printer quota?

I use a raw lpd printer queue to a GDI USB printer from Win* clients, hosted on Suse 8.3 by Samba. Works a treat, except for very large print jobs (e.g. large high resolution color images) the printer stops about half way through. Quota is off, harddrive and memory plenty. I digged through doc and conf and fail to find any size limitation on queued print jobs. Any thoughts? TIA, Bernd