Let’s Watch How It Works …• http://www.youtube.com/watch?v=0gEEaFT5z84&list=PL9EC96E5ADAC7FCF1• http://www.youtube.com/watch?v=XUlBueqStg4
9 types of printingOffset lithographyEngraving - thinkfine stationeryThermography -raised printing, usedin stationeryReprographics -copying andduplicatingDigital printing -limited now, but thetechnology isexplodingLetterpress - theoriginal guttenbergprocess (hardlydone anymore)Screen - used for t-shirts and billboardsFlexography -usually used onpackaging, such ascan labelsGravure - used forhuge runs ofmagazines anddirect-mail catalogs
Offset printing.• Also known as offsetlithography.• Its relativelyinexpensive and printsvery well.• What is the off-setprinter based on?• That water and oil repeleach other.http://www.youtube.com/watch?v=ss5soAuolks&list=PL9EC96E5ADAC7FCF1
Offset Printing• Plates are used to holdthe ink and waterprevents the ink fromrunning onto the spaceswhere ink should not be.• It is transferred to arubber blanket.• The image is then off-setfrom the blanket to thepaper.• Why do they use a rubberblanket instead of justprinting to the paper.
Flexography1.Used to print on flexiblematerial such as plasticbags, which would betorn apart in an off setprinter.2.Uses soft plate andprints plate to surface.3.The ink is relatively thinand dries quickly onnon-porous materialssuch as plastic and foil.
Letterpress1.Originated in Asia usingindividual letters made ofclay.2.Gutenberg developed theprocess in Germany usingcharacters molded fromlead. (Where the leadingcame from)3.Characters on the plate arehigher than the materialsurrounding them.4.Rubber stamps work on thesame principle.
Engraving1.Images are cut into the metal platerather than raised above the plate likeletterpress.2.The surface of the plate is coveredwith ink, then wiped clean, leavingthe engravings full of ink.3.The press then forces paper into theinked recesses, transferring the imageto the surface of the paper.4.Engraved paper feels slightly indentedbehind its image areas.
Thermography or raised printing1.Can be produced more quicklythen engraving and to theuntrained eye looks and feelssimilar.2.Thermography is a four-stageprocess that begins with offsetprinting using inks that dry slowly.3.Next the sheets are sprayed with afine resin powder which sticks tothe wet ink4.Then a vacuum unit collects thepowder that didn’t stick to the ink5.Finally a heating unit melts theremaining powder into the ink.The powder swells as it melts, sothe printing rises above thesurface of the paper
Laser printer• Cleaning-The drum is cleaned ofany residual toner and electricalcharge.• Conditioning-The drum (which isas wide as a sheet of paper) isconditioned to contain a highelectrical charge.• Writing-A laser beam dischargesa lower charge to only thoseplaces where toner is to go.• Developing-Toner is placed onthe drum where the charge hasbeen reduced.• Transferring-A strong electricalcharge draws the toner off thedrum onto the paper.• Fusing- Heat and pressure fusethe toner to the paper.