Patent ID: 7470447

Claim:
A fluid discharge method for intermittently discharging fluid, the fluid discharge method comprising: feeding the fluid from a fluid supply device to a gap defined between opposed relatively moving surfaces of two members while keeping the two members moving relative to each other along a direction of the gap, and utilizing a pressure change caused by changing the gap so that the fluid is intermittently discharged through a discharge port communicating with the gap, wherein the opposed relatively moving surfaces of the two members are provided in n sets, where n is an integer not less than 1, wherein given a total volume V 1 (mm 3 ) of the n sets of the opposed relatively moving surfaces, a total volume V 2 (mm 3 ) of flow passages that connect the n sets of the opposed relatively moving surfaces and the fluid supply device to each other, an absolute value X st (mm) of a stroke of the n sets of the opposed relatively moving surfaces that move relative to each other, a time T st (sec) required for the n sets of the opposed relatively moving surfaces to move by the stroke X st , a fluid internal resistance R S (kgsec/mm 5 ) of the fluid supply device, a fluid resistance R n (kgsec/mm 5 ) of the discharge port, a modulus of elasticity of volume K (kg/mm 2 ) of the fluid, an effective area S P (mm 2 ) of the opposed relatively moving surfaces, and a sum P s0 (kg/mm 2 ) of a maximum pressure of the fluid supply device and an auxiliary pressure for introducing the fluid into the fluid supply device, and wherein if it is defined that V S =V 1 +V 2 and that a time constant T and an intermittent interception control parameter II c are T = R s ⁢ R n R n + n ⁢ ⁢ R S ⁢ V s K ⁢ ⁢ and ⁢ ⁢ I ⁢ ⁢ I c = R s ⁢ S p ⁢ X s ⁢ ⁢ t ⁡ ( 1 - ⅇ - T s ⁢ ⁢ t T ) 2 ⁢ P s0 ⁢ T s ⁢ ⁢ t , respectively, then it holds that II c >1.