Disclosed is an image formation method using electrophotography, comprising the steps of supplying a developer by a developing device (17) onto a photosensitive drum (11) in rotation to form a toner image thereon, transferring the formed toner image onto a transfer paper to form an image on the transfer paper, and removing untransferred developer by use of a cleaning blade (21), wherein an OPC photosensitive drum (11) is used for the photosensitive drum and includes a photosensitive layer (27, 29) being formed on an electrically conductive base (25) and having an initial thickness which is a value within a range of 20 to 50 mm,and wherein the amount X of reduction in the thickness of the photosensitive layer (27, 29) in the OPC photosensitive drum (11) satisfies the following expression (1) 0.5 µm X: by way of example, the amount (µm) of reduction in the thickness of photosensitive layer (27, 29) when 10,000 sheets have been printed at printing speed of 6 sheets/ min using A4 size transfer paper longitudinal feeding apparatus; and
R: diameter (mm) of OPC photosensitive drum (11).