| 主权项 |
1. An electrophotographic photosensitive member to be negatively electrified, comprising: a conductive substrate; a photoconductive layer which is formed from hydrogenated amorphous silicon on the conductive substrate; and a surface layer which is formed from hydrogenated amorphous silicon carbide on the photoconductive layer, wherein
the surface layer has a change region in which a ratio (C/(Si+C)) of the number of carbon atoms (C) with respect to the sum of the number of silicon atoms (Si) and the number of carbon atoms (C) gradually increases toward a surface side of the electrophotographic photosensitive member from a side of the photoconductive layer, the change region has an upper charge injection prohibiting portion containing a Group 13 atom, and a surface-side portion which is positioned closer to the surface side of the electrophotographic photosensitive member than the upper charge injection prohibiting portion and does not contain the Group 13 atom, and when a precipitous property of the distribution of the Group 13 atom in a boundary portion between the surface-side portion and the upper charge injection prohibiting portion is evaluated with a following evaluation method A, the precipitous property satisfies a relation expressed by a following expression (A7), wherein the evaluation method A of the precipitous property of the distribution of the Group 13 atom comprises the following steps of: (A1) obtaining a depth profile of a surface of the electrophotographic photosensitive member by an SIMS analysis; (A2) making D represent a distance from the surface of the electrophotographic photosensitive member, in the depth profile, making a function f(D) of the distance D represent an ionic strength of the Group 13 atom at the distance D, making f(DMAX) represent a maximal value of f(D), making f″(D) represent a second order differential of f(D), making DA represent a distance of a point at which when the D is increased toward the photoconductive layer, f″(D) changes from f″(D)=0 to f″(D)<0, from the surface of the electrophotographic photosensitive member, and making DB represent a distance of a point at which f″(D) subsequently changes from f″(D)<0 to f″(D)=0, from the surface of the electrophotographic photosensitive member; (A3) making DS represent a first distance among the distances D which satisfy f((DA+DB)/2)≧f(DMAX)×0.5, when the upper charge injection prohibiting portion is viewed from the surface of the electrophotographic photosensitive member, and making a standard ionic strength f(DS) represent the ionic strength f(D) of the Group 13 atom at the distance DS; (A4) making a precipitous property ΔZ represent a length in a thickness direction of the boundary portion, in which the ionic strength of the Group 13 atom in the boundary portion between the surface-side portion and the upper charge injection prohibiting portion increases from 16% to 84%, when viewed from the surface of the electrophotographic photosensitive member and when the standard ionic strength f(DS) is determined to be 100%; (A5) producing a standard laminated film A which has a film A1 that has a composition corresponding to the upper charge injection prohibiting portion and a film A2 that has a composition corresponding to the surface-side portion, stacked in this order; (A6) determining a surface of the film A2 as a surface of the standard laminated film A with respect to the standard laminated film A, and determining a precipitous property ΔZ0 in the boundary portion between the film A2 and the film A1 of the standard laminated film A, with similar steps to the steps (A1) to (A4); and
(A7)determining 1.0≦ΔZ/ΔZ0≦3.0 (A7). |
