Fixing device and image forming apparatus

摘要

A fixing device includes a fixing rotation body heating and fixing an unfixed image onto a recording medium; a pressing rotation body pressing the recording medium to the fixing rotation body; a first temperature detection unit detecting a temperature of the fixing rotation body; and plural second temperature detection units detecting a temperature of the pressing rotation body. Further the fixing device selects a predetermined second temperature detection unit from the plural second temperature detection units depending on an operation mode of the fixing device, and the fixing device detects the temperature of the pressing rotation body by using the predetermined second temperature detection unit selected by the fixing device.

主权项

1. A fixing device comprising:
a fixing rotation body configured to be in contact with a side of a recording medium, an unfixed image having been formed on the side of the recording medium, and heat and fix the unfixed image onto the recording medium; a pressing rotation body configured to be in contact with another side of the recording medium, no unfixed image having been formed on the other side of the recording medium, and press the recording medium to the fixing rotation body; a first temperature detector configured to detect a temperature of the fixing rotation body; and plural second temperature detectors configured to detect a temperature of the pressing rotation body; wherein the fixing device selects a predetermined second temperature detector from the plural second temperature detectors depending on an operation mode of the fixing device, wherein the fixing device detects the temperature of the pressing rotation body by using the predetermined second temperature detector selected by the fixing device, wherein the plural second temperature detectors include a non-contact-type thermistor configured to detect a temperature of a sheet feeding region of the pressing rotation body and a contact-type thermistor configured to detect a temperature of a non-sheet feeding region of the pressing rotation body, the fixing device further comprising: a detector configured to detect a width of the recording medium; and a heater to heat a region of the fixing rotation body, the region corresponding to the width detected by the detector, wherein the fixing device feeds any of plural types of recording media having different widths from each other, and wherein the heater heats the region based on the temperature detected by the non-contact-type thermistor, when the non-contact-type thermistor is used to detect a temperature of a non-sheet feeding region of the pressing rotation body.