Disable font hinting for specific fonts.

The built in font-hinting support in Ubuntu sometimes does not work very well with specific fonts. The following bit of code in your ~/.fonts.conf can disable hinting for specific fonts.
<match target="font">
    <test name="family" qual="any">
      <string>UmePlus P Gothic</string>
    </test>
    <edit name="hinting">
      <bool>false</bool>
    </edit>
</match>
Replace "UmePlus P Gothic" with the name of your font.