Do I need to clear immigration and stamp Chinese visa?

Hello,
I am going from Incheon to Hong Kong via Beijing. The flight from Incheon (Air China) lands in Beijing at 4:20pm and the next flight (also Air China) leaves at 5:30pm the same day. Will I have to clear immigration in Beijing and collect my bags, or do I just go right to my next flight without clearing immigration?

A concern I have, other than the short connection time, is that I am travelling in China after Hong Kong, so I do not want them to stamp my Chinese visa (single entry) when I am only just transiting and thus being without a valid visa upon my return to China.