update for Issue #2064 (changed docblocks which return $this or only call a method that returns $this to @return CI_DB_class_name)
diff --git a/system/libraries/Email.php b/system/libraries/Email.php
index 5d8fc8a..365a8bc 100644
--- a/system/libraries/Email.php
+++ b/system/libraries/Email.php
@@ -406,7 +406,7 @@
 	 * Initialize preferences
 	 *
 	 * @param	array
-	 * @return	void
+	 * @return	CI_Email
 	 */
 	public function initialize($config = array())
 	{
@@ -440,7 +440,7 @@
 	 * Initialize the Email Data
 	 *
 	 * @param	bool
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function clear($clear_attachments = FALSE)
 	{
@@ -474,7 +474,7 @@
 	 * @param	string	$from
 	 * @param	string	$name
 	 * @param	string	$return_path = NULL	Return-Path
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function from($from, $name = '', $return_path = NULL)
 	{
@@ -522,7 +522,7 @@
 	 *
 	 * @param	string
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function reply_to($replyto, $name = '')
 	{
@@ -558,7 +558,7 @@
 	 * Set Recipients
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function to($to)
 	{
@@ -586,7 +586,7 @@
 	 * Set CC
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function cc($cc)
 	{
@@ -614,7 +614,7 @@
 	 *
 	 * @param	string
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function bcc($bcc, $limit = '')
 	{
@@ -649,7 +649,7 @@
 	 * Set Email Subject
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function subject($subject)
 	{
@@ -664,7 +664,7 @@
 	 * Set Body
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function message($body)
 	{
@@ -693,7 +693,7 @@
 	 * @param	string	$disposition = 'attachment'
 	 * @param	string	$newname = NULL
 	 * @param	string	$mime = ''
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function attach($filename, $disposition = '', $newname = NULL, $mime = '')
 	{
@@ -746,7 +746,7 @@
 	 * Set Multipart Value
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_alt_message($str = '')
 	{
@@ -760,7 +760,7 @@
 	 * Set Mailtype
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_mailtype($type = 'text')
 	{
@@ -774,7 +774,7 @@
 	 * Set Wordwrap
 	 *
 	 * @param	bool
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_wordwrap($wordwrap = TRUE)
 	{
@@ -788,7 +788,7 @@
 	 * Set Protocol
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_protocol($protocol = 'mail')
 	{
@@ -802,7 +802,7 @@
 	 * Set Priority
 	 *
 	 * @param	int
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_priority($n = 3)
 	{
@@ -816,7 +816,7 @@
 	 * Set Newline Character
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_newline($newline = "\n")
 	{
@@ -830,7 +830,7 @@
 	 * Set CRLF
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Email
 	 */
 	public function set_crlf($crlf = "\n")
 	{
diff --git a/system/libraries/Encrypt.php b/system/libraries/Encrypt.php
index cdb0a64..e54ce49 100644
--- a/system/libraries/Encrypt.php
+++ b/system/libraries/Encrypt.php
@@ -122,7 +122,7 @@
 	 * Set the encryption key
 	 *
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Encrypt
 	 */
 	public function set_key($key = '')
 	{
@@ -419,7 +419,7 @@
 	 * Set the Mcrypt Cipher
 	 *
 	 * @param	int
-	 * @return	object
+	 * @return	CI_Encrypt
 	 */
 	public function set_cipher($cipher)
 	{
@@ -433,7 +433,7 @@
 	 * Set the Mcrypt Mode
 	 *
 	 * @param	int
-	 * @return	object
+	 * @return	CI_Encrypt
 	 */
 	public function set_mode($mode)
 	{
diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index 6853425..32f7da1 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -149,7 +149,7 @@
 	 * @param	mixed	$field
 	 * @param	string	$label
 	 * @param	mixed	$rules
-	 * @return	object
+	 * @return	CI_Form_validation
 	 */
 	public function set_rules($field, $label = '', $rules = '')
 	{
@@ -266,7 +266,7 @@
 	 *
 	 * @param	array
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Form_validation
 	 */
 	public function set_message($lang, $val = '')
 	{
@@ -288,7 +288,7 @@
 	 *
 	 * @param	string
 	 * @param	string
-	 * @return	object
+	 * @return	CI_Form_validation
 	 */
 	public function set_error_delimiters($prefix = '<p>', $suffix = '</p>')
 	{
@@ -829,7 +829,7 @@
 		{
 			return sprintf($line, $field, $param);
 		}
-		
+
 		return str_replace(array('{field}', '{param}'), array($field, $param), $line);
 	}
 
diff --git a/system/libraries/Zip.php b/system/libraries/Zip.php
index 9ecd0de..77cc45b 100644
--- a/system/libraries/Zip.php
+++ b/system/libraries/Zip.php
@@ -438,7 +438,7 @@
 	 * Lets you clear current zip data. Useful if you need to create
 	 * multiple zips with different data.
 	 *
-	 * @return	object
+	 * @return	CI_Zip
 	 */
 	public function clear_data()
 	{