I have been using Ubuntu with my Brother MFC-J6720DW printer/scanner/fax for some time. Printing seems to work all right. But Ubuntu regularly seems to forget that the scanning capability, which I do not use as much as printing, is there. (I never use the device for faxing.)

I have gone through the reinstall process four or five times over the past year. And I have tried to incorporate suggestions found on this AskUbuntu site. It is frustrating to have to go through this process over and over.

Each time, things get to the point where the scanner is working properly (originally attached through wireless network and then through direct USB cable, because I thought the wireless might be complicating things). For weeks, it continues to work through shutdowns and reboots. But, after awhile, scanning stops working. Trying Simple Scan results in the "Failed to scan - unable to connect to scanner" message.

I just gave XSane Image Scanning Program a try. It produced an error: "Failed to open device 'brother4:bus2;dev10': Invalid argument." I recall something about bus and dev settings in an answer to a post I followed with good results some months back. I thought things were finally resolved. Apparently not.

Does anyone know what's going on with Ubuntu and the scanner?

Are Ubuntu updates possibly undoing the changes that get the scanner to work?

Is there some way to secure the changes that work so they are not undone or maybe to preserve them and quickly/easily put them back in place when scanner stops working again?

ADDITION (17 Dec 2017): Did some checking on the Bus and Device numbers and found that they are dynamically assigned by Ubuntu. The scanner can be recognized by determining the new Bus and Device numbers through lsusb and then using chmod to change permissions for the new location. So, the focus of my question becomes: How can I have Ubuntu either assign static Bus and Device numbers so the scanner remains usable (without having to periodically go throguh the lsusb and chmod process) or have it recognize the new location of the usb scanner and keep it accessible.

  • 1
    so that is a brscan 4. I made some suggestions here askubuntu.com/questions/985983/… and I wonder if you have done them all; the Brother setup does seem tricky; Canon seem the easiest at present – pdc Dec 18 '17 at 2:09
  • Possibly, I did not do that final (udev rule) step, because the FAQ indicated it was for Ubuntu versions 10.10 through 13.10. The scanner has been working since my latest chmod. Will the udev rule thing allow Ubuntu to locate the dynamically assigned bus and device numbers for the scanner or will it prevent a change in the numbers? – Thomas Hunt Dec 19 '17 at 10:37
  • I would recommend installing the udev rule; I suspect Brother have not updated the website since 13.10 – pdc Dec 19 '17 at 21:10

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