Patent ID: 8340552
Filing Date: 2012-12-25
Classification: G03G

Abstract:
1. An image forming apparatus that includes two or more latent-image carriers of which the surfaces go around the respective latent-image carriers to be aligned in a surface moving direction of an object onto which visible images are to be transferred, and obtains a final image in such a manner that the image forming apparatus causes the surfaces of the latent-image carriers to go around the respective latent-image carriers by transmitting a rotational driving force from a drive source to respective driven transmission rotating bodies provided to the latent-image carriers, and transfers visible images, which are obtained by developing respective latent images on the surfaces of the latent-image carriers formed at predetermined latent-image forming points, onto the object in a superimposed manner, wherein a distance L between transfer sections of two latent-image carriers having the same diameter R is configured to deviate from a value of an integral multiple of a circumferential length πR of the two latent-image carriers, a first driven transmission rotating body provided to a first latent-image carrier, one located on the upstream side in the surface moving direction of the object out of the two latent-image carriers, and a second driven transmission rotating body provided to a second latent-image carrier, the other one located on the downstream side in the surface moving direction of the object out of the two latent-image carriers, are each made up of the same rotating body, relative rotational positions of the first driven transmission rotating body and the second driven transmission rotating body are set so that a phase of a fluctuation component of angular velocity of the first driven transmission rotating body due to eccentricity of the first driven transmission rotating body and eccentricity of the second driven transmission rotating body at a point of time when a specific point on the object passes through the transfer section of the first latent-image carrier coincides with a phase of a fluctuation component of angular velocity of the second driven transmission rotating body due to the eccentricity of the second driven transmission rotating body at a point of time when the specific point passes through the transfer section of the second latent-image carrier, a drive transmission rotating body connected to the side of the drive source is directly connected to the second driven transmission rotating body, and a driven rotating body, which rotates dependently, is directly connected to the first driven transmission rotating body and the second driven transmission rotating body, whereby both the first latent-image carrier and the second latent-image carrier are driven by the rotational driving force transmitted through the drive transmission rotating body, and on the assumption that an angle between the first virtual straight line and a second virtual straight line connecting the rotation center of the second driven transmission rotating body and the rotation center of the drive transmission rotating body when viewed from the direction of the rotating shaft of the driven rotating body is defined as α with a direction opposite to the rotating direction of the second driven transmission rotating body as positive, and an angle between the first virtual straight line and a third virtual straight line connecting the rotation center of the first driven transmission rotating body and the rotation center of the driven rotating body when viewed from the direction of the rotating shaft of the driven rotating body is defined as β with a direction opposite to a rotating direction of the first driven transmission rotating body as positive, when an ideal amplitude ratio Y, which indicates a ratio of an ideal amplitude of radial run-out of the first driven transmission rotating body that can theoretically zero relative transfer misalignment which occurs between the first latent-image carrier and the second latent-image carrier due to the eccentricities of the first driven transmission rotating body and the second driven transmission rotating body to an actual amplitude of radial run-out of the second driven transmission rotating body due to the eccentricity that the second driven transmission rotating body has, is defined by the following Equation (1), the diameter R of the two latent-image carriers, the distance L between the transfer sections of the two latent-image carriers, the angle α, and the angle β are set so that an absolute value of a value obtained by subtracting 1 from the ideal amplitude ratio Y is equal to or smaller than a maximum allowable amplitude ratio indicating a ratio of 10 μm, a maximum allowable amount of the transfer misalignment, to the actual amplitude of the radial run-out of the second driven transmission rotating body: