TO TRANSFER HEAT

BACKGROUND

[0001 ] In some printing applications, a media passes through a print zone. An amount of ink is laid down on a media in the print zone. Then, the media may be extracted from the print zone and directed into a storage zone wherein it may be stored next to other pieces of media having ink thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a schematic view of a printing apparatus according to an example of the present disclosure.

[0003] Figure 2 is a schematic view of an extraction part of the example printing apparatus of figure 1 .

[0004] Figure 3 is a sideview of a printer according to another example of the present disclosure.

[0005] Figure 4 is a sideview of a deflector of the example printer of figure 3.

[0006] Figure 5 is a flowchart of an example printing method of the present disclosure. DETAILED DESCRIPTION

[0007] In one example, after it has passed through the print zone, the media passes through a downstream space delimited by a bottom face and a top cover. In order to ensure that the ink laid down on the media is completely dry, the bottom face is to transfer heat by conduction to the media coming across the downstream space.

[0008] In one example, an air flow is circulated in the print zone and an extraction part includes a primary path to collect the air flow from the print zone. In order to capture the vapors generated during the drying process and/or the curing process in the downstream space, the extraction part includes a secondary path to collect a flow from the downstream space.

[0009] In one example, the air flow has a component in a path direction of the media in the print zone. Hence, one avoids adding flows that leave the printer without passing through filters and generate pollution on the workspace.

[0010] In one example, a junction between the primary path and the secondary path is located at a constricted portion of the primary path. Thanks to the Venturi principle, this feature creates an area of low pressures that attracts vapors from the downstream space.

[0011 ] In one example, which is depicted on figure 1 , a printing apparatus 10 includes a print zone 12, a downstream space 14 and a storage zone 16. The storage zone 16 may include a media output roll. [0012] In this example, a direct orthonormal vector basis 18 is associated to the print zone 12. The vectors of the basis 18 may include a vector X, a vector Y and a vector Z. When the print zone 12 is arranged parallel to a plane horizontal surface, the vector Z is vertically, upwards oriented.

[0013] The printing apparatus 10 may be a direct to fabric dye sublimation printing apparatus. The printing apparatus 10 may be intended to print on textiles such as, for example, flags or polyester textiles or backlits.

[0014] A media 20 may be received in the print zone 12. After it has passed through the print zone 12, the media 20 may come across the downstream space 14. Then, the media 20 may be directed into the storage zone 16.

[0015] The printing apparatus 10 may include a print head 22 which may lay down an amount of ink 24 on the media 20 when it is in the print zone 12.

[0016] The downstream space 14 may be downwardly delimited by a bottom face 26. The bottom face 26 may include a heating element 27 to transfer heat by conduction to the media 20 when it comes across the downstream space 14. The media 20 may lean on the bottom face 26, on its side adjacent to the downstream space 14. The bottom face 26 may heat the media 20 coming across the downstream space 14 at a temperature between 80°C and 105°C. When it is heated at a temperature within this range, the media 20 may be completely dried before it enters in the storage zone 16. This will avoid an ink transfer issue between the printed face of the media 20 and the adjacent back side of the media 20.

[0017] In the case of dye sublimation printing, sublimation process may usually take place in a temperature frame from 180°C to 210°C, and may not take place at a temperature below 120 °C. Hence, when the bottom face 26 heats the media 20 at a temperature between 80°C and 105°C, the bottom face 26 does not trigger a sublimation process. [0018] In order to ensure a good thermal conductivity, the bottom face 26 may include a metal. The bottom face 26 may also have a thickness between 0.5 mm to 1 mm .

[0019] In order to improve the thermal conductivity between the bottom face 26 and the media 20, the bottom face 26 may include a curved surface 28. The curved surface 28 may have a curvature radius between 1 m and 1 .5 m. The center of the curvature radius may be opposite to the side on which the media 20 leans.

[0020] The downstream space 14 may be upwardly delimited by a top cover 30. In order to ensure that the vapors generated by the drying process of the media 20 in the downstream space 14 are moved in the same direction as the direction of the vector Y, the top cover 30 may be inclined with respect to the horizontal plane containing the vectors X and Y. For example, the top cover 30 may have an inclination angle a, with respect to the horizontal plane, within 10° to 80°.

[0021 ] The printing apparatus 10 may include an airflow generator 32. The airflow generator 32 may generate a warm airflow 34 within the print zone 12. The warm air flow 34 may have a temperature of 60 °C. At least a component of the warm airflow 74 may be parallel to a path direction of the media 20 in the print zone 12, that is in opposite direction to the vector Y. The warm air flow 34 may implement a first drying of the media 20 in the print zone 12. Hence, the media 20 may be completely dried when leaving the downstream space 14 due to the heating in the print zone 12 by convection with the air flow 34, and to the heating in the downstream space 14 by conduction with the bottom face 26. The heating in the print zone 12 may remove water from the media 20 whereas the heating in the downstream space may remove solvents from the media 20.

[0022] The printing apparatus 10 may include an extraction part 36 and an extraction system 38. With reference to figure 2, the extraction part 36 may include a primary path 40 which may have a constricted portion 42. The primary path 40 may collect the warm airflow 34 from the print zone 12. The primary path 40 may then evacuate the airflow 34 into the extraction system 38.

[0023] The extraction part 36 may include a secondary path 44.

The secondary path 44 may collect a flow 46 containing vapors generated by the drying process of the media 20 in the downstream space 14. [0024] The extraction part 36 may include a junction 48 between the primary path 40 and the secondary path 44. The junction 48 may implement a fluid communication between the primary path 40 and the secondary path 44. Hence, the vapor flow 46 circulating through the secondary path 44 may circulate through the primary path 40 into the extraction system 38. Hence, the extraction part 36 may collect vapors originated from two processes, or from a combination between them, which may include a drying process wherein liquid, for instance water or solvents, is removed liquid from ink, and a curing process wherein a polymerization of the ink may occur, for instance by cross-linking. The curing process may be obtained by applying energy, e.g. , from a LED source or a heater.

[0025] The junction 48 may be located at the constricted portion 42. Hence, thanks to the Venturi principle, the pressure decreases at the location of the junction 48, and the vapors generated between the bottom face 26 and the top cover 30 may tend to flow towards the extraction part 36, where they may be guided to the extraction system 38.

[0026] In another example, which is depicted in figures 3 and 4, a printer 50 may be a direct to fabric dye sublimation roll to roll printer. In such case, the printer 50 may be used for printing on a substrate 52 such as a textile 52. The substrate 52 may be provided by a media input roll 54, using a media drive roll 56. Once the printing operation is complete, the media 52 may be stored on a media output roll 58. [0027] The printer 50 may include a print chamber 60. The print chamber 60 may accommodate a printing carriage 62 which can eject ink onto the substrate 52.

[0028] Downstream the print chamber 60 on a media advance direction 64, and upstream the media output roll 58, the printer 50 may include a downstream chamber 66. Hence, the downstream chamber 66 may evacuate the substrate 52 from the print chamber 60 towards the media output roll 58. [0029] The downstream chamber 66 may include and may be delimited by a lower plate 68 and an upper wall 70. The upper wall may have an inclination angle with reference of an horizontal plane of the print chamber 60.

[0030] The lower plate 68 may include a heater 72. The heater 72 may then transfer thermal energy to the substrate 52 by conduction. The lower plate 68 may include a rounded face 74 in order to ensure that the media 52 is always in contact with the lower plate 68, on the side adjacent to the downstream chamber 66.

[0031 ] During the drying process of the media 52 in the downstream chamber 66, some vapors may be generated and may form a vapor flow 76. Thanks to the inclination of the upper wall 70, the vapor flow 76 is directed towards the print chamber 60.

[0032] The printer 50 may include a fan 78 that may generate an airflow 80 through the print chamber 60. The airflow 80 may be parallel to the media advance direction 64. The fan 78 may be associated with a coil heater 79 which, combined with the fan 78, may implement a first heating in the print chamber 60.

[0033] The printer 50 may include a deflector 82. The defector 82 may be located between the print chamber 60 and the downstream chamber 66.

[0034] With reference to figure 4, the deflector 82 may include a first duct 84 having a first end opening 86 and a second end opening 88. The first opening 86 may fluidly link the first duct 84 with the print chamber 60. The second end opening 88 may lead towards an extraction system 92 (see figure 3), as shown by the arrow 90. The extraction system 92 may be connected to a general exhaust that may take all the vapors outside the room. The extraction system 92 may include an active extraction system such as a fan or a pump.

[0035] Still referring to figure 4, the first duct 84 may include a smaller axial cross-section portion 94. That is, the area of the cross- section of the duct 84 is smaller in the portion 94 than in other portions of the duct 84.

[0036] The defector 82 may include a second duct 96. The second duct 96 may include a first end opening 98 which may be fluidly linked to the downstream chamber 66. At the end of the second duct 96 opposite the first end opening 98, the deflector 82 may include a fork 100. The fork 100 may fluidly link the first duct 84 and the second duct 96. The fork 100 may be located at the smaller axial cross-section portion 94.

[0037] Hence, the deflector 82 may collect, by means of the first duct 84, the airflow 80 from the print chamber 60. At the smaller axial cross-section portion 94, thanks to the Venturi principle, the airflow 80 decreases the pressure and the vapor flow 76 is attracted from the downstream chamber 66 in the second duct 96. The vapor flow 76 and the airflow 18 may then mixed together in the first duct 84 and may be directed towards the extraction duct 90.

[0038] Hence, the deflector 82 may collect vapors originated from a drying and/or a curing of the substrate 52.

[0039] In one example, which is depicted in figure 5, a printing method using the example printer of figures 3 and 4 will now be detailed.

[0040] The example method may include, at block 102, providing ink on the substrate 52 when it is in the print chamber 60. Meanwhile, the method may include providing an airflow 80 through the print chamber 60 to start drying the substrate 52.

[0041 ] The example method may include, at block 104, collecting the airflow 80 via the first duct 84 of the deflector 82. Meanwhile, the airflow 80 may be directed towards the extraction duct 90 and the extraction system 92.

[0042] The example method may include, at block 106, evacuating the substrate 52 from the print chamber 60 into the downstream chamber 66. In particular when colors are saturated, which happens often with direct to fabric dye sublimation printing applications, especially for flags and backlits, the substrate 52 may not be completely dry when it leaves the print chamber 60.

[0043] The example method may include, at block 108, heating the lower plate 68. By doing so, the substrate 52 may be heated by conduction and vapors may be evaporated from the substrate 52. This may result in drying completely the substrate 52 and generating the vapor flow 76. Then, the vapor flow 76 may be directed towards the deflector 82 thanks to the inclination of the upper wall 70.

[0044] The example method may include, at block 1 10, extracting the vapor flow 76 from the downstream chamber 66 through the second duct 96 of the deflector 82. The extraction may be implemented by means of the fork 100.

[0045] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.