Thank you very much for your question. It is our pleasure to answer it.

Almighty Allah says in the Quran: 

That this is a Glorious Quran. Inscribed in a well-guarded Book. That none can touch, except the purified. (Al-Waqi`ah 56: 77-79) 

It is clear from the verses that one should touch the Quran (hard copy or book) only when one is pure and clean.

Thus, it is always preferred to be in a state of wudu' (ablution) when one recites the Quran from the Book. However, if one is reciting from memory, then there is no need to be in wudu. And if one is sexually impure, then he must not even touch the Quran, unless he purifies himself with a full bath or ghusl.

I hope this answers your question.