Patent Document

CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a divisional application of Ser. No. 09/714,019, filed on Nov. 16, 2000, which itself is a divisional application of Ser. No. 09/011,842, filed on Feb. 13, 1998, now U.S. Pat. No. 6,183,155 B1, filed on May 26, 1998 and issued Feb. 6, 2001, which is based on and is a 371 International Application No. PCT/DE96/01530, filed on Aug. 12, 1996, which claims priority of German Application 195 29 865.9, filed on Aug. 14, 1995. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention concerns an implement for applying a liquid to a support by means of an applicator element. 
     2. Description of the Related Art 
     An implement is known from DE 41 15 682 and will now be described with reference to FIG.  11 . 
     Provided within a casing  2  is a divider wall  4 , above which a supply of freely movable liquid  6  is accommodated in the casing. Above the liquid  6  is a volume of air  7  which increasingly replaces the liquid as it is discharged. 
     At its lower end the casing  2  has a tapering front portion  8  with a through opening in which is held a wick  10  terminating in a writing tip  12  serving as an applicator element. Extending laterally beside the wick  10  through the front portion  8  is a vent bore  14 . A storage means  16  of capillary material which closely embraces the wick  10  is accommodated in the space between the front portion  8  and the divider wall  4 . The wick  10  completely fills an opening  18  provided in the divider wall  4  so that only the wick  10  projects into the liquid  6 . 
     The capillarities of the wick  10  and the storage means  16  are matched to each other in such a way that the capillarity of the storage means  16  is less than that of the wick  10 . It will be appreciated that the wick  10  does not involve a uniform degree of capillarity as it has larger and smaller spacings between its fibers or includes statistically distributed pores. 
     The important consideration is that the mean capillarity of the wick  10  in the region of the opening  18  is greater than the mean capillarity of the storage means  16 . That ensures that, when passing the implement over a support which is to be written upon with the writing tip  12 , liquid is sucked by capillary action through the wick  10  out of the supply of liquid in the casing  2  on to the support and at the same time air passes into the interior of the casing through the larger pores in the wick  10 , within the opening  18 , in order to replace the liquid which has been discharged in the writing operation. Because the storage means  16  involves a lower level of capillarity or larger capillaries in comparison with the capillaries of the wick  10  which serve for the feed of air to the liquid  6 , the storage means  16  which is directly in contact with the wick  10  is not sucked full with liquid so that its volume is available as a buffer volume if liquid is urged out of the supply of liquid into the wick for example due to thermal expansion of the air volume  7 . In that way the implement of FIG. 11 is extremely leak-proof in spite of a very large supply of liquid. 
     A particularity of that device is that the liquid to be applied to a support has to flow through the entire wick  10 , which naturally gives rise to a high level of flow resistance which limits the amount of ink issuing from the writing tip  12 . In practical operation that has the result from time to time that, when writing quickly or when quickly applying liquid, the implement does not give a satisfactory writing or application trace or image on the support. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to improve a liquid applicator implement as mentioned above as to permit a satisfactory applying of liquid to a support under widely varying conditions and using considerably different liquids. 
     A solution of this object is provided with an implement for applying liquid to a support including: a container for a freely movable liquid; a capillary storage means for temporarily receiving liquid upon a change in air pressure and/or temperature of the environment; an applicator element formed as a writing, drawing or brush tip or a print element; a capillary air inlet for compensation of liquid taken from the container; characterized in that a passage for conveying bridges partially or entirely over the distance between the container with liquid and the applicator element which passage is not directly in communication with the storage means and is of a lower capillary than that of the storage means. 
     In the implement according to the invention the liquid does not have to cover a long distance through a medium with a high level of capillarity, but is passes through a passage of low capillarity directly to the applicator element which therefore can be of a correspondingly short configuration and which no longer has a high level of flow resistance in regard to the liquid to be applied to a support, even with a high degree of capillarity. 
     Accordingly even large amounts of liquid can be applied to the support in a short time with the implement according to the invention, that is to say it is possible to write quickly, print very fast and so on. 
     Appended subclaims are directed toward advantageous embodiments of the inventive implement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described by way of example with reference to the accompanying diagrammatic drawings in which: 
     FIG. 1 is a view in cross-section through a first embodiment of an implement according to the invention, 
     FIG. 2 is a detail view on an enlarged scale of the implement shown in FIG. 1, 
     FIG. 3 is a view in section taken along line III—III in FIG. 2, 
     FIGS. 4 to  8  are cross-sectional views of different embodiments of the implement according to the invention, 
     FIG. 9 is a view in cross-section through an implement similar to FIG. 1, the applicator element being in the form of a printing element, 
     FIG. 10 is a view in cross-section through an implement similar to FIG. 2, the applicator element being in the form of a ball point tip, and 
     FIG. 11 is a view in cross-section through the known implement already described above. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to FIG. 1, a writing implement to the operated by hand comprises a casing  2  with a divider wall. Above the divider wall  4  there is a supply of freely movable liquid  6 , for example writing ink, above which there is in turn an air volume  7 . 
     Within casing  2  above divider wall  4  there is space for accommodating a large volume of liquid  6  (10 ml or more). 
     At the bottom the casing  2  terminates in a front portion  8  in which a wick  10  is held, the wick  10  terminating in an applicator or writing tip  12 . Extending laterally beside the wick  10  through the front portion  8  is at least one vent bore  14  or a vent passage. The wick  10  extends through a storage means  16  of capillary material which is disposed in the casing  2  below the divider wall  4 , into an opening  18  which is provided in the divider wall  4 , and which it completely fills. The storage means  16  embraces the wick  10  in such a way that it is at least in part in direct contact with the wick  10 . As in the FIG. 11 implement the capillarities of the storage means  16  and the wick  10  are matched to each other in such a way that the mean capillarity of the storage means  16  is less than that of the wick  10 , while the larger capillaries of the wick  10 , within the opening  18 , serve for the introduction of air into the supply of liquid  6  in order to replace by air the liquid discharged by the writing tip  12 . There is a considerable degree of freedom of choice for the material of the wick  10 . It may comprise for example acrylonitrile polymer, polyester or nylon fibers, or a capillary component which is produced in a mould. The storage means  16  may comprise fibrous, foam or plate-like material with capillary gaps therebetween. 
     In contrast to the state of the art the wick  10  is formed in its interior with a blind passage  20  which extends axially directly from the liquid  6  to the writing tip  12 . The dimensioning of the passage  20  is such that its capillarity is markedly less than that of the storage means  16  so that liquid passes through the passage  20  directly from the liquid supply  6  to the writing tip  12 . 
     It is advantageous if the capillarity of the passage  20 , when using normal writing inks, is less than that of a circular capillary of a diameter of 0.1 mm, preferably smaller than that of a capillary of a diameter of 0.5 mm. It is further advantageous if at the end of the passage  20  which is towards the writing tip  12  the wick  10  has capillaries whose capillarity is larger than that of the capillary air inlet which is disposed for example within the wick  10  in the region of the opening  18  and/or between the wick  10  and the inside wall of the opening  18  or at any location of the wick  10  between the divider wall  4  and the writing tip  12 . In the latter case the air passes transversely through the wick  10  directly into the passage  20 . That ensures that, when liquid issues from the writing tip  12  when the implement is used for writing on a support, air bubbles are sucked in through the opening  18  into the volume of the liquid  6 . 
     The embodiment illustrated in FIG. 1 in which the passage  20  is completely enclosed by the capillary material of the wick  10  ensures a reliable feed of liquid to the passage  20  on the one hand while on the other hand the storage means  16  which with its material of low capillarity is in direct contact with the wick  10  can reliably come into operation. 
     In the described embodiment of FIG. 1 the blind passage  20  is produced by a procedure whereby a per se known wick is received in a device having an internal bore whose diameter corresponds to that of the wick and a bar corresponding to the passage  20  to be formed is driven into the wick, in which case the wick advantageously comprises thermoplastic material and is heated to a temperature of for example 80° C. during the operation of driving the bar into the wick. 
     FIG. 2 is a view on an enlarged scale of the embodiment of FIG. 1, turned through 90° and with a modified configuration for the opening  18 . In this embodiment, as can be seen in particular from FIG. 3, the opening  18  is provided with slots  22  affording well-defined capillaries which serve for the feed of air into the liquid space  6  above the divider wall  4  in FIG. 1 or to the right of the divider wall  4  in FIG.  2 . When only the larger pores of the wick  10  are used to provide for the feed of air, the capillarity may be somewhat too large, that is to say the flow of ink may be too slight, for some situations of use. In contrast the slots  22  can ensure an accurately defined capillarity which is lower than that of the wick  10  but greater than that of the storage means  16 . 
     The embodiment shown in FIG. 4 does not have a passage formed by a blind passage  20  within the wick  10 , as in the embodiment of FIG. 1, but by two blind passages  24  and  26  defined within tube portions which are of U-shape in cross-section and which, extending along the wick  10 , lead from the divider wall  4  into the portion  8  and feed liquid directly to the lower region of the wick  10 . Otherwise the embodiment of FIG. 4 corresponds in terms of its function to the embodiment shown in FIG. 1, the passages  24 ,  26  only extending outside the wick  10  but directly adjoining same. 
     It is advantageous if the capillary of the passage  20 , when using normal writing inks, is less than that of a circular capillary of a diameter of 0.1 mm, preferably smaller than that of a capillary of a diameter of 0.5 mm. It is further advantageous if at the end of the passage  20  which is towards the writing tip  12  the wick  10  has capillaries whose capillarity is larger than that of the capillary air inlet which is disposed for example within the wick  10  in the region of the opening  18  and/or between the wick  10  and the inside wall of the opening  18  or at any location of the wick  10  between the divider wall  4  and the writing tip  12 . In the latter case the air passes transversely through the wick  10  directly into the passage  20 . That ensures that, when liquid issues from the writing tip  12  when the implement is used for writing on a support, air bubbles are sucked in through the opening  18  into the volume of the liquid  6 . 
     As is immediately apparent from FIGS. 1 and 4, the passages  20  in FIG. 1 and 24 and  26  in FIG. 4 are of considerable axial length which in normal writing implements is in the range that is at least greater than 0.5 cm whereby it is possible to circumvent the flow resistant of the wick  10  or the total flow resistance for the liquid to be applied can be considerably reduced. 
     The embodiment of FIG. 6 does not have a wick which leads directly from the supply of liquid  6  to the writing tip  13 . A tube portion  28  of material which is impervious to the liquid leads from the opening  18  into the front portion  8  and there feeds ink directly to the writing tip  13  held in the front portion  8 , through a passage  29  formed in the interior of the tube portion  28 . At their junction the tube portion  28  and the writing tip  13  are advantageously sealingly enclosed by the front portion  8 . Arranged around the tube portion  28  is a hollow wick  32  which directly adjoins the capillary material of the storage means  16  and extends from the opening  18 . The capillarities are so matched that the writing tip  13  which is in the form of a portion in the FIG. 6 embodiment is greater than that of the hollow wick  32 , at least in the opening  18  which in turn is greater than that of the storage means  16 . In that way the part of the hollow wick  32 , which is in the opening  18 , performs the function of feeding air to the supply of liquid  6  and charging the storage means  16  with a buffer liquid volume in the event of a rise in pressure in the air volume  7 , for example upon an increase in temperature. 
     The embodiment of FIG. 5 differs from that of FIG. 1 insofar as the wick is of a two-part nature, namely in the form of a hollow wick  11  leading to an applicator or writing tip  13 . The two parts  11  and  13  are advantageously sealingly enclosed at their junction by the front portion  8  so that the liquid reliably passes directly into the writing tip  13  through the passage  20 . In the illustrated embodiment the vent bore  14  is disposed at a location in the front portion  8 , remote from the writing tip  13 . It will be appreciated that venting or air intake may occur at any suitable location, for example also through larger capillaries of the writing tip  13 , directly into the passage  20 . 
     The embodiment of FIG. 6 does not have a wick which leads directly from the supply of liquid  6  to the writing tip  13 . A tube portion  28  of material which is impervious to the liquid leads from the opening  18  into the front portion  8  and there feeds ink directly to the writing tip  13  held in the front portion  8 , through a passage  29  formed in the interior of the tube portion  28 . At their junction the tube portion  28  and the writing tip  13  are advantageously sealingly enclosed by the front portion  8 . Arranged around the tube portion  28  is a hollow wick  32  which directly adjoins the capillary material of the storage means  16  and extends from the opening  18 . The capillarities are so matched that the writing tip  13  which is in the form of a wick portion in the FIG. 6 embodiment is greater than that of the hollow wick  32 , at least in the opening  18  which in turn is greater than that of the storage means  16 . In that way the part of the hollow wick  32 , which is in the opening  18 , performs the function of feeding air to the supply of liquid  6  and charging the storage means  16  with a buffer liquid volume in the event of a rise in pressure in the air volume  7 , for example upon an increase in temperature. 
     In the embodiment shown in FIG. 7 a passage  34  leads directly from the supply of liquid  6  into a central region of the wick  10  which terminates downwardly in the writing tip  12  and which is connected upwardly to the capillary storage means  16  through a further divider wall  36  in the casing  2 . 
     The feed of air to the supply of liquid  6  occurs through the vent bore  14  into the space in which the storage means  16  is arranged and from there through the larger pores of the part of the wick  10 , which is in an opening  38  in the further divider wall  36 , into the passage  34 . The relationships between the individual capillarities correspond to those of the embodiment of FIG. 1, the opening  38  performing the function of the opening  18  of the embodiment of FIG.  1 . 
     The embodiment of the implement shown in FIG. 8 corresponds to that of FIG. 6, but here the passage  29  in FIG. 6 is replaced by a passage  34  in FIG.  8  and the hollow wick  32  in FIG. 6 is replaced by a wick portion  40 . Venting occurs through the capillaries of the part of the wick portion  40 , which is in the opening  18 , wherein the capillarity of the wick portion  40  must again be less than that of the writing tip  13  but greater than that of the storage means  16  so that under normal conditions the storage means  16  does not suck itself full of ink. 
     The embodiment of FIG. 9 corresponds to that of FIG. 5 but here the hollow wick  11  terminates directly in a printing element  42  serving as the applicator element. While the embodiments of FIGS. 1 to  8  are intended for a mode of operation in which the liquid is applied to the support by mechanical contact and relative movement between the writing tip  12  and the support, the implement of FIG. 9 operates in such a way that the printing element  42  is connected to an electrical actuating device (not shown) for spraying quantities of liquid on to a support in a deliberate and targeted manner. 
     The embodiment of the implement shown in FIG. 10 corresponds to that shown in FIG. 5, with the exception that fitted into the front portion  8  is a per se known ball point tip  44  which is applied with writing liquid directly from the writing tip  13  of the embodiment shown in FIG. 5, which is in the form of a wick portion. 
     In all embodiments of the implement according to the invention as shown in FIGS. 1 to  10  it is possible to use the most widely varying applicator elements such as felt pen tips, fine painting and drawing tips, brush tips, printing elements, ball point tips, other writing tips and the like. 
     Instead of the wicks of wick portions it is also possible to use individual capillary passages or ducts whose capillarity corresponds to the mean capillarity of the wick replaced thereby such capillary passages or ducts extend in functional terms parallel to the wick or transversely through the wick which they replace, depending on the function which they perform. For example in the embodiment of FIG. 5 the hollow wick  11  can be replaced by a passage or duct which performs the function of the passage  20 . One or more capillary passages or ducts which connect the passage  20  to the storage means  16  can lead transversely through the wall of the passage or duct which replaces the hollow wick  11 . 
     It will be appreciated that the above-described embodiments of the invention have been set forth solely by way of example and that various modifications may be made therein without thereby departing from the scope of the invention.

Technology Category: 7