ELECTROPHOTOGRAPHIC TONER, DEVELOPER CONTAINING THE TONER, AND IMAGE FORMING APPARATUS

摘要

An electrophotographic toner including: a binder resin, wherein the binder resin has one glass transition temperature Tg and the glass transition temperature Tg of the binder resin is within 25° C. to 65° C. as measured in second heating with a differential scanning calorimeter at a heating rate of 5° C./min, and wherein a phase image of the binder resin obtained with an atomic force microscope (AFM) of tapping mode contains first phase difference regions and a second phase difference region such that the first phase difference regions are dispersed in the second phase difference region, where the first phase difference regions correspond to greater phase difference regions and the second phase difference region corresponds to a smaller phase difference region when an intermediate value between a maximum value and a minimum value of the phase differences is used as a threshold.

主权项

1. An electrophotographic toner comprising:
a binder resin, wherein the binder resin has one glass transition temperature Tg and the glass transition temperature Tg of the binder resin is within 25° C. to 65° C. as measured in second heating with a differential scanning calorimeter at a heating rate of 5° C./min, a binarized image of a phase image of the binder resin comprises first phase difference regions each formed of first pixels and a second phase difference region formed of second pixels such that the first phase difference regions are dispersed in the second phase difference region, and the binarized image of the phase image of the binder resin is obtained through a process comprising: measuring the binder resin with an atomic force microscope of tapping mode to obtain phase differences at locations of the binder resin; converting the phase differences to image densities of pixels so that locations having smaller phase differences are dark colored and locations having greater phase differences are light colored; mapping the locations of the binder resin to obtain the phase image; and subjecting the phase image to binarization using, as a threshold, an intermediate value between a maximum value and a minimum value of the image densities so that the image densities of the first pixels are equal to or more than the minimum value but less than the intermediate value and the image densities of the second pixels are equal to or more than the intermediate value but equal to or less than the maximum value.