| 摘要 |
PURPOSE:To make the warming-up time of a fixation device shorter without increasing its maximum power consumption, by dividing the circumferential area of its heating roller and making the calorific value of the heating unit in a 1st section higher than of the heating unit in a 2nd section. CONSTITUTION:A heating roller 15 is provided with an adiabatic layer 13 which makes an electrically insulating and adiabatic actions and a film-like resistance body 12 at the outside of a hollow roll 3. The resistance body 12 is divided into plural sections in the circumferential direction of the roll 3 by means of a separation layer 14 formed of an electrically insulating and low-thermal conductivity substance. Thus plural heating units 12 are formed in the circumferential direction of this heating roller 15. The heating roller 15 thus formed is covered with a coating layer 5 made of silicon rubber, etc. The length L1 of a 1st heating section including the nip width Lf is set to satisfy Formula I and the calorific value of the 1st heating unit 12 in the 1st section L1 is made higher than that of the heating unit 12 in the 2nd section L2. The (tu) and (v) of the formula respectively represent the time required for raising the surface temperature of the coating layer 5 to a prescribed fixing temperature (warming- up time) and the peripheral speed of the heating roller 15.
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