JP3842120B2 - Droplet discharge head and inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a droplet discharge head and an ink jet recording apparatus, and more particularly, a processing method for forming a fine shape on a silicon single crystal substrate having a crystal orientation, and a pressurized liquid chamber used for the droplet discharge head. The present invention relates to a processing method and a shape of a silicon single crystal substrate.
[0002]
[Prior art]
The ink jet recording apparatus has many advantages such as extremely low noise during recording, high speed printing, and the ability to use inexpensive plain paper with a high degree of ink freedom. Among them, a so-called ink-on-demand system that discharges ink droplets only when recording is necessary does not require collection of ink droplets that are not necessary for recording, and is currently mainstream. In this ink-on-demand type liquid droplet ejection head, the driving means is a piezoelectric element (Japanese Patent Publication No. 2-51734), or a method of heating ink to generate bubbles and ejecting ink with the pressure. (Japanese Patent Publication No. 61-59911) and those using electrostatic force as driving means (Japanese Patent Laid-Open No. 5-50601). Among these, a droplet discharge head of a type in which a pressure chamber is formed by adhering a nozzle plate having a nozzle opening and a diaphragm to both surfaces of a spacer, and the diaphragm is deformed by a piezoelectric vibrator causes ink droplets to fly. Since heat energy is not used as a drive source for this purpose, it is possible to discharge color ink that is not easily deteriorated by heat and that is particularly susceptible to heat deterioration. Moreover, since the amount of ink in the ink droplets can be freely adjusted by adjusting the displacement amount of the piezoelectric vibrator, it is an optimum head for constructing a printer for high-quality color printing.
[0003]
On the other hand, when performing higher-quality color printing using a droplet discharge head, higher resolution is required. Therefore, the size of the piezoelectric vibrator, spacer member partition walls, and the like is inevitably reduced. High precision is required for processing and assembly of members. For this reason, a droplet discharge head is configured by applying a part manufacturing technology using anisotropic etching of a silicon single crystal substrate capable of processing a fine shape with high accuracy by a relatively simple method, so-called micromachining technology. The processing of members has been studied, and various techniques and methods have been proposed. Since the spacer using single crystal silicon has high mechanical rigidity, it can reduce the deflection of the entire recording head due to the deformation of the piezoelectric vibrator and the etched wall is almost perpendicular to the surface. This has the great advantage that the generation chamber can be configured uniformly.
[0004]
[Problems to be solved by the invention]
However, according to the above conventional example, since etching depends on the crystal orientation, it is difficult to process into an ideal shape as a pressure generating chamber of a droplet discharge head, which easily causes ink stagnation and bubble stagnation. There is a disadvantage that the adhesive at the time of assembling the head flows into the opposite surface of the joint due to the capillary effect. In order to deal with such problems, there is a proposal to eliminate the acute angle portion caused by anisotropic etching and surround it with six faces as disclosed in JP-A-7-178908. Therefore, there is a problem that control is difficult. Further, since it is composed of higher-order surfaces, there is a problem that the surface is rattling and obstructs ink flow.
[0005]
The present invention is for solving these problems, and includes a pressure liquid chamber processed by anisotropic etching of a silicon single crystal substrate having a smooth ink flow and no inflow of an adhesive, and an ink supply port. It was, and to provide a droplet discharge head and an ink jet recording apparatus.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the droplet ejection apparatus of the present invention includes a nozzle member having a nozzle which droplets are ejected, and the communicating pipe is joined to the nozzle formation member, via the communication pipe A pressurizing liquid chamber communicating with the nozzle and a diaphragm for pressurizing the pressurizing liquid chamber are provided. Furthermore, according to the liquid droplet ejection apparatus of the present invention, the communicating pipe and pressurized liquid chamber is formed by anisotropic etching of the silicon single crystal substrate of plane orientation (110), the communicating pipe is a nozzle formed a contact Keru planar shape all edges at the interface between the member a hexagonal contact at an obtuse angle, is parallelogram cross-sectional shape in the extending direction central portion of the joint surface and parallel communication pipe. Therefore, when the nozzle forming member and the pressurized liquid chamber are joined with an adhesive, it is possible to prevent the adhesive from flowing into the communication pipe due to the capillary effect, and therefore, the droplet jetting bend due to the inflow of the adhesive. In addition, since it has a shape in which there is no stagnation of bubbles and there is no stagnation in the flow of ink, it is possible to provide a highly reliable droplet discharge head that is free from jetting down due to bubble retention.
[0007]
In addition, an ink jet recording apparatus as another invention is characterized in that the above-described droplet discharge head is mounted. Therefore, it is possible to provide a highly reliable inkjet recording apparatus using a droplet discharge head that can prevent the adhesive from flowing into the communication pipe and can prevent the stagnation of bubbles. it can.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The droplet discharge head of the present invention eliminates the acute angle portions on the nozzle joint surface side and the diaphragm joint surface side of the substantially parallelogram shape generated by anisotropic etching of silicon, thereby making the shape of the bubble contact by obtuse angle. Smoothing the ink flow by providing an inclined part at a place where stagnation is likely to occur, and when the head is assembled, the adhesive flows into the communication pipe especially when the pressurized liquid chamber forming member and the nozzle or diaphragm are joined. Therefore, it is possible to prevent the assembly failure due to the inflow of the adhesive and the injection bending due to the inflow of the adhesive.
[0015]
【Example】
FIG. 1 is an exploded perspective view showing a configuration of a droplet discharge head according to an embodiment of the present invention. In the figure, a droplet discharge head 100 of this embodiment includes a nozzle plate 101, a pressurized liquid chamber forming member 102, a vibration plate 103, and an actuator forming member 104. The nozzle plate 101 is formed with a large number of nozzle holes 105, which are fine holes for flying ink droplets, corresponding to the tip portions of the pressurized liquid chambers 106. The diameter of the nozzle holes 105 is 20 to 35 μm. It is. The nozzle plate 101 uses, for example, a Ni metal plate manufactured by an electroforming method, but silicon, other metal materials, or a resin film such as polyimide can be used. Note that a water-repellent surface treatment film is formed on the nozzle plate 101. The pressurized liquid chamber forming member 102 is formed of silicon, and (110) is used as the surface orientation of the silicon substrate. Thus, by using the (110) substrate, the pressurized liquid chamber 106 can be formed perpendicularly to the pitch direction of the nozzles, which is advantageous for miniaturization and narrow pitch. The pressurizing liquid chamber forming member 102 is formed with a communication pipe 107 and a pressurizing liquid chamber 106 communicating with each nozzle hole 105. The communication pipe 107 communicating with each nozzle hole 105 is formed by, for example, a dry etching method and an anisotropic etching method. The pressurized liquid chamber 106 and the common liquid chamber 108 are formed by an anisotropic etching method of Si. Further, an oxide film is formed on the surface of the silicon pressurized liquid chamber forming member 102. The formation of the oxide film makes it difficult for the ink to elute from the ink and improves the wettability, thereby preventing the bubbles from staying. This is not limited to an oxide film, but may be a titanium nitride (TiN) film or a polyimide film. The vibration plate 103 is made of a metal plate formed by a Ni electroforming method. The vibration function portion of the vibration plate 103 is joined to a beam portion 109 that is joined to a non-drive portion in the piezoelectric element and a drive portion in the piezoelectric element. It consists of island-shaped convex portions 110 and a thinnest film portion 111 (diaphragm region) having a thickness of about 2 to 10 μm formed around the convex portions 110. Further, the actuator forming member 104 joins a plurality of stacked piezoelectric elements, which are electromechanical conversion elements, arranged in rows on a ceramic substrate, for example, an insulating substrate such as barium titanate, alumina, and forsterite. These two rows of piezoelectric elements are cut by dicing. Note that the plurality of piezoelectric elements in each column alternately configure a drive unit 112 that applies a drive waveform in the channel direction and a non-drive unit 113 that does not apply a drive waveform. Here, the piezoelectric element is formed by alternately laminating internal electrodes made of zirconate titanate (PZT) having a thickness of 10 to 50 μm / layer and silver palladium (AgPd) having a thickness of several μm / layer. Low voltage driving is enabled by using a piezoelectric element having a thickness of 10 to 50 μm / layer. The electromechanical conversion element is not limited to PZT. Then, the internal electrodes of the piezoelectric element are alternately taken out to the end face, and the common electrode pattern and the individual electrode pattern are electrically connected to the end face electrode of the piezoelectric element serving as the driving unit on the substrate through a conductive adhesive or the like. Are connected to the PCB substrate via the common electrode pattern and the FPC cable connected to the common electrode pattern, and a drive waveform is applied to the drive unit to generate a displacement in the stacking direction.
[0016]
FIG. 2 is a cross-sectional view showing the structure of the pressurized liquid chamber forming member of the droplet discharge head in this embodiment. FIG. 2A is a cross-sectional view showing the structure of a single-sided channel method, and FIG. 2B is a cross-sectional view showing the structure of a double-sided channel method. In the figure, the same reference numerals as those in FIG. 1 denote the same components. In the structure of single-sided channel system shown in FIG. 2 (a), pressurized liquid chamber forming member 102 includes a pressurized liquid chamber 106, consisting of the communicating pipe 107 for communicating the pressurized liquid chamber 106 and the nozzle. Further, in the double-sided flow path structure shown in FIG. 2B, two flow paths where ink flows to the nozzles are formed at the nozzle surface side 201 and the diaphragm side 202 , even when driven at a high frequency. It has a structure that can sufficiently secure ink refill. The ink is pressurized by deforming the vibration plate with a piezoelectric element in the pressurized liquid chamber 106 , and then passes through the communication pipe 107 toward the nozzle. The pressurized ink is ejected from the nozzle.
[0017]
Here, comparing this embodiment with the conventional example, FIGS. 3A and 3B show the top view of the pressurized liquid chamber forming member and the nozzle of the pressurized liquid chamber forming member in the conventional example. It is a top view which shows a joining surface and a diaphragm joining surface. As shown to (a) of the figure, the shape of the communicating pipe opening part in a nozzle joint surface is a substantially parallelogram, and the two corners which consist of the acute angle of the part enclosed by the continuous line (circle) in the figure, It is surrounded by two corners consisting of an obtuse angle of the part surrounded by a dotted line ○ in the figure. In this way, bubbles are likely to stagnate and the ink flow is likely to stagnate at the acute corners surrounded by the solid line ○ in FIG. Further, as shown in (b) of the figure, the shape immediately below the communication pipe of the diaphragm joint portion is formed by three sides including one corner portion formed by an acute angle of a portion surrounded by a solid line ○ in the drawing. Yes. In the case of this shape, the adhesive flows into the communication pipe at the acute angle portion due to the capillary effect when the nozzle or the diaphragm is joined with the adhesive, which causes injection failure or injection bending. .
[0018]
On the other hand, FIGS. 4A and 4B are a top view of the pressurized liquid chamber forming member according to the present embodiment, and a top view of the nozzle bonding surface and the diaphragm bonding surface of the pressurized liquid chamber forming member according to the present embodiment. It is. As shown in the same figure (a), nozzle connection surface of this embodiment is formed by six sides which meet at an obtuse angle of six parts surrounded by a solid line ○ in FIG. Moreover, as shown in (b) of the figure, the diaphragm joint surface is formed by four sides that are in contact with each other at an obtuse angle surrounded by a solid line ◯ in the figure. For this reason, the adhesive does not flow into the inside of the communication pipe at the acute angle due to the capillary effect that has occurred in the conventional example, and it has a shape that does not cause problems such as injection failure and injection bending.
[0019]
Next, FIG. 5A is a perspective view of 1 bit of the pressurized liquid chamber forming member in the conventional example, and FIG. 5B is a perspective view of 1 bit of the pressurized liquid chamber forming member in the present embodiment. FIG. According to the conventional example shown in FIG. 5A, bubbles are likely to stagnate and ink flow is likely to stagnate at two acute corners surrounded by a solid line ◯ in the figure. On the other hand, according to the present embodiment shown in FIG. 5B, four surfaces (A, B, C, D) in which the surface joined to the nozzle directly below the communication pipe is perpendicular to the surface joined to the nozzle. And the surface to be joined to the nozzle and the two walls (E, F) that are in contact with each other at an obtuse angle, and the surface to be joined to the diaphragm directly below the communication pipe is perpendicular to the face to be joined to the diaphragm. Since the three walls (A, C, D) and the one wall (G) in contact with the surface to be joined to the nozzle at an obtuse angle are formed, there is no stagnation of bubbles and no stagnation of ink flow. Therefore, it has a shape capable of forming a highly reliable droplet discharge head that does not cause problems such as ejection down. Further, according to the present embodiment, as shown in FIG. 5B, the shape of the communication tube is surrounded by six sides surrounded by an obtuse angle on the nozzle surface, whereas in the communication tube, The shape is surrounded by four sides. By adopting such a shape, a higher order surface as shown in JP-A-7-178908, which is one of the conventional examples, is generated, and there is no problem that control is difficult. Since it consists of surfaces, it is possible to solve the problem that the surface is rattling and obstructs ink flow.
[0020]
FIG. 6 is a cross-sectional view illustrating a manufacturing process of a pressurized liquid chamber forming member of a droplet discharge head according to an embodiment of the present invention. First, as shown in FIG. 6A, a silicon substrate (110) 601 having a thickness of 400 μm is prepared, and a silicon oxide film 602 having a thickness of 1.0 μm and an LP-CVD nitride film 603 having a thickness of 0.2 μm are formed. To do. Next, as shown in FIG. 6B, the resist patterning 604 is performed in the shape of the hollow pattern 606 in which the connecting pipe forming pattern 605 and surplus adhesive at the time of joining flow into the nozzle joining surface, and then the nitride film 603 is patterned by dry etching. This communication pipe formation pattern has a shape formed by six sides that contact at an obtuse angle. Next, as shown in FIG. 6C, resist patterning 607 is performed, and then the silicon oxide film 602 is patterned by dry etching into the shape of the communication tube formation pattern 608. Thereafter, as shown in FIG. 6 (d), the resist is patterned in the shape of a pattern 610 of the pressurized liquid chamber and a pattern of hollowing pattern 609 into which surplus adhesive at the time of bonding with the diaphragm is poured, and then the nitride film The patterning 604 is performed by dry etching like the nozzle surface. Next, as shown in FIG. 6E, the silicon oxide film 602 is patterned in the shape of the communication tube formation pattern 612. Thereafter, as shown in FIG. 6F, the communication pipe shape 613 is patterned using an ICP dry etcher. At this time, the thickness of the resist 611 was 8 μm. Dry etching using an ICP etcher was performed to a depth of 300 μm. Thereafter, as shown in FIG. 6G, the resist 611 was removed, and silicon was anisotropically etched with a potassium hydroxide aqueous solution, and the communication pipe 614 was penetrated. In the step of penetrating the communication pipe 614 with an aqueous potassium hydroxide solution, etching is performed from both the nozzle surface side and the diaphragm side. Immediately after penetrating the communicating pipe, an inclined portion is generated by anisotropic etching. In this embodiment, the inclined portion is retracted in the communicating pipe penetrating step and all the inclined portions are etched. Thereafter, as shown in FIG. 6H, wet etching 615 of the silicon oxide film 602 is performed with dilute hydrofluoric acid using the nitride film 604 as a mask. Then, as shown in FIG. 6 (i), anisotropic etching of silicon is again performed with a potassium hydroxide aqueous solution to form a pressurized liquid chamber portion 616 and a lightening portion 617. Finally, as shown in FIG. 6J, the nitride film 604 and the silicon oxide film 602 are removed, and then a silicon oxide film having a thickness of 1 μm is formed as an ink-proof liquid contact film, and pressure applied for inkjet A liquid chamber forming member was formed.
[0021]
Thus, the junction surface of the nozzle formation member in the present embodiment is formed in a hexagonal contact at an obtuse angle, the junction surface of the vibration rotation plate is formed with Sessu that side at all obtuse. By not forming an acute angle portion on the joint surface between the nozzle forming member and the diaphragm, it is possible to prevent the adhesive from entering the communicating pipe due to the capillary effect when joining the nozzle forming member and the diaphragm in the subsequent process. Further, there is no stagnation of air bubbles by the high-order surface of the communicating pipe interior and the liquid room is not formed, the ink flows also became possible to form a highly reliable liquid jet head to be done smoothly .
[0022]
FIG. 7 is a sectional view showing another manufacturing process of the pressurized liquid chamber forming member according to the present invention. First, as shown in FIG. 7A, a silicon substrate (110) 701 having a thickness of 400 μm is prepared, and a silicon oxide film 702 having a thickness of 1.0 μm and an LP-CVD nitride film 703 having a thickness of 0.2 μm are formed. did. Next, as shown in FIG. 7B, resist patterning 704 is performed in the shape of a lightening pattern 706 that allows the nozzle surface-side flow path pattern 705 and excess adhesive at the time of bonding to flow into the nozzle bonding surface. The nitride film 703 is patterned by dry etching. The shape immediately below the communication pipe of the nozzle surface side flow path pattern is a shape formed by four sides that contact at an obtuse angle. Next, as shown in FIG. 7C, resist patterning 707 is performed, and the silicon oxide film 702 is patterned into the shape of the communication tube pattern 708 by dry etching. After that, as shown in FIG. 7D, the resist patterning and the nitride film 703 patterning are performed in the shape of a pattern 710 in the pressurized liquid chamber and a pattern 709 in which surplus adhesive at the time of bonding to the diaphragm is allowed to flow. I do. Next, as shown in FIG. 7E, the silicon oxide film 702 is patterned into the shape of the communication tube formation pattern 712. Thereafter, as shown in FIG. 7F, the communication pipe shape 713 is patterned using an ICP dry etcher. At this time, the film thickness of the resist 711 was 8 μm. Next, as shown in FIG. 7G, the resist 711 was removed, and silicon was anisotropically etched with a potassium hydroxide aqueous solution, and the communication pipe 714 was penetrated. Thereafter, as shown in FIG. 7H, wet etching 715 of the silicon oxide film 702 is performed with dilute hydrofluoric acid using the nitride film 703 as a mask. Then, as shown in FIG. 7I, anisotropic etching of silicon was again performed with a potassium hydroxide aqueous solution to form a pressurized liquid chamber portion 716, a nozzle surface channel portion 717, and a lightening portion 718. Finally, as shown in FIG. 7 (j), the nitride film 703 and the silicon oxide film 702 are removed, and then the silicon oxide film 702 is formed as an ink-proof liquid contact film with a thickness of 1 μm. A chamber forming member was formed.
[0023]
Thus, the bonding surface is formed by Sessu that side at all obtuse between the bonding surface and the diaphragm of the nozzle formation member in the present embodiment. By not forming an acute angle portion on the joint surface between the nozzle forming member and the diaphragm, it is possible to prevent the adhesive from entering the communicating pipe due to the capillary effect when joining the nozzle forming member and the diaphragm in the subsequent process. Also it becomes possible to form the inkjet reliable for stagnation of bubble by the high-order surface of the communicating pipe interior and the liquid room is not formed is also performed smoothly without ink flow. Further, in this embodiment, a flow path for supplying ink to the nozzles is also formed on the nozzle surface side, so that sufficient ink refilling during high frequency driving can be secured, and high-speed printing is possible.
[0024]
Next, an ink jet recording apparatus having the droplet discharge head of each of the above embodiments will be described.
FIG. 8 is a schematic sectional view showing the configuration of an ink jet recording apparatus according to another invention. As shown in the drawing, the ink jet recording apparatus 801 includes four ink cartridges 802 each containing ink of each color of cyan C, magenta M, yellow Y, and black BK, and a plurality of nozzles. Recording paper is supplied from four droplet discharge heads 803 to which ink is supplied, a carriage 804 on which ink cartridges 802 and droplet discharge heads 803 are mounted, paper feed trays 805a and 805b containing recording paper, and a manual feed table 806. A conveyance roller 808 that conveys the printing unit 807 and a discharge roller 810 that discharges the printed recording paper to a discharge tray 809 are provided. When printing image data sent from the host device on recording paper, droplets are ejected onto the recording paper sent to the printing unit 807 by the transport roller 808 while scanning the carriage 804 along the carriage roller 811. Characters and images are recorded by ejecting ink from the nozzles of the head 803 in accordance with image data. The liquid droplet ejection head 803 applied to the ink jet recording apparatus of the present invention is the liquid droplet ejection head of each of the above-described embodiments, and a vibration disposed so as to face the electrode by applying a voltage to the electrode. An attractive force acts between the plate and the electrostatic force, the diaphragm is deformed by the electrostatic force, and ink droplets are ejected from the nozzles.
[0025]
In addition, this invention is not limited to the said Example, It cannot be overemphasized that various deformation | transformation and substitution are possible if it is description in a claim.
[0026]
【The invention's effect】
As described above, the droplet ejection apparatus of the present invention includes a nozzle member having a nozzle which droplets are ejected, and the communicating pipe is joined to the nozzle forming member, a nozzle communicating with via the communication pipe And a diaphragm for pressurizing the pressurizing liquid chamber. Furthermore, according to the liquid droplet ejection apparatus of the present invention, the communicating pipe and pressurized liquid chamber is formed by anisotropic etching of the silicon single crystal substrate of plane orientation (110), the communicating pipe is a nozzle formed a contact Keru planar shape all edges at the interface between the member a hexagonal contact at an obtuse angle, is parallelogram cross-sectional shape in the extending direction central portion of the joint surface and parallel communication pipe. Therefore, when the nozzle forming member and the pressurized liquid chamber are joined with an adhesive, it is possible to prevent the adhesive from flowing into the communication pipe due to the capillary effect, and therefore, the droplet jetting bend due to the inflow of the adhesive. In addition, since it has a shape in which there is no stagnation of bubbles and there is no stagnation in the flow of ink, it is possible to provide a highly reliable droplet discharge head that is free from jetting down due to bubble retention.
[0027]
In addition, an ink jet recording apparatus as another invention is characterized in that the above-described droplet discharge head is mounted. Therefore, it is possible to provide a highly reliable inkjet recording apparatus using a droplet discharge head that can prevent the adhesive from flowing into the communication pipe and can prevent the stagnation of bubbles. it can.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a droplet discharge head according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a structure of a pressurized liquid chamber forming member of a droplet discharge head in the present embodiment.
FIG. 3 is a top view showing a pressurized liquid chamber forming member and a nozzle bonding surface and a diaphragm bonding surface of the pressurized liquid chamber forming member in a conventional example.
FIG. 4 is a top view of the pressurized liquid chamber forming member according to the present embodiment and the nozzle bonding surface and the diaphragm bonding surface of the pressurized liquid chamber forming member according to the present embodiment.
FIG. 5 is a perspective view of one bit of a pressurized liquid chamber forming member in a conventional example and in the present embodiment.
FIG. 6 is a cross-sectional view showing a manufacturing process of a pressurized liquid chamber forming member of a droplet discharge head according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view showing another manufacturing process of the pressurized liquid chamber forming member of the droplet discharge head according to the present invention.
FIG. 8 is a schematic cross-sectional view showing a configuration of an ink jet recording apparatus according to another invention.
[Explanation of symbols]
100; droplet discharge head; 101; nozzle plate; 102; pressurized liquid chamber forming member;
103; Diaphragm 104; Actuator forming member 105; Nozzle hole
106; pressurized liquid chamber, 107; communication pipe, 108; common liquid chamber,
109; beam part, 110; convex part, 111; thinnest film part, 112; drive part,
113: Non-driving part.

Claims (2)

A nozzle forming member having a nozzle from which droplets are discharged, a communication pipe joined to the nozzle forming member, a pressurized liquid chamber communicating with the nozzle through the communication pipe , and pressurizing the pressurized liquid chamber With a diaphragm,
Before Kirendorikan and the pressurized liquid chamber is formed by anisotropic etching of the silicon single crystal substrate of plane orientation (110),
Said communicating pipe, said contact Keru planar shape at the interface between the nozzle forming member has a hexagonal all sides meet at an obtuse angle, the cross-sectional shape in the extending direction central portion of the front Symbol communicating tube parallel to the junction surface Is a parallelogram . An ink jet recording apparatus comprising the droplet discharge head according to claim 1 .

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