Nozzle substrate, ink-jet print head, and method for producing nozzle substrate

A nozzle substrate, comprising:

• a main substrate including a first surface and a second surface;
• an oxidation film formed on the second surface of the main substrate;
• and
• a water repellent film formed on a surface of the oxidation film, wherein
• the surface of the oxidation film is at an opposite side to a main substrate side of the oxidation film,
• the nozzle substrate includes a nozzle hole that penetrates in a thickness direction of the nozzle substrate,
• the nozzle hole includes a first through hole that penetrates the main substrate in the thickness direction, a second through hole that penetrates the oxidation film and being connected to the first through hole, and a third through hole that penetrates the water repellent film and being connected to the second through hole,
• the first through hole includes a recessed part formed on the first surface of the main substrate and a hole penetrating a bottom wall of the recessed part of the main substrate,
• the recessed part has a truncated cone shape whose transverse section is gradually reduced from the first surface of the main substrate to an oxidation film side of the main substrate,
• the nozzle hole includes an ink ejecting path,
• the ink ejecting path includes the hole, the second through hole, and the third through hole,
• the ink ejecting path has a solid cylindrical shape, and
• an inner circumference surface of the second through hole and an inner circumference surface of the third through hole are approximately flush.