Patent Document ID: 7587157
Application ID: 11627205
Patent Status: 1

Claim One:
1. An image forming apparatus, comprising: a latent image carrier having a moving surface on which a latent image is formed; a drive control mechanism configured to control a drive of the latent image carrier so as to match a rotation angular speed of the latent image carrier with a target rotation angular speed thereof; a surface moving member having a moving surface on which an adjustment pattern for use in controlling the drive of the latent image carrier is formed; an image forming mechanism configured to develop the latent image with toner and transfer a resultant toner image on the moving surface of the surface moving member so as to form the adjustment pattern along a surface moving direction thereof; a pattern sensor configured to detect the adjustment pattern; and a correction mechanism configured to correct the target rotation angular speed of the latent image carrier based on an amplitude and a phase of a variable component in a pattern interval of the adjustment pattern detected with the pattern sensor, wherein the correction mechanism corrects the target rotation angular speed of the latent image carrier by superposing a correction value on an uncorrected value of the target rotation angular speed, the correction value being obtained by calculating the amplitude and the phase of the variable component in the pattern interval of the adjustment pattern indicating a periodic variation in a surface moving speed of the latent image carrier from the detection data of the adjustment pattern, dividing the amplitude of the variable component by 2×R×sin(φ/2)/ω 0 , and delaying the phase of the variable component by φ/2, where “ω 0 ” represents an average rotation angular speed of the latent image carrier, “R” represents a rotation radius of the latent image carrier, and “φ” represents an angle formed with two imaginary lines connecting a rotation center of the latent image carrier to each of a latent image writing position and a transfer position on the surface of the latent image carrier on an imaginary plane perpendicular to a rotation axis of the latent image carrier.