Board Thread:General Discussion/@comment-5398287-20130809180907/@comment-8986886-20130809214846

Ichigo's first Hollowfication was a result of his Chain of Fate becoming completely encroached. Under such circumstances any Plus will become a Hollow. The Hollowfication process was halted, when Ichigo discovered his Shinigami powers, with the aid of old man Zangetsu (his Quincy powers)

If Ichigo's Shinigami powers and his inner Hollow were originally merged as one, that means Ichigo was, ironically, saved from becoming a Hollow, by his own inner Hollow.