Abstract:
Disclosed herein is an ink cartridge refill system for inkjet printers and a method of refilling ink cartridges using the system. The refill system includes a vacuum pump to supply ink from an ink tank into a cylinder and to forcibly draw ink from an ink cartridge, as well as an air compression pump to generate a compression force to inject ink from the cylinder into the ink cartridge through the nozzle of the cartridge. The cylinder is connected at the inlet end thereof to both the air compression pump and the vacuum pump, and is connected at the outlet end to both the ink tank and the ink cartridge. Both a compression pump line and a first vacuum pump line which pass through the cylinder are connected to the nozzle of the cartridge through an ink supply hose. The vacuum pump includes a second vacuum pump line directly connected to the ink cartridge, as is the first vacuum pump line passing through the cylinder. Both the ink supply hose and the second vacuum pump line are connected to the nozzle of the cartridge through a connection unit. The refill system can regulate the inner pressure of a refilled cartridge by removing predetermined small amounts of air and ink from the refilled cartridge, and can completely remove waste ink from the cartridge at the initial stage of a cartridge refill process when necessary.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to an ink cartridge refill system for inkjet printers and method of refilling ink cartridges using the system. 
   2. Description of the Related Art 
   Most users of inkjet printers prefer to refill and reuse ink cartridges rather than use new ink cartridges because the new ink cartridges are expensive. In an effort to satisfy the above-mentioned preference of the users of inkjet printers, some ink cartridge manufacturers have proposed and marketed ink cartridges that are provided with refill nozzles to allow users to refill ink cartridges through the refill nozzles. 
   Korean Patent Laid-open Publication No. 10-2003-69596, which was published on Aug. 27, 2003, discloses a conventional ink cartridge refill system that is configured as a refill system to be used by someone in the business of refilling customers&#39; ink cartridges. The above-mentioned refill system is constructed such that an ink cartridge is loaded in a cartridge loading unit and is refilled with ink simply by manipulating a control switch of the cartridge loading unit. 
   Herein below, the conventional ink cartridge refill system  100 , disclosed in the above-mentioned Korean Patent Laid-open Publication Gazette, will be described with reference to  FIGS. 1 through 4 . 
   As shown in  FIG. 1 , the conventional ink cartridge refill system  100  includes a plurality of cartridge loading units  110  in each of which an ink cartridge (not shown) to be refilled with ink is loaded. The refill system  100  also includes a plurality of ink reservoirs  120  to inject ink, temporarily contained therein, into ink cartridges loaded in the cartridge loading unit  110  through a plurality of ink injection hoses  101 , and an ink tank  140  which stores ink therein and supplies ink to the ink reservoirs  120  through a plurality of ink supply hoses  102 . Furthermore, a plurality of pressure cylinders  130  is connected to an air compression pump  150  through a plurality of air hoses. 
   The above-mentioned refill system  100  is operated as follows. When a control switch  104  is turned on after completely loading an ink cartridge into a cartridge loading unit  110 , pressurized air from the air compression pump  150  is introduced into the pressure cylinders  130  associated with the cartridge loading unit  110 , so that air pressure acts on the pistons (not shown) in the cylinders  130 . Thus, the interior of the ink reservoir  120  is compressed, so that ink from the ink reservoir  120  is injected into the loaded ink cartridge. When the ink cartridge has been completely refilled with ink, the pressure in the cylinders  130  is reduced, causing the pressure in the ink reservoir  120  to be reduced. As the pressure in the ink reservoir  120  becomes reduced as described above, ink is newly supplied from the ink tank  140  into the ink reservoir  120 . 
   In the refill system  100  shown in  FIG. 1 , three ink supply hoses  102  and three ink injection hoses  101  are provided to supply or inject different colors of ink, which are cyan ink, magenta ink and yellow ink. A one-way valve  101   a ,  102   a  is installed in each of the three ink injection hoses  101  and three ink supply hoses  102 , thus preventing ink from flowing in a reverse direction while the ink flows from the ink reservoir  120  into the loaded ink cartridge or from the ink tank  140  into the ink reservoir  120 . Each of the chambers of the ink tank  140  and the ink reservoir  120  is partitioned into three storage chambers, thereby separately containing the three different colors of ink therein. Furthermore, the three pressure cylinders  130  are provided to respectively communicate with the three storage chambers of the ink reservoir  120 . 
   As shown in  FIGS. 2 and 3 , each of the cartridge loading units  110  of the refill system  100  comprises a body  111  in which an ink cartridge  1  is seated, an ink injection part  112  which comes into close contact with the nozzles  2  of the cartridge  1 , and a cartridge holding part  120  which is placed at the opposite end from the nozzles  2  of the cartridge  1 . The cartridge holding part  120  is configured such that, when a handle  121  is rotated upwards or downwards around a joint, the rotating motion of the handle  121  is converted into rectilinear motion of a sliding bar  122  by a link  123 , so that the sliding bar  122  linearly moves forwards or rearwards. A cushion member  124  is mounted to the front end of the sliding bar  122 , thus protecting the ink cartridge  1  from being impacted when the cartridge  1  is loaded into the cartridge loading unit  110 . 
   The ink injection part  112 , which comes into close contact with the nozzles  2  of the ink cartridge  1 , is provided with a plurality of ink injection holes  113  that respectively correspond to the nozzles  2  of the cartridge  1 . The ink injection holes  113  are connected to the ink injection hoses  101  by means of a plurality of connectors  115 . As shown in  FIG. 4 , three different colors of ink, which are cyan ink, magenta ink and yellow ink, respectively supplied through the three ink injection holes  113 , are injected into the ink cartridge  1  via the three nozzles  2 . 
   Although the above-mentioned ink cartridge refill system is advantageous in that the system refills an ink cartridge in response to simple operation of the control switch after an ink cartridge has been loaded into a cartridge loading unit, the refill system is problematic as follows. The problems experienced in the conventional ink cartridge refill system will be described herein below with reference to  FIGS. 1 through 4 . 
   When ink is injected into an ink cartridge through the nozzles of the cartridge using air pressure in the manner disclosed for the above-mentioned refill system  100 , the inner pressure of the cartridge  1  has increased to a level higher than atmospheric pressure at the time that the ink cartridge refill process has been completed, due to both pressurized air and ink having been injected into the cartridge  1 . Thus, if the ink cartridge  1  which has been completely refilled with ink is directly detached from the cartridge loading unit  110 , the ink may be ejected by the pressure of the cartridge  1  to the atmosphere through the nozzles  2 . The ejected ink messes up both the nozzles  2  and the cartridge loading unit  110 . 
   Furthermore, the ink remaining in the gap between the nozzles  2  and the ink injection part  112  flows down and contaminates the cartridge loading unit  110 . 
   The ink cartridges for inkjet printers have been typically classified into two types: sponge type and pack type. Particularly, the pressure of the pack-type ink cartridges must be regulated after refilling the cartridges. The regulation of the pressure of the pack-type cartridges is made necessary by the fact that an excessive amount of ink may be discharged from the cartridge and deteriorate printing quality when the cartridge is first used, as well as the fact that the ink may be ejected under pressure at the time that the refilled cartridge is detached from the cartridge loading unit  110 . 
   In an effort to solve the above-mentioned problems, it is necessary to expel predetermined small amounts of air and ink from a refilled cartridge and to regulate the inner pressure of the cartridge when the ink cartridge refill process has been completed. However, the above-mentioned conventional ink cartridge refill system is not configured to regulate the inner pressure of ink cartridges after refilling the cartridges. 
   Furthermore, the above-mentioned ink cartridge refill system is not compatible with a variety of ink cartridges having different sizes and different capacities. Described in detail, when it is desired to refill an ink cartridge having a size and capacity different from those of a previously refilled cartridge, a user must change the length of the sliding bar  122  before turning on the control switch, so that the sliding bar  122  supports the cartridge with an appropriate biasing force. Furthermore, to inject an appropriate amount of ink into an ink cartridge loaded in the cartridge loading unit, it is necessary to adjust the strokes of the pistons in the pressure cylinders  130  by adjusting a plurality of ink supply control units  131  provided on the cylinders  130 . 
   Because the above-mentioned conventional refill system  100  is provided only with a one-way valve  101   a  in each of the ink injection hoses  101  in an effort to prevent ink from flowing in a reverse direction toward the ink reservoir  120 , small amounts of ink inevitably remain in the ink injection holes  113  after an ink cartridge has been completely refilled with ink by the refill system. Thus, when the cartridge loading unit  110  having the ink injection holes  113  in which ink remains is not used for a lengthy period of time, the quality of ink remaining in the ink injection holes  113  is reduced. When the ink having the reduced quality is injected into a cartridge during a refill process, the printing quality is reduced and, furthermore, the nozzles of the cartridge may become blocked. 
   Typically, ink is not completely used but some ink may remain in an ink cartridge  1 , so that it is sometime required to completely empty the cartridge  1  prior to refilling the cartridge  1 . However, the conventional ink cartridge refill system  100  is configured such that the system  100  merely injects ink into cartridges  1  and does not automatically empty the cartridges. Thus, the user of the refill system  100  must manually empty the cartridges  1  prior to refilling the cartridges  1 , so that it is inconvenient for the user to use the system  100 . 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an ink cartridge refill system which removes predetermined small amounts of air and ink from a refilled cartridge and regulates the inner pressure of the cartridge after an ink cartridge refill process has been completed, and which can completely remove remaining ink from the cartridge at the initial stage of the ink cartridge refill process when necessary. 
   Another object of the present invention is to provide an ink cartridge refill system which removes remaining ink from both the ink injection hole and the gap defined between the nozzle of the ink cartridge and the ink injection hole after the ink cartridge refill process has been completed. 
   A further object of the present invention is to provide an ink cartridge refill system which can be operated simply by manipulating a control button. 
   Yet another object of the present invention is to provide an ink cartridge refill system which is configured such that a user can manage the ink cartridge refill process while viewing the entire process of refilling the ink cartridge. 
   Still another object of the present invention is to provide a method of refilling ink cartridges using the refill system. 
   In order to accomplish the above objects, the present invention provides an ink cartridge refill system which includes a vacuum pump to supply ink from an ink tank into a cylinder and to forcibly draw ink from an ink cartridge, as well as an air compression pump to generate air pressure to forcibly inject ink stored in the cylinder into the ink cartridge. In the refill system, ink is injected into the ink cartridge through the nozzle of the cartridge. 
   Furthermore, the cylinder is connected at the inlet end thereof to both the air compression pump and the vacuum pump, and is connected at the outlet end thereof to both the ink tank and the ink cartridge. In the refill system, both a compression pump line and a first vacuum pump line which pass through the cylinder are connected to the nozzle of the ink cartridge through an ink supply hose. 
   Furthermore, the vacuum pump includes a second vacuum pump line which is directly connected to the ink cartridge, as is the first vacuum pump line which passes through the cylinder. Both the ink supply hose and the second vacuum pump line are connected to the nozzle of the ink cartridge through a connection unit. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a view schematically showing the construction of a conventional ink cartridge refill system; 
       FIGS. 2 and 3  are side views of a cartridge loading unit constituting the conventional cartridge refill system shown in  FIG. 1 , in which  FIG. 2  shows a first state wherein an ink cartridge has not been completely loaded in the cartridge loading unit, and  FIG. 3  shows a second state wherein the cartridge has been completely loaded in the cartridge loading unit; 
       FIG. 4  is an enlarged view of the encircled portion shown in  FIG. 3 ; 
       FIG. 5  is a view schematically showing the construction of an ink cartridge refill system, according to an embodiment of the present invention; 
       FIG. 6  is an enlarged plan view of a cartridge loading unit constituting the cartridge refill system shown in  FIG. 5 ; 
       FIG. 7  is a perspective view of an ink injection part which is detached from the cartridge loading unit shown in  FIG. 6 ; 
       FIGS. 8 and 9  are views of the cartridge loading unit shown in  FIG. 6 , in which  FIG. 8  is a side view, and  FIG. 9  is a bottom view; 
       FIG. 10  is a view schematically illustrating the connection between a connection unit and the cartridge loading unit shown in  FIG. 8 ; 
       FIG. 11  is a front view illustrating an ink cartridge refill device which embodies the ink cartridge refill system according to the embodiment of the present invention; and 
       FIG. 12  is a side view of the ink cartridge refill device shown in  FIG. 11 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Herein below, an ink cartridge refill system according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components. 
   As shown in  FIG. 5 , the ink cartridge refill system according to an embodiment of the present invention includes a cartridge loading unit  10  in which an ink cartridge to be refilled with ink is loaded. The refill system also includes a plurality of ink tanks  50  to store therein refill ink. The refill system further includes an air compression pump  60 , a vacuum pump  70 , and a plurality of cylinders  40 , each of which is connected at the inlet end thereof to both the compression pump  60  and the vacuum pump  70  and is connected at the outlet end thereof to both an associated ink tank  50  and a connection unit  30 . The refill system further includes a plurality of hoses to connect the plurality of elements of the system to each other. The refill system further includes a plurality of sensors. 
   The construction of the cartridge loading unit  10  will be described herein below with reference to  FIGS. 5 through 8 . 
   In a manner similar to that described for the conventional refill system, the cartridge loading unit  10  of the refill system comprises a body in which an ink cartridge  1  is seated, and a cartridge holding part which closely and securely seats the cartridge  1  in the cartridge loading unit  10 . The cartridge holding part comprises a handle  11 , a sliding bar  12 , a link  13 , and a cushion member  14 . The nozzles  2  of the ink cartridge  1  are brought into close contact with an ink injection part  20  by the cartridge holding part comprising the above-mentioned elements  11 ,  12 ,  13  and  14 , so that the nozzles  2  of the ink cartridge  1  communicate with respective ink injection holes  21  of the ink injection part  20  in the same manner as that described for the conventional refill system shown in  FIG. 4 . 
   However, as shown in  FIGS. 7 and 8 , the inlet ports of the ink injection holes  21  are located on the rear surface of the ink injection part  20  unlike the conventional refill system. In the embodiment shown in  FIG. 7 , three fine ports are formed on the surface of the ink injection part  20 , with which the ink cartridge  1  is brought into close contact. The three fine ports of the ink injection part  20  define the outlet ports of the three ink injection holes  21 , so that the ink injection holes  21  must be bent in the ink injection part  20  (see  FIG. 10 ). 
   As shown in  FIG. 7 , the ink injection part  20  is preferably configured such that the ink injection part  20  can be detached from the cartridge loading unit  10 . Because the ink injection part  20  is detachably attached to the cartridge loading unit  10  as described above, it is possible to wash the ink injection holes  21  and to replace an existing ink injection part  20  with a new one when required. 
   As shown in  FIGS. 8 and 9 , a cartridge sensor  16  is provided on each of the cartridge loading units  10  and detects whether an ink cartridge  1  is loaded in the unit  10 . A lead wire to connect the sensor  16  to a control unit is inserted into a connection hole  15 . 
   In the refill system, it is preferred to configure the cartridge loading units  10  such that a particular model of ink cartridge  1  is used with each of the units  10  by varying the widths of the cartridge seats of the units  10  and the moving lengths of the sliding bars  12 . 
   Herein below, the connection unit  30 , which is used to connect both a plurality of ink injection hoses  41  and a second vacuum hose  71   b  to the ink injection holes  21 , will be described with reference to  FIGS. 8 through 10 . 
   The connection unit  30  is a body that is mounted to the rear surface of the ink injection part  20 , with three ink supply holes  31  and three ink suction holes  32  formed in the connection unit  30 . Of course, it should be understood that the connection unit  30  may be embodied as simple connection hoses. 
   The outlet ends of the three ink suction holes  32  are joined to the three ink supply holes  31 , respectively, so that the three ink supply holes  31  and the three ink suction holes  32  have the same outlet ports. In the above state, it is preferred to design the join angles of the three ink suction holes  32  relative to the three ink supply holes  31  such that the join angles are 90 degrees or less. The outlet ports of the three ink supply holes  31  and the three ink suction holes  32  are connected to the ink injection holes  21  via a plurality of connectors  22 . 
   As shown in  FIGS. 9 and 10 , the rear surface of the connection unit  30  is provided with three inlet ports of the ink supply holes  31  and three inlet ports of the ink suction holes  32 . The ink injection hoses  41  are connected to the ink supply holes  31  through three connectors  33 , respectively, while the branch hoses of the second vacuum hose  71   b  are connected to the ink suction holes  32  through three connectors  34 , respectively. 
   The three above-mentioned sets of holes  21 ,  31  and  32  communicate with each other to form three passages through which cyan ink, magenta ink and yellow ink respectively flow. The number of holes in each set of holes  21 ,  31 ,  32  may be changed according to the number of nozzles  2  of an ink cartridge  1  to be refilled with ink or the number of colors of ink to be injected into the cartridge  1 . 
   The construction of the other elements constituting the refill system will be described herein below with reference to  FIGS. 5 and 10 . 
   A piston (not shown) is movably placed in each of the cylinders  40 , so that, when pressurized air is supplied from the air compression pump  60  into the inlet ends of the cylinders  40  through an air hose  61 , the pistons move in the cylinders  40  toward the outlet ends of the cylinders  40 . Thus, different colors of ink stored in the cylinders  40  are supplied to the ink supply holes  31  of the connection unit  30  through the ink injection hoses  41 . An ink amount sensor  42  is provided on each of the cylinders  40  and detects the amount of ink supplied to the cylinder  40 , and outputs an ink amount signal to the control unit which controls the amount of ink supplied to the cylinders  40  in response to output signals of the sensors  42 . 
   An ink flow control valve  43  is installed in each of the ink injection hoses  41 . The ink flow control valve  43  may be configured as a one-way valve, such as an ON/OFF valve or a check valve. 
   The ink tanks  50  are respectively connected to the outlet ends of the cylinders  40  via a plurality of ink supply hoses  51 . Each of the ink tanks  50  is detachably installed using a mounting unit so that an empty ink tank  50  can be replaced with a new one. An ink tank sensor  52  is provided on each of the mounting units, detects whether an ink tank  50  is installed in the mounting unit, and outputs a signal to the control unit. 
   A valve  53  is installed in each of the ink supply hoses  51  that connect the ink tanks  50  to the outlet ends of the cylinders  40 . The valve  53  may be configured as a one-way valve, such as an ON/OFF valve or a check valve. An ink sensor  54  is provided in each of the ink supply hoses  51  at a position between the ink tank  50  and the valve  53 , and detects whether ink remains in the ink supply hose  51 . When the ink sensor  54  detects that no ink remains in the ink supply hose  51 , this means that the ink tank  50  associated with the ink supply hose  51  has been emptied. In the above case, the user replaces the empty ink tank  50  with a new one. 
   The air compression pump  60  is connected to the inlet ends of the cylinders  40  through the air hose  61 . A first auxiliary tank  62  is installed on the air hose  61  at a position behind the outlet port of the air compression pump  60 , with a pressure sensor  63  provided in the first auxiliary tank  62  to detect pressure in the tank  62 . The first auxiliary tank  62  temporarily stores therein pressurized air output from the air compression pump  60  and regulates the air pressure prior to supplying the air under regulated pressure to the cylinders  40 . An ON/OFF valve  64  is installed in the air hose  61  at a position behind the outlet port of the first auxiliary tank  62 , and controls the flow rate of the pressurized air supplied to the cylinders  40 . Of course, the ON/OFF valve  64  may be installed in the first auxiliary tank  62  in place of the air hose  61 . 
   The vacuum pump  70  is connected to the inlet ends of the cylinders  40  through a first vacuum hose  71   a . In the same manner as that described for the air compression pump  60 , a second auxiliary tank  72  is installed on the first vacuum hose  71   a  at a position behind the outlet port of the vacuum pump  70  and temporarily stores therein low pressure air output from the vacuum pump  70 , with both a pressure sensor  73  provided in the second auxiliary tank  72  to detect the pressure in the tank  72  and an ON/OFF valve  74  installed in the first vacuum hose  71   a  at a position behind the outlet port of the second auxiliary tank  72 . The second vacuum hose  71   b , which will be described later herein, branches from the first vacuum hose  71   a  at the second auxiliary tank  72 . 
   When vacuum pressure generated by the vacuum pump  70  is provided to the cylinders  40  through the first vacuum hose  71   a , the pistons move in the cylinders  40  toward the inlet ends of the cylinders  40 . Thus, different colors of ink are drawn from the ink tanks  50  into the cylinders  40 . In the above case, the ink flow control valves  43  installed in the ink injection hoses  41  must be closed so that the vacuum pressure can be provided only to the ink tanks  50  and not be provided to the ink cartridge  1 . If the ink flow control valves  43  are configured as one-way valves, it is not necessary to additionally control the operation of the valves  43 . 
   The vacuum pump  70  is also connected to the ink suction holes  32  of the connection unit  30  through the second vacuum hose  71   b . Thus, during the operation of the vacuum pump  70 , air and ink in the ink cartridge  1  can be drawn toward the vacuum pump  70  through the second vacuum hose  71   b.    
   An ON/OFF valve  75  is installed in the second vacuum hose  71   b . At a position behind the ON/OFF valve  75 , the second vacuum hose  71   b  branches into three branch hoses which are connected to the three ink suction holes  32 , respectively. A one-way valve  76  is installed in each of the three branch hoses of the second vacuum hose  71   b  to ensure the stable operation of the refill system. Of course, the number of branch hoses of the second vacuum hose  71   b  may be changed according to the number of colors of ink to be injected into the ink cartridge  1 . 
   A drain hose  81  extends from the second auxiliary tank  72  to a waste ink drain tank  80  so that waste ink, drawn from the ink cartridge  1  through the second vacuum hose  71   b  by the vacuum pressure generated from the vacuum pump  70 , can be drained to the drain tank  80 . An ON/OFF valve  82  is installed in the drain hose  81  and opens or closes the drain hose  81  to control the waste ink drainage operation. 
   An ink cartridge refill device  90 , which embodies the ink cartridge refill system according to the embodiment of the present invention, will be described herein below with reference to  FIGS. 11 and 12 . 
   As shown in  FIGS. 11 and 12 , a plurality of cartridge loading units  10  is installed on a plurality of stepped shelves of the device  90 . A plurality of cylinders  40  is installed on an upper shelf above the stepped shelves having the cartridge loading units  10 . The shorter cylinders  40   a , placed in the right-hand section of the device  90  in  FIG. 11 , are the cylinders to temporarily store different color inks therein. The longer cylinders  40   b , placed in the left-hand section of the device  90  in  FIG. 11 , are the cylinders to temporarily store black ink therein. The ink supply hoses  51  and the ink injection hoses (not shown) are neatly arranged on the back of the device  90 . 
   The information, input from the above-mentioned sensors and elements, is transmitted to the control unit which analyzes the input information and displays the operational status of the refill device  90  on a touch screen  92 . The user of the refill device inputs command signals using the touch screen  92 . 
   In the embodiment of  FIGS. 11 and 12 , the refill device is configured such that the nozzles of the ink cartridges are directed downwards. However, it should be understood that the refill device may be designed differently from the above-mentioned arrangement, according to the design of the shelves. 
   Herein below, a method of refilling ink cartridges using the refill device according to the embodiment of the invention will be described with reference to  FIGS. 5 through 12 . However, it should be understood that the order of the steps is not limited to the following description. 
   [Loading of Cartridge] 
   After completely loading an ink cartridge  1  in a cartridge loading unit  10 , the handle  11  is rotated upwards to bring the nozzles  2  of the cartridge  1  into close contact with the ink injection part  20 . 
   [Suction of Waste Ink from Cartridge] 
   Waste ink is drawn from the ink cartridge  1  through the second vacuum hose  71   b  by operating the vacuum pump  70 . This step is executed when necessary. In the above case, the valves  74  and  82  must be closed if the valves  74  and  82  are configured as ON/OFF valves. 
   [Injection of Ink into Cartridge] 
   The air compression pump  60  is operated to supply pressurized air into the cylinders  40  through the air hose  61 , so that the ink stored in the cylinders  40  can be injected into the cartridge  1  through the ink injection hoses  41 . In the above case, the valves  53  must be closed if the valves  53  are configured as ON/OFF valves. 
   [Suction of New Ink from Ink Tanks into Cylinders] 
   The vacuum pump  70  is operated to provide vacuum pressure to the cylinders  40  through the first vacuum hose  71   a , so that ink stored in the ink tanks  50  can be supplied to the cylinders  40 . In the above case, the valves  43 ,  75  and  82  must be closed if the valves  43 ,  75  and  82  are configured as ON/OFF valves. 
   [Regulation of Inner Pressure of Refilled Cartridge] 
   The vacuum pump  70  is operated to draw predetermined small amounts of air and ink from the refilled cartridge  1  through the second vacuum hose  71   b , so that the inner pressure of the refilled cartridge  1  can be regulated. In the above case, the valves  74  and  82  must be closed if the valves  74  and  82  are configured as ON/OFF valves. 
   As described above, the present invention provides an ink cartridge refill system for inkjet printers which removes predetermined small amounts of air and ink from a refilled ink cartridge and regulates the inner pressure of the cartridge after an ink cartridge refill process has been completed, and which can completely remove remaining ink from the cartridge at the initial stage of the ink cartridge refill process when necessary. 
   Furthermore, the refill system can remove remaining ink from both the ink injection holes and the gap defined between the nozzles of the ink cartridge and the ink injection holes after the ink cartridge refill process has been completed. 
   In addition, the refill system can be operated simply by manipulating a control button, and allows a user to manage the ink cartridge refill process while viewing a touch screen on which the entire process of refilling the ink cartridge is displayed. 
   Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.