JP4646665B2 - Inkjet recording head - Google Patents

Description

  The present invention relates to an ink jet recording head used in a recording apparatus that performs a recording operation by forming droplets by discharging a liquid such as ink from an ejection port.

  The ink jet recording head of the present invention is a general printing apparatus, a copying machine, a facsimile having a communication system, an apparatus such as a word processor having a printing unit, and an industrial combination combined with various processing apparatuses. It can be applied to a recording apparatus.

  The ink jet recording apparatus is a so-called non-impact recording type recording apparatus, and is characterized by being capable of recording on various recording media at high speed and hardly causing noise in recording. For this reason, the ink jet recording apparatus is widely adopted as an apparatus that bears a recording mechanism such as a printer, a copier, a facsimile, a word processor, or the like.

  A typical ink ejection method for a recording head mounted on such an ink jet recording apparatus is one that uses an electromechanical transducer such as a piezo element, or generates heat by irradiating an electromagnetic wave such as a laser. And the like that discharge ink droplets, or those that heat ink by an electrothermal conversion element having a heating resistor and discharge ink droplets by the action of film boiling, are known.

  An ink jet recording head using an electrothermal conversion element is provided with an electrothermal conversion element in a recording liquid chamber, and an electric pulse serving as a recording signal is supplied thereto to generate heat, thereby giving thermal energy to the ink. Recording is performed on a recording medium by ejecting minute ink droplets from minute ejection ports using bubble pressure at the time of foaming (boiling) of the recording liquid caused by the liquid phase change. An ink jet recording nozzle for discharging ink droplets and a supply system for supplying ink to the nozzle are provided.

  In recent years, the resolution of ink jet recording apparatuses has been increased, and in particular, even in an ink jet recording head used for forming image quality, the resolution of the discharge port array for discharging individual droplets has been increased, and further images are formed. The size of the ejected ink droplets also tends to be reduced to 5 pl or 2 pl.

  Further, in order to realize an image having a high gradation, an ink jet recording head discharges different ink droplet sizes with the same color. For example, as disclosed in Patent Document 1, a plurality of large-diameter ejection port arrays that eject relatively large ink droplets across an ink supply port (common liquid chamber) that supplies ink, and relatively small ink Forming a plurality of small-diameter ejection port arrays for ejecting droplets, and ejecting large and small ink droplets from the large-diameter ejection port and the small-diameter ejection port, respectively, to form large and small ink dots on the recording medium (See FIG. 14). Further, a configuration has been devised in which large-diameter discharge ports and small-diameter discharge ports are alternately arranged to enable formation of large dots and small dots at low cost (see FIG. 15).

  A pigment ink may be used to improve weather resistance such as light resistance and water resistance.

Since ink evaporates and the viscosity increases over time, the print head may be left for a long time without performing a recording operation, or there may be nozzles that are not used for a long time even when performing a recording operation. May cause ejection failure such as non-ejection or landing landing when trying to perform a recording operation (see Patent Document 2). In particular, as the diameter of the discharge port is reduced, such a discharge failure tends to appear more remarkably. For this reason, preliminary ejection is performed before the recording operation (see Patent Document 3) or the temperature is adjusted to warm the recording head (see Patent Document 4) so that the recording operation is normally performed.
JP 2003-31965 A JP-A-9-226125 JP 2003-312025 A JP 2002-240252 A

  In recent years, there has been a tendency to reduce the diameter of the discharge port in order to reduce the size of the droplet, so that when ink with a high viscosity is used, non-ejection or landing of ink is more likely at the beginning of the recording operation. It tends to occur prominently. Therefore, it is necessary to increase the degree of preliminary ejection before the recording operation or to warm the recording head by adjusting the temperature, which increases the amount of ink consumed for preliminary ejection. Therefore, the time until the recording operation starts becomes long.

  The present invention has been made in view of the above problems. Even when ink having a high viscosity is ejected from a relatively small-diameter ejection port, non-ejection or landing of ink occurs at the initial stage of the recording operation. An object of the present invention is to provide an ink jet recording head that can suppress the amount of ink consumed for preliminary ejection and the time required to start a recording operation.

In order to achieve the above object, an ink jet recording head of the present invention is provided with a plurality of ejection ports for ejecting ink and corresponding to each of the plurality of ejection ports, and ejects the ink from the plurality of ejection ports. A plurality of recording elements that generate energy to be used, a plurality of ink flow paths that communicate with the plurality of ejection ports and that correspond to each of the plurality of recording elements, and the plurality of ink flows A plurality of ink flow paths communicating with the plurality of ejection openings, and a first ink flow path communicating with a relatively large diameter ejection opening and a relatively small diameter. In the ink jet recording head, the first ink flow path and the second ink flow path are alternately arranged so as to be adjacent to each other. 1 ink flow path Further includes a third ink flow path for communicating the second ink flow path from each other. Further, the first and second ink flow paths each extend in a direction perpendicular to the arrangement direction of the ink flow path rows, and the communication portion of the third ink flow path with the second ink flow path is The second ink flow path is located at the same position as the relatively small-diameter ejection port in the extending direction of the second ink flow path or at a position farther from the common liquid chamber.

  According to the above-described ink jet recording head of the present invention, even when ink having a high viscosity is discharged from a discharge port having a relatively small diameter, it is possible to suppress the occurrence of non-ejection or landing of ink at the initial stage of the recording operation, and It is possible to reduce the amount of ink consumed for ejection and the time until the start of the recording operation.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIGS. 1 to 6 are diagrams for explaining the respective configurations and relationships of a suitable head cartridge, recording head, and ink tank in which the present invention is implemented or applied. Hereinafter, each component will be described with reference to these drawings.

  A recording head (inkjet recording head) H1001 according to this embodiment is one constituent element of the recording head cartridge H1000, as can be seen from the perspective views of FIGS. 1A and 1B, and the recording head cartridge H1000. Is composed of a recording head H1001 and ink tanks H1900 (H1901 to H1904) detachably provided on the recording head H1001.

  The recording head H1001 discharges ink (recording liquid) supplied from the ink tank H1900 from the discharge port according to the recording information. The recording head cartridge H1000 is detachable from a carriage (not shown) provided in the ink jet recording apparatus main body.

  Ink tank H1901 is an ink tank for black ink, ink tank H1902 is for cyan ink, ink tank H1903 is for magenta ink, and ink tank H1904 is an ink tank for yellow ink. Each of the ink tanks H1901, H1902, H1903, and H1904 is detachable with respect to the seal rubber H1800 side of the recording head H1001, and the respective ink tanks can be exchanged in this manner, so that each ink tank can change each color. The ink tanks for each color can be individually replaced according to different consumption amounts.

Next, each component constituting the recording head H1001 will be described in further detail in order.
(1) Recording Head The recording head H1001 performs recording using an electrothermal transducer (recording element) that generates thermal energy for causing film boiling with respect to ink in accordance with an electrical signal. (Trademark) type side shooter type recording head.

As shown in the exploded perspective view of FIG. 2, the recording head H1001 includes a recording element unit H1002, an ink supply unit H1003, and a tank holder H2000. Further, as shown in the exploded perspective view of FIG. 3, the recording element unit H1002 includes a first recording element substrate H1100, a second recording element substrate H1101, a first plate (first support member) H1200, electric wiring. The ink supply unit H1003 is composed of a tape H1300, an electrical contact substrate H2200, and a second plate (second support member) H1400. The ink supply unit H1003 includes an ink supply member H1500, a flow path forming member H1600, a joint seal member H2300, and a filter. It is composed of H1700 and seal rubber H1800.
(1-1) Recording Element Unit FIG. 4 is a partially exploded perspective view illustrating the configuration of the first recording element substrate H1100.

  The first recording element substrate H1100 has a plurality of recording elements (electrothermal conversion elements) H1103 for ejecting ink on one surface of a Si substrate H1110 having a thickness of 0.5 to 1 mm, and electric power to each electrothermal conversion element H1103. An electric wiring such as Al for supplying the film is formed by a film forming technique. A plurality of ink flow paths and a plurality of ejection openings H1107 corresponding to the electrothermal conversion element H1103 are formed by a photolithography technique, and ink supply openings (common to supply ink to the plurality of ink flow paths) (Liquid chamber) H1102 is formed to open to the opposite surface (back surface). In addition, the recording element substrate H1100 is fixed to the first plate H1200 (see FIG. 3) by bonding, thereby forming a common liquid chamber H1102.

  Referring to FIG. 3, a second plate H1400 having an opening is fixed to the first plate H1200 by bonding, and the electric wiring tape H1300 is connected to the recording element via the second plate H1400. It is held so as to be electrically connected to the substrate H1100. The electrical wiring tape H1300 is for applying an electrical signal for ejecting ink to the recording element substrate H1100. The electrical wiring corresponding to the recording element substrate H1100 and the recording apparatus main body are located in the electrical wiring portion. The external signal input terminal H1301 that receives an electrical signal from the ink supply member H1301 is positioned and fixed on the back side of the ink supply member H1500.

  Referring to FIG. 4, the common liquid chamber H1102 is formed by a method such as anisotropic etching or sandblasting using the crystal orientation of Si. That is, when the Si substrate H1110 has a crystal orientation of <100> in the wafer surface direction and <111> in the thickness direction, it is approximately 54.7 degrees by anisotropic etching with alkali (KOH, TMAH, hydrazine, etc.). Etching proceeds at an angle of. Thus, etching is performed to a desired depth to form a common liquid chamber H1102 composed of a long groove-like through-hole. The electrothermal transducers H1103 are arranged in a staggered pattern in one row on both sides of the common liquid chamber H1102.

  An electric wiring (not shown) such as Al for supplying electric power to the electrothermal transducer H1103 is formed by a film forming technique. Further, electrodes H1104 for supplying electric power to the electric wiring are arranged on both outer sides of the electrothermal transducer H1103, and bumps H1105 such as Au are formed on the electrode H1104 by a thermosonic bonding method. On the Si substrate H1110, an ink channel wall H1106 and an ejection port H1107 for forming an ink channel corresponding to the electrothermal conversion element H1103 are formed of a resin material by a photolithography technique, and an ejection port group H1108. Is formed. Since the ejection port H1107 is provided to face the electrothermal conversion element H1103, the ink supplied from the common liquid chamber H1102 is ejected from the ejection port H1107 by bubbles generated by the heat generation action of the electrothermal conversion element H1103.

  FIG. 5 is a partially exploded perspective view illustrating the configuration of the second recording element substrate H1101.

  The second recording element substrate H1101 is a recording element substrate for ejecting ink of three colors, and three common liquid chambers H1102 are formed in parallel, on both sides of each common liquid chamber H1102. An electrothermal conversion element H1103 and a discharge port H1107 are formed. The number of the common liquid chambers H1102 is not limited to three, and when the same three colors of ink are used, the common liquid chamber H1102 for yellow ink is set in the middle and the common liquid chambers H1102 for magenta ink are arranged on both sides thereof. There may be five configurations in which the common liquid chamber H1102 for cyan ink faces.

  Similar to the first recording element substrate H1100, a common liquid chamber H1102, an electrothermal conversion element H1103, an electrical wiring (not shown), an electrode H1104, and the like are formed on the Si substrate H1110, and a resin material is used as a photopolymerization material. Ink channel walls H1106 and ink discharge ports H1107 are formed by lithography. Similarly to the first recording element substrate H1100, bumps H1105 such as Au are formed on the electrodes H1104 that supply electric power to the electrical wiring.

Next, the first plate H1200 (see FIG. 3 and the like) is formed of an alumina (Al ₂ O ₃ ) material having a thickness of 0.5 to 10 mm, for example. The material of the first plate H1200 is not limited to alumina, and has a linear expansion coefficient equivalent to the linear expansion coefficient of the material of the recording element substrate H1100 and is equivalent to the thermal conductivity of the material of the recording element substrate H1100 or It may be made of a material having an equivalent or higher thermal conductivity. The material of the first plate H1200 is, for example, silicone (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), molybdenum (Mo), tungsten (W) Any of these may be sufficient.

  The first plate H1200 has an ink supply port H1201 for supplying black ink to the first recording element substrate H1100, and an ink supply port H1201 for supplying cyan, magenta, and yellow ink to the second recording element substrate H1101. The ink supply ports H1102 of the recording element substrates H1100 and H101 correspond to the ink supply ports H1201 of the first plate H1200, respectively. The first recording element substrate H1100 and the second recording element substrate H1101 are bonded and fixed to the first plate H1200 with high positional accuracy. The first adhesive used for the bonding is desirably a low viscosity, low curing temperature, cured in a short time, has a relatively high hardness after curing, and has ink resistance. The first adhesive is, for example, a thermosetting adhesive mainly composed of an epoxy resin, and the thickness of the first adhesive layer H1202 shown in FIG. 7 is desirably 50 μm or less.

  3 and 7, the electrical wiring tape H1300 applies an electrical signal for ejecting ink to the first recording element substrate H1100 and the second recording element substrate H1101. The electrical wiring tape H1300 includes a plurality of openings H1 and H2 for incorporating the recording element substrates H1100 and H1101, electrode terminals H1302 corresponding to the electrodes H1104 of the recording element substrates H1100 and H1101, and the electrical wiring. An electrical contact substrate H2200 having an external signal input terminal H1301 for receiving an electrical signal from the recording apparatus main body located at an end of the tape H1300 and an electrode terminal portion (not shown) for electrical connection are provided. The electrode terminal portion and the electrode lead H1302 are connected by a continuous copper foil wiring pattern. The electrical wiring tape H1300 is made of, for example, a flexible wiring board in which wiring has a two-layer structure and a surface layer is covered with a resist film.

  In this case, a reinforcing plate is bonded to the back surface side (outer surface side) of the external signal input terminal H1301 of the electrical contact substrate H2200, thereby improving the flatness. As the reinforcing plate, for example, a material having heat resistance such as 0.5 to 2 mm glass epoxy or aluminum is used. The electrical wiring tape H1300, the first recording element substrate H1100, and the second recording element substrate H1101 are electrically connected to each other. As a connection method, for example, a bump H1105 on the electrode H1104 of the recording element substrate is used. And the electrode lead H1302 of the electric wiring tape H1300 can be electrically bonded by a thermosonic bonding method.

The second plate H1400 is, for example, a single plate-like member having a thickness of 0.5 to 1 mm, and is formed of a ceramic material such as alumina (Al ₂ O ₃ ) or a metal material such as Al or SUS. Yes. However, the material of the second plate H1400 is not limited to these, and has a linear expansion coefficient equivalent to that of the recording element substrates H1100 and H1101 and the first plate H1200, and is equivalent to their thermal conductivity. A material having the above thermal conductivity may be used. The second plate H1400 has openings larger than the outer dimensions of the first recording element substrate H1100 and the second recording element substrate H1101 that are bonded and fixed to the first plate H1200. Further, the back surface of the second plate H1400 is bonded to the first plate H1200 by the second adhesive layer H1203, and the back surface of the electric wiring tape H1300 is fixed to the surface of the second plate H1400 by the third adhesive layer H1306. Is done.

  The first recording element substrate H1100 and the second recording element substrate H1101 are electrically connected to the electrical wiring tape H1300 with a first sealant (not shown) and a second sealant (not shown). Thus, the electrical connection portion is protected from ink corrosion and external impact.

  The first sealant mainly seals the back side of the connecting portion between the electrode terminal H1302 of the electric wiring tape and the bump H1105 of the recording element substrate and the outer peripheral portion of the recording element substrate, and the second sealant is The front side of the connecting portion is sealed. Furthermore, an electrical contact substrate H2200 having an external signal input terminal H1301 for receiving an electrical signal from the recording apparatus main body is thermocompression bonded to the end portion of the electrical wiring tape H1300 using an anisotropic conductive film or the like to be electrically connected. It is connected. The electric wiring tape H1300 is bonded to the second plate H1400 and is bent along one side of the first plate H1200 and the second plate H1400, and the third plate is attached to the side of the first plate H1200. It is bonded by the adhesive layer H1306.

For the second adhesive layer H1203, it is preferable to use an adhesive having low viscosity and capable of forming the second adhesive layer H1203 thinly on the first plate H1200 and having ink resistance. For the third adhesive layer H1306, for example, it is preferable to use a thermosetting adhesive having an epoxy resin as a main component and a thickness of 100 μm or less.
(1-2) Ink Supply Unit Referring to FIG. 3, the ink supply member H1500 is formed by resin molding, for example. As the resin material, it is desirable to use a resin material mixed with 5 to 40% of glass filler in order to improve the shape rigidity.

  As shown in FIGS. 3 and 6, the ink supply member H1500 that detachably holds the ink tank H1900 is a component of the ink supply unit H1003 that guides ink from the ink tank H1900 to the recording element unit H1002. The forming member H1600 is ultrasonically welded to form an ink flow path H1501 from the ink tank H1900 to the first plate H1200.

  A filter H1700 that prevents entry of dust from the outside is joined to the joint H1520 that engages with the ink tank H1900 by welding, and a seal rubber H1800 is attached to prevent evaporation of ink from the joint H1520. Has been.

  The ink supply member H1500 also has a function of holding a detachable ink tank H1900, and has a hole H1503 in which a claw H1910 of the ink tank H1900 is engaged.

Further, the ink supply member H1500 includes an engaging portion for mounting and fixing the recording head cartridge on the carriage by a head set lever, and an abutting portion in the X direction (carriage scan direction) for positioning the carriage at a predetermined mounting position. H1509, an abutting portion H1510 in the Y direction (recording medium conveyance direction), and an abutting portion H1511 in the Z direction (ink ejection direction) are formed. Further, a mounting guide H1601 for guiding the recording head cartridge H1000 to the mounting position on the carriage of the ink jet recording apparatus main body is attached to the ink supply member H1500. The ink supply member H1500 has a terminal fixing portion H1512 for positioning and fixing the electrical contact substrate H2200 of the recording element unit H1002, and a plurality of ribs are provided around the terminal fixing portion H1512 and the terminal fixing portion H1512 is provided. Increases the rigidity of the surface.
(1-3) Coupling of Recording Head Unit and Ink Supply Unit As shown in FIG. 2, the recording head H1001 combines the recording element unit H1002 with the ink supply unit H1003, and further couples it with the tank holder H2000. It is completed by. These couplings are performed as follows.

  Ink does not leak through the ink communication port (ink supply port H1201 of the first plate H1200) of the recording element unit H1002 and the ink communication port (ink communication port H1602 of the flow path forming member H1600) of the ink supply unit H1003. In order to communicate with each other, the respective members are fixed with screws H2400 so as to be pressure-bonded to each other via a joint seal member H2300.

  At this time, the recording element unit H1002 is accurately positioned and fixed with respect to the reference positions (respective abutting portions H1509, H1510, H1511) of the ink supply unit H1003 in the X direction, Y direction, and Z direction.

  The electrical contact substrate H2200 of the recording element unit H1002 is positioned and fixed to one side surface of the ink supply member H1500 by terminal positioning pins H1515 (2 places) and terminal positioning holes H1309 (2 places). The fixing is performed, for example, by crimping a terminal positioning pin H1515 provided on the ink supply member H1500, but may be fixed using other fixing means. FIG. 10 shows the combined state.

  Further, the recording head H1001 is completed by fitting the coupling hole and coupling portion of the ink supply member H1500 with the tank holder into the tank holder H2000 and coupling them.

As described above, the tank holder portion including the ink supply member H1500, the flow path forming member H1600, the filter H1700, and the seal rubber H1800, the recording element substrates H1100 and H1101, the first plate H1200, the wiring substrate H1300, and the second plate. The recording head H1001 is configured by bonding the recording element unit including the H1400 with an adhesive or the like. The completed drawing is shown in FIG.
(2) Description of Print Head Cartridge With reference to FIGS. 1A and 1B, mounting of ink tanks H1901, H1902, H1903, and H1904 to the printhead H1001 constituting the printhead cartridge H1000 will be described.

  Each ink tank H1901, H1902, H1903, and H1904 contains ink of different colors. Further, as shown in FIG. 6, each ink tank is formed with an ink communication port H1907 for supplying the ink in the ink tank to the recording head H1001.

  For example, when an ink tank H1901 containing black ink is attached to the recording head H1001, the ink communication port H1907 of the ink tank H1901 is pressed against a filter H1700 provided in the joint portion H1520 of the recording head H1001, and the ink tank H1901 The black ink is supplied from the ink communication port H1907 to the first recording element substrate H1100 through the first plate H1200 via the ink flow path H1501 of the recording head H1001. Then, the ink supplied to the foaming chamber having the electrothermal conversion element H1103 and the ejection port H1107 is ejected from the ejection port H1107 toward the recording paper as a recording medium by the thermal energy given to the electrothermal conversion element H1103.

  7 is an exploded schematic cross-sectional view of the main part of the recording element unit H1002, and FIG. 10 is a schematic cross-sectional view of the main part of the recording element unit H1002. As shown in FIG. 7, the electrical wiring tape H1300 has a three-layer structure around the bonding portion, and a polyimide base film H1300a on the front side, a copper foil H1300b on the middle, and a solder resist H1300c on the back side.

  An opening H1 into which the first recording element substrate H1100 is inserted and an opening H2 into which the second recording element substrate H1101 is inserted are formed in the electrical wiring tape H1300, and the recording element substrates H1100 and H1101 are formed. The electrode lead H1302 connected to the bump H1005 is exposed in a gold plated state.

  When the recording element unit H1002 is manufactured, first, the second plate H1400 is bonded to the first plate H1200 with the second adhesive layer H1203. The thickness of the second adhesive layer H1203 is suppressed to 0.06 mm or less so that the first recording element substrate H1100 and the second recording element substrate H1101 and the electric wiring tape H1300 can be electrically connected in a plane. It is preferable. Note that the second plate H1400 may be bonded to the first plate H1200 before or after the recording element substrates H1100 and H1101 are bonded to the first plate H1200.

  Next, after applying a first adhesive layer H1202 for bonding the first recording element substrate H1100 and the second recording element substrate H1101 to the first plate H1200, the recording liquid is discharged onto the recording element substrates H1100 and H1101. The plurality of electrothermal conversion elements H1103 or the respective discharge ports H1107 are pressed and fixed together with the relative positional relationship in the wiring surface direction.

Thereafter, a third adhesive layer H1306 for adhering the electric wiring tape H1300 is applied on the second plate H1400, and the first recording element substrate H1100, the electrode H1104 of the second recording element substrate H1101 and the electric wiring tape H1300. After alignment with the electrode lead H1302, the electric wiring tape H1300 is pressed and fixed on the second plate H1400. Then, the bump H1105 on the electrode H1104 of the recording element substrate and the electrode lead H1302 of the electric wiring tape H1300 are electrically joined one by one by a thermal ultrasonic pressure bonding method. In this way, the recording element unit H1002 is manufactured (see FIG. 7A).
(3) Description of Characteristic Configuration of the Present Embodiment Hereinafter, the characteristic configuration of the present embodiment will be described in detail.

  FIG. 11A is a plan view showing a discharge port forming surface of a recording head H1001 according to an embodiment of the present invention. Note that broken lines in the drawing indicate ink flow paths and the like inside the recording head H1001.

  As shown in FIG. 11A, the recording head H1001 includes a first ink channel H2501 communicating with the large-diameter ejection port H2504, a second ink channel H2502 communicating with the small-diameter ejection port H2505, and a first ink channel H2501. And a second ink channel H2502 and a third ink channel H2503 that communicates with the second ink channel H2502, and a common liquid chamber H1102 that communicates with the first ink channel H2501 and the second ink channel H2502. .

  The first ink flow path H2501 communicating with the large diameter discharge port H2504 and the second ink flow path H2502 communicating with the small diameter discharge port H2505 are alternately arranged on both sides of the common liquid chamber H1102 so as to be adjacent to each other along the extending direction. It is arranged. The ink flow paths H2501, H2502 arranged on one side of the common liquid chamber H1102 form a first ink flow path row, and the ink flow paths H2501, H2502 arranged on the other side of the common liquid chamber H1102 are the first. Two ink flow path rows are formed. In the first ink channel row and the second ink channel row, the first ink channel H2501 and the second ink channel are related to the direction perpendicular to the extending direction of the common liquid chamber H1102 shown in FIG. 11A. H2502 are alternately arranged alternately. In each ink flow path row, the large-diameter ejection openings H2504 and the small-diameter ejection openings H2505 are alternately arranged at a pitch of 600 dpi (dot per inch). Focusing only on the large-diameter discharge port H2504, the pitch is 300 dpi. Similarly, focusing only on the small-diameter discharge port H2505, the pitch is 300 dpi.

  As described above, in the recording head H1001 having the configuration in which the large-diameter ejection port H2504 and the small-diameter ejection port H2505 coexist, when performing a normal recording operation, the large droplet ejected from the large-diameter ejection port H2504 is the smaller-diameter ejection port. More than small droplets are ejected from H2505, and small droplets are ejected less frequently than large droplets. In addition, since the small-diameter ejection port H2505 has a small ejection port diameter, when water as the solvent in the ink evaporates and thickens in the vicinity of the ejection port, the first few dots are not normally ejected due to the thickening (hereinafter, referred to as “the small-diameter ejection port H2505”). , Is referred to as “uniformity”) is more likely to occur than the large-diameter discharge port H2504. As described above, the small-diameter discharge port H2505, which has poor uniformity compared to the large-diameter discharge port H2504, has a smaller discharge port diameter in order to further reduce the size of the droplets or is left for a long time to evaporate the solvent. When ink having a high viscosity is ejected, it tends to be further deteriorated.

  Next, how the configuration of the present embodiment shown in FIG. 11A improves such uniformity is described.

  In the recording head H1001 shown in FIG. 11A, the ink supplied from the common liquid chamber H1102 is filled in the first ink flow path H2501 and the second ink flow path H2502, respectively. When the electrothermal conversion element H1103 (see FIGS. 4 and 5) in each ink channel is driven, large and small ink droplets are ejected from the large-diameter ejection port H2504 and the small-diameter ejection port H2505, respectively.

  Here, when a large droplet is ejected from the large-diameter ejection port H2504, the ink is supplied (refilled) again to the first ink flow path H2501 by the amount of the ejected ink liquid. Most of the ink is supplied from the common liquid chamber H1102, but in this embodiment, the first ink flow path H2501 communicates with the adjacent second ink flow path H2502 via the third ink flow path H2503. Part of the refilled ink is supplied to the first ink flow path H2501 through the third ink flow path H2503 also from the second ink flow path H2502 on both sides thereof. As a result, even if the small-diameter ejection port H2505 itself does not eject an ink droplet, if an ink droplet is ejected from the adjacent large-diameter ejection port H2504, an ink flow is generated in the second ink flow path H2502. In particular, by disposing the first ink flow path H2501 on both sides of the second ink flow path H2502, if ink droplets are ejected from the large-diameter ejection port H2504 of at least one of the first ink flow paths H2501, An ink flow is generated in the two ink flow path H2502.

  Thus, by causing the ink flow in the second ink flow path H2502, the ink solvent in the second ink flow path H2502 can be obtained even when ink droplets are not ejected from the small-diameter ejection port H2505 for a long time. As a result, it is possible to suppress the increase in viscosity due to vaporization, so that it is possible to improve the uniformity of the small-diameter discharge port H2505. Furthermore, even if the discharge port diameter of the small-diameter discharge port H2505 is further reduced in order to further reduce the droplet size, it is possible to prevent deterioration of the uniformity.

  The third ink flow path H2503 has a larger cross-sectional area on the second ink flow path H2502 side than the first ink flow path H2501 side, and the cross-sectional area gradually decreases toward the first ink flow path H2501 side. Has a tapered shape. As described above, by reducing the cross-sectional area of the third ink flow path H2503 on the first ink flow path H2501 side, bubbles are generated in the first ink flow path H2501 in order to eject ink droplets. The vibration (pressure wave) is hardly transmitted to the second ink flow path H2502 through the third ink flow path H2503. Conversely, since the cross-sectional area of the third ink flow path H2503 on the second ink flow path H2502 side is large, ink passes from the second ink flow path H2502 through the third ink flow path H2503 to the first ink flow path. Smoothly flows into H2501. Accordingly, ink is supplied from the common liquid chamber H1102 into the second ink flow path H2502, so that an ink flow occurs in the second ink flow path H2502.

  FIG. 12 is a diagram showing the channel widths of the first ink channel H2501, the second ink channel H2502, and the third ink channel H2503 in the recording head H1001 having the configuration shown in FIG. 11A. In the drawing, W1 indicates the channel width of the second ink channel H2502, and in this embodiment, the channel width is 28 μm. W2 indicates the channel width of the first ink channel H2501, and in this embodiment, the channel width is 32 μm. W3 indicates the flow path width of the third ink flow path H2503, and the detailed dimensions thereof are not specified here, but the flow path width is larger than both the first and second ink flow paths H2501 and H2502. It is narrow and is set so that the second ink flow path H2502 side is wider than the first ink flow path H2501 side. The height of each ink flow path is 14 μm.

  As described above, when a large droplet is ejected from the large-diameter ejection port H2504, the ink refill to the first ink flow path H2501 is performed in addition to the ink supplied from the common liquid chamber H1102 and the second neighboring ink. This is performed by ink supplied from the second ink flow path H2502 through the third ink flow path H2503.

  In the configuration of the present embodiment, the second ink flow path H2502 and the third ink flow path H2503 are narrower than the first ink flow path H2501, and the second ink flow path H2502 and the third ink flow path. Since the sum of the channel lengths with the channel H2503 is longer than the channel length of the first ink channel H2501, the sum of the flow resistances of the second ink channel H2502 and the third ink channel H2503 is It is larger than the flow resistance of the first ink flow path H2501. By providing the flow resistance difference in this way, the pressure generated when bubbles are bubbled in the first ink flow path H2501 hardly escapes to the third ink flow path H2503 side. Even if one ink flow path H2501 communicates with the second ink flow path H2502 via the third ink flow path H2503, there is no particular effect on the ejection of ink droplets from the large-diameter ejection port H2504. .

  FIG. 11B is a diagram showing a modification of the recording head shown in FIG. 11A. As shown in FIG. 11B, in the configuration in which the third ink flow path H2503 is not parallel to the extension direction of the common liquid chamber H1102 but is inclined obliquely, the length of the third ink flow path H2503 is compared to the configuration in FIG. 11A. Become longer. In such a configuration, the flow width of the third ink flow path H2503 is made wider than that of the third ink flow path H2503 shown in FIG. It can be equivalent to the structure shown in FIG. Accordingly, in the configuration shown in FIG. 11B as well, as in the configuration shown in FIG. 11A, the first ink flow from the second ink flow path H2502 through the third ink flow path H2503 during refilling to the first ink flow path H2501. Since ink is supplied into the path H2501, an ink flow can be generated in the second ink flow path H2502.

  Referring to FIG. 11A again, the first ink flow path H2501 and the second ink flow path H2502 face each other with the common liquid chamber H1102 interposed therebetween. The distance between the first ink flow paths H2501 and the distance between the second ink flow paths H2502 in the first ink flow path row are 300 dpi, respectively. The distance between the first ink flow path H2501 and the second ink flow path H2502 is as follows. 600 dpi. The positional relationship between the ejection ports H2504 and H2505 facing each other across the common liquid chamber H1102 in the first ink channel row and the second ink channel row is the first of the first ink channel row. The center of the large-diameter ejection port H2504 of the ink channel H2501 and the center of the small-diameter ejection port H2504 of the second ink channel H2502 of the second ink channel array facing the common liquid chamber H1102 in between. The first ink flow channel row and the second ink flow channel row have a relationship of being arranged on the same straight line in a direction orthogonal to the arrangement direction of the ink flow channel rows. The outlet H2505 is staggered. In other words, the first ink flow channel rows are arranged in a direction perpendicular to the arrangement direction of the ink flow channel rows with respect to the second ink flow channel rows arranged in parallel with the common liquid chamber H1102 interposed therebetween. The first ink flow path H2501 and the second ink flow path H2502 are arranged to face each other. When the ejection ports H2504 and H2505 are arranged in this manner, a carriage (not shown) on which the recording head H1001 is mounted is scanned in the recording apparatus in a direction orthogonal to the arrangement direction of the ink flow path rows in FIG. 11A. In addition, ink droplets can be ejected at a resolution of 600 dpi for both the large-diameter ejection port H2504 and the small-diameter ejection port H2505.

  In this embodiment, in each ink flow path row, the first ink flow paths H2501 and the second ink flow paths H2502 are arranged at an interval of 300 dpi, and the first ink flow path H2501 and the second ink flow path H2502 are arranged. Are arranged at intervals of 600 dpi, but it is also possible to further improve the recording resolution of the recording head H1001 by setting these intervals narrower.

  In the configuration shown in FIGS. 11A and 11B, the large-diameter ejection ports H2504 and the small-diameter ejection ports H2505 are alternately arranged in the arrangement direction of the respective ink flow path rows, and the large-diameter ejection ports H2504 and the small-diameter ejection ports H2505 are arranged. Are arranged on the same straight line in the arrangement direction of the respective ink flow path rows, but as in the other modification shown in FIG. It is also possible to adopt a configuration in which the arrangement consisting of only H2504 and the arrangement consisting only of the small-diameter discharge port H2505 are shifted from each other.

  As described above, in a configuration in which the arrangement composed only of the large-diameter ejection openings H2504 and the arrangement composed only of the small-diameter ejection openings H2505 are shifted from each other in the arrangement direction of the respective ink flow path arrays, The vibration generated when the ink liquid is discharged from each of the ink droplets through the third ink flow path H2503 is less likely to be directly transmitted to the vicinity of the discharge openings of the ink flow paths adjacent to each other, so that the ink droplet discharge operation is performed more stably. It becomes possible.

  In this configuration, the communication portion of the third ink flow path H2503 with the second ink flow path H2502 is at the same position as the small-diameter ejection port H2505 in the extending direction of the second ink flow path H2502 or farther from the common liquid chamber H1102. It is located at the position. As a result, when the ink is refilled into the first ink flow path H2501 as described above, the ink in the vicinity of the small-diameter ejection port H2505 in the second ink flow path H2502 passes through the third ink flow path H2503 to the first. The ink is supplied into the ink flow path H2501. Note that the communication portion of the third ink flow path H2503 with the first ink flow path H2501 is further away from the common liquid chamber H1102 than the large-diameter ejection port H2504 in the extending direction of the first ink flow path H2501 as shown in FIG. 11A. Or may be located at the same position as the large-diameter ejection port H2504 in the extending direction of the first ink flow path H2501 as shown in FIG. 11B.

  FIG. 13A is a diagram showing a modification of the recording head shown in FIG. 11A, FIG. 13B is a diagram showing a modification of the recording head shown in FIG. 11B, and FIG. 13C is a modification of the recording head shown in FIG. It is a figure which shows an example. In each modification shown in FIGS. 13A to 13C, unlike the configuration shown in FIGS. 11A to 11C, each second ink flow path H2502 is third only to the first ink flow path H2501 adjacent to a predetermined one side. It is configured to communicate with each other via an ink flow path H2503. Other configurations of the modified examples illustrated in FIGS. 13A to 13C are the same as the corresponding configurations illustrated in FIGS. 11A to 11C.

  13A to 13C, ink droplets are ejected from the large-diameter ejection port H2504 of the first ink channel H2501 in which the second ink channel H2502 communicates with the third ink channel H2503. At this time, since the ink in the second ink flow path H2502 passes through the third ink flow path H2503 and is refilled into the first ink flow path H2501, it is long from the small-diameter ejection port H2505 of the second ink flow path H2502. Even in a case where ink is not ejected over time, it is possible to prevent the ink in the second ink flow path H2502 from being thickened and impairing the uniformity.

  According to the configuration of the present embodiment as described above, ink droplets are ejected from the large-diameter ejection port H2504 that is used relatively frequently even when ink is not ejected from the small-diameter ejection port H2505 for a long time. Then, when ink is refilled into the first ink flow path H2501, the ink in the second ink flow path H2502 is supplied into the first ink flow path H2501 through the third ink flow path H2503. . As a result, an ink flow is generated in the second ink flow path H2502, so that the ink filled in the second ink flow path H2502 can be maintained in a fresh state. It is possible to improve the uniformity in discharging. For this reason, it is not necessary to perform preliminary ejection before the recording operation of the recording head or to heat and keep the recording head heated, so that the throughput of the recording operation by the recording head can be improved.

  Note that a recording element (corresponding to the electrothermal conversion element H1103 shown in FIGS. 4 and 5 in the present embodiment) disposed corresponding to the large-diameter ejection port H2504 of the recording head H1001 and a small-diameter ejection port H2505 are disposed. When the recording elements are not driven at the same time because some of the signal lines connected to them are shared (that is, the recording head H1001 has a large-diameter ejection port H2504). The first ink flow path H2501 and the second ink flow path according to the configuration of the present embodiment, even in the case of a configuration having only a discharge mode only from the small-diameter discharge port H2505). Since H2502 communicates with the third ink flow path H2503, the inlet of the second ink flow path H2502 (the end on the common liquid chamber H1102 side) is temporarily clogged with dust or the like. However, it is possible to supply ink into the second ink flow path H2502 via the first ink flow path H2501 and the third ink flow path H2503, and it is possible to discharge ink droplets from the small diameter discharge port H2505. . This means that the reliability of a recording head that employs the driving method described above can be improved.

  In the configuration of this embodiment, filters may be provided at the ends of the first and second ink flow paths H2501 and H2502 on the common liquid chamber H1102 side, and the diameters of these filters are the discharge sizes provided in the respective ink flow paths. It is preferable that the diameter is the same as or slightly smaller than the diameter of the outlets H2504 and H2505. In this case, since the diameter of the filter provided in the second ink flow path H2502 is smaller than the diameter of the filter provided in the first ink flow path H2501, depending on the size, the diameter of the filter to the second ink flow path H2502 through the filter is increased. There is a possibility that the refilling speed of the machine becomes slow. However, even if the refill speed from the end portion of the second ink flow path H2502 becomes slow, the ink remains in the second ink flow path H2502 through the first ink flow path H2501 and the third ink flow path H2503. Since it is supplied, it is possible to suppress the influence slightly.

FIG. 2 is a perspective view showing a recording head cartridge in one embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating a configuration of the recording head illustrated in FIG. 1. FIG. 3 is an exploded perspective view illustrating a state in which the recording head illustrated in FIG. 2 is further finely disassembled. 1 is a perspective view showing a configuration of a recording element substrate in an embodiment of the present invention with a part cut away. FIG. 6 is a perspective view showing a configuration of another recording element substrate in an embodiment of the present invention with a part cut away. FIG. 3 is a cross-sectional view of a main part of a recording head cartridge according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a main part of a recording element unit according to an embodiment of the present invention in an exploded state. FIG. 3 is a cross-sectional view schematically showing a main part of a recording element unit according to an embodiment of the present invention. FIG. 2 is a perspective view showing a recording element unit and an ink supply unit assembled in an embodiment of the present invention. FIG. 2 is a perspective view illustrating a bottom surface side of a recording head according to an embodiment of the invention. FIG. 3 is an enlarged cross-sectional view of a main part of a recording element unit according to an embodiment of the present invention. FIG. 3 is a plan view illustrating a discharge port forming surface of a recording head according to an embodiment of the invention. FIG. 6 is a plan view showing an ejection port forming surface of a modified example of the recording head according to the embodiment of the invention. FIG. 10 is a plan view illustrating an ejection port forming surface of another modification of the recording head according to the embodiment of the invention. It is a figure which shows the channel width of the 1st ink flow path, the 2nd ink flow path, and the 3rd ink flow path in the recording head of the structure shown to FIG. 11A. FIG. 11B is a plan view showing a discharge port forming surface of a modified example of the recording head shown in FIG. 11A. FIG. 11B is a plan view showing a discharge port forming surface of a modification of the recording head shown in FIG. 11B. FIG. 11D is a plan view showing a discharge port forming surface of a modification of the recording head shown in FIG. 11C. FIG. 10 is a plan view illustrating a discharge port forming surface of a conventional recording head. It is a top view which shows the discharge port formation surface of the other conventional recording head.

Explanation of symbols

H1102 Common liquid chamber H1103 Electrothermal conversion element H2501 First ink flow path H2502 Second ink flow path H2503 Third ink flow path H2504 Large diameter discharge port H2505 Small diameter discharge port

Claims (4)

A plurality of ejection ports that eject ink, and a plurality of recording elements that are provided corresponding to each of the plurality of ejection ports and that generate energy used to eject the ink from the plurality of ejection ports; A plurality of ink flow paths communicating with the plurality of ejection ports and corresponding to the plurality of recording elements, and a common liquid chamber for supplying the ink to the plurality of ink flow paths,
The plurality of ink flow paths include a first ink flow path communicating with a relatively large diameter discharge port and a second ink flow path communicating with a relatively small diameter discharge port. In the inkjet recording head, wherein the path and the second ink flow path are alternately arranged so as to be adjacent to each other,
A third ink channel that connects the first ink channel and the second ink channel to each other ;
The first and second ink flow paths each extend in a direction perpendicular to the arrangement direction of the ink flow path rows,
The communication portion of the third ink flow path with the second ink flow path is the same position as the relatively small-diameter discharge port in the extending direction of the second ink flow path or further away from the common liquid chamber. Inkjet recording head located in position. A plurality of ejection ports that eject ink, and a plurality of recording elements that are provided corresponding to each of the plurality of ejection ports and that generate energy used to eject the ink from the plurality of ejection ports; A plurality of ink flow paths communicating with the plurality of ejection ports and corresponding to the plurality of recording elements, and a common liquid chamber for supplying the ink to the plurality of ink flow paths,
  The plurality of ink flow paths include a first ink flow path communicating with a relatively large diameter discharge port and a second ink flow path communicating with a relatively small diameter discharge port. In the inkjet recording head, wherein the path and the second ink flow path are alternately arranged so as to be adjacent to each other,
  A third ink channel that connects the first ink channel and the second ink channel to each other;
  An ink jet recording head, wherein a sum of flow resistances of the second ink flow path and the third ink flow path is larger than a flow resistance of the first ink flow path. A plurality of ejection ports that eject ink, and a plurality of recording elements that are provided corresponding to each of the plurality of ejection ports and that generate energy used to eject the ink from the plurality of ejection ports; A plurality of ink flow paths communicating with the plurality of ejection ports and corresponding to the plurality of recording elements, and a common liquid chamber for supplying the ink to the plurality of ink flow paths,
  The plurality of ink flow paths include a first ink flow path communicating with a relatively large diameter discharge port and a second ink flow path communicating with a relatively small diameter discharge port. In the inkjet recording head, wherein the path and the second ink flow path are alternately arranged so as to be adjacent to each other,
  A third ink channel that connects the first ink channel and the second ink channel to each other;
  The ink jet recording head, wherein the third ink flow path has a shape in which a cross-sectional area gradually decreases from a communication portion with the second ink flow path toward a communication portion with the first ink flow path. A plurality of ejection ports that eject ink, and a plurality of recording elements that are provided corresponding to each of the plurality of ejection ports and that generate energy used to eject the ink from the plurality of ejection ports; A plurality of ink flow paths communicating with the plurality of ejection ports and corresponding to the plurality of recording elements, and a common liquid chamber for supplying the ink to the plurality of ink flow paths,
  The plurality of ink flow paths include a first ink flow path communicating with a relatively large diameter discharge port and a second ink flow path communicating with a relatively small diameter discharge port. In the inkjet recording head, wherein the path and the second ink flow path are alternately arranged so as to be adjacent to each other,
  A third ink channel that connects the first ink channel and the second ink channel to each other;
  The ink jet recording head, wherein the second ink flow path communicates with the first ink flow path adjacent to a predetermined one side of the second ink flow path via the third ink flow path.

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