filled the ink tanks but now it's leaking blue ink inside the printer

Diagnosis

This issue typically occurs when the ink is overfilled beyond the upper limit line or when the ink is poured too quickly, causing air bubbles to trap ink in the ventilation channels. The Canon PIXMA G7020 uses a vacuum-pressure system to move ink from the MegaTank reservoirs to the print head. If ink enters the air vent channels—the small gaps designed to let air in as ink goes out—it creates a siphon effect. This disrupts the pressure balance, forcing excess cyan ink to leak out of the tank seals and pool in the bottom of the printer chassis. You can confirm this by checking the ink level indicators on the front of the tanks. If the ink level is above the maximum fill line, or if you see ink clinging to the underside of the rubber tank caps, the seal has been compromised. Additionally, if you notice "beading" of ink around the tank's plastic rim, it indicates that surface tension was broken during the refill process, allowing ink to migrate into the internal cavity of the printer.

How to Fix It

Follow these steps precisely to stop the leak and prevent permanent damage to the electronic components of the G7020:

1. Immediately power off the printer and unplug the power cord from the wall outlet to avoid short-circuiting the main board if ink reaches the electronics.
2. Open the scanning unit/cover to access the ink tanks. Use a high-absorbency lint-free cloth or heavy-duty paper towels to blot up all standing blue ink from the bottom of the printer tray. Do not scrub, as this can push ink deeper into the chassis.
3. Carefully remove the Cyan ink tank if your specific regional model allows for tank removal; if the tanks are integrated, use a syringe to carefully extract any ink that is above the upper fill line.
4. Remove the rubber tank caps. Use a dry cotton swab to clean the rim of the tank and the underside of the rubber seal. Any ink residue on the seal prevents an airtight lock, which is critical for the vacuum system.
5. Inspect the air vent holes (the small apertures near the caps). If ink is pooled here, use a vacuum or a dry swab to clear it. The vent must be completely clear of liquid for the pressure to equalize.
6. Re-seat the rubber caps firmly, ensuring they "click" or sit flush against the plastic.
7. Plug the printer back in and perform a "Nozzle Check" print to ensure the ink flow has stabilized.

If That Didn't Work

• Perform a System Cleaning: If the ink is still leaking slowly, the internal pressure may be unbalanced. Go to the printer menu: Setup > Maintenance > System Cleaning. This process uses a significant amount of ink to purge the lines and reset the pressure, which often stops siphoning leaks.
• Inspect the Ink Tubes: Open the cover and look at the translucent ink tubes leading to the print head. If you see large air gaps or "bubbles" mixed with the blue ink, the vacuum is broken. You may need to run a "Ink Flush" (found in the Maintenance menu), though be aware this consumes a large portion of your ink tanks.
• Check for Tank Cracks: Inspect the plastic walls of the Cyan tank for hairline fractures. If the tank was squeezed or dropped during the refill, a micro-crack can allow ink to seep out under the pressure of the ink's own weight. If cracked, the tank assembly must be replaced.
• Clean the Absorption Felt: If the ink has leaked into the bottom waste pads, you may see "Ink Low" or "Waste Ink Full" errors soon. Use a vacuum with a narrow nozzle to remove as much liquid ink as possible from the bottom of the unit before it soaks into the internal sponges.

Heads Up

• Never fill the ink tanks past the upper limit line; overfilling is the #1 cause of leaks in the G7020 series.
• Always ensure the printer is on a perfectly level surface. If the printer is tilted, the ink will pool on one side of the tank, causing the air vents to flood.
• Avoid using third-party "compatible" inks that have a different viscosity than genuine Canon ink, as thinner inks are more prone to siphoning and leaking through the seals.
• When refilling, pour the ink slowly down the side of the tank to avoid creating air bubbles and foam, which can displace ink into the ventilation channels.