4809 - Carbon paper, self-copy paper and other copying or transfer papers (including coated or impregnated paper for duplicator stencils or offset plates), whether or not printed, in rolls or sheets:

This HTS category, 4809, encompasses specialized papers designed for the purpose of transferring ink or other marking substances from one surface to another. This includes traditional carbon paper, where a layer of pigment is coated onto a backing paper. It also covers self-copy paper, often referred to as carbonless copy paper, which utilizes microencapsulated dyes that react upon pressure to create an image on a receiving sheet. The scope extends to other transfer papers, including those prepared for use with duplicator stencils or as coatings for offset printing plates, regardless of whether they are supplied in rolls or sheets and irrespective of any pre-existing printing.

Within the broader context of Chapter 48, which deals with paper and paperboard, this category distinguishes itself by focusing specifically on the functional attribute of ink transfer rather than the general properties or end-uses of paper itself. While other paper categories might cover base papers for printing or specialized packaging materials, 4809 is reserved for those engineered to duplicate or transfer information through direct contact and pressure-induced chemical or physical reactions. It is crucial to differentiate this category from, for instance, plain writing paper (Chapter 48) or printed advertising materials (Chapter 49), as the defining characteristic here is the transfer mechanism inherent in the paper's construction and coating.

The subcategories within 4809 provide a further breakdown based on the specific type of transfer paper. 4809.20 specifically addresses self-copy paper, which relies on chemical reactions for duplication, differentiating it from the pigment-based transfer of traditional carbon paper. The residual items, not fitting into the self-copy classification, are then classified under 4809.90, which acts as a catch-all for other forms of carbon paper and specialized transfer papers used in printing processes.