JP4656641B2 - Recording head and recording apparatus - Google Patents

Description

  The present invention relates to a recording head and a recording apparatus, and more particularly, to a joining structure of a substrate on which an ink supply port is formed and a flow path forming member on which an ejection port is formed in an inkjet recording head.

  There are various recording methods for recording devices such as printers. Among them, the inkjet recording method is a low-noise non-impact recording method, and is capable of high-density and high-speed recording operations. ing.

  As a structure of an ink jet recording head, a structure including a substrate made of silicon or the like and a flow path component made of resin is well known. A plurality of discharge ports and a plurality of flow channels (ink chambers) for guiding ink to the respective discharge ports are formed in the flow path component member. An ink discharge pressure generating element that applies discharge pressure to the ink and an ink supply port that supplies ink to the ink chamber are formed on the substrate. The flow path component is formed on the substrate and fixed by adhesion.

  Conventionally, various proposals have been made on a method of manufacturing an ink jet recording head by forming a flow path component member on a substrate. Patent Document 1 discloses a basic method for manufacturing an ink jet recording head. According to this method, first, the flow path pattern is formed of a soluble resin on the substrate on which the ink discharge pressure generating element is formed. Next, a resin layer such as an epoxy resin is formed on the flow path pattern so as to cover the flow path pattern and cured. When the soluble resin is eluted after cutting the substrate, an ink chamber is formed. Patent Document 2 discloses that a cationic polymerization cured product of an aromatic epoxy compound is effective as a resin for a flow path component.

  In recent years, in order to improve paper selectivity and water resistance in the ink jet recording system, ink has been made to be weakly alkaline. However, it has been found that when weakly alkaline ink is used, it may be difficult to maintain the adhesion between the substrate and the flow path component member over a long period of time. As a countermeasure, Patent Document 3 discloses a technique in which an adhesion layer made of a polyetheramide resin is provided between the substrate and the flow path component, thereby improving the adhesion between the substrate and the flow path component. . In Patent Document 4, an adhesive layer is formed over a plane area wider than the joint surface between the flow path wall and the substrate, considering that the tip of the flow path wall is easily peeled from the substrate among the flow path components. However, a method for improving the adhesion is disclosed.

By the way, in recent years, in order to achieve both high-speed recording and high-definition recording on a recording medium, a large ink-discharge droplet is discharged in the case of high-speed recording, and a small ink-discharge liquid is used to obtain a high-definition recorded image. Inkjet recording heads that eject droplets are known. Such an ink jet recording head is provided with ink ejection openings of different sizes in the same chip. FIG. 7 shows a conceptual diagram of a conventional ink jet recording head in which ink discharge ports of different sizes are provided in the same chip. 4A is a plan sectional view showing a part near the flow path of the ink jet recording head, FIG. 4B is a schematic sectional view taken along the line bb, and FIG. A schematic cross-sectional view along the line cc is shown. A flow path forming member 108 made of resin is formed on the substrate 102 provided with the ink supply port 103. The flow path component 108 includes a flow path wall 110 and a ceiling portion 111, and ink chambers 112 a and 112 b independent from each other are formed by these. A large-diameter ejection port 114a or a small-diameter ejection port 114b is formed in the ceiling portion 111 of each ink chamber 112a, 112b. The ink chambers 112a and 112b communicate with the ink supply port 103 through openings 113a and 113b. The discharge ports 114 a and 114 b are formed at positions facing the ink discharge pressure generating elements 104 a and 104 b provided on the substrate 102. The sizes of the ink chambers 112a and 112b differ depending on the size of the ejection ports 114a and 114 (large diameter ejection port 114a or small diameter ejection port 114b). As a result, the widths of the openings 113a and 113b are also different. It becomes. A plurality of flow path walls 110 are provided according to the number of ink chambers 112a and 112b. An adhesion layer 115 that enhances the adhesion between the flow path component 108 and the substrate 102 is formed between the flow path component 108 and the substrate 102. The adhesion layer 115 is provided as a comb-shaped portion 115 a between the substrate 102 and the base portion of each flow path wall 110, and the adhesion force between the substrate 102 and each flow path wall 110 is enhanced.
JP 61-154947 A JP-A-3-184868 JP-A-11-348290 JP 2002-248771 A

  However, the conventional ink jet recording heads having different ink chamber sizes in the same chip have the following problems. That is, when an ink jet recording head is prepared by the method described in Patent Document 1, a resist material, which is a material for a flow path pattern, is usually dissolved in an organic solvent to form a liquid and then applied by a spin coat method. Since the adhesion layer is formed under the channel pattern, the channel pattern is formed so as to cover the adhesion layer. Since the comb-shaped portion of the adhesion layer is selectively provided at the base portion of the flow path wall that is particularly likely to be peeled off, the resist material dissolved in the organic solvent is applied to the surface with unevenness. As a result, the resist material dissolved in the organic solvent rises at the convex portions where the comb-like portions are present, and becomes low at other portions.

  Here, when the sizes of the ink chambers are different, that is, when the widths of the openings of the ink chambers are different, the intervals of the flow path walls that partition the ink chambers are also different accordingly, and the intervals of the comb-like portions of the adhesion layer are also different. It will be. For this reason, when the interval between the comb-shaped portions of the adhesion layer is different, the interval between the convex portions is also different, and the liquid surface shape of the resist material is changed. That is, the liquid level of the resist material is lowered (especially in the central part) where the interval between the comb-shaped parts is wide, and the liquid level of the resist material is maintained at a relatively high level in the narrow area. When the resist material is covered with the flow path component in this state, the flow path component is formed to a deeper position at a low liquid level, and the flow path component is only at a relatively shallow position at a high liquid level. Not formed. As a result, when the resist material is removed, the height of the ink chamber varies depending on the site (see FIG. 5A). When the heights of the ink chambers are different, the ink ejection performance varies. Also, if the ink chamber height is different, the thickness of the ceiling portion is also different, so that the nozzle length of the ejection port varies, and it becomes difficult to control the size of the droplet that ejects ink. These cause variations in printing performance and quality.

  The present invention has been made in view of the above-described problems of the prior art, targeting ink jet recording heads having different opening widths of ink chambers within the same chip. An object of the present invention is to provide an ink jet recording head capable of suppressing variations in the height of ink chambers and suppressing variations in ink ejection performance on the premise of the ink jet recording head having such a structure.

  The recording head of the present invention has a substrate having an ink supply port for supplying ink, a flow path wall, and a plurality of ink chambers formed along the ink supply port and partitioned from each other by the flow path wall, Each of the plurality of ink chambers includes an opening that opens to the ink supply port and a discharge port that discharges the ink, and a flow path component formed on the substrate, and a gap between the substrate and the flow path wall from the substrate. A plurality of comb-shaped portions are provided so as to protrude in the direction of the flow channel wall, and each of the comb-shaped portions has an adhesion layer that enhances the adhesion between the corresponding flow channel wall and the substrate. The width of the opening in the direction in which the ink supply port extends differs from each other in at least some of the ink chambers, and the width of the gap between the comb-shaped portions in the direction in which the ink supply port extends is substantially the same.

  The ink chamber is formed by applying a liquid resin on a substrate on which an adhesion layer including a comb-like portion is formed, forming a flow path component from the substrate, and removing the last applied resin. . When the resin is applied, the resin swells above the comb-shaped portion and is recessed in a catenary line shape above the gap portion. In the recording head of the present invention, the widths of the gaps between the comb-like parts are substantially the same, so the liquid level (indentation shape) above the gaps has the same shape in each gap. For this reason, even if the widths of the openings of the ink chambers are different from each other, the heights of the ink chambers are formed substantially the same, and variations in ink ejection performance are effectively suppressed.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. The present invention can be applied to all recording heads. Here, an ink jet recording head in which an electrothermal transducer is used as means for giving ejection energy to ink will be described as an example. The subject of the present invention includes not only the recording head but also a recording apparatus on which the recording head is mounted. However, since the configuration of the recording apparatus itself is the same as that of the conventional recording apparatus, detailed description thereof is omitted. To do.

(First embodiment)
FIG. 1 is a partially broken perspective view showing a recording element substrate of a recording head according to the first embodiment of the present invention. The recording element substrate 1 includes a silicon (Si) substrate 2 having a thickness of 0.5 to 1 mm, for example. In the vicinity of the center of the substrate 2, an ink supply port 3 having a long and thin rectangular planar shape is opened. On the substrate 2, a plurality of ink ejection pressure generating elements 4 are formed on both sides along the longitudinal direction of the ink supply port 3. The ink discharge pressure generating element 4 is an electrothermal conversion element made of TaN and is formed by a film forming technique. Electrode portions 12 that receive electrical signals that drive the ink discharge pressure generating elements 4 are arranged along the outer edges of the substrate 2. The electrode portion 12 is connected to the ink discharge pressure generating element 4 through electrical wiring (not shown) extending through the substrate 2. On the electrode part 12, an electrical connection pad 13 made of gold (Au) or the like for receiving an electrical signal is formed.

  FIG. 2 is a perspective view showing a part of the recording element substrate (illustration of flow path components described later is omitted). A silicon nitride (SiN) layer 6 that protects the ink discharge pressure generating element 4 and the electrode portion 12 is formed on the substrate 2 over almost the entire surface. A tantalum (Ta) layer 7 is formed thereon so as to cover the ink discharge pressure generating element 4. The Ta layer 7 is provided in order to prevent damage to the ink discharge pressure generating element 4 caused by electrical contact with ink or cavitation due to defoaming of ink bubbles. The Ta layer 7 is formed in a band shape along the arrangement direction of the ink discharge pressure generating elements 4 while sequentially covering the adjacent ink discharge pressure generating elements 4, and the band portions on both sides sandwiching the ink supply port 3 are opposite to each other. And are formed in a rectangular shape as a whole.

  FIG. 3 is a partial plan view and a partial cross-sectional view of the recording element substrate. FIG. 5A is a partial plan view of the recording element substrate, and the illustration of the ceiling portion is omitted. FIG. 4B is a cross-sectional view taken along the line bb in FIG. 4A, and FIG. 4C is a cross-sectional view taken along the line cc in FIG. On the substrate 2 on which the layers up to the Ta layer 7 are formed, a flow path constituting member 8 made of a cationic polymerization compound of an epoxy resin is formed. The flow path component 8 includes a flow path wall 10 and a ceiling portion 11 disposed thereon.

  A plurality of flow path walls 10 are formed in a comb shape along the ink supply port 3. On the substrate 2, a plurality of ink chambers 12 a and 12 b are formed that are partitioned by the flow path walls 10 and the ceiling portion 11. As will be described later, the inner chamber dimensions of the ink chamber 12a and the ink chamber 12b are different from each other. The ink chambers 12 a and 12 b on each side of the ink supply port 3 each form an ink chamber row 18.

  A large-diameter ejection port 14a or a small-diameter ejection port 14b for ejecting ink is selectively provided in the ceiling portion 11 of each ink chamber 12a, 12b to form an ejection port group 17 (see FIG. 1). . A single discharge amount of the large-diameter discharge port 14a is, for example, about 5 pl (picoliter), and the small-diameter discharge port 14b is, for example, about 2 pl. These discharge ports 14a and 14b are provided to face the corresponding ink discharge pressure generating elements 4a and 4b. Ink is supplied from the ink supply port 3 and discharged from the discharge ports 14a and 14b by the pressure of bubbles generated by the heat generated by the ink discharge pressure generating elements 4a and 4b.

  The large-diameter ejection port 14a and the small-diameter ejection port 14b correspond to the ink chambers 12a and 12b, respectively. For this reason, the ink chamber 12a has a larger internal volume than the ink chamber 12b. Each of the ink chambers 12a and 12b includes openings 13a and 13b that open to the ink supply port 3, and the width A of the opening 13a in the extending direction 16 of the ink supply port 3 is larger than the width B of the opening 13b. In the present embodiment, the ink chambers 12 a and 12 b are alternately provided along the direction 16 in which the supply port 3 extends in each ink chamber row 18. That is, the openings 13 a and 13 b having different widths are alternately provided in the ink chamber row 18. However, the openings do not necessarily have to be arranged in this way, and the widths of the openings may be at least partially different from each other among the plurality of ink chambers 12 constituting the one ink chamber row 18. . A filter member made of a column may be provided in the vicinity of the openings 13a and 13b in order to capture foreign matter in the ink and adjust the flow resistance.

  An adhesion layer 15 made of a polyetheramide resin is formed between the flow path constituting member 8 and the SiN layer 6. The adhesion layer 15 includes a plurality of comb-shaped portions 15 a provided between the substrate 2 and the flow path wall 10 so as to protrude from the substrate 2 toward the flow path wall 10. The adhesion layer 15 has an effect of increasing the adhesion between the flow path component member 8 and the substrate 2. Each comb-shaped portion 15 a is sandwiched between each flow path wall 10 and the substrate 2, and acts so as to increase the adhesion between the flow path wall 10 and the substrate 2.

  The comb-like portion 15 a is completely covered with the flow path wall 10. This is because if the comb-like portion 15a protrudes into the ink chambers 12a and 12b, the flow of ink in the ink chambers 12a and 12b may be adversely affected.

  The widths of the gaps between the adjacent comb-like portions 15a in the extending direction 16 of the ink supply port 3 are substantially the same. That is, if the length of the protrusion from the comb-shaped portion 15a of the flow path wall 10 in the ink chamber 12a is C and the length of the protrusion from the comb-shaped portion 15a of the flow path wall 10 in the ink chamber 12b is D, the length in the ink chamber 12a The width (A + 2C) between the gaps between the comb-like parts 15a is substantially equal to the width (B + 2D) between the gaps between the comb-like parts in the ink chamber 12b. The effect of aligning the widths of the gaps between the comb-like parts in this way will be described in the following manufacturing method.

  FIG. 4 is a step diagram showing the manufacturing process of the ink jet recording head. In the following, a method for manufacturing the main part of the ink jet recording head will be described with reference to FIG.

  First, referring to FIG. 4A, an ink supply port mask 21 was formed on the lower surface of the substrate 2 made of a silicon wafer having a crystal axis <100>, leaving a portion to be the ink supply port 3. Next, the ink discharge pressure generating elements 4a and 4b and the electrode portion 12 (see FIG. 1) were formed on the upper surface of the substrate 2. An SiN layer 6 was formed thereon as a protective layer, and a Ta layer 7 was further formed thereon. The state of the ink jet recording head at this stage is also shown in FIG.

  Next, referring to FIG. 4B, a polyetheramide layer serving as the adhesion layer 15 was formed on the substrate 2 with a thickness of 2.0 μm. HIMAL1200 (trade name) manufactured by Hitachi Chemical Co., Ltd. was used for the polyetheramide layer, and this was coated on the substrate 2 with a spinner, and then heated at 100 ° C. for 30 minutes and then at 250 ° C. for 1 hour for baking. . Next, OFPR800 (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was formed in a predetermined pattern on the formed polyetheramide layer, and etching was performed by oxygen plasma ashing using this pattern as a mask. Thereafter, the OFPR pattern used as a mask was peeled off to form an adhesion layer 15. As described above, the comb-shaped portion 15a of the adhesion layer 15 was formed so that the widths of the gap portions were equal to each other.

  Next, referring to FIG. 4C, a positive resist ODUR (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was applied on the substrate 2 to a thickness of 13.5 μm. The resist was dissolved in an organic solvent and then applied by a spin coater using a spinner. Next, a mask was formed on the formed resist layer, and the resist material was etched. At this time, the resist layer was removed from the portion where the flow path wall 10 was formed so that the comb-shaped portion 15a of the adhesion layer 15 was completely exposed (not shown). Thus, the flow path pattern 22 having a predetermined shape was formed.

  Next, referring to FIG. 4 (d), a resin layer 23 made of an epoxy resin cationic polymerization compound was formed so as to cover the flow path pattern 22. The resin layer 23 is filled not only on the flow path pattern 22 but also in the space above the comb-shaped portion 15a, so that the flow path wall 10 is formed. Thereafter, the discharge ports 14a and 14b were opened by patterning.

  Next, referring to FIG. 4E, the ink supply port 3 was formed on the substrate 2 by Si anisotropic etching.

  Next, referring to FIG. 4F, the portion of the SiN layer 6 on the ink supply port 3 was removed, the flow path pattern 22 was dissolved and removed, and ink chambers 12a and 12b were formed. Then, in order to completely cure the epoxy resin layer serving as the flow path constituting member 8, heating was performed at 200 ° C. for 1 hour, and the main part of the ink jet recording head was completed.

  Here, the effect of aligning the width of the gap between the comb-like portions will be described. FIG. 5 is a schematic diagram showing a state when a resist material that is the basis of the flow path pattern 22 is applied by a spinner. The figure (a) shows the situation when the widths of the gaps between the comb-like parts are different in the prior art, and the figure (b) shows the same width of the gaps between the comb-like parts in the present invention. Each situation is shown. As shown in FIG. 5A, when the widths of the gaps between the comb-like parts 15a are different, the liquid surface 24 of the epoxy resin has a gap in the narrow part of the gaps (corresponding to the ink chamber 12b). There is no significant decrease even in the vicinity of the center (h1 in the figure). For this reason, a relatively high resin layer 23 is formed in the portion where the ink chamber 12b is formed. On the other hand, when the gap is wide (corresponding to the ink chamber 12a), the liquid level 24 of the epoxy resin is greatly lowered around the center of the gap (h2 in the figure). For this reason, a relatively low resin layer 23 is formed in the portion where the ink chamber 12a is formed. As a result, the heights of the ink chambers are different from each other (h3 and h4 in the figure). On the other hand, when the widths of the gaps between the comb-like parts 15a are uniform, as shown in FIG. 5B, the epoxy resin has the same liquid surface 24 shape in any gaps. In this case, the liquid level is equal to h5, and the heights of the ink chambers 12a and 12b are substantially equal to h6. Thus, by aligning the width of the gap between the comb-shaped portions, the ink chambers 12a and 12b can be formed at substantially the same height.

  Second Embodiment Subsequently, a recording head according to a second embodiment of the present invention will be described. FIG. 6 is a partial plan view and a partial sectional view of a recording head according to the second embodiment of the present invention. FIG. 5A is a partial plan view of the recording element substrate, and the illustration of the ceiling portion is omitted. FIG. 4B is a cross-sectional view taken along the line bb in FIG. 4A, and FIG. 4C is a cross-sectional view taken along the line cc in FIG.

  In the present embodiment, the first ink chamber row 18a of the recording head includes only the ink chamber 12a in which the large-diameter ejection port 14a is formed, and the second ink chamber row 18b has the small-diameter ejection port 14b. The ink chamber 12b alone. For this reason, the widths of the opening portions 13a and 13b of the ink chambers 12a and 12b are also the same in the ink chamber rows 18a and 18b, and are different in the ink chamber rows 18a and 18b. That is, the width E of the opening 13a in the direction 16 in which the ink supply port 3 extends is larger than the width F of the opening 13b. On the other hand, when the length of protrusion of the flow path wall 10 from the comb-shaped portion 15a in the ink chamber 12a is G and the length of protrusion of the flow path wall 10 from the comb-shaped portion 15a of the ink chamber 12b is H, the length of the ink chamber 12a The width (E + 2G) of the space between the comb-shaped portions 15a is substantially equal to the width (F + 2H) of the space between the comb-shaped portions in the ink chamber 12b. Other configurations are the same as those in the first embodiment. Also, the manufacturing method is exactly the same as in the first embodiment. The effect of this embodiment is also the same as that of the first embodiment. That is, since the width of the gap portion of the comb-like portion 15a is aligned not only in each of the ink chamber rows 18a and 18b but also between the ink chamber rows 18a and 18b, the heights of the ink chambers 12a and 12b are substantially equalized. Variations in discharge performance can be suppressed.

  As described above, according to the present invention, in an ink jet recording head having different ink chamber widths in the same chip, the height of the ink chamber can be made substantially constant regardless of the width of the ink chamber. Accordingly, it is possible to provide a higher quality ink jet recording head by suppressing variations in the ejection performance for ejecting ink.

1 is a partially cutaway perspective view showing a recording element substrate of a recording head according to a first embodiment of the present invention. FIG. 2 is a perspective view illustrating a part of a recording element substrate of the recording head illustrated in FIG. 1. FIG. 2 is a partial plan view and a partial cross-sectional view of a recording element substrate of the recording head shown in FIG. 1. FIG. 2 is a step diagram illustrating a manufacturing process of the recording head illustrated in FIG. 1. It is a schematic diagram which shows a state when apply | coating a resist material with a spinner. FIG. 6 is a partial plan view and a partial cross-sectional view of a recording element substrate of a recording head according to a second embodiment of the present invention. FIG. 6 is a conceptual diagram of a conventional ink jet recording head in which ink discharge ports of different sizes are provided in the same chip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording element board | substrate 2 Board | substrate 3 Ink supply port 4 Ink discharge pressure generating element 6 Adhesion layer 8 Flow path component 10 Channel wall 12a, 12b Ink chamber 13a, 13b Opening part 14a, 14b Ejection port 15 Adhesion layer 15a Comb

Claims (7)

A substrate having an ink supply port for supplying ink;
A channel wall and a plurality of ink chambers formed along the ink supply port and partitioned from each other by the channel wall, each of the plurality of ink chambers having an opening that opens to the ink supply port; A flow path component formed on the substrate, including a discharge port for discharging ink;
A plurality of comb-shaped portions provided between the substrate and the flow channel wall so as to protrude from the substrate toward the flow channel wall, each of the comb-shaped portions corresponding to the flow channel wall and the substrate; And an adhesion layer that enhances adhesion with
The width of the opening in the direction in which the ink supply port extends differs from each other in at least some of the ink chambers,
The recording head, wherein the gaps between the comb-like portions have substantially the same width in the direction in which the ink supply port extends.   2. The recording head according to claim 1, wherein at least a part of the width of the opening portion is different between the plurality of ink chambers constituting one ink chamber row. The flow path forming member forms at least two ink chamber rows;
2. The recording head according to claim 1, wherein the widths of the openings are substantially the same in the ink chamber rows and are different from one another in the ink chamber rows.   The recording head according to claim 1, wherein the comb-shaped portion is completely covered by the flow path wall.   The recording head according to claim 1, wherein the adhesion layer includes a polyetheramide resin.   The recording head according to claim 1, wherein the flow path constituent member includes a cationic polymerization compound of an epoxy resin.   A recording apparatus comprising the recording head according to claim 1.

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