ELECTROPHOTOGRAPHIC PHOTORECEPTOR, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS

To provide an electrophotographic photoreceptor that, when images are continuously formed, prevents the occurrence of unintended light and shade in the formed images.SOLUTION: An electrophotographic photoreceptor comprises: a conductive substrate; an undercoat layer provided on the conductive substrate; a charge generating layer provided on the undercoat layer; a charge transport layer provided on the charge generating layer; and a protective layer provided on the charge transport layer. The undercoat layer contains a conducting agent, and the ratio of the number of primary particles of the conducting agent to the total of the number of the primary particles of the conducting agent and the number of secondary particles of the conducting agent is 58% or less. The charge mobility μ(CTL) of the charge transport layer and the charge mobility μ(OCL) of the protective layer satisfy μ(CTL)≥1.0×10-5(cm2/Vs) and μ(OCL)≥0.68×10-5(cm2/Vs).SELECTED DRAWING: Figure 1 【課題】連続して画像を形成したときにおける形成した画像中に意図しない画像の濃淡の発生を抑制する電子写真感光体の提供。【解決手段】導電性基体と、前記導電性基体の上に設けられる下引層と、前記下引層の上に設けられる電荷発生層と、前記電荷発生層の上に設けられる電荷輸送層と、前記電荷輸送層の上に設けられる保護層と、を備え、前記下引層が導電剤を含み、前記導電剤の一次粒子の数が、前記導電剤の一次粒子の数及び前記導電剤の二次粒子の数の合計に対して、５８％以下であり、前記電荷輸送層の電荷移動度μ（ＣＴＬ）及び前記保護層の電荷移動度μ（ＯＣＬ）がμ（ＣＴＬ）≧１．０×１０－５（ｃｍ２／Ｖｓ）かつμ（ＯＣＬ）≧０．６８×１０－５（ｃｍ２／Ｖｓ）を満たす電子写真感光体。【選択図】図１