A tube holder assembly is provided for securing a medical tube such as an endotracheal tube to a patient. of no more than 1000 mPa\xb7s and provides a cured product displaying a breaking elongation of at least 5%. Amplitude information and phase information corresponding to different wavelengths which vary periodically in a direction traversing the multiplicity of areas, is recorded in the recording medium. Accordingly, accuracy of the toner supplier apparatus used for an electronic photograph printer in measuring the concentration of the toner can be improved, thereby permitting accurate control for the concentration in a printed image.