JP2010125606A - Liquid jet head, liquid jet recording device, and liquid filling method for liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve (1) improvement in the space factor of a liquid jet head, (2) improvement in the recovery capacity of surplus liquid and (3) initial filling of a liquid jet recording device with simple constitution. <P>SOLUTION: The liquid jet head 10 including a jet body 23 having a jet nozzle array 31c including a plurality of jet nozzles 31a includes a jet body guard 24 formed to cover the jet nozzle array 31c. The jet body guard 24 includes a top plate part 24a arranged spaced from the surface of the jet body 23 and formed with a slit 24c facing the jet nozzle array 31c, and a sealing part 24b sealing a space between the peripheral edge part of the top plate part 24a and the jet body 23. The liquid jet head 10 also includes a suction passage 15 having a suction port 15a opened above the jet nozzle array 23c to communicate with an internal space S of the jet body guard 24 while being connected to an external suction apparatus to form the internal space S of the jet body guard 24 into a vacuum chamber R and to suck a first liquid Y overflowing into the vacuum chamber R from the jet nozzles 31a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting recording apparatus, and a liquid filling method for a liquid ejecting head, which record an image and characters on a recording medium by ejecting liquid from a liquid ejecting port.

  In general, a liquid jet recording apparatus, for example, an ink jet printer that performs various types of printing includes a transport apparatus that transports a recording medium and an ink jet head. The ink jet head used here includes a nozzle body having a nozzle row composed of a plurality of nozzle holes, a plurality of pressure generation chambers that communicate with the nozzle holes in pairs, and ink in the pressure generation chambers. And a piezoelectric actuator disposed adjacent to the pressure generation chamber, and drives the piezoelectric actuator to pressurize the pressure generation chamber, so that the ink in the pressure generation chamber is discharged from the nozzle discharge port of the nozzle hole. What is discharged is known.

  As one type of such an ink jet printer, there is known a printer that provides a carriage for moving the ink jet head in a direction perpendicular to the conveyance direction of the recording paper (recording medium) and prints on the recording paper. In this type of inkjet printer, a service station for maintenance is provided within the movable range of the inkjet head, the inkjet head is moved to this service station, the nozzle holes are cleaned, and the inkjet head is covered with a cap so that negative pressure is applied. The ink is sucked and the nozzle holes are initially filled with ink.

  Another type different from the ink jet printer is one that is used for a relatively large recording medium such as a box and prints on a recording medium that is transported by fixing an ink jet head. In this type of inkjet printer, the inkjet head cannot be moved, and there is little space for providing a service station between the inkjet head and the recording medium or below the inkjet head. For this reason, when the ink is initially filled in the pressure generating chamber, the ink is usually pressurized and filled from the ink supply system side.

  In this pressure filling, in order to prevent the ink jet head and the vicinity of the ink jet printer from being contaminated by surplus ink that drips from the nozzle hole, and also to prevent the discharge of ink after ink filling from becoming unstable. In addition, a means for removing excess ink must be taken. The same applies not only to the initial filling scene but also to the scene of collecting ink that drips on the nozzle body during normal use.

In the following Patent Document 1, an ink guide member made of a plate-like porous absorber and projecting outward from the nozzle forming surface and a block type ink absorber connected to the ink guide member are provided at the bottom of the inkjet head. An ink jet head is disclosed in which surplus ink is received by an ink guide member and guided to an ink absorber, and the guided surplus ink is absorbed by the ink absorber.
Japanese Patent Laid-Open No. 5-116338

However, the conventional technique has a problem that the ink guide member and the ink absorber are provided at the lower part of the ink jet head, so that the lower part of the ink jet head cannot be effectively used. In addition, when an inkjet printer is designed under certain restrictions, there is a problem that printing cannot be performed on the lower part of the recording medium.
Furthermore, in the conventional technology, there is a problem in that there is a limit to the amount of excess ink that can be collected because excess ink is merely absorbed by the ink absorber.

The present invention has been made in view of such circumstances, and has the following objects.
(1) The space factor of the liquid jet head is improved, and the degree of freedom in designing the liquid jet recording apparatus is improved.
(2) Improve surplus liquid recovery capability to prevent contamination with surplus liquid and stabilize liquid jet after liquid filling.
(3) The initial filling of the liquid jet recording apparatus is realized with a simple configuration.

In order to achieve the above object, the present invention employs the following means.
As a solving means related to the liquid jet head, an ejector having an ejection hole array composed of a plurality of ejection holes, a plurality of pressure generation chambers communicating with the ejection holes in pairs with the ejection holes, and the pressure generation chambers A liquid supply system for supplying the first liquid to the pressure generating chamber, and an actuator disposed adjacent to the pressure generating chamber. The actuator is driven to pressurize the pressure generating chamber, and the first liquid in the pressure generating chamber is The liquid ejecting head for ejecting from the liquid ejecting port of the ejecting hole includes an ejector guard formed so as to cover the ejecting hole row, and the ejector guard is disposed apart from the surface of the ejecting body. A top plate portion formed with a slit facing the row, and a sealing portion that seals between the peripheral portion of the top plate portion and the jet body, and a suction port is opened above the jet hole row. Inside space of the spray guard A suction channel that communicates with and is connected to an external suction device to make the inner space of the spray guard a negative pressure chamber, and sucks the first liquid that overflows from the injection hole into the negative pressure chamber; Adopt the means.

According to the present invention, surplus liquid at the time of initial filling or normal use of the liquid flows out into the negative pressure chamber communicating with the outside only through the slit, and the gas outside the negative pressure chamber passes through the slit to the negative pressure chamber. Inflow. As a result, the excess liquid moves in the negative pressure chamber in a state where it is difficult to leak out from the slit, and is sucked into the suction channel from the suction port and discharged to the outside, so that the liquid flowing out from the liquid ejection port is recovered. The space to be made can be made extremely small.
Furthermore, since the suction port is opened above the ejection hole row, the ejection hole can be arranged as far as the lowermost part of the liquid ejection head as compared with the case where the suction port is opened below the ejection hole row. As a result, the liquid can be ejected below the recording medium.
Therefore, the space factor of the liquid jet head can be improved, and the degree of freedom in designing the liquid jet recording apparatus can be improved.

Further, since the liquid can be continuously discharged by the suction flow path, the recovery capability of the excess liquid is extremely high, and even when a large amount of the excess liquid flows out, contamination with the excess liquid can be prevented. The liquid injection after the liquid filling can be stabilized.
In addition, it is not necessary to clean the forming surface of the injection port with a wiper, and without providing a service station equipped with a cleaning device such as a wiper, an injection guard, a suction channel, an external suction device, Therefore, it is possible to recover the excess liquid, so that the initial filling of the liquid jet recording apparatus can be realized with a simple configuration.

Further, as a solving means relating to the liquid ejecting head, a means is adopted in which the suction port is provided at a position not facing the slit.
According to this invention, since the air flowing in from the slit reaches the suction port after passing through the inner space, the inner space can be quickly decompressed, and the negative pressure state of the negative pressure chamber can be favorably continued. it can. As a result, it is possible to quickly collect surplus liquid and to stably collect a large amount of surplus liquid.

Further, as a solving means relating to the liquid ejecting head, a means is adopted in which a water repellent film is formed on at least the outer surface exposed to the outside of the surface of the ejector guard.
According to the present invention, even if the excess liquid leaks out from the slit, it is easily repelled by the water-repellent film and stays in the negative pressure chamber, so that the recovery capability of the excess liquid is improved and contamination due to leakage of the excess liquid is caused. Is prevented.

Further, as a solving means relating to the liquid ejecting head, a means is adopted in which a hydrophilic film is formed on an inner surface in contact with the negative pressure chamber among the surfaces of the ejector guard.
According to the present invention, the excess liquid easily flows through the negative pressure chamber and is difficult to leak from the slit to the outside, and the excess liquid repelled by the water repellent film is guided to the negative pressure chamber, so that the excess liquid flows out from the slit. It becomes easier to stay in the negative pressure chamber.

Further, as a solving means related to the liquid ejecting head, a recess portion that is recessed toward the negative pressure chamber is formed in the top plate portion of the ejector guard, and the slit is formed in a bottom surface of the recess portion. Adopt the means.
According to the present invention, since the slit is formed on the bottom surface of the recess, even when the ejector guard is in contact with the recording medium or the like, the probability of being in contact with the water-repellent film near the slit is reduced. It is possible to prevent the water film from peeling off.
Further, in the case of ejecting liquid onto the recording medium with the liquid ejection port of the liquid ejection head facing downward, even if excess liquid remains in the inner space after the negative pressure chamber is restored, It is possible to effectively prevent the excess liquid from leaking out.

Further, as a solution means related to the liquid jet head, a means is provided in which the top plate portion of the jet guard is formed with an annular projecting wall projecting toward the negative pressure chamber and annularly surrounding the slit. Is adopted.
According to this invention, since the annular liquid prevents the excessive liquid that travels on the inner surface from moving toward the slit, it is possible to prevent the excessive liquid from leaking from the slit. In particular, when ejecting liquid onto the recording medium with the liquid ejecting port of the liquid ejecting head directed downward, even if excess liquid remains in the inner space after the negative pressure chamber is restored, It is possible to effectively prevent the excess liquid from leaking out.

Further, as a solution means related to the liquid jet head, an absorber that absorbs the first liquid overflowing from the jet hole is disposed between the top plate portion of the jet guard and the jet body. Adopt the means of being.
According to this invention, since the absorber is provided between the top plate portion of the ejector guard and the ejector, excess liquid flowing out from the ejector during the initial filling of the liquid or during normal use is preliminarily absorbed by the absorber. Is absorbed by. Thereby, the recovery capability of the surplus liquid can be further improved with a simple configuration, and contamination in the vicinity of the liquid ejecting head due to the surplus liquid can be prevented.

Further, as a solving means related to the liquid ejecting head, the absorber is disposed on the ejector side between the top plate portion and the ejector, and the entire circumference of the slit as viewed from the opening direction of the slit. The surface of the absorber disposed so as to surround the injection body and facing the injection body is provided with an annular groove portion that surrounds the injection hole array and faces at least a part of the suction port. adopt.
According to the present invention, since the annular groove portion that surrounds the injection hole array and faces at least a part of the suction port is provided on the surface of the absorber that is opposed to and in contact with the injection body, the annular groove portion is the negative pressure chamber. And more negative pressure than other parts of the absorber. Thereby, the liquid absorbed by the absorber flows out into the annular groove, flows through the annular groove, and is quickly discharged from the upper suction port. Accordingly, the surplus liquid recovery capability can be further improved, and contamination of the vicinity of the liquid jet head due to the surplus liquid can be prevented with a higher effect.

Further, as a solution means related to the liquid jet recording apparatus, a means is provided that includes a liquid jet head that employs any one of the above means, and a liquid supply unit that supplies the first liquid to the liquid supply system. Is adopted.
According to the present invention, since any one of the liquid ejecting heads described above is provided, it is possible to meet various requirements for the design of the liquid ejecting recording apparatus. For example, the liquid ejecting capable of performing recording on the lower portion of the recording medium. It can be set as a recording device.
In addition, the ability to collect surplus liquid is extremely high, and even when a large amount of surplus liquid flows out, contamination by surplus liquid is prevented, and liquid jetting after liquid filling is stable, so recording on the recording medium is of high quality. And it can be made highly efficient.
In addition, it is not necessary to clean the formation surface of the injection port with a wiper, and it is possible to collect excess liquid with the injection guard, the suction flow path, and the external suction device without providing a service station. The initial filling can be realized with a simple configuration, and the entire apparatus configuration can be made compact.

Further, as a solving means related to the liquid jet recording apparatus, a means is adopted in which the liquid supply unit is configured to be able to switch and supply the first liquid and the second liquid to the liquid supply system.
According to the present invention, since two types of liquid are supplied to the liquid supply system, for example, ink and cleaning liquid are supplied to the liquid supply system to reduce labor for cleaning the liquid ejecting head and to efficiently clean the liquid supply system. Can do. Thereby, the collection | recovery capability of a surplus liquid can be recovered.

Further, as means for solving the liquid filling method of the liquid ejecting head, an ejector having an ejecting hole array composed of a plurality of ejecting holes and a plurality of pressure generating chambers communicating with the ejecting holes in pairs with the ejecting holes. A liquid supply system for supplying the first liquid to the pressure generation chamber, and an actuator disposed adjacent to the pressure generation chamber, and driving the actuator to pressurize the pressure generation chamber, The first liquid is ejected from the liquid ejection port of the ejection hole, and the ejection guard is formed so as to cover the ejection hole row, and the ejection guard is disposed away from the surface of the ejection body. A top plate portion formed with a slit facing the injection hole row; and a sealing portion that seals between a peripheral portion of the top plate portion and the jet body, and a suction port is provided above the injection hole row. Open the inside of the spray guard A suction channel that is connected to an external suction device and serves as a negative pressure chamber, and sucks the first liquid that has overflowed from the injection hole into the negative pressure chamber. A liquid filling method for a liquid jet head comprising: the first liquid is supplied to the pressure generation chamber using the liquid supply system in a state where the negative pressure chamber is set to a negative pressure from an atmospheric pressure by the external suction device. The means of pressure filling is adopted.
According to the present invention, since the air continuously flows from the slit as compared with the case where the liquid is pressurized and filled in the pressure generation chamber while the inner space is at the same pressure as the atmospheric pressure, the excess liquid leaks from the slit. In addition, since the suction port continuously discharges the excess liquid, the excess liquid does not accumulate in the inner space (negative pressure chamber) and overflow from the slit. This makes it possible to fill the liquid while preventing contamination with excess liquid, and to stabilize the liquid ejection after the liquid is filled.

Further, as a solution means related to the liquid filling method of the liquid ejecting head, a means is adopted in which the pressure filling is terminated in a state where the negative pressure chamber is set to a negative pressure from the atmospheric pressure by the external suction device.
According to the present invention, the pressure filling is finished in the state of the negative pressure chamber, and the liquid does not flow out into the negative pressure chamber. Therefore, when the pressure filling is finished in the pressure generating chamber after returning the inner space In contrast, excess liquid is less likely to leak from the slit and does not overflow from the slit. This makes it possible to fill the liquid while preventing contamination with excess liquid, and to stabilize the liquid ejection after the liquid is filled.

According to the present invention, excess liquid at the initial filling or normal use of the liquid flows out into the negative pressure chamber communicating with the outside only through the slit, and the gas outside the negative pressure chamber passes into the negative pressure chamber through the slit. Inflow. As a result, the excess liquid moves in the negative pressure chamber in a state where it is difficult to leak out from the slit, and is sucked into the suction channel from the suction port and discharged to the outside, so that the liquid flowing out from the liquid ejection port is recovered. The space to be made can be made extremely small.
Furthermore, since the suction port is opened above the ejection hole row, the ejection hole can be arranged as far as the lowermost part of the liquid ejection head as compared with the case where the suction port is opened below the ejection hole row. As a result, the liquid can be ejected below the recording medium.
Therefore, the space factor of the liquid jet head can be improved, and the degree of freedom in designing the liquid jet recording apparatus can be improved.
Further, since the liquid can be continuously discharged by the suction flow path, the recovery capability of the excess liquid is extremely high, and even when a large amount of the excess liquid flows out, contamination with the excess liquid can be prevented. The liquid injection after the liquid filling can be stabilized.
In addition, it is not necessary to clean the formation surface of the injection port with a wiper, and it is possible to collect excess liquid with the injection guard, the suction flow path, and the external suction device without providing a service station. Thus, it is possible to realize the initial filling of the liquid jet recording apparatus with a simple configuration.

Embodiments of the present invention will be described below with reference to the drawings.
(Liquid jet recording device)
FIG. 1 is a perspective view showing an ink jet recording apparatus (liquid jet recording apparatus) 1 according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the ink jet recording apparatus 1. The ink jet recording apparatus 1 is connected to a predetermined personal computer, and prints on a box D by ejecting (jetting) ink (liquid) I based on print data sent from the personal computer. It is. The ink jet recording apparatus 1 includes a belt conveyor 2 that conveys the box D in one direction, an ink discharge unit 3 that includes a plurality of ink jet heads 10, and ink (first liquid) in the ink jet head 10 as shown in FIG. Ink supply section 5 for supplying I and cleaning liquid for cleaning (second liquid) W, and suction pump 16 connected to inkjet head 10 are provided.

  The ink ejection unit 3 ejects ink I to the box D, and includes four rectangular parallelepiped housings 6 as shown in FIG. (See FIG. 2). Two housings 6 are disposed on both sides of the belt conveyor 2 in the width direction with the ink discharge surfaces 6a facing the belt conveyor 2 side. Two casings 6 respectively arranged on both sides in the width direction of the belt conveyor 2 are arranged side by side in the vertical direction and supported by support members 7 respectively. Note that an opening 6 b is formed in the ink ejection surface 6 a of the housing 6.

(Liquid jet head)
3 is a front view of the inkjet head 10, FIG. 4 is a schematic configuration diagram of the inkjet head 10 viewed from the right side, and FIG. 5 is a cross-sectional view taken along the line II of FIG.
As shown in FIG. 4, the inkjet head 10 includes a case 11, a liquid supply system 12, a head chip 20, a drive circuit board 14 (see FIG. 5), and a suction flow path 15.

  The case 11 has a thin box shape in which an exposure hole 11b is formed in the front surface 11a, and is fixed in the housing 6 with the thickness direction facing the horizontal direction and the exposure hole 11b facing the opening 6b. Has been. As shown in FIGS. 4 and 5, the case 11 has a through-hole communicating with the internal space on the back surface 11c. Specifically, the ink injection hole 11d is located at a substantially middle position in the height direction. An ink suction hole 11e is formed in the upper part. The case 11 includes a base plate 11 f that is erected and fixed to the case 11 in the internal space, and accommodates each component of the inkjet head 10.

The liquid supply system 12 communicates with the ink supply unit 5 through the ink injection hole 11d, and is schematically configured by a damper 17 and an ink flow path substrate 18.
As shown in FIG. 5, the damper 17 is for adjusting the pressure fluctuation of the ink I, and includes a storage chamber 17 a for storing the ink I. The damper 17 is fixed to the base plate 11f, and is connected to the ink intake hole 17b connected via the ink injection hole 11d and the pipe member 17d, and via the ink flow path substrate 18 and the pipe member 17e. And an ink outflow hole 17c.
As shown in FIG. 4, the ink flow path substrate 18 is a vertically formed member. As shown in FIG. 5, a flow path 18a through which the ink I flows is formed so as to communicate with the damper 17 therein. And is attached to the head chip 20.

  As shown in FIG. 5, the drive circuit board 14 includes a control circuit (not shown) and a flexible board 14a. The drive circuit board 14 has one end of a flexible substrate 14a joined to a plate electrode 28 described later and the other end joined to a control circuit (not shown) on the drive circuit board 14 so that the ceramic piezoelectric plate 21 can be formed in accordance with the print pattern. Apply voltage to The drive circuit board 14 is fixed to the base plate 11f.

(Head chip)
As shown in FIG. 6, the head chip 20 includes a ceramic piezoelectric plate (actuator) 21, an ink chamber plate 22, a nozzle body (ejection body) 23, and a nozzle guard (ejection body guard) 24. In addition, in FIG. 6, the absorber 60 mentioned later is abbreviate | omitted.

  The ceramic piezoelectric plate 21 is a substantially rectangular plate-shaped member made of PZT (lead zirconate titanate). As shown in FIGS. 6 and 7, one of the two plate surfaces 21a and 21b is formed on one plate surface 21a. A plurality of long grooves (pressure generation chambers) 26 are arranged in parallel, and each long groove 26 is isolated by a side wall 27.

  As shown in FIG. 6, the long grooves 26 extend in the short direction of the ceramic piezoelectric plate 21, and a plurality of the long grooves 26 are arranged in parallel over the entire length in the longitudinal direction of the ceramic piezoelectric plate 21. As shown in FIG. 7, each long groove 26 has a rectangular cross section along the thickness direction of the piezoelectric actuator. The bottom surface of each long groove 26 has a front flat surface 26a extending from the front side surface 21c of the ceramic piezoelectric plate 21 to a substantially central portion in the short side direction, and a groove depth from the rear portion of the front flat surface 26a toward the rear side surface. Is formed of an inclined surface 26b that gradually becomes shallow and a rear flat surface 26c that extends from the rear portion of the inclined surface 26b toward the rear side surface. Each long groove 26 is formed by a disk-shaped die cutter.

  A plurality of side walls 27 are juxtaposed along the longitudinal direction of the ceramic piezoelectric plate 21 to divide the long grooves 26. A plate-like electrode 28 for applying a driving voltage is extended across the short direction of the ceramic piezoelectric plate 21 on the opening side (the plate surface 21a side) of the long groove 26 on both wall surfaces of each side wall 27. The plate electrode 28 is formed by vapor deposition from a known oblique direction. The plate-like electrode 28 is joined to the flexible substrate 14a described above.

  As shown in FIG. 5, such a ceramic piezoelectric plate 21 has a rear surface side of the plate surface 21b fixed to the edge of the base plate 11f, and the extending direction of the long groove 26 is directed to the exposure hole 11b.

Returning to FIG. 6 and FIG. 7, the ink chamber plate 22 is a substantially rectangular plate-like member like the ceramic piezoelectric plate 21, and the longitudinal dimension thereof is substantially the same as the dimension of the ceramic piezoelectric plate 21. The dimensions in the short direction are short. The ink chamber plate 22 includes an open hole 22 c that penetrates in the thickness direction and is formed along the longitudinal direction of the ink chamber plate 22.
The ink chamber plate 22 can be formed of a ceramic plate, a metal plate, or the like, but a ceramic plate having an approximate thermal expansion coefficient is used in consideration of deformation after joining with the ceramic piezoelectric plate 21.

As shown in FIG. 6, the ink chamber plate 22 has a ceramic piezoelectric plate from the plate surface 21 a side so that the front side surface 22 a forms a butt surface 25 a that is flush with the front side surface 21 c of the ceramic piezoelectric plate 21. It is joined to the plate 21. In this joined state, the open holes 22c expose the plurality of long grooves 26 of the ceramic piezoelectric plate 21 throughout, open all the long grooves 26 outward, and the long grooves 26 are in communication with each other.
As shown in FIG. 5, the ink flow path substrate 18 is attached to the ink chamber plate 22 so as to cover the open hole 22c, and the flow path 18a of the ink flow path substrate 18 and each long groove 26 communicate with each other. .

As shown in FIG. 5, the nozzle body 23 is configured by attaching a nozzle plate 31 to a nozzle cap 32.
As shown in FIG. 6, the nozzle plate 31 is a thin plate-like and elongated member made of polyimide, and a plurality of nozzle holes (injection holes) 31 a penetrating in the thickness direction are arranged to form a nozzle row ( An injection hole array) 31c is configured. More specifically, the same number of nozzle holes 31 a as the long grooves 26 are formed on the same line at the middle position in the short direction of the nozzle plate 31 and at the same intervals as the long grooves 26.
Of the two plate surfaces of the nozzle plate 31, a water-repellent film having water repellency for preventing adhesion of the ink I and the like on the plate surface where the nozzle discharge port (nozzle outlet) 31 b for discharging the ink I opens. The other plate surface is a joint surface between the abutting surface 25 a and the nozzle cap 32.
The nozzle hole 31a is formed using an excimer laser device.

The nozzle cap 32 is a member having a shape obtained by scraping the outer peripheral edge of one of the two frame surfaces of the frame plate-shaped member, and includes a thin plate-shaped outer frame portion 32a and an outer frame. The inner frame portion 32h that is thicker than the portion 32a, the inner frame portion 32b that is thicker than the middle frame portion 32h, and the middle portion of the inner frame portion 32b that penetrates in the thickness direction and extends in the longitudinal direction. It is a member provided with the long hole 32c which exists, and the discharge hole 32d (refer FIG. 4) penetrated in the thickness direction in the one end part of the outer frame part 32a. In other words, the middle frame portion 32h and the inner frame portion 32b protrude stepwise in the thickness direction from the outer frame surface 32e of the outer frame portion 32a, and the cross-sectional contour in the thickness direction faces the elongated hole 32c. The outer frame portion 32a, the middle frame portion 32h, and the inner frame portion 32b are stepped in order.
A nozzle plate 31 is attached to the inner frame surface 32f extending in the same direction as the outer frame surface 32e so as to close the long hole 32c, and extends in a direction orthogonal to the outer frame surface 32e and the outer frame surface 32e. The nozzle guard 24 is in contact with the inner side surface 32i. In the middle frame portion 32h, a surface extending in the same direction as the outer frame surface 32e is defined as a middle frame surface 32n.

Such a nozzle body 23 is accommodated in the internal space of the case 11 so that the discharge hole 32d of the nozzle cap 32 is located on the upper side (see FIG. 3), and is fixed to the case 11 and the base plate 11f (FIG. 5). reference).
In this state, a part of the ceramic piezoelectric plate 21 and the ink chamber plate 22 is inserted into the long hole 32 c, and the butting surface 25 a is butted against the nozzle plate 31.

  With such a configuration, when a predetermined amount of ink I is supplied from the storage chamber 17a in the damper 17 to the ink flow path substrate 18, the supplied ink I is sent into the long groove 26 through the opening hole 22c. It is supposed to be. The gap between the ink chamber plate 22 and the long groove 26 generated on the rear flat surface 26c side (see FIG. 7) of the long groove 26 is sealed with a sealing material.

(Nozzle guard)
The nozzle guard 24 is a substantially box-shaped member made of stainless steel, and is formed by press molding. The nozzle guard 24 includes a top plate portion 24a formed in a rectangular plate shape, and a sealing portion 24b extending from a peripheral portion of the top plate portion 24a in a direction substantially orthogonal to the plate surface direction.

The top plate portion 24a has a plate surface that is substantially the same size as the inner frame surface 32f, and includes a slit 24c that extends in the longitudinal direction at an intermediate portion in the short direction of the top plate portion 24a. The slit 24c is formed to be approximately equal to or slightly longer than the length of the nozzle row 31c, and both end portions (upper end portion 24i, lower end portion 24j) are formed in a circular shape.
The width dimension of the slit 24c is set to about 1.5 mm with respect to the nozzle diameter of 40 μm of the nozzle hole 31a. The width of the slit 24c can be set to a negative pressure by the suction pump 16, and the upper limit is the width that allows the ink I in the space S to flow upward against gravity. It is desirable that the lower limit is set to a width dimension at which the ink I does not overflow from the slit 24c during the initial filling.
Further, the upper end 24i and the lower end 24j are formed in a circle with a diameter slightly larger than the width dimension described above.

  The nozzle guard 24 has a hydrophilic film 24g formed of titanium coating on an inner surface 24e facing inward, and an inner surface 24e and an outer surface 24f facing away from the inner surface 24e, and an inner surface of the slit 24c with fluorine resin coating or Teflon. A water repellent film 24h is formed by (registered trademark) plating.

  In such a nozzle guard 24, the top plate portion 24a covers the inner frame portion 32b and the discharge hole 32d (see FIG. 3), and the inner surface 24e of the sealing portion 24b and the inner side surface 32i of the middle frame portion 32h. The annular end 24d is adhered to the outer frame surface 32e with an adhesive so as to be in contact with the nozzle cap 32 (see FIG. 5). In this state, the nozzle row 31c is covered via the space (inner space) S so that the slit 24c faces the nozzle row 31c and does not face the discharge hole 32d. In other words, in the opening direction of the slit 24c, the nozzle discharge port 31b is covered so as to face the nozzle row 31c from the slit 24c and not to face the discharge hole 32d (see FIG. 3).

  In the nozzle guard 24, the distance between the top plate portion 24a and the nozzle plate 31 can be set to a negative pressure by the suction pump 16, and the ink I in the space S flows upward against gravity. It is desirable to set the distance within the range where the upper limit is the possible distance and the lower limit is the distance at which the ink I does not overflow from the slit 24c during the initial filling of the ink I.

  As shown in FIG. 4, the suction channel 15 is configured such that one end of a tube tube serving as a suction port 15a is fitted and fixed in the discharge hole 32d, and the other end is connected to the ink suction hole 11e. Yes. As described above, the suction port 15a opens at a position that does not face the slit 24c.

  The suction pump 16 is connected to the ink suction hole 11e via a tube. During operation, the suction pump 16 sucks the ink I guided upward from below against the air and gravity in the space S, so that the space S becomes a negative pressure chamber R. The suction pump 16 stores the ink I sucked into the waste liquid tank E (see FIG. 2).

(Absorber)
Here, as shown in FIGS. 3 to 5, the surplus overflows from the nozzle hole 31 a inside the nozzle guard 24 (space S) and between the top plate portion 24 a of the nozzle guard 24 and the nozzle cap 32. An absorber 60 that absorbs the ink Y is disposed. Specifically, the absorber 60 is a member having a rectangular shape in plan view and having a dimension substantially the same as the dimension in the surface direction of the top plate portion 24a of the nozzle guard 24, as shown in FIGS. This is a member in which a substantially rectangular parallelepiped recess 60b capable of accommodating the nozzle plate 31 and the middle frame portion 32h of the nozzle cap 32 is formed. A slit 60a having substantially the same shape as the slit 24c of the nozzle guard 24 is formed so as to avoid the nozzle row 31c, and an annular groove 60k surrounding the entire circumference of the slit 60a is formed at the central portion in the width direction of the recess 60b. ing.
As shown in FIG. 8, the annular groove 60 k has a circular groove 60 m formed with a size larger than the opening area of the discharge hole 32 d on one end side in the longitudinal direction of the absorber 60.

In the space direction between the nozzle guard 24 and the nozzle cap 32 (the left-right direction in FIG. 4), the absorber 60 is placed between the end surface of the nozzle plate 31 and the middle frame surface 32n of the middle frame portion 32h of the nozzle cap 32. It is stuck so as to abut. That is, the absorber 60 is disposed so as to surround the nozzle row 31c along the surface direction of the nozzle plate 31, and in other words, the suction groove 15a of the nozzle cap 32 so that the circular groove 60m faces the discharge hole 32d. Are arranged so as to cover in a plan view (viewed from the opening direction of the slit 24c).
In this state, the annular groove 60 k constitutes the tubular flow path F with the middle frame surface 32 n of the middle frame portion 32 h of the nozzle cap 32.

  As a material of the absorber 60, a porous film such as PVA (polyvinyl alcohol) (for example, Kanebo Belita A series) or high-density polyethylene powder (for example, manufactured by Asahi Kasei (Sunfine)) is preferably used. Yes. Further, the absorber 60 may be attached to the end surface of the nozzle plate 31 or the middle frame surface 32n of the middle frame portion 32 or both the end surface of the nozzle plate 31 and the middle frame surface 32n using an adhesive. In this case, for example, it is preferable to attach a high-viscosity adhesive made of epoxy or the like.

Returning to FIG. 2, the ink supply unit 5 includes an ink tank 51 in which the ink I is stored, a cleaning liquid tank 52 in which the cleaning liquid W is stored, a switching valve 53 that can switch between two flow paths, and the ink I or A pressurizing pump 54 that pressurizes and supplies the cleaning liquid W to the inkjet head 10 and an open / close valve 55 that can open and close the flow path are provided.
The ink tank 51 communicates with the pressurizing pump 54 via the supply pipe 57a, the switching valve 53 and the supply pipe 57c, and the cleaning liquid tank 52 communicates with the pressure pump 54 via the supply pipe 57b, the switching valve 53 and the supply pipe 57c, respectively. That is, the switching valve 53 is connected to the supply pipes 57a and 57b as inflow pipes and the supply pipe 57c as outflow pipes.

  The pressurizing pump 54 is connected to the supply pipe 57 c and communicates with the inkjet head 10 through the supply pipe 57 d, and supplies the ink I or the cleaning liquid W flowing from the supply pipe 57 c to the inkjet head 10. The pressurizing pump 54 is configured so that fluid does not flow when not in operation, and has a function of an on-off valve.

  The open / close valve 55 is connected to a supply pipe 57e that communicates with the supply pipe 57c and serves as an inflow pipe, and a supply pipe 57f that communicates with the supply pipe 57d and serves as an outflow pipe. That is, when the opening / closing valve 55 is opened, the supply pipes 57e and 57f function as bypass pipes for the pressure pump 54.

  Next, the operation of the ink jet recording apparatus 1 having the above configuration will be described. In the following description, a case where printing is performed on the box D after the ink I is initially filled in the inkjet head 10 will be described, and further, a case where the inkjet head 10 is cleaned will be described.

(Ink initial filling)
First, as shown in FIGS. 4 and 9, the suction pump 16 of the inkjet head 10 is operated, and the suction pump 16 sucks air in the space S from the suction port 15a through the suction flow path 15 (in FIG. 9). Time T0). At this time, external air flows into the space S from the slit 24c, but the air is sucked after reaching the suction port 15a after passing through the space S, thereby depressurizing the space S. Then, after the predetermined time T1 has elapsed, the space S becomes the negative pressure chamber R in which the negative pressure is sufficiently lower than the atmospheric pressure.

  After the space S becomes the negative pressure chamber R, the ink supply unit 5 pressurizes and fills the inkjet head 10 with the ink I (time T2 in FIG. 9). At this time, the ink supply unit 5 is set as follows. That is, as shown in FIG. 2, the supply pipe 57a and the supply pipe 57c are brought into communication with each other by the switching valve 53, the open / close valve 55 is closed, and the supply pipe 57e and the supply pipe 57f are shut off. In this state, the pressurizing pump 54 is operated. The pressure pump 54 injects the ink I from the ink tank 51 into the ink injection hole 11d of the inkjet head 10 through the supply pipes 57a, 57c, and 57d.

  As shown in FIGS. 4 and 5, the ink I injected into the ink injection hole 11d flows into the storage chamber 17a via the ink intake hole 17b of the damper 17, and then flows through the ink outlet hole 17c. It flows out to the flow path 18a of the road substrate 18. And the ink I which flowed into the flow path 18a flows in into each long groove | channel 26 via the open hole 22c.

The ink I that has flowed into each long groove 26 flows to the nozzle hole 31a side, reaches the nozzle hole 31a, and then flows out from the nozzle hole 31a as excess ink Y, as shown in FIG. When the surplus ink Y starts to flow out, the amount thereof is small, so the surplus ink Y is sucked by the suction port 15a and flows upward on the nozzle plate 31 (upward in the direction of gravity). Most of the excess ink Y is absorbed by the absorber 60 in the middle of flowing upward.
At this time, even if surplus ink Y flows out from the nozzle hole 31a, a gap is formed between the top plate portion 24a and the absorber 60 and air flows from the slit 24c. Therefore, it adheres to the periphery of the slit 60 a formation surface of the absorber 60 and is absorbed by the absorber 60.

  The surplus ink Y absorbed by the absorber 60 is sucked by the suction port 15a, moves upward in the absorber 60, flows out of the circular groove 60m, and the suction port 15a facing the circular groove 60m. Is sucked into the suction flow path 15 and discharged to the waste liquid tank E.

  Further, the annular flow path F formed by the annular groove 32k and the inner frame surface 32n of the nozzle cap 32 communicates with the suction port 15a, and is compared with the other part of the absorber 60 and the negative pressure chamber R. More negative pressure. For this reason, out of the excess ink Y absorbed by the absorber 60, the excess ink Y in the vicinity of the tubular groove portion 32k flows out into the tubular flow path F, and then quickly flows through the tubular flow path F from the suction port 15a. It is sucked into the suction channel 15 and discharged to the waste liquid tank E (see FIG. 8).

  If the surplus ink Y flows out excessively and the absorption amount of the absorber 60 is saturated, the surplus ink Y is not only on the nozzle plate 31 but also on the nozzle guard 24 as shown in FIG. It also flows upward on the inner surface 24e. At this time, air continuously flows from the slit 24c into the negative pressure chamber R, and the excess ink Y hardly flows out from the slit 24c. As shown in FIG. 10C, the amount of surplus ink Y that flows on the inner surface 24e in the vicinity of the slit 24c increases locally, and a part of the surplus ink Y resists the air flowing from the slit 24c. Even if it reaches the vicinity of the outer surface 24f, it is repelled by the water repellent film 24h formed on the outer surface 24f. The repelled ink I is guided to the hydrophilic film 24g formed on the inner surface 24e and returned to the negative pressure chamber R again.

At the lower end 24j of the slit 24c, surface tension acts on the ink I at the contour of the circular lower end 24j (boundary between the outer surface 24f and the lower end 24j). At the lower end 24j, a strong surface tension acts on the ink I, and the balance of the surface tension is maintained so that the surface of the ink I is not destroyed and does not leak outside. Further, similarly to the above, the water-repellent film 24 h formed on the outer surface 24 f and the hydrophilic film 24 g formed on the inner surface 24 e are guided to return to the negative pressure chamber R.
In this way, the excess ink Y flowing out from the nozzle hole 31a is continuously discharged to the waste liquid tank E.

  As shown in FIG. 9, the pressurization pump 54 is stopped after a predetermined time T3, and the pressurization and filling of the ink I is completed. As the pressurizing pump 54 stops, the surplus ink Y does not flow out from the nozzle hole 31a, and the surplus ink Y remaining in the negative pressure chamber R is discharged from the suction port 15a to the waste liquid tank E via the absorber 60. Is done.

  And the suction pump 16 is stopped after predetermined time T4 progress. After completion of the filling of the ink I, the long groove 26 is filled with the ink I as shown in FIG. Note that the space S is restored to the same pressure as the atmospheric pressure again (see FIG. 9).

(When printing)
Next, an operation when printing is performed on the box D will be described. First, the setting of the ink supply unit 5 will be described. In other words, as shown in FIG. 2, the supply pipe 57a and the supply pipe 57c are brought into communication with each other by the switching valve 53, and the open / close valve 55 is opened to connect the supply pipe 57e and the supply pipe 57f. In this state, the pressurization pump 54 is inactivated, and the supply pipe 57c and the supply pipe 57d are not communicated with each other via the pressurization pump 54. In this state, the ink I is injected into the ink injection hole 11d of the inkjet head 10 through the supply pipes 57a, 57c, 57e, 57f, and 57d.

The belt conveyor 2 is driven with the ink supply unit 5 set as described above (see FIG. 1), and the box D is conveyed in one direction. When passing, that is, when passing in front of the nozzle plate 31 (nozzle hole 31 a), the ink ejection unit 3 ejects ink droplets toward the box body D.
Specifically, based on print data input from an external personal computer, the drive circuit board 14 selectively applies a voltage to a predetermined plate electrode 28 corresponding to the print data. Thereby, the volume of the long groove 26 corresponding to the plate electrode 28 is reduced, and the ink I filled in the long groove 26 is discharged toward the box body D from the nozzle discharge port 31b.
When the ink I is ejected, the long groove 26 becomes negative pressure, so that the ink I is filled into the long groove 26 through the supply pipes 57a, 57c, 57e, 57f, and 57d.

  In this way, the ceramic piezoelectric plate 21 of the inkjet head 10 is driven according to the image data, and ink droplets are ejected from the nozzle holes 31a and land on the box D. Thus, an image (character) is printed at a desired position of the box D by continuously ejecting ink droplets from the inkjet head 10 while moving the box D.

(When cleaning)
Next, an operation at the time of cleaning the inkjet head 10 will be described. First, the setting of the ink supply unit 5 will be described. That is, as shown in FIG. 2, the supply pipe 57b and the supply pipe 57c are communicated by the switching valve 53, the open / close valve 55 is closed, and the supply pipe 57e and the supply pipe 57f are closed. In this state, the pressurizing pump 54 is operated. The pressurizing pump 54 injects the cleaning liquid W from the cleaning liquid tank 52 into the ink injection hole 11d of the inkjet head 10 through the supply pipes 57b, 57c, and 57d.
As in the initial filling, the cleaning liquid W flows out from the nozzle hole 31a through the long groove 26 and the like. Specifically, the cleaning liquid W flowing out from the nozzle hole 31 a flows upward on the inner surface 24 e of the nozzle guard 24 and the nozzle cap 32 and is absorbed by the absorber 60 disposed on the end face of the nozzle plate 31. Is done. The cleaning liquid W absorbed by the absorber 60 flows upward through the absorber 60 after being absorbed by the absorber 60, and is sucked from the suction port 15a. At this time, the cleaning liquid W transmitted through the absorber 60 flows above the absorber 60 together with the ink I remaining in the absorber 60. That is, since the inside of the absorber 60 is also cleaned by the cleaning liquid W, the ink I does not remain in the absorber 60.
If the inkjet recording apparatus 1 is not used for a long period of time, the ink I filled in the long groove 26 is dried and cured. In this case, if the inside of the inkjet head 10 is filled with the cleaning liquid W as in the cleaning, the inkjet recording apparatus 1 can be stored for a long period of time.

As described above, according to the ink jet recording apparatus 1, the excess ink Y moves in the negative pressure chamber R in the ink jet head 10 in a state in which it is difficult to leak out from the slit 24c, and is sucked into the suction flow path 15 from the suction port 15a. Since the ink I is discharged to the outside, the space for collecting the ink I flowing out from the nozzle discharge port 31b can be made extremely small.
Furthermore, since the suction port 15a is opened above the nozzle row 31c, the nozzle hole 31a can be arranged to the bottom of the inkjet head 10 as compared with the case where the suction port 15a is opened below the nozzle row 31c. Thereby, the ink I can be discharged below the box D.
Therefore, the space factor of the inkjet head 10 can be improved, and the degree of freedom in designing the inkjet recording apparatus 1 can be improved.

In addition, according to the inkjet head 10, since a large amount of excess ink Y can be continuously discharged by the suction flow path 15, the recovery capability of the excess ink Y is improved, contamination by the excess ink Y is prevented, and the ink is discharged. The ejection of the ink I after filling I can be stabilized. For this reason, the printing with respect to the solid D of the inkjet recording device 1 can be made high quality and highly efficient.
Further, according to the inkjet head 10, it is possible to realize the initial filling of the inkjet recording apparatus 1 with a simple configuration without providing a service station. For this reason, the whole apparatus structure of the inkjet recording apparatus 1 can be made compact.

  In addition, the suction port 15a is disposed without facing the slit 24c, and the air flowing in from the slit 24c reaches the suction port 15a after passing through the space S (negative pressure chamber R). The pressure can be reduced, and the negative pressure state of the negative pressure chamber R can be favorably continued. Thereby, it is possible to quickly collect the surplus ink Y and to collect a large amount of surplus ink Y stably.

Further, since the water repellent film 24h is formed on the outer surface 24f, even if the surplus ink Y in the negative pressure chamber R tries to flow outside through the slit 24c, it is repelled by the water repellent film 24h and becomes negative pressure. It becomes easy to stay in the room R.
Further, since the hydrophilic film 24g is formed on the inner surface 24e, the ink I can easily flow through the negative pressure chamber R, and the surplus ink Y repelled by the water-repellent film 24h is guided to the negative pressure chamber R, so that the surplus ink. Since Y tends to stay in the negative pressure chamber R, it is possible to prevent the excess ink Y from flowing out of the slit 24c with a high probability.
Furthermore, since the slit 24c is formed so as not to cover the nozzle row 31c, the negative pressure environment can be further increased. That is, the space S can be quickly decompressed, and the negative pressure state of the negative pressure chamber R can be favorably continued.

Further, since the lower end 24j of the slit 24c is circular, the surface of the ink I maintained by the surface tension at the lower end 24j is not easily destroyed, and the excess ink Y is likely to stay in the negative pressure chamber R. Specifically, first, the ink I that has reached the lower end 24j of the slit 24c contacts the lower end 24j. At this time, surface tension acts on the ink I at the contour of the circular lower end 24j (the boundary between the outer surface 24f and the lower end 24j). Here, since the liquid (ink I) exists in a substantially spherical shape in an environment in which the external force does not act strongly, if the end of the slit 24c is rectangular, the surface of the substantially spherical body maintained by the surface tension is There is a possibility that the ink I leaks outside the slit 24c.
On the other hand, when the end portion of the slit 24c is circular as in the present embodiment, the surface of the liquid (ink I) maintained by the surface tension is not destroyed, and the negative pressure does not leak out at the lower end portion 24j. It is easy to stay in the room R. Further, since the water repellent film 24h is formed on the outer surface 24f in the same manner as described above, the ink I about to leak can be retained in the negative pressure chamber R.
When such a configuration is adopted, as described above, even if the surplus ink Y tries to leak out from the slit 24c, the ink I tends to stay in the negative pressure chamber R at the lower end 24j of the slit 24c, so that the surplus ink Contamination due to leakage of Y can be prevented, and the recovery capability of excess ink Y can be improved.

  Further, since the absorber 60 is provided between the top plate portion 24a of the nozzle guard 24 and the nozzle body 23, the excess ink Y flowing out from the nozzle body 23 during the initial filling of the ink I or during normal use is preliminarily stored. Absorbed by the absorber 60. Thereby, the recovery capability of the surplus ink Y can be further improved with a simple configuration, and contamination in the vicinity of the inkjet head 10 due to the surplus ink Y can be prevented.

  In addition, since the annular groove 60k that surrounds the nozzle row 31c and faces at least a part of the suction port 15a is provided on the surface of the absorber 60 that faces and contacts the nozzle body 23, the annular groove 60k is negative pressure. Compared with the other part of the chamber R and the absorber 60, it becomes a negative pressure more. Thereby, the surplus ink Y absorbed by the absorber 60 flows out into the annular groove 60k, flows through the annular groove 60k, and is quickly discharged from the upper suction port 15a. Accordingly, it is possible to further improve the collecting ability of the surplus ink Y, and to prevent the surplus ink Y from contaminating the vicinity of the inkjet head 10 with a higher effect.

  Further, the ink supply unit 5 is configured to be able to switch and supply the ink I and the cleaning liquid W, and the ink I and the cleaning liquid W are supplied to the liquid supply system 12, so that the labor for cleaning the inkjet head 10 is reduced. In addition, the inkjet head 10 can be efficiently cleaned.

Further, as described above, in the present embodiment, the space S (negative pressure chamber R) is formed using the nozzle guard 24 formed so as to cover the nozzle row 31c, and the excess ink Y is discharged from the suction port 15a. It features a configuration. Here, the characteristics of this configuration will be described below.
In this configuration, the space S becomes the negative pressure chamber R in which the negative pressure is sufficiently lower than the atmospheric pressure, and the ink I that has flowed into the negative pressure chamber R is difficult to flow toward the slit 24c. Is started. Therefore, when the nozzle guard 24 and the space S are not formed, the air is continuous from the slit 24c as compared with the case where the long groove 26 is pressurized and filled with the space S in the same pressure as the atmospheric pressure. Therefore, it is difficult for excess ink Y to leak from the slit 24c. Further, since the suction port 15a continuously discharges the surplus ink Y, the surplus ink Y does not accumulate in the space S (negative pressure chamber R) and does not overflow from the slit 24c.
Further, in the state where the negative pressure chamber R is set, the pressurization and filling are finished, and the liquid does not flow out into the negative pressure chamber R, so that compared to the case where the long groove 26 is filled with pressure after the space S is restored. The excess ink Y is difficult to leak from the slit 24c and does not overflow from the slit 24c. Accordingly, it is possible to fill the ink I while preventing contamination by the excess ink Y, and it is possible to stabilize the ejection of the ink I after filling.

(Modification)
Hereinafter, specific modifications of the inkjet head 10 will be described with reference to the drawings. In addition, about the thing of the structure similar to the inkjet head 10, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 11A is a view showing an inkjet head 80 showing a modification of the inkjet head 10. As shown in FIG. 11A, the nozzle guard 24 of the ink jet head 80 has a recess 24x that is recessed toward the negative pressure chamber R in the top plate 24a. The recess 24x is formed by press molding (rolling), and a slit 24c is formed on the bottom surface of the recess 24x. Accordingly, even when the nozzle guard 24 is in contact with the box D, the probability that the water repellent film 24h in the vicinity of the slit 24c contacts the box D is reduced, and the water repellent film 24h is prevented from peeling off. can do.
Further, when the ink I is ejected onto the recording medium with the nozzle ejection port 31b of the inkjet head 80 facing downward, it is assumed that the surplus ink Y remains in the space S after the negative pressure chamber R is restored. Also, it is possible to effectively prevent the excess ink Y from leaking from the slit 24c.

  FIG. 11B is a diagram showing an inkjet head 90 showing a modification of the inkjet head 10. As shown in FIG. 11B, the nozzle guard 24 of the inkjet head 90 is formed with an annular protruding wall 24y that protrudes toward the negative pressure chamber R and surrounds the slit 24c in an annular shape. As a result, when the ink I is discharged to the box D with the nozzle discharge port 31b of the inkjet head 90 facing downward, the excess ink Y remains in the space S after the negative pressure chamber R is restored. However, the surplus ink Y can be prevented from reaching the slit 24c along the inner surface 24e, and the surplus ink Y can be prevented from leaking from the slit 24c.

FIG. 11C is a view showing an inkjet head 100 showing a modification of the inkjet head 10. As shown in FIG. 11C, the nozzle guard 24 of the inkjet head 100 is formed with a recess 24x and an annular protruding wall 24y by press molding. Thereby, it is possible to prevent the water repellent film 24h from being peeled off, and when the ink I is discharged to the box D with the nozzle discharge port 31b of the ink jet head 100 directed downward, the excess ink Y from the slit 24c. Can be prevented from leaking.
In addition, if it is press molding, the hollow part 24x and the cyclic | annular protrusion wall 24y can be formed simultaneously, and a productive efficiency will become favorable.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In addition, about the thing of the structure similar to 1st embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted. FIG. 12 is a front view and a side view of the main part showing an inkjet head 200 according to the second embodiment of the present invention. In the present embodiment, the shape of the absorber and the location of the absorber are different from those of the first embodiment described above.

As shown in FIG. 12, the inkjet head 200 includes an absorber 160 having a rectangular shape in plan view and having a size substantially the same as the size of the top plate portion 24 a in the surface direction.
A slit 160a is formed in the central portion of the absorbent body 160 in the width direction so as to surround the nozzle row 31c in the same shape as the slit 24c of the nozzle guard 24.
The absorber 160 is affixed to the entire surface of the top plate portion 24 a exposed in the space S, and a gap is formed between the absorber 160 and the nozzle plate 31 and the nozzle cap 32.

According to this configuration, by arranging the absorber 160 on the top plate portion 24a side, the surplus ink Y overflowing from the nozzle holes 31a is reliably absorbed in the front stage of the slit 24c formed in the top plate portion 24a. 160 is absorbed. Thereby, it is possible to prevent the excess ink Y from leaking out of the slit 24c.
Further, even when the ink I is initially filled with the ink jet head 200 facing downward, the overflowing excess ink Y can be prevented from leaking out of the slit 24c through the negative pressure chamber R.

  Note that the operation procedure shown in the above-described embodiment, various shapes and combinations of the constituent members, and the like are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, the nozzle body 23 is composed of the nozzle plate 31 and the nozzle cap 32, and the annular end 24d of the nozzle guard 24 is attached to the nozzle cap 32, but the suction port 15a is a space. You may make it adhere to the nozzle plate 31 on condition that it is opened by S.

  In the above-described embodiment, the suction port 15a is fitted into the discharge hole 32d formed in the nozzle cap 32. However, the discharge hole 32d may be formed in the nozzle plate 31 or the nozzle guard 24. The suction flow path 15 may be connected to the discharge hole 32d, and the discharge hole 32d may be used as a suction port.

In the above-described embodiment, the water repellent film 24h is formed by fluororesin coating or Teflon (registered trademark) plating. However, a water repellent sheet may be attached or a water repellent may be applied.
In the above-described embodiment, the hydrophilic film 24g is formed by titanium coating. However, gold plating may be applied, or an alkaline chemical may be applied.

  In the embodiment described above, the inkjet recording apparatus 1 is configured with the inkjet head 10 fixed, but the inkjet recording apparatus 1 may be configured by moving the inkjet head 10. That is, if the ink-jet head 10 is employed, an ink-jet recording apparatus that does not require a cap for suctioning with negative pressure can be realized.

  In the above-described embodiment, the arrangement direction of the nozzle row 31c of the ink jet head 10 is directed to the direction of gravity, and the opening direction of the nozzle hole 31a is directed to the horizontal direction. It is not limited to the direction. The opening direction of the nozzle holes 31a may be directed in the direction of gravity, or the extending direction of the nozzle rows 31c may be directed in the horizontal direction.

  In the above-described embodiment, the suction pump is operated at the time of initial filling and cleaning. However, the ink I may drip from the nozzle hole 31a even during printing, and even if such ink I is collected. Good.

  In the above-described embodiment, the recess 24x and the annular projecting wall 24y are formed by press molding, but may be formed by other processing methods such as cutting.

  Moreover, in embodiment mentioned above, although the absorbers 60 and 160 were illustrated, the shape of the absorber and its arrangement | positioning are not restricted to this. For example, the entire space S may be configured to be occupied by the absorber, or may be configured to be disposed only on the lower side.

1 is a perspective view showing an inkjet recording apparatus 1 in an embodiment of the present invention. In the embodiment of the present invention, it is a schematic configuration diagram of the ink jet recording apparatus 1 viewed from the right side, and is a diagram showing a part of the configuration in cross-section. 1 is a front view of an inkjet head 10 in an embodiment of the present invention. In the embodiment of the present invention, it is a schematic configuration diagram of the ink jet recording apparatus 1 viewed from the right side, and is a diagram showing a part of the configuration in cross-section. FIG. 5 is a cross-sectional view taken along line II in FIG. 4 in the embodiment of the present invention. 4 is an exploded perspective view of the head chip 20 in the embodiment of the present invention. FIG. 4 is an exploded perspective view showing details of a ceramic piezoelectric plate 21 and an ink chamber plate 22 in the embodiment of the present invention. FIG. In embodiment of this invention, it is the II-II sectional view taken on the line in FIG. In embodiment of this invention, it is the figure which showed the relationship between the operation timing of the suction pump 16 and the pressurization pump 54, and the space S (negative pressure chamber R). In the embodiment of the present invention, it is an enlarged cross-sectional view showing a main part of the operation of the head chip 20 during initial filling. It is a figure which shows the modification of the inkjet head 10 in embodiment of this invention, Comprising: It is a principal part enlarged view which shows the inkjet heads 80,90,100. FIG. 12A is a front view of the inkjet head 200 in the embodiment of the present invention, and FIG. 12B is a side view of the main part of the inkjet head 200.

Explanation of symbols

1. Inkjet recording apparatus (liquid jet recording apparatus)
10, 80, 90, 100, 200 ... Inkjet head (liquid ejecting head)
12 ... Liquid supply system 15 ... Suction channel 15a ... Suction port 16 ... Suction pump (aspirator)
21 ... Ceramic piezoelectric plate (actuator)
23 ... Nozzle body (injection body)
24 ... Nozzle guard
24a ... Top plate portion 24b ... Sealing portion 24c ... Slit 24e ... Inner surface 24f ... Outer surface 24g ... Hydrophilic film 24h ... Water-repellent film 24x ... Recessed portion 24y ... Annular protruding wall 26 ... Long groove (pressure generating chamber)
31a ... Nozzle hole (injection hole)
31b ... Nozzle outlet (liquid outlet)
31c ... Nozzle row (jet hole row)
60, 160 ... absorber 60k ... annular groove I ... ink (first liquid)
R ... Negative pressure chamber S ... Space (inside space)
W ... Cleaning liquid (second liquid)

Claims (12)

An injection body having an injection hole array composed of a plurality of injection holes, a plurality of pressure generation chambers communicating with the injection holes in pairs with the injection holes, and a liquid supply for supplying the first liquid to the pressure generation chambers A system and an actuator disposed adjacent to the pressure generating chamber,
In the liquid ejecting head that drives the actuator to pressurize the pressure generating chamber and ejects the first liquid in the pressure generating chamber from the liquid ejecting port of the ejecting hole.
A spray guard formed so as to cover the spray hole array, the spray guard being spaced from the surface of the spray body and having a slit facing the spray hole array; and A sealing portion that seals between the peripheral portion of the top plate portion and the ejector,
A suction port opens above the row of injection holes and communicates with the inner space of the spray guard, and is connected to an external suction device to make the inner space of the spray guard a negative pressure chamber. A liquid ejecting head comprising: a suction flow path for sucking the first liquid overflowing into the negative pressure chamber.   The liquid ejecting head according to claim 1, wherein the suction port is provided at a position not facing the slit.   3. The liquid jet head according to claim 1, wherein a water repellent film is formed on at least an outer surface exposed to the outside of the surface of the jet guard.   4. The liquid ejecting head according to claim 1, wherein a hydrophilic film is formed on an inner surface of the ejector guard that is in contact with the negative pressure chamber. 5. In the top plate portion of the spray guard, a hollow portion that is recessed toward the negative pressure chamber side is formed,
5. The liquid ejecting head according to claim 1, wherein the slit is formed on a bottom surface of the hollow portion.   6. The annular projecting wall according to claim 1, wherein an annular projecting wall projecting toward the negative pressure chamber and annularly surrounding the slit is formed on the top plate portion of the ejector guard. The liquid jet head according to one item.   The absorber which absorbs the said 1st liquid which overflowed from the said injection hole is arrange | positioned between the said top-plate part of the said injection body guard, and the said injection body. The liquid jet head according to any one of the above. The absorber is disposed on the ejector side between the top plate portion and the ejector, and is disposed so as to surround the entire circumference of the slit as viewed from the opening direction of the slit.
The annular groove part which surrounds the said injection hole row | line | column and opposes at least one part of the said suction port is provided in the surface of the absorber which opposes and contacts the said injection body. Liquid jet head. A liquid ejecting head according to any one of claims 1 to 8,
A liquid jet recording apparatus comprising: a liquid supply unit that supplies the first liquid to the liquid supply system.   The liquid jet recording apparatus according to claim 9, wherein the liquid supply unit is configured to switch and supply the first liquid and the second liquid to the liquid supply system. An injection body having an injection hole array composed of a plurality of injection holes, a plurality of pressure generation chambers communicating with the injection holes in pairs with the injection holes, and a liquid supply for supplying the first liquid to the pressure generation chambers A system and an actuator disposed adjacent to the pressure generating chamber,
Driving the actuator to pressurize the pressure generation chamber, causing the first liquid in the pressure generation chamber to be ejected from the liquid ejection port of the ejection hole;
A spray guard formed so as to cover the spray hole array, the spray guard being spaced from the surface of the spray body and having a slit facing the spray hole array; and A sealing portion that seals between the peripheral portion of the top plate portion and the ejector,
A suction port opens above the row of injection holes and communicates with the inner space of the spray guard, and is connected to an external suction device to make the inner space of the spray guard a negative pressure chamber. A liquid filling method for a liquid ejecting head, comprising a suction flow path for sucking the first liquid overflowing into the negative pressure chamber,
The liquid ejecting head, wherein the first liquid is pressurized and filled to the pressure generating chamber using the liquid supply system in a state where the negative pressure chamber is set to a negative pressure from atmospheric pressure by the external suction device. Liquid filling method.   The liquid filling method for a liquid ejecting head according to claim 11, wherein the pressurizing and filling is terminated in a state where the negative pressure chamber is set to a negative pressure from an atmospheric pressure by the external suction device.

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