| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a laser beam printer capable of using a triac small in current rating by suppressing the rush current of a heater, thereby attaining the reduction of cost. <P>SOLUTION: A heater power source circuit 30 is constituted of: a photo-triac 31 acting in response to input of a heater on/off signal from a system control circuit 18; a triac 32 provided between both electrodes of an AC power source through a fuse; and a varistor 33 connected in parallel with the triac 32. The photo-triac 31 is connected to the gate of the triac 32 and acts according to the heater on/off signal so as to switch the gate current of the triac 32. The triac 32 switches and controls an AC current input in an AC/DC converter 40 according to the switched gate current. The varistor 33 restrains the rush current of the heater to lighten load on the triac 32. <P>COPYRIGHT: (C)2008,JPO&INPIT |
