ticket showing the results of the printing action.
FIG. 3 is a side view, with some parts broken away, of the receiver shown in FIG. 1.
FIGS. 4, 5, and 6 when placed side by side, are a 50 schematic diagram of connections showing the entire circuit of the printing control unit.
FIG. 7 is a schematic diagram of connections of one of the storage multivibrators used in FIG. 4.
FIG. 8 is a cross sectional view of the rotating disk 55 used in FIG. 5.
FIG. 9 is a schematic diagram of connections of the photosensitive transducers used in the rotating disk assembly shown in FIGS. 5 and 8.
FIG. 10 is a schematic diagram of connections of the 60 space circuit shown in block form in FIG. 6.
FIG. 11 is a schematic diagram of connections of the notch filter circuit shown in block form in FIG. 4.
FIG. 12 is a schematic diagram of connections of the 6S AND gate shown in FIG. 4.
FIG. 13 is a schematic diagram of Connections of the print control circuit shown in block form in FIG. 6.
DESCRIPTION OF THE PREFERRED
Referring now to FIG. 1, a telephone subscriber set 10 is shown having the usual digit buttons 11, control buttons 12 and 13, and a hand set 14. The subscriber set may include storage compartments 15, a start bar 16 and a slot 17 for receiving automatic signalling cards. A base compartment 21 includes a recess 22 for receiving the receiver portion of the hand set and a similar recess 23 for receiving the microphone portion during a recording and printing operation.
The printing assembly 24 is positioned in the base compartment 21 in a well 25, open at the top so that an operator can insert a blank card 26 before the printing operation and then remove the card after the information has been printed thereon. In FIG. 1, a printing wheel 27, on a square or splined shaft 28, is shown in the well. Also, a knurled wheel 31 is indicated for moving a roll of paper behind the card 26 if a carbon copy of the printed matter is desired. To the left of the printing well there are seven control keys 30 which are used to start and stop the operation, to release the card, and to operate other components in the system not connected directly with the printing apparatus.
FIG. 2 shows a typical card 26 used with the telephone banking system. It may contain pre-printed items such as addresses, blank spaces for a buyers number 32 and signature 35, and a place 33 for the printing apparatus to print the price of an article or service.
The side view of the telephone set, FIG. 3, shows the printing wheel 27 on its shaft 28, coupled by an arm 29 to move the print wheel along the shaft during the printing operation. The arm 29 is secured to a base plate 36 which supports an electromagnet 37, and a print hammer 38, behind the card 26. The electrical connections to the magnet and control buttons will be described later when the entire circuit is disclosed.
FIGS. 4, 5, and 6, when placed side-by-side show a schematic diagram of connections of the entire electric circuit, but showing many of the circuit elements in block form. This circuit receives coded tonal pulses from the receiver portion of the telephone headset, decodes the pulses, and then controls the printing mechanism to print a line of digits on the card 26 in the space 25.
A pick-up coil 30 may be wound on an iron core 40 for greater efficiency. Coil 30 is connected to the input terminals of an amplifier 41 and the output terminals of the amplifier are connected to a band pass filter 42 and then to a low pass filter 43 and a high pass filter 44, The output of the low pass filter 43 is applied to another amplifier 45 and then sent to a first group of notch filters 46-1, 46-2, 46-3, and 46-4, each of which is arranged to pass only a narrow band of frequencies. The details of the notch filters are shown in FIG. 11. In a similar manner, the output of the high pass filter 44 is applied to amplifier 47 and then sent to four notch filters 48-1, 48-2, 48-3, and 48-4, each of which passes only a narrow band of frequencies. The eight notch filters are adjusted to pass frequency bands which differ from each other by a substantial amount, these eight frequency signals comprising the coded indicia which control the printing apparatus. Each received signal, at pick-up coil 30, includes two signal waves, one
matching one of the filters 46 and the other matching one of the filters 48.
The output pulses from filters 46-48 are applied to sixteen AND gates 50-1 through 50-16, each of these gates having two input connections and operating to 5 deliver an output voltage only when input current pulses are received on both input lines. In addition, all the AND gates 50 are connected to an "enable" conductor 155 and permit operation of the ANd gates only when this conductor is supplied with a positive voltage. The 10 details of this AND circuit are shown in FIG. 12. It is apparent from the circuit of FIG. 4 that each filter circuit is connected to four gates 50-1 through 50-4. Each of the gates will be opened only when a combination of two frequencies are received by the pick-up coil 30. These two frequency waves are separated by the filter circuits and then one and only one of the 16 AND gates 50 is opened.
Adjacent to each gate 50 is a bistable multivibrator 2o forming a series 52-1 through 52-16. Each of these multivibrators, sometimes called flip-flops, has a "set" terminal 53 (see FIG. 7), an output terminal 54, and a reset terminal 55. Each of the set terminals 53 are connected to a gate 50 so that, when the gate is opened, an 25 operating pulse is transferred to the associated flip-flop and its conductance is transferred to the left side, increasing the potential of the output terminal 54 and applying a positive voltage to the output conductor. Each of the sixteen output terminals is connected to a con- 30 ductor, 56 through 71, which supplies its positive voltage pulse to a timing circuit which includes at least 15 AND circuits 72-1 through 72-15. All the AND circuits 72 have a common output conductor 73 which is coupled to a print control circuit (FIGS. 6 and 13) and 35 to the hammer magnet 37. The print control circuit also controls the space circuit and the mechanism which moves the print wheel 27 along its shaft 28.
Multivibrator 52-1 has its output conductor 56 con- ^ nected to the space circuit, FIG. 13, and other control circuits to cause the print mechanism to move one space without printing a character. Multivibrators 52-2 through 52-11 are for printing digit characters from 1 through 9 and 0. The output terminals of these circuits 45 are connected to conductors 57 through 66, each of which is connected to its AND circuit 72. Multivibrators 52-12, 52-13, 52-14, and 52-15 control the printing of a dash (-), a period (.), and asterisk (*), and a dollar sign ($) respectively. The output terminals of 50 these circuits are connected to conductors 67, 68, 69, and 70, all of which run to an AND circuit shown in FIG. 5.
Timing Circuit 55
Synchronism between the decoding circuit and the printing wheel is provided by the series of AND circuits 72 and a timing wheel 74. FIG. 5 shows the timing wheel which includes an inner wheel 75 having a flange 76 with a single hole 77 cut in the flange material. A 60 central lamp 78 provides light which shines through the hole 77 as it is turned by the motor 79 and shaft 28. An outer flange 80 surrounds flange 76 and is provided with at least 15 holes 81 equally spaced around the fi5 flange to let light from lamp 78 shine through in a sequential manner. Covering each hole 81 is a photosensitive circuit 82, shown in detail in FIG. 9.
Each of the photosensitive circuits 82 includes a light-to-electric transducer 83 which in this case is a semiconductor unit although other photosensitive units can be used. Transducer 83 is connected to a battery 84 which sends current through the collector and emitter electrodes only when light is incident on the semi-conductor surface. Transducer 83 is directly coupled to a transistor 85 which is biased by a voltage divider to be normally non-conductive. When light activates transducer 83, it conducts and alters the bias on transistor 85 to make it conductive. The emitter of each transistor 85 is connected to a timing conductor 86 which is connected to one of the input terminals of an AND circuit 72 and, as the disk 76 turns one revolution, all the AND circuits 72-1 through 72-15 are sequentially energized by the application of a positive pulse. If none of the conductors from the storage multivibrators are provided with a positive potential there will be no output pulse on conductor 73, but if any of the storage conductors has a positive potential, an output pulse will be sent over conductor 73 to the magnet 37 (FIG. 6) to cause the hammer 38 to print a symbol.
All the AND circuits have the same circuitry, as shown in the detail 72-1. The storage conductor 56 is connected to a voltage terminal 87 in series with a resistor 88. Conductor 56 is also connected to the junction of two diodes 90 and 91. The timing conductor connected to ground in series with a resistor 92.
The operation of the AND circuit is as follows: When there is no voltage on conductor 56 the junction point between the two diodes is close to ground potential because the current is drained through diode 90 and there is no output current. However, if a voltage is applied to timing conductor 86, diode 90 is back biased and no current can flow through it. This raises the potential of the junction point and current is sent through the output buffer diode 91 to the output conductor 73. The hole 77 in rotor 76 is synchronized with the print wheel so that a positive pulse on any one of the storage conductors results in the printing of a character identified with that conductor.
The timed output pulse from the AND circuit is transmitted over conductor 73 to a print timing and shaping circuit 93 (FIG. 6) in series with a capacitor 94. Circuit 93 is a mono-stable multivibrator and includes two transistors 95 and 96 with the usual cross connected circuitry. Circuit 93 times the printing action shapes the printing pulse and allows for the inductance of the print magnet 37 and the inertia of the printing hammer 38. The timing action is made adjustable by varying one of the resistors 97. A printing control pulse is sent from the collector electrode of transistor 96 through diode 98 to a print control circuit 100. At the same time, a portion of the same pulse is sent through diode 101 to a space control circuit 102 to operate a magnet 103, actuate an armature 104, and turn an escapement pawl 105 to move the printing assembly one space so that the next character may be printed in spaced relationship to the first character.
The starting mechanism includes a start key 110 for manual depression. Two pairs of contacts 111 and 112 are closed when the start button is depressed, one pair 111 connected in series with a power plug 113, a systems switch 114, and a magnet 115. When the magnet 115 receives current it actuates armature 116 and
pawl 117 to release a one-revolution clutch 118. The conductor 135 to the print circuit 100 and the other clutch 118 pulls a cord 120 attached to the printing as- sent over conductor 145 to the space circuit, sembly base and pulls the base 36, the printing wheel A short time interval after the space circuit 102
27, and the magnet 37 to the left, ready to start a line of (FIG. 10) is activated and sends a signal over conducprinting. When contacts 111 are closed, a circuit is 5 tor 148 to move the printing assembly 36, a pulse is completed which may be traced from the plug 113, transmitted over a delay circuit including a capacitor through switch 114, over conductor 121, through 150 and a resistor 151. This pulse builds up slowly and, capacitor 122 and contacts 111, then over conductor after a few milliseconds, changes the voltage on the 123, through the winding of magnet 115, and back to base electrode of transistor 152 to make it conductive the other side of the plug by way of conductor 124. 10 and send a reset pulse over conductor 153 to all the When contacts 111 are broken the circuit is broken storage multivibrators 52 and reset or normalize the and the clutch 118 is normalized. one which has been actuated. This action completes
When contacts 112 are closed, another circuit is the space operation, completed which may be traced from the plug 113 over The detailed circuits shown in FIGS. 7, 9, 10,11,12,
conductor 121, contacts 112, relay winding 125, and 13 indicate the actual wiring of these units as emcapacitor 126, and back to the plug 113 by way of con- ployed in a workable system. There are many variations ductor 127. This current operates the relay and closes 0f these units which may be used and the invention is contacts 130 and 131. Contacts 130 are holding con- not dependent upon the details of construction as tacts, connected across contacts 112, and hold the 20 shown. FIG. 7 shows the details of each of the storage relay in its operated condition after the switch 110 is multivibrators 52 to put a positive voltage on a storage opened. Contacts 131 are connected directly in series conductor 56 through 71 when a printing operation is between the plug 113 and a motor 79 which is coupled called for. This circuit includes two transistors 154,155 to shaft 28, print wheel 27, and the timing disk 76. The wjth the usual cross connections. In the normal condiprinting apparatus is now ready to accept signals from 25 tion, transistor 155 conducts and a zero voltage is apthe decoding circuits and print characters on the card plied to its storage conductor. The circuit is activated 26. by applying a negative voltage to terminal 53 to
transfer conductance to transistor 154 and raise the voltage on terminal 54 to a positive value. After the The print control circuit 100 is shown in block in 30 printing operation, a negative reset pulse is applied to FIG. 6 and in detail in FIG. 13. The timed printing terminal 55 by way of conductor 153, and the circuit is signal is received over conductor 135 and is applied to normalized.
two transistors 136 and 137, coupled together to form a FIG. 11 shows the details of a commercial integrated
high impedance Darlington circuit. The output of this amplifier 156 used in connection with a double T notch combination is applied to an amplifier transistor 138 35 filter 157 and coupled to a diode limiter section 158 which is connected to conductor 140 and the print and an output amplifier stage which includes transistor magnet winding 37 (FIG. 6). The return conductor 141 159.
is connected in series with a 50 volt power supply 142, The AND gate 50 shown in detail in FIG. 12 is only shunted by a diode 143 for bypassing inductive 4Q one of many similar circuits which can be used to select transients generated by winding 37. the proper combination of signal frequencies and
The print hammer 38 (FIG. 6) is operated once each transfer two input signals into a single output signal printing cycle except when a space is called for. During which triggers a multivibrator 52. The construction of this time the printing input circuit is short circuited to this AND circuit is based on the requirement of an enaground by a transistor 144 (FIG. 13) having its emitter 45 ble voltage applied over conductor 155 from contacts connected to ground, its base connected through part 160 and a source of positive voltage. Contacts 160 are of a voltage divider to conductor 56A and the top closed when relay 125 is activated at the start of the storage multivibrator 52-1 which is activated each time printing cycle. When the AND circuit is operated, cona space operation is desired. The pulse sent over con- ductance is transferred in its associated multivibrator, ductor 56 is applied to the base of transistor 144 mak- 50 AND circuit 50-16 is made operative when signals ing it conductive and short circuiting the input ter- from F-4 and F-8 are received. This actuates storage minals of the printing circuit. multivibrator 52-16 and a positive voltage is applied to
Control C'rcuit conductor 71 which is connected to circuit 161 (FIG.
"6). This circuit operates signals and lamps which tell a
The space control circuit 102 is shown in detail in 55 second operator at a distant position that the message is FIG. 10. The input to this circuit includes two ended. This portion of the circuit has no bearing on the transistors 145 and 146 coupled together to form a high printing apparatus and will not be described in detail, impedance Darlington circuit. The space signal is Having thus fully described the invention, what is received over conductor 147 (when a character is claimed as new and desired to be secured by Letters printed) and is applied to the base of transistor 145. 60 Patent of the United States, is:
The result is an output pulse amplified by transistor 149 1. In a printing apparatus including a continuously
and sent over conductor 148 to the space magnet 103 running motor, a rotating type wheel driven by the mowhich actuates armature 104 and escapement pawl 105 tor, and a print hammer operated by an electric printto move the printing assembly one space. A space 6J ing signal to impact the rotating type wheel; the imoperation must be made each time a character is provement comprising: a rotating disk driven by said printed and for this reason the output pulse of motor with holes defining the position of each type transistor 96 is divided into two portions, one sent over character on the type wheel; optical sensing means for