View
<form role="form" action="<?php echo base_url().'laporan'?>">
<input type = "text" id="tahun" name="tahun" class="form-control" placeholder="Masukkan Tahun" required/>
</form>

//Tombol Download
<?php echo form_open('laporan/download_zip'); ?>
   <div align="center">
      <input type="submit" name="but_createzip2" class = "btn btn-primary" value="Download Zip" />
   </div>
<?php echo form_close(); ?>
<!-- Disini saya tampilkan table list laporan berdasarkan Tahun -->

Controller
public function index(){
        $tahun          = $this->input->post('tahun');
        $data['lists']  = $this->laporan_model->list_laporan($tahun);

        $data['nama']   = $this->session->userdata('username');

        $this->load->view('templates/header',$data);
        $this->load->view('laporan', $data);
        $this->load->view('templates/footer');
}

public function download_zip() {
// Read files from directory
$tahun = $this->input->get('tahun');
if($this->input-post('but_createzip2') != NULL){
// File name
    $filename = $tahun . _laporan.zip";
    // Directory path (uploads directory stored in project root)
    $path = './uploaded/laporan/'.$tahun.'/';

    // Add directory to zip
    $this->zip->read_dir($path, FALSE);

    // Save the zip file to archivefiles directory
    $this->zip->archive('./uploaded/backup_laporan/'. $filename);

    // Download
    $this->zip->download($filename);
    }

    // Load view
    $this->load->view('v_detail_laporan');
}