JP2005144919A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head that can print high quality images at high speeds by solving the problem of causing white streaks in a printed image in parts corresponding to joints between recording element boards due to the deviation of discharged liquid drops from an end discharge opening due to airflow caused by discharge when adjacent recording element boards are arranged at a specified interval in a recording head in which a plurality of the recording element boards are arranged in a zigzag from in the direction of discharge opening rows. <P>SOLUTION: In the inkjet recording head in which a plurality of recording element boards having discharge openings arranged at a specified interval are arranged in a zigzag form in a discharge opening row direction, the end discharge opening of a certain recording element board and the adjacent side end discharge opening of a recording element board adjacent to the end discharge opening side are not arranged at the specified interval in the discharge opening row direction, and the adjacent recording element boards are arranged in the direction of approaching each other by a distance a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording head used in an ink jet recording apparatus that performs a recording operation by discharging a liquid such as ink. The present invention can be applied to a general printing apparatus, a copying machine, a facsimile having a communication system, an apparatus such as a word processor having a printing unit, or a multifunction recording apparatus combining these apparatuses.

  Inkjet recording devices are low in running cost, can be miniaturized, and can easily handle color image recording using multiple colors of ink. Used and commercialized.

  On the other hand, as an energy generating element that generates energy for ejecting ink from the ejection port of the recording head, an element that uses an electromechanical transducer such as a piezo element, or an electromagnetic wave such as a laser emits heat to generate heat. There are those that discharge ink droplets by the action of, and those that heat a liquid by an electrothermal conversion element having a heating resistor.

  Among them, an ink jet recording system head that ejects ink droplets using thermal energy can perform high-resolution recording because the ejection ports can be arranged at high density. Among them, a recording head using an electrothermal transducer as an energy generating element can be easily reduced in size, and can sufficiently overcome the advantages of IC technology and micromachining technology that have made remarkable progress in technology and improved reliability in the recent semiconductor field. It is advantageous because it can be used in half, easy to mount with high density and inexpensive to manufacture.

  Recently, in order to perform higher-detail printing, a method of creating a nozzle for ejecting ink with high accuracy using a photolithographic technique has been used.

  In recent years, in order to realize high-detail image recording at higher speed, it is also desired to realize a recording head having a longer print width. Specifically, a head having a length of 4 inches to 12 inches has been required.

  As a general ink jet recording apparatus, a method of performing printing by scanning an ink jet recording head on a recording material such as paper while discharging ink is widely known. An inkjet recording apparatus that can perform printing at high speed by fixing a long head on a conveying belt that conveys a recording material and scanning the recording material is also known.

  When an ink jet recording head having such a long print width is constituted by a single recording element substrate, the recording element substrate becomes very long, and the recording element substrate may be cracked or warped, or the recording element substrate itself Problems such as a decrease in the yield of. Therefore, in Patent Document 1 and the like, a configuration has been devised in which a plurality of recording element substrates having an appropriate length (having an appropriate number of nozzles) are arranged in a staggered manner to achieve a recording head having a long print width as a whole. ing.

  FIG. 11 is a diagram illustrating the ink jet recording head having such a configuration. FIG. 11 is a conceptual diagram showing a part of a connecting portion of a plurality of staggered recording element substrates, in which constituent members other than the recording element substrate are omitted for easy understanding, and a discharge port of the recording element substrate is shown. It is the figure seen from the surface. The other connecting portions have the same configuration as that shown in the figure.

A recording element substrate H1100c is disposed adjacent to a certain recording element substrate H1100b and along the discharge port array direction. The discharge ports H1105b and H1105c are arranged in a staggered manner in the recording element substrate at a specified pitch P. Then, the end discharge port H1105b-1 of the recording element substrate H1100b and the end discharge port H1105c-1 of the recording element substrate H1100c are spaced by the same distance as the specified pitch P in the discharge port array direction. A recording element substrate is disposed. For this reason, the arrangement of the ejection ports in the direction of the ejection port array is configured to be continuously arranged at a specified pitch P beyond the adjacent recording element substrate. In the direction perpendicular to the ejection port array direction, the adjacent recording element substrates (or ejection ports of the adjacent recording element substrates) are arranged apart from each other. This is inevitably separated due to the configuration of the recording head. In general, in the direction orthogonal to the ejection port array direction, the ejection ports of the adjacent recording element substrates are spaced apart by several mm or more.
Japanese Patent Laid-Open No. 5-24192

  However, the recording head configured as shown in FIG. 11 has the following problems.

  FIG. 12 is a conceptual diagram schematically showing how ink droplets are ejected from the recording head of FIG. FIG. 12 shows the ink droplet ejection state when ink droplets are continuously ejected from all ejection ports and so-called solid printing is performed on the recording medium K1000. The recording element substrates H1100a to c are continuously arranged as described above, and the discharge ports (not shown) are arranged in the left-right direction in the drawing.

  When the image data is solid, all the ejection energy generation units (not shown) corresponding to the ejection ports are driven at a high driving frequency. For this reason, along with the movement of the ink droplet K1001 ejected from the ejection port toward the recording medium K1000, the viscous air existing around the ink droplet K1001 moves while being dragged by the motion of the ink droplet K1001. As a result, from the vicinity of the discharge port surface H1105M where the discharge port of the recording element substrate H1100 opens to the vicinity of the recording medium K1000, the pressure tends to be lower than the surroundings of the recording head, and the surrounding air flows as an air flow to the reduced pressure region. In particular, the ink droplets K1001 ejected from the ejection ports located at both ends in the arrangement direction of the ejection ports are attracted to the center side in the arrangement direction, and may not be ejected to the intended position with respect to the recording medium K1000. found. For this reason, a plurality of ejected droplets at both ends of each of the recording element substrates H1100a to H1100c are attracted to the central portion. Since the adjacent recording element substrates are arranged away from each other in the depth direction of FIG. 12, the ink droplet K1001 from the end discharge port is attracted to the central portion even at the connecting portion between the recording element substrates. It has been.

  FIG. 13 schematically shows a part of a solid print image formed on a recording medium when printing is performed under such a phenomenon. FIG. 13 is an image printed at an ejection port in the vicinity of a joint between adjacent recording element substrates. A part of the image area printed on the recording element substrate H1100a is 2A, and a part of the image area printed on the recording element substrate H1100b is 2B. Each image area is formed by collecting a plurality of ink dots 1A and 1B.

  It will be understood that white stripes 3 are formed between the image area 2A and the image area 2B.

  Such an inconvenience is caused in an ink jet printer that discharges a small amount of ink droplets of 10 picoliters or less at a high frequency by a single driving operation by setting the arrangement interval (specified pitch P) of the ejection openings of each recording element substrate to be narrow. It turned out to be particularly prominent. When the arrangement interval of the ejection ports is 1200 dpi (21 μm), the ejection amount ejected from one ejection port at a time and the amount of deviation of the ejected ink droplets at the end ejection port (= half the amount of white stripe 3) An example of a graph representing the relationship is shown in FIG.

  The reason why the phenomenon appears remarkably when the size of the ink droplet is reduced is that the ratio of the ink droplet surface area increases due to the relationship of the ink droplet surface area (projected area) to the ink droplet weight, while the movement of the droplet due to the air flow. This is because the larger the ratio, the more affected.

  In order to prevent such a problem, by increasing the size of the ink droplets ejected from the ejection ports located at both ends in the arrangement direction of the ejection ports, that is, by increasing the inertial mass of the ink droplets, It is also possible to suppress deviations in the ejection trajectory of the ink droplets ejected from the located ejection ports. However, enlarging the ink droplets is an obstacle to forming a high definition and high gradation image. Further, the penetration of ink droplets into the recording medium is delayed, and there is a high possibility that the print image will be deteriorated as the print medium swells. Alternatively, it is possible to alleviate the above-described problems by suppressing the driving frequency for the discharge energy generating unit to be low. However, when the drive frequency for the discharge energy generating unit is set low, the printing speed becomes slow, and it becomes impossible to meet the user's need to print out at high speed.

  Therefore, in view of the above-described problems of the prior art, the present invention provides a recording head in which a plurality of recording element substrates are arranged in a staggered manner in the discharge port array direction, and the adjacent recording element substrates are arranged at a specified pitch. This solves the problem that the discharge droplets from the end discharge ports are biased by the air flow caused by the discharge, and white streaks occur in the printed image of the portion corresponding to the connecting portion between the recording element substrates. An object of the present invention is to provide an ink jet recording head capable of printing at a high speed.

  In order to achieve the above object, the inkjet recording head of the present invention has a plurality of ejection openings for ejecting a recording liquid, and the ejection opening is arranged at intervals of a specified pitch. A plurality of staggered arranged end discharge ports of a certain recording element substrate, and end discharge ports on the adjacent side of the recording element substrate adjacent to the end discharge port side are arranged in the discharge port arrangement direction. The recording element substrates are not arranged at regular pitch intervals, but adjacent recording element substrates are arranged in a direction approaching each other by a distance a.

  Further, the distance a is a discharge port arrangement direction when droplets discharged from the end discharge ports are landed on the recording medium, which is caused by an air flow generated along with discharge of the recording liquid from the discharge port group. The distance a is a sum of the deviation amounts of the droplets from the end discharge ports of the adjacent recording element substrates.

  Further, the deviation amount is a deviation amount due to a stream of liquid droplets ejected from the recording element substrate at a maximum print duty of the recording head.

  As is apparent from the above description, according to the present invention, in a recording head in which a plurality of recording element substrates are arranged in a staggered manner in the discharge port array direction, when adjacent recording element substrates are arranged at a specified pitch, This can solve the problem that the discharge droplets from the end discharge ports are biased by the air flow caused by the above, and white streaks are generated in the printed image of the portion corresponding to the connecting portion between the recording element substrates. As a result, an ink jet recording head capable of printing a high-quality image at high speed can be provided.

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

(First embodiment)
FIG. 1 to FIG. 6 are explanatory diagrams for explaining each of the preferred recording head, driving circuit, and ink jet recording apparatus to which the present invention is applied or applied, and their respective relationships. Hereinafter, the entire configuration will be described with reference to these drawings while describing the configuration of each part.

(1) Description of Recording Head As shown in FIG. 1, the recording head H1000 is an electrothermal transducer that generates thermal energy for generating thermal energy for causing film boiling to the ink in accordance with an electrical signal. The recording head is a bubble shooter (registered trademark) side shooter type that performs recording using the.

  The recording head H1000 includes a recording element unit H1001 and an ink supply unit H1002, as shown in the exploded perspective view of FIG. Further, as shown in the exploded perspective view of FIG. 3, the recording element unit H1001 includes a recording element substrate H1100, a first plate H1200, an electric wiring substrate H1300, a second plate H1400, and a filter member H1600. The ink supply unit H1002 includes an ink supply member H1500, a joint rubber H1700, a tube H1802, and an ink tank H1800 as shown in the exploded perspective view of FIG.

(1-1) Recording Element Unit FIG. 5A is a diagram illustrating the configuration of the recording element substrate H1100, and FIG. 5B is a cross-sectional view taken along line AA shown in FIG. The recording element substrate H1100 has a thin film formed of, for example, a Si substrate H1108 having a thickness of 0.5 to 1 mm. Further, an ink supply port H1101 consisting of a long groove-like through-hole is formed as an ink flow path, and electrothermal conversion elements H1102 are arranged in a staggered pattern on each side of the ink supply port H1101, respectively. The electric wiring such as the element H1102 and Al is formed by a film forming technique. An electrode H1103 is provided to supply power to the electrical wiring. The ink supply port H1101 performs anisotropic etching using the crystal orientation of the Si substrate H1108. When the wafer surface has a crystal orientation of <100> and a thickness direction of <111>, the etching proceeds at an angle of about 54.7 degrees by anisotropic etching (KOH, TMAH, humanradine, etc.) . Using this method, etching is performed to a desired depth. A nozzle plate H1110 is provided on the Si substrate H1108, and an ink flow path H1104, a nozzle H1105, and a foaming chamber H1107 corresponding to the electrothermal conversion element H1102 are formed by a photolithography technique. The nozzle H1105 is provided so as to face the electrothermal conversion element H1102, and causes the ink supplied from the ink supply port H1101 to generate bubbles by the electrothermal conversion element H1102 to discharge the ink. .

  The first plate H1200 is made of, for example, an alumina (Al2O3) material having a thickness of 1.5 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. The material of the first plate H1200 is, for example, any of silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si3N4), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). May be. An ink supply port H1201 for supplying ink to the recording element substrate H1100 is formed in the first plate H1200, and the ink supply port H1101 of the recording element substrate H1100 is connected to the ink supply port H1201 of the first plate H1200. Correspondingly, the recording element substrate H1100 is bonded and fixed to the first plate H1200 with high positional accuracy. The first adhesive H1202 is desirably, for example, a material having a low viscosity, a thin adhesive layer formed on the contact surface, a relatively high hardness after curing, and ink resistance. The first adhesive H1202 is, for example, a thermosetting adhesive mainly composed of an epoxy resin or an ultraviolet curing combined thermosetting adhesive, and the thickness of the adhesive layer is desirably 50 μm or less. The first plate H1200 has an X-direction reference H1204, a Y-direction reference H1205, and a Z-direction reference H1206, which are positioning references.

  The recording element substrates H1100 are arranged in a staggered manner on the first plate H1200 as shown in FIG. 1, and wide recording with the same color is possible. For example, four recording element substrates H1100a, H1100b, H1100c, and H1100d each having a nozzle group length of 1 inch + α are arranged in a staggered manner to enable recording of a width of 4 inches.

  In addition, the end of the ejection port group of each recording element substrate is arranged so as not to have a substantial gap from the end of the ejection port group of the adjacent recording element substrate, thereby preventing a gap from being generated in printing by each recording element substrate. doing.

  The external wiring substrate H1300 applies an electrical signal for ejecting ink to the recording element substrate H1100, and corresponds to an opening for incorporating the recording element substrate H1100 and an electrode H1103 of the recording element substrate H1100. It has an electrode terminal H1302 and an external signal input terminal H1301 for receiving an electrical signal from the recording apparatus main body located at the end of the wiring. The external wiring board H1300 and the recording element board H1100 are electrically connected. For example, the electrode H1103 of the recording element board H1100 and the electrode terminal H1302 of the external wiring board H1300 are connected to a gold wire H1303 (not shown). It is electrically connected by the wire bonding technique used. As a material of the external wiring board H1300, for example, a flexible wiring board having a two-layer wiring structure is used.

  The second plate H1400 is, for example, a plate member having a thickness of 0.2 to 1 mm. The second plate H1400 has a shape having an opening larger than the outer dimension of the recording element substrate H1100 bonded and fixed to the first plate H1200. The second plate H1400 is bonded to the first plate H1200 with a second adhesive H1203 so that the recording element substrate H1100 and the external wiring substrate H1300 can be electrically connected in a plane, and further, the external wiring substrate. The back surface of H1300 and the third adhesive H1306 are bonded and fixed.

  A groove formed by the opening H1402 of the second plate and the side surface of the recording element substrate H1100 is filled with the first sealant H1304, and the electrical mounting portion of the electrical wiring substrate H1300 is sealed. Further, the electrode H1103 of the recording element substrate is sealed with a second sealant H1305 to protect the electrical connection portion from corrosion by ink and external impact.

  Further, a filter member H1600 for removing foreign matters mixed in the ink is bonded and fixed to the back surface side ink supply port H1201 of the first plate H1100.

(1-2) Ink Supply Unit The ink supply member H1500 is formed by resin molding, for example, and includes a common liquid chamber H1501 and a Z-direction reference surface H1502. The Z reference plane H1502 positions and fixes the recording element unit and serves as the Z reference for the recording head H1000.

  In addition, a joint rubber H1700 is provided in the ink supply port H1504 that supplies ink from the ink tank H1800 to prevent ink from evaporating from the joint portion.

  The ink supply tube H1802 extending from the ink tank H1800 and the ink supply unit H1500 are connected by a needle H1801 provided at the tip of the tube passing through the joint rubber H1700. Ink used at the time of ejection is supplied from the ink tank H1800 through the ink supply tube H1802 to the common liquid chamber H1501 of the ink supply unit H1500, and is supplied to the recording element unit H1001 through the filter member H1600.

(1-3) Coupling of Recording Element Unit and Ink Supply Unit As shown in FIG. 2 described above, the recording head H1000 is completed by coupling the recording element unit H1001 to the ink supply member H1500.

  The coupling is performed as follows.

  The opening of the ink supply member H1500 and the recording element unit H1001 are sealed with a third sealant H1503, and the common liquid chamber H1501 is sealed. Then, the Z reference H1502 of the recording element unit H1001 is positioned and fixed to the Z reference H1502 of the ink supply member by, for example, a screw H1900. The third sealant H1503 is desirably a sealant that has ink resistance, is cured at room temperature, and can withstand the linear expansion difference between different materials.

  Further, the external signal input terminal H1301 portion of the recording element unit H1001 is positioned and fixed on the back surface of the ink supply member H1501, for example.

(2) Description of Inkjet Recording Device As shown in FIG. 6, the inkjet recording device M4000 of the present invention includes, for example, recording heads for six colors corresponding to photographic image quality recording. The recording head H1000Bk is a recording head for black ink, the recording head H1000C is for cyan ink, the recording head H1000M is for magenta ink, the recording head H1000Y is for yellow ink, the recording head H1000LC is for light cyan ink, and the recording head H1000LM is light. For magenta ink. These recording heads H1000 are fixedly supported by positioning means and electric contacts M4002 of a carriage M4001 mounted on the recording apparatus main body M4000.

  These recording heads are controlled by a drive circuit to perform recording on a recording medium.

  Next, the characteristic configuration and operation of the above embodiment will be described more specifically based on the following embodiments.

  FIG. 7 is a conceptual diagram showing a part of a connecting portion of a plurality of staggered recording element substrates, in which constituent members other than the recording element substrate are omitted for easy understanding, and the ejection openings of the recording element substrate It is the figure seen from the surface. Also, the connecting portions of the other recording element substrates have the same configuration as in this figure.

  A recording element substrate H1100c is disposed adjacent to a certain recording element substrate H1100b and along the discharge port array direction. The discharge ports H1105b and H1105c are arranged in a staggered manner in the recording element substrate at a specified pitch P.

  Then, each recording element substrate is arranged such that the end discharge port H1105b-1 of the recording element substrate H1100b and the end discharge port H1105c-1 of the recording element substrate H1100c have an interval P1 in the discharge port array direction. Has been placed.

  In the direction perpendicular to the ejection port array direction, the adjacent recording element substrates (or ejection ports of the adjacent recording element substrates) are arranged apart from each other. This is inevitably separated due to the configuration of the recording head. In general, in the direction orthogonal to the ejection port array direction, the ejection ports of the adjacent recording element substrates are spaced apart by several mm or more.

  In this embodiment, the discharge port arrangement of each recording element substrate is such that the discharge ports arranged in a straight line are arranged at an interval of 600 dpi = 42.3 μm. Further, the discharge port groups arranged in a straight line are arranged in two rows, and these two rows are shifted by a distance of 1200 dpi = 21.1 μm, which is a half distance of 600 dpi. Therefore, by combining these two rows, one recording element substrate has a discharge port group of 1200 dpi. Therefore, the specified pitch P is 1200 dpi = 21.1 μm. In addition, the interval in the direction orthogonal to the discharge port array direction of the two discharge port groups is 210 μm.

  Further, the distance P1 is not the same as the specified pitch P, unlike the conventional configuration.

  The ink droplets on the end side are biased toward the center side by the air flow generated along with the ejection of the ink droplets from the ejection port group of the recording element substrate. At this time, the end portion ejection ports (H1105b-1 and H1105c- The amount of deflection of the ink droplets ejected from 1) in the ejection port array direction when landing on the recording medium is a0 and a1, respectively, and the sum is a (= a0 + a1). At this time, the adjacent recording element substrates are arranged so that the value of P1 is P1 = P−a.

  Thus, by arranging the recording element substrates close to each other by the sum of the amount of deflection due to the airflow at the end discharge port, the white stripe 3 (FIG. 13) as described in the conventional recording head is generated. Therefore, it can be easily understood that a high-quality printed image can be obtained.

  Note that it is desirable to adopt a value at the maximum print duty of the recording head as the amount of deviation here.

  Furthermore, an example of the set value of P1 in the recording head of this embodiment will be given. As an example of the configuration of the recording head, the ejection amount ejected from one ejection port at a time is 4.5 picoliters (pl), and the ejection speed of the ink droplets is about 10 to 15 m / s. . Further, the discharge amount is obtained by setting the discharge port diameter to 18 μm. The maximum print duty is 100%, that is, a print mode in which discharge is continuously performed from all discharge ports is provided. The driving frequency at this time is 22 kHz. In addition, the recording apparatus is configured such that the interval between the discharge port surface where the discharge port of the recording element substrate opens and the recording medium is about 1.2 mm.

  In the recording head having such a configuration, the amount of deflection in the discharge port arrangement direction due to the air flow of the end nozzles when printing with the maximum print duty of 100% is about 11 μm. Therefore, the value a is 11 × 2 = 22 μm in this embodiment. Therefore, in this case, the interval P1 between the end discharge ports of the adjacent recording element substrates may be set to 21.1-22 = −0.9 μm. That is, in FIG. 7, the recording element substrate is arranged so that the end discharge port H1105c-1 has a distance of 0.9 μm on the left side with respect to the end discharge port H1105b-1. .

  By the way, the amount of deviation due to the airflow at the end discharge port varies depending on the print duty. The higher the print duty, the greater the influence of the airflow and the greater the amount of deviation. Therefore, when the duty is low, an image having high quality can be obtained even when the duty is low by correcting and controlling the amount of ink droplets to be ejected and the manner in which the ink droplets are ejected in the vicinity of the joint portion.

  In addition, since the amount of deflection due to the airflow changes not only with the ejection amount but also with the drive frequency and the arrangement interval of the ejection ports, the value of P1 may be set according to the specifications of the recording head.

  As is clear from the above description, the ink jet recording head of the present invention can print a high-quality image at a high speed without white streaking unlike the conventional configuration.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a conceptual diagram showing a part of a connecting portion of a plurality of staggered recording element substrates, as in FIG. 7, in which components other than the recording element substrate are omitted for easy understanding. It is the figure seen from the discharge outlet surface of the element substrate. Also, the connecting portions of the other recording element substrates have the same configuration as in this figure.

  A recording element substrate H1100c is disposed adjacent to a certain recording element substrate H1100b and along the discharge port array direction. Further, as in FIG. 7, the end discharge port H1105b-1 of the recording element substrate H1100b and the end discharge port H1105c-1 of the recording element substrate H1100c have a spacing P1 in the discharge port array direction. Each recording element substrate is arranged. The distance P1 may be set in the same manner as the value described in the first embodiment. Conventionally, the recording element substrates are arranged close to each other by the sum of the amount of deflection due to the airflow at the end discharge ports. A high-quality print image in which the white streak 3 does not occur as described in the recording head having the configuration can be obtained.

  Further, in FIG. 8, the recording element substrates H1100b and H1100c are arranged at the end discharge port groups H1106b-E and H1106c-E disposed at both ends thereof, and the central discharge port group H1106b-C disposed at the other central portion. And the end discharge port group and the central discharge port group have different arrangement intervals of the discharge ports. Whereas the arrangement interval of the central discharge port group is the prescribed pitch P, the arrangement interval of the end portion discharge orifice group is Pe wider than the prescribed pitch. In this embodiment, P is set to 42.8 μm, which is 0.5 μm wider than that, whereas P is 42.3 μm of 1200 dpi. Further, the end discharge port group includes up to 22 discharge ports counted from the end discharge port H1105b-1. Therefore, in the discharge port H1105b-1 at the extreme end, it is arranged so as to spread by 11 μm toward the end side compared to the case where all the discharge ports are arranged at 1200 dpi. Even the discharge ports in the end discharge port group are less spread as they approach the center.

  The reason why such a configuration is adopted in the second embodiment is that the occurrence of white streaks is suppressed in the first embodiment, but the ejected ink droplets at both ends are twisted to the central portion by the air flow. This is because, depending on the image to be printed, the ink dots may become dense on the printing medium at both ends, resulting in unevenness. Therefore, the unevenness on both ends can be suppressed by the configuration of the second embodiment.

  It should be noted that the amount of deviation due to the airflow is the largest at the endmost outlets at both ends, and the amount of deviation becomes smaller as going to the center. In the form of the present embodiment, there are about 10 to several tens of discharge ports that are affected by the airflow. In this embodiment, the number of end discharge port groups is 22 and the interval is increased by 0.5 μm. However, depending on the number of discharge ports that are affected by the air flow and affect the image, the end discharge ports are increased. What is necessary is just to set suitably the number of exit groups, and the space | interval of a discharge outlet.

  In this embodiment, the interval between the discharge ports of the end portion discharge port group is constant with Pe. However, the interval may be changed according to the direction of twisting due to the air current, such as gradually increasing the interval.

  As described above, according to the second embodiment, it is possible to configure an ink jet recording head capable of printing a high-quality image without white streaking unlike the conventional configuration and without unevenness at high speed.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a conceptual diagram showing a part of a connecting portion of a plurality of staggered recording element substrates, as in FIG. 7, in which components other than the recording element substrate are omitted for easy understanding. It is the figure seen from the discharge outlet surface of the element substrate. Also, the connecting portions of the other recording element substrates have the same configuration as in this figure.

  A recording element substrate H1100c is disposed adjacent to a certain recording element substrate H1100b and along the discharge port array direction. Similarly to the first embodiment of FIG. 7, the end discharge port H1105b-1 of the recording element substrate H1100b and the end discharge port H1105c-1 of the recording element substrate H1100c are P1 in the discharge port array direction. The respective recording element substrates are arranged so as to have an interval. The distance P1 may be set in the same manner as the value described in the first embodiment. Conventionally, the recording element substrates are arranged close to each other by the sum of the amount of deflection due to the airflow at the end discharge ports. A high-quality print image in which the white streak 3 does not occur as described in the recording head having the configuration can be obtained.

  Further, in FIG. 9, the recording element substrates H1100b and H1100c are arranged at the end discharge port groups H1106b-E and H1106c-E disposed at both ends thereof and the central discharge port group H1106b-C disposed at the other central portion. And H1106c-C, and the size of the discharge port is different between the end discharge port group and the central discharge port group. Note that the arrangement intervals of the discharge ports in both the discharge port groups are equal.

  The diameter db-C of the discharge port of the central discharge port group is 18 μm as described above, while the diameter db-E of the discharge port of the end discharge port group is 17 to 17.5 μm. By changing the size of the discharge port, the discharge amount discharged from one discharge port at a time changes. With the above discharge port size, the discharge amount of the central discharge port group is 4.5 picoliters (pl), whereas the discharge amount of the end discharge port group is 3.5 to 4 picoliters (pl) )

  As described in the description of the second embodiment, the ink dots may become dense on the printing medium at the discharge ports on both ends of the recording element substrate, resulting in unevenness. Thus, the unevenness on both ends can be suppressed by reducing the discharge amount of the end discharge port group.

  In this embodiment, as a method of reducing the discharge amount at the end, the discharge port diameter is reduced. However, the present invention is not limited to this. For example, the size of the recording element corresponding to the discharge port at the end is used. The ejection amount may be reduced by changing the discharge energy to reduce the ejection amount.

  As described above, according to the third embodiment, it is possible to configure an ink jet recording head capable of printing a high-quality image without white streaking unlike the conventional configuration and without unevenness at high speed.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a conceptual diagram showing a part of a connecting portion of a plurality of staggered recording element substrates, as in FIG. 7, in which components other than the recording element substrate are omitted for easy understanding. It is the figure seen from the discharge outlet surface of the element substrate. Also, the connecting portions of the other recording element substrates have the same configuration as in this figure.

  A recording element substrate H1100c is disposed adjacent to a certain recording element substrate H1100b and along the discharge port array direction.

  Further, in FIG. 10, the end of each ejection element group of each recording element substrate is provided with an overlapping area with the end part of the ejection opening group of the adjacent recording element substrate. The discharge port groups are H1106b-X and H1106c-X.

  Further, the recording element substrate H1100b end discharge port H1105b-1 and the corresponding recording element substrate H1100c corresponding discharge port H1005c-2 have a P1 interval in the discharge port array direction. An element substrate is arranged. Similarly, the end discharge port H1105c-1 of the recording element substrate H1100c and the corresponding discharge port H1005b-2 of the recording element substrate H1100b corresponding to this have an interval of P1 in the discharge port array direction.

  The distance of P1 may be set in the same manner as the value described in the first embodiment. In the case of this embodiment, the amount of deflection due to the airflow at the end discharge port H1105b-1 (or H1105c-1), As described in the conventional recording head, the recording element substrates are arranged close to each other by the sum of the amount of deflection due to the airflow of the corresponding outlet H1105c-2 (or H1105b-2) to the end outlet. A high-quality print image in which no white streak 3 is generated is obtained.

  The maximum print duty in FIG. 10 is 100% as in the above-described embodiment except for the overlapping discharge port group. However, the overlapping portion is set to 50% duty, which is half of that, so that it becomes 100% in total. Yes. FIG. 15 shows an example of a graph showing the relationship between the print duty of the printing apparatus and the amount of deviation of the ink droplets discharged from the end discharge ports. As can be seen from the figure, the lower the print duty, the lower the amount of deviation of the discharge port due to the airflow.

  Taking this into consideration, an example of P1 in this embodiment is obtained. The amount of deflection (maximum print duty) due to the air flow at the end discharge ports H1105b-1 and H1105c-1 is 6 μm, and the corresponding discharge port H1105c-2 And H1105b-2 is less affected by airflow because it is located at the center from the end. In this example, since the corresponding discharge port is in a place where it is hardly affected by the airflow (discharge port from the center of several tens or more from the end portion), the amount of deviation is almost zero. Therefore, the sum a of the deflection amounts is 6 μm, and P1 = 21.1−6 = 15.1 μm.

  As described in the above-described embodiment, there are cases where the ink dots become dense and uneven on the print medium at the discharge ports on both ends of the recording element substrate. By providing the ejection port group, the ink dots are randomly arranged on the recording medium, so that unevenness is not noticeable. Further, since the maximum print duty of the overlapping portion is reduced, the amount of deviation due to the air current is reduced, and the amount of approaching the adjacent recording element substrate can be reduced, so that the influence on the printed image at the time of low duty is reduced. However, if the overlapping area is excessively increased, the number of areas that can be printed with the same number of recording element substrates is reduced. Therefore, it is preferable to determine the number of overlapping ejection port groups in consideration of cost and performance.

  As described above, according to the fourth embodiment, it is possible to configure an ink jet recording head capable of printing a high-quality image without white streaking unlike the conventional configuration and without unevenness at high speed.

1 is an external perspective view of a recording head according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the recording head illustrated in FIG. 1. FIG. 3 is an exploded perspective view of the recording element unit shown in FIG. 2. FIG. 3 is an exploded perspective view of the ink supply unit shown in FIG. 2. 2A and 2B are diagrams illustrating a recording element substrate, in which FIG. 1A is an external perspective view, and FIG. It is a figure explaining an inkjet recording device. It is a figure explaining the 1st Example of this invention. It is a figure explaining the 2nd Example of this invention. It is a figure explaining the 3rd Example of the present invention. It is a figure explaining the 4th Example of this invention. It is a figure explaining a conventional structure. FIG. 6 is a conceptual diagram schematically illustrating how ink droplets are ejected from a recording head having a conventional configuration. It is a conceptual diagram which represents typically the image printed with the recording head of the conventional structure. 6 is an example of a graph showing a relationship between a discharge amount discharged at one time from one discharge port of a recording head and a deflection amount of ink droplets discharged from an end discharge port. 6 is an example of a graph showing the relationship between the print duty of the recording apparatus and the amount of deflection of the ink droplets discharged from the end discharge ports.

Explanation of symbols

H1000 recording head
H1001 Recording element unit
H1002 Ink supply unit
H1100, H1100a to d Recording element substrate
H1101 Ink supply port
H1102 electrothermal transducer
H1103 electrode
H1104 Ink channel
H1105, H1105a to d Discharge port
H1105b-1, H1105c-1 End outlet
H1105b-2, H1105c-2 Corresponding discharge port to end discharge port
H1105M Discharge port surface
H1106 Discharge port group
H1106b-E, H1106c-E End discharge port group
H1106b-C, H1106c-C Central outlet group
H1106b-X, H1106c-X Overlap outlet group
H1107 Foaming chamber
H1108 Si substrate
H1110 Nozzle plate
H1200 1st plate
H1201 Ink supply port
H1202 First adhesive
H1203 Second adhesive
H1204 X direction reference
H1205 Y direction reference
H1206 Z direction reference
H1300 External wiring board
H1301 External input terminal
H1302 Electrode terminal
H1304 First sealant
H1305 Second sealant
H1306 Third adhesive
H1307 Bump
H1400 second plate
H1500 Ink supply member
H1501 ink reservoir
H1502 Z reference plane
H1503 Third sealant
H1504 Ink supply port
H1600 Filter member
H1601 Fourth sealant
H1700 joint rubber
H1800 ink tank
H1801 needle
H1802 tube
H1900 screw
M4000 inkjet recording device
M4001 carriage
M4002 Electrical contact
K1000 Recording medium
K1001 ejected ink droplets
1A, 1B ink dot
2A, 2B image area
3 White stripes

Claims (12)

In an inkjet recording head in which a plurality of ejection openings for ejecting the recording liquid are arranged, and the ejection openings are arranged in a staggered manner in the ejection opening arrangement direction in which the recording element substrates are arranged at regular pitch intervals.
An end discharge port of a certain recording element substrate and an end discharge port on an adjacent side of the recording element substrate adjacent to the end discharge port side are arranged at intervals of the specified pitch in the discharge port arrangement direction. The inkjet recording head, wherein adjacent recording element substrates are arranged in a direction approaching each other by a distance a.   The distance a is caused by an air flow generated along with the discharge of the recording liquid from the discharge port group, and the droplets discharged from the end discharge ports in the discharge port arrangement direction when landing on the recording medium. 2. The ink jet recording head according to claim 1, wherein the distance a corresponds to a deviation amount, and the distance a is a sum of the deviation amounts of droplets from an end discharge port of an adjacent recording element substrate.   3. The ink jet recording head according to claim 2, wherein the amount of deviation is an amount of deviation due to a stream of liquid droplets ejected from the recording element substrate at a maximum print duty of the recording head.   The arrangement interval of the discharge ports constituting the end portion discharge port group located at both ends in the discharge port arrangement direction of each recording element substrate is the above-mentioned definition of the discharge ports constituting the central discharge port group located at the center portion in the arrangement direction 4. The ink jet recording head according to claim 1, wherein the ink jet recording head is set wider than the pitch.   The inkjet recording head according to claim 4, wherein an arrangement interval of the ejection ports constituting the end ejection port group is set to be 0.1 to 10 μm wider than the specified pitch.   The size of the liquid droplets discharged from the discharge ports constituting the end portion discharge port group located at both ends in the discharge port arrangement direction of each recording element substrate constitutes the central discharge port group located at the central portion in the arrangement direction The ink jet recording head according to claim 1, wherein the ink jet recording head is smaller than a size of a droplet discharged from a discharge port.   The ink jet recording head according to claim 6, wherein the size of the ejection ports constituting the end ejection port group is smaller than the size of the ejection ports constituting the central ejection port group. In an inkjet recording head in which a plurality of ejection openings for ejecting the recording liquid are arranged, and the ejection openings are arranged in a staggered manner in the ejection opening arrangement direction in which the recording element substrates are arranged at regular pitch intervals.
Adjacent recording element substrates have overlapping ejection port groups in a direction perpendicular to the ejection port array direction, and an end ejection port of a certain recording element substrate and a recording element adjacent to the end ejection port side Discharge ports corresponding to the end portion discharge ports on the adjacent side of the substrate are not arranged at intervals of the specified pitch in the discharge port arrangement direction, and the recording element substrates adjacent to each other by a distance a approach each other. An ink jet recording head characterized by being arranged.   The distance a is the amount of deviation of the droplets ejected from the ejection ports in the ejection port array direction when they land on the recording medium, caused by the air flow generated along with the ejection of the recording liquid from the ejection port group. The distance a corresponds to a droplet from an end discharge port of the certain recording element substrate and a droplet from the discharge port corresponding to the end discharge port of the adjacent recording element substrate. The ink jet recording head according to claim 8, wherein the sum is a sum of the deviation amounts.   The ink jet recording head according to claim 9, wherein the amount of deviation is an amount of deviation due to a stream of liquid droplets ejected from the recording element substrate at a maximum print duty of the recording head.   11. The ink jet recording head according to claim 1, wherein a prescribed pitch of the plurality of ejection openings is 42.3 μm or less. The inkjet recording head according to any one of claims 1 to 11, wherein an amount of droplets ejected from the ejection port at one time is 10 picoliters or less.

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