JP2018122536A - Fluid discharge head and fluid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid discharge head which improves position accuracy of drawing and can remove foreign substances such as dust and fuzz adhering to nozzles, and a fluid discharge device.SOLUTION: A fluid discharge head 50 comprises: nozzles 54 discharging fluid; a first driving section 55 pressurizing the fluid and causing the fluid to be discharged via the nozzles 54; throttle members 56 being positioned inside the nozzles 54 and formed into tapered shapes in a discharge direction of the fluid; and a second driving section 57 subjecting the throttle members 56 to forward/reverse movement in the discharge direction. By subjecting the throttle members 56 to the forward/reverse movement with respect to the nozzles 54, a passing sectional area S1 when variably widening/narrowing the passing sectional area S1 of the fluid is smaller than an opening cross sectional area S2 at a portion P2 becoming the discharge direction than a portion P1 in the nozzles 54 where the passing sectional area S1 is set.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fluid discharge head and a fluid discharge apparatus including the fluid discharge head.

  2. Description of the Related Art Conventionally, fluid ejecting apparatuses such as ink jet printers that eject fluid such as ink from nozzles of a fluid ejecting head are known. The fluid ejection head drives a piezoelectric element as an actuator to pressurize ink in the head and eject it from the nozzle, and the ejected ink droplets land on a print medium such as paper to perform drawing. At this time, by controlling the amount of displacement of the piezoelectric element to be, for example, three levels (large, medium, and small), the ink weight to be ejected is changed to be three types (large, medium, and small). There is also a fluid ejecting apparatus that improves drawing efficiency.

  Further, in the fluid ejection device, the ejected liquid may adhere to the nozzle of the fluid ejection head, or foreign matter such as dust or debris may adhere to the nozzle. When the liquid or dust particles adhere to the nozzle, the liquid is not properly discharged from the nozzle, which may cause deterioration in image quality.

  In Patent Document 1, in an ink jet printing apparatus that draws ink on an recording material by ejecting ink from an orifice according to an image signal, at least a part of the orifice forming member is a composite in which a hard material and a piezoelectric element are integrated. It is disclosed to form from a member.

Japanese Patent Laid-Open No. 7-81057

  By controlling the amount of displacement of the piezoelectric element to be three steps (large, medium, and small) as described above, the ink weight to be ejected is changed to be three types (large, medium, and small). In particular, when the amount of displacement is “small”, the discharge pressure (discharge speed) is low, and the ink weight is also “small”, so it is easy to land off the intended position, and the drawing position There was a problem that the accuracy decreased.

When trying to apply the ink jet printing apparatus of Patent Document 1 to a fluid ejecting apparatus such as an ink jet printer, there has been a conventional problem that foreign matters such as dust debris adhere to flat hard material portions and orifices.
Therefore, there has been a demand for a fluid ejection head and a fluid ejection device that can improve the positional accuracy of drawing and remove foreign matters such as dust marks adhering to the nozzle.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A fluid discharge head according to this application example includes a nozzle that discharges a fluid, a first driving unit that pressurizes the fluid and discharges the fluid through the nozzle, and is located inside the nozzle. And a second drive unit that moves the throttle member forward and backward in the discharge direction, and allows the fluid to pass by moving the throttle member forward and backward relative to the nozzle. When the cross-sectional area is variable, the passage cross-sectional area is smaller than the opening cross-sectional area at the part in the discharge direction from the part in the nozzle where the passage cross-sectional area is set.

  According to the fluid discharge head of this application example, the first driving unit pressurizes the fluid and discharges the fluid through the nozzle. In addition, the second drive unit moves the throttle member forward and backward relative to the nozzle, and the passage cross-sectional area when the passage cross-sectional area of the fluid is variable is changed from the portion of the nozzle where the passage cross-sectional area is set to the discharge direction. It is made small with respect to the opening cross-sectional area at the site. Thereby, it becomes possible to vary the discharge speed of the fluid discharged from the nozzle. Therefore, the fluid ejection head can improve the drawing position accuracy and remove foreign matters such as dust marks adhering to the nozzle.

  Application Example 2 In the fluid ejection head according to the application example described above, it is preferable that the nozzle is formed in a tapered shape in the ejection direction.

  According to the fluid ejection head of this application example, by changing the ejection speed of the fluid ejected from the nozzle, the drawing position accuracy can be improved, and foreign matter such as dust particles adhering to the nozzle can be removed. It becomes possible.

  Application Example 3 In the fluid ejection head according to the application example described above, it is preferable that the nozzle is formed in a tapered shape in the ejection direction.

  According to the fluid ejection head of this application example, it is possible to improve the drawing position accuracy by changing the ejection speed of the fluid ejected from the nozzle. Further, it is possible to remove foreign matters such as dust marks entering the head from the nozzle.

  Application Example 4 In the fluid ejection head according to the application example described above, it is preferable that the first driving unit and the second driving unit are driven independently.

  According to the fluid discharge head of this application example, by driving the first drive unit and the second drive unit independently, for example, only the second drive unit is driven and the throttle member is moved in the discharge direction. By moving forward and backward, the fluid in the nozzle and cavity can be vibrated. By this vibration, foreign matters such as dust marks adhering to the nozzle can be easily separated from the nozzle, so that the foreign matter can be removed.

  Application Example 5 It is preferable that the fluid ejection head according to the application example drives the second drive unit in correspondence with the drive of the first drive unit.

According to the fluid discharge head of this application example, the second drive unit is driven in correspondence with the drive of the first drive unit. Thus, in order to improve the drawing efficiency, the first drive unit and the first drive unit are different from the conventional adjustment of the ink weight to be ejected by changing the amount of pressure applied by the first drive unit. It is possible to adjust the ejection speed and fluid weight of the fluid to be ejected in combination with the two driving units.
For example, while the pressurization amount of the first drive unit is kept constant and the second drive unit is driven, the passage cross-sectional area is set by varying the passage cross-sectional area of the fluid in the nozzles. The opening cross-sectional area at the portion in the discharge direction is smaller than the portion at the nozzle to be discharged. Thereby, the discharge speed of the fluid to be discharged can be increased and discharged. As a result, for example, even when the fluid weight to be ejected is “small”, the ejection speed can be increased and ejected, so that the ejected droplets are less susceptible to external factors such as wind. Accordingly, it is possible to prevent landing from being shifted from the intended position with respect to the print medium, and it is possible to improve the drawing position accuracy. In addition, even when the fluid weight is “small”, it is possible to remove foreign matter such as dust particles entering the nozzle and dust particles adhering to the nozzle by increasing the discharge speed and discharging. It becomes possible.

  Application Example 6 In the fluid ejection head according to the application example described above, the throttle member is preferably formed in a tapered shape that reduces the outer diameter in the fluid ejection direction.

  According to the fluid discharge head of this application example, the throttle member can be easily configured by forming the throttle member in a tapered shape whose outer diameter is reduced. In addition, it becomes easy to control the passage cross-sectional area of the fluid due to the movement of the throttle member, thereby making it easier to control the discharge weight of the fluid.

  Application Example 7 In the fluid ejection head according to the application example, it is preferable that the second driving unit includes a piezoelectric element.

  According to the fluid discharge head of this application example, the second drive unit is configured to include the piezoelectric element, whereby the second drive unit can be reduced in size.

  Application Example 8 A fluid ejection device according to this application example includes any one of the fluid ejection heads described above and a control unit that controls operations of the first drive unit and the second drive unit. And

  According to the fluid ejection device of this application example, since the fluid ejection head that improves the positional accuracy of the drawing and can remove foreign matters such as dust marks attached to the nozzles is provided, it is possible to maintain and improve the drawing quality. it can.

1 is a schematic diagram illustrating a configuration of a printer according to a first embodiment. FIG. 2 is a schematic cross-sectional view illustrating a configuration of an ejection head. Sectional drawing which shows the state in which an aperture member is located in the initial position at the time of drawing. Sectional drawing which shows the state in which an aperture member is located in an intermediate position at the time of drawing. Sectional drawing which shows the state in which an aperture member is located in the last position at the time of drawing. The schematic diagram which shows the passage cross-sectional area of an ink, and the opening cross-sectional area of a nozzle. Sectional drawing which shows the state which removes the foreign material adhering to a nozzle in the discharge head which concerns on 2nd Embodiment. Sectional drawing which shows the state in which an aperture member is located in the initial position at the time of the drawing which concerns on 3rd Embodiment. Sectional drawing which shows the state in which an aperture member is located in an intermediate position at the time of drawing. Sectional drawing which shows the state in which an aperture member is located in the last position at the time of drawing. The schematic diagram which shows the passage cross-sectional area of an ink, and the opening cross-sectional area of a nozzle. Sectional drawing which shows the state which removes the foreign material which accumulates in a communicating path in the discharge head which concerns on 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a scale different from the actual scale for each member in order to make the size recognizable on the drawing.

[First Embodiment]
FIG. 1 is a schematic diagram illustrating a configuration of a printer 1 according to the first embodiment. An outline of the configuration of the printer 1 will be described with reference to FIG.
A printer 1 as a fluid ejection device of the present embodiment is generally configured to include a paper feed mechanism 2, an ink supply mechanism 3, a control unit 4, a head mechanism 5, and the like.

  The paper feed mechanism 2 includes a paper feed motor (PF motor) 21 and a paper feed roller 22 to which a driving force from the paper feed motor 21 is transmitted. In the present embodiment, roll paper P as a print medium is set on the paper feed roller 22. The roll paper P is not limited, and a regular printing paper may be used.

  The ink supply mechanism 3 includes a cartridge holder 31, a pressure pump 32, an ink supply path 33, an ink cartridge 34, and the like. The cartridge holder 31 is attached to a chassis (not shown), for example. An ink cartridge 34 is detachably attached to the cartridge holder 31. Therefore, the printer 1 of the present embodiment has a so-called off-carriage type configuration.

  When supplying ink (corresponding to fluid), the pressurizing pump 32 is operated, and the ink is pushed into the ink supply path 33 by pumping air into the ink cartridge 34 to crush the ink pack. ing.

  The control unit 4 includes a CPU, a memory (ROM, RAM, nonvolatile memory, etc.), an ASIC (Application Specific Integrated Circuit), a bus, a timer, an interface, etc. (all not shown). The control unit 4 receives signals from various sensors, and based on the signals from the sensors, a motor such as a paper feed motor 21, a pressure pump 32, a suction pump (not shown), a head mechanism 5, and the like. Overall control of the drive.

  In addition, data and programs stored in the memory are executed by the CPU, and various functional configurations are realized by the cooperation of the configurations of the control unit 4. In the present embodiment, the memory stores a program and data for performing drive control of a first drive unit 55 (FIG. 2) and a second drive unit 57 (FIG. 2) of the fluid discharge head 50 described later. . Then, the control unit 4 reads the program and data to instruct a driving driver (not shown) to drive the first driving unit 55 and the second driving unit 57, and from the fluid ejection head 50. The ink ejection operation is controlled.

  The control unit 4 is connected to the computer 7 or the like via the transmission / reception unit 41 to perform communication. Accordingly, when the printer 1 receives the print signal PS from the computer 7 side, the printer 1 starts processing for printing based on the received print signal PS.

  The head mechanism 5 of the present embodiment is arranged in a line for each ink color (each liquid type) in a direction perpendicular to the conveyance direction of a print medium such as paper, and has a length equivalent to the width dimension of the print medium. It is configured as a so-called line head. The head mechanism 5 includes a plurality of fluid discharge heads 50 (hereinafter referred to as discharge heads 50) in a direction perpendicular to the transport direction.

  FIG. 2 is a schematic cross-sectional view showing the configuration of the ejection head 50. The configuration of the ejection head 50 will be described with reference to FIG.

  The ejection head 50 includes a reservoir 51, a cavity (pressure chamber) 52, a communication path 53, a nozzle 54, a first drive unit 55, a throttle member 56, a second drive unit 57, and the like.

  The reservoir 51 is connected to the ink supply path 33, communicates in common with each cavity 52, and is installed for each ink color. The reservoir 51 is a portion that stores ink for supplying ink to each cavity 52. In the reservoir 51, an opening 511 communicating with each cavity 52 is formed for each cavity 52.

  The cavity 52 is a portion that is filled with ink from the reservoir 51 through the opening 511 and is applied (pressurized) by driving a first driving unit 55 described later. The communication path 53 is a part that communicates the cavity 52 and the nozzle 54, and constitutes a part of the cavity 52. The nozzle 54 is a portion that ejects ink and includes a discharge port 541. The nozzle 54 includes a tapered portion (hereinafter referred to as a nozzle inner surface 542) formed in a tapered shape (corresponding to a tapered shape) whose inner peripheral diameter decreases toward the discharge port 541. The discharge port 541 is not a taper shape but a straight opening.

  The first drive unit 55 includes a piezoelectric element (piezo element) 551. The piezoelectric element 551 is installed in the upper portion of the cavity 52 and is driven to displace a vibration plate 63 described later, thereby pressurizing ink in the cavity 52 and causing the ink to be ejected from the nozzle 54 (discharge port 541). Discharge.

  The diaphragm member 56 is a member that is connected to a second drive unit 57 described later, and that is transmitted with an enlarged displacement generated by the drive of the second drive unit 57, and moves forward and backward in the discharge direction (the discharge port 541 direction). .

  The throttle member 56 includes a connecting portion 561 that is connected to a displacement magnifying mechanism 572 of the second drive portion 57 to be described later and transmits the displacement, and a throttle portion 562 that faces the nozzle 54 at the tip of the connecting portion 561. ing. The narrowed portion 562 includes a tapered portion (hereinafter referred to as a narrowed portion outer surface 563) formed in a tapered shape (corresponding to a tapered shape) whose outer diameter decreases in the ejection direction.

  The second drive unit 57 includes a piezoelectric element (piezo element) 571 and a displacement enlarging mechanism 572 that enlarges the displacement of the piezoelectric element 571. Note that one end of the piezoelectric element 571 is fixed to a support substrate 65 described later. In addition, one end of the displacement enlarging mechanism 572 is also fixed to the support substrate 65.

  The displacement enlarging mechanism 572 is configured by applying the lever principle. The displacement magnifying mechanism 572 is connected to the other end of the piezoelectric element 571 to constitute a force point (not shown), and also constitutes a fulcrum and an action point (both not shown). Then, the displacement magnifying mechanism 572 operates based on the lever principle to magnify the minute displacement accompanying the operation displacement of the piezoelectric element 571 with the fulcrum as a reference at the point of action. The displacement magnification rate in the displacement magnification mechanism 572 is set by the ratio of the distance between the action point and the fulcrum with respect to the distance between the force point and the fulcrum. It is to be noted that the connecting portion 561 of the diaphragm member 56 is connected to the action point.

  With the configuration of the second drive unit 57 described above, the displacement enlarging mechanism 572 expands the displacement corresponding to the displacement of the piezoelectric element 571 and transmits it to the aperture member 56. Therefore, the diaphragm member 56 can move forward and backward in the discharge direction.

Here, an outline of the manufacturing process of the ejection head 50 will be described.
First, the intermediate layer 64 is laminated on the vibration plate 63, and the piezoelectric element 551 is installed on the vibration plate 63 via the intermediate layer 64. Next, the cavity substrate 62 is laminated on the vibration plate 63. The cavity substrate 62 is made of, for example, a single crystal of Si (silicon), and the reservoir 51, the cavity 52, and the communication path 53 are formed by etching the cavity substrate 62. Here, each cavity 52 is formed in the same volume, respectively. Similarly, each communication path 53 is also formed in the same volume. The diaphragm 63 is made of an amorphous material such as SiO ₂ (silicon dioxide), and has resistance to erosion caused by etching.

  The intermediate layer 64 disposed between the vibration plate 63 and the piezoelectric element 551 is formed of, for example, a metal oxide having a NaCl (sodium chloride) structure. Due to the intermediate layer 64, the piezoelectric element 551 and the vibration plate 63 are preferably prevented from being peeled off, and the vibration of the piezoelectric element 551 can be more reliably transmitted to the vibration plate 63.

  Next, the nozzle substrate 61 in which the nozzles 54 are formed is attached to the cavity substrate 62 in which the reservoir 51, the cavity 52, and the communication path 53 are formed. The nozzle substrate 61 is attached to the cavity substrate 62 such that each discharge port 541 corresponds to each cavity 52 (communication path 53), and each discharge port 541 is provided in each cavity 52 (communication path 53). Communicate.

  Finally, the support substrate 65 on which the second drive unit 57 (which connects the diaphragm member 56) is installed is attached to the intermediate layer 64 side. At that time, the throttle member 56 is inserted into a hole 66 formed in the intermediate layer 64 and the diaphragm 63 and is installed so as to protrude into the communication path 53. The hole 66 is configured so that the throttle member 56 (connecting portion 561) can slide, and ink leakage from the communication path 53 can be prevented. The ejection head 50 is completed through the above steps.

  3A, 3B, and 3C are cross-sectional views illustrating positions where the diaphragm member 56 that moves forward and backward is moved when the ejection head 50 is drawn. Specifically, FIG. 3A is a cross-sectional view showing a state in which the aperture member 56 is located at the initial position during drawing, and FIG. 3B is a cross-sectional view showing a state in which the aperture member 56 is located at the intermediate position during drawing, FIG. 3C is a cross-sectional view showing a state in which the aperture member 56 is located at the final position during drawing. FIG. 4 is a schematic diagram showing the ink cross-sectional area S1 and the opening cross-sectional area S2 of the nozzle 54 (discharge port 541). 3A, FIG. 3B, FIG. 3C, and FIG. 4 are enlarged views of the configuration around the nozzle 54 for convenience of explanation.

  Hereinafter, with reference to FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 4, the ejection head 50 when the ejection head 50 of the present embodiment performs drawing by ejecting ink toward the print medium (roll paper P). The operation of will be described.

  The conventional ejection head does not include the second drive unit 57 and the diaphragm member 56 of the present embodiment. When drawing, for example, the first drive unit 55 (piezoelectric element 551) is driven to eject ink. Was. Further, in order to increase the printing efficiency, for example, by changing the driving voltage in three stages of large, medium, and small, the amount of displacement of the piezoelectric element 551 is changed to large, medium, and small, and ink is ejected. The weight was changed from large to medium to small.

  In the present embodiment, the control unit 4 performs control to drive the second drive unit 57 in accordance with the drive of the first drive unit 55 (piezoelectric element 551) via a drive driver. In addition, the control unit 4 performs control so as to discharge with three types of ink weights (large, medium, and small) as in the conventional case.

  In this case, in the present embodiment, the control unit 4 drives the drive voltage of the first drive unit 55 (piezoelectric element 551) with, for example, a voltage corresponding to “large” as in the conventional case, and the piezoelectric element 551 Corresponding to the driving, the second driving unit 57 is driven, and the position of the diaphragm member 56 is moved to the three positions shown in FIGS. S1 (FIG. 4) is variable. Then, the control unit 4 controls the ink cross-sectional area S1 to be smaller than the opening cross-sectional area S2 at the portion in the ejection direction from the portion in the nozzle 54 where the passage cross-sectional area S1 is set. . Thereby, the control unit 4 changes the discharge speed and discharges with three kinds of ink weights (large, medium, and small).

  Here, as shown in FIG. 4, the ink cross-sectional area S <b> 1 is an approximately donut-shaped cross-sectional area formed by a gap between the throttle outer surface 563 and the nozzle inner surface 542 when the ink passes through the nozzle 54. Say. Specifically, it refers to a cross-sectional area formed along the circumferential direction of the throttle portion outer surface 563 (nozzle inner surface 542) with the shortest distance between the throttle portion outer surface 563 and the nozzle inner surface 542 as a cross-sectional width.

  In FIG. 4, with respect to the portion that is the shortest distance between the throttle portion outer surface 563 and the nozzle inner surface 542, the portion of the throttle portion outer surface 563 is indicated as a portion P0, and the portion of the nozzle inner surface 542 is indicated as a portion P1. In this embodiment, since the taper angle A2 of the nozzle 54 is smaller than the taper angle A1 of the narrowed portion 562, the portion of the nozzle 54 where the passage cross-sectional area S1 is set intersects the upper surface of the nozzle substrate 61. It becomes site P1 to do.

  Further, in the present embodiment, the part that is in the discharge direction from the part P1 in the nozzle 54 where the passage cross-sectional area S1 is set is the part that intersects the lower surface of the nozzle substrate 61 (part of the discharge port 541), and the part P2 Become. The opening cross-sectional area at the site P2 (discharge port 541) is defined as the opening cross-sectional area S2. In the present embodiment, the portion P2 is set as a portion having a minimum opening cross-sectional area in the nozzle 54. In other words, the site P2 (opening cross-sectional area S2) is a site where the ink ejection speed is determined when the second drive unit 57 and the diaphragm member 56 are not configured.

  As shown in FIG. 3A, when the throttle member 56 is positioned at the initial position, the throttle portion 562 facing the nozzle 54 has a horizontal position at the tip positioned inside the nozzle 54 with respect to the extended surface of the upper surface of the nozzle substrate 61. It is in a state. In this initial position, the cross-sectional area S1 of the ink passing through the nozzle 54 is set to be equal to or smaller than the opening cross-sectional area S2 at the ejection port 541 (part P2). As a result, the discharge speed is determined by the passage cross-sectional area S1 at the initial position. When the piezoelectric element 551 is driven in this state, ink is ejected from the ejection port 541 with a high ejection pressure and an ink weight of “large” by the pressure applied by the piezoelectric element 551.

  As shown in FIG. 3B, when the throttle member 56 is located at the intermediate position, the throttle portion 562 facing the nozzle 54 is located further inside the nozzle 54 than the initial position, and the nozzle inner surface 542 and the throttle portion outer surface 563 are arranged. The shortest distance is narrower than the shortest distance at the initial position, and the ink passage cross-sectional area S1 is narrower than the passage cross-sectional area S1 at the initial position. In that case, the difference between the opening cross-sectional area S2 at the discharge port 541 and the passage cross-sectional area S1 at the intermediate position is larger than the difference between the passage cross-sectional area S1 at the initial position. Accordingly, the discharge speed at the intermediate position is determined by the portion of the passage cross-sectional area S1 at the intermediate position.

  As a result, when the piezoelectric element 551 is driven in a state where the diaphragm member 56 is located at the intermediate position, the ink is discharged at a higher discharge speed than the ink discharge speed at the initial position by the pressure applied by the piezoelectric element 551. Discharged. At this time, the flow path resistance is increased in the nozzle 54 portion, and the flow rate corresponding to the increased resistance is returned from the cavity 52 to the reservoir 51 side, whereby the ink weight is discharged as “medium”.

  In this way, by disposing the throttle member 56 at the intermediate position, the passage cross-sectional area S1 is made narrower than the passage cross-sectional area S1 at the initial position, thereby increasing the discharge speed even when the ink weight is “medium”. It can be discharged. As a result, even when the ink weight is “medium”, the ejected ink droplets are less susceptible to the influence of external factors such as wind, and thus land on the roll paper P out of the intended position. Can be prevented, and the drawing position accuracy can be improved. Further, since discharge can be performed at a higher discharge speed, foreign matters such as dust particles entering the nozzle 54 and dust particles adhering to the nozzle 54 can be removed.

  As shown in FIG. 3C, when the throttle member 56 is located at the final position, the throttle part 562 facing the nozzle 54 is located further inside the nozzle 54 than the intermediate position, and the nozzle inner surface 542 and the throttle part outer surface 563 The shortest distance is narrower than the shortest distance at the intermediate position, and the ink cross-sectional area S1 is narrower than the cross-sectional area S1 at the intermediate position. In that case, the difference between the opening cross-sectional area S2 at the discharge port 541 and the passage cross-sectional area S1 at the final position is further larger than the difference between the passage cross-sectional area S1 at the intermediate position. Accordingly, the discharge speed at the final position is determined by the portion of the passage cross-sectional area S1 at the final position.

  Accordingly, when the piezoelectric element 551 is driven in a state where the diaphragm member 56 is located at the final position, the ink is ejected at a higher ejection speed than the ink ejection speed at the intermediate position by the pressure applied by the piezoelectric element 551. Is discharged. At this time, the flow path resistance is further increased in the nozzle 54 portion, and the flow rate corresponding to the increased resistance is returned from the cavity 52 to the reservoir 51 side, so that the ink weight is discharged as “small”.

  In this way, by positioning the throttle member 56 at the final position, the passage cross-sectional area S1 is further narrower than the passage cross-sectional area S1 at the intermediate position, so that the discharge speed can be further increased even if the ink weight is “small”. It is possible to discharge with increased. As a result, even when the ink weight is “small”, the ejected ink droplets are less likely to be affected by external factors such as wind, and thus land on the roll paper P out of the intended position. Can be prevented, and the drawing position accuracy can be improved. Further, since the discharge speed can be further increased, it is possible to remove foreign matters such as dust particles entering the nozzles 54 and dust particles adhering to the nozzles 54.

According to the embodiment described above, the following effects can be obtained.
In the fluid ejection head 50 of this embodiment, the first drive unit 55 (piezoelectric element 551) causes ink to be ejected through a nozzle 54 formed in a tapered shape (tapered shape). Further, the second drive unit 57 moves the diaphragm member 56 forward and backward with respect to the nozzle 54, and the passage cross-sectional area S1 when the passage cross-sectional area S1 of the ink is variable is changed to the nozzle where the passage cross-sectional area S1 is set. The opening cross-sectional area S2 at the portion P2 in the discharge direction is smaller than the portion P1 at 54. As a result, the ejection speed of the ink ejected from the nozzle 54 can be varied. Therefore, the fluid ejection head 50 can improve the drawing position accuracy and remove foreign matters such as dust marks adhering to the nozzle 54.

The fluid ejection head 50 according to the present embodiment drives the second drive unit 57 in correspondence with the drive of the first drive unit 55. Thereby, the ejection speed and fluid weight of the ink to be ejected can be adjusted by combining the first drive unit 55 and the second drive unit 57.
Note that the fluid ejection head 50 according to the present embodiment drives the second drive unit 57 in correspondence with the drive of the first drive unit 55, and sets the position of the throttle member 56 (throttle unit 562) to three positions (initial stage). Position, intermediate position, final position). As a result, the cross-sectional area S1 of the ink can be varied widely and the cross-sectional area S1 can be made smaller than the opening cross-sectional area S2 at the portion P2 in the ejection direction from the portion P1 in the nozzle 54 where the passage cross-sectional area S1 is set. Thus, the discharge speed is changed in three stages, and the discharge amount is changed into three types. As a result, even when the ink weight is “small”, it is possible to discharge at a higher discharge speed, so that the discharged ink droplet (droplet) is less susceptible to external factors such as wind. Thus, it is possible to prevent landing on the roll paper P (print medium) that deviates from the intended position, and the drawing position accuracy can be improved. In addition, even when the ink weight is “small”, by discharging at a higher discharge speed, foreign matter such as dust particles entering the nozzle 54 and dust particles adhering to the nozzle 54 is removed. It becomes possible.

  In the fluid discharge head 50 of the present embodiment, the throttle member 56 includes a throttle portion 562 having a throttle portion outer surface 563 formed in a tapered shape with a reduced outer diameter. Thereby, the aperture member 56 can be configured easily. In addition, since it becomes easier to control the cross-sectional area S1 through which the ink passes due to the movement of the diaphragm member 56, it becomes easier to control the weight of the ejected ink.

  According to the fluid ejection head 50 of the present embodiment, the second drive unit 57 includes the piezoelectric element 571, so that the size of the second drive unit 57 can be reduced.

  According to the fluid ejection device (printer 1) of the present embodiment, the fluid ejection head 50 and the control unit 4 that controls the operations of the first drive unit 55 and the second drive unit 57 are configured. As a result, the drawing position accuracy can be improved, foreign matters such as dust marks adhering to the nozzle 54 can be removed, and the drawing quality can be maintained and improved.

[Second Embodiment]
FIG. 5 is a cross-sectional view showing a state in which foreign matter adhering to the nozzle 54 is removed in the ejection head 50 according to the second embodiment. FIG. 5 shows an enlarged configuration around the nozzle 54 for convenience of explanation. With reference to FIG. 5, one mode of the operation in removing the foreign matter adhering to the nozzle 54 will be described.
In addition, since the structure of the discharge head 50 of this embodiment is the same as that of 1st Embodiment, it attaches | subjects the code | symbol similar to 1st Embodiment.

  In the present embodiment, the control unit 4 drives only the second drive unit 57 without driving the first drive unit 55. In other words, the second drive unit 57 is driven independently of the first drive unit 55. Specifically, the control unit 4 drives the second drive unit 57 via a driving driver, and as shown in FIG. 5, the throttle member 56 (the throttle unit 562) is set to the initial position in the first embodiment. Control to reciprocate continuously between the final positions.

  In FIG. 5, the position of the diaphragm member 56 at the initial position is indicated by a solid line, and the position of the diaphragm member 56 at the final position is indicated by a two-dot chain line.

  The ink refilled in the nozzle 54 and the communication path 53 vibrates by the continuous reciprocating movement of the throttle member 56. Due to this vibration, the dust mark adhering to the nozzle inner surface 542 can be easily separated from the nozzle inner surface 542. Also, dust particles that do not adhere to the nozzle inner surface 542 and the like can flow through the nozzle 54 and the communication passage 53 by vibration. This makes it easier for dust dust to flow out of the discharge port 541.

According to the embodiment described above, the following effects can be obtained.
According to the fluid ejection head 50 of the present embodiment, the first drive unit 55 is not driven, and only the second drive unit 57 is driven. Specifically, only the second drive unit 57 is driven, and the diaphragm member 56 is continuously reciprocated between the initial position and the final position in the first embodiment. Thereby, the ink in the nozzle 54 and the communication path 53 is vibrated. Due to this vibration, foreign matters such as dust debris adhering to the nozzle 54 can be easily separated from the nozzle 54, and dust debris accumulated on the nozzle inner surface 542 and the like can be caused to flow in the nozzle 54 and the communication path 53. . As a result, dust particles can easily flow out of the discharge port 541, and foreign substances can be removed.

[Third Embodiment]
FIGS. 6A, 6B, and 6C are cross-sectional views illustrating the positions of the diaphragm member 56 that moves forward and backward when the ejection head 50A is drawn in the ejection head 50A according to the third embodiment. Specifically, FIG. 6A is a cross-sectional view showing a state in which the diaphragm member 56 is located at the initial position during drawing, and FIG. 6B is a cross-sectional view showing a state in which the diaphragm member 56 is located in the intermediate position during drawing. FIG. 6C is a cross-sectional view showing a state in which the aperture member 56 is positioned at the final position during drawing. FIG. 7 is a schematic diagram showing an ink cross-sectional area S5 and an opening cross-sectional area S6 of the nozzle 54A. 6A, 6B, 6C, and 7 show the configuration around the nozzle 54A in an enlarged manner for convenience of explanation.

  Hereinafter, with reference to FIG. 6A, FIG. 6B, FIG. 6C, and FIG. 7, the ejection head 50A when the ejection head 50A of the present embodiment performs drawing by ejecting ink toward the print medium (roll paper P). The operation of will be described.

  The configuration of the ejection head 50A of the present embodiment is the same as that of the first embodiment except that the shape of the nozzle 54A is different from the shape of the nozzle 54 of the first embodiment when compared with the first embodiment. Therefore, the same reference numerals are given to the same components as those in the first embodiment.

  The nozzle 54A of the present embodiment is formed in a taper shape (corresponding to a tapered shape) in which the inner peripheral diameter is reduced in the ink discharge direction, whereas the nozzle 54 of the first embodiment is formed in the ink discharge direction. It is formed in a reverse taper shape (corresponding to a tapered shape) in which the inner peripheral diameter increases. Hereinafter, the reverse tapered surface is referred to as a nozzle inner surface 542A.

  Similarly to the control unit 4 in the first embodiment, the control unit 4 in the present embodiment corresponds to the driving of the first driving unit 55 (piezoelectric element 551) via a driving driver. Control for driving 57 is performed. In addition, the control unit 4 performs control so as to discharge with three types of ink weights (large, medium, and small) as in the conventional case.

  As in the first embodiment, the control unit 4 drives the drive voltage of the first drive unit 55 (piezoelectric element 551) with a voltage corresponding to “large” and also corresponds to the drive of the piezoelectric element 551. By driving the second drive unit 57 and moving the position of the diaphragm member 56 to the three positions shown in FIGS. 6A, 6B, and 6C, the ink cross-sectional area S5 (FIG. 7) inside the nozzle 54A is obtained. Wide and narrow. Then, the control unit 4 controls the ink cross-sectional area S5 to be smaller than the opening cross-sectional area S6 at the part in the ejection direction from the part in the nozzle 54A where the passage cross-sectional area S5 is set. . Thereby, the control unit 4 changes the discharge speed and discharges with three kinds of ink weights (large, medium, and small).

  Here, as shown in FIG. 7, the ink cross-sectional area S5 is an approximately donut-shaped cross-sectional area formed by a gap between the throttle outer surface 563 and the nozzle inner surface 542A when the ink passes through the nozzle 54A. Say. Specifically, it refers to a cross-sectional area formed along the circumferential direction of the throttle portion outer surface 563 (nozzle inner surface 542A) with the shortest distance between the throttle portion outer surface 563 and the nozzle inner surface 542A as a cross-sectional width.

  In FIG. 7, with respect to the portion that is the shortest distance between the throttle portion outer surface 563 and the nozzle inner surface 542A, the portion of the throttle portion outer surface 563 is indicated as a portion P5, and the portion of the nozzle inner surface 542A is indicated as a portion P6. In the present embodiment, since the taper shape of the nozzle 54A is an inverse taper with respect to the taper shape of the throttle portion 562, the portion of the nozzle 54A where the passage cross-sectional area S5 is set is the same as that of the nozzle substrate 61. It becomes the site | part P6 which cross | intersects an upper surface. In addition, the site | part P6 becomes a site | part in which the discharge speed of an ink is determined when the 2nd drive part 57 and the aperture member 56 are not comprised.

  Further, in the present embodiment, the portion in the discharge direction from the portion P6 in the nozzle 54A where the passage cross-sectional area S5 is set is arbitrary, but may be, for example, a portion P7 that intersects the lower surface of the nozzle substrate 61. In addition, the opening cross-sectional area in the part P7 is defined as an opening cross-sectional area S6. Since the part P7 is in the discharge direction from the part P6, the opening cross-sectional area S6 is larger than the passage cross-sectional area S5.

  As shown in FIG. 6A, when the throttle member 56 is positioned at the initial position, the throttle portion 562 facing the nozzle 54A has a horizontal position at the tip positioned inside the nozzle 54A with respect to the extended surface of the upper surface of the nozzle substrate 61. It is in a state. In this initial position, the cross sectional area S5 of the ink for the nozzle 54A is smaller than the opening cross sectional area S6 at the portion P7. As a result, the discharge speed is determined by the passage cross-sectional area S5 at the initial position. When the piezoelectric element 551 is driven in this state, ink is ejected from the nozzle 54A with a high ejection pressure and an ink weight of “large” by the pressure applied by the piezoelectric element 551.

  As shown in FIG. 6B, when the throttle member 56 is located at the intermediate position, the throttle portion 562 facing the nozzle 54A is located further inside the nozzle 54A than the initial position, and the nozzle inner surface 542A and the throttle portion outer surface 563 are located. The shortest distance becomes narrower than the shortest distance at the initial position, and the ink cross-sectional area S5 becomes narrower than the cross-sectional area S5 at the initial position. In that case, the difference between the opening cross-sectional area S6 at the portion P7 and the passage cross-sectional area S5 at the intermediate position is further larger than the difference between the passage cross-sectional area S5 at the initial position. Accordingly, the discharge speed at the intermediate position is determined by the passage cross-sectional area S5 at the intermediate position.

  As a result, when the piezoelectric element 551 is driven in a state where the diaphragm member 56 is located at the intermediate position, the ink is discharged at a higher discharge speed than the ink discharge speed at the initial position by the pressure applied by the piezoelectric element 551. Discharged. At this time, the flow path resistance is increased in the nozzle 54A portion, and the flow rate corresponding to the increased resistance is returned from the cavity 52 to the reservoir 51 side, whereby the ink weight is discharged as “medium”.

  In this way, by disposing the throttle member 56 at the intermediate position, the passage cross-sectional area S5 is narrower than the passage cross-sectional area S5 at the initial position, thereby increasing the discharge speed even when the ink weight is “medium”. It can be discharged. As a result, even when the ink weight is “medium”, the ejected ink droplets are less susceptible to the influence of external factors such as wind, and thus land on the roll paper P out of the intended position. Can be prevented, and the drawing position accuracy can be improved. Further, since discharge can be performed at a higher discharge speed, it is possible to remove foreign matters such as dust debris entering the communication path 53 from the nozzle 54A.

  As shown in FIG. 6C, when the throttle member 56 is located at the final position, the throttle portion 562 facing the nozzle 54A is located further inside the nozzle 54A than the intermediate position, and the nozzle inner surface 542A and the throttle portion outer surface 563 The shortest distance becomes narrower than the shortest distance at the intermediate position, and the ink passing cross-sectional area S5 becomes narrower than the passing cross-sectional area S5 at the intermediate position. In that case, the difference between the opening cross-sectional area S6 at the site P7 and the passing cross-sectional area S5 at the final position is further larger than the difference between the passing cross-sectional area S5 at the intermediate position. Accordingly, the discharge speed at the final position is determined by the portion of the passage cross-sectional area S5 at the final position.

  Accordingly, when the piezoelectric element 551 is driven in a state where the diaphragm member 56 is located at the final position, the ink is ejected at a higher ejection speed than the ink ejection speed at the intermediate position by the pressure applied by the piezoelectric element 551. Is discharged. At this time, the flow path resistance is further increased in the nozzle 54A portion, and the flow rate corresponding to the increased resistance is returned from the cavity 52 to the reservoir 51 side, so that the ink weight is discharged as “small”.

  In this way, by positioning the throttle member 56 at the final position, the passage cross-sectional area S5 is further narrower than the passage cross-sectional area S5 at the intermediate position, so that the discharge speed can be further increased even if the ink weight is “small”. It is possible to discharge with increased. As a result, even when the ink weight is “small”, the ejected ink droplets are less likely to be affected by external factors such as wind, and thus land on the roll paper P out of the intended position. Can be prevented, and the drawing position accuracy can be improved. In addition, since discharge can be performed at a higher discharge speed, it is possible to remove foreign matters such as dust debris that enter the communication path 53 from the nozzle 54A.

According to the embodiment described above, the following effects can be obtained.
In the fluid ejection head 50A of the present embodiment, ink is ejected by the first drive unit 55 (piezoelectric element 551) via a nozzle 54A formed in a tapered shape (tapered shape). Further, the second drive unit 57 moves the diaphragm member 56 forward and backward with respect to the nozzle 54A, and the passage sectional area S5 when the passage sectional area S5 of the ink is variable is changed to the nozzle where the passage sectional area S5 is set. The opening cross-sectional area S6 at the portion P7 in the discharge direction is made smaller than the portion P6 at 54A. Thereby, it is possible to vary the ejection speed of the ink ejected from the nozzle 54A. Therefore, the fluid ejection head 50A can improve the drawing positional accuracy and remove foreign matters such as dust debris entering the inside from the nozzle 54A.

The fluid ejection head 50 </ b> A of the present embodiment drives the second drive unit 57 in correspondence with the drive of the first drive unit 55. Thereby, the ejection speed and fluid weight of the ink to be ejected can be adjusted by combining the first drive unit 55 and the second drive unit 57.
Note that the fluid ejection head 50A of the present embodiment drives the second drive unit 57 in correspondence with the drive of the first drive unit 55, and sets the position of the throttle member 56 (throttle unit 562) to three positions (initial stage). Position, intermediate position, final position). As a result, the passage cross-sectional area S5 of the ink can be varied widely to make the passage cross-sectional area S5 smaller than the opening cross-sectional area S6 at the portion P7 in the ejection direction from the portion P6 in the nozzle 54A where the passage sectional area S5 is set. Thus, the discharge speed is changed in three stages, and the discharge amount is changed into three types. As a result, even when the ink weight is “small”, it is possible to discharge at a higher discharge speed, so that the discharged ink droplet (droplet) is less susceptible to external factors such as wind. Thus, it is possible to prevent landing on the roll paper P (print medium) that deviates from the intended position, and the drawing position accuracy can be improved. In addition, even when the ink weight is “small”, it is possible to remove foreign matters such as dust particles entering the inside from the nozzle 54 </ b> A by discharging at a high discharge speed.

  In the fluid ejection head 50A of the present embodiment, the throttle member 56 includes a throttle portion 562 having a throttle portion outer surface 563 formed in a tapered shape whose outer diameter decreases. Thereby, the aperture member 56 can be configured easily. In addition, since it becomes easier to control the ink passage cross-sectional area S5 due to the movement of the diaphragm member 56, it becomes easier to control the weight of the ejected ink.

  According to the fluid ejection head 50 of the present embodiment, the second drive unit 57 includes the piezoelectric element 571, so that the size of the second drive unit 57 can be reduced.

  According to the fluid ejection device (printer 1) of the present embodiment, the fluid ejection head 50A and the control unit 4 that controls the operations of the first drive unit 55 and the second drive unit 57 are configured. As a result, the drawing position accuracy can be improved, foreign matters such as dust marks entering the nozzle 54A from the inside can be removed, and the drawing quality can be maintained and improved.

[Fourth Embodiment]
FIG. 8 is a cross-sectional view showing a state in which foreign matter accumulated in the communication path 53 is removed in the ejection head 50A according to the fourth embodiment. FIG. 8 shows an enlarged configuration around the nozzle 54A for convenience of explanation. With reference to FIG. 8, one mode of the operation for removing the foreign matter accumulated in the communication path 53 will be described.
Note that the configuration of the ejection head 50A of the present embodiment is the same as that of the third embodiment, and thus the same reference numerals as those of the third embodiment are added.

  In the present embodiment, the control unit 4 drives only the second drive unit 57 without driving the first drive unit 55. In other words, the second drive unit 57 is driven independently of the first drive unit 55. Specifically, the control unit 4 drives the second drive unit 57 via a driving driver, and as shown in FIG. 8, the control unit 4 sets the aperture member 56 (the aperture unit 562) to the initial position in the third embodiment. Control to reciprocate continuously between the final positions.

  In FIG. 8, the position of the diaphragm member 56 at the initial position is indicated by a solid line, and the position of the diaphragm member 56 at the final position is indicated by a two-dot chain line.

  The ink filled in the communication path 53 vibrates by the continuous reciprocating movement of the throttle member 56. Due to this vibration, dust in the communication passage 53 can be caused to flow in the communication passage 53 by vibration. This makes it easier for dust dust to flow out of the nozzle 54A.

According to the embodiment described above, the following effects can be obtained.
According to the fluid ejection head 50A of the present embodiment, the first drive unit 55 is not driven, and only the second drive unit 57 is driven. Specifically, only the second drive unit 57 is driven, and the diaphragm member 56 is continuously reciprocated between the initial position and the final position in the third embodiment. Thereby, the ink in the communication path 53 is vibrated. Due to this vibration, dust particles accumulated in the communication path 53 can flow in the communication path 53. As a result, dust particles can easily flow out of the nozzle 54 </ b> A, thereby removing foreign matter.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the invention. A modification will be described below.

  In the fluid ejection heads 50 of the first and second embodiments described above, the taper angle A2 of the nozzle 54 is set smaller than the taper angle A1 of the throttle portion 562. However, the present invention is not limited to this, and the taper angle A2 of the nozzle 54 may be set larger than or equal to the taper angle A1 of the throttle portion 562, and is the same as in the first and second embodiments. The effect of can be produced.

  In the fluid discharge head 50 of the first embodiment, the taper shape of the nozzle 54 is formed in a taper shape whose inner peripheral diameter decreases in the discharge direction. However, the present invention is not limited to this, and the nozzle may be formed as a straight nozzle without being tapered. Also in this case, by driving the second drive unit 57, the diaphragm member 56 is moved forward and backward, and the ink cross-sectional area is varied widely, so that the discharge cross-sectional area is set to be ejected from the nozzle portion. It can be made smaller with respect to the opening cross-sectional area at the portion that becomes the direction. Thereby, it becomes possible to vary the discharge speed of the discharged ink, and the same effects as those of the first and second embodiments can be obtained.

  In the fluid ejection head 50 according to the first embodiment, the control unit 4 sets the position of the throttle member 56 to three positions so as to eject with three types of ink weights. However, the present invention is not limited to this. Instead, the position at which the diaphragm member 56 is moved may be set according to the number of types of ink weight to be controlled. This also applies to the third embodiment.

  In the fluid ejection head 50 of the second embodiment, the throttle member 56 (throttle portion 562) is continuously reciprocated between the initial position and the final position in the first embodiment. However, the amount of movement is not limited, and the movement distance may be longer than the initial position with reference to the final position, or the movement distance may be shorter than the initial position. This also applies to the fourth embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Printer as fluid ejection apparatus, 4 ... Control part, 5 ... Head mechanism, 50, 50A ... Fluid ejection head, 51 ... Reservoir, 52 ... Cavity, 53 ... Communication path, 54, 54A ... Nozzle, 55 ... 1st DESCRIPTION OF SYMBOLS 1 drive part, 56 ... Diaphragm member, 57 ... 2nd drive part, 542, 542A ... Nozzle inner surface, 551 ... Piezoelectric element, 562 ... Diaphragm part, 563 ... Diaphragm part outer surface, 571 ... Piezoelectric element, 572 ... Displacement expansion mechanism, S1, S5: Cross-sectional area of passage, S2, S6: Cross-sectional area of opening, P1, P6 ... part, P2, P7 ... part.

Claims (8)

A nozzle for discharging fluid;
A first driving unit that pressurizes the fluid and discharges the fluid through the nozzle;
A throttle member located inside the nozzle and formed in a tapered shape in the fluid discharge direction;
A second drive unit that moves the throttle member forward and backward in the discharge direction,
The passage cross-sectional area when the passage cross-sectional area of the fluid is varied widely by moving the throttle member forward and backward relative to the nozzle is the discharge direction from the portion of the nozzle where the passage cross-sectional area is set. A fluid discharge head characterized by being smaller than an opening cross-sectional area at a portion to be. The fluid ejection head according to claim 1,
The fluid ejection head, wherein the nozzle is formed in a tapered shape in the ejection direction. The fluid ejection head according to claim 1,
The fluid ejection head, wherein the nozzle is formed in a tapered shape in the ejection direction. The fluid ejection head according to any one of claims 1 to 3,
The fluid ejection head, wherein the first drive unit and the second drive unit are driven independently. The fluid ejection head according to any one of claims 1 to 3,
A fluid discharge head that drives the second drive unit in correspondence with the drive of the first drive unit. The fluid discharge head according to any one of claims 1 to 5,
The fluid ejection head, wherein the throttle member is formed in a tapered shape that reduces an outer diameter in the fluid ejection direction. The fluid ejection head according to any one of claims 1 to 6,
The fluid ejection head according to claim 2, wherein the second drive unit includes a piezoelectric element. The fluid ejection head according to any one of claims 1 to 7,
A fluid ejection device comprising: a control unit that controls operations of the first driving unit and the second driving unit.

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