Patent Publication Number: US-6698872-B2

Title: Ink cartridge for preventing ink from spilling

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an inkjet printer, and more particularly, to an ink cartridge which can prevent ink from spilling. 
     2. Description of the Prior Art 
     A typical inkjet printer has an ink cartridge for supplying ink. For a color inkjet printer, the ink cartridge commonly has three ink chambers for storing red, green and blue ink. When printing a document, the ink stored in different ink chambers will be ejected from the ink cartridge onto the document to form various colors on the document. Moreover, the ink cartridge has an opening above each of the ink chambers so that air inside the ink chamber can be interchanged with air outside the ink chamber. 
     In an ink chamber, a complex pressure balancing system is required for balancing the fluid pressure since ink within the ink chamber is consumed continually. One way to store the ink includes filling a porous material in the ink chamber and balancing the pressure by using the opening above the ink chamber. U.S. Pat. No. 4,771,295 discloses such an ink chamber. However, the ink chamber has a major drawback. The porous material tends to diverse ink all over the porous material due to capillary action. Therefore, when the ink cartridge is vibrated, the ink absorbed by top portion of the porous material is likely spilled out of the ink cartridge via the opening of the ink chamber, not only spotting the document during a printing process but also mixing up the ink in other ink chambers. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an ink cartridge of an inkjet printer to solve the aforementioned problems. 
     In accordance with the claimed invention, the ink cartridge includes a housing, an output channel, a porous material and an adhesive layer. The housing has a vertical ink chamber for storing ink and an opening disposed on a top side of the ink chamber for interchanging air inside the ink chamber with air outside the ink chamber. The output channel is connected with a bottom aide of the ink chamber for supplying ink from the ink chamber. The porous material is filled in the ink chamber for absorbing ink within the ink chamber. The adhesive layer is formed at a top end of the porous material for forming a sealed surface on the top end of the porous material. 
     It is an advantage of the present invention that the ink cartridge has an adhesive layer formed on the top end of the porous material. This prevents spotting of a document during a printing process and mixing up ink in other ink chambers. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an ink cartridge according to the present invention. 
     FIG. 2 is a cross-sectional view along line  2 — 2  of the ink cartridge in FIG.  1 . 
     FIG. 3 shows a cross-sectional view of another ink cartridge. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to FIG. 1 of a perspective view of an ink cartridge  10  of the present invention. The ink cartridge  10  comprises a housing  14  having three vertical ink chambers  18  for storing ink and an opening  16  disposed on a top side  12  of each of the three ink chambers  18  for interchanging air inside the ink chambers  18  with air outside the ink chambers  18 . The ink cartridge also comprises three output channels  20  each connected with a bottom side  22  of a corresponding Ink chamber  18  for supplying ink from the ink chamber  18 . 
     Please refer to FIG. 2 of a cross-sectional view along line  2 — 2  of the ink cartridge  10  in FIG.  1 . The ink cartridge  10  further comprises a porous material  24  filled in each of the ink chambers  18  for absorbing ink within the ink chamber  18 , and an adhesive layer  26  formed on a top end  28  of the porous material  24  for forming a sealed surface on the top end  28  of the porous material  24 . 
     The adhesive layer  26  can be formed either by spraying an adhesive substance on the top end  28  of the porous material  24  or by fusing the top end  28  of the porous material  24 . The adhesive can also be scotch tape or other means as long as the top end  28  of the porous material  24  can be sealed. After the adhesive layer  26  is formed, a gap  30  is formed around the adhesive layer  26  so that air within the ink chamber  18  can interchange with air outside of the ink chamber  18  to balance the fluid pressure in the ink chamber  18  with outside environment. 
     Please refer to FIG.  3 . FIG. 3 shows a cross-sectional view of another ink cartridge  40 . The ink cartridge  40  differs from the ink cartridge  10  in that the ink cartridge  40  further comprises a filling material  42  positioned or formed above each adhesive layer  26  for preventing the ink absorbed by the porous material  24  from spilling out of the corresponding ink chamber  18 . As can be seen from FIG. 2, when the ink cartridge  10  experiences an intense vibration or is upside down, the ink absorbed by the porous material  24  may leak through the gap  30  around the adhesive layer  26 . Therefore, the filling material  42  in FIG. 3 can absorb the leakage to prevent ink from spilling out of the ink chamber  18  through the opening  16 . 
     The filling material  42  can be porous to absorb ink spilled out of the porous material. Furthermore, both the porous material  24  and the filling material  42  can be sponge. However, the capillary action of the filling material  42  is less than that of the porous material  24 . Thus during normal operations, the ink absorbed by the filling material  42  tends to flow downward to the porous material  24  through the gap  30  leaving little ink in the filling material  42 . 
     In FIG. 3, each adhesive layer  26  can be formed by spraying a sticky substance such as glue only onto the top end  28  of the porous material  24  or onto both a bottom end  44  of the filling material  42  and the top end  28  of the porous material  24  to join the filling material  42  together with the porous material  24 . The adhesive layer  26  can also be formed by fusing only the top end  28  of the porous material  24  or both the top end  28  of the porous material  24  and the bottom end  44  of the filling material  42 . The adhesive layer  26  can further be single-sided tape stuck only onto the top end  28  of the porous material  24  or double-sided tape stuck to both the top end  28  of the porous material  24  and the bottom end  44  of the filling material  42 . 
     Compared with prior art, the ink cartridge  10 ,  40  has an adhesive layer  26  formed on the top end  28  of the porous material  24 . The adhesive layer  26  forms a sealed surface on the top end  28  of the porous material  24  so that ink absorbed by the porous materials  24  cannot spill out of the ink chambers  18  easily. This prevents spotting of a document during a printing process and mixing up ink in other ink chambers  18 . 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.