Ytdyklly

This problem has been around since Trusty. I'm still getting nowhere using Ubuntu 16.04 64 bit on 2 computers: one upgraded from Trusty and one with a fresh install. lsusb sees scanner: Bus 001 Device 002: ID 04a9:2220 Canon, Inc. CanoScan LIDE 25 "sudo sane-find-scanner" sees scanner: found USB scanner (vendor=0x04a9, product=0x2220) at libusb:001:002 "sudo scanimage -L" sometimes sees scanner: deviceplustek:libusb:001:006' is a Canon CanoScan LiDE25 flatbed scanner`. I have tried amending plustek.conf in /etc/sane.d by adding the 2 lines:

[usb] 0x04a9 0x2220 

device /dev/usbscanner

This answer is intended to guide OP for troubleshooting on own, since other relevant information provided by OP were found scattered on Ask Ubuntu, Ubuntu forums and Launchpad (For some reasons, OP didn't bother to note these in the question).

Troubleshooting

Most users failed to note the most important information: the changing point.

In this case, the changing point is the answer to the only question: "What are the changes made to the computer or scanner, since last time the scanner was working well on Ubuntu?"

If one fails to provide any answer for above, then one has to follow the tedious way to troubleshoot by considering each and every possible factors that may have caused the scanner to fail.

From most obvious to most tricky factors to consider:

• Is the scanner broken? (Test on other operating system i.e. Windows or other Linux distro, with different architecture i.e. 32-bit, 64-bit)




• Does the USB cable work? (Test with other USB cable, try with shorter cable i.e. 1m or less)




• Is the scanner connected directly? (Using USB hub could prevent the scanner from being detected)




• Is the scanner connected to a functional USB port? (Some options in BIOS/EFI menu could accidentally disable USB port from functioning normally; This is hardware dependant)




• Is the host machine having sufficient voltage supply to USB ports? (Check capacity of power supply unit, nominal voltage in BIOS/EFI, etc.)




• Has the host machine installed/upgraded any hardware parts? (Some hardware i.e. USB controller interface has higher priority for front/back ports)




• Has the host machine installed/upgraded any hardware drivers? (Possible conflicts between multiple printer/scanner drivers)




• ...and other factors that I might have missed.

Misleading sense

To this date, Canon CanoScan LiDE 25 still works well. When the scanner is plugged into the USB port, it is detected automatically and user will just have to run GUI scanning program to use it. No further configuration is needed. It works out of box.

For me, the scanner has been working well since Ubuntu 8.04 32-bit (XSane), followed by 10.04, 12.04, 14.04 32-bit and 16.04 32/64-bit (Simple Scan). I have used interchangeably between five different computers. The oldest machine I am running now is 8 years old.

My point is, just because the scanner had stopped working, that doesn't necessarily mean the problem lies in the scanner or host system.

The reason could be something else, albeit trivial, which had caused the scanner to fail. If one had to edit configuration file and run some commands to make an 11-year old scanner to work on Linux, in year 2016... Something is not right. That doesn't make any sense to me.

I can only suggest to recall the changing point, or start troubleshooting one by one by asking above questions to yourself. I hope you will find the solution, since existing answers are not useful to you.