JP2010184405A - Liquid droplet discharge head, ink cartridge, inkjet recording device, and method for manufacturing nozzle plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle shape excellent in air bubble discharging property by making shapes of nozzle holes proper. <P>SOLUTION: In a droplet discharge head having an liquid chamber base plate having an ink liquid chamber, a nozzle plate in which the plurality of nozzle holes are arranged communicating with the ink liquid chamber, and a discharge means for discharging ink liquids in the ink liquid chamber from the nozzle holes as liquid droplets by applying pressure to the ink liquid chamber, the cross-sectional shape in the liquid chamber base plate side of the nozzle holes has an oblong shape or an oval shape relative to the arranging direction of the nozzle holes and the opening diameter along the arranging direction of the nozzle holes is smaller than the opening diameter at the ink liquid chamber side in the cross-sectional shape at the discharge side of the nozzle holes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge head that discharges ink droplets for recording, an ink cartridge, an inkjet recording apparatus, and a method for manufacturing a nozzle plate.

  In general, a droplet discharge head used in an image recording apparatus such as a printer, a facsimile, a copying apparatus, or a plotter has a nozzle plate in which a plurality of nozzle holes for discharging droplets are formed and an ink liquid that is discharged in communication with the nozzle holes. And an energy generating element for applying energy to the ink in the ink liquid chamber.

  In the droplet discharge head configured as described above, the energy generating element is driven by the recording signal, and ink droplets are discharged from the corresponding nozzle holes to form an image.

  In recent years, in such an ink jet recording apparatus, the quality of recorded images has been improved, and high-definition images equivalent to 1200 dpi have been put into practical use. In order to form such high-definition images, however, In addition to miniaturization of ejected ink droplets, high density of nozzle holes and high landing position accuracy of ink droplets are required.

  As a method for forming such fine and high-density nozzle holes, a formation method using an excimer laser has been widely known. Generally, it is a method in which an excimer laser is irradiated to a light-shielding mask on which a nozzle hole pattern is formed, and nozzle holes are formed by the transmitted beam light, and by forming a plurality of nozzle patterns as a feature, Since nozzle holes can be formed by forming a large number of nozzle holes at once or by repeating them, it is known as a construction method that is excellent in productivity as well as processing quality.

  However, as a problem of the nozzle hole formed by the excimer laser, the nozzle hole is formed to have a tapered shape from the laser beam incident side toward the discharge side, and therefore the nozzle hole has a larger diameter than the discharge port diameter. This is a problem in terms of high-density arrangement.

  Therefore, as a method for solving these problems, Patent Documents 1 to 3 propose that the shape of the nozzle hole is an ellipse or an ellipse.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses that in the formation of a nozzle hole by excimer laser, the shape of the nozzle hole is an ellipse having a perfect circle on the discharge side and a short diameter in the nozzle pitch direction on the inflow side.

  By making the inflow side into an oval shape, the inner volume of the nozzle holes is secured while increasing the arrangement density of the nozzles, so that a nozzle having high density and excellent ejection characteristics is formed. In the manufacturing method, the laser irradiation and the movement of the nozzle plate are repeated in stages in the radial direction of the ellipse.

  Further, in Patent Document 2, as in Patent Document 1, the nozzle hole discharge side is a perfect circle and the inflow side is an ellipse having a minor axis in the nozzle pitch direction. In the manufacturing method, the cross-sectional shape is continuously changed by changing the focal point of the irradiated laser beam.

  Further, Patent Document 3 discloses an elliptical nozzle substrate having a long diameter with respect to the arrangement direction of the nozzle holes, and the discharge side and the inflow side of the nozzle holes are formed with the same diameter and shape. The machine resolution in the paper feed direction is inferior to the head scanning direction, and the nozzle shape is improved to improve the image resolution in the feed direction.

  According to these, by forming the nozzle holes in the shape of an ellipse or ellipse having a minor axis in the nozzle hole arrangement direction and a major axis in a direction perpendicular thereto, it is possible to arrange the nozzle holes at a high density. In addition, by forming the nozzle holes in an oval or elliptical shape, it becomes possible to form a larger opening diameter on the long diameter side that does not affect the arrangement pitch of the nozzle holes, and the inside of the nozzle holes has a large volume. As a result, the ejection of ink droplets is stabilized.

  However, some problems remain in the nozzle configuration and the manufacturing method as disclosed in Patent Documents 1 to 3. One of the characteristics of the ink jet head is the ability to discharge bubbles generated in the ink liquid chamber. Although it is effective to dispose the nozzle hole at the end of the ink liquid chamber for the bubble discharge property of the ink liquid chamber, the conventional configuration cannot solve this problem.

  In addition, in order to form such an oval or elliptical nozzle hole, it is necessary to alternately repeat the irradiation of the laser beam and the movement of the processing stage holding the nozzle plate. It becomes long and a problem arises with respect to productivity and production cost.

  In addition, the nozzle hole is formed by alternately repeating the irradiation of the laser beam and the movement of the processing stage, so that the operation accuracy of the processing stage is required, which is a factor in complicating processing equipment and increasing costs. . Moreover, it was difficult to form an ellipse with respect to the nozzle arrangement direction.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to obtain a nozzle shape excellent in bubble discharge performance by optimizing the shape of the nozzle hole.

  In order to solve the above problems, a liquid droplet ejection head according to the present invention includes a liquid chamber substrate having an ink liquid chamber, a nozzle plate in which a plurality of nozzle holes communicating with the ink liquid chamber are arranged, and pressure applied to the ink liquid chamber. And a liquid discharge head having a discharge means for discharging the ink liquid in the ink liquid chamber as a liquid droplet from the nozzle hole, the cross-sectional shape of the nozzle hole on the liquid chamber substrate side is relative to the arrangement direction of the nozzle holes. In addition, the cross-sectional shape on the ejection side of the nozzle holes is characterized in that the opening diameter along the nozzle hole arrangement direction is smaller than the opening diameter on the ink liquid chamber side.

  In addition, an ink cartridge according to the present invention includes the above-described droplet discharge head.

  In addition, an ink jet recording apparatus according to the present invention includes the above-described droplet discharge head.

  In the nozzle plate manufacturing method according to the present invention, in the nozzle plate in which a plurality of nozzle holes communicating with the ink liquid chamber are arranged, the cross-sectional shape of the nozzle holes on the ink liquid chamber side is in the nozzle hole arrangement direction. In addition, the cross-sectional shape on the ejection side of the nozzle holes is one pulse of laser light so that the opening diameter along the nozzle hole arrangement direction is smaller than the opening diameter on the ink liquid chamber side. The nozzle plate is moved by a predetermined distance in parallel with the arrangement direction of the nozzle holes for each irradiation, and the nozzle holes are formed by repeating the irradiation and the movement of the nozzle plate in the same direction again.

  According to the present invention, it is possible to obtain a nozzle shape having excellent bubble discharging properties.

It is a block diagram of the droplet discharge head which concerns on embodiment of this invention. It is sectional drawing of the droplet discharge head which concerns on embodiment of this invention. It is a top view of the base material which joined the nozzle plate and liquid chamber board | substrate which concern on embodiment of this invention. It is explanatory drawing of the nozzle hole which concerns on embodiment of this invention. It is a comparison figure of the nozzle plate which concerns on embodiment of this invention, and the conventional nozzle plate. It is a schematic diagram of a laser apparatus. It is a schematic diagram of a laser apparatus. It is explanatory drawing of the formation method of the nozzle hole which concerns on embodiment of this invention. It is explanatory drawing of the formation method of the nozzle hole which concerns on embodiment of this invention. It is explanatory drawing of the formation method of the nozzle hole which concerns on other embodiment of this invention. It is a figure which shows a nozzle shape. 1 is a schematic diagram of an image forming apparatus. 2 is an explanatory plan view of a main part of the image forming apparatus. FIG.

  Next, the best mode for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of a droplet discharge head according to an embodiment of the present invention. 2 shows a cross section in the direction of FIG. 1a-a (FIG. 2 (a)) and a cross section in the direction of FIG. 1b-b (FIG. 2 (b)).

  This droplet discharge head is configured by laminating a nozzle plate 100, a liquid chamber substrate 102, a vibration substrate 105, and an actuator substrate 108.

  Here, the nozzle plate 100 is formed of a sheet material 110 made of polyimide resin having a water-repellent layer 109 on the droplet discharge surface side, and the nozzle holes 101 are arranged.

  In the liquid chamber substrate 102, a communication hole 103 communicating with the nozzle hole 101 and an ink liquid chamber 104 are formed. Here, the liquid chamber substrate 102 is formed of a silicon wafer.

  A diaphragm-like diaphragm 106 corresponding to the ink liquid chamber 104 and forming one surface of the ink liquid chamber 104 is formed on the vibration substrate 105. Here, a Ni base material is used as the vibration substrate 105.

  Piezoelectric elements 107 corresponding to the ink liquid chambers 104 are arranged on the actuator substrate 108.

  In the droplet discharge head configured as described above, the piezoelectric element 107 formed on the actuator substrate 108 contracts by an electromechanical conversion action by a drive signal supplied from an external electric circuit (not shown), and the piezoelectric element The diaphragm 106 corresponding to 107 is displaced. Pressure is applied to the ink liquid stored in the ink liquid chamber 104 formed on the liquid chamber substrate 102 due to the displacement of the vibration plate 106, and the ink droplets are ejected from the nozzle hole 101 through the communication hole 103 communicating with the ink liquid chamber 104. Is discharged.

  Next, the form of the nozzle plate and the nozzle hole in the embodiment of the present invention will be described.

  FIG. 3 shows a plan view of a base material obtained by joining the nozzle plate and the liquid chamber substrate. 4A shows an enlarged view of the vicinity of the nozzle hole, and FIG. 4B shows a cross-sectional view thereof. As shown in the figure, the nozzle hole 101 has a shape in which the incident port 113 on the ink liquid chamber 104 side has an oval or elliptical shape along the nozzle arrangement direction, and the discharge port 112 has a substantially circular shape. It has become.

  Further, in the direction perpendicular to the arrangement direction of the nozzle holes 101, that is, in the direction of the minor axis of the ellipse, the diameters of the incident port 113 and the ejection port 112 are formed to be the same diameter.

  Further, as shown in FIG. 4C, the inner wall of the nozzle is formed in an expanding shape that gradually increases in diameter from the discharge port 112 along the incident port 113.

  By forming the nozzle holes in this way, the nozzle holes 101 can be arranged at a distance L1 from the end of the ink liquid chamber 104 as shown in FIG. The distance between the nozzle hole 101 and the end of the ink liquid chamber 104 can be shortened with respect to the distance L2 of the conventional configuration shown in the figure, and the bubbles flowing to the end of the liquid chamber can be quickly discharged through the nozzle hole. Can be discharged out of the head.

  Furthermore, since the ink liquid chamber side of the nozzle holes is formed long in the nozzle hole arrangement direction (lateral direction in FIG. 5), there is also an effect of eliminating a dead space generated at the corner of the ink liquid chamber. That is, since the opening on the ink liquid chamber side of the nozzle hole reaches the vicinity of the corner of the ink liquid chamber as compared with the conventional configuration, the flow of ink also occurs in this portion, and bubbles and the like are trapped in the corner. Can solve the problem of

  The dead space at the corners is not limited to the configuration shown in FIG. 5B, but is generated even if the ink liquid chamber side has a larger circular shape than the ejection side as shown in FIG. 5C. End up. The present application has an effect of further reducing the dead space as compared with FIG.

  Here, the liquid chamber substrate 102 is formed of a 400 μm thick silicon substrate having a crystal orientation <110>, a communication hole 103 communicating with the opening of the nozzle hole 101, and an ink liquid chamber 104 for storing ink liquid. Is formed. The nozzle plate 100 is made of a polyimide film having a thickness of 25 μm with a water repellent film provided on the outermost surface, and is bonded to the liquid chamber substrate 102 with an adhesive (not shown).

  Next, an outline of laser processing equipment used for forming nozzle holes in the embodiment of the present invention will be described.

  FIG. 6 is a schematic diagram of the laser apparatus according to this embodiment. As shown in the drawing, a laser beam 400 oscillated from a laser oscillator 401 is applied to a processing workpiece 403 (in this case, a liquid chamber substrate and a nozzle plate bonded together) held on a processing stage 404 with a mask 402. It is the structure which permeate | transmits and irradiates the process workpiece 403.

  Here, as a laser light source, it is preferable to use a laser light 400 having a wavelength of 266 μm by a wavelength conversion system based on a YAG laser.

  As a laser light source, a YAG laser, an excimer laser, or the like is generally used. However, with such a laser, since the oscillation frequency is about several hundred Hz, continuous processing at high speed is difficult. For this reason, the movement of the nozzle plate is usually stopped during laser irradiation, and when irradiation is completed, the nozzle plate moves to the next irradiation position at a high speed, and the next irradiation is performed after the stop. In such processing, the positional accuracy between the nozzles deteriorates due to backlash of the apparatus due to repeated movement and stoppage.

  Of course, it is possible to move the YAG laser and excimer laser at a constant speed so that the backlash does not occur as described above. However, since the moving speed is determined by the oscillation frequency, the nozzle holes between which the laser oscillation is not necessary are determined. Movement is also impractical because it has to move at the same speed and significantly reduces productivity.

  However, if a laser beam having a wavelength of 266 μm (harmonic) obtained by wavelength conversion of the YAG laser described above is used, the oscillation frequency can be increased several hundred times from 20 to 50 kHz by wavelength conversion. It becomes possible to process a row of holes without stopping the apparatus.

  Further, such processing is possible only in the configuration of the present application having a major axis in the nozzle hole arrangement direction, and in the conventional configuration having a major axis in a direction perpendicular to the nozzle hole arrangement direction, the wavelength conversion of the YAG laser can be used. Such high speed machining cannot be performed.

  Further, as shown in FIG. 7, a general laser beam 400 has a beam diameter of about 2 mm, and is transmitted through a mask 402 corresponding to the diameter of the nozzle hole 101 to be formed and irradiated onto the nozzle plate 100 to obtain a desired laser beam. The opening diameter is obtained.

  Next, a method for forming nozzle holes in the embodiment of the present invention will be schematically described. FIG. 8A shows a plan view when the nozzle holes are formed, and FIG. 8B shows a cross-sectional view thereof. Here, an example in which the nozzle hole 101 is schematically formed by laser irradiation of 5 pulses is shown.

  As shown in the figure, the nozzle hole 101 is composed of “nozzle machining 1-1” to “nozzle machining 1-5” steps for each pulse. First, one pulse of laser light is produced in the “nozzle machining 1-1” step. 400 is irradiated to the nozzle plate 100, and then the laser beam 400 of the second pulse is irradiated as a step of “nozzle processing 1-2” with the movement of the nozzle plate 100.

  Thus, by simultaneously irradiating the laser beam 400 and operating the nozzle plate 100, a nozzle hole having a major axis or an ellipse shape with respect to the moving direction of the workpiece is formed. That is, the nozzle plate 100 is a method of forming the nozzle hole 101 that is synchronized with the oscillation frequency of the laser beam 400 while being moved at a constant speed during the formation of the nozzle hole 101.

  Here, 5 pulses are used as an explanation. However, as actual formation conditions, the nozzle hole 101 is formed with 50 pulses with an oscillation frequency of 20 KHz. Here, the output of the laser beam 400 is 1.5 W. Further, during the formation of the nozzle hole 101, the movement of the nozzle plate is along the arrangement direction of the nozzle holes. Are formed in the same diameter.

  By repeating the formation steps as described above, that is, the movement time to the adjacent nozzle hole 101 is stopped by stopping the oscillation of the laser beam 400, the nozzle hole 101 is formed while moving the workpiece 403.

  Next, the processed substrate in the embodiment of the present invention will be described. As shown in FIG. 9, a base material in which a nozzle plate 100 and a liquid chamber substrate 102 are joined is used as a silicon base material 802 as a processing base material.

  As shown in the figure, a plurality of head chips corresponding to the nozzle plate 100 and the liquid chamber substrate 102 of the ink jet head are formed in the silicon substrate 802, and the silicon substrate 802 is used as a processing base material when the nozzle hole 101 is formed. The form that handles.

  The silicon substrate 802 held on the processing stage of the laser device forms the nozzle hole 101 by repeating the processing steps described above while moving at a constant speed along a moving path 801 as shown in the figure, for example. . Further, the productivity can be further increased by making the moving speed between the head chips 803 higher than the moving speed at the time of processing.

  Next, a second embodiment will be described in detail with reference to FIG. In the first embodiment, since the opening pattern of the mask 402 is a perfect circle, the cross-sectional shape of the laser beam 400 is also a substantially circular shape, and the shape of the discharge port 112 of the nozzle hole 101 formed is the nozzle hole. It is formed in an elongated shape having a minor axis with respect to the arrangement direction.

  In contrast, in the second embodiment, the opening pattern of the mask 402 is made to be an ellipse so that the cross-sectional shape of the laser beam 400 is an ellipse, and the discharge port 112 of the nozzle hole 101 formed is substantially true. It is formed in a circular shape.

  As described above, according to the embodiment of the present invention, since the shape of the laser beam 400 can be arbitrarily formed by using a mask, a desired nozzle shape having a horizontally long shape with respect to the arrangement direction of the nozzle holes is formed. Is possible.

  Further, regarding the taper shape of the nozzle hole, the nozzle shape is preferably tapered as shown in FIG. By supplying a taper, ink can be supplied more smoothly. The taper angle θ is preferably 1 to 45 degrees, and more preferably 3 to 30 degrees. If θ is less than 1 degree, ink refill is not sufficient. Conversely, if it exceeds 45 degrees, high integration of nozzles will be hindered.

  Next, an example of an image forming apparatus provided with a droplet discharge head or a droplet discharge device according to the present invention will be described with reference to FIGS. 12 is an explanatory side view for explaining the overall configuration of the apparatus, and FIG. 13 is an explanatory plan view of a main part of the apparatus.

  In this image forming apparatus, a carriage 1103 is slidably held in a main scanning direction by a guide rod 1101 and a guide rail 1102 that are horizontally mounted on left and right side plates (not shown), and a timing belt 1105 is slid by a main scanning motor 1104. Is moved and scanned in the direction indicated by the arrow (main scanning direction).

  The carriage 1103 includes, for example, a plurality of recording heads 1107 including four droplet ejection heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink discharge ports are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet discharge direction facing downward. In addition, as a droplet discharge head constituting the recording head 1107, a head using a piezoelectric actuator such as a piezoelectric element is used.

  In addition, the carriage 1103 is equipped with a sub tank 1108 for each color for supplying ink of each color to the recording head 1107. Ink is supplied to the sub tank 1108 from a main tank (ink cartridge) through an ink supply tube (not shown).

  In this embodiment, the sub-tank 1108 and the recording head 1107 constitute the droplet discharge device according to this embodiment. However, the recording head 1107 is constituted by the droplet discharge head according to this embodiment, and a sub-tank 1108 is provided separately. It is also possible to adopt a configuration, or a configuration in which an ink cartridge is mounted without using a sub tank.

  On the other hand, as a paper feeding unit for feeding paper 1112 stacked on a paper stacking unit (pressure plate) 1111 such as a paper feeding cassette 1110, a half-moon roller (separately feeding paper 1112 from the paper stacking unit 1111 one by one ( A separation pad 1114 made of a material having a large friction coefficient is provided opposite to the sheet feeding roller 1113 and the sheet feeding roller 1113, and the separation pad 1114 is urged toward the sheet feeding roller 1113 side.

  As a transport unit for transporting the paper 1112 fed from the paper feed unit below the recording head 1107, a transport belt 1121 for electrostatically attracting and transporting the paper 1112, and a paper feed unit A counter roller 1122 for transporting the paper 1112 sent via the guide 1115 sandwiched between the transport belt 1121 and the paper 1112 sent substantially vertically upward is turned approximately 90 ° and copied onto the transport belt 1121. A conveyance guide 1123 for adjusting the pressure and a pressure roller 1125 at the front end that is urged toward the conveyance belt 1121 by a pressing member 1124. Further, a charging roller 1126 which is a charging unit for charging the surface of the conveyance belt 1121 is provided.

  Here, the conveyance belt 1121 is an endless belt, is stretched between the conveyance roller 1127 and the tension roller 1128, and the conveyance roller 1127 rotates from the sub-scanning motor 1131 via the timing belt 1132 and the timing roller 1133. By doing so, it is configured to circulate in the belt conveyance direction (sub-scanning direction) of FIG. A guide member 1129 is disposed on the back side of the conveyance belt 1121 corresponding to the image forming area formed by the recording head 1107.

  Also, as shown in FIG. 12, a slit disk 1134 is attached to the shaft of the transport roller 1127, and a sensor 1135 for detecting the slit of the slit disk 1134 is provided, and these slit disk 1134 and sensor 1135 An encoder 1136 is configured.

  The charging roller 1126 is disposed so as to contact the surface layer of the conveyor belt 1121 and rotate following the rotation of the conveyor belt 1121, and applies 2.5N to both ends of the shaft as a pressing force.

  Further, as shown in FIG. 12, an encoder scale 1142 having slits is provided on the front side of the carriage 1103, and an encoder sensor comprising a transmissive photosensor that detects the slits of the encoder scale 1142 on the front side of the carriage 1103. 1143 is provided, and these constitute an encoder 1144 for detecting the position of the carriage 1103 in the main scanning direction (position relative to the home position).

  Further, as a paper discharge unit for discharging the paper 1112 recorded by the recording head 1107, a separation unit for separating the paper 1112 from the conveying belt 1121, a paper discharge roller 1152, a paper discharge roller 1153, and paper discharge A paper discharge tray 1154 for stocking the paper 1112 to be stored.

  A double-sided paper feeding unit 1161 is detachably attached to the back. The double-sided paper feeding unit 1161 takes in the paper 1112 returned by the reverse rotation of the transport belt 1121, reverses it, and feeds it again between the counter roller 1122 and the transport belt 1121.

  In the image forming apparatus configured as described above, the paper 1112 is separated and fed one by one from the paper feeding unit, and the paper 1112 fed substantially vertically upward is guided by the guide 1115, and the conveyance belt 1121 and the counter roller 1122. The leading end is guided by the conveying guide 1123 and pressed against the conveying belt 1121 by the leading end pressing roller 1125, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately repeated from the high voltage power source to the charging roller 1126 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 1121 is alternating, that is, In the sub-scanning direction, which is the circumferential direction, plus and minus are alternately charged in a band shape with a predetermined width. When the paper 1112 is fed onto the positively and negatively charged transport belt 1121, the paper 1112 is attracted to the transport belt 1121 by electrostatic force, and the paper 1112 is transported in the sub-scanning direction by the circular movement of the transport belt 1121. Is done.

  Therefore, by driving the recording head 1107 according to the image signal while moving the carriage 1103, ink droplets are ejected onto the stopped paper 1112 to record one line, and after the paper 1112 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 1112 has reached the recording area, the recording operation is finished, and the paper 1112 is discharged onto the paper discharge tray 1154.

  In the case of duplex printing, when recording on the front surface (surface to be printed first) is completed, the recording belt 1112 is fed into the duplex paper feeding unit 1161 by rotating the conveyor belt 1121 in a reverse direction. The paper 1112 is reversed (with the back surface being the printing surface), and is fed again between the counter roller 1122 and the conveyor belt 1121, and the timing is controlled, and the sheet 1112 is conveyed onto the conveyor bell 1121 as described above. Then, after recording on the back surface, the paper is discharged onto a paper discharge tray 1154.

  Note that the image forming apparatus according to the embodiment of the present invention can also be applied to a printer, a facsimile machine, a copying machine, a complex machine of these, and the like. Further, the present invention can also be applied to a droplet discharge head or a droplet discharge device that discharges a liquid other than ink, such as a DNA sample, a resist, or a pattern material, or an image forming apparatus that includes these.

  Hereinafter, the operation and effect of the droplet discharge head according to the embodiment of the present invention will be described.

  According to the embodiment of the present invention, it is possible to achieve high production while ensuring precise machining accuracy for forming an elliptical or elliptical nozzle hole, and for forming different diameter nozzles having an incident diameter and a discharge diameter. In this embodiment, the liquid droplet ejection head of the present embodiment is designed to improve the bubble discharge property by optimizing the nozzle shape or to stabilize the ejection characteristics. The shape and manufacturing method have been shown to be effective. In addition, in response to the problem of forming an elliptical or elliptical nozzle hole with an excimer laser, the nozzle hole is formed by synchronizing the laser oscillation frequency and the movement of the workpiece by using wavelength-converted YAG laser light. It was shown that the processing time can be shortened and productivity can be improved.

  According to the droplet discharge head in the present embodiment, since the distance between the nozzle hole and the ink liquid chamber can be kept to a minimum, the bubble discharge performance is improved and the ink can be discharged with respect to the opening diameter on the discharge side. Since the opening diameter on the liquid chamber side is an ellipse or an ellipse, it is possible to realize a nozzle hole and a nozzle plate effective for ink droplet ejection stability.

  Further, by using a polyimide resin film as the nozzle plate, it is possible to form high-quality and high-precision nozzle holes and nozzle plates by ablation processing.

  In addition, according to the method of manufacturing a droplet discharge head in the present embodiment, by using a wavelength-converted YAG laser as a processing laser light source, it becomes possible to perform ablation processing, and an optical required for an excimer laser or the like. The nozzle hole can be formed by a simple laser device that does not require an element.

  In addition, by forming the nozzle holes while moving the nozzle plate, which is a workpiece, it is possible to reduce the processing time and form a nozzle hole with excellent productivity.

  In addition, since the nozzle hole is formed while moving the nozzle plate at a constant speed, there is no need for high accuracy of the processing stage such as static accuracy, so that the laser device can be simplified and the equipment cost can be reduced. .

  In addition, since a desired opening shape can be obtained by forming the nozzle hole with the laser light transmitted through the mask pattern, it is possible to form an optimum nozzle hole shape with stable ejection characteristics.

  In addition, in the ink cartridge using the droplet discharge head or the ink jet recording apparatus according to the present embodiment, higher-definition image recording is possible due to the improvement of the ink droplet discharge efficiency and the landing position accuracy. In addition, since the nozzle holes can be arranged at a narrow pitch, it is possible to record an image with higher image quality.

  Although the embodiments have been described above, various modifications and changes can be made to these embodiments and specific examples without departing from the broad scope and scope of the present invention defined in the claims.

  The present invention can be applied to a liquid discharge head that discharges liquid as fine droplets, which is preferably used in an inhaler used when a liquid medicine is inhaled as a mist in the medical field.

DESCRIPTION OF SYMBOLS 100 Nozzle plate 101 Nozzle hole 102 Liquid chamber board | substrate 103 Communication hole 104 Ink liquid chamber 105 Vibration board 106 Vibration board 107 Piezoelectric element 108 Actuator board

Japanese Patent No. 3127570 Japanese Patent No. 3285041 JP 2003-145774 A

Claims (9)

A liquid chamber substrate having an ink liquid chamber;
A nozzle plate in which a plurality of nozzle holes communicating with the ink liquid chamber are arranged;
In a droplet discharge head comprising: a discharge unit that applies pressure to the ink liquid chamber and discharges the ink liquid in the ink liquid chamber as a droplet from the nozzle hole;
The cross-sectional shape of the nozzle hole on the liquid chamber substrate side has an oval or elliptical shape with respect to the arrangement direction of the nozzle hole, and the cross-sectional shape on the discharge side of the nozzle hole is in the arrangement direction of the nozzle hole. A droplet discharge head characterized in that the opening diameter along the opening is smaller than the opening diameter on the ink liquid chamber side.   2. The droplet discharge head according to claim 1, wherein the opening diameters of the ink liquid chamber side and the discharge side in the direction orthogonal to the arrangement direction of the nozzle holes are the same.   The droplet discharge head according to claim 1, wherein the nozzle substrate is formed of a polyimide film.   An ink cartridge comprising the droplet discharge head according to any one of claims 1 to 3.   An ink jet recording apparatus comprising the droplet discharge head according to claim 1. In the nozzle plate in which a plurality of nozzle holes communicating with the ink liquid chamber are arranged,
The cross-sectional shape of the nozzle holes on the ink liquid chamber side has an oval or elliptical shape with respect to the arrangement direction of the nozzle holes, and the cross-sectional shape on the discharge side of the nozzle holes is in the arrangement direction of the nozzle holes. The nozzle plate is moved by a predetermined distance in parallel to the arrangement direction of the nozzle holes for each pulse irradiation so that the opening diameter along the opening is smaller than the opening diameter on the ink liquid chamber side. The nozzle plate is formed by repeatedly moving the nozzle plate in the same direction to form the nozzle hole.   7. The method of manufacturing a nozzle plate according to claim 6, wherein the nozzle holes are formed using a wavelength-converted YAG laser.   When forming the nozzle holes, the nozzle plate is moved at the same speed as during the movement even during the irradiation of the laser beam, thereby moving at least one row of nozzle holes arranged in the nozzle plate at a constant speed. The nozzle plate manufacturing method according to claim 6 or 7, wherein the nozzle plate is formed. The laser beam is applied to the nozzle plate after passing through a mask,
9. The method of manufacturing a nozzle plate according to claim 6, wherein the cross-sectional shape of the laser beam is formed by an opening pattern of a mask.

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