JP2012153071A - Inkjet head and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head that can hydrodynamically optimize ink supply.SOLUTION: The inkjet head 5 includes: a base body 21 in which a supply path 49 including a pressure chamber 31 communicating with a discharge hole 29a and a reservoir 27 communicating with the pressure chamber 31 is formed. In addition, the head 5 includes one or a plurality of blade-like parts 51 arranged in the supply path 49.

Description

  The present invention relates to an inkjet head and a recording apparatus.

  An ink jet head having a pressurizing chamber (cavity) communicating with a discharge hole and a reservoir communicating with the pressurizing chamber is known (for example, Patent Document 1). The space from the reservoir to the ejection hole is filled with ink. Then, when the volume of the pressurizing chamber changes and pressure is applied to the ink, the ink is sent from the pressurizing chamber to the ejection holes, and ink droplets are ejected from the ejection holes. The pressurizing chamber is replenished with ink from the reservoir.

JP-A-11-309877

  For the ink jet head configured as described above, various demands have arisen regarding fluid dynamics such as ink flow. For example, it is desired that the backflow from the pressurizing chamber to the reservoir is suppressed. In other words, it is desired to increase the flow path resistance between the pressurizing chamber and the reservoir. On the other hand, it is desired that ink is supplied from the reservoir to the pressurizing chamber promptly. In other words, it is desired to reduce the flow path resistance between the pressurizing chamber and the reservoir. Thus, conflicting demands have arisen in the inkjet head. It may be difficult to respond to such a request simply by changing the shape of the flow path.

  It is an object of the present invention to provide an ink jet head and a recording apparatus that can optimize ink supply hydrodynamically.

  An ink jet head according to an aspect of the present invention includes a base on which a flow path including a pressurizing chamber that communicates with a discharge hole and a reservoir that communicates with the pressurizing chamber is formed, and one or more disposed in the flow path. And a wing-shaped portion.

Preferably, the airfoil is arranged such that the chord is along the flow direction, and from the maximum blade thickness position where the blade thickness is the maximum blade thickness t _max in the chord direction to the edge on the pressure chamber side The relationship between the maximum length Lc and the length Lm from the maximum blade thickness position to the edge on the reservoir side is Lm <Lc.

Preferably, Lc <5.7 × t _max .

Preferably, Lm <1.9 × _tmax .

  Preferably, the plurality of wing-like portions are arranged apart from each other in the blade thickness direction.

  Preferably, a plurality of wing units in which a plurality of the wing-like portions are arranged apart from each other in the wing thickness direction are arranged at different positions in the flow direction, and each wing unit is in one wing unit. The position of the wing-like portion is different from the position of the wing-like portion in the other blade unit adjacent to the flow direction in the blade thickness direction.

  Preferably, a plurality of supply holes communicating with the plurality of pressurizing chambers are opened on the inner peripheral surface of the reservoir, and the plurality of supply holes in the reservoir are opened in the plurality of wing-shaped portions. In the position, the chord is arranged along the direction of the opening.

  A recording apparatus according to an aspect of the present invention includes an inkjet head and a control unit that controls the inkjet head, and the inkjet head includes a pressurizing chamber that communicates with an ejection hole and a reservoir that communicates with the pressurizing chamber. And a base body on which a flow path including the same is formed, and one or a plurality of wing-like portions disposed in the flow path.

  According to said structure, supply of an ink can be optimized hydrodynamically.

FIG. 3 is a perspective view schematically illustrating a main part of the recording apparatus according to the embodiment of the invention. FIG. 2 is a cross-sectional view of a part of an ink jet head of the recording apparatus of FIG. 1. FIG. 2 is a perspective plan view schematically showing a part of a flow path of an ink jet head of the recording apparatus of FIG. 1. 4A and 4B are schematic views showing wing-like portions provided in the inkjet head of FIG. FIG. 5A and FIG. 5B are schematic views for explaining the operation of the wing-like portion of FIG. 6 (a) and 6 (b) are diagrams for explaining a preferred shape of the wing-like portion of FIG. FIG. 7A and FIG. 7B are perspective views showing a specific arrangement example of the wing-shaped portion in the pressurizing chamber. FIG. 8A and FIG. 8B are perspective views showing a specific arrangement example of the wing-shaped portion in the reservoir. FIG. 9A and FIG. 9B are schematic views showing an example of the arrangement of the wing-like portions.

(Basic configuration of recording device)
FIG. 1 is a perspective view schematically showing a main part of a recording apparatus 1 according to an embodiment of the present invention.

  The recording device 1 and the inkjet head 5 to be described later may be either upward or downward, but hereinafter, for convenience, the orthogonal coordinate system xyz is defined and the z-direction normal direction is defined. The term “upper surface” or “lower surface” may be used with the side (upper side in FIG. 1) as the upper side.

  The recording apparatus 1 includes, for example, a transport unit 3 that transports a medium (for example, paper) 101 in a direction indicated by an arrow y1, a head 5 that ejects ink droplets toward the transported medium 101, and the transport unit 3 and the head. 5 and a control unit 7 for controlling the operation of 5.

  For example, the transport unit 3 transports a plurality of media 101 stacked on a supply stack (not shown) one by one to a discharge stack (not shown). The transport unit 3 may have a known appropriate configuration. In FIG. 1, the conveyance path is a straight path, and a conveyance unit provided with a roller 9 that contacts the medium 101 and a motor 11 that rotates the roller 9 is illustrated.

  The head 5 is disposed in the middle of the conveyance path of the medium 101 and faces the medium 101 from the positive side in the z direction. The head 5 may be a serial head that performs a shuttle motion in a direction (main scanning direction, x direction) orthogonal to the printing screen and the conveyance direction of the medium 101, or a line fixed (substantially) in the orthogonal direction. It may be a head. In the present embodiment, the case where the head 5 is a line head will be described as an example.

  The head 5 ejects and attaches ink droplets to the medium 101 at a plurality of positions in the x direction. By repeating this operation as the medium 101 is conveyed, a two-dimensional image is formed on the medium 101.

  The control unit 7 includes, for example, a CPU, a ROM, a RAM, and an external storage device. The controller 7 applies a desired voltage to the motor 11 by outputting a control signal to the motor driver 13 to control the motor 11. Similarly, the control unit 7 outputs a control signal to the head driver 15 to apply a desired voltage to the head 5 to control the head 5.

  FIG. 2 is a schematic cross-sectional view showing a part of the head 5 broken and enlarged. Note that the lower side of FIG. 2 is the side facing the medium 101.

  The head 5 is, for example, a piezo-type head that applies pressure to ink by mechanical strain of a piezoelectric element. The head 5 has a plurality of ejection elements 19 that eject ink droplets, and FIG. 2 shows one ejection element 19. The plurality of ejection elements 19 are arranged in the xy plane (see FIG. 3), and each ejection element 19 corresponds to one dot on the medium 101.

  In another aspect, the head 5 includes a base 21 that forms a space for storing ink, and an actuator 23 (partly used for the base 21) that applies pressure to the ink stored in the base 21. Have. The plurality of ejection elements 19 includes a base 21 and an actuator 23.

  A plurality of individual channels 25 (one is shown in FIG. 2) and a reservoir (common channel) 27 communicating with the plurality of individual channels 25 are formed inside the base 21. The individual flow path 25 is provided for each ejection element 19, and the reservoir 27 is provided in common for the plurality of ejection elements 19. Each individual flow path 25 includes a descender (partial flow path) 29 including a discharge hole 29 a facing the medium 101, a pressurization chamber 31 communicating with the descender 29, and a communication path 33 communicating the pressurization chamber 31 and the reservoir 27. And have. A part of the communication path 33 may have a cross-sectional area perpendicular to the ink flow direction smaller than that of the reservoir 27 and the pressurizing chamber 31 so that the communication path 33 functions as a squeezing.

  The plurality of individual flow paths 25 and the reservoirs 27 are filled with ink. When the volumes of the plurality of pressurizing chambers 31 change and pressure is applied to the ink, the ink is sent from the plurality of pressurizing chambers 31 to the plurality of descenders 29, and a plurality of ink droplets are ejected from the plurality of ejection holes 29a. Is discharged. In addition, the plurality of pressurizing chambers 31 are replenished with ink from the reservoir 27 via the plurality of communication paths 33.

  The cross-sectional shape or planar shape of the plurality of individual flow paths 25 and the reservoirs 27 may be set as appropriate. In the present embodiment, the pressurizing chamber 31 is formed to have a constant thickness in the z direction, and is a rhombus (see FIG. 3) having the x direction and the y direction as diagonal directions when viewed in the z direction. One corner of the rhombus in the y direction communicates with the descender 29, and the other corner communicates with the communication path 33. The communication path 33 is connected to the first supply hole 33 a that opens to the reservoir 27, the intermediate path 33 b that extends parallel to the xy plane from the first supply hole 33 a, and the intermediate path 33 b, and opens to the pressurizing chamber 31. And a second supply hole 33c. The cross-sectional shape of the reservoir 27 is, for example, a rectangle, and the first supply hole 33a opens on the upper surface of the rectangle.

  The base body 21 is configured, for example, by stacking a plurality of substrates. Specifically, the base body 21 includes a substrate 35 in which through holes constituting the plurality of individual flow paths 25 and the reservoirs 27 are formed, and a vibration plate 37 that closes the upper surface openings of the plurality of pressurizing chambers 31. Yes.

  The thickness and the number of layers of the plurality of substrates 35 may be appropriately set according to the shapes of the plurality of individual flow paths 25 and the reservoirs 27. The plurality of substrates 35 may be formed of an appropriate material, for example, formed of metal, ceramic, or silicon.

  The actuator 23 is composed of, for example, a unimorph type piezoelectric element that is displaced in a bending mode. Specifically, for example, the actuator 23 includes a diaphragm 37, a common electrode 39, a piezoelectric body 41, and a plurality of individual electrodes 43 that are stacked in order from the pressurizing chamber 31 side. The individual electrode 43 is provided for each ejection element 19.

  The diaphragm 37, the common electrode 39, and the piezoelectric body 41 are provided in common to the plurality of pressurizing chambers 31 so as to cover the plurality of pressurizing chambers 31, for example. On the other hand, the individual electrode 43 is provided for each pressurizing chamber 31. More specifically, the individual electrode 43 is generally similar to the pressurizing chamber 31 (generally rhombus in the present embodiment), and is slightly smaller than the width of the pressurizing chamber 31 and the corners of the individual electrode main body. And an extraction electrode 45 connected to the portion.

  The diaphragm 37, the common electrode 39, the piezoelectric body 41, and the plurality of individual electrodes 43 may be formed of an appropriate material. For example, the diaphragm 37 is made of ceramic, silicon oxide, or silicon nitride. The common electrode 39 and the plurality of individual electrodes 43 are made of, for example, platinum or palladium. The piezoelectric body 41 is made of ceramic such as PZT (lead zirconate titanate).

  The piezoelectric body 41 has a thickness direction (z direction) as a polarization direction. Accordingly, when a voltage is applied to the common electrode 39 and the individual electrode 43 to cause an electric field to act on the piezoelectric body 41 in the polarization direction, the piezoelectric body 41 contracts in the plane. Due to this contraction, the diaphragm 37 is bent so as to protrude toward the pressurizing chamber 31, and as a result, the volume of the pressurizing chamber 31 changes.

  The driving method of the ejection element 19 may be appropriately selected from known driving methods such as a pulling method and a pushing method. In addition, gradation may be expressed by increasing or decreasing the number of ink droplets for one dot recording or changing the amount of ink droplets. The start timing of driving the plurality of ejection elements 19 (applying pressure to the pressurizing chambers 31) may be the same as each other, or the flow path from the ejection holes 29a to the squeezing in the adjacent plural pressurizing chambers 31 The ink may be shifted from each other with a time difference shorter than the natural vibration period of the ink.

  FIG. 3 is a plan perspective view schematically showing a part of the flow path of the head 5. In FIG. 3, the pressurizing chamber 31 and the communication path 33 are indicated by solid lines, the first supply holes 33a are indicated by solid line circles, the descender 29 is indicated by a plurality of solid line circles, and the reservoir 27 is indicated by dotted lines. Has been. The descender 29 connected to one pressurizing chamber 31 is indicated by a plurality of circles, while the descender 29 changes its position in the x direction and the y direction from the pressurizing chamber 31 toward the discharge hole 29a. (Toward the negative side in the z direction).

  As described above, the plurality of pressurizing chambers 31 are arranged in the x direction and the y direction. The descender 29 is provided to change its position in the x direction and the y direction when moving from the pressurizing chamber 31 to the discharge hole 29a. Regarding the rows in which the pressurizing chambers 31 are arranged in the y direction, the relationship between the relative positions of the pressurizing chambers 31 and the discharge holes 29a connected to the pressurizing chambers 31 is the same in two adjacent rows. . In each row in which the pressurizing chambers 31 are arranged in the y direction, the descender 29 is provided so that the positions in the x direction of the discharge holes 29a connected to the pressurizing chambers 31 in each row are different from each other. . That is, in the head 5, a desired resolution (for example, 600 dpi) is realized in the x direction as a whole of the plurality of ejection holes 29a arranged in the x direction and the y direction.

  For example, the reservoir 27 extends in the x direction, and one pressurizing chamber 31 is provided for four rows arranged in the x direction. Although not particularly shown, the reservoir 27 is formed in a manifold shape, and has a main flow path and a plurality of sub flow paths branched from the main flow path. In FIG. 3, one sub flow path is illustrated. Show.

(Configuration for optimizing ink supply)
FIG. 4A is a schematic diagram showing a structure for optimizing the supply of ink hydrodynamically.

  One or a plurality of wing-like portions 51 are provided in the supply flow path 49 including the reservoir 27 and the pressurizing chamber 31 from the reservoir 27 to the pressurizing chamber 31. Each wing-like portion 51 is arranged along the direction of ink flow (the left-right direction in FIG. 4, the direction from the pressurizing chamber 31 side to the reservoir 27 side). The plurality of wing-like parts 51 are arranged in a direction intersecting with the ink flow direction to constitute a wing unit 53.

  The wing-like portion 51 may be provided in any one of the reservoir 27, the pressurizing chamber 31, and the communication passage 33 that communicates these, or may be provided in any two or all of them. FIG. 4A illustrates a case where the reservoir 27 and the pressurizing chamber 31 are provided.

  FIG. 4B is an enlarged view of the wing-like portion 51.

  The wing-like portion 51 has its wing thickness according to the position in the direction along the chord C (the straight line connecting the edge portion 51f and the edge portion 51e) (the chord direction D, the left-right direction in FIG. 4B). It is formed in a shape in which t (length in a direction orthogonal to the chord C) changes.

The maximum blade thickness position P0 at which the blade thickness t becomes the maximum blade thickness _tmax is located closer to the reservoir 27 than the center position of the blade chord length L (the straight line length from the edge portion 51f to the edge portion 51e). is doing. In other words, the pressurizing chamber side length Lc from the maximum blade thickness position P0 to the edge portion 51e on the pressurizing chamber 31 side is the reservoir side length Lm from the maximum blade thickness position P0 to the edge portion 51f on the reservoir 27 side. Longer than. The reservoir side angle θm formed by the blade surface and the chord C on the reservoir 27 side is larger than the pressure chamber side angle θc formed by the blade surface and the chord C on the pressurization chamber 31 side. .

  FIG. 5A and FIG. 5B are schematic diagrams for explaining the operation of the wing-like portion 51. FIG. 5A shows the state of ink flow during ink supply, and FIG. 5B shows the state of ink flow during ink ejection.

  As indicated by an arrow y11 in FIG. 5A, when ink is supplied, the ink flows from the reservoir 27 side to the pressurizing chamber 31 side due to the volume of the pressurizing chamber 31 increasing. On the other hand, as indicated by an arrow y13 in FIG. 5B, when ink is ejected, the volume of the pressurizing chamber 31 is reduced, so that the ink flows backward from the pressurizing chamber 31 side to the reservoir 27 side.

  Here, in the supply flow path 49, since the several wing | blade-shaped part 51 is arranged in the direction which cross | intersects a flow direction, it shows by the continuous line L1 (FIG. 5 (a)) and L3 (FIG.5 (b)). Thus, a flow path is formed between the wing-like parts 51. Then, the downstream side of the maximum blade thickness position P0 has a wider width (the cross-sectional area becomes larger) on the downstream side of the maximum blade thickness position P0. 55M (FIG. 5B) is included.

  In the widened flow path, the loss head (loss energy per unit mass of fluid) is larger than the flow path with a constant width or the narrow flow path. This is due to the generation of vortices and separation of the boundary layer. Further, in general, the loss head in the expanded flow path is an angle θ that spreads with respect to the flow path when the width is assumed to be constant (see FIG. 6A). Equally, the larger the reservoir side angle θm in the widening flow path 55M), the larger it becomes. On the other hand, reservoir side angle θm> pressure chamber side angle θc.

  Therefore, the loss head of the flow from the reservoir 27 side to the pressurizing chamber 31 side during ink supply is smaller than the loss head from the pressurization chamber 31 side to the reservoir 27 side during ink ejection. As a result, it is possible to suppress the back flow from the pressurizing chamber 31 side to the reservoir 27 side while promptly supplying ink from the reservoir 27 side to the pressurizing chamber 31 side. By suppressing the backflow, for example, the ink vibration flow on the descender 29 side is strengthened to suitably eject ink droplets, or the pressure propagates from the pressurizing chamber 31 to another pressurizing chamber 31 via the reservoir 27. (Fluid crosstalk) can be suppressed, and variations in discharge speed can be suppressed.

  5 (a) and 5 (b), the description has been made by paying attention to the flow path between the wing-like parts 51. However, the flow path between the wing-like part 51 and the inner peripheral surface of the supply flow path 49 is also described. The spreading channel is formed, and the same operation and effect as the channel between the wing-like parts 51 are exhibited. In other words, even if only one wing-like portion 51 is provided, the above-described functions and effects can be achieved.

  Further, the wing-like portion 51 has a rectifying effect for rectifying the ink flow. On the other hand, as can be understood from FIGS. 2 and 3, in the supply flow path 49, the direction in which the flow of the reservoir 27 extends and the penetration direction of the first supply hole 33a are perpendicular to each other, for example. There is. Therefore, the wing-like portion 51 is arranged at an appropriate position and orientation, such as being arranged obliquely with respect to two orthogonal flow paths in such a portion, so that the ink flow in the reservoir 27 is not excessive. And can contribute to prompt ink supply.

  The wing-like portion 51 can be a barrier that suppresses the propagation of pressure. On the other hand, in the reservoir 27, the pressure propagates between the plurality of first supply holes 33a. Accordingly, the wing-like portion 51 is disposed in the reservoir 27 with the blade surface facing the pressure propagation path between the plurality of first supply holes 33a, thereby suppressing pressure propagation and fluid crosstalk. Play.

  As described above, the wing-like portion 51 can contribute to the adjustment of the ink flow or the pressure propagation, and thus can contribute to the optimization of the ink supply. The wing-like portion 51 has various merits such as easy passage area as compared with a case where the flow path shape is changed to optimize ink supply.

  FIGS. 6A and 6B are diagrams for explaining a preferable range of the pressurizing chamber side angle θc and the reservoir side angle θm from the viewpoint of the effect of the above-described spreading flow path. These drawings are created based on "Machine Design Handbook" (Maruzen Co., 1974).

  FIG. 6A is a schematic diagram showing an experimental model. In the model, the fluid flows at a flow velocity V from the first flow path having the cross-sectional area A1 to the second flow path having the cross-sectional area A2, and between the first flow path and the second flow path at the downstream side at an angle θ. A spreading flow path is formed so as to expand.

In the experiment using this model, the following empirical formula is obtained.
h = ξ (θ) × (1- (A1 / A2)) ² × V ² / 2g
Here, h is a loss head, ξ (θ) is a loss coefficient, and g is a gravitational acceleration.
Therefore, the loss head h increases as the loss coefficient ξ (θ), which is a function of the angle θ, increases.

  FIG. 6B is a diagram showing the relationship between the angle θ and the loss coefficient ξ (θ). The horizontal axis indicates the angle θ (θm, θc), and the vertical axis indicates the loss coefficient ξ (θ).

In order to suppress the backflow from the pressurizing chamber 31 to the reservoir 27, in other words, to increase the loss of ink flow from the pressurizing chamber 31 to the reservoir 27, the reservoir side angle θm is increased (Lm is reduced). Small). On the other hand, according to FIG. 6B, the loss coefficient ξ (θ) is 1 or less when θm is less than 15 °, θm is 15 ° to 17.5 °, and θm is 90 ° (Lm = 0). The value 1 is almost equivalent to the time (also included in the present invention in this case), and monotonously increases until θm reaches 23 °, and reaches the maximum value 1.2. Note that tan (θm) = (t _max / 2) / Lm, and when θm = 15 °, Lc = 1.9 t _max .

Therefore, the reservoir side length Lm is preferably less than 1.9 t _max (θm> 15 °). In this case, a larger loss than when Lm = 0 can be obtained. If the lower limit of Lm is also taken into consideration, the reservoir-side length Lm is preferably in the range of 0 or more and less than 1.9 _tmax (15 ° <θm ≦ 90 °). More preferably, the pressurizing chamber side length Lc is in a range close to 1.18t _max (θm = 23 °) where the loss coefficient ξ (θ) is substantially the maximum value (for example, more than 1.12t _max 1). It is preferably less than 24 t _max (22 ° <θm <24 °).

In order to quickly supply ink, in other words, in order to reduce the loss of ink flow from the reservoir 27 to the pressurizing chamber 31, it is only necessary to decrease θc (Lc is increased). On the other hand, according to FIG. 6B, θc takes a minimum value of 5 to 6 °, and ξ (θ) does not decrease even if θc is further reduced. This is because θc becomes smaller, the surface area of the wing-like portion 51 is increased, and the friction loss is increased. Note that tan (θc) = (t _max / 2) / Lc, and when θc = 5 °, generally Lc = 5.7 t _max .

Therefore, the pressurizing chamber side length Lc is preferably less than 5.7 _tmax (θc> 5 °). In this case, it is not necessary to unnecessarily increase the chord length L. Incidentally, the pressurizing chamber side length Lc, since longer than the reservoir-side length Lm, if considered in conjunction with the preferred range of reservoir-side length Lm described above, 1.9 t _max ultra 5.7t less than _max ( The range is preferably 5 ° <θc <15 °. Further, more preferably, the pressurizing chamber side length Lc in the range (e.g., less than 4.1T _max ultra _{5.7t max (5 ° <θc <} 7 °)) close to 5.7T _max and is the fact Is preferred.

(Specific arrangement example of wing-shaped part)
Hereinafter, a specific arrangement example of the wing-like portion 51 will be described. In the following description, an alphabet may be appropriately added to the reference numeral of the substrate 35 to refer to the substrate 35A or the like.

  FIG. 7A and FIG. 7B are perspective views showing a specific arrangement example of the wing-like portion 51 in the pressurizing chamber 31.

  In FIG. 7A, the wing-like portion 51 is provided with the pressure application direction (z direction, thickness direction of the substrate 35) in the pressurizing chamber 31 as the wing width direction (direction perpendicular to the chord and wing thickness directions). It has been. Such a wing-like part 51 is formed, for example, by performing half etching for forming the pressurizing chamber 31 while leaving the wing-like part 51 on one surface of the substrate 35A. Note that half etching is performed on the other surface of the substrate 35A to form the second supply hole 33c leading to the pressurizing chamber 31 and the descender 29 (not shown in FIG. 7A).

  In FIG. 7B, the wing-like portion 51 is provided with the direction (plane direction of the substrate 35, the x direction) orthogonal to the pressure application direction in the pressurizing chamber 31 as the blade width direction. In such a wing-like part 51, for example, the pressurization chamber 31 is constituted by a plurality of substrates 35C to 35E, and in some of the substrates 35D, through-holes constituting the pressurization chamber 31 are left leaving the wing-like part 51. It is formed by forming. Further, the blade surface is formed by performing half-etching so that a tapered surface is formed on both surfaces of the substrate 35D.

  FIG. 8A and FIG. 8B are perspective views showing a specific arrangement example of the wing-like portion 51 in the reservoir 27.

  In FIG. 8A, the wing-like portion 51 is provided with the direction (plane direction of the substrate 35, y direction) intersecting the flow direction of the reservoir 27 as the wing width direction. In such a wing-like part 51, for example, the reservoir 27 is constituted by a plurality of substrates 35G and 35H, and a through-hole constituting the reservoir 27 is formed in a part of the substrates 35G, leaving the wing-like part 51. It is formed. Further, the blade surface is formed by performing half etching so that a tapered surface is formed on both surfaces of the substrate 35G.

  In FIG. 8B, the wing-like portion 51 is provided with the direction along the flow direction of the reservoir 27 (plane direction of the substrate 35, x direction) as the wing width direction. Note that both ends in the blade width direction are connected to the inner peripheral surface of the reservoir 27. Such a wing-like part 51 is formed by the same method as the wing-like part 51 of FIG.

  Note that the wing-like portion 51 is preferably provided in the reservoir 27. Since the reservoir 27 has a simpler ink flow than the pressurizing chamber 31 to which pressure is applied or the planar shape is not rectangular, the desired fluid phenomenon is obtained by the wing-like portion 51. Because it is easy. In addition, the reservoir 27 is wider than the communication path 33 and the wing-like portion 51 is easily provided.

  Further, when the wing-like portion 51 is provided in the reservoir 27, the pressure propagation between the first supply holes 33a in the reservoir 27 is suppressed. For example, in FIG. 8A, pressure propagation in the flow direction (x direction) of the reservoir 27 is suppressed, and in FIG. 8B, pressure propagation in the direction (y direction) intersecting the flow direction of the reservoir 27. Is suppressed.

  In FIGS. 8A and 8B, the wing-like portion 51 is arranged such that the chord is parallel to the opening direction (z direction) at the position where the first supply hole 33a in the reservoir 27 is opened. Although arranged, the chord may be arranged so as to be inclined in the opening direction of the first supply hole 33a.

  FIG. 9A and FIG. 9B are schematic views similar to FIG. 5A and FIG. 5B showing an arrangement example of the wing-like portion 51.

  In this example, a plurality (two in FIG. 9) of blade units 53 are arranged in the flow direction. Among the wing units 53, the plurality of wing-like parts 51 are different from each other in the position of the wing chord in the blade thickness direction (direction intersecting the flow direction, vertical direction on the paper surface). Preferably, between the wing units 53, the plurality of wing portions 51 do not overlap each other when viewed in the flow direction. More preferably, the wing portion 51 of one wing unit 53 is positioned between the wing portions 51 of the other wing unit 53.

  When a plurality of wing units 53 are arranged in this way, the above-described effect of the spreading channel and the rectifying effect can be increased. Further, the downstream wing-like portion 51 is prevented from being included in the negative pressure region of the upstream wing-like portion 51, and the effect of the flow path and the rectification effect can be increased efficiently. Even when three or more wing units 53 are arranged, the rectifying effect can be similarly increased if the wing units 53 adjacent to each other in the flow direction have different positions in the wing thickness direction of the wing-like portions 51. . In this case, in the blade units 53 that are not adjacent to each other in the flow direction, the positions of the plurality of blade portions 51 in the blade thickness direction may be the same.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The method for applying pressure to the pressurizing chamber may be an appropriate method. That is, the ink jet head is not limited to a piezo head, and may be a thermal head that applies pressure to ink by heating the ink to generate bubbles. In addition, the piezo-type inkjet head is not limited to the flexure mode head, and may be, for example, a longitudinal mode head that contracts the piezoelectric body in the vibration direction of the diaphragm, or a shear mode that uses shear deformation of the piezoelectric body. It may be a head. The flexure mode head is not limited to a unimorph type head, and may be a bimorph type head having two piezoelectric bodies facing each other.

  The shape of the individual flow path including the discharge hole, the pressurizing chamber, and the supply hole, and the shape of the reservoir are not limited to those illustrated in the embodiment. For example, the discharge hole, the pressurizing chamber, and the supply hole may be partially or entirely integrated, and the boundary position is not necessarily clear. For example, in the thermal head, the discharge hole and the pressurizing chamber may be integrated. Further, for example, the reservoir does not necessarily overlap the pressurizing chamber in plan view, and may extend in the transport direction or a direction obliquely intersecting the transport direction, and the number of pressurization chambers with respect to the number of rows is four. : 1.

  As exemplified in the embodiment, the wing-shaped portion has an effect of a spreading channel, a rectification effect, an effect of suppressing pressure propagation, and the like. The wing-like portion may be provided for any of these purposes, and does not necessarily have these effects. For example, the wing-shaped portion may be constituted by a flat blade (blade having a constant blade thickness in the chord direction) for the purpose of only the rectifying effect, and may be disposed along the (supply) flow path. Further, for example, the wing-like portion is configured by a flat blade for the purpose of only suppressing pressure propagation between the supply holes (33a) in the reservoir, and is disposed so as to be orthogonal to the flow direction of the reservoir between the supply holes (33a). May be.

  It should be noted that when the wing-like portion is arranged along the flow direction or the like, the wing-like portion does not necessarily have to be parallel to the flow direction or the like. Even if the wing-like portion is arranged at a certain angle of attack (for example, 45 ° or less) with respect to the flow direction or the like, it can be said that the wing-like portion is arranged along the flow direction or the like.

  The shape of the wing-shaped portion may be changed as appropriate. For example, in the embodiment, an airfoil (symmetric wing) in which a center line (a line connecting a point at an equal distance from one blade surface and the other blade surface from a leading edge to a trailing edge) and a chord coincide with each other is used. Although illustrated, these do not have to match. In other words, the camber (difference between the center line and the chord line) may be set to an appropriate size so that the center line is curved. In the embodiment, the wing-like portion in which the change rate of the blade thickness with respect to the chord direction is exemplified, but the change rate may be changed. Further, the blade surface is not limited to a flat surface, and may be configured by a curved surface. The maximum blade thickness position may be the center in the chord direction. In the embodiment, the shape (blade plane shape) when the blade surface is viewed in plan is exemplified as a rectangle (the chord length is constant in the blade width direction), but the blade plane shape is not limited to this. For example, it may be a triangle in which the chord length is shortened toward the wing tip. The corner of the wing may be chamfered by a curved surface (R may be given).

  Various effects of the above-described various shape changes can be considered. For example, by applying R to the corner of the blade (for example, at least one of the edge and the corner of the maximum blade thickness position), rapid change in flow can be suppressed and ink can be supplied quickly. Can do. Further, for example, by appropriately setting the change rate of the blade thickness with respect to the camber and / or chord direction, the ink can be rectified by the curved wing surface, and gradual rectification according to the flow path shape can be performed. .

  DESCRIPTION OF SYMBOLS 5 ... Inkjet head, 21 ... Base | substrate, 27 ... Reservoir, 29 ... Decender, 29a ... Discharge hole, 31 ... Pressurization chamber, 49 ... Supply flow path, 51 ... Wing-like part

Claims (8)

A base on which a flow path including a pressurizing chamber communicating with the discharge hole and a reservoir communicating with the pressurizing chamber is formed;
One or more wings disposed in the flow path;
An inkjet head having The wing-shaped portion is arranged such that the chord is along the flow direction, and the length Lc from the maximum blade thickness position where the blade thickness becomes the maximum blade thickness t _max in the chord direction to the edge on the pressurizing chamber side. The inkjet head according to claim 1, wherein the relationship between the maximum blade thickness position and the length Lm from the reservoir side edge to Lm is Lm <Lc. The inkjet head according to claim 2, wherein Lc <5.7 × t _max . The inkjet head according to claim 2, wherein Lm <1.9 × t _max . The inkjet head according to any one of claims 2 to 4, wherein the plurality of wing-like portions are arranged to be spaced apart from each other in the blade thickness direction. A plurality of wing units in which a plurality of the wing-like parts are arranged apart from each other in the wing thickness direction are arranged at different positions in the flow direction,
The position of the wing | blade part in one said wing | blade unit differs in the position of the wing | blade part in the said other wing | blade unit adjacent to a flow direction in each wing | blade unit, and a wing | blade thickness direction. Inkjet head. A plurality of supply holes leading to the plurality of pressurizing chambers are opened on the inner peripheral surface of the reservoir,
The inkjet head according to any one of claims 1 to 6, wherein the plurality of wing-like portions are arranged along a chord in an opening direction at a position where the plurality of supply holes in the reservoir are opened. . An inkjet head;
A control unit for controlling the inkjet head;
Have
The inkjet head is
A base on which a flow path including a pressurizing chamber communicating with the discharge hole and a reservoir communicating with the pressurizing chamber is formed;
One or more wings disposed in the flow path;
A recording apparatus.

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