Abstract: A coating method which is characterized in that, when the surfaces of solid particles kept flowing are spray-coated with a thermally melted wax, a two-fluid nozzle adapted to mix a thermally melted wax with a heating gas in and eject the resultant mixture from one flow passage and eject a heating gas from the other flow passage is used, the two-fluid nozzle having spray ports of a diameter of 1.5 to 5.8 mm, and the two-fluid nozzle having no needle valve. According to this method, the use of an organic solvent for melting wax is omitted, and complicated operations for pulverizing a wax and for thermally melting the wax powder after it has been deposed on solid particles are not required. This method can also prevents clogging of the nozzle, powdering of the melted wax and forming of agglomerated solid, and permits simple and easy production of sustained release preparations and preparations for masking materials of unpleasant and bitter tastes.

Abstract: Disclosed are tablets having clear marks including letters, figures and the like which are impressed thereon wherein a material different in color tone from the portion other than the mark portion is deposited in the impressed valley portion and if necessary, these tablets are further applied with a coating and a method for producing the tablets.