Latin Modern works fine with Japanese.
If "lmodern" is set for \font_roman the "lmodern.sty" package sets
sans-serif and teletype to Latin Modern fonts as well.
Therefore, \font_sans and \font_teletype are better left as "default"
(less preamble code) in the LaTeX source).
\language_package default
\inputencoding utf8-platex
\fontencoding global
-\font_roman "ae" "IPAexMincho"
+\font_roman "lmodern" "IPAexMincho"
\font_sans "default" "IPAexGothic"
\font_typewriter "default" "default"
\font_math "auto" "auto"
\language_package default
\inputencoding utf8
\fontencoding global
-\font_roman "default" "IPAexMincho"
+\font_roman "lmodern" "IPAexMincho"
\font_sans "default" "IPAexGothic"
\font_typewriter "default" "default"
\font_math "auto" "auto"
\inputencoding utf8-platex
\fontencoding global
\font_roman "lmodern" "IPAexMincho"
-\font_sans "lmss" "IPAexGothic"
-\font_typewriter "lmtt" "default"
+\font_sans "default" "IPAexGothic"
+\font_typewriter "default" "default"
\font_math "auto" "auto"
\font_default_family default
\use_non_tex_fonts false
\language_package default
\inputencoding utf8-platex
\fontencoding global
-\font_roman "default" "IPAexMincho"
+\font_roman "lmodern" "IPAexMincho"
\font_sans "default" "IPAexGothic"
\font_typewriter "default" "default"
\font_math "auto" "auto"
\inputencoding utf8-platex
\fontencoding global
\font_roman "palatino" "IPAexMincho"
-\font_sans "lmss" "IPAexGothic"
-\font_typewriter "lmtt" "default"
+\font_sans "default" "IPAexGothic"
+\font_typewriter "default" "default"
\font_math "auto" "auto"
\font_default_family default
\use_non_tex_fonts true
\inputencoding utf8-platex
\fontencoding global
\font_roman "palatino" "IPAexMincho"
-\font_sans "lmss" "IPAexGothic"
-\font_typewriter "lmtt" "default"
+\font_sans "default" "IPAexGothic"
+\font_typewriter "default" "default"
\font_math "auto" "auto"
\font_default_family default
\use_non_tex_fonts true
\language_package default
\inputencoding utf8-platex
\fontencoding global
-\font_roman "default" "IPAexMincho"
+\font_roman "lmodern" "IPAexMincho"
\font_sans "default" "IPAexGothic"
\font_typewriter "default" "default"
\font_math "auto" "auto"