JP2012210775A - Liquid jetting head and liquid jetting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: when an end region of a reservoir is pointed, stress is concentrated on the pointed part and a crack (a fracture) is likely to occur from the pointed end.SOLUTION: A dummy flow channel part at the peripheral edge of a flow channel formation substrate has a shape where stress is likely to concentrate, and this portion is weaker than other portions. Consequently, when thermal stress is generated due to a temperature change in joining a flow channel unit component, a crack can be generated in the weak portion in preference to the other portions, starting from a stress concentration region. In particular, although a similar corner part is formed at a flow channel part, a position facing the peripheral edge side and adjacent to the stress concentration region is formed with a thin wall part thinned in wall thickness also on the flow channel formation substrate side. Since the wall thickness of this portion is thin while having a shape where stress is likely to occur, the crack is more likely to occur.

Description

  The present invention relates to a liquid ejecting head having a series of liquid flow paths from a common liquid chamber formed in a flow path forming substrate to a nozzle opening through a pressure chamber, and a liquid ejecting apparatus including the liquid ejecting head.

  Examples of the liquid ejecting head that ejects liquid droplets from the nozzle openings by causing pressure fluctuations in the pressure chamber include, for example, an ink jet recording head (hereinafter simply referred to as an ink jet recording head) used in an image recording apparatus (liquid ejecting apparatus) such as a printer. Recording head), color material ejecting head used for manufacturing color filters such as liquid crystal displays, electrode material ejecting heads used for forming electrodes such as organic EL (Electro Luminescence) displays, FED (surface emitting displays), biochips ( There are bioorganic ejecting heads and the like used in the manufacture of biochemical elements.

  Taking the case of the above recording head as an example, this recording head includes a nozzle plate having a plurality of nozzle openings, and an empty portion that defines a series of ink flow paths from a common ink chamber to a nozzle opening through a pressure chamber. A flow path forming substrate having a flow path portion such as a groove or a groove, an elastic plate in which a region corresponding to a pressure chamber is elastically deformed according to the operation of a pressure generating element (sealing for sealing an opening surface of the flow path forming substrate) It is comprised including the flow path unit which can also be said to be a board (for example, refer patent document 1). Among these flow path unit constituent members, the flow path forming substrate is required to have a high processing density and processing accuracy in order to cope with a high density of recorded images and a high speed recording operation. Therefore, a silicon single crystal substrate (silicon wafer) that can form a fine shape with high dimensional accuracy by anisotropic etching or the like is preferably used as the material of the flow path forming substrate. On the other hand, as a material for the nozzle plate and the elastic plate, for example, a metal plate material such as a stainless steel is used for ease of processing.

  As described above, the flow path forming substrate is provided with a flow path portion such as a through hole (hereinafter simply referred to as a reservoir) serving as a common ink chamber by anisotropic etching or the like. In the head, the end region of the reservoir is formed in a sharp shape that is gradually narrowed toward the end. This is because the ink flow can be made smooth in the end region of the reservoir, and bubbles can be prevented from staying in this region.

Japanese Patent Laid-Open No. 2000-177119 (FIGS. 4, 10, etc.)

  The constituent members of the flow path unit including the nozzle plate, the flow path forming substrate, and the elastic plate are joined by interposing an adhesive between the constituent members and heating and curing the adhesive. However, when the flow path forming substrate is made of silicon and the nozzle plate is made of a metal plate such as stainless steel, there is a difference in linear expansion coefficient between the base materials of these components, Due to temperature changes caused by heating and cooling during joining, a relative expansion / contraction difference may occur, and the constituent members may be deformed. At this time, the peripheral edge side of the flow path forming substrate is higher in rigidity than the central side where the flow path portion is provided, and stress concentrates on the boundary portion between the high rigidity area and the low rigidity area. Cracks may occur in the formation substrate. In particular, as in the example of Patent Document 1, when the end region of the reservoir has a sharp shape, since the point is sharp, stress concentrates on the sharp portion. ) Is likely to occur.

When a crack occurs in a flow path such as a reservoir in this way, ink leaks to the outside of the recording head through the crack, or ink leaked through the crack enters a flow path corresponding to another color and mixes colors. Can occur.
The present invention has been made in view of such circumstances, and the purpose thereof is a liquid ejecting head capable of preventing cracks in the liquid flow path of the flow path forming substrate as much as possible. An object of the present invention is to provide a liquid ejecting apparatus including the liquid ejecting head.

According to the present invention, a common liquid chamber that supplies a liquid to a pressure chamber that receives pressure fluctuations in an internal liquid by a pressure generating element, a flow path forming substrate having a flow path portion, and a nozzle opening that communicates with the pressure chamber are formed. A liquid ejecting head that ejects liquid from the nozzle opening in response to the operation of the pressure generating element, wherein the flow path forming substrate is used for discharging droplets. Is not involved and has a dummy flow path portion made of a space penetrating the flow path forming substrate, and the flow path forming substrate is formed from the peripheral side of the dummy flow path portion to the peripheral portion of the flow path forming substrate. A thin portion with a reduced thickness is formed in a region toward the side.
Further, the flow path forming substrate may have a stress concentration region formed in a shape in which stress is easily concentrated in a region on the peripheral edge side of the dummy flow channel portion.

  According to the above configuration, at the periphery of the flow path forming substrate, a shape in which stress tends to concentrate on the dummy flow path portion is formed and becomes weaker than other portions. When a thermal stress is generated due to the temperature change, cracks can be induced in a weak part preferentially over other parts with the stress concentration region as a base point. In particular, although the same corner portion is formed in the flow path portion, the position toward the peripheral edge side on the flow path forming substrate side adjacent to the stress concentration region is a thin portion with a reduced thickness. Forming. That is, since the thickness of the part is thin on the shape where stress is likely to concentrate, it becomes easier to induce cracks.

Further, the flow path forming substrate may be formed of a base material having crystallinity, and the thin portion may be formed along the direction of the closest packed surface in the crystal structure from the stress concentration region.
Generally, when it has a crystal structure, it tends to break along the direction of the closest packed surface. Therefore, if the thin-walled portion is formed along the direction of the close-packed surface from the stress concentration region, the thin-walled portion easily breaks along that direction.
Further, the dummy channel portion has a shape in which stress is likely to concentrate, and a corner portion where two surfaces intersect is formed at a portion near the peripheral portion of the channel forming substrate, and the thin portion is in contact with the corner portion. Can be formed.

Since stress tends to concentrate at the corner where the two surfaces intersect, the effect of the thin portion is also synergistic, and cracks are more likely to be induced.
The contact with the corners means that when the thin part is formed with a certain width, somewhere from the end to the end is in contact with the corner. It may be in the middle of the thin portion or at the end.
Then, one of the two surfaces forming the corners of the dummy channel portion may be the closest surface in the crystal structure.

The close-packed surface in the crystal structure is more susceptible to cracking than other angles. That is, when stress concentrates, it is easy to break along this close-packed surface. Since the one surface forming the corner is the close-packed surface, cracks can be induced in the corner more reliably.
The thin portion may be formed so as to be connected from the stress concentration region of the dummy flow path portion to the periphery of the flow path forming substrate.

Since the thin-walled portion is connected from the stress concentration region to the peripheral edge, it is difficult to induce a crack in a portion other than the thin-walled portion.
Further, the thin portion may be formed so as not to be connected from the stress concentration region of the dummy flow path portion to the periphery of the flow path forming substrate.
Although it is excellent in that cracks are not induced in other portions when connected to the periphery, the strength of the entire flow path forming substrate tends to decrease. For this reason, since the thin-walled portion only has to act in terms of inducing cracks, it is not necessarily connected to the periphery, and instead, the strength of the entire flow path forming substrate can be ensured.

Further, a plurality of stress concentration regions of the dummy flow path portion may be formed, and the thin portion may be formed adjacent to the plurality of stress concentration regions.
Although the stress concentration region is not limited to one, since the thin portion has a shape having a certain width, it may be formed so as to be adjacent to a plurality of stress concentration regions.
Of course, a liquid ejecting apparatus including such a liquid ejecting head can similarly induce cracks.
As a more specific configuration of the liquid ejecting head, a flow path forming substrate in which a flow path portion including a predetermined liquid flow path for each nozzle opening and a common liquid chamber common to each color is formed, and a droplet The nozzle opening from which the nozzle is discharged is opened, and the nozzle forming member bonded to one surface of the flow path forming substrate and the other surface of the flow path forming substrate are bonded to each other according to the operation of the pressure generating element. A region corresponding to a pressure chamber, which is a predetermined liquid flow path for each nozzle opening, is composed of an elastic plate that elastically deforms, and a series of liquid flow paths from the common liquid chamber through the pressure chamber to the nozzle opening You may make it provide the flow path unit which forms.
In addition, the flow path forming substrate has a dummy flow path portion that is not involved in the discharge of liquid droplets and includes a space penetrating the flow path forming substrate together with the flow path portion. Is formed as a shape having a stress concentration region where stress is likely to concentrate at a portion close to the peripheral portion of the flow path forming substrate, and the flow path forming substrate is positioned adjacent to the stress concentration region and toward the peripheral portion side. It is possible to form a thin part with a reduced thickness.

  According to the present invention, it is possible to disperse the thermal stress at the time of bonding to the dummy flow path portion that is not filled with ink or the like, and it is possible to suppress the generation of cracks on the flow path portion side. As a result, it is possible to prevent problems such as the liquid leaking outside the liquid ejecting head or the liquid entering the other flow path portion and mixing the liquid.

FIG. 2 is an exploded perspective view illustrating a configuration of a recording head. FIG. 3 is a cross-sectional view of a main part for explaining the configuration of a recording head. It is a top view of the silicon wafer used as the base material of a flow-path formation board | substrate. It is a top view explaining the structure of a flow-path formation board | substrate. It is an enlarged view of the area | region A in FIG. It is sectional drawing which shows a thin part. It is a figure which shows the modification of a thin part. It is a figure which shows the modification of a thin part.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following description, an ink jet recording head (hereinafter simply referred to as a recording head) mounted on an ink jet recording apparatus (a type of liquid ejecting apparatus; hereinafter simply referred to as a printer) is taken as an example of the liquid ejecting head of the present invention. To do.

  FIG. 1 is an exploded perspective view of the recording head 1 in the present embodiment, and FIG. The illustrated recording head 1 includes a cartridge base 2 (hereinafter referred to as “base”), a drive substrate 5, a case 10, a flow path unit 11, and an actuator unit 13 as main components. The base 2 is molded from, for example, a synthetic resin such as an epoxy resin, and a plurality of ink introduction needles 4 are attached to the upper surface of the base 2 with a filter 3 interposed therebetween. These ink introduction needles 4 are mounted with ink cartridges (not shown) that store ink (a kind of liquid).

  The drive substrate 5 is provided with a wiring pattern for supplying a drive signal from the printer main body (not shown) to the piezoelectric vibrator 19 and a connector 6 for connection with the printer main body, a resistor, a capacitor, etc. The electronic parts 8 and the like are mounted. A wiring member such as an FFC (flexible flat cable) is connected to the connector 6, and the driving substrate 5 receives a driving signal from the printer main body side via the FFC. The driving substrate 5 is disposed on the bottom surface side of the base 2 opposite to the ink introduction needle 4 with a sheet 7 functioning as a packing interposed.

  The case 10 is a hollow box-shaped member made of synthetic resin, the flow path unit 11 is joined to the front end surface (lower surface), the actuator unit 13 is accommodated in the accommodation space 12 formed inside, The drive substrate 5 is attached to the substrate attachment surface 14 on the side opposite to the flow path unit 11 side. A head cover 16 made of a metal thin plate member is attached to the front end surface side of the case 10 so as to surround the peripheral edge portion from the outside of the flow path unit 11. The head cover 16 functions to protect the flow path unit 11 and the case 10 and adjust the nozzle plate 25 of the flow path unit 11 to the ground potential to prevent troubles such as noise caused by static electricity generated from recording paper or the like. .

  The actuator unit 13 includes a plurality of piezoelectric vibrators 19 (a kind of pressure generating elements) arranged in a comb shape, a fixed plate 20 to which the piezoelectric vibrators 19 are joined, and driving from the driving substrate 5. A wiring member 21 such as a TCP (tape carrier package) for transmitting a signal to the piezoelectric vibrator 19 is formed. Each piezoelectric vibrator 19 has a fixed end portion bonded to the fixed plate 20, and a free end portion protruding outward from the front end surface of the fixed plate 20. That is, each piezoelectric vibrator 19 is mounted on the fixed plate 20 in a so-called cantilever state. The fixing plate 20 that supports each piezoelectric vibrator 19 is made of, for example, stainless steel having a thickness of about 1 mm. The actuator unit 13 is housed and fixed in the housing space 12 by bonding the back surface of the fixed plate 20 to the inner wall surface of the case that defines the housing space 12.

  The flow path unit 11 is manufactured by joining and integrating a flow path unit constituent member made up of an elastic plate 23, a flow path forming substrate 24, and a nozzle plate 25 with an adhesive in a common ink. It is a member that forms a series of ink flow paths (corresponding to the liquid flow paths in the present invention) from the chamber 27 (common liquid chamber) through the ink supply port 28 and the pressure chamber 29 to the nozzle opening 30. The pressure chamber 29 is formed as an elongated chamber in a direction orthogonal to the direction in which the nozzle openings 30 are arranged (nozzle row direction). The common ink chamber 27 is a chamber into which ink from the side of the ink introduction needle 4 inserted into the ink cartridge is introduced. The ink introduced into the common ink chamber 27 is distributed and supplied to each pressure chamber 29 through the ink supply port 28.

  A nozzle plate 25 (a kind of nozzle forming member in the present invention) disposed at the bottom of the flow path unit 11 allows a plurality of nozzle openings 30 to be moved in the paper feed direction (sub-scanning) at a pitch (for example, 180 dpi) corresponding to the dot formation density. It is a thin plate made of metal opened in a row in the direction). The nozzle plate 25 of the present embodiment is made of a stainless steel plate material, and a plurality of rows of nozzle openings 30 (nozzle rows) are arranged in the scanning direction (main scanning direction) of the recording head 1. One nozzle row is composed of, for example, 180 nozzle openings 30. The recording head 1 of the present embodiment is configured to be able to eject a total of four colors of cyan (C), magenta (M), yellow (Y), and black (K), and corresponds to these colors. A total of four nozzle rows are formed on the nozzle plate 25.

  A flow path forming substrate 24 that is one of the flow path unit constituent members is a flow path section 40 that becomes an ink flow path, specifically, an opening 41 that becomes a common ink chamber 27, a groove that becomes an ink supply port 28, And it is the plate-shaped member in which the empty part 42 (all refer FIG. 4) used as the pressure chamber 29 was dividedly formed. In this embodiment, the flow path forming substrate 24 is produced by subjecting a silicon wafer, which is a crystalline base material, to anisotropic etching. Details of the flow path forming substrate 24 will be described later with reference to FIG.

  The elastic plate 23 disposed on the surface of the flow path forming substrate 24 opposite to the nozzle plate 25 is a double-structure composite plate material obtained by laminating an elastic film on a metal support plate such as stainless steel. An island portion 32 for joining the tip of the free end of the piezoelectric vibrator 19 is formed in a portion corresponding to the pressure chamber 29 of the elastic plate 23, and this portion functions as a diaphragm portion. That is, the elastic plate 23 is configured such that the elastic film around the island portion 32 is elastically deformed in accordance with the operation of the piezoelectric vibrator 19. In addition, the elastic plate 23 seals one opening surface of the opening 41 of the flow path forming substrate 24 and also functions as a compliance portion 33. A portion corresponding to the compliance portion 33 is made of only an elastic film.

The elastic plate 23 can also be referred to as a sealing plate that seals the opening surface of the flow path portion 40 formed on the flow path forming substrate 24.
In the recording head 1, when a driving signal is supplied from the driving substrate 5 to the piezoelectric vibrator 19 through the wiring member 21, the piezoelectric vibrator 19 expands and contracts in the longitudinal direction of the element, and accordingly, the island portion 32. Moves in a direction close to or away from the pressure chamber 29. As a result, the volume of the pressure chamber 29 changes, and the pressure in the ink in the pressure chamber 29 changes. An ink droplet (a kind of droplet) is ejected from the nozzle opening 30 by this pressure fluctuation. That is, the piezoelectric vibrator 19 can be said to be a kind of pressure generating source that can cause ink in the pressure chamber 29 to be ejected from the nozzle opening 30 as ink droplets by generating pressure fluctuations in the ink in the pressure chamber 29. .

  FIG. 3 is a plan view of a silicon wafer 35 that is a material of the flow path forming substrate 24. The silicon wafer 35 is, for example, a silicon single crystal substrate whose surface 37 is set to a crystal orientation plane (110) plane. On the surface 37 of the silicon wafer 35, a plurality of substrate regions 24 ′ to be the flow path forming substrate 24 are divided by the planned cutting lines L1 and L2 (10 in this embodiment), and each substrate region 24 ′. The channel portion 40 (see FIG. 4) serving as the ink channel is formed by anisotropic etching. On the planned cutting lines L1 and L2, a plurality of elongated and small through holes are similarly formed by anisotropic etching to form a break pattern. 3 is set on the (110) plane and in the plane direction of the first (111) plane orthogonal to the (110) plane. In addition, a vertical longitudinal cutting line L2 perpendicular to the horizontal cutting line L1 is set in the axial direction perpendicular to the first (111) plane. The first (111) plane constitutes an orientation flat (so-called orientation flat) OF which becomes a reference plane in anisotropic etching.

  FIG. 4 is a plan view illustrating the configuration of the flow path forming substrate 24 obtained by dividing the silicon wafer 35 along the planned cutting lines L1 and L2. As shown in the figure, a flow path portion 40 including an opening 41, an empty portion 42, and the like is formed in the central portion 24a of the flow path forming substrate 24 by anisotropic etching. In the present embodiment, a total of four rows of openings 41 serving as the common ink chambers 27 are formed corresponding to the four colors of ink. From each opening 41, a groove (not shown) serving as the ink supply port 28 and a hollow 42 serving as the pressure chamber 29 are branched into a plurality corresponding to the nozzle openings 30 formed in the nozzle plate 25. Is formed. In the flow path forming substrate 24 of the present embodiment, a total of four sets of flow path portions 40 each including a row of openings 41 and empty portions 42 are formed in a state of being arranged in the main scanning direction. In FIG. 4, the two sets of flow path portions 40 on the left side and the two sets of flow path portions 40 on the right side are paired, and the rows of the empty portions 42 (pressure chamber rows) face each other. Has been placed.

  In addition, a dummy flow path portion 44 that is a through hole that is not involved in the ejection of ink droplets is provided in parallel on the flow path forming substrate 24 in a state of being separated from the flow path portion 40. In the present embodiment, two dummy flow path portions 44 are provided between the pair of flow path portions 40, one in total. More specifically, the dummy flow path portion 44 is disposed between the rows of the empty portions 42 in the adjacent flow path portions 40. Since the dummy flow path portion 44 is provided apart from the flow path portion 40 (that is, in a state not communicating with the flow path portion 40), the dummy flow path portion 44 is normally a portion into which ink does not enter. By adjusting the rigidity of a part of the formation substrate 24, specifically, by intentionally reducing the rigidity between the rows of the empty portions 42, the stress concentration between the rows of the empty portions 42 when the piezoelectric vibrator 19 is driven. It is a part that functions as a buffer hole for relaxing the above. The dummy flow path portion 44 also functions as an escape hole for introducing excess adhesive or bubbles when the flow path unit constituent members are joined, and the adhesive flows into the flow path section 40 side, It prevents the occurrence of poor adhesion due to bubbles entering between the members.

  By the way, both end portions in the sub-scanning direction of the opening 41 are gradually narrowed and pointed toward the end. In this way, the flow of ink at both ends of the opening 41, that is, at both ends of the common ink chamber 27 can be made smooth, and bubbles can be prevented from staying in this portion. However, since the point is sharp, stress concentrates at both ends of the opening 41, so that a crack is easily generated from the tip. If a crack occurs in the flow path section 40 such as the opening 41, ink leaks to the outside of the head through the crack, or the ink leaked through the crack enters the flow path section 40 corresponding to another color. There is a risk of color mixing. In order to solve such a problem, in the flow path forming substrate 24, the shape of the dummy flow path portion 44 is devised, thereby solving the above problem. Hereinafter, this point will be described.

FIG. 5 is an enlarged view of region A in FIG. The dummy flow path portions 44 in the flow path forming substrate 24 are directed to the outside of the flow path forming substrate 24 at both ends in a direction (sub-scanning direction in the present embodiment) perpendicular to the parallel arrangement direction with the flow path portion 40. It has a tapered corner 44a. In such a corner shape where two surfaces intersect, stress is likely to concentrate. Therefore, the corner portion can be said to be a stress concentration position, and this region can be said to be a stress concentration region. On the other hand, a thin-walled portion 46 is formed on the flow path forming substrate 24 so as to contact the corner portion 44a.
6 is a cross-sectional view taken along line BB in FIG.
As shown in FIG. 6, the thin portion 46 is a portion dug down a predetermined distance from the upper surface of the flow path forming substrate 24. In other words, it can be said that a groove having a U-shaped cross-section is formed above the lower portion because the thickness is reduced. Such a shape of the thin portion 46 can be formed by half etching. It can be formed at the same time in the process of forming the voids 42 and the like.

  As a result of the formation of the thin portion 46 adjacent to the corner portion 44a where stress tends to concentrate, in the peripheral portion 24b, the corner portion 44a is less rigid and weak, and the thickness is reduced. Cracks are more likely to occur than the tip of the flow path portion 44. Further, the thin portion 46 has a shape connected to the peripheral portion of the flow path forming substrate 24 while being adjacent to the corner portion 44 a on the side close to the dummy flow path portion 44. Next, this direction will be described.

  Here, the base material having crystallinity such as the silicon wafer 35 which is the base material of the flow path forming substrate 24 of the present embodiment has a crystal orientation plane in which crystals are closest when an external force or impact is applied, That is, it tends to break along the closest surface. This close-packed surface varies depending on the crystal structure of the base material. For example, in the case of a face-centered cubic structure (FCC) like the silicon wafer 35 in the present embodiment, the (111) plane, the body-centered cubic structure (BCC) In the case of (1), the (110) plane is the closest packed plane. That is, the direction of the close-packed surface functions as a crack guiding surface that actively induces cracks. In FIG. 5, this close-packed surface is indicated by a broken line, and the thin portion 45 is formed toward the close-packed surface. Therefore, when a crack occurs in the thin wall portion 46, the crack proceeds along the close-packed surface. However, since the thin-wall portion 46 is formed toward the close-packed surface, the crack is surely along the thin-walled portion 46. Will go on.

FIG. 7 shows a modification of the thin portion, but the shape of the corner portion 44b itself is also changed.
In this example, the corner portion 44b extends one surface 44b1 extending in the longitudinal direction of the dummy channel portion 44 as it is, forms a surface 44b2 along the closest surface from the vicinity of the tip of the other surface 44b3, and the surface 44b2 and the surface 44b1 intersects to form a corner 44b. The thin portion 47 has a predetermined width, but is formed so that the end thereof is connected to the surface 44b2 which is the closest packed surface.

  That is, in this embodiment, at least one surface 44b2 of the surfaces 44b1 and 44b2 that define the corner 44a is set as the closest surface of the flow path forming substrate 24 (silicon wafer 35). Specifically, one surface 44b2 of the corner 44b is set as a second (111) surface that intersects the first (111) surface as an orientation flat at about 70 ° on the (110) surface. . That is, the surface 44b2 functions as a crack induction surface that actively induces cracks. In this way, by making at least one of the surfaces defining the cut portion 44 as a closest-packed surface (crack induction surface), it is easier to induce a crack along the crack induction surface with the tip of the cut portion 44 as a base point. Can do. Furthermore, by forming at least one surface 44b2 of the surfaces 44b1 and 44b2 partitioning the corner portion 44b as a close-packed surface (crack induction surface) and forming a thin portion 47 in contact therewith, cracks are formed along the crack induction surface. Can be more easily induced.

  In addition, both the dummy channel portion 44 and the channel portion 40 are basically formed in the shape of a long hole along the sub-scanning direction, and the dummy channel portion 44 is longer than the channel portion 40. For this reason, the corners 44 a and 44 b of the dummy channel part 44 are located closer to the peripheral part of the channel forming substrate 24 than the tip of the channel part 40. Due to this positional relationship between the two, it can be said that the stress is more likely to be concentrated on the corner 44a side. Furthermore, when one dummy flow path portion 44 is sandwiched between the two flow path portions 40, one dummy flow path portion 44 induces cracks prior to the two flow path portions 40, and the dummy The number of flow path portions 44 can be reduced. If the crack is induced, the overall rigidity is lowered, so that the smaller the number, the higher the overall rigidity can be maintained.

FIG. 8 shows a modification of the thin wall portion and the dummy channel portion.
In this example, two corner portions 44 c and 44 d are formed at the tip of the dummy flow path portion 44. The surfaces forming the corner portions 44c and 44d are the same as the two surfaces 44b1 and 44b2 shown in FIG. And the thin part 48 is formed so that these two corner | angular parts 44c and 44d may be contact | connected. Since the two corners 44c and 44d are adjacent to the thin portion 48 and there are two, the dummy channel portion 44 is more likely to induce cracks. In this example, the thin portion 48 does not reach the periphery of the flow path forming substrate 24. Thereby, the strength of the entire flow path forming substrate 24 can be prevented from being lowered by the thin portion 48.

  As described above, the corner portion where the dummy flow path portion 44 in the flow path formation substrate 24 is tapered toward the outside of the flow path formation substrate 24 at the end portion in the direction orthogonal to the direction in which the flow path portion 40 is juxtaposed. 44a to 44d and thin wall portions 46 to 48 are formed adjacent to the corner portions 44a to 44d, so that the corner portions 44a to 44d of the dummy flow passage portion 44 flow at the peripheral edge portion 24b. Since stress is more easily concentrated than the tip of the path portion 40 and becomes fragile, when thermal stress is generated due to a temperature change at the time of joining the flow path unit constituent members, the thin-walled portion 46 to the tip of the corner portions 44a to 44d are used as base points. It is possible to induce a crack in a portion that is preferentially weaker than other portions along the line 48. For this reason, the thermal stress at the time of joining can be disperse | distributed and it becomes possible to suppress as much as possible that a crack arises in the flow-path part 40 side. As a result, it is possible to prevent problems such as ink leaking to the outside of the recording head 1 or color mixing due to ink entering the other flow path section 40 from the flow path section 40.

By the way, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the description of the scope of claims.
In the above, an example in which the flow path forming substrate 24 is manufactured using the silicon wafer 35 has been shown. However, the base material of the flow path forming substrate 24 is not limited to the silicon wafer 35 and other base materials having crystallinity. It is also possible to use. Moreover, even if it is a base material which does not have crystallinity, it will not change that it becomes easy to induce a crack by a thin part.

In addition, with respect to the flow path forming substrate 24, the above embodiment has been described with an example in which the flow path forming substrate 24 is configured by a single plate material. However, the present invention is not limited thereto, and the flow path forming substrate 24 may be configured by a plurality of plate materials. That is, for example, a first flow path forming substrate in which a groove portion serving as the ink supply port 28 and a void portion 42 serving as the pressure chamber 29 are formed, and a second flow path formation including an opening portion 41 serving as the common ink chamber 27 are formed. It is also possible to configure the flow path forming substrate 24 with two substrates. In this case, a dummy channel portion 44 is formed on each substrate, and a thin portion is formed adjacent to a corner portion of the dummy channel portion 44.

  In the above description, the ink jet recording head 1 has been described as an example of the liquid ejecting head, but the present invention can also be applied to other liquid ejecting heads. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, an FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Applying mutually interchangeable members and configurations disclosed in the above embodiments by appropriately changing the combination thereof.− Although not disclosed in the above embodiments, it is a publicly known technique and the above embodiments. The members and configurations that can be mutually replaced with the members and configurations disclosed in the above are appropriately replaced, and the combination is changed and applied.

・ Although not disclosed in the above-described embodiments, those skilled in the art may appropriately substitute members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above-described embodiments based on known techniques, Changing and applying the combination is disclosed as an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Cartridge base, 3 ... Filter, 4 ... Ink introduction needle, 5 ... Drive board, 6 ... Connector, 7 ... Sheet, 8 ... Electronic component, 10 ... Case, 11 ... Flow path unit, DESCRIPTION OF SYMBOLS 12 ... Accommodating empty part, 13 ... Actuator unit, 14 ... Board | substrate attachment surface, 16 ... Head cover, 19 ... Piezoelectric vibrator, 20 ... Fixed plate, 21 ... Wiring member, 23 ... Elastic board, 24 ... Flow path formation board | substrate, 25 ... Nozzle plate, 27 ... Common ink chamber, 28 ... Ink supply port, 29 ... Pressure chamber, 30 ... Nozzle opening, 32 ... Island part, 35 ... Silicon wafer, 37 ... Surface of silicon wafer, 40 ... Channel part, 41 ... Opening, 42... Empty, 44.

Claims (9)

A common liquid chamber that supplies liquid to a pressure chamber that receives pressure fluctuations in the internal liquid by the pressure generating element, and a flow path forming substrate in which a flow path section is formed
A liquid ejecting head that includes a flow path unit having a nozzle forming member in which a nozzle opening communicating with the pressure chamber is formed, and ejects liquid from the nozzle opening according to the operation of the pressure generating element,
The flow path forming substrate has a dummy flow path portion that is not involved in the discharge of liquid droplets and includes a space penetrating the flow path forming substrate.
The flow path forming substrate is characterized in that a thin portion having a reduced thickness is formed in a region from the peripheral edge side of the dummy flow path portion toward the peripheral edge side of the flow path forming substrate. Jet head.   The liquid jet head according to claim 1, wherein the flow path forming substrate has a stress concentration region formed in a shape in which stress is easily concentrated in a region on a peripheral edge side of the dummy flow path portion.   The said flow path formation board | substrate is formed with the base material which has crystallinity, and the said thin part is formed along the direction of the close-packed surface in a crystal structure from the said stress concentration area | region. Alternatively, the liquid ejecting head according to claim 2. The dummy channel portion is formed with a corner where two surfaces intersect at a portion near the peripheral edge of the channel forming substrate as a shape in which stress is easily concentrated,
The liquid ejecting head according to claim 1, wherein the thin portion includes the corner portion.   5. The liquid jet head according to claim 4, wherein one of two surfaces forming a corner portion of the dummy flow path portion is a closest surface in a crystal structure.   The liquid jet head according to claim 1, wherein the thin portion is connected from a stress concentration region of the dummy flow path portion to a peripheral edge of the flow path forming substrate.   The liquid jet head according to claim 1, wherein the thin portion is not connected from a stress concentration region of the dummy flow path portion to a peripheral edge of the flow path forming substrate.   The liquid ejecting head according to claim 1, wherein a plurality of stress concentration regions of the dummy flow path portion are formed, and the thin portion is adjacent to the plurality of stress concentration regions. . A common liquid chamber that supplies liquid to a pressure chamber that receives pressure fluctuations in the internal liquid by the pressure generating element, and a flow path forming substrate in which a flow path section is formed
A liquid ejecting apparatus including a flow path unit having a nozzle forming member formed with a nozzle opening communicating with the pressure chamber, and having a liquid ejecting head that ejects liquid from the nozzle opening in accordance with the operation of the pressure generating element. There,
The flow path forming substrate has a dummy flow path portion that is not involved in the discharge of liquid droplets and includes a space penetrating the flow path forming substrate.
The flow path forming substrate is characterized in that a thin portion having a reduced thickness is formed in a region from the peripheral edge side of the dummy flow path portion toward the peripheral edge side of the flow path forming substrate. Injection device.

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