| 摘要 |
1,223,741. Electro-photographic apparatus. RICOH K. K. March 20, 1968 [March 27, 1967], No.13532/68. Heading G2H. In an electro-statographic duplicator, using a dry developer, (coloured toner particles mixed with iron filings), a device, shown in Fig.3 for detecting the density of the toner comprises a tape 8 having a surface to which the toner adheres, means for moving the tape past a developing roller 5, and photo-electric means 12 for detecting the density of toner adhering to the tape. The tape may be charged by a corona discharger 10 so that toner particles adhere by electrostatic attraction, or may be coated with a weak adhesive. Light source 11 and photo-element 12 are on opposite sides of the tape if the latter is light pervious and on the same side if the tape is of light reflective material. In another embodiment Fig. 4 (not shown), an endless tape (18) is used and the toner is removed by a plate (20) after the tape has passed the photoelement (12). The output of the photo-element may operate a device for automatically supplying toner to the developer tank 1 when the quantity of toner becomes less than a predetermined quantity. |
