1. Field of the Invention
The present invention relates to an inkjet printer, and more particularly to an ink cartridge having an improved structure, which is mounted in an inkjet printer.
2. Related Art
In general, demand for inkjet printers is increasing since an inkjet printer causes less noise, superior resolution, and is less costly for color representing. The inkjet printer performs printing work by attaching bubbles generated by heating an ink to a printing paper through nozzles. To do this work, the inkjet printer comprises a print head unit having a plurality of fine nozzle holes for firing an ink, and an ink cartridge for storing the ink.
FIG. 1A is a sectional side view of a conventional inkjet cartridge of an inkjet printer, and FIG. 1B is a bottom view of the same.
Referring to FIGS. 1A and 1B, the conventional inkjet cartridge of the inkjet printer comprises a housing 10 having an ink chamber 1 for storing an ink, a print head unit 20 connected to one side of the bottom of the housing 10, and a filter 30 for filtering the ink supplied to the print head unit 20.
The housing 10 is mounted on a cartridge (not shown) of the inkjet printer, and thus moves in association with the cartridge. An ink is ejected from the print head unit 20, thereby forming a desired image. At an inner bottom side of the housing 10, a stand pipe chamber 11 is formed for forming an ink path to supply the ink to the print head unit 20.
Between the stand pipe chamber 11 and the ink chamber 1 is disposed a filter 30 to filter the ink stored in the ink chamber 1 and supply the filtered ink to the stand pipe chamber 11.
A receiving part 15 is formed at the bottom of the housing 10 in which the print head unit 20 is received and fixed by an adhesive 19. At the bottom of the receiving part 15, an ink feed hole 17 is formed for forming the ink path. As a result, the ink is supplied to the print head unit 20 passing through the ink chamber 1, the filter 30, the stand pipe chamber 11, and the ink feed hole 17.
FIGS. 2A and 2C show a partially enlarged view of part ‘A’ of FIG. 1B. FIG. 2B is a cross-sectional view along a line II—II of FIG. 2A, and FIG. 2D is a cross-sectional view along a line II′—II′ of FIG. 2C. Referring to FIGS. 2A and 2C, respectively, the ink feed hole 17 is formed either in the center or inclined to one side of the receiving part 15. In order to prevent the adhesive 19 from causing backflow toward the ink feed hole 17 when attaching the print head unit 20 to the receiving part 15, a dam 17a is formed on a circumference of the ink feed hole 17 of the receiving part 15. A thermosetting epoxy for the adhesive 19 is applied in a space between an outer wall 15a of the receiving part 15 and the dam 17a, and a head chip 21 is attached in precise arrangement. The head chip 21 is connected to a flexible circuit board 23 (FIG. 1A), and has a heating element (not shown) and a nozzle hole (not shown).
However, as shown in FIG. 3A, the head chip 21 and a bottom of the receiving part 15 are separated apart by a space S, which causes the head chip 21 to slant when attaching the head chip 21, as shown in FIG. 3B. In addition, the adhesive 19 may flow over the dam 17a to the ink feed hole 17, blocking the nozzle hole or contaminating the ink. Further, the ink drop may be ejected askew rather than vertically with respect to a printing paper. This can result in different arrival distances. Accordingly, an image quality is deteriorated due to the differences of ink dropping positions.
In addition, as shown in FIGS. 4A and 4B, a nozzle unit 21a of the head chip 21, in which the ink flows, is formed as a thin membrane. The print head unit 20 is attached by heat hardening the adhesive 19. At this time, the adhesive 19 is constantly heated more than an hour at high temperature exceeding 100° C. Therefore, the adhesive 19 expands as it is heat-hardened, thereby generating stress that extends to the print head chip 21. Due to the stress, problems usually occur in vulnerably structured print head chips, such as a crack in the membrane, a wire breaking, or breaking of electrically conductive patterns on the chip. Such problems are aggravated when the structure is not symmetrical due to the ink feed hole 17 being inclined to one side of the receiving part 15, or when a sealant is applied broader than the unapplied area, as shown in FIG. 2C. Moreover, the above problems also occur in the multiple color print head unit of a color ink cartridge of FIG. 4B.