printing on labels with lprint is far slower than with legacy rastertolabel filter from CUPS

[wt]

I am using lprint 1.3.1 on Fedora Rawhide.

I used LibreOffice to create a very small pdf
here.

I also converted it to a png
here

I added my printer via the web ui. I used the usb printer on my laptop and the
I use the following command to print 2 copies with lprint directly: lprint submit -d tester -n 2 print_test.png

There is a huge delay when doing this. The delays I see are roungly 10s before the lprint command returns, then 10s before the first page is printed, then 10s before the second page is printed.

For fun I also setup the printer in CUPS with the Generic IPP Everywhere driver. I then printed with this command: lp -d blah -n 2 print_test.pdf

Same issue as with lprinting the png.

I created the PDF from a LibreOffice doc, so I also tried to just print from LO writer directly. That experienced a similar delay as when trying to lprint the png.

These were all horrifically slow compared to setting up the printer via to older Zebra manufacturer with the Zebra ZPL Label Printer (en) driver which uses the older rastertolabel filter. I say the DPI to 203 and the media size to 4x6. That older driver prints nearly instantaneously when trying to print the pdf or when printing directly from LO. Is there anything that I can do to reduce all the delays I am seeing while using lprint to print to my label printer?

Just so you know, I print hundreds of labels with the older rastertolabel system to use when packaging baked goods for my bakery. I would love to update to lprint, but it's untenable with a 10s wait between each label printing.

As some other tests to rule out my hardware as the problem, I also did the following:

The test print from the lprint web ui also seems to take a number of seconds to print, though it does seem a couple seconds faster than any of my lprint trials above though I don't have an accurate way to time the difference.

I also tried converting the png manually to ZPL, I wasn't successful on that, but I did print some ZPL example labels by catting directly to /dev/usb/lp0. That went nearly instantaneously.

Given the speed of the cat ZPL test and the old filter driver test, I am pretty convinced this is not an issue with my printer or other hardware being slow.

I'm happy to try pretty much anything to make this work better if you have any suggestions. Thanks!

[michaelrsweet]

What model printers are you using?

How are the printers connected?

What version of CUPS are you using?

Are you using the lprint package from Fedora or compiling from source?

[wt]

In the order requested...

I have tried two separate printers.

• Arkscan 2054A
• HP KE100

Both of these printers are ZPL printers. The Arkscan 2054A is 203dpi, and the HP KE100 is 300dpi. I tried the basic workflow (printing a 4x6 doc from libreoffice writer) and hadsimilar experiences with slow speed like I described in the intial report on both. However, for the initial bug report, I only meticulously ran through and documented my setup/testing on the Arkscan. I wasn't as meticulous about repeating on the HP since the slowness for the normal case seems to be very similar to the Arkscan setup.

The printers are both connected via direct USB connections.

Cups version: I am running the latest packages from Fedora Rawhide. This appears to be cups version 2.4.11. Here's a list of all the rpm packages I could find in case the specific package versions matter.

➜  ~ rpm -qa | grep cups
python3-cups-2.0.4-3.fc41.x86_64
cups-pk-helper-0.2.7-8.fc41.x86_64
cups-filters-2.0.1-1.fc42.x86_64
cups-filters-driverless-2.0.1-1.fc42.x86_64
gutenprint-cups-5.3.4-18.fc42.x86_64
bluez-cups-5.79-1.fc42.x86_64
libcupsfilters-2.1.0-1.fc42.x86_64
cups-browsed-2.1.0-1.fc42.x86_64
cups-filesystem-2.4.11-9.fc42.noarch
cups-libs-2.4.11-9.fc42.x86_64
cups-client-2.4.11-9.fc42.x86_64
cups-2.4.11-9.fc42.x86_64
cups-devel-2.4.11-9.fc42.x86_64
cups-ipptool-2.4.11-9.fc42.x86_64
cups-libs-2.4.11-9.fc42.i686

Lprint version: I am using lprint from the package. Appears to be version 1.3.1, which appears to match the latest tag I see on the github repo as well.

➜  ~ rpm -qa | grep lprint
lprint-1.3.1-9.fc42.x86_64

[wt]

Is there any way to output whatever ZPL is sent to the printer to a file?