| 摘要 |
1,180,604. Fixing electrostatic images. RANK XEROX Ltd. May 1, 1967 [May 2, 19661, No. 20136/67. Heading G2H. An apparatus for fixing electrostatic toner particles 32 on record cards 2 comprises belts 30 which feed the cards successively past a photocell 35, which detects the leading edges of successive cards. The photo-cell normally receives light from a lamp 8. A second belt 30 feeds the card under a reflector of a lamp 40, e.g., a scanon gas lamp which is triggered on and off to effect fusing. Before the photo-cell 35 detects the leading edge of a card a flip-flop 46 is in reset condition, and so, through transistors 52 and 60, causes a normally unearthed plate of a capacitor 58 to be earthed, thus preventing charging. When the light path is interrupted, the photo-cell 35 feeds a signal through amplifier 44 to trigger flipflop 46 to set condition, such that the earthed plate of the capacitors 58 becomes unearthed and charging commences. As a result, a transistor 76 conducts when the charge on the capacitor is approximately half the voltage between the collector and base electrodes of the transistor. Capacitor 58 discharges through the primaly winding of a transformer 78 to trigger lamp 40. A time delay circuit having delay related to the speed of belts and comprising a capacitor 84 and resistor 82 causes a further charging cycle of capacitor 58 and triggering of lamp 40 before AND gate 80 resets flipflop 46. |
