US 12,076,987 B2
Liquid ejection head substrate, liquid ejection head, and method of manufacturing liquid ejection head substrate
Takeru Yasuda, Kanagawa (JP); Koichi Omata, Kanagawa (JP); and Yuzuru Ishida, Kanagawa (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Aug. 22, 2022, as Appl. No. 17/892,419.
Claims priority of application No. 2021-159098 (JP), filed on Sep. 29, 2021.
Prior Publication US 2023/0095423 A1, Mar. 30, 2023
Int. Cl. B41J 2/14 (2006.01); B41J 2/16 (2006.01)
CPC B41J 2/14129 (2013.01) [B41J 2/1631 (2013.01); B41J 2202/16 (2013.01); B41J 2202/22 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A liquid ejection head substrate comprising:
a base layer;
a heating resistance element provided over the base layer to generate a heat energy for ejecting a liquid;
a first insulation layer covering the heating resistance element; and
a protective layer provided on the first insulation layer, having a first region which overlaps the heating resistance element via the first insulation layer and a second region which does not overlap the heating resistance element, the protective layer is formed of a material including a metal which is eluted by an electrochemical reaction,
wherein the liquid ejection head substrate further comprises a second insulation layer provided over a region overlying the base layer where the protective layer is not provided and over the second region of the protective layer, and
wherein a layer thickness of the first insulation layer in a region uncovered with the protective layer is smaller than a layer thickness of the first insulation layer in a region covered with the protective layer.