Fusing Roller Temperature Control for Image Quality

The patent applies preliminary action by rotating the fusing roller and pressure roller pair for a predetermined period before starting the warm-up operation. This preliminary rotation ensures that the pressure roller surface is pre-heated through contact with the fusing roller, preventing subsequent heat transfer that would cause temperature drops when the rollers are rotated during actual image formation. The control unit measures the temperature change amount during this preliminary rotation period to determine appropriate image formation timing.

The patent applies parameter changes by dynamically adjusting the image formation timing based on the measured temperature change amount during preliminary rotation. The control unit determines the appropriate delay period before allowing recording material to reach the fusing portion, optimizing the balance between preventing fusing defects and minimizing first print time. This adaptive timing adjustment ensures the fusing roller temperature has recovered sufficiently while avoiding unnecessary delays.

The patent applies feedback by measuring the actual temperature change amount of the fusing roller surface during preliminary rotation and using this measured value to determine the appropriate image formation timing. Instead of estimating pressure roller temperature based on theoretical calculations or fixed parameters, the system directly measures the temperature change and adjusts the timing accordingly, ensuring accurate temperature control despite variations such as eccentricity in the roller assembly.