JP2007283632A - Inkjet recording head and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a printing speed decrease caused by a drop in ink refilling of an ink liquid chamber beam part, and deterioration of a printing quality. <P>SOLUTION: (1) In an IJ head with delivering openings 202 arranged in the shape of an array and with a beam structure in a liquid chamber, the delivering openings 202 in the vicinity of the beam part are brought near to the liquid chamber side, thereby making a flow resistance to ink of the nozzle equivalent to that of nozzles of the other part. (2) A power supplying electrode of a heating heater 204 and a part of a through-hole are formed on the beam part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that forms ink droplets by ejecting ink from a discharge port onto a recording material.

  The ink jet recording apparatus is a so-called non-impact recording type recording apparatus. High-speed recording and recording on various recording media are possible, and there is a feature that noise during recording hardly occurs. For this reason, it is widely adopted as a device that bears a recording mechanism such as a printer, a word processor, a facsimile machine, and a copying machine.

  Inkjet recording is a method in which minute droplets are ejected from minute ejection ports and recording is performed on a recording paper. A typical method is a method using an electrothermal conversion element. Such ink jet recording is generally composed of an ink jet recording head having nozzles for forming droplets and a supply system for supplying ink to the head. In an ink jet recording head using an electrothermal conversion element, an electrothermal conversion element is provided in a pressurizing chamber, and an electric pulse serving as a recording signal is applied thereto to give thermal energy to the recording liquid. The bubble pressure at the time of foaming (boiling) of the recording liquid caused by the change is used for ejecting recording droplets.

  In the case of an ink jet recording head using the electrothermal conversion system as described above, a system (edge shooter) in which a recording liquid is ejected in parallel to the substrate on which the electrothermal conversion elements are arranged and the electrothermal conversion elements are arranged. There is a method (side shooter) in which the recording liquid is ejected perpendicularly to the substrate. Hereinafter, a specific configuration of the ink jet recording head will be described by taking a side shooter as an example.

  FIG. 6 is a perspective view of the recording head of the side shooter, and FIG. 7 is a plan view of the recording head. FIG. 7A is a top view of the recording head as viewed from the ink ejection direction, and FIGS. 7B and 7C are cross-sectional views taken along lines AA and BB in FIG. 7A, respectively.

  A plurality of discharge ports 202 for discharging ink are opened on the surface side near the center of the recording element substrate 201, and a heater (not shown) for foaming ink corresponding to each discharge port is provided as a recording element. It is formed on the substrate 201.

  Electrical wiring from the heater is connected to a transistor circuit for driving the heater. There are known a method of fabricating this transistor circuit on a recording element substrate and a method of mounting a separately fabricated element on a recording element substrate. Usually, in the recording element substrate 201 having a relatively small number of heaters, a method of forming a transistor circuit on the recording element substrate 201 is generally used. However, in order to widen the printing width, a relatively large number of heaters are used. In a recording element substrate in which a transistor circuit is formed, the yield of the recording element substrate is drastically reduced in the configuration in which the transistor circuit is formed. Therefore, the method of mounting the element in which the transistor circuit is formed separately is mounted on the recording element substrate. However, this is advantageous in terms of yield. 6 and 7 show a conventional example in which a transistor circuit built in a separate drive element 205 is mounted.

  In FIGS. 6 and 7, the wiring from the heater is multilayered via through-holes to be described later, and each extends to the drive element 205 mounting portion on the recording element substrate 201. The drive elements mounted on the heater are electrically connected to each other. Connected. The drive element 205 is connected to the recording element substrate 201 by a COB (chip on board) connection method using an anisotropic conductive film, a solder bump, or the like. In addition to the transistor circuit, the driving element 205 includes a logic circuit for driving the transistor, and a signal for driving the logic circuit is connected to the flexible film 206 via the recording element substrate 201. . Further, the flexible film 206 is connected to a circuit board 207 made of a composite material such as glass epoxy, and an electric connector 208 for inputting an electric signal from the outside is mounted on the circuit board 207.

  When the electrode portion is exposed, the electrical connection portion of the drive element 205 and the flexible film 206 is adhered to the electrode by droplets splashed from the ejection port or ink splashed from the paper, and corrodes the electrode and its underlying metal. The electrode part is covered and sealed with a sealing agent (not shown) excellent in sealing properties and ion blocking properties such as epoxy resin.

  Here, FIG. 8 is a plan view of the vicinity of the ejection opening of the recording head. FIG. 8A is a top view of the recording head viewed from the ink discharge direction, and FIG. 8B is a cross-sectional view taken along the line AA of FIG. 8A.

  A through hole 217 is provided between the ejection pressure generating element 204 on the recording element substrate 201 and the ink supply port 203, and is electrically connected to the output terminal and the common electrode of the driving element 201 through an electrode (not shown).

  In the recording element substrate 201 and the base plate 211 disposed on the back surface thereof, an ink supply port 203 for guiding ink supplied from the common liquid chamber 210 formed in the support member 212 has a length substantially equal to the length of the ejection port array. Now it is open. As the opening means of the ink supply port 203, machining by laser, sandblasting, or the like, or anisotropic etching by an alkaline solution or the like when the recording element substrate 201 is single crystal silicon can be used.

  The common liquid chamber 210 further communicates with the ink supply tube 214, and is configured to receive ink supply from an ink tank (not shown) outside the ink jet recording head when ink is ejected.

  In general, an ink jet recording apparatus that performs printing by scanning an ink jet recording head having such a configuration with respect to a recording material such as paper while discharging ink is widely known. As shown, an inkjet recording apparatus that can perform printing at high speed by fixing a head having a long print width on a conveyance belt that conveys a recording material and scanning the recording material has been conventionally known. In the example of the ink jet recording apparatus shown in FIG. 9, four ink jet recording heads having a full paper width are arranged and full color printing is performed by ejecting four colors of ink of yellow, magenta, cyan, and black. Is to do.

  However, the ink jet recording head and the ink jet recording apparatus described above have the following two problems.

  The first problem is that the strength of the recording element substrate 201 is low. The cause of the decrease in strength is that an ink supply port 203 having a printing width must be opened on the recording element substrate 201. In such a configuration, as the recording element substrate 201 is elongated, the strength is remarkably reduced, and the recording element substrate 201 is easily damaged during the manufacturing or in use.

  Second, a portion of the orifice plate formed of the nozzle material 215 corresponding to the portion directly above the ink supply port 203 is greatly recessed or protrudes, which adversely affects the print quality. Since this portion is directly above the ink supply port 203, it is not supported with respect to the recording element substrate 201, and is composed of the nozzle material 215 having a thickness of several μm to several tens of μm. Depending on conditions, the liquid is recessed toward the common liquid chamber side 210 or protrudes in the recording liquid flying direction. This deformation also changes the shape of the discharge port 202, so the flying direction of the recording liquid is not fixed, and the quality of the output image is reduced.

  As shown in FIG. 10, a method has been devised to solve the above problem by providing a beam in the ink supply port. FIG. 10 is a plan view of the vicinity of the ejection opening of the recording head. 10A is a top view of the recording head as viewed from the ink discharge direction, FIG. 10B is a cross-sectional view taken along the line AA in FIG. 10A, and FIG. 10C is the view in FIG. It is a figure of BB cross section.

  That is, as shown in FIG. 10, a beam 218 is formed in a ladder shape in the ink supply port 203, the strength of the recording element substrate 201 is maintained, and the nozzle agent 215 forming the orifice plate is supported by the beam 218. Ink jet recording heads have been developed to prevent deterioration of print quality.

For example, Patent Document 1 and Patent Document 2 can be cited as conventional examples.
Japanese Patent Laid-Open No. 10-230602 JP 2003-31964 A

  However, the ink jet recording head and the ink jet recording apparatus described above have the following problems.

  That is, in order to improve the printing speed in the ink jet recording apparatus, it is necessary to shorten the time required from ink ejection to refilling in each recording element and pressure chamber.

  However, by forming the beam in the common liquid chamber, in some pressure chambers corresponding to the position where the beam is formed, the flow path length to the common liquid chamber becomes redundant and the flow resistance to the recording liquid increases. Resulting in. As a result, at the portion where the beam is installed, the refill time of the recording liquid is locally increased, and the print quality of the portion is deteriorated and the printing speed is lowered.

  In the present invention, the recording liquid is placed in the pressure chamber 216 by disposing the discharge pressure generating element 204 and the discharge port 202 in the vicinity of the beam in the common liquid chamber close to the ink supply port side. The flow resistance to the discharge port when refilling is equal to or less than that of the other pressure chambers, and the refilling time of the recording liquid is shortened to improve printing.

  Also, the discharge pressure generating element 204 and the discharge port 202 are moved to the ink supply port side by forming at least a part of a feeding electrode (not shown) and a through hole of the discharge pressure generating element 204 on the beam. Is realized.

  As described above, the present invention improves the mechanical strength of the recording element substrate of the ink jet recording head and maintains the structure for keeping the print quality high, while also improving the printing speed. It is possible.

  The above description has been made for all of the side shooter bubble jet (registered trademark) inkjet recording head and inkjet recording head. Of course, the edge shooter inkjet recording head and the piezo inkjet recording head are used. In addition, the present invention can be applied, and the effect is not different from the above description. In the present invention, the number of recording element substrates to be mounted and the print width thereof are not limited, and the effects of the present invention can be similarly obtained even when an arbitrary print width is set.

  FIGS. 1 to 5 are views for explaining an ink jet recording head according to a first embodiment of the present invention. FIG. 1 is a schematic perspective view of the ink jet recording head of the present invention, and FIG. 2B is a cross-sectional view of the AA cross section of FIG. 2A, FIG. 2C is a cross-sectional view of the BB cross section of FIG. 2A, and FIG. 4A is a cross-sectional view schematically showing the mechanism, FIG. 4A is a top plan view in the vicinity of the ejection port of the head, FIG. 4B is a cross-sectional view in the AA section of FIG. 4A, and FIG. FIG. 4A is a cross-sectional view taken along the line BB in FIG. 4A, FIG. 4D is a cross-sectional view taken along the line CC in FIG. 4A, and FIG. 5 is a schematic perspective view of the ink jet recording apparatus.

  In FIG. 1, the inkjet recording head of the present invention has a plurality of ejection ports 202 for ejecting ink on the surface side near the center of the recording element substrate 201, and ink droplets ejected from the ejection ports 202 It is for recording.

  As shown in FIGS. 2 and 3, a heater 204 is formed on the recording element substrate 201 corresponding to each discharge port 202, and the heater 204 is energized and heated to foam ink, The ink that is the recording liquid is ejected from the ejection port 202 by the kinetic energy.

  The electrical wiring from the heater 204 extends to the drive element 205 mounting portion on the recording element substrate 201, and is electrically connected to the drive element mounted thereon. The drive element 205 is connected to the recording element substrate 201 via a anisotropic conductive film by a COB (chip on boad) connection method. In addition to the transistor circuit, the driving element 205 includes a logic circuit for driving the transistor, and a signal for driving the logic circuit is connected to the flexible film 206 via the recording element substrate 201. . Further, the flexible film 206 is connected to a circuit board 207 made of a composite material such as glass epoxy, and an electric connector 208 for inputting an electric signal from the outside is mounted on the circuit board 207.

  When the electrode portion is exposed, the electrical connection portion of the drive element 205 and the flexible film 206 is adhered to the electrode by droplets splashed from the ejection port or ink splashed from the paper, and corrodes the electrode and its underlying metal. The electrode portion is covered and sealed with a silicon resin sealant (not shown) having excellent sealing properties and ion blocking properties.

  In the recording element substrate 201 and the base plate 211 disposed on the back surface thereof, an ink supply port 203 for guiding ink supplied from the common liquid chamber 210 formed in the supporting member 212 is a beam over the entire area of the ejection port array. At 218, a plurality of openings are divided into ladders. As the opening means of the ink supply port 203, machining by laser, sandblasting, or the like, or anisotropic etching by an alkaline solution or the like when the recording element substrate 201 is single crystal silicon can be used.

  The common liquid chamber 210 communicates with the recording element substrate 201 and further communicates with the ink supply tube 214. When ink is ejected, ink is supplied from an ink tank (not shown) outside the ink jet recording head through the ink supply tube 214.

  As shown in FIG. 4, one of the power supply electrodes (not shown) from the heater 204 is on the output side of the mounting portion of the drive element 205 provided on the recording element substrate 201 on the opposite side of the ink supply port 203. And the other one is multi-layered via a through hole 217 provided on the recording element substrate 201 on the ink supply port 203 side, and is folded and connected to the common electrode of the driving element 205 Has been.

The gist of the present invention is as follows:
The discharge pressure generating element 204, the discharge port 202, and the pressure chamber 216 in the vicinity of the beam portion in the common liquid chamber are arranged close to the ink supply port side with respect to other portions, and the recording liquid is supplied to the pressure chamber 216. The flow resistance up to the discharge port when refilling is equal to or at least relaxed to other parts.

  In addition, a feeding electrode (not shown) and a through hole of the discharge pressure generating element 204 are formed on the beam.

  FIG. 5 is a schematic perspective view of the ink jet recording apparatus. The ink jet recording apparatus of this embodiment is equipped with four recording heads 220, and each of them is injected with ink of each color of yellow, magenta, cyan, and black, and these four heads are used. By printing, full color printing is realized.

  Under the recording head 220, a recording material conveyance belt is provided so that the recording material 302 can be conveyed in a direction perpendicular to the nozzle array arrangement direction of the recording head 220 (corresponding to the arrangement direction of the recording element substrate 201). 301 is provided.

  According to the present invention, the printing speed can be improved because the refilling time of the recording liquid can be shortened while increasing the strength of the recording element substrate.

1 is a schematic perspective view of a recording head according to a first embodiment of the present invention. 2A is a top plan view of the recording head of the first embodiment of the present invention, FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A, and FIG. 2C is a cross-sectional view taken along line BB in FIG. 1 is a schematic cross-sectional view of a recording head according to a first embodiment of the present invention. FIG. 4A is a top plan view of the vicinity of the ejection opening of the recording head of the first embodiment of the present invention, FIG. 4B is a cross-sectional view taken along the line AA in FIG. 4A, and FIG. 1 is a schematic perspective view of an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 6 is a schematic perspective view of a conventional inkjet recording head. FIG. 6A is a top plan view of a conventional recording head, FIG. 6B is a cross-sectional view taken along line AA in FIG. 6A, and FIG. 6C is a cross-sectional view taken along line BB in FIG. FIG. 9A is a top plan view in the vicinity of a discharge port of a conventional recording head, and FIG. FIG. 10 is a schematic perspective view of a conventional inkjet recording apparatus. 10A is a top plan view of the vicinity of a discharge port of a conventional recording head, FIG. 10B is a cross-sectional view taken along line AA in FIG. 10A, and FIG. 10C is a cross-sectional view taken along line BB in FIG.

Explanation of symbols

201 Recording Element Substrate 202 Discharge Port 203 Ink Supply Port 204 Heater 205 Drive Element 206 Flexible Film 207 Circuit Board 208 Electric Connector 210 Common Liquid Chamber 211 Base Plate 212 Support Member 213 Front Plate 214 Ink Supply Tube 215 Nozzle Material 216 Pressure Chamber 217 Power Supply Through-hole of electrode 218 Beam 220 Recording head 301 Recording material conveyance belt 302 Recording material

Claims (2)

A recording liquid discharge port and a pressurizing chamber for discharging a recording liquid to a recording material, and a recording element substrate in which a plurality of discharge pressure generating elements for applying kinetic energy to the recording liquid are provided in a row. Have
Ink supply ports for supplying a recording liquid to the plurality of ejection pressure generating elements are formed in a row through the recording elements,
In the ink jet recording head in which one or more beam structures are formed in the ink supply port, the discharge port and the discharge pressure generating element in the vicinity of the beam portion are arranged close to the ink supply port side. An inkjet recording head.   2. The ink jet recording head according to claim 1, wherein at least a part of a power supply electrode and a through hole for supplying electric energy to the ejection pressure generating element is formed on the beam.

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