Problem with valid_email return true for invalid email address

Hello,

I'm new to CI and just setup and working on the sign up form, but some how the valid_email rule in form validation is not working. I have tried the function valid_email() too and it's still not working. How come this email "a!b#c$e%g^h&j*[email protected]" can pass the validation?

PHP Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Welcome extends CI_Controller
{
    public function index()
    {
        $this->load->helper('email');

        if(valid_email('a!b#c$e%g^h&j*[email protected]'))
        {
            echo 'valid email';
        }
        else
        {
            echo 'invalid email';
        }
        $this->load->view('welcome_message');
    }
} 


This code is displaying "valid email". Did I miss something? Please help.