A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A printhead manufacturing method includes preparing a printing element substrate including a receiver, first and second input pads, and plural selection pads, and preparing a head substrate including first and second transmission lines. The receiver includes first and second terminals for receiving signals, and the first and second input pads are connected to the first and second terminals, respectively, and the plural selection pads connected to the second terminal via at least two from among plural resistive elements to selectively obtain one of plural combined resistances. At least one of the plural selection pads is selected to be connected to the first transmission line to obtain a value of the one of the plural combined resistances. The selected selection pad is connected to the first transmission line, the first input pad is connected to the first transmission line, and the second input pad is connected to the second transmission line.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A method for manufacturing a ball pen tip in which a spring for biasing a ball is assembled to the ball pen tip, the method including punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by a plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A method for manufacturing liquid ejection heads includes the steps of forming ejection port members on a substrate, the ejection port members each having a liquid channel and an ejection port for ejecting liquid through the channel, the liquid channel communicating with the substrate; forming supply ports passing through the substrate to supply liquid to the channels; and forming a separation groove in the substrate to separate the substrate for each liquid ejection head. The step of forming the ejection port members includes the step of hardening a material constituting the ejection port member by heat treatment. The step of forming the separation groove is performed before the step of hardening.

A nozzle plate for a fluid-ejection device, comprising: a first substrate made of semiconductor material, having a first side and a second side; a structural layer extending on the first side of the first substrate, the structural layer having a first side and a second side, the second side of the structural layer facing the first side of the first substrate; at least one first through hole, having an inner surface, extending through the structural layer, the first through hole having an inlet section corresponding to the first side of the structural layer and an outlet section corresponding to the second side of the structural layer; a narrowing element adjacent to the surface of the first through hole, and including a tapered portion such that the inlet section of the first through hole has an area larger than a respective area of the outlet section of the first through hole.

A method for manufacturing liquid ejection heads includes the steps of forming ejection port members on a substrate, the ejection port members each having a liquid channel and an ejection port for ejecting liquid through the channel, the liquid channel communicating with the substrate; forming supply ports passing through the substrate to supply liquid to the channels; and forming a separation groove in the substrate to separate the substrate for each liquid ejection head. The step of forming the ejection port members includes the step of hardening a material constituting the ejection port member by heat treatment. The step of forming the separation groove is performed before the step of hardening.