FLUID CHAMBER

ffTOif Some pr¾tmg systems may be endowed with ^' devices for dstsrmming

& level o a 0* ^η & such as ink, av a reservoir o othe i¾idie cham e, for example:, pd¾ may be m%d to or efract ligki beams in ink cartridges lo generate deetms&f arsdor trsgr- e afefe ifc level mieatra , Some systems, m&y; us

¼ckpr^s§ie indicatos to delratue ink leels in. a reservoir, Ciller prating systems may count the namber of iA to s ejected from fakjei pnni cartridges m a w:ay of etermimsg wk. levels.. Still otfeer s siojmmay use ttie electrical conduc e of fte wk m wx ink level Indic tor in pm&mg system^ m Emmm M jM&m mm.

0§2 Tte detailed dejsfcrynioa secsios: refereaees rise ttaswng*. erein;

figtire I is a bieck diagram of ^' m e ampl of a

suitable for iirorp ^ ¾:¾« head-¾tegrat¾t se sors;

Figure 2 is a persp ctive vie of as exarsip-te t d ejection catidge suitable for «TOfp r8 ag->r to^iftt€gfatfd s jiMs;

Figure 3 is a bottom view of a pf¾ ead mclydisg a fluid feed slot aad 8ihe - «tttisd. mk level sensors ( !LS!;

Figsre 4 is a 'eoss*seeiio«al iew of m example flaid drop tmtor

Figure 5

t 30 Fsg s 6 iS.aaotte-sf0§$~«iiaasJ vlsj of th& example ense simcftsre .of Figaro?;

Fig we? is & iiromg diagram of ises»-i¥f rig t g eloefc si isfe tised to drive & py^il^

i ue 8 is s» example ihk level seosor circuit;

Fj »re 9 is a cros^mf at view &fm ^ ph m ® txm with belli is feme eapeter mi. i nmk- pmrn eapeitt te ;

Figure :M> s a emss-sestonsl ie of an exam le $ΐ« ¾ ¾ ^' thai.

Figure 11 is example MI mk leve sensor mmk imMdrng a parasiile dis& stiim circuit a e!eadag resktar dwcml, id sbiil legi te *

Figure 12 is w exam le of a shift register t ai addresses a piamlity pf i'U. s¾«als; ax-d

Figures 13-21 illustrate vm½«$ stages of methods fer uiaidujj a setrse structure, of aPiLS;

ail in wfeidt sj as embodjaettts may be iai kmented ¾^f ^' are sho tt li ihe drawtegi and descri ed in detail below; ^' The draw!ujp are Hot jsa©8$s¾% to sca , and various features and views of the ■dr ings may be sfcowti esaggetai d m seafe or m sc¾e;umtic tm eiw&y. a»d r £Ou se»s. The saase pan uumuet ma desiguate the same or smilar pasts t r iiglsoisi th drawings. IIQM

1¾si¾ are a mrabe. of teeMques- availa le for deteraijtnkg a »par¾? ef$ fluid, m t k., in a reservoir o other fUwdfc chamber..Accurate ink- level >s g m i»k mppfy reservoirs fo nm y types ®fmk$ pm , fw fosaaee, may be urable for a mimber of r«ast¾¾. F r ex m le sesskg the cotrect lew! ofmk md povUmg a coii¾s oradlaig ^oskm of riss m v i offak-M m m mk cartridge allows primer «¾s to prepare tx> replace finished ink cartridges. Aeetrraie ink level iadicatiens also help i« a void was ng ink, since maccwate kfc-leyd k&atiom oifes result la as premature replcement of mk egfiid ^ taat still contain mk. In a diti n,, rinting systems can tise Ink level sensing i& trigger certatss aciiom iba. hel event low quality prists that « ht h tern in&decj ale sup levels,

| WS| Described herein re various iai taen km of peaiiead-mtegrated sensets and pising tee¾.Mques _> .a»d apparainses ar^ systems endo ed with ch mwm and/o sensing teelmspes la which a gmm electrode for the sei or(s) Is exposes! Is) t.he Mid chamber for directly eentaeliag. a Mid m she Hutd _. chmber various Ij¾pi5«esiiai50ps _s dm sensos m mm a property Ce,g.. _s . Mid■ le e, is^e tute, of tfeSk aid, my be. integrated o.^i>oard a thermal mk i (III) prktbead die. For example,, the sens rs t y comprise ii bead- tegrafcd ink level sensors £P!LS), in t of the im lement tions, the sense circuit may iM Jetneni a sample aad hold tectoiio thai captures the ink level slate of ^' dse fl i ejectloa device through a eapseitive sensor. The c¾p¾ci«e of the eapadrive seasor «¾¾y change with, the level of nk for each MLS, a e!mi placed cm the eap&ciiive sens r aty be shared between d^ eapadttve sessor and. a teforeac capacitor, cmjstag a &etsee &N&ge a* the gate of a« e¾al«¾ii<m irsfistsia . A ewreii sowce in printer a plication, specific Integrated etraat (ASIC) may suppl ewrmtiai ike

ASIC am the f»{tag v ha ^; a ti epcrenl source m4 cale»f¾t« Ae caf esposdiiig daM^o-soyrct resistMiee f e l^aiioti transistor. e ASIC .may i m d termin the mk level states ©fibs fl« αΐοη devic based on t e esistance determine -f tii tte t valijaioft taMtsrar,

fiKWMf Ιίΐ ariou impl itataii«, dt gwmRd eteetf e exposed to t & fluid chamber way provide a grajsml Ibr the se¾e .circuit The gr*m«d electrode tmy saclBde a fet ffieta layer exposed 1o te fl«M c¾8«ijer through a via in the

ssl atros layer, a»d a secon metal layer o? the fmi mete! layer-ami eeeiiected io an ps-di gound path, is vadotts mpkraeaiaikros _s the pas atroil layer Pttiy shield i e s con metal layer fron¾ lie il ad c am er,;

filMTf hi ysm&m im m i . accuracy may fee im roved thr ttgh the m of rriufppfe P!LS i egiaied on ¾ prinfead die. For e ampi a Sad ejee cm d¾Vtee may i kids a ftm MLS to $m$&m iak le el of a first Btdd chamber ½ fluid spaaiiuatc¾t80« with h fluid feed slot a second PILS to sesise an iat¼vel of a second fluid dmmbssr *» floid commuatcatiett wiih t e fluid .feed slo, A shift register may seve as a selective dreait to address the mathple PILS -and eatable the ASIC to m $W€ awltiple hages -and tleiermtae she ink level smtm based on m mm nm ia¾ e« at vaious l cato s p& die tMhead die., ha va oiei im lerfieatadiins, a iMd chamber 1» lad coffi¾unieaifM with a lluid .feed slot of th fluid ejsvtion device ay iaclade a clearing resistor circuit to clear dipfhaid chamber of ihk, §#Μ*8| 1» varies® {mpte erviSiijns, a prtscessof-ffiaiabfe raeiwa may w®U code f«p.?w¾atf»i that hen executed by a rocessor eaase the processo to imiim c^er hw of a ¾¾ί pti«{-h.e«i-kt«gwed ink level sensor (FILS) of a isi md ck i>& m ¾id e mffi ieat a with a fluid feed slot of the fiaki ejector* de ce and a second. FILS f a second italdchairiber ¾ H d c»airaaak iers ¾ u ihs? fluid fed slot, A shift register may e car lle to maltJpiex p $ .ftota i fmt MLS mi the mmd MLS «>$«» » ^· « «ϊ«¾ « 10 Iw< Frma ibe outp*n$, m mk level stale of Ae flad ejection device may e deierrtused ased o diluting ink levels sensed fry theifet MLS a¾d ^' the seeosd HLS.

fiKM> I vmt impl it&im a pfece«or--eadabIe ediam-may store code repre^nisg m¾tmctio»s ttel when executed, by a aiessefr m the pocesor to acivate a dearmg mktw mmh tq _. purge Iran a i½id cteaber, apply a pre- charge voltage Vp to a sense capacitor withsBitoe fluid chamber to charge t e sense capacitor with a c arge Qi . I¼ charge Ql tmy be shared ¼t e ¾: ie sejrc capacitor and a rderesee cs aekon earni gs reference wltage Vg at the gate of ars eva ailra imsjssiox. A resistance may: be (tetettntaed from .drain to soiee , f t e «ya!«ap©« imnsi iit. Ih es lts item Vg, to m t pi mk _f ¾ deay m be povided afte seitvatiig th clearing resistor ctrcait to eaabte mk loss a fkdd slot to flow ack mia t e laid chamber pnor *ø. applying flic pte-eterge voltage Vp, f#Mtf T«t»i«g tmw m Figre I, iliastfased. is a fcfeek diagram of an example

.fluid sjeeti ii system: H¾> sttrable !¾r ineorporatjag a ftatd ejectiijij device cara ri k riuhead-kfCfmtei se s as. dsciaaed fereis 1» pari us itftpi.e«%ett!atfe«s, the H»iit «J-ectkr ¾te 100 ma ee-ai se aa iakiet iraer or ris ng systet The IM election i 00 may include ¾ prtarlead asembly 102, a J¾d su ly assembly

ICML a ffiojMl¾ assembl 106., a media transport assembly 1 8, ¾rs electorate e«s¾i roller 1 Hi d at l-as oae power s apply 112 that ma provide power to the various eleetrieal eompoMrrti; of !½kt yj dtorr system !00.

Ttteprui&ead. assem y 102 ma Include M least m pnnih d 11.4, The ρπρώ¾ί¾ΐ| .14 may compris a rbtlhead de ¼vrog a fktU f d. slos akmg: a I g II . f a prmthead wt® si i a Oidd, k m ¾ f exarrspk pkmUt mx § I K>> Th# plurality «f wsfe 116 i eject ejects drops of the -fluid toward s priM media 118 so as to psi«t otsio ibe priai me ia 1 IS, The pout ®$ 11 mm be my t pe ®f sutable sheet or li material sad* as, t exam e, pape, eid stock, l.ra»sparertcfe _» polyester, ply ood, loam board, fabric, ©a&vss,. and the like. The mrnks 1 6 tmy be arran ed ia ne or r«re eohrmrss or arrays, ®&&h thai properly $eq««8se election of .fluid from ts iades 116 ma cause efmraete. sym ols, m&m other graphics or images to fee prmted oa i prist media I I as ie prittthead assembly 102 aad print «¾edis I I are moed elati e m each other,

00t2| Tie fluid supply assembly 104 ma s litiid t die prlssdtead assembl 102 arid may taeksfe a .res&mnr 1 0.fer t ing the fluid la enea, IMId may l!ow fmm ie reserve!? 120 to the prddhead assem l 102, aad the faid supply »et$bl> ^< 104 arid tie {Kffflhead assem 1 2 may imm a orer f¾ deliver yst m or a fecrreulatmg iimd deli ey system. I« a two- a Buid deliver s stem, sAsiamlal!y all As ikid sup lied to e pnatbead assembly 102 may e (M«d dartog prk«Imy &rsdrerdating fluid delivery system, towever, only a otiiM of dr Ikid supplied to lie pnrttod assembl 02 may be eoBssmed w sg. prht g. Fluid Ot ons med during priting ma be m¾a¾ed ie> ib fluid supply assembly i 04, l¾ te¾er¾¾ir 1:20 of ie fluid supply assem ly 104 may be .remove _* replaced,, aad/ r refilled

W3J The :mmmi» assembly IM> amy _. notion Vtw ptkA i assembly I OS fgisti to the wnedta transport assembly 1 8,. an the meda transport assembl 1 ¾ tm pmil n rise print me ia.3 IS elative to the priothesd assembly I Q, to. ibis cmfi mboL a m mm 124 ma be defined Ja«Mt to the .no^te 11$ in m mm between die rinthesd assembl !l>2 md pmt media IW. sovm mplementator tb ^' pdm d assembly UM is■ a scanning type -print ead ss mbly. As suck Ibe mowti8§ assem ly 106 ma cude a cariage lor moving the priMhea assembly W2 elative to the mdia transport assembly 1» scan the print media 1 IS, In oiber

asembl . As uch, (fee moriiidrri assembly 106 may _. Ox the prindiead assem l 102 si a p seibe osii n isist- e so the media tmr¾ rri assembly 101, Thus, the me ia tmmpot assembly I OS may o lderi the print media 118 relative £$ the ptiaibead aas asbl ICS,

100141 ¾ lectronic ¾of*tmlier 110 ma feektde a procssor (CPU) ! ¾ memor 1.40, firmwre, software,, and other el ctises for cotnmunk»&iag mt mid controling rite pitmtheail assembl 1 2, euntasg ass-etnbly 106, and media ttampra msettshl MM., etnary 140 a tektfe teb volatile (e.g. _; RAM) and nonvolatle (e,g, _s ROM, Iwi disk, floppy disk, CO-RO , -etc.) .ttimory compm m camprisssg

e^m uf r^!reeesser-ex e rabl ceded snstmet m _* data streetures, prftgs$«¾ modafes. ¾l other l¾la for tbe pra¾¼g s stem UUk Tie e!eeitmae c roiisr 11 .may we v data 3tt fiam a ost s stem, swell as a ©eaipuier,, aad temporarily store the date ! 3 m vmmmy Ϊ , Typically _s . the ^' daia .130 may be seat t the pr¾tmg sysem 100 al$ag an eU¾tf$nk, i»i¾tr«4» o tica r oiter iiiiaaiatioa transfer Uii. Tbe tJato I ) t y represen for exam le _* a document atid/or file to be printed. As sk, the dsla 110 form a prim job f r the prhttmg system I. W aod m y include one m m re nt ob comman s &m eosaratsid pra eers.

|< >ί 5 I» wbtis im l roea talfe s, he electronic eo b ^' oiler I i may control the pristliead assembly 103. ibr ejeetba of tesd drops. ! 17 tmm the m ®* Ϊ 16, Thus, tbe eteciratie controller 110 -may define a patern of Reeled fluid do s ! 17 that tern characto, sym ols, am!or othe graphics or irts ®®. rhe prist -m®$® 11 The pattern of ejected iM44m& i 17 ma be daseOTaeil b tbe pr&t jols cotamajids md©r€©03.?»8»d parameters from the data I W<

ftK* M Im v m i lmtmWimi the electronic coatrpller I ! 0 may ioclisde priaier app!icat a .specific Integrated: circuit (ASIC) ^' 1.26 to deterffito 8t least one proper (e,g. ₅ a fluid level tes3¾ erats» , etc.) el ink in the fluid ejeedoa

de kei nsitbead 1.14,. For impiemeM tor m ich at least some of th se¾s»rs 122 comprise FiLS, the ASIC 126 may determine a ilu level ofco r^ oadia fluid e arabers bas d o¾ resistaa e v te ton «e or more .HLS. Tbe pfister ASIC 126 a feelasj a ea¾ ¾ome ΊΙΜί aad&a aaaiog^o-dlgit eowerter (ADC) Ϊ32. Tbe ASIC 126 rim covert the vsJtaj m i M earrejrt soiire Bfl m detetmke a tesistaisce, and i m S ermm cors-apoading diitoi sBrasee value though the ADC 132, programmable lgorihm Implemened through securaMe kstrocdoss toodt s 1.28-1» mema 140 tmy esaoieite esjssaee ifeie«¾Mi io» and the $u¾sa$ue«i digtal co8∞k>» thmsgfe the ADC 32. In vanoas imp ^j emampom, t « memory 1 0 of ¾iecir «ic cannier 110 may ¾d» e a i k dealing module ! 34 ih&i comprises iosirucdoiis execuable fay i¾e processor 1 of fte ixmftet ! 1 so activate: ¾ clearing resistor ek¾ttit o» the imegr ied ptkftetd J 14 to i ink dfm - m ml ί a PUS fluid cham er, in another

fffi l mesPMioo, ere the raihsad 114 comprises ^' multiple ΡΙ1¾ the wmw 1 :©f the :ig!ectt«¾i- controller 110 ma itclode a ^: pograms Ale . g ithm iraptenieaied to gh executable ½&nict &s ilten a P1LS seta module 136 executabl is tie pocesso ? of the OTtr ller 330 to txMi&X a sfeil wgise |¾r seteeiog idividual I¾tS to e used t sense ak levels to dsieri«i»« as iak level state of the uM ejection d«:v½e..

| OJ:7| ls¾ w ffi iM iem oiaibas, toe grimng system 100 is a .drofKia- deom d temal kkje prhtilsag system wit a i¾er«¾¾l «jkfs-ΐ 01 J) prmihsad 11:4 suitable for impieaienti«g a -jiitlm d die 114 lavbg a h liiy of s ns fs 122 and groutki electrodes for the season? 122,. as escribed krek i»¾ome i^leaaaetet m, fee prlothead asembly 02 may kelude.s single TO rkthead 114, la oQtm

iffip me¾Mi08S 5¾e pi1«thead assem ly 1:02 may aseltide $. wide array of T13 pdntheads 114. fttte tie iabrkaPon rocesses associated th TO prto eads are well s iled to the -egr fea of die rmt s dies described terem> other prt8tl*e¾d types $m m a pie mlectrie priridieaii $m also itnpfemeat a prlriihea tie ί 14 h¾vl¾g a ptasisi ofsessors 122 and- associated groirtd electrodes. !§0:ϊ&! ¾ssej«?Iy 102, fluid su ply sembl 04 _> 8»d reservoir ISO may be ho s d, together is a replacea le device saefe as m iategr¾ed pciaftead earSrsd ;. F%«re 2 i a j^rs eetf e vie: ef m example Inkjet cartridge 20§ t at iaetade tlie pisifhead »e.mhly 1 2,. ink seppiy assembly 104, aid

|0§l*>J la addii n to me or :mc*w fsriatfeeads 11-4, rakjet cartridge 200 m&y imkidt electrical c »l ci$ 205 and &tt ink (o:r «th¾f fluid) supply chamber 202, ½ sctroe ¾raplOTe« 3onS the cartrid e 20 may ha s a sepply ehamfeer 2d? thai stores oise cote of ink, ami m other s¾ !e:me istisas it may ¾avs* a. aa taber of ebarnben? 207 thai each store a different color of ink. Tfee electrical contcts 205 may carry electrical signals to aad from a co olJe (such. as _; , ej the eloetrica! controller I 0 desalted herek th refeenee to- Fig e ) m& power (from tie power seppy ! ! 2 descri ed berea wills r«f«re«ce to I? ¾r 1} to cause the efecrioaof Isk drops through the i¾ ¾ite 216 md tasks i&k level m m mnis-

^' {00201 Figure 3 show s a _. bottom view of m a k- Im^mm M n of a Til rmthesd 11.4 tuktdieg seusos 122 c Bspising MLS (heieirafier "MLS 1.22).

Fi aro 4, , and 0 ste various sct ns! e s of the X!J dMbead ! .14 as IrssJkated by lasbed: lines 4-4, 5-5 _* mud 6-6, respectively. As shown, tbe-prkihead ! 14 may laeltide. a fitsM feed slot 342 ftraed m a $iiic _. » die/substrate 344. m aecofdaa e ih arious m feffiei asiMs, Various eoritpoaeBB ¼tegratgd on the r tbead

die/substrate 344 mny In lud t d dro getteators 346, a paraity of ILS 1.22 a d related circuitry , mad a shift rgiser 3 8 coupled to. each HL 122 suable mutiplexed seecton ofiadradaal PILS 1 2, as discussed ¼ _. greater detail el . Although die prhitiead lU is shows* wii a si«gk fluid Hold slot 342, fe princi les discussed herela am mi limited- m t eir pl %& i& a pdnihsad with just one slot 342. Raft r other prfehead es«%»iad m may also be ssi s, sueh as priutrseads wih o -or mom .fluid fed slots. In the TU prfeije&d 1 £4 _÷ ifee di/stfei« 344 nnderltes a chamber layer having fluid efeaibers 33*3 and a nozde layer ?wviu¾ t ¾ie$ ! Id formed t w, m discussed below with respect to figures 4 and For the purpose of ilfeimtiosx however, lbs chambe layer and tmwte layer in Pimm 3 is assumed to ¼ transparent in order t show tlw md ymg m^ t i^ 344, The fluid cfcambors 5i: therefore, are illustrated usiag dashed lnes is f igure 3,

P>2i I lie fluid feed slot 342 may b an ebogated sbi tmrnd in the sihstnde 344, lie flnid feed slot 342 ma be in ^' flnid ecawmfecatioti with a Ikk! pply (not s owii), sash a fluid resevoir 120 shown Figure 1 , The fluid fed slot 342 may include i¾td ^: li ie fluid drop wral rs 346 'arranged afeg bosh si«k$ of the Said fed slot 342, as well as a plurality of PILS 122. Each of the PILS 1 may l3€i» ^' .il»M-co»¾¾«8ieaiio8 with die ffia fed slot 342 and may las; eoftflgared to sense aa wk: le !, of its res eefee fluid ehaafer 350, as described mru¾ fully iierelis. in various Imp nMnt ifes, the PILS 1 2 may he toc ed. generally toward ihe fluid, fed slot 342 en s as-sho n, al ng either side of the fluid feed slot 3 . For example, in. m im ! oieu loBS, a fluid ejection device may Uictede lour PILS 22 e I d fed slot 342, each PILS 1 located ien rally near one of fowr eortsers of the Said, fed slot 342 _s toward the ends, of the fluid fed slot 342. la other im ieTO niadoits, a fluid e]eelio» device utsy imkA i»¾ than lour PILS 1 2 er i¼kl fed dot 342,. at least oae FILS 122 locaed geneally «.e¾r ne of fer corners, of the flak fed slot

ii/30

i 14 keh«te four F!LS 122 per fluid feed slot 342, with erne MLS 122 located generally near am of the few comers .of the Ckjjd feed slot 2, toward te e«ifs of the ilidd feed slot 3 ,

? presem' disclosue,

IWZ2\ While each FILS 122 is typically located n m m^ m of it® fluid feed slot 342, assho i* »t Figure- 3, tis is txm. i mkd a Kmlmiort n other possihfe locations .«f a PILS 12.2. Thus*, f ftS 02 oao fee l cated mmmd the fteid ^' fed slot 342 m mk&r mm mck m mdwa eweers the esds of the ύηϊά feed slot X> m s FILS 122 mm be l ocated m ooe mi of tie f -d feed slot 342 suc ttat.i esteods outward from the end of tit© laid feed slot 342 rafter than, flora die side edge of the fta! feed slot 341

MLS 122 located generally sear end-comers of a Hold feed slot 342, it rosy be :sd:vioiage ¾iS to aiaimai a eemk safe -distmce between the plate sense eapacltor (CsgBse) 332 of tfee FILS 122 (e.g., et w* « edge of the ptafe sense ea etor 352) mi t mi of tlie fluid feed sio 341. amtaMuf. a mmiaittm safe distance tm p to etmm that t e is no signal de radation tao the sense sa s r (Csesse 352 dae to the poieodai of r®d«c«d iWd flow rate hat amy be encounteed at the emts of the ftdd feed slots 3411» some im i^irttailo ,, a itti«ra» safe dispose to amitiiai .be-t.wss8 tie plate sem cspac dor (C ense) 352 aad tie end of the 8mi f ed slot 342 «jay.be ai tei 40 μη\ mi m mt i ^ & im , m feast about SO p , ft23| T»mi«g now to Figofes 4, 3, a»d (i, with mt l x &

Fi«oo¾s 1 -3, IMosirated ate secd tial views of ihe TIJ p«ot ead 114 takers, along

n / 30 !ί¾8¾α! Kt 4- _s 5-5, a» M. TO eei¥«ly; _: As $h m in igure 4, rbe <* gett.m«r 3 ¾ amy mdude a mztte I a fluid cham er 35<b and. a t M pirn 54 ifeat forms a firing de eit <&§ki$ed in the fluid ebaffiber 35 _* The ueirfes 1.1£my be firmed m a ne«*ie laye .3 ami am gaseraliy arran e , to- torn m*;2te-mlym&$≠m$ u¾a sides ©fibs- fluid feed slot 32. Tlie firing element 354 mm be a thermal resistor formed, of a dtssl mi layer meta! plm (e.§„ al¾m«« s -€o:p:p¾r (AJCu), isatahim- al«p»«m (TaAJ), A!Cw n. TaAJ, at A1C» on tiingsitm sHfco« .i»trid& (WSiN¾ ca iasiSsHiig laye 35 (e,g., _: pbosphoallieare te (PSO tsideped silicate glass ^' (080),. teoptepteilkaie glass (SPSG), or a eoaMaad a thereof) «ma top surfac of rbe sliic©tt substrate 344. A passi aikr layer 36fj over the i ng e!emeai S4 may otect ie firing e!ersertt 334 £roro½k o the fluid clabbe 350 and may acl as a meebamea! ipassiv t rii or protective csvitatSsott barrier structue m absorb the shock of icoiapsartg vapor babbles,. A chamber layer 362 may !»¾ wails aad fluid chambers.35 that s arae the substrate 358 f aa ite &uM layer 356.

10021 During eati n a ifcid imp may be ^ ^' eeied fmm a fluid chamber

330 thmugii a eeifespo tin mute 116 d the fluid h irn 350my be refilled with fluid€ire«¾t¾ from fluid feed: slot 351. fe spcifleaUy,.M electric ma&st ma be passed through a resistor flri»g element 354 FssuMiag in rapid heating o the element A thin ^' layer af fluid adjacea to the issi loii layer 360 o er the Si¾ dmeit 354 umy be s pefteated aad vapori¾sd, creaikg a vapor babble iM cff es o isg f rbsg fluid .chamber 3¾. The mpidly .s ading vapor babble raay e a fluid drop mia die ewes otidisag inca& I 16, When the teii«g eleraerii cools, ih ^' « vsrppr a le may quickly collapse, dfawit%.mor fluid from flaid feed slot 342 into lis? firing ίΐβίί! c:ht rater 35 in prep ation fox jeedag another dro Ix&m the ste¾S i 10

^' {MtS fig red is a s ttenal ve of a nrdon of a« ex mple sesse sfTuSMer

3#4 of a P!LS 1:3.2,, m c ^mm mth mm implm uiim$.> $Mwn m Figure 3, t e I ^S ILS 122 generally may iaslads ifie sense simciwe 364, sm r dretuUy ¾t\ and. a cleaing ftsistor circuit M imsgtm mi i® tmmd 334, The sense rocwe 364 of the PILS 133 may foe gen miy wftgwred ra the mm m z *& a do

iw ifce %mm pm (Crease) 352. tough d» slance (e,g., wk, irtk^ir, i) In tie ! ⁵ ILS ftoid cham er 350. Tberefwe, life a typical drop generator 356, the se¾se jf» fe 364 ¾d ufe a ¾o¾¾fe Ί 1 a ftwM cfcamfe&r 3,50, a co:od«etiv¾ element w&h as a metis! plate 355 disposed t m toe ilutd¾k charoter 350, a passivaiien layer 360 over t e meal plate 353 _s and m kmim g layer 356 ©,¾„, pdyslMeon glass, P8G) on a top surface, of the $»lw mbsiz - 344. Ifowg-ver, as diseae above with rei resee m Figure 1 , a PILS 122 may additaaJty employ a mnt Source 130 md analog to dlgdal convenor (ADC) 132 H rn a pt ter ASIC 126 thai tm feKegrated &a priathead 11 . nsead, he prisfer ASIC 1.26.may fee k¾ased _< for exam e, on the printer carnage or electronic conroler 1.1.0 of tire prniier system ^■ ICMJ. f0026| Within, the sense stricture 364, a sens eap citor 35:2 mm lie formed by the arta! plate 355, the pasxi layer 360 _;i .a tte ¾b$t £e or coue S efthe.fMd chamber 350. The seasfcr dieuirv 366 M iuex>rpor¾te sense ea aeiior (€¾eme) 352 ^' faym within dm sepse structure 35:2, Tte v lue of he: sem cs aew 35:2 may cha e as the atfo ii e wsiiiia the fluid amber 350 ektages> The suosusftee in the -fluid cha ber 3.5 gatt e alt ink, inkarid slf, « as$ air. Ttes, ihe value oftffcg s¾se ca acHoir 352 eh&uges w ls the level, if lisk m tfee flu d?8»¾ber 3 SO. Wlwrrink is present ift the fluid c amber 350, the sense «a .ctl r.352 fess.good. o&tKhici&ucs grotuid.37 § th& sapaciianet value is highest (e.g., !00%).> Ho ever, whe« tiwe is n ink in the fluid cham er 350 (e.g. _* ir oa ^' ly) the

capita tiace of sesso cspae!tor 352 d to a v*ty smalt val , - kk is ideally close to ¾eo<. When t e -i¾id dumbe eoru¾Ins ¾k and air, t e cajmc aswe -vslue o f seme capacitor 352 asa bo somewhere beiwem ero a d 100%., t¾i».g &e ^' dian ttg valse of the sense ca cirar 352, the i«k level sensor circuitry 366 j gy enable a detemth loi* · f t e kit level, in general, the ink level in tire Hold chamber 351! may fee iodleative of h ink le el state e:f mk in reservoir 120 csf prioier systeos U)o\

£4027} hi s me at l «eat¾iess, a cleoriog resistor circuit 36$<may bo use t purge ixik & ink residu Droits the .fluid chamber .350 ofhe IHIS sens structure 364 prior to njteaswiaf h tafe level with n t circuit Thereafter, to the ex«. that mk. psesemt is the reservoir 120, it rosy flow hack toe ^' the flttM chamber to enable an. accurate Ink level aieasMso st, As shows* m. Figore 3, i» various .im lemeataiions ^' a el.eari»g resistor ctrcuit 368 m¾y include four d wing resistors surroimdkg the nsetsi pfaie .355 -of the sense ca acito ( seuse 32. Each desdag resistor ma be aojaeertt one of the four sides of the metal plate 355 of the seuse capacitor f.€¾e«$e) 352, The desrbi resistors £¾ ma c mpose t ermal .resistors formed, for e am le, of AlCit, T&Al, or ACw oo TaAl, stich as discussed abo e, that rnay provide rapid eotiog of the mk. to creat vapor hnbtiles that fate iok out of the MLS fluid ehasihet 350, The clearing esistor circuit 3 S m$ patge ink from the thhsj e arofcer 350 s¾it tstove residual iftk from the fo l plate 355 of $ »s capacitor (Csense) 352, I k .fl wiag back, imo the P!LS . «ki c am er :3S fr m .the t¾k ^' f i¾ed sot 32 ftben may soafsfe a m re ee¾r¾is seiss of the hsk toej thrwgh s issseca oior (Cserrse 352. In $ Μ& im teM WtiM . adetty i¾¾y be pro id d by controller 110 alter the aeii vstion of the clearing resisior ci rcuit 36S to rovide time for mk fron iliiii J¾edsJot 3-42 to flow b k imo the Pit , ύύ cha htr 351.1 p½r to siim$ 8m ink itvel m Ihf WL \M cte ter 350, While the clearing resisto circak m four resistors snomraulng t e sense capacitor (Csenss) 352 ma ha e art ad: vantage ¾»ί providing for a significant clearing of ink from the sens capacito 352 and fLS fluid elaaaifser 350, other earfag resistor co».%um$iee are als eontemplated that roay provide clearing of ink to lesser or eater degree*. For sample, s ciear g _. resisto circuit 3 8 muj he coatp:re4 with as resistor eonllgrrrahori m which the clearing resistors are ra^iiae with. tteanehher adjacent the b k edge of the metal plate 355 of sense capacitor ( esse) 352 at the hack sde of the P!LS fluid chamber 350 away Ixom the J fed slot 342.

|$Φ2$1 As he ts, the gimrad electrode 310 o f the sense sttyeisrsi 36 say foe ex o ed i* the fkki chamber 3 0 through, a via.371 knhe sssivstioS; layer 38), As sho n in Figure t _% the ground eleetrocle 370 may com ri a first metal layer 313 and a $e¾o¾il metal laye 315 on he first metal layer 313, *&e via 3 1 the passivatl i layer 3o0 ex osirsg a poriioo o f the tlrst metal layer 313 to the fluid eha»her 35th The secotscf otemt layer 315 may he eormeet d to oiwfk g«®«r?d h Coo stera) from eleettieayy eoooecthtg the fet metal layer 313 to gr ms . §02θ| Tie grate electrode 3.7*J may faferieaied in a stela roasisser, ?md

Ir Is t some imp! mom ks dariag ^' the same apega&m, as the fixing eimmt 35 anch r the .metal plm 355 of sense capacitor (Cseose) 352., ¾i€lr:may smipKfy, or at feast ,mimmk¾ adddfesal complexity i the eess Stow for fabrfcaisrig the pri»tbss4 As s own, in -Figure 6, ih rowid electrode 370 may comprise a das! tuetat layer $ similar to the iriitg demerit 354, ith me s eoEid m tal layer 375 a Sl d tt!ge resi ¾¾ ik>m a wet eld* ofs r i ia to exp se Ao imderlying first metal l ay w 373 , as dieased former deisS! below.

IMWl Although me first mete! kyer 373 md. Shi rn &d teeial layer 375 ma co prise air cotidaetive material swkabte for the a licati n (mdi as, eg,, AlCa, TaAl, WSibL mX m marry impkm m the ektai roetal layer sinKafe of the gwtmi ds r de 370 ma allow lie first :meia! layer 37 t be iabrieatd with a «al tevitrg ssisiti3.ee lo corrodoa by the fluid m the flui «f¾amb«r 351 ⁾ ( .g.., ink) 1!M¾ tie metal of the second metal h 375, wits fee pasivati n layer 6 shielding the md metal layer 375 from. iN ehamoer 330, as s own. Although some ftt kttenttt&M may iwc de a graiad e etrode 370 m feleh the first mmti layer 373 and the second metal layer 37S comprise die sam metal o metal alloy, other ho femermsti BS lo whic the grouad. efccimde 370 comprises two dMY«at metals or sitetai alksys may allow lor greater desigEt fleslbdJiy, hich may to ivm ak for a mt t aciioo by ashtg less exfM¾»siv¾ roeials or metal alloys whea fs <mM&, l¾ a oa,. the overall fabrication of the piBthead m&f he simphfted by rsslag she s me pocess o e «»!y) for fabrieatiog the ouse. electrode 30: as ftose ased for fa neihn the Sristg sk i 354 mtMot the m¾ l. plat© 355 ¾f assise capactor licens ) _. 352,

|$033.| Figure is sa xai¾pte of a ar a ij mg diagxsss 700 h»v¼g mm- ov appissg .cl ck signals (SI - S ) with s¾¾c¾:r awd data ami fie sgn ls: may he «ssd ϊο drive a onlbsad 114 _» its accordance with various im tesft us, The clock ih ais h« timing, .dagra ?00 may be used, to drive the o tr ioo of the MLS k level seosor eheulf 366 aod shS registe 34$ as dkeiissed belo .

|iM>32| Fig re 8 h example mk level seosc circuit 36 of a PILS 122 _> m accordant with varlpys impleoiCiiaiicas, In geneal, the ssssor ekctdi 3> xmy empl y a charge sharing jaeciaaaisnv to deierr¾!;tie t&f&tsoi leves of mk in a FILS fluid cbs fear 330., The sessdr eircm! 360 may include two frst ttsasjstos,. ft (1Π a. Tib), c ns ired as. swtches, eferring Figares 7 8 _: , during operatl s of the server circa 3 m a first step a. clock pake S I is used to t\m® the tranistor switc es T i a and T 11),, eow feg t mty nodes M I ms& M2 to gro nd a«

disehargiog the seas capacitor 352 and the Kifereaee ^' capacitor 80. The mf«m.«e ca acitor 800 snay be thecapaciS iee b een node MI mi gpootsd. In this exasnp!e, the reference eapae or ICMl tay fee impfs∞»ed as the ttteest gafe capii aaca «f evateatioa transistor T4, m4 it i therefore iltostsated «si»g dashed Ikies. The

:rcfeeoce spacjior O taa diuo lfy include associated parasitic eapaeitaoee siicls as ate-soiree overlap eapaeiiaoee, bat she T4.gate capactance h Ac oMioaai ca citasiee in referersce capacitor 800. ^' Using the gate ca aehart e of transist T4 as a fcferesee capacitor 80 re uces the mmiber of eom ©he»ts iti sensor elf cat Mi? hy avo log a s ecific refernce capae ca ^' feferieateiJ et eea awte MI a»d grotrad la

lit / 30 ther to !CT¾sii¾is0«s _; however, it may be eneficial to &dju ^: $i the valoe of reference ea idtor 80 thwg i¾eiac slos¾ of a s ecific ea aeitoj: fab rivaled f m M2 to rnmd (e.g., m sddttieo to tits ¾!iers« gate ca cito.c« of ? ).

CB3J Is a sec s step, f¾e S t cl ck ui mim , o a»i»g the Ti¾ and

Tib switches. Direc after ihe-TI switches opea, an, $2 clock pulse is «se fc etese m or wticl* T2,€te*ing T2 eonptes node M ί to a. o &sr voltage, Vp (ej,_ m B order of -| Svo!fe), a charge Ql is place asess S UM apacitor 352 according to the eqatioi*, Q! (Csenas^CVp). At Ms tiros the- M2 m s-t mmM «ero voltage pote ial saaee the S3 clock pulse is < , In a t id step, the S;2 clock poise terminates,, opeoiog the T2 iratssisfor switch. Directly after the T2 switch opens,, the S3 clock ulse closes traaststor switch Ϊ3, coupling aodes M l and Ml to owe smother arsd sharig the charge Ql etwees seroe capacitor 352 mi referetree capacitor MKX The shared charge Ql between sense. capacitor 352 ar«I

capacitor 800 resttfe to a reference voltage, Vg, at rtole M2 which is also at the gate e:fevaf«&ii.oii transistor T , acmrdmg.to the following ©qast a:

v . Csensg _v

9 \G$erree♦ Graf/ ^

fftft j. Vg rensaios at M2 tm.h! aootfer eye Is ht ius- wife a clock, ρκ m $ I grounding metnoiy nodes Ml and M2, Vg at 2 twos or* evaluation trnsistor T4, which ena les a meMorem Ri at IB 802 (tee dram f Iraiisis T4>, in ilm

erati n where T4 acts as a resistor whose value is proportional to the pie voltage Vg (e.g., refeesee voltage). The Ύ4 resfeiaac from itm to source tcoss lod to gsmmd) s d eg d by mu¾ mmm m 1.0 ml feg, _¥ a current « the $#x of I miUta p). With a itional .refemsce to Figure .i„ 1.0802 is ceupled lo a carre s urce, »h as c»n¾« s oros 13if ¾ printer ASIC 126, l$p ipp ag ihg.c»w« source at ID, he voii g* V|ft>.s.w¾as rti¾ai ID 802 by the ASIC 1.2 Firmware _* sttch ^' as Rsense- module I M .s-cutum on coittrolkr Ϊ 10 or ASIC 126 can coovsrt V¾> to a eisOTrce ^m.diamfcs* of he T4 mmg the itrrau m I ^' D

Wl m j;>. The AOC 132 primer ASIC 126 sy ss «niy determines a ceri spondiisg digital value for the esistance Eds. The. rsls^es Rds ena les an iofsreoee as the value of Vg ted the ch¾meteri$fe o tmasiste T Based on a value lor Vg, a value of Csersse be l a»d from the e a&iioi. ibt Vg shown above. A level ©fkk can then be desermirjed asd a the value of Cseme, ftKBSf te fee rsistance ds s deimBHt d, ^are VWSOM ays wlsicb the lev l mk ears be l¾uad For exam l , the measured Eds value cm be e tspars-d to a reierersce alue for R% or a table e:f ds. values expenhteat&lly determined to be associated wlls specific i k levels. W¾h m ink (e.g., a "dry" ^■ signal), or a ver l w ink level, i¾e valtse of sens ca acitor 353: Is very low., ilia results in. a vary few Vg (pn the ewter of 1.7 veto, and. the tvakaw tarisisiar 14 is off o nearly off ^* ( .., T4 is in ml offer subthresh ld operat a region). Therefore:, the .resrstaaee Rds from It! to grouud throug T4 - ud be ver high {e.g.., with 133 cu ent of 1 ,2mA, Rds Is typically above 12k. o m). Conversely, with a hi h nk level {*.■:·.. a'Wef signal), the -value όί sesrse capacitor 32 is elose to 1 0% of its t limg i a high -alue for Vg (on. the ode of 3.5

a high ^' fe level Eds is belo k ^' ohm, and is typicall a. f hundred ohms, |§0M| uuir ;s a eross-se onai vie of an Sample F!LS s«rsse stwiee

36 that iilistmies. both the ssme- capacitor 353 m*4 m ^' mitimk parasitic capacita-aee C l . *>?2) anderaotth the txtml plae 35$ that $y form part ^fswe eK acho 352, m^cor¾nc -wih varioos pleme«aioas. _: The msmse p¾¾bic cap-sciiaiKii Cp 1 973 may ¾e fomed by tbe meisl plae 355, ibe tsvl&do!* layer and sii slrale 344. As described .hereto, a P1.LS 22 may dsi rmm- m k le el based n the c& e½«ce vatee of sense ca acitor 352. Wbei a visage (e,g., Vp) is applied %ø. ike m l ptae 355 _» dmrgidg-dse seise eapaeiiar 2 feswever, the Cpl 972 ca dter a!s« charges Because of ibis, the arasitic eapacbase Cp I 972 may co ribate »s¾ lis o«Isr of 2ί)% of the cspadiasce etenMib d lor $g»se sapdtor 352. Tbs percentage may y depending m fbe thkfcBess. of the .tosulaiiow layer 356 md die dielectric eoisi tp of ibe iiisaS d a m terial, The c ffs reaiatotag m the parasitic eapacitaoee Cpl 972 to a "drv" stale (s>g,, where rto I A is pr¾seo) _: . however, vmy he enough m mm or? Sh 0¥¾!Μ!¼ΪΪ transisior 14 Tbe arasitic C l 72, therefore, may dilue the dry/wet signal

¾.>37 F igwre 10 s a o a^ect ra of m mmm k imrn 364 ti t ciiidm pm mc k ik d merit 1074, te ^' accordws w.¾h various implemerstai BS. The parastic lmbmisoa efcrae ΉΙ74 a com rise a eorAetlve layer 1 76 soeb as s p«lysiIico« layst - hich tmy be Ibrmed over m oxide 1077 pre oxide layer), dess ed to eliminate the impact of ibe paras c eapacitaaee Cpl Ψ72, .to ihk- nfigar»i«, when. a voltage (e.g., Vp} k applied to the raeia! plate 355, it may also be applied to the eooefsep e layer 1 Cr7o.. its v r la irrspiemerstatioos, this y pf!veM a charge frata developing ΟΪΪ ibe Cpl 972 so U« Cpl b e¾etiv* virtually is lated iwfc ter ination tsf die sense ca acitor 352 eanaet¾u«e. Cp2, fclemmt 38 may element ^| i ^} ?4. Cp2 HI? may slo the e&argisg speed of ihe p^.s¾k.elimmitk>« ^' eifeftis?si 1074 but may m act i tmmvdn km of cpim ec use ib h sufficient charge time- provided far demen 107.

#0381 Fi ure ! ! is xample PJIS ink level ssesor ^' circuit 366 with a parasitic dimmau n cm t 1. i i _f . dmnm m mi 368, arid shift register 3 8, ki aecor^awce w¾b vmm implm Mm, As noted hersin, clea ng resisto clrenn iS tmy fee aciivsid to purge ink aas or ink residue oil of a MLS llu chamb r 350 pn i tmm ing. to-seasor eireitlt at ID 802.. The dearing esistors 8 , R2, R3, md EC ros operate like typicsl Til tiring resistors, Thus, they rosy be addressed, fey dynamic TOmcsrv irniltipfemg (DMU 1 SS2 and driven hy a power FET 1184 connected io a ire line 1186, The -eeuirolkr 110 (Figure I) raa control adlvati&B of clearing resiitor elcnlt 368 tliroag die lire line ! 18 and OMUX ! I 82, by executi efpartkakr Mng msi ci m i n e arntg tnodnte 134, !fer esample.

i$M91 Typkali _s ami ti k se circuits 36 from -ran ttlpie FILS ! 22 ro y he e¾a««ci«d to a. common ID 102 tine..For exampfc a olor priotead di« ttbstraie 344 with several fluid feed ste 342 may have twelve or mo : PILS 122 (e.g., fea MLS 12:2 per slot 342, as in Flgnfe 3), The- shift register 348 nia esmhle multiplexing the oirtpas of saaulipl FILS sensor dro ts 366 s¾ © to- common D mi lim. A FILS select mocfa!e 136 exeenthag m the controltef 1.10 »iay co»ol the shift register 348 t provide a s ¾«@t § siii i, orner ordered u t of the mtiM fe. FILS sens« circtilis 366 onto common I 802.{.m |§04§i Fsgus 12 sto s aiorber xample of a stel! register 38 thai addesses mu&ipie PILS 122 signals, in accodance ith rious imptem ifom. hi Figare 12, a sh regste 348 coi«pr¾es a FILE block selective smi address .muftlpfe HiS signals from mejve MLS 122. Xhereare ttae .slots 342 (342a, 342% 342c) color dle, _: with f i F!LS 122 J¾t eac slot 342. For tm temeftistitms teladiffg mors thaa t ele Fits .122, tfe sluft register 4| may ki»iia co«.6g»red Ibr addressng the addition!. PILS 122, Addressing Ae multiple FILS signals tr ugh shit register 3 $ may increase the aeceracy of ink level m^ t&xm&s by cbeokmg w¾His locations on the dk

ί>0 ! I Various eperatbas of a raeiaod for f rra g a $Mi ejecti n aap&rariis i&cladbf a round decirode exposed to a fhrid cha e are Illustrated iii Figures 13- 21 by troy .of sectional views o f the ^■ apparatus at varbas stages of the i«e&o<i it should fos iioied that, various epmsk . discussed and/or illustrate a be geaeral!y referred to a multiple discrete speratbas ia-tara fo help in mim>waimg vsrioos imptem rnlmm. The order of deser ik sboald mi be c-oasi ed to Im thai Ibese operaboiB are order de e deW, wsfess esp!icitly stated. Moreover, m>t

imp&rn mi& may indudfe more or fewer operatons may be described, pM2J l¾tmi»g mm to Figare 13 , the first m tal layer 373 of ike sense straetsrr 346 may be f rmed over the s bstate 34 _> eith r directly or on sttotber layerfs) clirecly the substate 344, a the secon metal layer 375 may be formed o ver me first t M layer ¾†3. As sh **, Ibr exa le, the first mttsd layer 373 tmy e formed oo m insulator faf&t 356, wlfclt la an a substrat 344. |§043 At figure- 1 » 139( tttay be forme over t e first metal ayer 73 and the ma d metal layer 375, -and the -metal, layers 373,.375 may be etched, T e steh 0fK¾¾d ft at Figure 14 may be ptrf&tnsed an sutable eteh ope-ratost lrie¾tfcg, for example, a ptetaa dry efck

Although not tltasfTated in figures 13 and 14, m vm & imp tmt i the xm l p m 155 of the sem ca acitor 352 may he-focme s:tmw.H¾t¾eoiBly lis fbtnrisig the first meial layer 313 ,ικ! the s cond xmt&l layer 375,. In 1.55 of »w capacti 352. ma be fbrra&l sepaat ly to Ibr&iasg t¾e first .aaetal la er 373 and the $ onB. n*etat .layer 375,

At Figure- 15, a mask 1 be- formed o er sabstraie 344 aad over ortons: of the secaad rsetal layer 3?5« arid then -at Figure 16, the ¾o»d

375 imy be etched such, lb at a psttims pfthe first »si¾l fever 373 Is exposed ttamgh the second metal, layer 375 to allow the- fat s»eta! layer 373 o e exposd to the luid chamber 350 d scri ed herein,. In yariows im i«m»tatioas,.&e seeow! m tal layer 37S may ¾e etched ming y stsitable etc ope t a such as, for exam le, a we etch At figure 3 , tie trasfe 1 :9:2 may e teraoveil

fWM^l At gure 1 the assivati on layer 360 may e .teaed. over the metal layers 37 , 375 (and eve the metal plate 155 ©f he seme capacitor 352, though n©t iMtisiateit here), aod at Figure- 19, a taask 1394 t y be Ibrraed the psssivatioii layer 360. As si wit, the mask 1394 toel des at least ne openittf eimea &ndag to aiifjf!fi) at which th via 37 is to be formed. AtFl tie 20. t e &sdvatioit layer 30. ma be etched to t via 371 to expose a p tion of the first me½I layer 37310 provide a grosiisl electrode i¾r the sense circuit of the serts&sr. l e mask 1394 may be f$m $& at. Figue 21 d the method, y ϋ&βϋηη with om ore operati fts to iwm _f at east m. pad, e «&raei«re ^' fat exam l , as Figures 3-6, 9, and 1 , For «t»pt , the met od tita .radadt f«.ni» .a ®H¼ layer ©v«r the passivation ^' layer S6 io Ib?m the ik d chamter 3Si> bet een ik ¾s¾¾i livet 35<¾ asd ifee piwivaiion kyer 360 ssch ha the portJO» of the fet tm i layer 3 ?3 s «xpesed to h Siiid. e¾amfeet 50 and ihe Ihdd c am er 350 fttudiea y eoapies the MM f¾ d slot 342 io a :noz¾i© &.fdita¾¾¾fe la er 3.56,

MTf Although certain: iimplet¾€fttatiom aw e«a illustrated and describ d hereis, ¾ will he a precated by hose of ordinary skill m lie at ik a wide vark&y c a ^' ta¾ e assdot qidvaiea Impteaiestatiei calculated to aefev the -¾MC u oses i&a be su stituted for the implemes ad re; shown and. describ d without 4ep¾siisf from -the scope ef this disclosi.s», Those with skill is the art will tsadiy appreciate thai isi^lsmes lons tm be itnp1em«nt«d i® a wide variety o f ays, h application Is Intend d io sever my p m or variation oftfje i tpteeat iotJi dscusse hereis, M is iratnifigft!y intended., liweib , thai imptemesiaf is he lirahed «»Iy .by the claims: and t e equivalents thereat