Trying to get property of non-object - with QR code

Hello everyone I am creating a pdf and inside the pdf I am placing a qr code with the data of N person but I have an error when setting the values to my QR code I get this error

but when I enter my sql statement, this appears

and finally this is in my controller:

 public function print_qr() {
    $res = $this->input->get('numero');
    $nombre = $this->input->get('name');
    $archivo = $this->resolucion->extraer_datos_qr($res, $nombre);

    $qr_code_config = array();
    $qr_code_config['cacheable'] = $this->config->item('cacheable');
    $qr_code_config['cachedir'] = $this->config->item('cachedir');
    $qr_code_config['imagedir'] = $this->config->item('imagedir');
    $qr_code_config['errorlog'] = $this->config->item('errorlog');
    $qr_code_config['ciqrcodelib'] = $this->config->item('ciqrcodelib');
    $qr_code_config['quality'] = $this->config->item('quality');
    $qr_code_config['size'] = $this->config->item('size');
    $qr_code_config['black'] = $this->config->item('black');
    $qr_code_config['white'] = $this->config->item('white');
    $this->ci_qr_code->initialize($qr_code_config);

    $image_name = 'codigoQR' . ".png";

    $codeContents = "Nombre y Apellidos:";
    $codeContents .= "\n";
    $codeContents .= $archivo->NOMBRES_COMPLETOS;
    $params['data'] = $codeContents;
    $params['level'] = 'H';
    $params['size'] = 2;
    $params['savename'] = FCPATH . $qr_code_config['imagedir'] . $image_name;
    $this->ci_qr_code->generate($params);
    $this->data['qr_code_image_url'] = base_url() . $qr_code_config['imagedir'] . $image_name;
    $file = $params['savename'];
    return $file;
}