What event receiver is triggered when the content of an existing Word document is updated/changed? ItemUpdated works when the properties on the document are updated (e.g. changing a content type column on the item/document causes ItemUpdated to get called).
Both the ItemUpdating and ItemUpdated event receivers get called when you update a document in a document library.
The event receiver should work even when you update any changes to the corresponding documents as the code is written under Item Updating. You can check it by enabling the Versioning of the documents. Try to check weather the version of the document changes when you update every time. If version changes... then its sure that event receiver is fired there...
This thread was very helpful: file rename