How to update time and date in TFT lcd without any filling on screen

Hello,
I am using 2.4 inch LCD display with arduino mega,and i have attached DS1307 RTC module to it.I had set time and data on RTC module and can able to display on TFT lcd Screen.
Here my problem is for every second or minute or hour update the time will change and updated time will be printed , but here the updated time is printing on old time.That is the new time is printing on old time.

Code? And the type of display is more important... So also include links to ALL libraries used.