This application claims benefit of Italian patent application number 102017000118834, filed Oct. 20, 2017 which is herein incorporated by reference.
The present invention relates in general to textile printers for digital printing on fabrics.
More particularly, the invention relates to a heated roller, designed in particular to be used in a textile printer.
In digital printing on fabrics, thermosetting of the inks on the fabric may be necessary. In these cases, it is common to use a thermosetting unit comprising a plurality of rollers through which the fabric is passed downstream of the printing unit. The thermosetting unit can be an integral part of the textile printer (in-line thermosetting) or it can be a separate apparatus with respect to the textile printer. The thermosetting unit can be provided with at least one heated roller, having an outer surface heated to temperatures that can reach up to 200° C.
The heating of a roller can be obtained by means of a heating circuit using a diathermic fluid circulating inside the heated roller. Heated rollers comprising infrared lamps as heating elements are also common.
The heating of the rollers by means of infrared lamps offers considerable advantages with respect to heating systems using diathermic fluids, especially in that they do not require a circuit for heating and circulation of the diathermic fluid inside the roller.
An infrared lamp for heating a heated roller generally comprises a quartz crystal body in which an electrical resistance is inserted which emits infrared light. The infrared lamp extends along the entire length of the heated roller and is supported at its ends outside the heated roller. The infrared lamp reaches temperatures on the surface of the quartz crystal body that can exceed 700° C. The quartz crystal also becomes less rigid at these temperatures. The infrared lamp, being supported only at its ends, can bend under the action of its own weight.
A limitation of heating systems with heated rollers using infrared lamps is that when the lamp has a length greater than 2 m it tends to bend and the bending of the lamp may cause it to break.
The present invention aims to provide a heated roller that overcomes the problems of the prior art.
According to the present invention, this object is achieved by a heated roller having the characteristics disclosed herein.
The claims form an integral part of the disclosure provided here in relation to the invention.
The present invention will now be described in detail with reference to the attached drawings, given purely by way of non-limiting example, wherein:
It will be appreciated that, for clarity and simplicity of illustration, the various figures may not be reproduced on the same scale.
With reference to
In the illustrated embodiment, the textile printer 10 comprises a thermosetting assembly 18 for thermosetting the inks onto the fabric. The thermosetting assembly 18 comprises a heated roller 20, shown in an exploded position in the representation of
With reference to
As illustrated in greater detail in
With reference to
During operation, the infrared lamp 38 reaches very high operating temperatures (close to 700° C.). The infrared lamp 38 may be very long, for example, greater than 2 m. Considering the high length and the high operating temperature, the part of the infrared lamp 38 included between the two stationary supports 22′, 22″ is subjected to bending, which could cause the lamp to break.
To overcome this problem, the heated roller 24 comprises a lamp support device 42 which extends between the stationary supports 22′, 22″ within the tubular element 24, and which supports the portion of the infrared lamp 38 located inside the tubular element 24. In this way, the infrared lamp 38, instead of being supported only at its ends 38′, 38″, is also sustained and supported in the portion that extends inside the tubular element 24.
During operation, the lamp support device 42 undergoes thermal expansion due to the high temperature produced by the infrared lamp 38. The lamp support device 42 would therefore tend to bend inside the tubular element 24. In order to avoid bending of the lamp support device 42 due to thermal expansion, the heated roller 20 comprises an elastic device 44 which applies an elastic tension to the lamp support device 42, which acts between the stationary supports 22′, 22″ in the direction of the longitudinal axis A. The elastic tensioning of the lamp support device 42 ensures the absence of bending of the lamp support device 42 due to thermal expansion. In fact, the increase in length of the lamp support device 42 due to the temperature increase is recovered by the elastic device. In this way, the lamp support device 42 remains without deformations even at the high operating temperatures of the infrared lamp 38. Consequently, the infrared lamp 38 can be supported inside the tubular element 24, and bending of the infrared lamp 38 and the consequent risks of breakage are avoided.
A possible embodiment of the lamp support device 42 and of the elastic device 44 will be described below. It is understood that the embodiment described constitutes only one of the possible embodiments of the present invention. The lamp support device 42 and the elastic device 44 which applies the elastic tensioning to the lamp support device 42 may vary with respect to the embodiment shown in the figures without departing from the scope of the present invention.
With reference to
As shown in
With reference to
Thus, the infrared lamp 38 in the portion extending inside the tubular element 24 rests on a plurality of support elements 62 distributed along the entire length of the infrared lamp 38. The support elements 62 are fastened to the cables 46, which are elastically tensioned between the stationary supports 22′, 22″. Therefore, the cables 46, due to the elastic tensioning produced by the elastic device 46, do not bend even at high temperatures since the thermal expansion of the cables 46 is compensated by the springs 56 of the elastic device 44. As a result, bending of the infrared lamp 38 is effectively avoided, even in the case of extremely long lamps.
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may be widely varied with respect to those described and illustrated, without thereby departing from the scope of the invention as defined by the claims that follow.
Number | Date | Country | Kind |
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102017000118834 | Oct 2017 | IT | national |
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Entry |
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Italian Search Report and Written Opinion dated Mar. 22, 2018 for Application No. IT201700118834. |
Number | Date | Country | |
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20190118560 A1 | Apr 2019 | US |