It would be interesting to know if the mark rotates withthe page orientation...
I suspect this IS a printer issue of some sort. Does it go away if you export to PDF and print that? ID is not really great at direct printing, and HP printers are probably at the top of the list for printers that don't play well with ID when printing directly. Are you using the PCL driver or the Postscript emulation?
Mark stays the same (horizontal across a portrait page, vertical down a landscape page).
Exporting to PDF and printing that removed the issue.
Not sure with regards to PCL/Postscript emulation - how would I go about finding out?
I'm not very well versed in installing Mac printers, so I really can't tell you much about figuring out the driver. I don't see any drivers for Mac listed at all on the HP pages, so I suspect there must be some uninversal driver, like CUPS, in there someplace.
It's not unusual for users with HP printers to need to export to PDF for output as a matter of course.
Thanks, it's not the end of the world having to export before printing but just thought there may be an easy fix I'm overlooking. It is only a recent issue (printer is a year or so old, this began a couple of weeks ago) and I can't think what may have triggered it. I'll persevere with exporting for now, and maybe it'll fix itself when I next replace the toner!
I did see something regarding a power supply issue affecting the first page of print outs on certain HP printers (with a fix involving bending some pins with plyers) but reluctant to take my printer apart considering it's only affecting InDesign