i have two computers connected to each other with a netgear switch and a printer (HP 5550) also for the two computers, problem is it will on print one job at time, and errors out, you can select any amount of copies to print it will only print one copy
The printer it plugged into the switch with Cat 5 cabling, the two pc's dont show any errors in logs because its the printer that is erroring out, i believe because it cant receive or hold more then one copy to print per job
I've never seen an issue where multiple copies can't be printed having to do with the printer holding jobs, even cheap inkjets. You can change the print setting if you want to test it, just tell the print driver not to spool jobs right away.
Try a firmware update on the Printer, check for new drivers for it (or maybe even try older drivers).