After replacing the toner cartridge in your Okidata B4600, you'll need to reset the counter to ensure that the system keeps track of the level. On some printers this is done automatically. But in the B4600 the user manually completes the reset. Don't reset the counter unless you've replaced the toner cartridge. Doing so is not beneficial and will not make your toner last longer.
Press the "Online" button on the control panel. This is located on the left side of the control panel, directly beneath the "Menu" button.
Press the "Menu" button repeatedly to scroll through the menu options. Pay attention to the display screen. Stop pressing "Menu" when the display shows "Maintenance."
Press the "Select" button on the right side of the control panel to access the "Maintenance" menu.
Press the "Item" button repeatedly until "Drum Counter Reset" displays on the screen. The "Item" button is directly to the right of the "Menu" button.
Press "Select" to reset the counter, and then press "Online" to return to the operating mode.