| 摘要 |
1483471 Toner concentration sensing ADDRESSOGRAPH MULTIGRAPH CORP 6 Nov 1974 [3 Dec 1973] 48048/74 Headings G2H and G3R A toner concentration sensing means comprises a sensing member which is developed and cleaned independently of the latent image. A magnetic brush developer contacts a driven, rotary, relatively narrow sensing wheel having an optical read head 20 positioned to detect changes in toner concentration by intensity of reflected light. The sensing wheel is made up of three parts 22, 23, 24 which are separated by insulations 26 and which are connected to different electrical potentials to simulate an image pattern. Light emitted from a source 30 in head 20 is reflected from toner covered part 23 and sensed by photo-sensor 36. Part 23 is cleaned by reversing the polarity thereon. Cleaning and developing of part 23 occurs an odd number of times in each revolution of the wheel. In a second embodiment an insulating material is used for the magnetic brush and the outer parts 22 and 24 are used in a similar manner to part 23. Circuitry is provided to compare the difference between the signals from the developed part 23 and cleaned part 23, with a reference signal for an ideal image. |
