Toner with organically treated alumina for developing electrostatic image

摘要

A toner for developing electrostatic images includes: toner particles and organically treated alumina powder. The organically treated alumina powder has an X-ray diffraction characteristic showing a maximum X-ray intensity level Ia-max and a minimum X-ray intensity level Ia-min in a 2 theta range of 20 to 70 degrees providing a ratio Ia-max/Ia-min of below 6. The alumina powder is amorphous or has a low-crystallinity of gamma -form, thereby showing a low agglomeratability to function as an effective flowability-improving agent for a toner. The structural water contained in the alumina powder contained favors hydrophobization treatment thereof and functions to suppress a charge-up phenomenon in a low humidity environment after the hydrophobization.