JP2004090297A - Liquid drop ejection head and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that integration is limited in a head employing a diaphragm having an overhanging part. <P>SOLUTION: The diaphragm 2 has a thick part 12 abutting against a piezoelectric element 7, and a thin part 11 around the thick part 12. The thick part 12 has a pattern edge part overhanging in two steps with respect to the thin part 11 wherein the total thickness of the thin part 11 and the thick part 12 is 10 μm or above. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a droplet discharge head and an ink jet recording apparatus.
[0002]
[Prior art]
2. Description of the Related Art An ink jet recording apparatus used as an image recording apparatus (image forming apparatus) such as a printer, a facsimile, a copying apparatus, and a plotter includes a nozzle for ejecting ink droplets and an ink flow path (ejection chamber, pressure chamber, pressurizing chamber) communicating with the nozzle. A liquid chamber, a liquid chamber, an ink chamber, etc.) and a driving unit for pressurizing the ink in the ink flow path are mounted with an inkjet head as a droplet discharge head. The droplet discharge head includes, for example, a droplet discharge head that discharges a liquid resist as droplets, a droplet discharge head that discharges a DNA sample as droplets, and the like, but the following description will focus on an inkjet head.
[0003]
It is effective to increase the number of nozzles in such an ink jet recording apparatus in order to achieve multicolor, higher image quality, and higher speed. However, simply increasing the number of nozzles increases the size of the head, This causes a cost increase. Therefore, it is necessary to increase the number of nozzles by increasing the degree of integration of the head itself, while preventing the head from becoming large.
[0004]
By the way, the ink jet head is of a thermal type in which bubbles are generated by heat of vaporization in the liquid chamber, and a diaphragm constituting the wall of the liquid chamber is deformed by using an electromechanical transducer such as a piezoelectric material to generate a pressure in the liquid chamber. The piezo-type which generates phenomena is well known.
[0005]
Among these, the latter piezo type head has a large degree of freedom in ink selection and can control the size of ejected droplets freely by precisely controlling the internal pressure, which is advantageous for high image quality. is there. However, since the structure is more complicated than that of the thermal type head, integration is limited, and one of the factors that hinders the integration is an increase in the density of the diaphragm.
[0006]
That is, as shown in FIG. 9, a general ink-jet head using a laminated piezoelectric body is formed by laminating and joining a flow path plate forming a liquid chamber partition 201, a nozzle plate 203 forming a nozzle 202, and a vibration plate 204. Then, a liquid chamber (pressure chamber) 205 communicating with the nozzle 202 is formed, a thick portion 206 and a thin portion 207 around the thick portion 206 are formed on the vibration plate 205, and the laminated piezoelectric element is formed on the thick portion 206. The pressure in the liquid chamber 205 is changed by driving the piezoelectric element 201 by abutting and joining 210, and the ink is ejected from the nozzle 202.
[0007]
Here, as a method for manufacturing such a diaphragm, for example, a method using electroforming is known as described in JP-A-6-143573. The process of manufacturing a diaphragm by electroforming will be described with reference to FIG.
[0008]
A first layer 212 forming a thin portion 208 is formed on an electroformed support substrate 211 as shown in FIG. 7A, and a portion corresponding to a portion between the thick portions 207 is a window 213 as shown in FIG. By forming a resist pattern 214 and performing nickel electroforming, for example, nickel is deposited and deposited on the first layer 212 to form a nickel layer 215 as shown in FIG. By continuing the casting, as shown in FIG. 9D, when the nickel layer 215 grows until it protrudes from the window 213, the edge effect enlarges also in the surface direction of the patterns 214, 214 to generate an overhang portion 215a. . When this process is continued, the nickel layer 215 further extends in the thickness direction and the plane direction as shown in FIG. 9E, and after the electroforming is completed at a predetermined growth stage, the pattern 214 is removed. As a result, as shown in FIG. 7F, a diaphragm having a stud-shaped island-shaped thick portion 206 surrounded by the concave portion 216 is obtained.
[0009]
[Problems to be solved by the invention]
By using the method for manufacturing a diaphragm as described above, a thin portion and a thick portion of the diaphragm can be manufactured in the same process. In addition, photolithography can be used to form a pattern in a thick portion, and high pattern accuracy can be expected.
[0010]
However, in consideration of handling as a part, the thick portion needs to have a certain thickness or more, and it is inevitable that the overhang 215a occurs. For this reason, when the interval between the patterns 214 is reduced, the overhang shapes overlap, which limits the miniaturization.
[0011]
Further, if the distance between overhangs is reduced for miniaturization, there is a disadvantage that the resist cannot be completely removed and remains in the overhang portion when the resist pattern is removed.
[0012]
Furthermore, since the overhang length is relatively long with respect to the distance between the overhangs, if a pinhole or the like has occurred in the thin portion under the overhang, it cannot be detected, and the reliability of the parts cannot be improved. Is less effective.
[0013]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a droplet discharge head including a highly reliable diaphragm that enables high integration of a head, and an inkjet recording apparatus including the droplet discharge head. The purpose is to provide.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, in a droplet discharge head according to the present invention, a diaphragm has a thick portion with which a driving unit contacts, and a thin portion around the thick portion, and the thick portion has a pattern. The edge portion has an overhang shape of at least two stages with respect to the thin portion, and the total thickness of the thin portion and the thick portion is 10 μm or more.
[0015]
In the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts, and a thin portion around the thick portion, and the thick portion has a pattern edge portion with respect to the thin portion. The angle from the point of contact with the thin portion in the first overhang portion from the thin portion to the point of the overhang surface facing the contact is at least two steps or more, as viewed from the top of the thin portion. Is 5 ° or more.
[0016]
In the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts, and a thin portion around the thick portion, and the thick portion has a pattern edge portion with respect to the thin portion. At least two or more overhangs are formed, and the distance between the first overhangs of adjacent thick portions is 15 μm or more.
[0017]
In the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts, and a thin portion around the thick portion, and the thick portion has a pattern edge portion with respect to the thin portion. At least two or more steps of overhang shape, and the angle of a tangent drawn from the thin part to the upper part of the opposing thick part from the first overhang part is 45 ° or less when viewed from the top of the thin part. It is what it was.
[0018]
An ink jet recording apparatus according to the present invention is equipped with an ink jet head, which is a droplet discharge head according to the present invention.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. An embodiment of an ink jet head which is a droplet discharge head according to the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of a main part of the head along the short side direction of the diaphragm.
[0020]
The ink jet head forms a liquid chamber 6 with which the nozzles 4 communicate by joining the flow path plate 1 having the liquid chamber spacing wall 1a, the vibration plate 2, and the nozzle plate 3 on which the nozzles 4 are formed. Although not shown, a common liquid chamber for supplying ink to the liquid chamber 6 via a fluid resistance portion is formed.
[0021]
On the outer surface side of the vibration plate 2, a laminated piezoelectric element 7 as an electromechanical conversion element which is a driving means (actuator means) for deforming the vibration plate 2 to pressurize the ink in the liquid chamber 6 and a support portion 8 is provided. The other ends of the piezoelectric element 7 and the support 8 are joined to the substrate 9.
[0022]
Here, the flow path plate 1 is formed by, for example, anisotropically etching a single crystal silicon substrate having a crystal plane orientation (110) using an alkaline etching solution such as an aqueous potassium hydroxide solution (KOH) to form a liquid chamber 6 or the like. Although the flow path pattern is formed, it is not limited to a single crystal silicon substrate, and other stainless steel substrates, photosensitive resins, and the like can be used.
[0023]
The diaphragm 2 is formed from a nickel metal plate, and is manufactured by, for example, an electroforming method (electroforming method). The diaphragm 2 has a thin portion 11 for facilitating deformation and a thick portion 12 for contacting and joining the piezoelectric element 7 at a portion corresponding to the liquid chamber 16 and a portion corresponding to the partition wall 1a. Also, a thick portion 12 is formed, the flat surface side is bonded to the flow path plate 1 with an adhesive, the thick portion 12 is bonded to the piezoelectric element 7 with an adhesive, and another thick portion 12 is formed on the support portion 8. Bonded with adhesive. Note that the support portion 8 is formed in the same manner as the piezoelectric element 7, but functions as a simple support since no drive voltage is applied. Details of the structure of the diaphragm 2 will be described later.
[0024]
The nozzle plate 3 forms a nozzle 4 having a diameter of 10 to 30 μm corresponding to each liquid chamber 6, and is bonded to the flow path plate 1 with an adhesive. The nozzle plate 3 may be made of a metal such as stainless steel or nickel, a combination of a metal and a resin such as a polyimide resin film, silicon, or a combination thereof. A water-repellent film is formed on the nozzle surface (surface in the discharge direction: discharge surface) by a well-known method such as a plating film or a water-repellent agent coating in order to ensure water repellency with ink.
[0025]
The piezoelectric element 7 is a laminated piezoelectric element (here, PZT) in which piezoelectric materials 9a and internal electrodes 9b are alternately laminated. In this embodiment, the ink in the liquid chamber 6 is pressurized using the displacement of the piezoelectric element 7 in the direction d33 as the piezoelectric direction.
[0026]
In the ink jet head configured as described above, by selectively applying a driving pulse voltage of 20 to 50 V to the piezoelectric element 7, the piezoelectric element 7 to which the pulse voltage is applied extends in the laminating direction, and 2 is deformed in the direction of the nozzle 4, the ink in the liquid chamber 6 is pressurized by the volume / volume change of the liquid chamber 6, and an ink droplet is ejected (ejected) from the nozzle 4.
[0027]
Then, the liquid pressure in the liquid chamber 6 decreases as the ink droplets are ejected, and a slight negative pressure is generated in the liquid chamber 6 due to the inertia of the ink flow at this time. In this state, when the application of the voltage to the piezoelectric element 7 is turned off, the diaphragm 2 returns to the original position and the liquid chamber 6 has the original shape, so that a further negative pressure is generated. At this time, ink is filled into the liquid chamber 16 from the common liquid chamber. Then, after the vibration of the ink meniscus surface of the nozzle 4 is attenuated and stabilized, a pulse voltage is applied to the piezoelectric element 7 to discharge the next ink droplet, and the ink droplet is discharged.
[0028]
The method of driving the head is not limited to the above-described example (pushing), but pulling or pulling-pushing may be performed according to a driving waveform.
[0029]
Therefore, the details of the structure of the diaphragm 2 will be described with reference to FIGS.
The pattern edge portion of the thick portion 12 of the diaphragm 2 has an overhang shape having two-stage overhang portions 12a and 12b. Here, FIG. 2 is an enlarged view of the thick portion 12 of the diaphragm 2, and FIG. 3 is an enlarged view of a portion A in FIG.
[0030]
The thick portion 12 has a pattern edge portion having a two-stage overhang shape with respect to the thin portion 11, and the total thickness T of the thin portion 11 and the thick portion 12 is 10 μm or more, and in this example, 27 μm.
[0031]
As described above, by setting the thickness of the thick portion 12 to 10 μm or more, it is possible to ensure the handleability of a single component, and to reduce the overhang length d by forming a two-stage overhang shape. Therefore, the distance between the thick patterns can be reduced, and the high integration of the head can be achieved.
[0032]
The dimensions of other parts in this example are overhang length d = 9, overhang height e = 3, thick part width g = 40, and thin part width f = 40 (all units are μm). .
[0033]
In addition, a tangent line 21 between the point c where the thin portion 11 contacts the thin portion 11 and the contact c of the overhang surface and the point a facing the portion a in the first overhang portion 12a from the thin portion 11 is the thin portion 11 of the diaphragm 2. The angle θ1 formed with the upper surface is 5 ° or more, and is approximately 18 ° in this example.
[0034]
As described above, the angle from the point where the first portion of the overhang portion contacts the thin portion to the point where the overhang surface faces the contact point is 5 ° or more when viewed from the top of the thin portion (θ1 = 5). ° or more), it is possible to secure the resist strippability at the time of component production, and further to indirectly illuminate between the overhang portion and the thin portion. For example, when the portion 22 has a pinhole However, by illuminating the diaphragm 2 at an angle of about 45 ° from the side of the thick portion 12, the diaphragm 2 can be observed from the opposite side (flat side), and the thin portion 11 serving as a shadow of the overhang portion 12 a can be observed. Inspection can be performed without missing the pinhole, and the reliability is improved.
[0035]
Further, the distance h between the first-stage overhang portions 12a between the adjacent thick portions 12, 12 is 15 μm or more, and is 22 μm in this example.
[0036]
In this way, by keeping the distance h between the first-stage overhang portions 12a between the adjacent thick portions 12, 12 at an interval of 15 μm or more, it is possible to ensure the resist peeling property at the time of manufacturing the diaphragm. , Reliability is improved.
[0037]
Furthermore, the angle θ2 formed by the tangent line 23 extending from the thin portion 11 to the upper portion b of the thick portion 12 facing from the first-stage overhang portion 12a to the upper surface of the thin portion 11 of the diaphragm 2 is 45 ° or less. Is 34 °.
[0038]
As described above, in the pinhole inspection of the thin portion 11, it is preferable to illuminate at an angle of about 45 °, but when the angle θ2 becomes larger than 45 °, the thin portion 11 And the pinhole inspection becomes insufficient. Therefore, even in the case of a multi-stage overhang shape, the angle of a tangent drawn from the thin portion to the upper portion of the opposing thick portion from the first-stage overhang portion is 45 ° or less when viewed from the top of the thin portion (θ2 = 45 °). By doing so, a pinhole inspection can be performed, and a highly reliable diaphragm can be manufactured.
[0039]
Next, an example of a manufacturing process of the diaphragm will be described with reference to FIGS.
First, as shown in FIG. 4A, a Ti42 film is formed as a conductive layer to a thickness of 100 nm as a conductive layer on the main plane side of the silicon substrate 41 by sputtering, and then Ni43 is formed to a thickness of 3 μm on the Ti42 by electrolytic plating.
[0040]
Thereafter, as shown in FIG. 3B, a resist pattern 44 is formed on the Ni film 43 by photolithography in a portion to be a thin portion. The resist used was a commonly used novolak-based positive resist having a thickness of 3 μm.
[0041]
Next, as shown in FIG. 3C, a Ni film 45 is formed to a thickness of 12 μm by using electrolytic plating. At this time, since the resist thickness is 3 μm, the amount of overhang of the Ni film 45 to be a thick portion is 9 μm obtained by subtracting the resist thickness from the deposition thickness.
[0042]
Further, as shown in FIG. 4D, a resist pattern 46 is formed by using photolithography. The resist pattern 46 is designed to overlap the resist pattern 44 by 3 μm on the outside. Accordingly, the pattern 46 can be surely maintained in an overlapping positional relationship with the pattern 44 even when the misalignment between the masks and the variation in the finished pattern are considered. The resist used was a commonly used novolak-based positive resist having a thickness of 3 μm.
[0043]
Next, as shown in FIG. 5A, a 12 μm thick Ni film 47 is formed using electrolytic plating. At this time, since the resist thickness is 3 μm, the amount of overhang of the Ni film 47 to be a thick portion is 9 μm obtained by subtracting the resist thickness from the deposition thickness. At this time, since the resist pattern 46 has a positional relationship overlapping with the resist pattern 44, the side surface portion of the pattern of the Ni film 47 which is to be a thick portion is surely formed in a two-stage overhang shape. it can.
[0044]
After that, the resist patterns 46 and 44 are peeled off as shown in FIG. Since the distance between adjacent overhangs (distance h in FIG. 3) is maintained at 15 μm or more, and the angle θ1 in FIG. 3 is 15 ° or more, sufficient stripping liquid is applied to the resist under the overhangs. And the resist can be stripped off.
[0045]
Then, as shown in FIG. 3C, the diaphragm member having the thick portion 12 having a two-stage overhang shape is obtained by peeling off the Ni film from the interface with Ti42. In this way, it is possible to manufacture a diaphragm that can be densified using electroforming.
[0046]
Next, an outline of a pinhole inspection method for the thin portion 11 of the diaphragm 2 will be described with reference to FIG. The inspection light 51 is illuminated on the convex surface (the surface on which the thick portion 12 is formed) of the diaphragm 2 from at least 45 degrees with respect to the main surface from at least two directions. On the other hand, the photodetector 52 is disposed on the rear surface side (flat surface side) of the convex portion of the diaphragm.
[0047]
As a result, if a pinhole exists in the thin portion 11, the inspection light 51 leaks to the rear surface side via the pinhole, whereby the presence or absence of the pinhole can be detected, and a reliable inspection can be performed. Thus, a highly reliable diaphragm can be obtained.
[0048]
Next, an example of an ink-jet recording apparatus equipped with an ink-jet head which is a droplet discharge head according to the present invention will be described with reference to FIGS. 7 is an explanatory perspective view of the recording apparatus, and FIG. 8 is an explanatory side view of a mechanism of the recording apparatus.
[0049]
The inkjet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 111, a recording head including the inkjet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper cassette (or a paper tray) 114 capable of loading a large number of sheets 113 from the front side is detachably attached to a lower portion of the apparatus main body 111. The manual feed tray 115 for manually feeding the paper 113 can be opened, and the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in. After the image is recorded, the sheet is discharged to a sheet discharge tray 116 mounted on the rear side.
[0050]
The printing mechanism 112 holds a carriage 123 slidably in the main scanning direction with a main guide rod 121 and a sub guide rod 122, which are guide members laterally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk). A head 124 composed of an ink jet head, which is a liquid droplet discharge head according to the present invention, which discharges ink droplets of each color, mainly includes a plurality of ink discharge ports. They are arranged in a direction crossing the scanning direction, and are mounted with the ink droplet ejection direction facing downward. Each ink cartridge 125 for supplying each color ink to the head 124 is exchangeably mounted on the carriage 123. Note that a head-integrated ink cartridge can also be used.
[0051]
The ink cartridge 125 has an upper air port that communicates with the atmosphere, a lower supply port for supplying ink to the inkjet head, and a porous body filled with ink inside. Maintains the ink supplied to the inkjet head at a slight negative pressure.
[0052]
Further, although the heads 124 of each color are used as the recording heads here, a single head having nozzles for ejecting ink droplets of each color may be used.
[0053]
Here, the carriage 123 is slidably fitted on the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the front guide rod 122 on the front side (upstream side in the paper conveyance direction). are doing. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a drive pulley 128 and a driven pulley 129 which are driven to rotate by a main scanning motor 127. , And the carriage 123 is reciprocally driven by forward and reverse rotation of the main scanning motor 127.
[0054]
On the other hand, in order to convey the paper 113 set in the paper feed cassette 114 to the lower side of the head 124, the paper 113 is guided by a paper feed roller 131 and a friction pad 132 for separating and feeding the paper 113 from the paper feed cassette 114. A guide member 133, a transport roller 134 that transports the fed paper 113 in a reversed state, a transport roller 135 pressed against the peripheral surface of the transport roller 134, and a leading end that defines an angle at which the paper 113 is fed from the transport roller 134. A roller 136 is provided. The transport roller 134 is driven to rotate by a sub-scanning motor 137 via a gear train.
[0055]
Further, an image receiving member 139 is provided as a paper guide member for guiding the paper 113 sent from the transport roller 134 below the recording head 124 in accordance with the movement range of the carriage 123 in the main scanning direction. On the downstream side of the printing receiving member 139 in the paper transport direction, there are provided a transport roller 141 and a spur 142 which are driven to rotate to transport the paper 113 in the paper discharge direction. Rollers 143 and spurs 144 and guide members 145 and 146 forming a paper discharge path are provided.
[0056]
At the time of recording, the recording head 124 is driven in accordance with an image signal while moving the carriage 123, thereby ejecting ink to the stopped paper 113 to record one line, and after transporting the paper 113 by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 113 has reached the recording area, the recording operation is terminated and the sheet 113 is discharged. In this case, the inkjet head according to the present invention, which forms the head 124, has improved controllability of ink droplet ejection and suppresses characteristic fluctuation, so that an image of high image quality can be stably recorded.
[0057]
In addition, a recovery device 147 for recovering the ejection failure of the head 124 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 123. The recovery device 147 has a cap unit, a suction unit, and a cleaning unit. The carriage 123 is moved to the recovery device 147 side during printing standby, the head 124 is capped by the capping means, and the ejection port is kept in a wet state, thereby preventing ejection failure due to ink drying. In addition, by discharging ink that is not related to printing during printing or the like, the ink viscosity of all the discharge ports is kept constant, and stable discharge performance is maintained.
[0058]
In the event of a discharge failure, for example, the discharge port (nozzle) of the head 124 is sealed by a capping unit, and air bubbles and the like are sucked out of the discharge port by a suction unit through a tube, and ink or dust adhered to the discharge port surface. Is removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.
[0059]
As described above, since the inkjet recording apparatus is equipped with the inkjet head having the highly reliable diaphragm with high integration according to the present invention, high-quality recording is possible.
[0060]
In the above embodiment, the droplet discharge head according to the present invention is applied to an inkjet head. However, droplets of liquid other than ink, for example, a droplet discharge head for discharging a liquid resist for patterning, a gene analysis sample, The present invention can also be applied to a droplet discharging head for discharging.
[0061]
【The invention's effect】
As described above, according to the droplet discharge head according to the present invention, the diaphragm has the thick portion where the driving means abuts and the thin portion surrounding the thick portion, and the thick portion has the pattern. Since the edge portion has an overhang shape of at least two steps with respect to the thin portion and the total thickness of the thin portion and the thick portion is 10 μm or more, high integration can be achieved. it can.
[0062]
According to the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts and a thin portion around the thick portion, and the pattern portion of the thick portion is a thin portion. On the other hand, the angle from the point of contact with the thin portion at the first stage overhang portion from the thin portion to the point of the overhang surface facing the contact is at least two stages or more overhang shape. As a result, the configuration is 5 ° or more, so that high integration and improvement in reliability can be achieved.
[0063]
According to the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts and a thin portion around the thick portion, and the pattern portion of the thick portion is a thin portion. On the other hand, since the overhang shape has at least two or more stages and the distance between the first overhang portions of the adjacent thick portions is 15 μm or more, high integration and improvement in reliability are achieved. Can be planned.
[0064]
According to the droplet discharge head according to the present invention, the diaphragm has a thick portion with which the driving means abuts and a thin portion around the thick portion, and the pattern portion of the thick portion is a thin portion. On the other hand, the angle of the tangent drawn from the thin portion to the upper portion of the opposing thick portion from the first overhang portion is 45 ° or less when viewed from the upper surface of the thin portion. With a certain configuration, high integration and improvement in reliability can be achieved.
[0065]
Since the inkjet recording apparatus according to the present invention includes the droplet discharge head according to the present invention that discharges ink droplets, high quality recording can be achieved.
[Brief description of the drawings]
FIG. 1 is an explanatory cross-sectional view taken along a lateral direction of a diaphragm showing an embodiment of an ink-jet head which is a droplet discharge head according to the present invention. FIG. 2 is an enlarged explanatory view of a main part of a diaphragm of the head. FIG. 4 is an enlarged explanatory view of a portion A in FIG. 2; FIG. 4 is a sectional explanatory view illustrating an example of a manufacturing process of the diaphragm; FIG. 5 is a sectional explanatory view illustrating a step following FIG. 4; FIG. 7 is a perspective view showing an example of an ink jet recording apparatus according to the present invention. FIG. 8 is a side view showing a mechanism of the recording apparatus. FIG. FIG. 10 is an explanatory cross-sectional view illustrating a main part. FIG. 10 is an explanatory cross-sectional view illustrating a manufacturing process of a conventional diaphragm.
DESCRIPTION OF SYMBOLS 1 ... Flow path plate, 1a ... Partition wall, 2 ... Vibration plate, 3 ... Nozzle plate, 4 ... Nozzle, 6 ... Liquid chamber, 7 ... Piezoelectric element, 8 ... Support part, 11 ... Thin part, 12 ... Thick part, 12a: Overhang portion.

Claims (5)

A liquid droplet discharger comprising: a deformable vibration plate forming at least one wall surface of a liquid chamber to which a nozzle for discharging liquid droplets communicates; and a drive unit for deforming the vibration plate to change the pressure in the liquid chamber. In the head, the diaphragm has a thick portion with which a driving unit is in contact, and a thin portion around the thick portion, and the thick portion has at least two steps of pattern edge portions with respect to the thin portion. Wherein the total thickness of the thin portion and the thick portion is 10 μm or more. A liquid droplet discharger comprising: a deformable vibration plate forming at least one wall surface of a liquid chamber to which a nozzle for discharging liquid droplets communicates; and a drive unit for deforming the vibration plate to change the pressure in the liquid chamber. In the head, the diaphragm has a thick portion with which a driving unit is in contact, and a thin portion around the thick portion, and the thick portion has at least two steps of pattern edge portions with respect to the thin portion. And the angle from the point of contact with the thin portion in the first overhang portion from the thin portion to the point of the overhang surface facing the contact is 5 ° as viewed from the top of the thin portion. A droplet discharge head characterized by the above. A liquid droplet discharger comprising: a deformable vibration plate forming at least one wall surface of a liquid chamber to which a nozzle for discharging liquid droplets communicates; and a drive unit for deforming the vibration plate to change the pressure in the liquid chamber. In the head, the diaphragm has a thick portion with which a driving unit is in contact, and a thin portion around the thick portion, and the thick portion has at least two steps of pattern edge portions with respect to the thin portion. Wherein the distance between the first-stage overhang portions of adjacent thick portions is 15 μm or more. A liquid droplet discharger comprising: a deformable vibration plate forming at least one wall surface of a liquid chamber to which a nozzle for discharging liquid droplets communicates; and a drive unit for deforming the vibration plate to change the pressure in the liquid chamber. In the head, the diaphragm has a thick portion with which a driving unit is in contact, and a thin portion around the thick portion, and the thick portion has at least two steps of pattern edge portions with respect to the thin portion. And the angle of a tangent drawn from the thin portion to the upper portion of the thick portion facing from the first overhang portion is 45 ° or less when viewed from the top of the thin portion. Droplet discharge head. An inkjet recording apparatus comprising an inkjet head for ejecting ink droplets, wherein the inkjet head is the droplet ejection head according to any one of claims 1 to 4.

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