JP2005153190A - Manufacturing method for inkjet head, head chip of inkjet head, and inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which can easily make an AL precision uniform for all of nozzles without requiring high positional precision at the time of bonding a cover substrate in an inkjet head in multi-nozzle formation with two rows of nozzle arrays. <P>SOLUTION: Channel groove formation face sides of two channel substrates in which many parallel channel grooves separated by partition walls formed of a piezoelectric material are recessed at one-side faces are bonded to both faces of the cover substrate longer than a length in the arrangement direction of the channel grooves at the channel substrate so that both ends of the cover substrate come out of both ends in the arrangement direction of the channel grooves at each channel substrate. Thereafter, each channel substrate and the cover substrate are cut along the arrangement direction of the channel grooves on the basis of parts coming out of each channel substrate at the cover substrate as a reference, whereby a head chip is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an ink jet head having two nozzle rows, an ink jet head chip, and an ink jet head.

  2. Description of the Related Art Conventionally, an inkjet head described in Patent Document 1 is known as an inkjet head that is provided with two nozzle rows each formed by arranging a plurality of nozzles and is designed to be multi-nozzles.

  10 to 12 show an example of a method for manufacturing the ink jet head described in Patent Document 1. FIG. As shown in FIG. 10 (a), the channel substrates 100A and 100B made of a piezoelectric material such as piezoelectric ceramic have a large number of channel grooves 101A and 101B parallel to each other in the middle of one side using a dicing blade or the like. In addition, a drive voltage application electrode (not shown) for deforming the partition walls 102A, 102B between the channel grooves 101A, 101B into a U-shape in the channel grooves 101A, 101B. The surfaces opposite to the channel grooves 101A and 101B forming surfaces of the channel substrates 100A and 100B are bonded to each other. Here, as shown in FIG. 10B, six channel grooves 101A and 101B are formed in each of the channel substrates 100A and 100B.

  Next, the channel grooves 101A, 101B of the channel substrates 100A, 100B are arranged in the substantially central portion of the channel substrates 100A, 100B on the side where the channel grooves 101A, 101B are formed (the horizontal direction in FIG. 10B). The cover substrates 200A and 200B having the same width as that of the channel grooves 101A and 101B (the length in the horizontal direction in FIG. 10A) are bonded to each other.

  Thereafter, the substrate end R1 or R2 with reference to the substrate end R1 (see FIG. 10A) of the bonded channel substrates 100A and 100B or the substrate end R2 of the cover substrate 200A or 200B (see FIG. 10A). Alignment is performed so that the reference line of the cutting machine is matched with the cutting machine, and a position at a predetermined distance in parallel with the reference position is taken as a cut line, and the channel substrates 100A and 100B and the cover substrate are formed along the cut line. When cut along the alignment direction of the channel grooves 101A and 101B over 200A and 200B at a time, as shown in FIG. 101B, the rear end (right end in the figure) gradually becomes shallower in an inclined manner, and part of the rear end side Leaving the cover substrate 200A, the head chip 300 which is covered by 200B is created. Two head chips 300 are obtained from the one shown in FIG.

Further, as shown in FIG. 12, a single nozzle plate 400 having nozzle holes 401A and 401B corresponding to the channel grooves 101A and 101B is bonded to the front end surface of the head chip 300, and a cover substrate is provided. The manifolds 500A and 500B are bonded so as to cover the rear ends of the channel grooves 101A and 101B that are not covered by the 200A and 200B, and the ink supply chambers 501A and 501B formed in the manifolds 500A and 500B and the respective The channel grooves 101A and 101B are communicated with each other.
JP 2001-315333 A

  As described above, the rear end sides of the channel grooves 101A and 101B gradually become shallower in an inclined manner, and the partition walls 102A and 102B are deformed into a dogleg shape with respect to the ink in the channel grooves 101A and 101B. In the case of an inkjet head that is changed and ejected from the nozzle holes 401A and 401B, the pressure waves generated in the channel grooves 101A and 101B are caused by the nozzle surface on which the nozzle holes 401A and 401B are formed and the opposite end side. Reflected between two surfaces of the manifolds 500A and 500B. The pulse width of the drive signal for deforming the partition walls 102A and 102B into a U-shape is AL (Acoustic Length≈L / L between the two surfaces), which is the time for the pressure wave to pass through the two reflecting surfaces. The sound velocity in the channel groove Cn) is set. Therefore, in the channel grooves 101A and 101B, the length L between the nozzle surface and the boundary surface between the manifolds 500A and 500B (hereinafter referred to as L length) determines the ink ejection characteristics of the inkjet head. In the case of the head chip 300 shown in FIG. 11, this L length is determined by the length along the length direction of the channel grooves 101A and 101B of the cover substrates 200A and 200B.

  However, as shown by the two-dot chain line in FIG. 10 (a), the bonding positions of the cover substrates 200A and 200B positioned above and below the channel substrates 100A and 100B with the bonded channel substrates 100A and 100B interposed therebetween are shown. In the case where they are provided so as to be shifted from each other, even if they are cut with reference to either of the substrate ends R1 and R2, as indicated by a two-dot chain line in FIG. The length (length Lb) is different from the L length (length La) of the channel groove 101A having the other cover substrate 200A, and the accuracy of AL differs between the nozzle arrays, resulting in ink ejection characteristics. A big difference will occur.

  For example, in the case where the cover substrate 200A is bonded to be inclined with respect to the direction in which the channel grooves 101A are arranged, if the substrate end R1 is cut as a reference, the AL accuracy is improved between the two nozzle rows. In addition to the difference, the L length also differs between the channel grooves 101A, resulting in variations in the accuracy of the AL. Even when the substrate end R2 is cut as a reference, the two nozzle rows are similar to the above. The accuracy of AL differs between the two.

  Therefore, in the conventional manufacturing method, high positional accuracy is required when the cover substrates 200A and 200B are bonded, which causes a decrease in productivity. For this reason, when manufacturing a multi-nozzle inkjet head, it is desirable to easily make the AL accuracy uniform for all nozzles without requiring high positional accuracy when the cover substrate is bonded. ing.

  Accordingly, an object of the present invention is to easily uniform the AL accuracy with all the nozzles without requiring high positional accuracy when bonding the cover substrate in the multi-nozzle inkjet head having two nozzle rows. An object of the present invention is to provide a manufacturing method that can be realized.

  Another object of the present invention is to provide a head chip capable of avoiding damage to an expensive channel substrate by enabling easy holding without directly touching the channel substrate.

  Another object of the present invention is to provide an ink jet head which can avoid damage to an expensive channel substrate by enabling easy holding without directly touching the channel substrate.

  The other subject of this invention becomes clear by the following description.

  The above problems are solved by the following inventions.

(Claim 1)
Each channel groove forming surface side of two channel substrates in which a large number of parallel channel grooves separated by a partition made of a piezoelectric material are provided on one side is longer than the length of the channel grooves on the channel substrate in the arrangement direction. After adhering to both sides of a single long cover substrate so that both ends of the cover substrate protrude from both ends of the channel grooves in the channel substrate in the alignment direction, each cover substrate protrudes from the channel substrate in the cover substrate. A method of manufacturing an ink-jet head, comprising: a step of creating a head chip by cutting each channel substrate and the cover substrate along an arrangement direction of the channel grooves with reference to a site.

(Claim 2)
2. The method of manufacturing an ink jet head according to claim 1, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.

(Claim 3)
A head chip of an ink jet head in which each channel groove forming surface side of a channel substrate in which a large number of parallel channel grooves separated from each other by a partition made of a piezoelectric material is formed on both sides of a single cover substrate is bonded. The cover substrate is longer than the length of the channel grooves in the channel substrate in the alignment direction, and both ends of the cover substrate protrude from both ends of the channel grooves in the channel substrate in the alignment direction. A head chip for an ink jet head, comprising:

(Claim 4)
4. The head chip of an ink jet head according to claim 3, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.

(Claim 5)
An inkjet head in which each channel groove forming surface side of a channel substrate having a plurality of parallel channel grooves provided on both sides of a single cover substrate by a partition made of a piezoelectric material is bonded to each side. The cover substrate is longer than the length of the channel grooves in the channel substrate in the alignment direction, and both ends of the cover substrate have protrusions protruding from both ends of the channel grooves in the channel substrate in the alignment direction. An ink jet head characterized by comprising:

(Claim 6)
6. The inkjet head according to claim 5, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.

  According to the present invention, there is provided a method for manufacturing a multi-nozzle inkjet head capable of easily equalizing AL accuracy with all nozzles without requiring high positional accuracy when bonding a cover substrate. Can do.

  Further, according to the present invention, it is possible to provide a head chip capable of avoiding damage to an expensive channel substrate by enabling easy holding without directly touching the channel substrate.

  Furthermore, according to the present invention, it is possible to provide an ink jet head capable of avoiding damage to an expensive channel substrate by enabling easy holding without directly touching the channel substrate.

  Hereinafter, an example of a method for manufacturing an inkjet head according to the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a state in which two channel substrates 1A and 1B and one cover substrate 2 are bonded, and FIG. 2 is a plan view seen from the II direction of FIG.

  As shown in FIG. 1, each of the two channel substrates 1A and 1B is mainly composed of a piezoelectric material in which a large number of channel grooves 11A and 11B are parallelly arranged in parallel, and is formed of one cover substrate 2 and Adhering to both surfaces of the two connection substrates 4 and 4 disposed at a predetermined distance from the cover substrate 2 is performed so that the formation surfaces of the channel grooves 11A and 11B face each other.

  As the piezoelectric material, a known piezoelectric material that deforms when a voltage is applied can be used, and examples thereof include a piezoelectric material made of an organic material and a non-metallic piezoelectric material. In particular, the substrate is preferably formed of a non-metallic piezoelectric material, such as a piezoelectric ceramic substrate formed through processes such as molding and firing, or a substrate formed without requiring molding and firing.

In a substrate made of a non-metallic piezoelectric material, lead zirconate titanate (PZT) is preferable as the piezoelectric ceramic substrate formed through processes such as molding and firing. Furthermore, BaTiO ₃ , ZnO, LiNbO ₃ , LiTaO ₃ or the like may be used.

PZT includes PZT (PbZrO ₃ —PbTiO ₃ ) and third component added PZT. As the third component to be added, Pb (Mg _1/3 Nb _2/3 ) O ₃ , Pb (Mn _1/3 Sb _2/3 ) O ₃ , Pb (Co _1/3 Nb _2/3 ) O _3, etc. is there.

  Moreover, in the board | substrate which consists of nonmetallic piezoelectric materials, as a board | substrate formed without requiring shaping | molding and baking, it can form by the sol-gel method, the laminated substrate coating method, etc., for example.

  In order to recess the channel grooves 11A and 11B with respect to the channel substrates 1A and 1B, as shown in FIG. 6, a mask for electrode formation is formed in advance on the surface of the channel substrates 1A and 1B with a dry film 80, The dry films 80 corresponding to the respective electrode formation regions 80a are removed by exposure processing at both ends (left and right ends in FIG. 5) of the surfaces of the substrates 1A and 1B to expose the surfaces of the channel substrates 1A and 1B. deep.

  After that, as shown in FIG. 7, a large number of grooves are cut in parallel from the surface of the channel substrates 1A and 1B by a dicing blade 90. The individual channel grooves 11A and 11B are formed so that the dicing blade 90 is lowered from the electrode forming region 80a at one end of the channel substrates 1A and 1B to the surface of the channel substrates 1A and 1B, and then has the same depth in the direction of the arrow. The dicing blade 90 is moved to reach the electrode forming region 80a at the end to grind the groove, and when reaching the electrode forming region 80a at the other end, the dicing blade 90 is raised to form a recess. As a result, the channel grooves 11A and 11B and the partition walls 12A and 12B made of the piezoelectric material left between them are alternately arranged in parallel on the channel substrates 1A and 1B. As it goes to both ends of the channel substrates 1A and 1B, it becomes gradually shallower and becomes inclined portions 11A ′ and 11B ′ (see FIG. 1), and finally disappears.

  After the channel grooves 11A and 11B are formed in the channel substrates 1A and 1B in this way, the surface of the channel substrates 1A and 1B in a state where the dry film 80 is coated is applied to the surface by plating, vapor deposition, sputtering, or the like. 13A and 13B are formed. The metal forming the electrodes 13A and 13B includes Ni (nickel), Co (cobalt), Cu (copper), Al (aluminum), etc., but Ni and Cu are preferable, and Ni is particularly preferable. Thus, the electrodes 13A and 13B are formed only in the respective electrode formation regions 80a that are not covered with the dry film 80 and the respective channel grooves 11A and 11B that are ground by the dicing blade 90.

  At this time, as shown in FIG. 8, the electrodes 13A and 13B in the channel grooves 11A and 11B are inclined portions 11A ′ located at both ends along the length direction of the channel grooves 11A and 11B of the channel substrates 1A and 1B, 11B 'is drawn out to the surface of the channel substrates 1A and 1B through 11B'. Thus, the electrodes 13A and 13B are arranged in parallel at the same pitch as the channel grooves 11A and 11B on the surfaces on both ends of the channel substrates 1A and 1B.

  The channel substrates 1A and 1B made of a piezoelectric material are each subjected to polarization treatment. When a voltage is applied from the direction perpendicular to the polarization direction by applying a voltage to the electrodes 13A and 13B formed on the surfaces of the partition walls 12A and 12B, The partition walls 12A and 12B are shear-deformed into a dogleg shape by the piezoelectric sliding effect, whereby the internal volume of the channel grooves 11A and 11B is changed, and the pressure in the ink in the channel grooves 11A and 11B is changed.

  For the cover substrate 2, for example, a material such as a ceramic containing aluminum nitride as a component, a non-polarized piezoelectric material, or a liquid crystal polymer can be used. Furthermore, it is preferable that the thermal expansion coefficient is ± 2 ppm / ° C. of the thermal expansion coefficient of the channel substrates 1A and 1B. By setting the thermal expansion coefficient within this range, separation or the like due to the difference in thermal expansion coefficient does not occur between the substrates.

  The length of the cover substrate 2 (the length in the left-right direction in FIG. 1) is shorter than the length of the channel grooves 11A and 11B provided in the channel substrates 1A and 1B, and the width of the cover substrate 2 (channel The length along the alignment direction of the grooves 11A and 11B is longer than the width of each channel substrate 1A and 1B (the length along the alignment direction of the channel grooves 11A and 11B) as shown in FIG. . In FIG. 2, only the channel substrate 1A and the channel groove 11A are shown. Then, as shown in FIG. 9, the single cover substrate 2 is disposed so as to be positioned at a substantially central portion in the length direction of the channel groove 11B of one channel substrate 1B, and an epoxy adhesive or the like is used. And glue.

  On the other hand, the connection substrates 4 and 4 can be formed of the same material as the cover substrate 2 with the same width as the channel substrates 1A and 1B. In each connection substrate 4, 4, each surface in contact with each channel substrate 1 A, 1 B has connection electrodes 41 A, 41 B at the same number and the same pitch as the electrodes 13 A, 13 B formed to the surface of each channel substrate 1 A, 1 B. Is patterned. In this way, in order to form the connection electrodes 41A and 41B, similarly to the method of forming the electrodes 13A and 13B, both surfaces of the connection substrates 4 and 4 are covered with a dry film, and the connection electrode formation region is exposed. Then, the electrode-forming metal is formed by plating, vapor deposition, sputtering, or the like, and then the remaining dry film may be removed.

  The connection substrates 4 and 4 are spaced apart from the cover substrate 2 so that the inclined portion 11B ′ of the channel groove 11B faces the cover substrate 2 at each end of the upper surface of the channel substrate 1B. Are arranged so that the end portions of the connection substrates 4 and 4 protrude from both ends of the channel substrate 1B, and the connection electrodes 41B formed on one surface of the connection substrates 4 and 4 are provided. It arrange | positions so that it may electrically connect with each electrode 13B on the surface of channel substrate 1B, and it adhere | attaches on the surface of channel substrate 1B using an anisotropic conductive film etc.

  Thereafter, the other channel substrate 1A is bonded to these upper surfaces so that the channel groove 11A formation surface side faces down to face the channel substrate 1B, and the channel substrates 1A, 1B, 1B, and 2B shown in FIGS. An integrated body of the cover substrate 2 and the connection substrates 4 and 4 is created. As a result, a space serving as a common ink chamber 5 for supplying ink into the channel grooves 11A and 11B is formed in a space formed between the cover substrate 2 and the connection substrates 4 and 4.

  Here, as described above, since the width of the cover substrate 2 is longer than the width of each of the channel substrates 1A and 1B, both ends of the channel substrates 1A and 1B in the width direction are formed as shown in FIG. The end portions in the width direction of the cover substrate 2 protrude from the respective sides. The cover substrate 2 is preferably arranged and bonded such that the protruding amounts α and α of the protruding portions 21 and 21 are substantially the same.

  After the two channel substrates 1A and 1B are bonded to the one cover substrate 2 and the two connection substrates 4 and 4 in this way, as shown in FIG. 2, the channel grooves 11A and 11B are arranged in the direction of alignment. Two head chips are divided and formed by cutting along the cut lines C1 and C2.

  Here, the cut line C1 is based on the substrate end along the Ra-Ra line in the drawing of the protruding portion 21 protruding from the width direction end of each channel substrate 1A, 1B in the cover substrate 2, and is parallel to this substrate end. And a predetermined distance.

  Similarly, the cut line C2 is set at a position that is parallel to a predetermined distance from the end of the substrate along the line Rb-Rb in the drawing of the protruding portion 21. Thus, when cutting along the cut lines C1 and C2, the cut surfaces are parallel to the substrate end along the Ra-Ra line and the substrate end along the Rb-Rb line, respectively.

  The protruding amounts α and α of the protruding portions 21 and 21 of the cover substrate 2 are each preferably 1 mm or more, and more preferably 5 mm or more so that this can be easily confirmed with reference to the substrate edge. . The upper limit of the protrusion amount α is not particularly limited, but if it is too large, the head chip may be increased in size and the amount of use of the cover substrate 2 may be increased, resulting in an increase in cost. It is done.

  As shown in FIG. 3A, the obtained head chip 10 has the same cover substrate 2 for the channel groove 11A arranged on the upper side in the drawing and the channel groove 11B arranged on the lower side in the drawing. Become. Therefore, the L length of the channel groove 11A and the L length of the channel groove 11B are common to the length L of the cover substrate 2, and there is no difference between the two.

  Further, since the cut surface at the left end in FIG. 3 is parallel to the substrate end of the cover substrate 2 along the Ra-Ra line (or Rb-Rb line), the cover substrate 2 is slightly slightly in relation to the channel substrates 1A and 1B. Even if they are tilted and bonded, the variation in the L length in each channel groove 11A and the variation in the L length in each channel groove 11B that respectively constitute the nozzle row does not occur, and the head chip 10 as a whole AL accuracy can be made uniform.

  Furthermore, since the protruding portions 21 and 21 of the cover substrate 2 protrude from both sides of the head chip 10 formed in this way, the channel substrates 1A and 1B are formed on both surfaces of the cover substrate 2, respectively. When it is necessary to hold the head chip 10 when adhering or transferring between processes, the protruding portions 21 and 21 can be used as a holding portion. By holding or holding in the hand, the head chip 10 can be handled without directly touching the channel substrates 1A and 1B, and damage to the expensive channel substrates 1A and 1B can be avoided. it can.

  After the head chip 10 is formed in this way, as shown in FIG. 4, the nozzle plate 3 in which the nozzle holes 31A and 31B are opened at the positions corresponding to the channel grooves 11A and 11B is bonded to the cut surface. At the same time, FPCs (flexible printed circuit boards) 6A and 6B in which wirings electrically connected to drive circuits (not shown) are formed on the connection electrodes 41A and 41B of the connection board 4 are anisotropically conductive. Join using a film or the like.

  Further, as shown in FIG. 5, manifold members 7 and 7 are bonded so as to close both ends of the common ink chamber 5 opened on both sides of the head chip 10, thereby completing the ink jet head H. The manifold members 7 and 7 shown here are each formed in a U shape by, for example, engineering plastics, and are attached over the upper surface, side surface, and lower surface of the head chip 10. An ink supply port 71 that communicates with the common ink chamber 5 is formed in at least one of the manifold members 7 and 7.

  Here, since the protruding portions 21 and 21 of the cover substrate 2 protrude from the both sides of the head chip 10, respectively, when the manifold members 7 and 7 are bonded, the protruding portions 21 and 21 are used as a reference. As shown by the arrows in FIG. 5, the manifold members 7 and 7 are abutted against the protruding portions 21 and 21 so that their bonding positions can be easily positioned.

  Further, even when the inkjet head H is completed, the protruding portions 21 and 21 are left so that the protruding portions 21 and 21 are used as the holding portions when it is necessary to hold the protruding portions 21 and 21 for transferring the inkjet head H or the like. In addition, the inkjet head H can be handled without directly touching the channel substrates 1A and 1B, and damage to the expensive channel substrates 1A and 1B can be avoided. Also, when protruding and accommodated, the protruding portions 21 and 21 can be used as positioning reference, and attachment with high accuracy can be easily performed.

It is a figure explaining the manufacturing method of the ink jet head concerning the present invention, and a sectional view showing the state where two channel substrates and one cover substrate were pasted up Plan view seen from direction II in Fig. 1 (A) is sectional drawing which shows the structure of the head chip based on this invention, (b) is the top view Sectional drawing which shows the structure of the inkjet head which concerns on this invention The perspective view which shows the manufacturing method of the inkjet head which concerns on this invention The figure explaining the manufacturing method of the inkjet head which concerns on this invention The figure explaining the manufacturing method of the inkjet head which concerns on this invention The figure explaining the manufacturing method of the inkjet head which concerns on this invention The figure explaining the manufacturing method of the inkjet head which concerns on this invention It is a figure explaining the manufacturing method of the conventional inkjet head, (a) is sectional drawing which shows the state which adhere | attached two channel substrates and two cover substrates, (b) is bb of (a). Sectional view along the line Sectional view showing the structure of a conventional head chip Sectional view showing the structure of a conventional inkjet head

Explanation of symbols

1A, 1B: Channel substrate 10: Head chip 11A, 11B: Channel groove 12A, 12B: Partition wall 13A, 13B: Electrode 2: Cover substrate 21: Protruding part 3: Nozzle plate 31A, 31B: Nozzle hole 4: Connection substrate 41A, 41B: Connection electrode 5: Common ink chamber 6A, 6B: FPC
7: Manifold member 71: Ink supply port 80: Dry film 90: Dicing blade H: Inkjet head

Claims (6)

  Each channel groove forming surface side of two channel substrates in which a large number of parallel channel grooves separated by a partition made of a piezoelectric material are provided on one side is longer than the length of the channel grooves on the channel substrate in the arrangement direction. After adhering to both sides of a single long cover substrate so that both ends of the cover substrate protrude from both ends of the channel grooves in the channel substrate in the alignment direction, each cover substrate protrudes from the channel substrate in the cover substrate. A method of manufacturing an ink-jet head, comprising: a step of creating a head chip by cutting each channel substrate and the cover substrate along an arrangement direction of the channel grooves with reference to a site.   2. The method of manufacturing an ink jet head according to claim 1, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.   A head chip of an ink jet head in which each channel groove forming surface side of a channel substrate in which a large number of parallel channel grooves separated from each other by a partition made of a piezoelectric material is formed on both sides of a single cover substrate is bonded. The cover substrate is longer than the length of the channel grooves in the channel substrate in the alignment direction, and both ends of the cover substrate protrude from both ends of the channel grooves in the channel substrate in the alignment direction. A head chip for an ink jet head, comprising:   4. The head chip of an ink jet head according to claim 3, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.   An inkjet head in which each channel groove forming surface side of a channel substrate having a plurality of parallel channel grooves provided on both sides of a single cover substrate by a partition made of a piezoelectric material is bonded to each side. The cover substrate is longer than the length of the channel grooves in the channel substrate in the alignment direction, and both ends of the cover substrate have protrusions protruding from both ends of the channel grooves in the channel substrate in the alignment direction. An ink jet head characterized by comprising:   6. The inkjet head according to claim 5, wherein the protruding length of each portion of the cover substrate that protrudes from each channel substrate is 1 mm or more.

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