i replaced the ink cartridges but my mg3620 still says it's out of ink and won't print.

Diagnosis

The Canon PIXMA MG3620 utilizes a "chip-based" ink monitoring system. When you install new PG-245 (Black) or CL-246 (Color) cartridges, the printer reads a small electronic chip on the cartridge to determine the ink level. If the printer continues to report that ink is empty, it is usually because the printer is still referencing the "memory" of the previous depleted cartridge, or there is a physical communication failure between the gold contact pads on the cartridge and the spring-loaded pins inside the print head carriage.

This issue is common when using "XL" high-capacity cartridges or third-party remanufactured tanks, as the printer's firmware may not automatically trigger the reset sequence. You can confirm this is a recognition error if the "Alarm" lamp (orange triangle) is flashing on the printer panel, specifically indicating Error Code 1688 (Ink cannot be recognized) or 1401 (Ink has run out), preventing any print jobs from initiating despite the physical presence of full ink tanks.

How to Fix It

To force the MG3620 to override the ink level monitor and recognize the new hardware, follow this precise sequence:

1. Power on the printer and ensure the power light is solid green.
2. Open the front cover to allow the cartridge holder to slide into the replacement position.
3. Locate the Stop/Reset button (the red circle with a triangle inside). Press and hold this button down for exactly 5 to 10 seconds. You will notice the printer making mechanical noises as it re-initializes the carriage.
4. While the printer is still powered on, remove the PG-245 and CL-246 cartridges.
5. Inspect the gold contact chips on the back of the cartridges. Use a lint-free cloth dampened with a tiny amount of isopropyl alcohol to gently wipe the gold pads to remove oils or ink residue.
6. Re-insert the cartridges. Push them upward and inward firmly until you hear a distinct "click" and the cartridge locks into place. If they are not seated fully, the pins will not touch the chip.
7. Close the front cover and wait for the printer to perform its initialization cycle. The "Ink Low" warning should now disappear, or the printer will allow you to bypass the warning and proceed to print.

If That Didn't Work

• Hard Power Cycle: Turn the printer off and unplug the power cord from the wall outlet. Hold the power button down for 30 seconds to discharge any remaining electricity from the capacitors. Leave the printer unplugged for at least 10 minutes before plugging it back in and restarting. This clears the volatile memory cache that may be clinging to the "Empty" status.
• Cartridge Swap Test: If you have another set of cartridges, swap them in. If the printer recognizes the second set but not the first, the chip on the new cartridge is defective (a "dead chip"), and you must request a replacement from the vendor.
• Clean the Carriage Pins: Use a flashlight to look inside the print head carriage where the cartridges sit. Check for bent or recessed gold pins. If a pin is bent, use a thin needle to very gently nudge it back into alignment so it can make a flush connection with the cartridge chip.
• Driver Reset: On your computer, go to the printer properties and remove the MG3620 from your device list. Restart the computer and re-add the printer. Occasionally, the "Ink Low" flag is cached in the Windows or macOS print spooler and needs a fresh handshake with the hardware.

Heads Up

• Avoid Generic Refills: Using non-Canon chips often triggers the "Ink cannot be recognized" error. If using third-party ink, you must hold the Stop/Reset button for 10 seconds every time you replace a tank to bypass the ink level monitor.
• Prevent Clogging: The MG3620 print heads are integrated into the cartridges. If you leave the printer unused for more than two weeks, the ink in the nozzles will dry, causing streaks even if the printer says the ink is full. Print one test page weekly.
• Avoid Over-Cleaning: Do not run the "Deep Cleaning" cycle more than twice in a row. This process consumes a massive amount of ink and can actually cause air bubbles to form in the print head, worsening the print quality.