HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part I

EN Horizontal Cursor Positioning Control Codes 6-9
BS - Backspace
Moves the current active position (CAP) left a distance equal to the
width of the last printed symbol or space. If the active position is
already at the left margin, no action is taken. If the cursor is currently
beyond the right margin, BS positions the cursor just to the left of the
right margin. When using fixed pitch fonts, the Backspace distance is
defined by the current print pitch (HMI setting).
When using proportionally-spaced fonts, a single Backspace moves
back to center the overstrike character. After printing the overstriking
character, the cursor returns to its position prior to the Backspace.
Multiple backspaces each move back the distance of the last printed
symbol or space. For example, if “world” was printed with a
proportional font and then 5 backspaces were performed, the
distance moved back would be five times the width of the “d.”
HT - Horizontal Tab
Moves the current active position (CAP) to the next tab stop on the
current line. The tab stops are at the left margin and every 8th column
between the left margin and the right bound of the logical page. If the
new horizontal position crosses the right margin, the new horizontal
position is set to the right margin. If the current HMI value is 0, the
command is ignored.