EP0366981B1 - Matrix printer actuator - Google Patents
Matrix printer actuator 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).
Description
- 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.
- In U.S. Patent 4,589,786 to Fukui et al, both single and dual piezoelectric driven, wire, dot matrix printers are described which employ a complicated two-stage differential linkage to achieve wire displacement amplification. The motion of the linkage which is required to achieve amplification of the movement of the piezoelectric actuator consumes significant mechanical energy, restricts the distance of wire travel and causes the printing force to drop off when print wire travel exceeds a certain distance.
- Another piezoelectrically driven print mechanism is shown in U.S. Patent 4,547,086 to Matsumoto et al. The structure described therein employs opposed piezoelectric actuators whose combined movements cause a lever, on which is mounted a print wire, to pivot in the direction of the paper on which printing is to occur. This system suffers the same drawbacks as the Fukui et al system. Similar mechanical piezoelectric driven print wire mechanisms are shown in Japanese Patents 59-103766 and 59-103767.
- In Japanese Patents 59-215871 and 60-38172 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. When the piezoelectric actuator is energized, a surface wave is generated in the elastomer material which causes the print wire to be extended.
- In U.S. Patent 4,193,703 to Sakmann, still another type of piezoelectrically driven print mechanism is shown wherein a print wire is attached to a buckling spring. When a piezoelectric element coupled to the spring is energized, the spring extends the print wire. One embodiment of Sakmann's print mechanism employs a print wire which rests on but is not connected to the buckling spring. This, to some extent, overcomes the limitation of limited print wire movement characteristic of other print wire actuators. However, the Sakmann actuator is still dependent upon the amount of movement of the piezoelectric actuator which is, by its nature, limited.
- 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. - Accordingly, it is an object of this invention to provide a piezoelectrically driven, print wire actuator wherein the length of travel of the print wire is not restricted by the actuator.
- It is another object of this invention to provide a piezoelectrically operated print wire actuator wherein the amount of movement of the piezoelectric element does not act as a limiting factor on the movement of the print wire.
- It is still a further object of this invention to provide a piezoelectrically operated print wire actuator of simple and inexpensive design.
- It is still a further object of this invention to provide a piezoelectrically operated print wire actuator which consumes minimum power.
- These objects are solved by the solution given in the characterizing parts of the main independent claims. Further advantageous embodiments of the present invention are laid down in the subclaims.
- An impact printer actuator is described 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.
- In a preferred embodiment, the shock wave generator comprises a piezoelectric actuator, which actuator is held in compression by a frame that prevents any substantial longitudinal movement thereof. In a further preferred embodiment, 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.
- The invention will be shown in more detail in the following description in accordance with the drawing in which embodiments are shown and in which:
- Fig. 1
- is a side view of a print wire actuator which embodies the invention;
- Fig. 2
- is an exploded, isometric view of the print wire actuator shown in Fig. 1;
- Fig. 3
- is a schematic showing of a piezoelectric actuator usable with the invention hereof;
- Fig. 4
- is a schematic showing of another type of piezoelectric actuator usable with the invention hereof;
- Fig. 5
- is a high level block diagram of a circuit for energizing the piezoelectric actuator;
- Fig. 6
- is a plot of voltage applied to the piezoelectric actuator and the voltage induced by the impact force of the hammer return on the actuator; and
- Fig. 7
- shows a further embodiment of the frame.
- Turning now to Figs. 1 and 2, an electrostrictive or piezoelectric ceramic actuating
element 10 is fixed tomiddle arm 12 offrame 14. Electrical conductors 11 provide energizing signals to actuatingelement 10.Frame 14 is E-shaped and hasupper arm 16 andlower arm 18. Abeam 20 extends fromupper arm 16 tolower arm 18 and is attached thereto bycap screws extension 26 frombeam 20 is equidistantly located betweenarms element 10 to maintain it in compression. Whencap screws beam 20 is caused to flex so thatextension 26 bears uponelement 10 and compresses it againstmiddle arm 12. - Immediately
adjacent extension 26 is solidwave guide portion 28. Aprint hammer 30 is mounted onleaf spring 32 and has one end which bears againstwave guide portion 28. The other end ofprint hammer 30 has attached to it aprint wire 34 which extends throughwire guide 36.Spring 32 is rigidly attached to afixed point 38. - As can be better seen in Fig. 2, the preferred shape of
wave guide portion 28 is conical so as to assure maximum energy transfer to printhammer 30. The conical structure acts to concentrate the wave energy so that it is most intense at the point of contact betweenwave guide portion 28 and printhammer 30. In the preferred embodiment, the mass ofbeam 20extension 26 andwave guide portion 28 are approximately made equal to the mass ofprint hammer 30. In addition,beam 20 andframe 14 are constructed of a material, e.g. steel, aluminum which provides substantial stiffness so that when actuatingelement 10 is energized, little or no expansion of its length occurs and the energy induced intoextension 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 ofceramic layers 50 with interspersedelectrodes arrow 56 and causes the actuator to expand in the directions shown byarrow 58. When a voltage is applied acrosselectrodes actuator 10 through the known d₃₃ piezoelectric effect. - An alternate actuator structure as shown in Fig. 4 and comprises elongated
ceramic plates 60 with interspersedelectrodes 62. In this instance, the field direction is as shown byarrows 64 and the expansion direction occurs as shown byarrows 66. As is known, a stress wave created by the application of a voltage acrosselectrodes 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.
- The operation of the matrix printer actuator shown in 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 bymiddle arm 12 offrame 14 andextension 26 frombeam 20, an induced shock wave propagates into botharm 12 andextension 26. The portion of the shock wave which propagates intoextension 26, enters solid conicalwave guide portion 28 and is caused to converge to its reduced cross section area.Leaf spring 32 maintainsprint hammer 30 in contact withwave guide portion 28. Thus, when the induced shock wave appears at the reduced cross section ofwave guide portion 28, it is transmitted to printhammer 30. As aresult hammer 30 moves rapidly to the left in the direction shown byarrow 60.Print wire 34 is thus caused to move throughguide 36 and to strike a ribbon, paper and platen in sequence (not shown). Afterwards, hammer 30 is caused to return towave guide portion 28 due to collision rebound forces and the restoration force exerted byspring 32. Whenprint hammer 30 returns to its original position and contacts waveguide portion 28, it is adapted to be fired again. - Referring now to Fig. 5,
actuator 10 is energized byhammer drive circuit 70, that is, in turn, operated byprinter control 72. As can be understood from an examination of Fig. 1, whenhammer 30 returns and impacts uponwave guide portion 28, a shock wave is initiated which travels throughbeam 20 andextension 26 intoactuator 10. The presence of the induced shock wave inactuator 10 is sensed across contacts 11 and is fed throughgate 76 to hammerreturn sense amplifier 74 whose output is, in turn, fed toprinter control 72 via conductor 78. - Fig. 6 shows a trace of the voltage applied to
actuator 10 and the voltage inactuator 10, induced by the impact ofprint hammer 30 onwave guide portion 28. In specific, avoltage pulse 80 is initially applied toactuator 10 byhammer drive 70. Whenhammer 30, on rebound, impacts uponsolid wave guide 28, the impact inducespulse voltage 82 inactuator 10, which voltage appears across conductors 11 (Fig. 1). - When pulse signal 80 from
printer control 72 actuates hammer drive 70 to cause a shock wave to be generated inactuator 10, the pulse output fromprinter control 72 is inverted byinverter 75 and turns offgate 76. This prevents the high voltage output of hammer drive 70 from perturbing hammerreturn sense amplifier 74. When the output ofprinter control 72 falls,gate 76 is opened and awaits the appearance of pulse 82 (Fig. 6). Upon detectingpulse 82, hammerreturn sense amplifier 74 generates a signal which indicates toprinter control 72 that the circuit is ready again to be operated. -
Beam 20,extension 26 andmiddle arm 12 keepactuator element 10 under compression. This protectselement 10 from failure due to induced tensile stress and from the impact stress due to the collision ofprint hammer 30 withwave guide portion 28 during its return motion. Additionally, hammer 30 flies away fromwave 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 returnprint hammer 30 back to its original home position so that it bears onwave guide 28. The print energy is adjustable through change of the mass ofhammer 30 and allows for changes to accommodate various dot and wire size printing applications. Furthermore, since printing is performed while the hammer and wire assembly operate in free flight motion, the applied print force to the print medium is relatively constant over a wide range of printing strokes.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. Finally, whileframe 14 is shown in the form of an E, it could be shaped as a C with one extremity ofactuator 10 bearing directly on the vertical extent of the C shape (Fig. 7).
Claims (15)
- An impact printer comprising:
actuator means (10);
print hammer means (30);
characterized in that
said actuator means (10) generates a shock wave in a predetermined direction, said actuator means restrained from movement in said predetermined direction, and
said printer further comprising:
solid wave guide means (28) interposed between said actuator means (10) and said print hammer means (30) for transmitting said shock wave to said print hammer means (30) to cause the movement thereof. - An impact printer as defined in Claim 1 wherein said actuator means (30) is selected from the group consisting of piezoelectric and electrostrictive actuators.
- The invention as defined in Claim 1 or 2 further comprising:
frame means (12, 14,) for positioning said solid wave guide means (20, 26, 28) against said actuator means (10) to maintain said actuator means in compression. - The invention as defined in Claim 1, 2 or 3 wherein said frame means exerts sufficient compressive force against said actuator means (10) to prevent substantial longitudinal movement thereof.
- The invention as defined in Claim 1, 2, 3 or 4 wherein said print hammer means (30) is supported on flexible means (32) and moves in free flight motion as constrained by said flexible means, upon experiencing said shock wave from said solid wave guide means (28).
- The invention as defined in any one of the preceding claims wherein said flexible means (32) comprises:
spring means (32) for biasing said print hammer means (30) against a point of contact with said solid wave guide means (28). - The invention as defined in any one of the preceding claims wherein said solid wave guide means (28) is shaped to focus said shock wave to said point of contact.
- The invention as defined in any one of the preceding claims wherein said shaped part of said solid wave guide means (28) is conical and has a reduced cross section portion which contacts said print hammer (30).
- The invention as defined in any one of the preceding claims wherein said actuator (10) has an elongated dimension, said actuator being comprised of laminated ceramic plates (50, 60) with interspersed electrodes (52, 54, 62), said ceramic plates having major faces oriented orthogonally to said elongated dimension, whereby said actuator creates a shock wave along said elongated dimension when said electrodes are energized.
- The invention as defined in any one of the preceding claims wherein said print hammer (30) has rigidly attached thereto, a print wire (34).
- An impact printer comprising:
a print hammer;
arcuately rigid frame means (14) including a pair of opposed arms (16, 18);
an actuator (10) positioned between said arms (16, 18) and exhibiting an elongated dimension;
beam means (20,26) for supporting said actuator;
print hammer biasing means (32);
means (11) for energizing said actuator (10)
characterized in that
said beam means (20, 26) spanning said arms for holding said elongated dimension of said piezoelectric actuator (10) in compression against said frame means (14) to prevent movement of said actuator along its elongated dimension, said beam means (20) provided with a wave guide portion (28) adjacent one end of said elongated dimension of said actuator (10);
said print hammer biasing means (32) resiliently biasing said print hammer (30) against said wave guide portion (28). - The invention as defined in Claim 11 wherein said frame means (14) is E-shaped with said actuator (10) positioned in the middle arm (12) of said E.
- The invention as defined in Claim 11 or 12 wherein said beam means (20, 26) spans across upper (16) and lower arms (18) of said E-shaped frame means (14).
- The invention as defined in Claim 11 wherein said frame means (14)is C-shaped and said beam means (20, 26) spans across the upper (16) and lower arms (18) of said C and said actuator is held between said beam means (20, 26) and said C-shaped frame means (14).
- The invention as defined in any one of the preceding claims further comprising:
sense means (11, 76, 74) connected to said actuator (10) for detecting, after an actuation, the return of said hammer means (30) into contact with said solid wave guide means (28), and, in response, for providing a signal (80) which enables the operation of said generating means (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 (en) | 1990-05-09 |
EP0366981A3 EP0366981A3 (en) | 1990-09-19 |
EP0366981B1 true EP0366981B1 (en) | 1994-02-09 |
Family
ID=23006487
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19890118784 Expired - Lifetime EP0366981B1 (en) | 1988-10-31 | 1989-10-10 | Matrix printer actuator |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0366981B1 (en) |
JP (1) | JPH02130154A (en) |
DE (1) | DE68913005T2 (en) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5981181A (en) * | 1982-11-01 | 1984-05-10 | Nec Corp | Printing head for electrostrictive-type wire dot printer |
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 (en) * | 1985-01-21 | 1986-07-29 | Nec Corp | Printing hammer |
JPS61225067A (en) * | 1985-03-29 | 1986-10-06 | Nec Corp | Printing hammer |
JPS61233559A (en) * | 1985-04-09 | 1986-10-17 | Nec Corp | Piezoelectric type hammer |
JPS6354257A (en) * | 1986-08-25 | 1988-03-08 | Nec Corp | Piezoelectric actuator |
JPS6389353A (en) * | 1986-10-02 | 1988-04-20 | Nec Corp | Printing head |
JPS63130174A (en) * | 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 | Actuator-unit |
JPS63144054A (en) * | 1986-12-05 | 1988-06-16 | Nec Corp | Printing head |
-
1989
- 1989-08-11 JP JP20711689A patent/JPH02130154A/en active Pending
- 1989-10-10 DE DE1989613005 patent/DE68913005T2/en not_active Expired - Fee Related
- 1989-10-10 EP EP19890118784 patent/EP0366981B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
DE68913005D1 (en) | 1994-03-24 |
EP0366981A2 (en) | 1990-05-09 |
DE68913005T2 (en) | 1994-08-04 |
EP0366981A3 (en) | 1990-09-19 |
JPH02130154A (en) | 1990-05-18 |
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