Hello. My name is Michael. I can help you with your question. I would re-install the driver, but before doing that completely remove the previous driver. Here are the steps:
1. Click the [Printers & Scanners] icon in [System Preferences].
2.Select the printer you use on [Printers], then click [-].
3. Delete the printers that are registered, then close the [Print & Scan] dialog box.
4. Open Finder application of your Mac OS X.
5. Select [Go] → [Go to Folder] from the menu bar.
6. Enter the following folder locations, click [Go], then delete the files and folders.
Delete Example: You can delete files and folders by dragging them to the [Trash] icon in the Dock.
Files and folders to delete
Delete all the following files in the folders.
(xxx is a model name starting with [LBP].)
When the [Authenticate] dialog box is displayed
Enter the administrator's name and password, and then click [OK].
7. Close all open windows.
8. Restart your computer and empty the Trash Bin.
The printer driver is uninstalled.
Next, go to the imageCLASS LBP6000 - Drivers & Software page, and then download the file CAPT Printer Driver Ver.3.67 for Mac OS X 10.5/10.6/10.7/... listed under the [Recommended for You] section.
After installing the printer, please follow the instructions below to add the printer:
2. Click [+].
3. Click [Default], and then select the printer to be used from the printer list.
4. Select [Select Printer Software] from [Print Using].
5. Select the printer to be used from [Printer Software], and then click [OK].
6. Click [Add].
7. Make sure that the printer to be used is displayed, and then close the [Print & Scan] dialog box.