@devraj,
Exporting chart as PDF seems to be working fine. Please take a look at this JSFiddle for exporting chart as PDF using jsPDF.
If it doesn’t help, can you kindly create a JSFiddle reproducing the issue you are facing and share it with us so that we can look into the code, understand the scenario better and help you out?
___________
Indranil Deo
Team CanvasJS