Flatbed printer mod

I have built a flatbed printer from an old Epson Stylus 640 but need to fool
the
printer into thinking there is paper in, when the drive stepper is disabled
I have tried timing relays but can't get it right. Does any clever person
know how I do this. Maybe some way of resetting the control chip

I have a good knowledge of electronics but can't find the relevant info.

This would be a great project if it were possible.
DH