EP0019706B1 - Vorrichtung zur Betätigung einer Nadel in einem Nadeldruckwerk - Google Patents

Vorrichtung zur Betätigung einer Nadel in einem Nadeldruckwerk Download PDF

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Publication number
EP0019706B1
EP0019706B1 EP80101919A EP80101919A EP0019706B1 EP 0019706 B1 EP0019706 B1 EP 0019706B1 EP 80101919 A EP80101919 A EP 80101919A EP 80101919 A EP80101919 A EP 80101919A EP 0019706 B1 EP0019706 B1 EP 0019706B1
Authority
EP
European Patent Office
Prior art keywords
magnet
armature
permanent magnet
electro
magnetic
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.)
Expired
Application number
EP80101919A
Other languages
English (en)
French (fr)
Other versions
EP0019706A1 (de
Inventor
Robert Wayne Kulterman
Joseph Edmund Linsinski
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.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
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 International Business Machines Corp filed Critical International Business Machines Corp
Publication of EP0019706A1 publication Critical patent/EP0019706A1/de
Application granted granted Critical
Publication of EP0019706B1 publication Critical patent/EP0019706B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/16—Rectilinearly-movable armatures
    • H01F7/1607—Armatures entering the winding
    • H01F7/1615—Armatures or stationary parts of magnetic circuit having permanent magnet
    • 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
    • B41J2/285—Actuators for print wires of plunger type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
    • H01F7/122—Guiding or setting position of armatures, e.g. retaining armatures in their end position by permanent magnets

Definitions

  • the present invention relates to a print wire control device for a wire matrix printer and more particularly, a type of control device in which no spring contributes to the forward or backward movement of the print wire.
  • Wire matrix printers are well known in the prior art.
  • the printers include a set of thin wires arranged in a vertical column. Each wire can be actuated to be driven forward against a ribbon and a printing medium, such as paper, disposed around the platen of the printer. When the thread is pulled forward and comes into contact with the ribbon, a dot appears on the paper.
  • the control of one or more of the threads during their lateral displacement on the paper can be used to cause the printing of characters, in a manner known in the prior art.
  • One of these wire matrix printers is described in patent FR-A-2253629 filed in France by the applicant on October 16, 1974 and a means of controlling this printer is described in patent FR-A-2374691 France by the plaintiff on October 27, 1977.
  • the devices controlling the movement of the wires forwards consist of an electromagnet to which an electrical signal is applied to create a magnetic field which drives a frame towards the front.
  • the frame is connected to the print wire and when it moves forward, it drives the print wire.
  • Wire control devices using a spring have two drawbacks. The first is that the spring tends to wear out and can therefore be subject to mechanical failure. The second is that the spring applies forces opposing the movement of the wire when the latter is driven forward to strike the ribbon so that, when the wire strikes the ribbon, the force exerted in the opposite direction by the spring is maximum. Thus, a greater supply must be applied to the electromagnet to cause the wire to be driven forward with sufficient force ensuring that a good quality printed point is obtained.
  • US-A-3,946,851 discloses a device in which a permanent magnet controls the return of the printing wire after its movement forward.
  • US-A-3,775,714 discloses a device in which the armature itself is a permanent magnet which controls its own removal after being moved forward. This device has a certain number of drawbacks in that the armature being a permanent magnet, it has low magnetic conduction.
  • US-A-3,755,766 discloses a device in which the permanent magnet is used to hold a frame against a rear stop and in which the electromagnet must be excited with a determined polarity to drive the frame forward and with an opposite polarity to drive it backwards.
  • This control device further comprises a first magnetic circuit comprising the electromagnet and the armature which are traversed by a flux, when the electromagnet is excited, for controlling the forward movement of the printing wire, and a second magnetic circuit comprising the armature and the permanent magnet, which, when the electromagnet is not energized, are traversed by a flux for controlling the backward movement of the printing wire.
  • This device if it offers a clear improvement compared to the previous devices, however presents certain drawbacks in particular relatively large reluctances in the magnetic circuits, which obliges to use a strong supply to control the electromagnet.
  • the action exerted by the permanent magnet is not constant during the displacement of the printing wire.
  • Patent FR-A-2 253 629 describes a wire printer device using a spring, in which the frame, fixed to the printing wire, is held in position by a rear stopper of hard non-magnetic material making it possible to reduce wear of the contact surfaces of the frame and the rear stop. Since the rear stop is located outside the magnetic circuit for controlling the armature, it is chosen from non-magnetic material so as not to disturb the magnetic circuit.
  • the present invention overcomes the above-mentioned drawbacks thanks to a device for printing wire control of the kind comprising two separate magnetic circuits for moving the printing wire respectively forwards and backwards, this device comprising a ring of magnetic material located between the electromagnet and the permanent magnet and defining a magnetic circuit with the electromagnet, the front stop and the armature, this device further comprising a rear stop, on which rests the armature fixed to the printing wire, which is made of a non-metallic material magnetic.
  • the present invention also relates to a device for controlling printing threads in which the magnetic forces used for controlling the movement of the thread are relatively low.
  • FIGS 1 and 2 show a device of the prior art as described in the review "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, June 1978.
  • the printing control device comprises an armature 10 fixed to the printing wire 12.
  • the armature is held in its initial or rest position, against the rear stop 14, by the permanent magnet 16.
  • the rear stop consists of a magnetic material with low reluctance, such as soft iron.
  • the frame 10 moves inside a plastic casing 20, this casing containing the permanent magnet 16 and an electromagnet 18.
  • a front stop 24, made of magnetic material, is in contact with a magnetic housing 22 for define a trajectory with low reluctance.
  • a space 26 is provided between the frame 10 and the stop 24, and its length is equal to the desired displacement of the wire 12.
  • the magnetic circuit in which the flux created by the electromagnet 18 flows, comprises the magnetic box 22, the front stop 24 and the frame 10. Due to the structure of the non-magnetic casing 20, the magnetic force produced by the electromagnet 18 must be relatively large to overcome that produced by the permanent magnet 16, which is a disadvantage for the control device.
  • FIGS. 3 and 4 describe the ideal action of a permanent magnet 40 in the form of a hollow cylinder on a magnetic bar placed in the center of the permanent magnet 40.
  • the magnetic force applied by the permanent magnet 40 to the bar 42 is such that the bar 42 arrives in an equilibrium position when its medium is in the center of the magnet 40. This is due to the fact that the magnetic path having the lowest reluctance is obtained when the bar 42 is centrally disposed in the magnet 40.
  • Figure 4 is a graphic representation of the magnetic force exerted on the bar 42 by the magnet 40 when the bar 42 is moved over a distance d.
  • a positive force (+ F) is defined on the right, a negative force (-F) on the left; a positive movement (+ d) is defined as the movement of the bar 42 to the right and a negative movement (-d) is defined as the movement of the bar 42 to the left.
  • the position of the bar 42 shown in Figure 3 is the equilibrium position.
  • the induced magnetic force increases on the bar 42 until a maximum force is reached.
  • the forces applied to the bar 42 remain relatively constant, which is shown by the flat part 44 of the curve in FIG. 4. After the bar 42 has been sufficiently distant from the magnet 40, the forces applied to it rapidly decrease and become zero.
  • the permanent magnet assembly 40 - bar 42 can be compared to the permanent magnet assembly 16 - armature 10. It is desirable that the forces exerted on the armature 10 correspond to the flat part 44 of FIG. 4. Given the low possible displacement of the armature 10 relative to the length of the magnet 16, it could be considered that the forces applied to this armature actually correspond to the flat part 44. However, due to the structure of the control device in FIG. 1, the representation of the magnetic force exerted by the magnet 16 does not correspond to that of FIG. 4. In fact, the permeability of the stop 14 is much greater than that of the casing 20, which causes an imbalance in the diagram of the forces exerted on the armature and a non-linearity of the action of the forces during the displacement of the bar.
  • the present invention overcomes the drawbacks presented by the device of Figure 1.
  • the control device of Figure 5 comprises a frame 50 connected to the printing wire 52 which is in position rest against the rear stop 54.
  • the rear stop 54 in the embodiment of Figure 5 is made of a very hard non-magnetic metallic material. It has been found that cobalt sold under the brand name "Stellite” by Haynes Stellite Incorporated is a suitable material.
  • the rear stop 54 could be made of hardened beryllium copper.
  • the rear stop 54 being made of non-magnetic material, the diagram of the forces exerted by the permanent magnet 56 is very close to the theoretical diagram of FIG.
  • the material making up the rear stop must be made of a very hard material because of the very high number of times it is struck by the armature 10 (several billion times ) after de-energizing the electromagnet 58.
  • the control device of FIG. 5 also includes the electromagnet 58 and the plastic casing 60 containing the permanent magnet 56 and the electromagnet 58.
  • the permanent magnet 56 is a hollow cylinder made, for example, by an alloy cobalt-samarium and is arranged so that the north pole is opposite the stop 54.
  • the electromagnet 58 is also in the form of a hollow cylinder having the same internal diameter as the permanent magnet 56 and disposed adjacent to this permanent magnet.
  • control device of Figure 5 comprises a housing of magnetic material 62 and the front stop 64 both made of a magnetic material such as soft iron.
  • the front stop 64 is arranged so as to form a gap 66 between the frame 50 and the front stop 64 of a length equal to the length of the desired movement of the wire 52.
  • the structure of the casing 20 made it necessary to supply a strong supply to the electromagnet 18 because the path of the magnetic flux exhibited a significant reluctance. This was mainly due to the large non-magnetic gap between the left end of the electromagnet and the armature 50, as well as to the magnetic insulation separating the electromagnet from the magnet 16.
  • a crown 76 is disposed between the magnet 56 and the electromagnet 58, this crown being in contact with the housing.
  • This crown 76 is also constituted by a magnetic material such as soft iron.
  • the purpose of the ring 76 is to ensure a better magnetic circuit trajectory for the electromagnet 58 so that the flux flows with less reluctance, through the housing 62 and the ring 76, in the frame 50. This allows the application of less power to the conductors 68 and 70 connected to the electromagnet 58.
  • the control device of FIG. 5 also includes a plating of non-magnetic material such as chromium on the end 72 of the front stop 64. This thin plating makes it possible to eliminate any residual effect of the flow of the flux from the magnet permanent 56 through the housing 62 and the front stop 64, an effect which tended to attract the armature 50 towards the front stop 64 after the electromagnet 58 had de-energized.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Impact Printers (AREA)
  • Electromagnets (AREA)
  • Coating With Molten Metal (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)

Claims (6)

1. Vorrichtung zur Steuerung der AnschlagElemente von Drahtdruckern mit einem Elektromagneten (58) und einem Permanentmagneten (56), jeweils in der Form eines Hohlzylinders, mit einer am Druckdraht befestigten sich im Innern des Elektromagneten und des Permanentmagneten befindlichen Anker (50), welcher sich zwischen einem hinteren (54) und einem vorderen Anschlag (64) bewegen kann, wobei der Magnetfluß in einem ersten magnetischen Kreis, bestehend aus dem erregenden Elektromagneten, dem Anker und dem hinteren Anschlag, die Vorwärtsbewegung des Druckdrahtes steuert, und wobei der Magnetfluß in einem zweiten magnetischen Kreis, bestehend aus dem Permanentmagneten und dem Anker, die Rückwärtsbewegung des Druckerdrahtes steuert, wenn der Elektromagnet nicht erregt ist, dadurch gekennzeichnet, daß ein hohles, zylinderförmiges Element (76) zwischen dem Elektromagneten und dem Permanentmagneten vorgesehen ist, um mit dem Elektromagneten, dem vorderen Anschlag und dem Anker einen magnetischen Kreis zu bilden, und daß der hintere Anschlag aus nicht magnetisierbarem Material besteht.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der erste magnetische Kreis zusätzlich ein Gehäuse (62) aus magnetisierbarem Material umfaßt und daß der erste magnetische Kreis von dem Elektromagneten, dem Gehäuse, dem Anker und dem hohlen zylinderförmigen Element gebildet wird.
3. Vorrichtung nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß sich das vordere Ende des hinteren Anschlages etwa im Zentrum des Permanentmagneten befindet.
4. Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß zusätzlich eine Plastikhülse (60) aus nicht-magnetisierbarem Material vorgesehen ist, auf der der Elektromagnet und der Permanentmagnet angeordnet sind.
5. Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß der hintere Anschlag aus metallischem Material besteht, welches aus der Kobalt und Berylliumkupfer enthaltenden Gruppe ausgewählt ist.
6. Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß das hintere Ende des vorderen Anschlages mit einer Schicht (72) aus nicht-magnetisierbarem Material überzogen ist.
EP80101919A 1979-05-29 1980-04-10 Vorrichtung zur Betätigung einer Nadel in einem Nadeldruckwerk Expired EP0019706B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4318379A 1979-05-29 1979-05-29
US43183 1979-05-29

Publications (2)

Publication Number Publication Date
EP0019706A1 EP0019706A1 (de) 1980-12-10
EP0019706B1 true EP0019706B1 (de) 1983-09-21

Family

ID=21925911

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80101919A Expired EP0019706B1 (de) 1979-05-29 1980-04-10 Vorrichtung zur Betätigung einer Nadel in einem Nadeldruckwerk

Country Status (8)

Country Link
EP (1) EP0019706B1 (de)
JP (1) JPS55161673A (de)
AU (1) AU529042B2 (de)
BR (1) BR8003344A (de)
CA (1) CA1136198A (de)
DE (1) DE3064880D1 (de)
ES (1) ES491905A0 (de)
IT (1) IT1151029B (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03126970A (ja) * 1989-10-12 1991-05-30 Masanobu Nakamura 複写機用ロールおよびその製造方法
US5793392A (en) * 1995-06-13 1998-08-11 Tschida; Mark J. Printing apparatus and method

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2126491A5 (de) * 1971-02-08 1972-10-06 Burroughs Corp
FR2228619B3 (de) * 1973-05-10 1977-03-11 Lrc Inc
DE2614004A1 (de) * 1975-04-16 1976-10-28 Bridon Engineering Ltd Betaetigungsvorrichtung
JPS5239414A (en) * 1975-09-25 1977-03-26 Oki Electric Ind Co Ltd Type solenoid

Also Published As

Publication number Publication date
IT8020721A0 (it) 1980-03-18
ES8103411A1 (es) 1981-02-16
DE3064880D1 (en) 1983-10-27
IT8020721A1 (it) 1982-06-18
AU529042B2 (en) 1983-05-26
BR8003344A (pt) 1980-12-30
EP0019706A1 (de) 1980-12-10
JPS6122638B2 (de) 1986-06-02
JPS55161673A (en) 1980-12-16
IT1151029B (it) 1986-12-17
ES491905A0 (es) 1981-02-16
AU5813980A (en) 1980-12-04
CA1136198A (en) 1982-11-23

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