Abstract: The light shielding member of the present disclosure includes an aluminum oxide ceramics including an oxide of titanium whose composition formula is shown as TiO2-x (1?x<2), and a total content of Fe, Ni, Co, Mn and Cr is 260 mass ppm or less.

Abstract: The light shielding member of the present disclosure includes an aluminum oxide ceramics including an oxide of titanium whose composition formula is shown as TiO2-x (1?x<2), and a total content of Fe, Ni, Co, Mn and Cr is 260 mass ppm or less.

Abstract: Provided is a channel member having a channel which penetrates from one main surface to the other main surface. The channel is formed with its diameter increased toward the other main surface from the one main surface. A parallel section which is substantially parallel to the other main surface and is exposed to the other main surface is provided on the inner surface of the channel.

Abstract: Provided is a channel member having a channel which penetrates from one main surface to the other main surface. The channel is formed with its diameter increased toward the other main surface from the one main surface. A parallel section which is substantially parallel to the other main surface and is exposed to the other main surface is provided on the inner surface of the channel.

Abstract: The ink delivery hole 11 of the support member 10 made of ceramics that supports the recording head 2 consists of the elongated hole 12 provided with the inclined bottom surface 13 that opens on the ink jet recording head side and deepens toward the center and the small-diameter hole 14 that communicates therewith, while surface roughness of at least the inclined bottom surface 13 of the ink delivery hole 11 is set in a range from 0.4 to 1.0 ?m in terms of arithmetic mean roughness (Ra) and the void ratio is set in a range from 5 to 30%. This constitution prevents bubbles, if ever entered, from staying in the ink delivery hole of the support member that supports the ink jet recording head, and enables it to stably discharge ink droplets of a predetermined quantity.

Abstract: The ink delivery hole 11 of the support member 10 made of ceramics that supports the recording head 2 consists of the elongated hole 12 provided with the inclined bottom surface 13 that opens on the ink jet recording head side and deepens toward the center and the small-diameter hole 14 that communicates therewith, while surface roughness of at least the inclined bottom surface 13 of the ink delivery hole 11 is set in a range from 0.4 to 1.0 m in terms of arithmetic mean roughness (Ra) and the void ratio is set in a range from 5 to 30%. This constitution prevents bubbles, if ever entered, from staying in the ink delivery hole of the support member that supports the ink jet recording head, and enables it to stably discharge ink droplets of a predetermined quantity.

Abstract: Provided is an alumina sintered body including not less than 99.3% by weight of Al2O3, not more than 0.25% by weight of SiO2, not more than 0.3% by weight of MgO, and not more than 0.3% by weight of CaO, and having a surface open porosity of less than 5%, and an average open pore diameter of not more than 5 &mgr;m. This alumina sintered body is applied to at least a surface exposed to ink in an ink jet recording head structure. This suppresses the elution of glass component of the alumina sintered body into ink, thereby stabilizing ink viscosity. This also suppresses falling of grains that causes clogging of ink discharge holes.