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AssigneesFujitsu Limited, Ricoh Company, Ltd.
InventorsTakashi Yamamoto, Masae Nakamura, Masakazu Kinoshita, Yoshimichi Katagiri, Shin-ichi Kuramoto, Hachiro Tosaka, Hiroshi Yamashita, Osamu Uchinokura
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In a method for forming a multicolored toner image in accordance with an electrophotographic process, the addition amount of external additives to a non-added toner is 1.5 to 10.0 parts by weight per 100 parts by weight of the non-added toner in each developing step, the aggregation degree of the toner is within the range of 30 to 80%, and the change ratio of the aggregation degree satisfies the relation: 0.8≦(initial aggregation degree/aggregation degree after no-load revolution of developing portion for 20 hours)≦1.2. According to this method, it becomes possible to form a high-quality color image while a toner always keeps a stable degree of aggregation and a charge amount.
A method for the formation of a color image which comprises the steps of forming an electrostatic latent image in accordance with an electrophotographic process, visualizing said electrostatic latent image by a developer transported by a developer support to form a multicolored toner image whereby monochromatic color toner images are formed by mutually independent developing steps comprising a contact type non-magnetic one-component developing method, and superposing then the resulting monochromatic toner images with one another to form a multicolored toner image, and in which method a toner used in each developing step contains an external additive which comprises inorganic fine particles having a mean particle diameter of 30 to 100 nm, said inorganic fine particles comprising particles of hydrophobic silica having a negative charge polarity, and fine particles having a positive charge polarity and a diameter within the range of 0.3 to 1.5 μm, the addition amount of the external additive to a non-added toner containing no external additive is within the range of 1.5 to 10.0 parts by weight on the basis of 100 parts by weight of said non-added toner, and the aggregation degree of said toner is within the range of 30 to 80%, and the change ratio of the aggregation degree satisfies the following formula:
A method for the formation of a color image which comprises the steps of forming an electrostatic latent image in accordance with an electrophotographic process, visualizing said electrostatic latent image by a developer transported by a developer support to form a multicolored toner image whereby monochromatic color toner images are formed by mutually independent developing steps comprising a contact type non-magnetic one-component developing method, and then superposing the resulting monochromatic toner images with one another to form a multicolored toner image, and in which method a toner used in each developing step contains an external additive which comprises inorganic fine particles having a mean particle diameter of 30 to 100 nm, said inorganic fine particles comprising particles of hydrophobic silica having a negative charge polarity, and fine particles having a positive charge polarity and a diameter within the range of 0.3 to 1.5 μm, the addition amount of the external additive to a non-added toner containing no external additive is within the range of 1.5 to 10.0 parts by weight on the basis of 100 parts by weight of said non-added toner, and the change ratio of the electrostatic charge amount of said toner on an image support for forming and visualizing said electrostatic latent image satisfies the following formula:
Dependencies are inferred from the claim text.