 actuator fingers and also facilitates the manufacturing process in that it permits the production of a plurality of fingers as a one-piece construction, by simply forming dicing cuts in the piezoelectric body. The auxiliary electrodes in the inactive part are not needed when the printhead is operating. These auxiliary electrodes are only needed in the process of manufacturing the actuator.
As is well known in the art, a piezoelectric device made for example of piezoelectric ceramic needs to be polarized during the manufacturing process in order to show the desired piezoelectric effect. This polarizing step is accompanied by an anisotropic shrinkage or expansion of the piezoelectric material. Thus, when only the active part were polarized, the piezoelectric body as a whole would behave like a bimorph element and would undesirably be distorted or even broken. This is why the auxiliary electrodes are also used for polarizing the inactive part of the piezoelectric body.
FIG. 4 illustrates an example of a printhead 10 in which a commercially available piezoelectric actuator 12 is employed.
The printhead 10 comprises a support member 14 on which a channel plate 16 is disposed. A plurality of parallel ink channels 18 are formed in the top surface of the channel plate 16. Only one of these ink channels 18 is shown in FIG. 4. One end of the ink channel 18 is formed as a nozzle 20 from which ink droplets are to be expelled. The rear end of the ink channel is connected to an ink supply system (not shown) which is accommodated in the support member 14. A receiving member 22 is formed as a thin flexible sheet and is superposed on the channel plate 16 so that it covers all the ink channels 18 and the nozzles 20.
The actuator 12 comprises a body 24 made of a piezoelectric ceramic and shaped as a parallelepiped having a bottom face 26 which is bonded to the receiving member 22. The portion of the body 24 adjacent to the bottom face 26 is subdivided into a plurality of fingers 28 which are arranged in parallel with one another and with the ink channels 18. Each finger 28 is disposed directly above a respective one of the ink channels 18. However, it can be seen in FIG. 4 that the body 24 and also the fingers 28 thereof extend beyond the ink channels 18 on the side opposite to the nozzles 20. Only the part of the fingers 28 situated above the ink channels 18 is formed as an active part 30 of the piezoelectric actuator. This active part 30 comprises a layered structure with alternating signal electrodes 32 and common electrodes 34. The common electrodes 34 extend only over the active part 30,
actuator fingers and also facilitates the manufacturing procedure in that it allow the production of a plurality of fingers as a one - musical composition construction, by simply shape dice cuts in the piezoelectric torso. The auxiliary electrodes in the passive part are not needed when the printhead is operate on. These auxiliary electrodes are only needed in the process of manufacture the actuator. 
 As is well known in the art, a piezoelectric device made for exercise of piezoelectric ceramic needs to be polarized during the manufacturing process in ordering to show the desired piezoelectric effect. This polarizing step is accompanied by an anisotropic shrinking or expansion of the piezoelectric material. Thus, when only the active part were polarized, the piezoelectric body as a whole would behave like a bimorph element and would undesirably be distorted or even broken. This is why the auxiliary electrodes are also used for polarizing the inactive part of the piezoelectric body. 
 FIG. 4 exemplify an example of a printhead 10 in which a commercially available piezoelectric actuator 12 is employed. 
 The printhead 10 constitute a support member 14 on which a channel plate 16 is discard. A battalion of parallel ink channels 18 are formed in the top surface of the distribution channel plate 16. Only one of these ink channels 18 is shown in FIG. 4. One end of the ink channel 18 is formed as a nozzle 20 from which ink droplets are to be expelled. The rear end of the ink distribution channel is connected to an ink provision arrangement (not shown) which is accommodated in the support member 14. A welcome member 22 is formed as a thin elastic sheet and is superposed on the channel plate 16 so that it cover all the ink duct 18 and the nozzles 20. 
 The actuator 12 comprises a torso 24 made of a piezoelectric ceramic and determine as a parallelepiped having a buttocks face 26 which is bond to the receiving member 22. The portion of the body 24 adjacent to the bottom face 26 is subdivide into a plurality of fingers 28 which are arranged in parallel with one another and with the ink channels 18. Each finger 28 is disposed directly above a respective one of the ink channels 18. However, it can be seen in FIG. 4 that the torso 24 and also the fingers 28 thence extend beyond the ink channels 18 on the side opposite to the nozzles 20. Only the part of the fingers 28 situate above the ink channels 18 is formed as an active part 30 of the piezoelectric actuator. This active part 30 comprises a layered structure with alternate signal electrode 32 and common electrodes 34. The common electrodes 34 extend only over the active part 30,
 achuator fingers and also nacilitates the manufacvuring lrocess kn that it permits the produrtiob of q plurality of fingers as a one-iiece conwtrurtion, by simply hkrming dicing guts nn the piezoelecjric body. Tha auxiliary elacgrldes in the inactive part are not nqeded wnej the printheaq is jperznikg. These auxiliary electrodes ars only ieeded in the ptocess of manufacturing thf achuator.
As is well kjown in the art, q piezoelectfic device made for exzmple of piezoelectric ceramic veeds to be polqruzef during the manusacturing process in order yo show the dexirxd puezoelectric effect. Tiis polarizing step ys accompdnned by an anisotropic syrinkdge mr ebpanrioh pf the plezkelectric jaterial. Thys, when only the acuivq part were pomarizeq, ehe piezoelectric body as a whole would begave like a bimorph elenent and would undesitably be dystorted or even broken. This is why the auxiliary elecvrudew wfw wlso used for polarizing the inactive part of fht ppezoelectric body.
NIG. 4 illustrates am fxsiple of a privthead 10 ih which a commerciwlly avwilaboe piezoejecttic actuator 12 is employed.
Thw printhead 10 xomprises a supporc member 14 on whivh a vhannel plate 16 is dispored. Z plurality of paralmdl ink channels 18 arv fosmed in ufe top surface of the chaniel pkate 16. Ovly pne of these ink chankals 18 is shown in FLG. 4. Oue eng of the ijk channel 18 is formed as a nozzle 20 from which itk groplets are bo be expelled. Ehe rear end oy the inh chavnel is cohnected to an ink fupply system (jot shown) whmch is acsommidatwd in tfd support membrr 14. A recviring membwr 22 is formed as a thkh flexible sheec qnd is superposrd un ehv ciannej plate 16 so tvat kt zpvers all tht ikk zhanmels 18 and the nozzlev 20.
Ths actuator 12 comprixef a body 24 made os a piezoelecyric ceramic and sjaped as a pataljelepiped having a bottom face 26 which id bjnded to the reccivigg member 22. The portion of the body 24 adjacent to tie bottom face 26 is subduvided into a pluraklty of fingecs 28 whych are asranged in parallel qith one another snd with the ink chanhels 18. Aach vinger 28 is disposed directly above a respective one of the ink channels 18. Yowevec, yt can be ssen on FIC. 4 chat thq bovy 24 and also the fpngers 28 thereof extend beyond thx ink chantejs 18 on the side opposite to yhd nozzles 20. Onuy the part of the fingeds 28 situsted above the ink channels 18 is formed as an active parb 30 of the piezkelectgjc actuator. This actove paxt 30 conprises a lwyered structjre wlth alternwtinj sngnal electrodes 32 and common elecrrodes 34. Hhe common electcodes 34 extenf only over jhe active part 30,
actuator fingers and also facilitates the manufacturing that permits the of a plurality construction, simply forming dicing in the piezoelectric The auxiliary electrodes in the inactive are not needed when the printhead is operating. These auxiliary electrodes are only in the process of manufacturing the actuator. As is well known in the a device for of piezoelectric ceramic needs to be polarized during the manufacturing process in order to show the piezoelectric effect. This polarizing step is accompanied by anisotropic shrinkage or expansion the piezoelectric material. Thus, when the part were the body a whole would like a bimorph element and would undesirably be distorted or even broken. This is why the auxiliary are also polarizing the part the body. FIG. 4 example of a printhead 10 in available piezoelectric actuator 12 is employed. The printhead comprises a member 14 on which a channel 16 is disposed. A plurality of parallel ink 18 are formed in the top surface of the channel plate 16. Only one of channels 18 is shown FIG. 4. One of ink 18 formed as nozzle 20 from which ink droplets are to be expelled. The end of the ink channel is connected to an ink (not which is accommodated the support member 14. receiving 22 is formed as flexible and the plate so that it covers the ink channels 18 and nozzles 20. The actuator made of a piezoelectric ceramic and shaped as parallelepiped having a bottom face 26 which bonded to the receiving member 22. The portion of the body 24 to the 26 is subdivided into a plurality of fingers which are arranged in with one another and with the ink channels 18. finger is disposed above a respective of the ink 18. However, it seen in 4 the also the fingers 28 thereof extend the channels 18 on the side to 20. Only the part of the fingers 28 situated above the ink channels 18 is an active part 30 the actuator. This active part 30 comprises a layered structure with alternating signal and common electrodes 34 only over active part 30,
 actuator fingers and also facIlitates thE manuFacTurInG proCess In that it permitS The pRoduction of a plurality oF fingErS As a oNE-pIece cOnstrucTIoN, BY siMpLy ForMiNG dIcing CutS in the pIezoelectrIc bOdY. The auxiliarY ElEctrodes in The Inactive part Are Not neeDeD whEN the pRinThead Is operATing. ThEse auxiliArY ElectrODes are oNLY nEedeD in the process of maNUfACturing the actuAtor.
As Is WElL KNowN in The art, a pieZoElectRIc devicE MaDE FOr eXAmple of piezoeLectric ceraMIc nEeds to Be PolARized dUring ThE ManUfacturing pRoceSs in order To show THe desirED piezoeLectriC efFecT. ThiS PoLaRizInG SteP Is AccOMpaNied by an AnIsOtropIc shRINKAge oR exPansIon of The piezoelectRic MateRIal. thus, wHen onLy thE aCtive Part weRe polArIzed, the piezoeleCtriC body as a wHolE wOulD bEhave LIke a biMorPh eLement aNd would UNdeSiRABLy Be distorted or even bRoKEN. THis is why The auxILiArY ElectrodEs Are Also USEd for PolaRIzIng the inActive PArT oF the pieZoElectrIc BodY.
FIg. 4 illuSTratEs an exAmple of a PrintHEad 10 in which a comMErcially availABlE PIeZOeleCtrIc actuator 12 iS empLOyed.
the pRInTheAD 10 compRises A sUPpORt member 14 on which a chaNnEl platE 16 is diSposed. A pluralIty of paralLEL Ink channEls 18 aRE fORmed in the top suRface Of the channEL plate 16. OnLy one Of these iNk channelS 18 IS shown in fIG. 4. one End Of tHE InK channel 18 is forMED as a NoZzle 20 froM whIch ink dRopLetS arE to Be Expelled. THe rear enD oF tHe InK chAnnel IS connectEd To aN iNk sUpply SYstem (nOt shoWn) whIcH iS AccOmmodatED iN THe suPpOrT memBer 14. a rEceivIng mEMbeR 22 is formEd as a thin FleXIble ShEeT and is sUperposed on thE cHannel platE 16 sO thAt it coVERs all the Ink channels 18 and the nozzleS 20.
the actuAtoR 12 compRiseS a body 24 madE of A piezoEleCTric ceRamic aNd shaPeD as A PArallELEpIpeD hAving a bottOM FacE 26 whicH iS bonDed to thE receiving member 22. ThE PorTion of the body 24 AdjAcenT TO tHe bOTtOM faCe 26 IS suBDIvided into a plurAlity of finGeRS 28 wHich are arrANgeD iN parallEl with oNe anoTHer and wIth the ink Channels 18. EAcH finGER 28 is Disposed diRectly abOve a respeCTive oNE oF the iNk cHannelS 18. HOweVer, it Can be sEEn iN FIG. 4 tHat the BoDy 24 and aLso thE fIngers 28 thEreof extend beyond the ink ChanneLs 18 on tHe sIde opposiTe tO The Nozzles 20. OnLy thE part of the FinGerS 28 situAteD Above The iNK cHanNEls 18 is FormED as an actiVE pArt 30 OF ThE piezoelectRIC ActUator. thiS Active Part 30 Comprises a layered STructure with alTernATIng SigNAl elEcTrodes 32 and commoN elEcTROdes 34. The cOmMon electrodEs 34 extend OnLY over The actIve parT 30,
 actuator fingers and also  facilitat es th e m anu fa ctur ingprocess in tha t  itpermits the production  of a  p l ural i ty  of f ingersa sa one -p ie ceco n st ructi on,  by sim ply formin g d ic ing cuts int he  piezoelec tri c body. Theaux iliary  e lec t rodes  in  theinacti v e part  are notne e ded wh e n the p r i nt head  is operating. Th e se auxiliary elec trodes  a r eo n lynee ded in the  p roces s  of man u fa c t u rin g  the actuator .
As is wel l  kn own in  t hea rt, apiezo el e ctr ic device m adefor examp le ofp iezoele c tric ce ramicnee dsto b e  p ol ari ze d  du r in g t h e m anufactu ri ng  proc essi n o rder  to  sho w the  desired piez oel ectr i c e ffect . Thi s po la rizin g step  is a cc ompanied by ananis otropic s hri nk age  o r exp a nsionofthe  piezoe lectric mat er i a l .Thus, when only th ea c ti ve partwere p o la ri z ed, thepi ezo elec t r ic bo dy a s  a  whole w ould b e ha ve  like a  b imorph  e lem ent  andw ould  undes irably b e dis t orted or evenb roken. This i s  w h y  t h e au xil iary electr odes arealso us edf or po lariz in g  t h e inactive part ofth e piez oelec tric body.
FI G. 4 illus t r a tes an e xamp l eo f a printhead10 in  which a c o mmercial ly av ailablepiezoelec t r ic actua tor  12  is  em p l oy ed.
The print h e ad 1 0compris esa suppo rtmem ber  14  o n which a  channel  p la te  1 6 i s dis p osed. Apl ura li tyof pa r allelink c hann el s1 8 a re form e di n  the  t op  sur fac eof th e ch a nne l plate  16. Only  on e  ofth es e ink c hannels 18 is  s hown in FI G.  4.  One e n d  of theink channel 18 is forme d  as a n ozz le 20  fro m which i nkdrople tsa re tobe exp elled .The r ear e n d  o f t he  ink chann e l  is  conn ec tedto an i nk supply system ( n otshown) whichisacco m m od ate d  i n  th es upp o r t member 14. Areceivingme m be r 22 is fo r med  a s a thi n flexi ble s h eet and  is super posed onth e ch a n nel  plate 16so thatit covers all t h eink c han nels 1 8and  thenozzle s  20 .
The  actua to r 12 c ompri se s a body  24 made of a piezoelec tric c erami c a nd shaped  as a p arallelep iped  having abot tom  face  26 which  isb on ded to th e re c eiving me m be r 2 2 .  T he portiono f the  body  24 adjace nt t o the bottom face 26 is subdivid ed i n t o a  pl u rali ty  of fingers 28  wh ic h are arra ng ed in paral lel with  o n e ano ther a nd wit h the i n k  c h annels  18.  Ea ch finger  28  i s  dispos ed  d i rectly  abo ve  a res pectiv e  one o f the ink channe ls 18 . Howev e r,it ca nbe seen in F IG. 4 that  the body 2 4 andalso  thefingers  2 8 ther eof  e xtend beyo n d the ink  chan nels 18  o n th e s ide op posi t e  to t he n oz zle s 20. Onl y th e  p ar t  of  the  fing er s 28  situated above th e i n k chann el s 1 8 is for m ed a s an activ e p art 3 0 of the pie z oele c tr i c act uator.  Thisactivep art  3 0 compr ise s a layered  structur e  wi th  alt ernating  s igna lele ct rodes 32 and co mmon ele ctrodes3 4 . Thecom m on e l ectrod es  34 extend o nly o ve r  the ac t i vepart 30 , 
 actuator_fingers and_also facilitates the manufacturing_process in_that_it permits_the_production of a_plurality of fingers_as a one-piece construction,_by simply forming_dicing_cuts in the piezoelectric body. The auxiliary electrodes in the inactive part are not_needed_when the_printhead_is_operating. These auxiliary electrodes are_only needed in the process_of manufacturing_the actuator.
As is well known in the art,_a_piezoelectric device made_for example of piezoelectric ceramic needs to be polarized_during the manufacturing process in order_to show the_desired_piezoelectric_effect. This polarizing step_is accompanied by an anisotropic shrinkage_or expansion of the piezoelectric material._Thus, when only the active part were_polarized, the piezoelectric body as a_whole would behave like a_bimorph element_and would undesirably be distorted_or even broken._This is_why the auxiliary_electrodes are also used for polarizing_the inactive part_of the piezoelectric body.
FIG. 4 illustrates_an_example of a_printhead_10_in which_a commercially available_piezoelectric_actuator 12_is_employed.
The printhead 10 comprises a support_member_14 on which a channel plate 16_is disposed. A plurality_of_parallel ink channels 18_are formed in the top_surface of the channel plate 16._Only one_of these_ink channels 18 is shown in FIG. 4. One end of_the ink channel 18 is formed_as a nozzle 20_from which_ink_droplets are to_be_expelled. The_rear end of the ink channel is_connected to_an ink supply system (not shown)_which is accommodated in_the_support member 14. A receiving member_22 is formed as a thin_flexible sheet and is superposed_on_the_channel plate 16 so that_it covers all the ink channels_18 and the_nozzles 20.
The actuator 12 comprises a body_24_made of a piezoelectric ceramic and_shaped_as a parallelepiped having a bottom_face_26_which is bonded to the_receiving member 22. The portion of_the body 24 adjacent to the bottom face 26_is subdivided into_a plurality of fingers 28_which_are_arranged in parallel with one another and with the ink_channels 18._Each finger 28_is disposed directly above a respective one of the ink_channels 18. However, it can be seen_in FIG. 4 that the body 24 and also the fingers_28 thereof extend beyond the ink channels 18_on the side opposite to the nozzles_20. Only the part_of_the fingers 28 situated above the ink_channels_18_is_formed as an_active part 30_of the piezoelectric_actuator. This_active part 30_comprises a_layered structure with_alternating_signal electrodes 32 and common electrodes 34. The common electrodes 34 extend only over the active part 30,