Epson B 310N - Manual (Page 122)

Replacing Consumables 122
6. Hold the ink cartridge with the arrow mark facing up and pointing to the rear of the
printer, and then insert it into the slot.
Note:
Hold the printer with your hand when you install the ink cartridge.
c
Caution:
Do not remove and reinsert cartridges more often than necessary. Doing so can
compromise the needle valve seal and allow air to enter the ink tubes, causing nozzle
loss.
7. Move the cartridge lever to the locked position.