Patent attributes
An image forming device measures calibration patterns printed on a conveying belt and stores the measurement data, which includes data for the density and position of the patterns. Measurement data is deleted from memory when the position of the pattern matches positional data stored in a flash memory for indicating unusable or abnormal positions on the conveying belt. Next, the density data and positional data in each measurement data is checked. If either the density or positional data falls outside of a specified range, then the measurement data is considered abnormal. In this case, the pattern forming position in the measurement data is stored as positional data and the measurement data is deleted. Subsequently, color registration correction is performed based on the remaining normal measurement data.
