Do I need to clear Chinese immigration and if so, can I use the 24 hrs visa exemption?

I will arrive in Shanghai (Pudong) at 8:30 am and will leave on a flight for Japan (from Pudong) at 12 noon the same day. My flight is not a connecting flight so I will need to collect my bags and check in again. After two weeks in Japan I will return to China and will have a business type for this second visit. Will this cause any problems in obtaining the 24 hrs exemption?

Thank you!
Katie