Abstract:
The present invention relates to an ink cartridge for an inkjet printer, the ink cartridge comprising a head chip of a print head to be surface-mounted on an FPCB by means of BGA so as to have each contact terminal, which is formed on the FPCB and the head chip, to be formed over a relatively wide area and therefore not require a high level of integration technology. Therefore, the ink cartridge enables easy manufacturing of the FPCB and the head chip and lowering of manufacturing cost. Also, since relatively low precision needs to be maintained during the mounting of the head chip on the FPCB such that each contact terminal comes into contact, the ink cartridge enables more convenient and faster manufacturing of the print head.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the national stage for International Patent Cooperation Treaty Application PCT/KR2015/003062, filed Mar. 27, 2015, which claims priority from Korean Patent Application No. 10-2014-0093845, filed Jul. 24, 2014, in the Korean Intellectual Property Office. The entire contents of said applications are incorporated herein by reference for all purposes. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an ink cartridge for an inkjet printer, and more particularly, to an ink cartridge for an inkjet printer, in which since each of contact terminals formed on a flexible printed circuit board (FPCB) and a head chip of a print head is formed on a large area by surface-mounting the head chip on the FPCB in a ball grid array (BGA) manner, a high level of integration technology is not required, hence the FPCB and the head chip are easily manufactured and manufacturing costs thereof are decreased, since a low level of precision needs to be maintained while mounting the head chip on the FPCB such that the contact terminals contact each other, the print head is conveniently and quickly manufactured, and since a high level of precise minute manufacturing technology is not required by disposing the contact terminal formed on the FPCB to have optimum space efficiency, the ink cartridge is easily manufactured and the head chip and the FPCB are further easily connected to each other. 
     Background Art 
     Generally, an ink cartridge used in an inkjet printer includes an ink fountain in which ink is stored and a head unit ejecting ink, wherein print is performed as ink is ejected from the head unit onto a paper according to a print command of the printer. 
       FIG. 1  is a perspective view schematically illustrating a structure of a general ink cartridge for an inkjet printer according to a related art, and  FIG. 2  is a perspective view schematically illustrating a structure of a general print head according to a related art. 
     Generally, as shown in  FIG. 1 , an ink cartridge for an inkjet printer includes a housing body  100  storing ink in an internal space and a print head  200  mounted on the housing body  100  to discharge the ink stored in the housing body  100 . 
     The print head  200  includes a flexible printed circuit board (FPCB)  210  combined to one side of the housing body  100 , and a head chip  220  including a plurality of ejection nozzles for discharging the ink and mounted on the FPCB  210 . Pattern circuits (not shown) for controlling operations of the head chip  220  is formed on the FPCB  210 , and the head chip  220  performs an operation for accurately discharging the ink while exchanging an electric signal with a printer body through the FPCB  210 . 
     As shown in  FIG. 2 , the head chip  220  may be mounted on the FPCB  210  as a plurality of chip contact terminals  222  formed at an edge of one side edge of the print head  200  and a plurality of board contact terminals  212  formed on the FPCB  210  contact each other. 
     In more detail, a head chip mounting portion  211  that is a region on which the head chip  220  is mountable is formed at one side of the FPCB  210 , and the plurality of board contact terminals  212  are formed at one side edge of the head chip mounting portion  211  on locations corresponding to the chip contact terminals  222  of the head chip  220 . When the head chip  220  is accommodated on the head chip mounting portion  211  of the FPCB  210  according to such a structure, the chip contact terminals  222  of the head chip  220  and the board contact terminals  212  of the FPCB  210  contact each other, and at this time, the head chip  220  is mounted on the FPCB  210  by soldering the terminals. 
     Here, the plurality of chip contact terminals  222  and the plurality of board contact terminals  212  are formed in relatively narrow sections respectively in the head chip  220  and the FPCB  210 , and in addition, the pattern circuits (not shown) respectively connected to the board contact terminals  212  are formed in the FPCB  210 . 
     Accordingly, while manufacturing the print head  200  of the ink cartridge, the plurality of chip contact terminals  222  and the plurality of board contact terminals  212  need to be formed in very narrow sections, and thus a high level of a precise integration technology is required. The necessity of such a high level of an integration technology is further increasing according to a recent upward trend of print resolution. Also, while connecting the head chip  220  to the FPCB  210 , a high level of a precise connection technology is also required since connection locations need to be accurately maintained such that the board contact terminals and the chip contact terminals  222  are correspondingly connected to each other. 
     Accordingly, it is very difficult and complicated to manufacture the ink cartridge, and in addition, highly precise equipment is required to manufacture the ink cartridge, and thus manufacturing costs are high. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     One or more embodiments of the present invention provide an ink cartridge for an inkjet printer, in which since each of contact terminals formed on a flexible printed circuit board (FPCB) and a head chip of a print head is formed on a large area by surface-mounting the head chip on the FPCB in a ball grid array (BGA) manner, a high level of integration technology is not required, hence the FPCB and the head chip are easily manufactured and manufacturing costs thereof are decreased, and since a low level of precision needs to be maintained while mounting the head chip on the FPCB such that the contact terminals contact each other, the print head is conveniently and quickly manufactured. 
     One or more embodiments of the present invention provide an ink cartridge for an inkjet printer, in which since a high level of precise minute manufacturing technology is not required by disposing a contact terminal formed on an FPCB to have optimum space efficiency, the ink cartridge is easily manufactured and a head chip and the FPCB are further easily connected to each other. 
     Technical Solution 
     According to an aspect of the present invention, there is provided an ink cartridge for an inkjet printer, the ink cartridge including: a housing body storing ink in an internal space; and a print head mounted on the housing body such as to discharge the ink stored in the housing body, wherein the print head includes a flexible printed circuit board (FPCB) combined to one side of the housing body, and a head chip including a plurality of ejection nozzles to discharge ink and mounted on the FPCB, wherein the head chip is mounted on the FPCB in a ball grid array (BGA) manner. 
     The FPCB may include a head chip mounting portion in which a plurality of board contact terminals are formed in the BGA manner in an inner region such that the head chip is mounted in the BGA manner, and the head chip may be mounted on the head chip mounting portion in the BGA manner as a plurality of chip contact terminals are formed in the BGA manner at locations corresponding to the plurality of board contact terminals. 
     A plurality of pattern circuits may be formed on the FPCB to be respectively connected to the plurality of board contact terminals, and the plurality of pattern circuits may be continuously formed throughout the inner region and an outer region of the head chip mounting portion. 
     The plurality of board contact terminals may be spaced apart from each other at regular intervals along a first line passing through a center portion of the head chip mounting portion and second lines that are parallel to the first line and are bilaterally symmetrical to each other based on the first line, wherein the board contact terminals disposed along the first line and the board contact terminals disposed along the second lines may be misaligned in a direction perpendicular to the first line. 
     The two adjacent board contact terminals disposed along the first line and one board contact terminal from among the board contact terminals disposed along the second lines may be disposed in a shape of an isosceles triangle in which a section between the two adjacent board contact terminals disposed along the first line is a base line. 
     A height h of the isosceles triangle may be lower than a height h′ of an equilateral triangle of which a length of one side is same as the base line. 
     The plurality of pattern circuits respectively connected to the plurality of board contact terminals may include parallel portions that are parallel to the first line in the inner region of the head chip mounting portion, and slope portions extending from one ends of the parallel portions in a direction slantly crossing the first line. 
     Some of the plurality of pattern circuits respectively connected to the plurality of board contact terminals may be formed in a direction in which the slope portions cross sections between the plurality of board contact terminals. 
     Advantageous Effects 
     According to the present invention, since each of contact terminals formed on a flexible printed circuit board (FPCB) and a head chip of a print head is formed on a large area by surface-mounting the head chip on the FPCB in a ball grid array (BGA) manner, a high level of integration technology is not required, hence the FPCB and the head chip are easily manufactured and manufacturing costs thereof are decreased, and since a low level of precision needs to be maintained while mounting the head chip on the FPCB such that the contact terminals contact each other, the print head is conveniently and quickly manufactured. 
     Also, since a high level of precise minute manufacturing technology is not required by disposing the contact terminal formed on the FPCB to have optimum space efficiency, an ink cartridge is easily manufactured and the head chip and the FPCB are further easily connected to each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view schematically illustrating a structure of a general ink cartridge for an inkjet printer according to a related art, 
         FIG. 2  is a perspective view schematically illustrating a structure of a general print head according to a related art, 
         FIG. 3  is a perspective view schematically illustrating a structure of an ink cartridge for an inkjet printer, according to an embodiment of the present invention, 
         FIG. 4  is a perspective view schematically illustrating a structure of a print head, according to an embodiment of the present invention, 
         FIG. 5  is an exemplary view of a shape of a flexible printed circuit board (FPCB), according to an embodiment of the present invention, 
         FIG. 6  is an enlarged view schematically illustrating an arrangement structure of a board contact terminal and a pattern circuit with respect to an inner region of a head chip mounting portion of the FPCB of  FIG. 5 , 
         FIG. 7  is a view schematically illustrating an arrangement structure of a chip contact terminal of a head chip, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Best Mode 
     Hereinafter, one or more embodiments of the present invention will now be described with reference to accompanying drawings. First, in drawings, like reference numerals denote like elements. Also, in the description of the present invention, certain detailed explanations of related art are omitted when it is deemed that they may unnecessarily obscure the essence of the invention. 
       FIG. 3  is a perspective view schematically illustrating a structure of an ink cartridge for an inkjet printer, according to an embodiment of the present invention, and  FIG. 4  is a perspective view schematically illustrating a structure of a print head, according to an embodiment of the present invention. 
     As shown in  FIG. 3 , the ink cartridge for the inkjet printer, according to an embodiment of the present invention includes a housing body  300  formed in a container shape to store ink in an internal space, and a print head  400  mounted on the housing body  300  to externally discharge the ink stored in the internal space of the housing body  300 . 
     The print head  400  includes a flexible printed circuit board (FPCB)  410  combined to one side of the housing body  300 , and a head chip  420  including a plurality of ejection nozzles  423  (refer to  FIG. 7 ) for discharging ink. The head chip  420  is mounted on the FPCB  410  and performs an operation while exchanging an electric signal with a printer body (not shown). 
     Here, the head chip  420  is mounted on the FPCB  410  in a ball grid array (BGA) manner according to an embodiment of the present invention. BGA is one of technologies of mounting a chip on a surface of a PCB, wherein hemispherical contact terminals, such as solder, are formed on a chip and a board and are connected to each other, and is an advantageous surface mounting technology in terms of space efficiency since a contact pin or lead protruding along an edge of the chip is not required. 
     In detail, the FPCB  410  includes a head chip mounting portion  411  including a plurality of board contact terminals  412  in a BGA manner in an inner region such that the head chip  420  is mounted in a BGA manner, and the head chip  420  includes a plurality of chip contact terminals in a BGA manner at locations corresponding to the board contact terminals  412  to be mounted on the head chip mounting portion  411  in a BGA manner. 
     In other words, the FPCB  410  includes, as a region on which the head chip  420  is mountable, the head chip mounting portion  411  having the same or similar shape and size as the head chip  420 , and the plurality of board contact terminals  412  are formed in the inner region of the head chip mounting portion  411 . A plurality of chip contact terminals  422  are correspondingly formed at one side surface of the head chip  420 . The board contact terminal  412  and the chip contact terminal  422  may be formed via soldering, and may have a hemispherical shape. Also, the chip contact terminals  422  of the head chip  420  and the board contact terminals  412  of the FPCB  410  are formed on corresponding locations to correspondingly contact each other while the head chip  420  is mounted on the head chip mounting portion  411  of the FPCB  410 . 
     According to such a structure, the print head  400  of the ink cartridge according to an embodiment of the present invention has excellent space efficiency compared to the related art since the contact terminals  412  and  422  respectively formed in the FPCB  410  and the head chip  420  are formed in relatively large areas, and accordingly, a high level of a precise integration technology is not required unlike the related art, and thus not only manufacturing of the print head  400  is easy, but also manufacturing costs are decreased. Also, individual sizes of the contact terminals  412  and  422  may be relatively largely increased, and accordingly, the contact terminals  412  and  422  may correspondingly contact each other even if a high level of precision with respect to location alignment is not maintained while mounting the head chip  420  on the FPCB  410 , and thus manufacturing processes may be conveniently performed. 
     Next, arrangement structures of the contact terminals  412  and  422  respectively formed on the FPCB  410  and the head chip  420  will be described in detail. 
       FIG. 5  is an exemplary view of a shape of a FPCB, according to an embodiment of the present invention,  FIG. 6  is an enlarged view schematically illustrating an arrangement structure of a board contact terminal and a pattern circuit with respect to an inner region of a head chip mounting portion of the FPCB of  FIG. 5 , and  FIG. 7  is a view schematically illustrating an arrangement structure of a chip contact terminal of a head chip, according to an embodiment of the present invention. 
     First, the head chip mounting portion  411  is formed on the FPCB  410  such that the head chip  420  is mounted as described above, and the plurality of board contact terminals  412  are formed in the inner region of the head chip mounting portion  411 . Also, a plurality of pattern circuits  413  are formed in the FPCB  410  to be respectively connected to the board contact terminals  412 , wherein the pattern circuits  413  are continuously formed throughout the inner region and an outer region of the head chip mounting portion  411 . 
     In other words, as shown in  FIG. 4 , a separate body connection contact  414  is formed at one side of the FPCB  410  to be connected to the printer body (not shown), and the board contact terminals  412  formed in the inner region of the head chip mounting portion  411  are each connected to the separate body connection contact  414  through the pattern circuits  413 . Here, the pattern circuits  413  are continuously formed throughout the inner region and the outer region of the head chip mounting portion  411  to connect the board contact terminals  412  and the separate body connection contact  414 . 
     Meanwhile, since the board contact terminals  412  are formed in the inner region of the head chip mounting portion  411 , which is a relatively large area compared to the related art, the board contact terminals  412  may be disposed in a shape efficiently using the space. For example, the plurality of board contact terminals  412  may be disposed in lines along a plurality of lines L 1  through L 3  that are parallel to each other. 
     In detail, as shown in  FIG. 6 , the board contact terminals  412  may be disposed in lines along the virtual first line L 1  passing through a center portion of the head chip mounting portion  411 , and the second lines L 2  parallel to the first line L 1  and bilaterally symmetrical to each other based on the first line L 1 . Here, the board contact terminals  412  disposed along the first line L 1  and the board contact terminals  412  disposed along the second lines L 2  may be misaligned in a direction perpendicular to the first line L 1 . 
     In other words, board contact terminals  412 - 2  disposed along the second line L 2  may be disposed in sections between board contact terminals  412 - 1  disposed along the first line, and in this case, the board contact terminals  412 - 2  may be disposed at the centers of the sections between the board contact terminals  412 - 1  disposed along the first line L 1 . In other words, the board contact terminals  412 - 2  disposed along the second line L 2  may be disposed on perpendicular bisectors of the sections between the board contact terminals  412 - 1  disposed along the first line L 1 . 
     According to such an arrangement structure, the two adjacent board contact terminals  412 - 1  disposed along the first line L 1  and one of the board contact terminals  412 - 2  disposed along the second line L 2  form a triangle structure as shown in  FIG. 6 . Here, a triangle formed by three board contact terminals may be an isosceles triangle in which a section between the two adjacent board contact terminals  412 - 1  disposed along the first line L 1  is the base line. In this case, a height h of the isosceles triangle may be lower than a height h′ of an equilateral triangle of which a length of one side is the same as the base line. 
     In other words, an interval h between the first line L 1  and the second line L 2  may be smaller than an interval between the board contact terminals  412 - 1  disposed along the first line L 1  such that the three board contact terminals described above form the isosceles triangle having a lower height than the equilateral triangle, and accordingly, widths of the head chip  420  and the head chip mounting portion  411  may be decreased. 
     Hereinabove, the board contact terminals  412  are disposed in lines along the first and second lines L 1  and  12 , but as shown in  FIG. 6 , a plurality of board contact terminals  412 - 3  may be disposed in lines along the third lines L 3  parallel to the second lines L 2 . Of course, as occasion demands, lines, such as fourth lines and fifth lines, may be continuously added, and the plurality of board contact terminals  412  may be disposed in lines along each of the lines. In this case, the board contact terminals  412 - 3  disposed along the third line L 3  and the board contact terminals  412 - 2  disposed along the second line L 2  may be misaligned in a direction perpendicular to the second line L 2 . 
     Meanwhile, the pattern circuits  413  respectively connected to the board contact terminals  412  may each include a parallel portion  413 - 1  parallel to the first line L 1  in the inner region of the head chip mounting portion  411 , and a slope portion  413 - 2  extending from one end of the parallel portion  413 - 1  in a direction slantly crossing the first line L 1 , wherein one end of the slope portion  413 - 2  may be connected to the board contact terminal  412 . 
     Here, the slope portions  413 - 2  of the pattern circuits  413  respectively connected to the board contact terminals  412  disposed along the first line L 1  may be sequentially alternately formed to be located at a left side and a right side based on the first line L 1 , and accordingly, arrangement space efficiency with respect to the head chip  420  and the head chip mounting portion  411  may be further increased, and the width of the head chip  420  may be minimized. 
     Also, some of the pattern circuits  413  connected to the board contact terminals  412  may be formed such that the slope portions  413 - 2  are formed in a direction crossing the section between the board contact terminals  412 . 
     According to such a structure, the board contact terminals  412  may be disposed to have an enlarged interval in the inner region of the head chip mounting portion  411 , and accordingly, a mounting operation of the head chip  420  may be easily performed without having to perform an operation requiring a high level of precision. 
     Meanwhile,  FIG. 7  illustrates an arrangement structure of the chip contact terminals  422  of the head chip  420 , and the arrangement structure corresponds to that of the board contact terminals  412  described above, and thus details thereof are not provided again. 
     Also, the plurality of ejection nozzles  423  for discharging ink as described above are formed in lines at two edge portions of the head chip  420  in a width direction, and ink penetration preventing line  424  is separately formed in an inner portion of the ejection nozzles  423  as shown in  FIG. 7  such that ink is prevented from penetrating into the inner region of the head chip  420 . The ink penetration preventing line  424  may have a shape of a soldering line, and may cross an entire section of the head chip  420  along a length direction such that the ejection nozzles  423  are separated in a separate division. 
     Here, an ink penetration preventing line  415  is formed in the head chip mounting portion  411  in the same manner as and at a location corresponding to the ink penetration preventing line  424  formed in the head chip  420 . Accordingly, while the head chip  420  is mounted on and combined to the head chip mounting portion  411 , the ink penetration preventing lines  424  and  415  respectively formed in the head chip  420  and the head chip mounting portion  411  are sealed and combined to each other via soldering. 
     According to such a structure, while ink is discharged through the ejection nozzles  423 , the ink may be prevented from penetrating into the inner region of the head chip  420 , in detail, into a region where the chip contact terminals  422  are formed, and accordingly, the chip contact terminals  422  are prevented from being short-circuited by the ink, and thus a print operation may be accurately and stably performed. 
     While this invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The embodiments should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.