Cookies not setting

[eluser]jvk22[/eluser]
I'm trying to set a cookie using the input class, but no cookie is generated. Here's the code

Code:

if($this->uri->segment(3) != '')
        {
            $tc = array(
                'name'   => 'r_id',
                'value'  => 'sdfsdfsdf',
                'expire' => '86500',
                'domain' => '.'.site_url(),
                'path'   => '/',
                'prefix' => '',

            );

             $this->input->set_cookie($tc);
        }

        echo $this->input->cookie('r_id');