JP3232915B2 - Inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet used in an ink jet recording apparatus for performing recording by ejecting ink.

[0002]

2. Description of the Related Art The structure of a conventionally known ink jet head is disclosed, for example, in JP-A-62-33648.
And Japanese Patent Application Laid-Open No. 1-148560. FIG. 9 is an explanatory diagram of the appearance of a general inkjet head. In the figure, 1 is the first substrate, 2 is the second substrate
, 3 is a thick resin layer, 4 is a nozzle, 5 is an ink inlet, 6 is wire bonding, and 7 is an ink droplet. On the first substrate 1, heating elements are arranged corresponding to the nozzles 4, and electrodes for supplying power to the respective heating elements are arranged. The heating element to which power is supplied by the electrodes heats the ink and generates bubbles in the ink. The supply of power to the electrodes is performed via wire bonding 6.
On the upper layer of the first substrate 1 on which the heating elements and the electrodes are arranged,
An insulating film, a protective layer, and the like are formed.
A thick resin layer 3 having a thickness of about 100 μm is formed. In the thick resin layer 3 above the heating element, a concave portion called a pit is formed, which defines a growth direction of bubbles generated by heat generation of the heating element. Further, for example, Japanese Patent Laid-Open No.
As described in JP-A-148560, a recess called a bypass pit may be formed to connect the ink inlet 5 and the ink flow path. A photosensitive resin is used for the thick resin layer 3, and pits are patterned using, for example, a photomask. In the second substrate 2, an ink flow path serving as a plurality of nozzles 4 is formed. Further, an ink inlet 5 serving as an ink inlet is provided.
The ink for recording enters through the ink inlet 5, passes through the internal ink flow path, and is ejected from the nozzles 4 as ink droplets 7.

FIG. 10 is an explanatory diagram of a method for manufacturing a general ink jet head. In the figure, 8 is a cutting line. As shown in FIG. 9, the inkjet head includes a first substrate 1 and a second substrate 2. As shown in FIG. 5, both the first substrate 1 and the second substrate 2 join the wafer of the first substrate 1 and the wafer of the second substrate 2 on which a large number of head elements are arranged with an adhesive. The individual inkjet heads are formed by cutting and separating along the line 8.

When two substrates are bonded by an adhesive, the adhesive is applied with a thickness of, for example, about 1 μm so as not to fill the inside of the nozzle with the adhesive, and a flow path shape as designed is formed. However, it is necessary to closely contact the two substrates without any gap so that ink leakage or the like does not occur.
However, in actuality, when two substrates are bonded together, poor adhesion occurs, which causes a reduction in the yield and life of the inkjet head.

One of the causes of the poor adhesion between the two substrates is the poor flatness of the photosensitive resin layer, which is a thick resin layer. Even if the photosensitive resin layer is applied flat, there is a phenomenon that when patterned and cured, the patterned and removed edges rise. The raised portion comes into contact with the second substrate, and a gap is generated between the other portion and the second substrate.

In order to avoid this swelling, for example, in Japanese Patent Application Laid-Open No. 4-357041, a concave portion is provided in a portion of the second substrate corresponding to a portion where the thick film resin layer swells. Adhesion is enhanced by avoiding contact with the second substrate. Further, for example, Japanese Patent Application Laid-Open
Japanese Patent No. 24203 describes that a large number of concave portions are provided in a wide portion of a bonding region of a second substrate, and a large number of raised portions of an adhesive are formed to increase a bonding area.

Although the adhesion between the two substrates has been improved by such a technique, it has not been perfect yet, and at times, poor adhesion of the nozzle surface as shown in FIGS. 11 and 12 has occurred. FIGS. 11 and 12 are explanatory diagrams of a state of poor adhesion between two substrates. FIG. 11 is a plan view, and FIG.
It is A 'sectional drawing. In the figure, the same parts as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted. 9a is a pit, 9b is a dummy pit (a pit provided in a dummy nozzle is referred to as a "dummy pit"), 10 is a bonding area, and 11 is a joining area.
Is an adhesive. In FIG. 11, most of the connection areas other than the connection area 10 at the end of the row of the pits 9a and 9b are in a poor connection state. At this time, in the nozzle portion, as shown in FIG. 12, the thick film resin layer 3 and the second substrate 2 are not joined, and the respective ink flow paths are not formed. In this state, it cannot be used as an ink jet head.

FIG. 13 is an explanatory view of the structure of a conventional ink jet head. FIG. 13 (A) is a plan view and FIG.
(B) is a sectional view taken along line AA. 9, FIG. 11, FIG.
The same parts as those in FIG. 12 are denoted by the same reference numerals, and description thereof will be omitted. 12 is an address electrode, 13 is a common electrode, 14 is a heating element, 15 is a glass layer, 16 is a protection layer, 17 is a heating element protection layer, 18 is a pit-to-pit wall, 19a and 19b are channel grooves, 20 is a projection, 21 is a lower part, and 22 is a dicing cutting area. However, in FIG. 13A, the channel groove is omitted and not shown.

As shown in FIG. 13B, the first substrate 1
A glass layer 15 having an insulating property is provided thereon. As described in FIG. 10, a plurality of ink jet heads are formed on a wafer and cut by dicing. To improve nozzle cutting quality, as shown in FIG. The structure does not expose the layer.

On the glass layer 15, heating elements 14 are arranged corresponding to nozzles for discharging ink.
Are connected to the address electrode 12 and the common electrode 13. In FIG. 13A, the lower side is the ink ejection direction.
The common electrode 13 is connected to the ink ejection side of the heating element 14, and the address electrode 12 is connected to the ink supply port side. Wiring to a drive circuit or the like for driving the heating element 14 is performed from the rear or side of the ink jet head.
It is wired upward in the figure.

A heating element protection layer 17 is formed on the heating element 14, and the address electrode 12, the common electrode 13, etc.
The protection layer 16 is formed on other portions. Further, a thick film resin layer 3 is formed thereon. The thick resin layer 3 above the heating element 8 is provided with pits 9a for defining the growth direction of bubbles generated by the heating of the heating element. At this time, since the ejection failure is likely to occur in the nozzle at the end, a dummy nozzle not intended for ejection is formed. In this example, the dummy nozzle is not provided with a heating element, but there is also one in which a heating element is provided. The dummy nozzle is provided with a corresponding dummy pit 9b.
However, as shown in FIG. 13B, the dummy pit 9b
Passing near the end of.

On the other hand, a channel groove 19 is formed in the second substrate 2.
a, 19b are formed. This channel groove also has a channel groove 19 corresponding to the dummy pit 9b not intended for ejection.
b is formed. An adhesive 11 is applied to the second substrate 2 and joined to the first substrate.

In such a conventional ink jet head, as shown in FIG.
Is formed on the surface near the end of the dummy pit 9b, and this portion is found to be the most convex. That is, the end of the dummy pit 9b, which is the end of the pit row, becomes convex because of the pattern edge, and further rises because the common electrode 13 overlaps. Since the pit-to-pit wall 18 is narrow, it is only slightly convex. Then, near the head end, a low portion 21 was formed. Since the thick resin layer 3 has such a shape, the protrusions 20 on the common electrode 13 formed at the end portions of the dummy pits 9b can be formed between the pits even if they are in close contact with and bonded to the second substrate 2. In some cases, the wall 18 and the lower portion 21 near the end of the head may have poor adhesion and bonding, the ink flow path was not formed, and the ink jet head could not be used.

Japanese Patent Application No. 5-303, which is a prior art of the present invention.
In the ink jet head described in No. 418, a convex portion is arranged at a portion other than the pattern end of the pit of the thick film resin layer to improve the flatness of the thick film resin layer, and the first substrate and the second substrate are formed.
To improve the state of close contact bonding of the substrate.

FIG. 14 is an explanatory view of the structure of the above-mentioned prior art ink jet head. FIG. 14 (A) is a plan view, and FIG. 14 (B) is a sectional view taken along line AA. In the figure, FIG.
The same reference numerals are given to the same portions as 3 and the description is omitted.
23 is a convex part. In this prior art, the common electrode 13 arranged in a portion having a large joining area at the head end is arranged at a distance W from the pattern end position of the dummy pit 9b. The distance W is, for example, 100 μm or more.

When the two substrates are joined in this way, the state shown in FIG. 14B is obtained. The protrusions 23 of the thick resin layer 3 corresponding to the common electrodes 13 are formed by the protrusions 20 at the end of the pit row.
The protrusions 20 are not particularly high, and the adhesion is improved by the protrusions 23.
Also, the portion of the pit-to-pit wall 18 can be satisfactorily joined by the adhesive 11.

However, even in this prior art,
The problem of the protrusion 20 remains. Since the protrusion 20 is formed at the end of the portion having a large joint area at the head end, it is inevitable that the protrusion 20 becomes higher than the upper part of the inter-pit wall 18. Therefore, there is a problem that a portion of the ink flow path near the end of the head may not be sufficiently bonded.

[0018]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been found to improve the adhesion between two substrates, improve the bonding quality and the production yield, and It is an object to provide a simple inkjet head.

[0019]

According to the present invention, a plurality of heating elements and an electrode for supplying power to the heating elements are provided, and a thick resin layer is formed on the heating element. The first pattern in which pits are formed in the thick resin layer
And a second substrate formed with a plurality of grooves serving as ink flow paths.
In the ink jet head manufactured by bonding the substrates, the width of the pit of the thick resin layer provided corresponding to the dummy nozzle at the end is formed to be narrower than the width of the other pits, and the common electrode is formed. Are arranged at least a predetermined distance away from the end of the pit of the thick resin layer provided corresponding to the dummy nozzle at the end.

[0020]

According to the present invention, the width of the outermost dummy pit is formed to be smaller than the width of the pit used for jetting, so that the outermost dummy pit is formed at the end of the thick film resin layer. The portion can escape to the channel groove portion, and poor adhesion between the substrates can be prevented. In addition, by increasing the distance from the end of the dummy pit at the extreme end to the common electrode by a predetermined distance or more, the protrusion caused by the common electrode can be separated from the protrusion at the end of the dummy pit. By improving the surface flatness, poor adhesion between the substrates can be further prevented.

[0021]

FIG. 1 is an explanatory view of a first embodiment of an ink jet head according to the present invention. FIG. 1 (A) is a plan view and FIG.
(B) is a sectional view taken along line AA. 13 and 14 in the figures.
The same parts as those described above are denoted by the same reference numerals and description thereof will be omitted. First, the first substrate 1 is created by using a manufacturing apparatus and a manufacturing method such as an LSI. The material of the first substrate 1 is silicon. On the first substrate 1, a glass layer 15 to be a heat storage layer or an insulating layer is formed. The glass layer 15 is formed, for example, by a method of thermally oxidizing the silicon substrate 1 to form a thermal oxide film, or by using NSG, BPSG, PSG, or the like by atmospheric CVD.
(Chemical vapor deposition), thermal CVD, low pressure CVD, plasma CVD, sputtering, etc. The heating element 1 is placed on the glass layer 15.
4, address electrode 12, common electrode 13, protective layer 16,
The heating element protection layer 17 and the like are laminated and patterned by, for example, various CVD methods or sputtering methods. The heating element 14 is made of, for example, a resistor such as polysilicon, hafnium boride, or tantalum nitride. The address electrode 12 and the common electrode 13 are made of, for example, aluminum or the like. The common electrode 13 is designed to flow a current of about 1 amp to drive the heating element 14 at the same time, and has a thickness of about 1 to 2 μm. Common electrode 13
As shown in FIG. 1A, in the portion where the joint area between the pattern of the dummy pit 9b and the head end is large, the distance W between the pattern end of the dummy pit 9b and the end of the pattern is 70 μm or more. The heating element protection layer 17 is formed by stacking a single layer or a plurality of layers of silicon oxide, silicon nitride, tantalum, or the like. The protective layer 16 is made of a glass layer 15
And the same material as described above. After these layers are laminated and patterned, a thick resin layer 3 is formed.
The photosensitive polyimide is spin-coated, photolithographically processed, and has a cured film thickness of 20 to 50 μm, for example, 30 μm.
m. The arrangement pitch of the pits in the arrangement direction was 85 μm. The dimensions of the pits are 120 μm in length when viewed in the ink ejection direction, and
The pit used for injection was 60 μm, and the dummy pit at the end was 30 μm.

Next, the second substrate 2 is made of silicon. A mask is formed on the second substrate 2 with a silicon oxide film, a nitride film, or the like. Then, selective etching depending on the crystal orientation in the KOH solution, that is, anisotropic etching (ODE) is performed to form the channel grooves 19a and 19b and other ink flow paths. Second channel groove formed
The adhesive 11 is transferred and applied to the substrate by, for example, a method described in JP-A-63-34152. As the adhesive 11, an epoxy-based and silane coupling agent or the like is used. The transfer coating thickness of the adhesive is about 1 μm. Thereafter, the first substrate 1 and the second substrate 2 are, for example,
The alignment is performed by using an infrared alignment method or the like as described in JP-A-61-230954, and the adhesive is cured by pressing and heating, and the adhesive is cured.

When the two substrates are joined in this way, the state shown in FIG. 1B is obtained. Dummy pit 9 at the end
By forming the width b to be smaller than the pit width used for injection, the position of the projection 20 can be placed below the channel groove 19b. In this manner, the protruding portion 20 having a large bulge can be escaped into the space of the channel groove 19b, and the bonding failure can be improved. Also, the dummy pit 9 at the extreme end
The distance W from the end of b to the common electrode 13 was 70 μm. The position of the common electrode 13 is changed to the dummy pit 9 at the end.
By separating from the end of “b”, the position of the protrusion 23 formed above the common electrode 13 is separated from the protrusion 20, thereby improving the flatness of the surface of the thick film resin layer 3, and Poor adhesion can be prevented.

FIG. 2 illustrates the surface flatness of the thick resin layer 3 when the distance W from the end of the outermost dummy pit 9b to the common electrode 13 is changed. Distance W
FIG. 6 conceptually shows the flatness of the surface of the thick film resin layer 3 when the thickness is 30 μm, 50 μm, and 70 μm;
In this figure, the thickness direction of the substrate is shown in an enlarged manner for easy understanding. The width of a normal pit was 60 μm, and the width of the dummy pit 9 b at the end was 30 μm.

FIG. 2A shows a case where W = 30 μm. Since the protrusion at the end of the dummy pit overlaps with the protrusion formed by the common electrode, the protrusion 24 is higher than the pit wall 18. The difference d in height between them was as large as 2.0 μm, and the adhesion was poor with respect to the adhesive thickness of about 1 μm.

FIG. 2B shows the case where W = 50 μm. Even in this case, it is inevitable that the protrusion at the end of the dummy pit and the protrusion due to the common electrode overlap, and d is 1.0 μm. For an adhesive thickness of about 1 μm, adhesion bonding failure often occurred.

FIG. 2C shows the case where W = 70 μm. In this case, since the protrusions 20 at the ends of the dummy pits are separated from the protrusions 23 formed by the common electrode, the difference d between these protrusions and the inter-pit wall 18 is only 0.2 μm, and the thickness of the adhesive is about 1 μm. On the other hand, it was possible to sufficiently adhere. As can be seen from FIG. 3 showing these results, W is 70 μm.
In the above case, the surface flatness of the thick resin layer was improved.

As described with reference to FIG. 1, it is sufficient for the dummy pit to have a flow passage width which is about half the width of a normal pit, and the function as a dummy nozzle can be ensured. It is possible to stably supply the ink to the nozzles, and it is possible to improve the poor image quality at the end of the head.

FIG. 4 is an explanatory view of a second embodiment of the ink jet head of the present invention. FIG. 4 (A) is a plan view, and FIG. 4 (B) is a sectional view taken along line AA. 1 and FIG.
3, parts similar to those in FIG. 14 are denoted by the same reference numerals, and description thereof is omitted. 9b1, 9b2 are dummy pits, 19b1, 1
9b2 is a channel groove. In this embodiment, the first point is that there are two dummy pits as shown at 9b1 and 9b2.
Is different from the embodiment. The width of the dummy pit 4b1 is
The width is the same as the width of the pit 9a corresponding to the nozzle for discharging ink. The width of the outermost dummy pit 9b2 is substantially half the width of the dummy pit 9b1. As shown in FIG. 4B, the bonding and adhesion of the two substrates are the same as in FIG. 1B, and the effect is the same as in the first embodiment described with reference to FIG.

FIG. 5 is an explanatory view of a third embodiment of the ink jet head of the present invention. FIG. 5 (A) is a plan view, and FIG. 5 (B) is a sectional view taken along line AA. In the figures, FIGS. 1, 4
13 and 14 are denoted by the same reference numerals and description thereof is omitted. In this embodiment, as shown in FIG. 5A, the shapes of the pits 9a and the dummy pits 9b1 and 9b2 of the thick resin layer 3 which define the growth direction of the generated bubbles are different from those of the second embodiment. I have. However, as shown in FIG. 5B, the bonding and adhesion of the two substrates are the same as in FIG. 1B, and the effect is the same as in the first embodiment described with reference to FIG.

FIG. 6 is an explanatory view of a fourth embodiment of the ink jet head of the present invention. FIG. 6 (A) is a plan view, and FIG. 6 (B) is a sectional view taken along line BB. In the figures, FIGS. 1, 4
13 and 14 are denoted by the same reference numerals and description thereof is omitted. 25a, 25b1, 25b are bypass pits. In this embodiment, individual bypass pits 25a, 25b1, 25b2 are provided for each nozzle in order to supply ink from the reservoir to the nozzles. In this case, in addition to the dummy pit 9b2 at the end, the width of the individual bypass pit 25b2 at the end is formed to be narrower than the width of the bypass pit 17a used for injection.
The cross-sectional view taken along the line AA in the pit portion is the same as that in FIG. 4B and is not shown, but the state of close contact between the substrates was good. Further, as shown in FIG. 6B, the cross section taken along the line BB of the bypass pit portion is also taken along the line A-B of the pit portion of the first embodiment.
As in the cross-sectional view along the line A, the state of adhesion between the substrates was good.

FIG. 7 is an explanatory view of a fifth embodiment of the ink jet head of the present invention. FIG. 7 (A) is a plan view, and FIG. 7 (B) is a sectional view taken along line BB. In the figures, FIGS. 1, 4
13 and 14 are denoted by the same reference numerals and description thereof is omitted. 25 is a bypass pit. In this embodiment, the bypass pit described in FIG. 6 is formed as a common bypass pit 25 for a plurality of nozzles. Ink is supplied from the reservoir through the bypass pit 25 to the nozzles whose ink flow paths are connected to the common bypass pit 25. In this embodiment, the end of the bypass pit 25 is located at the same position as the end of the outermost dummy pit 9b2 described with reference to FIG. The cross-sectional view taken along the line AA of the pit portion is the same as that of FIG. 4B, and although not shown, the state of close contact between the substrates was good. FIG.
As shown in (B), BB of the common bypass pit portion
In the line cross section, as in the AA cross section of the pit portion in the first embodiment, the state of close contact between the substrates was good.

FIG. 8 is an explanatory view of a sixth embodiment of the ink jet head of the present invention. FIG. 8 (A) is a plan view, and FIG. 8 (B) is a sectional view taken along line BB. In the figures, FIG. 1, FIG. 5,
6, 13, and 14 are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, as in the fourth embodiment, individual bypass pits 25a and 25b are provided for each nozzle.
Ink is supplied from the reservoir to the nozzles using 1, 25b2. Further, in this embodiment, similarly to the third embodiment, the shapes of the pits 9a, 9b1, 9b2 of the thick film resin layer 3 for defining the growth direction of the generated bubbles are different from the fourth embodiment. . Also in the case of this embodiment, the width of the individual bypass pit 17b2 at the end is formed to be narrower than the width of the bypass pit 17a used for injection. The cross-sectional view taken along the line AA of the pit portion is the same as that of FIG. 4B, and although not shown, the state of close contact between the substrates was good. Further, as shown in FIG.
As in the cross section taken along the line AA of the pit portion in the first embodiment, the state of close contact between the substrates was good also in the cross section taken along the line B.

[0034]

As apparent from the above description, according to the present invention, the width of the outermost dummy pit portion is formed smaller than the width of the pit used for injection, and the outermost dummy pit portion is formed. By increasing the distance from the pit end to the common electrode by a predetermined distance or more, the state of close bonding between the first substrate and the second substrate is improved, the production yield is improved, and the ink ejection characteristics are more stabilized. This has the effect.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of an ink jet head of the present invention.

FIG. 2 is a cross-sectional view illustrating the flatness of the surface of a thick resin layer when a distance W from an end of a dummy pit at the end to a common electrode is changed.

FIG. 3 is an explanatory diagram of the result of FIG. 2;

FIG. 4 is an explanatory diagram of a second embodiment of the ink jet head of the present invention.

FIG. 5 is an explanatory view of a third embodiment of the ink jet head of the present invention.

FIG. 6 is an explanatory diagram of a fourth embodiment of the ink jet head of the present invention.

FIG. 7 is an explanatory view of a fifth embodiment of the ink jet head of the present invention.

FIG. 8 is an explanatory diagram of a sixth embodiment of the ink jet head of the present invention.

FIG. 9 is an explanatory diagram of the appearance of a general inkjet head.

FIG. 10 is an explanatory diagram of a method for producing a general inkjet head.

FIG. 11 is a plan view showing a state of poor adhesion between two substrates.

FIG. 12 is a cross-sectional view showing a state of poor adhesion between two substrates.

FIG. 13 is an explanatory diagram of a structure of a conventional inkjet head.

FIG. 14 is an explanatory diagram of a structure of a prior art inkjet head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 2nd board | substrate, 3 ... thick film resin layer, 4
... nozzle, 5 ... ink inlet, 6 ... wire bonding, 7 ... ink drop, 8 ... cutting line, 9a ... pit, 9
b, 9b1, 9b2: dummy pit, 10: joining area,
11: adhesive, 12: address electrode, 13: common electrode,
14: heating element, 15: glass layer, 16: protective layer, 17
... heat-generating element protective layer, 18 ... pit wall, 19a, 19
b, 19b1, 19b2 ... channel groove, 20 ... convex part, 2
1 low part, 22 dicing cutting area, 23, 24 convex part, 25, 25a, 25b1, 25b ... bypass pit.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoshi Kotake 2274 Hongo, Fujina Rocks, Ebina-shi, Kanagawa Prefecture (72) Inventor Masaru Suzuki 2274 Hongo, Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/05

Claims (1)

(57) [Claims] A plurality of heating elements and electrodes for supplying power to the heating elements are provided, and a thick resin layer is formed thereon, and pits are formed in at least the thick resin layer above the heating elements. In the ink jet head manufactured by joining the formed first substrate and the second substrate in which a plurality of grooves serving as ink flow paths are formed, the thickness provided corresponding to the dummy nozzle at the outermost end is formed. The width of the pit of the film resin layer is formed narrower than the width of the other pits, and the common electrode is formed from the end of the pit of the thick film resin layer provided corresponding to the dummy nozzle at the end. An ink jet head, which is arranged at a predetermined distance or more.