JP2006095891A - Liquid discharge head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional SiN film formed on the surface of a silicone top plate by a pressure reduction CVD method has no good follower characteristic to fine unevenness, and that defect parts on the surface of the top plate are hard to be completely coated with the SiN film, causing the liquid flowing along the SiN film to generate disturbance at the defect parts to deteriorate smooth flow of the liquid. <P>SOLUTION: The liquid discharge head comprises a substrate 37 provided with a discharge energy generating part 16 for discharging liquid at specified intervals, a partition member 38 having a partition wall 41 arranged so as to partition individual discharge energy generating parts 16, and a silicone top plate 40 having a liquid supply hole 39 supplied with fluid on the base end side. The top plate 40 is overlapped on the substrate 37, holding the partition member 38 in between, to be bonded to the partition member 38. Thereby, the liquid discharge head, wherein a flow passage 21 that allows the tip end side to be communicated with discharge ports 22 and the base end side to be communicated with the liquid supply port 39 is formed, has the top plate 40 the surface of which is covered with a protective film 45 made of a silicon dioxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid discharge head that discharges liquid and a method of manufacturing the liquid discharge head.

  The “print” described in this specification is not only for forming significant information such as characters and figures, but also manifested so that it can be perceived visually by humans, regardless of significance. Regardless of whether or not it is, it includes a case where an image, a pattern, a pattern or the like is widely formed on the print medium, or the print medium is processed such as etching.

  The “print medium” is a sheet-like object that can accept not only a piece of paper used in a general printing apparatus but also a liquid such as a cloth, a resin film, a metal plate, glass, ceramics, wood, and leather. Other three-dimensional solids such as a sphere and a cylinder are also included.

  Furthermore, “liquid” is to be interpreted widely as the definition of “print” above, and by being applied on the print medium, the formation of images, patterns, patterns, etc., processing of the print medium such as etching, Alternatively, it refers to a liquid that can be subjected to ink processing, such as solidification or insolubilization of the colorant in the ink applied to the print medium, and includes any liquid used for printing.

  Ink-jet liquid discharge methods that are widely used today include the generation of discharge energy that is used to discharge liquids such as ink and processing liquids for adjusting the printability of the inks on print media. There are known a method using an electrothermal transducer (heater) as a device and a method using a piezoelectric device (piezo), both of which can control ejection of droplets by an electrical signal. . More specifically, the principle of the droplet discharge method using an electrothermal transducer is that an electric signal is given to the electrothermal transducer to instantaneously boil the liquid near the electrothermal transducer, and the liquid at this time In other words, droplets are ejected from the ejection port at a high speed by the rapid bubble growth caused by the phase change of the gas. On the other hand, the principle of the droplet discharge method using the piezoelectric element is that the piezoelectric element is displaced by giving an electric signal to the piezoelectric element, and the droplet is discharged from the discharge port by the pressure at the time of the displacement.

  The one using an electrothermal transducer does not require much space for the discharge energy generating element, has a simple liquid discharge head (inkjet head) structure, and is easy to integrate discharge ports. There is. However, the inherent disadvantage of using this electrothermal transducer is that the volume of the flying droplets due to heat accumulation in the inkjet head, such as the heat generated by the electrothermal transducer, or the electrothermal conversion of cavitation due to defoaming There are effects on the body. For example, a substrate on which ejection energy generation units for ejecting liquid droplets are provided at predetermined intervals, a partition member having partition walls arranged so as to partition individual ejection energy generation units, and a liquid supply to which liquid is supplied In an inkjet head having a top plate having a hole on the base end side, when the top plate is formed of a silicon wafer in order to form the liquid supply hole of the top plate by anisotropic etching, acidic liquid or alkaline It is necessary to form a protective film against the liquid on the surface.

Conventionally, when using silicon wafer as the material of the ink jet head, low pressure chemical vapor deposition as a protective film (LPCVD: L ow P ressure C hemical V apor D eposition) process silicon nitride film formed by (hereinafter, SiN film) Is generally disclosed, for example, in Patent Document 1.

JP 2000-198199 A

  Since the SiN film formed on the surface of the silicon wafer by the gas phase reaction method such as the LPCVD method (hereinafter referred to as the low pressure CVD method) does not have a good followability to the fine irregularities, the SiN film has a crack on the surface of the silicon wafer. When there is a defect such as this, it becomes difficult to completely cover this portion with the SiN film, and there is a possibility that the silicon is corroded by the liquid from the portion where the surface of the silicon is exposed.

  Such a state is schematically shown in FIG. If the crack 2 exists on the surface of the silicon 1, the SiN film 3 cannot cover the portion of the crack 2, and the crack 2 is exposed to the outside. The liquid flowing along the SiN film 3 causes a turbulent flow in the crack 2 part, and the flow of the smooth liquid is impaired. The crack 2 part is eroded by the liquid, and the corrosion of the crack 2 part is caused. As a result of the progressive progress, the smooth flow of the liquid may be further impaired.

  An object of the present invention is to provide a liquid discharge head having a silicon top plate on which a protective film excellent in followability to surface defects is formed, and a method for manufacturing the same.

  According to a first aspect of the present invention, there is provided a substrate on which ejection energy generation units for ejecting liquid droplets are provided at predetermined intervals, and a partition member having a partition wall arranged so as to partition each of the ejection energy generation units. A top plate made of silicon having a liquid supply hole to which liquid is supplied on the base end side, the top plate is overlapped with the substrate with the partition member interposed therebetween, and the distal end side is joined to the partition member A liquid discharge head in which a liquid passage is formed which communicates with the discharge port and has a base end which communicates with the liquid supply hole. The top plate is covered with a protective film made of silicon dioxide. It is what.

  In the present invention, the liquid is supplied from the liquid supply hole of the top plate made of silicon, and the liquid interposed in the liquid passage is discharged as droplets from the discharge port by the operation of the discharge energy generating unit. The surface of the top plate that discharges liquid droplets from the discharge port through the liquid path corresponding to the discharge energy generating part is covered with a protective film made of silicon dioxide that has fewer defects than silicon nitride. Corrosion is prevented, and a smooth flow of the liquid in the liquid channel can be maintained.

  In the liquid discharge head according to the first aspect of the present invention, a common liquid chamber communicating with the liquid supply hole and the liquid path can be formed, and the top plate can be formed of a single crystal silicon wafer. it can.

  According to a second aspect of the present invention, there is provided a substrate on which ejection energy generating parts for ejecting droplets are provided at predetermined intervals, and a partition member having a partition wall arranged so as to partition each of the ejection energy generating parts. A top plate made of silicon having a liquid supply hole for supplying a liquid on the base end side, and the top plate communicates with the discharge port by overlapping the top plate on the substrate with the partition member interposed therebetween. A method of manufacturing a liquid discharge head in which a liquid path whose end side communicates with the liquid supply hole is formed, wherein the liquid supply hole is formed by performing anisotropic etching from both surfaces of a single crystal silicon wafer; Forming a top plate by forming a protective film of silicon dioxide on the surface of the single crystal silicon wafer in which the supply hole is formed by a liquid phase deposition method; and partitioning the top plate on which the protective film is formed Across the member superposed on the substrate, in which equipped with a step of bonding the partitioning member.

In the present invention, masking is performed on both surfaces of the single crystal silicon wafer except for the portion serving as the liquid supply hole, and anisotropic etching is performed on the single crystal wafer in this state. Thus, after forming the liquid supply hole in a portion masking of the single crystal silicon wafer is not present, the single crystal silicon wafer of surface liquid phase deposition (LPD: L iquid P hase D eposition) protection silicon dioxide by method film Form. A liquid ejection head is obtained by stacking the top plate manufactured in this manner on the substrate with the partition member interposed therebetween, and joining the top plate and the partition member.

  In the method for manufacturing a liquid ejection head according to the second aspect of the present invention, a step of forming ejection energy generating portions on the surface of the substrate at predetermined intervals, and a partition member on the surface of the substrate on which the ejection energy generating portions are formed. And the step of forming the partition member on the surface of the substrate may include the step of forming in the partition member a void portion serving as a common liquid chamber communicating with the liquid passage and the liquid supply hole.

  The step of forming the protective film on the surface of the single crystal silicon wafer may include the step of immersing the single crystal silicon wafer in an aqueous hydrofluoric acid solution containing silicon dioxide in supersaturation.

  The present invention includes an ink jet system that includes means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used for discharging a liquid, and causes a change in the state of the liquid by the thermal energy. In this liquid discharge head, an excellent effect is brought about. This is because according to such a method, high density and high definition of the print can be achieved.

  The present invention can also be effectively applied to a full-line type liquid discharge head having a length corresponding to the maximum width of a print medium that can be printed by the image forming apparatus. As such a liquid discharge head, either a configuration satisfying the length by a combination of a plurality of liquid discharge heads or a configuration as a single liquid discharge head formed integrally may be used. Even if the carriage is of a serial type in which the carriage scans along the width direction of the print medium, the carriage can be replaced by being mounted on the carriage in a replaceable manner or with a liquid discharge head that is integrally fixed to the carriage. A replaceable chip-in type head cartridge that can be electrically connected to and supplied from the apparatus main body, or a head cartridge in which a liquid storage head is provided with a tank that stores liquid in an integrated or replaceable manner The present invention is also effective when using.

  As for the type and number of liquid ejection heads mounted on the image forming apparatus, for example, only one type corresponding to a single color ink is provided, and other types of inks having different hues and densities (lightness) are used. Correspondingly, a plurality of them may be provided. That is, for example, the print mode of the image forming apparatus is not limited to a print mode of only a mainstream color such as black, but the liquid discharge head may be configured integrally or a plurality of combinations. The present invention is also very effective for an image forming apparatus having at least one of full-color print modes using color or mixed colors. In this case, it is also effective to discharge a processing liquid (printability improving liquid) for adjusting the printability of ink according to the type of print medium and the print mode from a dedicated or common liquid discharge head to the print medium.

  The image forming apparatus using the liquid discharge head according to the present invention is used as an output terminal of an information processing device such as a computer or an optical disk device, a copying apparatus combined with a reader, and further has a transmission / reception function. It may be in the form of a facsimile machine, a textile printing machine, or an etching machine. The print medium may be a sheet or long paper or cloth, or a plate-like wood or leather, stone, resin or glass. In addition to metal and the like, a three-dimensional structure can be used.

  According to the liquid discharge head of the present invention, since the surface of the silicon top plate is covered with the protective film made of silicon dioxide, it becomes possible to form a dense protective layer with fewer defects than the conventional protective layer made of silicon nitride. The corrosion of the top plate due to the liquid supplied from the liquid supply port of the top plate into the liquid discharge head can be greatly suppressed. As a result, it is possible to use an acidic or alkaline liquid whose pH greatly deviates from 7, and it is possible to improve the durability of the top plate of the liquid discharge head.

  When a common liquid chamber communicating with these is formed between the liquid supply hole and the liquid path, the pulsation of the liquid in the liquid path that occurs when the liquid droplets are discharged from the discharge port is mitigated by the presence of the common liquid chamber. Can be made.

  When the top plate is formed of a single crystal silicon wafer, the liquid supply hole can be easily and accurately formed by anisotropic etching.

According to the method for manufacturing a liquid discharge head of the present invention, a liquid supply hole is formed by performing anisotropic etching from both sides of a single crystal silicon wafer, and a liquid phase deposition method (hereinafter, LPD method) is formed on the surface of the single crystal silicon wafer. After forming a protective film made of silicon dioxide, the top plate obtained by this is superimposed on the substrate with the partition member in between, and integrally joined to the partition member. A dense protective layer with fewer defects than the protective layer made of silicon can be formed on the surface of the top plate. As a result, it becomes possible to use an acidic or alkaline liquid whose pH is greatly different from 7. Thus, a highly reliable liquid discharge head capable of improving the durability of the top plate can be obtained. In particular, the SiO ₂ protective layer formed by the LPD method has a follow-up property to the surface property of the single crystal silicon wafer to be protected as compared with the SiN protective layer formed by the conventional low pressure CVD method. In addition to the excellent smoothness of the surface of the protective layer itself, the fluidity of the liquid is not impaired and the ejection of the liquid from the ejection port can be maintained well.

  Discharge energy generating portions are formed at a predetermined interval on the surface of the substrate, and a partition member is formed on the surface of the substrate. When the partition member is formed on the surface of the substrate, it communicates with the liquid path and the liquid supply hole. When the gap member serving as the common liquid chamber is formed in the partition member, a common liquid chamber communicating with these is formed between the liquid supply hole and the liquid path, and the liquid droplets are discharged from the discharge port. The pulsation of the generated liquid in the liquid path can be mitigated by the presence of the common liquid chamber.

  In order to form a protective film on the surface of the single crystal silicon wafer, when the single crystal silicon wafer is immersed in a hydrofluoric acid aqueous solution containing silicon dioxide in a supersaturated state, a protective film of silicon dioxide is formed on the entire surface of the single crystal silicon wafer. It can be formed easily and uniformly.

  An embodiment in which the liquid discharge head according to the present invention is applied to an ink jet printer will be described in detail with reference to FIGS. 1 to 11. However, the present invention is not limited to such an embodiment, and the scope of the invention is defined in the claims. All changes and modifications encompassed by the described inventive concept are possible and can of course be applied to any other technique belonging to the spirit of the invention.

  The appearance of the ink jet printer in this embodiment is schematically shown in FIG. 1, the appearance of the ink jet head is shown in an exploded state in FIG. 2, and the internal structure is schematically shown in FIG. That is, the ink jet printer 10 according to the present embodiment is a full line type color printer, and has four ink tanks 11Y, 11M, 11C, and 11B that store yellow ink, magenta ink, cyan ink, and black ink, respectively. (Hereinafter collectively referred to as ink tanks 11) and four ink jet heads 13Y, 13M, 13C, 13B (hereinafter referred to as ink tanks 11) connected to the ink tanks 11 via connection pipes 12, respectively. The ink tanks 11 are connected to the connection pipe 12 in a replaceable manner.

  The ink-jet head 13 in which energization of each electrothermal transducer 16 (see FIG. 3) is switched on / off by a head driver 15 connected to the control device 14 faces the platen 18 with an endless transport belt 17 interposed therebetween. As described above, they are arranged at predetermined intervals along the conveying direction of the conveying belt 17. The head moving means 19 for recovery processing whose operation is controlled by the control device 14 can be moved up and down in the direction facing the platen 18. Prior to printing on the print medium 20, the old ink interposed in the ink passage 21 (see FIG. 3) is ejected from the ejection port 22 (see FIG. 3) to the side of each inkjet head 13. A head cap 23 for performing a recovery process is arranged in a state shifted by a half pitch with respect to the arrangement interval of the inkjet heads 13, and cap movement means 24 whose operation is controlled by the control device 14, respectively, immediately below the inkjet head 13. It moves and receives waste ink discharged from the discharge port 22.

  The conveying belt 17 that conveys the print medium 20 is wound around a driving roller 26 connected to a belt driving motor 25, and its operation is switched by a motor driver 27 connected to the control device 14. Further, on the upstream side of the conveying belt 17, a charging device 28 is provided for charging the conveying belt 17 to bring the print medium 20 into close contact with the conveying belt 17. The electrification driver 29 connected to the control device 14 is switched on / off. A pair of paper feed rollers 30 for supplying the print medium 20 onto the transport belt 17 is connected to a paper feed motor 31 for driving and rotating the pair of paper feed rollers 30. The operation of the motor 31 is switched by a motor driver 32 connected to the control device 14.

  Therefore, prior to the printing operation on the print medium 20, the inkjet head 13 is lifted away from the platen 18, and then the head cap 23 is moved directly below the inkjet head 13 to perform the recovery process of the inkjet head 13. The head cap 23 is moved to the original standby position, and the inkjet head 13 is further moved to the platen 18 side to the printing position. At the same time as the charger 28 is operated, the conveying belt 17 is driven, and the print medium 20 is placed on the conveying belt 17 by the paper feed roller 30, and a predetermined color image is printed by each inkjet head 13. 20 is printed.

The ink jet head 13 of this embodiment includes a head chip 33, a printed wiring board for connecting the head chip 33 and electrically by wire bonding using gold wire: and (PWB P rinted W iring B oard ) 34, these head chips 33 and a base plate 35 on which the PWB 34 is mounted, and an ink supply unit 36 that guides ink supplied from the connection pipe 12 to the head chip 33. The head chip 33 is formed on the surface of the heating element substrate 37 on which the above-described electrothermal transducer 16 is formed that gives thermal energy to boil ink and generate bubbles, and to which the PWB 34 is connected. And a top plate 40 which is joined to the heat generating element substrate 37 with the partition member 38 interposed therebetween and has an ink supply hole 39 connected to the connection pipe 12. The partition member 38 partitions the electrothermal converter 16 between the heating element substrate 37 and the top plate 40 to form the ink passage 21 and the ejection port 22, and common ink that communicates with each ink passage 21. A chamber 42 is defined. On the base end side of each ink passage 21, an elastically deformable reed valve 43 is provided for efficiently directing bubbling energy accompanying the boiling of ink toward the discharge port 22. In this embodiment, the partition member 38 is formed of a photosensitive resin, and a silicon dioxide (hereinafter referred to as SiO ₂ ) film 42 is formed as a protective layer on the surface of the top plate 40 formed of silicon 42 by the LPD method. ing. The top plate 40 is patterned by photolithography on both the front and back sides of a silicon wafer and anisotropically etched from both sides to form ink supply holes 39 having a predetermined shape.

FIG. 4 shows an enlarged cross-sectional structure of the top plate 40 in this embodiment. The SiO ₂ film 45 formed on the surface of the silicon 42 by the LPD method is excellent in following the defects 46 such as micro cracks existing on the surface of the silicon 42, so that these defects 46 are completely covered. It is possible to smooth the surface of the plate 40. For this reason, the turbulent flow of the ink flowing therethrough hardly occurs, and the ink can smoothly flow from the ink supply hole 39 toward the ink passage 21 as the ink is discharged from the discharge port 22. Moreover, even if acidic or alkaline ink is used, the durability of the top plate 40 can be remarkably improved because the surface of the top plate 40 is completely covered with the SiO ₂ film 45.

The manufacturing process of the top plate 40 will be described in sequence with reference to FIGS. 5 to 9. The top plate 40 is positively positioned on the surface side of the silicon wafer 48 covered with the thermal oxide film 47, that is, on the surface facing the outside of the head chip 33. A type photoresist 49 is applied by spin coating (see FIG. 5), irradiated with ultraviolet rays through a mask (not shown), and then developed to pattern the positive photoresist 49 (see FIG. 6). Next, the thermal oxide film 47 exposed in the patterned portion is removed by etching (see FIG. 7), but these series of operations are also performed on the back side of the silicon wafer 48, that is, the surface facing the common ink chamber 42. Finally, the positive photoresist 49 is removed, and the patterning of the ink supply hole 39 by the thermal oxide film 47 is completed (see FIG. 8). Thereafter, anisotropic etching is performed on the silicon wafer 48 using the remaining thermal oxide film 47 as a mask to open ink supply holes 39 in the silicon wafer 48 (see FIG. 9). Finally, all the thermal oxide films 47 remaining on both the front and back surfaces of the silicon wafer 48 are removed by etching, and the SiO ₂ film 45 by the LPD method is formed on both the front and back surfaces of the silicon wafer 48. Get 40.

The above-described LPD method is a method for promoting the deposition of the SiO ₂ film 45 by immersing the silicon wafer 48 in an aqueous solution of SiO ₂ supersaturated hydrofluoric acid (hereinafter referred to as H ₂ SiF ₆ ). Is schematically shown in FIG. When the reaction vessel 50 for adding silica gel and aluminum necessary for the reaction and the film formation vessel 51 for film formation by immersing the silicon wafer 48 are used as a common container, impurities generated during the reaction adhere to the silicon wafer. Since the desired SiO ₂ film may not be formed, the film forming apparatus in this embodiment is divided into two tanks, a reaction tank 50 and a film forming tank 51, and these are kept at 35 ° C. 52. The H ₂ SiF ₆ aqueous solution 53 in the reaction tank 50 that has been brought into a supersaturated state of SiO ₂ due to the addition of silica gel and aluminum is sucked up by a circulation pump 54 and has a pore size of 1.0 μm (made by Toyo Roshi Kaisha, Ltd.) 55 and 0 It is filtered by a .1 μm filter (manufactured by Nihon Microlith Co., Ltd.) 56 and returned to the film formation tank 51, where it overflows into the reaction tank 50, and the silicon wafer 48 is immersed in the film formation tank 51. To form a film.

More specifically, 15 g of silica gel (SiO ₂ ) manufactured by Kanto Chemical Co., Inc. is added to 1 liter of an aqueous solution of H ₂ SiF ₆ having a concentration of 14 to 28% at 35 ° C., and completely dissolved. In this case, the chemical equilibrium state is represented by H ₂ SiF ₆ + 2H ₂ O⇔SiO ₂ + 6HF. Then, the SiO ₂ is aluminum manufactured by Kanto Chemical Co., Ltd., a reaction initiator _H 2 SiF ₆ aqueous solution 53 is saturated with 24g turned against _H 2 SiF ₆ aqueous solution 1 liter left for about 12 hours Then, the chemical equilibrium state of the chemical formula described above is shifted in the right direction, that is, the direction in which SiO ₂ precipitates, to obtain a H ₂ SiF ₆ aqueous solution 53 in which SiO ₂ is sufficiently supersaturated. After that, the SiO ₂ supersaturated H ₂ SiF ₆ aqueous solution 53 was circulated for 3 hours using the two-stage filters 55 and 56, and then the silicon wafer 48 was immersed in the film formation tank 51 while continuing this circulation operation. Film formation is performed for a predetermined time.

In this way, the SiO ₂ film 45 is formed silicon wafer 48 surface of ESCA: shows the results of (E lectoron S pectroscopy for C hemical A nalysis Electron Spectroscopy for Chemical Analysis) in Table 1 below.

Here, the sample of Reference Example 1 is a bare wafer having a natural oxide film formed on the surface thereof, and has not been subjected to any treatment for forming a protective film. In all of Examples, Comparative Examples 1 and 2, and Reference Examples, the presence of Si and O was confirmed, but in Examples where aluminum was added in an amount of 24 grams per liter, which was four times that of Reference Examples 1 and 2. The ratio of Si and O was approximately 1: 2, and it was confirmed that the SiO ₂ film was formed on the surface of the silicon wafer as the sample. In addition, as a result of measuring with a film thickness measuring instrument in this example, the SiO ₂ film thickness has reached 1580 mm, so that silicon dioxide in the hydrofluoric acid aqueous solution is supersaturated. It was also confirmed that the added amount of aluminum greatly influenced the SiO ₂ film forming amount.

In the above-described example, a 14% concentration H ₂ SiF ₆ aqueous solution was used. The relationship between the immersion time and the film thickness is shown in FIG. The broken line in FIG. 11 shows the change in the above-described embodiment, but the change when the concentration of the H ₂ SiF ₆ aqueous solution is 28% is shown by the solid line. When immersed in _H 2 SiF ₆ aqueous solution of 28% concentration, the deposition rate of the SiO ₂ is increased to about 150~200Å per hour, the thickness of the SiO ₂ film by the reaction time is LPD method anyway It was confirmed that it can be controlled.

In order to confirm the durability of the SiO ₂ film obtained by the LPD method with respect to a silicon wafer, silicon having a 540 mm SiO ₂ film formed by immersing in a 28% concentration H ₂ SiF ₆ aqueous solution for 3 hours. Using a wafer and a silicon wafer on which a protective layer was not formed, these were immersed for 10 hours in existing weakly alkaline ink heated to 120 ° C. while being pressurized to 2 atm. As a result, the silicon wafer on which the protective layer of the SiO ₂ film was not formed was roughened by the surface being attacked by the ink, but the silicon wafer having the 540 mm SiO ₂ film was completely affected by the ink. No change in the surface state was observed. As a result, it was found that the SiO ₂ film formed by the LPD method is sufficiently resistant to existing ink even when the film thickness is about 500 mm. Even if a strongly alkaline ink appears in the future, it is considered that the silicon top plate can have sufficient resistance by controlling the thickness of the protective layer.

FIG. 3 is a three-dimensional projection view schematically showing an ink jet printer using the liquid discharge head according to the present invention. FIG. 2 is a three-dimensional projection view showing an appearance of an ink jet head mounted on the ink jet printer shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing the structure of the inside of the ink jet head shown in FIG. 2. It is an expanded sectional view of the part of the top plate of the inkjet head shown in FIG. FIG. 10 is a conceptual diagram showing a manufacturing process of the ink jet head shown in FIG. 3 together with FIGS. FIG. 10 is a conceptual diagram showing a manufacturing process of the ink jet head shown in FIG. 3 together with FIGS. 5 and 7 to 9. FIG. 10 is a conceptual diagram showing a manufacturing process of the inkjet head shown in FIG. 3 together with FIGS. 5, 6, 8, and 9. It is a conceptual diagram showing the manufacturing process of the inkjet head shown in FIG. 3 with FIG. 5-FIG. 7, FIG. It is a conceptual diagram showing the manufacturing process of the inkjet head shown in FIG. 3 with FIGS. It is a conceptual diagram of the processing apparatus by LPD method. It is a graph showing the relationship between the immersion time of the silicon wafer by the processing apparatus shown in FIG. 10, and the film thickness of the protective layer formed in the surface. It is an expanded sectional view of a top plate portion in a conventional liquid discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet printer 11Y, 11M, 11C, 11B Ink tank 12 Connection piping 13, 13Y, 13M, 13C, 13B Inkjet head 14 Control device 15 Head driver 16 Electrothermal transducer 17 Conveying belt 18 Platen 19 Head moving means 20 Print medium DESCRIPTION OF SYMBOLS 21 Ink passage 22 Discharge port 23 Head cap 24 Cap moving means 25 Belt drive motor 26 Drive roller 27 Motor driver 28 Charger 29 Charger driver 30 Paper feed roller 31 Paper feed motor 32 Motor driver 33 Head chip 34 Printed wiring board ( PWB)
35 Base plate 36 Ink supply unit 37 Heating element substrate 38 Partition member 39 Ink supply hole 40 Top plate 41 Partition wall 42 Common ink chamber 43 Reed valve 44 Silicon 45 SiO ₂ film 46 Defect 47 Thermal oxide film 48 Silicon wafer 49 Positive photo Resist 50 Reaction tank 51 Deposition tank 52 Constant temperature bath 53 H ₂ SiF ₆ aqueous solution 54 Circulation pump 55, 56 Filter

Claims (6)

A substrate provided with discharge energy generating portions for discharging droplets at predetermined intervals, a partition member having a partition wall arranged so as to partition each of the discharge energy generating portions, and a liquid supply hole for supplying a liquid A top plate made of silicon having a base end side, and the top plate is superimposed on the substrate with the partition member interposed therebetween and joined to the partition member so that the distal end side communicates with the discharge port and the base end side is A liquid discharge head in which a liquid path communicating with the liquid supply hole is formed,
The top of the top plate is covered with a protective film made of silicon dioxide.   The liquid discharge head according to claim 1, wherein a common liquid chamber communicating with the liquid supply hole and the liquid path is formed.   The liquid discharge head according to claim 1, wherein the top plate is formed of a single crystal silicon wafer. A substrate provided with discharge energy generating portions for discharging droplets at predetermined intervals, a partition member having a partition wall arranged so as to partition each of the discharge energy generating portions, and a liquid supply hole for supplying a liquid And a top plate made of silicon having a base end side, and the top plate communicates with the discharge port and the base end side communicates with the liquid supply hole by overlapping the top plate on the substrate with the partition member interposed therebetween. A method of manufacturing a liquid discharge head in which a liquid path is formed,
Performing anisotropic etching from both sides of the single crystal silicon wafer to form a liquid supply hole;
Forming a protective film with silicon dioxide by a liquid phase deposition method on the surface of the single crystal silicon wafer in which the liquid supply hole is formed, and obtaining a top plate;
A method of manufacturing a liquid discharge head comprising: a step of superposing a top plate on which the protective film is formed on the substrate with the partition member interposed therebetween and joining the substrate to the partition member. Forming the discharge energy generating portions on the surface of the substrate at a predetermined interval;
Forming the partition member on the surface of the substrate on which the discharge energy generating unit is formed, and forming the partition member on the surface of the substrate communicates with the liquid path and the liquid supply hole. The method of manufacturing a liquid discharge head according to claim 4, further comprising a step of forming, in the partition member, a gap that becomes a common liquid chamber. 5. The step of forming a protective film on the surface of the single crystal silicon wafer includes the step of immersing the single crystal silicon wafer in an aqueous hydrofluoric acid solution containing silicon dioxide in supersaturation. Item 6. A method for manufacturing a liquid discharge head according to Item 5.

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