Patent ID: 7695100
Filing Date: 2010-04-13
Classification: B41J,F16C

Abstract:
1. An image device comprising: a guide shaft that includes an arc portion in at least part of a cross-section; a movable member that moves back and forth inside the device along the guide shaft when reading or recording image information; a shaft bearing penetrated by the guide shaft at two locations in a movement direction that differ from a center of gravity in the movable member, the shaft bearing including two inclined faces contacted by the arc portion of the guide shaft in the cross-section; a first guide rail disposed parallel to the guide shaft; a second guide rail disposed parallel to the guide shaft; a rotation stopping member provided in the movable member, the rotation stopping member sliding in the direction of rotation of the movable member with the guide shaft as a center and in contact with the first guide rail; and a pressing member provided in the movable member, the pressing member sliding while pressing against the second guide rail, wherein the respective two inclined faces of the shaft bearing are at an angle θf (rad) and an angle θr (rad) with a perpendicular direction, the angle θf (rad) and the angle θr (rad) satisfying the following inequality: and wherein the angle θf (rad) and the angle θr (rad) are determined such that a load Ff (gf) received by the inclined face of a side of the center of gravity of the movable member in the shaft bearing on a downstream side in the movement direction and a load Fr′ (gf) received by the inclined face opposite to the side of the center of gravity of the movable member in the shaft bearing on an upstream side in the movement direction become positive values when calculated when a mass of the movable member is made M, an acceleration that acts on the movable member when accelerating is made G, a load that acts on the first guide rail from the rotation stopping member is made W, a coefficient of friction between the rotation stopping member and the first guide rail is made μ, a pressing force that acts on the second guide rail from the pressing member is made P, a coefficient of friction between the pressing member and the second guide rail is made μ′, a coefficient of friction between the shaft bearings and the guide shaft is made μ″, an angle formed with the direction perpendicular to the pressing force that acts on the second guide rail from the pressing member is made η, in the perpendicular direction, a distance from a contact position of the guide shaft and the shaft bearings to a point where movement force acts in the movable member is made z, a distance to a contact position of the first guide rail and the rotation stopping member is made c, a distance to the center of gravity of the movable member is made j, a distance to a contact position of the second guide rail and the pressing member is made a, in the horizontal direction perpendicular to the movement direction of the movable member, a distance from the contact position of the guide shaft and the shaft bearing to the center of gravity of the movable member is made y, a distance to the contact position of the first guide rail and the rotation stopping member is made d, a distance to the contact position of the second guide rail and the pressing member is made k, in the movement direction of the movable member, a spacing of the two shaft bearings is made b, and