JP2006301110A5 - - Google Patents

Claims (6)

An image forming unit for forming an unfixed image on a recording material, and a first energization heating resistance layer and a second energization heating resistance layer along a longitudinal direction on a substrate elongated in a direction perpendicular to the recording material conveyance direction A cylindrical fixing film whose inner peripheral surface is in contact with the heater, a pressure roller that forms a fixing nip portion that sandwiches and conveys a recording material together with the heater via the fixing film, the first and first Fixing means having control means for controlling energization of the two energization heat generating resistance layers, and the resistance value per unit length of each of both ends in the longitudinal direction of the second energization heat generation resistance layer is The ratio of the resistance value per unit length of each end of the first energization heating resistor layer in the longitudinal direction to the resistance value per unit length of the center portion is higher than the center portion. Less than the ratio of the layers, The electric heating resistance layer and the second energization heating resistance layer are connected in parallel to the power source and can be individually controlled by the control means, and the control means continuously connects a plurality of recording materials. In the image forming apparatus that controls the energization ratio of the second energization heating resistance layer to the first energization heating resistance layer to gradually decrease when printing
Power detection means for detecting the power consumed by the heater , the control means in accordance with the integrated value of the detected power of the power detection means when printing on a plurality of recording materials continuously An image forming apparatus, characterized in that a timing for lowering an energization ratio of the second energization heat generating resistance layer to the first energization heat generation resistance layer is set . The value according to the temperature of the heater before starting to energize the first and second energization heating resistance layers to start printing is added to the integrated value of the detected power. The image forming apparatus according to 1. The image forming apparatus according to claim 1 , wherein a threshold value of the integrated value corresponding to a timing of decreasing the energization ratio is set according to a size of the recording material . The image forming apparatus according to claim 1, further comprising a temperature detection unit configured to detect an ambient temperature, wherein a threshold value of the integrated value corresponding to a timing of decreasing the energization ratio is set according to the ambient temperature. . The apparatus has a plurality of print modes in which the number of output sheets per unit time is different, and a threshold value of the integrated value corresponding to a timing to decrease the energization ratio is set according to the print mode. The image forming apparatus according to claim 1 . The image forming apparatus according to claim 1, wherein a value corresponding to a paper feed interval of the recording material is added to an integrated value of the detected power .