I have read your post and understand that you have print quality issues on the printer and wish to fix it. I will definitely help you.
To initiate the internal cleaning mode, you will need to follow the steps mentioned below.
Open the HP Color LaserJet CP1210 Series Toolbox. See View HP Color LaserJet CP1210 Series Toolbox on page 43.
Click the Help folder, and then click the Troubleshooting page.
In the area for Cleaning Mode, click Start to begin the cleaning process.
The product processes a single page and then returns to the ready state when the cleaning process is complete.
If in case, you are unable to access the cleaning mode on your printer through PC software, then it might be a driver issue and I request you to reinstall the driver using the latest driver from the link below.