Having just had a query about this printer I've found an image of the CX/DX8400 rear which shows the usual trapdoor opening.



Waiting for confirmation but it would seem likely that this printer has the same sort of waste tube access as the R300, RX620, etc..


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Printers: (Canon) MP500/830, MX700, iP4000/4200/4300/4500/5200, iX4000(A3) (Epson) C84/86, D88, CX6600, R285/800/1900 (HP) K550, K850, K5400, L7680