JPH05131637A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To provide an ink jet recording head stabilized in the emitting direction of an ink droplet as compared with a conventional triangular nozzle by forming the orifice of a nozzle into a trapezoidal shape. CONSTITUTION:A thick insulating layer 3 is provided on a heater substrate 1 having a heating resistor 7 and a bypass pit 6 and a pit 8 are formed to the layer 3. A channel substrate 2 is formed from a silicon wafer by anisotropic etching to form an ink reservoir 5 and a channel part 9. Two substrates are bonded to be cut by a dicing saw. Since the cutting position of the substrates is set to the inclined part of the pattern end part of the channel part 9 as shown by the broken line in Fig (C), a nozzle whose orifice has a trapezoidal shape as shown by Fig A can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head, and more particularly to an ink jet recording head having a characteristic nozzle shape.

[0002]

2. Description of the Related Art Conventionally, as an ink jet recording head, as described in Japanese Patent Laid-Open No. 148560/1989, a heating resistor is heated to vaporize ink to generate bubbles, and the pressure of the bubbles is utilized. There is known a so-called thermal ink jet recording head which ejects ink by means of ink. 4A and 4B are explanatory views thereof, FIG. 4A is a front view seen from the nozzle surface, FIG. 4B is a sectional view taken along a vertical plane along the channel axis, and FIG. 4C is a channel substrate in a manufacturing process. 2D is a plan view of the heater substrate in the manufacturing process. In the figure, 1 is a heater substrate, 2 is a channel substrate, 3 is a thick film insulating layer, 4 is a nozzle, 5 is an ink reservoir, 6 is a bypass pit, 7 is a heating resistor, 8 is a pit, 9 is a channel portion, and 10 is a channel portion. Is an ink drop. The thick film insulating layer 3 is formed on the heater substrate 1 using photosensitive polyimide or the like, and then the bypass pits 6 and the pits 8 are provided by photolithography or the like. The pit 8 is patterned so as to open at the position of the heating resistor 7,
The bypass pit 6 includes the channel portion 9 and the ink reservoir 5.
Patterned at positions corresponding to the non-etched regions between. The pits 8 limit the growth area in the growth process when bubbles are generated so that the bubbles do not spread laterally and can be easily concentrated upward, and ink is effectively ejected, and at the same time from the ink ejection port. Is effective in preventing the inflow of air. Bypass pit 6 is
This is for forming a flow path that connects the ink reservoir 5 and the channel portion 9.

The channel substrate 2 is formed by forming a channel portion 9 having a triangular cross section on a Si wafer. In the manufacturing process of the channel substrate 2, anisotropic etching is performed on a Si wafer to form a channel portion 9 which will be an ink flow path. Channel substrate 2 manufactured in this way
Is adhered onto the heater substrate 1 having the thick film insulating layer 3 formed thereon, and is separated by dicing into a size used for each head to form a head portion. The cutting and separation by dicing are performed at the positions indicated by broken lines in FIGS. As can be seen from the figure (C), since the cutting position of the channel substrate is the position where the bottom of the groove is etched, the nozzle surface has a triangular shape as shown in the figure (A).

However, in the conventional head structure, the side opposite to the side of the corresponding thick film insulating layer at the bottom of the triangle is
Since it is a hypotenuse of a triangle and the apex is formed by two hypotenuses, there is a problem that the ink is attracted to the thick film insulating layer side and the ejection direction of the ink droplet is not stable.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems and provides an ink jet recording head in which the ejection direction of ink droplets is stable by making the opening shape of the nozzle trapezoidal. It is intended to be provided.

[0006]

According to the present invention, there is provided a first substrate having a pressure generating means and a second substrate having a channel portion and an ink reservoir formed by anisotropic etching of silicon.
In the ink jet recording head configured by joining with the substrate, the opening shape in the nozzle surface of the channel portion is formed in a trapezoidal shape.

A trapezoidal nozzle opening can be formed by cutting the terminal inclined portion of the channel portion formed by anisotropic etching. The channel part can be formed by two-step anisotropic etching to form a channel part having a trapezoidal cross section. The trapezoidal nozzle cross-sectional area of the ink ejection port may be smaller than the cross-sectional area of the triangular nozzle formed by anisotropic etching.

[0008]

According to the present invention, since the shape of the opening on the nozzle surface is trapezoidal, the opposite side is provided in parallel with the side of the thick film insulating layer, so that the ink retaining property is made uniform and the ink ejection direction is improved. Stabilization can be achieved.

[0009]

1A and 1B are explanatory views of a first embodiment of an ink jet recording head of the present invention. FIG. 1A is a front view seen from a nozzle surface, and FIG. 1B is a vertical surface along a channel axis. A cross-sectional view taken along line (C), a plan view of a channel substrate in the manufacturing process, and a (D) diagram of the heater substrate in the manufacturing process. In the figure, parts similar to those in FIG. 4 are designated by the same reference numerals, and description thereof will be omitted.

The heater substrate 1 has a heating resistor 7, and electrodes, a protective layer, and the like for energizing the heating resistor 7 are provided. The thick film insulating layer 3 is formed on the heater substrate using, for example, a photosensitive polyimide resin. The material is not limited to the polyimide resin, and other materials can be used as long as they can be patterned and are not corroded by ink. In this example, 300
The recording head of spi is formed, and the thickness of the thick film insulating layer 3 is set to 3
It was set to 0 μm. As shown in FIGS. 7B and 7D, the region other than the thick film insulating layer which is patterned is a bypass connecting the pit 8 in the region of the heating resistor 7 and the ink reservoir 5 and the channel 9. It is pit 6.

Next, the channel substrate 2 shown in FIG.
The manufacturing method of is explained. An Si ₃ N ₄ film is deposited on a Si wafer having a (100) crystal plane on its surface, and an etching mask is formed through a photolithography process and an etching process. The mask pattern has an opening in the region where the ink reservoir 5 and the channel portion 9 are formed. The back surface is entirely covered with a Si ₃ N ₄ film. In this way, Si
After patterning an etching mask on the wafer and etching with a heated KOH aqueous solution, a channel section 9 having a triangular cross section surrounded by {111} planes having an extremely slow etching rate and an ink reservoir 5 penetrating the wafer are formed. can do.

This etching method utilizes the fact that the etching rate varies depending on the crystal orientation, and is a method called anisotropic etching. By performing the orientation alignment of the crystal plane of the Si wafer with high precision, the finished size is obtained. You can make something with a very high accuracy.

These two types of substrates are formed as a large number of chips on a silicon wafer, and after the two substrates are bonded together, an alignment reference point (not shown) of the heater substrate is formed.
To cut with a dicing saw. Since the cutting position at the reference point is the inclined portion of the pattern end portion of the channel portion 9 as shown by the broken line in (C), a nozzle having a trapezoidal opening shape is produced as shown in (A). it can.

The advantage of the nozzle of this embodiment is that since the nozzle opening is provided with the opposite side parallel to the side of the thick film insulating layer, the ink holding property is improved and the ink is pulled toward the thick film insulating layer side and the ejection direction is not stable. This problem is less likely to occur. Moreover, since the cross-sectional area of the opening of the nozzle can be reduced, the flow velocity can be increased and the ejection direction can be further improved.

Further, in terms of manufacturing, since the nozzle surface can be formed by cutting the inclined portion at the end of the channel portion with a dicing saw, there is an advantage that a new head can be manufactured without increasing the number of manufacturing steps. ..

2A and 2B are explanatory views of a second embodiment of the ink jet recording head of the present invention. FIG. 2A is a front view seen from the nozzle surface, and FIG. 2B is a vertical surface along the channel axis. A sectional view taken, (C) is a plan view of the channel substrate in the manufacturing process, and (D) is a plan view of the heater substrate in the manufacturing process. In the figure, parts similar to those in FIG. 4 are designated by the same reference numerals, and description thereof will be omitted.

Although a heater substrate is shown in FIG. 3D, its manufacturing process is the same as that of the first embodiment, and therefore its explanation is omitted. FIG. 3C shows the channel substrate 2 having the channel portion 9 formed by anisotropic etching of silicon. The channel portion 9 has a trapezoidal sectional shape.

Next, a method of manufacturing the channel substrate 2 in the second embodiment will be described with reference to FIG. In the figure, 5 is an ink reservoir, 9 is a channel portion, 11 is a silicon substrate, 12
Is a SiO ₂ film, 13 is its opening pattern, and 14 is Si ₃
The N ₄ film, 15 is the opening pattern. By thermal oxidation on a silicon substrate 11 having a (100) crystal plane on its surface,
After the SiO ₂ film 12 is formed, patterning except for the channel portion 13 and the ink reservoir portion 15 is performed by a photolithography process as shown in FIG. 7A, and a first etching mask is formed by a dry etching method. Next, CV
A Si ₃ N ₄ film 14 is deposited by the D method, patterning is performed by a photolithography process so as to remove the ink reservoir portion 15, and a second etching mask is formed by a dry etching method. A plan view in which the etching mask is formed is (A), and the opening 13 of the SiO ₂ film 12 is
It is covered with the Si ₃ N ₄ film 14.

Thus, the SiO ₂ film 12 and the Si ₃ N ₄
Of the etching mask formed of the two layers of the film 14, first, the Si ₃ N ₄ film 14 is used to perform the first anisotropic etching with a heated KOH aqueous solution, and the ink reservoir 5
(B) is a state in which is formed. Next, after removing the Si ₃ N ₄ film 14 with heated phosphoric acid, a second anisotropic etching is performed with a heated KOH aqueous solution using the SiO ₂ film 12 as an etching mask to form the channel portion 9. Form. In this second anisotropic etching,
As shown in the figure (D), the etching of the channel portion 9 proceeds from left to right. That is, when the trapezoidal shape gradually changes with etching time and etching stops at the {111} plane, the nozzle portion 9 has a triangular shape as described in the first embodiment. In this embodiment, etching is stopped before forming a triangle, and a nozzle portion 9 having a trapezoidal cross section is produced. By controlling this trapezoidal shape by etching time, a trapezoidal nozzle having a desired size can be easily obtained. Finally, the remaining SiO ₂ film 12 is entirely removed with hydrofluoric acid.

Returning to FIG. 2, description will be made. The channel substrate obtained in FIG. 3 is formed as a large number of chips on a silicon wafer, and after bonding with a heater substrate manufactured corresponding to this, it is cut with a dicing saw at the alignment reference point of the heater substrate. To do. The cutting position at the reference point is
(C) As shown by the broken line in the figure, since the cross section located inside the pattern end of the channel portion 9 is a trapezoidal portion,
As shown in FIG. 3A, a nozzle having a trapezoidal opening can be manufactured.

The advantage of the nozzle of this embodiment is that since the opposite side is provided in parallel with the side of the thick film insulating layer, the ink holding property is increased and the ink is drawn by the thick film insulating layer and the ejection direction is not stable. In the case of the bottoms of the same size, the nozzle cross-sectional area can be made smaller than that of the conventional triangular nozzle, so that the flow velocity can be increased and the discharge direction can be further improved.

Further, from the viewpoint of production, a trapezoidal channel portion can be produced only by controlling the etching time, and this trapezoidal portion can be cut with a dicing saw to form a nozzle surface, so that the number of production steps is not increased. There is an advantage that a new head can be manufactured.

[0023]

As is apparent from the above description, according to the present invention, the opening of the nozzle surface is trapezoidal, and the opposite side is provided in parallel to the side of the thick film insulating layer, the holding property is improved, and the thick film insulating layer is formed. The phenomenon that the ejection directionality of the layer is not stable is unlikely to occur. Further, since the nozzle cross-sectional area can be reduced and the flow velocity can be increased, there is an effect that the ejection directionality can be further improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of an inkjet recording head of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the inkjet recording head of the present invention.

FIG. 3 is an explanatory diagram of a method of manufacturing the channel substrate 2 in the second embodiment.

FIG. 4 is an explanatory diagram of a conventional inkjet recording head.

[Explanation of symbols]

1 heater substrate, 2 channel substrate, 3 thick film insulating layer, 4 nozzles, 5 ink reservoir, 6 bypass pits, 7 heating resistor, 8 pits, 9 channels, 1
0 ink drop.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yutaka Mori 2274 Hongo, Ebina City, Ebina, Kanagawa Prefecture Fuji Zero Tsukus Co., Ltd.Ebina Business Office (72) Inventor Shinji Tabata, 2274 Hongo, Ebina City, Kanagawa Fuji Zero Tsuxu Ebina Business Co., Ltd. (72) Inventor Naoshi Otake 2274 Hongo, Ebina, Ebina, Kanagawa Prefecture Fuji Zero Tsux Co., Ltd.Ebina Business Office (72) Inventor, Hiroshi Ikeda 2274, Hongo, Ebina City, Kanagawa Fuji Zero Tsuxu Ebina Business Office (72) Inventor Jiro Minabe 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Zero Tux Co., Ltd.

Claims (1)

[Claims] 1. An ink jet recording head comprising a first substrate having a pressure generating means and a second substrate having a channel portion and an ink reservoir formed by anisotropic etching of silicon. An ink jet recording head, wherein an opening shape on a nozzle surface of a channel portion is formed in a trapezoid.