Patent ID: 7684749
Filing Date: 2010-03-23
Classification: B65H,G03G

Abstract:
1. An image forming apparatus, comprising: an image carrying member for carrying a toner image while rotating; a transfer section for transferring the toner image from the image carrying member to a transfer sheet; a transfer attitude correcting section for correcting a transfer attitude of the transfer sheet to receive the toner image and for conveying the corrected transfer sheet to the transfer section with a timing to match with the movement of the toner image; wherein the transfer attitude correcting section comprises: a roller unit including a base board rotatable around a center of rotation and a registration roller mounted on the base board, a detecting section for detecting a position of the transfer sheet being conveyed by the registration roller; and a control section for control the roller unit based on detection data detected by the detecting section so as to correct a skew of the transfer sheet by rotating the base board and to correct a deviation of a transfer position of the transfer sheet by shifting the registration roller on the base board, wherein the detecting section detects a first point and a second point on a side of the transfer sheet locating along the conveying direction of the transfer sheet with a predetermined time interval Δt, the control section calculates an amount of the skew of the transfer sheet based on the detection data of the first and second points and controls the roller unit based on the amount of the skew, and wherein the registration roller is adapted to change the conveying speed into plural different conveying speeds, the detecting section changes the time interval Δt in accordance with a conveying speed so as to make the distance in the conveying direction of the transfer sheet between the first and second points to be constant regardless of the conveying speed.