JP6468902B2 - Liquid discharge head, liquid discharge apparatus, and method of manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a liquid ejection head, a liquid ejection apparatus, and a method for manufacturing a liquid ejection head that suppress variations in landing positions due to liquid droplets ejected by blowing an air current to a region between the liquid ejection head and a recording medium.

  According to the ink jet recording apparatus disclosed in Patent Document 1, the vortex generated between the recording head and the recording medium is blown off by blowing an air flow toward the vortex. Thereby, the vortex is removed from the region between the recording head and the recording medium, and the airflow between the recording head and the recording medium is stabilized.

US Pat. No. 6,997,538

  However, in the ink jet recording apparatus disclosed in Patent Document 1, a relatively large flow rate is required to remove the vortex from the region between the recording head and the recording medium. When the required flow rate of the balloon is increased, the balloon generating means for generating the balloon is increased in size accordingly. Therefore, there is a possibility that the inkjet recording apparatus will be enlarged.

  Accordingly, in view of the above circumstances, the present invention provides a liquid discharge head, a liquid discharge apparatus, and a method for manufacturing a liquid discharge head, in which the flow rate of a blowout is kept small and the accuracy of the landing position at the time of liquid discharge is maintained high. The purpose is to provide.

The present invention is a liquid ejection head that includes an ejection port and is capable of ejecting liquid from the ejection port to a medium while performing relative movement between the ejection port and the relative to the medium rather than the ejection port. Arranged on the front side in the moving direction of movement, and protruding from the discharge port forming surface on which the discharge port is formed toward the medium, and on the front side in the moving direction from the protruding portion, A blowout port for blowing out gas in a region between the discharge port and the medium is provided.

  According to the present invention, even when an air flow having a small flow rate is blown, variation in landing position deviation along the column direction of the discharge port array in the liquid droplets discharged from the discharge ports can be suppressed to a minimum. Accordingly, it is possible to reduce the size of the liquid discharge head and the liquid discharge apparatus, and it is possible to land droplets on a desired position with high accuracy.

1 is a perspective view illustrating an ink jet recording apparatus according to a first embodiment of the present invention. 1A is a plan view of a recording head disposed in the ink jet recording apparatus of FIG. 1 as viewed from the recording medium side, and FIG. 2B is a cross-sectional view of the periphery of the ejection opening of the recording head as viewed from the side. FIG. 5 is a cross-sectional view of the periphery of the ejection port in the recording head of the comparative example as viewed from the side, (a) is a form without a blowout, (b), (c) is a form with a blowout, and (d), ( e) It is sectional drawing shown about the form in case a balloon is weak. FIGS. 3A and 3B are cross-sectional views of the recording head when recording is performed while blowing by the recording head of FIG. 2, in which FIG. 3A is a form in which the blowing port is farther from the ejection port than the protruding portion, and FIG. It is sectional drawing about the form which has a blower outlet in the position nearer than a discharge outlet. FIG. 4 is a cross-sectional view of the periphery of the ejection port as viewed from the side, showing vortices and maximum vortex core diameters that are generated when ink droplets are ejected by a recording head in which no protrusions and no ejection ports are formed. FIG. 6 is a perspective view of a discharge port forming surface in a recording head shown as a modification of the recording head in FIG. 2. FIG. 3 is a side view of the periphery of a protrusion when the discharge port forming surface of the recording head of FIG. (A) is the top view which looked at the recording head arrange | positioned at the inkjet recording device which concerns on 2nd Embodiment of this invention from the recording medium side, (b) is the cross section which looked at the discharge outlet periphery of the recording head from the side surface FIG. FIG. 6 is a cross-sectional view of the periphery of a discharge port of a recording head arranged in an ink jet recording apparatus according to a third embodiment of the present invention, viewed from the side. (A) is the top view which looked at the recording head arrange | positioned at the inkjet recording device which concerns on 4th Embodiment of this invention from the recording medium side, (b) is the cross section which looked at the discharge outlet periphery of the recording head from the side surface FIG. FIG. 10 is a cross-sectional view of a periphery of an ejection port of a recording head arranged in an ink jet recording apparatus according to a fifth embodiment of the present invention as viewed from the side.

  Hereinafter, a liquid discharge head according to an embodiment of the present invention and a liquid discharge apparatus including the liquid discharge head will be described with reference to the drawings.

(First embodiment)
First, a configuration of a recording head as a liquid ejection head according to a first embodiment of the present invention and an ink jet recording apparatus as a liquid ejection apparatus including the recording head will be described. FIG. 1 is a perspective view showing the outline of the configuration of the main part of the inkjet recording apparatus 1 according to the first embodiment of the present invention. As shown in FIG. 1, the ink jet recording apparatus 1 performs recording by discharging a liquid such as ink from a recording head 3 onto a recording medium. The recording head 3 has a plurality of ejection openings for ejecting ink. A driving force generated by a carriage motor (not shown) is transmitted from a transmission mechanism to the carriage 2 on which the recording head 3 is mounted, and the carriage 2 is reciprocated.

  A recording head 3 is mounted on the carriage 2 of the ink jet recording apparatus 1. The carriage 2 is equipped with a recording head 3 and an ink tank 6 for storing ink to be supplied to the recording head 3. The ink tank 6 is detachably mounted on the carriage 2. The recording head 3 is configured to be supplied with ink from each of the three ink tanks 6. The recording head 3 and the ink tank 6 may be integrally formed for each color to constitute an ink cartridge.

  The ink jet recording apparatus 1 shown in FIG. 1 is capable of color recording. For this purpose, the carriage 2 is equipped with three ink tanks. These three ink tanks can be attached and detached independently. Ink of each color is supplied to one recording head 3 from three ink tanks.

  The carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 performs recording by selectively ejecting ink from the plurality of ejection ports 4 by applying energy according to a recording signal.

  The recording head 3 of the present embodiment includes a substrate on which an electrothermal conversion element (not shown) is disposed, and an orifice plate 5 in which the discharge ports 4 are formed. A surface of the orifice plate 5 facing the recording medium is configured as an ejection port forming surface 8 of the recording head 3. A semiconductor element such as a switching transistor for selectively driving the electrothermal conversion element is disposed on the substrate. And the liquid chamber which can store the ink as a liquid between them is defined by joining a board | substrate and the orifice plate 5 between them. Further, an ink supply port for supplying ink to the recording head 3 is formed on the substrate so as to communicate with the liquid chamber. Ink is supplied from the ink tank 6 to the recording head 3 through the ink supply port.

  The recording head 3 of this embodiment includes an electrothermal converter for generating thermal energy as a semiconductor element, and converts the electric energy applied to the electrothermal converter into thermal energy. Then, film boiling occurs in the ink by applying the thermal energy to the ink, and the ink is ejected from the ejection port 4 by utilizing the pressure change caused by the growth and contraction of the bubbles generated thereby. This electrothermal transducer is provided corresponding to each of the ejection ports 4, and ink is ejected from the corresponding ejection port 4 by applying a pulse voltage to the corresponding electrothermal transducer according to the recording signal. In the present embodiment, an electrothermal conversion element is used as an element that imparts energy to ink in a liquid chamber in order to eject droplets, but the present invention is not limited to this. Other elements such as a piezo element may be used as an element for discharging liquid from the discharge port 4.

  As shown in FIG. 1, the carriage 2 is connected to a part of a driving belt 7 of a transmission mechanism that transmits a driving force of a carriage motor. Accordingly, the carriage 2 is guided and supported so as to be slidable in the direction of arrow A along the guide shaft 13. The carriage 2 on which the recording head 3 is mounted is reciprocated by the driving force of the carriage motor. At the same time, a recording signal is given to the recording head 3 and ink is ejected onto the recording medium. Accordingly, the carriage 2 reciprocates in the main scanning direction that intersects the conveyance direction in which the recording medium is conveyed along the guide shaft 13 by forward and reverse rotations of the carriage motor. Further, a scale (not shown) is provided for indicating the position of the carriage 2 along the moving direction of the carriage 2 (arrow A direction). As described above, it has scanning means for scanning the carriage 2 on which the recording head 3 is mounted by reciprocating in the main scanning direction. Recording is performed on the recording medium P by ejecting ink droplets while the recording head scans the scanning unit. Further, the recording apparatus 1 is provided with a platen facing the discharge port forming surface on which the discharge ports of the recording head 3 are formed.

  Further, the ink jet recording apparatus 1 includes a transport roller 14 that is driven by a transport motor (not shown) to transport the recording medium P. The inkjet recording apparatus 1 is connected to a pinch roller 15 that contacts the recording medium P with the conveyance roller 14 by a spring (not illustrated), a pinch roller holder (not illustrated) that rotatably supports the pinch roller 15, and the conveyance roller 14. In addition, a conveyance roller gear (not shown) is included. Then, the transport roller 14 is driven by the rotation of the transport motor transmitted to the transport roller gear via the intermediate gear. As described above, the ink jet recording apparatus 1 includes a transport unit that transports the recording medium.

  Further, the ink jet recording apparatus 1 is provided with a cap 226 that caps the ejection port of the recording head 3 and can receive the ink ejected from the recording head 3. Preliminary ejection with pigment ink is performed with the cap 226 capping the ejection port of the recording head 3, and the ink ejected by the preliminary ejection with the pigment ink can be collected by sucking the ink in the cap. Is possible. Further, a platen preliminary discharge position home 224 and a platen preliminary discharge position away 225 that can receive ink discharged when preliminary discharge is performed on the platen are arranged outside the recording medium P in FIG.

  2A and 2B show the recording head 3 mounted on the carriage 2 of the ink jet recording apparatus 1 of the present embodiment. FIG. 2A is a plan view of the ejection port forming surface on which the ejection ports 4 are formed in the recording head 3 as viewed from the platen side, and FIG. 2B shows a portion around the ejection ports of the liquid ejection head. It is sectional drawing shown.

  As shown in FIGS. 2A and 2B, in the recording head of this embodiment, a plurality of ejection openings for ejecting ink are arranged in one recording head, and the plurality of ejection openings are arranged in a row. The discharge port array 9 is formed in the arrangement. In the present embodiment, a plurality of ejection port arrays 9 having a plurality of ejection ports are arranged, and three ejection port arrays 9 are formed in the recording head 3 corresponding to the number of three ink tanks 6. ing.

  The recording head 3 is formed with a blowout port 10 through which airflow can be blown out. In the present embodiment, the outlet 10 is formed on the discharge port forming surface 8. The blowout ports 10 are formed corresponding to the respective three discharge port rows 9, and the respective blowout ports 10 are formed on the rear side in the recording head scanning direction of the corresponding discharge port rows 9. . That is, the air outlet 10 is disposed on the front side in the moving direction of the relative movement with respect to the recording medium, relative to the ejection port 4 in the recording head 3. The blowout port 10 is formed to extend in a direction parallel to the arrangement direction in which the discharge port arrays 9 are arranged. The blowout ports 10 are formed longer than the discharge port array 9 so as to cover the entire discharge port array 9 on the front side in the recording head scanning direction along the arrangement direction of the discharge port arrays 9. .

  The ink jet recording apparatus 1 includes a blowing mechanism that supplies gas for blowing to the blowing port 10 in order to blow gas from the blowing port 10. In the present embodiment, air is blown out from the outlet 10.

  A supply device 30 (FIG. 4A) that supplies air to the outlet 10 for blowing used in the inkjet recording apparatus 1 of the present embodiment will be described. The blowout port 10 is connected to a supply device 30 through a supply hose 31 connected to the recording head 3. In the present embodiment, the supply device 30 includes a compressor, a gas reservoir, a valve, and the like so that an airflow having a desired flow rate can be stably supplied to the outlet 10. In the present embodiment, the supply device 30 is attached to the main body side of the inkjet recording apparatus 1. However, the present invention is not limited to this, and the supply device 30 may be attached to the recording head. Further, a gas such as air may be supplied to the outlet 10 of the recording head 3 from a separate supply device installed outside the inkjet recording apparatus 1.

  In addition, although the said embodiment demonstrated the case where the supply apparatus 30 provided with the compressor was used, this invention is not limited to this. Other configurations may be used as a supply device for blowing. For example, as another configuration of the supply device, a fan that supplies air toward the air outlet 10 may be used.

  In the recording head 3 of the present embodiment, the ejection port forming surface 8 of the recording head 3 is provided with a protruding portion (projecting portion) 11 that projects from the ejection port forming surface 8 toward the recording medium. As shown in FIGS. 2A and 2B, the protrusion 11 is formed on the discharge port forming surface 8 of the orifice plate 5 so as to extend in parallel with the direction in which the discharge port array 9 extends. Yes.

  The protrusion 11 is formed so as to be positioned ahead of the ejection port 4 in the scanning direction of the recording head 3. Further, the blowout port 10 is formed so as to be positioned in front of the protruding portion 11 in the scanning direction. Therefore, the protrusion 11 is formed so as to be sandwiched between the discharge port 4 and the blowout port 10 along the scanning direction. The protrusion 11 is formed longer than the ejection port array 9 so as to cover the ejection port array 9 along the arrangement direction of the ejection port array 9 over the entire front side in the recording head scanning direction.

  Recording is performed by ejecting ink droplets by the recording head having such a configuration. Since the ink jet recording apparatus is a serial scan method, recording is performed on the recording medium by ejecting ink droplets from the ejection ports toward the recording medium while the recording head performs scanning. In this embodiment, the ink jet recording apparatus 1 performs recording by one-way recording in which recording is performed only by movement in either the forward direction or the backward direction of the reciprocating movement by the recording head 3. ing. That is, the ink jet recording apparatus 1 ejects ink droplets from the ejection port 4 of the recording head 3 only by reciprocal movement by the recording head 3, either forward movement or backward movement. doing. The recording head 3 shown in FIGS. 2A and 2B performs recording by ejecting ink droplets from the ejection port 4 only when the recording head 3 moves in the A direction.

  When ink droplets are ejected from the ejection port 4, the ink droplets fly toward the recording medium while pulling the surrounding air between the recording head 3 and the recording medium, thereby causing a downward flow in the vertical direction. . Further, the downward air flow in the vertical direction collides with the recording medium and is reflected to generate an upward air flow. Further, when ink droplets are ejected from the ejection ports 4 of the recording head 3 for recording, the recording head 3 scans along the main scanning direction, and hence the ejection port forming surface 8 of the recording head 3. An air flow along the scanning direction is generated in a region between the recording medium and the recording medium. In this way, the recording head 3 moves relative to the recording medium by scanning the recording head 3 or conveying the recording medium, so that the recording head 3 and the recording medium are moved in a direction parallel to the recording medium. Air flow is generated.

  Once the air flow formed downward in the vertical direction by being pulled by the ink droplet is reflected and wound up, it receives a horizontal airflow due to the relative movement between the recording head 3 and the recording medium. A vortex occurs between the recording medium. In this embodiment, a vortex is generated in front of the ejection port 4 in the scanning direction between the recording head 3 and the recording medium. As described above, the air flow parallel to the recording medium generated by the relative movement between the recording head 3 and the recording medium and the vertical air flow generated by the discharge of the droplets cause the discharge port array 9 to discharge forward in the scanning direction. A cylindrical vortex having a central axis extending along a direction parallel to the arrangement direction of the outlet rows 9 is generated. When this vortex is unstable, the amount of ink droplets that are caused to flow by the vortex differs along the direction in which the ejection port arrays are arranged. Therefore, the amount of deviation of the landing position of the ink droplets varies along the arrangement direction of the ejection port arrays. For this reason, there is a possibility that shading unevenness called “wind pattern” occurs on the recorded image.

  FIG. 3A shows, as a comparative example, the airflow in the region between the ejection port forming surface and the recording medium in the recording head without the air outlet 10 and the protrusion 11. As shown in FIG. 3A, when droplets are ejected from the ejection port, an airflow in the direction from the ejection port toward the recording medium is generated, and an airflow in the direction reflecting and rising from the recording medium is generated. . The recording head moves in the direction of arrow B when ejecting ink droplets. For this reason, as shown in FIG. 3A, a relatively large vortex 20 is formed ahead of the droplet ejected from the ejection port in the direction of arrow B, which is the scanning direction of the recording head.

  Further, in FIG. 3B, as another comparative example, a protrusion is not formed, and the position on the discharge port forming surface is ahead of the position of the discharge port discharging ink droplets in the scanning direction. An air flow in a state where an air flow is blown toward the recording medium will be described. In this comparative example, since the airflow is blown out toward the recording medium from the position in the scanning direction relative to the position of the discharge port, the vortex 20 is pressed toward the recording medium by the airflow, and the vortex 20 becomes small. It is suppressed. As a result, it is possible to prevent the amount of deviation of the landing position of the droplets from being unstable due to the unstable vortex 20 and to prevent the quality of the recorded image from deteriorating.

  However, in the comparative example shown in FIG. 3 (b), in order to reduce the unstable vortex 20, a relatively large flow rate of blowout is required. In order to blow out a large amount of airflow, there is a possibility that the configuration of the supply device 30 that supplies air to the blowout port for blowing out increases in size. Further, since the flow rate of the blowout is large, as shown in FIG. 3C, the ink droplets ejected from the ejection port by the blowout may be caused to flow by the blowout, thereby causing the landing position deviation of the ink droplets to occur. There is. On the other hand, if the flow rate of the blowout is insufficient, the unstable vortex 20 can be reduced as shown in FIGS. 3D and 3E even if the blowout is performed from the blowout port toward the vortex. It may not be possible. FIG. 3D shows the relationship between the ejection port formation surface of the recording head and the recording medium when the flow rate of the ejection from the ejection port is insufficient when the ejection port is formed at a position relatively far from the ejection port. It shows about the airflow of the area between. FIG. 3E shows the relationship between the ejection port forming surface of the recording head and the recording medium when the flow rate of the ejection from the ejection port is insufficient when the ejection port is formed at a position relatively close to the ejection port. It shows about the airflow of the area between. In such a case, the amount of deviation of the landing positions along the arrangement direction of the ejection port arrays is not constant, and the quality of the recorded image may be deteriorated.

  On the other hand, in the present embodiment, as shown in FIG. 4A, the blowout port 10 is formed on the discharge port forming surface 8 of the recording head 3, and the protrusion 11 is formed. Since the protrusion 11 is formed on the ejection port forming surface 8 of the recording head 3, even if droplets are ejected from the ejection port 4 and the vortex 20 is formed in front of the ejection port 4 in the recording head scanning direction. The protrusion 11 acts as a resistance against the vortex 20. Therefore, the vortex 20 is reduced and the vortex 20 is weakened. When the protrusion 11 is provided on the ejection port forming surface 8 of the recording head 3, the distance from the recording medium to the wall surface on the recording head 3 side in the region where the vortex 20 is formed compared to the case where the protrusion 11 is not provided. Can be shortened. When there is no protrusion 11, the vortex 20 generated by ejecting ink droplets is generated in a size that fits perfectly in the region from the recording medium to the ejection port forming surface 8 of the recording head 3. In the present embodiment, since the protrusion 11 is formed on the ejection port forming surface 8 of the recording head 3, the vortex 20 is generated in a region between the protrusion 11 and the recording medium. In the region where the vortex 20 is generated, the protrusion 11 is formed on the ejection port forming surface 8 of the recording head 3, so the height of the region where the vortex 20 is generated is reduced by the amount of the protrusion 11. . Therefore, the diameter of the vortex 20 generated there is kept small. Thereby, the vortex 20 can be kept at a certain strength or size.

  Further, in the present embodiment, since the blowout port 10 is formed on the discharge port forming surface 8 of the recording head 3, the airflow can be blown out from the blowout port 10 toward the region where the vortex 20 is formed. . Therefore, by pressing the vortex 20 in the direction toward the recording medium by blowing, the vortex 20 weakened to a certain level or less can be further reduced. Thereby, the influence of the vortex 20 on the ink droplet can be further reduced. Since the strength and size of the vortex 20 can be sufficiently reduced, it is possible to prevent the amount of deviation of the landing positions of the droplets from being unstable along the arrangement direction of the ejection port array due to the unstable vortex 20. It is possible to prevent the quality of the recorded image from being lowered. Thereby, the quality of the recorded image can be maintained high.

  Further, when blowing out from the outlet 10 in order to reduce the strength / size of the vortex 20 by blowing out, the vortex 20 is already kept at a certain level of strength / size by the protrusion 11. . Therefore, it is possible to reduce the flow rate of the blowout required to keep the vortex 20 small. Since the flow rate of the blowout can be reduced, the configuration of the supply device 30 that supplies the blowout air to the blowout port 10 can be simplified. Since the configuration of the supply device 30 can be simplified, the inkjet recording device 1 can be reduced in size. In addition, the manufacturing cost of the inkjet recording apparatus 1 can be reduced. Further, since the flow rate of the blowout can be reduced, it is possible to suppress the ink droplets discharged from the discharge ports 4 from being discharged by the blowout during recording. As a result, it is possible to prevent the landing positions of the ink droplets from shifting and the quality of the recorded image from deteriorating.

  Next, the structure of a suitable blowing and a protrusion part is demonstrated. Let x be the distance between the protrusion 11 and the discharge port 4 (FIG. 2B). Since the protrusion 11 is formed for the purpose of suppressing the growth of the vortex 20, it is required that the influence of the protrusion 11 on the airflow reaches the vortex 20. Therefore, the distance x between the protrusion 11 and the center of the discharge port 4 is configured such that the protrusion 11 is located in the range inside the maximum vortex core diameter D with the discharge port 4 as the center. desirable.

  In the present embodiment, the discharge port 4 is formed in a circular shape, but the present invention is not limited to this. A discharge port having a shape other than a circular cross section along a plane parallel to the recording medium may be employed. In that case, the distance x between the protrusion 11 and the center of the discharge port 4 may be x as the distance between the protrusion 11 and the position of the center of gravity of the cross section of the discharge port. That is, the distance x between the protrusion 11 and the center of the discharge port 4 is the distance between the protrusion 11 and the position of the center of gravity of the cross section along the plane parallel to the discharge port forming surface 8 in the discharge port 4. May be x.

  Here, the maximum vortex core diameter D is the maximum value of the diameter of a vortex generated in front of the ejection port array 9 in the scanning direction, as shown in FIG. FIG. 5 illustrates the vortex and the maximum vortex core diameter that are generated when an ink droplet is ejected from a recording head in which the protrusion 11 and the outlet 10 are not formed. FIG. 5 is a cross-sectional view of the periphery of the ejection port as viewed from the side in a recording head in which the protrusion 11 and the blowout port 10 are not formed. The protrusion 11 is formed for the purpose of reducing and weakening the generated vortex 20. Therefore, the protrusion 11 needs to be arranged at a position where the vortex 20 is formed. In order to reduce and weaken the vortex 20 at the position where the vortex 20 is formed, the protrusion 11 is required to be disposed within the range of the maximum vortex core diameter D of the vortex generated from the center of the discharge port 4. . By arranging the protrusion 11 in this way, the protrusion 11 can be involved in the generated vortex 20, and the vortex 20 can be reduced and weakened. Further, if the protrusion 11 is arranged at a position where a vortex is formed when ink is ejected by a recording head without the protrusion 11, the vortex at that time can be reduced and weakened. . Therefore, the protrusion 11 is required to be disposed in a range from the center position of the discharge port 4 to a position away from the maximum vortex core diameter of the vortex when the protrusion 11 is not formed.

  The maximum vortex core diameter depends on the ejection speed and droplet formation of the droplets ejected from the recording head, and thus cannot be determined unconditionally. However, the maximum vortex core diameter is about 600 μm under the recording conditions without protrusions. The discharge port-projection end distance x where the improvement effect just starts to appear and the maximum vortex core diameter of the vortex caused by the discharge are approximately the same. That is, if the projection is formed on the recording head, the projection is provided at a position approximately within the maximum vortex core diameter from the center position of the ejection port, thereby suppressing the vortex and suppressing variations in the ink droplet landing position due to the airflow. be able to. As described above, the protrusion of the present embodiment is disposed at a position within the maximum vortex core diameter of the vortex formed when the ink is discharged when there is no protrusion in the distance from the center of the discharge port. As a result, the air flow generated by the ejection of the ink can be reduced. Therefore, it is preferable that the protrusion is disposed at a position within 600 μm from the center of the discharge port.

  The length L in the arrangement direction of the ejection port array in the projection 11 (FIG. 2A) is formed for the purpose of suppressing the vortex 20 generated by the droplets ejected from the ejection port 4 by the projection 11. Therefore, it is desirable that the vortex 20 is formed so as to cover the range where the vortex 20 is generated. That is, it is desirable that the protrusion 11 has a length that covers the ejection port array 9 in the extending direction. Desirably, the length along the arrangement direction of the ejection port array 9 in the protrusion 11 is preferably longer than the ejection port array 9.

  When the height h (FIG. 2B) of the protrusion 11 is 20 μm, 50 μm, 100 μm, 200 μm, and 300 μm, the blowing required for blowing out from the outlet 10 as the protrusion height h increases. It has been confirmed that the flow rate is decreasing. That is, by setting the height h of the protrusion 11 to about 20 to 50 μm or more, there is an effect of suppressing the influence of the vortex 20 generated by the airflow of the ejected droplets on the ink droplets. It is preferable that the length from the ejection port forming surface 8 in the protrusion 11 to the portion most protruding toward the recording medium is 20 μm or more.

  Even if the width d (FIG. 2 (b)) in the direction orthogonal to the direction in which the ejection port array 9 extends in the protrusion 11 is changed to 42.4 μm, 127.2 μm, and 254.8 μm, It has been confirmed that the required flow rate in the blowout does not change much. That is, if the protrusion 11 having a width of 42 μm or more is provided in front of the ejection port 4 in the scanning direction, the effect on the ink droplet due to the vortex generated by the airflow of the ejected droplet is reduced. . Moreover, if it has a width of 42 μm or more, it can be said that the width of the protrusion 11 hardly affects the image quality. That is, it is preferable that the length of the protrusion 11 in the recording head 3 along the moving direction of the relative movement with respect to the recording medium is 42 μm or more.

  In addition, as FIG. 6 shows, the projection part 11 may be formed discontinuously along the arrangement direction of a discharge port row | line | column. A plurality of projections 11 extending in the arrangement direction of the discharge port arrays 9 may be formed along the arrangement direction of the discharge port arrays 9, and a gap m may be formed between the plurality of projections 11. . In this case, the gap m formed between the protrusions 11 is desirably 20 μm or less. By providing the gap m between the protrusions 11 in this way, the ink overflowing on the ejection port forming surface can be held in the gap m between the protrusions by capillary force. Accordingly, it is possible to prevent ink overflowing on the discharge port forming surface 8 from collecting and dropping onto the recording surface of the recording medium, and to prevent the recording medium from being soiled.

  In addition, if the interval m between the protrusions 11 is excessively large, the protrusions 11 are not formed in the portion of the interval m between the protrusions 11, so that the vortex 20 cannot be reduced by the protrusions 11. Therefore, a relatively large vortex 20 is formed in the portion of the interval m between the protrusions 11 without being suppressed. On the other hand, in the portion where the protrusion 11 is formed, the vortex 20 is kept small by the protrusion 11. As a result, the size of the vortex 20 varies along the arrangement direction of the discharge port arrays 9. Since a non-uniform vortex intensity distribution occurs in the direction in which the ejection port array 9 is arranged, the amount of deviation in the landing position of the ink droplets ejected from the ejection port 4 due to the vortex varies along the direction in which the ejection port array 9 is arranged. Occurs. Since the deviation amount of the landing position of the ink droplet varies between the portion where the protrusion 11 is formed and the portion of the gap m between the protrusions 11, there is a possibility that the image quality of the recorded image is deteriorated. is there. In this way, if the gap m is formed larger than the predetermined length, there is a possibility that the quality of the recorded image is deteriorated. Therefore, the length of the gap m between the protrusions 11 is equal to or less than the predetermined length. Preferably there is. In the present embodiment, the length along the arrangement direction of the ejection port array 9 in the gap m between the protrusions is preferably 20 μm or less.

  The material for forming the protrusion 11 is not particularly limited. However, when the discharge port forming surface 8 is wiped in order to clean the discharge port forming surface 8, it is required that the protrusion 11 does not become an obstacle. Further, when the protrusion 11 rubs against the recording medium, it is required to prevent the recording medium held between the rollers from being displaced in the conveyance direction of the recording medium. For this reason, it is desirable that the protrusion 11 be formed of a soft material that does not fall down as the recording head 3 scans. By forming the projection 11 with a soft material, as shown in FIG. 7, when the blade or the like wipes the discharge port forming surface 8, the projection 11 is less damaged by the blade. FIG. 7 is a side view of the periphery of the protrusion 11 when wiping is performed on the discharge port forming surface 8 by a blade. FIG. 7 shows the protrusion 11 formed with a relatively long length in the direction from the discharge port forming surface 8 toward the recording medium so as to be easily deformed. When the projection and the recording medium are rubbed, the projection itself is deformed, so that it is possible to suppress a shift in the recording medium conveyance direction at the position of the recording medium held between the rollers.

  In addition, although the projection part 11 mentioned above is the square pillar-shaped projection part 11 which a cross section has a rectangular shape, you may have shapes other than a square pillar shape. The same effect can be obtained even when the protruding portion 11 is a protruding portion having a shape such as a cylindrical column or a polygonal column other than a square column. Further, in the above-described embodiment, the protrusion 11 is in close contact with the discharge port forming surface 8 of the orifice plate 5 in the entire arrangement direction of the discharge port array 9, and the protrusion is formed over the entire discharge port array 9. It is assumed that there is substantially no gap between 11 and the discharge port forming surface 8. However, the present invention is not limited to this. For example, the projection 11 and the discharge port forming surface 8 of the orifice plate 5 are in contact with each other only at both ends in the longitudinal direction of the projection 11, and a gap is formed between the other portions of the projection 11 and the discharge port forming surface 8. The structure which has may be sufficient.

  Next, the balloon from the outlet will be described. Here, a preferable distance between the outlet and the outlet will be described. Since the blowout has the effect of suppressing the vortex, the blowout must be able to act on the vortex. Since the airflow blown out from the outlet flows behind the outlet, the effect of the present invention is recognized even if the distance from the outlet row 9 to the outlet 10 is longer than the maximum vortex core diameter. The effect of the present invention can be obtained if the distance from the discharge port array 9 to the blowout port 10 is approximately within the distance between the recording medium and the orifice plate 5. For this reason, it is desirable that the blowout port 10 be arranged so that the distance from the discharge port array 9 is within the distance between the recording medium and the discharge port forming surface 8 of the orifice plate 5.

  Next, the positional relationship between the protrusion and the outlet will be described. The closer the protrusion 11 is to the ejection port array, the smaller the flow rate required to suppress the vortex, whereas the distance between the ejection port 10 and the ejection port array 9 becomes shorter to some extent. It has only the same effect on vortex suppression. Therefore, it is desirable that the distance from the discharge port array 9 to the protrusion 11 is shorter than the distance from the discharge port array 9 to the blowing port 10. In addition, although the said embodiment demonstrated the form in which the projection part 11 is arrange | positioned in the position near the discharge outlet row | line | column 9 rather than the blowing outlet 10, this invention is not limited to this. As shown in FIG. 4B, the air outlet 10 may be formed at a position closer to the protrusion 11.

  In the present embodiment, a case where the recording head 3 is applied to a serial scanning type recording apparatus that performs recording while scanning is shown. However, the present invention may be applied to a so-called full-line type ink jet recording apparatus that performs recording by ejecting ink from a long recording head without scanning the recording head. In this case, the protrusion 11 may be provided upstream of the ejection port array 9 in the recording medium conveyance direction. By doing so, an airflow in the direction from the recording head to the recording medium when ink droplets are ejected, an airflow reflected by the recording medium and rising, and a vortex generated by the airflow generated by the recording medium being conveyed The effect on ink droplets is suppressed.

(Second Embodiment)
Next, a second embodiment for carrying out the present invention will be described. The description of the same configuration as in the first embodiment will be omitted, and only different parts will be described.

  The basic configuration of the ink jet recording apparatus according to the second embodiment is as shown in the first embodiment. However, in the recording head 3a of the second embodiment, as shown in FIG. 8, the first embodiment is that the protrusion 11 and the air outlet 10 are arranged both in front and rear in the scanning direction of the recording head. Different from the recording head of the form. FIG. 8A is a plan view of the ejection port forming surface in which the ejection ports 4 are formed in the recording head, as viewed from the platen side, and FIG. 8B shows a portion around the ejection port of the recording head. It is sectional drawing.

  In the second embodiment, the ink jet recording apparatus is configured to be able to perform bidirectional recording in which recording is performed by both movement in the forward direction and movement in the backward direction in scanning of the recording head 3. As described above, even when bidirectional recording is performed, according to the recording head 3a of this embodiment, both the forward movement and the backward movement are both ahead of the ejection port 4 in the scanning direction. The protrusion 11 and the outlet 10 can be arranged.

  In the moving direction of the recording head 3a shown in FIG. 8, scanning in the direction of arrow C is set as scanning in the forward direction, and scanning in the direction of arrow D is set as scanning in the backward direction. At the time of scanning in the forward direction, the protrusion 11a is arranged in front of each ejection port array in the scanning direction. Further, the blowout port 10a is arranged in front of the scanning direction of the discharge port array located in the foremost position in the C direction. Further, when scanning in the backward direction in the D direction, the protrusion 11b is disposed in front of the respective ejection port arrays in the scanning direction. Further, the blowout port 10b is disposed in front of the scanning direction of the discharge port array positioned in the forefront in the D direction. Further, the blowout port 10c is arranged at a position sandwiched between the ejection port arrays along the scanning direction by the recording head 3a. The outlet 10c is positioned forward of the ejection port array 9a in the scanning direction in both the scanning in the C direction and the scanning in the D direction. Therefore, the outlet 10c is involved in the suppression of vortices in both scanning in the C direction and scanning in the D direction.

  When scanning in the C direction, the protrusion 11a is disposed in front of the ejection port array 9a in the scanning direction, so that the vortex can be reduced by the protrusion 11a. Therefore, the vortex can be made sufficiently small by blowing out with a small flow rate. Further, when scanning in the D direction, since the protrusion 11b is arranged in front of the ejection port array 9a in the scanning direction, the vortex can be reduced by the protrusion 11b. Therefore, the vortex can be made sufficiently small by blowing out with a small flow rate.

  Therefore, in both the scanning in the C direction and the scanning in the D direction, the vortex generated by the protrusions 11a and 11b can be suppressed to a certain level of strength and size. Therefore, the vortex can be made sufficiently small by blowing out with a small flow rate from the blowing ports 10a, 10b, 10c. Thereby, in both the scanning in the C direction and the scanning in the D direction, the influence of the vortex on the recorded image can be suppressed, and the quality of the recorded image can be maintained high.

  Note that the protrusions and the blown airflow installed rearward with respect to the traveling direction of the recording head 3a do not act on the droplets ejected from the ejection port array 9a, thereby causing the landing position to shift. There is no. Therefore, in any case of scanning in the C direction and scanning in the D direction, the blowing may be performed from all the blowing ports 10a, 10b, and 10c. For example, while the recording head 3a is scanning in the C direction, the blowing port 10b may be blowing out, or while the recording head 3a is scanning in the D direction, from the blowing port 10a. A speech bubble may be performed. Also, in an ink jet recording apparatus that performs one-way recording in which recording is performed only in either the forward direction or the backward direction, there are blowout ports and protrusions on both the front and rear in the scanning direction of the discharge port array 9a. A formed recording head may be employed.

(Third embodiment)
Next, a third embodiment for carrying out the present invention will be described. The description of the same configuration as in the first and second embodiments will be omitted, and only different parts will be described.

  As shown in FIG. 9, the recording head 3b of the third embodiment is different from the recording heads of the first embodiment and the second embodiment in that the air outlet 10d is formed in the protrusion 11c. In the present embodiment, the air outlet 10d is formed at the tip of the protrusion 11c on the recording medium side. A flow path 12 that communicates with the blowout port 10d and supplies airflow to the blowout port 10d is formed inside the protrusion 11c. The flow path 12 communicating with the blowing port 10d is provided so as to penetrate the protrusion 11c in the direction from the discharge port forming surface 8 of the recording head 3b toward the recording medium.

  Thus, in this embodiment, since the blowing outlet 10d is opened by the projection part 11c, a structure can be simplified compared with the structure in which the blowing outlet 10d and the projection part 11c are formed separately. . Since the configuration is simplified compared to the configuration in which the outlet 10d and the protrusion 11c are separately formed, the recording head 3b can be reduced in size, and the inkjet recording apparatus 1 can be reduced in size. In addition, the manufacturing cost of the inkjet recording apparatus 1 can be reduced.

  In the recording head of the first embodiment or the second embodiment, it is necessary to secure a space for disposing both the blowout port and the protrusion on the discharge port forming surface, which may increase the size of the recording head. is there. On the other hand, in the recording head 3b of the third embodiment, the required space can be reduced by performing the blowing from the blowing port 10d provided in the protrusion 11c. Thereby, the recording head 3b can be reduced in size.

(Fourth embodiment)
Next, a fourth embodiment for carrying out the present invention will be described. The description of the same components as those in the first to third embodiments will be omitted, and only different parts will be described. FIG. 10A is a plan view of the ejection port forming surface in which the ejection ports 4 are formed in the recording head 3c as viewed from the platen side, and FIG. 10B shows a portion around the ejection ports of the recording head 3c. It is sectional drawing shown.

  In the recording head 3c shown in FIG. 10, the ejection port arrays are arranged in the order of cyan (C), magenta (M), yellow (Y), magenta (M), and cyan (C). Here, the cyan discharge port array is 9b, the magenta discharge port array is 9c, and the yellow discharge port array is 9d. As shown in FIG. 10, the cyan discharge port array 9b and the magenta discharge port array 9c are arranged so that the discharge port array is symmetrical about the yellow discharge port array 9d. 9d is arranged on both sides. In the recording head 3c of this embodiment, the cyan ejection port array 9b is formed on the outermost side in the scanning direction of the recording head 3c, the magenta ejection port array 9c is formed on the inner side, and the yellow ejection port array is formed on the innermost side. 9d is formed. For this reason, two ejection port arrays 9c of colors other than yellow are arranged two by two, whereas only one yellow ejection port array 9b is arranged.

  Two rows of cyan discharge port arrays 9b and magenta discharge port arrays 9c are formed in the recording head 3c. For this reason, the two ejection port arrays in the ejection port arrays of the respective colors are arranged so as to be shifted from each other, whereby the resolution can be improved. In the present embodiment, by disposing the two ejection port arrays in the ejection port arrays of the respective colors with a shift of 0.5 pitch from each other, the resolution can be improved by a factor of two. The cyan discharge port arrays 9b sandwiching the yellow discharge port array 9d are arranged so as to be shifted from each other by 0.5 pitch, and the discharge port arrays 9c are arranged so as to be shifted from each other by 0.5 pitch. Has been.

  In this case, in order to match the resolution to the other ejection port arrays 9b and 9c, in the ejection port array having a relatively small number such as the yellow ejection port array 9d in which only one column is disposed, 1 A relatively large number of discharge ports are formed in the row. In the present embodiment, the yellow discharge port array 9d has twice as many discharge ports as the other discharge port arrays 9b and 9c per one discharge port array.

  In this embodiment, printing is performed by using all of the five ejection port arrays 9b, 9c, and 9d in one scan. When recording is performed using the recording head 3c of the present embodiment, the relatively small number of the arranged ejection port arrays 9d is compared with the relatively large number of the arranged ejection port arrays 9b and 9c. The number of ink ejections from the ejection port array per line increases. For this reason, in the ejection of ink from the yellow ejection port array 9d in which only one column is formed, the ejection frequency increases.

  Further, in the present embodiment, in the ink discharge from the relatively small number of yellow discharge port arrays 9d, by increasing the discharge frequency, the discharge from the ink discharge from the relatively large number of discharge port arrays 9b and 9c. Although it matches with the number of discharges, the present invention is not limited to this. Ink discharge from the relatively small number of yellow discharge port arrays 9d increases the amount of ink discharged per ink discharge, thereby discharging ink from the relatively large number of discharge port arrays 9b and 9c. You may adjust to. As the amount of ink discharged per one ink discharge increases, the proportion of dots occupied by one ink discharge increases. Thereby, the ratio of the dot which occupies for a unit area is arrange | equalized between the ejection port row | line with few numbers, and the ejection port row | line with many numbers. In that case, the number of ejection ports per row may be the same between a relatively large number of ejection port rows and a relatively small number of ejection port rows, and the number of ink ejections per row is The same may be used between a relatively large number of ejection port arrays and a relatively small number of ejection port arrays. In that case, the opening area of the discharge ports may be formed large in the discharge ports in the small number of discharge port arrays.

  In the present embodiment, in the small number of arranged ejection port arrays 9d, the ejection frequency in ink ejection is high, so the flow rate of airflow in the direction from the ejection port toward the recording medium when ink is ejected is large. Become. Accordingly, when ink is ejected, the vortex generated in front of the ejection direction due to the flying of the ink is larger in the ejection port array 9d having a smaller number of arranged ejection ports. It is often larger and stronger than the columns 9b and 9c.

  In such a case, since the strength and size of the vortex generated for each discharge port row are different, it may be required to control the flow rate of the blowout from the blowout port for each discharge port row. In order to reduce the variation in the landing position deviation of ink droplets caused by vortices, in order to reduce the strength and size of the vortices for all the ejection port arrays as well, the ink ejection amount and frequency for each ejection port array can be reduced. It may be required to suppress the vortex by a corresponding blowout. In such a case, there is a possibility that the ejection port array 9d with a small number of arrangements that generate a large and strong vortex may be required to emit a stronger blowout than the other ejection port arrays 9b and 9c. In that case, the difference in the flow rate of the blowout for each blowout port 10e becomes large, and it may be difficult to control the blowout.

  Therefore, in the present embodiment, since the number of the arranged nozzles is small, the protrusion 11d is provided only in the discharge port array 9d for the discharge port array 9d in which a strong vortex is generated. As described above, since the protrusions 11d are formed only on the small number of arranged discharge port arrays 9d, only the discharge port array 9d in which large and strong vortices are generated, the vortices are weakened and suppressed by the protrusions 11d. . As a result, the flow rate required for blowing can be reduced only for the small number of arranged discharge port arrays 9d.

  Since the vortex is reduced and weakened by the projection 11d only for the discharge port array 9d where a strong and large vortex is generated, the difference in the flow rate of the blowout required for each discharge port array can be reduced. Accordingly, the magnitude of the flow rate of the blowout required for each ejection port array can be made uniform among the entire ejection port arrays. As a result, the blowout flow rate can be easily controlled. When the required flow rate for each discharge port array is the same, it is only necessary to perform a constant flow rate from all the outlets, so the flow rate of the blow can be easily controlled. .

  Further, in the present embodiment, the protruding portions 11d are disposed only on the rear side and the front side in the movement direction of the relative movement with respect to the recording medium rather than the ejection port array 9d only in the fewer ejection port arrays 9d. ing. Thereby, in both the forward movement and the backward movement by the recording head 3c, the protrusion 11d can reduce and weaken the vortex. Therefore, it is possible to reduce the difference in the flow rate of the blowing required for each ejection port array in both the forward movement and the backward movement by the recording head 3c. Thereby, the magnitude | size of the flow volume of the blowing required for every discharge port row | line | column can be equalized in the whole discharge port row | line | column in both the movement to a forward direction, and the movement to a backward direction.

  In this way, the number of rows arranged for each color in the specific discharge port row (first discharge port row) is a discharge port row other than the specific discharge port row among the plurality of discharge port rows. The plurality of discharge port arrays are configured so as to be smaller than the number of columns arranged for each color. Further, only a part of the plurality of discharge port arrays is provided with a protrusion on the front side in the moving direction of the relative movement with respect to the recording medium than the discharge port array. In the present embodiment, only for the ejection port array 9d where a strong and large vortex is generated, the protrusion 11d is formed ahead of the ejection port array 9d in the scanning direction of the recording head 3c, thereby reducing the required flow rate of the blowout. Can do.

  Further, in the present embodiment, since the projections 11d are arranged on both sides in the scanning direction of the discharge port array 9d, the flow rate of the blowout required for each discharge port array is entirely aligned, and the blowout is performed for each discharge port array. It is not necessary to control the flow rate from the port 10e. Therefore, the flow rate of the blowing required for each discharge port array can be made uniform with a simple configuration. Therefore, the configuration required for controlling the flow rate of the blowout for each ejection port array can be omitted, and the configuration of the ink jet recording apparatus can be simplified. Thereby, the ink jet recording apparatus can be reduced in size, and the manufacturing cost of the ink jet recording apparatus can be reduced.

(Fifth embodiment)
Next, a fifth embodiment for carrying out the present invention will be described. The description of the same components as those in the first to fourth embodiments will be omitted, and only different parts will be described.

  In the fifth embodiment, as shown in FIG. 11, the outlet 10f that blows air into the space between the discharge port forming surface 8 and the recording medium is not formed in the orifice plate 5 of the recording head 3d. Absent. The outlet 10f is formed in a member configured as a member different from the recording head 3d, and is provided outside the recording head 3d. In the first to fourth embodiments, the blowout port is provided on the discharge port forming surface of the orifice plate in the recording head. Therefore, it is necessary to finely process the orifice plate. On the other hand, in this embodiment, since the outlet 10f is formed in another member, it is not necessary to perform fine processing on the orifice plate 5, and the manufacture of the ink jet recording apparatus having the outlet 10 is facilitated.

  As a configuration in which the outlet 10f is formed in a member different from the orifice plate 5, an air outlet duct 16 may be provided outside the recording head 3d as shown in FIG. Further, a configuration is adopted in which the space around the recording head is sealed, and the sealed air is blown by a fan or the like so that air is forcibly supplied between the discharge port forming surface and the recording medium. May be.

  Further, in the present embodiment, the form in which the outlet 10f is formed on a member different from the orifice plate 5 has been described. However, the protrusion may be formed on a member different from the orifice plate 5. As long as the vortex is formed at a position related to the formation of the vortex, the orifice plate 5 may not be formed. By doing so, the configuration of the recording head can be further simplified.

(Sixth embodiment)
Next, a sixth embodiment for carrying out the present invention will be described. The description of the same components as those in the first to fifth embodiments will be omitted, and only different parts will be described.

  There are roughly two methods for providing the protrusions in the vicinity of the discharge port array. Specifically, a method for providing a protrusion on the discharge port forming surface by laminating a layer for forming a protrusion on the discharge port forming surface, and forming a discharge port in the recording head by separately manufacturing a member for forming the protrusion. There is a method of adhering to the surface.

  When a member to be a protrusion is bonded to the discharge port forming surface of the orifice plate, it is necessary to bond the member to a predetermined position with high accuracy. If the distance between the discharge port and the protrusion in the single discharge port array varies along the arrangement direction, a difference will occur in the degree to suppress the vortex, and the distribution of the landing position may be unevenly distributed. May end up. In order to suppress vortices uniformly along the arrangement direction of the discharge port arrays, it is necessary to align the distance between the discharge ports and the protrusions in the arrangement direction of the discharge port arrays. In this case, if the respective members are bonded separately to the plurality of discharge port arrays, it is necessary to increase the mounting accuracy for each bonding of the protrusions. For this reason, it takes time to manufacture the recording head, which increases the manufacturing cost and increases the time required for manufacturing.

  Therefore, in order to manufacture a recording head in which a plurality of protrusions are formed, it is preferable to manufacture in advance a member in which all the protrusion members are integrated and affix them to the discharge port forming surface. Thereby, in the attachment of the protrusions, it is not necessary to attach each protrusion in a predetermined attachment position with high accuracy, and it is only necessary to perform the attachment once with high accuracy. Accordingly, the manufacturing process of the recording head can be simplified, the manufacturing cost of the recording head can be reduced, and the time required for manufacturing the recording head can be shortened. Moreover, it can suppress that the distance between discharge port arrays for every projection part varies. The distance between the projection and the ejection port array is kept constant over all the ejection port arrays, and variation in the positional accuracy of the attachment of the projections for each ejection port array can be suppressed. Accordingly, the influence of the vortex on the ink droplets is constant across all the ejection port arrays, and the amount of landing position deviation due to the ejected ink droplets is constant. Thereby, it is possible to suppress variation in the amount of deviation of the landing positions of the ink droplets, and it is possible to suppress deterioration in the quality of the recorded image.

  Thus, the protrusion formation member in which the protrusion part arrange | positioned for every some discharge port row | line | column was integrally formed is manufactured previously (projection part formation member manufacturing process). And a recording head may be manufactured by affixing the manufactured protrusion part formation member on the discharge port formation surface (protrusion part formation member sticking process).

  As another method of providing a projection on the ejection port forming surface of the recording head, a plate-like member is attached to the entire ejection port forming surface of the recording head, and a portion corresponding to the ejection port array of the member is laser It is possible to provide a protrusion on the discharge port forming surface by making a hole. According to this method, the protrusion can be provided at a predetermined position with higher positional accuracy. In addition, it is not necessary to increase the positional accuracy when attaching the protrusions, the manufacturing process of the recording head can be simplified, the manufacturing cost of the recording head can be reduced, and the manufacturing of the recording head can be performed. Such time can be shortened.

  Thus, a plate-shaped plate member is affixed on the discharge port formation surface (plate-shaped member affixing step). And a recording head may be manufactured by removing the part corresponding to the ejection opening in a board member (removal process).

(Other embodiments)
The liquid discharge head of the present invention can be mounted on an apparatus such as a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, or an industrial recording apparatus combined with various processing apparatuses. By using this liquid discharge head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics. Note that “recording” used in the present specification not only applies an image having a meaning such as a character or a figure to a recording medium but also an image having no meaning such as a pattern. I mean.

  Furthermore, “ink” or “liquid” is to be interpreted widely, and is applied on a recording medium to form an image, a pattern, a pattern, or the like, process the recording medium, or ink or recording medium. It shall mean the liquid that is subjected to the treatment. Here, as the treatment of the ink or the recording medium, for example, the fixing property is improved by coagulation or insolubilization of the coloring material in the ink applied to the recording medium, the recording quality or coloring property is improved, and the image durability is improved. Say that.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 3 Recording head 4 Ejection port 8 Ejection port formation surface 10 Outlet 11 Projection part 20 Vortex

Claims (18)

A liquid discharge head that includes a discharge port and is capable of discharging liquid from the discharge port to a medium while performing relative movement with the medium,
A protrusion that is disposed on the front side in the movement direction of the relative movement with respect to the medium from the discharge port and protrudes in a direction toward the medium from the discharge port forming surface on which the discharge port is formed;
A liquid ejection head , comprising: a blow-out port that is disposed on the front side in the movement direction with respect to the projecting portion and blows out gas in a region between the discharge port and the medium.   The projecting portion is located between the ejection port forming surface and the medium when the liquid is ejected from the ejection port while performing the relative movement with respect to the medium from the center of the ejection port without the projection. The liquid discharge head according to claim 1, wherein the liquid discharge head is disposed within a range of a maximum vortex core diameter of the vortex generated in the step. The protrusion is disposed at a position within 600 μm from the center of the ejection port, and the blowout port is disposed at a distance shorter than the distance between the ejection port forming surface and the medium from the center of the ejection port. The liquid discharge head according to claim 1, wherein the liquid discharge head is a liquid discharge head.   4. The liquid discharge head according to claim 1, wherein a length from the discharge port formation surface of the protrusion to a portion that protrudes most toward the medium side is 20 μm or more. 5.   5. The liquid discharge head according to claim 1, wherein a length along the moving direction of the protruding portion is 42 μm or more. 6. A plurality of the discharge ports are arranged in an arrangement direction intersecting the moving direction to form a discharge port array;
Each of the protrusion and the outlet is formed to extend in the arrangement direction ,
6. The liquid discharge head according to claim 1 , wherein in the arrangement direction, a length in which the protruding portion and the blowout port are formed is longer than a length of the discharge port array. . The liquid ejection according to claim 6 , wherein a plurality of the protrusions are formed by discontinuously disposing the protrusions in the arrangement direction, and a gap is formed between the plurality of protrusions. head. The liquid ejection head according to claim 7 , wherein the gap is 20 μm or less. 9. The liquid discharge head according to claim 1 , wherein the liquid discharge head performs relative movement with respect to the medium by moving in a direction crossing a conveyance direction in which the medium is conveyed. The protruding portion is also arranged on the rear side in the movement direction of the relative movement with respect to the medium, rather than the ejection port.
10. The liquid discharge head according to claim 1 , wherein the blowout port is disposed further to the rear side in the movement direction of the relative movement with respect to the medium than the discharge port. The liquid discharge head according to claim 1 , wherein the liquid is moved relative to the medium by being conveyed. A plurality of the discharge port arrays are formed in the movement direction ,
The protrusions of the plurality of the discharge port array in association with the portion of the discharge opening rows, the liquid ejection according to claim 6, characterized in that it is placed on the front side of the moving direction head. 13. The liquid ejection head according to claim 12 , wherein the number of ejection ports arranged in the partial ejection port array is larger than the number of ejection ports arranged in the other ejection port array. . Claim wherein the portion of the discharge port array, rather than the ejection opening array of the other unit, the ejection frequency at the time of discharging liquid is high, or, wherein the discharge amount of liquid per discharge once is large 14. A liquid discharge head according to 12 or 13 . It has a liquid discharge head that discharges liquid from the discharge port,
A liquid ejection apparatus for ejecting liquid onto a medium while performing relative movement between the liquid ejection head and the medium,
A protrusion that is disposed on the front side in the moving direction of the relative movement of the liquid discharge head with respect to the medium from the discharge port, and protrudes in a direction from the discharge port forming surface on which the discharge port is formed toward the medium;
Than the protrusion, is disposed on the front side of the moving direction, than said discharge opening is disposed on the front side in the moving direction of the relative movement medium of the liquid discharge head, the region between the discharge outlet and the medium A liquid discharge apparatus comprising: a blow-out port for blowing gas. The liquid ejection device according to claim 15 , wherein the blowout port is formed in a member different from the liquid ejection head. A plurality of ejection port arrays having a plurality of ejection ports are formed, and it is possible to eject liquid from the ejection ports to the medium while performing relative movement between the ejection ports, and for each of the ejection port arrays, than the discharge port, it is disposed on the front side of the movement direction of the relative medium relative movement, and a projection projecting from the discharge port forming surface formed of said discharge port in a direction toward the medium, than the protruding portion, wherein A liquid ejection head that is disposed on the front side in the movement direction and includes a blowout port that blows gas to a region between the discharge port and the medium,
A protrusion forming member manufacturing process for manufacturing a protrusion forming member in which the protrusion is integrally formed;
A method of manufacturing a liquid discharge head, comprising: a protruding portion forming member attaching step of attaching the protruding portion forming member manufactured in the protruding portion forming member manufacturing step to the discharge port forming surface. A plurality of ejection port arrays having a plurality of ejection ports are formed, and it is possible to eject liquid from the ejection ports to the medium while performing relative movement between the ejection ports, and for each of the ejection port arrays, than the discharge port, it is disposed on the front side of the movement direction of the relative medium relative movement, and a projection projecting from the discharge port forming surface formed of said discharge port in a direction toward the medium, than the protruding portion, wherein A liquid ejection head that is disposed on the front side in the movement direction and includes a blowout port that blows gas to a region between the discharge port and the medium,
A plate-like member attaching step of attaching a plate-like plate member to the discharge port forming surface;
And a removal step of removing a portion of the plate member corresponding to the discharge port.

Images