US3851323A - Device for detecting the absence of a finger in a type carrier of a printer - Google Patents

Device for detecting the absence of a finger in a type carrier of a printer Download PDF

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Publication number
US3851323A
US3851323A US00362726A US36272673A US3851323A US 3851323 A US3851323 A US 3851323A US 00362726 A US00362726 A US 00362726A US 36272673 A US36272673 A US 36272673A US 3851323 A US3851323 A US 3851323A
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Prior art keywords
circuit
finger
pulse
detector
flip
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US00362726A
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English (en)
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J Eltgen
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Bull SA
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Bull SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J9/00—Hammer-impression mechanisms
    • B41J9/14—Means for selecting or suppressing individual hammers

Definitions

  • a device for detecting the absence of a finger in a printer, comprising a mobile support provided with print-type support-fingers and with an equal number of synchronization marks, and a fixed detector of synchronization marks which sends a socalled synchronization pulse to a strike triggering member, whenever a mark is passing before it.
  • the device is characterized in that it comprises a second fixed detector placed at the lever of the finger associated with the mark, which, during the displacement, passes before the first detector and delivers a pulse indicating the presence of a finger each time a finger is passing before it, and a two input recognition circuit,
  • each input receiving respectively pulses delivered by v the first and the second detector.
  • the present invention concerns a device for the detection of the absence of a finger, intended particularly for a type support for a printer having print-type carrier -fingers.
  • Such a belt is, for example, described in the French Pat. No. 1,602,392.
  • This belt is metallic, made of steel, and mounted stretched over two pulleys of parallel rotating axes. It is equipped on its upper rim with N type-carrying fingers in the form of elastic tongues which correspond to an integer number of identical sets of different characters.
  • these type-support fingers pass horizontally in a uniform linear movement before the writing medium and a striking assembly including striking motors each of which is capable of sequentially applying strike pulses to the characters by means ofa striking hammer.
  • this belt On its lower rim, this belt possesses N aligned synchronization holes, such that each of these holes is associated with a single one of the N characters.
  • a first pickup (magnetic or opticelectronic) is associated with the group of N aligned holes and connected to the frame of the printer. This pickup emits a signal each time that a hole and consequently a character passes before it. This signal is amplified, given the proper form and sent to the logic of the printer.
  • a second pickup linked to the frame of the printer is associated with the initial belt hole. It emits a signal each time that the latter passes before it. This signal, amplified and given proper form, is also sent to the logic of the printer.
  • the combination of the signal emitted by the second pickup and of the assembly of N signals transmitted by the first pickup permits the exact tracing of each character, i.e., that one always knows which of the type-supporting fingers it is that passes before a particular hammer, or more exactly, the synchronization hole corresponding with that typesupporting finger, but one does not know if that finger is physically present.
  • the probability that the finger is absent, either due to destruction or deformation is not nil, as will be explained hereinafter.
  • Printers with type-support belts exhibit the following characteristic.
  • the character-carrying finger deforms to enable the character -to remain facing the corresponding printing position as long as the impact of said hammer lasts.
  • the present invention provides a remedy for the mentioned drawbacks, by verifying that for each synchronization hole the corresponding finger is indeed present.
  • the object of the invention is a device for the detection of the absence of a finger for the character support, of printers with type-carrying fingers.
  • the invention applies to printers comprising, on the one hand, a movable support equipped with print-type carrying fingers and synchronization marks in equal number, each mark being associated with a finger, and on the other hand, a fixed detector for the synchronization marks, placed close to the path followed by said marks, this detector sending a pulse of so-called synchronization to a strike-triggering member whenever a mark is passing before it, and the invention concerns a device for the detection of the absence of fingers, characterized in that it comprises a second fixed detector close to the path followed by the fingers and positioned on the level of the finger associated with the mark which during the movement passes before the first detector, this second detector emitting a pulse signailing the presence of a finger, whenever Bennettger passes in front of it, and a recognition circuit with two inputs, each of which receive the pulses emitted by the first and by the second detector, respectively. This circuit verifies the correspondence between the pulses emitted by the two detectors and generates in its output a signal indicating the absence of a finger, if
  • the recognition circuit comprises a first and a second monostable circuit in series, a front-recognition circuit, a flip-flop circuit and a comparison circuit.
  • the first monostable circuit receives the synchronization pulse and emits, in response thereto, a first pulse, sent, on the one hand, to the second monostable circuit and, on the other hand, to the front-recognition circuit,
  • the second monostable emits, in response to that first pulse, a pulse called a window pulse, which is transmitted to the first input of the comparison circuit.
  • the recognition circuit emits, in response to that first pulse, a signal sent to the first input of said flip-flop circuit whose second input receives the pulse, signalling the presence of a finger, the signal transmitted to the first input placing the flip-flop into its first state of equilibrium, and the pulse indicating the presence of a finger, placing it into the second state of equilibrium.
  • the output signal received in the output of the said flip-flop circuit being sent to the second input of the comparison circuit which verifies if the same flip-flop circuit is not in its first state of equilibrium beyond the time interval defined by said window.
  • the first detector is preferably formed by the association comprised of a magnetic pickup of variable reluctance whose output signal is amplified and put in proper form by an amplifier circuit.
  • the second detector is identical with the first.
  • the second detector consists of the associated of an opticelectronic pickup comprising a light emitter and a photosensitive detector, also a circuit for amplification and proper forming of the output signal of said opticelectronic pickup.
  • the invention applies more particularly to endless print-type carrying belts which are mounted stretched over two pulleys of parallel rotating axes.
  • FIG. la is a perspective view of the type-carrying belt with its synchronization holes and the corresponding pickups;
  • FIGS. 1b land 2 are enlarged partial views of FIG. la;
  • FIG. 3 presents the general principle of the embodiment of the detection according to the invention.
  • FIG. 4 exhibits a type of design of the detection device whose general principle is represented by FIG. 3;
  • FIG. 5 is a chronomgram of signals taken at different points of the detection device.
  • the device for the detection of a defective finger is designed to track down any possible defectiveness of any one of the type-carrying fingers of the endless belt 1 for a printer, as shown in perspective view in FIG. la.
  • This endless belt made of a metallic material, is represented as mounted in the printing machine over two pulleys 2 and 3 whose rotational axes Y, Y, and Y Y' are vertical.
  • FIG. 1 only one portion 4 ofthe belt I has been illustrated with its typecarrying fingers 5 to 8.
  • the belt includes in all, N character-supporting fingers which correspond with an integer number of identical sets of different characters.
  • N 480 which corresponds with sets of 48 characters or 8 sets of 60 characters each. Facing the fingers 5 to 8 four striking hammers 9 to 12 are represented, denoted by arrows.
  • Four synchronization holes 13 to 16 are associated with the fingers 5 to 8, respectively. Only a single synchronization hole is associated with each finger. It should also be noted that the synchronization holes are aligned.
  • FIG. 1b which is an enlarged view of the portion 4 of the belt 1, the synchronization holes are positioned between the type-carrying fingers; thus the hole 14 is located between the fingers 5 and 6, the hole 15 between the fingers 6 and 7 etc.
  • the hole 13 is associated with the finger 5, the hole 14 with the finger 6, the hole 15 with the finger 7, and so forth.
  • the type-carrying belt 1 furthermore comprises a special synchronization hole 17, called an initial belt hole.
  • This hole is located at a level different from the alignment of the synchronization holes.
  • four supplementary synchronization holes 18 to 21 have been represented below the initial belt hole 17.
  • a pickup C With the row of N synchronization holes there is associated a pickup C,, called synchronization," connected to the frame of the printer and positioned in the immediate vicinity of the path followed by the N holes.
  • This pickup is symbolized in FIG. 1 by an arrow.
  • This may be a magnetic pickup with variable reluctance or an optic-electronic pickup. It emits a pulse whenever one of the synchronization holes passes before it. This pulse, amplified and put in proper form, is transmitted to the logic of the printer.
  • a pickup C identical with C is associated with the initial belt hole 17.
  • This pickup C emits a pulse which, after amplification, is sent to the logic of the printer.
  • these arrows denote the directions in which the pickups operate. The latter may be located on both sides of the charactersupporting belt 1.
  • the combination of the signal sent by the second pickup C and of the signals emitted by the first pickup C permits in a known manner the tracing by said logic of every one of the synchronization holes, and consequently, of every one of the N fingers, provided however, that none of these has been subjected to a deterioration (breaking, deformation).
  • the previously described assembly i.e., the N synchronization holes, the initial belt hole 17, the pickups C, and C and their corresponding amplifiers, does not provide the knowledge as to whether the N fingers are indeed present.
  • the printer strike logic does not know it and may continue to give orders to strike it.
  • a third pickup C as shown in FIG. 2 is provided, called a finger pickup," which is identical with C, and C on the level of the typesupporting fingers.
  • This pickup is linked with the frame of the printer and placed in the immediate vicinity of the path followed by these fingers.
  • the pickup C is positioned above the pickup C, (see FIG. 2) on the same vertical line.
  • the part (4) OF the type-carrying belt 1 is represented in FIG. 2 with its fingers 5 to 8 and the corresponding synchronization holes 13 to 16.
  • the synchronization pickup C is also illustrated.
  • a circuit 30 for the detection of a finger is associated with the pickups C, and C
  • This circuit 30 includes the amplifiers 31 and 32 associated with the pickups C, and C, respectively, the recognition device 33 and the alarm device 34.
  • the synchronization pickup C delivers, at the passage ofeach synchronization hole, a signal which is amplified, and put in proper form by the amplifier 31.
  • the finger pickup C emits, at the passage of each finger, a signal which is applied and put into proper form by the amplifier 32, which emits a pulse CD that is transmitted to the second input of the recognition circuit 33.
  • the recognition circuit 33 ascertains that for every pulse CS, corresponding with a determined synchronization hole, there does exist a with the finger associated with that hole.
  • the recognition circuit 33 is shown in greater detail in FIG. 4. It includes a first monostable circuit 35, a second monostable circuit 36, a recognition circuit of ascending front 37, a flip-flop 38, and a comparison circuit 39.
  • the amplifiers 31 and 32 are also represented in the same illustration.
  • the operation of the recognition circuit 33 is illustrated in FIG. 5 by the chronogram of signals taken at the output of different parts making up the recognition circuit 33 and of the amplifiers 31 and 32.
  • 1, was taken as initial time, the instant in which a certain synchronization hole, for example, the hole 13, (see FIG. 2) passes in front of the synchronization pickup C,.
  • the amplifier 31 emits a pulse CS equal to logic I between the instants 1,, and 1,.
  • This pulse CS is transmitted to the input of the first monostable 35 and triggers the latter at the instant t
  • the monostable 35 whose output signal M, before the instant 1,, was equal to logic 1 drops to zero logic at the instant 1, and rises again to logic I at the instant 1 with 1 1,.
  • the signal M is sent, on the one hand, to the input of the secpulse CD corresponding 0nd monostable 36 and, on the other hand, to the input of the recognition circuit of the ascending front 27. At the instant t in which the signal M, rises again, the monostable 36 is locked.
  • This monostable 36 whose output signal F, before the instant 1 was equal to logic I, then drops to logic zero at the instant t to ascend again, thereafter, to logic I at the instant 1, with 1, 1 T;.
  • the part of the signal during which the signal F is equal to logic zero is called the window F,.
  • the signals M, between the instants 1,, and 1 1' 1",, and 1" etc. the signals F, between the instants 1 and t 1' and t.,, 1" and 1", (windows F1, F2, F3).
  • the monostables 35 and 36 are so arranged that the instants 1 1' 1",,, centers of the successive windows F,, F F are such as:
  • the second monostable 36 permits the adjustment of the width T of the windows F,, F F etc. to a correct value by keeping in mind the accepted tolerances for the positions of the fingers. If the first case (finger 9 present) is considered, the pulse CD is located in the interior of the window F,. This pulse is a negative one which drops to logic zero at the instant 1 to rise again to logic I at the instant 1,, with 1, 1 1, and 1, 1,, 1, (see FIG. 5e). At the moment at which the window F, is generated (instant I the recognition circuit of the ascending front 37 causes the flip-flop 38 (state I) to rise. In the output Q of that flip-flop, the signal B is received which is sent to the second input ofthe comparison circuit 39.
  • This signal B which rises to logic I at the :instant 1 drops again to logic zero at the instant 1 in which the pulse CD appears (flip-flop 38) at the zero state. It may be seen then, that when a finger is present, the output of the flip-flop is reduced to' zero before the closing of the window F, (instant 1,).
  • NOT-AND circuit 40 (more commonly called NAND according to the Anglo-Saxon terminology) and an inverter 41.
  • the pulse CD appears at the instant 1' 1,.
  • the signal B is equal to logic 1 up to that moment 1' As between the instants 1, and 1' the signal F is equal 7 to logic I in the output of the AND circuit 39 a signal ALARM F.B equal to logic I (see FIG. 5f) is received between these instants.
  • the third case (finger ll absent) will be considered.
  • the signal CD does not appear, the flip-flop 38 remains in the state I, and the signal B remains equal to logic 1 until a new pulse CD appears corresponding to the passage of the present following finger. Since,
  • the device for the detection of a defective finger may be utilized for enhancing the readiness of the printing machine. For, when an ALARM signal appears, and if the logic of the printer is so conceived as to store the number of the defective finger (this is easy since the printing is controlled by a counter reduced to zero at the start of the belt by the signal of the pickup C and increased by l at each passage of a synchronization hole) the printing may be continued in a reduced manner due to a logical inhibiting of the defective finger by preventing the continued striking of this finger by the hammers.
  • the invention is by no means limited to a print-type carrying endless belt. It may equally well be applied to a printer, called daisy printer, in which the type-carrying fingers are arranged in the form of a fan, like the petals of a daisy.
  • a device for the detection of the displacement of a finger for a printer comprising a movable support in the form of an endless band carrying print-typecarrying fingers subject to deformation relative thereto and synchronization marks in equal number, each mark being associated with one finger, and a first fixed detector for the synchronization marks positioned close to the path followed by said synchronization marks; said first detector having means for sending a synchronization pulse whenever a synchronization mark passes before it; a second fixed detector positioned close to the path followed by the fingers and on the level of the finger associated with the mark that passes before the first detector, said second detector having means for emitting a pulse indicative of the presence of a finger whenever a finger passes before it, and a recognition circuit having two inputs for receiving the pulses emitted by the first and the second detector, respectively, said circuit having an output and means for verifying the correspondence between the pulses emitted by the two detectors and generating at said output a signal indicating the displacement of a finger whenever the correspondence is not established.
  • the recognition circuit verifying means includes a first and a second monostable circuit in series, a front-recognition circuit, a flip-flop circuit having first and second inputs and an output Q and a comparison circuit having first and second inputs, the first monostable circuit having means for receiving the synchronization pulse and sending in response thereto a first pulse to the second monostable circuit and to the front-recognition circuit, the second monostable having means for delivering in response to the first pulse a window pulse to the first input of the comparison circuit, the front-recognition circuit having means for sending in response to that same first pulse a signal to the first input of said flipflop circuit, means for delivering to the second input of said flip-flop circuit the pulse indicative of the presence of the finger, the flip-flop circuit being of a construction wherein the signal transmitted to the flip-flop circuit first input puts the flip-flop circuit in a first state of equilibrium and the pulse indicative of the presence of a finger puts the flip-flop circuit in the second state of equilibrium
  • a device in which the first detector includes a magnetic pickup of variable reluctance and a circuit for the amplification and forming of signals.
  • the second detector includes a magnetic pickup of variable reluctance and a circuit for the amplification and forming of signals.
  • the second detector includes the optic-electric pick-up including a light emitter and a photosensitive detector and a circuit for the amplification and forming of signals.
  • a device in which two pulleys of parallel rotational axes support the endless band.

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  • Accessory Devices And Overall Control Thereof (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
US00362726A 1972-05-25 1973-05-22 Device for detecting the absence of a finger in a type carrier of a printer Expired - Lifetime US3851323A (en)

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FR7218665A FR2185966A5 (pt) 1972-05-25 1972-05-25

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US (1) US3851323A (pt)
JP (1) JPS5527396B2 (pt)
BR (1) BR7303584D0 (pt)
DE (1) DE2326805A1 (pt)
FR (1) FR2185966A5 (pt)
GB (1) GB1432250A (pt)
IT (1) IT987895B (pt)
NL (1) NL7306864A (pt)
SU (1) SU542458A3 (pt)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4020655A (en) * 1975-01-22 1977-05-03 Centre Technique Industriel Dit: Institut Textile De France Device for detecting defects in needles on a knitting loom which is in operation
US4066969A (en) * 1975-09-22 1978-01-03 Eastman Kodak Company Multiple sheet detecting apparatus
US4106005A (en) * 1976-05-14 1978-08-08 Nippon Konbeya Kabushiki Kaisha Apparatus for detecting elongation of a joint of a conveyor belt
US4120196A (en) * 1977-03-25 1978-10-17 The Charles Stark Draper Laboratory, Inc. Production tool wear detector
US4357754A (en) * 1981-03-19 1982-11-09 Western Electric Company, Inc. Apparatus for ascertaining internal dimensions of a hollow article
US4412212A (en) * 1981-08-10 1983-10-25 Deere & Company Shearbar clearance detector

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3370286A (en) * 1964-05-12 1968-02-20 Olympia Werke Ag Apparatus for monitoring the feeding of tapelike record carriers
US3656426A (en) * 1969-05-08 1972-04-18 Potter Instrument Co Inc Apparatus for printing alphanumeric and binary code markings and comparison means therefor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3370286A (en) * 1964-05-12 1968-02-20 Olympia Werke Ag Apparatus for monitoring the feeding of tapelike record carriers
US3656426A (en) * 1969-05-08 1972-04-18 Potter Instrument Co Inc Apparatus for printing alphanumeric and binary code markings and comparison means therefor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4020655A (en) * 1975-01-22 1977-05-03 Centre Technique Industriel Dit: Institut Textile De France Device for detecting defects in needles on a knitting loom which is in operation
US4066969A (en) * 1975-09-22 1978-01-03 Eastman Kodak Company Multiple sheet detecting apparatus
US4106005A (en) * 1976-05-14 1978-08-08 Nippon Konbeya Kabushiki Kaisha Apparatus for detecting elongation of a joint of a conveyor belt
US4120196A (en) * 1977-03-25 1978-10-17 The Charles Stark Draper Laboratory, Inc. Production tool wear detector
US4357754A (en) * 1981-03-19 1982-11-09 Western Electric Company, Inc. Apparatus for ascertaining internal dimensions of a hollow article
US4412212A (en) * 1981-08-10 1983-10-25 Deere & Company Shearbar clearance detector

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JPS5012932A (pt) 1975-02-10
NL7306864A (pt) 1973-11-27
DE2326805A1 (de) 1973-12-06
BR7303584D0 (pt) 1974-07-25
IT987895B (it) 1975-03-20
SU542458A3 (ru) 1977-01-05
FR2185966A5 (pt) 1974-01-04
GB1432250A (en) 1976-04-14
JPS5527396B2 (pt) 1980-07-19

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