| 摘要 |
PURPOSE:To control the damping water amount in high preciseness, by a simple mechanism wherein a detecting roller externally contacted with a form-damping roller is provided and the water content of the form-damping roller held between said form- damping roller and a water distributing roller is estimated from the resistance value between both rollers to regulate the rotary speed of a water fountain roller by said value. CONSTITUTION:In a damping water supply apparatus wherein damping water is transferred to a water holdable ducter roller 4 from a speed variable and rotatable water fountain roller 3 and supplied to a printing surface 2 through a water distributing roller 6 made of a conductive metal and form-damping rollers 7, 7 having water holding layers on the surfaces thereof, a detecting roller 9 made of a conductive metal is provided so as to be rotated in externally contacted relation to the form-damping roller 7 and this detecting roller 9 and the water distributing roller 6 are used as a pair of electrodes to apply alternating voltage to both rollers to detect the water holding amount of the form-damping roller 7 held between both rollers 6, 9 as an electric resistance value while the rotary speed of the water fountain roller 3 is regulated on the basis of said value to control a water applying amount to the printing surface 2. |
