Epson STYLUS COLOR II Setup Manual page 20

7. The color cartridge, which is larger, goes on the right. Install
the black ink cartridge on the left. Lower the cartridges into
their holders with the labels facing up and the arrow on the
top pointing toward the back of the printer.
Be sure to install both ink cartridges. The printer will not
work if only one cartridge is installed.
8. Push down the ink cartridge clamps until they lock in place.
1-8
Installing the Printer