Customer all files are downloaded in a zip with Codeigniter

codeigniter_multiple_file_downloaded_zip.php

<?php
    function download_zip($customer_id=NULL){
        $this->load->library('zip');
        $this->load->helper('file');
        $query = $this->db->query("SELECT * FROM customers WHERE customer_id = $customer_id")->row();
        $path ='customer_files/';
        $arr_file = explode(',', $query->cust_file);
        foreach ($arr_file as $a_file) {
            $this->zip->read_file($path.$a_file,TRUE);
            //$this->zip->read_file($path.$a_file,FALSE); //Folder Directory won't be added
        }
        $this->zip->download("all_customer_files");
    }
?>