My iOS device is unable to print on double sides

[master-ang]

My printer supports automatic duplex printing, but I cannot achieve duplex printing with my iPhone 13 and iPhone X. In the iOS print settings, I can select "Double Sides Printing," but when I press the print button, nothing happens. However, if I cancel duplex printing, it prints successfully. Additionally, my Android phone, Windows computer, and Mac can all print on both sides successfully, only the iOS devices cannot. How can I resolve this issue?

[master-ang]

My iPhone 13 does not have a duplex printing option, while my iPhone X does have the option but is unable to print.

[master-ang]

i found this：
https://discussions.apple.com/thread/255283321?sortBy=rank

[DrPsychick]

That link is interesting, because the answer links to a tutorial that basically shows how to install cups - exactly what this container does: https://discussions.apple.com/thread/255283321?answerId=259838859022&sortBy=rank#259838859022

So my best guess is to set duplex by default in the printer when setting it up with cups. Or have two printers configure (with same destination, if that works), one with duplex and one without? Does that help you?

[master-ang]

I think this issue is likely caused by the iOS 17 update. I've been using it for a long time without any problems before. My printer model is quite old; it's the HP LaserJet 1320 series. I've continued to use it because its automatic duplex printing feature works very well. It seems that the iOS 17 update has upgraded the version of AirPrint, which is incompatible with the old driver of the 1320 model. I've tried all the 1320 drivers in your software and set the default to duplex printing, but none of these solutions worked. After upgrading my iPhone 13 to iOS 17, the duplex printing option simply doesn't show up. However, it's quite strange that my iPhone X, which only supports up to iOS 16, can display the duplex printing option but still can't print. Do you know where I can find a newer printer driver? I'd like to try manually updating the printer driver.

[DrPsychick]

I no longer use my own creation, because I have a new printer that supports AirPrint directly. This one (Brother DCP-L3550CDW) does show duplex printing on an iPhone 12 with iOS 18.

I fear it might be indeed the AirPrint support/version in this container. The script was taken from a dead repo, so we would need help from the community to understand and update it: https://github.com/tjfontaine/airprint-generate

[master-ang]

Thank you for your analysis and response. I believe you are correct. It is likely not due to a specific printer driver, but rather the version of AirPrint supported by the container, which makes it difficult for me to resolve. Do you have any solutions? Can you try to take action?

[DrPsychick]

Since I'm unable to test it, can you try an build an image with some adjustments to https://github.com/SickHub/docker-cups-airprint/blob/master/airprint/airprint-generate.py?

Try adding <txt-record>Duplex=T</txt-record> around line 58, I would guess that may hardcode Duplex to True. Alternatively edit the generated AirPrint file in your running container and kill -HUP the cups process, I guess that should work by reloading the config.

If that works, we can figure out how to make it configurable.

[master-ang]

I really want to do this, but my ability is limited. I can hardly understand these codes, and I don't have the prerequisite knowledge to know how to build image. I only have a QNAP NAS, from which I can pull images from the hub for installation and testing. Thank you for your exploration. I look forward to you or other experts like you creating an image, and I can help with the testing. I believe this can help all users who are using iOS 16 and later versions.

[DrPsychick]

Would you like to do it together? Because it will be difficult if not impossible for me to test.
If so, send me an email (see my profile) and I'll send you an invite to my slack where we can meet to chat and screenshare to resolve the issue. What do you think?

[master-ang]

OK，i'll try my best.

[DrPsychick]

I had an idea how you can test it easily. I built a docker image with <txt-record>Duplex=T</txt-record> hardcoded, please give it a try and let me know if that enables duplex print for you. https://hub.docker.com/layers/drpsychick/airprint-bridge/duplex/images/sha256-a6d47ad361d58b60b2513178a4fc40f95f17cf69799a68624667e268a18bf760

If it does, I can open an issue with more detailed explanation and could start working on it when I find the time (or someone else).

[master-ang]

It still doesn't work. I can see the duplex printing option on my iPhone X, but after clicking print, there's no response both the iPhone X and the printer, and docker-->CUPS-->“Jobs” doesn't receive any tasks.

If I don't select the duplex printing option, CUPS-->"Jobs" will receive task
and shows:
“processing since
Fri Jan 17 20:48:01 2025
"cfFilterChain: universal (PID 2131) exited with no errors."
“
The data light on the printer will flash, and the iPhone X will display a print page showing the "printing..." status, After the transfer is completed, the printing is successful.

I searched online and it appears that after the iOS upgrade, a newer version of the printer driver is needed. I believe the problem is likely not with CUPS, but rather the printer driver hasn't been updated for quite some time and is no longer compatible.

Unless CUPS can "translate" the printing requirements of the new iOS version into a format that the old printer driver can "accept".

[DrPsychick]

I'm sorry to hear that :(
That means we have to go deeper and need to understand the change in the protocol or at least better understand how that script makes printers available with options via AirPrint.

At the community out there: we would really appreciate your help to understand and improve the airprint-generate script.

There seem to be a lot of forks with lots of improvements around, so maybe we'll get lucky and someone already has a patch fot this issue: https://github.com/tjfontaine/airprint-generate/forks?include=active&page=1&period=5y&sort_by=stargazer_counts

[master-ang]

I found these:
tjfontaine/airprint-generate#5
https://www.finnie.org/2010/11/13/airprint-and-linux/
https://discussions.apple.com/thread/250663855?sortBy=rank