Epson Stylus Pro 7890 Series Reference Manual page 10

Epson MicroPiezo TFP print head technology allows the printer to share the same
physical ink channel between both Matte and Photo Black inks
The correct black ink mode is automatically used depending upon the printer driver
or front control panel settings
The process of switching between black ink modes is automatic
To reduce user errors, the user must confirm the switch at the front control panel
This technology is similar to the auto-switching process of the Epson Stylus Pro 7900
and 9900 Series printers
Black Ink Conversion
Photo Black to Matte Black
Matte Black to Photo Black
Epson MicroPiezo TFP Print Head Technology
User Verified Automatic Black Ink Mode Switching
Conversion Time
~2:07 min:sec
~2:55 min:sec
Ink Used
~1.13 ml
~3.34 ml