The Double Spacing button controls whether the print
  job output is double-spaced. When this button is turned
  on, a blank line will be inserted on the printout after
  each line in the file.

  To use the Double Spacing option:

  1. Move the pointer to the Double Spacing button.

  2. Click MB1 on the button. When turned on, the button
     becomes highlighted.

  3. Click on the OK button.

  Off is the default setting.