No person shall assume the title licensed public weigher, or any title of similar import, perform the duties or acts to be performed by a licensed public weigher under this chapter, hold himself out as a licensed public weigher, issue any weight certificate ticket, memorandum or statement for which a fee is charged, or engage in the full-time or part-time business of public weighing, unless he holds a valid license as a licensed public weigher. As used in this section, “public weighing” means the weighing for any person, upon request, of property, produce, commodities or articles other than those which the weigher or his employer, if any, is either buying or selling.