Optocoupler from InkJet printer(lexmark)

[tos]

I've gutted a low-end z612 lexmark printer the other day an as far as I can tell it uses the somple electromotor in conjuction with a optocoupler reading from a film strip. The markings on a strip are small. About a 5 binary 1-0 pairs are fitted in 1mm which makes it a hi-res way of reading position.

Anyway, the optocoupler has emitting LED (two wires) and on the other end 4 wires where, from what I've seen on the traces, only one is GND. Also, when exposed to incandescant light, all three pins seem to have voltage > 0.

Has anyone the idea how this OC works?

[Sasha]

I collected some of those optocouplers and stripes myself thinking of experimenting with it. I never did some experimentations but I guess on the other part should be 2 photo transistors as 2 contacts in encoder so it should be pretty easy to hook it onto DIN. I tested some single interrupt optocouplers from printers and they work fine. Maybe yours are broken.. :-\

[tos]

Hehe...superheating does wonderous things to electronics.

Tnx for reply.

[Sasha]

;D ;D ;D