Image forming apparatus with toner detection

An image forming apparatus which comprises:

• a photoreceptor medium including a substrate and a photosensitive layer formed on the substrate, said substrate having a regularly developed pattern of grooves formed thereon;
• means for electrostatically charging the photoreceptor medium;
• a laser optical system for forming an electrostatic latent image on the photoreceptor medium;
• a developing means for developing the electrostatic latent image into a toner image, said developing means including means for applying a developing bias voltage;
• means for varying a voltage to be applied by the bias voltage applying means;
• means for projecting a beam of light onto the photoreceptor medium so as to reflect therefrom and for measuring a portion of the light beam undergoing a diffuse reflection from the photoreceptor medium, said projecting and measuring means including a light emitting element and a light receiving element, each of said elements having an optical axis, said light emitting and receiving elements being so positioned that a common plane containing the respective optical axes lie substantially parallel to any one of the grooves on the substrate;
• and
• a control means for varying the applied voltage according to a result of measurement carried out by said projecting and measuring means.

An image forming apparatus for forming a visible image on a sheet material, said apparatus comprising:

• a photoreceptor medium including a substrate and a photosensitive layer formed on the substrate, said substrate having a regularly-developed pattern of grooves formed thereon;
• means for forming an electrostatic latent image on the photoreceptor medium, developing the electrostatic latent image into a visible image and transferring the visible image on a sheet material;
• means for measuring the amount of rays of light reflected from the photoreceptor medium and undergoing diffuse reflection therefrom, said measuring means including a light emitting element and a light receiving element, each of said elements having an optical axis, said light emitting and receiving elements being so positioned that a common plane containing the respective optical axes lies substantially parallel to any one of the grooves on the substrate;
• and
• means for controlling said image forming means according to the amount of rays measured by said measuring means.