EP0718102A2
Expired / Lapsed
EP
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Compact ink jet head with deformable structure for ink discharge with great force
Assignee: Sharp Corp
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Filing: 1995-05-30
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Granted: —
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Expires: 2015-05-30
Abstract
Abstract An ink jet head (10), having a long life, capable of discharging ink with a strong force and at a high speed is provided at small size. A container (6) comprises a casing (5) and a nozzle plate (7) covering the upper surface of the casing (5) and having an ink discharge opening (7a). A buckling structure (1) is fixed at its both longitudinal ends to the bottom surface of the container (6) via an installing member (3) and its center portion can be deformed upward by buckling. A diaphragm (2) is positioned above the buckling structure (1) with a space therebetween and placed on an inner wall of the casing (5) with its periphery fixed thereto so as to liquid-tightly partition the inside of the container (6) into a space on the structure-provided side and an ink chamber and deformable upward. A connection member (4) connects the diaphragm (2) and the buckling structure (1) at their center. Electrode (1a, 1b) are provided at both end of the buckling structure (1) to generate thermal stress therein by supplying electric current for buckling and consequently to apply pressure to ink (100) in the ink chamber for discharging.
Inventors
- 👤 Shingo Abe
- 👤 Tetsuya Inui
- 👤 Hirotsugu Matoba
- 👤 Susumu Hirata
- 👤 Masaharu Kimura
- 👤 Yorishige Ishii
- 👤 Hajime Horinaka
- 👤 Hiroshi Onda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 06:29
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/135; B41J2/14; B41J2002/14346
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
130 words
An ink jet head (10) comprising: a container (6) having an ink discharge opening (7a) on a wall (7) thereof; a structure (1) being deformable and having portions which form both ends thereof in at least one direction and which are fixed to a wall surface inside the container (6); a diaphragm (2) which keeps an ink chamber liquid-tightly and which is deformable toward the ink chamber and which is positioned above the deformable structure (1) with a space therebetween and which is connected at least partly with the deformable structure (1); and compression means (1a, 1b), provided in the container (6), for deforming the deformable structure (1) so as to discharge ink (100) in the ink chamber from the ink discharge opening (7a) by applying pressure to ink (100).
Claim 2
Dependent Claim
179 words
An ink jet head (10) comprising: a container having an ink discharge opening (7a) on a wall (7) thereof; a buckling structure (1) being deformable toward the ink discharge opening (7a) and having portions which form both ends thereof in at least one direction and which are fixed to a wall surface opposed to the wall (7) of the container (6); a diaphragm (2) which is positioned above the buckling structure (1) with a space therebetween and which liquid-tightly partitions the inside of the container (6) into a space on the buckling structureside and an ink chamber on the ink discharge openingside and which is deformable toward the ink chamber; a connection member (4) for connecting the diaphragm (2) and the buckling structure (1) with each other in the vicinity of the center thereof; and compression means (1a, 1b), provided in the space, for causing the buckling structure (1) to buckle by generating a compression load therein so as to discharge ink (100) in the ink chamber from the ink discharge opening (7a) by applying pressure to ink (100).
Claim 3
Dependent Claim
17 words
The ink jet head according to claim 2, wherein a plurality of connection members (4) is provided.
Claim 4
Dependent Claim
49 words
The ink jet head according to claim 2, wherein a plurality of rectangular strips project radially from the center of the buckling structure (11); and portions which form both ends of the diaphragm (2) in at least one direction are fixed to an inner wall of the container (6).
Claim 5
Dependent Claim
49 words
The ink jet head according to claim 3, wherein a plurality of rectangular strips project radially from a center of the buckling structure (11); and portions which form both ends of the diaphragm (2) in at least one direction are fixed to an inner wall of the container (3).
Claim 6
Dependent Claim
29 words
The ink jet head according to claim 2, wherein the diaphragm (2) is not connected with any members other than the buckling structure (1) via the connection member (4).
Claim 7
Dependent Claim
29 words
The ink jet head according to claim 3, wherein the diaphragm (2) is not connected with any members other than the buckling structure (1) via the connection member (4).
Claim 8
Dependent Claim
322 words
An ink jet head (10) comprising: a container (6) having an ink discharge opening (7a) on a wall (7) thereof; a buckling structure (1) comprising two or more pairs of rectangular strips which are radially projected straight from a center thereof, leading ends of which are fixed to a wall surface opposed to the wall (7) of the container (6) and which are deformable toward the ink discharge opening (7a); a diaphragm (2) which is positioned above the buckling structure with a space therebetween such that portions forming both ends in at least one direction are fixed to an inner wall of the container (6) so as to liquid-tightly partition inside of the container (6) into a space on a buckling structureside and an ink chamber on the ink discharge openingside (7a) and which is deformable toward the ink chamber; a connection member (4) for connecting the diaphragm (2) and the buckling structure (1) with each other at the center thereof; and compression means (1a, 1b), provided in the space, for causing the buckling structure (1) to buckle by generating thermal stress therein with supply of electric current, so that ink (100) is discharged from the ink discharge opening (7a) by applying pressure to the ink (100) in the ink chamber, wherein assuming that Young's modulus of each rectangular strip constituting the buckling structure (1) is E; the width thereof is b; the thickness thereof is h; the coefficient of linear expansion thereof is α; the length of a pair of rectangular strips is ℓ; the total number of pairs of rectangular strips is n; the temperature change in the buckling structure (1) at the time of buckling is t; and the spring constant of the diaphragm (2) is k, the thickness (h) of the rectangular strip satisfies an equation expressed below to generate a buckling energy: 2ℓ(-p)cos(u/3+4π/3)<h<2ℓ(-p)cos(u/3) where p=-αt/π 2 , q=3k/nEbπ 4 , u=cos -1 {q/p(-p) ½ } , 0≦u≦π
Claim 9
Dependent Claim
116 words
The ink jet head according to claim 8, wherein supposing that the surface tension of the ink (100) is σ; the viscosity coefficient thereof is µ: the mass of an ink droplet (100a) is m; the discharge speed thereof is v; the surface area thereof is S; the length of the ink discharge opening (7a) is L, the thickness (h) of the rectangular strip satisfies an equation expressed below to generate a buckling energy (U₁ - U₂) necessary for discharging the ink droplet (100a): U₁ - U₂ = (3nEbhℓ 2 αtπ 2 - nEbh 3 π 4 - 6ℓ 3 k) 2 /18nEbhℓ 3 π 4 > mv 2 /2 + σS + 8πµL 2 v
Claim 10
Dependent Claim
102 words
The ink jet head according to claim 9, wherein the thickness (h) of the rectangular strip is an optimum value hs expressed below to generate a maximum buckling energy necessary for discharging the ink droplet (100a): hs = ℓ{-s + (s 2 + r 3 ) ½ } 1/3 + ℓ{-s - (s 2 + r 3 ) ½ } 1/3 ; when s 2 + r 3 >0 ; hs = 2ℓ(-r)cos(w/3) ; when s 2 + r 3 < 0 where r = -αt/5π 2 , s = -3k/5nEbπ 4 , w = cos -1 {s/r(-r) ½ } , 0≦w≦π
Claim 11
Dependent Claim
356 words
An ink jet head comprising: a container (6) having an ink discharge opening (7a) on a wall (7) thereof; a buckling structure (1) comprising two or more pairs of rectangular strips which are radially projected straight from a center thereof, leading ends of which are fixed to a wall surface opposed to the wall (7) of the container (6) and which are deformable toward the ink discharge opening (7a); a diaphragm (2) which is positioned above the buckling structure (1) with a space therebetween such that portions forming both ends in at least one direction are fixed to an inner wall of the container (6) so as to liquid-tightly partition inside of the container (6) into a space on a buckling structureside and an ink chamber on the ink discharge openingside and which is deformable toward the ink chamber; a connection member (4) for connecting the diaphragm (2) and the buckling structure (1) with each other at the center thereof; and compression means (1a, 1b), provided in the space, for causing the buckling structure (1) to buckle by generating thermal stress therein with supply of electric current, so that ink (100) is discharged from the ink discharge opening (7a) by applying pressure to ink (100) in the ink chamber, wherein assuming that Young's modulus of each rectangular strip constituting the buckling structure (1) is E; the width thereof is b; the thickness thereof is h; the coefficient of linear expansion thereof is α; the entire length of a pair of rectangular strips is C; the effective length of a pair of rectangular strips excluding the center thereof is ℓ; the total number of pairs of rectangular strips is n; the temperature change in the buckling structure (1) at the time of buckling is t; and the spring constant of the diaphragm (2) is k, the width (b) of the rectangular strip is given by an equation shown below; and the effective length (ℓ) satisfies an equation expressed below to generate a buckling energy: b = (C-ℓ)/tan{(n-1)π/2n} (3nEbhℓ 2 αtπ 2 - nEbh 3 π 4 - 6ℓ 3 k) 2 /3nEbhℓ 3 π 4 > 0
Claim 12
Dependent Claim
108 words
The ink jet head according to claim 11, wherein supposing that the surface tension of the ink (100) is σ; the viscosity coefficient thereof is µ: the mass of an ink droplet (100a) is m; the discharge speed thereof is v; the surface area thereof is S; the length of the ink discharge opening (7a) is L, the effective length (ℓ) satisfies an equation expressed below to generate a buckling energy (U₁ - U₂) necessary for discharging the ink droplet: (3nEbhℓ 2 αtπ 2 - nEbh 3 π 4 - 6ℓ 3 k) 2 /18nEbhℓ 3 π 4 > mv 2 /2 + σS + 8πµL 2 v
Claim 13
Dependent Claim
52 words
The ink jet head according to claim 12, wherein the effective length (ℓ) satisfies an equation expressed below to generate a maximum buckling energy necessary for discharging the ink droplet (100a): d{(3nEbhℓ 2 αtπ 2 - nEbh 3 π 4 - 6ℓ 3 k) 2 /18nEbhℓ 3 π 4 }/dℓ = 0
References Cited (Backward Citations)
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