WO1988010192A1 - Ink printing head with tangential-feed pressure chambers - Google Patents

Ink printing head with tangential-feed pressure chambers Download PDF

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Publication number
WO1988010192A1
WO1988010192A1 PCT/DE1988/000321 DE8800321W WO8810192A1 WO 1988010192 A1 WO1988010192 A1 WO 1988010192A1 DE 8800321 W DE8800321 W DE 8800321W WO 8810192 A1 WO8810192 A1 WO 8810192A1
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WO
WIPO (PCT)
Prior art keywords
ink
pressure chambers
pressure chamber
chambers
nozzle channel
Prior art date
Application number
PCT/DE1988/000321
Other languages
German (de)
French (fr)
Inventor
Peter Külzer
Original Assignee
Siemens Aktiengesellschaft
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 Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO1988010192A1 publication Critical patent/WO1988010192A1/en

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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
    • B41J2/14201—Structure of print heads with piezoelectric elements
    • B41J2/14298—Structure of print heads with piezoelectric elements of disc type
    • 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
    • B41J2002/14387—Front shooter

Definitions

  • Ink printhead with pressure chambers having a tangential ink feed Ink printhead with pressure chambers having a tangential ink feed.
  • the invention relates to an ink print head according to the preamble of patent claim 1.
  • Piezoelectrically driven drive elements in ink printing devices are generally known.
  • DE-A28 08 407 describes an ink droplet printing device in which a liquid located in ink chambers is ejected from writing nozzles via piezoelectrically operated drive elements. The change in volume in the chamber is brought about by an electrically controlled piezoceramic which sits on a metal plate and which bulges into the chamber in the event of excitation.
  • EP-B-00 37 624 also discloses a printhead for an inkjet printing device which has a multiplicity of pressure chambers with associated electromechanical transducers.
  • the pressure chambers which are connected on one side to the outlet nozzles of the write head and on the other side to a storage container, have a substantially lenticular cross section. Such a cross section is streamlined and allows the ink to flow easily.
  • Air bubbles which have penetrated into such shaped ink chambers - for example due to outgassing of the ink - are very difficult to remove from these chambers.
  • One possibility is to apply pressure to the ink on the supply side and thus flush the pressure chambers. As a result, however, only the gas bubbles located in the center of the pressure chambers are removed; the gas bubbles which are attached to the edge are not reached by the flow in the pressure chamber or by the flow controlled so that they remain in the pressure chamber and thus significantly interfere with the control behavior of the entire printhead.
  • the object of the invention is to design an ink print head of the type mentioned in such a way that air bubbles contained in the ink can be easily removed from the ink head or the pressure chambers.
  • the pressure chamber is designed to be circular in cross-section with a centrally arranged nozzle channel and the ink is fed tangentially via the supply line to the pressure chamber in such a way that the ink flows through the pressure chambers to the nozzle channel in the manner of a spiral vortex, this surprisingly results in that ink flowing through the pressure chambers also entrains any air bubbles located at the edge of the pressure chambers. The air bubbles cannot get stuck inside the pressure chamber.
  • the nozzle channel is conical at least in the mouth region of the pressure chamber. butt-shaped. This promotes the formation of such a spiral vortex and air bubbles are particularly easily entrained.
  • the ink print head is constructed in multiple layers, it is advantageous if the nozzle channel and the pressure chamber are formed by concentrically arranged, disc-shaped recesses.
  • the ejection effect of the pressure chambers themselves can be increased in that the cross section of the supply line directly at the mouth area of the supply line into the pressure chamber is smaller than in the direction of flow of the ink in front of the mouth area.
  • FIG. 1 shows a partial sectional view of an ink print head according to the invention
  • FIG. 2 shows a horizontal sectional view of a pressure chamber of an ink print head according to FIG. 1 along the section lines II-II.
  • An ink print head for an ink print device, in which the ink print head is guided line by line along a recording medium in writing mode, is built up in layers. It contains an approximately 200 ⁇ m thick first channel plate 1, e.g. made of nickel, which receives the actual cylinder stump-like pressure chambers 2 with a diameter of approx. 1 - 1.5 mm. Also arranged in the first duct plate 1: the supply ducts 3, which open tangentially into the side wall of the pressure chambers 2 and which have a clear height of approximately 100 ⁇ m and a width of 200 ⁇ m.
  • the membrane 4 On one side of the first channel plate 1 there is a thin membrane 4 made of nickel or a chromium-nickel layer of approximately 30-50 ⁇ m thick.
  • the membrane 4 forms a contact plate for the circular piezo disks 5, which are arranged on the membrane 4 and consist of piezoelectric material and have a diameter of approximately 1 to 1.5 mm. Together with the membrane 4, the piezo disks 5 span the pressure chambers 2 and thus form a wall that can be deflected when electrically excited.
  • the piezo disks 5 are contacted via correspondingly soldered lines 6.
  • channel plates 7 and 8 are arranged, which can also consist of nickel and have a thickness of approximately 100 ⁇ m.
  • This Channel plates 7 and 8 form the nozzle channel with their central concentric openings 7/1 and 8/1.
  • the concentric openings are dimensioned so that the nozzle channel has an approximately frustoconical shape, at least in the mouth area to the pressure chamber 2.
  • the channel plate 7, which borders directly on the pressure chamber 2 has an opening of approximately 450 to 500 ⁇ m in diameter
  • the channel plate 8 has an opening of approximately 300 ⁇ m in diameter, with all the channel plates then being made through a nozzle plate 9 made of nickel of approximately 100 ⁇ m thickness are completed.
  • the actual outlet nozzles 10 of approximately 80 ⁇ m in diameter are arranged in the nozzle plate 9.
  • the supply channels 3 for the pressure chambers 2 are also arranged in the channel plates 7 and 8.
  • the supply channels are designed in such a way that the cross section of the supply lines 3 directly at the mouth area of the supply lines into the pressure chambers 2 is smaller than in the flow direction in front of the mouth area e.g. in the area of the channel plates 7 and 8. A throttling effect of the ink feed line is achieved.
  • the function of such an ink print head is as follows. With pulsed electrical excitation of the polarized piezo disk 5 with e.g. a voltage pulse of 100 volts with a positive polarity on the feed line 6, the deflectable wall of the pressure chamber 2 consisting of the piezo disk 5 and the membrane 4 is deflected and thus the ink therein is compressed and a drop is ejected via the nozzle opening 10.
  • the frequency of the droplet sequence is determined, among other things, by the layer thickness of the ink head or the effective length of the nozzle channel.
  • the exciting impulse has an influence in so far as the amplitude affects the size of the ink droplet and the rise time affects the speed of the ink droplet.
  • the ink supply 3 is designed such that it opens tangentially laterally into the pressure chamber 2.
  • the ink in the pressure chamber 2 thus forms a spiral vortex which flows through the pressure chamber 2 and the nozzle channels 7/1, 8/1 in accordance with the direction of the arrow shown and thereby entrains the air bubbles 11.
  • small amounts of ink flowing through are sufficient.
  • the supply channel opens tangentially into the side wall of the pressure chambers 2.
  • a different configuration of the pressure chamber 2 e.g. to open on the bottom or top wall.
  • Other designs and arrangements are also conceivable, but it is essential that the ink is fed in such a way that a spiral vortex forms towards the nozzle channel, which sweeps all wall surfaces with its flow, so that adhering ink bubbles are entrained and removed.
  • the function of the invention is independent of the type of transducer elements.
  • these transducer elements can be piezo disks or electronic transducer elements.
  • the dimensions are also exemplary.

Landscapes

  • Particle Formation And Scattering Control In Inkjet Printers (AREA)

Abstract

An ink printing head contains pressure chambers (2) of approximately circular cross-section. The pressure chambers (2) are supplied with ink from a storage region through feed lines (3) opening tangentially into the pressure chambers. The truncated cylinder-shaped pressure chambers have piezotransducers (5) on one side which when electrically excited bulge outwards and eject ink droplets through a central jet channel. The tangential feeding of the ink to the compression chambers (2) causes the ink to pass through the compression chambers and the region where the jet channel opens into the pressure chambers in a turbulent spiral flow, thereby entraining any gas bubbles (11) present in the pressure chambers.

Description

Tintendruckkopf mit eine tangentiale Tintenzuführung aufweisenden Druckkammern. Ink printhead with pressure chambers having a tangential ink feed.
Die Erfindung betrifft einen Tintendruckkopf gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to an ink print head according to the preamble of patent claim 1.
Piezoelektrisch angetriebene Antriebselemente in Tintendruckeinrichtungen sind allgemein bekannt. So wird in der DE-A28 08 407 eine Tintentröpfchen-Druckvorrichtung beschrieben, bei der über piezoelektrisch betriebene Antriebselemente eine in Tintenkammern befindliche Flüssigkeit aus Schreibdüεen aus gestoßen wird. Die Volumenänderung in der Kammer wird durch eine elektrisch angesteuerte Piezokeramik bewirkt, die auf einer Metallplatte sitzt und die sich im Erregungsfalle in die Kammer hineinwölbt.Piezoelectrically driven drive elements in ink printing devices are generally known. For example, DE-A28 08 407 describes an ink droplet printing device in which a liquid located in ink chambers is ejected from writing nozzles via piezoelectrically operated drive elements. The change in volume in the chamber is brought about by an electrically controlled piezoceramic which sits on a metal plate and which bulges into the chamber in the event of excitation.
Es ist weiters aus der EP-B-00 37 624 ein Druckkopf für eine Tintenstrahldruckeinrichtung bekannt, die eine Vielzahl von Druckkammern mit zugeordneten elektromechanischen Wandlern aufweist. Die Druckkammern, die auf der einen Seite mit den Austrittsdüsen des Schreibkopfes in Verbindung stehen, auf der anderen Seite mit einem Vorratsbehälter, haben im wesentlichen einen linsenförmigen Querschnitt. Ein derartiger Querschnitt ist strömungsgünstig und ermöglicht einen leichten Durchfluß der Tinte.EP-B-00 37 624 also discloses a printhead for an inkjet printing device which has a multiplicity of pressure chambers with associated electromechanical transducers. The pressure chambers, which are connected on one side to the outlet nozzles of the write head and on the other side to a storage container, have a substantially lenticular cross section. Such a cross section is streamlined and allows the ink to flow easily.
In derartig ausgeformten Tintenkammern eingedrungene Luftblasen - z.B. durch Ausgasung der Tinte - lassen sich sehr schwer aus diesen Kammern entfernen. Eine Möglichkeit besteht darin, auf der Vorratsseite Druck auf die Tinte auszuüben und so die Druckkammern durchzuspülen. Dadurch werden aber nur die sich im Zentrum der Druckkammern befindlichen Gasblasen entfernt, die sich am Rand festsetzenden Gasblasen werden von der Strömung in der Druckkammer nicht erreicht bzw. von der Strömung so gesteuert, daß sie in der Druckkammer verbleiben und damit das Ansteuerverhalten des gesamten Druckkopfes beträchtlich stören.Air bubbles which have penetrated into such shaped ink chambers - for example due to outgassing of the ink - are very difficult to remove from these chambers. One possibility is to apply pressure to the ink on the supply side and thus flush the pressure chambers. As a result, however, only the gas bubbles located in the center of the pressure chambers are removed; the gas bubbles which are attached to the edge are not reached by the flow in the pressure chamber or by the flow controlled so that they remain in the pressure chamber and thus significantly interfere with the control behavior of the entire printhead.
Um dies zu verhindern sind deswegen am Eintrittsbereich und am Austrittsbereich der Druckkammern Inseln angeordnet, die die Tintenströmung teilen und dafür sorgen, daß die Tinte entlang den Wandbereichen der Druckkammer strömt. Diese Inseln sind nun einerseits wegen ihrer Größe schwer herstellbar, andererseits bilden sie einen unerwünschten Strömungswiderstand, der sich ungünstig auf das Ansteuerverhalten der Druckkammer auswirkt.To prevent this, islands are therefore arranged at the inlet region and at the outlet region of the pressure chambers, which divide the ink flow and ensure that the ink flows along the wall regions of the pressure chamber. On the one hand, these islands are difficult to manufacture because of their size, on the other hand, they form an undesirable flow resistance, which has an unfavorable effect on the control behavior of the pressure chamber.
Aufgabe der Erfindung ist es einen Tintendruckkopf der eingangs genannten Art so auszugestalten, daß in der Tinte enthaltene Luftblasen leicht aus dem Tintenkopf bzw. den Druckkammern entfernt werden können.The object of the invention is to design an ink print head of the type mentioned in such a way that air bubbles contained in the ink can be easily removed from the ink head or the pressure chambers.
Diese Aufgabe wird bei einem Tintendruckkopf der eingangs genannten Art gemäß dem kennzeichnenden Teil des ersten Patentanspruches gelöst.This object is achieved with an ink print head of the type mentioned in the characterizing part of the first claim.
Vorteilhafte Ausführungsformen der Erfindung sind in denAdvantageous embodiments of the invention are in the
Unteransprüchen gekennzeichnet.Subclaims marked.
Gestaltet man gemäß der Erfindung die Druckkammer im Querschnitt kreisförmig mit zentral angeordnetem Düsenkanal und führt man die Tinte über die Versorgungsleitung der Druckkammer tangential derart zu, daß die Tinte die Druckkammern bis zum Düsenkanal in der Art eines Spiralwirbeis durchströmt, so ergibt sich in überraschender Weise daß die Druckkammern durchströmende Tinte auch evtl. sich am Rand der Druckkammern befindliche Luftbläschen mitreißt. Die Luftbläschen können sich innerhalb der Druckkammer nicht festsetzen.If, according to the invention, the pressure chamber is designed to be circular in cross-section with a centrally arranged nozzle channel and the ink is fed tangentially via the supply line to the pressure chamber in such a way that the ink flows through the pressure chambers to the nozzle channel in the manner of a spiral vortex, this surprisingly results in that ink flowing through the pressure chambers also entrains any air bubbles located at the edge of the pressure chambers. The air bubbles cannot get stuck inside the pressure chamber.
Bei einer vorteilhaften Ausführungsform der Erfindung ist der Düsenkanal zumindest im Mündungsbereich der Druckkammer kegel- stumpfartig ausgebildet. Damit wird die Bildung eines derartigen Spiralwirbels gefördert und Luftbläschen besonders leicht mitgerissen.In an advantageous embodiment of the invention, the nozzle channel is conical at least in the mouth region of the pressure chamber. butt-shaped. This promotes the formation of such a spiral vortex and air bubbles are particularly easily entrained.
Wird der Tintendruckkopf mehrschichtig aufgebaut, ist es von Vorteil, wenn der Düsenkanal und die Druckkammer durch konzentrisch angeordnete, scheibenförmige Ausnehmungen gebildet wird.If the ink print head is constructed in multiple layers, it is advantageous if the nozzle channel and the pressure chamber are formed by concentrically arranged, disc-shaped recesses.
Die Ausstoßwirkung der Druckkammern selbst kann dadurch erhöht werden, daß der Querschnitt der Versorgungsleitung unmittelbar am Mündungsbereich der Versorgungsleitung in die Druckkammer kleiner ist als in Strömungsrichtung der Tinte vor dem Mündungsbereich.The ejection effect of the pressure chambers themselves can be increased in that the cross section of the supply line directly at the mouth area of the supply line into the pressure chamber is smaller than in the direction of flow of the ink in front of the mouth area.
Diese ventilartige Charakteristik des Mündungsbereiches der Druckkammern erhöht deren Wirkungsgrad insgesamt. This valve-like characteristic of the mouth area of the pressure chambers increases their overall efficiency.
Eine Ausführungsform der Erfindung ist in den Zeichnungen dargestellt und wird im folgenden beispielsweise näher beschrieben. Es zeigtAn embodiment of the invention is shown in the drawings and is described in more detail below, for example. It shows
FIG 1 eine ausschnittsweise Schnittdarstellung eines Tintendruckkopfes gemäß der Erfindung und1 shows a partial sectional view of an ink print head according to the invention and
FIG 2 eine horizontale Schnittdarstellung einer Druckkammer eines Tintendruckkopfes gemäß FIG 1 entlang den Schnittlinien II-II.2 shows a horizontal sectional view of a pressure chamber of an ink print head according to FIG. 1 along the section lines II-II.
Ein hier nicht in seiner Gesamtheit dargestellter Tintendruckkopf für eine Tintendruckeinrichtung, bei der der Tintendruckkopf im Schreibbetrieb zeilenweise entlang von einem Aufzeichnungεträger geführt wird, ist schichtenweise aufgebaut. Er enthält eine etwa 200 μm starke erste Kanalplatte 1, z.B. aus Nickel, die die eigentlichen zylinderstumpfartig ausgeformten Druckkammern 2 mit einem Durchmesser von ca. 1 - 1,5 mm aufnimmt. Weiterhin sind in der ersten Kanalplatte 1 angeordnet: die Versorgungskanäle 3, die tangential in die seitliche Wandung der Druckkammern 2 münden und die eine lichte Höhe von etwa 100 μm und eine Breite von 200 μm aufweisen.An ink print head, not shown here in its entirety, for an ink print device, in which the ink print head is guided line by line along a recording medium in writing mode, is built up in layers. It contains an approximately 200 μm thick first channel plate 1, e.g. made of nickel, which receives the actual cylinder stump-like pressure chambers 2 with a diameter of approx. 1 - 1.5 mm. Also arranged in the first duct plate 1: the supply ducts 3, which open tangentially into the side wall of the pressure chambers 2 and which have a clear height of approximately 100 μm and a width of 200 μm.
Auf der einen Seite der ersten Kanalplatte 1 befindet sich eine dünne Membrane 4 aus Nickel oder einer Chromnickelschicht von ca. 30 - 50 μm Stärke. Die Membrane 4 bildet eine Kontaktplatte für die auf der Membrane 4 angeordneten kreisförmigen, aus piezoelektrischem Material bestehenden Piezoscheiben 5 von einem Durchmesser von etwa 1 bis 1,5 mm. Zusammen mit der Membrane 4 überspannen die Piezoscheiben 5 die Druckkammern 2 und bilden damit eine bei elektrischer Anregung auslenkbare Wand. Die Piezoscheiben 5 sind dabei über entsprechend angelötete Leitungen 6 kontaktiert.On one side of the first channel plate 1 there is a thin membrane 4 made of nickel or a chromium-nickel layer of approximately 30-50 μm thick. The membrane 4 forms a contact plate for the circular piezo disks 5, which are arranged on the membrane 4 and consist of piezoelectric material and have a diameter of approximately 1 to 1.5 mm. Together with the membrane 4, the piezo disks 5 span the pressure chambers 2 and thus form a wall that can be deflected when electrically excited. The piezo disks 5 are contacted via correspondingly soldered lines 6.
Auf der anderen Seite der ersten Kanalplatte 1 sind weitere Kanalplatten 7 und 8 angeordnet, die ebenfalls aus Nickel bestehen können und etwa die Stärke von 100 μm aufweisen. Diese Kanalplatten 7 und 8 bilden mit ihren zentralen konzentrischen Öffnungen 7/1 und 8/1 den Düsenkanal. Die konzentrischen Öffnungen sind dabei so bemessen, daß der Düsenkanal zumindest im Mündungsbereich zu der Druckkammer 2 eine etwa kegelstumpfartige Form hat. Zu diesem Zwecke weist die Kanalplatte 7, die unmittelbar an die Druckkammer 2 grenzt, eine Öffnung von ca. 450 bis 500 μm Durchmesser auf, die Kanalplatte 8 eine Öffnung von etwa 300 μm Durchmesser, wobei dann sämtliche Kanalplatten durch eine aus Nickel bestehende Düsenplatte 9 von etwa 100 μm Stärke abgeschlossen sind. In der Düsenplatte 9 sind die eigentlichen Austrittsdüsen 10 von etwa 80 μm Durchmesser angeordnet.On the other side of the first channel plate 1, further channel plates 7 and 8 are arranged, which can also consist of nickel and have a thickness of approximately 100 μm. This Channel plates 7 and 8 form the nozzle channel with their central concentric openings 7/1 and 8/1. The concentric openings are dimensioned so that the nozzle channel has an approximately frustoconical shape, at least in the mouth area to the pressure chamber 2. For this purpose, the channel plate 7, which borders directly on the pressure chamber 2, has an opening of approximately 450 to 500 μm in diameter, the channel plate 8 has an opening of approximately 300 μm in diameter, with all the channel plates then being made through a nozzle plate 9 made of nickel of approximately 100 μm thickness are completed. The actual outlet nozzles 10 of approximately 80 μm in diameter are arranged in the nozzle plate 9.
In den Kanalplatten 7 und 8 sind weiterhin die Versorgungskanäle 3 für die Druckkammern 2 angeordnet. Die Versorgungskanäle sind so ausgestaltet, daß der Querschnitt der Versorgungsleitungen 3 unmittelbar am Mündungsbereich der Versorgungsleitungen in die Druckkammern 2 kleiner sind als in Strömungsrichtung vor dem Mündungsbereich z.B. im Bereich der Kanalplatten 7 und 8. Damit wird eine Drosselwirkung der Tintenzuleitung erzielt.The supply channels 3 for the pressure chambers 2 are also arranged in the channel plates 7 and 8. The supply channels are designed in such a way that the cross section of the supply lines 3 directly at the mouth area of the supply lines into the pressure chambers 2 is smaller than in the flow direction in front of the mouth area e.g. in the area of the channel plates 7 and 8. A throttling effect of the ink feed line is achieved.
Die Funktion eines derartigen Tintendruckkopfes ist dabei wie folgt. Bei impulsartiger elektrischer Anregung der polarisierten Piezoscheibe 5 mit z.B. einem Spannungsimpuls von 100 Volt mit einer positiven Polarität an der Zuleitung 6, wird die aus Piezoscheibe 5 und Membrane 4 bestehende auslenkbare Wand der Druckkammer 2 ausgelenkt und damit die darin befindliche Tinte komprimiert und über die Düsenöffnung 10 ein Tropfen ausgestoßen. Die Frequenz der Tröpfchenfolge wird unter anderem bestimmt durch die Schichtstärke des Tintenkopfes bzw. der wirksamen Länge des Düsenkanales. Der erregende Impuls hat dabei insoweit einen Einfluß als sich die Amplitude auf die Größe des Tintentröpfchens auswirkt, die Anstiegszeit auf die Geschwindigkeit des Tintentröpfchens.The function of such an ink print head is as follows. With pulsed electrical excitation of the polarized piezo disk 5 with e.g. a voltage pulse of 100 volts with a positive polarity on the feed line 6, the deflectable wall of the pressure chamber 2 consisting of the piezo disk 5 and the membrane 4 is deflected and thus the ink therein is compressed and a drop is ejected via the nozzle opening 10. The frequency of the droplet sequence is determined, among other things, by the layer thickness of the ink head or the effective length of the nozzle channel. The exciting impulse has an influence in so far as the amplitude affects the size of the ink droplet and the rise time affects the speed of the ink droplet.
Sind nun gemäß der FIG 2 durch Ausgasung der Tinte oder andere Umstände Luftbläschen 11 in die Druckkammern 2 eingedrungen, so können diese Luftbläschen 11 durch Druckerhöhung auf der Vorratsseite ausgespült werden. Die Tintenzuführung 3 ist da¬bei so ausgestaltet, daß sie tangential seitlich in die Druckkammer 2 mündet. Damit bildet die Tinte in der Druckkammer 2 einen Spiralwirbel, der entsprechend der dargestellten Pfeilrichtung Druckkammer 2 und die Düsenkanäle 7/1, 8/1 durchströmt und dabei die Luftbläschen 11 mitreißt. Um diesen Spiralwirbεl zu erzeugen und die Luftbläschen aus den Druckkammern zu spülen, genügen bereits geringe Mengen von durchströmender Tinte.If, according to FIG. 2, air bubbles 11 have penetrated the pressure chambers 2 due to outgassing of the ink or other circumstances, so these air bubbles 11 can be flushed out by increasing the pressure on the supply side. The ink supply 3 is designed such that it opens tangentially laterally into the pressure chamber 2. The ink in the pressure chamber 2 thus forms a spiral vortex which flows through the pressure chamber 2 and the nozzle channels 7/1, 8/1 in accordance with the direction of the arrow shown and thereby entrains the air bubbles 11. In order to generate this spiral vortex and to flush the air bubbles out of the pressure chambers, small amounts of ink flowing through are sufficient.
Bei dem dargestellten Ausführungsbeispiel mündet der Versorgungskanal tangential in die seitliche Wandung der Druckkammern 2. Es ist jedoch auch denkbar, den Versorgungskanal bei einer entsprechend anderen Konfiguration der Druckkammer 2 z.B. an der unteren oder oberen Wandung münden zu lassen. Auch andere Ausführungen und Anordnungen sind denkbar, wesentlich ist jedoch, daß die Tinte so zugeführt wird, daß sich zum Düsenkanal hin ein Spiralwirbel bildet der mit seiner Strömung sämtliche Wandflächen bestreicht, so daß daran haftende Tintenbläschen mitgerissen und entfernt werden. Es ist außerdem darauf hinzuweisen, daß die Funktion der Erfindung von der Art der Wandlerelemente unabhängig ist. So können diese Wandlerelemente wie beschrieben Piezoscheiben sein oder auch elektronische Wandlerelemente. Auch bei den Maßangaben handelt es sich um beispielhafte Angaben. In the illustrated embodiment, the supply channel opens tangentially into the side wall of the pressure chambers 2. However, it is also conceivable to use a different configuration of the pressure chamber 2, e.g. to open on the bottom or top wall. Other designs and arrangements are also conceivable, but it is essential that the ink is fed in such a way that a spiral vortex forms towards the nozzle channel, which sweeps all wall surfaces with its flow, so that adhering ink bubbles are entrained and removed. It should also be noted that the function of the invention is independent of the type of transducer elements. Thus, as described, these transducer elements can be piezo disks or electronic transducer elements. The dimensions are also exemplary.

Claims

Patentansprüche Claims
1. Tintendruckkopf mit mindestens einer, einen etwa kreisförmigen Querschnitt aufweisenden Druckkammer (2), der über eine Versorgungsleitung (3) aus einem Vorratsbereich Tinte zugeführt wird, wobei die Druckkammer (2) Wandlerelemente (5) aufweist, derart, daß über einen Düsenkanal (10) bei elektrischer Anregung der Wandlerelemente (5) Tintentröpfchen ausgestoßen werden, d a d u r c h g e k e n n z e i c h n e t , daß die Tinte der Druckkammer (2) über die Versorgungsleitung (3) etwa tangential zur Wand derart zugeführt wird, daß die Tinte die Druckkammer (2) bis zum Düsenkanal (10) in der Art eines Spiralwirbεls durchströmt.1.Ink printhead with at least one, approximately circular cross-section pressure chamber (2) which is supplied with ink from a supply area via a supply line (3), the pressure chamber (2) having transducer elements (5), such that a nozzle channel ( 10) when the transducer elements (5) are electrically excited, droplets of ink are ejected, characterized in that the ink is supplied to the pressure chamber (2) via the supply line (3) approximately tangentially to the wall such that the ink leads the pressure chamber (2) to the nozzle channel ( 10) flows through in the manner of a spiral vortex.
2. Tintendruckkopf nach Anspruch 2, d a d u r c h g e k e n n z e i c h n e t , daß der Düsenkanal (7/1, 8/1) zumindest im Mündungsbereich zur Druckkammer (2) kegelstumpfartig ausgebildet ist.2. Ink printhead according to claim 2, so that the nozzle channel (7/1, 8/1) is frustoconical, at least in the mouth area to the pressure chamber (2).
3. Tintendruckkopf nach einem der Ansprüche 1 oder 2, d a d u r c h g e k e n n z e i c h n e t , daß die Druckkammer (2) kegelstumpfartig ausgebildet ist.3. Ink printhead according to one of claims 1 or 2, d a d u r c h g e k e n n z e i c h n e t that the pressure chamber (2) is frustoconical.
4. Tintendruckkopf nach einem der Ansprüche 1 bis 3, d a d u r c h g e k e n n z e i c h n e t , daß der Querschnitt der Versorgungsleitung (3) unmittelbar am Mündungsbereich der Versorgungsleitung in die Druckkammer (2) kleiner ist als in4. Ink printhead according to one of claims 1 to 3, d a d u r c h g e k e n n z e i c h n e t that the cross section of the supply line (3) directly at the mouth of the supply line in the pressure chamber (2) is smaller than in
Strömungsrichtung vor dem Mündungsbereich.Flow direction in front of the mouth area.
5. Tintendruckkopf nach einem der Ansprüche 1 bis 4, d a d u r c h g e k e n n z e i c h n e t , daß der Tintendruckkopf mehrschichtig aufgebaut ist, wobei die Druckkammer (2) und der Düsenkanal (7/1, 8/1) durch konzentrische Ausnehmungen der einzelnen Schichten (1, 7, 8) gebildet wird.5. Ink printhead according to one of claims 1 to 4, characterized in that the ink printhead is constructed in several layers, the pressure chamber (2) and the nozzle channel (7/1, 8/1) through concentric recesses in the individual layers (1, 7, 8 ) is formed.
6. Tintendruckkopf nach einem der Ansprüche 1 bis 5, d a d u r c h g e k e n n z e i c h n e t , daß die Wandlerele mente aus im Querschnitt kreisförmigen Piezoscheiben (5) bestehen. 6. Ink printhead according to one of claims 1 to 5, characterized in that the converter element elements consist of circular piezo discs (5).
PCT/DE1988/000321 1987-06-25 1988-06-01 Ink printing head with tangential-feed pressure chambers WO1988010192A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP3721034.3 1987-06-25
DE3721034 1987-06-25

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WO1988010192A1 true WO1988010192A1 (en) 1988-12-29

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999001284A1 (en) * 1997-07-02 1999-01-14 Xaar Technology Limited Drop on demand ink jet printing apparatus
US6705704B2 (en) 1999-07-30 2004-03-16 Xaar Technology Limited Droplet deposition method and apparatus
EP1629980A3 (en) * 2004-08-31 2006-11-02 Brother Kogyo Kabushiki Kaisha Liquid transport apparatus and method for producing the same
EP1905590A2 (en) * 2006-09-26 2008-04-02 Seiko Epson Corporation Fluid injection device
JP2013059915A (en) * 2011-09-13 2013-04-04 Toshiba Tec Corp Inkjet head

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Publication number Priority date Publication date Assignee Title
EP0252677A2 (en) * 1986-07-11 1988-01-13 Tektronix Inc. Ink jet printing apparatus

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Publication number Priority date Publication date Assignee Title
EP0252677A2 (en) * 1986-07-11 1988-01-13 Tektronix Inc. Ink jet printing apparatus

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Title
IBM Technical Disclosure Bulletin, Band 22, Nr. 2, Juli 1979, (Armonk, NY, US) D.L. Janeway III: "Bubble scrubbing in an ink jet printing head", Seiten 501,502 *
Patent Abstracts of Japan, Band 7, Nr. 145 (M-224)(1290) 24. Juni 1983 & JP-A-5856870 (FUJITSU K.K.) 4. April 1983 *
Patent Abstracts of Japan, Band 7, Nr. 85 (M-206)(1230) 9. April 1983 & JP-A-5811174_(FUJI XEROX K.K.) 21. Januar 1983 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999001284A1 (en) * 1997-07-02 1999-01-14 Xaar Technology Limited Drop on demand ink jet printing apparatus
AU739819B2 (en) * 1997-07-02 2001-10-18 Xaar Technology Limited Drop on demand ink jet printing apparatus
US6422690B1 (en) 1997-07-02 2002-07-23 Xaar Technology Limited Drop on demand ink jet printing apparatus, method of ink jet printing, and method of manufacturing an ink jet printing apparatus
US6705704B2 (en) 1999-07-30 2004-03-16 Xaar Technology Limited Droplet deposition method and apparatus
EP1629980A3 (en) * 2004-08-31 2006-11-02 Brother Kogyo Kabushiki Kaisha Liquid transport apparatus and method for producing the same
US7543919B2 (en) 2004-08-31 2009-06-09 Brother Kogyo Kabushiki Kaisha Liquid transport apparatus and method for producing the same
EP1905590A2 (en) * 2006-09-26 2008-04-02 Seiko Epson Corporation Fluid injection device
EP1905590A3 (en) * 2006-09-26 2013-03-27 Seiko Epson Corporation Fluid injection device
EP2772357A1 (en) * 2006-09-26 2014-09-03 Seiko Epson Corporation Fluid injection device
JP2013059915A (en) * 2011-09-13 2013-04-04 Toshiba Tec Corp Inkjet head

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