What Is The Largest Flatbed Scanner Size How Can I Extend The Size Of My A4 Flatbed Scanner?

How can I extend the size of my A4 flatbed scanner? - what is the largest flatbed scanner size

Hello everyone,
I want my analysis of the "use scan" a large number of printed images and wondered if there is a way to adjust the scanner, I noticed a strip of rubber that the sensor can be analyzed by the size of an A4 sheet. Is it possible to open the case to replace and extend the rubber band (of one plus one) to scan more images or more?

Thank you very much

Elso