Fail to print with a USB-connected Brother QL-700

[tvanesse]

I am able to add the printer but there is no specific driver for this model (QL-700) so I can pick the QL-800 or QL-650. Both options fail anyway when I try to send a printing job to the printer.
The error is seen on the printer itself (blinking red LED) but the logs of ghostscript-printer-app don't say much.

Trying to use CUPS (no ghostscript-printer-app) to install the printer with the PPD file provided by Brother for the QL-700 works fine. But it fails as soon as I send any printing job. Although I'm getting more info from /var/log/cups/error_log:

W [29/Dec/2022:21:47:51 +0100] [Job 120] Grayscale/monochrome printing requested for this job but Poppler is not able to convert to grayscale/monochrome PostScript.
W [29/Dec/2022:21:47:51 +0100] [Job 120] Use \"pdftops-renderer\" option (see cups-filters README file) to use Ghostscript or MuPDF for the PDF -> PostScript conversion.

I tried every option below as well:

$ lpadmin -p QL-700 -o pdftops-renderer-default=pdftops
$ lpadmin -p QL-700 -o pdftops-renderer-default=mupdf
$ lpadmin -p QL-700 -o pdftops-renderer-default=hybrid
$ lpadmin -p QL-700 -o pdftops-renderer-default=pdftocairo
$ lpadmin -p QL-700 -o pdftops-renderer-default=acroread

with no success for any of them.

I also followed the development in this thread regarding a possible bug between the Brother driver and cups-filters, but that didn't help as I am not able to downgrade cups-filters on my machine.

I am running Ubuntu 22.04, CUPS 2.4.1 and ghostscript-printer-app 1.0.

I should finally mention that this particular printer with the exact same driver used to work just fine before a system upgrade. If only I could downgrade CUPS, I've got the feeling it could solve the problem.

[tvanesse]

brother_ql700_printer_en.zip
Here is the PPD file provided by Brother.

[tvanesse]

Update: I found a way to downgrade cups-filters to 1.27 and...it worked! I am able to use the printer again.

So I guess this is most likely an issue with cups-filters. Is their a way to transfer this Issue to https://github.com/OpenPrinting/cups-filters ?

[tvanesse]

I talked too fast. After rebooting, the printer will no longer print.

Can't remember where I first read this quote but, in this instance, I think it's just spot on:

Rage Against the Machine never specified what type of machine the band was furious with, but I reckon it was probably a printer.

[Zepmann]

Is this issue still relevant since lprint exists? It includes experimental support for the Brother QL-series of label printers, including the QL-700.