JPH06183002A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To supply ink smoothly while suppressing crosstalk. CONSTITUTION:A nozzle 1, an individual reservoir 2, and a part 9 for coupling individual reservoirs 2 are formed in a channel wafer 6 by anisotropic etching. On the other hand, a heater corresponding to each nozzle is formed on a heater substrate 5 and a pit 4 is formed above the heater 3 while furthermore an individual bypass pit 8 corresponding to each nozzle is also formed. The heater wafer 5 and the channel wafer 6 are stuck each other to provide an ink jet recording head. Since an individual bypass pit 8 is formed, individual part of nozzle can be lengthened resulting in the reduction of crosstalk.

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 of a thermal ink jet recording device.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus has been developed in which an ink droplet is ejected from a nozzle by the pressure of a vapor bubble generated by heat generation of a heater for recording. The recording head used in this inkjet recording apparatus is composed of, for example, a channel substrate having a plurality of nozzles and a heater substrate having a plurality of heaters. FIG. 11 is a perspective view of a general inkjet recording head. In the figure, 1 is a nozzle, 3 is a heater, 4 is a pit, 5 is a heater wafer, 6 is a channel wafer, 10 is a thick resin layer, 22 is a common reservoir, 23 is a bubble, and 24 is an ink droplet. The channel wafer 6 is composed of, for example, a Si substrate, and has a plurality of nozzles 1 and a common reservoir 22.
Are formed by anisotropic etching. Further, in the heater wafer 5, the heater 3 is arranged on the Si substrate so as to correspond to the plurality of nozzles 1, and electrodes (not shown) for supplying a driving current to the heater 7, a protective film, etc. are formed. In addition, an insulating layer (not shown) and
The thick film resin layer 10 is laminated to form the heater wafer 5. The heater wafer 5 and the channel wafer 6 are bonded to each other to form a recording head. Ink is supplied from the opening on the channel wafer 6 and is supplied to each nozzle 1 via the common reservoir 22. Pit 4 on the heater 3
Are formed, the lateral growth of the bubbles 23 generated by the heat generation of the heater 3 is suppressed, and the bubbles are prevented from deviating from the nozzle 5 and the air is sucked in. The ink is ejected from the opening of the nozzle 1 by the pressure of the bubble 23 generated by the heat generation of the heater 3, and the ejected ink droplet 24 adheres to a recording medium (not shown) to perform recording.

In the conventional ink jet recording head as described above, the ink supply section and nozzles formed on the channel wafer are formed by anisotropic etching. The anisotropic etching is suitable for forming a rectangular portion and can be performed with high accuracy. Therefore, it is desirable to form the ink supply unit and the nozzle as separate rectangular portions. As an inkjet recording head adopting such a manufacturing method, for example, one described in JP-A-61-230954 is known.

FIG. 12 is an explanatory view of a channel wafer in a conventional ink jet recording head.
12A is a plan view and FIG. 12B is a sectional view. In the figure,
The same parts as those in FIG. 11 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 7 is an unetched portion, and 21 is a dicing connection groove. The inkjet recording head shown in FIG. 12 is an inkjet recording head of the same type as that described in JP-A-61-230954. A nozzle for ejecting ink to the Si wafer and a reservoir for supplying ink from the outside are formed by anisotropic etching so as to form separate rectangular regions. Further, in order to connect the reservoir and the nozzle to form the ink flow path, the dicing connection groove 21 is formed by dicing, and the unetched portion 7 between the reservoir and the nozzle is removed. As a result, a channel wafer is created.

In the recording head as described above, since the dicing connection groove is formed by dicing, the groove penetrates to the side surface of the head, and the filling and repair work is required on the side surface of the head. Further, since the dicing cannot be processed with high precision, the length of the nozzle cannot be formed with high precision. In order to eliminate such problems,
For example, JP-A-1-148560 and Japanese Patent Application No. 3-148
An ink jet recording head using a bypass pit as described in Japanese Patent No. 348525 is considered.

FIG. 13 is a sectional view of a conventional ink jet recording head using a bypass pit. 11 and 1
The same parts as those in 2 are given the same reference numerals and the description thereof will be omitted.
8 is a bypass pit. In the inkjet recording head shown in FIG. 13, while leaving the unetched portion 7,
The thick film resin layer 10 on the opposing heater substrate 5 is etched to form a common or individual bypass pit 8 for each nozzle to connect the reservoir and the nozzle.

As described above, in such an ink jet recording head, ink is ejected from the tip of the nozzle by the pressure of bubbles generated on the heater. The pressure of the bubbles at this time is also applied to the inside of the nozzle, and the pressure is transmitted from the common portion to other nozzles, affecting the nozzles in the vicinity. This is so-called crosstalk. This crosstalk is less likely to occur as the length of the nozzle portion is longer. Therefore, in order to suppress crosstalk, it is advantageous to use individual bypass pits for each nozzle because the nozzle portion becomes longer.

On the other hand, in the above-mentioned example, the common reservoir is 1
Only one is formed. However, when the recording head becomes large, the ink supply port of the reservoir also becomes large and the strength of the channel wafer decreases. As a method for solving this problem, for example, Japanese Patent Laid-Open No. 2-2356
As described in Japanese Patent Laid-Open No. 42-42, there has been considered a method of forming a reservoir by dividing it into a plurality of parts. When using a channel wafer with such divided reservoirs,
When the common bypass pit is used for each nozzle, the ink supplied from the other reservoirs is supplied through the common bypass pit, so that the shortage of the ink supply can be solved, but as described above, the crosstalk is prevented. The effect will decrease. The use of individual bypass pits for each nozzle enhances the effect of suppressing crosstalk, but since the nozzles that supply ink from one reservoir are fixed, some nozzles frequently eject ink. However, there is a problem that the amount of ink supplied from one reservoir is insufficient.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an ink jet recording head capable of smoothly supplying ink and suppressing crosstalk. To do.

[0010]

According to the present invention, there is provided an ink jet recording head comprising a channel substrate having a plurality of nozzles and a heater substrate having a plurality of heaters. The common liquid chamber part for connecting the liquid chambers is provided, and the heater substrate is provided with a plurality of recesses for connecting the common liquid chamber part and each nozzle.

[0011]

According to the present invention, since the channel substrate is provided with a plurality of liquid chambers to have strength and the liquid chambers are connected by the common liquid chamber, ink can be supplied between the liquid chambers. . Then, by connecting the common liquid chamber and each nozzle to each nozzle through a concave portion formed on the heater substrate, the length of the individual portion of the nozzle can be increased and crosstalk can be reduced. At this time, since the liquid chambers are connected by the common liquid chamber, there is no shortage of ink supply.

[0012]

1 is a schematic sectional view of an embodiment of the ink jet recording head of the present invention, and FIG. 2 is a plan view of a channel wafer used in the embodiment of the ink jet recording head of the present invention. 12, those parts that are the same as those corresponding parts in FIGS. 12 and 13 are designated by the same reference numerals, and a description thereof will be omitted. 2 is an individual reservoir, 9 is a connection reservoir part, and 11 is an individual reservoir partition. On the channel wafer 6, a nozzle 1, an individual reservoir 2, and a connecting reservoir portion 9 that connects the individual reservoir 2 are formed by anisotropic etching. The individual reservoir 2 is partitioned by an individual reservoir partition wall 11. Therefore, the openings serving as the ink supply ports of the individual reservoirs 2 are each partitioned, and the strength is higher than that of a conventional channel wafer forming one large opening. FIG. 2 shows an example in which six individual reservoirs 2 are provided. The number of individual reservoirs 2 may be set appropriately. Further, the individual reservoirs 2 are connected by the connection reservoir unit 9. Therefore, even if the supply of ink is insufficient in a certain individual reservoir, the ink supplied from another individual reservoir can be supplied to the portion having a shortage of ink via the connection reservoir unit 9. In this way, the connection reservoir allows ink to be stably supplied to the nozzles.

On the other hand, the heater substrate 5 is provided with the heater 3 corresponding to each nozzle, and the pit 4 is formed on the upper part of the heater 3, and further, the individual bypass is provided corresponding to each nozzle. Pit 8 is formed. These are formed by etching. The pits 4 are formed by patterning the thick resin layer 10 on the heater substrate 5 and a resin protective layer (not shown). The bypass pit 8 is formed by patterning only the thick resin layer 10. In the above channel wafer 6, the nozzle 1
The individual reservoir 2 and the connected reservoir portion 9 are separated by the unetched portion 7 and are not connected to each other.
Bypass pits 8 are formed corresponding to the respective nozzles in a portion facing to each other. Therefore, when assembled as a recording head, they are connected flow paths. The resin protective layer and the thick film resin layer 10 can be formed using a photosensitive polyimide (trade name Probimide: manufactured by Fuji Hunt Co., Ltd.) or the like.

The heater substrate 5 and the channel substrate 6 as shown in FIG. 2 are bonded together to form an ink jet recording head. The ink supplied from the opening of each individual reservoir 2 is supplied to the bypass pit 8 and the nozzle 1 corresponding to each nozzle via the connection reservoir 9.

In such an ink jet recording head, since the individual bypass pits 8 are used, the individual portions of each nozzle extend to the position of the connecting reservoir portion 9, so that crosstalk between nozzles can be reduced. it can.

3 to 7 are explanatory views of the manufacturing process of an embodiment of the ink jet recording head of the present invention. In the figure, the same parts as those in FIG. Reference numeral 12 is a Si ₃ N ₄ film, and 13 is a SiO ₂ film.

First, a SiO ₂ film 13 is formed on a silicon wafer 6 having a (100) crystal plane on its surface by thermal oxidation.
00Å is formed and a pattern is formed by a photolithography process so as to remove the nozzle, the individual reservoir, and the connection reservoir portion, and then the SiO ₂ film 13 is patterned by a dry etching method. Next, after forming the Si ₃ N ₄ film 12 by the CVD method, it is patterned so that only the individual reservoir is opened. The back surface of the substrate is unpatterned SiO
_{The two} films and the Si ₃ N ₄ film are left. This state is shown in FIG.

The two-layer mask pattern is shown in FIG.
In FIG. 8, the opening portion of the mask of the reservoir portion is shown. In the figure, the hatched portion is the Si ₃ N ₄ film 1
2 is the opened portion, and the hatched portion is the opened portion of the SiO ₂ film 13. This SiO ₂ film 13 serves as an etching mask in a second etching step described later, and is used for forming the connection reservoir portion 9 and for the adhesive portion above the individual reservoir partition wall 11 separating the individual reservoirs 2. To leave, as shown in Figure 8,
Created with a comb-shaped pattern. In addition, Si ₃ N ₄ film 1
2 is formed as a pattern in which a portion of the individual reservoir 2 is opened, as described above.

After forming the two patterns of etching masks as described above, the process moves to anisotropic etching.
First, as shown in FIG. 4, a first etching step for forming the individual reservoir 2 is performed with an aqueous potassium hydroxide solution heated to 90 ° C. using the Si ₃ N ₄ film 12 as an etching mask. At this time, the individual reservoirs 2 are separated from each other and are formed as through holes penetrating to the opposite side of the silicon wafer 6, and the opening on the opposite side of the silicon wafer serves as an ink supply port.

Next, as shown in FIG. 5, the Si ₃ N ₄ film 12 is removed with phosphoric acid heated to 180 ° C. And FIG.
As shown in FIG. 3, this time, a second etching step is performed in which the nozzle 1 and the connection reservoir portion 9 are formed with an aqueous potassium hydroxide solution heated to 90 ° C. using the SiO ₂ film 13 as an etching mask. At this time, since the portion of the individual reservoir 2 formed in the first etching step is also etched, a surface having a different angle from the surface formed when the flat surface is etched appears. However, since the individual reservoir 2 and the connection reservoir portion 9 are not required to have a very strict shape, it is safe to have such a surface.

Finally, the SiO ₂ film 13 is removed with hydrofluoric acid to complete the channel wafer 6 in which the nozzles 1, the individual reservoirs 2 and the connection reservoir portions 9 are formed, as shown in FIG. The completed channel wafer 6 is as shown in FIG.

The connecting reservoir portion 9 formed in the above-described manufacturing process does not have an opening exposed on the side surface after the recording head is formed, as compared with the case of using a conventional method such as dicing, so that a step of closing the same is unnecessary. is there.

FIG. 9 is a partial sectional view showing a concrete example of the ink jet recording head of the present invention. A recording head as shown in FIG. 9 was actually manufactured using the channel wafer manufactured by the above manufacturing process. In this figure, the cross section in the vicinity of the nozzle and the reservoir is schematically shown, and therefore the actual dimensions are different. The details of the opening of the mask pattern used to create the vicinity of the reservoir are as shown in FIG. The dimensions of each part shown in FIG. 8 are the openings of the Si ₃ N ₄ film 12 etched by the first etching, that is,
The length M1 of the individual reservoir 2 in the nozzle array direction is 1980.
μm, and the length M2 in the nozzle longitudinal direction is 1290 μm. In addition, SiO which is etched by the second etching
₂ The size of the opening of the film 13, that is, the portion of the individual reservoir 2 and the connection reservoir portion 9 is such that the individual reservoir portion is Si ₃
It is 20 μm larger than the opening of the N ₄ film 12 (the portion M3 in the figure), and the length L4 of the connecting reservoir portion 9 in the nozzle longitudinal direction is 198 μm. It is a region from the leftmost end to the rightmost end of the reservoir 2.

The dimension of the channel wafer 6 formed by using such a mask is that the length L1 of the ink supply port opened on the back surface of the channel wafer 6 by the first etching is 51.
2 μm. In the individual reservoir 2, the horizontal length L2 of the sloped surface that was etched in the first etching and not etched in the second etching is 311 μm. The angle is 54.7 ° during the first etching. The slope L etched by the first etching and further etched by the second etching has a horizontal length L3 of 151 μm and a vertical length L4 of 84 μm. The length L5 of the horizontal portion of the connection reservoir 9 is 78 μm,
The length L6 in the horizontal direction of the slope portion is 47 μm, and the length L7 in the vertical direction is 66 μm. The length L8 of the unetched portion 7 is 20 μm. The height L9 of the nozzle 1 formed with the reservoir is 35 μm.

The dimensions of the heater wafer used with the above channel wafer are as follows: the thickness L10 of the protective layer and the thick resin layer is 28 μm, and the bypass pit 9 from the nozzle opening.
The distance L13 to the end of the bypass pit is 302 μm, the length L11 of the bypass pit 9 is 144 μm, and the length L12 from the end of the unetched portion 7 on the connection reservoir 9 side to the side wall of the bypass pit 9 is 60 μm.

FIG. 10 is an enlarged view of the vicinity of the end of the nozzle array. Looking at the nozzle array direction of the inkjet recording head as described above, both ends of the connection reservoir 9 become slopes due to the second etching. Therefore, the connection reservoir 9
Insufficient ink is not supplied in the portion where the height of the ink is low. In order to eliminate this difference in ink supplyability, the nozzles in the area near the center where the height T of the connected reservoir 9 cannot be secured are dummy nozzles. Specifically, the height T of the connection reservoir 9 is (L4 + L7) in FIG.
It is 150 μm. In addition, Si by anisotropic etching
Has an etching angle θ of 54.7 °. When calculated from these values, the distance T2 at which the height T1 of the connection reservoir 9 cannot be secured is 122.4 μm. Since the arrangement interval of the nozzles is about 84.5 μm, it is sufficient to use two nozzles at each end as dummy nozzles. By using this dummy nozzle, it becomes possible to stably supply ink to other nozzles, and it is possible to improve the image quality defect at the head end portion.

[0027]

As is apparent from the above description, according to the present invention, the nozzles formed on the heater substrate are arranged so as to correspond to the individual bypass pits, and the nozzle and the reservoir are connected to each other. It is possible to increase the length of the individual parts of the above and reduce the crosstalk. Further, since the ink reservoir portion is divided into a plurality of parts, the channel substrate can be made stronger. At this time, since the individual reservoirs are connected by the connection reservoir, there is no shortage of ink supply.

[Brief description of drawings]

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

FIG. 2 is a plan view of a channel wafer used in an embodiment of the inkjet recording head of the present invention.

[Figure 3]

FIG. 7 is an explanatory diagram of a manufacturing process of an embodiment of the inkjet recording head of the present invention.

FIG. 8 is an explanatory diagram of an opening portion of a mask of a reservoir portion.

FIG. 9 is a partial cross-sectional view showing a specific example of the inkjet recording head of the present invention.

FIG. 10 is an enlarged view of the vicinity of an end of the nozzle array.

FIG. 11 is a perspective view of a general inkjet recording head.

FIG. 12 is an explanatory diagram of a channel wafer in a conventional inkjet recording head.

FIG. 13 is a cross-sectional view of a conventional inkjet recording head using a bypass pit.

[Explanation of symbols]

1 Nozzle, 2 Individual Reservoir, 3 Heater, 4 Pit, 5 Heater Wafer, 6 Channel Wafer, 7 Unetched Part, 8 Bypass Pit, 9 Connected Reservoir Part, 10 Thick Film Resin Layer, 11 Individual Reservoir Partition Wall, 12
Si ₃ N ₄ film, 13 SiO ₂ film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Saito 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Masahiko Fujii 2274, Hongo Ebina City, Kanagawa Prefecture (72) In Fuji Xerox Co., Ltd. (72) Inventor Naoki Morita 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Yoshihiko Fujimura 2274 Hongo Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Yukihisa Koizumi 2274 Hongo Ebina City, Kanagawa Prefecture Address: Fuji Xerox Co., Ltd. (72) Inventor, Masaki Kataoka, 2274 Hongo, Ebina, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor, Masa, 2274, Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox, Inc.

Claims (1)

[Claims] 1. A channel substrate having a plurality of nozzles,
In an ink jet recording head including a heater substrate having a plurality of heaters, a plurality of liquid chambers and a common liquid chamber portion that connects the plurality of liquid chambers are provided on the channel substrate, and the common liquid chamber portion is provided on the heater substrate. And an ink jet recording head having a plurality of recesses for connecting the respective nozzles.