how to enable bipublisher.log file logs on Oracle BI Publisher server

I have facing issue to print logs inside the bipublisher.log file. I have followed Troubleshooting Oracle BI Publisher Enterprise 11g (Doc ID 1387643.1) doucment but still not printing logs inside bipublisher.log file.

Just empty file bipublisher.log created inside the /oracle/<bip home>/user_projects/domains/bifoundation_domain/servers/bi_server1/logs/bipublisher/ folder structure.

I am using BIP 11.1.1.5 version with OBIEE server connectivity.

Please suggest some solution to resolve this issue.

Thanks & Regards,

Pankaj Bonde