HEATING DEVICE, FIXING DEVICE, AND IMAGE FORMING DEVICE

To present an index for quantitatively grasping a detection error of infrared temperature detection means.SOLUTION: In a heating device which includes: a pair of rotary bodies 21, 22 forming a nip part N by being brought into contact with each other; a heating source 23 which heats at least one of the pair of rotary bodies 21, 22, and infrared temperature detection means 26 arranged in a non-contact state by being opposed to the outer peripheral surface of the rotary body 21 and detecting the temperature by infrared rays emitted from the rotary body 21, a root sum square chroma (C) of saturation (a*, b*), which are color characteristics measured from the outer peripheral surface side of the rotor 21, is set to satisfy a relationship of the following expression (15) in which the root sum square chroma is equal to or less than a predetermined value C1.SELECTED DRAWING: Figure 2 【課題】赤外線温度検知手段の検知誤差を定量的に把握する指標を提示する。【解決手段】互いに接触してニップ部Ｎを形成する一対の回転体２１，２２と、一対の回転体２１，２２の少なくとも一方を加熱する加熱源２３と、回転体２１の外周面に対向して非接触に配置され、回転体２１から発する赤外線により温度を検知する赤外線温度検知手段２６と、を備える加熱装置において、回転体２１の外周面側から測定される色特性である彩度（ａ＊，ｂ＊）の二乗和平方根クロマ（Ｃ）が、所定値Ｃ１以下となる下記式（１５）の関係を満たすように設定される。【数１５】TIFF2024032352000016.tif16170【選択図】図２