Image-forming apparatus and a method for a detecting developer amount therein

An image-forming apparatus comprising:

• an image-forming unit having, at least, a photosensitive member;
• a developing means for supplying developer on an electrostatic latent image on the member for development;
• a developer accommodating housing for accommodating the developer, the housing having a first and second windows made of transparent members respectively arranged at a ceiling and a bottom;
• and a cleaning means for periodically cleaning the first and second windows, said unit being detachably attached to a body of the apparatus;
• and
• a detecting means having a light emitting means arranged at the body and confronting with one of the windows, the light emitting means emitting light through the one of the window into the housing;
• and a light receiving means arranged at the body and confronting with the other of the windows, the light receiving means receiving the light emitted from the light emitting means through the other of the windows to detect an amount of the developer in the housing.

An image forming apparatus comprising:

• a photosensitive member;
• a developing means for supplying developer on an electrostatic latent image on said member;
• a developer accommodating means for accommodating the developer to be supplied to said developing means, said accommodating means having a housing which includes a first and a second window made of transparent members, wherein said first window is arranged at a first part of the housing and the second window is arranged spaced from said first part at the housing;
• a cleaning means for cleaning the first and second windows;
• and
• a detecting means having a light emitting means arranged outside the housing and confronting with one of the windows to illuminate light from the light emitting means therethrough, and a light receiving means arranged outside the housing and confronting with the other of the windows, said light receiving means receiving the light emitted from the light emitting means to detect an amount of the developer in the housing.

An image forming apparatus for forming an image, comprising:

• a developing means for supplying developer to form the image;
• an accommodating means for accommodating the developer to be supplied to said developing means, said accommodating means having a housing which includes a first and a s econd window made of transparent members, wherein said first window is arranged at a first part of the housing and the second window is arranged spaced from said first part at the housing;
• a cleaning emans for periodically cleaning the first and second windows;
• and
• a detecting means having a light emitting means arranged outside the housing and confronting with one of the windows to illuminate light from the light emitting means therethrough, and a light receiving means arranged outside the housing and confronting with the other of the windows, said light receiving means receiving the light emitted from the light emitting means to detect an amount of the developer in the housing.