JP2002240275A - Liquid drop ejection head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that durability can not be ensured with high reliability over a long term. SOLUTION: A heavily doped diffusion layer 23 forming a movable plate 10 has a part where the distribution in the depth direction becomes uneven or discontinuous at least partially in the plane of a silicon substrate 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head and an ink jet recording apparatus.

[0002]

2. Description of the Related Art An ink jet head, which is a droplet discharge head used in an image recording apparatus such as a printer, a facsimile, a copying apparatus, a plotter or the like, or an ink jet recording apparatus used as an image forming apparatus, comprises a nozzle for discharging ink droplets, Pressurized liquid chamber with which the nozzle communicates (also referred to as liquid chamber, discharge chamber, pressure chamber, ink flow path, etc.)
And a pressure generating means for generating a pressure for pressurizing the ink in the pressurized liquid chamber, and the ink in the pressurized liquid chamber is pressurized by the pressure generated by the pressure generating means, thereby ejecting ink droplets from the nozzles.

[0003] Such an ink jet head is of a piezo type in which an ink droplet is ejected by deforming and displacing a movable plate forming a wall surface of a pressurized liquid chamber using an electromechanical transducer such as a piezoelectric element. A bubble type in which a bubble is generated by ink film boiling using a heating resistor disposed in a pressurized liquid chamber to discharge ink droplets, and a movable plate forming a wall surface of the pressurized liquid chamber (or There is an electrostatic type that discharges ink droplets by deforming and displacing a movable plate with electrostatic force using an electrode (integrated electrode) and an electrode.

When the deformation displacement of the movable plate is used as the pressure generating means, such as the piezo type or the electrostatic type described above, a silicon material which is excellent in mechanical strength, a micro-machining process is established, and excellent in cost performance is used. Often used as a material for forming a pressurized liquid chamber or a movable plate.

As a simple forming process for producing a movable plate made of a silicon material, for example, Japanese Patent Application Laid-Open No. Sho 53-6388
No. 0 or JP-A-6-71882, a high-concentration p-type impurity diffusion layer in which a high-concentration p-type impurity (dopant) serving as a movable plate portion is diffused is formed on a silicon substrate. There is known a method in which a diffusion layer is left by anisotropic selective etching using an alkaline etching solution such as an aqueous solution of potassium hydroxide to form a movable plate formed of the diffusion layer and a concave portion serving as a pressurized liquid chamber. The method of forming a movable plate using this high-concentration p-type impurity diffusion layer has excellent plate thickness controllability.

[0006]

However, when a movable plate is formed from a high-concentration p-type impurity diffusion layer formed on a silicon substrate, the difference in the atomic radius or the dopant concentration between the dopant and silicon atoms during p-type dopant diffusion. In the diffusion layer, dislocations occur due to lattice mismatch. Also, in the above-described method using selective etching, the etching rate in the diffusion layer varies depending not only on the dopant concentration but also on the density (+ type) of crystal defects. The thickness of the movable plate is reduced by the occurrence of dislocation. In addition, since the dislocation acts to release the stress, the internal stress of the movable plate also decreases.

Particularly, in an electrostatic ink jet head, since the displacement return force of the movable plate is used, the flexural rigidity of the movable plate greatly affects the driving characteristics of the head and affects the ink droplet ejection characteristics. In particular, with the increase in density and integration of the head, the thickness of the movable plate is in the direction of thinning, so that the thickness of the movable plate, which is a control element for flexural rigidity, and the variation in the occurrence of dislocations in the diffusion layer that changes the internal stress Control is required.

The present invention has been made in view of the above problems, and has as its object to provide a droplet discharge head having high durability and reliability and an ink jet recording apparatus equipped with the same.

[0009]

In order to solve the above-mentioned problems, a droplet discharge head according to the present invention comprises a movable plate formed of a high-concentration p-type impurity diffusion layer formed on a silicon substrate. In the above, the high-concentration impurity diffusion layer forming the movable plate has a configuration in which the distribution in the depth direction is non-uniform or discontinuous at least partially in the plane of the silicon substrate.

Here, a recess may be provided in a part of the surface of the diffusion surface of the silicon substrate to form the high concentration p-type impurity diffusion layer serving as a movable plate. Further, a non-diffusion portion or a portion having a diffusion portion having a different concentration distribution can be provided on the surface of the silicon substrate on which the high concentration p-type impurity diffusion layer is formed.
Further, the p-type impurity is preferably a substance having a smaller atom covalent bond radius than a silicon atom.

Further, it is preferable that an electrode facing the movable plate is provided, and the movable plate is displaced and deformed by electrostatic force to discharge droplets. In this case, a plurality of pressurized liquid chambers are formed in the silicon substrate, and a non-uniform or discontinuous portion of the high-concentration p-type impurity diffusion layer connects individual gaps formed between the movable plate and the counter electrode. It is preferable that the connection chamber also serves as a connection chamber. Also, a plurality of pressurized liquid chambers are formed in the silicon substrate,
Non-uniform or discontinuous portions of the high concentration p-type impurity diffusion layer
It is preferable to provide a supply path for supplying a liquid to the pressurized liquid chamber. Alternatively, it is preferable that a non-uniform portion of the high-concentration p-type impurity diffusion layer forms a gap between the movable plate and the counter electrode.

[0012] The ink jet recording apparatus according to the present invention comprises:
A droplet discharge head according to the present invention is mounted as an inkjet head that discharges ink droplets.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an electrostatic ink jet head (droplet discharge head) according to the present invention, FIG. 2 is a top view of the same head excluding a nozzle plate, and FIG.
Is a schematic sectional explanatory view along the movable plate longitudinal direction of the head,
FIG. 4 is a schematic cross-sectional explanatory view of the head along the shorter direction of the movable plate.

The droplet discharge head includes a flow path substrate 1 as a first substrate, an electrode substrate 3 as a second substrate provided below the flow path substrate 1, and a first substrate provided above the flow path substrate. This is a laminated structure in which a nozzle plate 3 as three substrates is overlapped and joined, and a plurality of nozzles 5, a pressurized liquid chamber 6 which is an ink flow path communicating with each nozzle 5, and a fluid are supplied to the pressurized liquid chamber 6. A common liquid chamber 8 that communicates via the resistance portion 7 is formed.

The flow path substrate 1 includes a plurality of pressurized liquid chambers 6 and a movable plate 1 forming a bottom wall of the pressurized liquid chamber 6.
0, and a concave portion serving as a common liquid chamber 8 for supplying ink to the individual pressurized liquid chambers 6 is formed. This flow path substrate 1
Is to diffuse boron, which is a p-type dopant (impurity), into a silicon substrate having a (110) plane orientation so that the distribution in the depth direction is partially non-uniform or discontinuous in a part of the silicon substrate. A diffusion layer 2 is formed, and the high-concentration boron diffusion layer 2 is used as an etching stop layer to perform anisotropic selective etching, thereby forming a diaphragm 10 including the high-concentration boron diffusion layer 2.
And a concave portion serving as the pressurized liquid chamber 6 is formed.

For example, when an aqueous solution of 20 wt% potassium hydroxide to which isopropyl alcohol is added in a saturated amount or more is used as an etching solution, the etching rate decreases to 1/100 or less at a boron diffusion concentration of about 4 to 5E19 cm ^-3. Therefore, the movable plate 10 can be formed with a relatively uniform thickness. However, the etching selectivity differs depending on the defect density and the like, and also depends on the impurity introduction method / condition.

In this embodiment, the movable plate 10 is a first plate.
Although the electrode also serves as an electrode, an electrode film may be separately formed on the movable plate 10. Although not shown, a silicon oxide film is formed on the surface of the movable plate 10 on the electrode substrate 3 side by thermal oxidation to prevent short circuit.

A thermal oxide film 3a is formed on the electrode substrate 3 by a thermal oxidation method using a silicon substrate. An electrode forming groove (recess) 14 is formed in the thermal oxide film 3a. A second opposed to the plate 10 via a predetermined gap 16;
An electrode 15, which is an electrode, is formed. This electrode 15
An actuator unit extending to near the end of the electrode substrate 3 and displacing the movable plate 10 by applying a voltage between the electrode 15 and the movable plate 10 to change the internal volume of the pressurized liquid chamber 6 Is composed. Further, an ink supply port 18 for connecting an external ink tank (not shown) to the common liquid chamber 8 of the flow path substrate 1 is also formed.

In the electrode substrate 3 of this embodiment, a concave portion 14 is formed at a desired depth by etching with a hydrogen fluoride aqueous solution on a silicon substrate on which a base thermal oxide film 3a is formed.
An electrode material is formed on the concave portion 14 to a desired thickness by a thin film forming method such as sputtering, CVD, or vapor deposition, and then a photoresist is formed on the electrode pattern and etched to form the electrode 15 on the bottom surface of the concave portion 14. Has formed. Further, a protective film 17 made of a silicon oxide film is formed on the electrode 15 to prevent the electrode 15 from being damaged due to a short circuit or the like.

The electrode substrate 3 and the flow path substrate 1 can be joined using low-melting-point glass and various adhesive members.
If a high heat-resistant material such as titanium nitride is used for the electrode material, a direct bonding method can be used. If a Pyrex (registered trademark) glass substrate is used for the electrode substrate, an anodic bonding method or the like can be used, even if an adhesive member is not required. it can. Also, usually
In order to isolate the gap 16 from atmospheric contamination and humidity, the opening of the gap 16 is sealed with a sealing material 19 or the like, and the inside of the gap 16 is sealed at atmospheric pressure or reduced pressure atmosphere.

The nozzle plate 4 is formed with a thin stainless steel material to form the nozzle 5 and the fluid resistance portion 7. In addition, as a base material of the nozzle plate 4, not only a stainless steel material but also a silicon material or a photosensitive resin material, which can be easily finely processed, can be used as a constituent member.

The silicon nitride films (or silicon oxide films) 12a, 12 used as etching masks are formed on the surface of the flow path substrate 1 on the side of the nozzle plate 4 and the outer surface of the electrode substrate 3.
b is allowed to remain.

In this ink-jet head, for example, 10 to 1 is provided between the movable plate 10 serving also as the first electrode and the electrode 15 serving as the second electrode, with the movable plate 10 serving as the ground.
By applying a pulse potential of about 00V, the movable plate 10
, A negative charge is induced on the surface of the movable plate 10 (the movable plate 10).
The movable plate 10 is moved by the electrostatic force between the
The ink is filled into the pressurized liquid chamber 6 by being deformed to the side 5. Subsequently, when the voltage application to the electrode 15 is turned off, the movable plate 10 is restored to the pressurized liquid chamber 6 side with the release of the charge accumulated between the electrodes. At that time, a sudden volume change /
A pressure change occurs, and the filled ink is ejected from the nozzle 5 as ink droplets.

The high concentration p-type impurity diffusion layer forming the movable plate 10 of the flow path substrate 1 in the ink jet head will be described with reference to FIG. Here, a recess is formed in a part of the boron diffusion surface for forming the movable plate 10 of the silicon substrate to be the flow path substrate 1. That is, a silicon substrate (silicon wafer) 20 for forming the flow path substrate 1 as shown in FIG.
Then, an etching mask such as a photoresist or a silicon nitride film or a silicon oxide film and a mask layer 21 are formed.

Thereafter, as shown in FIG. 2B, the recess 22 is formed by dry etching such as reactive ion etching or wet etching using a hydrogen fluoride-nitric acid type etching solution. Next, after the mask layer is removed as shown in FIG.
Boron is diffused over the entire surface on which the layer 2 is formed to form a high-concentration boron diffusion layer 23. In addition, as a boron diffusion method, a diffusion method such as a solid diffusion method, an ion implantation method, and a coating diffusion method can be selected according to a diffusion depth / concentration, a mask layer used for a pattern, and the like.

Next, another example of the high-concentration p-type impurity diffusion layer forming the movable plate 10 of the flow path substrate 1 will be described with reference to FIGS. Here, a non-diffusion portion is provided in a part of the silicon substrate serving as the flow path substrate 1 or the diffusion distribution is changed. That is, as shown in FIG. 1A, a buffer layer 24 such as a silicon nitride film or a silicon oxide film is formed on a portion of the silicon substrate 20 where the boron diffusion distribution is to be changed.

Thereafter, as shown in FIG. 2B, boron is diffused to form a high-concentration p-type diffusion layer 23, and the buffer layer 24 is removed as shown in FIG. The non-diffusion portion 25 is formed together with the mold diffusion layer 23.

Next, still another example of the high-concentration p-type impurity diffusion layer forming the movable plate 10 of the flow path substrate 1 will be described with reference to FIGS. Here, both the concave portion and the non-diffusion portion are formed on the boron diffusion surface of the silicon substrate serving as the flow channel substrate 1. That is, as shown in FIG. 1A, a nitride film (or a laminate of this and a nitride film on an oxide film) mask layer 21 is formed on a silicon substrate 20.

Thereafter, the opening of the mask layer 21 is thermally oxidized to form an oxide layer 26 on the silicon substrate 20 as shown in FIG. 3B, and an aqueous solution of hydrogen fluoride is formed as shown in FIG. By removing the oxide layer 26 to form the concave portion 22 and diffusing boron without removing the mask layer 21 as it is to form the high-concentration p-type diffusion layer 23, the mask layer 21 is removed. On the boron diffusion surface of the silicon substrate 20, both the concave portion 22 and the non-diffusion portion 25 are formed together with the high-concentration p-type diffusion layer.

After forming the concave portion 22 in the example of FIG.
By performing the diffusion without removing the mask layer 21 before the diffusion, a configuration similar to the example of FIG. 7 can be obtained.
After forming the recesses 22 in the example of FIG.
By removing and diffusing the entire surface, a configuration similar to the example of FIG. 5 can be obtained.

When dopants having different atomic covalent radii are introduced into the silicon crystal in this manner, the size of the crystal lattice changes, and internal stress is generated in the diffusion layer. In the case of a dopant having a smaller covalent atomic radius than silicon, such as boron, which is often used as a p-type dopant, the lattice constant becomes small and a tensile stress is generated. Silicon is plastically deformed at a high temperature such as during or after direct bonding, so that when lattice irregularity / stress is large, dislocations are generated so as to relieve the stress.

As a result, when the boron is uniformly diffused on the surface of the silicon substrate, the dislocation expands to different areas due to the thermal history because the boron concentration distribution is uniform in the surface. On the other hand, for example, as shown in FIG. 5, the areas a1, a2, a3
By forming a non-uniform or discontinuous portion therebetween, dislocation movement is prevented or fixed from other areas in the sandwiched portion, and the dislocation density is reduced.

To examine this effect, as shown in FIGS. 8 and 9 (FIG. 9 is an enlarged sectional view of a portion A in FIG. 8B), a silicon wafer 33 having a crystal plane orientation (110) of 6 inches
Forming a silicon nitride film / thermal oxide film mask layer 21 with a thickness of 0.1 μm / 0.05 μm by CVD, and a width of 15 μm so that a lattice equivalent to the chip size of the inkjet head can be formed on the boron diffusion surface side; Lattice pattern 30
Is formed by the method of FIG. 5 (recess depth d = 10 μm) and the method of FIG. 6, and a boron oxide layer serving as a diffusion source is formed by a vapor phase method at 0.7.
It was formed to a depth of μm and diffused under the conditions of 1125 ° C. for 40 min.

Subsequently, an etching pattern for forming a cavity 31 of the same size as the pressurized liquid chamber is formed on the opposite surface side so as to correspond to the inside of the lattice pattern 30 on the boron diffusion surface side, and 20 wt. %
The boron diffusion layer 23 was left with an aqueous solution of potassium hydroxide to prepare a movable plate 10 having a plate thickness of 2 μm and a short side width of 120 μm. Then, the displacement of the movable plate 10 is changed by reducing the pressure in the cavity 31 of the silicon substrate, and the rigidity variation of the movable plate 10 within the wafer / between wafers is evaluated based on the displacement amount of the movable plate 10, and a pattern is formed on the diffusion surface. It was compared with the case without forming.

As a result, the variation in displacement of the movable plate 10 is
5 and 6 in which the non-uniform / discontinuous diffusion layer pattern is formed is smaller than the case where the pattern is not formed (the case where the diffusion layer is formed on the entire surface), and is smaller than the actual inkjet. The in-wafer / inter-wafer variation at a displacement of 0.2 to 0.3 μm, which is about the same as the gap depth of the head, is 2 in the case of no pattern.
While it was about 0%, when the pattern was formed, it was 10% or less, and it was confirmed that the displacement amount at the same pressure was smaller than that without the pattern.

The surface roughness of the etching stop surface of the movable plate 10 is about 10 nm in the case of no pattern, whereas it is 5 nm or less in the case of the diffusion layer pattern shown in FIG. 5 or FIG. Confirmed that there is.

From these facts, it is possible to suppress the occurrence of dislocations which affect the thickness of the movable plate and the internal stress by forming the concave shape / boron concentration pattern on a part of the boron diffusion surface of the silicon substrate. As a result, it can be seen that the variation in the flexural rigidity of the movable plate within the wafer / between the wafers is reduced and the rigidity is increased.

In this embodiment, boron is used as the dopant. However, when a substance having a larger covalent atomic radius than silicon is used as the dopant, the internal stress of the movable plate becomes compressible. Since the flexure occurs naturally and is unsuitable as a movable plate of an ink jet head, it is preferable that a tensile internal stress acts even from the viewpoint of rigidity.

Next, another embodiment of the present invention will be described with reference to FIG.
0 and FIG. FIG. 10 is an explanatory plan view of the ink jet head according to the embodiment, and FIG. 11 is an explanatory sectional view of the head along the longitudinal direction of the diaphragm. In this embodiment, the high-concentration p-type impurity diffusion surface pattern has another function of the ink jet head in addition to the effect of suppressing dislocation in the diffusion layer portion.

That is, in this embodiment, the movable plate 10 of the pressurized liquid chamber 6 is formed by making the concave portion 22 of the diffusion surface formed by the method shown in FIG. 5 function as a gap connection chamber 40 communicating with each gap 16. The individual gaps 16 for driving are connected. In this case, the movable plate 10 is configured to be sandwiched between the left and right gap connection chambers 40.

As described above, by forming the gap connection chamber 40 with the high-concentration p-type impurity diffusion surface pattern in the flow path substrate 1, there is little restriction on the chip area, and the gap connection chamber is formed in the electrode substrate 3. The volume of the gap connection chamber can be increased as compared with the case. Thereby, the movable plate 1
The effect of the pressure increase in the gap 16 due to the displacement of 0 can be reduced, and the movable plate 10 can be driven at a low voltage. Also, in the depressurization gap, if there is a slight outgassing due to the volume effect, the influence can be made smaller than in the case where the individual gaps 16 are independent, and variation between heads can be suppressed. it can.

Next, steps for manufacturing the ink jet head of the above embodiment will be described with reference to FIGS. This step is a manufacturing step in which a non-diffused portion is formed by the method shown in FIG. 6 and the non-diffused portion is formed by etching as an ink supply port for supplying ink from the electrode substrate side. FIG. 14 is an explanatory plan view showing the position of the non-diffusion portion 25 on the substrate / chip.

As shown in FIG. 11A, the flow path substrate 1 having the non-diffusion portion 25 at the portion serving as the back surface supply port is formed together with the high-concentration boron diffusion layer 23 by the method shown in FIG. If necessary due to problems such as the surface roughness of the bonding surface, the surface of the diffusion surface is polished thinly and, for example, 100
Laminate at 0 ° C / 2 hours.

Thereafter, the flow path substrate 1 is polished thinly so that the depth of the pressurized liquid chamber becomes 100 μm or less as shown in FIG. After a silicon nitride film 51 (which becomes the silicon nitride film 12a in FIG. 3) to be an etching mask layer of potassium hydroxide is formed on the entire surface of the formed substrate, a mask pattern 52 (FIG. Of silicon nitride film 12b)
To form

Then, as shown in FIG.
Etching is performed with a potassium hydroxide aqueous solution of about 40 wt%, the etching is stopped at the oxide film on the bonding surface of the electrode substrate, and then the oxide film 3a is removed with hydrofluoric acid.

Next, as shown in FIG. 12A, the silicon nitride film 51 is patterned to form an etching mask pattern 54 of a pressurized liquid chamber and a common liquid chamber on the surface of the flow path substrate 1, and b) 10 to 40% as shown
After etching with a potassium hydroxide aqueous solution of about 20 to 20%, a saturated amount of alcohol was added as shown in FIG.
The portion where boron was diffused with a 35 wt% aqueous potassium hydroxide solution is left to form the movable plate 10. Non-diffusion portion 25 that does not diffuse boron corresponding to ink supply path 18
The portion is etched and the ink supply path 18 penetrates.

Thereafter, as shown in FIG. 4D, an opening is formed by dry etching for taking out an electrode after dicing the silicon substrate into ink jet head chips, and the nozzle plate 4 is bonded. .

Although an example in which the non-diffusion portion 25 is formed by the method shown in FIG. 6 is described here, the flow path substrate manufactured by the method shown in FIG. 6 or the flow substrate manufactured by the method shown in FIG. An ink jet head using a printed circuit board can be manufactured in the same manufacturing process.

Next, still another embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of a main part of the inkjet head according to the embodiment along the lateral direction of the diaphragm. In this embodiment, a gap 16 for displacing the movable plate 10 by the method shown in FIG. 7 is formed as a diffusion surface recess 60 on the flow channel substrate 1 side, not on the electrode substrate 3 side, and is diffused. High concentration p-type boron diffusion layer 61
Is a movable plate 10.

The electrode substrate 3 is a flat substrate on which no electrode forming groove (recess) is formed, and the individual electrodes 15 are formed on the oxide film 3a of the electrode substrate 3 so that the flow path substrate 1 Are joined.

In this embodiment, since the diffusion surface recess 60 for forming the gap 16 on the flow path substrate 1 side is formed by removing the thermal oxide film and the oxide film as described above, the gap shape with little variation is formed. Can be formed.

Next, an example of the ink jet recording apparatus according to the present invention will be described with reference to FIGS. FIG. 16 is a perspective view of the recording apparatus, and FIG. 17 is a side view of a mechanism of the recording apparatus. This inkjet recording apparatus includes a carriage movable in the main scanning direction inside a recording apparatus main body 111, a recording head including an inkjet head according to the present invention mounted on the carriage,
A printing mechanism 112 including an ink cartridge for supplying ink to the recording head, etc.
A paper feed cassette (or a paper feed tray) 11 capable of stacking a large number of papers 113 from the front side is provided at a lower portion of 1.
4 can be inserted and removed freely.
After the manual feed tray 115 for manually feeding the paper 13 can be opened, the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in, and a desired image is recorded by the printing mechanism 112. Then, the paper is discharged to a paper discharge tray 116 mounted on the rear side.

The printing mechanism 112 slides the carriage 123 in the main scanning direction (the direction perpendicular to the paper surface in FIG. 15) with the main guide rod 12 and the sub guide rods 122, which are guide members that are horizontally mounted on left and right side plates (not shown). The carriage 123 is arbitrarily held, and a plurality of ink ejection ports are provided on the carriage 123. The head 124 includes an inkjet head that ejects ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). They are arranged in a direction crossing the main 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.

The ink cartridge 125 has an upper air port communicating with the atmosphere, a lower supply port for supplying ink to the ink jet head, and a porous body filled with ink inside. The ink supplied to the inkjet head by the capillary force is maintained at a slight negative pressure.

Although the heads 124 of the respective colors are used here as recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used. Furthermore, the inkjet head used as the head 124 may be a piezo-type inkjet head that pressurizes ink through a movable plate that forms a liquid chamber wall with an electromechanical transducer such as a piezoelectric element. An electric inkjet head is used.

The carriage 123 is slidably fitted to the main guide rod 112 on the rear side (downstream side in the paper transport direction), and is slidable on the front side (upstream side in the paper transport direction) on the slave guide rod 122. It is placed on. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a driving pulley 128 and a driven pulley 129 which are driven to rotate by a main scanning motor 127. , And the carriage 123 is reciprocated by the forward and reverse rotation of the main scanning motor 127.

On the other hand, in order to transport the paper 113 set in the paper feed cassette 114 to the lower side of the head 124, a paper feed roller 131 and a friction pad 132 for separating and feeding the paper 113 from the paper feed cassette 114,
Guide member 133 for guiding the sheet 3 and the fed sheet 11
A transport roller 134 that reverses and transports the sheet 3, a transport roller 135 pressed against the peripheral surface of the transport roller 134, and a tip roller 136 that defines an angle at which the paper 113 is sent out from the transport roller 134 are provided. Transport roller 1
The sub-scanning motor 137 is driven to rotate via a gear train.

A print 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 moving range of the carriage 113 in the main scanning direction. I have. 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 that are driven to rotate to transport the paper 113 in the paper discharge direction. Roller 143 and spur 1
44, and guide members 145, 146 forming a paper discharge path
And are arranged.

At the time of recording, the recording head 124 is driven in accordance with an image signal while moving the carriage 113, thereby ejecting ink onto the stopped paper 113 to record one line and recording the paper 113 by a predetermined amount. After transport, the next line is recorded. Upon receiving a recording end signal or a signal that the rear end of the sheet 113 has reached the recording area, the recording operation is terminated and the sheet 113 is discharged.

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 of the carriage 113 in the moving direction. The recovery device 147 has cap means, suction means, and cleaning means. The carriage 123 is moved to the recovery device 147 side during the 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.
Also, by ejecting ink that is not related to printing during printing or the like, the ink viscosity of all the ejection ports is kept constant,
Maintain stable discharge performance.

When a discharge failure occurs, the discharge port of the head 124 is sealed by a capping means, bubbles and the like are sucked out of the discharge port by a suction means through a tube, and ink, dust, etc. adhered to the discharge port surface. Is removed by the cleaning means, and the ejection failure is recovered. Also,
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.

In the above embodiment, an electrostatic ink jet head has been described as an example of an ink jet head, but the present invention can be similarly applied to a piezo ink jet head in which a movable plate is deformed by a piezoelectric element. Also,
In addition to the inkjet head, a microactuator having a movable plate as a movable portion, for example, a micropump,
The present invention can be similarly applied to a micro switch (micro relay), a multi-optical lens actuator (micro mirror), a micro flow meter, a pressure sensor, and the like.
Further, for example, the present invention can be applied to a droplet discharge head that discharges a liquid resist for patterning as a droplet discharge head other than the inkjet head.

Further, in the above embodiment, the present invention is applied to the side shooter type ink jet head in which the movable plate displacement direction and the ink droplet ejection direction are the same.
The present invention can be similarly applied to an edge shooter type ink jet head in which the movable plate displacement direction and the ink droplet ejection direction are orthogonal.

[0064]

As described above, according to the droplet discharge head of the present invention, the high-concentration impurity diffusion layer forming the movable plate has a non-uniform depth distribution at least partially within the silicon substrate surface. Alternatively, since the structure is discontinuous, occurrence of dislocation in the diffusion portion can be suppressed, and a movable plate having high rigidity can be formed uniformly.

Here, a concave portion is provided in a part of the surface of the diffusion surface of the silicon substrate to form the high-concentration p-type impurity diffusion layer serving as a movable plate, so that the diffusion layer distribution of the p-type impurity forming the movable plate is obtained. Is partially uneven on the silicon substrate surface /
Discontinuous portions can be easily formed.

By providing a non-diffusion portion or a portion having a diffusion portion having a different concentration distribution on the surface of the silicon substrate on which the high concentration p-type impurity diffusion layer is formed, the diffusion layer distribution of the p-type dopant forming the movable plate is provided. However, it is possible to easily form a portion that is partially non-uniform / discontinuous on the silicon substrate surface.

Further, when the p-type dopant is a substance having a smaller atom covalent bond radius than that of silicon atoms, the movable plate has a tensile internal stress, thereby enabling stable high-speed driving.

In addition, by having an electrode facing the movable plate and discharging the liquid droplet by displacing and deforming the movable plate with electrostatic force, low voltage driving and power saving driving can be performed. In this case, a plurality of pressurized liquid chambers are formed in the silicon substrate, and a non-uniform or discontinuous portion of the high-concentration p-type impurity diffusion layer connects individual gaps formed between the movable plate and the counter electrode. Since the connection chamber also functions as a connection chamber, a high-performance droplet discharge head can be manufactured at lower cost.

A plurality of pressurized liquid chambers are formed in the silicon substrate, and the non-uniform or discontinuous portion of the high-concentration p-type impurity diffusion layer forms a flow path for supplying liquid to the pressurized liquid chamber. This also makes it possible to manufacture a high-performance droplet discharge head at lower cost.

Alternatively, it is possible to manufacture a low-cost head having a small gap shape even when the non-uniform portion of the high-concentration p-type impurity diffusion layer forms a gap between the movable plate and the counter electrode. Can be.

The ink jet recording apparatus according to the present invention
Since the droplet discharge head according to the present invention is mounted as an inkjet head that discharges ink droplets, a recording device capable of performing high-quality recording at low running cost can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an inkjet head according to the present invention.

FIG. 2 is an explanatory plan view of the head excluding a nozzle plate;

FIG. 3 is a schematic cross-sectional explanatory view of the head along a movable plate longitudinal direction.

FIG. 4 is a schematic cross-sectional explanatory view of the head along a short direction of a movable plate.

FIG. 5 is an explanatory view illustrating a first example of a step of forming a high-concentration p-type impurity diffusion layer of the head.

FIG. 6 is an explanatory view for explaining a second example of a step of forming a high-concentration p-type impurity diffusion layer of the head.

FIG. 7 is an explanatory view illustrating a third example of a step of forming a high-concentration p-type impurity diffusion layer of the head.

FIG. 8 is an explanatory diagram for explaining the operation and effect according to the present invention;

FIG. 9 is an explanatory diagram for explaining the operation and effect of the present invention.

FIG. 10 is an explanatory plan view excluding a nozzle plate of an inkjet head according to another embodiment of the present invention.

FIG. 11 is a schematic cross-sectional explanatory view of the head along the longitudinal direction of the movable plate.

FIG. 12 is an explanatory diagram for explaining a manufacturing process of the head in FIG. 1;

FIG. 13 is an explanatory diagram provided for the continuation of FIG. 12;

FIG. 14 is an explanatory top view for explaining the manufacturing process;

FIG. 15 is an explanatory cross-sectional view of an inkjet head according to still another embodiment of the present invention, taken along a lateral direction of a movable plate.

FIG. 16 is an explanatory perspective view illustrating a mechanism of the inkjet recording apparatus according to the invention.

FIG. 17 is an explanatory side view of the recording apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flow path substrate, 2 ... High concentration boron diffusion layer, 3 ... Electrode substrate, 4 ... Nozzle plate, 5 ... Nozzle, 6 ... Pressurized liquid chamber, 8 ... Common ink chamber, 10 ... Movable plate, 15 ... Electrode.

Claims (9)

[Claims] 1. A high-density nozzle formed on a silicon substrate, comprising: a nozzle for discharging liquid droplets; a pressurized liquid chamber to which the nozzle communicates; and a movable plate forming a wall surface of the pressurized liquid chamber. In the droplet discharge head formed of a p-type impurity diffusion layer, the high-concentration impurity diffusion layer forming the movable plate has a non-uniform or discontinuous depth distribution at least partially within the silicon substrate surface. A droplet discharge head characterized in that: 2. The droplet discharge head according to claim 1, wherein the high-concentration p-type impurity diffusion layer serving as a movable plate is formed by forming a concave portion on a part of the diffusion surface of the silicon substrate. A droplet discharge head characterized in that: 3. The droplet discharge head according to claim 1, wherein a non-diffusion portion or a portion having a diffusion portion having a different concentration distribution is provided on a surface of the silicon substrate on which the high concentration p-type impurity diffusion layer is formed. A droplet discharge head characterized in that: 4. The droplet discharge head according to claim 1, wherein the p-type impurity is a substance having a smaller atom covalent bond radius than a silicon atom. 5. The droplet discharge head according to claim 1, further comprising an electrode facing the movable plate, wherein the movable plate is displaced and deformed by electrostatic force to discharge the droplet. A droplet discharge head characterized by the above-mentioned. 6. The droplet discharge head according to claim 5, wherein a plurality of pressurized liquid chambers are formed in the silicon substrate, and the high-concentration p-type impurity diffusion layer has a non-uniform or discontinuous portion. A droplet discharge head, which also serves as a connection chamber that connects individual gaps formed between the movable plate and the counter electrode. 7. The droplet discharge head according to claim 1, wherein a plurality of pressurized liquid chambers are formed in a silicon substrate, and the high-concentration p-type impurity diffusion layer has a non-uniform or discontinuous structure. A liquid discharge head, wherein a portion forms a flow path for supplying a liquid to the pressurized liquid chamber. 8. The droplet discharge head according to claim 1, wherein the non-uniform portion of the high-concentration p-type impurity diffusion layer forms a gap between the movable plate and the counter electrode. A droplet discharge head characterized by being formed. 9. An ink jet recording apparatus equipped with an ink jet head for discharging ink droplets, wherein the ink jet head is the liquid drop discharging head according to any one of claims 1 to 8. .