Windows api allowing direct communication with a scanner device

Hi everyone,
I would like to know if there is a function embedded in a windows API (NOT WIA scripting) that allows to communicate directly with a scanner device attached to a computer without using the built in interface of that scanner device. I want to create my custom form in C# that:
1- connects to the scanner device,
2- scan something and show it in a custom form on a click on a button
3- save it

Thanks everyone for any URL or advice you will provide me.

What about twain ?

An example here also.

There are 2 ways:
1) Twain
2) ISIS
These are common interfaces to work with scanners.