UV LAMP

The present invention relates to a UV lamp. More especially the invention relates to a UV lamp for use with ink curing apparatus used commonly in the printing industry.

Lamps used in ink curing apparatus generally comprise a glass tube with an electrode extending into each end of the lamp tube. Each end of the tube is pinch sealed and received within a ceramic block into which the free end of each electrode also extends. A wire extends out of the ceramic block for connection to the electricity supply to power the lamp.

The ceramic blocks are constructed in a variety of shapes and sizes to fit the lamp casing of the curing machine in which the lamp is designed to be used.

UV lamps for use in ink curing machines are run at high intensities and consequently have a limited life span before needing replacement. The entire lamp structure, including the glass tube, electrodes, wires and ceramic blocks need to be replaced. Although disposal of the lamp tube is strictly regulated (as it contains chemical compounds such as mercury), the ceramic caps and electrical connectors are often simply thrown away with normal rubbish. Each lamp (one of many) commonly needs to be replaced twice a year. The problem resides in the amount of waste material that quickly builds up because of the vast number of lamps being used at any one time in the industry.

In use, the lamp is held within a reflector housing. The reflector heats up during use and expands, which causes movement of the reflector. If the connection between the lamp and the reflector housing is rigid the connection will be broken by the movement of the reflector.

The present invention seeks to alleviate the aforementioned disadvantages with known UV lamps by providing an "environmentally friendly" lamp that has little waste material, once spent. The lamp construction is simplified to provide considerable cost benefits in both manufacture and disposal. Furthermore, the lamp configuration is improved to allow for expansion of the reflector housing, in which the lamp sits, during use.

In one aspect of the present invention there is provided a lamp housing for an ink curing machine, the housing comprising at least one ceramic holding means configured to receive an end of a lamp wherein the or each ceramic holding means comprises means to connect the lamp end to a power supply.

Preferably, the at least one ceramic holding means are removeable from the lamp.

By allowing the ceramic holding means to be removed from the lamp, the lamp can be simply and easily disposed of without also requiring disposal of the ceramic components. This reduces operating costs and reduces the volume of waste created.

Preferably, the or each ceramic holding means further comprises a resilient contact means.

Resilient contact means allow movement of the lamp within the ceramic holding means. This allows for a secure connection to be maintained between the holding means and the lamp even if lamp movement is caused by expansion of the apparatus during printing.

More preferably, each ceramic holding means comprises a hollow ceramic frame with a first resilient contact means attached thereto and a

ceramic lid member with a second resilient contact means attached thereto, wherein the first and second resilient contact means are configured to engage each other.

In a second aspect of the present invention, there is provided a lamp for use with ink curing apparatus, the lamp comprising a cylindrical tube sealed at both ends and an electrical connector extending into each end of the tube, through the seal, wherein the distal end of each electrical connector is uncovered.

By "uncovered" it is meant that the distal end of each electrical connector is open to the atmosphere and is not covered by any housing, such as a ceramic header, for example.

One embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of part of a lamp constructed in accordance with the present invention; and

Figure 2 is a schematic illustration of how the lamp of Figure 1 would be installed within a lamp housing of, for example, ink curing apparatus; and

Figure 3 is cross-sectional view of a lamp end constructed in accordance with a further embodiment of the present invention;

Figure 4 is a schematic view of part of a lamp constructed in accordance with a second embodiment of the present invention;

Figure 5 is an enlarged view of the area marked A of the electrical connector of the lamp of Figure 4; and

Figure 6 is a cross-sectional view of a ceramic end cap constructed in accordance with the second embodiment of the present invention.

Referring first to Figure 1, a lamp 10 for use with, for example, ink curing apparatus, comprises a hollow tubular main body 12 made, for example, of glass. The main body 12 has located therein chemical compounds to provide ultra violet (UV) heat when an electrical source is applied to the lamp 10.

Each end 14 of the lamp 10 (only one end is shown in Figure 1), is formed with a pinch seal 16. An electrode 18 extends into the end of the main body 12. The other end of the electrode 18 is connected to an electrical connector 20 which extends through the pinch seal 16 and out of the end 14 of the lamp 10.

The end 22 of the electrical connector 20 protrudes from the end of lamp 10 and is uncovered. As can be seen in Figure 2, this allows the connector end 20 to be inserted into a connector housing 24 forming part of a lamp housing 28 located within the ink curing apparatus.

When the lamp 10 is spent, the lamp 10 is removed by simply disengaging the electrical connector end 22 from the connector housing 24 of the lamp housing 26 and removing the lamp 10 from the apparatus.

The absence of any ceramic caps, or wires formed as part of the lamp 10 allows the entire lamp 10 to then be simply and easily disposed of in accordance with industry regulations.

Figure 2 shows the how one end of the lamp 10 is connected to the connector housing 24. The connector housing 24 comprises a ceramic cap 26 fixed to a frame of the lamp housing 28. The ceramic cap 24 is

typically fixed to the frame 28 using capped fixings 30 filled with ceramic cement.

The ceramic cap 26 has a recess 32 in its end surface to receive the end 14 of the lamp 10. The cap 26 is secured by fixings 40 around the lamp end 14. A sprung loaded block 34, or other suitable loaded connection, having a metal contact 36 is located at one end of the recess 32. The metal contact 36 is connected to a lamp cable 38 which extends out of the connector housing 24 to a power supply.

The lamp 10 is installed into the lamp housing 28 by inserting the lamp end 14 into the recess 32 of the cap 26 in such a way that the end 22 of the electrical connector 20 engages with the metal contact 36.

The electrical connection takes place entirely within the ceramic cap 26 for heat absorption.

Referring now to Figure 3, the end 14 of the lamp 10 may be pinched to form a specific shape construction in cross section. The recess 32 of the cap 26 would be formed as a complimentary shape to the lamp end 14. This would allow for better retention of the lamp end 14 within the cap 26 and would also provide an identifiable feature of the lamp 10 to help distinguish lamps of differing properties.

Figure 3 illustrates only one example of the pinch shape. It is clearly envisage that the pinch could provide a lamp end 14 of any shape, for example that of an "S".

Referring to Figure 4, in a second embodiment of the present invention, the lamp 10 comprises a hollow tubular main body 12 each end of which is formed with a pinch seal 16. An electrode extends into the end of the main body 12 and is connected to an electrical connector 20 which

extends through the pinch seal and out of the end 14 of the lamp 10. As shown in Figure 5, the end of the electrical connector 22 comprises two pins which are soldered to the lamp end 14 and are uncovered and exposed.

Referring to Figure 6, in the second embodiment of the present invention, a lamp connector housing 24' comprises a hollow ceramic frame 40 to which is attached a metal contact 42. The metal contact 42 comprises a first resilient metal clip, which may be made of copper or any other suitable material. The metal contact 42 is connected to a lamp cable 38; known as a HT wire, which extends out of the frame 40 to a power supply. The first resilient metal clip 42 is configured to mate with and receive a second resilient metal clip 44 made of an identical or similar material. The second resilient clip 44 is connected to a ceramic head or lid 46.

In use, the lamp end 14 sits within the hollow ceramic frame 40 and makes contact with the first metal clip 42. The second metal clip 44 is pushed over the lamp 10 and mates with the first metal clip 42. The second metal clip sits 44 inside the first metal clip 42 so that a contact is formed. The ceramic head 46 is then held against the hollow ceramic frame 40 to completely enclose the lamp end 14. The electrical connection takes place entirely within the ceramic cap 40, 46 for heat absorption.

During printing, the ceramic frame 40, 46 sits within a reflector housing (not shown). As the reflector housing heats up, it expands in length, parallel to the longitudinal axis of the lamp. The first and second mating clips 42, 44 are resilient and will move outwardly away from the lamp to allow movement of the lamp 10 and its connectors 22 with the longitudinal movement of the reflector housing. The ceramic frame 40, 46 securely holds the lamp and maintains good electrical contact between the lamp end and the power supply during any expansion.

When the lamp 10, is spent, the lamp is removed by disengaging the two mating metal clips 42, 44 and thereby separating the ceramic head 46 from the ceramic frame 40. As discussed with respect to the first embodiment, there are no ceramic components or wires formed a as part of the lamp 10 and the entire lamp can be simply and easily disposed of. The ceramic end cap 24' can then be re-used with a new lamp 10.

It will be appreciated that the foregoing is merely exemplary of the lamp and end cap of the present invention. The skilled reader will understand that modifications can readily be made thereto without departing from the true scope of the invention.