Electrophotographic belt and electrophotographic image forming apparatus

An electrophotographic image forming apparatus, comprising:

• an electrophotographic photosensitive member;
• an intermediate transfer belt to which a toner image formed on the electrophotographic photosensitive member is to be primarily transferred, the intermediate transfer belt being an endless electrophotographic belt comprising an electro-conductive base layer comprising a thermoplastic resin and carbon black, the base layer being a cylindrical extrusion product of a resin mixture comprising the thermoplastic resin and the carbon black;
• and
• a secondary transfer unit that secondarily transfers a toner image, transferred on the intermediate transfer belt, to a recording medium, wherein
• when observing a cross section of the cylindrical extrusion product with a transmission electron microscope (TEM) and obtaining a TEM image with a resolution of 0.01 to 1 nm/pixel, the TEM image including a lowest gray of more than 0 and a highest gray of less than 255, and extracting from the TEM image a square region of 100 nm a side in which the carbon black occupies 50 area % or more,
• among pixels in the square region resulting from the carbon black and constituting 1% by frequency from the lowest gray in a frequency distribution of gray information possessed in each pixel constituting the square region of which a horizontal axis represents gray and vertical axis represents frequency, a pixel group constituted by the pixels that are mutually adjacent having an area of at least 10 nm2 is observed.