Patent ID: 7320513

Claim:
A bubble-ink jet print head comprising: a substrate having ink chambers to store ink and resistance heat emitting bodies to heat ink disposed thereover; and an ink supply passage which penetrates the substrate, extends beyond the substrate, and which is connected to the ink chambers, the ink supply passage including: a first trench formed at a first surface of the substrate in a first pattern having a separating distance from at least one of inlets of the ink chambers and connecting portions between the adjacent ink chambers, the first surface of the substrate having the ink chambers disposed thereover, and a second trench formed at a second surface of the substrate in a second pattern, having an area equal to or smaller than that of the first trench in the range of the first pattern of the first trench, having a uniform width, penetrating the substrate and directly connected to the first trench, wherein the first trench has a depth from 5 μm to 20 μm.