9 downloadable computer software for operating 3D printing machines and associated materials and equipment, and computers and computer peripheral devices for 3D printing machines and associated materials and equipment; computers and computer hardware for printing; optical, weighing, measuring, signalling, detecting, testing and inspecting apparatus and instruments for 3D printing machines, namely, digital transmitters; component parts for printers, namely, ink supply components for use with printers, namely, unfilled ink cartridges; computer hardware for use with print heads; computer interface components for printers, namely, computer network interface devices; downloadable computer software for controlling print quality of printers; downloadable computer software for reporting ink temperature of printers; downloadable computer software for reporting status of the print head in printing; downloadable computer software for use in adjusting print quality of printers; downloadable computer software for use in connection with printers, namely, for operating printers; downloadable computer software for use with print heads, namely, for operating and controlling print heads; computer hardware for controlling print quality; computer hardware for reporting ink temperature; computer hardware for reporting status of the print head in printing; computer hardware for use in adjusting print quality; computer hardware for use in printing or in connection with printers; electric changeover switches in printers; recorded and downloadable firmware for optimizing performance of print heads; electronic control units for controlling ink flow rates, ink temperature and pressure; ink jet document printers; ink management and supply systems comprised of ink pumps being structural parts of computer printers for documents; printer control systems comprised of connection cables and printer interfaces in the nature of computer network interface devices; ink-supply system, unfilled, comprised of ink reservoirs, ink pumps, ink supply lines and ink connectors, being parts of ink jet document printers; print heads for computer printers for printing documents; print heads for ink-jet document printers; print heads for industrial inkjet printers; computer hardware, namely, printer buffers; printer programmes, namely downloadable software for installing print drivers for operating printers; document printers for computers; print heads for document printers; downloadable software for controlling print heads for document printers; downloadable controlling software for computer printers for printing documents; digital colour document printers; downloadable electronic publications, namely, books, manuals, newsletters, and reports in the field of printing; downloadable software applications for use with operating three dimensional printers; laser document printers; laser colour printers for documents; thermal printers; datapath systems comprised of data processors, computer memory hardware, input and output devices for computers; datapath systems and components for print heads, namely, data processors, computer memory hardware, input and output devices for computers; parts and fittings for the aforesaid goods, namely, ink reservoirs, ink pumps, ink supply lines and ink connectors, all unfilled, and printer control systems comprised of connection cables and printer interfaces in the nature of computer network interface devices