Manufacturing method of liquid ejection head

A manufacturing method of a liquid ejection head including manufacturing a flow path constituting member for supplying a liquid to a plurality of an ejection module, the manufacturing of the flow path constituting member including using a metal mold which is constituted of a fixed mold and a movable mold, and the ejection module being configured to eject the liquid,

• the manufacturing of the flow path constituting member comprising:
• a first step of molding a first member, a second member, and a third member independently at locations different from each other in the metal mold by clamping the metal mold and injecting a resin to an inside of the metal mold, the first member, the second member, and the third member constituting the flow path constituting member;
• a second step of joining the first member and the second member by injecting a first sealing resin to a first contacting portion, the first contacting portion being formed by contacting the first member and the second member with each other by clamping the metal mold after opening the metal mold and sliding the movable mold to a position at which the first member retained at the movable mold and the second member retained at the fixed mold are opposite to each other;
• and
• a third step of joining the second member and the third member by injecting a second sealing resin to a second contacting portion, the second contacting portion being formed by contacting the second member and the third member with each other by clamping the metal mold after opening the metal mold and sliding the movable mold to a position at which the second member retained at the movable mold and the third member retained at the fixed mold are opposite to each other,
• wherein the first, second, and third steps are performed in this order,
• wherein the first sealing resin and the second sealing resin are respectively injected from different positions of the fixed mold,
• wherein in the third step, the second sealing resin is injected from a gate provided in the fixed mold in a position opposed to a center in a latitudinal direction of the third member,
• wherein in the first step, the first to third members are respectively formed in a rectangular plate shape,
• wherein the third step includes, after bringing the second member and the third member into contact with each other, sliding at least a part of a die member of the fixed mold that retains the third member, forming a space communicating with the gate between the die member and the third member, and injecting the second sealing resin from the space that was formed,
• wherein in the third step, a passage communicating with the space is formed in the second contacting portion, and the second member and the third member are joined by filling the second sealing resin in the passage, and
• wherein a projection projecting toward the third member and extending in parallel to the passage is formed in the die member.