$this->load->library('ciqrcode');

header("Content-Type: image/png");
$params['data'] = 'This is a text to encode become QR Code';
$this->ciqrcode->generate($params);

$this->load->library('ciqrcode');

$params['data'] = 'This is a text to encode become QR Code';
$params['level'] = 'H';
$params['size'] = 10;
$params['savename'] = FCPATH.'tes.png';
$this->ciqrcode->generate($params);

echo '<img src="'.base_url().'tes.png" />';

$this->load->library('ciqrcode');

$config['cacheable']	= true; //boolean, the default is true
$config['cachedir']		= ''; //string, the default is application/cache/
$config['errorlog']		= ''; //string, the default is application/logs/
$config['quality']		= true; //boolean, the default is true
$config['size']			= ''; //interger, the default is 1024
$config['black']		= array(224,255,255); // array, default is array(255,255,255)
$config['white']		= array(70,130,180); // array, default is array(0,0,0)
$this->ciqrcode->initialize($config);