TONER, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

To provide a toner that can prevent the occurrence of an image defect when an image is formed in a non-magnetic one-component developing system, while ensuring low-temperature fixability.SOLUTION: A toner includes a toner particle 10. The toner particle 10 includes a toner base particle 11 including a binder resin, and an external additive attached to the surface of the toner base particle 11. The external additive includes fluorine-containing particles 12. The fluorine-containing particles 12 each include at least fluorine atoms in a surface layer. The amount of the fluorine-containing particles 12 is 0.10 parts by mass or more and 0.50 parts by mass or less based on 100 parts by mass of the toner base particle 11. When an ultrasonic treatment is executed of adding ultrasonic vibration with an output of 200 W, a frequency of 28 kHz, and an amplitude of 25 μm for five minutes in 500 mL of an aqueous dispersion liquid including 5 g of the toner and 50 g of a nonionic surfactant, the amount of the fluorine-containing particles 12 not separated from and attached to the toner base particle 11 is 0% by mass or more and 20% by mass or less with respect to the amount of the attached fluorine-containing particles 12 before the ultrasonic treatment is executed.SELECTED DRAWING: Figure 1 【課題】低温定着性を確保しつつ、非磁性１成分現像方式で画像を形成する場合において画像不良の発生を抑制できるトナーを提供する。【解決手段】トナーはトナー粒子１０を含む。トナー粒子１０は、結着樹脂を含むトナー母粒子１１と、トナー母粒子１１の表面に付着した外添剤とを備える。外添剤は、フッ素含有粒子１２を含む。フッ素含有粒子１２は、少なくとも表層にフッ素原子を含む。フッ素含有粒子１２の量は、１００質量部のトナー母粒子１１に対して、０．１０質量部以上０．５０質量部以下である。トナー５ｇ及びノニオン界面活性剤５０ｇを含む水系分散液５００ｍＬ中で出力２００Ｗ、周波数２８ｋＨｚ、振幅２５μｍの超音波振動を５分間加える超音波処理を実施したとき、トナー母粒子１１から脱離せずに付着しているフッ素含有粒子１２の量が、超音波処理を実施する前のフッ素含有粒子１２の付着量に対して、０質量％以上２０質量％以下である。【選択図】図１