Ink-jet recording head and its use

Claim 2

An ink-jet recording head especially according to claim 1, comprising: a central substrate (1) that is polarized (E₁) in the direction of its thickness and that has, on both surfaces, grooves (3, 4) spaced by diaphragms (5, 6) at a predetermined pitch and electrodes (17, 18) that are formed in those grooves (3, 4) in an electrically isolated manner each of said grooves (3, 4)comprising a portion (b) having a sufficient depth to form an ink reservoir, a portion (a) communicating with one side (1a) of the head and having a sufficient depth to provide an orifice (50, 51) that is adapted to squirt ink drops, and a portion (c) having a depth appropriate for receiving an externally supplied ink; two piezoelectric substrates (20, 30) that are polarized (E₂, E₃) in the direction of their thickness and each of which has, on one surface, grooves (21, 31) spaced by diaphragms (23, 33) at a predetermined pitch and electrodes (24, 34) that are formed in those grooves (21, 31) in an electrically isolated manner, each of said grooves (21, 31) comprising a portion (b) having a sufficient depth to form an ink reservoir, a portion (a) communicating with one side of the head and having a sufficient depth to provide an orifice that is adapted to squirt ink drops, and a portion (c) having a depth appropriate for receiving an externally supplied ink; said two substrates (20, 30) being fixed to said central substrate (1) to form a unitary assembly in such a way that the surfaces of those substrates where the grooves are open are aligned with those surfaces of the central substrate where the grooves are open and that the directions (E₂, E₃) of polarization in said two substrates (20, 30) are opposite to the direction of polarization (E₁) in the central substrate (1), said recording head further including an ink supply (10) means that is provided on the side opposite to the side where said orifice (50, 51) is to be provided.

Claim 3

An ink-jet recording head according to claim 2, wherein the grooves (3) formed in one surface of said central substrate (1) are offset from the grooves (4) in the other surface by one half of the pitch between adjacent grooves.

Claim 4

An ink-jet recording head comprising: a substrate unit (142) that is composed of a first and a second polarized piezoelectric substrate (140, 141) that are bonded together in such a way that the directions of polarization are opposite to each other, said substrate unit having a plurality of grooves (143) formed therein that are spaced by diaphragms (146) at a predetermined pitch and electrodes (147) that are formed in those grooves (143) in an electrically isolated manner, each of said grooves (143) comprising a portion (143b) that extends from the surface of the first piezoelectric substrate (141) to partial thickness of the second piezoelectric substrate (140) and that has a sufficient depth to form an ink reservoir, a portion (143a) communicating with one side of the first piezoelectric substrate (141) and having a sufficient depth to provide an orifice that is adapted to squirt ink drops, and a portion (143c) having a depth appropriate for receiving an externally supplied ink; a top cover (150) that seals the surface of said substrate unit where the grooves are open; and a member (151) for supplying ink into said grooves.

Claim 5

An ink-jet recording head according to claim 4, wherein said first piezoelectric substrate (141) has a thickness approximately one half the depth of the ink reservoir portion.

Claim 6

An ink-jet recording head comprising: a substrate unit that is composed of a first (201), a second (200) and a third (202) polarized piezoelectric substrate that are bonded together in such a way that the directions of polarization are opposite to each other, said substrate unit having a plurality of grooves (203, 204) formed therein that are spaced by diaphragms at a predetermined pitch and electrodes that are formed in those grooves in an electrically isolated manner, each of said grooves comprising a portion that extends from the surface of the outer first (201) and third (202) piezoelectric substrates to a partial thickness of the centrally fixed second piezoelectric substrate (200) that has a sufficient depth to form an ink reservoir, a portion communicating with one side of the first piezoelectric substrate and having a sufficient depth to provide an orifice that is adapted to squirt ink drops, and a portion having a depth appropriate for receiving an externally supplied ink; two covers (205, 206) that seal the opposite surface of said substrate unit where the grooves are open; and a member (207, 208) for supplying ink into said grooves.

Claim 7

An ink-jet recording head according to claim 6, wherein said first (201) and third (202) piezoelectric substrates have a thickness approximately one half the depth of the ink reservoir portion.

Claim 8

An ink jet recording head according to claim 6 or 7, wherein the grooves formed in one surface of said second substrate are offset from the grooves in the other surface by one half of the pitch between adjacent grooves.

Claim 9

An ink-jet recording head comprising: a substrate unit that is composed of a first (171) and a second (170) polarized piezoelectric substrate that are bonded together in such a way that the directions of polarization are opposite to each other, said substrate unit having a plurality of grooves (173) formed therein that are spaced by diaphragms at a predetermined pitch and electrodes that are formed in those grooves in an electrically isolated manner, each of said grooves (137) extending from the surface of the first (171) piezoelectric substrate to a partial thickness of the second (170) piezoelectric substrate and having a sufficient depth to form an ink reservoir, said grooves being sealed at both ends; a top cover (180) that is fixed to the surface of said substrate unit where the grooves (180a) are open and that has grooves communicating with the grooves in said substrate unit to form nozzle orifices (181); and a member (182) for supplying ink into said grooves.

Claim 10

An ink-jet recording head according to claim 9, wherein said first piezoelectric substrate (171) has a thickness approximately one half the depth of the ink reservoir portion.

Claim 11

An ink-jet recording head especially according to claim 9 or 10 comprising: a substrate unit that is composed of a first, a second and a third polarized piezoelectric substrate that are bonded together in such a way that the directions of polarization are opposite to each other, said substrate unit having a plurality of grooves formed therein that are spaced by diaphragms at a predetermined pitch and electrodes that are formed in those grooves in an electrically isolated manner, each of said grooves extending from the surface of the outer first and third piezoelectric substrates to a partial thickeness of the centrally fixed second piezoelectric substrate and having a sufficient depth to form an ink reservoir, said grooves being sealed at both ends; two covers that are fixed to the opposite surface of said substrate unit where the grooves are open and that have grooves communicating with the grooves in said substrate unit to form nozzle orifices; and a member for supplying ink into said grooves.

Claim 12

An ink-jet recording head according to claim 11 wherein said first and third piezoelectric substrates have a thickness approximately one half the depth of the ink reservoir portion.

Claim 13

An ink-jet recording head according to one of the preceding claims, wherein each of said electrodes is divided into at least two regions (84, 85; 94, 95) in the longitudinal direction of the grooves (81; 91).

Claim 14

An ink-jet recording head according to one of the preceding claims wherein each of said electrodes (112, 122, 123) is formed in such a way that it is thin in the region closer to the nozzle orifice side and thick in the region closer to the ink supply side.

Claim 15

An ink-jet recording head according to one of the preceding claims, wherein said grooves (111, 130) are formed to be shallow (130b) in the region closer to the ink supply side so that the diaphragms (133) in the region closer to the nozzle orifice side will have a smaller elastic modulus.

Claim 16

Use of the ink-jet recording head in a printing apparatus.

Claim 17

A printing apparatus comprising an ink-jet recording head according to one of claims 1 to 15, a head carriage (303) for mounting said ink-jet recording head, head carriage driving means (304, 307) for driving said head carriage in a scanning direction, and a platen (308) on which a recording paper (309) is disposed.