| 摘要 |
An apparatus in which the developability of electrostatically charged particles in a mixture of particulate material is measured. The apparatus includes a transparent member positioned closely adjacent to a developer roller of an electrophotographic printing machine. A brush of particles is formed adjacent the member in one mode of operation, while, in another mode of operation, a cloud of particles is formed adjacent the member. A portion of the charged portions are attracted to the member. A beam of energy is transmitted through the member with the internal angle of incidence being greater than the critical angle of incidence of the member. The intensity of the internally reflected beam is detected and a signal generated indicative of the quantity of charged particles adhering to the member. |
