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🐛 Bug Report / Connectivity Issue¶

Component: Network Services - AirPrint/Bonjour Discovery
Device: Canon PIXMA G7020 Series (Reported on various models)
Operating System: macOS (Ventura 13.x, Sonoma 14.x) / iOS (16.x, 17.x)

Summary¶

Intermittent or complete failure of AirPrint functionality for designated Canon printers following the last firmware update (v1.0.15) or recent OS updates. Printers are visible on the network via IP address but fail Bonjour service registration, leading to printers disappearing from the "Printers & Scanners" list and "Print" menus. A temporary fix is often achieved by power-cycling the printer, but the issue recurs within 1-12 hours.

Steps to Reproduce¶

1. Ensure the Canon printer is connected to a standard Wi-Fi network (2.4GHz band tested; 5GHz also shows issue).
2. Ensure the host device (Mac/iPhone) is on the exact same subnet/SSID.
3. Wait until the printer is idle/asleep (approx. 15 minutes).
4. Attempt to print any document from a macOS or iOS device.

Expected Result¶

The Canon printer should be immediately available in the print dialog via its 'Bonjour Service Name' (e.g., Canon G7020 series._ipp._tcp). Printing should commence without manual intervention.

Actual Result¶

The printer either:

1. Does not appear in the list of available printers, forcing the user to manually add it via IP address (which often fails after a short time).
2. Appears in the list, but selecting it yields an error: "Printer is not responding" or "Could not communicate with printer."

Analysis & Potential Root Cause (Developer Notes)¶

• Bonjour/mDNS Service Lifetime: The time-to-live (TTL) for the Bonjour service appears to be expiring prematurely, or the printer stops rebroadcasting the service after entering a low-power/sleep state. The service advertisement seems to drop or become invalid until the printer is manually woken up or power-cycled.
• Firmware Conflict: The issue correlates directly with Canon Firmware version v1.0.15. Downgrading the firmware restores AirPrint stability.
• IPP Port Issue: Initial connection seems to use the standard IPP port (631), but the service discovery heartbeat seems broken.

Suggested Fixes/Next Steps¶

1. Investigate Canon firmware updates for a hotfix that addresses Bonjour packet integrity/broadcast frequency on sleep/wake cycles.
2. Implement a persistent manual Bonjour announcement override command in printer configuration (if accessible via a hidden service menu).
3. Verify if disabling the "Auto Sleep Mode" on the printer resolves the issue (currently being tested, but is an undesirable user experience).