| 摘要 |
1291758 Electro-physical measurements R C A CORPORATION 30 Sept 1970 [9 Oct 1969] 46511/70 Heading G1N [Also in Division G2-3] A magnetic brush arrangement comprising a stationary magnet 30 and rotary cylinder 32 spaced from a stationary magnet 54 applies toner particles to an image bearing web 16, and a doctor blade 56 removes magnetic carrier particles and excess toner from the cylinder 32. The current drawn by constant speed motor 47 driving cylinder 32 is used as an indication of the force on the magnetic brush 28 and on the scraper blade 56. As the force increases (i.e. as toner is removed) motor 47 has to draw more current to maintain its speed. A meter relay 103 closes a switch 105 to energize lamp 60 and motor 90 when the current reaches a predetermined value. If the current increases above this value, indicating that hopper 96 is empty, relay 103 switches off motor 47. |
