received by the International Bureau on 21 July 2015 (21.07.2015)

1. A heat sensitive carrier (1) provided by a heat sensitive layer (2) to be colored by applying heat and a removable aqueous flexo covering paint scheme of layers arranged on the heat sensitive layer (2) , characterized in that the paint scheme of layers comprises a coat of lacquer (3) containing 70 % acrylate oligomer, 22 % acrylate monomer, 5 % photo-initiator and 3 % silicone is arranged on the heat sensitive layer (2); a disperse parting layer (4) containing 20 % soot paste with 35% of soot, 25 % aqueous acrylate emulsion, 6 % calcined kaolin, 1 % antifoam agent and spread improver, 3 % rheological modifier and 45 % water arranged on the coat of lacquer (3); and a topcoat paint layer (5) containing carbon nanotubes functionalized by hydroxyl, carbonyl and carboxy groups arranged on the disperse parting layer (4), and wherein measuring field (9) is printed with an ink containing carbon nanotubes directly onto the surface of the heat sensitive carrier (1).

2. The heat sensitive carrier (1) according to claim 1, characterized in that the length of the carbon nanotubes arranged in the topcoat layer (5) is between 4-20 μιη.

3. The heat sensitive carrier (1) according to claim 2, characterized in that the topcoat layer (5) is formed by 32% of an aluminum paste containing 70% Al, 3% nanotube paste, 60% aqueous acrylate emulsion, 1% antifoam agent and spread improver, and 4 % of water.

4. The heat sensitive carrier (1) according to claim 3, characterized in that the carbon nanotube paste consists of 5% hydrophilized carbon nanotubes having a length of 4-20 μιη, 20% aqueous acrylate emulsion, and 2% of an antifoaming and spread improver agent, 0.3% pH adjusting additive, 0.2% biocide additive, 3% isopropyl alcohol, and 69.5% of water.

5. Apparatus (10) for thermal printing of a heat sensitive carrier (1) provided by a heat sensitive layer (2) to be colored by applying heat and preprinted by a removable aqueous flexo covering paint scheme of layers including a topcoat paint layer (5) containing carbon nanotubes functionalized by hydroxyl, carbonyl and carboxy groups, the apparatus comprising a housing (11) provided by a reel (12) adapted for storing and dispensing said carrier (1); a transfer and counterpressure roller (G); and a thermal printing head (6), characterized in that the apparatus further comprising a measuring element (13) for measuring electric resistance of a measuring field (9); a measuring table (13a); an air blower system (19) capable of adjusting the air temperature prevailing inside the housing (11); a sensor (20) for detecting actual position of

1 themeasuring field (9) and for determining the operation of the measuring element (13); a reservoir (21) containing air of 0% relative humidity (RH) and provided by an air nozzle (21a); an evaporative heating element (22); a reservoir (23) containing water and connected to a fluid atomizing nozzle (23 a); and an electronic control means (E) controlling the operation of the nozzles (21a, 23 a) of the reservoirs (21,23), the air blower system (19) as well as said heating element (22) according to a value of electric resistance measured by the measuring element (13).

6. Apparatus according to claim 5, characterized in that the measuring element (13) measuring the electric resistance of said measuring field (9) comprises at least two electrodes (14a, 14b) provided by an insulating edge (17).

7. An apparatus according to claim 6, characterized in that the electrode (14a, 14b) consists of a silver-plated copper block (15) having an air duct (16) formed thereinside, which is connected to a vacuum space (18) and led onto a contact surface (15a) of the copper block (15).

8. An apparatus according to claim 7, characterized in that the reservoir (21) containing air with 0% RH relative humidity consists of a tank heated by electric resistance means.

9. Apparatus according to claim 8, characterized in that a chamber filled with hydroscopic mineral is connected to the reservoir (21) containing air with 0% RH relative humidity.

10. A method for thermal printing of a heat sensitive carrier (1) provided by a heat sensitive layer (2) to be colored by applying heat and preprinted by a removable aqueous flexo covering paint scheme of layers including a topcoat paint layer (5) containing carbon nanotubes functionalized by hydroxyl, carbonyl and carboxy groups, the method comprising the steps of subjecting the heat-sensitive layer (2) of the carrier (1) to heat radiation generated by a thermal printing head (6) characterized in that before applying said thermal radiation, measuring field (9) being formed on the heat- sensitive layer (2) of the carrier (1); determining experimentally a function (Fr) between the electric resistance and temperature as well as relative humidity of environment of the flexo covering paint scheme of layers; then determining a value of relative humidity (RHM) belonging to a maximum of a function (Fs) between thermal conductivity and temperature (Tl, T2, T3) as well as relative humidity of environment of the flexo covering paint scheme of layers; measuring electric resistance (Rl) of the measuring field (9); determining relative humidity (RH1) of the measuring field (9) by using the value of the resistance (Rl) and the function (Fr); and changing the value of relative

2 humidity (RHl) into the value of relative humidity (RHM) in a space surrounding the carrier (1).

11. A method according to claim 10, characterized by forming a measuring field (9) on the heat-sensitive layer (2) of the carrier (1), consisting of a disperse parting layer (4) containing 20 % soot paste with 35% of soot, 25 % aqueous acrylate emulsion, 6 % calcined kaolin, 1 % antifoam agent and spread improver, 3 % rheological modifier and 45 % water, and a topcoat paint layer (5) containing carbon nanotubes functionalized by hydroxyl, carbonyl and carboxy groups arranged on the disperse parting layer (4).

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