Patent ID: 8121501

Claim:
An image forming apparatus including an image carrier on which a toner image depending on input image data is formed, a transfer sheet carrier for forming a transfer sheet transport path and transferring the toner image formed on the image carrier onto a sheet being transported, a color sensor disposed in a vicinity of the transfer sheet transport path, a control portion for controlling an image forming operation, and an image adjustment function which performs an image adjustment using a reference toner image prior to printing when a color print mode is selected, wherein, a separation driving mechanism for separating the transfer sheet carrier from the image carrier and then contacting them and a sheet re-feeding transport path for feeding the sheet which has passed through the transfer sheet transport path again to the transfer sheet transport path are further included, and the control portion performs a series of control at the time of the image adjustment, to form the reference toner image on a surface of the transfer sheet carrier, to detect the reference toner image by the color sensor, to adjust developing conditions based on color information of the detected reference toner image, then, to transport the sheet on the transfer sheet transport path in a state where the transfer sheet carrier is separated from the image carrier by the separation driving mechanism, to detect colors of the sheet by the color sensor, and to correct a color tone of the input image data based on the detected color of the sheet.