JP2000309098A - Ink-jet printing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high reliable ink-jet printer head capable of ejecting an ink stably over a long time, with a pressure accumulation partition wall having a good adhesion property with respect to a substrate. SOLUTION: A common electrode 21, a common electrode feeding terminal, an individual wiring electrode 23, a head generating part 25, a driving circuit 26, and a driving circuit terminal are formed on a chip substrate 20. An eliminating part hole 28 is formed in an electrode connecting wiring part 21-1 in a part facing an opening (ink inlet opening) of a section part 32 formed by a sealing partition wall 31-2 and a section partition wall 31-3 surrounding the heat generating part 25 from three directions. A pressure accumulation partition wall 31-4 is provided by direct contact of a part or the entirety of an upright surface with a passive state film on the chip substrate 20 surface exposed in the eliminating part hole 28. Even if the electrode film is an inactive metal, the adhesion force of the pressure accumulation partition wall 31-4 to be contacted directly with the passive state film on the chip substrate 20 surface via the eliminating part hole 28 so that the risk of lacking or collapse in a curing step or another step can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer head which can discharge ink with high energy efficiency, has high reliability, and is easy to manufacture.

[0002]

2. Description of the Related Art In recent years, ink jet printers have been widely used. The printer using the ink jet system includes a pressurizing unit for pressurizing and discharging ink. The configuration of the pressurizing unit includes a thermal jet system in which ink droplets are ejected by the force of air bubbles and a piezo system in which ink droplets are ejected by deformation of a piezoresistive element (piezoelectric element).

[0003] The printing method using these structures is a process in which ink as a color material is formed into ink droplets and ejected directly to recording paper. Energy is low, colorization is easy by mixing inks, print dots can be made small, high image quality, and there is no waste in the amount of ink used for printing and excellent cost performance. This is a printing method widely used as a personal printer.

[0004] The above-mentioned thermal jet system has two configurations depending on the ejection direction of ink droplets. That is, there are a configuration in which ink is ejected in a direction parallel to the heat generating surface of the heat generating unit as a pressurizing unit, and a configuration in which ink is discharged in a direction perpendicular to the heat generating surface of the heat generating unit. Above all, those that discharge ink droplets in the direction perpendicular to the heat generating surface of the heat generating portion are called roof shooter type thermal inkjet heads, and that are configured to discharge ink in a direction parallel to the heat generating surface of the heat generating portion. It is known that power consumption is extremely small compared to

[0005] As a method of manufacturing this roof shooter type thermal ink jet head, a large number of wafers (for example, 90 wafers having a diameter of 6 inches or more) partitioned on a silicon wafer are used.
Or more) on a chip substrate using silicon LSI forming technology and thin film forming technology, a plurality of heating units, a driving circuit for individually driving them, and a corresponding ink discharge nozzle are monolithically integrated. Is formed.

FIG. 8A is a plan view schematically showing the basic structure of a roof shooter type thermal ink jet head produced in this manner, and FIG. 8B is a plan view of the same.
FIG. 3A is a sectional view taken along the line AA ′ of FIG. FIG. 2A shows the orifice plate 8 in a transparent manner. As shown in FIGS. 1A and 1B, the thermal ink jet head 1 is connected to both ends of a heating resistor thin film 3 formed on a chip substrate 2 and heating portions 4 of the heating resistor thin film 3. Provided with the individual wiring electrode 5 and the power supply common electrode 6, the partition wall 7 laminated thereon, and the orifice plate 8 further laminated thereon, and the ink discharge nozzle 9 is formed on the orifice plate 8. Have been.

The partition 7 is provided on a seal partition (not shown) disposed at an end of the power supply common electrode 6 for sealing the ink in the ink flow path 11 from the outside, and disposed on the individual wiring electrode 5. The heat generating portion 4 includes a seal partition 7a and a partition 7b extending from the seal partition 7a between the heat generating portions 4 to partition the heat generating portions 4. Heating part 4 above
Is arranged in a U-shaped partition section formed by the seal partition wall 7a and the partition partition wall 7b, and is separately partitioned from other adjacent heat generating sections 4. In addition, an ink flow path 10 having a height corresponding to the thickness of the partition wall 7 is formed on the opening side of the partition section in parallel with the direction in which the heat generating sections 4 are arranged.

FIGS. 9 (a) to 9 (d) are diagrams showing an operation state when the thermal ink jet head is driven to generate heat. FIG. 9 (a) shows the configuration shown in FIG. 8 (b). Reposted. However, the ink 11 is always supplied to the ink flow path 10. Further, when clogging or the like is restored prior to the printing operation, a cleaning liquid may be supplied.

First, as shown in FIG. 1B, the heating section 4 is caused to generate heat by energization in accordance with the image information.
When a nuclear bubble is generated above, the nuclear bubbles are united to generate a film bubble 12. Then, as shown in FIG. 3 (c), the film bubble 12 is adiabatically expanded to form a larger film bubble 12a.
The ink 11a is pushed out from the ink discharge nozzle 9 by pushing the surrounding ink. The extruded ink 11a is extruded by a further expanded film bubble 12b of the film bubble 12a to form an ink droplet 11b as shown in FIG. Is discharged. After that, the grown film bubble 12b is shrunk by the heat of the surrounding ink, and finally the bubble disappears, and the next heating of the heating section 4 is awaited.
This series of steps is performed instantaneously.

By the way, in the basic structure of the thermal ink jet head shown in FIGS. 8A and 8B, as shown in the operation state diagram of FIG. There is a problem in that the partition wall 7a and the partition partition wall 7b spread and diffuse toward the opening (ink inlet) side of the partition, and the efficiency of pressurized energy to be concentrated on the ink discharge nozzle 9 is reduced. Therefore, it has been proposed to form a projection of a pressure reservoir near the opening of the partition in order to prevent the above-described decrease in the pressure energy efficiency.

FIG. 10 is a plan view schematically showing an improved structure of a thermal ink jet head proposed to prevent a decrease in the pressurizing energy efficiency.
(b) is a sectional view taken along the line BB 'of (a). Figures (a), (b)
As shown in (1), this configuration is a structure in which an isolated partition 13 is erected near the ink inlet, which is the opening of the partition, and this is used as a pressure reservoir. The partition wall 13 of the pressure reservoir prevents the pressurized energy at the time of ejection from escaping in the direction of the ink inflow port, so that the energy efficiency at the time of ejecting the ink is improved.

[0012]

However, the partition wall 13 of the pressure reservoir is isolated from any surrounding structure, and the orifice plate 8 is not yet formed in the developing and curing (dry curing, firing) manufacturing steps. Partition walls 13 because they are not laminated
Is like a solitary island. The spacing between the partitioning sections that individually partition the heat generating sections 4 is about 40 μm, and the width of the opening is about 30 μm. Plane size is 10
It is about 20 μm square.

The partition having such a fine structure is generally patterned by using a photosensitive resin as a material of the partition and using a mask by photolithography. As the photosensitive resin, a photosensitive polyimide particularly excellent in heat resistance is often used. When the photosensitive polyimide is laminated on the substrate to form a partition, the adhesion strength between the substrate and the photosensitive polyimide is determined by the oxygen of the carbonyl group forming the skeleton of the photosensitive polyimide and the substrate surface serving as a base for lamination. It has been found that it depends on the intermolecular force of oxygen with oxygen present in oxygen.

However, in order to prevent corrosion caused by ink flowing in contact with the individual wiring electrodes 5 and the power supply common electrode 6 which constitute the majority of the surface of the other substrate, an inert material such as Au is used. A stable and low-resistance metal material must be coated from the top of the electrode or used as an electrode from the beginning. Since the above-mentioned intermolecular force does not act on such an inert metal electrode, a photosensitive polyimide is used. There is a problem that the adhesion strength is weak and the above-mentioned island-shaped isolated partition walls 13 are easily dropped or collapsed.

In order to solve this problem, it is conceivable to increase the erected area of the partition wall so as to increase the adhesion of the partition wall. However, if this is done, the arrangement intervals of the heat-generating portions become large, and this has led to more and more market demands in recent years. The problem arises that goes against the flow of higher resolution, which is becoming stronger.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances,
An object of the present invention is to provide a highly reliable ink jet printer head which has good adhesion of a pressure reservoir partition to a substrate and can stably eject ink with good energy efficiency over a long period of time.

[0017]

According to the present invention, there is provided an ink jet printer head comprising a plurality of discharge nozzles for discharging a liquid under pressure in a predetermined direction, and a plurality of discharge nozzles formed on an insulating substrate so as to communicate with the respective discharge nozzles. A plurality of individual liquid chambers formed and provided with at least one opening, to which the liquid is supplied from the openings, and electrodes respectively arranged on the insulating substrate in the individual liquid chambers for applying a voltage A plurality of energy generating elements each comprising a membrane and an energy converter connected to the electrode membrane for generating pressure energy for discharging the liquid, and a common liquid for relaying the supply of the liquid to each of the individual liquid chambers A liquid chamber formed between the common liquid chamber and the respective openings of the individual liquid chambers, and provided in a lower layer of the electrode film. Configured with the contact upright been protrusions.

The lower layer of the electrode film is preferably, for example, an insulating substrate having a passivation film adhered to the substrate surface. Preferably, the projection is made of a polyimide resin, the substrate is a silicon substrate, and the passivation film is SiO2.

Further, the energy generating element is a heating element in which an electrode film is laminated on a heating resistor film, and a lower layer of the electrode film is laminated on an insulating substrate. The heat generating resistor film may be used.

Further, for example, as set forth in claim 5, the electrode film is made of an inert metal, and the projecting body is formed by removing the insulating film through a removal hole formed in the electrode film made of the inert metal. 8. An erecting member which is erected directly on the surface of the conductive substrate.
As described, it is preferable that the tip is formed in contact with the back surface of the orifice plate. Preferably, the inert metal is Au, for example.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the ejection nozzles include, for example, ink ejection nozzles 35 and the like.
The insulating substrate includes, for example, the chip substrate 20 and the like, and the liquid includes, for example, Y, M, C, and Bk inks.
The individual liquid chamber includes, for example, a partition 32, and the electrode film includes, for example, a connection wiring portion 21- connected to a heating portion of the common electrode 21.
1 and the like.
5, the common liquid chamber includes, for example, a common ink supply path 29, the liquid flow path includes, for example, an ink flow path 34, and the projection includes, for example, a pressure reservoir partition 3.
1-4.

FIG. 1A is a schematic diagram showing a state at an initial stage of forming on a silicon chip substrate in a series of manufacturing steps of an ink jet printer head (hereinafter, simply referred to as a print head) according to an embodiment. (B) is an enlarged view of a part of the plan view, and FIG. (C) is a view taken on line C- of FIG.
FIG. 3D is a sectional view taken along the line C-D of FIG. In these figures, one print head (same as the configuration of the monochrome inkjet head) of a full-color print head is shown for convenience of explanation, but such a print head is actually used as described later. Are multiple (usually 4
) Are formed on one substrate (silicon chip).

FIG. 2A is a schematic plan view schematically showing a state in an intermediate stage of the above series of manufacturing steps. FIG. 2B is an enlarged view of a part of FIG. 2C, and FIG. 2C is a sectional view taken along line EE ′ of FIG. 2B and FIG. It is FF 'sectional drawing of b).

FIG. 3A is a schematic plan view schematically showing a state at the final stage of the above-described series of manufacturing steps. FIG. 2B is an enlarged view of a part of FIG. 1C, and FIG. 2C is a sectional view taken along line GG ′ of FIG. 2B, and FIG. It is HH 'sectional drawing of b).

In this method of manufacturing a print head, first, as step 1, a drive circuit and its terminals are formed on a silicon substrate of 4 inches or more by an LSI forming process, and an oxide film having a thickness of 1 to 2 μm is formed as a passive film. Is formed, and then, in step 2, Ta (tantalum)-
A heating resistor film made of Si (silicon) -O (oxygen) and an electrode film made of Au or the like using W-Ti as a barrier layer are formed. Then, the electrode film and the heating resistor film are each patterned by photolithography technology, and a plurality of heating elements in which wiring electrodes are laminated on both sides of a region serving as a heating portion on the stripe-shaped heating resistor film are provided in a predetermined manner. They are formed in parallel at intervals. In this step, the position of the heat generating portion is determined.

Then, in the pattern formation of the wiring portion by the photolithography technique, a removed portion hole having a predetermined shape, which is a main part of the present invention, is formed in the common electrode. The removed portion hole is provided with an opening having a shape that is slightly larger than the installation surface of the pressure storage partition, in a portion corresponding to a region where a pressure storage partition described later is formed of the photomask forming the electrode wiring pattern. By patterning the electrode film by photolithography using a mask,
The common electrode is formed in the above-described shape at the above-described position.

FIGS. 1A to 1D show a state immediately after the above steps 1 and 2 are completed. That is, the common electrode 21 and the common electrode power supply terminal 2 are provided on the chip substrate 20.
2. Individual arrangement rows 23 'in which individual wiring electrodes 23 are arranged in parallel,
A heating section row 25 'in which heating sections 25 as energy generating elements are arranged in parallel, a drive circuit 26 and a drive circuit terminal 27 are formed. A substantially rectangular removal portion hole 28 is formed in each of the connection wiring portions 21-1 connected to the heat generation portion 25 of the common electrode 21, and the surface of the chip substrate 20 is exposed there.

Subsequently, as a step 3, the individual heating parts 25
A partition member made of an organic material such as photosensitive polyimide is formed to a height of about 20 μm by coating in order to form a partition corresponding to the above and an ink flow path, and after patterning this by photolithography, 300 ° C. to 400 ° C. Is applied (dry curing, baking) for 30 to 60 minutes to form and fix a 10 μm-high partition wall made of the photosensitive polyimide on the chip substrate. Further, as a step 4, a groove-like common ink supply path is formed on the upper surface of the chip substrate (the surface on which the heating resistor film and the electrode film are formed) by wet etching or sandblasting, or the like.
Further, an ink supply hole communicating with the common ink supply path and opening on the lower surface of the substrate is formed.

FIGS. 2 (a) to 2 (d) show a state immediately after the above-mentioned steps 3 and 4 are completed. That is, the common ink supply path 29 and the ink supply hole 30 in a groove shape are formed, and the common electrode 2 located on the left side of the common ink supply path 29 is formed.
Seal partitions 31-1 and 31-2 for sealing ink from the outside are formed in one portion and a portion where the individual wiring electrode 23 on the right side is provided.
A partition wall 31-3 extending from each of the heat-generating portions 25 to the corresponding heat-generating portion 25 is formed. Further, a pressure storage partition 31-4 is formed in the removed portion hole 28 of the connection wiring portion 21-1 of the common electrode 21.

If one of the seal partition walls 31-2 and the partition partition wall 31-3 formed around the heat generating portion 25 is a comb body, the other partition partition wall 31-3 is A fine ink pressurizing chamber having a shape corresponding to the teeth of a comb, and a heat-generating portion 25 located at a portion corresponding to a root between the teeth, with a partition wall 31-3 having a tooth shape of the comb serving as a partition wall. Are formed by the number of the heat generating portions 25. Then, close to the opening (ink inlet) of the partitioning portion 32 so as to face the opening, the pressure reservoir partition wall 31-4 exposes at least a part of the lower installation surface to the inside of the removing portion hole 28. And stands upright in direct contact with the surface of the chip substrate 20.

Then, in step 5, an orifice plate of a polyimide film having a thickness of 10 to 30 μm is coated on one surface with a very thin thermoplastic polyimide as an adhesive, for example, to a thickness of 2 to 5 μm. The uppermost layer of the structure, that is, the partition 31 (31-1, 31-2, 31-3, 3
The orifice plate is fixed by applying pressure while heating at 290-300 ° C. Then N
A metal film for mask, such as i, Cu or Al, having a thickness of about 0.5 to 1 μm is formed.

Further, as a step 6, the metal film on the orifice plate is patterned to form a mask for selectively etching polyimide, and then the orifice plate is dry-etched by a helicon wave or the like to form the metal film. A plurality of ink discharge nozzles (orifices) are formed at once by forming holes of 31 μmφ to 29 μmφ according to the mask.

FIGS. 3A to 3D show a state immediately after the above-described steps 5 and 6 are completed. That is, the orifice plate 33 is connected to the common power supply terminal 22 and the drive circuit terminal 27.
, And covers the entire area except for the part of the seal partition wall 31-2.
And partition section 3 formed by partition wall 31-3
2 also covers the upper part and becomes a fine ink pressurization chamber having a height corresponding to the thickness (height) of the partition 31 of 10 μm, and has an opening directed toward the common ink supply path 29. In addition, an ink flow path 34 having a height of 10 μm is formed to connect the openings of the partition sections 32 and the common ink supply path 29. The ink supplied from the outside to the ink flow path 34 via the ink supply hole 30 and the common ink supply path 29 is configured to flow into the partition 32 so as to go around the respective pressure storage partitions 31-4. ing.

The orifice plate 33 has a heat generating portion 2
An orifice, that is, an ink discharge nozzle 35 is formed by dry etching in a portion opposed to 5. As a result, a mono-color ink-jet head 36 having many ink discharge nozzles 35 in one line is completed. still,
FIG. 6A shows 36 ink ejection nozzles 35, but in reality, a large number such as 64, 128, and 256 are formed according to the design policy.

Further, by attaching the orifice plate 33 and then processing the ink discharge nozzles 35 in accordance with the pattern of the base, that is, the position of the heat generating portion 25, the orifice plate previously processed with the ink discharge nozzles 35 is used. This is a much more productive and practical method than laminating 33. In the case of dry etching, the selectivity between the resin and the metal film can be approximately 100 by using a metal film such as Ni, Cu, or Al for the mask. Therefore, it is sufficient to form a mask with a metal film of 1 μm or less to etch a 29 to 31 μm polyimide film.

The processing up to this point is performed in the state of a silicon wafer. Finally, as a step 7, the silicon wafer is cut along a scribe line using a dicing saw or the like, divided into individual chip substrate units, die-bonded to a mounting substrate, and connected to terminals. A print unit in practical units is completed.

As described above, one row of ink ejection nozzles 35
The print head 36 having the structure of a mono-color, that is, a monochrome print head, is normally used in full-color printing. However, in the case of full-color printing, three subtractive primary colors of yellow (Y), magenta (M), and cyan (C) are used. In addition to the colors, black (Bk) dedicated to the black portions of characters and images is added, and a total of four colors of ink are required. Therefore, at least four nozzle rows are required. According to the above-described manufacturing method, it is possible to arrange four mono-color print heads 36 side by side to form a monolithic structure, and the positional relationship of the ink discharge nozzles 35 between the print heads can be accurately determined by today's semiconductor manufacturing technology. It is possible to arrange.

FIG. 4A shows the above-described monocolor print head 3.
6 is a diagram showing a state in which four full color print heads 6 are arranged to form a full-color print head 38. FIG. FIG. 4B shows the mono-color print head 36 shown in FIG. 3A in which the four mono-color print heads 36 are arranged in a line as shown in FIG. 4
This shows a state in which the process has been completed.

As shown in FIGS. 4A and 4B, the full-color print head 38 includes four mono-color print heads 36.
(36a, 36b, 36c, 36d) are arranged side by side. For example, Y ink is supplied from the common ink supply path 29a to each partition 32 of the monocolor print head 36a, and M ink is supplied from the common ink supply path 29b. The C ink is supplied to the individual sections 32 of the color print head 36b, the C ink is supplied to the individual sections 32 of the monocolor print head 36c from the common ink supply path 29c, and the Bk ink is supplied from the common ink supply path 29d. It is supplied to the individual partitions 32 of the monocolor print head 36d.

As described above, in the full-color print head 38 having the above configuration according to the present embodiment, when the wiring pattern of the electrode film is formed by the photolithography technique in the step 2 as described above, the connection wiring portion to the heating portion 25 of the common electrode 21 is formed. A rectangular removal portion hole 28 is formed in 21-1 to expose the silicon oxide film layer on the surface of the chip substrate 20, and a predetermined portion of the lower surface is directly in contact with the exposed silicon oxide film layer in step 3. Thus, the pressure storage partition 31-4 is formed.

The silicon oxide film layer has an extremely good adhesion to the photosensitive polyimide as a material of the partition walls. Therefore, the pressure reservoir partition walls 31-4 are erected in a state of firmly adhering to the chip substrate 20. . Thus, not only during the development in the step 3 but also in the curing step, which is the subsequent processing, and in the manufacturing steps after the step 4, the pressure storage partition 31- is also used when the ink jet printer head is actually used.
Since defects such as dropping or collapse of the ink jet head 4 can be eliminated, a highly reliable ink jet printer head that can stably and properly discharge ink with high energy efficiency can be put on the market.

The passivation film is not limited to SiO.sub.2 (silicon oxide), but is also preferably applied to SiN (silicon nitride), PSG (phosphorous silicate glass), etc., which have excellent adhesion to a polyimide resin. can do.

Here, the results of measuring the adhesion strength between the photosensitive polyimide and the passivation film on the surface of the chip substrate are shown.
FIG. 5A is a diagram showing a cross section of a sample for measuring the adhesion strength, and FIG. 5B is a diagram showing a state where the adhesion strength is strong.
(c) is a diagram showing a state where the adhesion strength is weak. First, the figure
As shown in (a), a base surface layer film 42 serving as a base of a partition standing upright on a silicon wafer substrate 41 is formed, and a partition material 43 is formed thereon in a stripe pattern. Then, the orifice plate material film 44 is bonded by hot pressing.

Next, as shown in FIG. 6B, the orifice plate material film 44 is peeled off in a 90 ° direction from the substrate surface, and its tensile strength is measured. At this time,
As shown in (b), if peeling occurs at the interface between the partition material 43 and the orifice plate material film 44, the strength measured and read at this time is the adhesive strength between the partition material 43 and the orifice plate material film 44. That is, the adhesion strength between the partition wall material 43 and the base surface layer film 42 is unknown. However, it can be said that the adhesion strength is at least higher than the read strength. This peeling mode is referred to as a peeling mode A.

On the other hand, as shown in FIG.
When peeling occurs at the interface between the base material 3 and the base surface film 42, the measured and read strength is the partition material 43 and the base surface film 4.
2 is the adhesion strength. This peeling mode is called peeling mode B
And

In the above measurement, a kind of photosensitive polyimide (commercially available) was formed to a thickness of 10 μm as a partition wall material, and a kind of 31 μm thick film (commercially available) was used as an orifice plate material film. When the underlayer surface film 42 was SiO2, the peeling mode A was observed, and the adhesion strength measured at this time was "106 gf / cm (or more)". When the underlying surface layer film 42 is made of Au, the peeling mode B is observed, and the measured adhesion strength is “5”.
gf / cm ". In other words, it was found that the adhesion strength of the partition wall material was at least 20 times larger when the partition wall material was photosensitive polyimide when the base surface layer film was made of SiO2 and Au when the partition walls were laminated. did.

That is, as compared with the case where the pressure reservoir partition wall 31-4 of the photosensitive polyimide is directly formed on the electrode wiring of Au (the connection wiring section 21-1 to the heating section of the common electrode 21).
It has been found that when the pressure reservoir partition wall 31-4 is formed so as to be in contact with the silicon oxide film on the surface of the chip substrate 20 exposed in the removal portion hole 28, a 20-fold adhesion strength can be obtained.

The above-described structure of the present invention in which the removing portion hole 28 formed in the connection wiring portion 21-1 and the pressure reservoir partition wall 31-4 are formed on the removing portion hole 28 is based on the above test results. It was devised above.

As a result, Au, which had the best performance as an electrode but had a practical difficulty due to poor adhesion to the partition, was removed by the present invention shown in FIGS. With the configuration of the electrode having the hole 28, it can be easily used as an electrode.
In this case, it is not necessary that all the standing surfaces of the pressure storage partition walls 31-4 are in contact with the exposed substrate surface, and the pressure storage partition walls 31-4 have at least 20 times the adhesion force to Au. If a part of the erected surface is in contact with the exposed substrate surface, sufficient adhesion to prevent chipping or collapse can be obtained.

As described above, since only the hole in which a part of the electrode portion in contact with the upright surface of the pressure reservoir partition wall 31-4 is removed is effective, the wiring resistance is particularly increased by removing the electrode metal. In order to avoid this, it is desirable that the area from which the electrode metal is removed is as small as possible, and the minimum area that can maintain the strength sufficient to prevent the pressure reservoir partition wall 31-4 from falling off or the like is removed. In such a case, it has been confirmed that an area approximately equal to the square of the height of the pressure reservoir partition wall 31-4 may be removed.

Of course, if there is no problem in the wiring resistance, a structure may be used in which all the electrode metal in the portion where the standing surface of the pressure reservoir partition 31-4 contacts is removed. 6 (a) to 6 (f) are views showing the relationship between the shape of the pressure reservoir partition wall and the removal hole of the underlying electrode metal film. Note that FIG. 2A shows only the main parts of the configuration shown in FIGS. 2B and 2C for comparison, and FIG. 2B and FIG. The same numbers are assigned and shown. The configuration shown in FIG. 6A is a rectangular shape in which a part of the electrode metal (connection wiring portion 21-1 to the heat generating portion of the common electrode 21) is removed from the portion where the standing surface of the pressure storage partition 31-4 contacts. And a pressure reservoir partition 31-4 having a substantially rectangular cross section is provided upright so as to straddle the rectangular removing portion hole 28 in the lateral direction.

On the other hand, the configuration of FIG.
(a) A pressure reservoir partition 31-4b having a substantially square cross section as in FIG.
Is formed in the removed portion hole from which all of the electrode metal on the erected surface has been removed. The other FIGS. 6 (c) to 6 (f) are also the same.
Similarly to (b), the pressure reservoir partition walls (31-4c, 31-4d, 31-4e, 31-) are placed in the removal holes from which all the electrode metal has been removed at the portions where the standing surfaces of the pressure reservoir partition walls are in contact. 4
The configuration in which f) is erected is shown.

Among them, FIG. 3 (c) shows that the pressure storage partition 31-4c has a triangular plane cross section so that the ink can easily flow into the partition 32 and the pressure at the time of ink discharge is reduced. It is a thing that did not escape. Also, FIG.
Has a trapezoidal flat cross section of the pressure storage partition 31-4d, which also makes it easy for ink to flow in and does not release the pressure at the time of ink discharge.

The pressure storage partition 31-4e shown in FIG.
Is formed by forming a recess on the surface of the trapezoidal heat generating portion 25 side in FIG. 3D, and this shape places emphasis on preventing pressure from escaping during ink ejection. Then, FIG.
The pressure reservoir partition 31-4f shown in FIG. 3 is rounded as a whole with the shape shown in FIG. 3 (e) as the original shape, and this shape places emphasis on the ease of ink inflow.

It should be noted that, even if the shape of the pressure reservoir partition is not substantially square as shown in FIG. 5 (a), the shape of the pressure reservoir partition is variously changed as shown in FIGS. It goes without saying that the electrode metal at the portion where the standing surface of the pressure reservoir partition comes into contact may be removed not only the whole surface but only a part thereof. Further, in FIGS. 7A to 7F, the pressure reservoir partition walls are formed in the same shape in the same print head, but the present invention is not limited to this. As long as the pressure reservoir partition walls having different shapes can be formed, the pressure reservoir partition walls having different shapes may be mixed in the same print head.

FIG. 7A is a plan view showing a structure in which such pressure reservoir partitions having different shapes coexist in the same print head, and FIG. 7B is a sectional view taken along the line JJ 'of FIG. It is.
As shown in FIGS. 3A and 3B, the print head 45 has a circular shape having an opening in a partition 47 formed by a seal partition 46-2 and a partition 46-3. The heat generating part 48 is arranged at the center of the circle. The distal end of the partition wall 46-3 forming the opening of the circular partition 47 has a mountain-shaped flat cross section.
The opening 7 has a divergent shape to facilitate the inflow of ink.

The pressure reservoir partitions 46-4a or 46-4b are alternately arranged at positions facing the openings. The pressure reservoir partition wall 46-4a having a substantially square cross section covers the entire surface of the common electrode 49 so as to straddle the rectangular removal portion hole 51a in the short direction, and directs one side of the rectangle toward the heat generating portion 48. It is erected. Then, as shown in FIG. 4B, the pressure reservoir partition 46-4a has its tip not in contact with the back surface of the orifice plate 52, and
A predetermined gap 53 is formed between the leading end of-4a and the back surface of the orifice plate 52.

The other isosceles triangular pressure reservoir partition wall 46-4b having a long flat cross section is provided on the rectangular removing portion hole 51b longer than the removing portion hole 51a so that the base of the isosceles triangle forms the heat generating portion 48. It stands up to the direction. The pressure reservoir partition wall 46-4b is disposed so that a portion on the bottom side from the center of the isosceles triangle covers the removing portion hole 51b in the short direction, and a vertex side of the isosceles from the center defines the removing portion hole 51b. It is arranged so as to cover it.

Each of the pressure storage partition walls 46-4a and 46-4b is in close contact with the passivation film 55 on the surface of the substrate 54 exposed in the removal hole 51a or 51b. In addition, despite being disposed in the region where the common electrode 49, which is an inert metal film electrode, is disposed, the adhesion to the substrate surface is strong, and there is no risk of dropping or collapse.

A triangular pressure reservoir partition 46-4b, into which ink can easily flow, has its tip abutting on the back surface of the orifice plate 52, whereas a rectangular pressure reservoir partition having a somewhat poor ink inflow property. 46-4a compensates for the slightly inferior ink inflow by the gap 53 formed between the tip end and the back surface of the orifice plate 52, so that the ink inflow characteristics to all the partitions 47 are balanced. I have.

The length of one side of the pressure storage partition 46-4a facing the rectangular partition 47 is determined by the length of one side of the pressure storage partition 46-4a.
-4b has the same length as the bottom side of the partition wall 47 facing the partition portion 47, so that the pressure storage characteristics of the two pressure storage partitions 46-4a and 46-4b are the same. Therefore, the ejection characteristics of the ink ejected from the ink ejection nozzles 56 of the partitioning section 47 facing the pressure storage partitions 46-4a and 46-4b are also balanced.

The alternately arranged triangular pressure reservoir partition walls 46-4b have their isosceles apexes extending long and abutting against the back surface of the orifice plate 52, so that various stresses cause the interior thereof to be internally formed. It also serves as a support for supporting the orifice plate 52 from the back surface, which tends to bend and obstruct the ink flow path.

It should be noted that the pressure reservoir partition wall 46-4b may not be formed as an elongated isosceles triangle, but may be formed as an equilateral triangle as shown in FIG. In this case as well, if the electrode portion corresponding to the upright surface of the support is removed to form a removed portion hole, there is no danger of dropping or collapsing even with a support having a small upright area. It is advisable to form a small number of struts that are not large enough at appropriate locations.

In the above embodiment, the projection as a pressure reservoir partition is provided directly on the passivation film of the insulating substrate. However, the present invention is not limited to this, and the projection is provided below the electrode film at the position where the projection is provided. When a heating resistor film is present, the heating resistor film may be erected directly on the heating resistor film if the adhesion between the heating resistor film and the projection is good. In this case, if the adhesiveness between the heating resistor film and the projection is poor, a removed portion hole may be formed in the heating resistor, and the projection may be directly erected on the insulating substrate thereunder.

[0065]

As described above in detail, according to the present invention, a portion of the electrode corresponding to the standing surface of the pressure reservoir partition is partially or entirely removed to form a removed portion hole, and the removed portion hole is formed. Since the pressure reservoir partition is erected so as to directly contact the passive film on the substrate surface exposed to the substrate, the adhesion of the pressure reservoir partition to the substrate surface can be made extremely strong, and
It is possible to provide a highly reliable print head by eliminating the problem of missing or collapsing of the pressure reservoir partition in the print head manufacturing process or the like.

In addition, since the problem of the dropout or collapse of the pressure storage partition is solved, the pressure storage partition can be formed small. The arrangement interval can be made closer, and therefore, the resolution of the print head can be enhanced.

Similarly, by eliminating the problem of dropping or collapsing of the pressure reservoir partition wall, the pressure reservoir partition wall can be formed to protrude into the common flow path so as not to be obstructed. The orifice plate, which tends to bend inside, can be supported from the back surface.

[Brief description of the drawings]

FIG. 1A is a schematic plan view showing a state in an initial stage of a series of manufacturing processes of an inkjet printer head according to an embodiment, FIG. 1B is an enlarged view showing a part of the state, c) is a cross-sectional view taken along the line CC 'of (b), and (d) is a sectional view of D of (b).
It is -D 'sectional drawing.

2 (a) is a schematic plan view schematically showing a state in an intermediate stage of a series of manufacturing processes, FIG. 2 (b) is an enlarged view of a part thereof, and FIG. EE 'cross-sectional view of FIG.
It is FF 'sectional drawing of (b).

FIG. 3A is a schematic plan view schematically showing a state in a final stage of a series of manufacturing processes, FIG. 3B is a partially enlarged view showing the state in detail, and FIG. GG 'cross-sectional view of FIG.
It is HH 'sectional drawing of (b).

FIG. 4A is a diagram showing a state in which four mono-color print heads are arranged to form a full-color print head, and FIG. 4B is a diagram showing a state in which steps up to step 4 have been completed for the sake of easy understanding of the structure. It is.

5A is a view showing a cross section of a sample for measuring the adhesion strength, FIG. 5B is a view showing a state where the adhesion strength is strong, and FIG. 5C is a view showing a state where the adhesion strength is weak.

6 (a) to 6 (f) are diagrams showing the relationship between the shape of the pressure reservoir partition wall and the removed portion hole of the underlying electrode metal film, respectively.

7A is a plan view showing a configuration in which pressure reservoir partitions having different shapes are mixed in the same print head, and FIG.
It is a J 'sectional arrow view.

8 (a) is a plan view schematically showing a schematic configuration of a conventional thermal ink jet head, and FIG. 8 (b) is a plan view of FIG.
It is A 'sectional arrow view.

FIGS. 9A to 9D are diagrams showing an operation state when a conventional thermal inkjet head is driven to generate heat.

10A is a plan view schematically showing an improved configuration of a conventional thermal ink jet head, and FIG. 10B is a plan view of FIG.
FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermal inkjet head 2 Chip board 3 Heating resistor thin film 4 Heating part 5 Individual wiring electrode 6 Power supply common electrode 7 Partition 7a Seal partition 7b Partition partition 8 Orifice plate 9 Ink ejection nozzle 10 Ink flow path 11, 11a Ink 11b Ink drop 12 , 12a, 12b Membrane air bubble 13 Partition wall of pressure reservoir 20 Chip substrate 21 Common electrode 21-1 Wiring part to heating part 22 Common electrode power supply terminal 23 Individual wiring electrode 24 Heating resistor film 25 Heating part 26 Drive circuit 27 Drive Circuit terminal 28 Removal part hole 29 (29a, 29b, 29c, 29d) Common ink supply path 30 Ink supply hole 31 Partition 31-1 Seal partition 31-2 Seal partition 31-3 Partition partition 31-4, 31-4b, 31-4c, 31-4d, 31
-4e, 31-4f Pressure reservoir partition 32 Partition 33 Orifice plate 34 Ink flow path 35 Ink ejection nozzle 36 (36a, 36b, 36c, 36d) Mono color print head 38 Full color print head 41 Silicon wafer substrate 42 Base surface layer film 43 Partition wall material 44 Orifice plate material film 45 Print head 46-2 Seal partition wall 46-3 Partition partition wall 46-4a, 46-4b Pressure storage partition wall 47 Partition section 48 Heat generation section 49 Common electrode 51a, 51b Removal section hole 52 Orifice plate 53 Gap 54 Substrate 55 Passive film 56 Ink ejection nozzle

Claims (7)

[Claims] A plurality of discharge nozzles for discharging a liquid under pressure in a predetermined direction; and at least one opening formed on an insulating substrate so as to communicate with the discharge nozzles. A plurality of individual liquid chambers to which the liquid is supplied from the openings, electrode films respectively arranged on the insulating substrate in the individual liquid chambers for applying a voltage, and energy converters connected to the electrode films An inkjet printer head comprising: a plurality of energy generating elements configured to generate pressure energy for discharging the liquid; and a common liquid chamber that relays the supply of the liquid to each of the individual liquid chambers. An ink jet device comprising: a projection provided in a liquid flow path formed between the common liquid chamber and each opening of the individual liquid chamber and provided directly on a lower layer of the electrode film. Tsu Topurinta head. 2. The ink jet printer head according to claim 1, wherein the lower layer of the electrode film is an insulating substrate having a passivation film adhered to a substrate surface. 3. The projection body is made of a polyimide resin,
The substrate is a silicon substrate, and the passivation film is SiO 2
3. The ink jet printer head according to claim 2, wherein: 4. The energy generating element is a heating element formed by laminating an electrode film on a heating resistor film, and a lower layer of the electrode film is a heating resistor film laminated on an insulating substrate. The ink jet printer head according to claim 1, wherein: 5. The electrode film is made of an inert metal, and the protrusion is in direct contact with a lower layer of the electrode film through a removal hole formed in the electrode film made of the inert metal. 5. The ink jet printer head according to claim 1, wherein the ink jet printer head is provided. 6. The ink jet printer head according to claim 5, wherein said inert metal is Au. 7. The ink jet printer head according to claim 1, wherein the protrusion has a tip formed in contact with the back surface of the orifice plate.