Epson 8900 Series - Manual (Page 167)

Epson FX Printer Emulation Mode 8-15
Margin Control Commands
The margin control commands let you set parameters related to the
left, right, bottom, and top margins and control print justification and
text centering.
Select Left Margin Justification
Escape sequence: ESC a NUL
Hexadecimal: 1B 61 00
This command causes the printer to justify any subsequent text to the
left margin.
Select Right Margin Justification
Escape sequence: ESC a STX
Hexadecimal: 1B 61 02
This command causes the printer to justify any subsequent text to the
right margin.
Select Full Justification
Escape sequence: ESC a ETX
Hexadecimal: 1B 61 03
This command causes the printer to add sufficient space to cause
each print line to occupy the entire space between the left and right
margins.
Select Text Centering
Escape sequence: ESC a SOH
Hexadecimal: 1B 61 01
This command causes the printer to center each print line between
the left and right margins.