JP2006106686A5 - - Google Patents

Claims (7)

An image forming unit for forming an image on a recording material;
A heating body, a pressure roller that forms a fixing nip portion together with the heating body, and power control means for controlling power supplied to the heating body so that the temperature of the heating body maintains a target temperature, A fixing unit that heats and fixes the image on the recording material to the recording material while nipping and conveying the recording material carrying the image at the fixing nip portion;
In an image forming apparatus having
In the period in which the fixing nip portion forms an interval between a preceding recording material and a succeeding recording material when images are continuously formed on a plurality of recording materials, the recording material has the fixing nip portion at the target temperature. The recording material passes through the fixing nip portion in the first fixing processing mode in which the temperature is equal to or lower than the target temperature when passing, and the period during which the fixing nip portion is in the interval. And a second fixing processing mode in which the temperature is set to be higher than the target temperature when the image forming apparatus is in operation. The image forming apparatus according to claim 1, wherein the interval in the second fixing processing mode is set longer than that in the first fixing processing mode. The apparatus further includes a moisture amount detecting unit that detects a moisture amount of the recording material, and the fixing nip portion in the second fixing processing mode is set to the interval according to the moisture amount detected by the moisture amount detecting unit. The image forming apparatus according to claim 1, wherein the target temperature of the period is set. The apparatus further includes an environment detection unit that detects at least one of an environmental temperature and a humidity in which the apparatus is installed, and the second fixing according to at least one of the environmental temperature and the humidity detected by the environment detection unit. The image forming apparatus according to claim 1, wherein the target temperature is set for a period in which the fixing nip portion in the processing mode is the interval.   The apparatus further includes a detecting unit that detects at least one of a thickness and a type of the recording material, and in the second fixing processing mode according to at least one of the thickness and the type of the recording material detected by the detecting unit. The image forming apparatus according to claim 1, wherein the target temperature for a period in which the fixing nip portion is the interval is set. The apparatus further includes a counter that counts the number of recording materials, and the fixing nip portion in the second fixing processing mode becomes the interval according to the number of continuous image formations of the recording material detected by the counter. The image forming apparatus according to claim 1, wherein the target temperature for a given period is set. The heating body includes an endless belt and a heater that is in contact with an inner surface of the endless belt and is supplied with the electric power, and the fixing nip portion includes the heater and the pressure roller via the endless belt. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed by: