Toner for developing electrostatic image, method for producing the same, developer, image forming apparatus, process cartridge, and image forming method
AssigneeRicoh Company, Ltd.
InventorHideki SUGIURA
Life of this patent
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Abstract
A toner is disclosed, for developing electrostatic images by means of image forming apparatuses, that comprises toner particles, and an external additive, wherein the toner particles comprise a binder resin and a colorant, the external additive is introduced onto the surface of the toner particles, the external additive liberates from the surface of the toner particles in a rate of 7% to 50% under the condition that the toner is dispersed within a surfactant-containing electrolyte at 20 W output power and 20 kHz frequency for one minute by means of an ultrasonic homogenizer.
Claims13
A method of producing a toner for developing an electrostatic image comprising:
- preparing toner particles that comprise at least a binder resin and a colorant, and adding at least two groups of inorganic fine particles to the toner particles, at least two of the groups differing in average primary-particle diameter, wherein at least one group having a larger average primary-particle diameter than another group is added to the toner particles in an aqueous medium that comprises a surfactant having a polarity which is opposite the polarity of a polar group attached to a surface of the toner particles.
Dependencies are inferred from the claim text.