GB2359503A - Spray apparatus for in-flight mixing of colourants - Google Patents

Abstract

An apparatus, such as an airbrush, for mixing and dispensing colourant e.g. paint or ink. One or more colours are selectively introduced from a plurality of reservoirs (3, 4, 5) to corresponding outlet conduits (33, 34, 35) and thereafter to one or more individually controllable air streams by the venturi effect. Mixing of the colours occurs in flight to produce different colours or shades. Capillary action may be used to retain the colourants in their reservoirs or a baffle may be incorporated. Absorbent material may be incorporated in the outlet conduits to retain the colourant and to draw colourant to the exit aperture by capillary action.

Description

1 Multiple shade airbrush 2359503 The present invention relates to an

apparatus for drawing, writing or shading, by the process of spraying colorant and provides individual colours or simultaneously combined colours, which form shades. This is achieved by introducing individual colours simultaneously to one or more controllable high velocity air streams, which are positioned to ensure the colours are mixed in flight, prior to contacting the desired surface, which could, though not io exclusively, be paper.

In its present embodiment one may liken the apparatus to an airbrush.

Airbrushes have been around for many years and operate in various ways.

A common technique used by airbrush manufacturers to produce a fine spray is to atomise fluid by drawing it up from a reservoir through a small tube and passing high velocity air over the end of the tube, known as the venturi effect. The fine liquid particles are dispensed on to the desired surface in a thin layer to form a coloured coating.

Airbrushes commonly have a reservoir containing colorant; hanging below or protruding above a pen like structure. This extra mass requires that the operator have a high degree of control in order to control the destination of the colorant.

Cheap airbrushes provide a simple on 1 off air valve, which makes it difficult to control the volume dispensed and can lead to over spraying. More expensive models provide more control over flow but a high degree of skill is still required to operate them, because of the complexity of the valves.

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0 2 To change colours it is a requirement that a conventional airbrush be dismantled and cleaned with water or solvent prior to introducing a different colour or shade, which can then be dispensed as described previously.

To create shades using a conventional airbrush, different colours are mixed externally by hand to produce the desired shade then placed in the freshly cleaned reservoir before finally being dispensed on to the desired surface.

io Alternatively a shade may be produced by lightly spraying one colour over an existing colour, in much the same way a colour printer produces a shade, however this requires great skill to produce the desired shade.

The combination of issues relating to user skill, mess and cost frequently 15 discourage the use of airbrushes by children and indeed many adults.

It is an object of the present invention to address some of the aforementioned disadvantages associated with conventional airbrushes.

More especially it is an object of the present invention to provide means to produce single colours or complex shades by way of a simple arrangement that will allow the'user to select an individual colour or shade with ease and without the need to repeatedly change or clean reservoirs.

In the embodiment described hereafter, the venturi effect is employed to introduce colorant to high velocity air streams, prior to said air streams mixing colours in flight to produce a desired shade, however other methods may be employed to introduce colorant to said air streams, we may for example use piezo electric devices.

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4 1 w - 3 An embodiment of the invention will now be described by way of example with the aid of accompanying drawings.

Figure 1) depicts a general assembly in all elevations and makes reference to the following figures 2 to 5. Figure 2) depicts a sectioned elevation viewed from the side. Figure 3) depicts a top view general assembly. Figure 4) depicts a sectioned elevation viewed from above.

io Figure 5) depicts a top elevation of the air supply hole and shows clearly how the shade valve works.

According to the present invention there is provided an apparatus, which is elongated to form a similar geometric shape as an ordinary pen (fig 2) (1). The apparatus has formed within its length elongated multiple reservoirs (fig 2) (2) and (fig 4) (3,4,5), which contain the primary colours from which most shades can be achieved.

In this embodiment three reservoirs (fig 4) (3,4,5) are used however any number of reservoirs and colours could be incorporated in order to achieve more subtle shades.

According to the present invention each reservoir has a fine tube or ink nozzle protruding the front of the apparatus (fig 2) (6) and (fig 3) (16, 17,18). Accordingly there is perpendicular to each ink nozzle a high velocity air nozzle (fig 2) (7) and (fig 5) (13,14,15). Individual colours are produced in the form of a fine spray by passing high velocity air over individual ink nozzles. Passing high velocity air over two or more ink nozzles simultaneously and in varying ratios produces a shade (fig 5) (8).

According to the present invention an air supply is provided by some means through a hole running down the length of the apparatus (fig 5) (9) terminat ing at a shade valve (fig 5) (10) and (fig 2) (12).

4 The shade valve (fig 5) (10) can be rotated (fig 5) (11) to allow the air supply to pass through one or more of the air nozzles (fig 2) (7) and (fig 5) (13,14,15), which are placed perpendicular to the individual ink nozzles (fig 2) (6) and (fig 3) (16,17,18).

According to the present invention rotating the shade valve can partially or completely cover any combination of the inlets (fig 2) (19) to the air nozzles (fig 2) (7) allowing full, partial or zero air pressure from the supply source, io through any one or more of the aforementioned air nozzles. This in turn controls the proportion of ink atomised from the ink reservoirs (fig 4) (3,4,5) and in turn whether the final output will be a single colour or combined shade.

In this embodiment the shade valve (fig 2) (12) rotates, however this valve might take another form for example a linear slide valve or indeed piezo electric valves.

According to the present invention there is placed an air valve (fig 2) (22) and (fig 5) (36) communicating perpendicular to the air supply hole (fig 2) (23).

When said air valve is uncovered, the supplied air (fig 2) (23) escapes preferentially through the air valve (fig 2) (22) preventing high velocity air from passing over the ink nozzles (fig 2) (6) and (fig 3) (16,17,18) and subsequently the dispensation of colorant from the apparatus.

There is provided a trigger mechanism (fig 2) (20), which includes a compliant valve seat (fig 2) (21). The valve seat communicates fully or partially with the air valve (fig2) (22) and (fig 5) (36), depending on how firmly the trigger mechanism (fig 2) (20) is depressed. Covering or partly covering the air valve re-directs the airflow at full or partial pressure forward (fig 5) (9) to one or more of the air nozzles (fig 2) (7) and (fig 5) (13,14,15), dependant on the position of the shade valve (fig 5) (11).

2 1 Advantageously the trigger mechanism with its compliant valve seat provides fine control over the density of the final spray.

According to the present invention there is provided means for introducing colorant to each reservoir via inlet ports (fig 4) (24,25,26) located at the rear of the apparatus. Colorant is introduced through the appropriate inlet port via some means and passes in to a corresponding main reservoir via rear io connecting ports (fig 4) (27,28,29). Once the corresponding reservoir is filled to an appropriate level, any excess fluid remaining in the inlet port is drawn fully in to the main reservoir via capillary action and is retained within.

Advantageously the diameter of the rear connecting ports (fig 4) (27,28, 29) can be set to prevent liquid from reversing back through the connected inlet ports (fig 4) (24,25,26), due to the strength of capillary action thus preventing leaking from the main reservoir.

According to the present invention there are provided features (fig 4) (30,31,32), which contain sponge like absorbent material. This material is packed to a specific density such that colorant is drawn from a corresponding main reservoir (fig 4) (3,4,5) via front connecting ports (fig 4) (33,34, 35) and held preferentially within the structure. These features advantageously provide the apparatus with two main attributes.

1) When the apparatus is pointed down gravity would normally force the colorant to drip causing a mess. The pore size of the sponge like structure is smaller than the diameter of the final ink nozzle. The pore diameter of the sponge like material is controlled by how tightly it is packed within the features (fig 4) (30,31,32). The packing can be optimised such that capillary action is strong enough to pull colorant from corresponding ink nozzles (fig 3) (16,17,18), back toward its structure.

6 Advantageously the absorbent material holds the fluid in position when the apparatus is pointing down preventing dripping from the ink nozzles.

2) When the apparatus is pointed vertically to an undesired angle the absorbent material allows colorant to be dispensed for a period of time, which is defined by the density of packing of the absorbent material. As one points the apparatus above horizontal the colorant in the main reservoirs (fig 4) (3,4,5) moves to the back of the apparatus and is no longer in communication with the front connecting ports (fig 4) (33,34, 35). This means that colorant dispensed is limited to the volume held in the sponge like material.

Advantageously each of these features may be regarded as time control 15 switches.

Advantageously these switches also prevent the user from spraying colorant on to undesired surfaces, such as ones face for example.

According to the present invention there is also provision within the embodiment to prevent spillage when the apparatus is shaken. The main reservoirs (fig 4) (3,4,5) are narrow, accordingly surface tension is sufficiently strong that the colorant is held preferentially within each reservoir such that when the apparatus is shaken colorant does not violently move from one end 25 of the apparatus to the other, which would cause leaking.

Advantageously there is also provision within the embodiment to add extra baffling within each reservoir to further control the position of the colorant.

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Claims (15)

Claims

1) An apparatus for mixing and dispensing colorant in the form of a fine spray, providing means to introduce one or more colours from multiple reservoirs, to one or more individually or simultaneously addressable and controllable air streams, thereafter mixing said colours in flight, to produce individual colours or combined shades.

2) An apparatus according to claim 1 whereby colorant is introduced to individually or simultaneously addressable and controllable air streams by any means.

3) An apparatus according to claim 2, which incorporates multiple colorant reservoirs.

4) An apparatus according to claim 3 whereby colorant reservoirs can be addressed individually or simultaneously.

An apparatus according to claim 4 whereby colorant is introduced to simultaneously or individually addressable and controllable air streams by venturi effect.

6) An apparatus according to all previous claims whereby there is provided some means to control air flow and air pressure for individually or simultaneously addressable air nozzles.

An apparatus according to claim 6 whereby the air nozzles are positioned such that if more than one air nozzle is activated the introduced colorant is mixed in flight.

8) An apparatus according to claim 7 whereby control of air flow and air pressure for individually or simultaneously addressable air nozzles takes the form of a rotating valve.

9) An apparatus according to all previous claims whereby capillary action is used to retain colorant within each reservoir.

10) An apparatus according to claim 9 whereby capillary action is used to prevent dripping from the ink nozzles.

8 11) An apparatus according to claim 10 whereby capillary action from absorbent material is used to preferentially retain or dispense colorant for a pre-defined time.

12) An apparatus according to claim 11 whereby the geometry of the ink reservoir encourages surface tension to hold the liquid contained preferentially, such that leaking does not occur when the apparatus is shaken.

13) An apparatus according to claim 12 whereby baffles are incorporated in to the reservoirs to prevent liquid from moving undesirably and subsequently leaking.

14) An apparatus according to all previous claims, whereby air pressure and air flow for all incorporated air nozzles are controlled overall by a single compliant valve.

15) An apparatus substantially described herein with reference to and as illustrated in the accompanying drawings.

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