I received some opamps today (TI TLC2272), and a friend of mine whom printer is not as defectiv as mine printed a picture I gave him and.... it works !
Well, at least I could read the strip. I would need to read the opamp output at faster rate to be sure there is no false 0 or 1 that the mcu would read during transitions, but when pulled with an arduino, the result is clean !!
(if you ask, 'B', 66 decimal, is 42 in hexa ;) )