Printers have been developed that can print text and graphics with multiple colors directly onto the surface of 3D objects. These printers, known as direct-to-object (DTO) printers, enable a small number of objects, even a single object, to be printed. These printers are particularly advantageous in retail environments where unprinted objects can be kept and then printed to provide customized appearances to the objects. This flexibility enables an unprinted inventory of objects, such as various types of balls used in various sports, to be kept at the location and then printed with the logos of particular teams. Consequently, an inventory of objects with a particular logo or color scheme is not required.
One of the issues related to printing objects with a DTO printer is the wide variety of materials, such as metal, plastics, fabrics, and the like, that are used to make the 3D objects. These different materials have a corresponding wide range of surface energies. The surface energies of many of these materials adversely impact the adhesion and durability of ink images on these surfaces. Some of these materials require some type of surface pretreatment to increase the surface energy of the material for durable printing. Typical surface treatment processes include but are not limited to: (1) general cleaning using detergents or solvents, (2) texturing using sanding, sandblasting, plasma etching or the like, (3) low pressure plasma exposure or plasma etching, (4) atmospheric pressure plasma treatments, such as corona, chemical corona, blown arc, plasma jet, and blown ion processes, (5) the application of chemical primers, and (6) flame treatment of surfaces.
Currently, many facilities having DTO printers manually treat the objects prior to printing. Objects requiring only hand buffing and an isopropyl alcohol (IPA) wipe are amendable to manual treatment, while other objects requiring more involved treatments, such as significant exposure time in a low pressure plasma chamber, are not as amenable. Other objects may require a series of different types of surface treatment to achieve optimal results. For instance, some objects are best prepared for printing by hand buffing the object, then applying an IPA wipe followed by flame treatment of the surface. The useful lifetime of surface treatments is variable and range from a few minutes to months depending on the material treated, the process used to treat the material, and the environment in which the object is stored. The general rule of thumb is that the more aggressive the treatment is to get an ink to wet and adhere to a material, the shorter the duration of the treatment. Therefore, a system that successfully treats a wide range of materials, automates the surface treatment procedure to remove human variability and exposure to chemicals, and treats the objects immediately prior to printing would be useful.