Patent ID: 8186003

Claim:
A designing method of a wiper strip, the wiper strip including a contacting portion adapted to engage a wiping surface through a liquid film, the designing method comprising: selecting a maximum thickness of the liquid film (h m ) equal to or smaller than 425 nm, the maximum thickness of the liquid film is formed at a corresponding location of the contacting portion of the wiper strip, at which a maximum pressing pressure is developed in a pressing pressure profile of the contacting portion at time of wiping the wiping surface with the wiper strip, wherein the pressing pressure profile is taken in an imaginary plane that is perpendicular to a longitudinal direction of the wiper strip; obtaining a maximum pressure gradient value in the pressing pressure profile based on the following equation: ( ⅆ P ⅆ x ) max = 8 9 · η · U h m 2 where ( ⅆ P ⅆ x ) max denotes the maximum pressure gradient value, h m denotes the maximum thickness of the liquid film as defined above, η denotes the coefficient of viscosity of the liquid, and U denotes the moving speed of the wiper strip; setting design factors of the wiper strip based on the maximum pressure gradient value to achieve the maximum pressure gradient value in the pressing pressure profile at the contacting portion of the wiper strip at the time of wiping the wiping surface with the wiper strip, the setting of design factors including at least one of selecting and modifying at least one of a material of the wiper strip, a shape of the contacting portion of the wiper strip, and a size of the contacting portion of the wiper strip; and forming the wiper strip with the set design factors.