I feel your pain.  I've used HP's since 1995 when Postcript Level 2 was first introduced.  I found and still find that 4-color inkjets will have difficulty matching Pantone spot colors.  There is a big difference between a printing press and an inkjet printer.  For very technical reasons I won't get into here.  You will have better quality proofs if you go with an Epson Pro or an HP Designjet mated with a Postscript 3 RIP.  The RIP is really the key to getting the printer to match Pantone spot color consistently.  That and the paper they use.  There are three levels of inkjet printers out there: consumer, photographer, and graphic arts.  You will be happy with ( not sure how big you want to print ) either the Epson Stylus Pro 3880 with an efi RIP or Colorburst or the HP Designjet 130 with an efi RIP.

Depending on what you mean by large format printer. I got this one:

http://www.staples.com/HP-Officejet-7500A-Wide-Format-e-All-in-One-Pri nter/product_894564

I just graduated college in graphic design and I needed a printer that would be able to do 11" x 17" with bleed. This one prints, according to the tech information, 13" x 44". Finding paper is kinda hard because the only standard size that is relatively close is 13" x 19" paper that I can find in the photo section. Staples has their brand that runs about $25 for 20 sheets. Also, if you do buy one from staples and you have an old HP Printer, they do an automatic $50 instant rebate off a new HP Printer. I'm sure you can get paper off the internet in bulk for cheaper. Hope this helps.

What type of work are you doing?  You said wide format for proofing.  An Officejet is not a proofer and will not deliver a "proof".  Yes, it is a decent large format "Office" jet; but not a proofer.  I am currently in the same situation you are.  I am looking for a designer friendly large format proof printer.  You simply will not get that unless you go the extra step with the RIP.  I've used a 13x19 Postscript printer in the past and they are very well worth the money when you are a designer and a client needs to see an accurate proof.  You simply bill it and, if you have the work, you eventually make your money back.  It's an investment.  HP currently has 6-mo interest free; Epson has a $200.00 rebate until 07/31.  I just have a problem with the cost of consumables.  The cartridges are a big pain.  I hope I can still write them off as business expenses.  Oh, that brings up another point.  The equipment is tax deductable ( at least it was the last I checked ).

You want to look for the Tabloid Plus (12x18) size or a Super B (13x19) size. Stores typically don't carry these sizes. Check online at Graytex Papers www.graytex.com.  I have a Epson 1400 that can use up to the 13x19 and the office has an HP Officejet Pro K8600 that does good color, but has trouble printing borderless on the large 13x19's. Hope this helps.

UV FLATBED PRINTER / UVB SERIES

This series UV printers is specialized in printing sheet to sheet and roll to roll. Sheet media don’t move during printing, the print head carriage moves left and right and the beam moves front and back to finish printing. Print height reach 10cm maximum.

There is a total of 8 pieces of UVB series of different size, such as 2.5m*1.25m, 2.5m*.1.55m, 3m*1.8m, 3.5m*2m.

Adopting print head of Epson DX5 and Seiko, the machines of this series can print the pictures with high efficiency and resolution.