隨著我國(guó)節(jié)能減排理念的不斷推廣，鐳射壓印轉(zhuǎn)移工藝在煙包印刷領(lǐng)域的應(yīng)用越來(lái)越廣，但在煙包生產(chǎn)過(guò)程中也經(jīng)常會(huì)出現(xiàn)一些故障。文本中，筆者將結(jié)合日程工作中的一些經(jīng)驗(yàn)，介紹煙包鐳射壓印轉(zhuǎn)移工藝的常見(jiàn)問(wèn)題及解決方法，與業(yè)內(nèi)同行分享。
　　
　　鐳射壓印轉(zhuǎn)移工藝常見(jiàn)問(wèn)題解析
　　
　　1.出現(xiàn)皺膜現(xiàn)象
　　
　　鐳射轉(zhuǎn)移膜在一定張力下，通過(guò)壓合機(jī)構(gòu)將全息圖案轉(zhuǎn)移到印品表面，在這個(gè)過(guò)程中，鐳射轉(zhuǎn)移膜需要經(jīng)過(guò)多根導(dǎo)膜輥，容易出現(xiàn)皺膜現(xiàn)象。主要原因有以下兩點(diǎn)。
　　
　　（1）鐳射轉(zhuǎn)移膜收卷張力過(guò)大，使得膜卷兩端張力不一致，從而引起皺膜。此時(shí)，需要仔細(xì)調(diào)整出膜輥、導(dǎo)膜輥、阻尼輥的平衡，比較費(fèi)時(shí)。而且，當(dāng)下一次重復(fù)使用鐳射轉(zhuǎn)移膜時(shí)，張力不一致的方向會(huì)反過(guò)來(lái)，這就需要重新調(diào)整設(shè)備。常用的方法是在鐳射轉(zhuǎn)移膜收卷后立即復(fù)卷一次，以進(jìn)一步調(diào)整鐳射轉(zhuǎn)移膜的張力，并對(duì)其進(jìn)行散熱。
　　
　?。?）鐳射轉(zhuǎn)移膜本身沒(méi)有質(zhì)量問(wèn)題，不合壓不皺膜，一合壓就皺膜。這主要是由于鐳射轉(zhuǎn)移膜在壓印轉(zhuǎn)移時(shí)壓膜輥兩端的壓力不平衡所致。在這種情況下，需要調(diào)整壓膜輥兩端的氣缸壓力，即調(diào)節(jié)氣缸行程末端的壓合限位螺絲，因其位于墻板內(nèi)側(cè)，位置比較隱蔽，因此需要用塞尺進(jìn)行調(diào)節(jié)，注意及時(shí)鎖緊。有的鐳射壓印轉(zhuǎn)移設(shè)備壓膜輥兩端的氣缸壓力可以獨(dú)立調(diào)整，相對(duì)比較方便。
　　
　?。?）鐳射轉(zhuǎn)移膜在各導(dǎo)膜輥處的張力不平衡，造成走膜速度和壓印速度不一致，從而引起皺膜。
　　
　　2.全息圖案出現(xiàn)針孔、白點(diǎn)現(xiàn)象
　　
　　這種現(xiàn)象主要表現(xiàn)為針孔、白點(diǎn)位置只有UV光油沒(méi)有全息圖案，或既沒(méi)有UV光油也沒(méi)有全息圖案。具體可分為以下幾種情況。
　　
　?。?）針孔、白點(diǎn)的位置與形狀比較固定。主要原因：①上光版或網(wǎng)紋輥表面有凹坑，造成印品表面對(duì)應(yīng)位置沒(méi)有UV光油，自然就沒(méi)有全息圖案；②當(dāng)使用帶光標(biāo)的單版避版縫鐳射轉(zhuǎn)移膜，且UV光油涂布沒(méi)有問(wèn)題時(shí)，如果仍然出現(xiàn)這種情況，可能是鐳射轉(zhuǎn)移膜表面有瑕疵，如鐳射轉(zhuǎn)移膜每個(gè)重復(fù)周長(zhǎng)對(duì)應(yīng)的位置上本來(lái)就沒(méi)有全息圖案，壓印轉(zhuǎn)移后自然就會(huì)產(chǎn)生針孔、白點(diǎn)。
　　
　?。?）針孔、白點(diǎn)的位置與形狀不固定。主要原因：①鐳射轉(zhuǎn)移膜質(zhì)量不穩(wěn)定，在壓印轉(zhuǎn)移時(shí)容易黏掉UV光油，，如使用回收膜制成的OPP鐳射轉(zhuǎn)移膜就容易出現(xiàn)此類問(wèn)題；②UV光油的助劑添加不當(dāng)，或蠟質(zhì)、硅油、膏類等物質(zhì)添加過(guò)量所致，如有的UV光油生產(chǎn)廠家因?yàn)檫x用的單體不當(dāng)，為減少UV光油的泡沫，添加了過(guò)量的消泡劑，造成壓印轉(zhuǎn)移時(shí)UV光油無(wú)法充分進(jìn)入鐳射轉(zhuǎn)移膜的網(wǎng)穴；③個(gè)別煙包采用UV膠印工藝印刷大面積實(shí)地或多色疊印，由于UV油墨固含量較高且瞬間固化，導(dǎo)致印品表面的墨膜不平整，為增強(qiáng)鐳射壓印轉(zhuǎn)移效果，很多煙包印刷企業(yè)采用了“印刷油墨表面滿版涂布底油+鐳射壓印轉(zhuǎn)移”的工藝，但是由于底油中可能含有過(guò)量的硅油、流平劑等，造成底油在印刷油墨表面的附著力不佳，部分底油在剝離時(shí)被鐳射轉(zhuǎn)移膜帶走（可看到在鐳射轉(zhuǎn)移膜上有點(diǎn)狀的底油痕跡），從而使得鐳射壓印轉(zhuǎn)移不*，印品表面出現(xiàn)白點(diǎn)；④UV燈使用時(shí)間過(guò)長(zhǎng)，有效功率不足，使得UV光油不能*固化，部分UV光油在剝離時(shí)被鐳射轉(zhuǎn)移膜帶走，此時(shí)應(yīng)及時(shí)更換UV燈，一般國(guó)產(chǎn)UV燈的使用壽命約為1000~1500小時(shí)；⑤因皺膜引起鐳射壓印轉(zhuǎn)移不*，使得印品表面產(chǎn)生大面積白點(diǎn)。
　　
　?。?）印品拖梢中部、走紙方向上出現(xiàn)條狀的大面積白點(diǎn)或鐳射壓印轉(zhuǎn)移不*的現(xiàn)象。這主要是由于承印材料嚴(yán)重變形所致。如使用低檔灰底白卡紙時(shí)，由于車間溫濕度的變化，紙張因吸濕和放濕而產(chǎn)生“荷葉邊”，導(dǎo)致壓印轉(zhuǎn)移時(shí)紙張與鐳射轉(zhuǎn)移膜之間的空氣不能排盡。解決方法：平衡生產(chǎn)進(jìn)度，保護(hù)承印材料，控制車間溫濕度。
　　
　　（4）印品表面局部出現(xiàn)針孔、白點(diǎn)，尤其是印品橫向上，鐳射壓印轉(zhuǎn)移效果一邊好，一邊差。主要原因有：①壓印輥老化、硬度太低或磨損嚴(yán)重，需要重新車磨舊輥或更新新輥，向原廠購(gòu)買新輥，且一定要注意其橡膠層應(yīng)為耐紫外線膠型，此外，為延緩壓印輥老化，在設(shè)備保養(yǎng)時(shí)，切忌勿使用酯類溶劑擦洗壓膜輥（容易造成溶劑殘留），建議使用乙醇擦洗；②如果上光單位采用的是柔性版上光方式，就可能是由于網(wǎng)紋輥壓力沒(méi)有調(diào)好所致，此時(shí)需要重新調(diào)整印刷壓力及網(wǎng)紋輥對(duì)印刷的壓力；③如果鐳射壓印轉(zhuǎn)移設(shè)備流平段有雜物（如紙皮等），且傳送帶左右張力和速度不一致時(shí)，會(huì)造成紙張?jiān)阼D射壓印轉(zhuǎn)移設(shè)備流平段歪斜，使得壓印轉(zhuǎn)移時(shí)紙張與鐳射轉(zhuǎn)移膜之間的空氣不能排盡，從而造成上述問(wèn)題。
　　
　?。?）采用同一種UV光油進(jìn)行鐳射壓印轉(zhuǎn)移，夏季生產(chǎn)時(shí)不出現(xiàn)白點(diǎn)，冬季生產(chǎn)時(shí)卻出現(xiàn)白點(diǎn)。這種情況主要出現(xiàn)在北方地區(qū)，主要是由于環(huán)境溫度過(guò)低導(dǎo)致UV光油中某種材料（如光敏劑、流平劑等）產(chǎn)生結(jié)晶。如某流平劑的結(jié)晶溫度在10°左右，如果低于10°為半固態(tài)，其就不再為液態(tài)，這將嚴(yán)重影響鐳射壓印轉(zhuǎn)移的正常進(jìn)行。解決方法：將UV光油加熱至40°～50°后再使用；使用耐低溫的UV光油；調(diào)整UV光油的配方。
　　
　　（6）鐳射壓印轉(zhuǎn)移開(kāi)始階段出現(xiàn)的針孔、白點(diǎn)較少，后階段出現(xiàn)的針孔、白點(diǎn)越來(lái)越多。這多半是由灰塵引起的。因此，在設(shè)備保養(yǎng)時(shí)，應(yīng)注意檢查導(dǎo)膜輥上是否有灰塵，并保持勤擦洗。有條件的煙包印刷企業(yè)對(duì)車間進(jìn)行防塵隔離處理，以保持車間環(huán)境潔凈。如果車間內(nèi)沒(méi)有防塵隔離設(shè)施，生產(chǎn)時(shí)應(yīng)注意關(guān)好車間門窗，每班次至少清洗4次導(dǎo)膜輥，一般在更換鐳射轉(zhuǎn)移膜時(shí)進(jìn)行。
　　
　　綜上所述，對(duì)針孔、白點(diǎn)問(wèn)題的控制要點(diǎn)可以概括為“四平”、“四凈”：“四平”是指設(shè)備安裝時(shí)保持設(shè)備前后段水平一致，壓印轉(zhuǎn)移時(shí)保持鐳射轉(zhuǎn)移膜平整，保持承印材料平整，選擇流平性好的UV光油；“四凈”是指保持上光版（柔性版或凹版）潔凈，保證UV光油過(guò)濾干凈，保持導(dǎo)膜輥潔凈，保持車間環(huán)境潔凈。
　　
　　3.鐳射壓印轉(zhuǎn)移效果差（如全息圖案表面粗糙、光澤度差）
　　
　　主要原因：①UV光油涂布量不足（可能是網(wǎng)紋輥線數(shù)過(guò)高，網(wǎng)穴深度不夠所致）；②UV光油的黏度太低；③為降低成本，在UV光油中添加了過(guò)量的溶劑（如酒精），或溶劑使用不當(dāng)；④鐳射轉(zhuǎn)移膜的使用次數(shù)太多，其上的網(wǎng)穴不完整，不能形成良好的鐳射效果，造成全息圖案光澤度差；⑤UV光油的低溫下產(chǎn)生結(jié)晶。
　　
　　4.全息圖案發(fā)黃變色
　　
　　經(jīng)過(guò)鐳射壓印轉(zhuǎn)移后，煙包表面的全息圖案出現(xiàn)發(fā)黃變色現(xiàn)象（俗稱“黃變”）。這種情況特別容易出現(xiàn)在配置有高功率UV燈的高速鐳射壓印轉(zhuǎn)移設(shè)備上。這主要是由于UV光油配方中的光敏劑選擇不當(dāng)，如選用了成本較低的Irgacure651光敏劑。解決方法：要求UV光油供應(yīng)商更換光敏劑（如Irgacure184、Darocur1173等）；適當(dāng)調(diào)低UV燈的功率。
　　
　　5.全息圖案表面產(chǎn)生顆粒狀凸起現(xiàn)象
　　
　　肉眼一般無(wú)法觀察到這種現(xiàn)象，只能借助10倍以上的放大鏡才能觀察到。其實(shí)，造成全息圖案表面產(chǎn)生顆粒狀凸起現(xiàn)象的物質(zhì)是灰塵或幽默顆粒。如果是膠印產(chǎn)品，主要原因是油墨印刷不平整、油墨顆粒粗、墨層過(guò)厚。建議在調(diào)墨時(shí)盡量將色相調(diào)深一些，或印刷后在印品表面涂布一層UV底油。如果是凹印產(chǎn)品，可能與紙張橫切時(shí)產(chǎn)生的粉塵有關(guān)。除了及時(shí)更換橫切刀之外，建議在拼版時(shí)注意拼版方向，將印品叼口拼在卷筒紙走紙方向前方，在橫切時(shí)則以印刷叼口為入刀口，并調(diào)整上下橫切刀的間隙。此外，對(duì)橫切后的單張紙印品的拖梢切一刀（如1mm），將毛邊切掉，從而大大降低粉塵。
　　
　　6.先燙印后鐳射壓印轉(zhuǎn)移時(shí)，電化鋁表面的UV光油附著力不佳
　　
　　這種現(xiàn)象主要表現(xiàn)在用指甲劃過(guò)或用3M膠帶粘貼燙印圖案表面時(shí)，UV光油脫落。主要原因：①UV光油與電化鋁的匹配性差；②燙印工序與鐳射壓印轉(zhuǎn)移工序之間的周轉(zhuǎn)時(shí)間過(guò)長(zhǎng)，燙印后電化鋁表面的涂層發(fā)生氧化。
　　
　　7.先燙印后鐳射壓印轉(zhuǎn)移時(shí)，燙印邊緣“飛金”多
　　
　　主要原因：①電化鋁邊緣燙印不實(shí)；②電化鋁與UV光油不匹配，UV光油對(duì)電化鋁有溶解作用。
　　
　　解決方法：①調(diào)整電化鋁的類型；②對(duì)電化鋁與UV光油的匹配性進(jìn)行測(cè)試。簡(jiǎn)易的測(cè)試方法是選擇2種鐳射壓印轉(zhuǎn)移效果相差不大的UV光油，將長(zhǎng)度和寬度相同的電化鋁放入倒有UV光油的紙杯中，觀察并比較電化鋁在2種UV光油中的溶解時(shí)間，優(yōu)先選擇溶解時(shí)間長(zhǎng)的UV光油做進(jìn)一步測(cè)試。
　　
　　8.全息圖案表面發(fā)澀，上機(jī)包裝不順暢
　　
　　主要原因：UV光油的固化速度與UV燈功率、生產(chǎn)速度不匹配，導(dǎo)致鐳射轉(zhuǎn)移膜在壓印轉(zhuǎn)移后剝離情況不佳；UV光油中的助劑添加不當(dāng)，如流平劑含量過(guò)少，防水霧劑含量過(guò)多。
　　
　　要想確定全息圖案表面的發(fā)澀程度是否不利于煙包上機(jī)包裝，可利用摩擦系數(shù)儀測(cè)試其表面的摩擦系數(shù)的方法來(lái)判斷。特別注意的是，有時(shí)全息圖案表面的手感已經(jīng)很滑，但煙包上機(jī)包裝時(shí)還是不夠順暢，這主要與UV光油配方中的樹(shù)脂種類（如聚氨酯材料）和添加的流平劑種類有關(guān)，應(yīng)要求UV光油供應(yīng)商配合解決。
　　
　　9.上機(jī)包裝時(shí)，煙包折角處的全息圖案易被蹭掉
　　
　　當(dāng)煙包表面涂油UV底油時(shí)，這種情況特別容易出現(xiàn)，因此須調(diào)整UV底油和UV光油的匹配性。如果使用水性底油，注意不能添加蠟質(zhì)、硅油等助劑。如果是凹印產(chǎn)品，建議使用溶劑型UV底油，或使用UV凹印沖淡劑、透明墨、調(diào)金油等作為UV底油，因?yàn)槠渑cUV光油的匹配性較好。如果是膠印產(chǎn)品，溶劑型UV底油反而不一定合適，因此需要仔細(xì)測(cè)試UV底油與UV光油的匹配性，墨層較薄的產(chǎn)品不需要涂布UV底油。
　　
　　Withtheconceptofenergy-savingandemission-reductioncontinuallypopularizedinChina,theHologramImagesTransferringprocessismoreandmorewidelyappliedincigarettepackageprinting,however,someproblemsandmalfunctionsmayfrequentlyoccurontheproductionlineofcigarettepackage.Inthisthesis,theproblemsofcommonoccurrenceintheHologramImagesTransferringprocessandthecorrespondingsolutionsaretobeintroducedbytheAuthor,whosepracticalworkingexperiencesareintegratedintheintroductiontoo,soastoprovidesomevaluableinformationforsharingwithcolleaguesinthesametrade.
　　
　　AnAnalysis
　　
　　On
　　
　　TheProblemsofCommonOccurrence
　　
　　IntheProcessof
　　
　　HologramImagesTransferring
　　
　　Author:JiaoJieming
　　
　　BengbuJinHuangshanMountainAobanPrintingLimitedCompany
　　
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　　1.FilmCrinkling
　　
　　Undercertainstrainstrength,withtheaidofpressingdevice,HolographicTransferringFilmcantransferhologrampatternsontothesurfaceofpressworksheet.Duringthewholeprocess,HolographicTransferringFilmmustgothroughmorethanonefilm-guidingroller,sothatitisliabletooccurfilmcrinkling.Themaincausesare:
　　
　?。?）TherewindingtensionofHolographicTransferringFilmistoolarge,makingthetensiononthetwoendsofthefilmrolldifferentfromeachotherandthenthefilmcrinkled.Forthat,itisneededtoadjusttheuniformitiesbetweenfilmoutlet-roller,guiding-rolleranddamping-roller,whichisatime-consumingjob.Furthermore,whenusetheHolographicTransferringFilmforanexttime,theoperationdirectionsoncewithdifferenttensionswillreverse,andthenthesystemhastobereset.Astothis,thenormalsolutionistorewindingtheHolographicTransferringFilmrollonceagainafteritsrewinding,whichcanregulatethetension,andhelptoheat-dissipate.
　　
　?。?）ThereisnoqualityfaultintheHolographicTransferringFilm,andwithoutembossingpress,filmcrinklingneveroccurs,butoncetheFilmgetsanembossingpress,itcrinkles.Theproblemmainlycausedbythedifferentpressuresonthetwoendsoffilm-pressroller.Inthatcase,thepressureinthecylinderateachendofthefilm-pressrollerneedtoberegulate,thatistoreadjustthelimitingscrewsatthestrokeendofthecylinder,whichlocatedatinnersideofwallplate.Duetoitshard-to-touchlocationpoint,theadjustingshouldbecarryoutwithafeelergaugeanddon’tforgettotimelytightenittothelockingpoint.However,asforsomeHologramimagesTransferringEquipments,thecylinders’pressuresonfilm-pressrollers’endscanbeseparayreadjust,soitisveryconvenienttoregulate.
　　
　　（3）IfthetensiononHolographicTransferringFilmattheguiding-rollersisnotthesame,thefilmdeliveringspeedandtransferringspeedwillnotbeevenandthenwillmakefilmcrinkled.
　　
　　2.Pinholes&whiteflakesonhologrampattern
　　
　　Atthepositionsofthesepinholes&whiteflakes,thereareonlyUVvarnishingbutnohologrampatternappears,orneitherUVvarnishingnorhologrampatternappears.Specificcasesasfollows:
　　
　?。?）Pinholeorwhiteflakewithfixedshapeandfixeddistributingposition.Maincauses:1thereisoneormorepitsonthesurfaceofcoatingplateoraniloxroller,sothatonthetransferredsheets’surfacethereisnoUVvarnishingatthepositionresponsivetothepit,thehologrampatterisofcoursemissing.2Ifseam-avoidmarkedHolographicTransferringFilmisadoptedandthespreadcoatingofUVvarnishingisnoproblem,theoccurrenceoftheabovementionedcasemayoriginateformtheflawsonthesurfaceofHolographicTransferringFilm,forexample,thereisnohologrampatternattheresponsivepositionofeachrepeatedperimeteroftheHolographicTransferringFilm,ofcoursePinholeorwhiteflakewillemergeaftertransferring.
　　
　?。?）Pinholeorwhiteflakewithunfixedshapeandunfixeddistributingposition.Maincauses:1thequalityoftheHolographicTransferringFilmisnotsteadyandliabletostickoffUVvarnishingduringtransferring,forexample,OPPHolographicTransferringFilmproducedwithrecycledfilmismoreliabletosuchproblem;2additionagentforUVvarnishingwasnotproperlyadded,ortheamountofaddedwax,siliconoil,pastyelementorothersubstanceswastoolarge,makingUVvarnishingcannotsufficientlyenterintothemeshholeofHolographicTransferringFilm;3inthetransferringofsomecigarettepackages,UVoffsetprintinginlargeareaisadoptedandneedtoimplementmulti-coloroverprinting,duetothehighcontentofUVprintinginkanditspropertyofquicksolidification,theink-coatonthesurfaceoftransferredsheetsisoftennotsmooth.Inordertoreinforcethehologramtransferringeffect,manycompanyengagedincigarettepackageprintingadopttheprocessof“printinginksurfacecoatedwithwholeplatebaseoilcoat+hologramimagestransferring”,However,inthebaseoilcoat,thecontentofsiliconoilorflattingagentmaybetoohighthenreducetheadhesivepowerofthebaseoilcoatonthesurfaceofprintingoil,resultingthatsomepeelingoffbaseoilcoatbeentrappedbyHolographicTransferringFilm（baseoilcoatflakescanbeseenonHolographicTransferringFilm）,thenmakethetransferringinadequateandwhiteflakesemergeonthetransferredsheets;4theworkingtimeofUVlampistoolong,andtheeffectivepowerofthelampisinsufficient,whichcausetheUVvarnishingcannotsolidifyadequayandsomepeelingoffUVvarnishingentrappedbyHolographicTransferringFilm,insuchacase,theUVlampmustbereplacedassoonaspossible.TheperformancelifeofordinarydomesticUVlampisabout100-1500h;5filmcrinklingcausesinadequatetransferring,resultingthatwhitesflakesemergesinlargearea.
　　
　?。?）Inthemiddleoftransferredsheets’tailendandinthedirectionofpaperdelivery,largeareaofwhiteflakesstripesorinadequatetransferringemerged.Themaincauseforthatisseveredeformationofprintingstock.Iflow-gradewhitepaperboardwithgreygroundwasused,duetothetemperaturefluctuationinworkshop,“lotus-leaf-edge”wouldappearonthepaperboardbecauseofmoistureabsorptionanddisabsorption,whichwouldimpedetheexcludingoftheairbetweenpaperboardandHolographicTransferringFilmduringtransferringoperation.Solution:arrangethemanufacturescheduleappropriay,payattentiontotheprotectionofprintingstockandthecontrolsoftemperatureandhumidityinworkshop.
　　
　?。?）Pinholesorwhiteflakesemergeonpartareaofthesurfaceoftransferredsheets,especiallyonthetransverseareaofthearticle,thetransferringeffectononesideisgoodwhileontheothersideisnotgood.Maincausesinclude:1thepressrubberrollerwasagedanddegraded,itshardnesswasreducedanditsbodywasheavilyworn.Theoldrollerneedstobereconditionedorreplacedwithanewone.Itisrecommendedtobuyanewrollerformtheoriginalmanufacturer,andmoreattentionshouldbepaidtotheroller’rubberlayer,whichmustbemadeofUV-resistancerubber.Furthermore,inordertodelaytheagingofpressrubberroller,itisrecommendedtouseethanoltocleantheroller,andneveruseesterssolvent（whichisliabletoproduceresidue）ascleanagentinthemaintenanceoftheroller;2Ifflexographicplatewasadoptedinthecoatingunit,andifthepressureofanilox-rollerwasnotadjustedproperly,abovementionedproblemmightbecaused,insuchacase,transferringpressureandanilox-roller’pressureonprintingplateshouldbereadjusted;3ifthereareforeignsubstances（e.g.paperpiece）heldupintheLevelingSectionoftheHologramImagesTransferringEquipment,andthestrainstrengthsandspeedsontheconveyingbelt’sleftandrightsidesarenotthesamewitheachother,thepaperinLevelingSectionwilldeflectandnotlocateatrightplace,whichcanimpedetheexcludingoftheairbetweenpaperandHolographicTransferringFilmduringtransferringoperation,andthencausetheabovementionedproblem.
　　
　?。?）WhenadoptingacertainUVvarnishinginHologramImagesTransferring,nowhiteflakesemergeintheproductioninsummer,butintheproductioninwinter,eventhesameUVvarnishingisused,whiteflakesemergenevertheless.SuchaproblemmainlytakesplaceinnorthernChina,andthecrystallizationofsomeaagent（e.g.photosensitizer,flattingagent）inUVvarnishingduetothelowambienttemperatureisthemaincause.Ifthecrystallizationtemperatureofflattingagentisat10℃,oncebelow10℃,theagentwillbeinsemi-solidstateinsteadofliquidstate,andthenhasanegativeinfluenceontheregularoperationofhologramimagestransferring.Solution:heatingtheUVvarnishingtothetemperatureof40℃-50℃beforeputtingitintoservice;onlyadoptinglow-temperature-resistanceUVvarnishing;andrevisingtherecipeofvarnishingtoimprovetheeffect.
　　
　?。?）Attheinitialstageofhologramimagestransferringoperation,onlyafewofPinholesorwhiteflakesemerge,however,atlaterstages,moreandmorePinholesorwhiteflakeswillemergeandthechiefcauseisdust.Therefore,duringequipmentmaintenance,pleasecarefullycheckifthereisanydustheldupontheguiding-roller,andregularandfrequentwipingandcleaningisalsorequired.Itishighlyrecommendedforprintingenterpriseswithconvenientconditionstoequipworkshopwithdustproofinstallationstokeeptheworkshopno-dustandclean.Ifnodustproofinstallationcanbeequippedinworkshop,thedoorofworkshopshouldbecarefullyclosed,andtheguidingrollershouldbecleanfour（4）timesatleastinoneworkingshift,normallydothecleaningatthesametimeofHolographicTransferringFilmreplacing.
　　
　　Onthewhole,thekeypointstocopewithpinholesandwhiteflakescanbesummarizedas“fourlevels”and“fourcleans”;,fourlevels:ensuretheforwardpartandrearwardpartkeeplevelwitheachotherwhensettinguptheequipment,keepHolographicTransferringFilmlevelandflatduringtransferringoperation,keepprintingstocklevelandflat,andonlyselectUVvarnishingwithgoodlevel-ability;fourcleans:keeptheplate（flexographicplateorgravureplate）clean,ensureUVvarnishingbecleanlyfiltered,keepguiding-rollercleanandneat,andkeepworkshopclean.
　　
　　3.Undesirablehologramimagestransferringeffect（e.g.roughhologrampatternsurface,badsurfacegloss）
　　
　　Maincauses:1theamountofUVvarnishingisinadequate（causes:thenumberofanilox-rollerlinesistoohigh,orthedepthofmeshholeisnotenough）;2theviscosityofvarnishingistoolow;3toomuchsolvent（e.g.alcohol）wasaddedintothecoatingforthepurposeofcostreducing,orusethesolventimproperly;4theHolographicTransferringFilmhadbeenusedfortoomanytimesandthemeshholesonitturnedfragmentary,sothatthelaserexposureeffectisnotverygoodthenhasanegativeinfluenceonthesurfaceglossofthehologrampattern;5underlowambienttemperature,theUVvarnishinghadturnedcrystallized.
　　
　　4.Hologrampatternappearinginchanged,yellowishcolor
　　
　　Hologrampatternappearsinchanged,yellowishcolorafterembossingandtransferringoperation.（commonlyreferredtoas“changingyellow”）.SuchaproblemisespeciallyliabletotakeplaceonHigh-speedHologramImagesTransferringEquipmentwithhighpowerUVlamp.ThatismainlybecausethephotosencitizerintherecipeoftheUVvarnishingwasnotrightlyselected,forexample,thelowprice–lowperformanceIrgacure651wasselected.Solution:requestthesupplieroftheUVglazingoiltoreplacethephotosencitizerwithdesirableones（e.g.Irgacure184,Darocur1173）;reducethepoweroftheUVlampproperly.
　　
　　5.Granularpocksonthesurfaceofhologrampattern
　　
　　Suchanappearancenormallycannotbeseenbynakedeyewithoutthehelpof10×magnifier.Infact,itisdustandprintinkparticlesthatcausesuchaproblem.
　　
　　Asforoffsetprinting,themaincauseisthattheprintinginkwasnotprocesseduptoenoughsmoothness,theink’sparticlesarenotfineandtheink-coatistoothick.Itisrecommendedtomakethecolorhueofinkasdarkaspossibleinthepreparationofprintingink,orapplyaUVvarnishingcoatontheprintedarticleafteroperation.
　　
　　Asforgravureprinting,suchaproblemmaybecausedbythedustcreatedincross-cuttingofpapers.Besidesreplacingthecross-cutter,moreattentionshouldbepaidtothedirectionofpatch-up,thegripperedgefortransferredsheetsshouldbelocatedaheadalongthepaperdeliverydirectionoftheweb,andthenthegripperedgewillbetakenascuttinginletofpaper’scross-cutting,thegapbetweenupperandlowercross-cuttersshouldbereadjustedtoo.Furthermore,theendtailofsinglepieceofarticleshouldgetanadditionalcut（e.g.acutof1mm）,sothattheroughedgebecutoffandtheamountofdustbereduced.
　　
　　6.Asfortransferringafterfoilstamping,UVvanishing’sadhesiveonaluminumsurfacenotverygood
　　
　　Afingernail-scratch,orapplyinga3Msealingtapeonthesurfaceoffoilstampedpattern,canmaketheUVvarnishingscaledoff.Maincauses:1thecompatibilitybetweenUVvarnishingandaluminumisundesirable.2thetimeintervalbetweenfoilstampingandtransferringwastoolong,thecoatofaluminumsurfacehadbeenoxidizedthroughsuchalongtime.
　　
　　7.Asfortransferringafterfoilstamping,toomuch“foil-splashing”onfoilstampingpatterns’edge
　　
　　Maincauses:1thealuminumedgehadnotbeenfoilstampedsturdily;2thealuminumisnotcompatiblewiththeUVvarnishing,andthevarnishinghassomedissolutioneffectonthealuminum.
　　
　　Solution:1re-selectthealuminumtobeused;2testthecompatibilitybetweenaluminumandUVvarnishing.Asimpletestmethodistoselect2kindsofUVcoatingswithsimilartransferringeffect,thenputaluminumsampleswithsamelengthandwidthintothepapercupsfilledwith2kindsofUVvarnishing,now,examineandcomparethetimelengthforthedissolutionofeachaluminumsampleinoneofthe2papercups,then,theUVvarnishingwithlongerdissolutiontimeshouldbetakenforfurthertest.
　　
　　8.Thehologrampattern’ssurfaceisunsmoothandnotsuitableforpackagingmachineprocessing
　　
　　Maincauses:thesolidificationspeedofUVvarnishingisnotcompatiblewiththepowerofUVlampandtheproductionspeed,leadingtheHologramTransferringFilmintoapoorconditionafterhologramimagestransferringoperation;additionagentsforUVvarnishingwerenotproperlyadded,forexample,theamountofflattingagentaddedwastoolittle,whiletheamountofantifoggingagentaddedwastoomuch.
　　
　　Inordertodeterminewhethertheun-smoothnessofhologrampattern’ssurfaceissuitableforpackagingmachineprocessingornot,africtionmetercanbeused.Pleasenote:sometimeseventhehandfeelofthehologrampatternissmooth,itisstillnotgoodforpackagingmachineprocessing,whichdependingonthetypeofresin（e.g.polyurethane）intherecipeofUVvarnishing,andthetypeofflattingagentaddedinthecoating,sothesupplieroftheUVvarnishingarerequiredtocollaboratetosolutetheproblem.
　　
　　9.Duringpackagingmachineprocessing,thehologrampatternonthecornersofacigarettecaseiseasytoberubbedoff
　　
　　SuchaproblemisliabletotakeplaceespeciallywhenthereisUVbasecoatingonthesurfaceofcigarettecase,therefore,thecompatibilitybetweenUVbasecoatingandUVvarnishingisofgreatimportance.Ifaqueousbasecoatingistobeused,pleasedon’tusewaxorsiliconoilasadditionagent.Asforgravureprinting,solvent-bornetypebaseoilisrecommendable,andgravureprintingthinner,PlastisolprintinginkorgoldvanishcanalsobeusedbecauseoftheirgoodcompatibilitywithUVvarnishing.Asforoffsetprinting,onthecontrary,solvent-bornetypebasecoatingisnotrecommendable,therefore,thecompatibilitybetweenUVbasecoatingandUVvarnishingshouldbecarefullytested,andforproduct（article）withathinnerinkcoat,noUVbasecoatingspreadingisneeded.