The　hard　roller　and　soft　roller　are　alternately　arranged　in　the　inking　system　of　offset　press.　The　ink　vibrator　is　a　hard　roller　which　transmits　the　motion　to　the　ink　distributing　roller.　In　order　to　analyze　the　motion　mechanism　of　the　ink　roller,　a　model　of　an　ink　distributing　roller　and　an　ink　vibrator　is　built　up　by　using　the　software　ANSYS.　After　the　simulation　of　the　motion,　the　force　on　the　contact　area　of　the　ink　distributing　roller　and　the　rotation　speed　of　both　rollers　are　analyzed.　The　result　is　that　the　ink　distributing　roller　rotates　with　tangential　force　on　the　contact　area　and　this　force　increases　together　with　the　rotation　speed.　When　the　two　rollers　rotate,　the　tangential　elastic　deformation　is　caused　by　the　tangential　force　on　contact　area,　and　the　radial　deformation　of　the　ink　distributing　roller　is　caused　by　the　pressure.　It　leads　to　a　relative　sliding　of　the　two　rollers,　which　is　mainly　influenced　by　the　rotation　speed　of　ink　vibrator　and　the　radial　deformation　of　ink　distributing　roller.　Meanwhile,　to　verify　the　accuracy　of　the　analysis,　the　rotation　speed　of　the　two　rollers　and　the　deformation　of　the　ink　distributing　roller　have　been　measured　on　a　printability　tester　and　then　compared　with　the　results　of　simulation.　The　analysis　of　the　motion　mechanism　is　very　important　to　the　study　of　printing　color　quality　control.