Liquid discharge head

1 . A liquid discharge head comprising:

a discharge port through which a liquid is discharged;

an element for discharging the liquid from the discharge port;

a channel through which the liquid is supplied to the discharge port; and

a film member that is provided so as to be in contact with the liquid in a liquid chamber in the channel,

wherein the film member has a corrugated structure in which a plurality of loop-shaped projecting portions and a plurality of loop-shaped recessed portions are alternately formed, and

wherein, when seen in a direction perpendicular to a plane of the film member, the corrugated structure has a loop shape having at least one linear portion.

2 . The liquid discharge head according to claim 1 , further comprising:

an element substrate including the discharge port and the element; and

a liquid supply unit including the film member and a channel forming member that includes the channel and the liquid chamber.

3 . The liquid discharge head according to claim 2 ,

wherein the film member defines a part of a surface of the liquid chamber, and

wherein, when a volume of the liquid chamber increases, a surface of the film member surrounded by the corrugated structure moves in a direction separating from a surface of the liquid chamber facing the film member, and, when the volume of the liquid chamber reduces, the surface of the film member surrounded by the corrugated structure moves in a direction approaching the surface of the liquid chamber.

4 . The liquid discharge head according to claim 2 ,

wherein the film member is interposed between the channel forming member and a cover member.

5 . The liquid discharge head according to claim 4 ,

wherein the cover member has a communicating port for communication of a space between the film member and the cover member with an atmosphere.

6 . The liquid discharge head according to claim 4 ,

wherein, when seen in a direction parallel to the plane of the film member, the cover member has a sectional shape that projects toward a surface of the cover member opposite from the film member.

7 . The liquid discharge head according to claim 2 ,

wherein the channel forming member includes, in the liquid chamber surrounded by the channel forming member and the film member, a filter that collects foreign matter in the channel.

8 . The liquid discharge head according to claim 2 ,

wherein the channel forming member includes a supply channel through which the liquid is supplied to the discharge port and a flow-out channel through which the liquid flows out from the discharge port, and

wherein the liquid in the liquid chamber circulates.

9 . The liquid discharge head according to claim 8 ,

wherein the channel forming member further includes a bypass channel that directly connects the supply channel and the flow-out channel to each other.

10 . The liquid discharge head according to claim 2 ,

wherein the channel includes a supply channel through which the liquid is supplied to the element substrate and a flow-out channel through which the liquid flows out from the discharge port, and

wherein the liquid circulates between an inside and an outside of the element substrate.

11 . The liquid discharge head according to claim 1 ,

wherein the film member is formed of polyimide or polyetherether ketone.

12 . The liquid discharge head according to claim 1 ,

wherein the at least one linear portion includes four linear portions, and

wherein, when seen in the direction perpendicular to the plane of the film member, the corrugated structure has a rounded rectangular shape having the four linear portions and four curved portions.

13 . The liquid discharge head according to claim 1 ,

wherein, when seen in a direction parallel to the plane of the film member, a height of the corrugated structure is greater than or equal to 0.2 mm and smaller than or equal to 3.0 mm.

14 . The liquid discharge head according to claim 1 ,

wherein the element is a piezoelectric element.

15 . A liquid discharge apparatus comprising:

a liquid discharge head including

a containing section that contains a liquid,

a discharge port to which the liquid is supplied from the containing section and through which the liquid is discharged,

an element for discharging the liquid from the discharge port,

a channel through which the liquid is supplied to the discharge port, and

a film member that is provided so as to be in contact with the liquid in a liquid chamber in the channel,

wherein the film member has a corrugated structure in which a plurality of loop-shaped projecting portions and a plurality of loop-shaped recessed portions are alternately formed, and

wherein, when seen in a direction perpendicular to a plane of the film member, the corrugated structure has a loop shape having a linear portion.