JP2019147378A - Passage member - Google Patents

Abstract

To provide a passage member which is used in a liquid discharge device capable of discharging a liquid such as an ink from a discharge port and has relatively low passage resistance.SOLUTION: A passage member includes: a substrate 3 including a passage 2 having an opening 1; and a lid body 4 which is joined to the substrate so as to close the opening. The lid body includes a through hole 5 for discharging a liquid that passes through the opening to the outside. The lid body has a first facing surface 6 facing the passage. The substrate has a second facing surface 7 facing the passage and opposing the first facing surface. Center line average roughness Ra of the first facing surface is smaller than center line average roughness Ra of the second facing surface.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a flow path member used in a liquid ejection apparatus that can eject a liquid such as ink from an ejection port.

  Conventionally, a circulation type liquid ejection device such as an ink jet recording apparatus that circulates ink between a liquid container and a liquid ejection head has been used. As an example of a circulation type liquid ejection device, a line type (page wide type) liquid ejection in which a plurality of recording element substrates (hereinafter, the recording element substrates are simply referred to as element substrates) are arranged in the width direction of the printing paper. There is a device equipped with a head.

  As shown in FIG. 5, as a liquid discharge head (entire) mounted on this apparatus, as shown in FIG. 5, a liquid discharge head 101 that discharges liquid and a liquid discharge head that is provided corresponding to the discharge port 101 are provided. An element substrate 201 including an element (not shown) that generates energy for discharging the element, a pressure chamber 102 including the element inside, and a liquid supplied from a supply opening on the back side of the element substrate 201 A liquid discharge head is described that includes a supply path 51 that supplies the pressure chamber 102 and a first flow path member 205 that has a recovery path (not shown) for recovering the liquid recovered from the pressure chamber 102 to a recovery opening. ing.

  In this liquid discharge head, the element substrate 201 is supported by the support member 203, and the liquid communication port 31 of the support member 203 is opened toward the discharge port 101 provided in the element substrate 201.

  A second flow path member 206 is connected to the back surface of the first flow path member 205. In the second flow path member 206, a set of a common supply flow path 221 and a common recovery flow path 222 extending in the longitudinal direction of the liquid discharge head are provided. The communication port 61 of the second flow channel member 206 is connected to the individual communication port 53 of the first flow channel member 205, and the first flow from the common supply flow channel 221 of the second flow channel member 206 through the communication port 61. It communicates with the supply path 51 of the path member 205 so that the liquid is supplied.

  Although not shown in FIG. 5, in another cross section perpendicular to the longitudinal direction of the liquid discharge head, it communicates with the recovery path of the first flow path member 205 via the communication port 62 of the common recovery flow path 222. The liquid is collected.

JP 2017-124615 A

  Nowadays, the discharge ports 101 of the element substrate 201 are arranged at high density, and the flow channel resistance generated in the common supply flow channel 221 of the second flow channel member 206 is the flow channel resistance (pressure loss) of the liquid discharged from the discharge port 101. Has a relatively large impact. For this reason, it is required that the flow path resistance generated in the common supply flow path 221 be relatively low. The present disclosure provides a flow path member having a relatively low flow path resistance generated in a common supply flow path.

The flow path member of the present disclosure includes a base body including a flow path having an opening, and a lid body that is bonded to the base body so as to close the opening, and the lid body externally passes the liquid passing through the opening. A through hole for discharging, the lid body having a first facing surface facing the flow path, the base body having a second facing surface facing the flow path and facing the first facing surface; The center line average roughness Ra of the first facing surface is smaller than the center line average roughness Ra of the second facing surface.

  According to the present disclosure, a flow path member having a relatively low flow path resistance can be provided.

(A) which shows an example of the channel member of this indication, (b) is a sectional view in the XX 'line, (c) is an example which expanded A part, (d) is another which expanded A part It is an enlarged view which shows an example, respectively. It is sectional drawing which shows the other example of the flow-path member of this indication. It is sectional drawing which shows the other example of the flow-path member of this indication. (A) which shows the other example of the flow-path member of this indication is sectional drawing, (b) is an example which expanded the B part, (c) is an enlarged view which shows the other example which expanded the B part, respectively. It is sectional drawing which shows an example of the conventional flow-path member.

  Hereinafter, the flow path member of the present disclosure will be described in detail with reference to the drawings.

  1A is a perspective view, FIG. 1B is a cross-sectional view taken along the line XX ′, FIG. 1C is an enlarged view of an A portion, and FIG. 1D is an enlarged view of the A portion. It is an enlarged view which shows each other example expanded.

  A flow path member 30 shown in FIG. 1 includes a base body 3 including a flow path 2 having an opening 1 and a lid body 4 joined to the base body 3 so as to close the opening 1. A through-hole 5 for discharging the passing liquid L to the outside is provided, the lid 4 has a first facing surface 6 facing the flow channel 2, and the base body 3 faces the flow channel 2 and faces the first facing surface 6. The second opposing surface 7 is provided. A plurality of through-holes 5 are arranged at predetermined intervals along the longitudinal direction of the flow path 2 (the direction from the front to the back of the paper), and the cross-sectional shape thereof is circular. The liquid L is, for example, ink. When the liquid L is supplied to the flow path 2 from the outside, the liquid L flows along the flow path 2, and the liquid L having a predetermined flow rate passes through the opening 1 and penetrates the cover body 4. The liquid is discharged from the hole 5 to the outside.

  The base 3 and the lid 4 are each made of a ceramic mainly composed of aluminum oxide, aluminum nitride, or silicon carbide.

  The main component in the present disclosure refers to a component of 90% by mass or more out of a total of 100% by mass of components constituting the ceramic. In the case where the base 3 and the lid 4 are made of ceramics mainly composed of aluminum oxide, at least one of magnesium, silicon, and calcium may be included as an oxide.

  Here, the components constituting the ceramics can be identified by an X-ray diffractometer using CuKα rays, and the content of each component is, for example, an ICP (Inductively Coupled Plasma) emission spectroscopic analyzer or a fluorescent X-ray analyzer. It can ask for.

  In the flow path member 30 shown in FIG. 1, the center line average roughness Ra of the first facing surface 6 is smaller than the center line average roughness Ra of the second facing surface 7.

  With such a configuration, the flow path resistance of the liquid L flowing along the vicinity of the first facing surface 6 can be made lower than the flow resistance of the liquid L flowing along the vicinity of the second facing surface 7, so The discharge efficiency of the liquid L toward the hole 5 can be increased.

  Here, when the center line average roughness Ra of the second facing surface 7 is larger than the center line average roughness Ra of the first facing surface 6, a flow from the second facing surface 7 toward the first facing surface 6 occurs. Thus, the viscosity of the liquid L in the vicinity of the opening 1 can be suppressed, so that the quality of the liquid L can be stabilized. When the liquid L is ink, the increase in the viscosity of the ink is suppressed, so that a high-quality image can be obtained.

  In particular, the difference between the center line average roughness Ra of the first facing surface 6 and the center line average roughness Ra of the second facing surface 7 is preferably 0.4 μm or more.

  Further, the center line average roughness Ra of the first facing surface 6 may be smaller than the center line average roughness Ra of the side surface 8 of the flow path 2 that intersects the virtual surface V including the second facing surface 7.

  With such a configuration, the flow resistance of the liquid L that flows along the vicinity of the first facing surface 6 has a flow resistance of the liquid L that flows along the vicinity of the side surface 8 that has a larger centerline average roughness Ra than the first facing surface 6. Since it can be made lower than the channel resistance, the discharge efficiency of the liquid L toward the channel 2 can be further increased.

  In particular, the difference between the center line average roughness Ra of the first facing surface 6 and the center line average roughness Ra of the side surface 8 of the flow path 2 intersecting the virtual surface V including the second facing surface 7 is 0.4 μm or more. It is good to be.

  Further, the center line average roughness Ra of at least one of the side surfaces 8 may be smaller than the center line average roughness Ra of the second facing surface 7.

  With such a configuration, the flow path resistance of the liquid L flowing along the vicinity of the side surface 8 can be made lower than the flow path resistance of the liquid L flowing along the vicinity of the second facing surface 7. The liquid discharge efficiency can be further increased.

  In particular, the difference between the center line average roughness Ra of the side surface 8 and the center line average roughness Ra of the second facing surface 7 is preferably 0.4 μm or more.

  The centerline average roughness Ra can be measured using a surface roughness measuring machine (manufactured by Kosaka Laboratory, Surfcoder (SE500A or its successor model)) in accordance with JIS B 0601-1982. it can. As measurement conditions, the radius of the stylus is 5 μm, the material of the stylus is diamond, the measurement length is 0.5 mm (longitudinal direction of the lid 4 and the base 3), the cutoff value is 0.8 mm, and the scanning speed is 0. It may be set to 1 mm / second.

  When measured with the surface roughness measuring instrument and measurement conditions, for example, the center line average roughness Ra of the first facing surface 6 is 0.8 μm or more and 1.5 μm or less, and the center line average roughness of the second facing surface 7 is Ra is 2.0 μm or more and 6.3 μm or less, and the center line average roughness Ra of the side surface 8 is 1.2 μm or more and 3.2 μm or less.

  Further, as shown in FIG. 1 (c), a first covering portion 9 that covers the first facing surface 6 and the side surface 8 of the flow path 2 adjacent to the joining region between the lid 4 and the base 3. May be provided.

The bonding region refers to a bonding layer. With such a configuration, the rigidity in the bonding region is increased, so that the bending occurring in the longitudinal direction of the lid 4 and the substrate 3 and the direction perpendicular to the longitudinal direction is reduced. be able to.

  In addition, the 1st coating | coated part 9 should just coat | cover the at least one part of the 1st opposing surface 6, and the at least one part of the side surface 8. FIG.

  Further, the base 3, the lid 4 and the first cover 9 are made of ceramics, and the average diameter of the closed pores of the first cover 9 is 0 of the average diameter of the closed pores of the base 3 and the lid 4. It may be 8 times or more and 1.5 times or less.

  When the average diameter of the closed pores of the first covering portion 9 is 1.5 times or less than the average diameter of the closed pores of the base body 3 and the lid 4, the closed pores of the first covering portion 9 serving as a destruction source Since it is sufficiently small, breakage of the flow path member 30 starting from the closed pores of the first covering portion 9 can be suppressed.

  The average diameters of the closed pores of the first covering portion 9, the base body 3, and the lid body 4 are measured by the following method.

  First, the cross sections of the first covering portion 9, the base body 3 and the lid body 4 are mirror-finished, and the cross section of each member is set to a magnification of 500 times using a scanning electron microscope, for example, the lateral length is 256 μm. The observation range in which the length in the vertical direction is 192 μm is set.

  Using this observation range as an object of observation, a method called particle analysis of image analysis software “A image-kun (Ver2.52)” (registered trademark, manufactured by Asahi Kasei Engineering Co., Ltd., hereinafter simply referred to as image analysis software). By applying, the average diameter of closed pores can be determined. The average diameter of the closed pores is an average value of the equivalent circle diameter.

In the analysis, the particle brightness, which is the setting condition of the particle analysis, is darkened, the binarization method is manual, the threshold is 70 to 100, the small figure removal area is 0.3 μm ^2, and the noise removal filter is provided.

In the above measurement, the threshold value is set to 70 to 100. However, the threshold value may be adjusted according to the brightness of the image in the observation range, and the brightness of the particle is darkened and binarized. Is set to manual, the small figure removal area is 0.3 μm ² and the noise removal filter is provided, and the threshold value may be adjusted so that the marker appearing in the image matches the closed pore shape.

  Further, as shown in FIG. 1 (d), the first covering portion 9 may become thinner as the distance from the side surface 8 of the flow path 2 increases.

  With such a configuration, since the liquid L flowing along the surface of the first covering portion 9 becomes a laminar flow, the flow path resistance can be lowered.

  FIG. 2 is a cross-sectional view illustrating another example of the flow path member of the present disclosure.

  As shown in FIG. 2, the contact portion between the second facing surface 7 and the side surface 8 of the flow path 2 may have a predetermined curvature in a sectional view.

  With such a configuration, as shown in FIG. 1, cracks are less likely to occur from the contact portion than when the side surface 8 intersects the virtual surface V including the second facing surface 7 in a substantially perpendicular state.

  FIG. 3 is a cross-sectional view illustrating another example of the flow path member of the present disclosure.

As shown in FIG. 3, the second facing surface 7 may be a curved surface that is convex in a direction away from the first facing surface 6.

  With such a configuration, cracks are less likely to occur, and the rigidity of the base 3 is increased, so that the deflection generated in the base 3 can be reduced.

  4A and 4B show another example of the flow path member of the present disclosure. FIG. 4A is a cross-sectional view, and FIGS. 4B and 4C are cross-sectional views in which a portion B is enlarged.

  A flow path member 40 shown in FIG. 4 is a liquid discharge head, and is an element that generates energy for discharging liquid from the discharge port 10, provided corresponding to the discharge port 10 that discharges liquid and the discharge port 10. (Not shown), an element substrate 12 including an element inside, a support substrate 14 having a communication port 13 that supports the element substrate 12 and opens toward the discharge port 10, and a support substrate 14 Provided on the back side of the substrate 14 is a supply path 16 for supplying the liquid to the communication port 13 via the individual supply port 15 and a recovery path (not shown) for collecting the liquid via an individual liquid recovery port (not shown). A long lid body 20 in which a liquid supply / recovery member 17, a plurality of first through holes 18 for discharging liquid to the outside, and a plurality of second through holes 19 for recovering liquid from the outside are arranged in the longitudinal direction. And the first through hole 18 An elongated shape including a first flow path 21 that communicates with the first through hole 18 and a second flow path 22 that communicates with the second through hole 19 and collects the liquid from the second through hole 19. The lid body 20 and the base body 23 are joined in the vertical direction.

  Here, the liquid is, for example, ink, and the element that generates energy is, for example, an electrothermal conversion element or a piezoelectric element. In addition, in the example illustrated in FIG. 4, the outside refers to the liquid supply / recovery member 17, the support substrate 14, and the element substrate 12, but may simply refer to an external space.

  Lid 20 and base 23 are both made of ceramics mainly composed of aluminum oxide, aluminum nitride, or silicon carbide.

  The first through hole 18 of the flow path member 40 shown in FIG. 4 corresponds to the through hole 5 shown in FIG. 1 and the first flow path 21 corresponds to the flow path 2 shown in FIG. The center line average roughness Ra of the facing surface 24 is smaller than the center line average roughness Ra of the second facing surface 25.

  With such a configuration, the same effect as that obtained with the flow path member 30 shown in FIG. 1 can be obtained.

  In this flow path member 40, one side face 26 on the base 23 side facing the first flow path 21 and a side face 27 on the lid body 20 side are connected in a single plane, and the side face 26, A second covering portion 28 that covers the side surface 27 may be provided.

  With such a configuration, the rigidity at the connection portion between the side surface 26 and the side surface 27 is increased, so that the deflection occurring in the longitudinal direction of the lid 20 and the base body 23 and the direction perpendicular to the longitudinal direction can be reduced. .

  The second covering portion 28 is made of ceramic, and the average diameter of the closed pores of the second covering portion 28 is 0.8 times or more and 1.5 times or less than the average diameter of the closed pores of the base body 23 and the lid 20. It may be.

  When the average diameter of the closed pores of the second covering portion 28 is 1.5 times or less than the average diameter of the closed pores of the base body 23 and the lid 20, the closed pores of the second covering portion 28 serving as a destruction source are reduced. Since it is sufficiently small, breakage of the flow path member 40 starting from the closed pores of the second covering portion 28 can be suppressed.

  What is necessary is just to obtain | require the average diameter of each closed pore of the 2nd coating | cover part 28, the base | substrate 23, and the cover body 20 by the method similar to the method mentioned above.

  Moreover, the 2nd coating | coated part 28 may become thin as it leaves | separates from the side surface 26 by the side of the base | substrate 23. As shown in FIG.

  With such a configuration, since the liquid L flowing along the surface of the second covering portion 28 becomes a laminar flow, the flow path resistance can be lowered.

  Next, a method for manufacturing the flow path member of the present disclosure will be described.

  First, the manufacturing method of the 1st molded object which is the precursor of a cover body, and the 2nd molded object which is a precursor of a base | substrate is demonstrated.

  First, a ball mill, a bead mill, or a vibration mill is composed of a main component of aluminum oxide powder, each powder of magnesium hydroxide, silicon oxide and calcium carbonate, a dispersant for dispersing the aluminum oxide powder as required, and an organic binder. To make a slurry by wet mixing.

Here, when magnesium hydroxide is converted to oxide (MgO), it is 0.3 mass% or more and 0.4 mass% or less, silicon oxide (SiO ₂ ) is 0.04 mass% or more and 0.05 mass% or less, carbonic acid. The mixed powder weighed so that calcium is converted into an oxide (CaO) in the range of 0.01% by mass to 0.02% by mass and the balance is made of aluminum oxide is put into a rotary mill together with a solvent such as water. Then, they are mixed with a ceramic ball made of aluminum oxide having a purity of 99.5% or more and 99.99% or less.

  The wet mixing time is, for example, 40 to 50 hours. Examples of the organic binder include paraffin wax, wax emulsion (wax + emulsifier), PVA (polyvinyl alcohol), PEG (polyethylene glycol), PEO (polyethylene oxide), and the like. Here, the addition amount of the organic binder is 2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the mixed powder.

  Next, after the slurry obtained by the above-mentioned method is spray-granulated to obtain a granule, the granule is subjected to, for example, a pressure pressing method of 80 MPa to 120 MPa, a powder press molding method or a cold isostatic pressing method (rubber press method). ) And the like to obtain a long flat plate-shaped molded body and a long columnar molded body.

  The long flat plate-shaped body is attached to a machining center with a cutting tool made of Compaq diamond or cemented carbide, and a traverse along the longitudinal direction. The first molded body is formed by processing. At this time, 0 cut is performed 2 times or more and 6 times or less so that the surface to be the first facing surface has the lowest possible flatness.

  It should be noted that the moving distance for each pass in the width direction of the cutting tool by traverse processing is made narrower than the width of the cutting tool.

  In order to obtain a channel member in which the difference between the center line average roughness Ra of the first facing surface and the center line average roughness Ra of the second facing surface is 0.4 μm or more, for example, a cutting tool by traverse processing is used. The movement distance for each pass in the width direction is set to 80% or less of the width of the cutting tool.

  In addition, the elongated columnar shaped body is formed by attaching a cutting tool made of cemented carbide to a machining center along a longitudinal direction, and forming a groove that becomes a flow path in the subsequent firing, and grooving along the longitudinal direction. Thus, the second molded body is obtained.

  In addition, in order to obtain a flow path member in which the center line average roughness Ra of the first facing surface intersects with a virtual surface including the second facing surface, the flow path member is smaller than the center line average roughness Ra of the side surface of the flow path. The rotational speed of the spindle of the machining center for obtaining the facing surface may be set to, for example, S800 or more and S2000 or less, and the rotational speed of the spindle of the machining center for obtaining the side face may be set to, for example, S1000 or more and S2300 or less.

  A flow path member in which the difference between the center line average roughness Ra of the first facing surface and the center line average roughness Ra of the side surface of the flow path intersecting a virtual surface including the second facing surface is 0.4 μm or more. In order to obtain, if the rotation speed of the spindle of the machining center for obtaining the first facing surface is, for example, S800 or more and S1500 or less, and the rotation speed of the spindle of the machining center for obtaining the side face is, for example, S1500 or more and S2300 or less. Good.

  In order to obtain a flow path member in which the center line average roughness Ra of at least one of the side surfaces is smaller than the center line average roughness Ra of the second facing surface, the cutting tool is divided into several times and moved in the depth direction. And grooving.

  In order to obtain a channel member in which the difference between the center line average roughness Ra of the side surface and the center line average roughness Ra of the second facing surface is 0.4 μm or more, the cutting tool is used, for example, 5 times or more. Dividing and moving in the depth direction may be performed.

  Here, the contact portion between the second facing surface and the side surface of the flow path is obtained by obtaining a flow path member having a predetermined curvature in a sectional view by using a cutting tool having a tip portion having a predetermined curvature as a machining center. And grooving may be performed along the longitudinal direction of the long columnar shaped body.

  Further, in order to obtain a flow path member having a convex curved surface in a direction away from the first opposing surface, the second facing surface is attached to a machining center with a cutting tool having a convex curved surface at the tip portion. What is necessary is just to do a grooving process along the longitudinal direction of a columnar molded object.

  Next, the manufacturing method of the paste which joins a cover body and a base | substrate is demonstrated.

  A solvent such as water is added to the mixed powder described in the method for producing a molded body in a volume ratio such that mixed powder: solvent = 55-60: 40-45, and the total of the solvent and the mixed powder. Is 100 parts by mass. 8 parts by mass or more and 20 parts by mass or less of a cellulose-based polysaccharide is added to 100 parts by mass, and these are put into a storage container in a stirring device, mixed and stirred to obtain a paste.

  Here, the cellulose-based polysaccharide is, for example, at least one of methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, carboxymethyl ethyl cellulose, and carboxyethyl cellulose.

  And after apply | coating the said paste to the joint surface of a 2nd molded object, the 1st molded object and the 2nd molded object are piled up in the state which faced each joint surface of a 1st molded object and a 2nd molded object. For example, a composite molded body can be obtained by pressurizing the pressure in the range of 0.01 MPa to 1 MPa.

  Here, in order to obtain the flow path member provided with the first covering portion, the paste is applied to the joint surface of the second molded body and the side surface of the first molded body intersecting the joint surface, What is necessary is just to pressurize using the same method.

  A flow path member in which the average diameter of each closed pore of the first covering portion or the second covering portion is 0.8 times or more and 1.5 times or less than the average diameter of each closed pore of the base body and the lid. In order to obtain, it is good to set the rotation speed of a stirring apparatus to 1200 rpm or more and 1600 rpm or less, and to set rotation time to 5 minutes or more and 15 minutes or less.

  Further, in order to obtain a flow path member provided with the second covering portion, after applying the paste to the side surface of the second molded body and the side surface of the first molded body connected to the side surface, the same method as the above method is used. Use and pressurize.

  In addition, in order to obtain a flow path member in which at least one of the first covering portion and the second covering portion is thinned away from the side surface of the base body, after applying paste to the side surface of the molded body, the side surface of the molded body What is necessary is just to arrange a shape so that it may become thin as it leaves | separates from.

  Next, the paste is dried by maintaining the humidity at 40% or higher at room temperature for 12 hours or more and 48 hours or less.

  Thereafter, the flow path member can be obtained by firing the composite molded body by holding at a temperature of 1500 ° C. or higher and 1700 ° C. or lower for 5 hours to 8 hours in an air atmosphere.

  In the flow path member obtained by such a manufacturing method, the center line average roughness Ra of the first facing surface can be made smaller than the center line average roughness Ra of the second facing surface. The flow resistance of the liquid flowing along the second opposing surface can be made lower than the flow resistance of the liquid flowing along the vicinity of the second facing surface, and the discharge efficiency can be increased.

DESCRIPTION OF SYMBOLS 1: Opening 2: Channel 3: Base | substrate 4: Cover body 5: Through-hole 6: 1st opposing surface 7: 2nd opposing surface 8: Side surface 9: 1st coating | coated part 10: Discharge port 11: Pressure chamber 12: Element substrate 13: Communication port 14: Support substrate 15: Individual supply port 16: Supply path 17: Liquid supply / recovery member 18: First through hole 19: Second through hole 20: Lid 21: First flow path 22: 2nd flow path 23: Base | substrate 24: 1st opposing surface 25: 2nd opposing surface 26, 27: Side surface 28: 2nd coating | coated part 30, 40: Channel member

Claims (14)

A substrate comprising a flow path having an opening;
A lid joined to the base so as to close the opening;
The lid includes a through hole that discharges liquid passing through the opening to the outside,
The lid body has a first facing surface facing the flow path, and the base body has a second facing surface facing the flow path and facing the first facing surface,
A flow path member in which the center line average roughness Ra of the first facing surface is smaller than the center line average roughness Ra of the second facing surface.   2. The flow path member according to claim 1, wherein a difference between a center line average roughness Ra of the first facing surface and a center line average roughness Ra of the second facing surface is 0.4 μm or more.   The center line average roughness Ra of the first facing surface is smaller than the center line average roughness Ra of the side surface of the flow path intersecting a virtual surface including the second facing surface. The flow path member described.   The difference between the center line average roughness Ra of the first facing surface and the center line average roughness Ra of the side surface of the flow path intersecting a virtual surface including the second facing surface is 0.4 μm or more. Item 4. The flow path member according to Item 3.   5. The flow path member according to claim 3, wherein a center line average roughness Ra of at least one of the side surfaces is smaller than a center line average roughness Ra of the second facing surface.   6. The flow path member according to claim 3, wherein a difference between the center line average roughness Ra of the side surface and the center line average roughness Ra of the second facing surface is 0.4 μm or more. .   The first covering portion that covers the first facing surface and the side surface of the flow path is provided adjacent to the bonding region between the lid and the base body. The channel member according to any one of the above.   The base body, the lid body, and the first covering portion are made of ceramics, and an average diameter of closed pores of the first covering portion is 0.8, which is an average diameter of the closed pores of the base body and the lid body. The flow path member according to claim 7, wherein the flow path member is not less than twice and not more than 1.5 times.   The flow path member according to claim 7 or 8, wherein the first covering portion becomes thinner as the distance from the side surface of the flow path increases.   The flow path member according to claim 1, further comprising a second covering portion that covers the side surface of the base and the side surface of the lid.   The second covering portion is made of ceramic, and the average diameter of closed pores of the second covering portion is 0.8 times or more and 1.5 times or less than the average diameter of the closed pores of the base and the lid. The flow path member according to claim 10, wherein   The flow path member according to claim 10 or 11, wherein the second covering portion becomes thinner as the distance from the side surface of the base body increases.   The flow path member according to claim 1, wherein a contact portion between the second facing surface and the side surface of the flow path has a predetermined curvature in a cross-sectional view.   The flow path member according to claim 1, wherein the second facing surface is a curved surface that is convex in a direction away from the first facing surface.

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