JP2007283549A - Inkjet recording head and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a decrease in printing quality caused by a difference in ink charging time by shortening a distance between delivering opening arrays when ink supplying ports are arranged zigzag. <P>SOLUTION: 1. In an inkjet head with a plurality of ink supplying port arrays arranged zigzag, the ink supplying ports are constituted so that wall faces inside of different ink supplying port arrays become parallel to each other. 2. The ink supplying ports of the inkjet head are formed by perpendicular anisotropic etching. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that discharges a desired liquid by applying energy to the liquid from the outside, and a method for manufacturing the ink jet recording head, and in particular, using kinetic energy generated by heating and foaming a liquid with thermal energy. The present invention relates to an inkjet recording head that ejects liquid and a method for manufacturing the inkjet recording head.

  The ink jet recording method disclosed in, for example, Japanese Patent Application Laid-Open No. 54-51837, which is open to this type of ink jet recording head, is a method of using other ink jets in that heat energy is applied to a liquid to obtain a driving force for wave droplet ejection. It has different characteristics from the recording method. That is, in the recording method disclosed in the above publication, the liquid subjected to the action of thermal energy is heated to generate bubbles, and droplets are discharged from the orifice at the tip of the recording head by the action force based on the generation of bubbles. It is characterized in that information is recorded by forming the droplets on the recording member. A recording head applied to this recording method generally includes an orifice provided for ejecting a liquid, and a heat acting portion that is a portion where heat energy for ejecting droplets communicated with the orifice acts on the liquid. A liquid discharge section having a liquid flow path having a liquid crystal structure as a part, a heating resistance layer as a heat conversion body that is a means for generating thermal energy, an upper protective layer that protects it from ink, and a lower layer for storing heat It has.

  In recent years, in order to realize high-definition image recording at a higher speed, there has been a demand for a wider print width and a higher arrangement density of orifices. 8-10 will be used for explanation.

  FIG. 8 is an external perspective view showing an example of a conventional ink jet recording head, FIG. 9 is a schematic perspective view schematically showing the cross section of the main part, and FIG. 10 is a schematic view schematically showing the top surface thereof. FIG.

  In this ink jet recording head, a heater 111 is provided on a silicon substrate 101 and nozzles are formed by a nozzle material 113. Ink is supplied from the back surface of the silicon substrate 101 through an ink supply port 110 formed as a hole penetrating the silicon substrate 101. By applying electric energy to the heater 111 to heat and foam the ink, the ink is ejected from the ejection port 102 and recording is performed. Application of electric energy to the heater 111 is performed by a transistor circuit in the driving element 103 provided on the silicon substrate 101 through the electric circuit board 107 and the flexible circuit board 105 in accordance with a signal input from the outside through the electric connector 108. Is done by. The driving element 103 is provided with a sealing material 112 for preventing ink from entering the mounting portion. As methods for forming high-density, high-precision nozzles and ejection openings in such an ink jet recording head, methods disclosed in Japanese Patent Laid-Open Nos. 5-330066 and 6-286149 have been proposed.

  As for the formation of the ink supply port 110, a method of forming a supply port etched perpendicularly to the Si (110) substrate as disclosed in JP-A-10-138478 is known.

  When the ink jet recording head having such a configuration is elongated, the ink supply port formed by the above-described method is arranged with respect to one nozzle row as shown in FIG. 11 showing a schematic plan view. A plurality of ink supply ports 110 are provided, and a beam 115 for maintaining the mechanical strength of the silicon substrate 301 is provided. Further, a method for maintaining the mechanical strength of the silicon substrate 301 by increasing the thickness of the silicon substrate 301 as compared with a small-sized ink jet recording head is conventionally known.

  However, the conventional ink jet recording head as described above has the following problems.

  By providing the beam 115, the nozzle 116 is generated on the beam. In this nozzle, the flow resistance to the ink discharge port 102 is particularly large, and the ink refill frequency is particularly low.

  Further, as the head becomes longer, the mechanical strength of the beam 115 part inevitably becomes lower than that of the ink jet recording head having a small ink supply port 110, and there are many damages in the manufacturing process of the ink jet recording head, and the yield. Has led to a decline.

As a second conventional example, as means for solving the above problems, an ink supply port having a tapered cross section as shown in FIGS. 12 (a), (b), (c), (d), and (e) is provided. A method of arranging on a staggered pattern has been proposed.
JP-A-5-33066 JP-A-6-286149 JP-A-10-138478

  However, when the ink supply ports having a tapered cross section are arranged in a staggered manner as described above, the back surface of the substrate is larger than the surface of the substrate on which the electrothermal conversion element is provided. In order to prevent the ink supply port arrays from being connected to each other, each ink supply port array on the back surface is shown in FIGS. 12 (a), 12 (b), 12 (c), 12 (d) and 12 (e). It is necessary to take a sufficient distance (L1) between the wall surfaces of the ink supply ports adjacent to each other (inside each row), and as a result, the distance (L2) between the ejection port rows arranged in a staggered pattern is increased. It was.

  As described above, when the distance (L2) between the ejection port arrays becomes large, when adjacent pixels are recorded by ejection ports belonging to different ejection port arrays, the distance (L2) between the ejection port arrays and A difference in ink ejection time corresponding to the scanning speed in the X direction occurs. When ink is applied to adjacent pixels with a time difference, the ink that has been applied later may be affected by the adjacent ink that has been previously applied, and some of the ink may move to the adjacent pixel. In this case, the same type and amount of ink is applied per pixel, and the optical density of the recorded material differs between adjacent pixels, resulting in defects such as white stripes and black stripes as an image. The effect of this ink ejection time difference varies depending on the pixel density, ink characteristics and ejection amount, and the recording material, but is generally noticeable in recording materials suitable for higher image quality recording such as glossy paper. In either case, the difference becomes more noticeable as the difference in the ink ejection time is larger.

  The present invention is characterized in that the ink supply ports are arranged in a staggered manner in a plurality of rows, and at least the wall surfaces of the ink supply ports adjacent to each other (inside each row) are parallel to each other. . By adopting the above-described configuration, the distance (L2) between the ejection port arrays in the conventional example can be made sufficiently small. As a result, ink is adjoined to adjacent pixels belonging to the different ejection port arrays. An ink jet head suitable for higher quality recording is provided at a low cost because the time difference for driving is reduced.

  Further, by forming the ink supply port by so-called vertical anisotropic etching, a high-performance inkjet head having a good manufacturing yield is provided.

  In the present invention, the ink supply ports are arranged in a staggered manner in a plurality of rows, and the wall surfaces of the ink supply ports adjacent to each other (inside each row) are parallel to each other, and each discharge port row is arranged. By shortening the distance between them, it is possible to provide an ink jet head suitable for high-quality recording with a short ink ejection time difference.

  Further, by forming the ink supply port by so-called vertical anisotropic etching, it is possible to provide a high-performance inkjet head with high accuracy and good manufacturing yield.

Example 1
1 to 5 are views for explaining a first embodiment of the present invention. FIG. 1 is a schematic external perspective view of the first embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view, FIG. 3 is a schematic cross-sectional view, FIG. 4A is a schematic plan view schematically showing the upper surface of the ink jet recording head of this embodiment, and FIG. FIGS. 4B and 4C are cross-sectional views taken along lines AA and BB in FIG. 4A, respectively, and FIG. 5 schematically illustrates the structure of an ink jet recording apparatus using the ink jet recording head of the present invention. It is the perspective view shown in.

  In the ink jet recording head of the present invention, a heater 111 is provided on a silicon substrate 101 and nozzles are formed by a nozzle material 113. Ink is supplied from the ink common liquid chamber 117 formed in the support member 106 through the base plate 104 to the heater 111 from the back surface of the silicon substrate 101 through the ink supply port 110 formed as a hole penetrating the silicon substrate 101. Is done.

  The ink supply port 110 may be formed by any method as long as the adjacent ink supply port wall surfaces of the ink supply port array can be formed in parallel with each other. For example, the ink supply port 110 may be formed using a silicon anisotropic etching method. Alternatively, the silicon substrate 101 may be formed by machining. In this example, a silicon substrate 101 having a surface orientation of (110) was used to form a vertical ink supply port (so that adjacent walls are parallel because each column is vertical) by so-called anisotropic etching. .

  Printing is performed by applying electrical energy to the heater 111 to heat and foam the ink, thereby ejecting the ink from the ejection port 102. Application of electric energy to the heater 111 is performed by a transistor circuit in the driving element 103 provided on the silicon substrate 101 through the electric circuit board 107 and the flexible circuit board 105 in accordance with a signal input from the outside through the electric connector 108. Is done by. The driving element 103 is provided with a sealing material 112 for preventing ink from entering the mounting portion.

  In the present invention, two nozzles 114 are provided, and the ink supply ports 110 are arranged in a staggered manner as shown in FIG. 4A corresponding to each of the nozzles 114. Since the ink supply ports are arranged in a staggered manner, the AA cross section and the BB cross section in FIG. 4A have shapes as shown in FIGS. 4B and 4C. For this reason, the mechanical strength of the silicon substrate 101 is also improved. Further, since all the nozzles 114 are arranged at the edge of the ink supply port 110, the ink refill characteristics of each nozzle 114 are also uniformly improved.

  FIG. 5 schematically shows an ink jet recording apparatus using the ink jet recording head of the present invention. In FIG. 5, four inkjet recording heads 120 of the present invention are used, each of which is filled with yellow, magenta, cyan, and black colors. These ink jet recording heads have a long length by adopting the above-described structure, and as shown in FIG. Therefore, when printing, without moving the ink jet recording head 120, the recording paper 201 is attracted to the paper conveying belt 202 and passes under the ink jet recording head 120 once to complete the printing. It is.

  The present invention is characterized in that the ink supply ports are arranged in a zigzag manner in a plurality of rows as described above, and the wall surfaces of the ink supply ports adjacent to each other (inside each row) are parallel to each other. And By adopting the above-described configuration, the distance (L2) between the ejection port arrays in the conventional example can be made sufficiently small. As a result, ink is adjoined to adjacent pixels belonging to the different ejection port arrays. An ink jet head suitable for higher quality recording is provided at a low cost because the time difference for driving is reduced.

  A specific ink supply port forming method of the present invention will be described below with reference to FIG. 6 (schematic cross-sectional view) in the order of steps.

(1) 14000 ３０１ of SiO ₂ 302 is formed on a silicon substrate 301 having a substrate surface orientation (110) by a thermal oxidation method, and a desired pattern for providing an ink supply port is formed by photolithography as shown in FIG. did.

(2) A1 _99.5 Cu _0.5 was deposited and patterned to form a lower layer wiring 305 and a sacrificial layer 304. The etching sacrificial layer is etched in a short time because the etching rate is much faster than the Si wafer when etching proceeds from the back surface and the etchant reaches the sacrificial layer, and an opening corresponding to the sacrificial layer pattern can be opened. is there.

  The long side of the sacrificial layer was 3 mm, and the width was 160 μm.

  (3) An etching stop layer 306 was formed by depositing and patterning 6000 mm of SiN film on the substrate surface by plasma CVD.

  (4) Using plasma CVD, an SiN film was deposited by 7000 mm to form an interlayer insulating film 307.

  Further, a contact hole 308 is formed in the interlayer insulating film using dry etching.

  (5) An ink discharge pressure generating heater unit 309 was formed by depositing and patterning 600 μm of TaSiN in accordance with the ink supply port. Further, an AlCu film was formed as an electrode 310 for power supply.

  (6) Next, 3000 nm of plasma CVD SIN was deposited and patterned as the heater protective film 311.

  (7) In order to protect the heater from cavitation due to ink bubbling, 3000 liters of Ta was deposited and patterned to form an anti-cavitation film 312.

  (8) In order to increase the adhesion of the resin nozzle and to protect the back surface from the alkali etchant, the heater part and the ink are formed by applying and baking 2 μm of a highly corrosion-resistant resin film (HIMAL) 313. The supply port was exposed by patterning.

  (9) In order to secure the ink flow path, a resin polymethylisopropenyl ketone (Tokyo Ohka ODUR-1010) was patterned using lithographic as a nozzle mold material 314 that can be dissolved with a strong alkali or an organic solvent.

  (10) An ink flow path layer was formed on the ink flow path pattern using the photosensitive resin 315 shown in Table 1.

  (11) Next, the coating resin layer of the flow path is patterned to form the ink discharge port 316 corresponding to the heater portion and the external connection portion of the electrode. Thereafter, the coating resin layer was cured by heat.

  (12) A corrosion-resistant resin protective film (OBC Tokyo Ohka) 317 is formed with a corrosion-resistant resist to protect the nozzle forming surface side of the substrate.

  (13) The resin protective film and the insulating film on the back surface are exposed to the wafer surface by removing the pattern portion 318 of the ink supply port using photolithography. The shape of this pattern is formed so as to have a mirror image relationship with the sacrificial layer as shown in FIG.

  (14) An etching leading hole 319 is opened in the vicinity of the narrow angle of the parallelogram to the back surface (shown in FIG. 4A).

  (15) The top surface of this substrate was covered with a corrosion-resistant resin protective film 317.

  (16) This substrate was immersed in TMAH (tetramethylammonium hydride) for 9 hours and anisotropically etched so that the (111) plane appeared.

  A through hole 320 having a tapered cross section is formed.

  (17) The SiN film of the etching stop layer 306 was partially removed by CDE (chemical dry etching) to open the ink supply port 321.

  (18) The protective film 317 is removed, and finally the ink flow path forming material is removed to secure the ink flow path 322. (18) The corrosion-resistant resin protective film 317 covering the upper surface of the silicon substrate is removed.

  In the above embodiment, two rows of ink supply ports are provided, but there is no particular limitation, and providing three or more rows is an effective means if wiring is possible.

(Second embodiment)
A second embodiment according to the present invention will be described with reference to FIGS. 7 (a), (b) and (c).

  The difference from the first embodiment of the present invention is that only the wall surfaces of the ink supply ports adjacent to each other are formed in parallel, and the other wall surfaces are formed in a tapered shape.

  As a specific means for forming the ink supply port as described above, it is formed by machining such as a diamond blade having a tapered one end.

1 is a schematic perspective view showing a first embodiment of an ink jet recording head of the present invention. FIG. 1 is a schematic cross-sectional perspective view of a main part of an ink jet recording head of the present invention. FIG. 2 is a schematic cross-sectional view of a main part of the ink jet recording head of the present invention. (A) is a schematic top view of the main part of the inkjet recording head of the present invention, (b) is a cross-sectional view taken along the line AA in (a), and (c) is a cross-sectional view taken along the line BB in (a). . 1 is a schematic perspective view of a recording apparatus using an ink jet recording head of the present invention. FIG. 3 is a dual cross-sectional view showing a process flow for forming an ink supply port of the ink jet recording head of the present invention. (A) is a schematic top view showing a second embodiment of the ink jet recording head of the present invention, and (b) is a compound cross section taken along A-A in the cross section showing the second embodiment of the ink jet recording head of the present invention. FIG. 4C is a dual cross-sectional view taken along the line BB showing the second embodiment of the ink jet recording head of the present invention. FIG. 6 is a schematic perspective view of a conventional inkjet recording head. FIG. 6 is a schematic cross-sectional perspective view of a main part of a conventional ink jet recording head. FIG. 6 is a schematic cross-sectional view of a main part of a conventional ink jet recording head. A schematic top view of the main part of a conventional inkjet recording head. (A)-(e) is a typical perspective view and sectional drawing which show a 2nd prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Silicon substrate 102 Ink discharge port 103 Drive element 104 Base plate 105 Flexible circuit board 106 Support member 107 Electric circuit board 108 Electric connector 109 Cap receiver 110 Ink supply port 111 Heater 112 Sealing material 113 Nozzle material 114 Nozzle 115 Beam 117 Ink common liquid Chamber 120 Inkjet recording head 201 Recording paper 202 Paper transport belt 301 Silicon substrate 302 SiO ₂
304 Sacrificial layer 305 Lower layer wiring 306 Etching stop layer 307 Interlayer insulating film 308 Contact hole 309 Heater part 310 Power supply electrode 311 Heater protective film 312 Anti-cavitation film 313 Resin film 314 Nozzle mold material 315 Photosensitive resin (CR)
316 Ink discharge port 317 Corrosion-resistant resin protective film 318 Pattern portion of ink supply port 319 Etching leading hole 320 Through hole 321 Ink supply port 322 Ink flow path

Claims (3)

A plurality of electrothermal conversion elements that convert applied electrical energy into thermal energy in accordance with an electrical signal input from the outside,
A plurality of nozzles arranged in rows corresponding to the electrothermal conversion elements, and bubbling and discharging ink with the thermal energy;
A substrate on which the plurality of electrothermal conversion elements and the plurality of nozzles are disposed;
A plurality of ink supply ports that are formed as through-holes in the thickness direction of the substrate and supply ink to the plurality of nozzles;
In the inkjet recording head in which the plurality of ink supply ports are arranged in a plurality of rows in a staggered manner,
An inkjet head characterized in that at least wall surfaces of adjacent ink supply ports in the ink supply port array are parallel. The substrate is made of Si;
The electrothermal conversion element is formed on the (110) surface of the Si substrate,
The ink supply port formed as a through-hole in the thickness direction of the substrate is perpendicular to the surface on which the electrothermal conversion element is disposed, and the wall surface of the ink supply port is the (111) surface of the Si substrate. The ink jet recording head according to claim 1, wherein the ink jet recording head is formed. A method for manufacturing an ink jet recording head according to the second claim,
An ink jet recording head manufacturing method comprising forming the ink supply port by anisotropically etching the Si substrate.

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