Paper: Lub whiteness ntawm daim ntawv yog qhov tseem ceeb rau vibrant luam xim. Cov ntawv zoo tshaj plaws qhia txog yuav luag tag nrho cov xim ntawm lub teeb, thaum daim ntawv muaj grey, dub, xiav, liab, lossis lwm yam tawm - xim absorbs qee qhov teeb meem teeb meem, cuam tshuam rau xim, ci, thiab saturation ntawm cov duab luam tawm, thaum kawg ua rau xim sib txawv. Qhov no sib npaug rau ntxiv lwm cov inks rau tus number case, ua rau tus number case tsis huv thiab muab qhov tsaus, av nkos, thiab tawm -xim xim.
Cov khoom tseem ceeb ntawm daim ntawv yog cellulose, sizing agents, thiab fillers. Qhov ntws ntawm tus cwj mem yog tus khi; tus number case pigments adheres rau daim ntawv nto los ntawm kev tsim thiab ziab ntawm ib zaj duab xis los ntawm cov binder. Ob daim ntawv thiab tus cwj mem yog feem ntau tsim los ntawm asymmetric molecules; Thaum lawv mus txog ib leeg, cov kev sib txuas sib txuas ua ke tso cai rau cov molecules ua raws li daim ntawv. Tam sim no, cov tuam txhab ntim khoom thiab kho kom zoo nkauj luam ntawv feem ntau yog siv cov ntawv dawb coated, ntoo pulp coated dawb cardboard, zoo tib yam linerboard, ntoo pulp coated linerboard, kraft ntawv, thiab dawb cardboard. Vim qhov sib txawv ntawm cov txheej txheem ntau lawm ntawm cov ntawv mills sib txawv, muaj qhov sib txawv tseem ceeb hauv qhov chaw whiteness thiab smoothness ntawm daim ntawv. Yog li ntawd, thaum lub sijhawm luam ntawv, cov kua dej tsawg heev -molecular- qhov hnyav ntawm tus number case binder raug yuam mus rau hauv qhov loj dua ntawm daim ntawv, thiab cov ntawv khi pib cais tawm ntawm tus number case. Thaum cov xim cov ntsiab lus ntawm tus number case yog siab, ntau me me capillaries tuaj yeem tsim nyob rau hauv cov yeeb yaj kiab number case. Cov capillaries ntau me me no muaj peev xwm khaws tau cov ntaub ntawv ntau dua li cov khoob fiber ntau ntawm daim ntawv. Thaum cov pigment ntsiab lus tsawg, tus number case adheres rau saum npoo ntawm daim ntawv, ua rau feem ntau ntawm cov binder nkag mus rau hauv daim ntawv lub pores, uas ua rau ib tug thinner number case zaj duab xis nyob rau hauv lub substrate, nthuav tawm pigment hais, thiab thaum kawg, ib tug tsawg vibrant xim.
Yog hais tias tus number case fountain thiab number case rollers tsis huv thaum daim ntawv thov number case, thiab sib xyaw nrog lwm cov xim xim, xim sib txawv yuav tshwm sim, thiab ua rau cov xim tsis muaj zog. Yog li ntawd, thaum hloov xim, nws yog ib qho tseem ceeb uas yuav tsum tau ua tib zoo ntxuav lub qhov dej ntawm tus number case, number case rollers, thiab water rollers, tshwj xeeb tshaj yog thaum hloov los ntawm tsaus mus rau lub teeb xim. Qhov kev coj ua ib txwm yog los ntxuav cov xim dub kom huv si, tom qab ntawd siv ib feem ntawm lub teeb number case los siv, sib tov nws sib npaug rau lub sijhawm, thiab tom qab ntawd ntxuav nws dua. Rau ob-xim thiab ntau- xim offset luam ntawv xovxwm, tshwj xeeb tshaj yog cov uas nyob rau sab sauv thiab sab qis sib koom ib lub tog raj kheej kheej kheej, yuav tsum tau saib xyuas ntxiv kom tsis txhob muaj xim sib xyaw. Kev sib xyaw xim yuav ua rau muaj kev sib txawv ntawm cov xim, uas ua rau cov xim du.
Additives: Kev luam ntawv offset feem ntau yog nyob ntawm tus number case -dej tshuav nyiaj li cas los ua kom tiav cov txheej txheem luam ntawv. Raws li tus txheej txheem hloov tus cwj mem, ink emulsification yog yam tsis muaj kev zam. Txawm li cas los xij, emulsification ntau dhau tuaj yeem ua rau cov xim luam tawm kom ploj mus thiab pom muaj hnub nyoog, txo cov xim vibrancy.
Offset luam ntawv kuj yuav tsum tau ntxiv ntau yam additives, xws li thinners thiab ziab khaub ncaws. Kev sib ntxiv ntawm cov additives ntau dhau tuaj yeem cuam tshuam cov xim vibrancy ntawm cov khoom luam tawm. Thinners muaj xws li cov xim dawb thiab cov roj dawb. Cov roj dawb feem ntau yog emulsion muaj li ntawm magnesium carbonate, stearic acid, number case thinner, thiab dej. Qhov no emulsion txhawb nqa tus lej emulsification, ua rau cov xim tsis zoo. Cov neeg ua kom qhuav yog cov tshuaj pleev xim hlau thiab tseem muaj zog emulsifiers. Ib qho me me ntawm tus neeg ua kom qhuav tuaj yeem ua kom ruaj khov number case emulsification, tab sis ntau ntxiv yuav ua rau tus number case emulsification hnyav.
Tsis tas li ntawd, rau cov ntaub ntawv luam tawm nrog thaj tsam me me ntawm cov ntawv nyeem thiab cov duab, tus lej ntawm tus lej tshiab ntxiv rau tus cwj mem rau hauv txhua lub voj voog kuj tseem tsawg dua. Yog li ntawd, tus cwj mem uas tseem nyob ntawm tus cwj mem rau lub sijhawm ntev yuav tsum tau sib tov, nyem thiab dov ntawm cov tshuaj dampening ob peb zaug, ua rau emulsification hnyav ntawm tus number case thiab ua rau cov xim dull.
