Patent ID: 7392002
Filing Date: 2008-06-24
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image carrier to hold a color toner image thereon; an image forming section to form the color toner image on the image carrier; a control section which detects an amount of positional shift between a registration mark of a reference color and a registration mark of another color, both registration marks being formed on the image carrier by the image forming section for a color-shift-correction; a cleaning section to remove the color toner image formed on the image carrier; and an image detecting section which senses the registration mark on the image carrier and outputs an image detection signal representing the line width of the registration mark; wherein during the execution of a color-shift-correcting mode, where the image forming section forms the registration mark on the image carrier, the control section detects the amount of the position shift of the registration mark and the control section corrects a position of an image according to the amount of the positional shift, the control section calculates the line width of the registration mark from the image detection signal and then compares the line width of the registration mark with a reference value of line width to discriminate between normality and abnormality; then if normality, the control section continues the execution of the color-shift-correcting mode and if abnormality, the control section stops the execution of the color-shift-correcting mode and execute an image forming system restoration mode, where the image forming section forms the color toner image on the image carrier for restoring an image forming system as a restoration image and then the cleaning section removes the restoration image for cleaning the image forming system.