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Publication numberUS3870138 A
Publication typeGrant
Publication dateMar 11, 1975
Filing dateJul 13, 1973
Priority dateJul 17, 1972
Publication numberUS 3870138 A, US 3870138A, US-A-3870138, US3870138 A, US3870138A
InventorsMasaaki Ogura, Yostbumi Sato
Original AssigneeRicoh Kk
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Motor control unit for table-type electronic calculator with printer
US 3870138 A
Abstract
The motor operating a printer is on only for as long as necessary to print each keyed-in character, and shuts off for idle periods. The depression of a keyboard key produces a signal which discharges a capacitor, whereby a motor drive transistor is rendered conductive to start the motor. A control circuit is provided which responds to a signal produced for each revolution of the motor and to a clock pulse signal produced in response to a depressing operation of the keyboard to permit the passage of a character pulse synchronized with the rotation of a printer drum to thereby initiate a printing operation. After the printing operation, in the absence of a depressing operation of the keyboard, the charging of the capacitor causes the drive motor to stop, thus enabling an automatic start and stop of the motor in accordance with a depressing operation of the keyboard.
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Description  (OCR text may contain errors)

United States Patent [191 Sato et al.

[ Mar. 11,1975

1 MOTOR CONTROL UNIT FOR TABLE-TYPE ELECTRONIC CALCULATOR WITH PRINTER [75] Inventors: Yostbumi Sato; Masaaki Ogura,

both of Tokyo, Japan [30] Foreign Application Priority Data July 17, 1972 Japan 47-84230 [52] US. Cl ..197/17, 235/61,197/12 [51] Int. Cl. B4lj 23/08 [58] Field of Search 197/11-17, 197/1; 200/33; 235/61; 101/93 C [56] References Cited UNITED STATES PATENTS 2,665,792 1/1954 Stauss 197/17 2,802,163 8/1957 Lambert et al. 197/17 X 2,919,781 l/l960 Rix et al. l97/17 3,354,372 11/1967 Beasley 197/17 X 3,700,087 lO/l972 Ahrns et a1. 197/17 3,753,004 8/1973 Dominic 307/121 OTHER PUBLICATIONS Schaefer, lBM Technical Disclosure Bulletin, Vol. 7,

No. 4, Sept., 1964,-pp. 315-316.

Primary Examiner15dgar S. Burr Assistant Examiner-Edward M. Coven Attorney, Agent, or FirmCooper, Dunham, Clark, Griffin & Moran v 57 ABSTRACT The motor operating a printer is on only for as long as necessary to print each keyed-in character, and shuts off for idle periods. The depression of a keyboard key produces a signal which discharges a capacitor, whereby a motor drive transistor is rendered conductive to start the motor. A control circuit is provided,

which responds to a signal produced for each revolution of the motor and to a'clock pulse signal produced in response to a depressing operation of the keyboard to permit the passage of a character pulse synchronized with the rotation of a printer drum to thereby initiate a printing operation. After the printing operation, in the absence of a depressing operation of the keyboard, the charging of the capacitor causes the drive motor to stop, thus enabling an automatic start and stop of the motor in accordance with a depressing operation of the keyboard.

4 Claims, 2 Drawing Figures MOTOR CONTROL UNIT FOR TABLE-TYPE ELECTRONIC CALCULATOR WITI-I PRINTER BACKGROUND OF THE INVENTION The invention relates to a motor control unit for table-type electronic calculator with a printer, and more particularly to such a unit in which the start and stop of the printer driving motor is automatically controlled by a depressing operation of the keyboard.

In an apparatus having a motor, for example in a table-type electronic calculator having a printer, the usual practice of operating the motor is to provide a main switch which is turned on and stays on until manually turned off. With such an arrangement, the motor remains rotating even when the calculator is not in actual use, which causes unnecessary and undesirable noise and a temperature rise within the apparatus.

SUMMARY OF THE INVENTION An object of the invention to overcome the abovedescribed drawbacks and toprovide a motor control unit capable of reducing noise and temperature rise by activating the motor only for a given time interval following the operation of a keyboard key.

In the motor control unit according to the invention, the motor is operated for a given time interval following the operation of a keyboard key, and thus noise and temperature rise'can be substantially reduced.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF INVENTION Referring to FIG. 1, a table-type electronic calculator with a printer with which the motor control unit of the invention is associated includes a plurality of keys on a keyboard (not shown), the depression of any of which produces an input pulse train which is applied to an orcircuit OR,. For example, when one of the symbol keys of a first group on the keyboard is depressed, a clock pulse train from a clock pulse generator (not shown) is applied to the input terminal 11 of the or-circuit OR,, and when one of the symbol keys of a second group on the keyboard is depressed, a clock pulse train from the clock pulse generator is again applied to the input terminal 12 of the or-circuit OR,. If required, the orcircuit OR, may include a third input terminal 13 to which a clock pulse train from the'clock pulse generator may be applied when any one of the numeral keys on the keyboard is depressed. The output terminal of the or-circuit OR is connected with the both input terminals of and-circuit AND,, the output terminal of which is connected to the base of an NPN transistor TR, through a resistor R,. The transistor TR, has its collector grounded at GND through a resistor R and also connected to the cathode of a diode D, and has its emitter connected with a negative d.c. supply V The anode of the diode D is connected with the junction A between a resistor R and a capacitor C, which constitute an integrating circuit connected in series between the negative d.c. supply and ground. The junction A is connected with the input terminal of an inverter INV,. When a numeral key is depressed, a pulse train as shown in FIG. 2 (a) is applied through the orcircuit OR, and and-circuit AND, to the base of the transistor TR,, which therefore conducts. As a result, the capacitor C is short-circuited through the diode D and transistor TR,,and the charge thereon is instantaneously discharged to bring the potential at A to a low potential level shown in FIG. 2 (c). This results in a high potential output from the inverter INV,, which is applied through an or-circuit OR, and an inverter INV, to the base of a PNP transistor TR thereby rendering PNP transistors TR, and TR, conductive to cause a dc. motor M to rotate during the high level signal shown in FIG. 2 (b). The transistor TR and TR;, constitute a drive circuit for the dc. motor M. The base of the transistor TR is connected through a resistor R to the output terminal of the inverter IN V, and grounded through a resistor R The emitter and collector of the transistor TR are connected with the base and collector, respectively, of the transistor TR which has its emitter grounded and its collector connected to a negative d.c. supply V through the dc. motor M. The dc. motor M represents the drive source for a printer (not shown) contained in the table-type electronic calculator with which the motor control unit of the invention is associated. The dc. motor M is associatedwith a home pulsegenerator G which produces a pulse for every revolution of the motor. The pulse train from this pulse generator G-is shown as a home pulse train in FIG. 2 (d), which is applied to a flipflop circuit F,. The application of a clock pulse from a suitable clockpulse generator (not shown) causes the flipflop circuit F, to be set when the home pulse is applied, and causes the flipflop circuit to be reset when the home pulse is not applied. The output of the flipflop circuit F, is applied to a flipflop circuit F together with the clock pulse from the clock pulse generator. Upon application of'a clock pulse thereto, the flipflop circuit F is set when the flipflop circuit F, is set, and is reset when the flipflop circuit F, is reset. The output of the flipflop circuit F, is also applied to an inverter INV the output of which is applied to an or-circuitOR together with the output from the flipflop circuit F and the clock pulse from the clock pulse generator. The or-circuit 0R produces a pulse train, shown in FIG. 2 (e), which is in synchronism with the home pulse train. The outputs from the flipflop circuit F, and inverter INV, are applied to an and-circuit AND the output of which is applied to a flipflop circuit F together with the output from the or-circuit OR;,. The application of the output from the or-circuit 0R to the flipflop circuit F results in this flipflop circuit F, being set when the output from the and-circuit AND is applied thereto, and results in the circuit F being reset when the output from the andcircuit AND is not applied thereto.

The transistor TR, is rendered non-conductive when the input signal occurring as a result of a depressing operation of the keyboard ceases, and hence the capacitor C commences charging to the level of the supply voltage through the resistor R As shown in FIG. 2 (c), the voltage on the capacitor Creturns to its normal level over a preset time interval after the operation of the keyboard, and the output of the inverter INV, is applied to the and-circuit AND, during such interval. As

a result, the flipflop circuit F is set in synchronism with a first home pulse as shown in FIG. 2 (f), and its output is applied to a flipflop circuit F together with the output from the or-circuit OR;,. The application of the output from the or-circuit OR;, to the flipflop circuit F causes the circuit F to be set when the flipflop circuit F is set and causes the circuit F, to be reset when the flipflop circuit F is reset. Therefore, the flipflop circuit F is set in synchronism with a second home pulse as shown in FIG. 2 (g), and its output is applied to a flipflop circuit F together with the output from the orcircuit R The application of the output from the orcircuit 0R to the flipflop circuit F causes the circuit F to be set when the flipflop circuit F is set and causes the circuit F to be reset when the flipflop circuit F is reset. As a consequence, the flipflop circuit F is set in synchronism with a third home pulse as shown in FIG..

2 (h), and its output is applied to the or-circuit CR and and-circuits AND; and AND To the and-circuit AND is applied a signal as shown in FIG. 2 (i), a so-called character pulse train, which is synchronised with the signal produced in response to the depression of a numeral key or a symbol key. The and-circuit AND produces a pulse train of the type shown in FIG. 2 (j), which pulse train is applied to an arithmetic unit (not shown) within the table-type electronic calculator to initiate the operation of a printer contained therein. Subsequently, when the dc. motor M is in the state of steady state rotation, the printer is operated every time a key is depressed to effect a printing operation thereof. The capacitor C is short-circuited by the transistor TR every time a key on the keyboard is operated, thereby being instantaneously discharged to commence recharging. The time period from the short circuiting of the capacitor C until its charging is substantially complete depends on the values of the capacitor C and resistor R When the keyboard is operated at a time interval less than such time period, the output from the inverter INV, is at a high level as shown in FIG. 2 (b), so that the dc. motor M continues its steady state rotation and the pulse from the and-circuit AND places the table-type electronic calculator in an operative condition. When the keyboard ceases to be operated and the charging of the capacitor C is substantially complete, the output from the inverter INV changeS to a low level as shown in FIG. 2 (b), whereby the output from theand-circuit AND ceases. Subsequently, when an output pulse is produced from the or-circuit OR;, in synchronism with the home pulse train, the flipflop circuit F is reset as shown in FIG. 2 (f). When another output pulse is produced by the or-circuit 0R subsequent to the resetting of the flipflop circuit F the flipflop circuit F is reset as shown in FIG. 2 (g). When a further output pulse is produced by the or-circuit 0R subsequent to the resetting of the flipflop circuit F the flipflop circuit F is reset as shown in FIG. 2 (h). When the flipflop circuit F is reset, the transistors TR and TR;, are rendered non-conductive to interrupt the drive of the dc. motor M as shown in FIG. 2 (k), and also the output from the and-circuit AND ceases, as shown in FIG. 2 (j), to make the table-type electronic calculator inoperative. A signal PF which is produced when a suitable paper feed switch (not shown) is manually operated is applied to the and-circuit AND, and or-circuit 0R This results in producing an output from the andcircuit AND, in the similar manner as when the tabletype electronic calculator is operated or when a symbol key is depressed, which pulse is applied to the paper feed mechanism (not shown) of the printer to feed a record paper. The waveform shown in FIG. 2 (k represents the waveform of a drive voltage for the motor.

In this manner, with the arrangement according to the invention, the motor which drives the printer is started in response to a signal produced upon depression of a key on the keyboard, and the motor is stopped upon termination of the operation of the keyboard by automatically resetting the motor drive circuit with the home pulse train, so that the motor driving the printer is driven only for a given time interval which is necessary for the printing operation. This permits noises and temperature rise resulting from the motor operation to be substantially reduced.

While in certain prior art devices the motor is started by the operation ofa key and is stopped in response to each step feed of the record paper, such an arrangement requires an unalterably intermittent operation of the motor. By contrast, the invention provides for integration of the signals produced in response to the operation of keys, by an integrating circuit the output of which activates the motor, thus providing either intermittent or continuous operation of the motor depending on how fast the keys are struck, and providing a simple and inexpensive arrangement assuring a long life.

It should be understood that the invention is not limited to table-type electronic calculators, but is equally applicable to any apparatus having a motor. The number of flipflop circuits F to F, can be suitably chosen depending on the performance of the motor.

What is claimed is:

1. A motor control unit for a table-type electronic calculator with a printer and a keyboard providing character pulse trains in response to the operation of a keyboard key, said unit comprising: an integrating circuit including a capacitor which is discharged by a signal produced in response to the operation of a key on the keyboard and means for charging the capacitor at a defined rate, an electric motor for driving the printer, a drive circuit rendered conductive upon discharge of the capacitor for starting the motor, means for providing a home pulse for each revolution of the motor and a clock pulse train upon the operation of a keyboard key, a control circuit including means for providing an output signal in response to a defined home pulse and a clock pulse train and means for allowing the passage of said character pulse train to the printer during said output signal, said printer including means responding to the output signal from the control circuit to start a printing operation, means for resetting the control circuit upon the charging of the capacitor in the absence of an operation of the key, and means for interrupting the drive circuit to thereby stop the motor in response to said resetting of the control circuit.

2. A device including a printer, a keyboard, means for generating a key signal in response to the operation of each of a plurality of keyboard keys and for generating a character pulse train corresponding to the operated key, and a motor for driving the printer,

wherein the improvment is in a motor control unit comprising:

means for starting the motor in response to said key signal generated in response to the operation of a keyboard key;

means for generating a train of home pulses synchronized with the motor revolutions; control means connecting the character pulse generating means and the printer and responsive to said home pulse train for applying the character pulse train corresponding to the operated key to the printer in synchronism with a time period starting with a first selected pulse of said home pulse train and ending with a subsequent second selected home pulse; and means for stopping the motor in response to said subsequent selected home pulse. 3. A device as in claim 2 wherein the first selected home pulse is the N-th home pulse after the motor is started and the second selected home pulse is M home pulses after the first selected home pulse, where N and M are integers of selected values.

4. A device as in claim 2 wherein the control means comprise:

means responsive to the key signal to provide an enabling signal of a defined duration; means for counting the home pulses after the start of the enabling signal and for selecting the N-th pulse of its count as said first selected home pulse; and means for counting the home pulses after the end of the said enabling signal and for selecting the M-th pulse of its count as said second selected home pulse.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2665792 *Oct 27, 1950Jan 12, 1954IbmTypewriting machine having automatic cutoff switch
US2802163 *Jan 27, 1955Aug 6, 1957Royal Mcbee CorpOperation controlling mechanism for electric motor operated typewriting or like machines
US2919781 *Sep 9, 1957Jan 5, 1960Olympia Werke AgControl mechanism for the motor of an electric typewriter
US3354372 *Mar 16, 1965Nov 21, 1967Beasley Jack ODelay-responsive shut-off device for operationally-vibrating electric equipment
US3700087 *Jul 27, 1970Oct 24, 1972Singer CoPawl actuator and locking mechanism for impact contact keyboard
US3753004 *Jun 16, 1971Aug 14, 1973Custom Electronic Devices IncElectric typewriter automatic on-off switch
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4557615 *May 23, 1985Dec 10, 1985Brother Kogyo Kabushiki KaishaElectronic typewriter with automatic power-off device
US4740096 *Nov 13, 1986Apr 26, 1988Sharp Kabushiki KaishaElectronic apparatus equipped with power-saving printer
US5501534 *Oct 6, 1994Mar 26, 1996Canon Kabushiki KaishaElectronic apparatus which is automatically initialized when normal operation is resumed after the apparatus has been in a low power consumption mode
US7516450Sep 23, 2003Apr 7, 2009Ricoh Company, Ltd.Remote management system, intermediary apparatus therefor, and method of updating software in the intermediary apparatus
WO1988000137A1 *Jul 2, 1987Jan 14, 1988Jay A CrewsKeyboard
Classifications
U.S. Classification400/54, 400/479.1, 235/433
International ClassificationG06K15/00, B41J29/387, G06F15/02, H02P3/06, H02P3/08
Cooperative ClassificationB41J29/387
European ClassificationB41J29/387