US 6,059,393 A · Driving method for an ink ejection device to enlarge print dot diameter

Abstract

In order to enlarge print dot diamter and to obtain an excellent print quality, two droplets are ejected successively at different speeds so that the two droplets merge before individually impinging against a sheet of paper. To this end, a first pulse signal A is applied to an actuator to thereby eject a first droplet at a first speed and thereafter a second pulse signal B is applied thereto to thereby eject a second droplet at a second speed faster than the first speed. The two droplets are merged during flying and the merged droplet forms a print dot on the sheet of paper. The print dot obtained when the flight time was shorter than 100 .mu.sec is larger by 20% than that obtained when the flight time was longer than 100 .mu.sec. The flight time can be adjusted by changing a time difference between the falling edges of the first and second pulse signals A and B.

Claims16

Dependent claims

A method of driving an ink ejection device that includes walls defining an ink channel, the ink channel having a volume filled with ink and having a length defined by two ends, a nozzle plate attached to one end of the ink channel and formed with a nozzle, an actuator coupled to each of the walls for changing the volume of the ink channel, and control means for applying pulse signals to the actuator, the method comprising the steps of:

(a) applying a first pulse signal to the actuator, causing ejection of a first ink droplet from the nozzle at a first speed;
and
(b) after ejection of the first ink droplet, applying a second pulse signal to the actuator, causing ejection of a second ink droplet from the nozzle at a second speed faster than the first speed so that the second ink droplet merges with the first ink droplet before individually impinging against a recording medium held in a predetermined position and that a merged ink droplet impinges against the recording medium within 100 .mu.sec of merger, whereby a diameter of a point dot on the recording medium is substantially maximized for a given volume of ink.

(a) applying a first pulse signal to the actuator, causing ejection of a first ink droplet from the nozzle at a first speed;
and
(b) after ejection of the first ink droplet, applying a second pulse signal to the actuator, causing ejection of a second ink droplet from the nozzle at a second speed faster than the first speed so that the second ink droplet merges with the first ink droplet prior to impingement of the first ink droplet on a recording medium, a merged ink droplet being deformed to have a cross-sectional area in a direction perpendicular to a direction in which the merged ink droplet travels, wherein a flight time of the merged ink droplet from merger to impingement on the recording medium is less than 100 .mu.sec so that the cross-sectional area of the merged ink droplet is larger than a reference cross-sectional area of the merged ink droplet when the merged ink droplet is substantially formed in a spherical shape to maximize a diameter of a point dot on the recording medium for a given volume of ink.

Dependencies are inferred from the claim text.

Driving method for an ink ejection device to enlarge print dot diameter

Life of this patent

Driving method for an ink ejection device to enlarge print dot diameter

Life of this patent

Abstract

Claims16