WO2020170319A1 - Nozzle plate and manufacturing method thereof, inkjet head, and image forming apparatus - Google Patents

Nozzle plate and manufacturing method thereof, inkjet head, and image forming apparatus Download PDF

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Publication number
WO2020170319A1
WO2020170319A1 PCT/JP2019/005957 JP2019005957W WO2020170319A1 WO 2020170319 A1 WO2020170319 A1 WO 2020170319A1 JP 2019005957 W JP2019005957 W JP 2019005957W WO 2020170319 A1 WO2020170319 A1 WO 2020170319A1
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WO
WIPO (PCT)
Prior art keywords
round portion
nozzle plate
round
nozzle
inkjet head
Prior art date
Application number
PCT/JP2019/005957
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French (fr)
Japanese (ja)
Inventor
原　慎太郎
江口　秀幸
Original Assignee
コニカミノルタ株式会社
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Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to JP2021501170A priority Critical patent/JP7287451B2/en
Priority to PCT/JP2019/005957 priority patent/WO2020170319A1/en
Publication of WO2020170319A1 publication Critical patent/WO2020170319A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/16—Production of nozzles

Definitions

  • the present invention relates to a nozzle plate, a method for manufacturing the nozzle plate, an inkjet head, and an image forming apparatus.
  • An inkjet head used in an inkjet printer or the like has a nozzle plate provided with a large number of minute nozzle holes on the ejection surface of droplets (ink).
  • the opening area of each nozzle hole on the ejection side is made smaller, It is required to increase the volume of the nozzle hole.
  • Patent Documents 1 to 4 describe a nozzle plate having a reverse round-shaped nozzle hole in which a flow path width is curvilinearly narrowed from a liquid inflow side to a liquid discharge side. .. It is considered that the nozzle hole having such a shape can increase the volume of the nozzle hole while reducing the opening area on the side where droplets are ejected.
  • Patent Documents 4 and 5 describe nozzle plates having nozzle holes whose cross-sectional shape changes stepwise along the liquid ejection direction.
  • the first silicon layer of an SOI (Silicon on Insulator) wafer is anisotropically etched to form a substantially vertical space on the side where droplets are discharged, and the second silicon of the SOI wafer is formed. Isotropic etching is performed on the layer to form a curved space that connects the above-mentioned substantially vertical space with a narrow channel width, and then a glass substrate having a substantially vertical space into which liquid is introduced is anodically bonded. By doing so, a nozzle plate in which three spaces having different cross-sectional shapes are formed inside the nozzle hole is manufactured.
  • SOI Silicon on Insulator
  • Patent Document 5 a nozzle plate having two steps of tapered holes having different taper angles formed by drilling and pressing is manufactured. ..
  • a nozzle plate having a nozzle hole having a shape capable of increasing the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of the droplet, and a processing method for forming the nozzle hole having the shape are provided. The desire to develop still exists.
  • An object of the present invention is to provide a manufacturing method, an inkjet head including the nozzle plate, and an image forming apparatus including the inkjet head.
  • the above problem is a nozzle plate having a plurality of nozzle holes for ejecting droplets, wherein the nozzle holes are arranged on the most upstream side in the ejection direction of the droplets, and A first round portion whose diameter decreases in a direction, a second round portion which is arranged on the downstream side of the first round portion and whose diameter decreases in the droplet ejection direction, and the second round portion
  • the straight portion having a diameter that is arranged downstream of the round portion and has a constant diameter in the discharge direction of the droplet
  • Each of the first round portion and the second round portion has a shape in which an outer edge is defined by a curved surface that is convex outward, and an outer edge of the first round portion and an outer edge of the second round portion.
  • a single crystal silicon wafer having a resist pattern formed on one surface thereof is subjected to a first isotropic etching step of performing isotropic etching using the resist pattern as a mask, and the single crystal silicon wafer is Using the resist pattern as a mask, a second isotropic etching step of performing isotropic etching under different conditions from the first isotropic etching step and the single crystal silicon wafer are performed using the resist pattern as a mask.
  • a method for manufacturing a nozzle plate which includes an anisotropic etching step of performing isotropic etching in this order.
  • an inkjet head having a pressure chamber with a larger aspect ratio of partition walls and less likely to be destroyed during manufacturing a method for manufacturing the inkjet head, and an image forming apparatus including the inkjet head are provided.
  • FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus using an inkjet method.
  • FIG. 2 is an exploded perspective view showing an outline of an inkjet head used in the image forming apparatus shown in FIG. 1 in the embodiment of the present invention.
  • FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, showing an outline of a head chip included in the inkjet head according to the embodiment of the present invention.
  • FIG. 4 is a cross-sectional view taken along line BB in FIG. 2, showing an outline of a head chip included in the inkjet head according to the embodiment of the present invention.
  • FIG. 5 is a partially enlarged view of a region C in FIG.
  • FIG. 6 is a schematic cross-sectional view of the nozzle hole for showing the volume of the nozzle hole included in the nozzle plate shown in FIG.
  • FIG. 7A is a cross-sectional view showing the shape of a nozzle hole when an upstream round portion is produced by performing isotropic etching only once, and FIG. 7B is isotropic etching performed only once. It is sectional drawing which shows another shape of a nozzle hole at the time of producing the round part by the side of this.
  • 8A to 8C are first process diagrams showing a process of manufacturing the nozzle plate according to the embodiment of the present invention.
  • 9A to 9C are second process charts showing the process of manufacturing the nozzle plate according to the embodiment of the present invention.
  • 10A to 10B are third process charts showing the process of manufacturing the nozzle plate in the embodiment of the present invention.
  • 11A to 11C are fourth process charts showing the process of manufacturing the nozzle plate according to the embodiment of the present invention.
  • the image forming apparatus according to the first embodiment of the present invention can have the same configuration as the image forming apparatus by a known inkjet method except that the image forming apparatus according to the present embodiment has an inkjet head according to the present embodiment described below.
  • the image forming apparatus 100 includes an inkjet head 1, an ink supply device 120, a transport device 130, and a main tank 140.
  • the inkjet head 1 has a plurality of nozzles for ejecting ink droplets onto a recording medium 150 such as paper, which is a printing target.
  • the inkjet head 1 is configured such that a plurality of types of ink having different colors are supplied to specific nozzles.
  • the inkjet head 1 is, for example, arranged so as to be capable of scanning in a direction transverse to the transport direction X of the recording medium 150 on which an image is to be formed. The configuration of the inkjet head 1 will be described later.
  • the transport device 130 is a device for transporting the recording medium 150 to the inkjet head 1.
  • the transport device 130 includes, for example, a belt conveyor 131 and a rotatable feed roller 132.
  • the belt conveyor 131 is composed of rotatable pulleys 133a and 133b, and an endless belt 134 stretched around these pulleys 133a and 133b.
  • the feed roller 132 is arranged at a position facing the pulley 133a on the upstream side in the transport direction X of the recording medium 150 so as to sandwich the belt 134 and the recording medium 150 and feed the recording medium 150 onto the belt 134.
  • the ink supply device 120 is arranged integrally with the inkjet head 1.
  • the ink supply device 120 is arranged for each type of ink. For example, when four color inks of Y (yellow), M (magenta), C (cyan) and K (black) are used, four ink supply devices 120 are arranged in the inkjet head 1.
  • Each ink supply device 120 is supplied with ink in the main tank 140 via a pipe 161 and a valve 164 connected to the main tank 140. Further, each ink supply device 120 communicates with a common ink chamber 2 of the inkjet head 1 described later via a pipe 162, and is connected so as to be able to supply ink of each color to an ink supply port 2 a of a desired common ink chamber 2. There is.
  • the inkjet head 1 is also connected to the main tank 140 by a bypass pipe 163 branched from the pipe 161.
  • a valve 164 that can switch and set a flow path of ink to one or both of the pipe 161 and the bypass pipe 163 is arranged.
  • Each of the pipe 161, the pipe 162, and the bypass pipe 163 is a flexible tube.
  • the valve 164 is, for example, a three-way valve.
  • the main tank 140 is a tank for containing the ink to be supplied to the inkjet head 1.
  • the main tank 140 is arranged separately from the inkjet head 1.
  • the main tank 140 has, for example, a stirring device (not shown).
  • the main tank 140 can be appropriately determined according to the image forming performance and size of the image forming apparatus 100. For example, when the image forming speed of the image forming apparatus is 1 to 3 m 2 /min, the capacity of the main tank 140 is, for example, 1 L.
  • FIG. 2 is an exploded perspective view showing an outline of the inkjet head 1 used in the image forming apparatus 100 described above.
  • the inkjet head 1 has a common ink chamber 2, a holding portion 3, a head chip 4, and a flexible wiring board 5.
  • the common ink chamber 2 is formed in a hollow, substantially rectangular parallelepiped shape, and one surface facing the holding portion 3 is open.
  • An ink supply port 2a for supplying the ink of the ink supply device 120 and an ink discharge port 2b for discharging the ink to the ink supply device 120 are provided on one surface of the common ink chamber 2 facing the opening.
  • the common ink chamber 2 has a filter inside, and removes foreign matters from the ink supplied from the ink supply port 2a by the filter and finely crushes the bubbles contained in the ink.
  • the holding portion 3 is formed in a substantially flat plate shape having an opening 3a at a substantially center thereof, and is arranged so as to cover the opening of the common ink chamber 2.
  • the common ink chamber 2 is connected to one surface of the holding portion 3 so as to cover the opening 3a.
  • the head chip 4 is connected to the other surface of the holding portion 3 so as to cover the opening 3a.
  • the holding unit 3 connects the common ink chamber 2 and the head chip 4 via the opening 3a.
  • An insertion hole 3b is provided on the outer peripheral portion of the holding portion 3.
  • the flexible wiring board 5 is inserted into the insertion hole 3b.
  • One end of the flexible wiring board 5 is connected to the wiring board 50 of the head chip 4 described later.
  • the other end of the flexible wiring board 5 is inserted into the insertion hole 3b provided in the holding portion 3 from the other surface of the holding portion 3 and is drawn out to the common ink chamber 2 side.
  • FIG. 3 is a cross-sectional view taken along line AA in FIG. 2 showing an outline of the head chip 4 included in the inkjet head 1 described above, and FIG. 4 is an outline of the head chip 4 included in the inkjet head 1 described above.
  • FIG. 3 is a sectional view taken along line BB in FIG.
  • the head chip 4 has a nozzle plate 10, an intermediate plate 20, a pressure chamber forming plate 30, a drive plate 40, and a wiring board 50. Further, the head chip 4 is formed by laminating a nozzle plate 10, an intermediate plate 20, a pressure chamber forming plate 30, a drive plate 40, and a wiring board 50 in this order from the ink ejection surface side.
  • a plurality of nozzle holes 11 are formed in the nozzle plate 10.
  • the nozzle hole 11 penetrates from one surface of the nozzle plate 10 to the other surface.
  • the nozzle hole 11 has a cross-sectional shape that is narrowed down so that the tip side, which is an ejection port, has a small diameter, and ejects the ink supplied from the common ink chamber 2 from the ejection port to the outside.
  • a plurality of nozzle holes 11 (for example, 500 to 2000) are provided in the nozzle plate 10 and are arranged in a matrix.
  • the nozzle hole 11 communicates with the pressure chamber 31 formed in the pressure chamber forming plate 30 via the intermediate plate 20 laminated on the nozzle plate 10.
  • a liquid repellent film 13 is formed on the surface of the nozzle plate 10 on the ink ejection side.
  • the intermediate plate 20 is arranged between the nozzle plate 10 and the pressure chamber forming plate 30.
  • the intermediate plate 20 is provided with a first communication hole 21 that connects the nozzle hole 11 and a pressure chamber 31 provided in the pressure chamber forming plate 30 described later.
  • the first communication hole 21 is provided at a position corresponding to the nozzle hole 11 of the nozzle plate 10, and penetrates from one surface to the other surface of the intermediate plate 20.
  • the pressure chamber forming plate 30 has a plurality of pressure chambers 31 and a vibration plate 32.
  • the pressure chamber 31 is provided at a position corresponding to the nozzle hole 11 of the nozzle plate 10 and the first communication hole 21 of the intermediate plate 20. Further, the pressure chamber 31 penetrates from one surface to the other surface of the pressure chamber forming plate 30.
  • the pressure chamber 31 applies an ejection pressure to the ink ejected from the nozzle hole 11 due to its volume variation.
  • a partition 33 is formed between the plurality of pressure chambers 31.
  • the partition 33 is entirely formed of an electroplatable metal such as nickel (Ni). As a result, the rigidity of the partition wall 33 can be made higher, and the inkjet head 1 can have a stable structure that is not easily destroyed by vibration.
  • the diaphragm 32 is arranged so as to cover the opening of the pressure chamber 31 opposite to the intermediate plate 20.
  • the diaphragm 32 is provided with a second communication hole 34 that communicates with the pressure chamber 31.
  • the drive plate 40 is arranged on one surface of the vibration plate 32 opposite to the one surface on the pressure chamber 31 side.
  • the drive plate 40 has a space 41 and a third communication hole 42 that communicates with the second communication hole 34.
  • the space 41 is arranged at a position facing the pressure chamber 31 with the diaphragm 32 interposed therebetween.
  • the actuator 60 is housed in the space 41.
  • the actuator 60 has a piezoelectric element 61, a first electrode 62, and a second electrode 63.
  • the first electrode 62 is laminated on one surface of the diaphragm 32.
  • An insulating layer may be arranged between the first electrode 62 and the diaphragm 32.
  • the piezoelectric element 61 is laminated on the first electrode 62, and is arranged for each pressure chamber 31 (for each channel) at a position facing the pressure chamber 31 with the diaphragm 32 and the first electrode 62 interposed therebetween.
  • the piezoelectric element 61 is made of a material that deforms when a voltage is applied, and is made of, for example, a ferroelectric material such as lead zirconate titanate (PZT). Further, the second electrode 63 is laminated on the surface of the piezoelectric element 61 opposite to the first electrode 62. The second electrode 63 is connected via a bump 64 to a wiring layer 51 provided on a wiring board 50 described later.
  • the film thickness of the piezoelectric element 61 is, for example, 10 ⁇ m or less.
  • the wiring board 50 has a wiring layer 51 and a silicon layer 52 on which the wiring layer 51 is formed.
  • the wiring layer 51 is connected to the bump 64 provided on the second electrode 63 via the solder 51a.
  • the outer edge of the wiring layer 51 is connected to the flexible wiring board 5.
  • a silicon layer 52 is arranged on one surface of the wiring layer 51 opposite to the drive plate 40. The silicon layer 52 is bonded to the holding unit 3.
  • the wiring board 50 is provided with a fourth communication hole 53 penetrating the wiring layer 51 and the silicon layer 52.
  • the fourth communication hole 53 communicates with the common ink chamber 2 through the third communication hole 42 of the drive plate 40 and the opening 3 a of the holding portion 3.
  • An inlet that serves as a flow path that supplies the chamber 31 is configured. The inlet plays a role of reducing the flow path resistance (flow rate) of the ink flowing from the common ink chamber 2 into the pressure chamber 31.
  • the first communication hole 21 of the intermediate plate 20 and the nozzle hole 11 of the nozzle plate 10 which are communicated with each other form an outlet for ejecting the ink in the pressure chamber 31 toward the recording medium 150.
  • the ink contained in the common ink chamber 2 passes through the inlet (that is, the fourth communication hole 53, the third communication hole 42, and the second communication hole 34), and the pressure chamber 31. Flow into. Then, by applying a voltage between the first electrode 62 and the second electrode 63, the piezoelectric element 61 is deformed (vibrated), and the diaphragm 32 is deformed (vibrated) along with the deformation of the piezoelectric element 61. .. When the vibrating plate 32 is deformed (vibrated), a pressure for ejecting ink is generated in the pressure chamber 31.
  • the ink in the pressure chamber 31 is pushed out to the outlet (that is, the first communication hole 21 and the nozzle hole 11) and is ejected from the tip (nozzle opening) of the nozzle hole 11 toward the recording medium 150. ..
  • FIG. 5 is a partially enlarged view of the region C in FIG. 3 showing the cross-sectional shape of the nozzle plate 10. Note that in FIG. 5, only the nozzle plate 10 is shown and the intermediate plate 20 is omitted for the sake of simplicity.
  • the nozzle holes 11 of the nozzle plate 10 are formed in this order from the side of the intermediate plate 20 in the ejection direction of liquid droplets (ink), and the first round portion 11a and the second round portion 11b are formed. , And the straight portion 11c.
  • the first round portion 11a is arranged on the most upstream side with respect to the ink ejection direction of the nozzle plate 10
  • the second round portion 11b is arranged on the downstream side of the first round portion 11a
  • the straight portion 11c Is arranged on the most downstream side, which is on the downstream side of the first round portion 11a.
  • the first round portion 11a is a space arranged closest to the intermediate plate 20 in the nozzle hole 11, and is a space into which the ink pushed out from the first communication hole 21 of the intermediate plate 20 first reaches and flows in. is there.
  • the first round portion 11a is a space formed by isotropic etching.
  • the first round portion 11a has an outer edge defined by an outwardly convex curved surface in the cross-sectional shape shown in FIG. 5 (that is, a cross-sectional shape along a plane parallel to the droplet ejection direction), and the first communicating hole. It has a shape in which the diameter decreases from the side of 21 to the side of the second round portion 11b (that is, toward the ink ejection direction).
  • the second round portion 11b is a space that is arranged between the first round portion 11a and the straight portion 11c and connects the first round portion 11a and the straight portion 11c.
  • the second round portion 11b is a space formed by isotropic etching under conditions different from the isotropic etching used when forming the first round portion 11a.
  • the second round portion 11b has an outer edge defined by an outwardly convex curved surface, and extends from the first round portion 11a side to the straight portion 11c side (that is, toward the ink ejection direction). ) Having a shape in which the diameter is reduced.
  • the second round portion 11b has an outer edge shape that is not similar to the outer edge shape of the first round portion 11a.
  • the straight portion 11c is a space that is arranged closest to the ejection surface of the nozzle hole 11, and the ink that has passed through the first round portion 11a and the second round portion 11b arrives and flows in the straight portion 11c of the nozzle plate 10. It is a space that is ejected to the outside (that is, the outside of the inkjet head 1).
  • the straight portion 11c is a space formed by anisotropic etching. Therefore, in the cross-sectional shape shown in FIG. 5, the straight portion 11c has a shape in which the diameter is constant from the second round portion 11b side to the ink ejection surface side (that is, toward the ink ejection direction).
  • the first round portion 11a, the second round portion 11b, and the straight portion 11c have line-symmetrical shapes with the same virtual straight line Z as the axis of symmetry.
  • the first round portion 11a, the second round portion 11b, and the straight portion 11c have a shape of n times rotational symmetry (n is an arbitrary integer) about the axis Z in the three-dimensional space.
  • the first round portion 11a has an opening portion 12a that is an opening surface that opens toward the intermediate plate 20, the first boundary portion 12b that is the boundary surface between the first round portion 11a and the second round portion 11b, and the second round portion.
  • the second boundary portion 12c which is the boundary surface between the straight portion 11c and the straight portion 11c
  • the opening portion 12d which is the opening surface of the straight portion 11c that opens toward the ink ejection surface side, are both circular and have their centers.
  • the nozzle plates 10 are arranged concentrically in a plan view so as to exist on the same axis Z.
  • the first boundary portion 12b which is the boundary surface between the first round portion 11a and the second round portion 11b, has a constricted shape in the sectional view shown in FIG. There is.
  • the first boundary portion 12b may have an apex at the intersection of the line defining the outer edge of the first round portion 11a and the line defining the outer edge of the second round portion 11b. , The intersection may have a predetermined roundness of R.
  • the diameter of the second boundary 12c and the diameter of the opening 12d are substantially the same.
  • FIG. 6 is a schematic cross-sectional view of the nozzle hole 11 shown in FIG. 5 for showing the volume of the nozzle hole 11.
  • the total cross-sectional area of the first round portion 11a and the second round portion 11b is calculated as the diameter of the opening 12a (FIG. 5).
  • Is the length of the upper side and the diameter of the second boundary portion 12c (Dc in FIG. 5) is the length of the lower side.
  • the nozzle hole 11 has a volume obtained by summing the volumes of the first round portion 11a and the second round portion 11b when the outer edges of the first round portion and the second round portion are defined by straight lines.
  • the amount of ink that can be accommodated in the nozzle holes 11 can be increased by increasing the width.
  • the edge of the first boundary portion 12b is an arbitrary one point of the edges of the second boundary portion 12c and the one point of the edges of the opening 12a that is closest to the arbitrary point. And may be outside or inside the straight line connecting the lines and (that is, the hypotenuse of the virtual trapezoid). That is, in the cross-sectional view shown in FIG. 6, the curved line indicating the side surface of the first round portion 11a and the curved surface indicating the side surface of the second round portion 11b may or may not intersect with the hypotenuse of the virtual trapezoid. Good.
  • FIG. 7 corresponds to the round portion on the upstream side (corresponding to the first round portion 11a and the second round portion 11b of the nozzle hole 11 included in the nozzle plate 10 according to the present embodiment by performing the isotropic etching only once.
  • the shape of the nozzle hole having a space formed by performing the above-mentioned isotropic etching only once is indicated by a solid line
  • the shape of the nozzle hole 11 included in the nozzle plate 10 according to the present embodiment is indicated by a dotted line.
  • FIG. 7A is a typical nozzle hole when a space 11e having the same depth as the total depth of the first round portion 11a and the second round portion 11b in the present embodiment is formed on the upstream side. It is a schematic diagram which shows a different shape. At this time, since the diameter of the opening 12e of the nozzle hole becomes larger due to side etching, it is difficult to arrange the nozzle holes at a high density.
  • FIG. 7B shows that the etching rate in the depth direction is increased by increasing the amount of sputtering by the ions generated from the etching gas by increasing the bias power, thereby increasing the depth of the first round portion 11a and the second round portion.
  • the undercut width due to side etching tends to be insufficient, and the diameter of the opening 12f of the nozzle hole cannot be increased so much, and the amount of ink that can be stored in the nozzle hole cannot be increased so much.
  • the nozzle hole 11 having the first round portion 11a and the second round portion 11b is formed by performing the isotropic etching twice, the undercut width due to the side etching is appropriately widened in the first isotropic etching. Then, the depth of the nozzle hole can be made deeper by the second isotropic etching after changing the conditions such as the bias power. Therefore, it is possible to form the nozzle hole 11 in which the diameter of the first round portion 11a is appropriately widened and the depth is sufficiently deep.
  • the second round portion 11b formed by the second isotropic etching so that the depth of the nozzle hole becomes deeper has a smaller reduction rate of the diameter in the ink ejection direction.
  • Such a second round portion 11b also has an effect similar to that of the straight portion 11c, that is, increasing the ink ejection speed and straightness. Therefore, when the nozzle hole 11 having the first round portion 11a and the second round portion 11b is formed by performing the isotropic etching twice, the ink ejection amount is increased by the first round portion 11a and the second round portion 11b.
  • the second round portion 11b and the straight portion 11c can form the nozzle hole 11 whose ejection performance is also improved.
  • the straight portion 11c is formed by anisotropic etching, the diameter of the straight portion 11c can be controlled relatively freely.
  • the nozzle hole 11 increases the amount of ink that can be accommodated in the nozzle hole 11 without changing the diameter of the straight portion 11c that affects the ink ejection characteristics, and the amount of droplets that can be ejected in one operation. Can be more.
  • Db/Da is 0.35 or more and 0.85 or less. Is preferable, and more preferably 0.5 or more and 0.7 or less. Further, Dc/Da is preferably 0.1 or more and 0.35 or less, and more preferably 0.15 or more and 0.3 or less.
  • Da is preferably 50 ⁇ m or more and 150 ⁇ m or less, and more preferably 55 ⁇ m or more and 100 ⁇ m or less.
  • Db is preferably 30 ⁇ m or more and 80 ⁇ m or less, and more preferably 35 ⁇ m or more and 70 ⁇ m or less.
  • Dc is preferably 10 ⁇ m or more and 40 ⁇ m or less, and more preferably 15 ⁇ m or more and 30 ⁇ m or less.
  • the shape of the opening 12a, the first boundary 12b, the second boundary 12c, and the opening 12d is circular, but the shape is elliptical. Other shapes such as a system may be used.
  • the shapes of the opening 12a, the first boundary portion 12b, the second boundary portion 12c, and the opening 12d are not circular, Da, Db, and Dc may have their respective short diameters.
  • La/Lb is 0.1 or more and 3 or less. It is preferably 0.2 or more and 1.5 or less. Further, Lc/(La+Lb) is preferably 0.2 or more and 2 or less, and more preferably 0.5 or more and 1.5 or less.
  • La is preferably 5 ⁇ m or more and 50 ⁇ m or less, more preferably 10 ⁇ m or more and 30 ⁇ m or less.
  • Lb is preferably 10 ⁇ m or more and 50 ⁇ m or less, and more preferably 15 ⁇ m or more and 40 ⁇ m or less.
  • Lc is preferably 10 ⁇ m or more and 50 ⁇ m or less, and more preferably 15 ⁇ m or more and 30 ⁇ m or less.
  • the first round portion 11a, the second round portion 11b, and the straight portion 11c can be manufactured by processing one silicon wafer of single crystal silicon.
  • FIGS. 8 to 11 are explanatory views showing an example of a method of manufacturing the nozzle plate 10 included in the inkjet head 1 according to this embodiment. Note that in FIGS. 8 to 11, the scales of some members are changed for easier understanding.
  • a resist is applied on a single crystal silicon wafer 710, exposed and developed to form a resist pattern 715.
  • the resist pattern 715 has a substantially circular shape that is the same as the second boundary portion 12c of the straight portion 11c at the position where the straight portion 11c of the nozzle hole 11 is formed, and the surface of the silicon wafer 710 is exposed. It may be formed so as to have the opening 715a.
  • the thickness of the resist pattern 715 may be a thickness that can withstand the subsequent first isotropic etching, second isotropic etching, and anisotropic etching, and can be selected according to each etching condition. it can.
  • the resist pattern 715 has a substantially circular shape in the present embodiment, it may have an elliptical shape or the like.
  • a first isotropic etching is performed using the resist pattern 715 as a mask.
  • the first isotropic etching can be performed, for example, by dry etching using a fluorine gas such as SF 6 as an etching gas, the flow rate of the etching gas is 200 sccm, the pressure is 10 Pa, and the bias power is 10 W. ..
  • a fluorine gas such as SF 6 as an etching gas
  • the flow rate of the etching gas is 200 sccm
  • the pressure is 10 Pa
  • the bias power is 10 W. ..
  • FIG. 8B in the cross section obtained by cutting the silicon wafer 710 in the thickness direction by the first isotropic etching, the first round having a curved side surface shape and a reduced diameter in the depth direction.
  • Pattern 711a is formed.
  • the maximum width of the first round pattern 711a is wider than the width of the opening 715a of the resist pattern 715.
  • second isotropic etching is performed under conditions different from those of the first isotropic etching.
  • the second isotropic etching may be performed under the condition that the etching rate in the depth direction is higher than that of the first isotropic etching.
  • the condition that the bias power is larger than that of the first isotropic etching is used. You can go in.
  • the second isotropic etching can be performed, for example, by dry etching using a fluorine gas such as SF 6 as an etching gas, the flow rate of the etching gas is 200 sccm, the pressure is 10 Pa, and the bias power is 60 W. ..
  • the etching conditions for the first isotropic etching and the second isotropic etching are set so as to control the shape formed mainly by changing the bias power.
  • the range of the bias power is preferably 10 W to 30 W in the first isotropic etching and 50 W to 80 W in the second isotropic etching.
  • the shape of the etching gas species can be better controlled by adding another fluorine-based composition or oxygen.
  • the ICP power to be applied is preferably in the range of 1000 to 2000W.
  • anisotropic etching is performed using the resist pattern 715 as a mask.
  • the above-mentioned anisotropic etching may be repeated by switching the mode from the isotropic etching to the anisotropic etching using an apparatus having a function corresponding to the anisotropic etching commonly called Bosch process.
  • the anisotropic etching is performed by using, for example, a fluorine-based gas such as SF 6 as an etching gas and C 4 F 8 as a passivation gas.
  • Dry etching can be performed with an etching gas flow rate of 500 sccm, a passivation gas flow rate of 600 sccm, a pressure of 10 Pa, and a bias power of 60 W.
  • a straight pattern 711c having a straight side surface shape and a constant diameter in the depth direction is formed. It is formed.
  • the width of the straight pattern 711c is substantially the same as the width of the opening 715a of the resist pattern 715.
  • the resist (resist pattern 715) is removed.
  • a photosensitive material 716 a such as a positive resist or photosensitive polyimide is applied to the surface of the silicon wafer 710.
  • the photosensitive material is applied by a low-speed coater or the silicon wafer 710 is dipped in the photosensitive material so that the applied photosensitive material 716a is sufficiently introduced into the straight pattern 711c. You can do it.
  • the photosensitive material 716a is exposed and cured using a photomask 1010 having a width larger than the width of the straight pattern 711c.
  • the photosensitive material 716a can be cured so that at least the inside of the straight pattern 711c is filled with the cured material 716b (protective material) of the photosensitive material.
  • a protective film 717 is attached to the silicon wafer 710 so as to cover the opening of the first round pattern 711a, and the silicon wafer 710 is turned upside down.
  • the protective film 717 may cover the opening of the first round-shaped pattern 711a so as to prevent the cured material 716b of the photosensitive material from falling off when the silicon wafer 710 is turned upside down,
  • a silicon wafer, a SiC wafer, a glass plate, or the like can be used.
  • the silicon wafer 710 is ground from the surface opposite to the surface on which the first round pattern 711a to the straight pattern 711c are formed. The grinding is performed at least until the straight pattern 711c and the cured material 716b of the photosensitive material are exposed. After that, the ground surface is mirror-finished by polishing.
  • a liquid repellent film 713 is formed on the polished and mirror-finished surface.
  • the liquid repellent film 713 may have any liquid repellent property with respect to the ink, and for example, a solution containing a liquid repellent agent such as fluorine may be applied and baked.
  • a solution containing a liquid repellent agent such as fluorine
  • the protective film 717 is removed, and the cured material 716a of the photosensitive material is also removed.
  • the liquid repellent film 713 deposited on the surface of the cured material 716b of the photosensitive material is also lifted off and simultaneously removed.
  • the nozzle plate 10 can be obtained by removing contaminants by O 2 plasma or the like, cleaning with a cleaning liquid or the like, and then cutting the silicon wafer 710 into a desired shape for individualization.
  • the nozzle plate 10 thus obtained is joined to the separately prepared intermediate plate 20, and further joined to the pressure chamber forming plate 30, the drive plate 40, and the wiring substrate 50 to form the head chip 4. be able to. Furthermore, the ink jet head 1 can be obtained by joining the head chip 4 to the common ink chamber 2, the holding portion 3, and the flexible wiring board 5. The inkjet head 1 can be mounted on an image forming apparatus using a known inkjet method.
  • the piezo type inkjet head having the piezoelectric element is used for description, but the nozzle plate having the nozzle plate may be applied to another type of inkjet head such as a thermal jet type. Good.
  • the nozzle plate of the present invention it is possible to increase the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of droplets from the inkjet head. Therefore, according to the nozzle plate of the present invention, it is possible to further increase the definition of the image to be formed and to form the image more efficiently, and thus contribute to the further spread of the inkjet head in the fields such as image formation and pattern formation. There is expected.

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Abstract

The present invention relates to a nozzle plate having a plurality of nozzle holes for discharging droplets. In the nozzle plate, the nozzle hole has a first round portion that is disposed on the most upstream side with respect to the droplet ejection direction and has a diameter decreasing in the droplet ejection direction; a second round portion that is disposed downstream of the first round portion and has a diameter decreasing in the droplet ejection direction; and a straight portion that is disposed downstream of the second round portion and has a constant diameter in the droplet ejection direction. In the cross-sectional shape along a plane parallel to the droplet ejection direction, each of the first round portion and the second round portion has a shape in which the outer edge is defined by an outwardly convex curved surface, and a boundary between the outer edge of the first round portion and the outer edge of the second round portion is convex inward.

Description

ノズルプレートおよびその製造方法、インクジェットヘッド、ならびに画像形成装置Nozzle plate and method of manufacturing the same, inkjet head, and image forming apparatus
　本発明は、ノズルプレートおよびその製造方法、インクジェットヘッド、ならびに画像形成装置に関する。 The present invention relates to a nozzle plate, a method for manufacturing the nozzle plate, an inkjet head, and an image forming apparatus.
　インクジェットプリンタ等に用いられるインクジェットヘッドは、液滴（インク）の吐出面に、多数の微小なノズル孔を備えたノズルプレートを有する。 An inkjet head used in an inkjet printer or the like has a nozzle plate provided with a large number of minute nozzle holes on the ejection surface of droplets (ink).
　ノズルプレートには、液滴の吐出特性を制御しつつ、１回の動作で吐出できる液滴量を多くするため、それぞれのノズル孔の液滴を吐出する側の開口面積をより小さくしつつ、ノズル孔の体積をより大きくすることが求められる。 In the nozzle plate, in order to increase the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of the droplets, the opening area of each nozzle hole on the ejection side is made smaller, It is required to increase the volume of the nozzle hole.
　たとえば、特許文献１～特許文献４には、液体の流入側から液体の吐出側にかけて、曲線状に流路幅が狭くなるような、逆ラウンド形状のノズル孔を有するノズルプレートが記載されている。このような形状のノズル孔は、液滴を吐出する側の開口面積を小さくしつつ、ノズル孔の体積をより大きくすることができると考えられる。 For example, Patent Documents 1 to 4 describe a nozzle plate having a reverse round-shaped nozzle hole in which a flow path width is curvilinearly narrowed from a liquid inflow side to a liquid discharge side. .. It is considered that the nozzle hole having such a shape can increase the volume of the nozzle hole while reducing the opening area on the side where droplets are ejected.
　また、特許文献４および特許文献５には、液体の吐出方向に沿って断面形状が段階的に変化するノズル孔を有するノズルプレートが記載されている。 Further, Patent Documents 4 and 5 describe nozzle plates having nozzle holes whose cross-sectional shape changes stepwise along the liquid ejection direction.
　特許文献４では、ＳＯＩ（Silicon  on  Insulator）ウェハが有する第１のシリコン層を異方性エッチングして液滴を吐出する側の略垂直な空間を形成し、上記ＳＯＩウェハが有する第２のシリコン層を等方性エッチングして上記略垂直な空間に接続する曲線状に流路幅が狭くなるような空間を形成し、その後、液体を導入する略垂直な空間を形成したガラス基板を陽極接合することによって、断面形状が異なる３つの空間がノズル孔の内部に形成されたノズルプレートを作製している。 In Patent Document 4, the first silicon layer of an SOI (Silicon on Insulator) wafer is anisotropically etched to form a substantially vertical space on the side where droplets are discharged, and the second silicon of the SOI wafer is formed. Isotropic etching is performed on the layer to form a curved space that connects the above-mentioned substantially vertical space with a narrow channel width, and then a glass substrate having a substantially vertical space into which liquid is introduced is anodically bonded. By doing so, a nozzle plate in which three spaces having different cross-sectional shapes are formed inside the nozzle hole is manufactured.
　特許文献５では、ドリル加工およびプレス加工により形成された、テーパ角が異なる２段のテーパ穴部を有するノズルプレートを作製している。　 In Patent Document 5, a nozzle plate having two steps of tapered holes having different taper angles formed by drilling and pressing is manufactured. ‥
特開２０１４－０５４７８８号公報JP, 2014-054788, A 特開２００９－１１３３６３号公報JP, 2009-113363, A 特開２００８－０８７２８４号公報JP, 2008-087284, A 特開２００８－１５５５９１号公報JP, 2008-155591, A 特開２００５－３０５８８３号公報JP 2005-305883 A
　特許文献１～特許文献５に記載のように、インクジェットヘッドのノズルプレートが有するノズル孔には様々な形状が検討されており、それぞれの形状のノズル孔を形成するための加工方法も検討されている。 As described in Patent Documents 1 to 5, various shapes have been studied for the nozzle holes of the nozzle plate of the inkjet head, and a processing method for forming the nozzle holes of each shape has also been studied. There is.
　しかし、液滴の吐出特性を制御しつつ、１回の動作で吐出できる液滴量を多くできるような形状のノズル孔を有するノズルプレート、および当該形状のノズル孔を形成するための加工方法を開発することへの要望は依然として存在する。 However, a nozzle plate having a nozzle hole having a shape capable of increasing the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of the droplet, and a processing method for forming the nozzle hole having the shape are provided. The desire to develop still exists.
　本発明は、上記知見に基づいてなされたものであり、液滴の吐出特性を制御しつつ、１回の動作で吐出できる液滴量を多くできるような形状のノズル孔を有するノズルプレートおよびその製造方法、当該ノズルプレートを備えるインクジェットヘッド、ならびに当該インクジェットヘッドを備える画像形成装置を提供することを、その目的とする。 The present invention has been made based on the above findings, and a nozzle plate having a nozzle hole having a shape capable of increasing the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of the droplets, and the same. An object of the present invention is to provide a manufacturing method, an inkjet head including the nozzle plate, and an image forming apparatus including the inkjet head.
　上記課題は、液滴を吐出するための複数のノズル孔を有するノズルプレートであって、上記ノズル孔は、上記液滴の吐出方向に対して最も上流側に配置され、かつ上記液滴の吐出方向に向かって径が縮小する第１ラウンド部と、上記第１ラウンド部よりも下流側に配置され、かつ上記液滴の吐出方向に向かって径が縮小する第２ラウンド部と、上記第２ラウンド部よりも下流側に配置され、かつ上記液滴の吐出方向に向かって径が一定であるストレート部と、を有し、上記液滴の吐出方向に平行な平面に沿った断面形状において、上記第１ラウンド部および上記第２ラウンド部は、いずれも、外側に凸の曲面によって外縁が規定された形状を有し、かつ、上記第１ラウンド部の外縁と上記第２ラウンド部の外縁との境界部は、内側に凸となっている、ノズルプレートによって解決される。 The above problem is a nozzle plate having a plurality of nozzle holes for ejecting droplets, wherein the nozzle holes are arranged on the most upstream side in the ejection direction of the droplets, and A first round portion whose diameter decreases in a direction, a second round portion which is arranged on the downstream side of the first round portion and whose diameter decreases in the droplet ejection direction, and the second round portion In a cross-sectional shape along a plane parallel to the discharge direction of the droplet, the straight portion having a diameter that is arranged downstream of the round portion and has a constant diameter in the discharge direction of the droplet, Each of the first round portion and the second round portion has a shape in which an outer edge is defined by a curved surface that is convex outward, and an outer edge of the first round portion and an outer edge of the second round portion. The boundary of is solved by the nozzle plate, which is convex inward.
　また、上記課題は、その一の表面にレジストパターンを形成した単結晶シリコンウエハを、上記レジストパターンをマスクとして等方性エッチングする第１の等方性エッチング工程と、上記単結晶シリコンウエハを、上記レジストパターンをマスクとして、上記第１の等方性エッチング工程とは異なる条件で等方性エッチングする第２の等方性エッチング工程と上記単結晶シリコンウエハを、上記レジストパターンをマスクとして、異方性エッチングする異方性エッチング工程と、をこの順で含む、ノズルプレートの製造方法によって解決される。 Further, the above-mentioned problem is that a single crystal silicon wafer having a resist pattern formed on one surface thereof is subjected to a first isotropic etching step of performing isotropic etching using the resist pattern as a mask, and the single crystal silicon wafer is Using the resist pattern as a mask, a second isotropic etching step of performing isotropic etching under different conditions from the first isotropic etching step and the single crystal silicon wafer are performed using the resist pattern as a mask. This is solved by a method for manufacturing a nozzle plate, which includes an anisotropic etching step of performing isotropic etching in this order.
　また、上記課題は、上記ノズルプレートを有するインクジェットヘッドによって解決される。 Also, the above problems can be solved by an inkjet head having the above nozzle plate.
　また、上記課題は、上記インクジェットヘッドを有する画像形成装置によって解決される。 Further, the above problems can be solved by an image forming apparatus having the above inkjet head.
　本発明により、隔壁のアスペクト比がより大きい圧力室を有し、かつ作製時の破壊が生じにくいインクジェットヘッドおよびその製造方法、ならびに当該インクジェットヘッドを備える画像形成装置が提供される。 According to the present invention, an inkjet head having a pressure chamber with a larger aspect ratio of partition walls and less likely to be destroyed during manufacturing, a method for manufacturing the inkjet head, and an image forming apparatus including the inkjet head are provided.
図１は、インクジェット法による画像形成装置の構成を示す模式図である。FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus using an inkjet method. 図２は、図１に示す画像形成装置に用いられる、本発明の実施形態におけるインクジェットヘッドの概要を示す分解斜視図である。FIG. 2 is an exploded perspective view showing an outline of an inkjet head used in the image forming apparatus shown in FIG. 1 in the embodiment of the present invention. 図３は、本発明の実施形態におけるインクジェットヘッドが有するヘッドチップの概要を示す、図２における線Ａ－Ａに沿った断面図である。FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, showing an outline of a head chip included in the inkjet head according to the embodiment of the present invention. 図４は、本発明の実施形態におけるインクジェットヘッドが有するヘッドチップの概要を示す、図２における線Ｂ－Ｂに沿った断面図である。FIG. 4 is a cross-sectional view taken along line BB in FIG. 2, showing an outline of a head chip included in the inkjet head according to the embodiment of the present invention. 図５は、本発明の実施形態におけるインクジェットヘッドが有するノズルプレートの断面形状を示す、図３における領域Ｃの部分拡大図である。FIG. 5 is a partially enlarged view of a region C in FIG. 3, showing a cross-sectional shape of the nozzle plate included in the inkjet head according to the embodiment of the present invention. 図６は、図５に示したノズルプレートが有するノズル孔の容積を示すための、当該ノズル孔の模式断面図である。FIG. 6 is a schematic cross-sectional view of the nozzle hole for showing the volume of the nozzle hole included in the nozzle plate shown in FIG. 図７Ａは、等方性エッチングを１回のみ行うことにより上流側のラウンド部を作製したときの、ノズル孔の形状を示す断面図であり、図７Ｂは、等方性エッチングを１回のみ行うことにより上流側のラウンド部を作製したときの、ノズル孔の別の形状を示す断面図である。FIG. 7A is a cross-sectional view showing the shape of a nozzle hole when an upstream round portion is produced by performing isotropic etching only once, and FIG. 7B is isotropic etching performed only once. It is sectional drawing which shows another shape of a nozzle hole at the time of producing the round part by the side of this. 図８Ａ～図８Ｃは、本発明の実施形態におけるノズルプレートを製造する工程を示す第１の工程図である。8A to 8C are first process diagrams showing a process of manufacturing the nozzle plate according to the embodiment of the present invention. 図９Ａ～図９Ｃは、本発明の実施形態におけるノズルプレートを製造する工程を示す第２の工程図である。9A to 9C are second process charts showing the process of manufacturing the nozzle plate according to the embodiment of the present invention. 図１０Ａ～図１０Ｂは、本発明の実施形態におけるノズルプレートを製造する工程を示す第３の工程図である。10A to 10B are third process charts showing the process of manufacturing the nozzle plate in the embodiment of the present invention. 図１１Ａ～図１１Ｃは、本発明の実施形態におけるノズルプレートを製造する工程を示す第４の工程図である。11A to 11C are fourth process charts showing the process of manufacturing the nozzle plate according to the embodiment of the present invention.
　以下、本発明の実施形態について図面を参照して詳細に説明する。なお、各図において共通の部材には、同一の符号を付している。また、本発明は、以下の形態に限定されるものではない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, common members are designated by the same reference numerals. Moreover, the present invention is not limited to the following modes.
　［画像形成装置およびインクジェットヘッド］
　本発明の第１の実施形態における画像形成装置は、後述の本実施形態に係るインクジェットヘッドを有する以外は公知のインクジェット法による画像形成装置と同様の構成とすることができる。 [Image forming apparatus and inkjet head]
The image forming apparatus according to the first embodiment of the present invention can have the same configuration as the image forming apparatus by a known inkjet method except that the image forming apparatus according to the present embodiment has an inkjet head according to the present embodiment described below.
　画像形成装置１００は、図１に示すように、インクジェットヘッド１と、インク供給装置１２０と、搬送装置１３０と、メインタンク１４０とを有している。 As shown in FIG. 1, the image forming apparatus 100 includes an inkjet head 1, an ink supply device 120, a transport device 130, and a main tank 140.
　インクジェットヘッド１は、インク滴を被印刷物である用紙などの記録媒体１５０に吐出するための複数のノズルを有する。たとえば、インクジェットヘッド１は、色の異なる複数種のインクがそれぞれ特定のノズルに供給されるように構成される。インクジェットヘッド１は、たとえば、画像を形成すべき記録媒体１５０の搬送方向Ｘを横切る方向に走査自在に配置されている。インクジェットヘッド１の構成については後述する。 The inkjet head 1 has a plurality of nozzles for ejecting ink droplets onto a recording medium 150 such as paper, which is a printing target. For example, the inkjet head 1 is configured such that a plurality of types of ink having different colors are supplied to specific nozzles. The inkjet head 1 is, for example, arranged so as to be capable of scanning in a direction transverse to the transport direction X of the recording medium 150 on which an image is to be formed. The configuration of the inkjet head 1 will be described later.
　搬送装置１３０は、インクジェットヘッド１に対して記録媒体１５０を搬送するための装置である。搬送装置１３０は、たとえば、ベルトコンベア１３１と、回転自在な送りローラー１３２とを備える。ベルトコンベア１３１は、回転自在なプーリー１３３ａ、１３３ｂと、これらのプーリー１３３ａ、１３３ｂに張設されている無端状のベルト１３４と、から構成される。送りローラー１３２は、記録媒体１５０の搬送方向Ｘにおける上流側のプーリー１３３ａに対向する位置に、ベルト１３４と記録媒体１５０を挟持してベルト１３４上に記録媒体１５０を送り出すように配置されている。 The transport device 130 is a device for transporting the recording medium 150 to the inkjet head 1. The transport device 130 includes, for example, a belt conveyor 131 and a rotatable feed roller 132. The belt conveyor 131 is composed of rotatable pulleys 133a and 133b, and an endless belt 134 stretched around these pulleys 133a and 133b. The feed roller 132 is arranged at a position facing the pulley 133a on the upstream side in the transport direction X of the recording medium 150 so as to sandwich the belt 134 and the recording medium 150 and feed the recording medium 150 onto the belt 134.
　インク供給装置１２０は、インクジェットヘッド１と一体的に配置されている。インク供給装置１２０は、インクの種類ごとに配置されている。たとえば、Ｙ（イエロー）、Ｍ（マゼンタ）、Ｃ（シアン）およびＫ（ブラック）の４色のインクを用いるときは、インク供給装置１２０は、インクジェットヘッド１に四つ配置される。 The ink supply device 120 is arranged integrally with the inkjet head 1. The ink supply device 120 is arranged for each type of ink. For example, when four color inks of Y (yellow), M (magenta), C (cyan) and K (black) are used, four ink supply devices 120 are arranged in the inkjet head 1.
　各インク供給装置１２０は、メインタンク１４０に接続された管１６１および弁１６４を介して、メインタンク１４０内のインクを供給される。また、各インク供給装置１２０は、管１６２を介してインクジェットヘッド１の後述する共通インク室２と連通し、各色のインクを所望の共通インク室２のインク供給口２ａへ供給可能に接続されている。 Each ink supply device 120 is supplied with ink in the main tank 140 via a pipe 161 and a valve 164 connected to the main tank 140. Further, each ink supply device 120 communicates with a common ink chamber 2 of the inkjet head 1 described later via a pipe 162, and is connected so as to be able to supply ink of each color to an ink supply port 2 a of a desired common ink chamber 2. There is.
　インクジェットヘッド１は、上記の管１６１から分岐するバイパス管１６３によってメインタンク１４０にも接続されている。管１６１とバイパス管１６３との分岐点には、これら管１６１およびバイパス管１６３の一方または両方にインクの流路を切換、設定可能な弁１６４が配置されている。管１６１、管１６２、およびバイパス管１６３は、たとえばいずれも可撓性を有するチューブである。弁１６４は、たとえば三方弁である。 The inkjet head 1 is also connected to the main tank 140 by a bypass pipe 163 branched from the pipe 161. At a branch point between the pipe 161 and the bypass pipe 163, a valve 164 that can switch and set a flow path of ink to one or both of the pipe 161 and the bypass pipe 163 is arranged. Each of the pipe 161, the pipe 162, and the bypass pipe 163 is a flexible tube. The valve 164 is, for example, a three-way valve.
　メインタンク１４０は、インクジェットヘッド１に供給されるべきインクを収容するためのタンクである。メインタンク１４０は、インクジェットヘッド１とは分離して配置されている。メインタンク１４０は、たとえば、不図示の撹拌装置を有している。メインタンク１４０は、画像形成装置１００の画像形成性能や大きさなどに応じて適宜に決めることが可能である。たとえば、画像形成装置の画像形成速度が１～３ｍ２／分である場合、メインタンク１４０の容量は、たとえば１Ｌである。 The main tank 140 is a tank for containing the ink to be supplied to the inkjet head 1. The main tank 140 is arranged separately from the inkjet head 1. The main tank 140 has, for example, a stirring device (not shown). The main tank 140 can be appropriately determined according to the image forming performance and size of the image forming apparatus 100. For example, when the image forming speed of the image forming apparatus is 1 to 3 m 2 /min, the capacity of the main tank 140 is, for example, 1 L.
　図２は、上述した画像形成装置１００に用いられるインクジェットヘッド１の概要を示す分解斜視図である。図２に示すように、インクジェットヘッド１は、共通インク室２と、保持部３と、ヘッドチップ４と、フレキシブル配線基板５と、を有している。 FIG. 2 is an exploded perspective view showing an outline of the inkjet head 1 used in the image forming apparatus 100 described above. As shown in FIG. 2, the inkjet head 1 has a common ink chamber 2, a holding portion 3, a head chip 4, and a flexible wiring board 5.
　共通インク室２は、中空の略直方体状に形成されており、保持部３と対向する一面が開口している。共通インク室２の上記開口と対向する一面には、インク供給装置１２０のインクを供給するためのインク供給口２ａと、インクをインク供給装置１２０に排出するためのインク排出口２ｂが設けられている。共通インク室２は、内部にフィルタを備え、上記フィルタによりインク供給口２ａから供給されたインクから異物を取り除くと共に、インク内に含有される気泡を細かく破砕する。 The common ink chamber 2 is formed in a hollow, substantially rectangular parallelepiped shape, and one surface facing the holding portion 3 is open. An ink supply port 2a for supplying the ink of the ink supply device 120 and an ink discharge port 2b for discharging the ink to the ink supply device 120 are provided on one surface of the common ink chamber 2 facing the opening. There is. The common ink chamber 2 has a filter inside, and removes foreign matters from the ink supplied from the ink supply port 2a by the filter and finely crushes the bubbles contained in the ink.
　保持部３は、略中央に開口部３ａを有する略平板状に形成されており、共通インク室２の上記開口を覆うように配置されている。これにより、保持部３の一方の面には、開口部３ａを覆うようにして共通インク室２が接続される。また、保持部３の他方の面には、開口部３ａを覆うようにしてヘッドチップ４が接続される。保持部３は、開口部３ａを介して、共通インク室２とヘッドチップ４とを連通させる。 The holding portion 3 is formed in a substantially flat plate shape having an opening 3a at a substantially center thereof, and is arranged so as to cover the opening of the common ink chamber 2. As a result, the common ink chamber 2 is connected to one surface of the holding portion 3 so as to cover the opening 3a. The head chip 4 is connected to the other surface of the holding portion 3 so as to cover the opening 3a. The holding unit 3 connects the common ink chamber 2 and the head chip 4 via the opening 3a.
　保持部３の外周部には、挿通孔３ｂが設けられている。挿通孔３ｂには、フレキシブル配線基板５が挿通される。フレキシブル配線基板５は、その一方の端部が、後述するヘッドチップ４の配線基板５０に接続される。また、フレキシブル配線基板５は、その他方の端部が、保持部３に設けた挿通孔３ｂを保持部３の他方の面から挿通して、共通インク室２側に引き出される。 An insertion hole 3b is provided on the outer peripheral portion of the holding portion 3. The flexible wiring board 5 is inserted into the insertion hole 3b. One end of the flexible wiring board 5 is connected to the wiring board 50 of the head chip 4 described later. The other end of the flexible wiring board 5 is inserted into the insertion hole 3b provided in the holding portion 3 from the other surface of the holding portion 3 and is drawn out to the common ink chamber 2 side.
　図３は、上述したインクジェットヘッド１が有するヘッドチップ４の概要を示す、図２における線Ａ－Ａに沿った断面図であり、図４は、上述したインクジェットヘッド１が有するヘッドチップ４の概要を示す、図２における線Ｂ－Ｂに沿った断面図である。 FIG. 3 is a cross-sectional view taken along line AA in FIG. 2 showing an outline of the head chip 4 included in the inkjet head 1 described above, and FIG. 4 is an outline of the head chip 4 included in the inkjet head 1 described above. FIG. 3 is a sectional view taken along line BB in FIG.
　ヘッドチップ４は、ノズルプレート１０と、中間プレート２０と、圧力室形成プレート３０と、駆動プレート４０と、配線基板５０とを有している。また、ヘッドチップ４は、インクの吐出面側から、ノズルプレート１０、中間プレート２０、圧力室形成プレート３０、駆動プレート４０、配線基板５０の順に積層されている。 The head chip 4 has a nozzle plate 10, an intermediate plate 20, a pressure chamber forming plate 30, a drive plate 40, and a wiring board 50. Further, the head chip 4 is formed by laminating a nozzle plate 10, an intermediate plate 20, a pressure chamber forming plate 30, a drive plate 40, and a wiring board 50 in this order from the ink ejection surface side.
　ノズルプレート１０には、複数のノズル孔１１が形成されている。ノズル孔１１は、ノズルプレート１０の一面から他面にかけて貫通している。このノズル孔１１は、吐出口となる先端側が小径となるように絞り込まれた断面形状を有し、共通インク室２から供給されたインクを吐出口から外部に吐出する。また、ノズル孔１１は、ノズルプレート１０に複数（たとえば、５００～２０００個）設けられ、マトリックス状に配置されている。このノズル孔１１は、ノズルプレート１０に積層される中間プレート２０を介して圧力室形成プレート３０に形成された圧力室３１と連通する。 A plurality of nozzle holes 11 are formed in the nozzle plate 10. The nozzle hole 11 penetrates from one surface of the nozzle plate 10 to the other surface. The nozzle hole 11 has a cross-sectional shape that is narrowed down so that the tip side, which is an ejection port, has a small diameter, and ejects the ink supplied from the common ink chamber 2 from the ejection port to the outside. A plurality of nozzle holes 11 (for example, 500 to 2000) are provided in the nozzle plate 10 and are arranged in a matrix. The nozzle hole 11 communicates with the pressure chamber 31 formed in the pressure chamber forming plate 30 via the intermediate plate 20 laminated on the nozzle plate 10.
　ノズルプレート１０のインク吐出側の表面には、撥液膜１３が形成されている。 A liquid repellent film 13 is formed on the surface of the nozzle plate 10 on the ink ejection side.
　中間プレート２０は、ノズルプレート１０と、圧力室形成プレート３０との間に配置される。中間プレート２０には、ノズル孔１１と後述する圧力室形成プレート３０に設けた圧力室３１とを連通する第１連通孔２１が設けられている。この第１連通孔２１は、ノズルプレート１０のノズル孔１１と対応する位置に設けられ、中間プレート２０の一面から他面にかけて貫通している。 The intermediate plate 20 is arranged between the nozzle plate 10 and the pressure chamber forming plate 30. The intermediate plate 20 is provided with a first communication hole 21 that connects the nozzle hole 11 and a pressure chamber 31 provided in the pressure chamber forming plate 30 described later. The first communication hole 21 is provided at a position corresponding to the nozzle hole 11 of the nozzle plate 10, and penetrates from one surface to the other surface of the intermediate plate 20.
　圧力室形成プレート３０は、複数の圧力室３１と、振動板３２とを有している。圧力室３１は、ノズルプレート１０のノズル孔１１および中間プレート２０の第１連通孔２１と対応する位置に設けられている。また、圧力室３１は、圧力室形成プレート３０の一面から他面にかけて貫通している。圧力室３１は、その体積変動によって、ノズル孔１１から吐出されるインクに吐出圧力を付与する。また、複数の圧力室３１の間には、隔壁３３が形成されている。本実施形態において、隔壁３３は、その全体がニッケル（Ｎｉ）などの電気メッキが可能な金属によって形成されている。これにより、隔壁３３の剛性をより高くして、インクジェットヘッド１を振動によって破壊されにくく安定した構造とすることができる。 The pressure chamber forming plate 30 has a plurality of pressure chambers 31 and a vibration plate 32. The pressure chamber 31 is provided at a position corresponding to the nozzle hole 11 of the nozzle plate 10 and the first communication hole 21 of the intermediate plate 20. Further, the pressure chamber 31 penetrates from one surface to the other surface of the pressure chamber forming plate 30. The pressure chamber 31 applies an ejection pressure to the ink ejected from the nozzle hole 11 due to its volume variation. A partition 33 is formed between the plurality of pressure chambers 31. In the present embodiment, the partition 33 is entirely formed of an electroplatable metal such as nickel (Ni). As a result, the rigidity of the partition wall 33 can be made higher, and the inkjet head 1 can have a stable structure that is not easily destroyed by vibration.
　振動板３２は、圧力室３１が有する中間プレート２０とは反対側の開口を覆うように配置されている。振動板３２には、圧力室３１と連通する第２連通孔３４が設けられている。振動板３２における圧力室３１側の一面と反対側の一面には、駆動プレート４０が配置されている。 The diaphragm 32 is arranged so as to cover the opening of the pressure chamber 31 opposite to the intermediate plate 20. The diaphragm 32 is provided with a second communication hole 34 that communicates with the pressure chamber 31. The drive plate 40 is arranged on one surface of the vibration plate 32 opposite to the one surface on the pressure chamber 31 side.
　駆動プレート４０は、空間部４１と、第２連通孔３４と連通する第３連通孔４２とを有している。空間部４１は、振動板３２を間に挟んで圧力室３１と対向する位置に配置されている。空間部４１には、アクチュエータ６０が収容されている。 The drive plate 40 has a space 41 and a third communication hole 42 that communicates with the second communication hole 34. The space 41 is arranged at a position facing the pressure chamber 31 with the diaphragm 32 interposed therebetween. The actuator 60 is housed in the space 41.
　アクチュエータ６０は、圧電素子６１と、第１電極６２と、第２電極６３とを有している。第１電極６２は、振動板３２の一面に積層されている。なお、第１電極６２と振動板３２との間には、絶縁層が配置されていてもよい。圧電素子６１は、第１電極６２に積層されて、振動板３２および第１電極６２を間に挟んで圧力室３１と対向する位置に、圧力室３１毎（チャネル毎）に配置される。 The actuator 60 has a piezoelectric element 61, a first electrode 62, and a second electrode 63. The first electrode 62 is laminated on one surface of the diaphragm 32. An insulating layer may be arranged between the first electrode 62 and the diaphragm 32. The piezoelectric element 61 is laminated on the first electrode 62, and is arranged for each pressure chamber 31 (for each channel) at a position facing the pressure chamber 31 with the diaphragm 32 and the first electrode 62 interposed therebetween.
　圧電素子６１は、電圧が印加されることによって変形する材料で構成されており、たとえば、チタン酸ジルコン酸鉛（ＰＺＴ）などの強誘電体材料で構成されている。また、圧電素子６１における第１電極６２とは反対側の面には、第２電極６３が積層されている。第２電極６３は、バンプ６４を介して後述する配線基板５０に設けられた配線層５１と接続される。圧電素子６１の膜厚は、たとえば１０μｍ以下である。 The piezoelectric element 61 is made of a material that deforms when a voltage is applied, and is made of, for example, a ferroelectric material such as lead zirconate titanate (PZT). Further, the second electrode 63 is laminated on the surface of the piezoelectric element 61 opposite to the first electrode 62. The second electrode 63 is connected via a bump 64 to a wiring layer 51 provided on a wiring board 50 described later. The film thickness of the piezoelectric element 61 is, for example, 10 μm or less.
　配線基板５０は、配線層５１と、配線層５１が一面に形成されたシリコン層５２とを有している。配線層５１は、第２電極６３に設けたバンプ６４と、半田５１ａを介して接続される。また、配線層５１の外縁部は、フレキシブル配線基板５に接続される。さらに、配線層５１における駆動プレート４０と反対側の一面には、シリコン層５２が配置される。シリコン層５２は、保持部３に接合される。 The wiring board 50 has a wiring layer 51 and a silicon layer 52 on which the wiring layer 51 is formed. The wiring layer 51 is connected to the bump 64 provided on the second electrode 63 via the solder 51a. The outer edge of the wiring layer 51 is connected to the flexible wiring board 5. Further, a silicon layer 52 is arranged on one surface of the wiring layer 51 opposite to the drive plate 40. The silicon layer 52 is bonded to the holding unit 3.
　また、配線基板５０には、配線層５１およびシリコン層５２を貫通する第４連通孔５３が設けられている。この第４連通孔５３は、駆動プレート４０の第３連通孔４２と、保持部３の開口部３ａを介して共通インク室２と連通する。 Further, the wiring board 50 is provided with a fourth communication hole 53 penetrating the wiring layer 51 and the silicon layer 52. The fourth communication hole 53 communicates with the common ink chamber 2 through the third communication hole 42 of the drive plate 40 and the opening 3 a of the holding portion 3.
　本実施形態では、互いに連通された配線基板５０の第４連通孔５３、駆動プレート４０の第３連通孔４２、および振動板３２の第２連通孔３４により、共通インク室２内のインクを圧力室３１に供給する流路となるインレットが構成される。インレットは、共通インク室２から圧力室３１に流入されるインクの流路抵抗（流量）を絞る役割を担う。また、互いに連通された中間プレート２０の第１連通孔２１およびノズルプレート１０のノズル孔１１により、圧力室３１内のインクを記録媒体１５０に向けて吐出するためのアウトレットが構成される。 In the present embodiment, the fourth communication hole 53 of the wiring board 50, the third communication hole 42 of the drive plate 40, and the second communication hole 34 of the vibration plate 32, which are in communication with each other, pressurize the ink in the common ink chamber 2. An inlet that serves as a flow path that supplies the chamber 31 is configured. The inlet plays a role of reducing the flow path resistance (flow rate) of the ink flowing from the common ink chamber 2 into the pressure chamber 31. Further, the first communication hole 21 of the intermediate plate 20 and the nozzle hole 11 of the nozzle plate 10 which are communicated with each other form an outlet for ejecting the ink in the pressure chamber 31 toward the recording medium 150.
　かかる構成を備えたインクジェットヘッド１では、共通インク室２に収容されたインクは、インレット（すなわち第４連通孔５３、第３連通孔４２および第２連通孔３４）を通過して、圧力室３１に流れ込む。そして、第１電極６２と第２電極６３との間に電圧が印加されることで、圧電素子６１が変形（振動）すると共に圧電素子６１の変形に伴い、振動板３２が変形（振動）する。この振動板３２が変形（振動）することで、圧力室３１内にインクを吐出するための圧力が発生する。かかる圧力の発生により、圧力室３１内のインクは、アウトレット（すなわち第１連通孔２１およびノズル孔１１）に押し出され、ノズル孔１１の先端（ノズル開口）から記録媒体１５０に向けて吐出される。 In the inkjet head 1 having such a configuration, the ink contained in the common ink chamber 2 passes through the inlet (that is, the fourth communication hole 53, the third communication hole 42, and the second communication hole 34), and the pressure chamber 31. Flow into. Then, by applying a voltage between the first electrode 62 and the second electrode 63, the piezoelectric element 61 is deformed (vibrated), and the diaphragm 32 is deformed (vibrated) along with the deformation of the piezoelectric element 61. .. When the vibrating plate 32 is deformed (vibrated), a pressure for ejecting ink is generated in the pressure chamber 31. Due to the generation of the pressure, the ink in the pressure chamber 31 is pushed out to the outlet (that is, the first communication hole 21 and the nozzle hole 11) and is ejected from the tip (nozzle opening) of the nozzle hole 11 toward the recording medium 150. ..
　（ノズルプレート）
　図５は、ノズルプレート１０の断面形状を示す、図３における領域Ｃの部分拡大図である。なお、図５では、説明を容易にするため、ノズルプレート１０のみを示し、中間プレート２０の記載を省略している。 (Nozzle plate)
FIG. 5 is a partially enlarged view of the region C in FIG. 3 showing the cross-sectional shape of the nozzle plate 10. Note that in FIG. 5, only the nozzle plate 10 is shown and the intermediate plate 20 is omitted for the sake of simplicity.
　図５に示すように、ノズルプレート１０が有するノズル孔１１は、中間プレート２０側から液滴（インク）の吐出方向に向けてこの順に形成された、第１ラウンド部１１ａ、第２ラウンド部１１ｂ、およびストレート部１１ｃによって構成される。ノズルプレート１０のインクの吐出方向に対し、第１ラウンド部１１ａは最も上流側に配置されており、第２ラウンド部１１ｂは第１ラウンド部１１ａよりも下流側に配置されており、ストレート部１１ｃは第１ラウンド部１１ａよりも下流側の、最も下流側に配置されている。 As shown in FIG. 5, the nozzle holes 11 of the nozzle plate 10 are formed in this order from the side of the intermediate plate 20 in the ejection direction of liquid droplets (ink), and the first round portion 11a and the second round portion 11b are formed. , And the straight portion 11c. The first round portion 11a is arranged on the most upstream side with respect to the ink ejection direction of the nozzle plate 10, the second round portion 11b is arranged on the downstream side of the first round portion 11a, and the straight portion 11c. Is arranged on the most downstream side, which is on the downstream side of the first round portion 11a.
　第１ラウンド部１１ａは、ノズル孔１１のうち、最も中間プレート２０側に配置された空間であり、中間プレート２０の第１連通孔２１から押し出されたインクが最初に到達して流入する空間である。 The first round portion 11a is a space arranged closest to the intermediate plate 20 in the nozzle hole 11, and is a space into which the ink pushed out from the first communication hole 21 of the intermediate plate 20 first reaches and flows in. is there.
　後述するように、第１ラウンド部１１ａは、等方性エッチングにより形成された空間である。第１ラウンド部１１ａは、図５に示す断面形状（すなわち、液滴の吐出方向に平行な平面に沿った断面形状）において、外側に凸の曲面によって外縁が規定され、かつ、第１連通孔２１側から第２ラウンド部１１ｂ側にかけて（すなわち、インクの吐出方向に向かって）径が縮小する、形状を有する。 As will be described later, the first round portion 11a is a space formed by isotropic etching. The first round portion 11a has an outer edge defined by an outwardly convex curved surface in the cross-sectional shape shown in FIG. 5 (that is, a cross-sectional shape along a plane parallel to the droplet ejection direction), and the first communicating hole. It has a shape in which the diameter decreases from the side of 21 to the side of the second round portion 11b (that is, toward the ink ejection direction).
　第２ラウンド部１１ｂは、第１ラウンド部１１ａとストレート部１１ｃとの間に配置され、第１ラウンド部１１ａとストレート部１１ｃとを連通する空間である。 The second round portion 11b is a space that is arranged between the first round portion 11a and the straight portion 11c and connects the first round portion 11a and the straight portion 11c.
　後述するように、第２ラウンド部１１ｂは、第１ラウンド部１１ａを形成するときの等方性エッチングとは異なる条件での等方性エッチングにより形成された空間である。第２ラウンド部１１ｂは、図５に示す断面形状において、外側に凸の曲面によって外縁が規定され、かつ、第１ラウンド部１１ａ側からストレート部１１ｃ側にかけて（すなわち、インクの吐出方向に向かって）径が縮小する、形状を有する。また、第２ラウンド部１１ｂは、図５に示す断面形状において、その外縁の形状が第１ラウンド部１１ａの外縁の形状とは非相似である。 As will be described later, the second round portion 11b is a space formed by isotropic etching under conditions different from the isotropic etching used when forming the first round portion 11a. In the cross-sectional shape shown in FIG. 5, the second round portion 11b has an outer edge defined by an outwardly convex curved surface, and extends from the first round portion 11a side to the straight portion 11c side (that is, toward the ink ejection direction). ) Having a shape in which the diameter is reduced. In addition, in the cross-sectional shape shown in FIG. 5, the second round portion 11b has an outer edge shape that is not similar to the outer edge shape of the first round portion 11a.
　ストレート部１１ｃは、ノズル孔１１のうち、最も吐出面側に配置された空間であり、第１ラウンド部１１ａおよび第２ラウンド部１１ｂを通過したインクが到達して流入し、かつノズルプレート１０の外部（すなわち、インクジェットヘッド１の外部）へと吐出される空間である。 The straight portion 11c is a space that is arranged closest to the ejection surface of the nozzle hole 11, and the ink that has passed through the first round portion 11a and the second round portion 11b arrives and flows in the straight portion 11c of the nozzle plate 10. It is a space that is ejected to the outside (that is, the outside of the inkjet head 1).
　後述するように、ストレート部１１ｃは、異方性エッチングにより形成された空間である。そのため、ストレート部１１ｃは、図５に示す断面形状において、第２ラウンド部１１ｂ側からインクの吐出面側にかけて（すなわち、インクの吐出方向に向かって）径が一定である形状を有する。 As will be described later, the straight portion 11c is a space formed by anisotropic etching. Therefore, in the cross-sectional shape shown in FIG. 5, the straight portion 11c has a shape in which the diameter is constant from the second round portion 11b side to the ink ejection surface side (that is, toward the ink ejection direction).
　図５に示す断面形状において、第１ラウンド部１１ａ、第２ラウンド部１１ｂ、およびストレート部１１ｃは、同一の仮想直線Ｚを対称軸とした線対称の形状を有する。なお、第１ラウンド部１１ａ、第２ラウンド部１１ｂ、およびストレート部１１ｃは、３次元空間においても軸Ｚを対象軸とするｎ回の回転対称（ｎは任意の整数）の形状を有する。 In the cross-sectional shape shown in FIG. 5, the first round portion 11a, the second round portion 11b, and the straight portion 11c have line-symmetrical shapes with the same virtual straight line Z as the axis of symmetry. The first round portion 11a, the second round portion 11b, and the straight portion 11c have a shape of n times rotational symmetry (n is an arbitrary integer) about the axis Z in the three-dimensional space.
　そのため、第１ラウンド部１１ａが中間プレート２０側へ開口する開口面である開口部１２ａ、第１ラウンド部１１ａと第２ラウンド部１１ｂとの境界面である第１境界部１２ｂ、第２ラウンド部１１ｂとストレート部１１ｃとの境界面である第２境界部１２ｃ、および、ストレート部１１ｃがインクの吐出面側へ開口する開口面である開口部１２ｄ、はいずれも円形であり、かつその中心が同一の軸Ｚ上に存在するように、ノズルプレート１０の平面視において同心円状に配置されている。 Therefore, the first round portion 11a has an opening portion 12a that is an opening surface that opens toward the intermediate plate 20, the first boundary portion 12b that is the boundary surface between the first round portion 11a and the second round portion 11b, and the second round portion. The second boundary portion 12c, which is the boundary surface between the straight portion 11c and the straight portion 11c, and the opening portion 12d, which is the opening surface of the straight portion 11c that opens toward the ink ejection surface side, are both circular and have their centers. The nozzle plates 10 are arranged concentrically in a plan view so as to exist on the same axis Z.
　なお、本実施形態において、第１ラウンド部１１ａと第２ラウンド部１１ｂとの境界面である第１境界部１２ｂは、図５に示す断面図において、くびれ形状であり、内側に凸となっている。第１境界部１２ｂは、図５に示す断面図において、第１ラウンド部１１ａの外縁を規定する線と第２ラウンド部１１ｂの外縁を規定する線との交点が頂点となっていてもよいし、上記交点が所定のＲのまるみを有していてもよい。 In the present embodiment, the first boundary portion 12b, which is the boundary surface between the first round portion 11a and the second round portion 11b, has a constricted shape in the sectional view shown in FIG. There is. In the cross-sectional view shown in FIG. 5, the first boundary portion 12b may have an apex at the intersection of the line defining the outer edge of the first round portion 11a and the line defining the outer edge of the second round portion 11b. , The intersection may have a predetermined roundness of R.
　また、第２境界部１２ｃの径と開口部１２ｄの径とは略同一である。 The diameter of the second boundary 12c and the diameter of the opening 12d are substantially the same.
　図６は、ノズル孔１１の容積を示すための、図５に示したノズル孔１１の模式断面図である。上記形状を有するノズル孔１１は、図６に示す断面図において、第１ラウンド部１１ａの断面積と第２ラウンド部１１ｂの断面積とを合計した断面積を、開口部１２ａの径（図５におけるＤａ）を上辺の長さとし、第２境界部１２ｃの径（図５におけるＤｃ）を下辺の長さとし、第１ラウンド部の深さおよび第２ラウンド部の深さの合計（図５におけるＬａ＋Ｌｂ）を高さとする仮想台形（図６の斜線部）の断面積よりも大きくすることができる。これにより、ノズル孔１１は、第１ラウンド部１１ａの容積と第２ラウンド部１１ｂの容積とを合計した容積を、第１ラウンド部および第２ラウンド部が直線によって外縁が規定されたときの容積よりも広くして、ノズル孔１１に収容できるインクの量をより多くすることができる。 FIG. 6 is a schematic cross-sectional view of the nozzle hole 11 shown in FIG. 5 for showing the volume of the nozzle hole 11. In the nozzle hole 11 having the above shape, in the cross-sectional view shown in FIG. 6, the total cross-sectional area of the first round portion 11a and the second round portion 11b is calculated as the diameter of the opening 12a (FIG. 5). Is the length of the upper side and the diameter of the second boundary portion 12c (Dc in FIG. 5) is the length of the lower side. ) Can be made larger than the cross-sectional area of the virtual trapezoid (hatched portion in FIG. 6). As a result, the nozzle hole 11 has a volume obtained by summing the volumes of the first round portion 11a and the second round portion 11b when the outer edges of the first round portion and the second round portion are defined by straight lines. The amount of ink that can be accommodated in the nozzle holes 11 can be increased by increasing the width.
　なお、このとき、図６に示すように、第１境界部１２ｂの縁は、第２境界部１２ｃの縁のうち任意の一点と、開口部１２ａの縁のうち上記任意の一点から最も近い一点と、を結んだ直線（すなわち、上記仮想台形の斜辺）よりも、外側にあってもよいし、内側にあってもよい。すなわち、図６に示す断面図において、第１ラウンド部１１ａの側面を示す曲線および第２ラウンド部１１ｂの側面を示す曲面は、上記仮想台形の斜辺とは交わらなくてもよいし、交わってもよい。 At this time, as shown in FIG. 6, the edge of the first boundary portion 12b is an arbitrary one point of the edges of the second boundary portion 12c and the one point of the edges of the opening 12a that is closest to the arbitrary point. And may be outside or inside the straight line connecting the lines and (that is, the hypotenuse of the virtual trapezoid). That is, in the cross-sectional view shown in FIG. 6, the curved line indicating the side surface of the first round portion 11a and the curved surface indicating the side surface of the second round portion 11b may or may not intersect with the hypotenuse of the virtual trapezoid. Good.
　ところで、図７は、等方性エッチングを１回のみ行うことにより上流側のラウンド部（本実施形態に関するノズルプレート１０が有するノズル孔１１の第１ラウンド部１１ａおよび第２ラウンド部１１ｂに相当する空間）を作製したときの、ノズル孔の形状を示す断面図である。図７では、上記等方性エッチングを１回のみ行って形成された空間を有するノズル孔の形状を実線で、本実施形態に関するノズルプレート１０が有するノズル孔１１の形状を点線で、それぞれ示す。 By the way, FIG. 7 corresponds to the round portion on the upstream side (corresponding to the first round portion 11a and the second round portion 11b of the nozzle hole 11 included in the nozzle plate 10 according to the present embodiment by performing the isotropic etching only once. It is sectional drawing which shows the shape of a nozzle hole when producing (space). In FIG. 7, the shape of the nozzle hole having a space formed by performing the above-mentioned isotropic etching only once is indicated by a solid line, and the shape of the nozzle hole 11 included in the nozzle plate 10 according to the present embodiment is indicated by a dotted line.
　図７Ａは、本実施形態における第１ラウンド部１１ａの深さと第２ラウンド部１１ｂの深さとを合計した深さと同程度の深さの空間１１ｅを上流側に形成したときのノズル孔の典型的な形状を示す模式図である。このとき、サイドエッチによりノズル孔の開口部１２ｅの径もより大きくなってしまうため、ノズル孔を高密度で配置することが困難である。図７Ｂは、バイアスパワーを大きくするなどしてエッチングガスから生成したイオンによるスパッタ量を多くすることで、深さ方向へのエッチング速度を高めて、第１ラウンド部１１ａの深さと第２ラウンド部１１ｂの深さとを合計した深さを有する空間１１ｆを上流側に形成したときのノズル孔の典型的な形状を示す模式図である。このとき、サイドエッチによるアンダーカット幅が不足しがちとなってノズル孔の開口部１２ｆの径をさほど大きくすることができず、ノズル孔に収容できるインクの量をさほど多くすることはできない。 FIG. 7A is a typical nozzle hole when a space 11e having the same depth as the total depth of the first round portion 11a and the second round portion 11b in the present embodiment is formed on the upstream side. It is a schematic diagram which shows a different shape. At this time, since the diameter of the opening 12e of the nozzle hole becomes larger due to side etching, it is difficult to arrange the nozzle holes at a high density. FIG. 7B shows that the etching rate in the depth direction is increased by increasing the amount of sputtering by the ions generated from the etching gas by increasing the bias power, thereby increasing the depth of the first round portion 11a and the second round portion. It is a schematic diagram which shows the typical shape of the nozzle hole at the time of forming the space 11f which has the depth which totaled the depth of 11b at the upstream side. At this time, the undercut width due to side etching tends to be insufficient, and the diameter of the opening 12f of the nozzle hole cannot be increased so much, and the amount of ink that can be stored in the nozzle hole cannot be increased so much.
　これに対し、２回の等方性エッチングにより第１ラウンド部１１ａおよび第２ラウンド部１１ｂを有するノズル孔１１を形成すると、１回目の等方性エッチングでサイドエッチによるアンダーカット幅を適度に広くし、その後、バイアスパワーなどの条件を変更した２回目の等方性エッチングでノズル孔の深さをより深くすることができる。そのため、第１ラウンド部１１ａの径を適度に広くして、かつ上記深さも十分に深くした、ノズル孔１１を形成することができる。 On the other hand, when the nozzle hole 11 having the first round portion 11a and the second round portion 11b is formed by performing the isotropic etching twice, the undercut width due to the side etching is appropriately widened in the first isotropic etching. Then, the depth of the nozzle hole can be made deeper by the second isotropic etching after changing the conditions such as the bias power. Therefore, it is possible to form the nozzle hole 11 in which the diameter of the first round portion 11a is appropriately widened and the depth is sufficiently deep.
　また、２回目の等方性エッチングでノズル孔の深さがより深くなるように形成した第２ラウンド部１１ｂは、インクの吐出方向に向かっての径の縮小率がより小さくなっている。このような第２ラウンド部１１ｂは、インクの吐出速度や直進性を高めるという、ストレート部１１ｃに似た作用も有する。そのため、２回の等方性エッチングにより第１ラウンド部１１ａおよび第２ラウンド部１１ｂを有するノズル孔１１を形成すると、第１ラウンド部１１ａおよび第２ラウンド部１１ｂによってインクの吐出量を多くしつつ、第２ラウンド部１１ｂおよびストレート部１１ｃによって吐出性能も同時に高められたノズル孔１１を形成することができる。 Further, the second round portion 11b formed by the second isotropic etching so that the depth of the nozzle hole becomes deeper has a smaller reduction rate of the diameter in the ink ejection direction. Such a second round portion 11b also has an effect similar to that of the straight portion 11c, that is, increasing the ink ejection speed and straightness. Therefore, when the nozzle hole 11 having the first round portion 11a and the second round portion 11b is formed by performing the isotropic etching twice, the ink ejection amount is increased by the first round portion 11a and the second round portion 11b. The second round portion 11b and the straight portion 11c can form the nozzle hole 11 whose ejection performance is also improved.
　一方で、ノズル孔１１は、異方性エッチングによりストレート部１１ｃが形成されているため、ストレート部１１ｃの径の大きさは比較的自由に制御できる。 On the other hand, in the nozzle hole 11, since the straight portion 11c is formed by anisotropic etching, the diameter of the straight portion 11c can be controlled relatively freely.
　そのため、ノズル孔１１は、インクの吐出特性に影響するストレート部１１ｃの径を変更せずに、ノズル孔１１に収容できるインクの量をより多くして、１回の動作で吐出できる液滴量をより多くすることができる。 Therefore, the nozzle hole 11 increases the amount of ink that can be accommodated in the nozzle hole 11 without changing the diameter of the straight portion 11c that affects the ink ejection characteristics, and the amount of droplets that can be ejected in one operation. Can be more.
　このとき、開口部１２ａの径をＤａ、第１境界部１２ｂの径をＤｂ、第２境界部１２ｃおよび開口部１２ｄの径をＤｃとするとき、Ｄｂ／Ｄａは０．３５以上０．８５以下であることが好ましく、０．５以上０．７以下であることがより好ましい。また、Ｄｃ／Ｄａは０．１以上０．３５以下であることが好ましく、０．１５以上０．３以下であることがより好ましい。 At this time, when the diameter of the opening 12a is Da, the diameter of the first boundary 12b is Db, and the diameters of the second boundary 12c and the opening 12d are Dc, Db/Da is 0.35 or more and 0.85 or less. Is preferable, and more preferably 0.5 or more and 0.7 or less. Further, Dc/Da is preferably 0.1 or more and 0.35 or less, and more preferably 0.15 or more and 0.3 or less.
　具体的には、Ｄａは、５０μｍ以上１５０μｍ以下であることが好ましく、５５μｍ以上１００μｍ以下であることがより好ましい。また、Ｄｂは、３０μｍ以上８０μｍ以下であることが好ましく、３５μｍ以上７０μｍ以下であることがより好ましい。また、Ｄｃは、１０μｍ以上４０μｍ以下であることが好ましく、１５μｍ以上３０μｍ以下であることがより好ましい。 Specifically, Da is preferably 50 μm or more and 150 μm or less, and more preferably 55 μm or more and 100 μm or less. Further, Db is preferably 30 μm or more and 80 μm or less, and more preferably 35 μm or more and 70 μm or less. Further, Dc is preferably 10 μm or more and 40 μm or less, and more preferably 15 μm or more and 30 μm or less.
　なお、本実施形態において、インクの吐出方向に垂直な平面に沿った断面形状において、開口部１２ａ、第１境界部１２ｂ、第２境界部１２ｃおよび開口部１２ｄの形状は円形であるが、楕円系などの他の形状であってもよい。開口部１２ａ、第１境界部１２ｂ、第２境界部１２ｃおよび開口部１２ｄの形状が円形ではないとき、上記Ｄａ、ＤｂおよびＤｃは、それぞれの短径とすればよい。 In the present embodiment, in the cross-sectional shape along the plane perpendicular to the ink ejection direction, the shape of the opening 12a, the first boundary 12b, the second boundary 12c, and the opening 12d is circular, but the shape is elliptical. Other shapes such as a system may be used. When the shapes of the opening 12a, the first boundary portion 12b, the second boundary portion 12c, and the opening 12d are not circular, Da, Db, and Dc may have their respective short diameters.
　また、第１ラウンド部１１ａの深さをＬａ、第２ラウンド部１１ｂの深さをＬｂ、ストレート部１１ｃの深さをＬｃとするとき、Ｌａ／Ｌｂは０．１以上３以下であることが好ましく、０．２以上１．５以下であることがより好ましい。また、Ｌｃ／（Ｌａ＋Ｌｂ）は０．２以上２以下であることが好ましく、０．５以上１．５以下であることがより好ましい。 Further, when the depth of the first round portion 11a is La, the depth of the second round portion 11b is Lb, and the depth of the straight portion 11c is Lc, La/Lb is 0.1 or more and 3 or less. It is preferably 0.2 or more and 1.5 or less. Further, Lc/(La+Lb) is preferably 0.2 or more and 2 or less, and more preferably 0.5 or more and 1.5 or less.
　具体的には、Ｌａは、５μｍ以上５０μｍ以下であることが好ましく、１０μｍ以上３０μｍ以下であることがより好ましい。また、Ｌｂは、１０μｍ以上５０μｍ以下であることが好ましく、１５μｍ以上４０μｍ以下であることがより好ましい。また、Ｌｃは、１０μｍ以上５０μｍ以下であることが好ましく、１５μｍ以上３０μｍ以下であることがより好ましい。 Specifically, La is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less. Further, Lb is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 40 μm or less. Further, Lc is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 30 μm or less.
　後述するように、第１ラウンド部１１ａ、第２ラウンド部１１ｂ、およびストレート部１１ｃは、単結晶シリコンの１枚のシリコンウエハを加工して作製することができる。 As will be described later, the first round portion 11a, the second round portion 11b, and the straight portion 11c can be manufactured by processing one silicon wafer of single crystal silicon.
　（ノズルプレートの作製）
　図８～図１１は、本実施形態に関するインクジェットヘッド１が有するノズルプレート１０を作製する方法の一例を示す説明図である。なお、図８～図１１では、理解の容易のため、一部の部材の縮尺を変更している。 (Production of nozzle plate)
8 to 11 are explanatory views showing an example of a method of manufacturing the nozzle plate 10 included in the inkjet head 1 according to this embodiment. Note that in FIGS. 8 to 11, the scales of some members are changed for easier understanding.
　まず、図８Ａに示すように、単結晶のシリコンウエハ７１０上にレジストを塗布し、露光および現像して、レジストパターン７１５を形成する。レジストパターン７１５は、ノズル孔１１のストレート部１１ｃが形成される位置に、ストレート部１１ｃが有する第２境界部１２ｃと同一形状である略円形の形状で、シリコンウエハ７１０の表面が露出するような開口部７１５ａを有するように、形成すればよい。レジストパターン７１５の厚みは、この後の第１の等方性エッチング、第２の等方性エッチングおよび異方性エッチングに耐え得る厚みであればよく、それぞれのエッチング条件に応じて選択することができる。 First, as shown in FIG. 8A, a resist is applied on a single crystal silicon wafer 710, exposed and developed to form a resist pattern 715. The resist pattern 715 has a substantially circular shape that is the same as the second boundary portion 12c of the straight portion 11c at the position where the straight portion 11c of the nozzle hole 11 is formed, and the surface of the silicon wafer 710 is exposed. It may be formed so as to have the opening 715a. The thickness of the resist pattern 715 may be a thickness that can withstand the subsequent first isotropic etching, second isotropic etching, and anisotropic etching, and can be selected according to each etching condition. it can.
　なお、本実施形態では、レジストパターン７１５の形状は略円形としたが、楕円系などとしてもよい。 Although the resist pattern 715 has a substantially circular shape in the present embodiment, it may have an elliptical shape or the like.
　次に、図８Ｂに示すように、レジストパターン７１５をマスクとして、第１の等方性エッチングを行う。第１の等方性エッチングは、たとえば、エッチングガスとしてＳＦ６等のフッ素ガスなどを使用し、エッチングガスの流量を２００ｓｃｃｍ、圧力を１０Ｐａ、バイアスパワーを１０Ｗとした、ドライエッチングにより行うことができる。第１の等方性エッチングにより、図８Ｂに示すように、シリコンウエハ７１０を厚み方向に切断して得られる断面において、側面形状が曲線である、深さ方向に径が縮小する第１のラウンド状パターン７１１ａが形成される。このとき、サイドエッチによるアンダーカット部も形成されるため、第１のラウンド状パターン７１１ａの最大幅は、レジストパターン７１５の開口部７１５ａの幅よりも広くなる。 Next, as shown in FIG. 8B, a first isotropic etching is performed using the resist pattern 715 as a mask. The first isotropic etching can be performed, for example, by dry etching using a fluorine gas such as SF 6 as an etching gas, the flow rate of the etching gas is 200 sccm, the pressure is 10 Pa, and the bias power is 10 W. .. As shown in FIG. 8B, in the cross section obtained by cutting the silicon wafer 710 in the thickness direction by the first isotropic etching, the first round having a curved side surface shape and a reduced diameter in the depth direction. Pattern 711a is formed. At this time, since the undercut portion due to side etching is also formed, the maximum width of the first round pattern 711a is wider than the width of the opening 715a of the resist pattern 715.
　次に、図８Ｃに示すように、レジストパターン７１５をマスクとして、第１の等方性エッチングとは異なる条件で第２の等方性エッチングを行う。第２の等方性エッチングは、第１の等方性エッチングよりも深さ方向へのエッチング速度が高い条件で行えばよく、たとえば、第１の等方性エッチングよりもバイアスパワーを大きくした条件で行えばよい。第２の等方性エッチングは、たとえば、エッチングガスとしてＳＦ６等のフッ素ガスなどを使用し、エッチングガスの流量を２００ｓｃｃｍ、圧力を１０Ｐａ、バイアスパワーを６０Ｗとした、ドライエッチングにより行うことができる。第２の等方性エッチングにより、図８Ｃに示すように、シリコンウエハ７１０を厚み方向に切断して得られる断面において、側面形状が曲線である、深さ方向に径が縮小する第２のラウンド状パターン７１１ｂが形成される。このとき、第１のラウンド状パターン７１１ａの幅と同様に、第２のラウンド状パターン７１１ｂの最大幅は、レジストパターン７１５の開口部７１５ａの幅よりも広くなる。 Next, as shown in FIG. 8C, using the resist pattern 715 as a mask, second isotropic etching is performed under conditions different from those of the first isotropic etching. The second isotropic etching may be performed under the condition that the etching rate in the depth direction is higher than that of the first isotropic etching. For example, the condition that the bias power is larger than that of the first isotropic etching is used. You can go in. The second isotropic etching can be performed, for example, by dry etching using a fluorine gas such as SF 6 as an etching gas, the flow rate of the etching gas is 200 sccm, the pressure is 10 Pa, and the bias power is 60 W. .. In the cross section obtained by cutting the silicon wafer 710 in the thickness direction by the second isotropic etching, as shown in FIG. 8C, a second round in which the side shape is a curve and the diameter is reduced in the depth direction. Pattern 711b is formed. At this time, the maximum width of the second round-shaped pattern 711b is larger than the width of the opening 715a of the resist pattern 715, like the width of the first round-shaped pattern 711a.
　第１の等方性エッチングと第２の等方性エッチングのエッチング条件は、主としてバイアスパワーを変えることにより形成される形状の制御を行うように設定する。上記バイアスパワーの範囲は、第１の等方性エッチングでは１０Ｗから３０Ｗの範囲、第２の等方性エッチングでは５０Ｗから８０Ｗの範囲が好ましい。エッチングのガス種も、フッ素系の他の組成や酸素を添加する事により、形状をよりよく制御することが可能となる。また投入するＩＣＰパワーは、１０００から２０００Ｗの範囲が好ましい。 The etching conditions for the first isotropic etching and the second isotropic etching are set so as to control the shape formed mainly by changing the bias power. The range of the bias power is preferably 10 W to 30 W in the first isotropic etching and 50 W to 80 W in the second isotropic etching. The shape of the etching gas species can be better controlled by adding another fluorine-based composition or oxygen. The ICP power to be applied is preferably in the range of 1000 to 2000W.
　次に、図９Ａに示すように、レジストパターン７１５をマスクとして、異方性エッチングを行う。上記異方性エッチングは、通称ボッシュプロセスと呼ばれる異方性エッチングに対応した機能を有した装置を用い、前記等方性エッチングから異方性エッチングにモードを切り替えることで繰り返して行えばよい。上記異方性エッチングは、たとえば、エッチングガスとしてＳＦ６等のフッ素系ガスなどを使用し、パッシベーションガスとしてＣ４Ｆ８等を用いて異方性のエッチングを行う。エッチングガスの流量を５００ｓｃｃｍ、パッシベーションガスの流量を６００ｓｃｃｍ、圧力を１０Ｐａ、バイアスパワーを６０Ｗとした、ドライエッチングにより行うことができる。上記異方性エッチングにより、図９Ａに示すように、シリコンウエハ７１０を厚み方向に切断して得られる断面において、側面形状が直線である、深さ方向に径が一定であるストレート状パターン７１１ｃが形成される。このとき、ストレート状パターン７１１ｃの幅は、レジストパターン７１５の開口部７１５ａの幅と略同一である。 Next, as shown in FIG. 9A, anisotropic etching is performed using the resist pattern 715 as a mask. The above-mentioned anisotropic etching may be repeated by switching the mode from the isotropic etching to the anisotropic etching using an apparatus having a function corresponding to the anisotropic etching commonly called Bosch process. The anisotropic etching is performed by using, for example, a fluorine-based gas such as SF 6 as an etching gas and C 4 F 8 as a passivation gas. Dry etching can be performed with an etching gas flow rate of 500 sccm, a passivation gas flow rate of 600 sccm, a pressure of 10 Pa, and a bias power of 60 W. As shown in FIG. 9A, in the cross section obtained by cutting the silicon wafer 710 in the thickness direction by the anisotropic etching, a straight pattern 711c having a straight side surface shape and a constant diameter in the depth direction is formed. It is formed. At this time, the width of the straight pattern 711c is substantially the same as the width of the opening 715a of the resist pattern 715.
　次に、図９Ｂに示すように、レジスト（レジストパターン７１５）を除去する。そして、図９Ｃに示すように、ポジ型レジストや感光性ポリイミドなどの感光性材料７１６ａを、シリコンウエハ７１０の表面に付与する。このとき、付与された感光性材料７１６ａがストレート状パターン７１１ｃの内部にまで十分に導入されるよう、低速度のコータ－で感光性材料を付与したり、シリコンウエハ７１０を感光性材料に浸漬したりすればよい。その後、図１０Ａに示すように、ストレート状パターン７１１ｃの幅よりも大きい幅を有するフォトマスクを１０１０用いて、感光性材料７１６ａを露光し、硬化させる。これにより、図１０Ｂに示すように、少なくともストレート状パターン７１１ｃの内部に感光性材料の硬化物７１６ｂ（保護材料）が充填されるように、感光性材料７１６ａを硬化させることができる。 Next, as shown in FIG. 9B, the resist (resist pattern 715) is removed. Then, as shown in FIG. 9C, a photosensitive material 716 a such as a positive resist or photosensitive polyimide is applied to the surface of the silicon wafer 710. At this time, the photosensitive material is applied by a low-speed coater or the silicon wafer 710 is dipped in the photosensitive material so that the applied photosensitive material 716a is sufficiently introduced into the straight pattern 711c. You can do it. Then, as shown in FIG. 10A, the photosensitive material 716a is exposed and cured using a photomask 1010 having a width larger than the width of the straight pattern 711c. As a result, as shown in FIG. 10B, the photosensitive material 716a can be cured so that at least the inside of the straight pattern 711c is filled with the cured material 716b (protective material) of the photosensitive material.
　次に、図１１Ａに示すように、第１のラウンド状パターン７１１ａの開口部を覆うように、シリコンウエハ７１０に保護膜７１７を貼り付けて、シリコンウエハ７１０を上下反転させる。保護膜７１７は、第１のラウンド状パターン７１１ａの開口部を被覆して、シリコンウエハ７１０を上下反転させたときの感光性材料の硬化物７１６ｂの脱落を防ぐことができるものであればよく、シリコンウエハ、ＳｉＣウエハ、およびガラス板などを用いることができる。そして、第１のラウンド状パターン７１１ａ～ストレート状パターン７１１ｃが形成された面とは反対側の面から、シリコンウエハ７１０を研削する。研削は、少なくともストレート状パターン７１１ｃおよび感光性材料の硬化物７１６ｂが露出するまで行う。その後、研磨により研削面を鏡面加工する。 Next, as shown in FIG. 11A, a protective film 717 is attached to the silicon wafer 710 so as to cover the opening of the first round pattern 711a, and the silicon wafer 710 is turned upside down. The protective film 717 may cover the opening of the first round-shaped pattern 711a so as to prevent the cured material 716b of the photosensitive material from falling off when the silicon wafer 710 is turned upside down, A silicon wafer, a SiC wafer, a glass plate, or the like can be used. Then, the silicon wafer 710 is ground from the surface opposite to the surface on which the first round pattern 711a to the straight pattern 711c are formed. The grinding is performed at least until the straight pattern 711c and the cured material 716b of the photosensitive material are exposed. After that, the ground surface is mirror-finished by polishing.
　次に、図１１Ｂに示すように、上記研磨および鏡面加工した面に、撥液膜７１３を形成する。撥液膜７１３は、インクに対する撥液性を有するものであればよく、たとえば、フッ素系などの撥液剤を含む溶液を塗布し、焼成すればよい。このとき、ストレート状パターン７１１ｃは感光性材料の硬化物７１６ｂで充填されているため、上記水溶液はストレート状パターン７１１ｃの内部には侵入しない。 Next, as shown in FIG. 11B, a liquid repellent film 713 is formed on the polished and mirror-finished surface. The liquid repellent film 713 may have any liquid repellent property with respect to the ink, and for example, a solution containing a liquid repellent agent such as fluorine may be applied and baked. At this time, since the straight pattern 711c is filled with the cured material 716b of the photosensitive material, the aqueous solution does not enter the inside of the straight pattern 711c.
　次に、図１１Ｃに示すように、保護膜７１７を除去し、感光性材料の硬化物７１６ａも除去する。感光性材料の硬化物７１６ｂを除去するとき、感光性材料の硬化物７１６ｂの表面に堆積した撥液膜７１３もリフトオフされ、同時に除去される。 Next, as shown in FIG. 11C, the protective film 717 is removed, and the cured material 716a of the photosensitive material is also removed. When the cured material 716b of the photosensitive material is removed, the liquid repellent film 713 deposited on the surface of the cured material 716b of the photosensitive material is also lifted off and simultaneously removed.
　最後に、Ｏ２プラズマなどにより汚染の除去などを行い、洗浄液などで洗浄した後、シリコンウエハ７１０を所望の形状に切断して個別化することで、ノズルプレート１０を得ることができる。 Finally, the nozzle plate 10 can be obtained by removing contaminants by O 2 plasma or the like, cleaning with a cleaning liquid or the like, and then cutting the silicon wafer 710 into a desired shape for individualization.
　このようにして得られたノズルプレート１０は、別途用意された中間プレート２０に接合され、さらに圧力室形成プレート３０、駆動プレート４０、および配線基板５０と接合されることにより、ヘッドチップ４とすることができる。さらに、ヘッドチップ４を、共通インク室２、保持部３、およびフレキシブル配線基板５と接合することで、インクジェットヘッド１を得ることができる。このインクジェットヘッド１は、公知のインクジェット法による画像形成装置に搭載させることができる。 The nozzle plate 10 thus obtained is joined to the separately prepared intermediate plate 20, and further joined to the pressure chamber forming plate 30, the drive plate 40, and the wiring substrate 50 to form the head chip 4. be able to. Furthermore, the ink jet head 1 can be obtained by joining the head chip 4 to the common ink chamber 2, the holding portion 3, and the flexible wiring board 5. The inkjet head 1 can be mounted on an image forming apparatus using a known inkjet method.
　なお、上記実施形態は、本発明を実施するにあたっての具体化の一例を示したものに過ぎず、これよって本発明の技術的範囲が限定的に解釈されてはならないものである。すなわち、本発明はその要旨、またはその主要な特徴から逸脱することなく、様々な形で実施することができる。 It should be noted that the above-described embodiment is merely an example of the implementation in carrying out the present invention, and therefore, the technical scope of the present invention should not be limitedly interpreted. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.
　たとえば、上記実施形態では、圧電素子を有するピエゾ式のインクジェットヘッドを説明に用いたが、サーマルジェット式などの他の方式のインクジェットヘッドに対して、上記ノズルプレートを有するノズル板を適用してもよい。 For example, in the above-described embodiment, the piezo type inkjet head having the piezoelectric element is used for description, but the nozzle plate having the nozzle plate may be applied to another type of inkjet head such as a thermal jet type. Good.
　本発明のノズルプレートによれば、インクジェットヘッドからの液滴の吐出特性を制御しつつ、１回の動作で吐出できる液滴量を多くすることができる。そのため、本発明のノズルプレートによれば、形成する画像のさらなる高精細化およびより効率的な画像形成が可能となるため、画像形成やパターン形成などの分野へのインクジェットヘッドのさらなる普及への貢献が期待される。 According to the nozzle plate of the present invention, it is possible to increase the amount of droplets that can be ejected in one operation while controlling the ejection characteristics of droplets from the inkjet head. Therefore, according to the nozzle plate of the present invention, it is possible to further increase the definition of the image to be formed and to form the image more efficiently, and thus contribute to the further spread of the inkjet head in the fields such as image formation and pattern formation. There is expected.
　１　インクジェットヘッド
　２　共通インク室
　２ａ　インク供給口
　２ｂ　インク排出口
　３　保持部
　３ａ　開口部
　４　ヘッドチップ
　５　フレキシブル配線基板
　１０　ノズルプレート
　１１　ノズル孔
　１１ａ　第１ラウンド部
　１１ｂ　第２ラウンド部
　１１ｃ　ストレート部
　１１ｅ　空間
　１１ｆ　空間
　１２ａ　開口部
　１２ｂ　第１境界部
　１２ｃ　第２境界部
　１２ｄ　開口部
　１２ｅ　開口部
　１２ｆ　開口部
　１３　撥液膜
　２０　中間プレート
　２１　第１連通孔
　３０　圧力室形成プレート
　３１　圧力室
　３２　振動板
　３３　隔壁
　３３ａ　第１の隔壁部材
　３３ｂ　第２の隔壁部材
　３４　第２連通孔
　４０　駆動プレート
　４１　空間部
　４２　第３連通孔
　５０　配線基板
　５１　配線層
　５１ａ　半田
　５２　シリコン層
　５３　第４連通孔
　６０　アクチュエータ
　６１　圧電素子
　６２　第１電極
　６３　第２電極
　１００　画像形成装置
　１２０　インク供給装置
　１３０　搬送装置
　１３１　ベルトコンベア
　１３２　送りローラー
　１３３ａ、１３３ｂ　プーリー
　１３４　ベルト
　１４０　メインタンク
　１６１、１６２　管
　１６３　バイパス管
　１６４　弁
　７１０　シリコンウエハ
　７１１ａ　第１のラウンド状パターン
　７１１ｂ　第２のラウンド状パターン
　７１１ｃ　ストレート状パターン
　７１３　撥液膜
　７１５　レジストパターン
　７１５ａ　開口部
　７１６ａ　感光性材料
　７１６ｂ　感光性材料の硬化物
　７１７　保護膜
　１０１０　フォトマスク 1 Inkjet head 2 Common ink chamber 2a Ink supply port 2b Ink discharge port 3 Holding part 3a Opening part 4 Head chip 5 Flexible wiring board 10 Nozzle plate 11 Nozzle hole 11a First round part 11b Second round part 11c Straight part 11e Space 11f Space 12a Opening 12b First boundary 12c Second boundary 12d Opening 12e Opening 12f Opening 13 Liquid repellent film 20 Intermediate plate 21 First communicating hole 30 Pressure chamber forming plate 31 Pressure chamber 32 Vibrating plate 33 Partition wall 33a First partition wall member 33b Second partition wall member 34 Second communication hole 40 Drive plate 41 Space portion 42 Third communication hole 50 Wiring board 51 Wiring layer 51a Solder 52 Silicon layer 53 Fourth communication hole 60 Actuator 61 Piezoelectric element 62 First Electrode 63 Second electrode 100 Image forming device 120 Ink supply device 130 Conveying device 131 Belt conveyor 132 Feed roller 133a, 133b Pulley 134 Belt 140 Main tank 161, 162 pipe 163 Bypass pipe 164 Valve 710 Silicon wafer 711a First round pattern 711b Second round pattern 711c Straight pattern 713 Liquid repellent film 715 Resist pattern 715a Opening 716a Photosensitive material 716b Cured product of photosensitive material 717 Protective film 1010 Photomask

Claims (11)

  1. 　液滴を吐出するための複数のノズル孔を有するノズルプレートであって、
    　前記ノズル孔は、
    　前記液滴の吐出方向に対して最も上流側に配置され、かつ前記液滴の吐出方向に向かって径が縮小する第１ラウンド部と、
    　前記第１ラウンド部よりも下流側に配置され、かつ前記液滴の吐出方向に向かって径が縮小する第２ラウンド部と、
    　前記第２ラウンド部よりも下流側に配置され、かつ前記液滴の吐出方向に向かって径が一定であるストレート部と、を有し、
    　前記液滴の吐出方向に平行な平面に沿った断面形状において、
    　　前記第１ラウンド部および前記第２ラウンド部は、いずれも、外側に凸の曲面によって外縁が規定された形状を有し、かつ、
    　　前記第１ラウンド部の外縁と前記第２ラウンド部の外縁との境界部は、内側に凸となっている、
    　ノズルプレート。     A nozzle plate having a plurality of nozzle holes for ejecting droplets,
    The nozzle hole is
    A first round portion which is arranged on the most upstream side with respect to the droplet discharge direction and whose diameter decreases in the droplet discharge direction;
    A second round portion arranged downstream of the first round portion and having a diameter reduced in the discharge direction of the droplets;
    A straight portion that is arranged on the downstream side of the second round portion and has a constant diameter in the discharge direction of the droplets,
    In a cross-sectional shape along a plane parallel to the discharge direction of the droplet,
    Each of the first round part and the second round part has a shape in which an outer edge is defined by a curved surface that is convex outward, and
    The boundary between the outer edge of the first round portion and the outer edge of the second round portion is convex inward.
    Nozzle plate.
  2. 　前記液滴の吐出方向に平行な平面に沿った断面形状において、
    　　前記第１ラウンド部の外縁と前記第２ラウンド部の外縁とは、曲率が異なる、
    　請求項１に記載のノズルプレート。     In a cross-sectional shape along a plane parallel to the discharge direction of the droplet,
    The outer edge of the first round portion and the outer edge of the second round portion have different curvatures,
    The nozzle plate according to claim 1.
  3. 　前記液滴の吐出方向に平行な平面に沿った断面形状において、
    　　前記第１ラウンド部、前記第２ラウンド部、および前記ストレート部は、同一の仮想直線を対称軸とした線対称の形状を有する、
    　請求項２に記載のノズルプレート。     In a cross-sectional shape along a plane parallel to the discharge direction of the droplet,
    The first round portion, the second round portion, and the straight portion have a line-symmetrical shape with the same virtual straight line as the axis of symmetry.
    The nozzle plate according to claim 2.
  4. 　前記液滴の吐出方向に平行な平面に沿った断面形状において、
    　　第１ラウンド部の断面積と第２ラウンド部の断面積とを合計した断面積は、
    　　前記第１ラウンド部が前記ノズルプレートの上流側へ開口する開口部の径（Ｄａ）を上辺の長さとし、
    　　前記ストレート部と前記第２ラウンド部との境界部の径（Ｄｃ）を下辺の長さとし、
    　　前記第１ラウンド部の深さ（Ｌａ）および前記第２ラウンド部の深さ（Ｌｂ）の合計（Ｌａ＋Ｌｂ）を高さとする仮想台形の断面積よりも、大きい、
    　請求項１～３のいずれか１項に記載のノズルプレート。     In a cross-sectional shape along a plane parallel to the discharge direction of the droplet,
    The total cross-sectional area of the first round part and the second round part is
    The diameter (Da) of the opening portion where the first round portion opens to the upstream side of the nozzle plate is the length of the upper side,
    The diameter (Dc) of the boundary between the straight portion and the second round portion is the length of the lower side,
    It is larger than the cross-sectional area of the virtual trapezoid whose height is the sum (La+Lb) of the depth (La) of the first round portion and the depth (Lb) of the second round portion,
    The nozzle plate according to any one of claims 1 to 3.
  5. 　前記第１ラウンド部、前記第２ラウンド部、および前記ストレート部は、ひとつの単結晶シリコンウエハを加工してなる、
    　請求項１～４のいずれか１項に記載のノズルプレート。     The first round portion, the second round portion, and the straight portion are formed by processing one single crystal silicon wafer,
    The nozzle plate according to any one of claims 1 to 4.
  6. 　その一の表面にレジストパターンを形成した単結晶シリコンウエハを、前記レジストパターンをマスクとして等方性エッチングする第１の等方性エッチング工程と、
    　前記単結晶シリコンウエハを、前記レジストパターンをマスクとして、前記第１の等方性エッチング工程とは異なる条件で等方性エッチングする第２の等方性エッチング工程と
    　前記単結晶シリコンウエハを、前記レジストパターンをマスクとして、異方性エッチングする異方性エッチング工程と、をこの順で含む、
    　ノズルプレートの製造方法。     A first isotropic etching step of isotropically etching the single crystal silicon wafer having a resist pattern formed on one surface thereof with the resist pattern as a mask;
    A second isotropic etching step of isotropically etching the single crystal silicon wafer under conditions different from the first isotropic etching step using the resist pattern as a mask, and the single crystal silicon wafer, Anisotropic etching step of anisotropically etching using the resist pattern as a mask, and including in this order,
    Nozzle plate manufacturing method.
  7. 　前記第２の等方性エッチング工程は、前記第１の等方性エッチング工程よりもバイアスパワーを大きくした条件で行われる、
    　請求項６に記載のノズルプレートの製造方法。     The second isotropic etching step is performed under the condition that the bias power is larger than that of the first isotropic etching step.
    The method for manufacturing a nozzle plate according to claim 6.
  8. 　前記異方性エッチング工程の後に、前記単結晶シリコンウエハを、その他の表面側から研削して、前記異方性エッチングにより形成されたパターンを前記他の表面側に露出させる工程を含む、
    　請求項６または７に記載のノズルプレートの製造方法。     After the anisotropic etching step, a step of grinding the single crystal silicon wafer from the other surface side to expose the pattern formed by the anisotropic etching to the other surface side,
    The method for manufacturing a nozzle plate according to claim 6 or 7.
  9. 　前記異方性エッチング工程の後に、前記異方性エッチングにより形成されたパターンの内部に保護材料を充填する工程を有し、
    　前記保護材料を充填する工程の後に、
    　　前記単結晶シリコンウエハの、その他の表面に撥液膜を形成する工程と、
    　　前記保護材料を除去する工程と、
    　を含み、
    　前記保護材料を除去する工程において、前記異方性エッチングにより形成されたパターンが有する前記他の表面への開口に接して形成された前記撥液膜を、リフトオフにより除去する、
    　請求項６～８のいずれか１項に記載のノズルプレートの製造方法。     After the anisotropic etching step, there is a step of filling a protective material inside the pattern formed by the anisotropic etching,
    After the step of filling the protective material,
    Forming a liquid repellent film on the other surface of the single crystal silicon wafer;
    Removing the protective material,
    Including,
    In the step of removing the protective material, the liquid repellent film formed in contact with the opening to the other surface of the pattern formed by the anisotropic etching is removed by lift-off.
    The method for manufacturing a nozzle plate according to any one of claims 6 to 8.
  10. 　請求項１～５のいずれか１項に記載のノズルプレート、または請求項６～９のいずれか１項に記載のノズルプレートの製造方法により製造されたノズルプレートを有する、
    　インクジェットヘッド。     A nozzle plate according to any one of claims 1 to 5, or a nozzle plate manufactured by the method for manufacturing a nozzle plate according to any one of claims 6 to 9,
    Inkjet head.
  11. 　請求項１０に記載のインクジェットヘッドを有する、画像形成装置。
    　
     
    　     An image forming apparatus comprising the inkjet head according to claim 10.


PCT/JP2019/005957 2019-02-19 2019-02-19 Nozzle plate and manufacturing method thereof, inkjet head, and image forming apparatus WO2020170319A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6258286B1 (en) * 1999-03-02 2001-07-10 Eastman Kodak Company Making ink jet nozzle plates using bore liners
JP2002370351A (en) * 2001-06-15 2002-12-24 Fuji Xerox Co Ltd Ink jet recording head and ink jet recorder
JP2006224619A (en) * 2005-02-21 2006-08-31 Brother Ind Ltd Manufacturing method of nozzle plate and nozzle plate
JP2010508136A (en) * 2006-10-25 2010-03-18 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Nozzle for high speed jet injection equipment
JP2018083316A (en) * 2016-11-22 2018-05-31 コニカミノルタ株式会社 Manufacturing method of nozzle plate and manufacturing method of ink jet head

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6258286B1 (en) * 1999-03-02 2001-07-10 Eastman Kodak Company Making ink jet nozzle plates using bore liners
JP2002370351A (en) * 2001-06-15 2002-12-24 Fuji Xerox Co Ltd Ink jet recording head and ink jet recorder
JP2006224619A (en) * 2005-02-21 2006-08-31 Brother Ind Ltd Manufacturing method of nozzle plate and nozzle plate
JP2010508136A (en) * 2006-10-25 2010-03-18 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Nozzle for high speed jet injection equipment
JP2018083316A (en) * 2016-11-22 2018-05-31 コニカミノルタ株式会社 Manufacturing method of nozzle plate and manufacturing method of ink jet head

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