JPH05338177A - Ink jet head and production thereof - Google Patents

Abstract

PURPOSE:To provide an ink jet recording head having a structure making an air bubble easy to vent from an ink reservoir and good in the sealing of a channel substrate and an ink manifold. CONSTITUTION:An ink reservoir 10 has a shape expanding toward an ink manifold 13 and the angle theta formed by the bottom part and rear wall of the reservir 10 is 90 deg. or more. Therefore, no air bubble is generated on the rear wall of the ink reservoir. A fitting protruding part 17 is formed to an ink manifold 13 and fitted in the opening part of the ink reservoir 10 to be bonded to the inner wall of the opening part by a sealing material to perform alignment and bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head, and more particularly to an ink jet head characterized by an ink flow path structure and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a recording method suitable for high speed recording, there is an ink jet recording method. A recording head used in an ink jet recording system is usually configured by joining a heater substrate having a heating element and a channel substrate having a channel groove and an ink reservoir formed therein. It is known that the channel groove and the ink reservoir in the channel substrate are formed by anisotropic etching using a silicon substrate.

The channel substrate described in FIG. 1 of JP-A-2-265754 is a method of forming an ink reservoir and a channel groove by starting etching only from the same surface. With respect to the ink reservoir, by using a mask pattern having a large opening width, the ink reservoir is etched until it penetrates the back surface to form a trapezoidal cross section.

Regarding the channel substrate described in FIG. 8 of Japanese Patent Laid-Open No. 2-99334, regarding the ink reservoir,
Etching is started from both the front and back sides, and is formed by penetrating.

FIG. 5 shows a channel substrate formed by etching an ink reservoir and a channel groove only from the same surface of a silicon substrate as described in FIG. 1 of Japanese Patent Laid-Open No. 2-265754. It is sectional drawing of the used inkjet head. In the figure, 1 is a heater substrate, 2 is a heat generating part, 3 is a pit layer, 4 is a pit, 5 is a bypass pit, 6 is a channel substrate, 7 is a nozzle, 8 is a channel, 9 is a connecting groove, 10 is an ink reservoir, Reference numeral 11 is a connecting end portion, 12 is a heat sink, 13 is an ink manifold, 14 is a sealing material, 15 is an ink supply pipe, and 16 is a bubble.

The heater substrate 1 is made of Si wafer, ceramic, glass or the like, and the heat generating portion 2 is provided thereon. The heat generating portion 2 is composed of a heat generating resistor, an electrode, a protective layer and the like, and a pit layer 3 is formed thereon. The pit layer 3 is formed by patterning the pits 4 and the bypass pits 5 using a photosensitive resin or the like.

As the channel substrate 6, a silicon substrate having a (100) crystal plane on its surface is used, and a channel groove for forming the channel 8, a connecting groove 9 and an ink reservoir 10 are formed by anisotropic etching. The etched surface is a 54.7 ° (111) crystal plane, and the ink reservoir 10 is a through hole surrounded by this crystal plane. In the figure, R is the opening size of the ink reservoir 10 penetrating the back surface of the channel substrate, and L is the distance from the opening of the ink reservoir 10 to the opening of the nozzle 7.

The channel 8 and the ink reservoir 10 are connected to the bypass pit 5 via a communication groove 9. The angle θ between the bottom of the ink reservoir 10 and the rear wall is 54.
The angle is 7 °, which is an acute angle. Further, the opening size on the front surface side of the channel substrate at the bottom of the ink reservoir 10 is wider than the opening size R on the back surface side of the channel substrate 6. Due to the large opening size on the back side,
As described in Japanese Patent Laid-Open No. 265754, it is possible to easily supply ink to the channels, and the opening size on the front surface side is small.
A large distance L from the opening to the nozzle surface can be taken. A large distance L has an advantage that a connection sealing area between the ink manifold 13 and the channel substrate 6 can be sufficiently secured. In a normal inkjet head, the width L of the connection sealing region is 0.5 to 0.5 as the application amount of the sealing material 14.
About 1.0 mm was required.

Ink is supplied to the ink manifold 13 by an ink supply pipe 15 from an ink tank (not shown). The ink supplied to the ink manifold 13 is
It is supplied to the heat generating portion 2 and the channel 8 through the ink reservoir 10, the communication groove 9 and the bypass pit 5. When a current is passed through the heat generating portion 2 to generate heat instantaneously, film boiling occurs and bubbles grow along the inner wall of the pit. The ink in the channel 8 is ejected from the nozzle 7 by the pressure due to the rapid growth of the bubbles and adheres to the recording paper (not shown) for printing.

In the case of such a conventional ink jet head, when the ink is supplied from the ink reservoir 10 to the nozzle 7 side, the angle θ of the rear wall of the ink reservoir 10 opposite to the nozzle 7 is an acute angle. This portion became a pocket, the flow of ink did not occur, and the air mixed in the ink sometimes generated bubbles 16. When the bubbles 16 are generated, there are problems that the flow path resistance becomes large, the bubbles enter the channel 8 during the printing operation, the ink ejection becomes unstable, and the printing quality deteriorates.

When the ink ejection direction is downward,
Since the bubbles 16 are not discharged to the outside of the ink reservoir 10, the bubbles 16 collect at the corners of the rear wall, and the accumulated bubbles 1
When 6 grows and becomes large, the ink supply port may be blocked, and as a result, ink may not be ejected.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an ink jet recording head having a structure in which bubbles easily escape from the ink reservoir and the sealing between the channel substrate and the ink manifold is good. It is intended to provide.

[0013]

According to a first aspect of the present invention, an ink manifold and an ink reservoir are provided, ink is supplied to a channel through the ink manifold and the ink reservoir, and ink is ejected. In the ink jet head for performing recording by the recording, the ink reservoir has an angle θ formed by the bottom portion and the rear wall of 90 ° or more, and the ink manifold is provided with a fitting convex portion. The fitting convex portion is fitted in the opening of the ink reservoir.

According to a second aspect of the invention, there is provided the method of manufacturing an ink jet head according to the first aspect,
A first etching step of forming a groove that does not penetrate through by performing etching for forming an ink reservoir from the back surface of a silicon substrate having a (100) crystal plane on the surface using the first mask; There is a second etching step of performing etching from both the front and back surfaces of the silicon substrate using a mask until the ink reservoir becomes a through hole, and the second etching step is performed from the back surface of the first etching step. The ink reservoir is formed by continuing the etching for forming the ink reservoir and etching the channel groove from the surface and the communication groove adjacent to the channel groove and communicating with the ink reservoir. It is what

[0015]

According to the first aspect of the present invention, since the angle .theta. Formed by the bottom portion of the ink reservoir and the rear wall has an angle of 90.degree. The rest can be prevented. Further, the fitting convex portion is provided on the ink manifold, and the fitting convex portion is fitted into the ink reservoir opening, whereby the inner wall of the ink reservoir serves as both alignment and sealing.

According to the invention of claim 2, (10
0) Anisotropic etching is performed from the back surface using a silicon substrate having a crystal plane on the front surface to form an ink reservoir with the (111) crystal plane, thereby forming an angle θ between the bottom of the ink reservoir and the rear wall. Can be 125.3 °, which is an angle of 90 ° or more. Further, in the first etching step, the ink reservoir is not penetrated, and in the second etching step, the ink reservoir and the communication groove are simultaneously etched to penetrate the ink reservoir, so that the etching time can be shortened as compared with the conventional case. At the same time, since the connecting end portion is also etched, a good connecting end portion shape can be formed.

[0017]

1 is a sectional view of an embodiment of the ink jet head of the present invention. In the figure, the same parts as those in FIG. Reference numeral 17 is a fitting convex portion. In this embodiment, the ink reservoir 10 has a shape that spreads toward the ink manifold 13, the angle θ between the bottom and the rear wall is 125.3 °, and bubbles are generated on the rear wall of the ink reservoir 10. It is also suitable for an inkjet head in which the ink ejection direction is downward.

However, the opening size R of the ink reservoir 10
Becomes larger, and thus L becomes smaller. As in the conventional example described with reference to FIG. 5, the width of the connection sealing region cannot be sufficiently set, and therefore the ink manifold can no longer be adhesively sealed to the region L. Therefore, the fitting protrusion 17 is formed on the ink manifold 13,
This is fitted in the opening portion of the ink reservoir 10 and joined to the inner wall of the opening portion by using the sealing material 14, so that the alignment and the joining are performed.

FIG. 2 is a plan view of the channel substrate. This figure is illustrated from the surface (the surface where the channel groove is formed), and is a case where a large number of chips are taken from one substrate. In the figure, 8 is a channel, 10 is an ink reservoir, and 11 is a connecting end. Also, the dimension R shown by the broken line
Is the opening size of the ink reservoir formed on the back surface of the channel substrate. The alternate long and short dash line 18 indicates the cutting position, and L is the distance between the nozzle surface and the ink reservoir opening end after cutting.

An adhesive is applied to the surface of this channel substrate, and after alignment bonding with the heater substrate, the position of the line 18 is cut to separate it into individual chips. The cut chip is, as shown in FIG. 1, a heat sink 12 made of Al.
Use silver epoxy or the like to adhere to. Ink manifold 13
The silicone sealing material 14 is applied in advance to the corners of the fitting convex portion 17 of
Is fitted into the ink reservoir 10 for alignment and joining. Rubber packing may be used as the sealing material 14.

FIG. 3 is a schematic view showing a method of manufacturing a channel substrate in the ink jet head of the embodiment described in FIG. In the figure, 6 is a channel substrate, 8 is a channel,
9 is a connecting groove, 10 is an ink reservoir, 11 is a connecting end,
Reference numeral 19 is a SiO ₂ film, 20 is a Si ₃ N ₄ film, 21 is an ink reservoir opening, 22 is a channel opening, and 23 is a connecting groove opening. First, an etching mask is manufactured. As shown in FIG. 3A, a silicon wafer having (100) on its surface is used as a channel substrate 6, and on both sides thereof, a Si ₃ N ₄ film 20 as a first etching mask and a second etching mask are formed. A SiO ₂ film 19 is formed and patterned. On the back surface of the channel substrate 6 (upper part of the drawing), an ink reservoir opening 21 for etching the ink reservoir is formed in both the Si ₃ N ₄ film 20 and the SiO ₂ film 19. On the surface of the channel substrate, a channel opening 22 and a connecting groove opening 23 for etching the channel groove and the communication groove are formed only in the SiO ₂ film 19.

The channel substrate 6 manufactured as described above is
The first etching is performed using the first etching mask. This etching is performed for 4 hours using a heated KOH aqueous solution, and as shown in FIG. 3B, the ink reservoir 10 is formed so as to form a groove that does not penetrate.
The thickness S that is not etched is, for example, approximately the same as the depth D of the completed communication groove shown in FIG. In the case of this embodiment, the thickness is 50 μm.

After completion of the first etching, the Si ₃ N ₄ film 20 used as an etching mask is entirely removed with heated phosphoric acid. This state is shown in FIG.

Next, Si as the second etching mask
A _second etching is performed using O ₂ film heat 19. This etching is performed from both sides with heated KOH aqueous solution.
If the etching is performed for 25 minutes to a depth of 25 μm,
As shown in (D), the ink reservoir 10 partially penetrates, and the ink reservoir 10 and the communication groove 9 are connected. At the same time, the channel 8 is formed.

Further, etching is performed from both sides for 10 minutes continuously, and a total of 20 minutes is etched.
As shown in (E), the ink reservoir 10 completely penetrates to the back surface. The connecting end 11 is etched at the same time so that a sharp edge of 54.7 ° is rounded to form a shape suitable for the ink flow path.

After completion of the second etching, the SiO ₂ film 19 is entirely removed by using hydrofluoric acid. This state is shown in Figure 3.
(F).

A process of joining the channel substrate 6 manufactured by the above process and a heater substrate (not shown), cutting into individual chips and attaching them to a heat sink, and inserting an ink manifold having fitting protrusions, etc. After that, the head is assembled.

In the above-mentioned manufacturing method, this ink reservoir is manufactured by double-sided etching, but the ink reservoir 1
0 and the connecting end portion 11 of the communicating groove 9 are neither the (111) crystal face nor the (100) crystal face, and the etching proceeds faster than the (100) crystal face. Therefore, the etching time after the connection, that is, FIG. It is desirable that the etching time described in () is as short as possible, and in this embodiment, the etching time of the connecting end portion 11 was set to a short time of 10 minutes. As a result, a good shape was obtained, but if etching was performed for a long time, as shown in FIG. 4, the etching progressed until it became stable at the closed (111) crystal face, resulting in an unfavorable shape. So be careful.

Further, if the conventional method of penetrating the ink reservoir 10 by the first etching and forming the communicating groove 9 by the second etching is adopted, the connecting end is formed only for the time for etching the depth of the communicating groove 9. The part 11 is also etched. However, as in this embodiment, the ink reservoir is not penetrated by the first etching, and the same depth as the depth of the communication groove 9 is left, and then both sides are etched simultaneously, so that the depth of the communication groove 9 is half. The ink reservoir and the communication groove 9 are not penetrated until they are etched. Therefore, the time for etching the connecting end 11 is
It is half that of the conventional one, and a good connecting end shape can be obtained.

[0030]

As is apparent from the above description, according to the present invention, the angle between the bottom of the ink reservoir and the rear wall is 90 ° or more, so that the flow of ink is smooth and air bubbles are generated in the ink reservoir. No longer occurs. Also,
Since the ink manifold having the fitting convex portion is fitted into the reservoir wall to perform the alignment sealing, it is not necessary to take a large sealing area for connecting the ink manifold and the channel substrate, and the ink reservoir bottom portion and the rear wall are The inkjet head can be manufactured even with the structure in which the angle formed by the angle is 90 ° or more, and the size can be made smaller than in the past.

Further, since the manufacturing method for shortening the etching time of the connecting groove portion between the ink reservoir and the communication groove is adopted, there is an effect that a good flow path structure can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an inkjet head of the present invention.

2 is a plan view of the channel substrate of FIG. 1. FIG.

FIG. 3 is a schematic diagram showing a method of manufacturing a channel substrate in the inkjet head of FIG.

FIG. 4 is an explanatory diagram of long-time etching.

FIG. 5 is a cross-sectional view of an example of a conventional inkjet head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 heater substrate, 2 heat generating part, 3 pit layer, 4 pit, 5 bypass pit, 6 channel substrate, 7 nozzle, 8 channel, 9 connecting groove, 10 ink reservoir, 11 connecting end part, 12 heat sink, 13 ink manifold, 14 Sealing material, 15 ink supply pipe, 17 fitting convex portion, 19 SiO ₂ film, 20
Si ₃ N ₄ film, 21 ink reservoir opening, 22 channel opening, 23 connecting groove opening.

Claims (2)

[Claims] 1. An ink jet head having an ink manifold and an ink reservoir, supplying ink to the channel through the ink manifold and the ink reservoir, and ejecting the ink for recording, the ink reservoir having a bottom portion and a rear wall. Has an angle θ of 90 ° or more, and the ink manifold is provided with a fitting convex portion, and the fitting convex portion is fitted in the opening of the ink reservoir. Inkjet head characterized by. 2. The method of manufacturing an ink jet head according to claim 1, wherein the first mask is used (100).
A first etching step of performing etching for forming an ink reservoir from the back surface of a silicon substrate having a crystal surface on the front surface to form a groove that does not penetrate, and both sides of the silicon substrate using a second mask. To etching from the ink reservoir to the through hole
And the second etching step comprises:
By continuing the etching for forming the ink reservoir of the first etching step from the back surface and performing the etching of the channel groove and the communication groove adjacent to the channel groove and communicating with the ink reservoir from the front surface. A method for manufacturing an inkjet head, wherein an ink reservoir is formed.