EP0366981B1 - Dispositif actionneur pour imprimante matricielle - Google Patents
Dispositif actionneur pour imprimante matricielle Download PDFInfo
- Publication number
- EP0366981B1 EP0366981B1 EP19890118784 EP89118784A EP0366981B1 EP 0366981 B1 EP0366981 B1 EP 0366981B1 EP 19890118784 EP19890118784 EP 19890118784 EP 89118784 A EP89118784 A EP 89118784A EP 0366981 B1 EP0366981 B1 EP 0366981B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- actuator
- wave guide
- print hammer
- hammer
- 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 - Lifetime
Links
- 239000011159 matrix material Substances 0.000 title description 7
- 230000035939 shock Effects 0.000 claims description 20
- 239000007787 solid Substances 0.000 claims description 12
- 239000000919 ceramic Substances 0.000 claims description 6
- 230000006835 compression Effects 0.000 claims description 5
- 238000007906 compression Methods 0.000 claims description 5
- 230000001747 exhibiting effect Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 208000032365 Electromagnetic interference Diseases 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003094 perturbing effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
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
- B41J2/295—Actuators for print wires using piezoelectric elements
Definitions
- This invention relates to matrix printers and, more particularly, to a matrix printer that is shock-driven by a piezoelectric actuator.
- Piezoelectric driven impact printers are known in the art. Compared with conventional electromagnetic actuated impact printers, they exhibit higher printing speeds, lower energy consumption and less generation of heat. Nevertheless, most piezoelectric driven dot matrix printers exhibit significant deficiencies in their operation or structure. While some have been embodied into commercial printers, in general, they require significant maintenance and adjustment over the lifetime of the printer.
- a piezoelectric actuator is employed to induce a surface wave in a high friction elastomer which is, in turn, coupled to a pressure contact plate/print wire combination.
- a surface wave is generated in the elastomer material which causes the print wire to be extended.
- Kitagawa in U.S. Patent 4,613,241 has a shock-wave operated, wire matrix printer wherein each wire is coupled to a sealed flexible container which contains opposed electrodes and a pressure transmitting medium. A discharge is caused to occur between the electrodes so that the container expands and drives the print wire towards the paper.
- This construct overcomes some problems of the prior art but requires the use of a continuous, spark-type discharge which not only creates electro-magnetic interference problems but also creates lifetime limiting problems for the actuator.
- Patent Abstract of Japan, Volume 12, Number 321 (M-736) 31/08/88 & JP-A-63 89 353 discloses an impact printer which comprises a piezo-electric element.
- the piezo-electric element causes a displacement motion which is transmitted from the second to the first plate spring and that plate spring carries out free flying motion. That printer is actuated by the physical movement of its actuator.
- An impact printer actuator which includes shock wave generating means, a print hammer, and solid wave guide means interposed between the shock wave generator and print hammer.
- the solid wave guide means acts to transmit a shock wave from the shock wave generator to the print hammer to cause its movement towards a substrate upon which printing is to occur.
- the shock wave generator comprises a piezoelectric actuator, which actuator is held in compression by a frame that prevents any substantial longitudinal movement thereof.
- sense means are connected to the piezoelectric actuator for detecting, after an actuation, the return of the hammer into contact with the wave guide means. In response to that detection, the sense means provides a signal which enables operation of the shock wave generator.
- an electrostrictive or piezoelectric ceramic actuating element 10 is fixed to middle arm 12 of frame 14. Electrical conductors 11 provide energizing signals to actuating element 10.
- Frame 14 is E-shaped and has upper arm 16 and lower arm 18.
- a beam 20 extends from upper arm 16 to lower arm 18 and is attached thereto by cap screws 22 and 24.
- An extension 26 from beam 20 is equidistantly located between arms 16 and 18 and bears upon actuating element 10 to maintain it in compression. When cap screws 22 and 24 are tightened, beam 20 is caused to flex so that extension 26 bears upon element 10 and compresses it against middle arm 12.
- a print hammer 30 is mounted on leaf spring 32 and has one end which bears against wave guide portion 28. The other end of print hammer 30 has attached to it a print wire 34 which extends through wire guide 36.
- Spring 32 is rigidly attached to a fixed point 38.
- the preferred shape of wave guide portion 28 is conical so as to assure maximum energy transfer to print hammer 30.
- the conical structure acts to concentrate the wave energy so that it is most intense at the point of contact between wave guide portion 28 and print hammer 30.
- the mass of beam 20 extension 26 and wave guide portion 28 are approximately made equal to the mass of print hammer 30.
- beam 20 and frame 14 are constructed of a material, e.g. steel, aluminum which provides substantial stiffness so that when actuating element 10 is energized, little or no expansion of its length occurs and the energy induced into extension 26 is essentially of a pure shock wave nature.
- Actuating element 10 is preferably, a piezoelectric actuator of the multilayer type.
- Such an actuator includes a number of piezoelectric plates, stacked together with internal electrodes so that an applied voltage thereacross causes the actuator to expand in its longitudinal direction. The plates are laminated one upon the other and provide substantial force and displacement when energized.
- Such a structure is schematically shown in FIG. 3 and comprises a plurality of ceramic layers 50 with interspersed electrodes 52, 54, etc.
- the field induced in the ceramic plates by an applied voltage has the direction shown by arrow 56 and causes the actuator to expand in the directions shown by arrow 58.
- a voltage is applied across electrodes 52 and 54, a stress wave is generated in the actuator 10 through the known d33 piezoelectric effect.
- An alternate actuator structure as shown in Fig. 4 and comprises elongated ceramic plates 60 with interspersed electrodes 62.
- the field direction is as shown by arrows 64 and the expansion direction occurs as shown by arrows 66.
- a stress wave created by the application of a voltage across electrodes 62 is generated by the d31 piezoelectric effect. Since, the d33 piezoelectric effect is substantially larger than the d31 piezoelectric effect, the actuator structure shown in Fig. 3 is preferred.
- Still another appropriate actuator which is suitable, is an electrostrictive actuator, preferably of the PMN variety e.g., a Pb, Mg, Niobate composition.
- Figs. 1 and 2 commences when a voltage pulse is applied to actuator 10.
- the voltage pulse creates a shock wave therein which is generated by the fast response characteristics of the actuator. Since however, actuator 10 is constrained from expansion by middle arm 12 of frame 14 and extension 26 from beam 20, an induced shock wave propagates into both arm 12 and extension 26.
- the portion of the shock wave which propagates into extension 26, enters solid conical wave guide portion 28 and is caused to converge to its reduced cross section area.
- Leaf spring 32 maintains print hammer 30 in contact with wave guide portion 28.
- the induced shock wave appears at the reduced cross section of wave guide portion 28, it is transmitted to print hammer 30.
- hammer 30 moves rapidly to the left in the direction shown by arrow 60.
- Print wire 34 is thus caused to move through guide 36 and to strike a ribbon, paper and platen in sequence (not shown). Afterwards, hammer 30 is caused to return to wave guide portion 28 due to collision rebound forces and the restoration force exerted by spring 32. When print hammer 30 returns to its original position and contacts wave guide portion 28, it is adapted to be fired again.
- actuator 10 is energized by hammer drive circuit 70, that is, in turn, operated by printer control 72.
- printer control 72 As can be understood from an examination of Fig. 1, when hammer 30 returns and impacts upon wave guide portion 28, a shock wave is initiated which travels through beam 20 and extension 26 into actuator 10. The presence of the induced shock wave in actuator 10 is sensed across contacts 11 and is fed through gate 76 to hammer return sense amplifier 74 whose output is, in turn, fed to printer control 72 via conductor 78.
- Fig. 6 shows a trace of the voltage applied to actuator 10 and the voltage in actuator 10, induced by the impact of print hammer 30 on wave guide portion 28.
- a voltage pulse 80 is initially applied to actuator 10 by hammer drive 70.
- the impact induces pulse voltage 82 in actuator 10, which voltage appears across conductors 11 (Fig. 1).
- pulse signal 80 from printer control 72 actuates hammer drive 70 to cause a shock wave to be generated in actuator 10
- the pulse output from printer control 72 is inverted by inverter 75 and turns off gate 76. This prevents the high voltage output of hammer drive 70 from perturbing hammer return sense amplifier 74.
- gate 76 is opened and awaits the appearance of pulse 82 (Fig. 6).
- hammer return sense amplifier 74 Upon detecting pulse 82, hammer return sense amplifier 74 generates a signal which indicates to printer control 72 that the circuit is ready again to be operated.
- Beam 20, extension 26 and middle arm 12 keep actuator element 10 under compression. This protects element 10 from failure due to induced tensile stress and from the impact stress due to the collision of print hammer 30 with wave guide portion 28 during its return motion. Additionally, hammer 30 flies away from wave guide 28 at a high initial speed, without delay, thereby enabling high speed print operation.
- Spring 32 is made flexible and provides sufficient force to return print hammer 30 back to its original home position so that it bears on wave guide 28. The print energy is adjustable through change of the mass of hammer 30 and allows for changes to accommodate various dot and wire size printing applications.
- Actuator 10 is further usable as a sensor to detect the hammer return and to provide a "print ready" signal to the printer control so that maximum speed can be achieved without additional control systems.
- frame 14 is shown in the form of an E, it could be shaped as a C with one extremity of actuator 10 bearing directly on the vertical extent of the C shape (Fig. 7).
Landscapes
- Impact Printers (AREA)
Claims (15)
- Imprimante à percussion comprenant :
un dispositif actionneur (10);
un marteau d'impression (30);
caractérisée en ce que
ledit dispositif actionneur (10) génère une onde de choc dans un sens prédéterminé, ledit dispositif actionneur étant empêché de se déplacer dans ledit sens prédéterminé, et
ladite imprimante comprend, de plus :
un support solide de guide d'ondes (28) interposé entre ledit dispositif actionneur (10) et ledit marteau d'impression (30) pour transmettre ladite onde de choc au dit marteau d'impression (30) pour le déplacer. - Imprimante à percussion selon la revendication 1, dans lequel ledit dispositif actionneur (30) est sélectionné dans un groupe comprenant des actionneurs piézoélectriques et des actionneurs à électrostriction.
- Invention selon la revendication 1 ou 2, comprenant de plus :
un cadre (12, 14) pour positionner ledit support solide de guide d'ondes (20, 26, 28) contre ledit dispositif actionneur (10) afin de maintenir ledit dispositif actionneur en compression. - Invention selon la revendication 1, 2 ou 3, dans laquelle ledit cadre exerce une force de compression suffisante contre ledit dispositif actionneur (10) pour éviter tout déplacement longitudinal de celui-ci.
- Invention selon la revendication 1 2, 3 ou 4, dans laquelle ledit marteau d'impression (30) est soutenu par un support flexible (32) et se déplace selon un mouvement de vol libre dans les limites de la contrainte exercée par ledit support flexible, après avoir subi ladite onde de choc provenant du dit support solide de guide d'ondes (28).
- Invention selon l'une quelconque des revendications précédentes, dans laquelle le dit support flexible (32) comprend :
un ressort (32) pour incliner ledit marteau d'impression (30) contre un point de contact avec ledit support solide de guide d'ondes (28). - Invention selon l'une quelconque des revendications précédentes, dans laquelle ledit support solide de guide d'ondes (28) est façonné en sorte de concentrer l'onde de choc sur ledit point de contact.
- Invention selon l'une quelconque des revendications précédentes, dans laquelle ladite partie façonnée du dit support solide de guide d'ondes (28) est conique et à une portion de section transversale réduite qui est au contact du dit marteau d'impression (30).
- Invention selon l'une quelconque des revendications précédentes, dans laquelle ledit actionneur (10) est de forme allongée, ledit actionneur étant formé de plaques céramiques disposées en couche (50, 60) avec des électrodes intercalées (52, 54, 62), les dites plaques céramiques ayant leurs surfaces principales orientées perpendiculairement par rapport à la dimension oblongue du dit actionneur (10), ce qui induit la génération d'une onde de choc la long de la dimension oblongue du dit actionneur (10) lorsque les dites électrodes sont excitées.
- Invention selon l'une quelconque des revendications précédentes, dans laquelle une aiguille d'impression est solidement fixée au dit marteau d'impression (30).
- Imprimante à percussion comprenant :
un marteau d'impression;
un cadre en forme d'arc rigide (14) comprenant une paire de bras opposés (16, 18);
un actionneur (10) positionné entre les dits bras (16, 18) et étant de forme allongée;
une pièce de jonction (20, 26) pour soutenir ledit actionneur;
un dispositif d'inclinaison du marteau d'impression (32);
un dispositif (11) pour exciter ledit actionneur (10)
caractérisée en ce que
ladite pièce de jonction (20, 26) relier les deux bras pour maintenir ladite dimension oblongue du dit actionneur piézoélectrique (10) en compression contre ledit cadre (14) afin d'empêcher tout déplacement du dit actionneur le long de sa dimension oblongue, ladite pièce de jonction (20) étant munie d'une portion de guide d'ondes (28) adjacente à l'une des extrémités de ladite dimension oblongue du dit actionneur (10);
ledit dispositif d'inclinaison du marteau d'impression (32) inclinant de manière résiliente ledit marteau d'impression (30) contre ladite portion de guide (28). - Invention selon la revendication 11, dans laquelle ledit cadre (14) est en forme de "E", ledit actionneur (10) étant positionné dans le bras centrale (12) du dit "E".
- Invention selon la revendication 11 ou 12, dans laquelle ladite pièce de jonction (20, 26) s'étend entre le bras supérieur (16) et le bras inférieur (18) du dit cadre en forme de "E" (14).
- Invention selon la revendication 11, dans laquelle ledit cadre (14) est en forme de "C", ladite pièce de jonction (20, 26) s'étendent entre le bras supérieur (16) et le bras inférieur (18) du dit "C', et ledit actionneur étant maintenu entre ladite pièce de jonction (20, 26) et ledit cadre en forme de "C" (14).
- Invention selon l'une quelconque des revendications précédentes, comprenant de plus :
un dispositif de détection (11, 76, 74) relié au dit actionneur (10) pour détecter, après actionnement, le retour du dit marteau d'impression (30) au contact du dit support solide de guide d'ondes (28) et pour transmettre, en réponse à cette détection,un signal (80) qui autorise le fonctionnement du dit dispositif générateur (10, 11).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US26453588A | 1988-10-31 | 1988-10-31 | |
US264535 | 1988-10-31 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0366981A2 EP0366981A2 (fr) | 1990-05-09 |
EP0366981A3 EP0366981A3 (en) | 1990-09-19 |
EP0366981B1 true EP0366981B1 (fr) | 1994-02-09 |
Family
ID=23006487
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19890118784 Expired - Lifetime EP0366981B1 (fr) | 1988-10-31 | 1989-10-10 | Dispositif actionneur pour imprimante matricielle |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0366981B1 (fr) |
JP (1) | JPH02130154A (fr) |
DE (1) | DE68913005T2 (fr) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5981181A (ja) * | 1982-11-01 | 1984-05-10 | Nec Corp | 電歪式ワイヤ−ドツトプリンタ用印字ヘツド |
US4480934A (en) * | 1982-12-20 | 1984-11-06 | International Business Machines Corporation | Ballistic print wire actuator using a telescopic armature |
US4613241A (en) * | 1984-01-05 | 1986-09-23 | Nec Corporation | Printing mechanism for dot matrix printers |
JPS61167582A (ja) * | 1985-01-21 | 1986-07-29 | Nec Corp | 印字ハンマ |
JPS61225067A (ja) * | 1985-03-29 | 1986-10-06 | Nec Corp | 印字ハンマ |
JPS61233559A (ja) * | 1985-04-09 | 1986-10-17 | Nec Corp | 圧電式ハンマ |
JPS6354257A (ja) * | 1986-08-25 | 1988-03-08 | Nec Corp | 圧電アクチユエ−タ |
JPS6389353A (ja) * | 1986-10-02 | 1988-04-20 | Nec Corp | 印字ヘツド |
JPS63130174A (ja) * | 1986-11-07 | 1988-06-02 | エヌ・シー・アール・インターナショナル・インコーポレイテッド | アクチユエ−タ・ユニツト |
JPS63144054A (ja) * | 1986-12-05 | 1988-06-16 | Nec Corp | 印字ヘツド |
-
1989
- 1989-08-11 JP JP20711689A patent/JPH02130154A/ja active Pending
- 1989-10-10 EP EP19890118784 patent/EP0366981B1/fr not_active Expired - Lifetime
- 1989-10-10 DE DE1989613005 patent/DE68913005T2/de not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH02130154A (ja) | 1990-05-18 |
EP0366981A2 (fr) | 1990-05-09 |
DE68913005T2 (de) | 1994-08-04 |
EP0366981A3 (en) | 1990-09-19 |
DE68913005D1 (de) | 1994-03-24 |
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