JP5464364B2 - Liquid ejecting head, liquid ejecting head unit, and liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting head unit, and a liquid ejecting apparatus that eject liquid from nozzle openings, and more particularly, to an ink jet recording head, an ink jet recording head unit, and an ink jet recording apparatus that eject ink as liquid.

  A typical example of a liquid ejecting head that ejects droplets is an ink jet recording head that ejects ink droplets. As the ink jet recording head, for example, a nozzle plate having a nozzle opening, a channel forming substrate in which a liquid channel including a plurality of pressure generation chambers communicating with the nozzle opening is formed, and the channel forming substrate And a pressure generating means formed on one surface side.

  The liquid ejected from such a recording head has a viscosity suitable for ejection depending on the type of the liquid. Since the viscosity of the liquid has a correlation with the temperature, there is a characteristic that the lower the temperature, the higher the viscosity, and the higher the temperature, the lower the viscosity. For this reason, when a recording head designed to suit the viscosity of a liquid that is normally used is placed in a low-temperature (high-temperature) environment or when a high-viscosity (low-) liquid is discharged, the liquid is heated ( Cooling). Specifically, a heating means is provided in a case provided with a flow path such as an introduction path, and the ink viscosity is lowered by heating the ink by the heating means so as to obtain good ink ejection characteristics. (For example, refer to Patent Document 1).

JP 2010-023257 A

  However, since the heating means has a flat shape such as a film and is arranged in a plane on the side surface or inside of the case, the ink in the flow path provided in the case is warmed to a desired temperature in a short time. Insufficient ink that is not sufficiently warmed causes problems such as the inability to obtain the desired ejection characteristics, and the waiting time is prolonged because printing cannot be started before the ink is warmed to the desired temperature. Problems occur.

  Such a problem is not limited to an ink jet recording head that ejects ink, but also exists in a liquid ejecting head that ejects liquid other than ink.

  In view of such circumstances, the present invention provides a liquid ejecting head, a liquid ejecting head unit, and a liquid ejecting head that can suppress a decrease in ejection characteristics and a prolonged standby time by heating the liquid to a desired temperature in a short time. An object is to provide an apparatus.

An aspect of the present invention that solves the above-described problems includes a head body including a pressure generation chamber that communicates with a nozzle opening that ejects liquid, and pressure generation means that causes a pressure change in the pressure generation chamber, and the head body. And a case provided with an introduction path for supplying a liquid to the pressure generating chamber, and a protruding protrusion provided on the side surface of the fixing surface fixed to the head body of the case is spaced apart. And a plurality of the introduction paths are provided so as to open to the fixed surface of the convex portion and a surface on the opposite side of the fixed surface. The liquid ejecting head includes a film-like heating unit arranged along the unevenness formed by the portion.
In such an embodiment, by providing the case with a convex portion, the surface area of the case heated by the heating means can be increased, and the entire case can be efficiently heated. In addition, by providing a convex portion on the case and providing an introduction path on the convex portion, the area of the introduction path facing the heating means disposed on the outer periphery of the convex portion can be increased, and the heating means and the introduction path Can be shortened. Therefore, the liquid passing through the introduction path can be efficiently heated by the heating means, and the power of the heating means can be reduced.

  Here, it is preferable that the introduction path has an opening shape of a long hole, and a long axis of the long hole of the introduction path is arranged along a protruding direction of the protruding portion. According to this, the area which opposes the heating means of the introduction path can be further expanded, and the liquid passing through the introduction path can be efficiently heated.

  The plurality of introduction paths are preferably provided so as to have an equivalent opening area. According to this, since the flow resistance of the liquid passing through the introduction path can be made uniform and the supply characteristics can be made uniform, the liquid discharge characteristics can be made uniform.

  In addition, a plurality of the introduction paths are provided so that different types of liquid pass, and among the plurality of introduction paths through which different types of liquid pass, the introduction path through which the liquid serving as a reference for specific heat passes is provided. In addition, the area opposite to the heating means of the introduction path through which the liquid having a higher specific heat passes than the liquid to be used as the reference for the specific heat is widened, and the reference for the viscosity with respect to the introduction path through which the liquid for the reference of the viscosity passes It is preferable to widen the area facing the heating means of the introduction path through which the liquid having higher viscosity than the liquid to be passed passes. According to this, according to the specific heat and viscosity of the liquid that passes through the introduction path, it is possible to efficiently heat the liquid that is difficult to warm and to uniformize the viscosity of the discharged liquid. Print quality can be improved.

  Moreover, it is preferable that the said introduction path is provided so that the area which opposes the said heating means may become large toward the both ends part side of a juxtaposition direction. According to this, since the liquid that passes through the introduction path provided in the region that is difficult to be heated by the heat distribution of the heating means can be heated in the same manner as the liquid that passes through the introduction path in the region that is easily heated, the temperature is reduced. The liquid can be supplied with a uniform viscosity with a uniform viscosity.

According to another aspect of the invention, there is provided a liquid ejecting head unit including a plurality of liquid ejecting heads according to the above aspects.
In this aspect, it is possible to discharge the liquid with a uniform viscosity to make the discharge characteristics uniform and to discharge the liquid with the desired discharge characteristics. Therefore, it is possible to realize a liquid jet head unit with improved print quality.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head unit or the liquid ejecting head according to the above aspect.
In this aspect, a liquid ejecting apparatus with improved print quality can be realized.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a top view of the recording head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. FIG. 2 is a cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 2 is a cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 6 is a top view of a recording head according to Embodiment 2 of the invention. FIG. 6 is a top view illustrating another example of a recording head according to Embodiment 2 of the invention. FIG. 9 is a top view illustrating another example of a recording head according to Embodiment 3 of the invention. FIG. 6 is a cross-sectional view of a main part of a recording head according to Embodiment 3 of the invention. 1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention.

(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head that is an example of a liquid jet head according to Embodiment 1 of the present invention, FIG. 2 is a top view of the ink jet recording head, and FIG. FIG. 4 is a cross-sectional view taken along the line AA ′ and a cross-sectional view taken along the line BB ′ of FIG.

  As shown in FIG. 1, an ink jet recording head 1 (hereinafter also referred to as a recording head 1) of this embodiment includes a pair (two) of actuator units 2 and a housing 3 that can house the actuator unit 2 therein. And a flow path unit 5 joined to the tip surface (fixed surface) of the case 4.

  As shown in FIG. 3, the actuator unit 2 of the present embodiment includes a piezoelectric element forming member 13 in which a plurality of piezoelectric elements 11 that are actuators of the present embodiment are arranged in parallel in the width direction, and a piezoelectric element forming member 13. The base plate (other end portion) side is fixed as a fixed end so that the distal end portion (one end portion) side is a free end.

  The piezoelectric element forming member 13 includes a piezoelectric material layer 15 and internal electrodes constituting two poles of the piezoelectric element 11, that is, individual internal electrodes 16 constituting individual electrodes electrically independent of the adjacent piezoelectric elements 11, It is formed by alternately stacking common internal electrodes 17 constituting common electrodes that are electrically common to adjacent piezoelectric elements 11.

  The piezoelectric element forming member 13 is formed with a plurality of slits 18 by, for example, a wire saw or the like, and the ends of the slits are cut into comb teeth to form a row of piezoelectric elements 11. A positioning portion 19 having a width wider than each piezoelectric element 11 is provided on both outer sides of the row of piezoelectric elements 11. The positioning portion 19 is a non-driving vibrator that is formed of the piezoelectric element forming member 13 and is not substantially driven, like the piezoelectric element 11, and is positioned when the actuator unit 2 is incorporated into the recording head 1. The portion 19 is brought into contact with the side surface of the accommodating portion 3 provided in the case 4 to position the actuator unit 2 with high accuracy.

  Here, the region joined to the fixed plate 14 of the piezoelectric element 11 is an inactive region that does not contribute to vibration, and when a voltage is applied between the individual internal electrode 16 and the common internal electrode 17 constituting the piezoelectric element 11. Only the region on the tip side that is not joined to the fixed plate 14 vibrates. And the front end surface of the piezoelectric element 11 is fixed to an island portion 49 of a diaphragm 46 described later via an adhesive or the like.

  Further, each piezoelectric element 11 of the actuator unit 2 is connected to a circuit board 30 such as a COF on which a drive circuit 29 such as a drive IC for driving the piezoelectric element 11 is mounted.

  The flow path unit 5 includes a flow path forming substrate 40, a vibration plate 46 and a nozzle plate 48.

  The flow path forming substrate 40 is made of a silicon single crystal substrate, and a pressure generating chamber 42 defined by a plurality of partition walls is arranged in parallel in the width direction (short direction) on the surface layer portion on one surface side. Two rows are provided.

  As shown in FIG. 3, a manifold 44 that is a liquid reservoir for supplying ink, which is an example of liquid, to each pressure generation chamber 42 is provided on one end side in the longitudinal direction of each pressure generation chamber 42. Are communicated via an ink supply path 45 as an example. In the present embodiment, manifolds 44 communicating with the respective rows of the pressure generation chambers 42 are provided on both outer sides of the two rows of the pressure generation chambers 42. In addition, the opening surface side of the pressure generating chamber 42 of the flow path forming substrate 40 is sealed with a vibration plate 46, and a nozzle plate 48, which is an example of a nozzle forming member having a nozzle opening 47 formed on the other surface side, is bonded. It is bonded via an agent or a heat welding film. The nozzle opening 47 of the nozzle plate 48 and the pressure generating chamber 42 communicate with each other through a nozzle opening communication hole 43 provided through the flow path forming substrate 40.

  The diaphragm 46 is formed of a composite plate of, for example, an elastic film 46a made of an elastic member such as a resin film and a support plate 46b made of, for example, a metal material that supports the elastic film 46a. The side 46 a is joined to the flow path forming substrate 40. For example, in the present embodiment, the elastic film 46a as the first member is made of a PPS (polyphenylene sulfide) film having a thickness of about several μm, and the support plate 46b as the second member has a thickness of several tens. It consists of a stainless steel plate (SUS) of about μm.

  In addition, in the region of the diaphragm 46 that faces each pressure generating chamber 42, an island portion 49 is provided in which the tip of the piezoelectric element 11 contacts. That is, a thin portion 50 having a thickness smaller than that of other regions is formed in a region of the diaphragm 46 that faces the peripheral portion of each pressure generating chamber 42, and island portions 49 are provided inside the thin portion 50. Yes. In such an island portion 49, the tip end portion of the piezoelectric element 11 of the actuator unit 2 described above is fixed via an adhesive or the like, for example.

  Further, in the region facing the manifold 44 of the vibration plate 46, similarly to the thin portion 50, a compliance portion 54 that is substantially composed only of the elastic film 46 a is provided by removing the support plate 46 b by etching. . The compliance portion 54 absorbs the pressure change by the deformation of the elastic film 46a of the compliance portion 54 when a pressure change occurs in the manifold 44, and always keeps the pressure in the manifold 44 constant. Fulfill.

  In the present embodiment, the diaphragm 46 is constituted by the elastic film 46a and the support plate 46b, and the peripheral part of the island part 49 and the compliance part 54 are constituted only by the elastic film 46a. For example, the island portion 49 and the compliance portion 54 are formed by using a single plate-like member as the diaphragm and providing the concave thin-walled portion 50 or the like from which part of the plate-like member has been removed in the thickness direction. You may make it do.

  Thus, the flow path unit 5 provided with the pressure generating chamber 42 communicating with the nozzle opening 47 for discharging ink and the actuator unit 2 which is a pressure generating means for causing a pressure change in the pressure generating chamber 42 are implemented in this embodiment. Form the head body.

  As shown in FIGS. 1 and 2, the case 4 is fixed on the vibration plate 46 of the flow path forming substrate 40, and is connected to a liquid storage means such as an ink tank or an ink cartridge (not shown). An introduction path 56 for supplying ink to 44 is provided penetrating in the thickness direction.

  The case 4 is provided with two accommodating portions 3 that penetrate in the thickness direction, and the actuator unit 2 is positioned and fixed to each accommodating portion 3.

  As shown in FIG. 1, the housing portion 3 of the case 4 includes a fixed plate holding portion 3 a that is wider than the width of the fixed plate 14 on the side where the fixed plate 14 is fixed, and a piezoelectric element forming member. 13 has a piezoelectric element holding portion 3b that is narrower than the fixed plate holding portion 3a and slightly wider than the piezoelectric element forming member 13. The width here refers to the direction in which the piezoelectric elements 11 (pressure generation chambers 42) are arranged side by side. Further, as shown in FIG. 3, the fixing plate holding portion 3a of the accommodating portion 3 is provided with a step portion 3c so that the diaphragm 46 side becomes narrow in the penetrating direction. The end surface from which 11 protrudes contacts and is fixed to the step portion 3c.

  In addition, the case 4 has a fixed surface that is fixed to the diaphragm 46 at one surface where the accommodating portion 3 opens, and is provided on a pair of side surfaces that intersect with the fixed surface so as to protrude from the side surfaces. A plurality of convex portions 60 are provided. In the present embodiment, the convex portions 60 are provided on the side surfaces on both sides of the manifold 44 of the flow path unit 5 in the juxtaposed direction. A plurality of such convex portions 60 are provided at predetermined intervals on each side surface. Thereby, the recessed part 61 dented rather than the convex part 60 is formed between the convex part 60 and the convex part 60, and the side surface of the case 4 is formed by arranging the convex parts 60 and the concave parts 61 alternately. The uneven surface 62 is formed by repeating the unevenness. In the present embodiment, three convex portions 60 are arranged on each side surface of the case 4 at regular intervals along the longitudinal direction of the manifold 44, that is, the parallel direction of the pressure generating chambers 42.

  Such convex portions 60 are provided with a uniform protrusion amount from the thickness direction of the case 4, that is, from the fixed surface of the case 4 to the surface opposite to the fixed surface. And the convex part 60 is formed so that it may become the outer periphery of the continuous curved surface where a corner | angular part is not defined by the outer periphery formed by the convex part 60 and the recessed part 61. FIG. Further, the convex portion 60 is provided so as to be inclined such that the outer peripheral surface continuous from the concave portion 61 becomes an obtuse angle with respect to the concave portion 61. Thereby, the film-like heating means 70 which will be described in detail later can be easily placed in close contact with the uneven surface 62 on the side surface of the case 4.

  Each projecting portion 60 of the case 4 is provided with an introduction path 56 that penetrates in the thickness direction. The introduction path 56 penetrating in the thickness direction means that the introduction path 56 opens to a fixed surface joined to the flow path unit 5 of the case 4 and a surface opposite to the fixed surface. The three introduction paths 56 provided on the side surface side of the case 4 communicate with one manifold 44. Incidentally, the three introduction paths 56 are arranged side by side in the juxtaposed direction of the pressure generating chambers 42. Therefore, as shown in FIG. 4, ink can be supplied from the three introduction paths 56 into the manifold 44 at a uniform pressure over the direction in which the pressure generating chambers 42 are arranged, and the ink to each pressure generating chamber 42 is supplied. The supply characteristics can be made uniform, and the discharge characteristics can be made uniform. Incidentally, for example, when only one introduction path 56 communicates with the manifold 44, ink is supplied to the pressure generation chamber 42 far from the introduction path 56 at a low pressure, and the pressure generation chamber 42 near the introduction path 56 is supplied to the pressure generation chamber 42. Ink is supplied at high pressure. In such a configuration, when the rows of the pressure generating chambers 42 become longer due to the increase in the number of rows of the nozzle openings 47 and the manifold 44 becomes longer, the variation in the ink ejection characteristics due to the variation in the supply characteristics becomes large. Further, since the ink passing through one introduction path 56 is heated by the heating means 70, the ink may be cooled before reaching the pressure generating chamber 42 far from the introduction path 56. In the present embodiment, since ink is supplied to the manifold 44 from the three introduction paths 56, variation in supply characteristics can be reduced, ink ejection characteristics can be made uniform, and ink in the introduction paths 56 can be removed. The ink temperature in the manifold 44 can be reduced by efficiently heating.

  The introduction path 56 being provided in the convex portion 60 includes that at least a part of the introduction path 56 is open to the end surface (the fixed surface and the opposite surface) of the convex portion 60. That is, in the introduction path 56, all the openings may be open at the end face of the convex part 60 as in the present embodiment, and at least a part of the introduction path 56 is a convex part than the lowest part of the concave part 61. It may be provided so as to exit on the 60 side.

  Further, a film-like heating means 70 is provided along the concavo-convex surface 62 on the concavo-convex surface 62 on the side surface where the convex portion 60 of the case 4 is provided. Such a heating means 70 is a bendable film, and is curved along the uneven surface 62. Thereby, the heating means 70 and the side surface (uneven surface 62) of the case 4 are in close contact with each other without a gap. The bendable film-like heating means 70 includes, for example, a planar heater in which a heating resistor is sandwiched between sheets of resin or the like.

  As described above, the convex portion 60 is provided on the case 4, and the heating means 70 is arranged in close contact with the concave and convex surface 62 formed by the convex portion 60 without any gap, thereby making the side surface of the case 4 flat. In comparison with this, the surface area of the case 4 heated by the heating means 70 can be increased, and the entire case 4 can be heated efficiently.

Further, by providing the case 4 with the convex portion 60 and providing the introduction passage 56 in the convex portion 60, the area of the introduction passage 56 facing the heating means 70 that is in close contact with the outer periphery of the convex portion 60 can be increased. In addition, the distance between the introduction unit 56 facing the heating unit 70 and the heating unit 70 can be shortened. Thereby, the area where the ink passing through the introduction path 56 is warmed by the heating means 70 can be increased, and the ink supplied to the manifold 44 can be efficiently heated. Specifically, as shown in FIG. 5B, when the side surface of the case 104 is a flat surface, the circumferential width W < _b > ₂ where the introduction path 56 faces the heating unit 70 is short. On the other hand, as shown in FIG. 5A, in the case 4 of the present embodiment, the introduction path 56 is provided in the convex portion 60, so that the introduction path 56 faces the heating means 70 in the circumferential direction. it is possible to increase the width W _1. Further, as shown in FIG. 5 (a), introduction path 56 of the present embodiment, while the heating means 70 and the shortest distance L ₁ over most of the region opposed to the heating means 70, FIG. As shown in FIG. 5B, when the side surface of the case 104 is a flat surface, the shortest distance is only a part in the region where the introduction path 56 is opposed to the heating means 70, and the other parts are distances. Gradually spread. For this reason, by providing the convex portion 60 provided with the introduction path 56 in the case 4 as in the present embodiment, the area facing the heating means 70 of the introduction path 56 is widened and the heating of the introduction path 56 is performed. The distance to the means 70 can be maintained at a short distance, and the ink passing through the introduction path 56 can be warmed with high efficiency.

  Further, in such a configuration of the present embodiment, since the ink supplied to the manifold 44 can be efficiently heated by the heating unit 70, the power of the heating unit 70 can be reduced.

  Further, in such a configuration of the present embodiment, the ink supplied to the manifold 44 can be heated to a desired temperature in a short time, and therefore the ink temperature can be easily finely adjusted. As a result, the ink can be kept at a stable and constant temperature, the viscosity depending on the temperature of the ink can be kept constant, the ink droplet ejection characteristics can be stabilized, and the printing quality can be stabilized.

  Further, the case 4 is provided with a compliance space 55 having a concave shape that opens in a region facing the compliance portion 54. The compliance portion 54 is deformably held by the compliance space 55.

  Such a case 4 is formed of a resin material. In addition, the case 4 can be manufactured at a low cost by molding and can be easily mass-produced.

  In such a recording head 1, when ejecting ink droplets, the volume of each pressure generating chamber 42 is changed by deformation of the piezoelectric element 11 and the diaphragm 46 so that ink droplets are ejected from the predetermined nozzle openings 47. It has become. Specifically, when ink heated from an ink cartridge (not shown) through an introduction path 56 provided in the case 4 is supplied to the manifold 44, the ink is supplied to each pressure generating chamber 42 through the ink supply path 45. Distributed. Actually, the piezoelectric element 11 is contracted by applying a voltage to the piezoelectric element 11. As a result, the diaphragm 46 is deformed together with the piezoelectric element 11 to expand the volume of the pressure generating chamber 42, and ink is drawn into the pressure generating chamber 42. Then, after the ink is filled up to the nozzle opening 47, the voltage applied to the electrodes 16 and 17 of the piezoelectric element 11 is released in accordance with a recording signal supplied via the circuit board 30. As a result, the piezoelectric element 11 is expanded to return to the original state, and the diaphragm 46 is also displaced to return to the original state. As a result, the volume of the pressure generation chamber 42 contracts, the pressure in the pressure generation chamber 42 increases, and ink droplets are ejected from the nozzle openings 47.

(Embodiment 2)
FIG. 6 is a top view showing a case according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 6, the concave portions 61 are formed by providing the three convex portions 60 on both side surfaces of the case 4 </ b> A, and the concave and convex surfaces 62 are formed by the convex portions 60 and the concave portions 61. The uneven surface 62 is provided with a heating means 70 that adheres along the uneven surface 62.

  Each convex part 60 of such a case 4A is provided with introduction paths 56a to 56f. The introduction paths 56a to 56f are provided with introduction paths 56a to 56c on one side surface and introduction paths 56d to 56f on the other side surface.

  In such a case 4A, since there are side surfaces on which the heating means 70 is not provided on both end sides of the heating means 70, the heat distribution is biased. Specifically, the temperature at which both end portions of the heating means 70 are heated is lower than that at the central portion side together with the heat radiation from the side surface where the heating means 70 is not provided. For this reason, in this embodiment, the introduction paths 56a, 56c, 56d, and 56f on both ends of the heating means 70 are formed so that the openings are elongated holes (elliptical), and the major axis of the opening that becomes the elongated hole is convex. It arrange | positions along the protrusion direction (direction which cross | intersects the parallel arrangement direction of the introduction paths 56a-56c) of the part 60. FIG. Incidentally, the introduction passages 56b and 56e in the central part are formed so that the opening is a single hole (perfect circle).

  Such introduction paths 56 a, 56 c, 56 d, and 56 f are wider in the circumferential direction than the introduction paths 56 b and 56 e provided in the center portion, so that the width opposite to the heating means 70 is wider. The opposing areas spread. Therefore, the ink that passes through the introduction paths 56a, 56c, 56d, and 56f is likely to warm to a desired temperature in a shorter time than the ink that passes through the introduction paths 56b and 56e. Thereby, the temperature of the ink supplied from the three introduction paths 56a to 56c and 56d to 56f to the manifold 44 (see FIG. 1) is made uniform, and the occurrence of a bias in the temperature of the ink in the manifold 44 is suppressed. Ink can be ejected with uniform ejection characteristics.

  The opening areas of the introduction paths 56a, 56c, 56d, and 56f that are long holes and the opening areas of the introduction paths 56b and 56e that are single holes are preferably the same opening area. Thereby, the flow resistance of the ink passing through the introduction paths 56a to 56f can be made uniform, and the ink supply characteristics can be made uniform.

  In the present embodiment, the introduction paths 56a, 56c, 56d, and 56f at both ends of the heating means 70 are formed so that the openings are elongated holes, but the present invention is not particularly limited thereto. Here, another example is shown in FIG.

  As shown in FIG. 7, the case 4B is provided with introduction paths 56a to 56f, and the introduction paths 56a, 56c, 56d, and 56f on both ends of the heating means 70 are respectively connected to the introduction path 56b on the center side. The opening area is larger than that of 56e. In this way, even by widening the opening areas of the introduction paths 56a, 56c, 56d, and 56f, the area facing the heating means 70 of the introduction paths 56a, 56c, 56d, and 56f is increased, and the ink that passes through the heating means is heated. 70 can make it easy to warm.

(Embodiment 3)
FIG. 8 is a top view of a case according to Embodiment 3 of the present invention, and FIG. 9 is a plan view of a flow path unit according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 9, the flow path unit 5A (flow path forming substrate 40A) of the present embodiment is provided with two rows of pressure generation chambers 42. Further, the first manifold 44a, the second manifold 44b, and the third manifold 44c, which are independently arranged along the direction in which the pressure generation chambers 42 are arranged, are provided in one row of the pressure generation chambers 42 so as to communicate with each other. The fourth manifold 44d, the fifth manifold 44e, and the sixth manifold 44f, which are independently arranged along the direction in which the pressure generation chambers 42 are arranged, communicate with the other row of the pressure generation chambers 42. Is provided.

  A first introduction path 56g, a second introduction path 56h, and a third introduction path 56i of the case are provided in communication with the first manifold 44a, the second manifold 44b, and the third manifold 44c, respectively. Further, a fourth introduction path 56j, a fifth introduction path 56k, and a sixth introduction path 56l of the case 4 are provided in communication with the fourth manifold 44d, the fifth manifold 44e, and the sixth manifold 44f, respectively.

  Then, at least two kinds of different inks pass through the introduction paths 56g to 56l.

  In the present embodiment, ink serving as a reference for specific heat passes through the first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k. In contrast, the second introduction path 56h and the sixth introduction path 56l pass ink having a higher specific heat than the reference ink that passes through the first introduction path 56g and the like. Here, in the present embodiment, the reference ink is an ink having the lowest specific heat among a plurality of types of ink. The specific heat is the amount of heat necessary to increase the temperature of 1 g of the substance by 1 ° C. Therefore, the ink having a higher specific heat than the reference ink is an ink that is harder to warm than the reference ink. It is.

  The areas opposite to the heating means 70 of the second introduction path 56h and the sixth introduction path 56l through which such high specific heat ink passes are defined as the first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, The fifth introduction path 56k is made wider than the area facing the heating means 70. Specifically, in the present embodiment, as shown in FIG. 8, the second introduction path 56h and the sixth introduction path 56l of the case 4C are formed so that the opening is a long hole (ellipse) to be a long hole. The long axis of the opening is arranged along the protruding direction of the convex portion 60 (the direction intersecting the parallel direction of the introduction paths 56g to 56i). The first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k, which are other introduction paths, are formed so that the opening is a single hole (perfect circle).

  The second introduction path 56h and the sixth introduction path 56l are heated in the circumferential direction as compared with the other first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k. Since the width opposite to the means 70 is increased, the area opposite to the heating means 70 is increased. Therefore, the first introduction path 56g, the third introduction path 56i, and the fourth introduction path 56j through which the ink having a relatively high specific heat passing through the second introduction path 56h and the sixth introduction path 56l passes the ink having a relatively low specific heat. The heating can be performed in the same time as the fifth introduction path 56k until the desired temperature is reached. As a result, the temperature of the ink supplied to the first manifold 44a to the sixth manifold 44f is made uniform, and the occurrence of bias in the viscosity of the ink is suppressed, so that the ink can be ejected with uniform ejection characteristics. Therefore, the print quality can be improved.

  The opening areas of the second introduction path 56h and the sixth introduction path 56l that are long holes, and the first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k that are single holes. The opening area is preferably the same opening area. As a result, the flow resistance of the ink passing through all of the first introduction path 56g to the sixth introduction path 56l can be made uniform, and the ink supply characteristics can be made uniform.

  Of course, heating means can be obtained by making the opening areas of the second introduction path 56h and the sixth introduction path 56l wider than the first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k. The area opposite to 70 may be increased. In this way, when the opening areas of the second introduction path 56h and the sixth introduction path 56l are increased, the second introduction path 56h and the sixth introduction path 56l may be formed so that the openings are elongated holes (elliptical). In addition, it may be formed so as to be a single hole (perfect circle), and the opening shape is not particularly limited.

  Furthermore, in the above-described example, the specific heat has been described. However, the present invention is not particularly limited thereto, and the shape of the introduction path may be changed according to the viscosity indicating the ink characteristics.

  Here, it demonstrates using FIG. 8 demonstrated by the specific heat. When different types of ink having different viscosities are used at different temperatures, in the present embodiment, the first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k have viscosity standards. The ink which becomes becomes to pass. In contrast, ink having a higher viscosity than the reference ink that passes through the first introduction path 56g and the like passes through the second introduction path 56h and the sixth introduction path 56l. Here, in the present embodiment, the ink serving as a reference for viscosity refers to an ink having the lowest viscosity at the same temperature among a plurality of types of ink. An ink having a higher viscosity than the reference ink cannot be made to have the same viscosity as the reference ink unless heated to a temperature higher than that of the reference ink.

  Therefore, similarly to the specific heat described above, the areas of the second introduction path 56h and the sixth introduction path 56l opposite to the heating means 70 through which the high-viscosity ink passes are defined as the first introduction path 56g, the third introduction path 56i, The fourth introduction path 56j and the fifth introduction path 56k are made wider than the area facing the heating means 70. Specifically, as in the case of the specific heat described above, as shown in FIG. 8, the second introduction path 56h and the sixth introduction path 56l are formed so that the openings are elongated holes (elliptical), The major axis of the opening is arranged along the protruding direction of the convex portion 60 (the direction intersecting the parallel direction of the introduction paths 56g to 56i). The first introduction path 56g, the third introduction path 56i, the fourth introduction path 56j, and the fifth introduction path 56k, which are other introduction paths, are formed so that the opening is a single hole (perfect circle).

  As a result, the second introduction path 56h and the sixth introduction path 56l are heated in the circumferential direction in comparison with the other first introduction path 56g, third introduction path 56i, fourth introduction path 56j, and fifth introduction path 56k. Since the width opposed to 70 becomes wide, the area opposed to the heating means 70 increases. Therefore, the first introduction path 56g, the third introduction path 56i, and the fourth introduction path 56j through which the ink having a relatively high viscosity passing through the second introduction path 56h and the sixth introduction path 56l passes the ink having a relatively low viscosity. It can be heated until the same viscosity is obtained in the same time as the fifth introduction path 56k. Thereby, it is possible to suppress the occurrence of bias in the viscosity of the ink supplied to the first manifold 44a to the sixth manifold 44f, and to discharge the ink with uniform discharge characteristics. Therefore, the print quality can be improved.

  In the above-described example, when the ink that is the reference for the specific heat with the lowest specific heat and the ink that is the reference for the lowest viscosity are the same ink, the first introduction path 56g to the sixth introduction path shown in FIG. Although the shape of the path 56l is used, the ink that is the reference for the specific heat having the lowest specific heat and the ink that is the reference for the lowest viscosity may be different inks, and each may pass through different introduction paths. In this case, what is necessary is just to increase / decrease the area facing the heating means 70 of an introduction path suitably from the relationship between specific heat and a viscosity.

  Of course, the configuration of changing the area facing the heating means 70 in the introduction path according to the specific heat and the viscosity of the present embodiment is combined with the above-described second embodiment, thereby further uniformizing the ink viscosity and ink ejection characteristics. It is possible to improve the printing quality by making the uniform.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above. For example, in the first embodiment described above, three introduction paths 56 are provided on each side of the case 4, for a total of six, but the number and arrangement of the introduction paths 56 are not particularly limited to this, and the introduction paths 56 are not limited thereto. Four or more may be provided on one side of the cases 4 and 4A, and the intervals between the introduction paths 56 may be non-uniform. The opening shape of the introduction path 56 is not particularly limited, and may be any shape such as a circular shape, a triangular shape, a rectangular shape, or a polygonal shape. For example, the opening shapes of all the introduction paths 56 may be the same long holes as the introduction paths 56a and the like of the second embodiment.

  Further, for example, in Embodiments 2 and 3 described above, the opening shape of the introduction path 56 is changed or the opening area is increased in order to increase the area of the introduction path 56 facing the heating means 70. For example, the length of the introduction path 56 (the length from the fixed surface to the surface opposite to the fixed surface) is changed by, for example, inclining, so as to face the heating unit 70. The area may be increased or decreased.

  Further, in Embodiments 2 and 3 described above, the area facing the heating means 70 of the introduction path 56 is changed in two stages, but the present invention is not limited to this, and the area relative to the heating means 70 of the introduction path 56 is relatively limited. You may make it change the area to face in three steps or more. In other words, the area of the introduction path 56 facing the heating means may be gradually increased toward both ends in the juxtaposed direction.

  Further, in each of the above-described embodiments, the piezoelectric material layers 15, the individual internal electrodes 16, and the common internal electrodes 17 are alternately stacked as a pressure generation unit that causes a pressure change in the flow path (pressure generation chamber 42). The longitudinal vibration type piezoelectric element 11 that expands and contracts in the direction is illustrated, but the pressure generating means is not particularly limited to this, and the piezoelectric material layers 15, the individual internal electrodes 16, and the common internal electrodes 17 are alternately stacked. Then, a lateral vibration type piezoelectric element in which one end portion in the stacking direction is brought into contact with the island portion may be used.

  Further, as the pressure generating means, for example, a thin film type piezoelectric element in which a lower electrode, a piezoelectric layer made of a piezoelectric material, and an upper electrode are formed by a film forming and lithography method may be used, or a green sheet is attached. A thick film type piezoelectric element formed by such a method can also be used. Also, as a pressure generating means, a heating element is arranged in the pressure generating chamber, and droplets are discharged from the nozzle opening by bubbles generated by the heat generated by the heating element, or static electricity is generated between the diaphragm and the electrode. In addition, it is possible to use a device in which a diaphragm is deformed by electrostatic force and droplets are ejected from a nozzle opening.

  In addition, the ink jet recording head 1 of each of the embodiments constitutes a part of an ink jet recording head unit including an ink flow path communicating with an ink cartridge and the like, and is mounted on the ink jet recording apparatus. FIG. 10 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus 200 shown in FIG. 10, an ink jet recording head unit 202 having a plurality of ink jet recording heads 1 (hereinafter also simply referred to as a head unit 202) is attached and detached with cartridges 202A and 202B constituting ink supply means. The carriage 203 on which the head unit 202 is mounted is provided on a carriage shaft 205 attached to the apparatus main body 204 so as to be movable in the axial direction. For example, the head unit 202 discharges a black ink composition and a color ink composition.

  Then, the driving force of the driving motor 206 is transmitted to the carriage 203 via a plurality of gears and a timing belt 207 (not shown), so that the carriage 203 on which the head unit 202 is mounted is moved along the carriage shaft 205. On the other hand, the apparatus main body 204 is provided with a platen 208 along the carriage shaft 205, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 208. It is designed to be transported.

  In the ink jet recording apparatus 200 described above, the head unit 202 having the plurality of recording heads 1 is mounted on the carriage 203 and moves in the main scanning direction. However, the present invention is not particularly limited thereto, and for example, recording The present invention can also be applied to a so-called line type recording apparatus in which the head 1 is fixed and printing is performed simply by moving the recording sheet S such as paper in the sub-scanning direction.

  In the above-described example, the head unit 202 having a plurality of recording heads 1 is mounted on the ink jet recording apparatus 200. However, one recording head 1 may be mounted on each head unit 202. In addition, one or a plurality of recording heads 1 may be directly mounted on the ink jet recording apparatus 200.

  In the above-described embodiment, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to a liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  DESCRIPTION OF SYMBOLS 1 Inkjet recording head (liquid ejecting head), 2 Actuator unit, 3 Accommodating part, 4, 4A, 4B, 4C case, 5, 5A channel unit, 11 Piezoelectric element (actuator), 13 Piezoelectric element formation member, 14 Fixing Plate, 16 Individual internal electrode, 17 Common internal electrode, 18 Slit, 19 Positioning part, 30 Circuit board, 40, 40A Flow path forming board, 42 Pressure generating chamber, 44, 44a-44f Manifold, 46 Vibration plate, 47 Nozzle opening , 48 nozzle plate, 49 island part, 56, 56a to 56l introduction path, 60 convex part, 61 concave part, 62 uneven surface, 200 ink jet recording apparatus (liquid ejecting apparatus), 202 ink jet recording head unit (liquid ejecting head unit) )

Claims (8)

A head body comprising: a pressure generating chamber communicating with a nozzle opening for ejecting liquid; and a pressure generating means for causing a pressure change in the pressure generating chamber;
A case provided with an introduction path for supplying a liquid to the pressure generating chamber of the head body,
A plurality of protrusions provided in a protruding manner are arranged at intervals on the side surface of the fixed surface fixed to the head body of the case,
The introduction path is provided so as to open to the fixed surface of the convex portion and a surface opposite to the fixed surface;
The liquid ejecting head according to claim 1, further comprising: a film-like heating unit disposed on the side surface of the case along the unevenness formed by the convex portion.   The liquid ejecting head according to claim 1, wherein the introduction path has an opening shape of a long hole, and a long axis of the long hole of the introduction path is disposed along a protruding direction of the protruding portion. .   The liquid ejecting head according to claim 1, wherein the plurality of introduction paths are provided so as to have an equivalent opening area. A plurality of the introduction passages are provided so that different kinds of liquids pass therethrough,
Of the plurality of introduction paths through which different types of liquids pass, the heating means of the introduction path through which a liquid having a higher specific heat passes than the introduction path through which the liquid serving as the reference for specific heat passes passes. And the opposite of the heating means of the introduction path through which the liquid having a higher viscosity than the liquid serving as the viscosity reference passes with respect to the introduction path through which the liquid serving as the viscosity reference passes. The liquid ejecting head according to claim 1, wherein the area is widened.   The said introduction path is provided so that the area which opposes the said heating means may become large toward the both-ends part side of a juxtaposition direction, It is any one of Claims 1-4 characterized by the above-mentioned. Liquid jet head.   A liquid ejecting head unit comprising a plurality of the liquid ejecting heads according to claim 1.   A liquid ejecting apparatus comprising the liquid ejecting head unit according to claim 6.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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