See "Specifying Access Privileges for Documents Saved in Document Server", User
Guide (HTML).
• To prevent documents from being deleted automatically, set [Auto Delete File in
Document Server] to [Off], and then save the documents.
• Even if you change the settings to [Specify Days] or [Specify Hours] after documents
have been saved with [Auto Delete File in Document Server] set to [Off], the
documents will not be deleted automatically. Only the documents saved after a
setting change are deleted automatically.
See "Changing the Storage Period of Document Server or Specifying an Indefinite
Period", User Guide (HTML).