Geek hat on.
We bought an HP DeskJet 9800 at one of our sites for printing 11x17 paper. It also will do A3 size. It was not expensive, about US$300.
The prints look good. Prints with heavy graphics...where a lot of ink is being put on paper, is served well by heavier paper stock.
To watch for: HP makes their money is not on the printer, but on the toner cartridges that the printers use. A toner set is $50-60 and doesn't last very long. Laser print cartridges last longer and have less saturation concerns, but require bigger expenditures for the printer and the cartridges. You will need to buy cartridges with the printer, HP's starter cartridges will only last for a few pages.
This one needs some space...as will any that you buy of this size. The hopper can hold 11x17 paper, this printer has a larger footprint than what you may be accustomed to seeing.
If you will be largely using this for your Yudansha certificates, this may be a good investment for your school.
Something to keep in mind:
Do you have the office space to hold a printer this size, or will the extra bulk be a big hassle?
Lisa's suggestion of using Office Depot, Staples, Kinkos, etc. requires the least cash outlay. You can either e-mail over the files and have them printed, or bring a CD over and have them printed.
However, having a printer in house saves you the trip and the hassle. On the off chance that something goes wrong with the certificates, they get wet, or a name was unintentionally mispelled, you would have the capability to make reprints on the spot. You may find other uses too, such as signage that is more effective at the 11x17 size.
Geek hat off.
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