Samsung SL-C1810W-XAA - Manual (Page 56)

Available consumables
56 3. Maintenance
Depending on the options, percentage of image area and job mode used,
the toner cartridge’s lifespan may differ.
When purchasing new toner cartridges or other consumables, these must
be purchased in the same country as the machine you are using. Otherwise,
new toner cartridges or other consumables will be incompatible with your
machine due to different configurations of toner cartridges and other
consumables according to the specific country conditions.
Samsung does not recommend using non-genuine Samsung toner
cartridge such as refilled or remanufactured toner. Samsung cannot
guarantee non-genuine Samsung toner cartridge's quality. Service or repair
required as a result of using non-genuine Samsung toner cartridges will not
be covered under the machine’s warranty.