EP0477425A1 - Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre - Google Patents

Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre Download PDF

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Publication number
EP0477425A1
EP0477425A1 EP90118722A EP90118722A EP0477425A1 EP 0477425 A1 EP0477425 A1 EP 0477425A1 EP 90118722 A EP90118722 A EP 90118722A EP 90118722 A EP90118722 A EP 90118722A EP 0477425 A1 EP0477425 A1 EP 0477425A1
Authority
EP
European Patent Office
Prior art keywords
ink
ink liquid
writing
change
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90118722A
Other languages
German (de)
English (en)
Inventor
Josef Pöppel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Siemens AG
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Eastman Kodak Co filed Critical Siemens AG
Priority to EP90118722A priority Critical patent/EP0477425A1/fr
Publication of EP0477425A1 publication Critical patent/EP0477425A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/17—Ink jet characterised by ink handling
    • B41J2/19—Ink jet characterised by ink handling for removing air bubbles
    • 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
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2002/14354—Sensor in each pressure chamber

Definitions

  • the invention relates to a method and a device for monitoring ink liquid in writing mechanisms of ink writing devices according to the features of claims 1 and 8.
  • ink writing devices For the practical use of ink writing devices, monitoring the ink supply, especially timely detection of the ink end, plays a major role. If the ink supply is exhausted or there is air in the writing channels due to a shock, some of the nozzles or the entire writing mechanism will fail.
  • mechanical and optical monitoring systems e.g. DE-A-35 29 805
  • monitoring measures based on the measurement and evaluation of electrical quantities have become known.
  • the latter include ink monitoring systems which detect a change in the fill level in the ink reservoir via the change in capacity (IBM, TDB, Vol. 16, No. 3, Aug. 1973, p. 775) or the resistance.
  • IBM, TDB change in capacity
  • the ink end can be indicated optically and / or acoustically and cause the operator to replace the ink container or, if the ink container and the writing head form a unit, to replace this unit.
  • a device for monitoring the ink supply in ink writing devices in which an ink-specific comparative resistance and a resistance which changes as a function of the liquid level is detected with the aid of three electrodes arranged in an ink supply container. Direct current pulses with an inverted sign are applied to two of the three electrodes. A voltage corresponding to the fill level of the ink reservoir can be tapped off at the third electrode and is used as a criterion for activating a display device indicating the end of the ink reservoir and / or for switching off the ink writing device.
  • This storage container has an electronic storage device in the form of a chip, in which information about the current filling status of the storage container and / or other status data relevant for printing operation, e.g. Print media expiration dates (such as ink) are stored.
  • the state of consumption of the printing medium is recorded and communicated to the chip via a central control of the printing device.
  • the chip on the storage container counts the consumption until the supply of pressure medium is exhausted to such an extent that the storage container must be replaced.
  • bubble jet In writing units that work according to the thermal converter principle (bubble jet) and are described, for example, in DE-OS 30 12 698, monitoring the presence of ink liquid is of great importance not only in the storage container but also on the converter element.
  • These bubble jet ink heads have a large number of individual nozzles, from which defined individual droplets are ejected under the action of an electronic control.
  • a characteristic feature of this technology is that an electrical resistor designed as a heating element is located in a capillary filled with ink liquid, in the vicinity of its opening, which is referred to as the nozzle.
  • an impact can suck air into the nozzle and displace the ink liquid over the heating element. If one wanted to recognize this via two measuring contacts, then at least one additional line would have to be provided for each heating element.
  • the contacts are exposed to considerable chemical and thermal stress (typical temperatures approx. 300 ° C) that they come into direct contact with the hot ink liquid.
  • the additional lines would also have to be contacted and connected to the control electronics during the manufacture of the writing mechanism, which would mean an increased outlay.
  • the object of the invention is now to specify an ink monitor for ink writing devices of the type mentioned at the beginning, with which the presence of ink liquid can be monitored directly at the actuators of the ink writing mechanism and which does not require any additional electrical lines on the actuator.
  • the invention is based on the knowledge that the change in the electrical current through an electrothermal transducer element (bubble jet heating element) according to a resistance temperature measurement method can be used to determine whether there is ink liquid above the heating element or not, based on the temperature dependence of the heating element resistance. If the ink writing device is operated without ink liquid, the heating process takes place more quickly since less thermal mass has to be heated. This effect in turn can be recognized from an increased current change rate corresponding to the higher heating rate. On the other hand, evaporation occurs when operating with ink liquid, which leads to an interruption in the heat transport into the ink liquid. From this point on, the heating element heats up faster, which can be sensed as a change in the current change rate in the heating element.
  • the electrothermal transducer elements are used not only as actuators but also as sensors.
  • the electrical resistance of the transducer elements also changes with temperature due to the resistance temperature coefficients.
  • the electrical resistance increases or decreases.
  • Common transducer elements made of a thin layer of hafnium diboride have a negative temperature coefficient. Based on the change in the electrical current through the transducer element, it can be recognized in accordance with a resistance temperature measurement method based on this temperature dependence of the electrical resistance of the transducer elements whether or not there is ink liquid on the transducer element. If there is no ink liquid in the ink channel above the transducer element, the heating process of the transducer element takes place more quickly since less thermal mass is to be heated. This effect can be recognized by an increased current change rate.
  • the current change signal on the electrothermal transducer element for two possible operating cases of the ink writing mechanism is shown in a qualitative representation using a measurement diagram.
  • the solid line L shows the time course of the current signal through the electrothermal transducer element during operation of the ink writing mechanism without ink liquid above the transducer element.
  • the dashed line T shows that curve of the current signal when ink liquid in the ink channel, i.e. is present above the transducer element.
  • a current pulse of 7 us is used as the drive pulse for the converter element.
  • ink liquid in the ink channel can now be detected from the slope of the current signal.
  • the slope is in a critical area, i.e. considered in a so-called time window F.
  • a weak kink can be seen here in the current change curve.
  • a differentiation circuit converts the different changes in the current signal into different levels, which are interpreted as being present or not present by the control electronics of the ink writing device.
  • FIG. 2 shows a basic circuit diagram of such a monitoring and evaluation circuit.
  • the control pulses for the electrothermal converter elements are generated from a DC supply voltage UB by means of an electronic switching device S.
  • the reference symbol RH denotes the electrical resistance of a converter element
  • RM denotes a measuring resistor.
  • a differentiation stage D consisting of a capacitor arranged in the longitudinal branch and an electrical resistor arranged in the transverse branch converts the different changes in the current signal into different levels, which are transmitted via an amplifier element V of an evaluation device K with threshold value behavior are fed.
  • An evaluation signal is thus available at its output, which in a manner not shown here in the central control device of the ink writing device leads to the issuing of a corresponding message by means of an acoustic and / or optical display device for the operator and / or to the switching off of the ink writing device.
  • the result of the current signal evaluation depends on the absolute value of the temperature coefficient of the transducer element material. Since this temperature coefficient may fluctuate in the course of the life of the converter elements, it is advantageous in the sense of a less sensitive measuring method to evaluate the change in the current change signal.
  • the curve T of the current change signal shown in dashed lines in the measurement diagram according to FIG. 1 corresponds to the curve T in FIG. 1 and shows the conditions when the ink writing mechanism is operated with ink liquid. If a slightly pronounced kink can be seen in the current change curve T (in the time window F), this is shown as a clearly pronounced minimum in the high-pass filtered signal.
  • the heat flow into the ink liquid is interrupted when the electrothermal transducer element is covered with steam .
  • the temperature of the converter element and thus the current rise more rapidly from this point in time.
  • this clearly defined minimum is also missing in the filtered current change signal.
  • a subsequent level of differentiation can easily see whether the slope changes at the minimum or whether it is missing like the ink liquid. This is largely independent of the absolute value of the temperature coefficient of the material used for the converter element.
EP90118722A 1990-09-28 1990-09-28 Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre Withdrawn EP0477425A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP90118722A EP0477425A1 (fr) 1990-09-28 1990-09-28 Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP90118722A EP0477425A1 (fr) 1990-09-28 1990-09-28 Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre

Publications (1)

Publication Number Publication Date
EP0477425A1 true EP0477425A1 (fr) 1992-04-01

Family

ID=8204549

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90118722A Withdrawn EP0477425A1 (fr) 1990-09-28 1990-09-28 Procédé et dispositif pour contrôler l'encre dans la tête d'une imprimante à jet d'encre

Country Status (1)

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EP (1) EP0477425A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1057638A3 (fr) * 1999-06-04 2001-10-17 Canon Kabushiki Kaisha Tête et appareil d'éjection de liquide
WO2023079265A1 (fr) 2021-11-03 2023-05-11 United Biscuits (Uk) Limited Améliorations apportées et se rapportant à un emballage

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3227636A1 (de) * 1981-07-28 1983-02-10 Sharp K.K., Osaka Tintenstrahldrucker
DE4009808A1 (de) * 1990-03-27 1990-08-09 Siemens Ag Anordnung zur ueberwachung des tintenvorrats und der tintenversorgung im schreibkopf einer tintendruckeinrichtung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3227636A1 (de) * 1981-07-28 1983-02-10 Sharp K.K., Osaka Tintenstrahldrucker
DE4009808A1 (de) * 1990-03-27 1990-08-09 Siemens Ag Anordnung zur ueberwachung des tintenvorrats und der tintenversorgung im schreibkopf einer tintendruckeinrichtung

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 11, no. 39 (M-559)(2486) 05 Februar 1987, & JP-A-61 206657 (YOSHIHIRO NAKAGAWA) 12 September 1986, *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 104 (M-296)(1541) 16 Mai 1984, & JP-A-59 014967 (AKIRA MIYAGAWA) 25 Januar 1984, *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1057638A3 (fr) * 1999-06-04 2001-10-17 Canon Kabushiki Kaisha Tête et appareil d'éjection de liquide
US6540316B1 (en) 1999-06-04 2003-04-01 Canon Kabushiki Kaisha Liquid discharge head and liquid discharge apparatus
US6786572B2 (en) 1999-06-04 2004-09-07 Canon Kabushiki Kaisha Liquid discharge head and liquid discharge apparatus
WO2023079265A1 (fr) 2021-11-03 2023-05-11 United Biscuits (Uk) Limited Améliorations apportées et se rapportant à un emballage

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