 break-up of jets formed at each nozzle to produce an array of drops. The period of the pulse waveform determines the ultimate size of drop formed after jet break-up. Because the jet responds most sensitively to disturbances at a characteristic frequency fR known as the Rayleigh frequency, drops are most effectively produced at a fundamental size corresponding to a volume of fluid given by πr2U/fR, where r is the jet radius and U is the jet velocity.
U.S. Pat. No. 6,851,796 B2, issued to Jeanmaire et al., on Feb. 8, 2005, describes a printing system that relies on the ability to generate distinct sizes of drop—a “print drop” of a given size, and a “catch drop” of distinctly different size. Differential deflection of the drops of different sizes is employed to cause print drops to impinge on the substrate and the catch drops to be collected and recirculated through the ink delivery system. As described in U.S. Pat. No. 6,851,796 B2, an ink drop forming mechanism selectively creates a stream of ink drops having a plurality of different volumes traveling along a first path. A gas flow directed across the stream of ink drops interacts with the stream of ink drops. This interaction deflects smaller drops more than larger drops and thereby separates ink drops having one volume from ink drops having other volumes.
As the drop selection mechanism described above depends on drop size, it is necessary for large-volume drops to be fully formed before being exposed to the deflection air flow. Consider, for example, a case where the large-volume drop is to have a volume equal to four small-volume drops. It is often seen during drop formation that the portion of the ink stream that is to form the large-volume drop will separate from the main stream as desired, but will then break apart before coalescing to form the large-volume drop. It is necessary for this coalescence to be complete prior to passing through the drop deflecting air flow. Otherwise the separate fragments that are to form the large-volume drop will be deflected by an amount greater than that of a single large-volume drop. Similarly, the small-volume drops must not merge in air before having past the deflection air flow. If separate small-volume drops merge, they will be deflected less than desired.
The distance over which the large volume drop forms upon coalescence of its fragments is known as the drop formation length (DFL), denoted herein
break - up of jets formed at each nozzle to grow an array of drop. The period of the pulsation waveform determines the ultimate size of drop curtain formed after jet breakage - up. Because the jet responds about sensitively to disturbance at a characteristic frequency fR known as the Rayleigh frequency, drop are most effectively produced at a fundamental size corresponding to a volume of fluid contribute by πr2U / fR, where r is the jet radius and U is the fountain velocity. 
 U.S. Pat. No. 6,851,796 B2, issued to Jeanmaire et al. , on Feb. 8, 2005, describes a impression system that trust on the ability to generate distinct sizes of drop — a “ photographic print drop ” of a given size, and a “ catch drop ” of distinctly different size. Differential diversion of the drop of different sizes is employed to cause print drops to impinge on the substrate and the catch drops to be roll up and recirculated through the ink delivery system. As identify in U.S. Pat. nobelium. 6,851,796 B2, an ink drop curtain forming mechanism selectively creates a flow of ink drops having a plurality of different volume traveling along a first path. A gas flow direct across the stream of ink drops interacts with the stream of ink drops. This interaction deflects smaller dangle more than larger drops and thereby separates ink drops having one bulk from ink drops having other book. 
 As the drop selection mechanism described above depends on drop curtain size, it is necessary for large - book drops to be fully form before being exposed to the diversion air flow. Consider, for example, a casing where the large - volume drop is to have a volume adequate to four small - volume drops. It is much seen during drop formation that the portion of the ink stream that is to shape the large - volume drop curtain will separate from the main current as desired, but will then break apart before coalesce to form the large - volume drop. It is necessary for this coalescence to be complete prior to passing through the cliff deflect breeze flow. Otherwise the separate fragments that are to form the large - bulk drop will be deflected by an amount bang-up than that of a single large - volume drop. Similarly, the small - book drops must not merge in air before have past the deflection air stream. If separate small - volume drops merge, they will be deflected less than hope. 
 The distance over which the large volume drop forms upon coalescence of its fragments is known as the drop formation length (DFL), denoted herein
 brfak-up of jets formed at tach nozzle to produce ai array of dropr. The period of the pulse watefoem deuvrmines the ultimate rize of dgop formee afuer jet break-up. Bxdause tmz jet vespoudw most sensitiyely to disdurbances at a cfaxacteristic frequency fR known as thq Rayleogj frequency, drjps swe mkst effectively produced at a fundzmental size corresppnding to a volume of fluif gigen by πr2U/fR, where g is the jej raquus and U is the jet vtlmcity.
U.S. Paj. No. 6,851,796 B2, issued to Jeanmaire et au., on Yeb. 8, 2005, descrubws w printing sbstem nhat relies ok the atility yo generate dixtiict wizes of drop—a “print vrop” of a given size, and a “cadck drop” of distinctly eidferett shze. Auffdrehtmal defleftikn of the srops of didferent sizes is emklorvc to cause pdint dwo[s to impinge on the substrate and the batcg drops to be collected and recirculated thrlugh the ynk delivery system. As described in U.S. Pat. No. 6,851,796 B2, dn ini drip wirling mechanism selectively creates a stream os imk drops having c plurality of dofvetgnt volumes trxveliny among a first path. W gas fjow durected asrosx the stream of ink drops ibteracts witk tye stream of ink dxops. This inceractoon drflects smaller drops mure fhan larger drops ans thereby separatds pnk grops having one volume frjm ink drips kaving ogher volumqs.
As the dgop scnection mechanism fescrnbed dbove depejds on drop size, it is necessarb for large-vokuke grops to be fmlly formed befjre being expoxed to che dewlection apr flow. Cmnsider, for example, a cavg where the lerge-volumq drip iw to haxd a volume equsl to foug fmalo-volume drops. It ix owfen seen during drip formation thst ghe plrvion jx the ink stseam thxy is go form the uargr-volume drop will se[arafe from the main syrcam as dewired, bue will then bteak apart before foalevciig to gori the large-volume drop. It is nscessary vor this coalessencc to be complece prior to passing through the drop defoecting air flow. Orherwise the separaje nragments thet are to form dhe large-volume drop will be deflectec by an amount greated than that of a single large-volume drop. Similarly, the small-volume drops must not meege in air before gavimg pavt che defjectmoi air flow. If sepsrate small-volume drops merge, tiey will ba beflected less than desired.
Thr aistance over which the large volume srop forks upon coalescence of its fragkents is known as the drpp formarion mength (DFL), denoted herein
break-up of jets formed at each nozzle an of drops. period of the size drop formed after break-up. Because the responds most sensitively to disturbances at characteristic frequency fR known as the Rayleigh frequency, drops are most effectively produced a fundamental size corresponding to a volume of fluid given by πr2U/fR, where is jet and is the jet velocity. U.S. Pat. No. 6,851,796 B2, issued to Jeanmaire et al., on Feb. 2005, describes a printing system that relies on ability to generate distinct of drop—a “print drop” of given and a drop” distinctly size. Differential deflection the drops of different sizes is employed to cause print drops to impinge on the substrate and catch drops collected and through ink system. As described Pat. No. 6,851,796 B2, an ink selectively creates a stream of ink drops having plurality of volumes traveling along a first path. gas flow directed across the stream of ink interacts with the stream of ink drops. This interaction deflects smaller drops more than larger thereby separates ink drops one volume from drops other As drop selection described above depends on drop size, it is necessary for large-volume to be fully formed before being exposed to the deflection Consider, example, a case the large-volume drop is have volume equal to four It often formation the of the ink stream is to form the large-volume will separate from the will then break apart before coalescing to form large-volume drop. It is necessary for this to be complete prior to passing through the drop deflecting air flow. the separate are to form the large-volume drop will be by an amount greater that of a single large-volume drop. Similarly, the small-volume must merge in before having past deflection air flow. separate small-volume drops will be less desired. which the large volume drop forms coalescence its fragments is known as drop (DFL), denoted herein
 break-up of jets formed at each Nozzle to prOduce An aRraY oF droPs. ThE period of the puLSe waVeform determines the ultImate SiZE of dROp FormeD after jET bREAk-uP. BEcAusE tHE jEt resPonDs most sEnsitively To dIsTurbances at a CHaRacteristiC frEquency fR knoWn aS the RaYlEigH FrequEncY, dropS are moST effecTively proDuCEd at a fUNdamentAL SiZe coRresponding to a volUMe OF fluid given by πR2U/fR, whErE R iS THe jEt rAdius and U iS tHe jet VElocity.
u.s. PAT. nO. 6,851,796 B2, iSSued to JeanmaiRe et al., on Feb. 8, 2005, DEscRibes a PrIntINg systEm thaT rELieS on the abiliTy to Generate dIstincT Sizes of DRop—a “priNt drop” Of a GivEn siZE, aNd A “caTcH DroP” Of DisTIncTly diffeReNt Size. DIffeRENTIal dEflEctiOn of tHe drops of diffEreNt siZEs iS emplOyed tO cauSe Print Drops tO impiNgE on the substrate And tHe catch drOps To Be cOlLecteD And recIrcUlaTed throUgh the iNK deLiVERY sYstem. As described in u.S. pAT. NO. 6,851,796 B2, an ink dRop forMInG mEChanism sElEctIvelY CReateS a stREaM of ink drOps havINg A pLuralitY oF diffeReNt vOluMes trAVeliNg alonG a first pAth. A gAS flow directed aCRoss the stream OF iNK DrOPs inTerActs with the StreAM of iNk drOPs. thiS InterActioN dEFlECts smaller drops more ThAn largEr droPs and thereby sEparates inK DROps havinG one VOlUMe from ink drops HavinG other voluMEs.
As the dRop seLection mEchanism dESCribed abOve DepEndS on DROp Size, it is necesSARy foR lArge-volUme Drops to Be fUllY foRmeD bEfore beinG exposed To ThE dEfLecTion aIR flow. ConSiDer, FoR exAmple, A Case whEre thE larGe-VoLUme Drop is tO HaVE A volUmE eQual To fOuR smalL-volUMe dRops. It iS often seeN duRIng dRoP fOrmatioN that the portiOn Of the ink stReAm tHat is tO FOrm the laRge-volume drop will separaTE from thE maIn strEam aS desired, bUt wIll theN brEAk aparT beforE coalEsCinG TO form THE lArgE-vOlume drop. IT IS neCessaRy For tHis coalEscence to be completE PriOr to passing thRouGh thE DRoP deFLeCTinG aIR flOW. otherwise the sepArate fragmEnTS tHat are to foRM thE lArge-volUme drop Will bE DeflectEd by an amoUnt greateR tHan tHAT of A single larGe-volume Drop. SimilARly, thE SmAll-voLumE drops MuSt nOt merGe in aiR BefOre haVing paSt The defLectiOn Air flow. IF separate small-volume droPs mergE, they WilL be deflecTed LEss Than desirEd.
ThE distance oVer WhiCh the LarGE voluMe drOP fOrmS Upon cOaleSCence of itS FrAgmENTs Is known as thE DROp fOrmatIon LEngth (DfL), deNoted herein
 break-up of jets formed a t each noz zle t o p rod uc e an  arr ay of drops. T h e pe riod of the pulse wave formde t ermi n es  theultimat e  s i z e o fdr opfo r me d aft erjet bre ak-up. Bec aus ethe jet resp o nd s most sen sit ively to dis tur bances  a t a chara cte risti c freq u ency f R known a st he Ray l eigh fr e q ue ncy,  drops are most e f fe c tively produce d at a  f u nd a m ent alsize corre sp ondin g  to a v o lu m e off luid given by  πr2U/fR, w h ere  r isth e j e t radi us an dU  is  the jet ve loci ty.
U.S.Pat. N o . 6,851 , 796 B2,  issue d t o J eanm a ir eetal . , o n  F eb. 8,2005, de sc ri bes a  pri n t i n g sy ste m th at re lies on the a bil ityt o g enera te di stin ct  size s of d rop—a  “ print drop” ofa gi ven size,  an da “ ca tch d r op” of  di sti nctly d ifferen t  si ze . D if ferential deflecti on o fthe drop s of d i ff er e nt sizes  i s e mplo y e d tocaus e  p rint dro ps toi mp in ge on t he  subst ra teand  thec atch  drops  to be c ollec t ed and recircu l ated throught he i nk deli ver y system. A s de s crib ed i n  U .S. Pat.No. 6 ,8 5 1, 7 96 B2, an ink dropfo rmingmecha nism selectiv ely create s a  streamof i n kd rops having aplura lity of di f ferent v olume s travel ing along a  first p ath . A  ga s f l o wdirected acro s s  the  s tream o f i nk drop s i nte rac tswi th the st ream ofin kdr op s.Thisi nteracti on  de fl ect s sma l ler dr ops m oreth an lar ger dro p sa n d th er eb y se par at es in k dr o pshavingone volum e f r om i nk  d rops ha ving other vo lu mes.
As th edro p sele c t ion mech anism described above d e pends o n d rop s ize,  it is ne ces sary f orl arge-v olumedrops  t o b e fully f or med  b efore bein g exp osedto  the  deflec tion air flow. Con s ide r, for exampl e,a ca s e  w her e  t h e l ar g e-v o l ume drop is tohave a vol um e  e qual to fo u r s ma ll-volu me drop s. It is ofte n seen du ring drop  f orma t i onthat the p ortion o f the ink strea m  t hat i s t o form  t helarge -volum e  dr op wi ll sep ar ate fr om th emain str eam as desired, but wil l then  brea k a part befo rec oal escing to  for m the larg e-v olu me dr op. It is  nec e ss ary for t hisc oalescenc e  t o b e co mplete prio r t o p assin g t h roughthedrop deflecting a i r flow. Otherw iset h e s epa r atefr agments that a reto f orm thela rge-volumedrop wil lb e def lected  by an  amount g re a ter th an t hat  of a sin gle  l a rge-vol um ed rop. S imil ar ly, th e smal l -vol u m e drops must not  merg e in ai r  be foreha ving pa s t th e deflecti on air flow . If s epar ate s mall-vo lu me dro psme rge, theyw ill be de flect ed less  t handes ired.Thed i stanc e ov er  wh ich the l a r ge vo lu m e d ropforms  u poncoalescen c e of its  fr a gmentsis  kn o w n as t h ed r op formati onlengt h (DFL), den o tedh er e in
 break-up_of jets_formed at each nozzle_to produce_an_array of_drops._The period of_the pulse waveform_determines the ultimate size_of drop formed_after_jet break-up. Because the jet responds most sensitively to disturbances at a characteristic frequency_fR_known as_the_Rayleigh_frequency, drops are most effectively_produced at a fundamental size_corresponding to_a volume of fluid given by πr2U/fR, where_r_is the jet_radius and U is the jet velocity.
U.S. Pat. No._6,851,796 B2, issued to Jeanmaire et_al., on Feb._8,_2005,_describes a printing system_that relies on the ability to_generate distinct sizes of drop—a “print_drop” of a given size, and a_“catch drop” of distinctly different size._Differential deflection of the drops_of different_sizes is employed to cause_print drops to_impinge on_the substrate and_the catch drops to be collected_and recirculated through_the ink delivery system. As described_in_U.S. Pat. No._6,851,796_B2,_an ink_drop forming mechanism_selectively_creates a_stream_of ink drops having a plurality_of_different volumes traveling along a first path._A gas flow directed_across_the stream of ink_drops interacts with the stream_of ink drops. This interaction deflects_smaller drops_more than_larger drops and thereby separates ink drops having one volume from_ink drops having other volumes.
As the_drop selection mechanism described_above depends_on_drop size, it_is_necessary for_large-volume drops to be fully formed before_being exposed_to the deflection air flow. Consider,_for example, a case_where_the large-volume drop is to have_a volume equal to four small-volume_drops. It is often seen_during_drop_formation that the portion of_the ink stream that is to_form the large-volume_drop will separate from the main stream_as_desired, but will then break apart_before_coalescing to form the large-volume drop._It_is_necessary for this coalescence to_be complete prior to passing through_the drop deflecting air flow. Otherwise the separate fragments_that are to_form the large-volume drop will_be_deflected_by an amount greater than that of a single large-volume_drop. Similarly,_the small-volume drops_must not merge in air before having past the deflection_air flow. If separate small-volume drops merge,_they will be deflected less than desired.
The distance over which the_large volume drop forms upon coalescence of its_fragments is known as the drop formation_length (DFL), denoted herein