Image forming apparatus utilizing a plurality of image formation velocities

摘要

An image forming apparatus includes a plurality of latent image bearers, a latent image writer, a plurality of developing units, a primary transfer unit, a secondary transfer unit, an adjuster, a pattern image formation controller, a color deviation detector, a color deviation correction controller, and an image-formation-mode setting unit. The color deviation correction controller executes color deviation correction control in the separated state. The image-formation-mode setting unit sets a normal linear-velocity image formation mode in which an image is formed at a normal linear velocity and at least one non-normal linear-velocity image formation mode including a low linear-velocity image formation mode in which an image is formed at a low linear velocity slower than the normal linear velocity. A plurality of image formation velocities including the normal linear velocity and the low linear velocity is set, and an execution timing of the color deviation correction control in image formation at the normal linear velocity and an execution timing of the color deviation correction control in image formation at the low linear velocity are set independently from each other.

主权项

1. An image forming apparatus comprising:
a plurality of latent image bearers; a latent image writer to write latent images to the latent image bearers; a plurality of developing units to develop the latent images of the latent image bearers and form toner images of different colors; a primary transfer unit to transfer the toner images on the latent image bearers to an intermediate transferer; a secondary transfer unit to transfer the toner images from the intermediate transferer to a sheet; an adjuster to cause the intermediate transferer and the secondary transfer unit to be in a contact state or a separated state; a pattern image formation controller to form a pattern image on the intermediate transferer via the latent image bearers to detect color deviation; a color deviation detector to detect the color deviation of the pattern image borne on the intermediate transferer; a color deviation correction controller to execute color deviation correction control in the separated state; and an image-formation-mode setting unit to set a normal linear-velocity image formation mode in which an image is formed at a normal linear velocity and at least one non-normal linear-velocity image formation mode including a low linear-velocity image formation mode in which an image is formed at a low linear velocity slower than the normal linear velocity, wherein a plurality of image formation velocities including the normal linear velocity and the low linear velocity is set, and an execution timing of the color deviation correction control in image formation at the normal linear velocity and an execution timing of the color deviation correction control in image formation at the low linear velocity are set independently from each other.