Depending on your use case there a three different options when it comes to the question of which access_token to use:
- Use any sort of access_token to get all posts that are public
- Use an user access_token to get all posts visible to the user the token belongs to
- Use a page access_token to get all posts
As far as I understand you, you want to get all posts from your page, regardless of any restrictions that may apply to a user that is viewing the feed (example: age restrictions, country restrictions). In that case use the page access_token for the page you want to get the feed from.
You can get the page token by calling /me/accounts
[1], look for the page object and get the access_token for that page.
You can also read about it in the Graph API documentation [2] for pages.
[1] https://developers.facebook.com/tools/explorer/?method=GET&path=me%2Faccounts&version=v2.0
[2] https://developers.facebook.com/docs/graph-api/reference/v2.0/page/feed#read