The Leicester-born keyboard player, who had pancreatic cancer, died in London on Monday.
A statement on his website said he had passed “from Darkness to Light”.
The statement said Lord was “surrounded by his loving family” when he died.
Last year, Lord told fans he was “fighting cancer and will therefore be taking a break from performing while getting the treatment and cure”.
In a message on his website dated August 9, 2011, he added: “I shall of course be continuing to write music – in my world it just has to be part of the therapy – and I fully expect to be back in good shape next year.”
Lord started playing the piano in his family home and took classical music lessons before turning to jazz and rock’n'roll.
The band were critical favourites but never translated that into commercial success and split up.
Lord then went on tour with manufactured psychedelic pop combo The Flowerpot Men, who had scored a hit with Let’s Go To San Francisco, before joining Deep Purple in 1968.
The heavy rockers sold more than 100 million albums – many featuring Lord’s classically inspired keyboards.
But their most famous song was the simple Smoke On The Water with its trademark riff.