Epson 1000 Reference Manual page 236

If you select proportional, 10 cpi and condensed, determine
margin units. If you change the setting of ORIENT., PAGE
SIZE, or WIDE PAGE (when PAGE SIZE is set to A4 or F4), the
left margin defaults to 0.
R-MARGIN-Use this option to set the right margin. Margin
units are determined by current pitch (characters per inch) and
the condensed setting (ON or OFF). The factory setting is 80.
Menu/submenu
R-MARGIN
If you select proportional, 10 cpi and condensed, determine
margin units. If you change the setting of ORIENT., PAGE
SIZE, or WIDE PAGE (when PAGE SIZE is set to A4 or F4), the
right margin defaults to the setting in the following table:
Availableoption
80
LQ and FX Emulation Modes C-5