Vibrationsofoffsetprintingpressesareseriousproblem,whichcausemanydifficultieswhileprintingandimpairqualityoftheprints.Thebiggestproblemliesinconstructionofprintingunit.Itmainlyconsistsofthreecylinders,buttwoofthemareinadirectcontactgenerateundesiredvibrations.Constructionofthecylindersmakesthatstiffnessoftheunitvariesperiodicallywhileprinting.Inthispapermodelofoffsetprintingunitispresented.Themodelisdescribedbythesystemoftwoparametricdifferentialequations.Computersimulationsofthebehaviouroftheprintingunithavebeenperformed.Conditionsinwhichparametricresonanceappearsarealsoappointedhere.
