WO2005016661A2

WO2005016661A2 - Writing, decorating and printing liquid delivery device

Info

Publication number: WO2005016661A2
Application number: PCT/GB2004/003466
Authority: WO
Inventors: Julia Davidson; Rollo Metcalfe
Original assignee: Julia Davidson; Rollo Metcalfe
Priority date: 2003-08-11
Filing date: 2004-08-11
Publication date: 2005-02-24
Also published as: GB0318764D0; WO2005016661A3

Abstract

Embodiments of the invention comprise a receptacle (4) formed from hydrophilic material which interact with a liquid (8) inside an internal chamber (6) of the receptacle in combination with the surface tension (12) of the liquid produced at an aperture (10). Upon breaking this surface tension, liquid flows from the receptacle under capillary action. Embodiments of the invention comprise a narrow conduit (211) for the passage of ink out of the internal chamber (206).

Description

Liquid Delivery Device

The present invention relates to a liquid delivery device. The invention has particular applications for liquid delivery devices with writing and printing applications, including pens, including glue pens and correctional fluid pens, and printing cartridges. The invention also relates to a writing tip for pens.

Pens commonly used today, for example ballpoint pens, are relatively complex to manufacture and require high precision in the assembly process and precision materials. The key to the ballpoint pen is, of course, the ball in the writing tip which acts as a buffer between the material a writer is writing upon and quick-drying ink inside the pen. The ball is installed in a socket, rotating freely within the socket and rolls out the ink that is continuously fed from the ink reservoir within the pen, which is usually in a narrow plastic,, tube filled with ink.

There are a number of problems associated with existing pen designs.

Academic research points out that the most important disadvantages of ball- points are that they need to be held at an awkward angle, and pressed down on the paper, which can lead to pain and muscle fatigue.

Felt tip pens, including highlighters, which have a very limited life may easily dry out if left uncapped.

Disadvantages of fountain pens include a delicate mechanism, reliability and the need for maintenance (cleaning by the owner, or professional maintenance carried out by the pen manufacturer or a specialist company). A further criticism of all existing pens is their shape. Pens are the (or one of the) only hand tools built in a cyclindrical shape, and this can lead to discomfort and pain over long periods of use. Although pens could be made in other shapes, the existing writing mechanisms are substantially cylindrical, and form follows function.

It has been observed in an academic study : "40% of girls and 25% of boys of school-leaving age could be counted as suffering pain when writing... surveys with higher achieving pupils of the same age pointed to an even higher proportion of pain. Tension tremors can occasionally be observed in children under stress... Occasionally, the pain and tension can be so intense that pupils become unable to use their writing hand. This is often related to overuse at examination time, but cases in younger children appear to be on the increase worldwide, especially in countries where the education system is highly competitive." A British government report states that one in three teenage boys and one in four girls says that they only write when they have to, and even then they write as little as possible.

There is therefore scope for the introduction of an ink delivery device which needs less pressure to deliver the ink, and allows a non-cylindrical shape to help ease pain and muscle fatigue which has particular application as a writing tool.

This ink delivery device has a writing mechanism that may create an improved writing experience. This may be pleasant and convenient for the able-bodied, and may make the difference between writing and not being able to write at all for some disabled people. There is therefore scope for an ink delivery system which overcomes these disadvantages.

The ink delivery device may be produced in disposable or reusable forms. Disposable versions of the device are preferably formed of biodegradable material to provide an environmentally-friendly device.

In a first aspect of the present invention there is provided a liquid delivery device comprising a receptacle formed at least in part of hydrophilic material, said receptacle having an internal chamber which opens through a first aperture in the receptacle, wherein, when the chamber is filled or partially filled with liquid and a force acts upon the liquid so that the liquid abuts the first aperture, an adhesive reaction between the liquid and the hydrophilic material of the receptacle, in combination with the surface tension of the liquid at the aperture, retains the liquid within the receptacle and, when the surface tension is broken, liquid flows from the chamber through the first aperture under capillary action.

In a second aspect of the invention, there is provided a liquid delivery device comprising a receptacle formed at least in part of hydrophilic material, said receptacle having an internal chamber which opens through a first aperture in the receptacle, wherein, the first aperture comprises a narrow conduit.

Other aspects and features of the invention are set out in the claims and are discussed in more detail below.

Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Fig. 1 is a diagram illustrating a liquid-delivery device according to the present invention in cross-section, and the manner in which liquid is delivered on to a surface, such as paper;

Fig. 2 is a diagram of an embodiment of the present invention; Fig. 3 is a diagram of an alternative embodiment of the present invention and also illustrates the forces which act upon the liquid;

Fig. 4 is a diagram illustrating the manner in which a writing tip portion of the liquid-delivery device of the present invention may be shaped to facilitate smooth liquid-delivery; Fig. 5 is a diagram illustrating alternative methods of constructions and shapes of writing tips of the liquid-delivery device;

Fig. 6 is a diagram illustrating the manner in which a separately formed writing tip may be joined with the receptacle of the liquid-delivery device of the present invention; Fig. 7 is a diagram illustrating a manner in which added precision may be introduced into the delivery of the ink from the liquid delivery device; .

Fig. 8 is a diagram outlining possible manufacturing processes of liquid- delivery devices according to the present invention;

Fig. 9 is a diagram illustrating the manner in which the ink transfer process can be shaped/modified by the arrangement of the ink delivery aperture into arrays;

Fig. 10 illustrates a further alternative embodiment of the present invention; and

Fig. 11 is a diagram illustrating the manner in which writing tips may be shaped to control the flow of ink from closed ink reservoirs containing liquid ink, and open ink reservoirs containing viscous or fhixotropic ink.

Referring now to Figure 1, operation of the present invention, and the manner in which liquid may be delivered onto a paper surface, will be discussed. As seen in Figure la, the liquid delivery device 2 comprises a receptacle 4, which has an inner hollow chamber 6 which may be filled or partially filled by liquid 8, which may be ink, liquid glue, correctional fluid or other desired liquids. In most cases the hollow chamber will comprise the volume within receptacle 4, but it could be a separate component if it was desired to have the outer receptacle made of a different material which may not control the liquid flow as well. The liquid-delivery device has an aperture 10 through which liquid may enter and flow from the device. The device is oriented in this embodiment so that the aperture is situated at the base of the device. In such a case, the force of gravity will tend the liquid towards the aperture such that it abuts the aperture. In embodiments of the present invention, the receptacle is comprised at least in part from hydrophilic material 14. At the very least the chamber 6 is lined with hydrophilic material 14. It has been found that through a combination of an adhesive reaction between the liquid and the hydrophilic material of the receptacle with the surface tension of the liquid at the aperture 12 is sufficient to retain the liquid within the receptacle.

A close up of the aperture 10 is shown in Figure lb. Surface tension 12 forms a lattice where liquid meets air and is produced by cohesive force between molecules of the liquid at the surface. Contact with another surface or any other object breaks this lattice and, in the present invention, allows the liquid to flow. For delivery of the ink from the receptacle it is required to break the surface tension by, for example, bringing the aperture into contact with a page of paper. Moving the receptacle across the page whilst maintaining contact with the page allows the user to form shapes such as alphanumeric characters or images as desired. Once brought into contact with the surface of a page of paper, as shown in Figure lc, liquid flows under capillary action from the chamber through the first aperture in the direction 16. To replace the ink 8 which is evacuating the chamber 6, air passes back through the aperture 10 in the direction 18. When the receptacle is lifted from the paper the capillary action ceases and the lattice of the surface tension reforms to retain the ink 8 within the chamber 6 once more.

As mentioned above, the invention also extends to the use of glue pens and corrective fluid pens. In these cases however, care must be taken to carefully select the chemical composition of the glue or correctional fluid to ensure that reaction does not occur between the liquid and the air at the aperture 10 to clog or block the aperture.

The invention may also extend to a device using other materials which attract one another. For example, an embodiment of the present invention is provided with a glass receptacle for the delivery of some acids, for example for use in laboratory experiments or for the delivery of mercury from a gold, or gold- lined receptacle. Mercury is attracted to gold and, as such, a similar reaction between the liquid and the hydrophilic material as described above is emulated.

Suitable materials might also be employed in the receptacle to control, for example, the delivery of blood or plasma onto strips of paper impregnated with reagents for experiments.

Due care and attention should also be taken of the surface tension of the liquid in question depending on the particular application. For example, mercury which is attracted to gold, has a surface tension which is more than 6 times as strong as that of the surface tension of water. On the other hand, devices utilising ethyl alcohol as the liquid to be delivered may pose problems due to the relatively low surface tension of ethyl alcohol, approximately one third that of water. Further, although it is desirable that the liquids to be employed should be environmentally friendly, there is the possibility to substitute or add various liquids to modify the viscosity and surface tension.

The receptacle 4 may be comprised of clear or translucent material in some embodiments of the invention. This allows a user to see when the volume of ink within the chamber 6 is diminishing and provides advance warning that a replacement, or refilling, of the receptacle may be required.

The present invention also has application for printing cartridges for printers and in such applications, the components of Figure 1 are manufactured on a small scale to provide the resolution required in such applications. An array of receptacles of Figure 1 is formed to form the printhead, each receptacle serving the purpose of an ink reservoir of the printhead, the aperture 10 being a nozzle of one of the ink reservoirs. Mechanisms well known may be employed to lift and lower each receptacle to form a printed image as desired on a page or other substrate.

Referring now to Figure 2, operation of one embodiment of the present invention which has particular application for use as a pen will now be described. In this embodiment, the pen device 102 is comprised of a receptacle, which in this case is a hollow barrel 104 forming an internal chamber 106 partially filled with ink 108. The barrel further comprises a writing tip portion 134 which assists the flow of ink through the aperture 110 and/or the formation of the surface tension lattice 112 at the aperture 110. The writing tip portion 134 may also assist a user to grip the pen 102 comfortably.

In some embodiments of the present invention, the device also comprises a second aperture 130 provided at the end of the barrel which is opposite from the aperture 110 through which the chamber 106 may be filled with ink. The pen device is provided with a closure 132 to seal the aperture 130 thereby avoiding accidental leakage and/or drying of the ink from or through this aperture.

As shown in Figure 2b and 2c, the aperture 110 of the pen 102 may be brought into contact with a sheet of paper 136 for the purposes of writing at 138.

In some embodiments of the present invention, the closure 132 for aperture 130 is resealable to allow re-use of the device, by screw, snap-fit, or other suitable means. This is advantageous in that a user has the option of emptying out the chamber 106, cleaning it, and replacing the ink 108 with ink of another colour or other fluid of choice.

As is shown, a device according to the embodiment of Figure 2 comprises only two components: the barrel 104 and the closure 132, each of which may be conveniently manufactured by plastics material. Embodiments of the present invention therefore offer significant cost and manufacturing advantages over existing pens.

Pens according to the present invention may contain more ink for their size than any existing pen; the ink reservoir may comprise the entire volume of the barrel or receptacle, thereby extending the life-expectancy of mass-produced pens. However, the device could be produced in any size desirable to suit the desired life of the device. The shape could also be modified according to desires, for example it will be possible to mould the barrel to provide novelty designs, and, more importantly, to shape the 'barrel' of the pen to suit the writer's hand rather than the mechanism inside. Figure 3 illustrates an alternative embodiment of the present invention. In this embodiment, the pen device 202 comprises a barrel 204, a chamber 206 filled with ink 208, and has an aperture 210 at the end of a narrow conduit 211. Also illustrated is a third aperture 228 situated in the writing tip 232. The various forces acting on the ink during the ink delivery process are now described as follows. Surface tension is formed at 212 as described above and is a force acting on the ink in the direction illustrated by reference numeral 220. Adhesive force bonds the ink to the side of the narrow conduit as shown at 222 and at 224. This adhesive force is enhanced by the reduced diameter of the conduit; reducing the radius of the conduit by a factor of two reduces the flow rate by a factor of 16, producing a "drag" effect on the ink as it flows. An advantage of the provision of this feature is that it means that the pen will not leak or ooze ink when the tip is left in contact with the paper or when the user is writing slowly. Capillary action at the point 226 draws the ink through the conduit 211 and the aperture 210 when the surface tension 212 of the ink 208 is broken. As the ink 208 is drawn out through the conduit 211 and aperture 210, air is sucked in through the third aperture 228 in the direction 230 as shown to replace the ink leaving the pen device. It is not essential that the third aperture 228 is situated in the writing tip 232 or below the liquid level as is shown in Figure 3, but it has been found that by placing it so, the flow of ink through the narrow conduit 211 is enhanced thereby ensuring a smoother writing action. Further, the use of the narrow conduit 211 as illustrated inhibits the flow of air back into the barrel 204 through the aperture 210, leaving air to be drawn through the third aperture 228.

The ink or liquid may also be specifically chosen to provide a smoother writing or delivery action. The provision of a narrow conduit in a liquid delivery device to retard or control the flow of ink is an important one and as such may be provided independently.

With reference to Figure 4, a manner in which the writing tip may be shaped to facilitate smooth writing is now discussed. As shown in Figure 4a, the writing tip 134 may be shaped so that the lower surfaces of the writing tip 140a and 140b lie at an angle to the axis of the pen. In use, these surfaces would lie parallel with the surface 136 upon which ink transfer is to take place. Such an arrangement persuades a writer to automatically incline the pen at the angle 142 to the vertical 140 which is a natural position for a writer to hold a pen.

The writing tip 134 may be of a relatively small size and, as such, it may be difficult for a user to determine the correct or optimal orientation of the writing tip to ensure smooth writing. It is therefore advantageous to include a marker 138 or other form of indication on the writing tip 134 to indicate the direction of optimal orientation of the writing tip 134 for the user to use it. This marker may comprise simply an indicator for the user to register the direction in which the pen should be oriented or may comprise a textual message, for example "this way up" or combination of these methods.

It will be appreciated that the writing tip could be shaped in almost any way imaginable to suit the taste of the user. For example, and as shown in Figure 4b, the writing tip 134 may be symmetrically rounded such that the lower portions 140a and 140b provide a substantially spherical writing tip. A further alternative writing tip design may be oval in shape, to produce a writing line that is wider than it is high, for italic or script-style writing. A yet further alternative writing tip design is shown in Figure 4c. In this case, the writing tip 134 is formed separately from the barrel 204 as will be discussed further below. The third aperture 230 is shown for the inlet of air to the internal chamber 206 as the narrow conduit 211 is too narrow to facilitate both flow of ink onto the paper from the chamber 206 and the flow of air from outside the writing tip 134 back through the narrow conduit 211 into the chamber 206. Ink is slowed down only in the narrowest part 252 of the conduit 211. Capillary action works the entire length of the narrow conduit 211 as shown by 250.

Figure 5 is a diagram illustrating alternative methods of construction of the writing tip and alternative shapes of the writing tip. The writing tip and barrel may be moulded in a number of designs using any of known moulding techniques. In the illustrated embodiment, the aperture for the flow of ink onto the paper is defined by an opening 118 which is substantially larger than the narrow conduit 110b. The large opening helps to define the size of the pen stroke and the narrow conduit 110b, at least in part, defines the rate of flow of ink from the chamber 106 to the aperture 110a. In this embodiment, the aperture has a portion 260 which projects into the chamber 106 and it has been found that this shape enhances the flow of ink and, further, can be shaped to provide a length of conduit as desired, to control the flow of ink. Figure 5b is a small scale illustration of Figure 5a where the third aperture 230 is clearly shown as being within a recessed portion 262 of the writing tip 134. This advantageously means that accidental contact by a user pen lid or other object with the third aperture 230 is avoided. Such accidental contact is undesirable as flow of ink would occur through aperture 230 in precisely the same fashion as through aperture 110 as described above.

Figure 5 c illustrates an embodiment of the present invention in which the writing tip and barrel portions are formed from two separate parts. A metal nib 234 is conjoined with the plastic barrel portion of the writing tip 134 as shown. Such an arrangement is advantageous in that manufacturing of writing tips with a narrow conduit as shown in Figure 5 may be more easily carried out in metals than by the moulding of plastics material. Of course, it will be appreciated that the separate writing tip and its interface with the barrel could comprise almost any shape as long as they fitted together in a secure fashion. Introduction of another component (i.e., the separate writing tip) still means that the invention according to this embodiment offers significant advantages in terms of number of component parts over existing pen designs.

With reference to Figure 6, a manner in which a separate writing tip may be conjoined with the barrel or receptacle of the embodiment of Figure 5b is discussed. In this embodiment, the metal writing tip is denoted by reference numeral 334 and is arranged to be inserted into the barrel 304 of the pen device

310. In this embodiment, the writing tip is provided with an integral collar 306 around the periphery of the writing tip to rest against the extreme edge of the barrel 312 as shown which adds mechanical strength to the writing tip and barrel and prevents the barrel splitting when excess pressure is placed upon the writing tip 334. To enhance the grip of the writing tip 334 within the barrel

304, the writing tip is provided with a long waist portion 308 to ensure increased friction and therefore stability to the device. It will be appreciated that other suitable methods of fixing the writing tip 334 to the barrel 304 may be employed.

Referring now to Figure 7, a manner in which added precision may be introduced to the delivery of ink or other liquids from devices according to the present invention is now discussed. As discussed above, the use of hydrophilic materials is a useful feature which may be employed in the present invention. However, by strategic use of hydrophobic materials, i.e. materials which have a repellent action upon water and water-based liquids, the flow of ink from the receptacles may be retarded as desired thereby adding control and precision to the ink delivery system which may be especially useful in small-scale applications of the present invention. This may have particular application in printing cartridges. As shown in Figure 7a and Figure 7b, a ring of hydrophobic material 400 is introduced around the aperture 402 to inhibit the flow of ink 408 from the aperture 402. This is advantageous in that it may be desirable in some embodiments of the present invention to retard any surplus liquid which may continue to flow after the breaking of the surface tension in the aperture 402. The hydrophobic material could be moulded into the hydrophilic writing tip 434 or it could be applied later using known moulding techniques or applied by adhesives or any other suitable method. The hydrophobic material 400 could also be applied to the internal bore of the aperture 402.

Due to the reduced number of components in embodiments of the present invention, the manufacturing process is greatly simplified. The steps in one such manufacturing process are shown in Figure 8a where at process step 500 the receptacle 502 is formed. At process step 504, the barrel 502 is filled with ink 506 through the aperture 510 in the direction 508 as shown. The closure 514 is then applied in the direction 515 to seal the barrel 502 in process step 512. In process step 516, a punch 522 forms the aperture 518 by punching in the direction 520 as shown. At process step 524 a cap or lid 526 is placed upon the barrel 502 in the direction 528 as shown.

An alternative manufacturing process where the ink delivery device comprises a separately formed writing tip is shown in Figure 8b. At process step 550 the barrel is formed in the same fashion as shown in Figure 8a. At process step 552, the barrel is filled with ink through aperture 554 in the direction 556 as shown. In this case, no further aperture is required for filling the barrel 502 with ink as the aperture 554 is sufficiently large for filling to take place through this aperture. At process step 558 the separately formed writing tip 560 is inserted in the direction 562 as shown. At process step 564 the cap 566 is placed upon the barrel 502 in the direction 568 as shown.

Referring now to Figure 9a it will be seen that it will be possible to introduce various writing affects by shaping and/or arranging the first aperture of any of the embodiments of the present invention according to desire. For example, the first aperture could comprise a cluster of apertures and that, for example, a pen could be produced with a shaped cluster of apertures that left a mark on the paper that was wider than it was high to produce the effect of an italic pen, fountain pen or other similar device. Alternatively, and as shown in Fig 9b, the cluster of apertures could be positioned in a long row, to emulate the effect of a broad-tipped magic marker pen. The introduction of hydrophobic materials to the cluster of apertures in such cases is particularly advantageous to avoid excess flow of ink through the cluster of apertures. In such embodiments, the hydrophobic material might surround the cluster of apertures to keep the ink in a controlled area.

Referring to Figure 10, a further alternative embodiment of the present invention is shown. In this embodiment, the liquid delivery device 702 comprises a receptacle or barrel 704 with an internal chamber 706 which may be filled with liquid, such as ink 708. The aperture 710 comprises an array or cluster of smaller apertures or an array of fibrous apertures formed, for example, from a filter. In use, the ink flows through the cluster/array of smaller apertures (in the case of the filter, the ink flows with the grain of the filter) and air is sucked back into the chamber through the aperture 730. Figure 10 also shows air bubbles 732 in the ink 708 which have been sucked through aperture 730. Referring now to Figure l la, operation of one embodiment of the present invention which has particular application for use as a pen will now be described. In this embodiment, the pen device 102 is comprised of a receptacle, which in this case is a hollow barrel 104 forming an internal chamber 106 partially filled with ink 108. The barrel further comprises a writing tip 134 which assists the flow of ink through the aperture 110 and/or the formation of the surface tension lattice 112 at the aperture 110 as will be discussed below with reference to Figures 1 lb, 1 lc and 1 Id. A feeder tube 601 links the internal chamber to the writing tip, and may also assist a user to grip the pen 102 comfortably.

A 'weir'-type valve 602 allows air to enter the internal chamber to replace the ink that flows out from the aperture 110 in the writing tip 134, and a 'collector' -type device 603 absorbs temporary surges in the ink due to changing temperature and air pressure.

'Collectors' and 'weirs' are well known in the art. In embodiments of the present invention, the weir employed uses hydrophobic plastic, but this is not essential to the invention. A traditional 'weir' could be used instead.

The surface tension lattice that forms when a liquid meets air tries to become as small as possible. For this reason the collector 603 takes the shape of a cone, with the narrow end towards the ink reservoir and the broader end pointing outwards, away from the ink reservoir. In embodiments of the present invention, the collector consists of a metal cone.

When temperature or pressure change brings about a surge of ink, the ink floods into the cone or series of cones, where it is held in position by the surface tension lattice. As the relative pressure inside the ink reservoir reduces (say, when ink leaves the pen through the nib or writing point by writing) this surface tension lattice moves to the narrower end of the cone, returning the ink to the reservoir.

In fountain pens, the collector takes the form of a series of "V" shaped grooves in the plastic or hard rubber feeder under the nib. In rollerball pens, the collector takes the form of a series of sacked disks, visible in models with transparent barrels. Figures lib and l ie show writing tips suitable for use with liquid ink stored in a closed ink chamber. A hydrophilic plug 604 is inserted into a socket 605 of a hydrophilic writing tip 606. Vanes 607 and 608 on the sides of the plug 604 wedge the plug 604 firmly in position while keeping a narrow gap around the periphery of the plug 604 open for ink to be attracted down by capillary action until stopped by the surface tension lattice 112 that forms on contact with the air. Vanes 607 and 608 are integrally moulded with the plug 604, projecting from the plug 604 surface. Vanes 607 delay the flow of ink, slowing the speed of the ink as it flows through the socket 605. In embodiments of the invention, the vanes 607 are formed to form one or more conduits for the ink flow through, the conduits being shaped to suit the particular application, for example in a circuitous route around the plug 604 in a spiral shape so that, upon flowing from the socket 605, the ink flows around the plug in the spiral, thereby being slowed as it leaves the socket 605. Vanes 608 have a sharp edge on the surface which is distal from the plug 604 in order to wedge the plug 604 firmly in place in the socket 605 by engaging with the inside surface of the socket 605. When this tip touches the paper, Hie surface tension lattice is broken and the ink marks the paper. When the tip is moved across the paper, ink is drawn down from the ink chamber and smoothed into a line by the face of the plug. Problems can arise in attempting to provide a writing tip with an aperture which provides a sufficiently broad writing line. If the aperture is too large, the effectiveness of the capillary action drawing the ink 108 from the chamber 106 is reduced. Further, the creation of the surface tension lattice 112 may also be hindered. On the other hand, if the aperture is small, which helps to provide an effective capillary action and surface tension lattice, the writing line may be too narrow or small. The provision of the plug 604 overcomes these problems as it provides a means to allow an aperture of sufficiently small or reduced effective cross-sectional area around the periphery of the plug but, as the aperture is spread across a greater effective cross-sectional area corresponding to the cross-sectional area of the socket 605, a sufficiently large writing line may be developed when the pen is used.

In the example given above, the effective writing aperture is shaped around the periphery of the plug, providing an aperture for ink passage through the socket 605 which has the same diameter of the socket itself, but a reduced effective writing area by virtue of the insertion of the plug 604 into the socket 605. It will be appreciated that other shapes of plug and socket arrangements may be utilised dependent upon the application in question.

Figure lid shows a writing tip suitable for use with viscous or thixotropic ink 611 stored in an open ink chamber 612. A hydrophilic plug 608 is held in position in a hydrophilic writing tip 609 by means of a porous, resilient material such as foam rubber 610. When the tip touches the paper, the plug is lifted up allowing ink 611 to flow down from the open ink chamber 612 and produce a line. The same benefits of reduced effective writing area as outlined above with reference to Fig 1 lb are also obtained with this embodiment of the invention.

The present invention also extends to provide the functionality and feel of a fibre-tipped pen by provision of a plurality of narrow conduits. It will be understood that the present invention has been described above purely by way of example and modifications of detail can be made within the scope of the invention. Each feature disclosed in the description, claims and drawings may be provided independently or in any appropriate combination.

It will be also be appreciated that features of one aspect of the invention may be applied to features of another aspect of the invention.

Claims

1. A liquid delivery device comprising a receptacle formed at least in part of hydrophilic material, said receptacle having an internal chamber which opens through a first aperture in the receptacle, wherein, when the chamber is filled or partially filled with liquid and a force acts upon the liquid so that the liquid abuts the first aperture, the device is arranged to provide an adhesive reaction between the liquid and the hydrophilic material of the receptacle, in combination with a surface tension of the liquid at the aperture, to retain the liquid within the receptacle and, when the surface tension is broken, the device is arranged to allow liquid to flow from the chamber through the first aperture under capillary action.

2. A liquid delivery device according to claim 1, wherein the internal chamber is formed of hydrophilic material.

3. A liquid delivery device according to claim 1 or claim 2, wherein the first aperture comprises a narrow conduit.

4. A liquid delivery device comprising a receptacle formed at least in part of hydrophilic material, said receptacle having an internal chamber which opens through a first aperture in the receptacle, wherein, the first aperture comprises a narrow conduit.

5. A liquid delivery device according to claim 3 or claim 4, wherein the first receptacle has a ring of hydrophobic material abutting the first aperture.

6. A liquid delivery device according to any preceding claim, wherein the first aperture is comprised from a cluster of apertures.

7. A liquid delivery device according to claim 6, wherein the cluster of apertures is arranged in a row of apertures.

8. A liquid delivery device according to any preceding claim, further comprising a hydrophilic plug arranged to cooperate with the first aperture to at least partially block the flow of liquid through the first aperture.

9. A liquid delivery device according to claim 8, wherein the hydrophilic plug is arranged to cooperate with the first aperture to form a narrow gap between the plug and the first aperture for the flow of ink.

10. A liquid delivery device according to claim 9, wherein the hydrophilic plug comprises vanes on the side of the plug for engagement with the first aperture.

11. A liquid delivery device according to claim 9 or claim 10, wherein the hydrophilic plug comprises vanes which are formed to delay the flow of ink from the aperture.

12. A liquid delivery device according to claim 8, wherein the hydrophilic plug is arranged to substantially completely block the flow of liquid through the first aperture when the liquid delivery device is in an inactive state and to allow flow of liquid through the first aperture when the liquid delivery device is in an active state.

13. A liquid delivery device according to claim 12, wherein the hydrophilic plug is held in the first aperture by a porous resilient material.

14. A liquid delivery device according to any of claims 8 to 13, wherein the hydrophilic plug has a face which is adapted to smooth ink from the first aperture into a line across a surface to which the ink is to be delivered.

15. A liquid delivery device according to any preceding claim, wherein the receptacle further comprises a writing tip portion, the first aperture being formed through the writing tip portion.

16. A liquid delivery device according to claim 15, wherein the writing tip portion and the receptacle are integrally formed.

17. A liquid delivery device according to claim 15, wherein the writing tip portion is formed separately from, and is conjoined with, the receptacle.

18. A liquid delivery device according to any preceding claim, wherein the receptacle is substantially hollow.

19. A liquid delivery device according to any preceding claim, further comprising a second aperture through which the chamber may be filled with liquid and a closure for sealing the second aperture.

20. A liquid delivery device according to any preceding claim, wherein the receptacle is formed at least in part of clear material.

21. A liquid delivery device according to any preceding claim, wherein the receptacle is formed of biodegradable material.

22. A liquid delivery device according to any preceding claim, further comprising an additional aperture to allow air into the chamber as ink flows out of the chamber.

23. A liquid delivery device according to claim 22, wherein the additional aperture is situated in the writing tip.

24. A liquid delivery device according to claim 22 or claim 23, wherein the additional aperture is recessed in an outer surface of the receptacle.

25. A liquid delivery device according to any preceding claim, wherein an area of the receptacle surrounding the first aperture is shaped to allow smooth delivery of ink.

26. A liquid delivery device according to any preceding claim, wherein the receptacle comprises an indicator on its outer surface indicating optimal orientation of the receptacle.

27. A liquid delivery device according to any of claims 17 to 26, wherein the writing tip comprises an integral collar.

28. A liquid delivery device according to any of claims 17 to 27, wherein the writing tip comprises a long waist to enhance securement of the writing tip within the receptacle.

29. A liquid delivery device according to any preceding claim, wherein the liquid is an ink.

30. A liquid delivery device according to any of claims 1 to 28, wherein the liquid is correctional fluid.

31. A liquid delivery device according to any of claims 1 to 28, wherein the liquid is a glue or other solvent, for use in industrial marking or printing.

32. A pen comprising a barrel formed at least in part of hydrophilic material, said barrel comprising a hollow portion which opens through a first aperture in the barrel, wherein, when the hollow portion is filled or partially filled with ink and a force acts upon the ink so that the ink abuts the first aperture, an adhesive reaction between the ink and the hydrophilic material of the barrel, in combination with the surface tension of the ink at the aperture, retains the ink within the barrel and, when the surface tension is broken, ink flows from the hollow portion through the first aperture under capillary action.

33. A liquid delivery device comprising a receptacle for containing liquid, said receptacle being formed at least in part of a material which has an affinity with the liquid with which it is to be filled and having an internal chamber which opens through a first aperture in the receptacle, wherein, when the chamber is filled or partially filled with liquid and a force acts upon the liquid so that the liquid abuts the first aperture, an adhesive reaction between the liquid and the material of the receptacle, in combination with the surface tension of the liquid at the aperture, retains the liquid within the receptacle and, when the surface tension is broken, liquid flows from the chamber through the first aperture under capillary action.

34. A writing tip for a pen, the writing tip being adapted to engage with a pen barrel wherein the writing tip comprises an aperture arranged to allow the flow of ink from the pen barrel through the aperture under capillary action, and wherein the writing tip further comprises a hydrophilic plug arranged to cooperate with the aperture to at least partially block the flow of liquid through the aperture thereby to provide an effective writing aperture of reduced cross-section.

35. A liquid delivery device, as herein before described with reference to the accompanying drawings.