JP4103256B2 - Inkjet head manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic drive ink jet head, and more particularly to an electrostatic drive ink jet head having a structure suitable for miniaturization and high density.
[0002]
[Prior art]
For example, as disclosed in Japanese Examined Patent Publication No. 2-289351, an electrostatically driven inkjet head includes a diaphragm that forms part of an ink flow path that communicates with ink nozzles, By applying a voltage between the electrodes facing each other with a predetermined gap and changing the volume in the flow path, ink droplets are ejected from the ink nozzles. A conventional inkjet head of this type is generally configured by laminating three substrates.
[0003]
That is, as shown in FIGS. 6 and 7, the inkjet head 100 includes an electrode plate 101 made of a glass substrate, a cavity plate 102 made of a silicon substrate, and a nozzle plate 103 made of a silicon substrate, which are laminated by anodic bonding or the like. It has a layer structure. By performing anisotropic etching from the surface side of the cavity plate 102, a groove 104 for an ink pressure chamber, a groove 105 for a common ink chamber, and a groove 106 for an orifice for communicating these are formed. In addition, by controlling the depth of the groove 104 for the ink supply chamber, the groove bottom plate portion is a vibration plate 107 that can be elastically displaced in the out-of-plane direction.
[0004]
Ink nozzles 108 are formed on the nozzle plate 101 stacked on the surface side of the cavity plate 102. By joining the nozzle plate 101 to the cavity plate 102, an ink pressure chamber 109 communicating with the ink nozzle 108, a common ink chamber 110, and an orifice 111 communicating these are partitioned.
[0005]
On the other hand, the electrode plate 101 bonded to the back surface side of the cavity plate 102 is subjected to isotropic etching from the front surface to form a groove 112 at a portion facing each diaphragm 107, and this groove Individual electrodes 113 are formed on the bottom surface. By joining the electrode plate 101 to the back surface of the cavity plate 102 and attaching the sealing material 114, a sealed gap 114 is formed between each individual electrode 113 and the corresponding diaphragm 107. Yes.
[0006]
By applying a voltage between the diaphragm 107 and the corresponding individual electrode 113 and generating an electrostatic force therebetween, the volume of the ink pressure chamber 109 changes, and the ink droplets are discharged from the ink nozzles 108. Discharge.
[0007]
[Problems to be solved by the invention]
In order to achieve miniaturization and high density in the ink jet head having this configuration, it is necessary to increase the density of its constituent parts. However, when the size and density are increased, the partition walls between adjacent ink pressure chambers formed by etching the cavity plate are also reduced.
[0008]
In particular, a groove for forming an ink pressure chamber is formed by anisotropic etching, and a diaphragm having desired characteristics is formed by the groove depth. Therefore, when the density is increased, the partition wall becomes thicker. It becomes difficult to form a groove having a predetermined depth.
[0009]
As a result, the rigidity of the partition wall is lowered, so that pressure interference (crosstalk) occurs between the adjacent ink pressure chambers, and there is a possibility that an appropriate ink droplet ejection operation is hindered.
[0010]
Conventionally, since the ink jet head is configured by joining three plates to each other, it is necessary to perform alignment of these with high accuracy, so that assembly accuracy is also required. Furthermore, it is necessary to accurately etch the grooves for forming the ink flow path on each plate, and it may be difficult to obtain an accurate ink jet head when increasing the density.
[0011]
In view of the above, an object of the present invention is to propose an ink jet head having a structure that can easily achieve miniaturization and high density.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes an ink pressure chamber, an ink nozzle communicating with the ink pressure chamber, and a diaphragm as a common electrode forming a part of the ink pressure chamber. An electrostatic drive type ink jet head having an individual electrode facing the diaphragm via a gap is characterized by adopting the following configuration.
[0013]
That is, the ink jet head of the present invention has first and second substrates. Further, the individual electrode and the diaphragm facing the individual electrode through the gap formed by sacrificial layer etching are formed on the surface of the first substrate. Further, an ink pressure chamber groove for forming the ink pressure chamber is formed on the surface of the second substrate. In addition, by joining the first and second substrates, the groove portion for the ink pressure chamber formed on the surface of the second substrate is closed by the first substrate. An ink chamber is formed.
[0014]
In the ink jet head of the present invention, a groove for forming an ink flow path portion (ink nozzle, ink pressure chamber) is formed in the first substrate, and the electrostatic actuator portion (vibrating plate) utilizes sacrificial layer etching. It is formed on a separate second substrate. Therefore, the diaphragm formation and the depth of the ink pressure chamber groove can be arbitrarily determined without considering the thickness of the diaphragm. Therefore, if the groove depth is reduced and the height of the partition between the ink pressure chambers is reduced, sufficient partition rigidity can be ensured even when the partition thickness is reduced.
[0015]
As a result, even if the inkjet head is downsized and densified, it is possible to prevent adverse effects such as pressure interference between adjacent ink pressure chambers due to a decrease in partition rigidity between ink pressure chambers and deterioration of ink ejection characteristics. Is done. Further, in the present invention, since the ink jet head can be manufactured by joining the two parts of the first and second substrates, it is easier to manufacture than the case of manufacturing the ink jet head by stacking three substrates. In addition, assembly errors during assembly can be reduced.
[0016]
The first and second substrates are preferably joined via a diaphragm formed on the surface of the first substrate.
[0017]
With the above configuration, there is no need to remove the bonding portion of the diaphragm formed on the surface of the first substrate with the second substrate, and a process for partially etching the diaphragm is unnecessary. Its manufacture is facilitated.
[0018]
Furthermore, nozzle holes or nozzle grooves for forming the ink nozzles may be formed on the surface of the second substrate.
[0019]
In this case, since the nozzle hole or nozzle groove and the groove portion for the ink pressure chamber are integrally formed in the second substrate, the positional deviation between the ink pressure chamber and the nozzle hole or nozzle groove is reduced, and the ink droplet is discharged. The ink flow in the ink flow path is not disturbed. Since there is no disturbance in the ink flow in the ink flow path, the flying direction and amount of the ejected ink droplets are constant, and the print quality can be further improved.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
An example of an inkjet head to which the present invention is applied will be described below with reference to the drawings.
[0021]
FIG. 1 is a schematic perspective view showing the electrostatically driven ink jet head of this example partially cut away, FIG. 2 is a schematic cross-sectional view of the portion cut along the line II-II, and FIG. It is a fragmentary sectional view of the part cut | disconnected by the III-III line.
[0022]
First, referring to FIG. 1, an ink jet head 1 of this example includes a flow path substrate 2 (first substrate) made of a semiconductor substrate such as silicon, and a glass actuator substrate 3 (second substrate). Are anodic bonded or adhesively bonded. Ink nozzles 4 are opened on the front surface 1a of the inkjet head 1 at regular intervals, and ink intake ports 5 and 6 for taking in ink supplied from outside are opened on the upper surface portion on the rear side. Between these, the terminal portions 7 of the individual electrodes made of ITO or the like are exposed in a number corresponding to the number of the ink nozzles 4, and the common electrode terminal portions 8 are formed at the side positions thereof. .
[0023]
The internal structure will be described with reference to FIGS. Each ink nozzle 4 of the inkjet head 1 communicates with an ink pressure chamber 9, and each ink pressure chamber 9 is partitioned from each other by a partition wall 10. Each ink pressure chamber 9 communicates with a common ink chamber 12 via an orifice 11. Ink is supplied to the common ink chamber 12 from the outside through the ink intakes 5 and 6. A vibration plate 13 is formed on the bottom surface of each ink pressure chamber 9, and this vibration plate 13 faces the individual electrode 15 via a sealed gap portion 14.
[0024]
A part of the common ink chamber 12 is defined by a diaphragm 16 that can be elastically displaced in the out-of-plane direction. The diaphragm 16 is for suppressing or absorbing ink pressure fluctuation in the ink flow path caused by the ink discharge operation.
[0025]
The diaphragm 13 is electrically connected to the common electrode terminal portion 8, and each individual electrode 15 is led out to the outside as an individual electrode terminal portion 7. When a voltage is applied between the diaphragm 13 and each individual electrode 15, an electrostatic force is generated between them, and thereby the diaphragm 13 is elastically displaced in the out-of-plane direction, in the vertical direction in FIGS. As a result, the volume of the ink pressure chamber 9 fluctuates, and ink droplets are ejected from the ink nozzle 4 communicating with the ink pressure chamber 9. Since such an ink ejection principle is known, further description is omitted in this specification.
[0026]
Here, each part in the inkjet head 1 of the present example is configured as follows. First, the flow path substrate 2 has a nozzle groove 4a for forming an ink nozzle and an ink pressure chamber forming surface formed on the surface bonded to the actuator substrate 3 by anisotropic etching such as dry etching or wet etching. A groove 9a, an orifice forming groove 11a, and a common ink chamber forming groove 12a are formed. Further, a concave portion 16a for forming a diaphragm is formed on the opposite surface of the flow path substrate 2 by dry etching or wet etching.
[0027]
In this case, the side walls of the ink pressure chamber forming groove 9a formed in the flow path substrate 2 and the orifice forming groove 11a are formed perpendicularly or at a constant angle on the (111) plane of the single crystal silicon, High-precision grooves 9a and grooves 11a can be formed with high density. (110) By wet etching the wafer, a side wall perpendicular to the actuator substrate can be formed. When (100) wafer is wet etched, a side wall having an inclination of 54.7 degrees is formed with respect to the actuator substrate. can do.
[0028]
Therefore, in the case of an ink jet head having a higher response by reducing the resistance of the flow path, it is desirable to wet etch the (110) wafer to form the sidewalls vertically.
[0029]
When pressure interference between adjacent ink pressure chambers is prevented, it is desirable to increase the rigidity by wet etching (100) wafer.
[0030]
On the other hand, in the actuator substrate 3, each individual electrode 15 is formed on the surface 3a joined to the flow path substrate 2 side. A vibration plate 13 is also formed on the surface 3 a, and a gap 14 sealed by the vibration plate 13 is formed in a portion of the vibration plate 13 that faces the individual electrode 15. This void 14 is formed by sacrificial layer etching. Therefore, the portion of the diaphragm 13 that faces the gap portion 14 functions as the vibrating portion 13A.
[0031]
The flow path substrate 2 and the actuator substrate 3 configured in this way are laminated to each other by anodic bonding or adhesive bonding. As a result, each ink nozzle 4, each ink pressure chamber 9, Each orifice 11 and a common ink chamber 12 are partitioned.
[0032]
When the actuator substrate 3 and the flow path substrate 2 are joined, the vibration plate 13 in the portion of the surface 3a to be joined can be further removed by etching and processed, and then they can be joined without using the vibration plate 13. It is. For example, if the vibration plate 13 is removed from the surface 3a portion where the actuator substrate 3 and the flow path substrate 2 are bonded and anodic bonded, the bonding at the time of bonding these substrates can be stabilized and the strength can be improved. It becomes.
[0033]
(Method for forming vibrating portion 13A)
Here, the vibrating portion 13A of the diaphragm 13 formed on the surface 3a of the actuator substrate 3 of this example is formed by sacrificial layer etching.
[0034]
The sacrificial layer etching is performed by, for example, forming the sacrificial layer after forming the sacrificial layer as described on page 8 of JP-T-10-510374 and page 2 of US Pat. No. 5,4596. This is a method of forming voids by etching. The conventional void formed by sacrificial layer etching is an open void provided to modulate the position of the reflective surface of the light valve by electrostatic force. As in the inkjet head 1 of this example, a method using sacrificial layer etching to form a sealed void is not proposed.
[0035]
In this example, for example, the closed gap 14 is formed between the diaphragm 13 and the individual electrode 15 as follows. Referring to FIG. 3, first, an ITO electrode layer is formed on a glass substrate for forming the actuator substrate 3 by sputtering, for example, and this layer is patterned by photolithography to form each individual electrode 15. Form.
[0036]
Next, a sacrificial layer is formed by vapor-depositing aluminum to a predetermined thickness so as to cover each individual electrode 15 (a portion corresponding to the gap portion 14 in FIG. 3). An insulating layer 21 made of silicon dioxide is formed on the surface of the sacrificial layer. Thereafter, a diaphragm 13 made of polysilicon having a predetermined thickness is formed so as to cover the insulating layer 21 and the exposed glass substrate surface. Thereafter, the sacrificial layer is etched away with an etching solution such as a mixed solution of phosphoric acid, hydrochloric acid, and hydrogen peroxide using the etch holes opened in the diaphragm 13. As a result, the sacrificial layer forming portion becomes a gap, and the portion 13A of the diaphragm 13 laminated on the sacrificial layer via the insulating layer 21 becomes a vibrating portion that is lifted from the individual electrode 15 by a predetermined gap. Thereafter, the insulating layer 22 made of silicon dioxide is formed on the entire surface of the diaphragm 13. In addition, the portion of the diaphragm forming layer used as an etch hole is also sealed to form a closed gap 14.
[0037]
As a material for forming the diaphragm 13, platinum or nickel may be used in addition to the above-described polysilicon. By using these metals for the material of the diaphragm 13, the diaphragm 13 having higher conductivity can be obtained, which is convenient for increasing the density of the flow path.
[0038]
Further, silicon nitride may be used as the material of the insulating layer 21. When the actuator substrate 3 is formed using these materials, silicon dioxide is used as the sacrificial layer, and hydrofluoric acid is used as the etching solution. In this case, the silicon dioxide that is the mask of the flow path substrate 2 can be the same as the etching solution.
[0039]
(Example of ink jet recording apparatus)
FIG. 4 is a schematic configuration diagram showing the main components of the inkjet recording apparatus on which the inkjet head 1 having the above-described configuration is mounted. The ink jet recording apparatus 40 includes a carriage mechanism 42 that reciprocates the ink jet head 1 along a guide rail 41, and a transport mechanism that includes a feed roller 44 that transports a recording sheet 43 via a recording position of the ink jet head 1. 45. The ink jet head 1 is supplied with ink from an ink supply unit (not shown) via an ink tube.
[0040]
Next, FIG. 5 is a schematic configuration diagram showing main components of a line printer in which the inkjet head 1 having the above configuration is mounted as a line head. The line printer 50 of this example includes a line head 51 arranged so as to include a recording range, and a transport mechanism 55 including feed rollers 53 and 54 that transport the recording paper 52 via a recording position by the line head. And an ink supply mechanism 57 including an ink pipe 56 for supplying ink to the line head 51, and a control circuit portion (not shown).
[0041]
The present invention is not limited to the above-described embodiment, and various changes can be made.
[0042]
For example, in the above embodiment, the nozzle groove 4a for forming the ink nozzle is formed on the flow path substrate 2, but it may be formed on the actuator substrate 3. When formed in the flow path substrate 2, the nozzle groove 4 a and the ink pressure chamber forming groove 9 a can be integrally formed by a method such as anisotropic etching, and the mutual positions of the nozzle 4 and the ink pressure chamber 9. The displacement can be prevented, the flow in the ink flow path is not disturbed by the mutual displacement between the nozzle 4 and the ink pressure chamber 9, and the variation in the flying direction and the amount of ink droplets ejected from the nozzle 4 is reduced. Therefore, it is possible to obtain an effective effect such as being able to obtain an ink jet head of a recording apparatus having excellent print quality.
[0043]
【The invention's effect】
As described above, the ink jet head of the present invention is configured by bonding a first substrate and a second substrate, and grooves for ink flow paths are formed on the first substrate by anisotropic etching. The second substrate is formed with an individual electrode and a vibration plate having a vibration portion formed by sacrificial layer etching.
[0044]
Therefore, according to the present invention, since it is not necessary to form a diaphragm on the first substrate, the depth of the ink channel groove to be formed on the substrate can be arbitrarily set. Therefore, the grooves can be made shallower, and the partition walls partitioning the grooves for forming the ink pressure chambers can be lowered. As a result, even when the ink jet head is reduced in size and density, the partition wall rigidity between the ink pressure chambers can be made sufficient, and pressure interference between the ink pressure chambers can be prevented.
[0045]
In addition, since the ink jet head can be manufactured by joining the two parts of the first and second substrates, it is possible to easily manufacture an ink jet head with high accuracy with few assembling errors.
[0046]
As described above, according to the present invention, it is possible to realize an ink jet head that can easily achieve miniaturization and high density.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a state in which an electrostatic drive type inkjet head to which the present invention is applied is partially cut away.
2 is a schematic cross-sectional view taken along line II-II in FIG.
3 is a schematic partial cross-sectional view taken along line III-III in FIG.
FIG. 4 is a schematic configuration diagram showing an example of an ink jet printer equipped with an ink jet head according to the present invention.
FIG. 5 is a schematic configuration diagram showing an example of a line printer equipped with a line head according to the present invention.
FIG. 6 is a schematic configuration diagram showing a cross-sectional configuration of a conventional electrostatically driven inkjet head.
7 is a schematic configuration diagram illustrating a planar configuration of the inkjet head of FIG. 6;
[Explanation of symbols]
1 Inkjet printer 2 Flow path substrate (first substrate)
3 Actuator board (second board)
4 Ink nozzle 4a Nozzle groove 5, 6 Ink intake port 7 Individual electrode terminal portion 8 Common electrode terminal portion 9 Ink pressure chamber 9a Groove 11 for forming ink pressure chamber Orifice 11a Groove 12 for forming orifice Common ink chamber 12a Common ink chamber Forming groove 13 Diaphragm 13A Oscillating portion 14 of diaphragm Oscillating portion 15 formed by sacrificial layer etching Individual electrode

Claims (1)

An ink pressure chamber, an ink nozzle communicating with the ink pressure chamber, a diaphragm serving as a common electrode forming a part of the ink pressure chamber, and the diaphragm opposed to the diaphragm via a gap. In the manufacturing method of the electrostatic drive type ink-jet head having the individual electrodes,
Having first and second substrates;
The second substrate is glass,
A nozzle forming step of forming the ink nozzles on the first substrate;
The surface of said first substrate, and the ink pressure chamber forming step of forming a groove for the ink pressure chamber for forming the ink pressure chamber,
An electrode forming step of forming the individual electrodes on the surface of the second substrate;
A sacrificial layer forming step of forming a sacrificial layer on the surface of the individual electrode;
A diaphragm forming step of forming the diaphragm on the surface of the sacrificial layer;
Forming an etch hole in the diaphragm, and forming a void by etching the sacrificial layer using the etch hole ; and
A sealing step of forming an insulating layer on the surface of the diaphragm to seal the etch hole;
Said first and second substrate and a substrate bonding step you joined through the diaphragm,
An ink jet head manufacturing method, wherein the ink pressure chamber is formed by closing a groove for the ink pressure chamber formed on the surface of the first substrate by the second substrate.

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