Abstract:
A method for assembling an ink cartridge, the method includes the steps of providing a reservoir body having a fluid discharge port including a rim; inserting a wick in the discharge port; providing an opening that is bounded by the rim; inserting a capillary media into the reservoir body and the capillary media contacts a portion on the wick; affixing a lid to the reservoir body and the lid includes a hole and an air vent; injecting ink into the capillary through the hole in the lid; wherein a vent path is formed extending from the opening, along at least a side of the capillary media and to the air vent in the lid.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a Divisional of prior U.S. patent application Ser. No. 11/679,925 filed Feb. 28, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention pertain to an ink jet ink cartridge with porous capillary media to provide pressure regulation and a wick to supply ink from the capillary media into a printhead. According to embodiments of the present invention, an opening is provided in the wick in order to form a vent path. 
       BACKGROUND OF THE INVENTION 
       [0003]    Fluid-ejection printing devices, such as ink jet printers, commonly have at least one ink cartridge and a printhead chassis that supports the ink cartridge. The ink cartridge may contain one or more reservoirs that provide ink or some other fluid to a printhead. If the ink cartridge has more than one reservoir, each such reservoir often retains fluid of a different color for multi-color printing. On the other hand, if the ink cartridge has only a single reservoir, typically such reservoir is used to retain black ink for black-and-white printing. 
         [0004]    The printhead is formed of a printhead die, which typically is connected directly or indirectly to the chassis. In order to form an image, the printhead die, along with the chassis and the ink cartridge, generally are moved in a lateral direction across a width of a substrate, such as paper, as fluid is ejected from the printhead. After the printhead forms a row-portion of the image along the width of the substrate, the substrate is advanced in a direction perpendicular to the lateral direction along a length of the substrate, so that the printhead can form a subsequent row-portion of the image. This process of advancing the substrate for each row-portion is repeated until a next substrate is needed or the image is completed. 
         [0005]    For proper operation of the printhead and ink cartridge assembly, it is necessary to regulate the pressure within the ink cartridge. Pressure changes may occur during shipping or storage due to air pressure changes or temperature changes, for example. Pressure changes may occur during printing due to depletion of ink within the ink cartridge as ink is gradually used up, or due to surges that occur during acceleration and deceleration at the end of a row of printing. If the fluid pressure is too great, ink may be caused to dribble out of fluid-ejecting nozzles of the printhead die, or too much ink may be ejected. If the fluid pressure is too small, the printhead may experience ink starvation, resulting in too little ink being ejected so that white streaks are apparent in the printed image. 
         [0006]    One method of providing pressure regulation is to have a porous capillary media within the ink reservoir of the ink cartridge. The capillary media is typically a rectangular shaped piece of foam or felt. Capillary forces tend to keep the ink at a slightly negative pressure, so that ink does not run out of the printhead nozzles, which are typically positioned at a lower height (i.e., closer to the substrate) than the ink reservoir. The ink cartridge contains a fluid discharge port for ink to travel from the ink reservoir to the printhead chassis through a pipe which serves as the fluid reception port on the chassis. In order to facilitate a steady flow of ink as needed during printing, a common configuration is to provide a wick (also known as a scavenger member, or an ink delivery member) at the fluid discharge port. The wick is in contact with the capillary media and has different capillary properties than the capillary media. When the ink cartridge is loaded into the printhead chassis, typically the wick is forced into contact with a filter member at the mouth of the fluid reception port. Once the printhead is primed so that fluid fills the various ink passageways between the capillary media and the nozzles on the printhead die, capillary forces take care of supplying ink as needed for printing. 
         [0007]    When an ink reservoir in the ink cartridge runs out of ink, a user is charged with the responsibility of removing the empty ink cartridge from the chassis and replacing it with a full ink cartridge. The task of replacing an ink cartridge must be simple and clean so that ink is not incidentally discharged during such a replacement process. If ink is discharged during such a replacement process, ink could stain the user&#39;s hands or clothes, and it also could drip into areas of the printer where it might cause damage. 
         [0008]    For example, conventional ink cartridges include a shipping cap that seals the fluid discharge port(s). The shipping cap helps to prevent ink evaporation during long-term storage, as well as ink spillage due to air pressure changes. The ink cartridge is generally also provided with a vent path to help relieve pressure differences during shipping, storage, and printing. However, when these shipping caps are removed by a user when installing the ink cartridge into a printer, a transient reduction in pressure at the fluid discharge port opening is caused. This transient reduction in pressure can force ink out of the fluid discharge port during removal of the cap and can cause staining or damage. 
         [0009]    Accordingly, a need in the art exists for a cap removal solution that allows a user to simply and cleanly remove the shipping cap from a new ink cartridge prior to insertion of the ink cartridge into the printhead chassis. 
       SUMMARY 
       [0010]    The above-described problems are addressed and a technical solution is achieved in the art by a printing device ink cartridge, according to various embodiments of the present invention. According to an embodiment, an ink cartridge includes a reservoir configured to retain ink, a body retaining the reservoir, a port in the body, and a wick located in the port. The port is configured to release the ink from the reservoir. According to an embodiment of the present invention, the body includes a first opening, and the wick includes a second opening, such that the first opening and the second opening are communicatively connected to form a vent path or a portion of a vent path. Such a vent path mitigates the transient reduction in pressure caused by a removal of a shipping cap, thereby reducing the likelihood that ink spillage will occur during such removal. 
         [0011]    According to various embodiments of the present invention, the first opening may be on a surface of the body configured to face up when the ink cartridge is in an orientation in which it is configured to operate. The surface may include a grooved path from the first opening to an edge of the surface, the grooved path forming a portion of the vent path. Also, the second opening may be a notch. Such a notch may have a rounded or substantially rounded interior surface. The second opening may be in a region of the wick that is not configured to contact a fluid reception port of a chassis configured to retain the ink cartridge. The wick may further include a third opening on an opposite side from the second opening. The wick may be symmetrical or substantially symmetrical. 
         [0012]    According to various embodiments of the present invention, the ink cartridge may include a capillary media within the reservoir, the capillary media contacting the wick. A space may exist between a surface of the capillary media and an interior surface of the body, the space forming a portion of the vent path. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention will be more readily understood from the detailed description of exemplary embodiments presented below considered in conjunction with the attached drawings, of which: 
           [0014]      FIG. 1  illustrates a printhead chassis for retaining one or more ink cartridges; 
           [0015]      FIG. 2  shows an isometric view of a multi-reservoir ink cartridge; 
           [0016]      FIG. 3  shows an exploded view of a multi-reservoir ink cartridge, according to an embodiment of the present invention; 
           [0017]      FIG. 4  shows a bottom view of a multi-reservoir ink cartridge, according to an embodiment of the present invention; 
           [0018]      FIG. 5  shows a side view of an ink cartridge with a shipping seal; 
           [0019]      FIG. 6  shows a side view of an ink cartridge, according to an embodiment of the present invention; 
           [0020]      FIG. 7A  shows a top view of a prior art wick; and 
           [0021]      FIGS. 7B through 7D  show top views of wicks, according to embodiments of the present invention. 
       
    
    
       [0022]    It is to be understood that the attached drawings are for purposes of illustrating the concepts of the invention and may not be to scale. 
       DETAILED DESCRIPTION 
       [0023]    Embodiments of the present invention provide one or more openings or notches in a wick for an ink cartridge, such that at least one opening in the wick is communicatively connected to an opening in the body of the ink cartridge in order to provide a vent path to the opening of the fluid discharge port of the ink cartridge. 
         [0024]      FIG. 1  illustrates a printhead chassis  10 . The printhead chassis has a region  12  for a multi-reservoir ink cartridge, and also a region  14  for a single-reservoir ink cartridge. Regions  12  and  14  are separated by one or more partitions  16  which also serve as guides for inserting the ink cartridges into the printhead chassis. In region  12 , several fluid reception ports  18  are shown which make connection with the corresponding fluid discharge ports of a multi-reservoir ink cartridge, when the ink cartridge is inserted. Region  14  also has a single fluid reception port (hidden by partition  16 ) corresponding to the fluid discharge port of a single-reservoir ink cartridge. Not shown in the view of  FIG. 1  is the printhead die and its nozzles. Typically, the printhead die would be located underneath the printhead chassis, in a region below the fluid reception ports  18 . 
         [0025]      FIG. 2  shows an isometric view of a multi-reservoir ink cartridge  20  which may be inserted into region  12  of printhead chassis  10 . The particular ink cartridge  20  shown in  FIG. 2  has five reservoirs within reservoir body  22 , each reservoir of which leads to a fluid discharge port  24 . The five reservoirs serve as reservoirs intended to hold five fluid sources. The five sources may be, for example, cyan ink, magenta ink, yellow ink, photo black ink, and a protective fluid. Alternatively, they may be cyan ink, light cyan ink, magenta ink, light magenta ink, and yellow ink; or they may be a different combination of fluids. 
         [0026]    Ink cartridge  20  is shown as having a lid  30  in the example shown in  FIG. 2 . Lid  30  is affixed to reservoir body  22 . Together, lid  30  and reservoir body  22  make up the ink cartridge body. Typically the lid  30  and the reservoir body  22  are each formed by injection molding. The top surface of lid  30  is formed with grooves in it, as well as one or more holes through the lid, corresponding to the location of each reservoir in the reservoir body. A vent hole (not shown) allows air to pass from the interior of the reservoir to the top of the lid. Each vent hole is intersected by one of the grooved pathways  32  in the lid  30 . The grooved pathway  32  may take a circuitous path on the top of the lid  30 , but emerges from one edge of the lid. A label  36  is adhered to the top of the lid  30 , forming a roof for the grooved pathways  32 . Where the grooved pathways  32  emerge from the edge of the lid  30 , they form lid vent openings  34  (one lid vent opening per ink reservoir). Since the lid  30  is affixed to reservoir body  22 , the lid vent openings  34  each form an opening in the assembled ink cartridge body. Because the lid faces up when the ink cartridge is installed in the printhead chassis in the printer, the lid vent opening  34  is on a surface of the ink cartridge body that faces up when the ink cartridge is in a position in which it is configured to operate. 
         [0027]      FIG. 3  shows an exploded view of multi-reservoir ink cartridge  20  as well as shipping cap seal assembly  50 , according to an embodiment of the present invention. Assembly of ink cartridge  20  proceeds substantially as follows: Wicks  44  are inserted into reservoir body  22 , with one wick per reservoir, each wick  44  being located at a corresponding fluid discharge port  24 . Then capillary media  42  is inserted into reservoir body  22 , with one piece of capillary media  42  per reservoir, each capillary media being in contact at its bottom side  43  with the top side of a corresponding wick  44 . Then lid  30  is affixed to reservoir body  22  by ultrasonic welding or other means of adhering the lid to the reservoir body. Then ink is injected into the capillary media by inserting one or more needles through holes in lid locations corresponding to each reservoir. Then one or more labels  36  are affixed to the top surface of the lid  30 . The lower label  36  has a primary function of sealing the top of the grooved pathway  32  in the top surface of the lid, while the upper label  36  has a primary function of providing information about the ink cartridge. 
         [0028]      FIG. 4  shows a bottom view of multi-reservoir ink cartridge  20  with the bottom surface  45  of each wick  44  visible within each port  24 , according to an embodiment of the present invention. Note that the bottom surface  45  of wick  44  is recessed somewhat relative to the outer rim  26  of port  24 . Note also wick opening  46  provided in each wick  44 . Wick opening  46  is also shown in  FIG. 3  and will be discussed below. 
         [0029]    When the ink or other fluids have been injected into the respective capillary media  42  in each reservoir, the ink penetrates through the capillary media and also saturates the corresponding wick  44  in the corresponding port  24 . Before the ink cartridge  20  is ready to be shipped to the customer, the ports are sealed in order to prevent leakage or excessive evaporation of volatile ink components. Many different styles of seals are possible to be used. For example, a film may be affixed to the outer rim of each port. For this type of seal, the customer may pull a tab at an end of the film and thereby pull the seal away from each port. A second alternative is a twist-off seal, although this type of seal is more compatible with a cartridge having only a single port. With a row of ports  24  as in multi-reservoir ink cartridge  20 , the amount of torque to twist off seals from five adjacent reservoirs would be excessively difficult for the user to apply. A third alternative is a seal of the type provided by shipping cap seal assembly  50  shown in  FIG. 3 . Shipping cap seal assembly  50  includes a compliant seal member  52  which is held in place at the ports  24  by cap seal retainer  54 . Compliant seal member  52  is typically is formed using an elastomeric material such as EPDM rubber. Seal retainer  54  is typically formed by injection molding. The sealing member may protrude somewhat into the port, but typically there is still an air space between the bottom surface  45  of wick  44  and the sealing member. 
         [0030]      FIG. 5  shows a cutaway side view of ink cartridge  20  with shipping cap seal assembly  50  installed in order to prepare it for shipping, according to an embodiment of the present invention. Bottom side  43  of capillary media  42  is shown in contact with the top surface of wick  44 . Sealing member  52  is shown pressed against port  24  and held in place by seal retainer  54 . In order to remove seal retainer  54 , the user presses on seal retainer lever  56  in a downward direction denoted by arrow  60 . As a result, the sealing member  52  is pulled away from outer rim  26  of fluid discharge port  24  in a direction denoted by arrow  62 . 
         [0031]    It is advantageous to unseal a sealing member by moving it away from one end of the outer rim  26  first. However, as the sealing member  52  is pulled away in an angular direction, because of the downward component of sealing member&#39;s motion, a momentary air pressure drop is produced in the air space between the bottom surface  45  of wick  44  and the sealing member. This is because the air volume of the air space, which has been at a first equilibrium volume, is increased as the sealing member is pulled away. Since pressure is inversely proportional to volume, as the air volume of the air space increases, its pressure decreases. Since the wick is saturated with ink, unless there is an opening  46  in wick  44 , such that opening  46  is part of a vent path to atmosphere, the reduced pressure in the air space (between the bottom  45  of wick  44  and the sealing member  52 ) will result in ink being forced out of ink cartridge  20  through fluid discharge port  24 . If the seal is pulled away suddenly, droplets of ink may splatter out and stain the hands of the user or get onto the printer or other objects. This is true whether the seal is a compliant seal such as sealing member  52 , or whether the seal is an adhesively affixed film. Somewhat less susceptible to such volume and pressure changes are the types of seals which may be removed in a twisting motion, since the volume change is very small as the seal is broken. However, as mentioned above, twist-off type seals are not very compatible with multi-reservoir ink cartridges having a row of adjacent ports  24 . 
         [0032]      FIG. 6  shows a cutaway side view of an ink cartridge  20  including a wick  44  with a wick opening  46  that forms a part of a vent path  48  between the bottom of wick  44  and atmospheric pressure, according to an embodiment of the present invention.  FIG. 6  is similar to  FIG. 5 , although the sealing cap assembly  50  has been removed for clarity. Also, the wick opening  46  and the vent path  48  between the capillary media  42  and an interior surface of reservoir body  22  are denoted. Vent path  48  extends from lid vent opening  34 , along the side, bottom and top of capillary media  42  (the top of capillary media being spaced apart from the lid surface by projections as seen in  FIGS. 3 and 5 ), and from there to wick opening  46  which passes through wick  44 . With such a wick opening  46  that forms a portion of a vent path from the bottom surface  45  of wick  44  to atmosphere via lid vent opening  34 , removing a sealing member even in a fashion that tends to abruptly increase the air volume in the air space between the bottom of the wick and the sealing member, does not result in a substantial decrease in pressure, because the pressure can be instantly equilibrated with atmospheric pressure. As a result, ink splatters can be substantially eliminated. 
         [0033]      FIG. 7  shows top views of several wick configurations.  FIG. 7A  shows the prior art wick having no wick opening, while  FIGS. 7  B-D show embodiments of the present invention.  FIG. 7B  shows the opening  46  in the form of curved opening, while  FIG. 7C  shows the opening  46  in the form of a V-shaped notch. Generically we refer to the openings  46  of both  FIGS. 7B and 7C  as notches. These notches extend from the top surface (shown in  FIG. 7  B-D) along the side of wick  44  and to bottom surface  45 . Also shown in  FIG. 7  B-D is the region  49  of the wick  44  that is configured to contact fluid reception port  18  of printhead chassis  10 . Note from  FIGS. 1 and 4  that fluid reception port  18  is round, while fluid discharge port  24  (and consequently wick  44 ) is oval-shaped. Wick opening  46  is provided along an edge of the wick and is not located in the region  49  configured to contact the fluid reception port  18 . Note also from  FIG. 6  that the location of the wick opening  46  can be important. In the example of  FIG. 6 , a vent path  48  that leads to lid vent opening  34  (via grooved pathway  32 ) is provided if wick vent opening  46  is located at the left side of wick  44  when the ink cartridge  20  is oriented in the configuration shown in  FIG. 6 . Thus, wick orientations similar to  FIGS. 7B and 7C  would be acceptable, but a wick oriented 180 degrees from those orientations would not provide a continuous vent path. Because assembly of the wicks  44  into their corresponding ports  24  in a single allowable orientation may introduce manufacturing complexities, a wick configuration as shown in  FIG. 7D  may be advantageous in some applications. In the configuration of  FIG. 7D , wick openings  46  are symmetrically disposed at both ends of wick  44 . In such a configuration it does not matter whether the wick is rotated or flipped over. A wick opening  46  will still be in an acceptable orientation to provide a vent path. 
         [0034]    Although the examples above discuss embodiments in a multi-reservoir cartridge  20 , it is to be understood that the same advantages apply to a single reservoir cartridge. 
         [0035]    It is to be understood that the exemplary embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by one skilled in the art without departing from the scope of the invention. It is therefore intended that all such variations be included within the scope of the following claims and their equivalents. 
       PARTS LIST 
       [0000]    
       
           10  Printhead chassis 
           12  Region for multi-reservoir cartridge 
           14  Region for single reservoir cartridge 
           16  Partition 
           18  Fluid reception port 
           20  Multi-reservoir ink cartridge 
           22  Reservoir body 
           24  Fluid discharge port 
           26  Outer rim of fluid discharge port 
           30  Lid 
           32  Grooved pathway 
           34  Lid vent opening 
           36  Label 
           42  Capillary media 
           43  Bottom side of capillary media 
           44  Wick 
           45  Bottom surface of wick 
           46  Wick opening 
           48  Vent path 
           49  Wick region for contact with fluid reception port 
           50  Shipping cap seal assembly 
           52  Seal member 
           54  Cap seal retainer 
           56  Seal retainer lever 
           60  Direction arrow 
           62  Direction arrow