Patent Publication Number: US-6213599-B1

Title: Ink-jet cartridge for an ink-jet printing apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to an ink-jet cartridge for an ink-jet printing apparatus, and in particular, to an ink-jet cartridge employing a porous transmission medium to transmit ink. 
     BACKGROUND OF THE INVENTION 
     A conventional ink-jet cartridge is provided with or mounted on an ejecting device. By means of the ejecting device, the ink within the ink-jet cartridge is ejected and printed onto a substrate. However, in order to stably deliver ink with no ink leakage in the ink-jet printing process by the ejecting device, a negative pressure regulating device and an air filling unit are provided within the ink-jet cartridge, for example, as disclosed in U.S. Pat. Nos. 5,409,134 and 5,541,632. This way provides smooth ink delivery without ink leakage, but an additional negative pressure regulating device and an air filling unit are provided. The structures disclosed in these prior art patents are rather complicated and the precision thereof must be quite high. Therefore, its production cost is relatively high. 
     Another conventional ink-jet cartridge is provided with an absorptive material, such as a sponge, to prevent ink leakage 
     However, in this conventional ink-jet cartridge, the entire room within the inkjet cartridge has to be filled with a sponge in order to obtain a good effect of zero ink leakage. Only 60% of the ink within the conventional ink-jet cartridge can be ejected and the remaining ink is kept by the sponge and cannot be ejected. Therefore, it becomes a waste of material. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the present invention to provide an ink-jet cartridge for an ink-jet printing apparatus that achieves the effect of smooth ink delivery and zero ink leakage during printing. 
     Another object of the invention is to provide an ink-jet cartridge for an ink-jet printing apparatus, wherein the inkjet cartridge is simple in structure and easy to assemble. In addition, substantially all the ink within the ink-jet cartridge is ejectable for printing. 
     To achieve the above objects, the ink-jet cartridge for an ink-jet printing apparatus in accordance with the invention comprises a rigid body having an ink reservoir for holding ink within the rigid body and an ink output port at one end of the body so that the ink within the ink reservoir is ejected from the output port; and a porous transmission medium disposed within the ink reservoir of the rigid body, having one end connected to the ink output port so that the ink within the ink reservoir is transmitted to the ink output port through the transmission medium by the capillary action. 
     Thus, in the process of ink-jet printing, when the ink is ejected through the ink output port, the porous transmission medium transmits ink from the ink reservoir to the ink output port. Thereby, the effects of no ink leakage and smooth ink delivery can be obtained. In addition, the ink-jet cartridge is simple in structure and easy to assemble. The ink-jet cartridge occupies only little of the space within the ink reservoir and the major portion of the ink can be ejected for printing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the present invention will become apparent by reference to the following description and accompanying drawings wherein: 
     FIG. 1 is an exploded view of the ink-jet cartridge for an ink-jet printing apparatus in accordance with a preferred embodiment of the invention. 
     FIG. 2 is a view showing a porous transmission medium disposed within the ink reservoir of the ink-jet cartridge of the invention. 
     FIG. 3 is a sectional view taken along the line  3 — 3  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, an ink-jet cartridge for an ink-jet printing apparatus in accordance with the invention comprises a rigid body  10 . An ink reservoir  12  is formed within the rigid body  10  for holding ink. An ink output port  14  is disposed at one end of the rigid body  10  and an ejecting device  16  is disposed at one end of the ink output port  14  so that the ink within the ink reservoir  12  is output through the output port  14 . A cover plate  18  seals the ink reservoir  12 . 
     A mounting plate  20  is disposed between the ink reservoir  12  and the ink output port  14 , and a mounting hole  22  is formed in the mounting plate  20 . 
     A porous transmission medium  24  is disposed within the ink reservoir  12  of the rigid body  10  having one or more bends. In accordance with a preferred embodiment of the invention, the porous transmission medium  24  is an n-shaped structure, including two transmission ends wherein one is an input end  26  and the other is an output end  28 . The output end  28  is adjacent to the ink output port  14  and is mounted in the mounting hole  22  in the mounting plate  20 . The porous transmission medium  24  is a sponge, a non-woven material, or the like, and the ink within the ink reservoir  12  is transmitted into the ink output port  14  via the input end  26  and the output end  28  by the capillary action. An impermeable sheath  30  is formed between the input end  26  and the output end  28  so that the ink can only be transmitted into the ink output port  14  from the input end  26  to the output end  28  by the capillary action. The porous transmission medium  24  and the ink do not generate chemical reaction that may incur the corrosion or damage of the porous transmission medium  24 . 
     Referring to FIG. 2, the mounting plate  20  is first mounted in between the ink reservoir  12  and the ink output port  14 , and the output end  28  of the porous transmission medium  24  is then disposed in the mounting hole  22  of the mounting plate  20 . The cover plate  18  seals the ink reservoir  12  of the rigid body  10  to form a closed space so that no ink leakage occurs when ink is injected into the ink reservoir  12 . 
     Referring to FIGS. 2 and 3, in the process of ink-jet printing, the ink within the ink output port  14  is ejected by the ejecting device  16  and the pressure within the ink output port  14  decreases. At this time, the ink in the ink reservoir  12  is transmitted from the input end  26  to the output end  28  through the porous transmission medium  24  by the capillary action in order to supply ink into the ink output port  14 . Thereby, the ink-jet cartridge achieves the effects of no ink leakage and smooth ink delivery. In addition, the inkjet cartridge is simple in structure and easy to assemble. The porous transmission medium  24  occupies only a little of the space within the ink reservoir and the major portion of the ink can be ejected for printing. This avoids the disadvantage of the ink incapable of being fully utilized of a conventional ink reservoir that is entirely occupied by a sponge. 
     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.