Must an impure bed be purified if one sits on it to read the Qur'an, knowing that one does not pray on it?

It is permissible to recite [the Qur'an] on an impure mattress, though it is disliked. It should be purified or changed, for among the etiquettes of reciting the Qur'an is for the reciter to be in a clean and pure place, out of reverence for the Book of Allah. The jurists have stipulated the dislike of reciting the Qur'an in dirty places, and they have recommended recitation in a clean place with the reciter being in a state of purity. Al-Dusuqi mentioned the dislike of dhikr (remembrance of Allah) and recitation in roads and impure places. Al-Suyuti stated that it is sunnah (definition) to recite in a clean place, and the best of places is the mosque. Some people disliked recitation in bathrooms and on the road.