JP2009096041A - Ink jet head and ink jet head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet head capable of smooth circulation of ink in an ink jet head, a reduction in the size of an ink jet head chip, and reliable removal of air bubbles. <P>SOLUTION: A main body section 3 includes a first common ink groove 11 communicating with a plurality of ink grooves 6 on the one end side of the ink grooves 6, and a second common ink groove 21 communicating with the ink grooves 6 on the other end side of the ink grooves 6. In the area where a first plane S intersects a first common ink chamber 11a, the area where the first plane S1 intersects the center of a first channel opening 13a is larger than the area where the first plane S1 intersects the endmost ink groove 6 in the direction of Y axis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inkjet head (used in a printer or the like) and an inkjet head device.

  In recent years, in printers, non-impact printing apparatuses such as an ink jet system that can easily cope with colorization and multi-gradation are rapidly spreading instead of impact printing apparatuses. As an ink jet head as an ink ejecting apparatus used for this, a drop-on-demand type in which only ink droplets necessary for printing are ejected is attracting attention because of its excellent ejection efficiency and ease of cost reduction. Yes. The drop-on-demand type is mainly the Kayser method or the thermal jet method.

  However, the Kaiser method has a drawback that it is difficult to reduce the size and is not suitable for high density. Although the thermal jet method is suitable for increasing the density, the ink is heated with a heater to generate bubbles in the ink and ejected using the energy of the bubbles. However, the heat resistance of the ink is required, and it is difficult to extend the life of the heater, and the energy efficiency is poor, so that the power consumption increases.

  In order to solve such drawbacks of each method, an ink jet method using shear mode deformation of a piezoelectric material has been proposed. This method uses an electrode formed on both sides of an ink channel wall made of piezoelectric material (hereinafter referred to as “channel wall”) to generate an electric field in a direction perpendicular to the polarization direction of the piezoelectric material. The channel wall is deformed in the share mode, and ink droplets are ejected by utilizing the pressure wave fluctuation generated at that time, which is suitable for increasing the density of the nozzles, reducing the power consumption, and increasing the driving frequency.

  Recently, the use of ink jet heads utilizing this shear mode deformation for industrial purposes has become active. For example, wiring is drawn by discharging a conductive material as ink, a color filter is manufactured by discharging inks of R, G, and B colors, or thermosetting or ultraviolet (UV) curable ink. The application of producing a three-dimensional structure such as a microlens or a spacer by discharging the liquid is being promoted.

  Especially in industrial applications, in addition to the demand for high-definition ejection by increasing the density of nozzles, the demand for lower density of nozzles has begun to appear as the liquid crystal screen becomes larger. When comparing the use of an inkjet head for industrial use and the use of an inkjet head as a consumer product printer, the difference is the severity of required accuracy. Industrial applications are required to operate with much higher accuracy than consumer products. In industrial applications, it is required to land a specified amount of droplets at a specified address, and control of landing accuracy and droplet amount is strictly required. Therefore, the fact that ink channels that should be able to be ejected in a single inkjet head cannot be ejected due to any obstacles such as bubbles or dust is generated at a level that is not a problem for consumer use. Even if it is a rate, it becomes a serious problem when using an inkjet head for industrial use.

  In addition, with the development of such a wide variety of inkjet application fields, a variety of inks are used. For example, highly volatile ink containing an organic solvent, strongly acidic / strongly alkaline ink, ink containing pigments and resin components, ink containing fine particles such as beads, and ink combining these. It is done. In particular, in ink containing fine particles such as beads, fine particles are precipitated or floated due to a difference in specific gravity between the ink solvent and the contained fine particles, which may cause uneven distribution of the fine particle concentration in the ink. When the distribution is biased, the number of fine particles contained in the droplets at the time of ejection varies, resulting in product performance deterioration and defect occurrence. In order to avoid such a situation, it is necessary to prevent the precipitation of fine particles by circulating and stirring the ink in the ink tank and the ink jet head. More strictly speaking, in order to stably discharge the number of fine particles contained in the droplet at the time of discharge, it is important that the above-described ink circulation and stirring are performed even when the ink is close to the nozzle hole. It is. Further, in order to make the volume of ink ejected constant while circulating and stirring, it is necessary to keep the negative pressure applied to each nozzle hole constant.

  As a technique for circulating and stirring ink up to the vicinity of a nozzle hole, there is one described in International Publication WO95 / 31335 (Patent Document 1). In the inkjet head shown in FIGS. 2 and 3 of Patent Document 1, the pressure generating chamber is a space in which a nozzle plate having nozzle holes on the front side and a diaphragm on the rear side are arranged. Two common ink chambers are arranged on both sides of the pressure generation chamber so as to sandwich the pressure generation chamber, and these two common ink chambers communicate with the pressure generation chamber. This apparatus has a structure capable of supplying ink from one common ink chamber to the other common ink chamber via a pressure generating chamber. In this ink jet head, the pressure generation chamber itself with the nozzle holes serves as a path for the ink, so that the ink can be circulated to the immediate vicinity of the nozzle holes. FIG. 4 of Patent Document 1 shows the entire recording apparatus including the ink jet head. In this recording apparatus, ink is replenished from the ink cartridge to the sub tank via the ink jet head. It is also possible to return the ink to the ink cartridge via the ink jet head by utilizing the water head difference. In the recording apparatus of Patent Document 1, the ink is circulated in this way.

  In the inkjet head described in Japanese Patent Application Laid-Open No. 2006-142509 (Patent Document 2), two common ink chambers are provided as two grooves parallel to each other on the surface of the piezoelectric substrate. A large number of groove-shaped pressure generating chambers are provided so as to be sandwiched between these two common ink chambers and communicate with both of these two common ink chambers. Patent Document 2 proposes an ink jet head that utilizes shear mode deformation of a piezoelectric material in the wall portion of the groove-shaped pressure generating chamber.

  Japanese Unexamined Patent Application Publication No. 2004-1368 (Patent Document 3) describes an inkjet head having a structure in which a common groove for supplying / discharging ink is processed from the back surface of a substrate.

  One type of inkjet head is a stacked type. This is to assemble the structure of the ink jet head by overlapping each member while aligning them, and an example thereof is described in JP-A-6-183029 (Patent Document 4).

Also, Japanese Patent No. 3097718 (Patent Document 5) describes a method for circulating and stirring ink to the vicinity of the nozzle hole and eliminating air bubbles.
International Publication WO95 / 31335 JP 2006-142509 A JP 2004-1368 A JP-A-6-183029 Patent No. 3097718

  As described above, in the recording apparatus described in Patent Document 1, when ink is exchanged between the ink cartridge and the sub tank, the ink is transferred from one common ink chamber to the other common ink chamber in the course of the circulation. Since the ink is supplied through the pressure generation chamber, it is possible to circulate the ink to the vicinity of the nozzle hole. However, this ink jet head has a drawback that it is a multilayer ink jet head.

  As described in Patent Document 4, the multilayer ink jet head includes a vibrator unit in which a vibrator is attached to a base, a flow path component member, a diaphragm forming member, a pressure generation chamber, It is composed of five members: a spacer for forming a gap to be formed and a nozzle plate having nozzle holes. These members are assembled by aligning and overlapping each other. In order to achieve high landing accuracy and uniform ejection performance in an inkjet head, the relative positional accuracy of the nozzle hole and the drive unit is extremely important, and the center of the nozzle hole matches the center of the ink path in the drive unit. Must be placed. Therefore, these five members are required to be aligned with high accuracy. That is, in order to produce one ink jet head, it is necessary to repeat such highly accurate alignment four times, resulting in a decrease in yield. In addition, the ink jet head of Patent Document 4 uses a laminated piezoelectric element in order to ensure the amount of displacement, and the number of parts constituting the ink jet head itself is large. In such a case, it is not suitable for miniaturization and leads to an increase in cost.

  On the other hand, as an example of the non-stacked inkjet head, there is a share mode inkjet head described in Patent Document 2. This ink jet head is assembled by housing a piezoelectric substrate having a plurality of grooves in a manifold having an oval recess and covering a nozzle plate having a plurality of nozzle holes.

  The following grooves are formed in the piezoelectric substrate used in the ink jet head of Patent Document 2. First, as the first groove, there are a plurality of parallel grooves A that become pressure generation chambers by covering the nozzle plate. An electrode is formed on the inner wall of the groove A serving as the pressure generating chamber. When a voltage is applied from the outside, the groove serving as the pressure generating chamber is deformed in the shear mode, and ink is ejected from the nozzle.

  Next, as the second groove, there is a groove B that is electrically connected to the groove A serving as each pressure generating chamber described above. An electrode is also formed on the inner wall of the groove B. By electrically connecting the groove B and an external voltage applying mechanism, a voltage can be applied to the groove A serving as a pressure generating chamber via the groove B. it can. In order to electrically connect to an external voltage application mechanism and to suppress ink leakage, the depth of the groove B needs to be very shallow with respect to the groove A serving as a pressure generating chamber. Therefore, the groove B is connected to the groove A via the R-shaped portion. Originally, this R-shaped portion is a portion that is not necessary, but it is generated when the R of the blade is transferred when the dicing machine or the like is processed to connect grooves having different groove depths. Since the radius of the blade is very large with respect to each groove, the area occupied by the R-shaped portion in the piezoelectric substrate is very large, and the presence of the R-shaped portion leads to an increase in size of the piezoelectric substrate.

  Further, as the third groove, there is a groove C formed so as to be orthogonal to the groove A serving as a pressure generating chamber, and a portion surrounded by the groove C and the nozzle plate is a common ink chamber. Since the common ink chamber serves to supply ink to each pressure generation chamber, the common ink chamber needs to intersect with a plurality of pressure generation chambers. Further, since the common ink chamber needs to supply a sufficient amount of ink, the volume should be sufficiently large. In order to increase the volume of the common ink chamber, there is means for increasing the width of the groove C or increasing the depth. However, if the depth is deeper than the groove A serving as the pressure generating chamber, the grooves A and B Can not be made deeper than the groove A. Therefore, it is necessary to increase the width, but increasing the width of the groove C increases the size of the piezoelectric substrate.

  According to these results, the piezoelectric substrate necessary for the ink jet head is enlarged in the configuration of Patent Document 2, and the material cost increases because the piezoelectric substrate is expensive.

  On the other hand, the ink jet head described in Patent Document 3 has a structure in which a common groove (common ink chamber) for supplying / discharging ink is processed from the back surface of the substrate. In comparison, the depth of the common ink chamber can be increased. This leads to lowering the flow path resistance of the common ink chamber, and therefore has the advantage that the ink circulation in the ink jet head can be made smoother.

  However, since the inkjet head described in Patent Document 3 has a configuration in which only a part of the side wall of the groove formed in the substrate is formed by piezoelectric ceramics, there is a problem in ejection performance and reliability.

  In this configuration, the region that contributes to ink ejection among the side walls of the pressure generating chamber is formed by piezoelectric ceramics. In other regions, the side walls are formed by insulating ceramics or the like. Therefore, when the piezoelectric ceramic that is part of the side wall is deformed to eject ink, both ends of the piezoelectric ceramic on the side wall are bonded to insulating ceramics and the like, so that the deformation is hindered. The discharge efficiency is reduced. In addition, when piezoelectric ceramics are bonded to insulating ceramics or the like, variations in the thickness of the adhesive also affect variations in deformation of the piezoelectric ceramics. Therefore, it is expected that the discharge characteristics vary for each channel. Furthermore, when the groove is processed, a difference in level may occur due to different processing characteristics between the adhesive portion, the piezoelectric ceramic, and the insulating ceramic. Due to this step, conduction may not be obtained at the time of electrode formation, and there is a problem in reliability.

  As described above, in the ink jet head, the ink should be circulated to the vicinity of the nozzle hole in order to avoid the problem that the channel that should be able to be discharged cannot be discharged due to some trouble such as bubbles and dust. Patent Document 5 discloses a method for stirring and excluding bubbles. This patent document 5 is demonstrated using FIG. FIG. 14 shows a state where the nozzle plate 802 provided with the nozzle holes 808 is removed.

  In this configuration, in order to eliminate bubbles, the first reservoir 820 and the second reservoir 821 are communicated not only with the pressure generation chamber 822 but also with the communication path 827. At the time of filling and supplying, after the ink and bubbles pass through the first supply pipe 823, the first supply port 825, and the first reservoir 820, not only the pressure generation chamber 822 but also the communication path 827 pass in the same way, and the second supply port 826 passes through the second supply pipe 824. In this configuration, by having the communication path 827 that does not have the same flow resistance as that of each pressure generation chamber 822, the flow of ink becomes non-uniform regardless of where the communication path 827 is arranged, and the ink is made uniform. Can't circulate. In addition, bubbles with a width equal to the width of each reservoir are moved by being pressed against the ink by applying pressure to the bubbles when the bubbles block the reservoir. Since there is nothing to guide the flow, bubbles remain on the wall, corners, etc., and once they stop, the ink preferentially passes through places other than the bubbles due to the difference in flow path resistance, so the bubbles cannot be removed. ing.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet head and an ink jet head device that can smoothly circulate ink in the ink jet head, reduce the size of the ink jet head chip, and reliably eliminate bubbles. There is.

In order to solve the above problems, the inkjet head of the present invention is
It has a plurality of ink grooves extending in one direction (X-axis direction) and opening at both ends, and the plurality of ink grooves are parallel to each other in the other direction (Y-axis direction) perpendicular to the one direction. An array of piezoelectric substrates;
The piezoelectric substrate is attached, has a first common ink groove communicating with the plurality of ink grooves on one end side of the plurality of ink grooves, and communicates with the plurality of ink grooves on the other end side of the plurality of ink grooves. A main body having a second common ink groove;
The plurality of ink grooves, the first common ink groove and the second common ink groove are arranged so as to cover from above, and a plurality of individual ink chambers are defined together with the plurality of ink grooves, together with the first common ink groove A nozzle plate defining a first common ink chamber and defining a second common ink chamber together with the second common ink groove;
The main body has a first flow passage opening communicating with the first common ink chamber and a second flow passage opening communicating with the second common ink chamber, and the nozzle plate is located at a position corresponding to the ink groove. Has nozzle holes,
In the area where the first plane perpendicular to the other direction intersects the first common ink chamber, the area at the position where the first plane intersects the center of the first flow path port is the first plane is the other direction. It is characterized by being larger (continuously or stepwise) than the area at the position where it intersects the outermost ink groove.

  According to the inkjet head of the present invention, the main body has the first common ink groove communicating with the plurality of ink grooves on one end side of the plurality of ink grooves, and the other end side of the plurality of ink grooves. Since the second common ink groove communicates with the plurality of ink grooves, the first common ink groove and the second common ink groove can be adjusted by appropriately adjusting the width and depth of the first common ink groove and the second common ink groove. The flow resistance of the two common ink grooves can be made sufficiently smaller than the flow resistance of the individual ink chamber, and the ink flow through the individual ink chamber can be easily promoted in the ink jet head. In addition, the number of inkjet heads that can be obtained from a single wafer-like piezoelectric substrate (so-called “number of picks”) is not affected at all.

  Further, in the area where the first plane and the first common ink chamber intersect, the area at the position where the first plane intersects the center of the first flow path port is the first plane is the extreme end in the other direction. Since the area is larger than the area at the position where the ink groove intersects, the bubbles mixed into the first common ink chamber from the first flow path opening do not first pass through the ink groove having a high flow path resistance, and the end of the piezoelectric substrate. After it hits, it moves to the end portion in the other direction far from the first flow path port and tries to stay there, but when the bubble moves to the ink groove position on the end portion side, the shape of the bubble is changed. By pushing into the region of the end while changing, it is possible to allow bubbles to pass through the ink groove, and it is possible to prevent bubbles from remaining in the first common ink chamber.

  In other words, when bubbles are trapped, the unintended bubbles flow, resulting in unstable ejection parameters or non-ejection, but bubbles remain in the first common ink chamber. By preventing this, it is possible to provide an inkjet head with high ejection reliability that prevents unintended bubbles from flowing during ejection.

  Accordingly, it is possible to realize an ink jet head that can smoothly circulate ink in the ink jet head, can be downsized without complicating the ink jet head, and can reliably eliminate bubbles.

  Further, in the ink jet head according to an embodiment, in the area where the second plane perpendicular to the other direction intersects with the second common ink chamber, the area at the position where the second plane intersects the center of the second flow path port is as follows. The area of the second plane is larger than the area at the position where it intersects with the outermost ink groove in the other direction.

  According to the ink jet head of this embodiment, the area at the position where the second plane intersects the center of the second flow path opening is larger than the area at the position where the second plane intersects the outermost ink groove in the other direction. Therefore, the bubbles flowing into the second common ink chamber through the first common ink chamber and the ink groove move so as to be guided in the direction of the second flow path opening having a large cross-sectional area. Bubbles can be effectively discharged in the second common ink chamber, and bubbles can be prevented from remaining.

  In one embodiment, at least a part of the side surface of the first common ink groove facing the end of the ink groove is formed in a concave curved surface.

  According to the inkjet head of this embodiment, since at least a part of the side surface of the first common ink groove is formed in a concave curved surface, the side surface of the first common ink groove causes bubbles to be formed on the end side. Preventing bubbles from remaining on the side surfaces of the first common ink groove without being trapped by a plane or corner when guided so as to be pressed against the piezoelectric substrate as it moves to the ink groove position. Can do.

  In one embodiment, at least a part of the side surface of the second common ink groove facing the end of the ink groove is formed in a concave curved surface.

  According to the inkjet head of this embodiment, since at least a part of the side surface of the second common ink groove is formed in a concave curved surface, the side surface of the second common ink groove causes bubbles to be formed on the end side. Preventing bubbles from remaining on the side surfaces of the second common ink groove when being guided so as to be pressed against the piezoelectric substrate as it moves to the ink groove position without being trapped by a plane or corner. Can do.

  In one embodiment, at least a part of the bottom surface of the first common ink groove facing the nozzle plate is formed in a concave curved surface.

  According to the ink jet head of this embodiment, since at least a part of the bottom surface of the first common ink groove is formed in a concave curved surface, the nozzle hole is disposed downward (gravity direction) and ink is ejected downward. When the bubbles are subjected to buoyancy and are pressed against the bottom surface of the first common ink groove on the opposite side to the gravitational direction, the bubbles are not trapped by a plane or a step, and the bubbles are not trapped in the first common ink groove. It is possible to prevent remaining on the bottom surface.

  In one embodiment, at least a part of the bottom surface of the second common ink groove facing the nozzle plate is formed in a concave curved surface.

  According to the ink jet head of this embodiment, since at least a part of the bottom surface of the second common ink groove is formed as a concave curved surface, the nozzle holes are arranged downward (gravity direction) and ink is ejected downward. When the bubbles are subjected to buoyancy and are pressed against the bottom surface of the second common ink groove on the opposite side to the gravitational direction, the bubbles are not trapped by a plane or a step, and the bubbles are not trapped in the second common ink groove. It is possible to prevent remaining on the bottom surface.

  In one embodiment, at least a boundary surface between a side surface of the first common ink groove facing the end portion of the ink groove and a bottom surface of the first common ink groove facing the nozzle plate is provided. A part is formed in a concave curved surface.

  According to the ink jet head of this embodiment, at least a part of the boundary surface between the side surface of the first common ink groove and the bottom surface of the first common ink groove is formed in a concave curved surface. Bubbles can be discharged without causing bubbles to stay on the surface.

  In one embodiment, at least a boundary surface between a side surface of the second common ink groove facing the end of the ink groove and a bottom surface of the second common ink groove facing the nozzle plate is used. A part is formed in a concave curved surface.

  According to the inkjet head of this embodiment, since at least a part of the boundary surface between the side surface of the second common ink groove and the bottom surface of the second common ink groove is formed as a concave curved surface, Bubbles can be discharged without causing bubbles to stay on the surface.

  In the inkjet head according to an embodiment, the first plane is the first flow path port in the width of the first common ink groove on the plane parallel to the plane including the one direction and the other direction. Is wider (continuously or stepwise) than the width at the position where the first plane intersects the outermost ink groove in the other direction.

  According to the ink jet head of this embodiment, the first plane is the first flow path port in the width of the first common ink groove on the plane parallel to the plane including the one direction and the other direction. The width of the first common ink groove facing the end of the ink groove is larger than the width of the first plane where the first plane intersects the outermost ink groove in the other direction. The side surface can be formed narrower toward the end of the ink groove than the first channel port.

  For this reason, the side surface of the first common ink groove can guide the air bubble so as to be pressed against the piezoelectric substrate as it moves to the ink groove position on the end side, thereby ensuring the remaining of the air bubble in the first common ink chamber. Can be prevented.

  In the ink jet head according to an embodiment, the depth at the position where the first plane intersects the center of the first flow path port in the depth of the first common ink groove on the plane orthogonal to the one direction is as follows: It is larger (continuously or stepwise) than the depth at the position where the first plane intersects the outermost ink groove in the other direction.

  According to the inkjet head of this embodiment, in the depth of the first common ink groove on the plane orthogonal to the one direction, the depth at the position where the first plane intersects the center of the first flow path port is: Since the first plane is larger than the depth at the position where it intersects with the outermost ink groove in the other direction, the bottom surface of the first common ink groove facing the nozzle plate is located farthest from the first flow path port. It can be formed shallower on the ink groove side.

  For this reason, when the nozzle hole is disposed downward (gravity direction) and ink is ejected downward, the bottom surface of the first common ink groove causes the bubble to move to the nozzle plate as it moves to the ink groove position on the end side. It is possible to guide so as to press, and reliably prevent bubbles from remaining in the first common ink chamber.

  In the inkjet head according to an embodiment, the second plane is the second flow path port in the width in the one direction of the second common ink groove on a plane parallel to the plane including the one direction and the other direction. Is wider (continuously or stepwise) than the width at the position where the second plane intersects the outermost ink groove in the other direction.

  According to the ink jet head of this embodiment, the second plane is the second flow path port in the width of the second common ink groove on the plane parallel to the plane including the one direction and the other direction. The width of the second common ink groove facing the end of the ink groove is larger than the width of the second plane where the second plane intersects the outermost ink groove in the other direction. The side surface can be formed narrower toward the outermost ink groove than the second flow path port.

  For this reason, the side surface of the second common ink groove can guide the bubbles in the direction of the second flow path port, and the bubbles can be reliably discharged in the second common ink chamber.

  In the ink jet head according to the embodiment, the depth at the position where the second plane intersects the center of the second flow path opening in the depth of the second common ink groove on the plane orthogonal to the one direction is as follows. It is larger (continuously or stepwise) than the depth at the position where the second plane intersects the outermost ink groove in the other direction.

  According to the inkjet head of this embodiment, in the depth of the second common ink groove on the plane orthogonal to the one direction, the depth at the position where the second plane intersects the center of the second flow path port is as follows: Since the second plane is larger than the depth at the position where it intersects with the outermost ink groove in the other direction, the bottom surface of the second common ink groove facing the nozzle plate is located farthest from the second channel port. It can be formed shallower on the ink groove side.

  For this reason, when the nozzle hole is disposed downward (gravity direction) and ink is ejected downward, bubbles can be guided toward the second flow path port by the bottom surface of the second common ink groove. Air bubbles can be reliably discharged in the common ink chamber.

Moreover, in the inkjet head of one embodiment,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
At least one of the first flow path portion and the second flow path portion is linear.

  According to the ink jet head of this embodiment, since at least one of the first channel portion and the second channel portion is linear, it is possible to prevent bubbles from being trapped. On the other hand, when the flow path portion is formed in a polygonal line shape, a stepped shape, or the like, bubbles are trapped in that place, and unintended bubbles flow, causing unstable discharge.

Moreover, in the inkjet head of one embodiment,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
The inner surface of the cross section in at least one of the first channel portion and the second channel portion has a curved surface.

  According to the ink jet head of this embodiment, since the inner surface of the cross section of at least one of the first flow path portion and the second flow path portion has a curved surface, it is possible to prevent bubbles from being trapped. On the other hand, when the flow path portion is formed in a flat surface or a square shape, bubbles are trapped in that place, and unintended bubbles flow, causing unstable discharge.

  In one embodiment, the inner surface of the cross section of at least one of the first flow path portion and the second flow path portion is formed in a circular shape.

  According to the ink jet head of this embodiment, since the inner surface of the cross section of at least one of the first flow path portion and the second flow path portion is formed in a circle, the flow path portion can be easily processed. In addition, it is possible to reliably prevent trapping of bubbles.

Moreover, in the inkjet head of one embodiment,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
The cross-sectional areas of the first flow path part and the second flow path part are larger than the cross-sectional areas of the individual ink chambers.

  According to the ink jet head of this embodiment, the respective cross-sectional areas of the first flow path portion and the second flow path portion are larger than the cross-sectional areas of the individual ink chambers. Bubbles that flow into the common ink chamber through the same size are smoothly discharged through the channel opening.

  In one embodiment, the nozzle plate does not have a nozzle hole at a position corresponding to the outermost ink groove.

  According to the ink jet head of this embodiment, since the nozzle plate does not have a nozzle hole at a position corresponding to the outermost ink groove, many bubbles pass through the outermost ink groove. However, the above-mentioned endmost ink groove, which is unstable when the bubbles pass, is not used for ink discharge, and the reliability can be improved.

  Moreover, in the inkjet head of one Embodiment, the said main-body part consists of a some member.

  According to the ink jet head of this embodiment, since the main body portion is composed of a plurality of members, the cost for producing the members can be reduced. Moreover, it can be prevented by sealing the adhesive in a state where the adhesive sealing is insufficient due to the complicated shape, and leakage of the ink flow path can be reliably prevented.

  In one embodiment, the piezoelectric substrate is bonded and fixed to the main body via an elastic adhesive.

  Here, the elastic adhesive refers to an adhesive having a hardness of 70 or less in Shore D units. For example, “PM100” manufactured by Cemedine, “3065E” manufactured by ThreeBond, and Shin-Etsu Chemical Co., Ltd. "SIFEL610".

  According to the ink jet head of this embodiment, since the piezoelectric substrate is bonded and fixed to the main body portion via an elastic adhesive, even if the piezoelectric substrate and the main body portion are made of different materials, The elastic adhesive can absorb the difference in thermal expansion between the piezoelectric substrate and the main body, and can prevent a decrease in reliability of temperature change. On the other hand, when the elastic adhesive is not used, considering the cost, if the main body portion is formed using a metal or resin, the main body portion has a difference in thermal expansion coefficient from the piezoelectric substrate that is a ceramic. As a result, the material breaks down or leaks.

  In the ink jet head according to an embodiment, the piezoelectric substrate and the main body are formed of a single member that is integrally connected.

  According to the ink jet head of this embodiment, since the piezoelectric substrate and the main body are formed of a single member that is integrally connected, the cost can be reduced due to the trouble of combining a plurality of members, and a plurality of members can be used. It is possible to prevent a decrease in reliability of temperature change due to a difference in linear expansion coefficient between the members.

Moreover, in the inkjet head of one embodiment,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
A filter is communicated with each of the first channel portion and the second channel portion.

  According to the ink jet head of this embodiment, since the filter communicates with each of the first flow path part and the second flow path part, each flow path part is limited to the inlet or the outlet. Ink can be circulated. In this manner, ink can be circulated by reciprocating ink, and wasteful flow paths and costs can be reduced.

Moreover, in the inkjet head of one embodiment,
Each of the first channel port and the second channel port is provided,
The first flow path port is located at a substantially center in the other direction in the first common ink groove,
The second flow path port is located at the approximate center in the other direction in the second common ink groove.

  According to the ink jet head of this embodiment, the first flow path port is located at the approximate center of the first common ink groove in the other direction, and the second flow path port is formed in the second common ink groove. Since it is located at the approximate center in the other direction, the air bubbles mixed into the common ink chamber through the supply-side channel port of the first channel port and the second channel port are not biased and both The endmost ink groove can be passed, and the bubbles can be efficiently discharged.

Moreover, in the inkjet head of one embodiment,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The shortest distance between the bottom surface of the second common ink groove facing the nozzle plate and the nozzle plate is shorter than the shortest distance between the bottom surface of the ink groove facing the nozzle plate and the nozzle plate. large.

  According to the ink jet head of this embodiment, the shortest distance between the bottom surface of the second common ink groove facing the nozzle plate and the nozzle plate is the bottom surface of the ink groove facing the nozzle plate and the nozzle. Since it is larger than the shortest distance from the plate, when the nozzle hole is disposed downward (gravity direction) and ink is ejected downward, bubbles are subjected to buoyancy and the bottom surface of the ink groove and the second It moves along the bottom surface of the common ink groove.

  At this time, since the bottom surface of the second common ink groove is located on the buoyancy direction side with respect to the bottom surface of the ink groove, air bubbles passing through the individual ink chambers are discharged to the second common ink chamber. , Can prevent backflow.

Moreover, in the inkjet head of one embodiment,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
Is the shortest distance between the bottom surface of the first common ink groove facing the nozzle plate and the nozzle plate equal to the shortest distance between the bottom surface of the ink groove facing the nozzle plate and the nozzle plate? small.

  According to the ink jet head of this embodiment, the shortest distance between the bottom surface of the first common ink groove facing the nozzle plate and the nozzle plate is the bottom surface of the ink groove facing the nozzle plate and the nozzle. When the nozzle hole is disposed downward (gravity direction) and the ink is ejected downward, the bubbles are subjected to buoyancy to cause the bottom surface of the first common ink groove and It moves along the bottom surface of the ink groove.

  At this time, since the bottom surface of the ink groove is located on the buoyancy direction side with respect to the bottom surface of the first common ink groove, the individual ink chambers can be effectively produced without causing bubbles to stay in the first common ink chamber. Can be discharged.

Moreover, in the inkjet head of one embodiment,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The second flow path port is located on the bottom surface of the second common ink groove facing the nozzle plate.

  According to the ink jet head of this embodiment, since the second flow path port is located on the bottom surface of the second common ink groove facing the nozzle plate, the nozzle hole is disposed downward (gravity direction). When ink is ejected downward, the bubbles receive buoyancy and come into contact with the bottom surface of the second common ink groove.

  At this time, since the buoyancy direction received by the mixed bubbles is the same as the direction of the discharge outlet, the bubbles can be efficiently discharged from the second common ink chamber.

Moreover, in the inkjet head of one embodiment,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The main body has a first flow path part in which the first flow path port is an open end,
A filter is communicated with the first flow path portion.

  According to the ink jet head of this embodiment, since the filter communicates with the first flow path portion, the filter is disposed on the inflow port side to prevent dust from being mixed into the ink jet head. In addition to preventing bubbles from remaining, it is possible to prevent a decrease in the reliability of non-ejection occurrence due to dust.

  In addition, an ink jet head device of the present invention includes the above ink jet head.

  According to the inkjet head device of the present invention, since the inkjet head is provided, the ejection reliability can be improved.

  According to the inkjet head of the present invention, the main body has the first common ink groove communicating with the plurality of ink grooves on one end side of the plurality of ink grooves, and the other end side of the plurality of ink grooves. An area having a second common ink groove that communicates with a plurality of ink grooves, and an area where the first plane intersects the center of the first flow path port in an area where the first plane and the first common ink chamber intersect. However, since the first plane is larger than the area at the position where the outermost ink groove in the other direction intersects, the ink is smoothly circulated in the ink jet head, and the ink jet head is small without complicating it. In addition, it is possible to reliably eliminate bubbles.

  According to the inkjet head device of the present invention, since the inkjet head is provided, the ejection reliability can be improved.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a perspective view showing a first embodiment of an ink jet head according to the present invention. FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. FIG. 3 shows a state where the nozzle plate of the inkjet head is removed. As shown in FIGS. 1 to 3, the inkjet head 100 includes a piezoelectric substrate 1, a nozzle plate 2, and a main body 3.

  The piezoelectric substrate 1 has a plurality of ink grooves 6 on the upper surface which are separated from each other by a partition wall 20 and electrodes are provided on the inner wall. Each ink groove 6 extends in one direction (X-axis direction) and is open at both ends. The plurality of ink grooves 6 are arranged in parallel in the other direction (Y-axis direction) orthogonal to the one direction at intervals. For the sake of clarity, the number and depth of the ink grooves 6 are not accurately illustrated.

  Since the length of the piezoelectric substrate 1 in the one direction (X-axis direction) is the length of the ink groove 6, for example, when the length of the ink groove 6 is 5 mm, The length in the one direction (X-axis direction) may be 5 mm. The length of the piezoelectric substrate 1 in the other direction (Y-axis direction) varies depending on the number, width, and pitch of the ink grooves 6.

  Two piezoelectric materials whose polarization directions are opposite to each other at the approximate center in the depth direction of the ink groove 6 are bonded to the piezoelectric substrate 1 with an adhesive in advance. For example, a thin plate of 0.15 mm and a thick plate of 1.85 mm are pasted together. With this configuration, when a voltage is applied from the outside, the thin plate portion and the thick plate portion of the ink groove 6 are deformed in opposite directions, thereby generating a pressure that is a region surrounded by the ink groove 6 and the nozzle plate 2. Ink is ejected by changing the volume of the chamber.

  The main body 3 has a recess, and the piezoelectric substrate 1 is attached to the recess. The piezoelectric substrate 1 is bonded and fixed to the main body 3 via an elastic adhesive. Here, the elastic adhesive refers to an adhesive having a hardness of 70 or less in Shore D units. For example, “PM100” manufactured by Cemedine, “3065E” manufactured by ThreeBond, and Shin-Etsu Chemical Co., Ltd. "SIFEL610".

  The main body 3 includes a first member 3a and a second member 3b. The main body 3 has a first common ink groove 11 and a second common ink groove 21. The first common ink groove 11 communicates with the plurality of ink grooves 6 on one end side of the plurality of ink grooves 6. The second common ink groove 21 communicates with the plurality of ink grooves 6 on the other end side of the plurality of ink grooves 6.

  The nozzle plate 2 is disposed so as to cover the plurality of ink grooves 6, the first common ink groove 11 and the second common ink groove 21 from above, and together with the plurality of ink grooves 6, a plurality of individual ink chambers 6 a. The first common ink chamber 11 a is defined together with the first common ink groove 11, and the second common ink chamber 21 a is defined together with the second common ink groove 21. That is, the nozzle plate 2 is sized to seal the recess of the main body 3. The nozzle plate 2 has nozzle holes 8 at positions corresponding to the ink grooves 6.

  The contact surface side end portion of the nozzle plate 2 of the main body portion 3 needs not to protrude beyond the contact surface side end portion of the nozzle plate 2 in the partition wall 20 of the piezoelectric substrate 1. This is because the end portion of the main body portion 3 and the end portion of the partition wall 20 are simultaneously bonded to the nozzle plate 2, so that if the end portion of the main body portion 3 protrudes, the nozzle plate 2. Is lifted by the main body 3, and the nozzle plate 2 cannot be bonded to the end of the partition wall 20, that is, a region in which the individual ink chambers 6a are in communication is generated. If there is an area communicating with the individual ink chamber 6a, ink flows back and forth, and ink cannot be ejected efficiently, resulting in a decrease in speed.

  The main body 3 has a first flow path port 13a that communicates with the first common ink chamber 11a and a second flow path port 13b that communicates with the second common ink chamber 21a. Each of the first flow path port 13a and the second flow path port 13b is provided. The first channel port 13a is an ink inlet, and the second channel port 13b is an ink outlet. The main body 3 includes therein a first flow path portion 5a in which the first flow path port 13a is an open end and a second flow path section 5b in which the second flow path port 13b is an open end.

  The first flow path part 5a and the second flow path part 5b are linear. The inner surfaces of the cross sections of the first flow path part 5a and the second flow path part 5b have curved surfaces. That is, the inner surfaces of the cross sections of the first flow path portion 5a and the second flow path portion 5b are formed in a circular shape. The cross-sectional areas of the first flow path portion 5a and the second flow path portion 5b are larger than the cross-sectional areas of the individual ink chambers 6a.

  In the inkjet head 100, ink is supplied from a supply tank (not shown) to the first common ink chamber 11a via the first flow path portion 5a, and this ink passes through the individual ink chambers 6a. Then, it flows into the second common ink chamber 21a and flows to the waste liquid tank through the second flow path portion 5b.

  On the other hand, in the ejection of ink, the partition wall 20 is sheared and deformed by the voltage applied to the electrode of the ink groove 6, the volume of the individual ink chamber 6 a is deformed, and the ink is ejected from the nozzle hole 8. .

  Here, the inkjet head 100 is used, for example, such that the nozzle hole 8 is disposed downward (gravity direction) and ink is ejected downward from the nozzle hole 8. That is, the inkjet head 100 is used with the Z-axis direction facing downward.

  The nozzle hole 8 is located at the center in the longitudinal direction (X-axis direction) of the ink groove 6. This is because, when the nozzle hole 8 is located at the center in the longitudinal direction of the ink groove 6, when a voltage is applied to the ink groove 6 by an external voltage application mechanism, the propagation efficiency of the pressure wave by the ink groove 6 is increased. This is because the ink can be discharged at a low discharge voltage.

  The nozzle plate 2 has no nozzle hole 8 at a position corresponding to the outermost ink groove 6 in the other direction (Y-axis direction). The ink groove 6 (dummy groove) without the nozzle hole 8 is not limited to one at both ends. However, if the flow resistance is different from other ink grooves, the ink does not flow on average in each ink groove, so the ink groove without nozzle holes has the same flow resistance as the ink groove with nozzle holes, that is, The same channel cross-sectional area and the same channel length are required.

  As shown in FIG. 4, the piezoelectric substrate 1 has an electrode lead portion 9 formed on one side surface portion (end surface portion) thereof. The electrode lead-out portion 9 is electrically connected to the electrode 7 provided on the inner surface of the ink groove 6. A flexible cable 4 is connected to the electrode lead-out portion 9. In FIG. 4, the electrode 7 and the electrode lead-out portion 9 are indicated by oblique lines.

  As shown in FIG. 2, the flexible cable 4 is located on the joint surface between the first member 3a and the second member 3b. That is, the joint surface of the second member 3b has a recess into which the flexible cable 4 is fitted.

  The electrode lead portion 9 is applied with a voltage from the outside via the flexible cable 4, and the applied voltage is transmitted to the electrode 7 of the ink groove 6 that is in conduction with the electrode lead portion 9. Due to the voltage applied to the electrode 7, the wall surface of the ink groove 6 of the piezoelectric substrate 1 is sheared and deformed, the volume of the individual ink chamber 6 a is deformed, and the ejected ink is ejected from the nozzle hole 8. .

  As shown in FIG. 5, in the area where the first plane S1 orthogonal to the other direction (Y-axis direction) and the first common ink chamber 11a intersect, the first plane S1 is the center of the first flow path port 13a. Is larger than the area at the position where the first plane S1 intersects the ink groove 6 (dummy groove 6b) at the extreme end in the other direction. That is, this area decreases stepwise or continuously from the first flow path port 13a to the dummy groove 6b.

  In the area where the second plane S2 perpendicular to the other direction (Y-axis direction) and the second common ink chamber 21a intersect, the area at the position where the second plane S2 intersects the center of the second flow path port 13b is The area of the second plane S2 is larger than the area at the position where the second end S2 intersects the ink groove 6 (dummy groove 6b) in the other end. That is, this area decreases stepwise or continuously from the second flow path port 13b to the dummy groove 6b.

  At least a part of the side surface 11b of the first common ink groove 11 facing the end of the ink groove 6 is formed as a concave curved surface. At least a part of the side surface 21b of the second common ink groove 21 facing the end of the ink groove 6 is formed as a concave curved surface.

  More specifically, the first common ink groove 11 has a width L in the one direction on a plane parallel to a plane including the one direction (X-axis direction) and the other direction (Y-axis direction). The width at the position where one plane S1 intersects the center of the first flow path port 13a is larger than the width at the position where the first plane S1 intersects the ink groove 6 (dummy groove 6b) at the extreme end in the other direction. That is, the width L is reduced stepwise or continuously from the first flow path port 13a to the dummy groove 6b.

  In the width L in the one direction of the second common ink groove 21 on a plane parallel to the plane including the one direction (X-axis direction) and the other direction (Y-axis direction), the second plane S2 is the first plane. The width at the position intersecting the center of the two flow path ports 13b is larger than the width at the position where the second plane S2 intersects the outermost ink groove 6 (dummy groove 6b) in the other direction. That is, the width L is reduced stepwise or continuously from the second flow path port 13b to the dummy groove 6b.

  Here, in comparison with the flow path resistance by each ink groove, the flow path resistance from the flow path port to the opening end of the ink groove has a large difference between the ink groove at the center and the ink groove at the end. The position of the meniscus in the nozzle hole changes, and variations in ink grooves occur in the discharge speed and discharge volume.

  If the difference in flow path resistance between the ink grooves due to the shape of the common ink chamber is about 1/10 or less of the flow path resistance of the ink grooves, the ink discharge characteristic variation that originally exists between the ink grooves is buried. . For this reason, the shape of the common ink chamber is preferably a shape that takes into account the flow path resistance of each ink groove.

  As shown in FIGS. 5 and 6, at the depth D of the second common ink groove 21 on the plane orthogonal to the one direction (X-axis direction), the second plane S2 is the second flow path port 13b. The depth at the position that intersects the center is the same as the depth at the position where the second plane S2 intersects the ink groove 6 (dummy groove 6b) at the extreme end in the other direction.

  In the depth D of the first common ink groove 11 on the plane orthogonal to the one direction (X-axis direction), the depth at the position where the first plane S1 intersects the center of the first flow path port 13a is the depth described above. The first plane S1 is the same as the depth at the position where it intersects the outermost ink groove 6 (dummy groove 6b) in the other direction.

  As shown in FIG. 2, at least a part of the boundary surface between the side surface 11b of the first common ink groove 11 and the bottom surface 11c of the first common ink groove 11 facing the nozzle plate 2 is a concave curved surface. Is formed. At least a part of the boundary surface between the side surface 21b of the second common ink groove 21 and the bottom surface 21c of the second common ink groove 21 facing the nozzle plate 2 is formed as a concave curved surface.

  As shown in FIG. 2 and FIG. 5, the first flow path port 13a is located at the approximate center in the other direction (Y-axis direction) of the first common ink groove 11, and the second flow path port 13b is The second common ink groove 21 is located approximately at the center in the other direction. The second flow path port 13 b is located on the bottom surface 21 c of the second common ink groove 21. A filter 14 communicates with the first flow path portion 5a.

  The shortest distance between the bottom surface 21 c of the second common ink groove 21 and the nozzle plate 2 is larger than the shortest distance between the bottom surface of the ink groove 6 and the nozzle plate 2. The shortest distance between the bottom surface 11 c of the first common ink groove 11 and the nozzle plate 2 is equal to or smaller than the shortest distance between the bottom surface of the ink groove 6 and the nozzle plate 2.

  Next, the movement of bubbles when bubbles are mixed in the ink jet head having the above-described configuration will be described with reference to FIGS. 7A to 7E.

  First, as shown in FIG. 7A, the bubbles 15 indicated by oblique lines enter the first common ink chamber 11a through the first flow path port 13a.

  Thereafter, as shown in FIG. 7B, since the flow path resistance in the flow path of the ink groove 6 is higher than the flow path in the first common ink chamber 11a, the bubbles 15 collide with the opening end 16 of the ink groove 6. Even if it is in a state, it does not enter the ink groove 6.

  Then, as shown in FIG. 7C, due to the difference in flow path resistance, the bubble 15 moves to the opening end 16 of the outermost ink groove 6 (dummy groove 6b), which is far from the first flow path port 13a. .

  Thereafter, as shown in FIG. 7D, the bubble 15 is pushed as it is toward the opening end 16 of the outermost ink groove 6.

  At this time, since the side surface 11b of the first common ink groove 11 is a smooth shape having a curved surface, the bubble 15 pushed into the opening end 16 is not caught by the side surface 11b, and the bubble 15 is trapped. Can be prevented.

  In addition, since the first flow path port 13a is located at a substantially central portion in the Y direction of the first common ink groove 11, the bubbles 15 are distributed to the outermost ink groove 6 without being biased, and the bubbles are efficiently collected. 15 can be discharged.

  Further, the width of the first common ink groove 11 in the X-axis direction is continuously reduced from the first flow path port 13a to the dummy groove 6b. That is, the shape of the side surface 11b of the first common ink groove 11 is a shape that is guided so as to be pressed against the opening end 16 as the bubble 15 moves toward the dummy groove 6b. Accordingly, the bubbles 15 can be passed through the ink groove 6 without remaining in the first common ink chamber 11a, and the bubbles 15 can be prevented from remaining in the first common ink chamber 11a.

  As shown in FIG. 7E, the bubbles 15 discharged to the second common ink chamber 21a through the ink groove 6 collide with the side surface 21b of the second common ink groove 21 to be guided. It goes to the second flow path port 13b. At this time, since the bubbles 15 form one bubble with the size passing through the ink groove 6, the second channel port 13 b has a channel larger than the channel cross-sectional area in the ink groove 6. By having the cross-sectional area, the bubbles 15 can be discharged smoothly.

  Next, a method for manufacturing the ink jet head having the above configuration will be described.

  First, as shown in FIG. 8A, a groove forming step is performed. That is, a plurality of ink grooves 6 are formed by scanning the dicing blade on the piezoelectric substrate 1 that is an actuator member a plurality of times in a certain direction (X-axis direction). Here, the piezoelectric substrate 1 having a size of 5 mm × 50 mm and a thickness of 2 mm was used. The depth of the ink grooves 6 was about 300 μm, the width was 100 μm, the pitch of the ink grooves 6 was about 200 μm, and the number of ink grooves 6 was 200. The width of the ink groove 6 can be changed by the thickness of the dicing blade to be used, and the depth of the ink groove 6 can be changed by changing the cutting amount of the dicing blade.

  Thereafter, as shown in FIG. 8B, a conductive film forming step is performed. That is, a conductive film to be an electrode is formed on the inner wall of the ink groove 6 of the piezoelectric substrate 1, and a conductive film to be an electrode leading portion is formed on the side surface of the piezoelectric substrate 1.

  In this embodiment, copper is formed by sputtering. The film thickness on the inner wall of the copper ink groove 6 formed at this time was set to 0.5 μm at the thinnest portion. Note that the hatched portion is a portion where a conductive film is formed.

  In the conductive film forming step by sputtering in this embodiment, the conductive film is formed on the entire surface except the surface on the back side of the surface where the ink grooves 6 of the piezoelectric substrate 1 are formed. Is done. At this time, the thickness of the copper film formed on the side surface of the piezoelectric substrate 1 where the ink groove 6 opens was 1 μm. The film thickness of the copper film formed on the inner wall of the ink groove 6 and the film thickness of the copper film formed on the side surface of the piezoelectric substrate 1 where the ink groove 6 opens differ from each other in the area around the copper depending on the shape. This is due to the difference.

  Then, as shown in FIG. 8C, a removal process is performed. That is, the unnecessary conductive film on the surface of the piezoelectric substrate 1 where the ink grooves 6 are formed is removed. This removal step can be performed, for example, by scanning the upper surface of the piezoelectric substrate 1 a plurality of times with a dicing blade. At this time, it is preferable that the surface of the piezoelectric substrate 1 is slightly ground with a dicing blade so that the ink grooves 6 adjacent to each other on the ink groove 6 forming surface of the piezoelectric substrate 1 are surely insulated. On the piezoelectric substrate 1 after the removal step, an electrode 7 is formed on the inner wall of the ink groove 6, and a conductive film is formed on the side surface of the piezoelectric substrate 1.

  Thereafter, as shown in FIG. 8D, a separation step is performed. That is, the separation groove 12 is formed by scanning the conductive film formed on the side surface of the piezoelectric substrate 1 with a dicing blade a plurality of times in a fixed direction (Z-axis direction). By this separation step, electrode lead portions 9 corresponding to the ink grooves 6 are formed.

  At this time, as shown in FIG. 4, the electrode 7 formed on the inner wall of the ink groove 6 and the electrode lead-out portion 9 are electrically connected on the side surface of the piezoelectric substrate 1 where the ink groove 6 opens. In this embodiment, the separation groove 12 has a depth of 10 μm and a width of 50 μm, and the separation step is performed on each side surface of the piezoelectric substrate 1 where the ink grooves 6 are opened. Further, the portion where the separation groove 12 is formed is between the ink grooves 6 and is located at a position where there is no electrical conduction between the adjacent ink grooves 6. Such a separation process was performed on both sides of the side surface of the piezoelectric substrate 1 where the ink grooves 6 are open. By performing the separation process on both sides, the piezoelectric substrate 1 becomes symmetrical, so that the direction is not mistaken in the subsequent process. Further, when the electrode lead portion 9 on one side is damaged, the yield can be improved because the electrode lead portion 9 on the opposite side can be used.

  A conductive member is connected to the electrode lead portion 9 of the piezoelectric substrate 1 thus processed. As shown in FIG. 4, in this embodiment, the flexible cable 4 is used as the conductive member, and the connection with the electrode lead-out portion 9 is an ACF connection. The other end of the flexible cable 4 is connected to an external voltage application mechanism directly or via another member in order to eject ink. In this embodiment, the reason why the flexible cable is used as the conductive member is that the flexible cable is easy to be deformed and can be easily used in the process in the subsequent process and can suppress a decrease in yield. There is no.

  Then, as illustrated in FIG. 8F, the piezoelectric substrate 1 is bonded to the first member 3 a of the main body 3. An elastic adhesive was applied to the bonding surface between the first member 3 a and the piezoelectric substrate 1 and pressed against the piezoelectric substrate 1.

  Thereafter, as shown in FIG. 3, an elastic adhesive was similarly applied to the bonding surface between the first member 3a and the second member 3b, and the second member 3b was pressed against the first member 3a. This state was maintained at room temperature for 24 hours for adhesion.

  Since the second member 3b is provided with a cover so that the connecting portion between the flexible cable 4 and the electrode lead-out portion 9 is not exposed to ink, the connecting portion between the flexible cable 4 and the electrode lead-out portion 9 is a common ink chamber. It becomes the composition which becomes the outside. By providing the cover in this manner, even when the conductive ink is used, the conductive ink is not in contact with the connection portion between the flexible cable 4 and the electrode lead-out portion 9, so that there is no electrical short circuit.

  Thereafter, as shown in FIG. 1, the nozzle plate 2 is bonded so as to cover the ink groove 6 to complete the ink jet head.

  According to the ink jet head having the above-described configuration, the main body 3 has the first common ink groove 11 communicating with the plurality of ink grooves 6 on one end side of the plurality of ink grooves 6 and the plurality of ink grooves 6. Since the second common ink groove 21 communicated with the plurality of ink grooves 6 is provided on the other end side, the width and depth of the first common ink groove 11 and the second common ink groove 21 are appropriately adjusted. The flow resistance of the first common ink groove 11 and the second common ink groove 21 can be made sufficiently smaller than the flow resistance of the individual ink chamber 6a, and it passes through the individual ink chamber 6a in the ink jet head. Ink flow can be facilitated easily. In addition, the number of ink jet heads that can be obtained from one wafer-like piezoelectric substrate 1 (so-called “number of picks”) is not affected at all.

  In addition, in the area where the first plane S1 and the first common ink chamber 11a intersect, the area where the first plane S1 intersects the center of the first flow path port 13a is the first plane S1 is the other. Since the area at the position intersecting with the ink groove 6 at the extreme end in the direction is larger, the bubbles 15 mixed into the first common ink chamber 11a from the first flow path port 13a initially have the high flow path resistance. 6, after striking the end of the piezoelectric substrate 1 without passing through 6, it moves to the end in the other direction far from the first flow path port 13a and tries to stay there. When moving to the ink groove 6 position, the bubble 15 can be passed through the ink groove 6 by pushing into the end region while changing the shape of the bubble 15, and the bubble in the first common ink chamber 11a can be passed. 15 Remaining can be prevented.

  In other words, when the bubbles 15 are trapped, the ejection parameters become unstable or cause non-ejection due to the unintended bubbles 15 flowing, but the bubbles 15 are not in the first common ink chamber 11a. By preventing the bubbles 15 from remaining, it is possible to provide an inkjet head with high ejection reliability that prevents unintended bubbles 15 from flowing during ejection.

  Therefore, it is possible to realize an ink jet head that can smoothly circulate ink in the ink jet head, can be downsized without complicating the ink jet head, and can reliably eliminate the bubbles 15.

  Further, the area at the position where the second plane S2 intersects the center of the second flow path port 13b is larger than the area at the position where the second plane S2 intersects the ink groove 6 at the extreme end in the other direction. The bubbles 15 flowing into the second common ink chamber 21a through the first common ink chamber 11a and the ink groove 6 move so as to be guided in the direction of the second flow path port 13b having a large cross-sectional area. In the second common ink chamber 21a, the bubbles 15 can be effectively discharged, and the bubbles 15 can be prevented from remaining.

  Further, since at least a part of the side surface 11b of the first common ink groove 11 is formed in a concave curved surface, the bubbles 15 are caused to be formed into the ink groove 6 on the end side by the side surface 11b of the first common ink groove 11. When guided so as to be pressed against the piezoelectric substrate 1 as it moves to the position, the bubbles 15 are prevented from remaining on the side surface 11b of the first common ink groove 11 without being trapped by planes or corners. can do.

  Further, since at least a part of the side surface 21b of the second common ink groove 21 is formed in a concave curved surface, the side surface 21b of the second common ink groove 21 causes the bubbles 15 to be in the ink groove 6 on the end side. When guided so as to be pressed against the piezoelectric substrate 1 as it moves to the position, the bubbles 15 are prevented from remaining on the side surface 21b of the second common ink groove 21 without being trapped by planes or corners. can do.

  In addition, since at least a part of the boundary surface between the side surface 11b of the first common ink groove 11 and the bottom surface 11c of the first common ink groove 11 is formed as a concave curved surface, bubbles 15 are formed on the boundary surface. It is possible to discharge the bubbles 15 without stagnation.

  In addition, since at least a part of the boundary surface between the side surface 21b of the second common ink groove 21 and the bottom surface 21c of the second common ink groove 21 is formed as a concave curved surface, bubbles 15 are formed on the boundary surface. It is possible to discharge the bubbles 15 without stagnation.

  Further, the first plane S1 intersects the center of the first flow path port 13a in the width L in the one direction of the first common ink groove 11 on a plane parallel to the plane including the one direction and the other direction. Since the width at the position is larger than the width at the position where the first plane S1 intersects the ink groove 6 at the extreme end in the other direction, the first common ink groove 11 facing the end of the ink groove 6 is formed. The side surface 11b can be formed narrower toward the outermost ink groove 6 side than the first flow path port 13a.

  For this reason, the side surface 11b of the first common ink groove 11 can guide the bubble 15 so as to be pressed against the piezoelectric substrate 1 as it moves to the position of the ink groove 6 on the end side, so that the first common ink chamber 11a can be guided. It is possible to reliably prevent the bubbles 15 from remaining inside.

  Further, the second plane S2 intersects the center of the second flow path port 13b in the width L in the one direction of the second common ink groove 21 on a plane parallel to the plane including the one direction and the other direction. Since the width at the position is larger than the width at the position where the second plane S2 intersects the outermost ink groove 6 in the other direction, the width of the second common ink groove 21 facing the end of the ink groove 6 is larger. The side surface 21b can be formed narrower toward the ink groove 6 side than the second flow path port 13b.

  For this reason, the bubbles 15 can be guided toward the second flow path port 13b by the side surface 21b of the second common ink groove 21, and the bubbles 15 can be reliably discharged in the second common ink chamber 21a.

  Further, since at least one of the first flow path portion 5a and the second flow path portion 5b is linear, it is possible to prevent the bubbles 15 from being trapped. On the other hand, when the flow path portion is formed in a polygonal line shape or a stepped shape, the bubbles 15 are trapped in the place, and the unintended bubbles 15 flow to cause unstable discharge.

  Moreover, since the inner surface of the cross section in at least one of the first channel portion 5a and the second channel portion 5b has a curved surface, it is possible to prevent the bubbles 15 from being trapped. On the other hand, when the flow path portion is formed in a flat surface or a square shape, the bubbles 15 are trapped in the place, and the unintended bubbles 15 flow to cause unstable discharge.

  Further, since the inner surface of the cross section of at least one of the first flow path portion 5a and the second flow path portion 5b is formed in a circular shape, the flow path portion can be easily processed, and the trap of the bubbles 15 can be obtained. Can be reliably prevented.

  Further, the cross-sectional area of each of the first flow path portion 5a and the second flow path portion 5b is larger than the cross-sectional area of the individual ink chambers 6a. The bubbles 15 that have flowed into the ink chamber have the same size and are smoothly discharged through the channel opening.

  Further, since the nozzle plate 2 does not have the nozzle hole 8 at a position corresponding to the outermost ink groove 6, many bubbles 15 pass through the outermost ink groove 6. However, the ink groove 6 at the end, which becomes unstable when the bubble 15 passes, is not used for ink discharge, and the reliability can be improved.

  Moreover, since the said main-body part 3 consists of a some member, the cost of member preparation can be reduced. Moreover, it can be prevented by sealing the adhesive in a state where the adhesive sealing is insufficient due to the complicated shape, and leakage of the ink flow path can be reliably prevented.

  Further, since the piezoelectric substrate 1 is bonded and fixed to the main body 3 via an elastic adhesive, even if the piezoelectric substrate 1 and the main body 3 are made of different materials, the elastic adhesive The difference in thermal expansion between the piezoelectric substrate 1 and the main body 3 can be absorbed to prevent the reliability of temperature change from being lowered. On the other hand, when the elastic adhesive is not used, if the main body 3 is formed using metal or resin in consideration of cost, the main body 3 is thermally expanded with the piezoelectric substrate 1 which is ceramic. The difference in coefficient increases, causing member destruction and leakage.

  In addition, the first flow path port 13 a is positioned at the approximate center of the first common ink groove 11 in the other direction, and the second flow path port 13 b is approximately the other direction of the second common ink groove 21. Since it is located in the center, the air bubbles 15 mixed into the common ink chamber through the supply-side flow channel port of the first flow channel port 13a and the second flow channel port 13b are not biased, and are The ink groove 6 at the end can be passed, and the bubbles 15 can be discharged efficiently.

  The shortest distance between the bottom surface 21 c of the second common ink groove 21 facing the nozzle plate 2 and the nozzle plate 2 is the bottom surface of the ink groove 6 facing the nozzle plate 2 and the nozzle plate 2. When the nozzle hole 8 is disposed downward (in the direction of gravity) and ink is ejected downward, the bubbles 15 receive buoyancy and receive the bottom surface of the ink groove 6 and the above. It moves along the bottom surface 21 c of the second common ink groove 21.

  At this time, since the bottom surface 21c of the second common ink groove 21 is located on the buoyancy direction side with respect to the bottom surface of the ink groove 6, the bubbles 15 passing through the individual ink chambers 6a are moved into the second common ink chamber. It is possible to prevent reverse flow after being discharged to 21a.

  The shortest distance between the bottom surface 11 c of the first common ink groove 11 facing the nozzle plate 2 and the nozzle plate 2 is the bottom surface of the ink groove 6 facing the nozzle plate 2 and the nozzle plate 2. When the nozzle hole 8 is disposed downward (in the direction of gravity) and ink is ejected downward, the bubbles 15 receive buoyancy and receive the buoyancy. It moves along the bottom surface 11 c and the bottom surface of the ink groove 6.

  At this time, since the bottom surface of the ink groove 6 is located on the buoyancy direction side of the bottom surface 11c of the first common ink groove 11, it is effective without causing the bubbles 15 to stay in the first common ink chamber 11a. The individual ink chamber 6a can be discharged.

  Further, since the second flow path port 13b is located on the bottom surface 21c of the second common ink groove 21 facing the nozzle plate 2, the nozzle hole 8 is disposed downward (gravity direction) so that the ink is directed downward. In the case of discharging to the bubble 15, the bubble 15 receives buoyancy and contacts the bottom surface 21 c of the second common ink groove 21.

  At this time, since the buoyancy direction received by the mixed bubbles 15 is the same as the direction of the discharge outlet, the bubbles 15 can be efficiently discharged from the second common ink chamber 21a.

  In addition, since the filter 14 is communicated with the first flow path portion 5a, the filter 14 is disposed on the inlet side to prevent the bubbles 15 from remaining by preventing dust from being mixed into the inkjet head. In addition to preventing, it is possible to prevent a decrease in reliability of non-ejection occurrence due to dust.

  In this embodiment, copper is used as an electrode, but any conductive material may be used. Furthermore, although the conductive film forming step is performed by a sputtering method, it has been confirmed that a similar conductive film can be formed by an ion plating method or an electroless plating method. The ion plating method can form a conductive film with good adhesion, and the electroless plating method forms a conductive film with a small film thickness variation even on the piezoelectric substrate 1 on which a plurality of complicated groove shapes are formed. can do. On the other hand, it has been found that the vapor phase growth method and the vapor deposition method are not suitable because the substrate surface temperature of the piezoelectric substrate 1 tends to increase. This is because the piezoelectric characteristics of the piezoelectric material deteriorate at high temperatures. It was confirmed that even an ink jet head formed by using an ion plating method or an electroless plating method in the conductive film forming step has a discharge performance equivalent to that of the ink jet head formed by the sputtering method.

  In this embodiment, the removal step is performed after the conductive film formation step. However, before the conductive film formation step, a portion where the conductive film is not desired to be formed is covered with a resist material in advance to form the conductive film. The resist material may be peeled off after the process.

In the separation step, the separation grooves 12 are formed by the dicing blade, but machining other than the dicing blade such as a wire saw may be performed. Furthermore, not the separation by the dicing blade, the ejection performance similar to the ink jet head separated by the dicing blade is also applied to the ink jet head in which the unnecessary portion of the conductive film is removed by YAG laser irradiation and the electrode lead portion 9 is formed. It was confirmed that it has circulation performance. Regarding the type of laser, it is not necessary to be a YAG laser. For example, using a CO ₂ laser or an excimer laser, it is confirmed that the electrode lead portion 9 can be formed by separating the conductive film on the side surface of the piezoelectric substrate 1. did.

  In addition, the connection method between the electrode lead-out portion 9 and the conductive member is ACF connection in this embodiment. However, the connection method is not limited to this, and it was confirmed that the connection can be achieved using a conductive paste such as silver paste or solder. . However, when the thickness of the piezoelectric substrate 1 is thin, there is a possibility that the conductive paste or solder applied to the electrode lead-out portion 9 may flow into the groove 6. Therefore, the length obtained by subtracting the depth of the groove 6 from the thickness of the piezoelectric substrate 1. That is, it is preferable to use a conductive paste or solder only when the length capable of connecting a conductive member such as the flexible cable 4 to the electrode lead portion 9 is at least 1.5 mm.

  Further, the steps described in this embodiment are the minimum necessary steps, and steps other than those described above may be added as necessary. For example, a step of machining a groove as a mark for making a processing reference somewhere on the piezoelectric substrate 1 or a step of covering the electrode 7 with a protective film when the electrode 7 corrodes due to contact with ink is added. May be.

(Second Embodiment)
FIG. 9 shows a second embodiment of the inkjet head of the present invention. If the point which is different from the said 1st Embodiment is demonstrated, in this 2nd Embodiment, there are many quantities of a flow-path opening. Since other structures are the same as those of the first embodiment, description thereof is omitted.

  That is, in the inkjet head 200 of the second embodiment, two first flow path ports 13a and two second flow path ports 13b are provided. Thus, even when there are a plurality of the first flow path ports 13a and the second flow path ports 13b, the same effect as that of the first embodiment is exhibited in discharging bubbles.

(Third embodiment)
FIG. 10 shows a third embodiment of the ink jet head of the present invention. The difference from the first embodiment will be described. In the third embodiment, the shapes of the first common ink groove and the second common ink groove are different. Since other structures are the same as those of the first embodiment, description thereof is omitted.

  That is, in the inkjet head 300 according to the third embodiment, at least a part of the bottom surface 11c of the first common ink groove 11 is formed in a concave curved surface. At least a part of the bottom surface 21c of the second common ink groove 21 is formed in a concave curved surface.

  Specifically, in the depth of the first common ink groove 11 on the plane orthogonal to the one direction (X-axis direction), the depth at the position where the first plane S1 intersects the center of the first flow path port 13a. However, it is larger than the depth at the position where the first plane S1 intersects the ink groove 6 (dummy groove 6b) at the extreme end in the other direction (Y-axis direction). That is, this depth decreases stepwise or continuously from the first flow path port 13a to the dummy groove 6b.

  In the depth of the second common ink groove 21 on the plane orthogonal to the one direction (depth D in FIG. 6), the depth at the position where the second plane S2 intersects the center of the second flow path port 13b is the above-described depth. The second plane S2 is larger than the depth at the position where it intersects the ink groove 6 (dummy groove 6b) at the extreme end in the other direction. That is, this depth decreases stepwise or continuously from the second flow path port 13b to the dummy groove 6b.

  According to the ink jet head having the above-described configuration, since at least a part of the bottom surface 11c of the first common ink groove 11 is formed in a concave curved surface, the nozzle hole 8 is disposed downward (in the direction of gravity) so that the ink is directed downward. When the bubbles 15 are subjected to buoyancy and are pressed against the bottom surface 11c of the first common ink groove 11 on the opposite side in the direction of gravity, the bubbles 15 are not trapped by a flat surface or a step. Remaining at the bottom surface 11c of the first common ink groove 11 can be prevented.

  In addition, since at least a part of the bottom surface 21c of the second common ink groove 21 is formed as a concave curved surface, when the nozzle hole 8 is disposed downward (gravity direction) and ink is ejected downward, the bubble 15 However, when the buoyancy is applied to the bottom surface 21c of the second common ink groove 21 opposite to the direction of gravity, the bubbles 15 are not trapped by a flat surface or a step, and the bubbles 15 It is possible to prevent remaining at the bottom surface 21c.

  Further, in the depth of the first common ink groove 11 on the plane orthogonal to the one direction, the depth at the position where the first plane S1 intersects the center of the first flow path port 13a is the first plane S1. Is larger than the depth at the position where the ink groove 6 at the outermost end in the other direction intersects, the bottom surface 11c of the first common ink groove 11 facing the nozzle plate 2 is located farthest from the first flow path port 13a. It can be formed shallower toward the end of the ink groove 6 side.

  Therefore, when the nozzle hole 8 is disposed downward (gravity direction) and ink is ejected downward, the bubble 15 is moved to the ink groove position on the end side by the bottom surface 11c of the first common ink groove 11. As a result, it can be guided so as to be pressed against the nozzle plate 2, and the remaining of the bubbles 15 in the first common ink chamber 11a can be reliably prevented.

  Further, in the depth of the second common ink groove 21 on the plane orthogonal to the one direction, the depth at the position where the second plane S2 intersects the center of the second flow path port 13b is the second plane S2. Is larger than the depth at the position where the ink groove 6 intersects with the outermost ink groove 6 in the other direction, the bottom surface 21c of the second common ink groove 21 facing the nozzle plate 2 is located farthest from the second flow path port 13b. It can be formed shallower toward the end of the ink groove 6 side.

  Therefore, when the nozzle hole 8 is disposed downward (gravity direction) and ink is ejected downward, the bubble 15 can be guided toward the second flow path port 13b by the bottom surface 21c of the second common ink groove 21. Thus, the bubbles 15 can be reliably discharged in the second common ink chamber 21a.

(Fourth embodiment)
FIG. 11 shows a fourth embodiment of the inkjet head of the present invention. The difference from the first embodiment will be described. In the fourth embodiment, the shapes of the first common ink groove and the second common ink groove are different. Since other structures are the same as those of the first embodiment, description thereof is omitted.

  That is, in the inkjet head 400 of the fourth embodiment, at least a part of the side surface 11b and the bottom surface 11c of the first common ink groove 11 is formed in a concave curved surface. At least a part of the side surface 21b and the bottom surface 21c of the second common ink groove 21 is formed as a concave curved surface.

  In short, the shapes of the first common ink groove and the second common ink groove of the inkjet head 400 are the same as the shapes of the first common ink groove and the second common ink groove of the inkjet head 100 of the first embodiment. This is a shape obtained by adding the shapes of the first common ink groove and the second common ink groove of the inkjet head 300 of the third embodiment.

  Therefore, the fourth embodiment has the effects of the first embodiment and the effects of the third embodiment.

(Fifth embodiment)
FIG. 12 shows a fifth embodiment of the inkjet head of the present invention. The difference from the first embodiment will be described. In the fifth embodiment, the positions of the first flow path port and the filter are different. Since other structures are the same as those of the first embodiment, description thereof is omitted.

  That is, in the inkjet head 500 according to the fifth embodiment, the first flow path port 13 a is located on the bottom surface 11 c of the first common ink groove 11. In addition, the filter 14 is communicated with each of the first flow path portion 5a in which the first flow path port 13a is an open end and the second flow path portion 5b in which the second flow path port 13b is an open end.

  Therefore, since the filter 14 is connected to each of the first flow path portion 5a and the second flow path portion 5b, the flow path portions 5a and 5b are not limited to the inlet and the outlet. Ink can be circulated. In this manner, ink can be circulated by reciprocating ink, and wasteful flow paths and costs can be reduced.

  When ink circulation is not necessary, both the flow path portions 5a and 5b may be connected to a common supply tank to supply ink. Further, when the discharged ink is returned to the inkjet head once again and circulated for use, both the flow path portions 5a and 5b are connected to a common tank or connected to one flow path portion 5a. A connection is made between the supply tank and the waste liquid tank connected to the other flow path portion 5b so that the ink can move.

(Sixth embodiment)
FIG. 13 shows an embodiment of the ink jet head device of the present invention. This inkjet head device is, for example, a printer. The ink jet head device 700 includes the ink jet head 600 according to any one of the first to fifth embodiments.

  The inkjet head device 700 includes a box body 703, a sheet guide 704 attached to the box body 703, and a holding shaft 705 attached to the box body 703. The inkjet head 600 is attached to the holding shaft 705 so as to be able to travel in the direction of the arrow. In the box 703, a conveyance roller (not shown), an ink supply / discharge unit, and a control unit are attached. The control unit receives image data transmitted from an image processing apparatus such as a computer (not shown), and controls the members to perform printing.

  The inkjet head device 700 receives and processes image data transmitted from an external information processing device (such as a computer or a digital camera), and prints and outputs the image on a printing sheet made of paper, plastic, or the like. .

  According to the ink jet head device having the above configuration, since the ink jet head 600 is provided, the ejection reliability can be improved.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the piezoelectric substrate and the main body portion may be formed of a single member that is integrally connected, thereby reducing the cost of labor of combining a plurality of members and due to the difference in linear expansion coefficient between the plurality of members. A decrease in reliability of temperature change can be prevented. Further, the main body portion may be an integral type, or may be formed of three or more members.

1 is a perspective view showing a first embodiment of an inkjet head of the present invention. It is A-A 'sectional drawing of FIG. It is a perspective view of the inkjet head which shows the state which removed the nozzle plate. It is a perspective view of a piezoelectric substrate and a flexible cable. It is a top view of the inkjet head which shows the state which removed the nozzle plate. It is a perspective view of the 2nd member of a main-body part. It is a top view explaining the 1st time-dependent change at the time of a bubble mixing in an ink jet head. It is a top view explaining the 2nd time-dependent change at the time of a bubble mixing in an ink jet head. It is a top view explaining the 3rd time-dependent change at the time of a bubble mixing in an ink jet head. It is a top view explaining the 4th time-dependent change at the time of a bubble mixing in an ink jet head. It is a top view explaining the 5th time-dependent change at the time of a bubble mixing in an ink jet head. It is a perspective view explaining the 1st process of the manufacturing method of an inkjet head. It is a perspective view explaining the 2nd process of the manufacturing method of an inkjet head. It is a perspective view explaining the 3rd process of the manufacturing method of an inkjet head. It is a perspective view explaining the 4th process of the manufacturing method of an inkjet head. It is a perspective view explaining the 5th process of the manufacturing method of an inkjet head. It is a perspective view explaining the 6th process of the manufacturing method of an inkjet head. It is a top view which shows 2nd Embodiment of the inkjet head of this invention. It is a perspective view which shows 3rd Embodiment of the inkjet head of this invention. It is a perspective view which shows 4th Embodiment of the inkjet head of this invention. It is a perspective view which shows 5th Embodiment of the inkjet head of this invention. 1 is a perspective view showing an embodiment of an inkjet head device of the present invention. It is a perspective view which shows the conventional inkjet head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 2 Nozzle plate 3 Main-body part 3a 1st member 3b 2nd member 4 Flexible cable 5a 1st flow path part 5b 2nd flow path part 6 Ink groove 6a Individual ink chamber 6b Dummy groove 7 Electrode 8 Nozzle hole 9 Electrode extraction Part 11 First common ink groove 11a First common ink chamber 11b Side surface 11c Bottom surface 12 Separation groove 13a First flow path port 13b Second flow path port 14 Filter 15 Bubble 16 Open end 20 Bulkhead 21 Second common ink groove 21a Second common ink Chamber 21b Side surface 21c Bottom surface 100, 200, 300, 400, 500, 600 Inkjet head 700 Inkjet head device S1 First plane S2 Second plane

Claims (27)

A piezoelectric substrate having a plurality of ink grooves extending in one direction and opening at both ends, and the plurality of ink grooves being arranged in parallel to each other in the other direction orthogonal to the one direction;
The piezoelectric substrate is attached, has a first common ink groove communicating with the plurality of ink grooves on one end side of the plurality of ink grooves, and communicates with the plurality of ink grooves on the other end side of the plurality of ink grooves. A main body having a second common ink groove;
The plurality of ink grooves, the first common ink groove and the second common ink groove are arranged so as to cover from above, and a plurality of individual ink chambers are defined together with the plurality of ink grooves, together with the first common ink groove A nozzle plate defining a first common ink chamber and defining a second common ink chamber together with the second common ink groove;
The main body has a first flow passage opening communicating with the first common ink chamber and a second flow passage opening communicating with the second common ink chamber, and the nozzle plate is located at a position corresponding to the ink groove. Has nozzle holes,
In the area where the first plane perpendicular to the other direction intersects the first common ink chamber, the area at the position where the first plane intersects the center of the first flow path port is the first plane is the other direction. An ink jet head characterized by being larger than an area at a position where the outermost ink groove intersects. The inkjet head according to claim 1,
In the area where the second plane perpendicular to the other direction and the second common ink chamber intersect, the area at the position where the second plane intersects the center of the second flow path port is the second plane is the other direction. An ink jet head characterized by being larger than an area at a position where the outermost ink groove intersects. The inkjet head according to claim 1 or 2,
An ink jet head, wherein at least a part of a side surface of the first common ink groove facing an end of the ink groove is formed in a concave curved surface. The inkjet head according to any one of claims 1 to 3,
An ink jet head, wherein at least a part of a side surface of the second common ink groove facing the end of the ink groove is formed in a concave curved surface. In the inkjet head according to any one of claims 1 to 4,
The inkjet head according to claim 1, wherein at least a part of a bottom surface of the first common ink groove facing the nozzle plate is formed in a concave curved surface. The inkjet head according to any one of claims 1 to 5,
The inkjet head according to claim 1, wherein at least a part of a bottom surface of the second common ink groove facing the nozzle plate is formed in a concave curved surface. The inkjet head according to any one of claims 1 to 6,
At least a part of the boundary surface between the side surface of the first common ink groove facing the end of the ink groove and the bottom surface of the first common ink groove facing the nozzle plate is formed as a concave curved surface. An ink jet head characterized by comprising: The inkjet head according to any one of claims 1 to 7,
At least a part of the boundary surface between the side surface of the second common ink groove facing the end of the ink groove and the bottom surface of the second common ink groove facing the nozzle plate is formed as a concave curved surface. An ink jet head characterized by comprising: The inkjet head according to claim 1,
In the width in the one direction of the first common ink groove on a plane parallel to the plane including the one direction and the other direction, the width at the position where the first plane intersects the center of the first flow path port is the width of the first common ink groove. An ink-jet head, wherein the first plane is larger than a width at a position where the first plane intersects the outermost ink groove in the other direction. The inkjet head according to claim 1 or 9,
In the depth of the first common ink groove on the plane orthogonal to the one direction, the depth at the position where the first plane intersects the center of the first flow path port is the maximum depth of the first plane in the other direction. An ink-jet head characterized by being larger than a depth at a position where the end ink groove intersects. The inkjet head according to claim 2,
In the width in the one direction of the second common ink groove on a plane parallel to the plane including the one direction and the other direction, the width at the position where the second plane intersects the center of the second flow path port is the above-described width. An inkjet head characterized in that the second plane is larger than a width at a position where the second plane intersects the outermost ink groove in the other direction. The inkjet head according to claim 2 or 11,
In the depth of the second common ink groove on the plane orthogonal to the one direction, the depth at the position where the second plane intersects the center of the second flow path port is the second plane is the maximum in the other direction. An ink-jet head characterized by being larger than a depth at a position where the end ink groove intersects. The inkjet head according to any one of claims 1 to 12,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
An ink jet head, wherein at least one of the first flow path portion and the second flow path portion is linear. The inkjet head according to any one of claims 1 to 13,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
The inkjet head according to claim 1, wherein an inner surface of a cross section in at least one of the first channel portion and the second channel portion has a curved surface. The inkjet head according to claim 14, wherein
The inkjet head according to claim 1, wherein an inner surface of a cross section in at least one of the first flow path portion and the second flow path portion is formed in a circular shape. In the ink jet head according to any one of claims 1 to 15,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
The inkjet head according to claim 1, wherein a cross-sectional area of each of the first flow path portion and the second flow path portion is larger than a cross-sectional area of each individual ink chamber. The inkjet head according to any one of claims 1 to 16,
The ink jet head according to claim 1, wherein the nozzle plate has no nozzle hole at a position corresponding to the outermost ink groove. The inkjet head according to any one of claims 1 to 17,
The main body is composed of a plurality of members. The inkjet head according to any one of claims 1 to 18,
The inkjet head according to claim 1, wherein the piezoelectric substrate is bonded and fixed to the main body through an elastic adhesive. The inkjet head according to any one of claims 1 to 17,
The inkjet head according to claim 1, wherein the piezoelectric substrate and the main body are formed of a single member that is integrally connected. The inkjet head according to any one of claims 1 to 20,
The main body has a first flow path part in which the first flow path port is an open end, and a second flow path part in which the second flow path port is an open end,
An ink jet head, wherein a filter is communicated with each of the first flow path portion and the second flow path portion. The inkjet head according to any one of claims 1 to 21,
Each of the first channel port and the second channel port is provided,
The first flow path port is located at a substantially center in the other direction in the first common ink groove,
The inkjet head according to claim 1, wherein the second flow path port is positioned at a substantially center in the other direction in the second common ink groove. The inkjet head according to claim 1 or 2,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The shortest distance between the bottom surface of the second common ink groove facing the nozzle plate and the nozzle plate is shorter than the shortest distance between the bottom surface of the ink groove facing the nozzle plate and the nozzle plate. An ink jet head characterized by being large. In the inkjet head according to claim 1, 2, or 23,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
Is the shortest distance between the bottom surface of the first common ink groove facing the nozzle plate and the nozzle plate equal to the shortest distance between the bottom surface of the ink groove facing the nozzle plate and the nozzle plate? An inkjet head characterized by being small. In the inkjet head according to claim 1, 2, 23 or 24,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The inkjet head according to claim 1, wherein the second flow path port is located on a bottom surface of the second common ink groove facing the nozzle plate. In the ink jet head according to claim 1, 2, 23, 24 or 25,
The first flow path port is an ink inflow port, the second flow path port is an ink outflow port,
The main body has a first flow path part in which the first flow path port is an open end,
An ink-jet head, wherein a filter is communicated with the first flow path portion.   An ink jet head device comprising the ink jet head according to any one of claims 1 to 26.

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