Flow passage assembly and method for manufacturing flow passage assembly, inkjet recording head, and recording apparatus

A method for manufacturing a flow passage assembly, comprising:

• forming a first flow passage in a first joint interface formed by welding a first surface of a first flow passage forming member to a first surface of a second flow passage forming member using an ultrasonic welding process;
• and
• forming, after the first flow passage is formed, a second flow passage in a second joint interface formed by welding a first surface of a third flow passage forming member to one of a second surface of the first flow passage forming member and a second surface of the second flow passage forming member using an ultrasonic welding process,
• wherein an area per unit length of a weld portion used when the first flow passage is formed is greater than an area per unit length of a weld portion used when the second flow passage is formed,
• wherein one of the two flow passage forming members that form each of the first joint interface and the second joint interface has a protruding welding rib formed thereon,
• wherein the welding rib is welded using the ultrasonic welding process, and wherein a volume of the welding rib located in the first joint interface is greater than a volume of the welding rib located in the second joint interface.

A flow passage assembly comprising:

• a first flow passage forming member;
• a second flow passage forming member joined to the first flow passage forming member using an ultrasonic welding process, the second flow passage forming member having at least one first flow passage in a first joint interface formed between a first surface of the first flow passage forming member and a first surface of the second flow passage forming member;
• and
• a third flow passage forming member joined to a second surface of the second flow passage forming member opposite to the first joint interface using an ultrasonic welding process, the third flow passage forming member having at least one second flow passage in a second joint interface formed between the second surface of the second flow passage forming member and the third flow passage forming member;
• wherein a total area of weld portions used when the first flow passage is formed is greater than a total area of weld portions used when the second flow passage is formed,
• wherein one of the two flow passage forming members that form each of the first joint interface and the second joint interface has a protruding welding rib formed thereon,
• wherein the welding rib is welded using the ultrasonic welding process, and wherein a volume of the welding rib located in the first joint interface is greater than a volume of the welding rib located in the second joint interface.

A flow passage assembly comprising:

• a first flow passage forming member;
• a second flow passage forming member joined to the first flow passage forming member using an ultrasonic welding process, the second flow passage forming member having at least one first flow passage in a first joint interface between a first surface of the first flow passage forming member and a first surface of the second flow passage forming member;
• and
• a third flow passage forming member joined to a second surface of the second flow passage forming member using an ultrasonic welding process, the third flow passage forming member having at least one second flow passage in a second joint interface formed between the second surface of the second flow passage forming member and the third flow passage forming member;
• wherein an area per unit length of a weld portion generated when the first flow passage is formed is greater than an area per unit length of a weld portion generated when the second flow passage is formed,
• wherein one of the two flow passage forming members that form each of the first joint interface and the second joint interface has a protruding welding rib formed thereon,
• wherein the welding rib is welded using the ultrasonic welding process, and wherein a volume of the welding rib located in the first joint interface is greater than a volume of the welding rib located in the second joint interface.

A method for manufacturing a flow passage assembly, comprising:

• forming a first flow passage in a first joint interface formed by welding a first surface of a first flow passage forming member to a first surface of a second flow passage forming member using an ultrasonic welding process;
• and
• forming, after the first flow passage is formed, a second flow passage in a second joint interface formed by welding a first surface of a third flow passage forming member to one of a second surface of the first flow passage forming member and a second surface of the second flow passage forming member using an ultrasonic welding process,
• wherein one of the two flow passage forming members that form each of the first joint interface and the second joint interface has a protruding welding rib formed thereon,
• wherein the welding rib is welded using the ultrasonic welding process, and
• wherein a volume of the welding rib located in the first joint interface is greater than a volume of the welding rib located in the second joint interface.