# ADR 012: CUPS for the unsupported printer

- HTML version: https://robbiepalmer.me/projects/homelab/adrs/012-cups
- Project: Home Lab (https://robbiepalmer.me/projects/homelab.md)
- Status: Accepted
- Date: 2026-08-02

# Context

I own a 2011 Canon MX3100 printer. Canon no longer supports it — the vendor
would have me buy a new printer — but the hardware still works, so the plan
is to avoid ewaste by keeping it in service with free software.

My own experience with the open-source route: it printed fine from an old
Ubuntu 18 setup, but not from Ubuntu 22+ or from macOS, and I couldn't test
Windows because I don't have a Windows machine. I wasn't willing to keep a
box running Ubuntu 18 just to hold drivers — it's end-of-life.

That points at the Raspberry Pi as the host. Linux is where these open-source
drivers are actively maintained: Gutenprint formally deprecated macOS support
in 2024 and no longer produces binaries for modern macOS, while on Linux it's
the standard driver set. The Pi is always on, already part of the lab, and
can run a print server that every device on the network reaches. I also want
to print remotely from my phone — the classic case where a print server
shines.

# Decision

Install **CUPS** on the Raspberry Pi and connect it to the Canon MX3100 via
its (USB) connection, using **Gutenprint** — the open-source driver suite for
Canon, Epson, and others — to bridge the gap left by Canon's dropped
support.

CUPS exposes the printer over IPP to the whole network, so the Mac, phones,
and other devices print to it as a network printer. Remote printing works over
the tailnet, and the Pi keeps the printer alive independently of any one
device.

# Alternatives

## Buy a new printer

* **Pros**: Modern drivers, no tinkering.
* **Cons**: Unnecessary spend; discards working hardware. Exactly the ewaste
  this lab exists to avoid.
* **Decision**: Rejected. The MX3100 still prints.

## Run the printer off the Mac mini instead of the Pi

* **Pros**: The hub is already always-on.
* **Cons**: Puts the printer (a hardware peripheral) on the same box as the
  photo backup and agent stack; a hub reboot takes printing with it.
* **Decision**: Rejected. The Pi keeps the lab's responsibilities separated
  and redundant.

## Keep the printer on an old machine with vendor drivers

* **Pros**: Vendor-native drivers.
* **Cons**: Keeps a dedicated old machine alive just to hold drivers; CUPS
  with a generic driver does the job on hardware already in the lab.
* **Decision**: Rejected. More ewaste, more power draw, more maintenance.

# Consequences

### Pros

* **Working hardware stays working**: the MX3100 prints again, no new
  hardware purchased.
* **Network + remote printing**: any device prints via IPP; remote printing
  works over the tailnet from the phone.
* **Redundancy preserved**: printing is decoupled from the Mac mini hub.

### Cons

* **Generic-driver tradeoffs**: some printer-specific features (scanning
  niceties, vendor utilities) may not work through the generic path.
* **A service to maintain on the Pi** alongside AdGuard Home and Netdata.
* **Physical dependency**: the printer still needs USB to the Pi, so it must
  live near the Pi.

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