CA1305855C - Coating apparatus having a blade with metallic and compressible layers - Google Patents
Coating apparatus having a blade with metallic and compressible layersInfo
- Publication number
- CA1305855C CA1305855C CA000570459A CA570459A CA1305855C CA 1305855 C CA1305855 C CA 1305855C CA 000570459 A CA000570459 A CA 000570459A CA 570459 A CA570459 A CA 570459A CA 1305855 C CA1305855 C CA 1305855C
- Authority
- CA
- Canada
- Prior art keywords
- web
- coating apparatus
- layer
- coating
- blade
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface
- B05C11/04—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface with blades
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface
- B05C11/04—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface with blades
- B05C11/045—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface with blades characterised by the blades themselves
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
- D21H25/08—Rearranging applied substances, e.g. metering, smoothing; Removing excess material
- D21H25/10—Rearranging applied substances, e.g. metering, smoothing; Removing excess material with blades
Landscapes
- Coating Apparatus (AREA)
- Paper (AREA)
- Inking, Control Or Cleaning Of Printing Machines (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
Abstract A web coating apparatus is disclosed in which the coating material is smoothed onto and excess coating material is removed from the web by a downstream blade comprising a metalic layer and a compressible layer on its upstream side.
Longer wear of the blade is achieved by the fact that the compressible layer preserves a wedge of coating material adjacent the web even after the distal end of the metalic layer has become worn.
Longer wear of the blade is achieved by the fact that the compressible layer preserves a wedge of coating material adjacent the web even after the distal end of the metalic layer has become worn.
Description
~ACK~RO~ND OF THE I~VE~IO~
PIELD OF THE INVENTION
T~ lnventlon relate~ to ~ co~tins ~pparatu0 foc applylng a coating onto a web, More speclfically, tkl~
lnvention relates to ~ coating apparatus ln whlch the bl~de lncludes a metallic lAyer -and ~ contlguous co~pres~ible layer di6posed upstream relatlve to the metalllc laye~.
~ OR~ATION DISC~OSURE STATEMENT
In the web coati.ng art, a web of paper or the like to be coated 18 typically gulded over a rotatable b~cking eoll.
one method o~ applying coatlng materlal ~ncludes applying pre~surized co~tlng materlal to the web with the web dl~posed between the coatlna material and the backing roll. Exces8 coating ~aterial i8 re~.oved ~rom the web by a trailing ~et~ring blAde, Such an arrangement 1~ known ln the art as ~hort dwell coating~.
Anotber coating technlque known ln the art a~
~flooded nip coating includea dipplng an applicator roll lnto a contAin~r su~plled with the coatlng ~aterial such that the appllc~tor roll rotates and applles A relatively thln layer o~ coating materlal to the web. A blad~ 1~
dlsposed downstream relative to the appllcator ro'l for ~moothlng ~nd re~oving e~ce~ coating.materlal fro~ the coated web.
~3~
~2 ln both of the afore~entioned co~tlng procedure~, ~
ce~lllent metalllc meterln~ blade i~ dl~po~ed down6txeam relat~ve to the ~pplic~tlon of coating ~Aterlal onto the web, However, ~fter p~olonged usage o~ the aforementlone~
meteclng blades, such bl~des tend to wear thereby causlng ~t~eaklng of the re~ult~nt co~tlng.
More specl1cally, a typical bl~de lnclude6 a dlstal end di~po6e~ ad~acent to the web, The dlstal end includes a t~p and ~ heel dlsposed upst~ea~ rel~tlve to the tip.
~he dlstal end ~s machlned ~uch that a wedge-8haped 6pACe is di6~0~ed between the distal end of the blade ~nd the web, the wedge-~ha~ed space be;ng deflned by the web and the di~t~ end of the blade between the t~p a~d the heel.
~owever, a~ the tlp we~ts down Cue to contact wlth the web, the wedge-~haped space decreases untll the d~st~l end of the blade between the tip and the heel ~6 di6po6ed substanti~lly t~ngentially relative to the web and backing roll. Such wear causea tu~bulence of the coatlng m~terial and nonunifo~m coAtlng and streaking of the re~ultant coatee web.
~ he pre~ent lnYention overco~es the a~orementlone~
proble~ by provldlng a compcessible layer ~3pose~
contlguou61y wlth ~nd upstre~m relAtiYe to the met~ c l~yer of the blade. The compre~6ib~e l~yec ef~ectively lnc~e~se6 the th~ckne66 of the blade ~nd con6eq~ently lncre~ses the length of the wedge-shaped ~p~ce cuch that the wedge-~haped ~pace extend~ fro~ the tlp of the retAlllc layer to the heel of the cor.,pres~lble layer, Durlng use of the blade, as the ~etalllc laye~ weacs, ~he ~s~
(3) compcess~ble l~yer i9 co~,pre~sed due to the buil~-up of coatlng withln the wedge-shaped ~p~ce. Such compres~on of the compres-~jble layer malnt~ins the wedge-~haped cpace the~eby ~ini~izing the flow turbulence in the vlclnity of the distal ~nd of the blAde 80 that a smooth layer of coating i9 applied to the web and the ltfe of the blade i6 prolonged.
Therefo~e lt i9 ~ prlmary ob~ectlve of the pre6ent invention to provide a coatlng apparatu6 whlch overco~es the afore~,entloned inadequacles of the prior art peop~sals by the provision o~ A blade havlng a ~e~llic lAyer and a compre~lble layer dlsposed con~lguously hith and up6t~eam r~l~tlve to the met~llic l~yer.
Although the present lnvention will be described partlcularly rel~tlve to the ~pplicat~on of A coating materi~l by means of a short dwell ~oater or a flooded nlp coater, lt will be underfitood by tho6e 6kliled in the art that the present ~nvention i6 equally appllc~ble to a 812ing press, varnl~h coater, pa~te coater or the appllcation of an ink film to ~ prlnting ~oller.
S~MMARY 0~ ~HE ;~VENTION
~ he present lnventlon relate6 to ~ coating app~ratu~
for applylng a coatlng onto n web whlch 1~ movably ~uppo~ted by a rotat~ble backlng roll. The apparatu~
lncludes a s~oothing blade whlch 18 d~posed ad~acent ~o the web for smoothing and metering the coatLng onto the web. ~he blade includes a metallic layer ~.aving a di6tal end di6po~ed ad~acent t~ the web, The blade al80 includes 5~
~4) a compres~lble l~yer whlch ls dispo~ed contlguously and upstream relatlve to the met~lllc layez. The com~res~lble layer h~s a dl~t~l end such thdt durlng use of the apparatu~, as the dist~l end of the metallic layer wear~
away, the d~tal end of the compres~lble lsyer 1~
compresse~ by the coa~ing 80 that ~ wedge of the coating 1~ dl~po6ed between the web ~nd the blade. The wedge i~
deflned by the web, the dictal end of the ~et~lllc l~yer and the co~pre6~ed dl~t~l en~ c~ the co~pres61ble layer thereby m~lntainlng a s~ooth ~pplicatian of the coatlng onto the web and a prolonging of the ll~e of the blade.
More specifleally, the coatlng appar~t~ o the pre6ent lnventlon 18 applleable to a ~hort-dwell coater.
Alternatl~ely, the coa~lng apparatu~ o~ the p~eaent lnventlon i8 appllcable to A flooded nlp coater.
In either of the aforementloned appllcatlons of the pre6ent lnventlon, the metallic layer 1~ of 8prlng 6teel plate and the comp~es61ble l~yer i6 of a polymeric materlal. ~n a specl~ic em~odiment of the pre~ent l~ventlcn the polymer1c materlal ls rubbez and ~he ratio of the thlckness of the met~lllc l~yer to the thlckness of the compre~slble l~yer 16 1:2, ~ he metalllc layer has a thlckne~6 w~tbin the rAnge .3 to .7 mllll~eters and the co~pre6~1ble layer has A
thlckness wlthin the r~nge .8 to 1.2 r,llllmeter6, The h~rdness o~ the web 1~ gre~ter than the hardne6s of the co~presslble layer and the compr~lble layer i8 ~abrlcated frQm a matezldl whlch i8 co~patlble wlth the color o~ the web to te coated.
~3~
ts) Although the preferred e~bodlmer.t of the p~esent lnve~tion wlli be described herelnafter, lt will be understood by tho~e skllled ln the ~rt that many mDdlflcatlons An~ v~r~tlons of the p~esent inventlon ~ay be carrled out wlthout ~epartlng from the sport ~nd scope of the present inventlon a8 ~efined by the claim~.
~R~EP DESCR PTION OF TH~ DRAwINGS
Flgure 1 $s a per~pective view of ~ p~lor ~rt 6hoct dwell coater~ .
Flgure 2 1B a per~pective view o~ a priol art ~looded n~p coater~
Flgure 3 18 an enlarged ~ection~l v$ew 3howlng the dl6tal end o~ a prlor ~tt metallic ~ete~ing bla~e showing tke tlp, the heel and the wedge-shaped space between the bl~de and ~he webs F~gure 4 1~ an enl~rged sectlonal view o~ oothlng blA~e ac~ordln~ to the ~esent lnvention showing the we~ge-6haped BpaCe extendlng f~o~ the tip of the metalllc layer to the heel of the compre~slble layer. The blade shown in fl~ure 4 16 ~hown be~ore we~rlns down of the metalllc layer has occuseed~
~ lgure 5 i~ a ~lmllar vlew to that ~hown ln flgure 4 but show~ the metalllc l~yes havlng worn down dur~ng U8C
of the apparatus but w$th the compreE6ibie layer ~lntalnlng a wedge of coatlng~
P$gure 6 18 ~ perspect$ve view 6ilnllAr to that shown in ~igure 1 but using the smooth$ng blade of the present :l~C~ $
(6) lnventlon thereby inhlbltlr.g strekking of the web A6 lndlcated in flqure 11 ~nd Figure ~ 1~ & per~pec~iYe vlew 61mil~r to that shown in ~igure 2 but using a smoothlng blade accordlng to the pre6ent lnventlon thereby inhiblting 6treaklng of the web as shown in f igure 2.
Similar reference chalacters refer to similar pa~tq throughout the ~ar lous e~.bodi~ents 0c the present invent ion .
DE~AILED DESCRIPT~O~I OF THE D~AWI~GS
_ ~ . . ...__ _ ~
P~gure 1 i8 ~I per~pectlve vlew of ~ typical pr~or art short dwell coater in whic~. A ~eb 1~ extends around a bAcking roll 12. A short dwell coater generally de~ignated 14 supplies p~essullzed coating m~terl~l 16 to the web lG an~ a ~etering blade 18 ~e~oves exce~s coatlng mateclal ro~ the coate~ surace o~ the web. As ~hown in flgure 1, a~ter prolonqed usage of the blade 18, there exlsts a tendency for the coatlng to become streaked as ~ndlcated by 20. Addit~onally, flgure 1 show~ a doctor 22 and c~e~ning f'luid 24 dl~posed upstrea~, relative to th~
~ort dwell coatlng appar~tus 14.
Flgure ~ shows a typlcal prlor art 100ded nlp co~ter generally de~lgnated 14A for coating a web lOA moYably extend~ng around a rot~table backinq roll 12A. The f looded nip coater 14A includes a supply of coatlng ~terial 16A and a rotatAble applicator roll 30. A
metering bla~e 18A i~ disposed downstrea~ relative to the applicator roll ~0. Rowevee, during prolonged u~age o~
~7) the bl~de :8A, there exist~ a tendency foe the coatlng to ~tre~k a8 shown by 20A ln fl~ure 2. Addltionally, a doctor 22A and cle~ning fluld 24A are BhOW" dlBpO~ed upstream relatlve to the flooded nlp coater 14A.
Plg~re 3 18 an enlarged 6ectlon~1 vlew of a typical ~etalllc meterlng blade 18~. The blade 1&3 lncl~des a C~stal end 32 havlng ~ t~p 34 and a heel 36. A web 10~ 16 dlspo~ed between the di~tal end 32 and a b~cking roll 12~
such that a wedge-~ha~ed space 38 i6 dl6posed between the web 10B ~nd the d~s~al end 32. The wedge-6haped ~paee 38 18 deflned by the web lOB and the dls~al end 32 of the blade 18B between the tip 34 A~d the heel 36.
Durlng prolonged usage of the bl~e 1~B, the tlp 3 of the blade 1~3 tends to wear until the distal end 32 between the tlp 34 and the heel 36 becomes substan~lally tangentlal relatlve to the ~urface of the ~eb 10~.
Pigure q 18 an enlarged -Rectlonal ~lew of the smoothlng blade generally deslgnated 18C accordlng to the pr~sent invention and 6hows the blade 18C aY includlng a me~cl~lc layer 50 having d di~tal end ~2 ~nd ~
co,~prea61ble layer 54 dispoaed c~ntlguouo:y wlth and up6tream relatlve to the metalllc laye~ 50. The compre~sible l~yec 54 includes ~ d~tal end 56 ~uch that ~
wedge-shaped apace 36C i~ di~po~ed between the web lOC ~nd the blade laC. ~he wedge-~haped ~pace 38C i~ de~ined by the web lOC and the distal ends 52 and 56 of the metall~c layer 50 and the compre66ible layer 54 between the tip 34C
of the retalllc layer 50 and the heel 36C of the coTpressible layer 54.
~s~
(B) Pig~re ~ ~how~ the blade lBC accordlns to the pre~ent i.nventlon before the metalllc layer $0 wears down due to prolonged usage o~ the coatlng appae~t~. $n a preferred embodl~ent of the pre~ent Lnventlon, the me~alllc l~yer SC
i8 fabrlcate~ fron spring 6teel plate h~vlng a thlckne~s ~1 of .5mm and the comprecslble layer 50 19 ~abrlcated fro~ rubber and has a thickne6s T2 of lm~. Therefore the dlstance between the t~p 34C ~n~ ~he heel 36C ls at le~t three tlmes that of a conventional blade.
Figure 5 i6 a 6imilar view to that .shown ln flgure 4 but show~ the metallic layer 50 h~vlng been worn down duclnq p~olonged usage such that the distal end 52 o~ the ~etalllc layer 50 i6 dlsposed substant~ally tansentially relatlve to the web lOC. However, the co~pces~lble l~yer 54 du~ing usage ls compres~ed by the co~ting m~terial wlthln the wedge 38C such that ~ wedge of coa~lng mater~al 18 m~lntAlned upstrea~ of the metallic layer 50. By this means turbulence of the coating materlal ln the vicinity ~f the blade lBC iG minl~ized and streaklng o~ the reYultant coated web is inhibited. Furthe~more, bec~u~e the compre~slbl~e layee 54 ~ always co~.pre6~ed by the coatlng mnterial and not worn aw~y by the same, the life of the blade accord~ng to the present inventlon is subst~ntlAlly prolonged, Plguee6 6 and 7 show the blade 18D and 18~ according to the present lnventlon ~pplled to ~ shoet dwell coater and to a elooded nlp coater re6pectlvely for lnhlbitlng streaklng of coated web~.
13~
~g) In the Frefer~ed e~bodlment of the present inventlon, the hardness of the ~eb lOC i~ geeater th~n the hardneP~
of the co~pre~sible iayer 54 ~nd the cor.,pre3sible layet 54 18 fabrlc~ed from whl~e rubber ~o a~ to ovold marklng of the web ln the event of the rubber l~yer 54 comlng lnto cont~ct wlth the surface o~ the web lOC.
In operatlon of the coating apparatus accordlng to the pLe6ent lnvent~on, the we~ lOC 1~ mov~bly supported by rotatable b~cklng roll 12C cuch that the web lOC moves p~st the wedge-shaped space 38C between the web lOc and the bl~de l~C. Co~tlng material is smoothed and meterea onto the web lDC by the blAde lBC and even after prolonged usage of the blade laC the wedge-sh~ped space 38C ~
m~lntalned between the bl~de l~C and the web lOC ~o that turbulence of the coating 18 minlmized there~y lnhlbiting etreaklng Or the coatlng and prolonglng the llfe of the blade.
3y the prov'6ion of the blade according to the pre6ent lnventlon, homogeniz~tion of the coatlng mateeial 1~ lmproved thu4 lmproving the quality o~ the ee~ult~nt coatlng.
~ n an ~pplication of the blade accordlng to the present lnventlon, coating ~ates were lncrea~ed to 2,400m per mlnute before streaklng occurred whereas only 800m per mlnute were posslble be~ore streakln~ using prlor art blade~.
PIELD OF THE INVENTION
T~ lnventlon relate~ to ~ co~tins ~pparatu0 foc applylng a coating onto a web, More speclfically, tkl~
lnvention relates to ~ coating apparatus ln whlch the bl~de lncludes a metallic lAyer -and ~ contlguous co~pres~ible layer di6posed upstream relatlve to the metalllc laye~.
~ OR~ATION DISC~OSURE STATEMENT
In the web coati.ng art, a web of paper or the like to be coated 18 typically gulded over a rotatable b~cking eoll.
one method o~ applying coatlng materlal ~ncludes applying pre~surized co~tlng materlal to the web with the web dl~posed between the coatlna material and the backing roll. Exces8 coating ~aterial i8 re~.oved ~rom the web by a trailing ~et~ring blAde, Such an arrangement 1~ known ln the art as ~hort dwell coating~.
Anotber coating technlque known ln the art a~
~flooded nip coating includea dipplng an applicator roll lnto a contAin~r su~plled with the coatlng ~aterial such that the appllc~tor roll rotates and applles A relatively thln layer o~ coating materlal to the web. A blad~ 1~
dlsposed downstream relative to the appllcator ro'l for ~moothlng ~nd re~oving e~ce~ coating.materlal fro~ the coated web.
~3~
~2 ln both of the afore~entioned co~tlng procedure~, ~
ce~lllent metalllc meterln~ blade i~ dl~po~ed down6txeam relat~ve to the ~pplic~tlon of coating ~Aterlal onto the web, However, ~fter p~olonged usage o~ the aforementlone~
meteclng blades, such bl~des tend to wear thereby causlng ~t~eaklng of the re~ult~nt co~tlng.
More specl1cally, a typical bl~de lnclude6 a dlstal end di~po6e~ ad~acent to the web, The dlstal end includes a t~p and ~ heel dlsposed upst~ea~ rel~tlve to the tip.
~he dlstal end ~s machlned ~uch that a wedge-8haped 6pACe is di6~0~ed between the distal end of the blade ~nd the web, the wedge-~ha~ed space be;ng deflned by the web and the di~t~ end of the blade between the t~p a~d the heel.
~owever, a~ the tlp we~ts down Cue to contact wlth the web, the wedge-~haped space decreases untll the d~st~l end of the blade between the tip and the heel ~6 di6po6ed substanti~lly t~ngentially relative to the web and backing roll. Such wear causea tu~bulence of the coatlng m~terial and nonunifo~m coAtlng and streaking of the re~ultant coatee web.
~ he pre~ent lnYention overco~es the a~orementlone~
proble~ by provldlng a compcessible layer ~3pose~
contlguou61y wlth ~nd upstre~m relAtiYe to the met~ c l~yer of the blade. The compre~6ib~e l~yec ef~ectively lnc~e~se6 the th~ckne66 of the blade ~nd con6eq~ently lncre~ses the length of the wedge-shaped ~p~ce cuch that the wedge-~haped ~pace extend~ fro~ the tlp of the retAlllc layer to the heel of the cor.,pres~lble layer, Durlng use of the blade, as the ~etalllc laye~ weacs, ~he ~s~
(3) compcess~ble l~yer i9 co~,pre~sed due to the buil~-up of coatlng withln the wedge-shaped ~p~ce. Such compres~on of the compres-~jble layer malnt~ins the wedge-~haped cpace the~eby ~ini~izing the flow turbulence in the vlclnity of the distal ~nd of the blAde 80 that a smooth layer of coating i9 applied to the web and the ltfe of the blade i6 prolonged.
Therefo~e lt i9 ~ prlmary ob~ectlve of the pre6ent invention to provide a coatlng apparatu6 whlch overco~es the afore~,entloned inadequacles of the prior art peop~sals by the provision o~ A blade havlng a ~e~llic lAyer and a compre~lble layer dlsposed con~lguously hith and up6t~eam r~l~tlve to the met~llic l~yer.
Although the present lnvention will be described partlcularly rel~tlve to the ~pplicat~on of A coating materi~l by means of a short dwell ~oater or a flooded nlp coater, lt will be underfitood by tho6e 6kliled in the art that the present ~nvention i6 equally appllc~ble to a 812ing press, varnl~h coater, pa~te coater or the appllcation of an ink film to ~ prlnting ~oller.
S~MMARY 0~ ~HE ;~VENTION
~ he present lnventlon relate6 to ~ coating app~ratu~
for applylng a coatlng onto n web whlch 1~ movably ~uppo~ted by a rotat~ble backlng roll. The apparatu~
lncludes a s~oothing blade whlch 18 d~posed ad~acent ~o the web for smoothing and metering the coatLng onto the web. ~he blade includes a metallic layer ~.aving a di6tal end di6po~ed ad~acent t~ the web, The blade al80 includes 5~
~4) a compres~lble l~yer whlch ls dispo~ed contlguously and upstream relatlve to the met~lllc layez. The com~res~lble layer h~s a dl~t~l end such thdt durlng use of the apparatu~, as the dist~l end of the metallic layer wear~
away, the d~tal end of the compres~lble lsyer 1~
compresse~ by the coa~ing 80 that ~ wedge of the coating 1~ dl~po6ed between the web ~nd the blade. The wedge i~
deflned by the web, the dictal end of the ~et~lllc l~yer and the co~pre6~ed dl~t~l en~ c~ the co~pres61ble layer thereby m~lntainlng a s~ooth ~pplicatian of the coatlng onto the web and a prolonging of the ll~e of the blade.
More specifleally, the coatlng appar~t~ o the pre6ent lnventlon 18 applleable to a ~hort-dwell coater.
Alternatl~ely, the coa~lng apparatu~ o~ the p~eaent lnventlon i8 appllcable to A flooded nlp coater.
In either of the aforementloned appllcatlons of the pre6ent lnventlon, the metallic layer 1~ of 8prlng 6teel plate and the comp~es61ble l~yer i6 of a polymeric materlal. ~n a specl~ic em~odiment of the pre~ent l~ventlcn the polymer1c materlal ls rubbez and ~he ratio of the thlckness of the met~lllc l~yer to the thlckness of the compre~slble l~yer 16 1:2, ~ he metalllc layer has a thlckne~6 w~tbin the rAnge .3 to .7 mllll~eters and the co~pre6~1ble layer has A
thlckness wlthin the r~nge .8 to 1.2 r,llllmeter6, The h~rdness o~ the web 1~ gre~ter than the hardne6s of the co~presslble layer and the compr~lble layer i8 ~abrlcated frQm a matezldl whlch i8 co~patlble wlth the color o~ the web to te coated.
~3~
ts) Although the preferred e~bodlmer.t of the p~esent lnve~tion wlli be described herelnafter, lt will be understood by tho~e skllled ln the ~rt that many mDdlflcatlons An~ v~r~tlons of the p~esent inventlon ~ay be carrled out wlthout ~epartlng from the sport ~nd scope of the present inventlon a8 ~efined by the claim~.
~R~EP DESCR PTION OF TH~ DRAwINGS
Flgure 1 $s a per~pective view of ~ p~lor ~rt 6hoct dwell coater~ .
Flgure 2 1B a per~pective view o~ a priol art ~looded n~p coater~
Flgure 3 18 an enlarged ~ection~l v$ew 3howlng the dl6tal end o~ a prlor ~tt metallic ~ete~ing bla~e showing tke tlp, the heel and the wedge-shaped space between the bl~de and ~he webs F~gure 4 1~ an enl~rged sectlonal view o~ oothlng blA~e ac~ordln~ to the ~esent lnvention showing the we~ge-6haped BpaCe extendlng f~o~ the tip of the metalllc layer to the heel of the compre~slble layer. The blade shown in fl~ure 4 16 ~hown be~ore we~rlns down of the metalllc layer has occuseed~
~ lgure 5 i~ a ~lmllar vlew to that ~hown ln flgure 4 but show~ the metalllc l~yes havlng worn down dur~ng U8C
of the apparatus but w$th the compreE6ibie layer ~lntalnlng a wedge of coatlng~
P$gure 6 18 ~ perspect$ve view 6ilnllAr to that shown in ~igure 1 but using the smooth$ng blade of the present :l~C~ $
(6) lnventlon thereby inhlbltlr.g strekking of the web A6 lndlcated in flqure 11 ~nd Figure ~ 1~ & per~pec~iYe vlew 61mil~r to that shown in ~igure 2 but using a smoothlng blade accordlng to the pre6ent lnventlon thereby inhiblting 6treaklng of the web as shown in f igure 2.
Similar reference chalacters refer to similar pa~tq throughout the ~ar lous e~.bodi~ents 0c the present invent ion .
DE~AILED DESCRIPT~O~I OF THE D~AWI~GS
_ ~ . . ...__ _ ~
P~gure 1 i8 ~I per~pectlve vlew of ~ typical pr~or art short dwell coater in whic~. A ~eb 1~ extends around a bAcking roll 12. A short dwell coater generally de~ignated 14 supplies p~essullzed coating m~terl~l 16 to the web lG an~ a ~etering blade 18 ~e~oves exce~s coatlng mateclal ro~ the coate~ surace o~ the web. As ~hown in flgure 1, a~ter prolonqed usage of the blade 18, there exlsts a tendency for the coatlng to become streaked as ~ndlcated by 20. Addit~onally, flgure 1 show~ a doctor 22 and c~e~ning f'luid 24 dl~posed upstrea~, relative to th~
~ort dwell coatlng appar~tus 14.
Flgure ~ shows a typlcal prlor art 100ded nlp co~ter generally de~lgnated 14A for coating a web lOA moYably extend~ng around a rot~table backinq roll 12A. The f looded nip coater 14A includes a supply of coatlng ~terial 16A and a rotatAble applicator roll 30. A
metering bla~e 18A i~ disposed downstrea~ relative to the applicator roll ~0. Rowevee, during prolonged u~age o~
~7) the bl~de :8A, there exist~ a tendency foe the coatlng to ~tre~k a8 shown by 20A ln fl~ure 2. Addltionally, a doctor 22A and cle~ning fluld 24A are BhOW" dlBpO~ed upstream relatlve to the flooded nlp coater 14A.
Plg~re 3 18 an enlarged 6ectlon~1 vlew of a typical ~etalllc meterlng blade 18~. The blade 1&3 lncl~des a C~stal end 32 havlng ~ t~p 34 and a heel 36. A web 10~ 16 dlspo~ed between the di~tal end 32 and a b~cking roll 12~
such that a wedge-~ha~ed space 38 i6 dl6posed between the web 10B ~nd the d~s~al end 32. The wedge-6haped ~paee 38 18 deflned by the web lOB and the dls~al end 32 of the blade 18B between the tip 34 A~d the heel 36.
Durlng prolonged usage of the bl~e 1~B, the tlp 3 of the blade 1~3 tends to wear until the distal end 32 between the tlp 34 and the heel 36 becomes substan~lally tangentlal relatlve to the ~urface of the ~eb 10~.
Pigure q 18 an enlarged -Rectlonal ~lew of the smoothlng blade generally deslgnated 18C accordlng to the pr~sent invention and 6hows the blade 18C aY includlng a me~cl~lc layer 50 having d di~tal end ~2 ~nd ~
co,~prea61ble layer 54 dispoaed c~ntlguouo:y wlth and up6tream relatlve to the metalllc laye~ 50. The compre~sible l~yec 54 includes ~ d~tal end 56 ~uch that ~
wedge-shaped apace 36C i~ di~po~ed between the web lOC ~nd the blade laC. ~he wedge-~haped ~pace 38C i~ de~ined by the web lOC and the distal ends 52 and 56 of the metall~c layer 50 and the compre66ible layer 54 between the tip 34C
of the retalllc layer 50 and the heel 36C of the coTpressible layer 54.
~s~
(B) Pig~re ~ ~how~ the blade lBC accordlns to the pre~ent i.nventlon before the metalllc layer $0 wears down due to prolonged usage o~ the coatlng appae~t~. $n a preferred embodl~ent of the pre~ent Lnventlon, the me~alllc l~yer SC
i8 fabrlcate~ fron spring 6teel plate h~vlng a thlckne~s ~1 of .5mm and the comprecslble layer 50 19 ~abrlcated fro~ rubber and has a thickne6s T2 of lm~. Therefore the dlstance between the t~p 34C ~n~ ~he heel 36C ls at le~t three tlmes that of a conventional blade.
Figure 5 i6 a 6imilar view to that .shown ln flgure 4 but show~ the metallic layer 50 h~vlng been worn down duclnq p~olonged usage such that the distal end 52 o~ the ~etalllc layer 50 i6 dlsposed substant~ally tansentially relatlve to the web lOC. However, the co~pces~lble l~yer 54 du~ing usage ls compres~ed by the co~ting m~terial wlthln the wedge 38C such that ~ wedge of coa~lng mater~al 18 m~lntAlned upstrea~ of the metallic layer 50. By this means turbulence of the coating materlal ln the vicinity ~f the blade lBC iG minl~ized and streaklng o~ the reYultant coated web is inhibited. Furthe~more, bec~u~e the compre~slbl~e layee 54 ~ always co~.pre6~ed by the coatlng mnterial and not worn aw~y by the same, the life of the blade accord~ng to the present inventlon is subst~ntlAlly prolonged, Plguee6 6 and 7 show the blade 18D and 18~ according to the present lnventlon ~pplled to ~ shoet dwell coater and to a elooded nlp coater re6pectlvely for lnhlbitlng streaklng of coated web~.
13~
~g) In the Frefer~ed e~bodlment of the present inventlon, the hardness of the ~eb lOC i~ geeater th~n the hardneP~
of the co~pre~sible iayer 54 ~nd the cor.,pre3sible layet 54 18 fabrlc~ed from whl~e rubber ~o a~ to ovold marklng of the web ln the event of the rubber l~yer 54 comlng lnto cont~ct wlth the surface o~ the web lOC.
In operatlon of the coating apparatus accordlng to the pLe6ent lnvent~on, the we~ lOC 1~ mov~bly supported by rotatable b~cklng roll 12C cuch that the web lOC moves p~st the wedge-shaped space 38C between the web lOc and the bl~de l~C. Co~tlng material is smoothed and meterea onto the web lDC by the blAde lBC and even after prolonged usage of the blade laC the wedge-sh~ped space 38C ~
m~lntalned between the bl~de l~C and the web lOC ~o that turbulence of the coating 18 minlmized there~y lnhlbiting etreaklng Or the coatlng and prolonglng the llfe of the blade.
3y the prov'6ion of the blade according to the pre6ent lnventlon, homogeniz~tion of the coatlng mateeial 1~ lmproved thu4 lmproving the quality o~ the ee~ult~nt coatlng.
~ n an ~pplication of the blade accordlng to the present lnventlon, coating ~ates were lncrea~ed to 2,400m per mlnute before streaklng occurred whereas only 800m per mlnute were posslble be~ore streakln~ using prlor art blade~.
Claims (11)
1. A coating apparatus for applying a coating onto a web which is movably supported by a rotatable backing roll, said coating apparatus comprising:
a smoothing blade disposed adjacent to the web for smoothing and metering the coating onto the web;
said blade including:
a metallic layer having a distal end disposed adjacent to the web; and a compressible layer disposed contiguously and upstream relative to said metallic layer, said compressible layer having a distal end such that during use of the apparatus, when said distal end of said metallic layer wears away, said distal end of said compressible layer is compressed by the coating so that a wedge of the coating is disposed between the web and said blade, said wedge being defined by the web, said distal end of said metallic layer and said compressed distal end of said compressible layer thereby maintaining a smooth application of the coating on the web and prolonging the life of said blade.
a smoothing blade disposed adjacent to the web for smoothing and metering the coating onto the web;
said blade including:
a metallic layer having a distal end disposed adjacent to the web; and a compressible layer disposed contiguously and upstream relative to said metallic layer, said compressible layer having a distal end such that during use of the apparatus, when said distal end of said metallic layer wears away, said distal end of said compressible layer is compressed by the coating so that a wedge of the coating is disposed between the web and said blade, said wedge being defined by the web, said distal end of said metallic layer and said compressed distal end of said compressible layer thereby maintaining a smooth application of the coating on the web and prolonging the life of said blade.
2. A coating apparatus as set forth in claim 1, wherein said coating apparatus is a short dwell coater.
(11)
(11)
3. A coating apparatus as set forth in claim 1, wherein said coating apparatus is a flooded nip coater.
4. A coating apparatus as set forth in claim 1, wherein said metallic layer is fabricated from spring-steel plate.
5. A coating apparatus as set forth in claim 1, wherein said compressible layer is fabricated from a polymeric material.
6. A coating apparatus as set forth in claim 5, wherein said polymeric material is rubber.
7. A coating apparatus as set forth in claim 1, wherein the ratio of the thickness of said metallic layer to the thickness of said compressible layer is 1:2.
8. A coating apparatus as set forth in claim 1, wherein said metallic layer has a thickness within the range .3 to .7 millimeters.
9. A coating apparatus as set forth in claim 1, wherein said compressible layer has a thickness within the range .8 to 1.2 millimeters.
10. A coating apparatus as set forth in claim 1, wherein the hardness of the web is greater than the hardness of said compressible layer.
11. A coating apparatus as set forth in claim 1, wherein said compressible layer is fabricated from a material having a color substantially the same as the color of the coating so that in the event of said compressible layer coming into contact with the web, the web will not become marked by said compressible layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP96896/87 | 1987-06-24 | ||
| JP1987096896U JPS641778U (en) | 1987-06-24 | 1987-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1305855C true CA1305855C (en) | 1992-08-04 |
Family
ID=14177140
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000570459A Expired - Lifetime CA1305855C (en) | 1987-06-24 | 1988-06-27 | Coating apparatus having a blade with metallic and compressible layers |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS641778U (en) |
| KR (1) | KR890701229A (en) |
| AU (1) | AU2483188A (en) |
| CA (1) | CA1305855C (en) |
| WO (1) | WO1988010155A2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2785632B2 (en) * | 1993-02-19 | 1998-08-13 | 東レ株式会社 | Scraping blade and method of using the same |
| SE507926C2 (en) * | 1996-12-19 | 1998-07-27 | Btg Kaelle Inventing Ab | Coating sheet for coating a running track |
| SE511082C2 (en) * | 1996-12-20 | 1999-08-02 | Btg Eclepens Sa | coating Sheet |
| US6301461B1 (en) * | 1999-09-13 | 2001-10-09 | Cf Technologies | Doctor blade, toner cartridge using such a doctor blade and copying process |
| SE517846C2 (en) | 2001-02-16 | 2002-07-23 | Btg Eclepens Sa | Self-adjusting blades |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1206106A (en) * | 1966-09-02 | 1970-09-23 | English Clays Lovering Pochin | Improvements in or relating to the coating of sheet material |
| US3703019A (en) * | 1970-10-15 | 1972-11-21 | Norton Co | Surface conforming wear resistant doctor blade for rolls |
| DE2845036A1 (en) * | 1978-10-16 | 1980-04-17 | Jagenberg Werke Ag | DEVICE FOR CONTINUOUSLY APPLYING COATINGS OF CONSTANT THICKNESSES ON BOTH SIDES OF A MATERIAL RAIL |
| SE437681B (en) * | 1982-10-13 | 1985-03-11 | Inventing Ab | CREATIVE OR RABLE FOR CONTROLLABLE PAIRING AND EXTRAORDINATION OF APPLIANCES ON A CURRENT PAPER COAT |
-
1987
- 1987-06-24 JP JP1987096896U patent/JPS641778U/ja active Pending
-
1988
- 1988-06-24 AU AU24831/88A patent/AU2483188A/en not_active Abandoned
- 1988-06-24 WO PCT/US1988/002166 patent/WO1988010155A2/en unknown
- 1988-06-27 CA CA000570459A patent/CA1305855C/en not_active Expired - Lifetime
-
1989
- 1989-02-24 KR KR1019890700342A patent/KR890701229A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU2483188A (en) | 1989-01-19 |
| KR890701229A (en) | 1989-12-19 |
| WO1988010155A2 (en) | 1988-12-29 |
| JPS641778U (en) | 1989-01-06 |
| WO1988010155A3 (en) | 1989-02-09 |
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| MKEX | Expiry |