Apparatus for evaluating characteristics of photosensitive drum for electrophotography

An exposure light quantity supervising method adaptable to an apparatus for evaluating characteristics of a photosensitive drum for use in electrophotography arranged such that light emitted from an exposure light source and reflected and deflected by a reflecting mirror is applied to a photosensitive drum and illuminance of said photosensitive drum is detected by an illuminance measuring probe to supervise the quantity of light applied to the surface of said photosensitive drum in accordance with the detection output from said illuminance measuring probe, said exposure light quantity supervising method being adaptable to an apparatus for evaluating characteristics of a photosensitive drum for use in electrophotography, said method comprising the steps of:

• providing a second illuminance measuring probe in addition to said first illuminance measuring probe;
• applying the same quantity of light to said first and second illuminance measuring probes via said reflecting mirror;
• and
• detecting the change in the angle of said reflecting mirror the above-described accommodating space lb. As a result, by utilizing a fact that the quantity of light applied to said first illuminance measuring probe and that applied to said second illuminance measuring probe become different from each other if said angle of said reflecting mirror is changed.

An apparatus for use in electrophotography, said apparatus comprising:

• a process drive portion;
• an exposure light source portion;
• a control portion;
• and
• a case which accommodates said elements in a same shielding space thereof, wherein
• said space in said case is divided into three sections in order to prevent introduction of external light and light transmitted from said exposure light source portion into at least said process drive portion such that a lowermost accommodating space of said three sections accommodates said control portion, an intermediate accommodating space of said three sections accommodates said process drive portion and an uppermost accommodating space of said three sections accommodates said exposure light source portion;
• an air transmission device and an exhaust pipe opened to the outside are provided for said exposure light source portion;
• and
• an exhaust device is provided for said control portion, wherein
• said process drive portion has a rotatable photosensitive drum having characteristics to be measured, and a charging portion and the like secured adjacent to said photosensitive drum and a potential measuring probe for measuring a surface potential, generated due to charge exposure, of said photosensitive drum and
• said potential measuring probe being fixed adjacent to a position of said photosensitive drum at which light irradiated onto said photosensitive drum by said exposure light source portion travels over a shortest distance, said drum being movable in a lengthwise direction of said photosensitive drum so that the surface potential of said photosensitive drum is measured by said potential measuring probe.