IMAGE FORMING APPARATUS

• Main Author: SAKAMAKI TOMOYUKI
• Format: Patent
• Language: English; Japanese
• Published: 12.11.2015
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To maintain fluidity of a developer while suppressing the accumulation of an external additive in a developer during image formation with high image ratio after endurance against environment.SOLUTION: In an image forming apparatus 100 that supplies a toner from a replenishment toner bottle 34 and perform image formation with a developing device 4 by using the toner, the toner has at least two types of external additives added thereto, and when the addition amount of a first external additive T2, of the two types of external additives, is Wh (volume% based on toner) and the addition amount of a second external additive T1 is Wl (volume% based on toner), the value Wh+Wl in an initial toner T1 in a developer to be accommodated in advance in the developing device 4 is larger than the value Wh+Wl in a replenishment toner T2 in a developer accommodated in the replenishment toner bottle 34, and the fluidity of the replenishment toner T2 is higher than the fluidity of the initial toner T1. 【課題】耐久時における高画像比率の画像形成時の現像剤内の外添剤の蓄積を抑制しながら、現像剤の流動性を維持すること。【解決手段】補給トナーボトル３４から現像装置４にトナーを補給し、トナーを用いて現像装置４が画像形成を行う画像形成装置１００において、トナーには少なくとも２種類の外添剤が添加されており、前記２種類の外添剤のうち、第一外添剤Ｔ２の添加量をＷｈ（トナーに対する体積％）、第二外添剤Ｔ１の添加量をＷｌ（トナーに対する体積％）とした場合に、現像装置４に予め収納される現像剤の初期トナーＴ１におけるＷｈ＋Ｗｌの値が、補給トナーボトル３４に収納される現像剤の補給トナーＴ２におけるＷｈ＋Ｗｌの値よりも大きく、補給トナーＴ２の流動性が、初期トナーＴ１の流動性よりも高いことを特徴とする。【選択図】図２