EP0384095A1 - Matrix needle printhead of the pre-tensed type - Google Patents

Matrix needle printhead of the pre-tensed type Download PDF

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Publication number
EP0384095A1
EP0384095A1 EP89730039A EP89730039A EP0384095A1 EP 0384095 A1 EP0384095 A1 EP 0384095A1 EP 89730039 A EP89730039 A EP 89730039A EP 89730039 A EP89730039 A EP 89730039A EP 0384095 A1 EP0384095 A1 EP 0384095A1
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EP
European Patent Office
Prior art keywords
permanent magnet
electromagnetic coil
soft magnetic
magnetic flux
matrix needle
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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.)
Granted
Application number
EP89730039A
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German (de)
French (fr)
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EP0384095B1 (en
Inventor
Bernd Gugel
Matthias Ullrich
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Vodafone GmbH
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Mannesmann AG
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Filing date
Publication date
Application filed by Mannesmann AG filed Critical Mannesmann AG
Priority to AT89730039T priority Critical patent/ATE93773T1/en
Priority to EP89730039A priority patent/EP0384095B1/en
Priority to DE89730039T priority patent/DE58905472D1/en
Priority to JP2031290A priority patent/JPH02292051A/en
Priority to US07/481,166 priority patent/US5073051A/en
Publication of EP0384095A1 publication Critical patent/EP0384095A1/en
Application granted granted Critical
Publication of EP0384095B1 publication Critical patent/EP0384095B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/22—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material
    • B41J2/23—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material using print wires
    • B41J2/27—Actuators for print wires
    • B41J2/28—Actuators for print wires of spring charge type, i.e. with mechanical power under electro-magnetic control

Definitions

  • Such a matrix needle printhead which is generally equipped with a permanent magnet in a manner differing from the hinged armature type, brings about a first main magnetic flux circuit via the core of the electromagnetic coil, the armature body or armature, the spacer ring, the permanent magnet, the base plate and back.
  • This optimization of the holding force of the permanent magnet can now be set according to the known proposal by a magnetic property of the shunt ring such that the magnetic resistance of the adjusting yoke increases with increasing temperature of the adjusting yoke (shunt ring).
  • each electromagnetic coil is partially or completely surrounded by soft magnetic materials on its circumference and is thus shielded from the magnetic field of adjacent electromagnetic coils.
  • the soft magnetic materials act as resistors for neighboring electromagnetic fields, so that the previous field weakening can be eliminated as far as possible and thus the reduction in performance no longer occurs or an increase in performance by the aforementioned 30% can be achieved.
  • a partition made of soft magnetic material is arranged between every two solenoid coils.
  • Such a partition can e.g. can be easily manufactured together with the base plate as a one-piece sintered piece.
  • Another possibility to rule out the mutual influence of the magnetic fields is formed by the additionally applicable improvement that diametrically opposed electromagnetic coils are shielded from one another by means of a core ring or by means of core ring segments which are concentric or in elliptical shape to the printhead center axis.
  • a matrix needle pressure head of the pretensioned type has a base plate 1 made of soft magnetic material, furthermore an annular permanent magnet 2, a spacer ring 3, also made of soft magnetic material, also a spring 4 clamped radially on the outside for each pressure element 4a, a mounting plate 5, one on the spring 4 attached armature body 6, which can be tightened against a core 7 of an electromagnetic coil 8 with the help of the permanent magnet 2.
  • the main magnetic flux circuit 9 is canceled.
  • the energization of the electromagnetic coil 8 thus abolishes the force of the permanent magnet 2 and the bias energy stored in the spring 4 becomes free for the firing of the pressure element 4a.
  • An air gap 10 is temporarily created between the core 7 and the armature body 6.
  • a shunt magnetic circuit is not drawn because it is not required for understanding the invention.
  • Another measure for shielding external magnetic fields form a core ring or core ring segments 15, which are arranged concentrically to the printhead center axis 16 (see FIGS. 7 and 8).

Abstract

A matrix needle print head, in particular of the pretensioned design, has a baseplate (1) of low-retentivity material, an annular permanent magnet (2), a spacing ring (3), a spring (4) which is radially outwardly clamped in each case and to which an armature body (6) is attached and can be pretensioned in each case against the core (7) of an electromagnetic coil (8) arranged in each case on the baseplate (1), it being possible to eliminate the magnetic flux generated by the permanent magnet (2) by supplying the electromagnetic coil (8) with current and it being possible to push the armature body (6), to which a printing element (4a) is attached, against a recording carrier and, if appropriate, a secondary magnetic flux circuit being formed to the main magnetic flux circuit (9) formed via the permanent magnet (2) via a short-circuit body. <??>In order to avoid a power-reducing influencing of adjacent electromagnetic coils by their magnetic fields, it is proposed according to the invention to surround each electromagnetic coil (8) on its circumference (8a) partially or completely with low-retentivity materials (11). <IMAGE>

Description

Die Erfindung betrifft einen Matrixnadeldruckkopf der vorgespannten Bauart mit einer Grundplatte aus weichmagnetischem Werkstoff, einem darauf angeordneten ringförmigen Dauermagneten, einem Distanzring aus weichmagnetischem Werkstoff, einer jeweils radial außen eingespannten Feder, an der radial innen jeweils ein Ankerkörper befestigt ist, der jeweils gegen den Kern einer jeweils auf der Grundplatte angeordneten Elektromagnetspule vorspannbar ist, wobei der durch den Dauermagneten erzeugte Magnetfluß durch Bestromen der Elektromagnetspule aufhebbar bzw. verdrängbar und der Ankerkörper, an dem ein Druckelement befestigt ist, gegen einen Aufzeichnungsträger abschießbar ist und wobei zudem über den Dauermagneten gebildeten Hauptmagnerflußkreis ggf. ein Nebenmagnetflußkreis über einen Kurzschlußkörper gebildet ist.The invention relates to a matrix needle printhead of the pretensioned type with a base plate made of soft magnetic material, an annular permanent magnet arranged thereon, a spacer ring made of soft magnetic material, a spring clamped radially on the outside, to each of which an armature body is fastened radially on the inside, each against the core of one each arranged on the base plate is biased, the magnetic flux generated by the permanent magnet can be canceled or displaced by energizing the electromagnetic coil and the armature body, to which a pressure element is attached, can be fired against a recording medium and, moreover, the main magnetic flux circuit formed by the permanent magnet may be a secondary magnetic flux circuit is formed via a short-circuit body.

Ein derartiger Matrixnadeldruckkopf, der im allgemeinen abweichend von der Klappankerbauart mit einem Dauermagneten ausgerüstet ist, bewirkt über den Kern der Elektromagnetspule, über den Ankerkörper bzw. Anker, den Distanzring, den Dauermagneten, die Grundplatte und zurück einen ersten Hauptmagnetflußkreis.Such a matrix needle printhead, which is generally equipped with a permanent magnet in a manner differing from the hinged armature type, brings about a first main magnetic flux circuit via the core of the electromagnetic coil, the armature body or armature, the spacer ring, the permanent magnet, the base plate and back.

Es ist schon vorgeschlagen worden (DE 31 10 798), zur Optimierung des Hauptmagnetflußkreises einen parallelen Widerstand, der aus einem Kurzschlußkörper gebildet wird, als einen Nebenmagnetflußkreis zu schaffen, der den Hauptmagnetflußkreis auf eine Intensität reduziert, so daß eine geringe Bestromung (Ampere-Windungszahl) der Elektromagnetspule ausreicht, um das Magnetfeld des Dauermagneten vollends aufzuheben, d.h. den an der Feder befestigten Ankerkörper, an dem sich ein Druckelement befindet, abzuschießen, so daß das Druckelement auf dem Papier einen Punkt erzeugt.It has already been proposed (DE 31 10 798), to optimize the main magnetic flux circuit, to create a parallel resistor, which is formed from a short-circuit body, as a secondary magnetic flux circuit, which reduces the main magnetic flux circuit to an intensity, so that a low current (ampere number of turns ) the electromagnetic coil is sufficient to completely cancel the magnetic field of the permanent magnet, ie to shoot off the armature body attached to the spring, on which there is a pressure element, so that the pressure element creates a dot on the paper.

Diese sogenannte Optimierung der Feldlinienführung läßt das Produkt aus Stromstärke mal Windungszahl sinken, so daß entweder mit geringerer Stromstärke oder mit geringerer Windungszahl des Kupferdrahtes oder mit etwas weniger verringerter Stromstärke und weniger verringerter Windungszahl konstruiert werden kann. Hierbei schlägt eine verringerte Stromstärke durch reduzierte Verlustwärme zu Buche.This so-called optimization of the field line routing allows the product of current strength times the number of turns to decrease, so that construction can be carried out either with a lower current strength or with a lower number of turns of the copper wire or with somewhat less reduced current strength and less reduced number of turns. In this case, a reduced current intensity due to reduced heat loss has an impact.

Diese Optimierung der Haltekraft des Dauermagneten kann nunmehr nach dem bekannten Vorschlag durch eine magnetische Eigenschaft des Nebenschlußringes derart eingestellt werden, daß der magnetische Widerstand des Einstelljoches mit steigender Temperatur des Einstelljoches (Nebenschlußringes) zunimmt.This optimization of the holding force of the permanent magnet can now be set according to the known proposal by a magnetic property of the shunt ring such that the magnetic resistance of the adjusting yoke increases with increasing temperature of the adjusting yoke (shunt ring).

Ein anderer bekannter Vorschlag (DE-Patent 36 44 185), der sich ebenfalls mit der Optimierung der Haltekraft beschäftigt, löst das Optimierungsproblem dadurch, daß die Dicke des Nebenschlußringes in Abhängigkeit des Hauptschlußmagnetkreises mit dem Dauermagneten variabel ist und zur Abstimmung auf den Arbeitspunkt ein Nebenschlußring mit der entsprechenden Dicke eingesetzt ist.Another known proposal (DE-Patent 36 44 185), which also deals with the optimization of the holding force, solves the optimization problem in that the thickness of the shunt ring is variable depending on the main shunt magnetic circuit with the permanent magnet and a shunt ring to match the working point is used with the appropriate thickness.

Aufgrund langjähringer Erfahrungen in der Praxis und aufgrund von Versuchen wurde jedoch festgestellt, daß die Leistungsfähigkeit eines vorgespannten Systems Dauermagnet/Elektromagnet nicht nur von der Optimierung der Haltekraft des Dauermagneten abhängig ist, sondern daß die gleichzeitige Bestromung zweier benachbarter oder mehrerer Elektromagnetspulen wegen des gleichzeitigen Abdruckens zweier Druckpunkte in einem Schriftzeichen, wie z.B. in einem Buchstaben "E", "F" und anderen, zu einer gegenseitigen Durchflutung mehrerer Elektromagnetfelder führt, bei der benachbarte Magnetfelder gegensinnig wirken und zu einer wesentlich schlechteren Aufhebung bzw. Verdrängung des Magnetfeldes führen. Es wurde gemessen, daß die Druckschnelligkeit durch diese gegenseitige Beeinflussung der Magnetfelder um ca. 30 % absinkt.Based on many years of experience in practice and tests, it was found that the performance of a pre-stressed permanent magnet / electromagnet system not only depends on the optimization of the holding force of the permanent magnet, but that the simultaneous energization of two adjacent or more electromagnetic coils due to the simultaneous printing of two Pressure points in a character, such as in a letter "E", "F" and others, lead to a mutual flooding of several electromagnetic fields, in which neighboring magnetic fields act in opposite directions and to a much poorer cancellation or displacement of the magnetic field. It was measured that the pressure speed drops by about 30% due to this mutual influence of the magnetic fields.

Der vorliegenden Erfindung liegt daher nicht die Aufgabe der beiden bekannten Lösungen zugrunde, d.h. die Haltekraft-Optimierung, sondern die neue Aufgabe, die leistungsmindernde Beeinflussung zweier benachbarter Elektromagnetspulen des Dauermagnet/Elektromagnet-Systems zu vermeiden.The present invention is therefore not based on the object of the two known solutions, i.e. the holding force optimization, but the new task of avoiding the performance-reducing influence of two adjacent electromagnetic coils of the permanent magnet / electromagnet system.

Die gestellte Aufgabe wird erfindungsgemäß dadurch gelöst, daß jede Elektromagnetspule an ihrem Umfang teilweise oder ganz mittels weichmagnetischen Werkstoffen umgeben und dadurch gegen das Magnetfeld benachbarter Elektromagnetspulen abgeschirmt ist. Die weichmagnetischen Werkstoffe wirken für benachbarte Elektromagnetfelder als Widerstände, so daß die bisherige Feldschwächung weitestgehend beseitigt werden kann und somit die Leistungsverminderung nicht mehr auftritt bzw. eine Leistungssteigerung um die erwähnten 30 % erreicht werden kann.The object is achieved in that each electromagnetic coil is partially or completely surrounded by soft magnetic materials on its circumference and is thus shielded from the magnetic field of adjacent electromagnetic coils. The soft magnetic materials act as resistors for neighboring electromagnetic fields, so that the previous field weakening can be eliminated as far as possible and thus the reduction in performance no longer occurs or an increase in performance by the aforementioned 30% can be achieved.

Die praktische Anwendbarkeit des Erfindungsgrundgedankens wird dadurch gesteigert, daß bei teilweiser Abschirmung einer Elektromagnetspule zwischen jeweils zwei Elektromagnetspulen eine Trennwand aus weichmagnetischem Werkstoff angeordnet ist. Eine solche Trennwand kann z.B. leicht zusammen mit der Grundplatte hergestellt werden als einteiliges Sinterstück.The practical applicability of the basic idea of the invention is increased by the fact that when a solenoid coil is partially shielded, a partition made of soft magnetic material is arranged between every two solenoid coils. Such a partition can e.g. can be easily manufactured together with the base plate as a one-piece sintered piece.

Eine vollständige Abschirmung wird dadurch erzielt, daß von benachbarten Elektromagnetspulen zumindest eine mittels eines Ringes aus weichmagnetischem Werkstoff umgeben ist.Complete shielding is achieved in that at least one is surrounded by adjacent electromagnetic coils by means of a ring made of soft magnetic material.

Eine andere Lösungsmöglichkeit ergibt sich daraus, daß sämtliche Elektromagnetspulen mittels einer fließfähigen Masse aus magnetisch nicht Leitendem Werkstoff, in die weichmagnetische Partikel eingemischt sind, umgossen ist. Diese nur bei Einbringen fließfähige Masse erhärtet zunehmend und wirkt wie eine vollständige Umhüllung mittels der erwähnten Ringe.Another possible solution results from the fact that all the electromagnetic coils are encapsulated by means of a flowable mass of magnetically non-conductive material, into which soft magnetic particles are mixed. This mass, which is flowable only when it is introduced, increasingly hardens and acts as a complete covering by means of the rings mentioned.

Eine andere Möglichkeit, die gegenseitige Beeinflussung der Magnetfelder auszuschließen, wird durch die zusätzlich anwendbare Verbesserung gebildet, daß sich diametral gegenüberliegende Elektromagnetspulen mittels eines Kernrings oder mittels Kernringsegmenten, die konzentrisch oder in Ellipsen-Form zur Druckkopfmittelachse liegen, gegeneinander abgeschirmt sind.Another possibility to rule out the mutual influence of the magnetic fields is formed by the additionally applicable improvement that diametrically opposed electromagnetic coils are shielded from one another by means of a core ring or by means of core ring segments which are concentric or in elliptical shape to the printhead center axis.

Ausführungsbeispiele der Erfindung sind in der Zeichnung schematisch dargestellt und werden nachfolgend näher beschrieben. Es zeigen:

  • Fig. 1 einen halbseitigen Querschnitt durch den Matrixnadeldrukkopf der vorgespannten Bauart,
  • Fig. 2 eine Draufsicht zu Fig. 1, um 90 Grad gedreht, bei abgenommenem Anker,
  • Fig. 3 den halbseitigen Querschnitt gemäß Fig. 1 für ein zweites Ausführungsbeispiel,
  • Fig. 4 eine Draufsicht zu Fig. 3 bei abgenommenem Anker,
  • Fig. 5 den halbseitigen Querschnitt gemäß Fig. 1 für ein zweites Ausführungsbeispiel,
  • Fig. 6 die Draufsicht zu Fig. 5 bei abgenommenem Anker,
  • Fig. 7 den halbseitigen Querschnitt gemäß Fig. 1 für ein drittes Ausführungsbeispiel und
  • Fig. 8 eine Draufsicht auf Fig. 7 bei abgenommenem Anker.
Embodiments of the invention are shown schematically in the drawing and are described in more detail below. Show it:
  • 1 is a half-sided cross section through the matrix needle pressure head of the biased type,
  • 2 is a plan view of FIG. 1, rotated 90 degrees, with the anchor removed,
  • 3 shows the half-sided cross section according to FIG. 1 for a second exemplary embodiment,
  • 4 is a plan view of FIG. 3 with the anchor removed,
  • 5 shows the half-sided cross section according to FIG. 1 for a second exemplary embodiment,
  • 6 shows the top view of FIG. 5 with the anchor removed,
  • Fig. 7 shows the half-sided cross section of FIG. 1 for a third embodiment and
  • Fig. 8 is a plan view of Fig. 7 with the anchor removed.

Ein Matrixnadeldrukkopf der vorgespannten Bauart weist eine Grundplatte 1 aus weichmagnetischem Werkstoff auf, ferner einen ringförmigen Dauermagneten 2, einen Distanzring 3, ebenfalls aus weichmagnetischem Werkstoff, außerdem eine jeweils radial außen eingespannte Feder 4 für jedes Druckelement 4a, eine Befestigungsplatte 5, einen an der Feder 4 befestigter Ankerkörper 6, der jeweils gegen einen Kern 7 einer Elektromagnetspule 8 anziehbar ist mit Hilfe des Dauermagneten 2. Bei Bestromen einer Elektromagnetspule 8 wird der Hauptmagnetflußkreis 9 aufgehoben. Die Bestromung der Elektromagnetspule 8 hebt somit die Kraft des Dauermagneten 2 auf und die in der Feder 4 gespeicherte Vorspannungsenergie wird frei für das Abschießen des Druckelementes 4a. Hierbei entsteht zwischen dem Kern 7 und dem Ankerkörper 6 vorübergehend ein Luftspalt 10.A matrix needle pressure head of the pretensioned type has a base plate 1 made of soft magnetic material, furthermore an annular permanent magnet 2, a spacer ring 3, also made of soft magnetic material, also a spring 4 clamped radially on the outside for each pressure element 4a, a mounting plate 5, one on the spring 4 attached armature body 6, which can be tightened against a core 7 of an electromagnetic coil 8 with the help of the permanent magnet 2. When energizing an electromagnetic coil 8, the main magnetic flux circuit 9 is canceled. The energization of the electromagnetic coil 8 thus abolishes the force of the permanent magnet 2 and the bias energy stored in the spring 4 becomes free for the firing of the pressure element 4a. An air gap 10 is temporarily created between the core 7 and the armature body 6.

Ein Nebenschlußmagnetkreis ist nicht gezeichnet, weil ein solcher für das Verständnis der Erfindung nicht benötigt wird.A shunt magnetic circuit is not drawn because it is not required for understanding the invention.

Die Abschirmung der Elektromagnetspulen 8 untereinander erfolgt nach einem ersten Ausführungsbeispiel (Fig. 1 und 2) dadurch, daß jede Elektromagnetspule 8 an ihrem Umfang 8a mittels weichmagnetischer Werkstoffe (z.B. Weicheisen, Stahl mit geringem Kohlenstoff-Gehalt) 11 umgeben ist, was wie gezeichnet durch beidseitig angeordnete Trennwände 12 z.B. aus Weicheisen erfolgen kann.The shielding of the electromagnetic coils 8 from one another is carried out according to a first embodiment (FIGS. 1 and 2) in that each electromagnetic coil 8 is surrounded on its circumference 8a by means of soft magnetic materials (for example soft iron, steel with a low carbon content) 11, as shown by Partitions 12 arranged on both sides can be made of soft iron, for example.

Gemäß einem zweiten Ausführungsbeispiel (Fig. 3 und 4) wird eine Elektromagnetspule 8 mittels eines Ringes 13 aus weichmagnetischem Werkstoff umgeben.According to a second exemplary embodiment (FIGS. 3 and 4), an electromagnetic coil 8 is surrounded by a ring 13 made of soft magnetic material.

Ein drittes Ausführungsbeispiel (Fig. 5 und 6) zeigt, daß sämtliche Elektromagnetspulen 8 mit einer fließfähigen Masse 14 aus magnetisch nicht leitendem Werkstoff umgossen sind, wobei in diese Masse 14 z.B. Weicheisenpulver bzw. ferromagnetische pulverisierte Werkstoffe eingemischt und verteilt sind.A third exemplary embodiment (FIGS. 5 and 6) shows that all of the electromagnetic coils 8 are encapsulated with a flowable mass 14 made of magnetically non-conductive material, with mass 14 e.g. Soft iron powder or ferromagnetic powdered materials are mixed in and distributed.

Eine andere Maßnahme zur Abschirmung von fremdeinwirkenden Magnetfeldern (Elektromagnetfelder und Dauermagnetfelder) bilden einen Kernring oder Kernringsegmente 15, die konzentrisch zur Druckkopfmittelachse 16 angeordnet sind (s. Fig. 7 und 8).Another measure for shielding external magnetic fields (electromagnetic fields and permanent magnetic fields) form a core ring or core ring segments 15, which are arranged concentrically to the printhead center axis 16 (see FIGS. 7 and 8).

Claims (5)

1. Matrixnadeldruckkopf, insbesondere der vorgespannten Bauart, mit einer Grundplatte aus weichmagnetischem Werkstoff, einem darauf angeordneten ringförmigen Dauermagneten, einem Distanzring aus weichmagnetischem Werkstoff, einer jeweils radial außen eingespannten Feder, an der radial innen jeweils ein Ankerkörper befestigt ist, der jeweils gegen den Kern einer jeweils auf der Grundplatte angeordneten Elektromagnetspule vorspannbar ist, wobei der durch den Dauermagneten erzeugte Magnetfluß durch Bestromen der Elektromagnetspule aufhebbar und der Ankerkörper, an dem ein Druckelement befestigt ist, gegen einen Aufzeichnungsträger abschießbar ist und wobei zu dem über den Dauermagneten gebildeten Hauptmagnetflußkreis ggf. ein Nebenmagnetflußkreis über einen Kurzschlußkörper gebildet ist,
dadurch gekennzeichnet,
daß jede Elektromagnetspule (8) an ihrem Umfang (8a) teilweise oder ganz mit weichmagnetischen Werkstoffen (11) umgeben und dadurch gegen das Magnetfeld benachbarter Elektromagnetspulen (8) abgeschirmt ist.1.Matrix needle printhead, in particular of the pretensioned type, with a base plate made of soft magnetic material, an annular permanent magnet arranged thereon, a spacer ring made of soft magnetic material, a spring clamped radially on the outside, to each of which an anchor body is fastened radially on the inside, each against the core an electromagnetic coil arranged on the base plate in each case can be pretensioned, the magnetic flux generated by the permanent magnet being able to be canceled by energizing the electromagnetic coil and the armature body, to which a pressure element is fastened, being able to be fired against a recording medium and, if appropriate, to the main magnetic flux circuit formed by the permanent magnet Secondary magnetic flux circuit is formed via a short-circuit body,
characterized,
that each electromagnetic coil (8) is partially or completely surrounded on its circumference (8a) with soft magnetic materials (11) and is thus shielded from the magnetic field of adjacent electromagnetic coils (8). 2. Matrixnadeldruckkopf nach Anspruch 1,
dadurch gekennzeichnet,
daß bei teilweiser Abschirmung einer Elektromagnetspule (8) zwischen jeweils zwei Elektromagnetspulen (8) eine Trennwand (12) aus weichmagnetischem Werkstoff (11) angeordnet ist.2. matrix needle printhead according to claim 1,
characterized,
that with partial shielding of an electromagnetic coil (8) between each two electromagnetic coils (8) a partition (12) made of soft magnetic material (11) is arranged. 3. Matrixnadeldruckkopf nach Anspruch 1,
dadurch gekennzeichnet,
daß von benachbarten Elektromagnetspulen (8) zumindest eine von einem Ring (13) aus weichmagnetischem Werkstoff (11) umgeben ist.3. matrix needle printhead according to claim 1,
characterized,
that at least one of adjacent electromagnetic coils (8) is surrounded by a ring (13) made of soft magnetic material (11). 4. Matrixnadeldruckkopf nach Anspruch 1,
dadurch gekennzeichnet,
daß sämtliche Elektromagnetspulen (8) mit einer fließfähigen Masse (14) aus magnetisch nicht leitendem Werkstoff, in die weichmagnetische Partikel eingemischt sind, umgossen sind.4. matrix needle printhead according to claim 1,
characterized,
that all electromagnetic coils (8) are encapsulated with a flowable mass (14) made of magnetically non-conductive material into which soft magnetic particles are mixed. 5. Matrixnadeldruckkopf nach Anspruch 1,
dadurch gekennzeichnet,
daß sich diametral gegenüberliegende Elektromagnetspulen (8) mittels eines Kernrings oder mittels Kernringsegmenten (15), die konzentrisch oder in Ellipsen-Form zur Druckkopfmittelachse (16) liegen, gegeneinander abgeschirmt sind.5. matrix needle printhead according to claim 1,
characterized,
that diametrically opposed electromagnetic coils (8) are shielded from one another by means of a core ring or by means of core ring segments (15) which are concentric or in the form of an ellipse to the center of the print head (16).
EP89730039A 1989-02-20 1989-02-20 Matrix needle printhead of the pre-tensed type Expired - Lifetime EP0384095B1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
AT89730039T ATE93773T1 (en) 1989-02-20 1989-02-20 LOADING TYPE DOCUMENT MATRIX PRINT HEAD.
EP89730039A EP0384095B1 (en) 1989-02-20 1989-02-20 Matrix needle printhead of the pre-tensed type
DE89730039T DE58905472D1 (en) 1989-02-20 1989-02-20 Matrix printhead of the preloaded type.
JP2031290A JPH02292051A (en) 1989-02-20 1990-02-09 Dot matrix printing head
US07/481,166 US5073051A (en) 1989-02-20 1990-02-20 Matrix pin print head having a shield to counter magnetic fields

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP89730039A EP0384095B1 (en) 1989-02-20 1989-02-20 Matrix needle printhead of the pre-tensed type

Publications (2)

Publication Number Publication Date
EP0384095A1 true EP0384095A1 (en) 1990-08-29
EP0384095B1 EP0384095B1 (en) 1993-09-01

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Application Number Title Priority Date Filing Date
EP89730039A Expired - Lifetime EP0384095B1 (en) 1989-02-20 1989-02-20 Matrix needle printhead of the pre-tensed type

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US (1) US5073051A (en)
EP (1) EP0384095B1 (en)
JP (1) JPH02292051A (en)
AT (1) ATE93773T1 (en)
DE (1) DE58905472D1 (en)

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Publication number Priority date Publication date Assignee Title
US5310271A (en) * 1991-04-30 1994-05-10 Oki Electric Industry Co., Ltd. Solenoid actuator
GB9114512D0 (en) * 1991-07-04 1991-08-21 Cyzer John A Improved label printing apparatus
US6710593B2 (en) * 2001-07-25 2004-03-23 American Electronic Components, Inc. Rotary position sensor with a self-lubricating bearing

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US4258623A (en) * 1979-01-30 1981-03-31 Printronix, Inc. Print hammer mechanism having dual electromagnetic coils and pole pieces
US4527469A (en) * 1983-04-15 1985-07-09 Dataproducts Corporation Dot matrix print actuator

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ATE93773T1 (en) 1993-09-15
DE58905472D1 (en) 1993-10-07
JPH02292051A (en) 1990-12-03
EP0384095B1 (en) 1993-09-01
US5073051A (en) 1991-12-17

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