Heat fixing device

Abstract

Abstract PURPOSE:To obtain a practically uniform heating temperature throughout the overall length of a heat roll by setting plural electrode rings on both ends of the heat roll and bringing a pressure roll and the heat roll into contact with each other between the two rings nearest to the center of the heat roll out of these electrode rings. CONSTITUTION:When a heat roll 1 and a pressure roll 2 which are pressed to each other are rotated by a driving mechanism which is not shown in Fig. and a voltage is applied to a feeding brush 13 by, for example, a commercial AC power source, a current is flowed to a part having with l1 of a resistance heating body 8 through electrode rings 9b and 9'a, and the current is flowed between the electrode rings 9a and 9b and between the rings 9'a and 9'b also. The current flowed to the resistance heating body 8 is as shown by solid-line arrows or broken-line arrows in Fig. Since not only the center part having the width l1 but also part having the width l2 in both ends of the resistance heating body 8 are heated, the temperature distribution on the surface of the heat roll 1 is kept uniform practically in the axial direction to correct the fall of temperature in both ends. Consequently, when a supporting material 16 holding a toner image 15 is allowed to pass through a nip part between the heat roll 1 and the pressure roll 2, a high-quality fixed image is obtained without a fixing defect in both end parts.

Inventors

• 👤 Keitaro Yamashita
• 👤 恵太郎 山下

Bibliographic Details