Check the following points to resolve the issue:
 

1. Perform the calibration using the Touchscreen or the printer driver.
   Click here to see the details of how to carry out calibration.
2. Adjust the copy density and contrast if you are copying.
3. Make sure Toner Save mode is off in the Touchscreen or the printer driver.
4. Make sure the media type setting in the driver matches the type of paper you are using.
5. Shake all four toner cartridges gently.
6. Wipe the laser scanner windows with a dry lint free soft cloth.