Abstract:
There is provided an inkjet head including: a body portion ejecting ink therein by a driving of an actuator; and a rigidity reinforcing portion coupled to an outer surface of the body portion and reducing deformation of the body portion during the ejecting of the ink.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 10-2010-0016254 filed on Feb. 23, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an inkjet head, and more particularly, to an inkjet head allowing for a reduction in the deformation thereof when an actuator is driven. 
         [0004]    2. Description of the Related Art 
         [0005]    An inkjet head creates an image by ejecting ink droplets in a desired position. In recent years, an inkjet head has widely been used in industrial fields. For example, it is used to directly form a circuit pattern on a printed circuit board (PCB), create industrial graphics, or manufacture a liquid crystal display (LCD). 
         [0006]    An inkjet head is divided into a thermal transfer inkjet head ejecting ink using the generation of bubbles caused by temperature variations and a piezoelectric inkjet head ejecting ink using variations in the volume of an ink chamber by applying a driving signal to a piezoelectric element. 
         [0007]    In the case of a piezoelectric inkjet head, the size of droplets being ejected is very small, so printing quality may be influenced even by minute vibrations. When a piezoelectric element is driven, an inkjet head is instantly deformed, whereby a problem of printing quality may be caused. 
         [0008]    Accordingly, there is a need for the development of technology achieving constant printing quality by reducing the deformation of an inkjet head when a piezoelectric element is driven. 
       SUMMARY OF THE INVENTION 
       [0009]    An aspect of the present invention provides an inkjet head achieving improved printing quality by reducing the deformation of the inkjet head when a piezoelectric element is driven. 
         [0010]    According to an aspect of the present invention, there is provided an inkjet head including: a body portion ejecting ink therein by a driving of an actuator; and a rigidity reinforcing portion coupled to an outer surface of the body portion and reducing deformation of the body portion during the ejecting of the ink. 
         [0011]    The rigidity reinforcing portion may include any one of a wire, a plate, or a lattice. 
         [0012]    The rigidity reinforcing portion may be tightly coupled to side surfaces, a bottom surface, or both the side surfaces and the bottom surface of the body portion. 
         [0013]    According to another aspect of the present invention, there is provided an inkjet head including: a body portion ejecting ink therein by a driving of an actuator; a rigidity reinforcing portion coupled to an outer surface of the body portion and reducing deformation of the body portion during the ejecting of the ink; and a coupling portion to be recessed into the outer surface of the body portion such that the rigidity reinforcing portion is coupled thereto. 
         [0014]    The body portion may include an upper plate and a lower plate coupled to each other and have an ink chamber and a reservoir provided therein. An ink inlet, through which to draw ink into the reservoir, may be provided in an upper surface of the upper plate. A nozzle, through which to eject the ink, may be provided in a lower surface of the lower plate. 
         [0015]    The coupling portion may be provided to be adjacent to the nozzle in order that the rigidity reinforcing portion may do not cover the nozzle. 
         [0016]    The rigidity reinforcing portion may include any one of a wire, a plate, or a lattice to be inserted into the coupling portion. 
         [0017]    The rigidity reinforcing portion may be tightly coupled to side surfaces, a bottom surface, or both the side surfaces and the bottom surface of the body portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0019]      FIG. 1  is a perspective view illustrating an inkjet head according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 2  is a cross-sectional view taken along line A-A′ of  FIG. 1 ; 
           [0021]      FIG. 3  is a perspective view illustrating an inkjet head according to another exemplary embodiment of the present invention; 
           [0022]      FIG. 4  is a cross-sectional view taken along line A-A′ of  FIG. 3 ; 
           [0023]      FIG. 5  is a perspective view illustrating an inkjet head according to another exemplary embodiment of the present invention; and 
           [0024]      FIG. 6  is a cross-sectional view taken along line A-A′ of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0026]    The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0027]    Throughout the drawings, the same reference numerals will be used to designate the same or like elements. 
         [0028]    In addition, when one element is referred to as being “connected” to another element, it should be understood that the former can be “directly connected” to the latter, or “indirectly connected” to the latter via an intervening element. Furthermore, unless explicitly described to the contrary, the word “include” and variations such as “includes” or “including,” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
         [0029]      FIG. 1  is a perspective view illustrating an inkjet head according to an exemplary embodiment of the present invention. 
         [0030]    With reference to  FIG. 1 , an inkjet head may include a body portion  10 , a rigidity reinforcing portion  20  and an actuator  30 . 
         [0031]    The body portion  10  includes an upper plate  10   a  and a lower plate  10   b . Inside the body portion  10 , an ink chamber, a reservoir, and the like may be formed. 
         [0032]    Also, an ink inlet  18  is formed in the body portion  10  in order that ink may be drawn into the body portion  10 . 
         [0033]    The actuator  30  is mounted on the upper surface of the body portion  10  and supplies pressure to the ink chamber formed inside the body portion  10  so that the ink may be ejected through a nozzle formed in a bottom surface of the body portion  10 . 
         [0034]    Here, the actuator  30  may be formed as a piezoelectric element that converts an electrical signal generated by a driving circuit (not shown) into mechanical pressure. 
         [0035]    The rigidity reinforcing portion  20  may be coupled to the surface of the body portion  10 . 
         [0036]    Here, the rigidity reinforcing portion  20  may have the form of a wire as shown in  FIG. 1 , but is not limited thereto. Since the rigidity reinforcing portion  20  should reduce the deformation of the body portion  10 , a material thereof may be selected so as to have appropriate rigidity and elasticity. 
         [0037]    The rigidity reinforcing portion  20  having constant rigidity and elasticity is coupled to the bottom surface, the side surfaces or both the bottom surface and the side surfaces of the body portion  10  so that the deformation of the body portion  10  may be prevented. Particularly, in the case of a piezoelectric inkjet head, the body portion  10  may be deformed due to pressure produced during the driving of the actuator  30 ; however, the coupling of the rigidity reinforcing portion  20  with the body portion  10  may effectively reduce the deformation thereof. 
         [0038]    Also, the body portion  10  may include a coupling portion  22  having a recess shape such that the rigidity reinforcing portion  20  may be easily coupled to the surface of the body portion  10 . 
         [0039]      FIG. 2  is a cross-sectional view taken along line A-A′ of  FIG. 1 . 
         [0040]    With reference to  FIG. 2 , the body portion  10 , formed by coupling the upper plate  10   a  and the lower plate  10   b , has an ink chamber  14  and a reservoir  16  formed therein. The ink inlet  18  is formed in the upper surface of the upper plate  10   a  and a nozzle  12  is formed in the lower surface of the lower plate  10   b.    
         [0041]    The reservoir  16  receives ink drawn in from the outside and stores the ink. The reservoir  16  may be prepared by forming a recess having an inner space in the lower plate  10   b.    
         [0042]    The ink may be drawn from the outside to the reservoir  16  through the ink inlet  18 . The body portion  10  may include a single ink inlet, or a plurality of ink inlets in the case of the inclusion of a plurality of ink chambers respectively corresponding thereto. 
         [0043]    The reservoir  16  may be connected to the ink chamber  14  through a restrictor such that the ink stored in the reservoir  16  may be transferred to the ink chamber  14  through the restrictor. 
         [0044]    Here, since the reservoir  16  may be disposed under the ink chamber  14 , the restrictor may be formed inside the body portion  10  in a vertical direction. 
         [0045]    The ink chamber  14  may be provided under the actuator  30 . Here, a portion of the upper plate  10   a  that forms the ceiling of the ink chamber  14  serves as a vibration plate. 
         [0046]    Therefore, when a driving signal is applied to the actuator  30  in order to eject ink, the actuator  30  and the vibration plate thereunder are deformed to thereby reduce the volume of the ink chamber  14 . 
         [0047]    The reduction in the volume of the ink chamber  14  increases the pressure inside the ink chamber  14 , so that the ink inside the ink chamber  14  may be ejected to the outside through the nozzle  12 . 
         [0048]    The actuator  30  may include electrodes electrically connected to the upper and lower surfaces thereof. The actuator  30  may be formed of Plumbum Zirconate Titanate (PZT) ceramic which is a piezoelectric material. 
         [0049]    Also, the coupling portion  22  having a recess shape is formed in the lower surface of the lower plate  10   b , and the rigidity reinforcing portion  20  in the form of a wire is coupled thereto. 
         [0050]    In this embodiment as depicted in  FIG. 2 , the rigidity reinforcing portion  20  is configured to be in the form of four wires; however, the number thereof may be varied, if desired. 
         [0051]      FIG. 3  is a perspective view illustrating an inkjet head according to another exemplary embodiment of the present invention. 
         [0052]    With reference to  FIG. 3 , an inkjet head of this embodiment is the same as that of the aforementioned embodiment depicted in  FIG. 1 , except that the rigidity reinforcing portion  20  has the form of a plate. 
         [0053]    In the case of the inkjet head according to the embodiment depicted in  FIG. 3 , the rigidity reinforcing portion  20  having the form of a plate almost encloses the side surfaces and bottom surface of the body portion  10 , and thus the deformation of the body portion  10  may be effectively reduced. 
         [0054]      FIG. 4  is a cross-sectional view taken along line A-A′ of  FIG. 3 . 
         [0055]    With reference to  FIG. 4 , the rigidity reinforcing portion  20  in the form of a plate is coupled to the body portion  10  without covering the nozzle  12  formed in the bottom surface of the body portion  10 . To enable this, the coupling portion  22  is formed to be adjacent to the nozzle  12 . 
         [0056]      FIG. 5  is a perspective view illustrating an inkjet head according to another exemplary embodiment of the present invention. 
         [0057]    With reference to  FIG. 5 , an inkjet head of this embodiment is the same as that of the aforementioned embodiment depicted in  FIG. 1 , except that the rigidity reinforcing portion  20  has the form of a lattice. 
         [0058]    In the case of the inkjet head according to the embodiment depicted in  FIG. 5 , the rigidity reinforcing portion  20  having the form of a lattice encloses the side surfaces and bottom surface of the body portion  10 , and thus the deformation of the body portion  10  may be effectively reduced. 
         [0059]      FIG. 6  is a cross-sectional view taken along line A-A′ of  FIG. 5 . 
         [0060]    With reference to  FIG. 6 , the rigidity reinforcing portion  20  in the form of a lattice is coupled to the body portion  10  without covering the nozzle  12  formed in the bottom surface of the body portion  10 . 
         [0061]    Although not shown herein, the rigidity reinforcing portion  20 , may be freely selected to have a variety of forms in addition to a wire, plate, or lattice form in order that it may effectively reduce the deformation of the body portion  10 . 
         [0062]    As set forth above, according to exemplary embodiments of the invention, an inkjet head having a rigidity reinforcing portion allows for a reduction in the deformation thereof caused by the driving of a piezoelectric element, whereby printing quality is improved. 
         [0063]    While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.