Brother TD-4100N - Manual (Page 14)

Pitch
Pitch refers to the spacing between neighboring characters.
When characters are arranged with a fixed pitch, they will be evenly spaced.
If characters extend over several lines, they will align in straight rows.
When characters are arranged with a proportional pitch, the spacing will vary depending on
the character.
(For example, "W" is wide but "I" is narrow.)
As a result, the excess space between characters is eliminated and the text appears more
compact.
If a fixed pitch is applied to a font that is better with a proportional pitch, all characters are
given the same width as the widest character in the font.
This makes it possible to evenly space the characters of a proportional-pitch font without
having to change the font.
If a proportional pitch is applied to a font that is better with a fixed pitch, all characters are
given the same width, appearing the same as with a fixed pitch.
14
Fixed spacing
ｗ
ｃ
Variable spacing
Ｃ Ｉ
ａ ｂ ｃ ｂ ａ
Fixed spacing
ｗ
Variable spacing
Ｃ Ｉ
ｗ
Variable spacing
Ｃ Ｉ ｗ
Fixed spacing
Ｃ Ｉ
Variable spacing
ｗ
Fixed spacing
Ｃ Ｉ ｗ Ｃ Ｉ