private function _writeCFHeader(){
		$record	  = 0x01B0;			   // Record identifier
		$length	  = 0x0016;			   // Bytes to follow

		$numColumnMin = null;
		$numColumnMax = null;
		$numRowMin = null;
		$numRowMax = null;
		$arrConditional = array();
		foreach ($this->_phpSheet->getConditionalStylesCollection() as $cellCoordinate => $conditionalStyles) {
			foreach ($conditionalStyles as $conditional) {
				if($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_EXPRESSION
						|| $conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CELLIS){
					if(!in_array($conditional->getHashCode(), $arrConditional)){
						$arrConditional[] = $conditional->getHashCode();
					}
					// Cells
					$arrCoord = PHPExcel_Cell::coordinateFromString($cellCoordinate);
					if(!is_numeric($arrCoord[0])){
						$arrCoord[0] = PHPExcel_Cell::columnIndexFromString($arrCoord[0]);
					}
					if(is_null($numColumnMin) || ($numColumnMin > $arrCoord[0])){
						$numColumnMin = $arrCoord[0];
					}
					if(is_null($numColumnMax) || ($numColumnMax < $arrCoord[0])){
						$numColumnMax = $arrCoord[0];
					}
					if(is_null($numRowMin) || ($numRowMin > $arrCoord[1])){
						$numRowMin = $arrCoord[1];
					}
					if(is_null($numRowMax) || ($numRowMax < $arrCoord[1])){
						$numRowMax = $arrCoord[1];
					}
				}
			}
		}
		$needRedraw = 1;
		$cellRange = pack('vvvv', $numRowMin-1, $numRowMax-1, $numColumnMin-1, $numColumnMax-1);

		$header	  = pack('vv', $record, $length);
		$data	  = pack('vv', count($arrConditional), $needRedraw);
		$data     .= $cellRange;
		$data     .= pack('v', 0x0001);
		$data     .= $cellRange;
		$this->_append($header . $data);
	}