Abstract:
The invention provides an ink replenishment cartridge and a writing instrument using the ink replenishment cartridge where new ink can be easily replenished in the writing instrument in which ink has been spent completely. The invention has a characteristic that the ink replenishment cartridge is provided with an ink tank having an ink discharge port, ink filled in the ink tank and a closing cap detachably mounted on the ink tank to close the ink discharge port and the ink tank is installed with the ink discharge port communicating with an opening at a rear end of a stem of the writing instrument from which a detachable tail cotter is removed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an ink replenishment cartridge for replenishing a writing instrument with ink, and particularly relates to an ink replenishment cartridge suitable for replenishing an encapsulated fiber type writing instrument provided with inner fiber in a stem with ink and the encapsulated fiber type writing instrument using the ink replenishment cartridge. 
         [0003]    2. Description of the Related Art 
         [0004]    As for a conventional type encapsulated fiber type writing instrument, as in an invention disclosed in Patent Laid-open Sho 61-42099, for example, inner fiber (a fiber bundle 5) folded in two is inserted into a stem (1) from an opening at its front end, a part left outside the stem (1) of the inner fiber (the fiber bundle 5) is impregnated with a setting agent, and after the setting agent is hardened, the part outside the stem (1) of the inner fiber (the fiber bundle 5) is cut to be a writing part (15b). 
         [0005]    For another conventional type technique, as in an invention disclosed in Patent Laid-open No. 2003-63190, for example, an encapsulated fiber type writing instrument where inner fiber (11) in a stem (12) and a writing part (a pen 14) are separate and when ink is completely consumed, the spent inner fiber (11) can be replaced with new inner fiber filled with ink (inner fiber for replacement 21) is disclosed. 
         [0006]    As the inner fiber is integrated with the writing part in the former encapsulated fiber type writing instrument, ink impregnated in the inner fiber can be smoothly supplied to the side of a front end of the writing part, compared with the latter encapsulated fiber type writing instrument where the inner fiber and the writing part are separate, and the former encapsulated fiber type writing instrument has advantages such as enough ink is discharged and writing is hardly patchy. 
         [0007]    Meanwhile, in the former encapsulated fiber type writing instrument, since the inner fiber is encapsulated in the stem in a compressed condition and the writing part is worked in the part protruded outside the stem of the inner fiber, the spent inner fiber cannot be replaced with new inner fiber filled with ink as in the latter prior art even if ink is completely consumed and it is difficult to replenish ink. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention is made in view of the above-mentioned situation and provides an ink replenishment cartridge that enables easily replenishing new ink in a writing instrument in which ink has been spent completely and a writing instrument using the ink replenishment cartridge. 
         [0009]    To address the problem, a first invention has a characteristic that there are provided an ink tank having an ink discharge port, ink filled in the ink tank and a closing cap detachably mounted on the ink tank to close the ink discharge port and the ink tank is installed with the ink discharge port communicating with an opening at a rear end of a stem of a writing instrument from which a detachable tail cotter is removed. 
         [0010]    In this case, a method of installing the ink tank in the opening at the rear end of the stem of the writing instrument may be fitting and screwing, and particularly from a viewpoint of facilitating attachment and detachment, it is desirable that the ink tank is screwed to the rear end of the stem of the writing instrument. 
         [0011]    A second invention has a characteristic that the ink tank is inserted into the opening at the rear end of the stem of the writing instrument and the ink discharge port is touched to inner fiber in the stem. 
         [0012]    A third invention has a characteristic that a small-diameter part is provided on the side of a front end of the ink tank, the ink discharge port is provided inside the small-diameter part, a vent is provided outside the small-diameter part and the vent is closed by the closing cap. 
         [0013]    A fourth invention is based upon a writing instrument that enables attaching and detaching of the ink replenishment cartridge into/from the opening at the rear end of the stem when the tail cotter is removed and has a characteristic that inner fiber folded in two is encapsulated in the stem. 
         [0014]    As the invention is configured as described above, the following action and effect are produced. 
         [0015]    According to the first invention, when ink in the writing instrument has been spent completely, the tail cotter of the writing instrument is removed. Meanwhile, if the closing cap of the ink replenishment cartridge is also removed and the ink tank is installed in the opening at the rear end of the stem of the writing instrument, ink in the ink tank is supplied to the inside of the stem. 
         [0016]    Therefore, ink is never spilt, a user&#39;s hand never becomes dirty, and ink can be easily replenished in the writing instrument. 
         [0017]    In addition, as the ink replenishment cartridge is configured so that it is installed at the rear end of the stem of the writing instrument, installation space is not required in the stem, compared with an ink replenishment cartridge installed in a stem of a writing instrument for example. Therefore, it can also be easily installed in a relatively thinnish writing instrument. 
         [0018]    Further, according to the second invention, ink is prevented from being left in the ink tank by surface tension and others when the ink is replenished in the stem of the writing instrument from the ink tank and ink can smoothly permeate the inner fiber from the ink tank. 
         [0019]    Further, according to the third invention, in a state in which the closing cap is mounted, the ink discharge port and the vent can be closed by the closing cap. 
         [0020]    When the ink tank is installed in the opening at the rear end of the stem of the writing instrument and ink is filled, air in the stem is guided into the ink tank via the vent as ink is discharged from the ink discharge port. Therefore, ink can be smoothly supplied to the stem from the ink tank. 
         [0021]    Further, according to the fourth invention, a writing instrument in which inner fiber folded in two is encapsulated and it is difficult to replace the inner fiber can be changed to the writing instrument where ink can be easily replenished owing to the ink replenishment cartridge. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a sectional view showing one example of an ink replenishment cartridge according to the invention. 
           [0023]      FIG. 2  is a sectional view showing one example of an encapsulated fiber type writing instrument using the ink replenishment cartridge according to the invention. 
           [0024]      FIG. 3A  is a sectional view showing a state before the ink replenishment cartridge is installed in a stem of the encapsulated fiber type writing instrument and  FIG. 3B  is a sectional view showing a state in which the ink replenishment cartridge is installed in the stem of the encapsulated fiber type writing instrument. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    Referring to the drawings, an embodiment of the invention will be described below. 
         [0026]    This ink replenishment cartridge A is provided with an ink tank  10  having an ink discharge port  12   b   1 , ink M filled in the ink tank  10 , a closing cap  20  detachably mounted on the ink tank  10  to close the ink discharge port  12   b   1  and packing  30  provided between the ink tank  10  and the closing cap  20 , and the ink replenishment cartridge is configured so an encapsulated fiber type writing instrument B described later can be replenished with ink M. 
         [0027]    The ink tank  10  is integrally formed by a body  11  of the tank forming space for accumulating ink M and a discharge port member  12  forming the ink discharge port  12   b   1 . 
         [0028]    The body  11  of the tank is substantially in the shape of a cylinder with a bottom, is provided with a male screw  11   a  for screwing the closing cap  20  described later on its outside face, and is provided on the side of a front end (on the side of a lower end in  FIG. 1 ) of the male screw  11   a  on the outside face with an annular projection  11   b  press-fitted to an inside face on the rear side of a stem  40  in the writing instrument B when the body is installed in the writing instrument B described later. 
         [0029]    The male screw  11   a  is formed so that it is screwed to an opening at a rear end of the stem of the writing instrument B with the ink discharge port  12   b   1  communicating when a detachable tail cotter is detached from the writing instrument B described later. 
         [0030]    The discharge port member  12  is fitted to the inside of an opening at a front end of the body  11  of the tank. 
         [0031]    The discharge port member  12  is integrally formed by a substantially cylindrical press-fitted part  12   a  press-fitted to the opening at the front end of the body  11  of the tank, a small-diameter part  12   b  formed in a smaller diameter than an inside diameter of the press-fitted part  12   a , and a joint  12   c  connecting the press-fitted part and the small-diameter part  12   b.    
         [0032]    The press-fitted part  12   a  is mounted on the body  11  of the tank fluidtight by press-fitting it to the opening at the front end of the body  11  of the tank. To further enhance fluid-tightness, a fluid-tight structure such as an annular protrusion may also be provided to an outside face of the press-fitted part  12   a  or an inside face of the body  11  of the tank. 
         [0033]    The small-diameter part  12   b  is formed substantially in the shape of a cylinder the outside diameter of which is smaller than the inside diameter of the press-fitted part  12   a  and an opening on the side of its front end functions as the ink discharge port  12   b   1  for pushing ink M out. 
         [0034]    The length of the small-diameter part  12   b  is suitably set so that a front end face of the small-diameter part  12   b  is inserted into the opening at the rear end of the stem of the writing instrument B described later and is touched to inner fiber  60  in the stem  40 . 
         [0035]    A corner part  12   b   2  is formed on a front end face of a circumferential wall of the small-diameter part  12   b  by chamfering the side of its inside face. 
         [0036]    The corner part  12   b   2  closes the ink discharge port  12   b   1  fluidtight by touching the corner part to an inside face at a front end of the closing cap  20  overall. 
         [0037]    The joint  12   c  is an annular part that connects a front end of the press-fitted part  12   a  and a rear end of the small-diameter part  12   b  and axially pierces a single or plural vents  12   c   1  (single in  FIG. 1 ). 
         [0038]    A peripheral part  12   c   2  of the joint  12   c  is formed in a larger outside diameter than the outside diameter of the press-fitted part  12   a  and is touched to the front end of the body  11  of the tank. 
         [0039]    The closing cap  20  is formed to fit with the shape on the front end side of the ink tank  10 , detailedly, includes a substantially cylindrical screwing cylinder  21  screwed on an outside face of the body  11  of the tank, a head  22  having a smaller diameter than a diameter of an inside face of the screwing cylinder  21  and formed substantially in the shape of a cylinder with a bottom and a packing pressing part  23  which is arranged to connect the head  22  and the screwing cylinder  21  and presses the packing  30  described later, and the packing  30  is fitted to an inside face of the packing pressing part  23 . 
         [0040]    The screwing cylinder  21  is provided with a female screw  21   a  to fit with the male screw  11   a  of the body  11  of the tank on the inside face. 
         [0041]    Plural vertical ribs  21   b  that function as anantislipping member are protruded in a circumferential direction on an outside face of the screwing cylinder  21  to facilitate turning the closing cap  20  around the ink tank  10 . 
         [0042]    The head  22  is formed substantially in the shape of the cylinder with the bottom a front end face of which is closed, an inside face of the bottom is touched to the corner part  12   b   2  at a front end of the discharge port member  12 , and a curved part  22   a  for holding the inside of the ink discharge port  12   b   1  fluidtight is formed. 
         [0043]    The packing pressing part  23  is an annular part that connects the screwing cylinder  21  of the closing cap  20  with the head  22 , and an annular concave portion  23   a  fitted to protrude the packing  30  described later backward is formed on its inside face. 
         [0044]    The packing  30  is a member substantially in the shape of a washer made of an elastic body such as rubber and elastomer resin in an example shown in  FIG. 1  and is compressed between the joint  12   c  of the discharge port member  12  and the packing pressing part  23  of the closing cap  20  to close the vent  12   c   1  of the discharge port member  12 . 
         [0045]    The packing  30  prevents ink M in the body  11  of the tank from leaking out via the vent  12   c   1  and if the ink M should leak out via clearance between the corner part  12   b   2  of the discharge port member  12  and the curved part  22   a  of the closing cap  20 , the packing acts so that the ink M is prevented from flowing outside. 
         [0046]    For an embodiment except the example shown in  FIG. 1 , the packing  30  in the shape of the washer may also be replaced with O ring. 
         [0047]    Next, the encapsulated fiber type writing instrument B configured so that ink M is replenished by the ink replenishment cartridge A will be described in detail. 
         [0048]    The encapsulated fiber type writing instrument B is provided with the substantially cylindrical stem  40 , the inner fiber  60  inserted into the stem  40 , the tail cotter  50  detachably mounted at a rear end of the stem  40  and a cap  70  detachably mounted at a front end of the stem  40 , and the side of a front end of the inner fiber  60  is protruded from the front end of the stem  40  to be a writing part  61 . 
         [0049]    The encapsulated fiber type writing instrument B enables attaching and detaching of the ink replenishment cartridge A into/from the opening at the rear end of the stem when the tail cotter  50  is removed. 
         [0050]    The stem  40  is integrally made of synthetic resin and is provided with the substantially cylindrical body  41  of the stem, a cap fitting part  42  arranged on the side of a front end of the body  41  and a tip  43  arranged further on the side of a front end of the cap fitting part  42 . 
         [0051]    A pair of vertical ribs  41   a  axially extended with the vertical ribs touched to the outside face of the inner fiber  60  are formed on the front side of an inside face of the body  41  of the stem and space between the pair of vertical ribs  41   a  functions as an air flowing groove  41   d.    
         [0052]    The pair of vertical ribs  41   a  prevents the side of the outside face of the inner fiber  60  from eating into the air flowing groove  41   d  between the pair of the vertical ribs  41   a  by arranging one vertical rib  41   a  close to the other vertical rib  41   a.    
         [0053]    The side of a front end of the air flowing groove  41   d  communicates with air flowing space s described later and the air flowing groove  41   d  makes air taken in from the outside via a vent  42   c  flow backward in the stem  40 . 
         [0054]    The plural pairs of vertical ribs  41   a  are arranged at a predetermined interval in a circumferential direction of the inside face of the body  41  of the stem. 
         [0055]    A female screw  41   b  to which the tail cotter  50  and the ink tank  10  can be screwed is formed on the inside face of the rear end side of the body  41  of the stem. 
         [0056]    A part on the front side of the female screw  41   b  of the inside face of the body  41  of the stem is an even press-fitted face  41   c  for press-fitting an annular projection  51  of the tail cotter  50  or the annular projection  11   b  of the ink tank  10 . 
         [0057]    The cap fitting part  42  is provided with an annular projection  42   a  for fitting the cap  70  over it on its outside face. 
         [0058]    An inner fiber fixing cylinder  42   b  is formed inside the cap fitting part  42  via the annular air flowing space s. 
         [0059]    The air flowing space s is extended forward in the stem and communicates with the vent  42   c  extended in a centrifugal direction of the stem on the way on the side of its front end. 
         [0060]    The plural vents  42   c  are provided at a predetermined interval in the circumferential direction of the stem  40 . 
         [0061]    According to the configuration, in normal writing, air is taken in from the vent  42   c  according to the discharge of ink M from the writing part  61 , is guided backward through the air flowing space s, is guided to the air flowing groove  41   d  between the pair of vertical ribs  41   a , and further, can be guided to the outside face of the inner fiber  60 . 
         [0062]    Therefore, the inner fiber  60  smoothly discharges ink M, sucking the air taken in from the outside. 
         [0063]    When ink M penetrates the air flowing space s by the application of the impact of a drop and others to the encapsulated fiber type writing instrument B, the ink M is prevented from flowing outside through the vent  42   c  by hitting the ink M on a front end face of the air flowing space s. 
         [0064]    The tip  43  is formed substantially cylindrically with the tip connecting with the inner fiber fixing cylinder  42   b.    
         [0065]    An annular protrusion  43   a  is formed on an inside face of the tip  43  and a part except the annular protrusion  43   a  of the inside face is formed substantially in the same diameter as an inside face of the inner fiber fixing cylinder  42   b.    
         [0066]    The annular protrusion  43   a  is provided to press the outside face of the inner fiber  60 , a flow rate of ink M flowing in the inner fiber  60  is adjusted to be appropriate, and a protruded dimension is set to an appropriate value to prevent the inner fiber  60  from being displaced in a longitudinal direction. 
         [0067]    The inner fiber  60  is long fiber made of polyester fiber or others, the fiber swollen more than the content volume of the stem  40  is folded in two, and is press-fitted into the stem  40  from the front end side of the stem  40  with the folded part at the head. 
         [0068]    In press-fitting, a part on the side of the front end (a part on the reverse side to the folded part) of the inner fiber  60  is left outside and the part on the side of the front end forms the writing part  61  described later. 
         [0069]    No coating made of synthetic resin or others is applied to the outside face of the inner fiber  60 . 
         [0070]    The part on the side of the front end of the inner fiber  60  partially inserted into the stem  40  as described above is cut to be a suitable dimension and the cut inner fiber  60  is impregnated with a setting agent x made of urethane resin or others. 
         [0071]    At this time, the setting agent x permeates the vicinity of the annular protrusion  43   a  on the side of the outside face on the front end side of the inner fiber  60 . 
         [0072]    The writing part  61  is formed by cutting the part on the front end side of the inner fiber  60  substantially in the shape of a shell after the setting agent x permeates as described above, is heated and is hardened. 
         [0073]    In an example shown in  FIG. 2 , a hatched part including the inner fiber fixing cylinder  42   b  on the front end side of the inner fiber fixing cylinder  42   b  is impregnated with the setting agent x. 
         [0074]    According to the configuration, the vicinity of the annular protrusion  43   a  on the outside face side of the inner fiber  60  is impregnated with the setting agent x and is hardened, and further, restoring force that tries to restore the inner fiber to an original condition from a folded condition acts on the inner fiber  60 . 
         [0075]    Therefore, the annular protrusion  43   a  and the inner fiber  60  impregnated with the setting agent x and hardened are strongly fitted by the restoring force, and the inner fiber  60  and the writing part  61  can be prevented from being axially displaced by fitting. 
         [0076]    After the writing part  61  is formed as described above, ink M is injected into the stem  40  from the opening at the rear end and the inner fiber  60  is impregnated with the ink M. 
         [0077]    The tail cotter  50  is a cylindrical member with a bottom having the substantially same shape as the body  11  of the tank of the ink replenishment cartridge A, a male screw  51  and an annular projection  52  are formed on an outside face on the side of its front end, the male screw  51  is screwed to the female screw  41   b  of the stem  40 , the annular projection  52  is press-fitted to the press-fitted face  41   c  of the stem  40 , and the opening at the rear end of the stem  40  is closed. 
         [0078]    The male screw  51  and the annular projection  52  are configured substantially in the same shape as the male screw  11   a  and the annular projection  11   b  respectively of the body  11  of the tank. 
         [0079]    According to the tail cotter  50 , the productivity of both the ink replenishment cartridge A and the encapsulated fiber type writing instrument B can be enhanced by forming the tail cotter  50  and the body  11  of the tank by common parts. 
         [0080]    The cap  70  is a substantially cylindrical member with a bottom for covering the cap fitting part  42 , the tip  43  and the writing part  61  respectively on the front end side of the stem  40 , and a drying prevention member  71  made of water absorption material such as polyurethane foam is inserted at the bottom to prevent the drying of a front end of the writing part  61 . 
         [0081]    The drying prevention member  71  is fitted by an annular protrusion  72  on the front end side of an inside face of the cap  70  to prevent the drying prevention member from being displaced backward. 
         [0082]    An annular protrusion  73  for fitting the cap to the cap fitting part  42  over the annular projection  42   a  is formed on the inside face on the rear end side of the cap  70 . 
         [0083]    Next, a procedure for replenishing ink M in the encapsulated fiber type writing instrument B by the ink replenishment cartridge A will be described in detail. 
         [0084]    First, the tail cotter  50  is removed from the stem  40  of the encapsulated fiber type writing instrument B. At this time, the tail cotter  50  can be easily removed from the stem  40  by turning the tail cotter  50  in a reverse direction to a screwed direction with the stem  40  fixed. 
         [0085]    In the meantime, as for the ink replenishment cartridge A, the closing cap  20  is removed from the ink tank  10 . 
         [0086]    The ink tank  10  is installed in the stem  40  from which the tail cotter  50  is removed. 
         [0087]    To explain more detailedly, as shown in  FIGS. 3(   a ) and  3 ( b ), the ink tank  10  the ink discharge port  12   b   1  of which is directed upward is screwed from the downside of the stem  40  the opening at the rear end of which is directed downward and the ink discharge port  12   b   1  is pressed on a rear end of the inner fiber  60  in the stem  40 . 
         [0088]    At this time, the inner fiber  60  in the stem  40  is pressed by the ink discharge port  12   b   1  of the ink tank  10  from the rear side. However, since the outside face of the writing part  61  integrated with the inner fiber  60  is fitted to the annular protrusion  43   a  with the outside face hardened by the setting agent x and its fitting force is also assisted by the restoring force of the inner fiber that tries to restore to the original condition from the folded condition, the inner fiber  60  is never displaced forward and the writing part  61  is never protruded from a constant position. 
         [0089]    When the writing part  61  of the encapsulated fiber type writing instrument B is directed downward, ink M in the ink tank  10  is discharged into the inner fiber  60  in the stem  40  by its own weight. 
         [0090]    At this time, since air in the stem  40  is taken in the ink tank  10  from the vent  12   c   1  as the ink M is discharged from the ink tank  10 , the ink M in the ink tank  10  is smoothly discharged into the ink tank  10 . 
         [0091]    In addition, as the ink discharge port  12   b   1  of the ink tank  10  is touched to the rear end of the inner fiber  60  in the stem  40 , the ink M can be prevented from being left in the ink tank  10  by surface tension and others and most of the ink M in the ink tank  10  can permeate the inner fiber  60 . 
         [0092]    Writing can be performed with the encapsulated fiber type writing instrument B without difficulty with the ink tank  10  mounted at the rear end of the stem  40  in place of the tail cotter  50 . 
         [0093]    Depending upon a user&#39;s choice, the ink tank  10  is removed and the original tail cotter  50  may also be mounted again.