how do i clean the print head on my canon pixma mg3620 from my windows computer?

Use the printer driver utility. Procedure is specific.

Standard Cleaning:

1. Open the printer driver setup window.
2. Click the Maintenance tab. Click 'Cleaning'.
3. In the Print Head Cleaning dialog, select the ink group to clean.
4. With printer on, click 'Execute'.

Wait for process to finish. Print a nozzle check pattern.

If print quality remains poor: Perform Deep Cleaning.

1. In the Maintenance tab, click 'Deep Cleaning'.
2. Select the ink group.
3. Click 'Execute', then click 'OK' on the confirmation message.

If two Cleaning attempts fail: Use Deep Cleaning.

If Deep Cleaning fails: Turn printer power off. Wait 24 hours. Perform Deep Cleaning again. Do not unplug power cord when turning off.

If problem persists after second Deep Cleaning: Replace the FINE cartridge.