Patent ID: 7866785

Claim:
A droplet-ejection detecting device for detecting ejection of droplets from a plurality of nozzle orifices, comprising: a beam scanning mechanism which scans a plurality of droplet ejection lines along which droplets ejected from the nozzle orifices fly, by emitting a beam to intersect the droplet ejection lines, thereby subjecting the droplets to irradiation with the beam; a light receiving unit which receives light obtained as a result of the irradiation; and an ejection determining mechanism which determines safe ejections of the droplets from the nozzle orifices based on a received-light signal output from the light receiving unit, wherein the scanning is executed over a plurality of cycles in each of which the timing of the scanning and the timing of the ejection of the droplets are controlled in a timed relation to each other, the timed relation being varied between successive scanning cycles, and the election determining mechanism determines safe ejections of the droplets from the nozzle orifices based on received-light signals obtained by the plurality of cycles of scanning.