JP4792890B2 - Inkjet recording head and printing apparatus therefor - Google Patents

Description

The present invention relates to an ink jet recording head and the printing device ejects from the nozzle openings of the ink droplets.

  Various types of laminated ink jet recording heads are used in which a flow path to a nozzle opening such as an ink supply unit and a pressure generation chamber common to each thin plate material is formed and then laminated (for example, Patent Documents). 1). In this configuration, the flow path from the pressure generation chamber to the nozzle opening is formed by laminating a plurality of thin plate materials. However, the recording head with such a configuration can eliminate bubbles in the flow path leading to the nozzle opening with respect to the cross-sectional width of the pressure generating chamber, but the flow path leading to the nozzle opening is long, and pressure loss occurs in the process. Becomes larger and it is impossible to earn a sufficient flow velocity. For this reason, it is not easy to remove bubbles remaining in the pressure generating chamber having a sufficiently large volume with respect to the elongated channel, particularly bubbles at the corners on the nozzle opening side. In addition, a plurality of thin plate materials are stacked and the flow path is gradually communicated with the nozzle openings, but bubbles easily remain in the stepped portions of the respective communicating portions.

  In order to improve this, at the same time, in order to reduce the size and increase the nozzle mounting density, a plurality of thin plate materials partially forming a series of ink flow paths from the ink supply section to the nozzle through the pressure generation chamber are formed on the orifice plate. A so-called multilayer ink jet recording head configured by laminating in order from the back is employed (see, for example, Patent Document 2). Each thin plate material is formed with an ink supply opening, a pressure generation chamber, or an ink flow path opening to the nozzle, which are sequentially stacked on the back surface of the nozzle plate.

  In this recording head, not only the head itself can be made small, but also the nozzle mounting density can be increased by alternately arranging the pressure generating chambers in a staggered manner. However, the ink flow path from the pressure generating chamber to the nozzle is configured such that the communication holes provided in the thin plate material are shifted and at least three thin plates are stacked to gradually communicate with the nozzle opening holes. Therefore, fine bubbles mixed in the ink enter and stay in the corners formed in each thin plate material. In particular, if the contact angle between the ink and each flow path wall is high, the remaining bubbles are not easily removed, which adversely affects the ejection characteristics of the ink droplets, and in some cases the ink droplets do not eject. Yes. Furthermore, since the pressure generating chambers are alternately arranged in a zigzag pattern, when driving using an expansion / contraction type laminated piezoelectric element, the piezoelectric elements must also be arranged in a zigzag pattern, which is difficult to process. .

  Also, an ink jet head has been proposed in which a flow path connecting a pressure generating chamber and a nozzle opening is laminated on a single silicon wafer (see, for example, Patent Document 3). When fine adjustment of the amount is performed or when the discharge amount is changed by changing the nozzle diameter, it is necessary to re-create the communication flow path again. Further, in this configuration, since the common ink chambers are arranged on the side where the pressure generating chambers arranged in a staggered manner face each other, the nozzle opening rows are arranged substantially in two rows, so that the head becomes large.

Japanese Patent No. 2606955

Japanese Patent Laid-Open No. 7-195585

JP 2002-205394 A

The present invention has been made in view of such a problem, and the object of the present invention is to reduce the nozzle mounting density while minimizing the retention of bubbles in the ink flow path from the pressure generation chamber to the nozzle opening. It is an object of the present invention to provide a new laminated ink jet recording head and a printing apparatus for the same.

In order to solve the above-described problems, the present invention connects a nozzle plate having a plurality of nozzle openings arranged in at least one row, a communication path plate having a communication channel corresponding to the nozzle openings, and the communication channel. that a chamber plate having a pressure generating chamber, the ink jet recording head configured by laminating together a diaphragm plate for sealing the pressure generating chamber, when from the diaphragm plate side viewed the chamber plate , the pressure generating chamber, against phase across the nozzle opening of the first column, the longitudinal direction perpendicular to the direction of the nozzle openings of the first column, between the nozzle opening adjacent the center line parallel to the longitudinal direction is arranged to position the center of the said communication passage plate, one end portion of the nozzle opening side of the pressure generating chamber, said nozzle opening Opening hole serving as the communication passage for communicating the mouth, said at one row and two columns so as to face each other across the nozzle opening, the predetermined angle with respect to a center line parallel to the longitudinal direction of the pressure generating chamber are arranged in a zigzag pattern with an inclination, and the longitudinal length Saga said longitudinal direction of the pressure generating chamber length Halfbeak rather short and long longitudinal width of the pressure generating chamber of the opening hole of the opening hole narrower than the width, and depth of the opening hole is mainly characterized and go shallow than the depth of the pressure generating chamber.

Another feature of the present invention, the communication path plate is processed molded thin metal plate by etching or precision press method in Rukoto.

Another feature of the present invention, the communication path plates is in Rukoto such than at least one plate.

Another feature of the present invention, the printing apparatus is in Rukoto provided with the ink jet recording head

A position where an elongated pressure generating chamber arranged across a plurality of nozzle openings arranged in at least one row is positioned substantially at the center between the adjacent nozzle openings and is opposed to each other on a substantially center line in the longitudinal direction of the pressure generating chamber. Are arranged in a staggered manner and alternately connected to adjacent nozzle openings, and the communication flow path is at least Since it is formed of a single thin plate material, bubbles do not remain in the flow path portion up to the nozzle opening, and the reliability of ink droplet ejection can be improved.

  In addition, the pressure generation chambers are arranged on the same center line extension, and the communication flow paths are alternately arranged in a staggered pattern so as to communicate with the nozzle openings. Mounting density can be improved. Furthermore, two rows of piezoelectric elements corresponding to the pressure generating chambers can be processed simultaneously with two rows facing each other. As a result, the recording head can be reduced in size.

  In addition, since the width of the communication flow path is made narrower than the width of the pressure generating chamber and the tolerance of deviation due to dimensional error when thin plate materials are stacked can be increased, variations in ink droplet ejection characteristics can be reduced.

  In order to improve the mounting density of the nozzles while suppressing the retention of bubbles as much as possible in the ink flow path from the pressure generating chamber to the nozzle openings, the nozzles are arranged with a plurality of nozzle openings arranged in a row. An elongate pressure generating chamber is positioned substantially at the center between the nozzle openings and is disposed at a position facing each other on a substantially center line in the longitudinal direction of the pressure generating chamber, and one end of the pressure generating chambers facing each other on the nozzle opening side The communication flow paths connected to the sections are arranged in a staggered manner and alternately connected to adjacent nozzle openings, and the communication flow paths are realized by molding at least one thin plate material.

  FIG. 1 is a partially exploded perspective view showing an embodiment of a multilayer ink jet recording head according to the present invention, and FIG.

  The ink jet recording head 1 of the present invention includes a nozzle plate 10 having a plurality of nozzle openings 11 in at least one row, a communication path plate 20 having a communication flow path 21 communicating with the nozzle openings 11, a restrictor 32, and pressure generation. The chamber plate 30 having the opening hole 33 that also serves as the chamber 31, the thin diaphragm plate 40 that seals the pressure generating chamber 31 and the restrictor 32, and the diaphragm plate 40 in order to greatly displace only the pressure generating chamber 31 portion. A filter having a support plate 50 having an opening hole in the ink reservoir 52 common to the region 51 held as the vibration plate 41, and a filter 61 provided to prevent foreign matter from entering the flow path to each nozzle opening 11. Plate 60, a flow path substrate 5 comprising the flow path substrate 5, and holding the flow path substrate 5, and from the outside Having a high rigidity plate 70 having a common ink chamber 71 for introducing the ink reservoir. A piezoelectric actuator kumi 80 having a plurality of divided piezoelectric elements 81 is fixed to the opening groove 72 formed in the high-rigidity plate 70 so as to contact the diaphragm 40.

  Here, the nozzle plate 10 is drilled with high accuracy in order to obtain straightness of flight of ink droplets. Specifically, it is formed by a nickel electroforming method or a method of drilling a stainless steel thin plate by a precision press method.

  The communication passage plate 20 is formed with a plurality of communication passages 21 in which the elongated opening holes are arranged in two rows and the opening hole rows alternately cross each other in a zigzag pattern. It is formed to be inclined with respect to the arrangement. And the nozzle opening hole 11 is located in the one side where the opening hole row | line | column of the communication flow path 21 cross | intersected alternately.

  The chamber plate 30 is opened so that the elongated opening holes 33 serving as the flow paths of the pressure generating chamber 31 and the restrictor 32 are arranged in two rows, and the opening holes 33 in each row are opposed to the extension of the center line in the longitudinal direction. It has been. The pitch of the opening holes 33 is twice the pitch of the nozzle openings 11 arranged on the nozzle plate 10. Further, the center position of the opening hole 33 is formed so as to substantially match the center position between the nozzle openings 11. And the opening hole 33 is connected to the other side of the communication flow path 21 on the opposite side of each row.

  The communication flow path plate 20 and the chamber plate 30 described above are formed by processing a thin stainless steel plate by an etching method or a precision press method.

  The diaphragm plate 40 for sealing the opening hole 33 is formed of a stainless plate made of a thin plate of about 15 μm or less or a nickel material by an electroforming method. Alternatively, it may be a thin plastic film.

  The support plate 50 has an opening hole in an area used as the diaphragm 41 of the diaphragm plate 40 and an area to be a common ink chamber 71. The support plate 50 is also formed by processing a thin stainless steel plate by an etching method or a precision press method.

  The high-rigidity plate 70 can be easily formed by cutting a stainless bar or the like.

  When forming the opening holes facing each other opened in the chamber plate 30 or the support plate 50 by a precision press method, the holes may be formed by sequentially feeding each with a punch having the shape of the opening hole, Opening with two punches facing each other can halve the number of man-hours to make holes, and at the same time, the opening holes facing each other can be formed at the same time, so each facing opening hole has the same center line extension It can be formed to be placed on top.

  Next, the flow channel configuration according to the present invention will be described in detail. FIG. 3 is a rear view in which the plates above the diaphragm plate 40, the piezoelectric element actuator kumi 80, and the high-rigidity plate 70 side are removed. The communication flow path 21 on the communication path plate 20 from the front end of the pressure generation chamber 31 arranged so as to face each other on substantially the same center line toward the nozzle opening 11 is configured with a slight inclination. Yes. The communication channels 21 are arranged in a staggered manner so as to cross each other in the vicinity of the nozzle openings 11 and are configured to be alternately connected to the nozzle openings 11 arranged in almost one row. At this time, the position of the pressure generating chamber 31 is set at a substantially intermediate position between the nozzle openings 11. Thereby, the arrangement density of the nozzle openings 11 can be doubled without increasing the arrangement pitch of the pressure generating chambers 31. Furthermore, since the partition width between the pressure generating chambers 31 can be increased, the partition rigidity can be increased, and crosstalk between adjacent nozzles due to structural deformation can be reduced.

  In addition, the width of the communication channel 21 is narrower than the width of the pressure generation chamber 31. Thereby, when the chamber plate 30 and the communication path plate 20 are laminated and bonded, a deviation due to dimensional tolerance can be allowed. This becomes more important in order to stabilize the discharge of the droplets as the channel pitch becomes narrower. Furthermore, the length of the communication channel 21 is shorter than the pressure generation chamber 31, and the depth thereof is shallower than the pressure generation chamber 31. As a result, when the ink is filled in the flow path or when bubbles remaining in the flow path are removed, the ink is sucked from the nozzle opening 11 and the flow rate in the communication flow path 21 is reduced during the so-called head maintenance operation. It is possible to increase the flow rate of the flow path from the pressure generation chamber 31 to the nozzle opening 11 and to easily remove bubbles remaining in the flow path.

  FIG. 4 is a perspective view showing the structure and manufacturing process of the piezoelectric actuator kumi 80 used in the flow path structure of the present invention.

  Two rod-shaped piezoelectric bodies 85 in which conductive materials 82 and piezoelectric materials 83 are alternately stacked are fixed to one end surface of the support substrate 86 in parallel. An external electrode 84 is formed on the longitudinal surface of the piezoelectric body 85 so as to be electrically connected to the conductive material 82 layer inside the piezoelectric body 85. A common electrode 87 is formed at the end of the support substrate 86, and a groove 90 is formed at the center thereof. Between the two piezoelectric bodies 85 so that the external electrode 84 of the piezoelectric body 85 and the common electrode 87 are electrically connected. The groove is filled with a conductive adhesive 89a. On the other hand, the electrode 88 which becomes the individual electrode of the support substrate 86 is connected to the external electrode 84 of the piezoelectric body 85 by the conductive adhesive 89b (FIG. 4A). In the case of this example, the common electrode 88 and the individual electrode 87 of the support substrate 86 are printed in advance by a screen printing method or the like.

  Next, the two piezoelectric bodies 85 are cut into a comb-teeth shape at a predetermined pitch using a slicer such as a dacing saw or a wire saw. Thereby, the individual electrode 88 side is individually separated including the conductive adhesive b, and the common electrode 87 side can maintain the state where the conductive adhesive 89a in the groove 90 of the support substrate 86 is connected. It has become. As a result, the piezoelectric elements 81 separated from each other can operate as individual actuators (FIG. 4B).

  The piezoelectric elements 81 separated in a comb shape are processed at the same pitch so as to correspond to the pressure generation chamber 21. Finally, the individual electrodes 88 and the common electrode 87 are connected to the flexible cable 91 to form the piezoelectric actuator kumi 80 (FIG. 4C).

  In this embodiment, two piezoelectric bodies are attached to one support substrate 86. However, as shown in FIG. 5, a piezoelectric actuator 180 formed of one support substrate 186 and one row of piezoelectric bodies 185 is supported intermediately. You may make it tie through the member 192. FIG. By doing in this way, it becomes possible to process simultaneously the piezoelectric element 81 corresponding to the pressure generation chamber 31 which mutually opposed, and the inexpensive piezoelectric actuator cum 180 can be provided.

  In the present example described above, the pressure generating chamber is constituted by one thin plate material. However, as shown in FIG. 6, the chamber plate 30b having the pressure generating chamber 31b of the thin plate material is replaced with the communication path plate 20 and the chamber plate 30. The flow path may be formed by stacking between the two. Thereby, the rigidity of the flow path substrate 5 constituting the flow path is increased, and the force propagated through the ink in the pressure generating chamber 31 as the piezoelectric element 81 expands and contracts can be maintained.

  According to the ink jet recording head of the present invention, the nozzle openings can be densified and a compact head configuration is possible, so that high-speed printing is possible and fine ink droplets can be ejected, resulting in high-definition print quality. The application can be expanded from the office use printing apparatus to the industrial printing field.

1 is a perspective view showing an ink jet recording head of the present invention. 2 is a partial cross-sectional view of a flow path portion of the ink jet recording head of the present invention. FIG. It is a combination top view of the nozzle plate of this invention, a flow-path plate, and a chamber plate. It is a figure which shows the actuator manufacturing method of the inkjet recording head of this invention. It is another Example of the piezoelectric actuator used for this invention. FIG. 6 is a plan view showing a recording head channel portion according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 5 Flow path board | substrate 10 Nozzle plate 11 Nozzle opening 20 Communication path plate 21 Communication flow path 30 Chamber plates 31 and 31b Pressure generating chamber 32 Restrictor 33 Open hole 40 Diaphragm plate 41 Diaphragm plate 50 Support plate 51 Open hole 52 Common Ink reservoir 60 Filter plate 61 Filter 70 High rigidity plate 71 Common ink chamber 72 Opening groove 80 Piezoelectric actuator 81 Piezoelectric element 82 Conductive material 83 Piezoelectric material 87 Common electrode 88 Individual electrodes 89a and 89b Conductive adhesive 90 Flexible cable

Claims (4)

A nozzle plate having a plurality of nozzle openings arranged in at least one row;
A communication path plate having a communication channel corresponding to the nozzle opening;
A chamber plate having a pressure generating chamber to connect to said communication passage,
In an ink jet recording head configured by laminating a diaphragm plate for sealing the pressure generation chamber,
When viewing the chamber plate from the diaphragm plate side,
The pressure generating chamber is
Relative across the one row of nozzle openings,
The direction perpendicular to the direction of the nozzle openings of the first column as the longitudinal direction, are arranged so as to position the center of the between the nozzle opening adjacent the center line parallel to the longitudinal direction,
In the communication path plate,
One end portion of the nozzle opening side of the pressure generation chamber, wherein the communication flow path to become open hole for communicating the nozzle openings,
In two rows so as to face each other across the nozzle openings in the one row,
Arranged in a staggered manner with a predetermined angle of inclination with respect to a center line parallel to the longitudinal direction of the pressure generating chamber ,
And wherein the longitudinal direction of the opening hole long saga longitudinal direction of the pressure generating chamber length Halfbeak rather short,
And the width in the longitudinal direction of the opening hole is narrower than the width in the longitudinal direction of the pressure generating chamber ,
And an ink jet recording head depth of the opening hole, wherein the go shallow than the depth of the pressure generating chamber.   2. The ink jet recording head according to claim 1, wherein the communication path plate is formed by processing a metal thin plate by an etching method or a precision press method.   The ink jet recording head according to claim 1, wherein the communication path plate includes at least one plate.   A printing apparatus comprising the ink jet recording head according to any one of claims 1 to 3.

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