Brother MFC Scanner not recognized any more

I have a Brother MFC-1910W connected by WIFI (multi functional wireless b/w laser printer, scanner and fax). Since a few days I cannot use the scanner any more. In the first place the scanner icon was disabled so I decided to remove and add the printer. Since than the whole scanner icon disappeared as if the MFC has no scanner capabilities. I have Brother driver 4.0.5 installed. I found a scanner 4.2.0 on brother support site (sorry, page not available in english ). From that installation on I cannot connect using bonjour any more but using IP but still no scanner available. Now the best: Accessing from another MacBook (both running 10.13.2) there is no problem. It seems some printer driver installation or preferences are broken. Any idea how to fix, cleanup, whatever (maybe an option to reset all printer driver info would be fine)?