Electrophotographic apparatus and electrophotographic method featuring a photosensitive member having a linear EV characteristic

An electrophotographic method comprising:

• a step of guiding a light beam onto a reflecting surface of a rotary polygon mirror and deflecting the light beam so as to satisfy the following inequality:
• 3.0≧D/W≧1.5,
• where D is a diameter of the light beam at the reflecting surface of the rotary polygon mirror, and W is a width in a main scanning direction of the reflecting surface of the rotary polygon mirror;
• and
• a step of forming an image with the light beam on a recording medium comprising an a-Si base photosensitive member, the a-Si base photosensitive member including a surface layer having a film thickness varying in the main scanning direction, and having a refractive index varying in the main scanning direction due to a variance in film quality depending on an angle of the light beam incident to the surface layer and having a linear photosensitivity (EV) characteristic.

An electrophotographic apparatus comprising:

• a light scanning device for guiding a light beam onto a reflecting surface of a rotary polygon mirror and deflecting the light beam;
• and
• a recording medium, which the light beam deflected by said light scanning device scans to form an image, said recording medium comprising an a-Si base photosensitive member, said a-Si base photosensitive member including a surface layer having a film thickness varying in a main scanning direction depending on an angle of the light beam incident to said surface layer, and further having a linear photosensitivity (EV) characteristic,
• wherein the following inequality is satisfied:
• 3.0≧D/W≧1.5,
• where D is a diameter of the light beam at the reflecting surface of said rotary polygon mirror, and W is a width in a main scanning direction of said reflecting surface of said rotary polygon mirror.

An electrophotographic method comprising:

• a step of guiding a light beam onto a reflecting surface of a rotary polygon mirror and deflecting the light beam so as to satisfy the following inequality:
• 3.0≧D/W≧1.5,
• where D is a diameter of the light beam at the reflecting surface of the rotary polygon mirror, and W is a width in a main scanning direction of the reflecting surface of the rotary polygon mirror;
• and
• a step of forming an image with the light beam on a recording medium comprising an a-Si base photosensitive member, the a-Si base photosensitive member including a surface layer having a film thickness varying in the main scanning direction depending on an angle of the light beam incident to the surface layer, and having a linear photosensitivity (EV) characteristic.