Patent ID: 6726318
Filing Date: 2004-04-27
Classification: B41J

Abstract:
A microscopic droplet detecting device for detecting a passage of droplets jetted from a nozzle of an ink jetting device, comprising:a droplet detecting section including a paired light emitting and receiving elements which are arranged such that the light emitting element emits a light flux so as to cross a traveling course of the droplets jetted from the nozzle and the light receiving element receives a detecting light flux among the emitted light flux, wherein a detecting area of the detecting light flux corresponds to a light receiving area of the light receiving element; a jet control section to control the ink jetting device to jet droplets serially along the traveling course in such a way that serial droplets simultaneously exist in a form of group in the detecting area of the detecting light flux so that the droplet detecting section detects the group of serial droplets and outputs an output signal representing the group of serial droplets; and a jetting condition detecting section to detect a jetting condition of the nozzle based on the output signal; wherein the jet control section controls the ink jetting device to jet plural groups of serial droplets so as to satisfy the following formula: &bgr;&gE;L/V where&bgr; is a suspension time period (m sec) between a preceding group of serial droplets and a following group of serial droplets, L is a distance (m) of the detecting area of the detecting light flux along the traveling course of droplets, and V is a speed (m/sec) of a droplet when the droplet passes over the detecting area of the detecting light flux.