JP2007030453A - Inkjet recording head and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head and an inkjet recorder, which suppress adhesion and amalgamation of ink mist to the vicinity of a discharge port, and hardly cause discharge failure even when a secondary color print is formed. <P>SOLUTION: In the inkjet recording head, a plurality of discharge port arrays H1108 are formed in a discharge port forming surface A, and a water repellent area B surrounding an area provided with a discharge port array H1108 is individually provided on every discharge port array 1108. There are also provided: a plurality of first hydrophilic areas C1 which are arranged adjacent to the water repellent areas B, extend in a discharge array direction, and individually provided; and a second hydrophilic area C2 which is mutually adjacent to the water repellent areas B and extends in a direction orthogonal to the discharge port arrays, and the first hydrophilic areas C1 and the second hydrophilic area C2 are connected to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet recording head having an ejection port for ejecting ink and an inkjet recording apparatus using the inkjet recording head.

In recent years, the demand for high gradation color printing has increased due to the spread of the Internet and digital cameras, and the performance of ink jet printers is being improved accordingly. The following methods are known as means for obtaining a high-definition and high-gradation high-quality print image.
(1) The arrangement interval of the ejection ports for ejecting ink is narrowed to improve the resolution.
(2) For a specific color ink, prepare a plurality of ink jet recording heads that respectively eject a plurality (at least two) of color inks having different ratios of the colorant contained in the color ink, that is, the concentration of the colorant. Accordingly, the gradation is improved by selectively overprinting dark ink and light ink.
(3) Tonality is improved by varying the size of the ink droplets ejected from the ejection ports, that is, the ink amount.

  In a so-called ink jet printer that uses thermal energy as discharge energy for discharging ink from the discharge port of the ink jet recording head, generates bubbles in the ink, and uses the foaming pressure at that time, the above-described (3 The method (1) or (2) is considered to be particularly effective.

  However, if the method (2) is to be realized, two or more ink jet recording heads are required for a specific color ink, resulting in an increase in cost. Therefore, in the ink jet printer, as shown in (1), the arrangement interval of the ejection ports is narrowed, and the size of each ink droplet ejected from each ejection port is reduced (for example, 10 picoliters or less). The improvement method is the most desirable and simple method because it hardly increases the manufacturing cost.

  In the case where such small ink droplets are ejected from the ejection port, Patent Documents 1 to 3 disclose a system in which bubbles that grow due to film boiling as the ink is heated communicate with the atmosphere via the ejection port. Yes.

  In an ink jet recording head based on the conventional ink jet method that discharges ink droplets without allowing bubbles that grow due to film boiling to communicate with the atmosphere, the ink droplets communicate with the discharge ports as the size of the ink droplets discharged from the discharge ports decreases. The passage cross-sectional area of the ink flow path must be reduced, resulting in a problem that the discharge efficiency is lowered and the discharge speed of ink droplets discharged from the discharge ports is reduced. When the discharge speed of ink droplets decreases, the discharge direction becomes unstable, and the ink becomes thicker as the water vapor evaporates when the inkjet recording head is stopped. Defects may occur and reliability may be reduced.

  In this respect, the ink jet recording head of the ejection method in which bubbles communicate with the atmosphere is suitable for ejecting small ink droplets because the size of the ink droplet can be determined only by the geometric shape of the ejection port, such as temperature It has the advantage that it is less susceptible to the effects of ink droplets and the amount of ink droplets ejected is very stable compared to conventional inkjet recording heads, so it is relatively easy to produce high-definition and high-gradation high-quality printed images. It is possible to get to.

  In order to obtain a high-definition and high-gradation high-quality print image, it is preferable to perform printing by ejecting an extremely small amount of ink droplets from one ejection port. In this case, in order to increase the printing speed, it is necessary to eject ink droplets from the ejection ports in a short cycle. In addition, the carriage on which the inkjet recording head is mounted must be scanned and moved at high speed with respect to the print medium in synchronization with the drive frequency of the inkjet recording head. From such a viewpoint, it can be said that an ink jet printer is particularly suitable for a discharge type in which bubbles communicate with the atmosphere.

  However, when recording is actually executed, there is a case in which minute ink flying from the ejection port after the main ink droplet is generated along with the main ink droplet ejected in response to the recording signal. In addition, when the main ink droplets land on the recording paper, a phenomenon that the ink bounces upon landing may occur, and very fine ink droplets may be generated in the recording area. When such minute ink (hereinafter sometimes referred to as ink droplets) is generated, it often adheres to the ejection opening surface of the ink jet recording head and causes ink pooling. It is known that the occurrence of such a liquid pool leads to the occurrence of problems such as unstable ejection of ink droplets from the ejection port and non-ejection of ink.

  In order to solve such a problem, the water repellent treatment is performed on the discharge port surface 6 provided with the discharge ports 4 shown in FIG. 17 (a discharge port array including a plurality of discharge ports 4 may be referred to as a discharge port H1108). Was done. Conventionally, the water repellent film has been formed on almost the entire surface of the discharge port formation surface.

  When the water-repellent film is formed on almost the entire surface of the ejection port as described above, the ink stays in the peripheral portion of the ejection port and the above-mentioned problems such as unstable ejection of the ink are improved to some extent. However, when a plurality of colors are driven at the same time to perform continuous long-term, high-frequency driving, high printing speed, and high duty, the amount of ink mist generated is large, and the discharge port surface As a result, ink droplets gradually accumulate.

  Hereinafter, how the ink mist adhering to the ejection port surface changes the ink ejection state will be briefly described.

  A secondary color print that continuously ejects ink droplets from a half ejection port and simultaneously ejects a plurality of chips on the print medium while moving such an inkjet recording head along with the carriage at high speed along the print medium. FIG. 18 shows the ink droplet ejection state at this time. FIGS. 19A to 19D show changes over time in the ejection state of ink droplets 10 of the ejection method in which bubbles communicate with the atmosphere. As time passes, the main droplet 11 and a plurality of minute satellite counties 12 are separated. The scanning movement direction of the recording head is a direction as indicated by an arrow with respect to the paper surface of FIG. 18, and the ejection ports H1108 are arranged in the direction shown in FIG. When the image data has a high duty, an ejection energy generation unit (not shown) corresponding to each ejection port of each chip forming the secondary color is driven at a high driving frequency. For this reason, along with the movement of the ink droplet 10 ejected from the ejection port toward the print medium 3, the viscous air existing around the ink droplet 10 is moved by the movement of the ink droplet 10. As a result, the vicinity of the ejection port surface where the ejection port of the recording head H1001 opens tends to be decompressed more than the surroundings of the print medium 3, and the surrounding air flows as an air stream to the decompression region. A satellite (not shown) discharged along with the ink droplets 10 in the vicinity of 3 and a droplet group smaller than the main droplet of the bounce mist generated when the ink droplets 10 land on the print medium 3 are on the recording head H1001 side. Turned out to be attracted to.

  Under such a phenomenon, when high duty printing is performed by scanning movement of the carriage a plurality of times, a state in which mist adheres to the face surface of the recording head H1001 at this time is shown in FIG. This is schematically shown in (b).

  When FIG. 20A is only a primary color, FIG. 20B is a mist adhesion diagram when a secondary color is used. Compared to the size of ink droplets attached to the ejection port surface (ink droplets indicated by a in the figure) in the case of only the primary color shown in FIG. The size of the ink (ink droplets indicated by b in the figure) is considerably large. In the case of the secondary color, ink droplets are ejected at a high frequency on both sides in the area between the chips, so that the pressure tends to be further reduced as compared with the case of the primary color, and satellites and bounce mist are generated in the recording head H1001. In addition to the large size of the ink droplets, the amount of ink droplets adhering is large.

  In addition, as a result of studies by the inventors, it has been found that ink mist tends to gradually adhere to a region away from the discharge port in a configuration in which water repellent treatment is performed on almost the entire surface of the nozzle. For example, in a region about 500 μm to 1 mm away from the discharge port, there are a large number of ink mist aggregates that have grown to a large diameter of about 300 μm to 500 μm. In the water-repellent region, since the contact angle with water (ink) is large, the fluidity is large (when the contact angle with water exceeds 80 degrees, it becomes more remarkable). In particular, in the case of an apparatus configuration in which the recording head itself reciprocates the area where recording is performed, it starts to move easily by the inertial force generated by the reciprocating motion or by its own weight, and finally reaches the discharge port. The ink mist that has grown to a certain extent is drawn into the discharge ports of one to several nozzles that partially correspond to cause a non-discharge phenomenon.

Furthermore, in order to prevent ink mist from adhering to the nozzle formation surface and moving these to the discharge port side and being drawn into the discharge port and causing non-discharge, a part of the hydrophilic area is provided near the discharge port array, Means for temporarily holding ink mist and stabilizing ejection have been put into practical use. Patent Document 4 discloses a configuration in which a water repellent treatment 6 is performed in each chip on the nozzle forming surface and a hydrophilic treatment 5 is performed between the chips as shown in FIG. In the configuration in which a part of the nozzle forming surface is subjected to hydrophilic treatment, the ink mist is moved and held in the hydrophilic region between the chips, and the growth of the ink mist adhered between the chips is suppressed. There is no phenomenon that is partially drawn into the corresponding one to several nozzles and causes no discharge.
Japanese Patent Laid-Open No. 4-10940 JP-A-4-10941 JP-A-4-10742 JP-A-6-12210

  However, in recent color ink jet recording heads, it is difficult to secure a sufficient hydrophilic region width W when the distance between the chips is reduced due to high density and miniaturization. For this reason, when performing secondary color printing for simultaneously ejecting a plurality of chips on a print medium, ink mist is ejected at a high frequency on both sides in the area between the chips. The pressure tends to be reduced, and the ink and the ink mist composed of the bounce mist tend to be conspicuously gathered in the hydrophilic region. For this reason, there is a problem that a large amount of ink mist adheres to the hydrophilic region and the ink overflows from the hydrophilic region between the chips. Due to the overflow caused by such factors, the ink mist enters the water-repellent area on the ejection port side, and the combined and grown ink mist is partially drawn into the corresponding one or several nozzles and becomes non-ejection. There is a case.

  For this reason, the hydrophilic region width W between the chips has to be arranged with a certain distance, and there is a problem in that there is a limit in increasing the density and size of the recording head.

  As a method for solving these problems, a method of increasing the frequency of cleaning the discharge port forming surface, for example, from one page unit to one line unit is conceivable. However, there is a problem that increasing the number of cleanings causes a decrease in printing speed.

  Such a problem is particularly caused in an ink jet printer of a discharge type in which bubbles are arranged so that a small interval of ink droplets of 10 picoliters or less can be discharged at a high cycle by one driving operation with a narrow arrangement interval of discharge ports. Appears prominently.

  An object of the present invention is a satellite that is ejected from an ejection port even in an ejection type ink jet printer in which bubbles that can eject a small amount of ink droplets of 10 picoliters or less at a high cycle by a single driving operation communicate with the atmosphere. To provide an ink jet recording head and an ink jet recording apparatus in which ink droplets / bounce mist are prevented from adhering to and coalesced in the vicinity of an ejection port in an ink jet recording head, and even when a secondary color print is formed, ejection defects are less likely to occur. is there.

  In order to solve the above-described problems, the present invention provides an inkjet head in which a plurality of ejection port arrays configured of a plurality of ejection ports for ejecting ink are arranged on an ejection port formation surface. A plurality of first hydrophilic regions that are provided adjacent to the water-repellent region and that extend separately in the direction of the discharge port array and have water-repellent regions surrounding the provided region individually And a water-repellent region and a second hydrophilic region extending in a direction orthogonal to the ejection port array and adjacent to each other, wherein the first hydrophilic region and the second hydrophilic region are connected to each other. And

  According to the present invention, during the secondary color printing, a large amount of ink gathers in the first hydrophilic area and moves and merges, but the first hydrophilic area and the second hydrophilic area are connected, so the first hydrophilic area is connected. The ink mist that overflows the hydrophilic region flows to the second hydrophilic region, and can be captured by the second hydrophilic region. Therefore, the ink mist does not enter the water-repellent area on the discharge port side, and the combined and grown ink mist is partially drawn into the discharge ports of one to several nozzles corresponding to the ink mist and does not cause non-discharge.

Example 1
Next, embodiments of the present invention will be described with reference to the drawings.

  FIGS. 1 to 7 are diagrams for explaining the configuration of each of the preferred head cartridge, recording head, and ink tongue to which the present invention is applied or applied, and the relationship between them. Hereinafter, each component will be described with reference to these drawings.

  As can be seen from the perspective view of FIG. 1, the recording head H1001 of the present invention is one constituent element of the recording head cartridge H1000. The recording head cartridge H1000 includes the recording head H1001 and the recording head as shown in FIG. The ink tank H1900 (H1901, H1902) is detachably provided on the H1001. The recording head cartridge H1000 is fixedly supported by positioning means and electrical contacts of a carriage 16 (FIG. 4) mounted on the ink jet recording apparatus main body, and is detachable from the carriage 16. The ink tank H1901 is for black ink, and the ink tank H1902 is for cyan, magenta, and yellow ink. In this way, each of the ink tanks H1901 and H1902 is detachable from the recording head H1001.

Next, the recording head H1001 will be described in detail for each component constituting the recording head.
(1) Recording Head The recording head H1001 is an ink-jet side shooter type that performs recording using an electrothermal transducer that generates thermal energy for causing film boiling to the ink in response to an electrical signal. It is a recording head.

As shown in the exploded perspective view of FIG. 1, the recording head H1001 includes a recording element unit H1002, a first recording element substrate H1100, a second recording element substrate H1101, a first plate H1200, an electric wiring tape H1300, and an electrical wiring tape H1300. The ink supply unit includes an ink supply member H1500, a flow path forming member (not shown), a joint seal member H2300, a filter (not shown), a seal rubber (not shown). (Illustrated).
(1-1) Recording Element Unit FIG. 2 is a partially exploded perspective view for explaining the configuration of the first recording element substrate H1100. The first recording element substrate H1100 is anisotropically etched using, for example, a Si substrate H1110 having a thickness of 0.5 to 1 mm and an ink supply port H1102 having a long groove-like through-hole as an ink channel using the crystal orientation of Si. The electrothermal conversion elements H1103 are arranged in a staggered pattern on both sides of the ink supply port H1102, and power is supplied to the electrothermal conversion elements H1103 and the electrothermal conversion elements H1103. The electrical wiring such as Al is formed by a film forming technique. Furthermore, electrode portions H1104 for supplying power to the electrical wiring are arranged on both outer sides of the electrothermal transducer H1103, and bumps H1105 such as Au are formed on the electrode portion H1104. On the Si substrate, 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. Forming. Accordingly, since the ejection port is provided to face the electrothermal conversion element H1103, the ink supplied from the ink flow path H1102 is ejected by bubbles generated by the electrothermal conversion element H1103.

  FIG. 3 is a partially exploded perspective view for explaining 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 has three ink supply ports H1102 formed in parallel, and electric is provided on both sides of each ink supply port. A heat conversion element and an ink discharge port are formed. Of course, like the first recording element substrate H1100, an ink supply port, an electrothermal conversion element, an electric wiring, an electrode portion, and the like are formed on the Si substrate, and an ink flow path and an ink are formed on the resin material by photolithography. A discharge port is formed.

  Similarly to the first recording element substrate H1100, a bump H1105 such as Au is formed on the electrode portion H1104 for supplying power to the electrical wiring.

Next, the first plate H1200 is made of, for example, an alumina (Al ₂ O ₃ ) material having a thickness of 0.5 to 10 mm. The material of the first plate is not limited to alumina, and has a linear expansion coefficient equivalent to that 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. Alternatively, it may be made of a material having an equivalent or higher thermal conductivity. Examples of the material of the first plate H1200 include silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). Either may be sufficient. The first plate H1200 has ink supply ports H1201 for supplying black ink to the first recording element substrate H1100 and inks for supplying cyan, magenta, and yellow ink to the second recording element substrate H1101. A supply port H1201 is formed, the ink supply port 1102 of the recording element substrate corresponds to the ink supply port H1201 of the first plate H1200, and 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 H1202 used for 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 H1202 is, for example, a thermosetting adhesive mainly composed of an epoxy resin, and the thickness of the adhesive layer is desirably 50 μm or less.

  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, and includes a plurality of recording element substrates. An electrical contact substrate having an opening, an electrode terminal H1302 corresponding to the electrode portion H1104 of each recording element substrate, and an external signal input terminal H1301 located at the end of the wiring tape for receiving an electrical signal from the main unit An electrode terminal portion H1303 for electrical connection with H2200 is provided, and the electrode terminal H1302 and the electrode terminal 1303 are connected by a continuous copper foil wiring pattern.

  The electrical wiring tape H1300, the first recording element substrate 1100, and the second recording element substrate H1101 are electrically connected to each other, and the connection method is, for example, the electrode portion 1104 of the recording element substrate and the electrical wiring tape H1300. The electrode terminal H1302 is electrically bonded by a thermal ultrasonic pressure 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.

  The first recording element substrate H1100 and the second recording element substrate H1101 that are bonded and fixed to the first plate H1200 have openings that are larger than the outer dimensions thereof. Further, the first recording element substrate H1100 and the second recording element substrate H1101 and the electric wiring tape H1300 are bonded to the first plate H1200 with a second adhesive H1203 so as to be electrically connected in a plane. The back surface of the wiring tape H1300 is bonded and fixed with a third adhesive H1306.

  The first recording element substrate H1100, the second recording element substrate H1101, and the electrical connection portion of the electrical wiring tape H1300 are sealed 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 sealing agent mainly seals the back surface side of the connection portion between the electrode terminal H1302 of the electric wiring tape and the electrode portion H1105 of the recording element substrate and the outer peripheral portion of the recording element substrate, and the second sealing agent. Has sealed the front side of the connection part.

Further, an electrical contact substrate H2200 having an external signal input terminal H1301 for receiving an electrical signal from the main unit is connected to the end of the electrical wiring tape by thermocompression bonding using an anisotropic conductive film or the like and The electric wiring tape H1300 is bent on one side surface of the first plate H1200, and is bonded to the side surface of the first plate H1200 with a third adhesive (not shown). As the third adhesive, for example, a thermosetting adhesive having a thickness of 10 to 100 μm mainly composed of an epoxy resin is used.
(1-2) Ink Supply Unit 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 FIG. 5, the ink supply member H1500 is one component of the ink supply unit H1003 for guiding ink from the ink tank H1900 to the recording element unit H1002, and the flow path forming member (not shown) is ultrasonically welded. By doing so, an ink flow path (not shown) is formed. In addition, a filter (not shown) for preventing entry of dust from the outside is joined to the joint engaged with the ink tank H1900 by welding, and further, in order to prevent ink from evaporating from the joint portion. A seal rubber (not shown) is attached.
(2) Inkjet recording apparatus FIG. 4 shows the appearance of the mechanism part of the ink jet printer in this embodiment, FIG. 5 shows the appearance of the head cartridge used in this ink jet printer, and FIG. 6 shows the appearance of the ink jet recording head. . That is, the chassis 13 of the ink jet printer in the present embodiment is composed of a plurality of plate-like metal members having a predetermined rigidity, and forms the skeleton of the ink jet printer. For the chassis 13, a medium feeding unit 14 that automatically feeds a sheet-like print medium (not shown) to the inside of the ink jet printer, and a print medium fed one by one from the medium feeding unit 14 are desired. A medium transport section 16 that guides the print medium from the print position to the medium discharge section 15, a print section that performs a predetermined print operation on the print medium transported to the print position, and a print section for the print section. A head recovery unit 17 that performs recovery processing is assembled.

  The printing unit includes a carriage 19 supported so as to be movable along the carriage shaft 18 and a recording head cartridge H1000 that is detachably mounted on the carriage 19 via a head set lever 20.

  The carriage 19 on which the recording head cartridge H1000 is mounted has a carriage cover 21 for positioning the recording head H1001 of the recording head cartridge H1000 at a predetermined mounting position on the carriage 19, and the recording head H1001 at a predetermined mounting position. The above-described headset lever 20 is provided to press the positioning lever. The head set lever 20 as the attaching / detaching means of the present invention is provided on the upper portion of the carriage 19 so as to be rotatable with respect to a head set lever shaft (not shown), and the engaging portion with the recording head H1001 is spring-biased. A head set plate (not shown) is provided, and is mounted on the carriage 19 while pressing the recording head H1001 by the spring force of the head set plate.

  One end portion of a contact flexible printed cable (hereinafter referred to as a contact FPC) 22 is connected to another engagement portion of the carriage 19 with respect to the recording head H1001, and a contact portion (not shown) formed at one end portion of the contact FPC 22 The contact portion 23 which is an external signal input terminal provided in the recording head 2H1001 is in electrical contact, and can exchange various information for printing and supply power to the recording head H1001. Yes.

  An elastic member such as rubber (not shown) is provided between the contact portion of the contact FPC 22 and the carriage 19, and the contact portion of the contact FPC 22 and the recording head H1001 are formed by the elastic force of the elastic member and the pressing force by the headset plate. The contact portion 23 can be reliably contacted. The other end of the contact FPC 22 is connected to a carriage substrate (not shown) mounted on the back surface of the carriage 19.

  The recording head of this embodiment has a four-color head configuration as shown in the overview diagram of FIG. 6, and the color order and discharge volume are Bk (20 in FIG. 6): 30 pl, C (21 in FIG. 6): 5 pl, Y (22 in FIG. 6): 5 pl, M (23 in FIG. 6): 5 pl. The number of the four color ejection portions is 304 for Bk, and 256 colors for C, Y, and M, respectively.

  Note that the recording head of the present invention may be an ejection method in which bubbles are communicated with the atmosphere that can eject a small amount of ink droplets of 10 picoliters or less at a high cycle by a single driving operation.

  Next, a first embodiment of the water-repellent state on the discharge port surface, which is a feature of the present invention, is described. FIG. 7 is a schematic view of the recording element substrate H1101 in this embodiment as viewed from the ejection port surface.

  As shown in FIG. 7, the recording element substrate H1101 has three nozzle groups in which a plurality of ejection port groups H1108 are arranged at a constant arrangement density of 600 DPI on the ejection port surface (color ejection port forming surface) A. is there. A water repellent region B subjected to a water repellent treatment is formed in the vicinity of the periphery of each discharge port group.

  In addition, the first hydrophilic region C1 is separated from the discharge port array H1108 by a separation distance H and adjacent to the water-repellent region B, and along the discharge port array, the first hydrophilic region C1 is parallel to and separated from the discharge port array H1108. Is formed. The first hydrophilic region C1 formed between the ejection port arrays H1108 is formed with a width W.

  Further, a second hydrophilic region C2 is formed in a direction adjacent to the water repellent region B and perpendicular to the ejection port array H1108. The first hydrophilic region C1 and the second hydrophilic region C2 are connected to each other. Thus, the water repellent region B is surrounded by the first hydrophilic region C1 and the second hydrophilic region C2.

  In the present embodiment, the first hydrophilic region C1 is formed with a separation distance H from the discharge port of about 35 to 250 μm and a width W of 100 to 800 μm.

  In the present embodiment, when secondary color printing is performed on a print medium, as shown in FIG. 8, a large amount of ink gathers in the first hydrophilic area C1 and moves and merges. However, since the second hydrophilic region C2 is connected to the first hydrophilic region C1, even if the ink mist combined and grown in the first hydrophilic region C1 overflows from the first hydrophilic region C1, The ink mist flows toward the second hydrophilic region C2 and is captured by the second hydrophilic region C2 away from the ejection port. In this way, since the ink mist does not enter the water-repellent region B on the ejection port side, non-ejection caused by the combined and grown ink mist being partially drawn into the corresponding one or several nozzle ejection ports. Can be prevented.

  Next, the manufacturing method which makes the said structure is demonstrated.

  FIG. 9A to FIG. 9F are schematic cross-sectional views for illustrating a basic manufacturing process of the ink jet recording head according to the present invention.

  A desired number of ink discharge energy generating elements 51 such as heating resistors (electrothermal conversion elements) are arranged on a substrate 52 shown in FIG. Next, a soluble resin layer 53 is formed on the substrate 52 including the ink discharge energy generating element 51. The dissolvable resin layer may be formed in a pattern by, for example, exposure / development with, for example, ultraviolet rays or Deep-UV light after application by dry film lamination, resist spin coating, or the like.

  As a specific example, polymethylisopropenyl ketone (ODUR-1010 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied by spin coating, dried, and then exposed and developed with Deep-UV light using a mask pattern. Thus, a pattern is formed (FIG. 9B).

  Next, as shown in FIG. 9C, a photosensitive coating resin layer 54 is formed on the soluble resin layer 53 and the substrate 52 by spin coating or the like. Further, an ink discharge base opening 56 is formed in the photosensitive coating resin layer 54 (see FIG. 9D).

  Next, the water-repellent and photosensitive surface treatment agent 55 was coated by a method such as spray coating on the photosensitive coating resin layer 54, or coating and drying a dry film on the PET, and transferring it by lamination. Next, pattern exposure was performed through the mask 58.

  As shown in FIG. 9D, the end portions of the ink discharge port base opening 56 of the photosensitive surface treatment agent 55 and the photosensitive coating resin layer 54 are exposed. Next, development is performed as shown in FIG. 9E to form an ink discharge port H1107, a water repellent region B, a first hydrophilic region C1, and a second hydrophilic region C2.

  The pattern can be formed, for example, by exposure to ultraviolet rays, Deep-UV light, or the like. More specifically, a negative resist is applied by spin coating, dried, and then subjected to pattern exposure and development with ultraviolet rays.

  Next, an ink supply port 57 is formed on the substrate 52. The ink supply port 57 is formed by chemically etching the substrate 52. For example, a Si substrate is used as the substrate 52 and is formed by anisotropic etching with a strong alkaline solution such as KOH, NaOH, TMAH. As a more specific example, a thermal oxide film formed on a Si substrate having a crystal orientation of <110> is patterned, and this Si substrate is etched with a TMAH 22% solution heated to 80 ° C. for ten hours or more. The ink supply port 57 is formed. The method of forming the ink supply port 57 is not limited to anisotropic etching. For example, before the dissolvable resin layer 53 is applied to the substrate 52, a blast mask is set on the substrate 52 and is formed by sandblasting. Is also possible.

  Subsequently, as shown in FIG. 9 (f), the soluble resin layer 53 is eluted from the ink discharge port H1107, thereby forming the ink flow path and the foaming chamber. As a method for removing the dissolvable resin layer 53, it is sufficient to perform development and drying after performing the entire surface exposure with Deep-UV light, and if necessary, it is sufficient to ultrasonically immerse in the development. Although the manufacturing method for making the said structure was described this time, it does not specifically limit about a manufacturing method and material.

  The ink mist captured in the first hydrophilic region C1 and the second hydrophilic region C2 patterned as described above adheres well to the bottom surface portion of the photosensitive coating resin 54 and a part of the end wall. By doing so, it becomes difficult to move on the discharge port surface. The thickness of the water repellent film formed on the discharge port surface is about 0.5 to 1.5 μm. The ink mist captured in the first hydrophilic region C1 and the second hydrophilic region C2 can be easily removed by cleaning the discharge port surface described later.

  Next, a state in which the discharge port surface A is cleaned by the edge 8 of the cleaning blade 7 will be described with reference to FIG.

  The cleaning blade 7 includes ink droplets and ink existing in the hydrophilic region C (the first hydrophilic region C1 and the second hydrophilic region C2) formed on the discharge port surface A and the water-repellent region B around the discharge port H1107. The mist is removed from the discharge port surface A by relatively slidingly moving the discharge port surface A in the direction of the arrow.

  In other words, the cleaning blade 7 slidably moves on the ejection port surface A in the direction of the arrow shown in FIG. 11 as the inkjet head is scanned, but at this time, the ink droplets held in the hydrophilic region 5 Is scraped off by edge 8. The removed ink droplet moves as a larger ink droplet 9 while uniting the ink mist present in the water repellent region 5.

As described above, the inks are successively combined by the cleaning blade 7 and moved on the discharge port surface A, whereby ink droplets existing on the discharge port surface A can be wiped off favorably. Since the ink to be wiped moves on the discharge port surface A as a very large lump, even if the lump of ink passes through the portion of the discharge port H1107 together with the blade, the surface tension of the ink is extremely large. Thus, ink does not enter the discharge port.
(Example 2)
FIG. 11 is a schematic plan view of the recording element substrate in this embodiment as viewed from the ejection port surface.

  In the recording head described in the first embodiment, the second hydrophilic area C2 is formed so as to surround the water-repellent area B. On the other hand, the second hydrophilic area C2 in the recording head of the present embodiment has the water-repellent area. It is formed only in the portion connected to the first hydrophilic region C1 formed between B, and the area of the portion is also narrower than that shown in the first embodiment. Thereby, the recording head can be reduced in size. On the other hand, since the ink mist tends to gather in the middle part of the ejection port array of the first hydrophilic region C1, the third region having a tapered shape is formed in the region connecting the first hydrophilic region C1 and the second hydrophilic region C2. A hydrophilic region C3 is formed. Thereby, although it is reduced in size as a whole, a sufficient hydrophilic region can be secured. In the case of the present embodiment, the hydrophilic regions C1, C2, and C3 are subjected to a hydrophilic treatment in order to further enhance the hydrophilic effect of the discharge port forming surface.

  Next, each step for producing the recording head of this embodiment will be described with reference to FIG.

  First, a blast mask was placed on a silicon substrate 52 on which an electrothermal conversion element 51 as a liquid discharge energy generating element was formed, and a through-hole 57 for supplying ink was formed by sand blasting (FIG. 12A).

  Next, polymethylisopropenyl ketone (ODUR-1010 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied as a soluble resin layer 53 on the substrate 52, dried and transferred to a laminate by lamination. did.

  Next, prebaking was performed at 120 ° C. for 20 minutes, and pattern exposure of the ink flow path was performed using the mask aligner PLA520 (Canon Inc.) as the mask 58 (FIG. 12B). The exposure was performed for 1.5 minutes, and the development was performed by spray development with 1% sodium hydroxide. The ink flow path pattern formed of the soluble resin 53 is for securing an ink flow path between the ink supply port 57 and the electrothermal conversion element 51 (FIG. 12C).

  The resist film thickness after development was 14 μm. After performing the predetermined processing for forming the ink flow path in this way, the photosensitive resin composition is then methylisobutylketone / diglyme to form a coating resin layer that is a member on which the discharge ports are arranged. It melt | dissolved in the mixed solvent and formed the photosensitive coating resin layer 54 as shown in FIG.12 (d) by spin coating. At this time, the film thickness of the photosensitive coating resin layer 54 on the soluble resin layer was 11 μm. In addition, the photosensitive resin composition for coating resin layer formation used here is as follows.

Epoxy resin EHPE-3150 (trade name: manufactured by Daicel Chemical Industries)
Diol 1,4-HFAB (trade name: manufactured by Central Glass Co., Ltd.)
Silane coupling agent A-187 (trade name: manufactured by Nihon Unicar)
Photopolymerization initiator Adekaoptomer SP-170 (trade name: manufactured by Asahi Denka Kogyo Co., Ltd.)
Next, as shown in FIG. 12E, using PLA 520, pattern exposure for forming the ink discharge port is performed through the mask 58 to make the exposed portion insoluble, and the unexposed portion can be dissolved. Left. The exposure was performed for 100 seconds, and post-baking was performed at 60 ° C. for 30 minutes.

  Next, the photosensitive coating resin layer 54 was developed with methyl isobutyl ketone to form ink discharge ports 57. In this example, a discharge port pattern having a diameter of 26 μm was formed (FIG. 12F).

  In this state, since the ink flow path pattern (resin layer) 53 still remains, it is exposed again using PLA 520 for 2 minutes and immersed in methyl lactate while applying an ultrasonic wave. FIG. The remaining ink flow path pattern (resin layer) 53 was melted as shown in FIG.

  Next, the head was heated at 150 ° C. for 1 hour to completely cure the photosensitive coating material layer 54.

  Next, a water repellent was applied using a micro spray. Nitrogen gas was gently ejected from the discharge port so that the water repellent did not enter the discharge port. CTX-CZ5A (Asahi Glass Co., Ltd.) was used as the water repellent. Next, it heated at 150 degreeC for 5 hours (FIG.12 (h)). It was 0.2 micrometer when the film thickness was measured with the dummy sample processed similarly on the glass plate.

  Next, a 3% boric acid aqueous solution as a hydrophilization promoting substance was dropped onto the water-repellent layer on the discharge port forming surface. A piece of polyimide film having a thickness of 20 μm was placed as a spacer on a portion that did not require treatment, and a quartz glass having a thickness of 1 mm was overlaid thereon. The boric acid aqueous solution was filled from the gap between the quartz glass and the discharge port forming surface in order to form a film. The side of the quartz glass in contact with the hydrophilization promoting substance was subjected to light shielding treatment except for the portion corresponding to the hydrophilic portion.

Next, a dielectric barrier discharge excimer lamp ER200-172 (manufactured by Ushio Inc.) having an emission center wavelength of 172 nm was placed immediately above the quartz glass and irradiated for 5 minutes to form a hydrophilic portion. The illuminance of the irradiated part was approximately 7 mW / cm ² .

  The discharge port forming surface of the present embodiment can be continuously formed without causing a step at the boundary between the water repellent portion (B region) and the hydrophilic portion (first to third hydrophilic regions C1 to C3). For this reason, the cleaning pressure for pressing the blade against the discharge port surface during cleaning of the discharge port surface by the blade can be reduced.

In this embodiment, when a secondary color print is performed on a print medium, a large amount of ink gathers and moves / combines in the first hydrophilic region C1. However, since the second hydrophilic region C2 is connected to the first hydrophilic region C1 via the third hydrophilic region C3, even if the ink mist is likely to overflow the first hydrophilic region C1, the second hydrophilic region C2 is connected to the first hydrophilic region C1. It is possible to flow into the hydrophilic region C2 and capture the ink mist in the second hydrophilic region C2. Therefore, the ink mist that has been combined and grown does not enter the water-repellent region B on the discharge port side, and the combined or grown ink mist is partially drawn into the corresponding one or several nozzle discharge ports, so that no non-discharge occurs.
(Example 3)
FIG. 13 is a schematic plan view of the recording element substrate in this embodiment as viewed from the ejection port surface.

  In this embodiment, a plurality of small circular water-repellent patterns B1 are interspersed in the first hydrophilic region C1 formed between the water-repellent regions B. That is, the first hydrophilic region C1 is a region formed by interspersed with minute hydrophilic regions and minute water-repellent regions.

  In the case of the present embodiment, it is possible to prevent the ink mist gathering in the first hydrophilic region C1 from being assembled due to the ink removal effect by the minute water repellent portion and the ink separation effect by the minute hydrophilic portion. Further, it can be divided by hydrophilic portions interspersed with large ink droplets. In addition, since the ink droplets captured in the scattered hydrophilic portions move to the second hydrophilic region C2, the movement of the ink droplets directly over the water-repellent region B toward the ejection port H1108 can be suppressed. As a result, it is possible to prevent the ink mist from being combined and increased to block the discharge port H1108 and cause non-discharge.

The shape of the water repellent pattern B1 is not limited to a circular shape, and the same effect can be obtained even if a square, a rectangle, a triangle, or the like is formed on the slit.
Example 4
FIG. 14 is a schematic plan view of the recording element substrate in this embodiment as viewed from the ejection port surface.

  In the hydrophilic region pattern shown in FIG. 14, the pattern width W1 of the second hydrophilic region C2 on the blade wiping start side and the pattern width W2 of the second hydrophilic region C2 on the blade wiping end side are W1 <W2. Are in a relationship. When the pattern width W1 is set to 100 to 400 μm and the pattern width W2 is set to about 400 to 800 μm, good results such as wiping of the blade and supplementing of the liquid pool caused by the ink mist binding after the secondary color printing are obtained. It was.

  FIG. 15 shows an example in which a plurality of small circular water-repellent patterns B1 are interspersed in the region on the blade wiping start side of the first hydrophilic region C1. As shown in FIG. 15, the area S1 of the hydrophilic portion excluding the scattered water repellent pattern B1 in the first hydrophilic region C1 on the blade wiping start side, and the area S2 of the end portion hydrophilic region on the blade wiping end side The same effect can be obtained by setting S1 <S2. The above example is an example of horizontal wiping in which the wiper direction is parallel to the nozzle row arrangement direction.

  FIG. 16 shows an example of vertical wiping in which the wiping direction by the blade is perpendicular to the nozzle row arrangement direction. Also in this case, the relationship between the area S1 of the hydrophilic portion excluding the scattered water repellent pattern B1 in the first hydrophilic region C1 on the blade wiping start side and the area S2 of the end hydrophilic region on the blade wiping end side, The same effect can be obtained by setting S1 <S2.

  The above-described embodiments may be combined in any way.

1 is an exploded perspective view of an ink jet recording head of the present invention. FIG. 2 is a partially cutaway perspective view of an inkjet recording head that discharges black ink. FIG. 3 is a partially cutaway perspective view of an ink jet recording head that discharges color ink. It is an external view of the mechanism part of an inkjet printer. It is an external view of a head cartridge used in an ink jet printer. It is the external view which looked at the head cartridge used for an inkjet printer from the electrode side. FIG. 2 is a schematic view of the recording element substrate according to the first exemplary embodiment of the present invention as viewed from the discharge port surface. It is the figure which showed typically a mode that the ink moved and united in a hydrophilic region. FIG. 5 is a schematic cross-sectional view showing a basic manufacturing process of the ink jet recording head according to Example 1 of the invention. It is a figure explaining the cleaning condition of the discharge port surface by a blade. FIG. 6 is a schematic view of a recording element substrate according to a second embodiment of the present invention as viewed from a discharge port surface. It is typical sectional drawing which shows the basic manufacturing process of the inkjet recording head by Example 2 of this invention. FIG. 6 is a schematic view of a recording element substrate in Example 3 of the present invention as viewed from the discharge port surface. FIG. 6 is a schematic view of an example of a recording element substrate in Example 4 of the present invention as viewed from the discharge port surface. FIG. 10 is a schematic view of another example of the recording element substrate in Example 4 of the present invention as viewed from the discharge port surface. FIG. 10 is a diagram schematically illustrating still another example of the recording element substrate in Example 4 of the present invention as viewed from the discharge port surface. It is a schematic diagram which shows the discharge port formation surface of the conventional inkjet recording head. It is a figure explaining the behavior of the discharged ink droplet. It is a figure which shows the time-dependent change of the discharge state of the ink droplet of the discharge method with which air bubbles communicate with air | atmosphere. It is a figure which shows the size and adhesion amount of the ink drop adhering to the discharge port formation surface. It is a figure which shows an example of the conventional inkjet recording head which has a water-repellent surface in the discharge port formation surface.

Explanation of symbols

A discharge port forming surface B water repellent region C1 first hydrophilic region C2 second hydrophilic region H1108 discharge port array

Claims (10)

In an inkjet head in which a discharge port forming surface is arranged with a plurality of discharge port arrays configured of a plurality of discharge ports for discharging ink,
The discharge port formation surface has a water repellent region surrounding the region having the discharge port row for each discharge port row, and is disposed adjacent to the water repellent region and extends in the direction of the discharge port row. A plurality of first hydrophilic regions provided individually, and a second hydrophilic region adjacent to the water-repellent region and extending in a direction orthogonal to the discharge port array, An ink jet recording head characterized in that the hydrophilic region of the ink is connected to the second hydrophilic region. The inkjet recording head according to claim 1, wherein the first hydrophilic regions between the ejection port arrays are arranged in a band shape. The ink jet recording head according to claim 2, wherein each of the first hydrophilic regions arranged in the band shape has a region having an equal width. 4. The ink jet recording head according to claim 1, wherein the first hydrophilic region has a region extending in a tapered shape toward an end portion direction of the ejection port array. 5. 5. The ink jet recording head according to claim 1, wherein the first hydrophilic area is provided with a plurality of minute water-repellent areas interspersed. 6. The discharge port forming surface is wiped by a cleaning blade in a direction in which the first hydrophilic region extends, and the area of the second hydrophilic region on the wiping start side by the cleaning blade is the second wiping end side. The inkjet recording head according to claim 1, wherein the inkjet recording head is smaller than an area of the hydrophilic region. The discharge port forming surface is wiped in the arrangement direction of the plurality of first hydrophilic regions formed in parallel by a cleaning blade, and the area of the first hydrophilic region on the wiping start side by the cleaning blade is the end of wiping The inkjet recording head according to claim 1, wherein the inkjet recording head is smaller than an area of the first hydrophilic region on the side. The inkjet recording head according to claim 6 or 7, wherein the width of the hydrophilic region on the wiping start side by the cleaning blade is narrower than the width of the hydrophilic region on the wiping end side. 9. The ink jet recording head according to claim 6, wherein a plurality of minute water-repellent regions are provided in the hydrophilic region on the wiping start side by the cleaning blade. The inkjet recording head according to claim 1, and cleaning means for cleaning the discharge port forming surface by operating relative to the discharge port forming surface. An ink jet recording apparatus.

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