I wanna update Canon laser printer driver LBP6000 which is compatible with OS El Capitan?

Hello there m. rahim,

It sounds like you are looking to update your printer drivers because it does not seem to be working correctly after you updated to El Capitan. You can check for any available updates using the Mac App Store:

Make sure you have the latest software

If your printer doesn’t support AirPrint, make sure you have the correct version of your printer’s software (also called its printer driver).

• If you’re using a printer that another user is sharing, make sure you’re both using the same version of the printer software. To find out which version you’re using, open Printers & Scanners preferences (choose Apple menu > System Preferences, then click Printers & Scanners). Select the printer in Printers & Scanners preferences, click Options & Supplies, then click General. Note the driver version.

• If you’re using a network printer or a printer connected to your Mac, make sure you have the latest version of the software for the printer. If you still have problems, try different printer software for your printer.

From: Printing troubleshooting - Mac Help

The same link also contains printer troubleshooting in general that I would recommend that you use if there are no updates and the issue persists

Thank you for using Apple Support Communities.

You're very welcome!

Canon has released the CAPT v3.80 driver to support El Capitan. Before installing this driver it is recommended that you remove the LBP6000 from Printers & Scanners. Then open Finder and select the Go > Go to Folder menu. Then enter (or copy and paste) the following text and then press the Go button.

/Library/Printers/Canon

In this Canon folder you should see the previous CUPSCAPT folder. Trash this folder and then restart the Mac. Once you have logged back in to the Mac, run the new CAPT v3.80 driver installer and then add the LBP6000 in Printers & Scanners.

After upgrading to OS X El Capitan, Canon LBP 6000 won't print