For each of the situations, adjust the stty setting:
If the printer output is double-spaced,
replace 'stty_setting' with
either '-onlcr' or '-tabs'.
If there is no left margin and the text runs together,
replace 'stty_setting' with '-tabs'.
If the printer output zig-zags down the page,
replace 'stty_setting' with '-onlcr'.
(This is set by default, but you may have cleared it accidentally.)