Patent ID: 8083322

Claim:
A liquid discharge head comprising: a plurality of discharge ports for discharging a liquid; a plurality of electrothermal transducers disposed on a substrate and for generating heat energy to be used for discharging the liquid; a plurality of bubble generation chambers, each of the electrothermal transducers being provided within one of the bubble generation chambers; and a plurality of discharge-port portions causing the discharge ports to communicate with the bubble generation chambers, the discharge-port portions each including a first discharge-port section continuing from a corresponding one of each of the discharge ports and a second discharge-port section causing the first discharge-port section to communicate with a corresponding one of the bubble generation chambers, wherein a cross-sectional area parallel to a main surface of the substrate in each of the second discharge-port sections is greater than that of the first discharge-port sections, and less than that of the bubble generation chambers, wherein lengths of the cross-sections of each of the second discharge-port sections and the bubble generation chambers, in a direction perpendicular to a direction of arrangement of the plurality of discharge ports, are longer than lengths thereof in the direction of arrangement, and wherein the ratio of the length in the direction perpendicular to the direction of arrangement to the length in the direction of arrangement in the cross-section of each of the second discharge-port portions is greater than the ratio of a length in the direction perpendicular to the direction of arrangement to a length in the direction of arrangement in the cross-section of each of the first discharge-port portions.