Jim <jb...@cfw.com>

I have salvaged a lot of HP Deskjet printers lately, and have come on a part
in all that I would like more information on.  It is obviously a print head
position sensor, and looks somewhat like a wide photo-interrupter.  It is
located inside the print head/cartridge carrier.......the part that moves
back and forth when printing......and has an optical interruper strip that
runs through it.

Most have part numbers like Q9874 and Q9864, the HP logo, and the part has 4
leads, a lens, etc.

Is this a quadrature detector/direction decoder or just simply a
photo-interrupter?  I can't seem to find a data sheet or any other info on
this part.  If it is a quadrature direction decoder, I would like to know,
'cause I have a project where I would like to use it.

Thanks