Build materials for 3D printing applications are described herein which, in some embodiments, comprise a dye component operable to alter spectral characteristics of the printed part over the course of the build cycle. In some embodiments, for example, the dye component can provide desirable light penetration depth during article printing and sufficient optical clarity during final light curing processes.

Thermochromic ink composition for ink jet printing, liquid at room temperature, comprising: a) a solvent; b) a binder; c) a heat resistant, and water or steam resistant pigment; d) a heat sensitive, and water or steam sensitive, dye;
wherein the pigment and the dye are selected to be complementary in the colour spectrum, and wherein said dye is capable of undergoing decomposition upon exposure to both heat and water or steam so that the colour of the ink composition or of a marking printed using said ink composition changes to the colour of the pigment upon exposure to both heat and water or steam.

Method for marking a substrate by spraying said ink composition onto this substrate, and substrate provided with a marking obtained by drying and/or absorption of said ink composition.

Method of indicating sterilization or pasteurization or autoclaving of a substrate using said ink.

Thermochromic ink composition for ink jet printing, liquid at room temperature, comprising: a) a solvent; b) a binder; c) a heat resistant, and water or steam resistant pigment; d) a heat sensitive, and water or steam sensitive, dye;
wherein the pigment and the dye are selected to be complementary in the colour spectrum, and wherein said dye is capable of undergoing decomposition upon exposure to both heat and water or steam so that the colour of the ink composition or of a marking printed using said ink composition changes to the colour of the pigment upon exposure to both heat and water or steam.

Method for marking a substrate by spraying said ink composition onto this substrate, and substrate provided with a marking obtained by drying and/or absorption of said ink composition.

Method of indicating sterilization or pasteurization or autoclaving of a substrate using said ink.

An ink jet recording apparatus includes at least one aqueous ink composition, at least one ink encasement in which the aqueous ink composition is encased, a recording head that ejects the aqueous ink composition, and a carriage configured to move the ink encasement and the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the aqueous ink composition is loaded, and the maximum external length of the ink encasement in the direction parallel with the direction in which the carriage moves back and forth is 30.0 mm or less.

An ink jet recording apparatus includes at least one aqueous ink composition, at least one ink encasement in which the aqueous ink composition is encased, a recording head that ejects the aqueous ink composition, and a carriage configured to move the ink encasement and the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the aqueous ink composition is loaded, and the maximum external length of the ink encasement in the direction parallel with the direction in which the carriage moves back and forth is 30.0 mm or less.

An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a water-soluble dye and a polyhydric alcohol with a normal boiling point of 270° C. or above, with the percentage of the polyhydric alcohol being 26.0% by mass or less of the total amount of the ink composition.

An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded and also has a detector that detects the amount of ink composition encased. The ink composition contains a surfactant with an HLB of 6 or less.

An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded and also has a detector that detects the amount of ink composition encased. The ink composition contains a surfactant with an HLB of 6 or less.

An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 105.0 nm or less.

An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 105.0 nm or less.