Hi.

If you wanna fix your favorite Japanese fonts, you can do it.

In Japanese fonts, the "Japanese font name"  would be related to default font-family, like "Sans" and/or "Serif".
for relations of them, if you're using lucid Japanese remix, we usually use below:

/etc/fonts/conf.d/69-language-selector-ja-jp.conf

But, this conf has an effect on whole accounts in your PC. So I can suggest account-specified fonts conf.

1. copy that conf to your $HOME/ as .fonts.conf (command below)

cp /etc/fonts/conf.d/69-language-selector-ja-jp.conf $HOME/.fonts.conf

2. Find a section showing "sans-serif" settings. For example, my .fonts.conf is like that,

<match target="pattern">
        <test name="lang" compare="contains">
            <string>ja</string>
        </test>
        <test qual="any" name="family">
            <string>sans-serif</string>
        </test>
        <edit name="family" mode="prepend" binding="strong">
            <string>VL Pゴシック</string>   
            <string>meiryo</string>
            <string>DejaVu Sans</string>
            <string>Takao Pゴシック</string>
            <string>IPA Pゴシック</string>
            <string>IPA モナー Pゴシック</string>
            <string>UmePlus P Gothic</string>
            <string>梅Pゴシック</string>
            <string>さざなみゴシック</string>
            <string>東風ゴシック</string>
        </edit>
    </match>

3. Replace entries you wanna desire up to top, like that,

<match target="pattern">
        <test name="lang" compare="contains">
            <string>ja</string>
        </test>
        <test qual="any" name="family">
            <string>sans-serif</string>
        </test>
        <edit name="family" mode="prepend" binding="strong">
            <string>Takao Pゴシック</string>
            <string>VL Pゴシック</string>   
            <string>meiryo</string>
            <string>DejaVu Sans</string>
            <string>IPA Pゴシック</string>
            <string>IPA モナー Pゴシック</string>
            <string>UmePlus P Gothic</string>
            <string>梅Pゴシック</string>
            <string>さざなみゴシック</string>
            <string>東風ゴシック</string>
        </edit>
    </match>

4. Save file, and reboot your PC.

Best regards.

Oh, that's not your problem.

If you're using Gnome, it would be better to using "language-support" GUI tool. It's more helpful to solve dependencies in Japanese environment.
Select language to Japanese, and system will guide you to automatic packages downloading and installing them.

And then, Creating that file, I suppose that.

Try it.

I'm glad to help you. =)