| 摘要 |
<p>An optical drop detect circuit for a thermal ink jet printer. The optical drop detect circuit includes an optical sensor (17) for providing an electrical output indicative of a presence of an ink drop, a transconductance amplifier (21) responsive to the output of said optical sensor, first and second cascaded bandpass amplifiers (23, 25) responsive to the transconductance amplifier, a first comparator circuit (31, 41) responsive to the output of the cascaded bandpass amplifiers for providing an output pursuant to optical sensing of a first minimum ink drop size, and a second comparator circuit (32, 42) responsive to the output of the cascaded bandpass amplifiers for providing an output pursuant to optical sensing of a second minimum ink drop size. <IMAGE></p> |
