EP0228589A2 - Nadeldruckkopf - Google Patents

Nadeldruckkopf Download PDF

Info

Publication number
EP0228589A2
EP0228589A2 EP86116768A EP86116768A EP0228589A2 EP 0228589 A2 EP0228589 A2 EP 0228589A2 EP 86116768 A EP86116768 A EP 86116768A EP 86116768 A EP86116768 A EP 86116768A EP 0228589 A2 EP0228589 A2 EP 0228589A2
Authority
EP
European Patent Office
Prior art keywords
leaf
magnetic
free end
post
printing head
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.)
Granted
Application number
EP86116768A
Other languages
English (en)
French (fr)
Other versions
EP0228589A3 (en
EP0228589B1 (de
Inventor
Sergio Cattaneo
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.)
Bull HN Information Systems Italia SpA
Original Assignee
Bull HN Information Systems Italia SpA
Honeywell Information Systems Italia SpA
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 Bull HN Information Systems Italia SpA, Honeywell Information Systems Italia SpA filed Critical Bull HN Information Systems Italia SpA
Publication of EP0228589A2 publication Critical patent/EP0228589A2/de
Publication of EP0228589A3 publication Critical patent/EP0228589A3/en
Application granted granted Critical
Publication of EP0228589B1 publication Critical patent/EP0228589B1/de
Expired 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
    • B41J2/22—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

  • the present invention relates to a needle printing head and more specifically to an improvement of the actuation armatures of the printing needles.
  • a plurality of magnetic circuits (each of which comprises a magnetic core with a permanent magnet and a demagnetizing coil) are radially arranged round a centre.
  • a leaf spring which is radially arranged round the same centre, constitutes a movable armature that closes the magnetic circuit.
  • the leaf spring is cantilever fixed in the outer area, with respect to the centre, and it extends radially inwards, almost right to the centre, with an actuator arm.
  • a printing needle is fixed to the end of said actuator arm, substantially perpendicular to the leaf spring plane.
  • the magnetic circuit is magnetized owing to the effect of the permanent magnet so that the leaf spring is normally actracted by the magnetic circuit in a bent position and therefore the spring is elastically biased.
  • the demagnetizing coil When the demagnetizing coil is energized the magnetic field generated by the coil neutralizes the field generated by the permanent magnet thus causing the leaf spring to be relased.
  • leaf springs or armatures, are a critical element of said printing heads because, in time, them under go relevant and repeated stress which leads to fatigue failure.
  • said armatures have an adequate elasticity near the cog so as to bend in the plane that is perpendi­cular to the leaf plane, whereas in correspondence with the actuator arm they must be very stiff so as to avoid deformation to occur in the plane that is perpendicular to the leaf plane.
  • the needle printing head which is the object of the present invention where the stiffening of the armature is obtained by means of a stiffening rib extending radially inwards to constitute the actuator arm.
  • This stiffening rib is fixed by means of a cogging groove at the free end of the leaf spring so as to obtain a clamp active on both spring faces.
  • Fig. 1 shows, in partial sectional view, a preferred embodiment of a printing head according to the present invention.
  • the printing head comprises a base circular plate 1 made of magnetic material which is axially magnetized, a toroidal ring 3 made of magnetic material, a plurality of cylindrical magnetic cores which are radially arranged round the central axis of the printing head. A coil is inserted on each one of these magnetic cores.
  • the printing head comprises also a thin circular ring 6 made of magnetic material and a further circular ring 7 made of a material as elastic and magnetic as steel, which is provided with a plurality of elastic leaves that extend inwards towards the central axis of the printing head. Their number is equal to that of the cylindrical magnetic cores and each one of these leaves is radially aligned with a corresponding cylindrical core.
  • Fig. 1 shows one of these elastic leaves which is indicated by reference number 8.
  • the printing heas comprises a circular ring 8 that retains ring 7 and a closing LID (10) which is provided with a nose on the end of which a ruby needle guide (12) is mounted.
  • Each of the elastic leaves, as 8, is provided with a post 15 made of magnetic material which is axially aligned with a corresponding cylindric core (as 4).
  • the various cores, as 4, board 1, and rings 2,3,6,7 form a plurality of magnetic circuits, each of which is closed by a movable armature formed by an elastic leaf and by a post.
  • the elastic leaves 8 extend in a plane which is perpendicular to the axis of the printing head and a small gap, in the order of 0,3 mm, is present between the lower faces of the post as 15 and the top of cores as 4.
  • the magnetic field developed by the permanent magnet 3 normally causes the elastic leaves as 8 to be bent and attracted towards the cores as 4, so that the posts are in contact with cores as 4.
  • the selective energization of the various coils as 5 permits the various magnetic circuits to be selectively demagnetized and the various armatures consituted by leaves as 8 to be selectively release too.
  • each leaf as 8 is provided with an actuation arm which is constituted by a stiffening rib 16 which extends radially towards the printing head axis and is perpendicular to the leaf plane.
  • each stiffening rib a printing needle as 17 is fixed which inserts its Vip in the needle guide ruby 12.
  • Fig. 2 and 3 show in plan and sectional view, and in greater detail, the shape and structure of one the various armatures.
  • the armature consists of a leaf 8 made of elastic and magnetic material that extends radially from an external ring 7 towards the centre of ring 0.
  • leaf 8 is suitably radiused to the ring through radiuses 18, 19.
  • the free end of the leaf is suitably rounded.
  • the magnetic post is provided with a stop collar 18 having the same diameter as the circular opening and a height equal to the thikness of the leaf, which is inserted in the circular opening of the leaf.
  • the diameter of the post is much greater than that of the stop collar, so as to offer the leaf, when these two elements are assembled, a stop ledge.
  • the two elements can be fixed to each other by calking of the stop collar.
  • post 15 has a cylindrical appendix whose diameter is sligthly lesser than that of stop collar 18.
  • a diametral grooves 20 having a suitable width is provided, with orientation towards axis 0 of the printing head. It is designed to receive stiffening rib 16 which acts as an actuation arm.
  • Fig. 4 shows in detail, in front view, siffening rib 16.
  • a stiffening rib consists of a small plate made of a material as resistant as steel, having a suitable thickness (for instance 0,5 mm) and a generically elongated and rectangular shape.
  • Stiffening rib 16 has a straight edge 21 which has been designed to rest on one of the faces of strip 8 and a terminal portion 22 for insertion into groove 20 of Appendix 19.
  • this siffening rib has a groove 23 which separates straight edge 21 from a retaining tooth 24.
  • Groove 23 is intended to receive the distal end of strip 8 which is cogged therein.
  • a printing needle 17 is fixed through brazing or laser welding.
  • Fig. 5 shows in front view stiffening rib 16 Which is set on the armature formed by strip 8 and post 15.
  • rib 16 is fixed and rigidly held in place through either brazing or laser welding.
  • Fig. 6 shows in perpective view the armature completed with the printing needle actuation arm which is constituted by stiffening rib 16 and evidences the various areas along which either brazing or welding of the composing elements can be carried out.
  • stiffening rib of the describe form ensures a strong structural bond resistant to alternate stress.
  • Missing tooth 24 such rotation would be obstacolated mainly by the limited welding area, near point A, which undergoes tensile stress with the possibility of rapid fatigue failure.
  • tooth 24 determines the following two effects: on the one hand it allows the realization of a wider and more winding welding area in correspondence with the cogging, on the other hand it allows the stress to be transmitted directly to rib 16 through tooth 24.
  • the weld material that might be present between tooth 24 and the end of strip 8 undergoes a compression stress rather than a tension stress.

Landscapes

  • Impact Printers (AREA)
EP86116768A 1985-12-06 1986-12-02 Nadeldruckkopf Expired EP0228589B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT23134/85A IT1186414B (it) 1985-12-06 1985-12-06 Testina stampante ad aghi
IT2313485 1985-12-06

Publications (3)

Publication Number Publication Date
EP0228589A2 true EP0228589A2 (de) 1987-07-15
EP0228589A3 EP0228589A3 (en) 1987-10-14
EP0228589B1 EP0228589B1 (de) 1990-03-21

Family

ID=11204145

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86116768A Expired EP0228589B1 (de) 1985-12-06 1986-12-02 Nadeldruckkopf

Country Status (3)

Country Link
EP (1) EP0228589B1 (de)
DE (1) DE3669687D1 (de)
IT (1) IT1186414B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4995742A (en) * 1988-10-18 1991-02-26 Bull Hn Information Systems, Inc. Needle printing head

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4222674A (en) * 1977-05-13 1980-09-16 Kabushiki Kaisha Suwa Seikosha Head portion of a dot printer
US4225250A (en) * 1978-10-10 1980-09-30 Tally Corporation Segmented-ring magnet print head
FR2469288A1 (fr) * 1979-11-16 1981-05-22 Impression Enregistre Resultat Tete d'impression matricielle pour imprimante par points
JPS6079966A (ja) * 1983-10-08 1985-05-07 Citizen Watch Co Ltd バネ蓄勢型印字ヘツドの板バネユニツト
US4531848A (en) * 1982-10-27 1985-07-30 Royden C. Sanders, Jr. Dot matrix print head
US4553864A (en) * 1982-05-04 1985-11-19 Seikosha Co., Ltd. Multicolor cross-hammer printer

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4222674A (en) * 1977-05-13 1980-09-16 Kabushiki Kaisha Suwa Seikosha Head portion of a dot printer
US4225250A (en) * 1978-10-10 1980-09-30 Tally Corporation Segmented-ring magnet print head
FR2469288A1 (fr) * 1979-11-16 1981-05-22 Impression Enregistre Resultat Tete d'impression matricielle pour imprimante par points
US4553864A (en) * 1982-05-04 1985-11-19 Seikosha Co., Ltd. Multicolor cross-hammer printer
US4531848A (en) * 1982-10-27 1985-07-30 Royden C. Sanders, Jr. Dot matrix print head
JPS6079966A (ja) * 1983-10-08 1985-05-07 Citizen Watch Co Ltd バネ蓄勢型印字ヘツドの板バネユニツト

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4995742A (en) * 1988-10-18 1991-02-26 Bull Hn Information Systems, Inc. Needle printing head

Also Published As

Publication number Publication date
IT1186414B (it) 1987-11-26
IT8523134A0 (it) 1985-12-06
DE3669687D1 (de) 1990-04-26
EP0228589A3 (en) 1987-10-14
EP0228589B1 (de) 1990-03-21

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