Patent ID: 8256344
Filing Date: 2012-09-04
Classification: B41F

Abstract:
1. A method for controlling rollers in a dampening agent application roller train of a printing unit including: providing a source of a dampening agent; providing a first roller having a first roller surface adapted for taking up a dampening agent from said source of dampening agent; providing a second roller having a second roller surface contacting said first roller surface and receiving said dampening agent directly from said first roller surface; providing a forme cylinder having a forme cylinder surface speed of rotation; providing a forme cylinder drive motor; using said forme cylinder drive motor and rotating said forme cylinder at said forme cylinder surface speed of rotation; including said first and said second rollers in a roller train usable for conveying said dampening agent to said forme cylinder; providing a first roller drive motor for driving said first roller; rotating said first roller at a first roller surface speed using said first roller drive motor; providing said first roller surface speed at less than 2 m/s; providing a second roller drive motor for driving said second roller at a second roller surface speed independently of said first roller; controlling each of said first roller drive motor, said second roller drive motor and said forme cylinder drive motor independently of each other; rotating said second roller at said second roller surface speed, different from said first roller surface speed using said second roller drive motor; selecting said second roller surface speed being greater than said first roller surface speed; selecting both said first roller surface speed and said second roller surface speed being less than said forme cylinder surface speed of rotation; setting both of said first roller surface speed and said second roller surface speed as a function of said forme cylinder surface speed; selecting a slippage between said first roller surface and said second roller surface by said controlling of each of said first roller drive motor and said second roller drive motor independently, said selected slippage resulting from said difference between said first roller surface speed and said second roller surface speed; controlling said selected slippage between said first roller surface and said second roller surface, using said first and second drive motors; setting said selected slippage between said first roller surface and said second roller surface as a function of said forme cylinder surface speed; and controlling an amount of said dampening agent supplied to said forme cylinder using said roller train by controlling said selected slippage between said first roller surface and said second roller surface as said function of said forme cylinder surface speed.