Printers, printers, printers…

They have been there from the dawn of time (ie since 1970, obviously), and still, I can’t help but find fascinating how they still are among the most unpredictable computer peripherials.

I’d have thought that by now, they would have been mastered, but no.

That’s why when I decided that I actually needed a printer for myself, knowing that I had to play the “Configure your printer” game in hard mode (‘cause you know, printing devices vendors usually don’t care about Linux), I wasn’t really optimistic about it ending well. To say the least.

Personal specs for my personal printer

So, before even starting to look for a specific device, let’s decide exactly what I want. I thought about it a bit, and came up with the following list :

  • It has to print :

    Pretty obvious, but it would be stupid to forget it, wouldn’t it ? Even refining this point a bit (color printing, reasonable quality, etc…) doesn’t really narrow your research down. Everything you can possibly find usually has it.

  • It has to scan :

    That’s a pretty common one too. I’d be happy with a simple flatbed scanner (I can always assemble scanned documents afterwards), but a model with an Automatic Document Feeder would be a nice addition for bulk scanning.

    Not mandatory, though.

  • If inkjet, it needs to have refillable ink cartridges :

    I’m not gonna be printing a lot, and in these conditions, it’s probably not worth to go laser or anything more fancy than inkjet. And since many types of widespread printers can be recharged by yourself quite cheaply for the same result than official cartridges…

  • It needs RJ-45 (wired Ethernet) connectivity :

    USB is good, but I want to be able to both print from various devices, with various connectivity, from various places in my flat, and, most importantly, without needing to move my ass whenever I want to do so.

    This leads us to a network-connected printer, but that’s not enough. I don’t want Wi-Fi, for several reasons.

    First, I prefer to connect everything that can be with cables. Better bandwidth, better stability, more Wi-Fi bandwidth available for devices that actually need it…

    Also, I’ve had a terrible experience in the past with a Wi-Fi connected scanner, that would just randomly stop scanning in the middle of a document, unless you plug it with RJ-45. Bad reception and poor protocol or implementation, I guess. Not happening again.

    Finally, although it’s possible to plug USB to a network-connected machine, and install a print server such as CUPS, that tends by experience not to be as trivial as one would like, and it would be silly not to try to have out-of-the-box support if I can.

  • It needs Linux support :

    That was always gonna be the toughest bullet point to fill.

    Even officially supported OSes still regularly run into issues with printers, and there’s only community support on Linux.

    If possible, out-of-the-box working printer with almost 0 configuration would be perfect, especially if it works for networked operations. But honestly, that’s probably way too much to ask for.

Overall, that leaves us with a pretty tough set of specs to match.

Ahead-of-time research

That bit was depressing.

Asked a few friends and on a few channels with other tech people, basically, the answer was “Yeah, you can never be completely certain before trying. HP seems to work fine, overall, though.”

Also tried various sites such as Openprinting, but even then, I was feeling like I was still gonna have to guess.

Buying : the leap of faith

Months went by like that, just thinking “That sucks, I’m not sure what to do”.

Finally just went to a big shop for computer-related stuff, asked the seller if they could tell me about Linux support (obviously, they could not), annoyed him with extra questions, etc…

In the end, they would take it back for 2/3 of the original price even if the ink cartridges had been opened, so, after some research on this exact model (HP OfficeJet Pro 8719), on my phone, in the middle of the shop ; here I am, going back home with a huge cardboard box. (At least it has handles)

First setup

Well, to put it bluntly, it kinda just worked.

I almost couldn’t believe it.

I just put the ink cartridges, plugged it to power, USB, wandered through the default printer GUI (probably Gnome’s).

Unplug USB, plug RJ-45, re-add printer through CUPS web interface. Boom, works. Had to guess between the different options which one was correct, but hey, trial and error between 3 options is not exactly an advanced use !

Extra playing with SANE and scanning

That was too good to last, I guess.

I’m not certain what exactly I did that broke my perfect setup, but it broke. Most likely when I tried to change the name announced by the printer in the varions autodiscovery protocols.

I was able to reconfigure printing, just as before, but not scanning. simple-scan would now only detect my laptop’s webcam.

Yeah, annoying.

So, I started digging.

Apparently, scanning is mostly done on Linux through the SANE API. This is the API used by (among others) simple-scan to communicate with the scanner.

First of all, USB scanning was still working, and network printing too. So, not a network issue, and likely not a SANE driver (or something) issue.

More likely, it was a network service discovery issue.

However, to this day, I’m still not certain about how network discovery works. I initially thought of some mDNS/Avahi black magic, and there indeed were various scanner-related entries in the output of avahi-discover, but that wasn’t of any use to diagnose why this wouldn’t work anymore.

At this point, I was pretty lost, and tried various stuff recommended here and there, which included fiddling with config files in /etc, hand-crafting SANE URIs… All of that basically blind since I couln’t find any useful logs.

In the end I gave up, and came back at it a few weeks later.

This time, I quickly ended up where I should probably have started my research : the ArchLinux Wiki, and more specifically, a page about troubleshooting specific printers.

Ok, so, I finally have a sane way to find the SANE URL of my scanner : hp-makeuri

$ hp-makeuri 192.168.0.15

HP Linux Imaging and Printing System (ver. 3.19.6)
Device URI Creation Utility ver. 5.0

Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

CUPS URI: hp:/net/HP_OfficeJet_Pro_8710?ip=192.168.0.15
SANE URI: hpaio:/net/HP_OfficeJet_Pro_8710?ip=192.168.0.15
HP Fax URI: hpfax:/net/HP_OfficeJet_Pro_8710?ip=192.168.0.15

Done.

# By the way, simple-scan has a -d flag to get debug logs
$ simple-scan -d 'hpaio:/net/HP_OfficeJet_Pro_8710?ip=192.168.0.15'

Aaaaand that worked just fine.

That’s good, and a viable workaround, but I need to pass this argument everytime (I tried, the detection didn’t just get magically fixed in the process). It was nice to have it working with literally zero conf. Can’t we just fix it ?

Let’s try out the other commands on this page : hp-setup -i (I used the -i because I was too lazy to install the dependencies required to have a working graphical interface. Also, CLI is cool !)

This one walked me through various configuration setups for printer, fax, etc… but nothing scanner-related.

It did however fix my simple-scan, which now works as expected.

/facepalm

I also discovered that hplip is actually an hp-maintained official Linux library for interacting with printers. I previously thought it was community-maintained just like most brands.

Conclusion

To this day, I have honestly no idea how this got fixed.

Maybe the scanner-finding heuristics use your configured printers to look for scanners ?

I guess I’ll never know unless it breaks again, I’m done with this topic for now :)

Anyway, we might want to remember a few gotchas from this story :

  • The printer ecosystem is actually getting better ! Even though I’m not sure we’re ever gonna get guaranteed proper zero-conf setups.
  • The Arch wiki rocks ! As always.
  • HP actually has official linux support through an official library