Improved apparatus for liquid colour deposition

Abstract

 @ An apparatus for depositing predetemined volumes of liquid colour onto a substrate including at least one dispensing pump 11 connected between a respective container for liquid colour to be deposited and a respective deposition orifice, characterised in that the pump is actuator by means of a remove actuator 24. The remove actuator comprises a piston rod 29 which moves, under the influence of pneumatic pressure, against a pivoted actuator arm 32. The end of the arm remote from the actuator 24 acts against a collar 23 on a combined piston rod and outlet tube 22 of the pump 11, causing liquid colour to be discharged from the pump. The volume swept by the piston of the pump may be varied by varying the position of the actuator piston rod 29 with respect to the actuator arm 32.
Liquid colour may be supplied to the dispensing pumps from a flexible container provided with an external agitator and an outlet spout.

Description

[0001] The present invention relates to apparatus for the deposition of a predetermined volume of liquid colour onto a substrate.

[0002] The invention is particularly useful in the printing of colour cards, showing samples of paint, cosmetics and the like, and in other applications in which it is desired to print a matrix of coloured areas on a substrate, often of card or plastic. One form of colour deposition apparatus is described in our United Kingdom patent application number 80 39811, published as GB2065559A, but suffers from the disadvantage that the volume of colour metered out during the stroke of the pump is the same for all pumps connected to a common source of fluid pressure. The volume may only be adjusted by adjustment of the actuating pressure. Thus, in a case in which several areas of colour of different sizes are to be printed, several sources of pressure, at different pressures, must be provided.

[0003] According to the invention, there is provided an apparatus for depositing predetermined volumes of liquid colour onto a substrate, comprising at least one pump comprising a cylinder, a pump piston movable therein and an inlet connected to a respective container for liquid colour and an outlet connected to a respective deposition orifice characterised in that a pivoted connecting arm extends between the pump and a remote actuator, the actuator comprising a cylinder connected to a source of fluid pressure and an actuator piston movable therein, the actuator piston operating to bear upon a preselected portion of the connecting arm whereby the arm operates to move the pump piston to cause liquid colour to pass out of the pump.

[0004] A second aspect of the invention provides an apparatus for depositing discrete volumes of liquid colour comprising at least one pump, characterised in that the pump is connected between a respective flexible container for liquid colour, having an external agitator and an outlet, and a respective deposition orifice, the outlet from the container comprising a spout, one end of which is retained inside the container and the other end of which is connected to the inlet of the pump, and a filter contained in the spout, whereby liquid is filtered on leaving the container.

[0005] The invention will be further described, by way of example, with reference to the drawings in which:

Fig. 1 shows an actuator and pump assembly according to one aspect of the invention, the actuator assembly being shown in section;

Fig. 2 shows an alternative actuator and pump assembly according to one aspect of the invention, the actuator assembly being shown in section;

Fig. 3 shows the pump of Figs 1 and 2 in section;

Fig. 4 shows an alternative pump for use with the actuator of Figs 1 and 2; and

Fig. 5 shows a flexible container according to another aspect of the invention.

[0006] In the actuator and pump assembly shown in Figs 1 and 2, the pump 11 is provided at its upper end with a liquid colour feed pipe 12 and at its lower end with a liquid colour discharge pipe 13, connected to a deposition matrix (not shown) such as that shown in GB 2065559A.

[0007] The pump 11 is held in a bracket 14, between two abutments 15 and 16. Advantageously, the pump is constructed of a relatively low cost material, such as a plastic material, so that the pump may be discarded at the end of a run of a particular colour of lacquer, by detachment of the liquid colour feed and discharge pipes 12 and 13 and removal of the pump 11 from the bracket 14.

[0008] As shown in Fig. 3, the pump 11 comprises an upper cylindrical body portion 17, defining a pump chamber 18 and threadedly secured to the upper cylindrical body portion 17 is a lower cylindrical body portion 19. The pump chamber 18 houses a pump piston 20 and a spring 21 bearing at one end on the upper end wall of the pump body 17 and at the other on the pump piston 20. The pump piston is connected to a combined piston rod and outlet pipe 22, which passes through an aperture in the lower cylindrical body portion 19, and is connected to the liquid colour discharge pipe 13. The combined piston rod and outlet tube 22 is press fitted into a collar 23 of brass or plastic, for example, external to the pump 11, for co-operation with the actuator assembly.

[0009] The piston 20 has an aperture 37, through which liquid colour can pass into the combined piston rod and outlet tube 22. The aperture 37 is provided with a ball valve 39 to close the aperture 37 when the pump chamber 18 is being recharged with the liquid colour. The closed end of the pump chamber 18 is provided with an inlet for liquid colour, supplied by a feed pipe 12, and provided with a ball valve 38 to prevent liquid colour returning into the feed pipe when the pump is operated.

[0010] Fig. 4 shows an alternative pump for use in the invention. Elements of the pump common to Figs. 3 and 4 are indicated by common reference numerals. The arrangement of this pump is similar to that of the pump of Fig. 3. However, the piston 20, with its aperture 37, and combined piston rod and outlet pipe 22 are formed in one piece. The end of the outlet pipe 22 is seated in the collar 23, which has an extension 23a to receive the discharge pipe 13. The ball valve 39, to prevent liquid colour from passing into the discharge pipe 13 when the pump chamber 18 is being recharged, is located with the collar 23, at the end of the outlet tube 22.

[0011] As shown in Fig. 1, the actuator 24 comprises a housing 25 defining a chamber 26 provided with a fluid pressure inlet pipe 27 having a threaded outer surface. This is attached to a source of fluid pressure by a pipe 36. The actuator chamber 26 houses flexible bellows 28, which are attached to a piston rod 29. The actuator 24 is attached to the bracket 14 holding the pump 11 by means of the pressure inlet pipe 27 which protrudes up through a slot 30 running the length of the bracket 14, and is held in place by a nut 31. An actuator arm 32 is pivotally attached to the bracket, and extends between the collar 23 on the combined piston rod and outlet tube 22 of the pump 11 at one end and the actuator piston rod 29 at the other. The actuator piston rod 29 is provided with a lug 34 on its lower surface which is selectively located in one of several holes 35 in the actuator arm 32.

[0012] In use, compressed air, or other fluid pressure, is applied to actuator chamber 26, through the pipe 36 and the pressure inlet 27. The compressed air source is operated by, for example, a machine cam, not shown. The pressure in the actuator chamber 26 acts on the bellows 28, causing them to move the actuator piston rod 29 against the actuator arm 32. The portion of the arm 32 acted upon by the piston rod 29 moves downwards about the pivot 33, causing the end of the arm connected to the collar 23 of the pump 11 to move upwards. This moves the collar 23, and thus the combined piston rod and outlet tube 22, upwards, in turn causing the pump piston 20 (Fig 3) to sweep the- pump chamber 18. Liquid colour contained in the pump chamber 18 is forced from the pump chamber through an aperture 37 in the pump piston 20 into the outlet tube 22 and so into the discharge pipe 13. Colour is prevented from returning to the feed pipe 12 by the ball valve 38. When the pneumatic pressure in the actuator chamber 26 is removed, the spring 21 causes the pump piston 20 to return to its former position, drawing new liquid colour into the pump chamber 18 through the feed pipe 12. The aperture 37 in the pump piston 20 is closed at this stage by the other ball valve 39. The combined piston and outlet tube 22, the actuator arm 32 and the actuator piston 29 also return to their former positions.

[0013] By adjustment of the position of the actuator 24 on the bracket l4, the distance moved by the actuator arm may be adjusted. Thus, the volume swept by the pump piston 20, and so the volume of liquid colour deposited may be adjusted. This adjustment may be made individually to each of several pump and actuator assemblies connected to the same fluid pressure source, removing the need for several different sources of fluid pressure at different pressures. Thus, a deposition matrix containing cells of several different sizes may be fed from an array of pumps, normally six, all of which may be connected to a common source of pressure, each cell receiving the correct volume of liquid colour.

[0014] Fig 2 shows a second embodiment of an actuator according to the invention.Elements of the pump and actuator common to Figs 1 and 2 are indicated by the same reference numerals. In this embodiment, the actuator assembly 24. comprises an open ended cylindrical housing 50 which is secured to a cap 51 extending from the pressure inlet pipe 27 to define the actuactor chamber 26. A piston 52 inside the cylindrical housing 50 has a moulded synthetic rubber seal 53 extending over the upper face of the.piston 52 and around the sides of the piston, between it and the housing 50. The seal 53 is located on the piston 52 by a lug 54 extending from the upper surface of the piston through the seal 53. A piston rod 29 is attached at its upper end to the piston 20, and located at its lower end on the actuator arm 32 as described earlier with reference to Fig 1.

[0015] This actuator operates in a similar manner to the actuator of Fig 1. Compressed air, or other fluid pressure, is applied to the chamber 26 through the pipe 36 and the pressure inlet 27. Again, the compressed air source is operated by a machine cam, for example, not shown. The pressure in the actuator chamber 26 acts on the piston 52, causing it to move the piston rod 29 against the actuator arm 32. The actuator arm acts on the collar 23 of the pump 11 in the manner described earlier.

[0016] _Fig 5 shows a fJexible container 40 for the liquid colour which communicates with the pump of Figs 1 and 2 by way of the liquid colour feed pipe 12. The container 40 is preferably made from a transparent or translucent plastics materials such as nylon; nylon is preferred because of its good vapour barrier properties.

[0017] The lower end of the flexible container 40 is sealed off by a metal clip 47. Adjacent to this, the feed pipe 12 is connected to the flexible container 40 by means of a spout 41. The spout comprises a main, cylindrical portion 42, to which is attached the feed pipe 12. The main portion 42 extends into the flexible container 40 and is secured there by a cap portion 43, which is threadedly engaged with the main portion 42 of the spout 41. A portion of the wall of the flexible container is trapped between the threads of the two portions of the spout 41, securing it in position. The cap portion 43 is provided with an aperture for the flow of liquid colour defined by a wall 44 extending into the spout 41. A substantially conical filter 45 of, for example 200µm mesh nylon gauze, is secured, inside the spout 41, to the wall 44 by an O-ring 46. Thus, liquid colour leaving the flexible container passes through the filter 45 before entering the pumps 11.

[0018] Advantageously, for economy of manufacture, the main spout portions 42 may be identical to the upper cylindrical pump portions 17, and the cap portions 43 identical to the lower cylindrical pump portions 19.

[0019] The container is tilled with liquid colour at the upper end, which is then sealed with a metal clip 48. The metal clips 47 and 48 used to seal the lower and upper ends of the containers 40 may be dispensed from a hand held gun.

[0020] The container is also provided with an agitation sleeve 49 of plastics material which agitates the contents as it is inflated and deflated pneumatically. Both the inflated and deflated positions are shown in Fig 4. As the liquid colour is sealed in the container immediately after charging, the possibility of deterioration and contamination is greatly reduced. The preferred transparent containers allow a visual check on the level and quality of the contents.

[0021] Several containers may be arranged in a row on an inclined bench, and agitated by a common inflatable sleeve laid between the containers and a stop bar above the containers, or by a rod laid across the containers and periodically raised and lowered. Alternatively, the containers may be provided with an internal agitator, such as a plastic ball. In this case, the containers may be stored hanging from racks which may be tilted to agitate the containers contents.

Claims

1. An apparatus for depositing predetermined volumes of liquid colour onto a substrate, comprising at least one pump comprising a cylinder, a pump piston movable therein and an inlet connected to a respective container for liquid colour and an outlet connected to a respective deposition orifice characterised in that a pivoted connecting arm extends between the pump and a remote actuator, the actuator comprising a cylinder connected to a source. of fluid pressure and an actuator piston movable therein, the actuator piston operating to bear upon a preselected portion of the connecting arm whereby the arm operates to move the pump piston to cause liquid colour to pass out of the pump.

2. An apparatus according to claim 1 comprising a plurality of pumps and a plurality of respective actuators connected to the pumps, the fluid pressure source being common to each actuator.

3. An apparatus according to claim 1 or 2 in which the or each pump piston is biased by a spring inside the or each pump cylinder.

4. An apparatus according to any previous claim in which the container for liquid colour is a flexible container provided with an external agitator and an outlet for liquid colour.

5. An apparatus according to claim 4 in which the outlet for liquid colour from the flexible container comprises a spout one end of which is retained inside the container and the other end of which is connected to the inlet of the pump.

6. An apparatus according to claim 5 in which the spout contains a filter, whereby liquid colour is filtered on leaving the container.

7. An apparatus according to claim 4, 5 or 6 in which the external agitator comprises a sleeve extending around the flexible container, the sleeve being inflatable under fluid pressure.

8. An apparatus for depositing discrete volumes of liquid colour comprising at least one pump characterised in that the pump is connected between a respective flexible container for liquid colour, having an external agitator and an outlet, and a respective deposition orifice, the outlet from the container comprising a spout one end of which is retained inside the container and the other end of which is connected to the inlet of the pump, and a filter contained in the spout, whereby liquid is filtered on leaving the container.

9. An apparatus according to claim 7 in which the external agitator comprises a sleeve extending around the flexible container, the sleeve being inflatable under fluid pressure.

Drawing