GB2141072A

GB2141072A - Ink drying apparatus

Info

Publication number: GB2141072A
Application number: GB08410431A
Authority: GB
Inventors: Arthur Roland Palmer; William Kenneth Wright
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-04-21
Filing date: 1984-04-24
Publication date: 1984-12-12
Also published as: GB2141072B; GB8410431D0

Abstract

Apparatus for drying printed ink comprises an emitter of infra-red radiation at a wavelength of between 2.5 mu m and 12.5 mu m. The preferred wavelength emitted is between 3 mu m and 6 mu m, and the infrared emitter is advantageously a ceramic radiation element 4 heated to a temperature between 300 DEG C and 700 DEG C. The apparatus comprises a conveying means 1 for transporting T-shirts and other garments to be printed with ink past the emitter, and the conveying surface is advantageously sloped off each of its opposite longitudinal edges so as to present for example the printed front of the garment closer to the emitter than the unprinted arms of the garment. Uniform curing of the ink is promoted by a fan which circulates air over the printed material. <IMAGE>

Description

SPECIFICATION Ink drying apparatus The present invention relates to an apparatus for drying or "curing" inks which have been printed on to a material, and more particularly to an apparatus for curing inks which have been silk-screened on to a fabric garment such as a T-shirt.

It is well known to dry printed garments and materials by exposing them to heated air.

In general, the air is heated by an electric resistance heating element which emits mainly visible radiation at a wavelength below ilium.

An example of such a heating element is an electric fire.

This method has disadvantages. Firstly, it is expensive in that even a small drying apparatus requires three elements each of three kilowatt power consumption. Secondly, such apparatus carries with it a great danger of scorching of the material and a consequent fire if the material is left too long before the heating element. This may happen if the material is being conveyed before the heating element and the conveying means stops, or if the material is allowed to hang before the heating element unattended. Finally, inks suitable for hot air drying are expensive.

It is an object of the present invention to overcome the above disadvantages and to provide an improved apparatus for drying inks and a method of using such apparatus.

According to a first aspect of the present invention, there is provided an apparatus for drying printed ink comprising an emitter of infra-red radiation at a wavelength of between 2.5 ,um and 12.5 ym.

The preferred wavelength emitted is between 3 ym and 6 jum.

Advantageously the infra-red emitter is a ceramic radiation element, which may be heated to a temperature between 300"C and 700"C.

The element may comprise a set of tiles, each tile having a reflective backing.

The apparatus may further comprise a conveyor means for transporting material printed with ink past the emitter.

The conveyor means may be shaped to present a printed portion of material closer to the emitter than a remaining unprinted portion of the material.

The apparatus may also comprise a fan to circulate air over the material and thereby promote uniform curing of the ink.

According to a second aspect of the present invention there is provided a method of drying printed ink comprising a step of presenting a material printed with the ink within the effective range of an emitter of infra-red radiation.

Preferably the effective range is within 35 to 75 mm.

The method preferably comprises the additional step of transporting the material to a location within the effective range and tran spartig' it from said location.

An embodiment of the invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an end elevation, partially cut away, of an apparatus embodying the invention; and Figure 2 is a side elevation, again partially cut away, of the apparatus.

Referririg now to the drawings, the apparatus comprises a conveyor belt 1, of PTFE coated mesh. This is driven by a single phase drive motor and gearbox 2 with a conventional belt and pulley final drive. The speed of the motor may be varied. The conveyor belt has a sloped surface at each side, which is adapted to accommodate the arms of T-shirts, which are in general not printed, in a folded under condition.

The conveyor belt 1 passes into a drying zone 3, in which is located an array of ceramic radiation elements 4. These have a planar lower surface facing the conveyor belt, and a reflector upper surface. Depending on the temperature to which the tiles are heated, infra-red radiation is emitted at a wavelength generally between 3.0 ,um and 6.0 ym. The wavelength of the emission may be varied by varying the temperature to which the tile is heated. A typical requirement for a small apparatus would be for 3 units each 1.2 kilowatt power consumption.

A low power fan 5 may be provided to move the air across the material being dried and thereby to promote uniform ink curing. It is not necessary to provide a high power fan as it would be if it were necessary to exhaust heated air from the drying zone.

The apparatus may be operated at conveyor belt speeds of between 0.5 and 3.0 inches per second, the tiles are spaced from the surface of the material by a distance of between 35 and 75 mm, and the tiles are heated to a temperature between 300 and 700"C. The temperature may be varied so that the infra-red radiation emitted is of wavelength close to the specific absorption frequency of the printing ink concerned. This produces a very rapid curing and drying of the ink and eliminates any possibility of the printed material charring or scorching.

1. An apparatus for drying printed ink comprising an emitter of infra-red radiation at a wavelength of between 2. 5ym and 1 2. 5jum .

2. An apparatus according to Claim 1 and in which the wavelength emitted is between 3ym and 6ym.

3. An apparatus according to Claim 1 or Claim 2 and in which the infra-red emitter is a ceramic radiation element heated to a temper

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Ink drying apparatus The present invention relates to an apparatus for drying or "curing" inks which have been printed on to a material, and more particularly to an apparatus for curing inks which have been silk-screened on to a fabric garment such as a T-shirt.

It is well known to dry printed garments and materials by exposing them to heated air.

In general, the air is heated by an electric resistance heating element which emits mainly visible radiation at a wavelength below ilium.

An example of such a heating element is an electric fire.

This method has disadvantages. Firstly, it is expensive in that even a small drying apparatus requires three elements each of three kilowatt power consumption. Secondly, such apparatus carries with it a great danger of scorching of the material and a consequent fire if the material is left too long before the heating element. This may happen if the material is being conveyed before the heating element and the conveying means stops, or if the material is allowed to hang before the heating element unattended. Finally, inks suitable for hot air drying are expensive.

It is an object of the present invention to overcome the above disadvantages and to provide an improved apparatus for drying inks and a method of using such apparatus.

According to a first aspect of the present invention, there is provided an apparatus for drying printed ink comprising an emitter of infra-red radiation at a wavelength of between 2.5 ,um and 12.5 ym.

The preferred wavelength emitted is between 3 ym and 6 jum.

Advantageously the infra-red emitter is a ceramic radiation element, which may be heated to a temperature between 300"C and 700"C.

The element may comprise a set of tiles, each tile having a reflective backing.

The apparatus may further comprise a conveyor means for transporting material printed with ink past the emitter.

The conveyor means may be shaped to present a printed portion of material closer to the emitter than a remaining unprinted portion of the material.

The apparatus may also comprise a fan to circulate air over the material and thereby promote uniform curing of the ink.

According to a second aspect of the present invention there is provided a method of drying printed ink comprising a step of presenting a material printed with the ink within the effective range of an emitter of infra-red radiation.

Preferably the effective range is within 35 to 75 mm.

The method preferably comprises the additional step of transporting the material to a location within the effective range and tran spartig' it from said location.

An embodiment of the invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an end elevation, partially cut away, of an apparatus embodying the invention; and Figure 2 is a side elevation, again partially cut away, of the apparatus.

Referririg now to the drawings, the apparatus comprises a conveyor belt 1, of PTFE coated mesh. This is driven by a single phase drive motor and gearbox 2 with a conventional belt and pulley final drive. The speed of the motor may be varied. The conveyor belt has a sloped surface at each side, which is adapted to accommodate the arms of T-shirts, which are in general not printed, in a folded under condition.

The conveyor belt 1 passes into a drying zone 3, in which is located an array of ceramic radiation elements 4. These have a planar lower surface facing the conveyor belt, and a reflector upper surface. Depending on the temperature to which the tiles are heated, infra-red radiation is emitted at a wavelength generally between 3.0 ,um and 6.0 ym. The wavelength of the emission may be varied by varying the temperature to which the tile is heated. A typical requirement for a small apparatus would be for 3 units each 1.2 kilowatt power consumption.

A low power fan 5 may be provided to move the air across the material being dried and thereby to promote uniform ink curing. It is not necessary to provide a high power fan as it would be if it were necessary to exhaust heated air from the drying zone.

The apparatus may be operated at conveyor belt speeds of between 0.5 and 3.0 inches per second, the tiles are spaced from the surface of the material by a distance of between 35 and 75 mm, and the tiles are heated to a temperature between 300 and 700"C. The temperature may be varied so that the infra-red radiation emitted is of wavelength close to the specific absorption frequency of the printing ink concerned. This produces a very rapid curing and drying of the ink and eliminates any possibility of the printed material charring or scorching.

1. An apparatus for drying printed ink comprising an emitter of infra-red radiation at a wavelength of between 2. 5ym and 1 2. 5jum .

2. An apparatus according to Claim 1 and in which the wavelength emitted is between 3ym and 6ym.

3. An apparatus according to Claim 1 or Claim 2 and in which the infra-red emitter is a ceramic radiation element heated to a temper ature between 300"C and 700"C in use.

4. An apparatus according to Claim 3 in which the element comprises a set of tiles each having a reflective backing.

5. An apparatus according to any preceding Claim, and comprising a conveying means for transporting material printed with ink past the emitter, and characterised in that the conveying surface slopes off along each of its opposite longitudinal edges in such a way that a printed portion of material carried by the conveyor can be transported closer to the emitter than a remaining unprinted portion of material supported by the or each sloped-off portion of the conveying surface.

7. An apparatus according to any of the preceding Claims and with a fan to circulate air over the material in order to promote uniform curing of the ink.

8. An apparatus in accordance with any of the preceding Claims and characterised in that the infra-red radiation emitted is of wavelength close to the specific absorption frequency of the printing ink concerned.

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

10. A method of drying printed ink comprising a step of presenting a material printed with the ink within the effective range of an emitter of infra-red radiation.

11. A method according to Claim 10 with the effective range within the distance 35mm to 75mm from the emitting surface.

1 2. A method substantially as described herein with reference to the accompanying drawings.