HP 7550 Series Plotters - Paper is Ejected When Loading
Why the paper ejects out the back when attempting to load it.
There are two possible reasons:
The paper is not a standard size (A=8.5 x 11, B=11 x 17 inches, A4=210 x 297, A3=297 x 420). The paper will be ejected if it does not conform to these measurements. (The typical problem is that the paper is too short.)
The media sensor is out of calibration or broken. Try calibrating the media sensor by the doing the following:
Load paper manually.
Power the plotter on while holding down the ENTER and two (2) buttons simultaneously.
This will recalibrate the media sensor.
If the symptoms persist, the plotter needs to be serviced.
Ask the community!