Print image in Zebra QLn420

I am new to Zebra printers - Android SDK. I am trying to print an image from android application.

I followed the documentation to create an Insecure Bluetooth connection with the printer and sent the bitmap for printing.

This works perfectly fine but I am getting blank page in the beginning and end of the actual image.

I tried to calibrate the printer, still I'm getting this problem.

Is there anyway to resolve this issue? Thanks in advance.