I recently bought an Epson wireless capable printer. I had to run a setup program on my Mac which allowed it to connect to my wireless router without me having to enter any of the router details or password. At no time did I plug in a network cable to the printer, and it is working fine. I can also print from my Win7 laptop any where in the house.
I was curious and checked my dlink router, it does have 1 USB on the back
Printer just arrived - I’m glad I was home when the UPS guy arrived as it’s in a HUGE box (3+ feet on a side), and he set it inside the front door for me. We’ll have to dance around it for a couple of days til I get a chance to set it up.
Former employee of a laser printer manufacturer here (from the mid 1980’s, when it was still rather novel to have a laser printer at all, let alone one that hung directly off an ethernet, let alone even have an ethernet, but still . . .)
Let’s clarify just what a “printer” is these days. Oncet upon a time, a “printer” was a mostly mechanical mochine that took electrical signals and rather simply and directly translated those into mechanical movements that caused type bars to smash into paper through a ribbon.
Modern “printers” of course have a complete microprocessor computer system right within them – or as complete as it needs to be to do whatever your fancy-schmancy printer can do. EVERYTHING these days has a microprocessor, from your wristwatch, to your microwave oven, to your car, to your cell phone . . .
These computers are programmable. And they are more powerful than Bill Gates ever imagined back in 1980. And they have lots and lots of memory. And they can even have their own hard disk drives. (Our printers did.) And they can have their own network interface cards. All this sounds sooooooo old-hat now-a-days, but it was all really cutting edge and so kewl back in 1984. All this leading to my point . . . (wait for it ! . . . )
A modern “printer” can perfectly well be its OWN print server! It can hang directly off an ethernet connection, NOT have to be connected to some port on a separate printer-server machine. It can have its very own local IP address. It has its own user interface, so you can telnet into it and log in to configure it. (You already know that you can connect to your router with your browser, right?) It can manage and spool print jobs coming from all over the local net, and print them in its own well-controlled sequence. It can emulate any number of other printers, from one print job to the next. It can handle things like printing multiple copies of a job, collating them, reversing the order of the pages (depending on whether the pages come out of the printer face-up or face-down), and stuff like that, all by itself.
Give all that, who would doubt that a modern printer could just as well connect to a wireless network as to a wired network? It’s a full computer station in its own right, just as much as any other workstation. All it would need is a wireless NIC, and if has that, it’s wireless! I’d be surprised if such a printer WASN’T available these days.
I just want to mention a couple of things that might be useful to people depending on their circumstances.
If you can’t get a good signal from your router and there’s no place on the printer for an external antenna, you can likely get around the problem using an ethernet bridge or a powerline module.
There are different protocols and most new network accessories (802.11n wireless) are compatible with older standards (like 802.11g), but in that case, it will be cheaper to buy the older type of accessory.
You run an ethernet cable from the printer to the bridge and then position the bridge for the best reception. Data is then relayed in both directions.
For a power line module - actually they come in pairs - plug one in near the router (try not to use a surge protector or UPS - power strip is ok) and connect with a cable. Plug the other module in near the router. Again connect with cable. Transmissions are encrypted so any signal that leaks out to the mains is secure.
Lastly, and a bit off topic, set the security on your router to use WPA2. WEP can be cracked fairly easily. WPA is better but I think has minor vulnerabilities (not sure). WPA2 is the best. With both, hacks are virtually always the result of using a weak password. A long passphrase, like a song lyric (something obscure), that is 20 or 30 characters long but easy to remember should work fine. If you can remember capitalizations and punctuation, so much the better. I use a short sequence of numbers and then do a simple transformation, like adding primes, fibonacci sequence, etc. to get a long but easy to remember number. Doing it that way is more a matter of geek pride than necessity though. 
The one thing no one in this thread has managed to explain is how the printer could connect to a password protected router unless there were some way of entering the password into the printer. Then someone visits me with their own device (laptop, i-pad,…) I have to tell them the password and then they can hook up, no problem. But without it?
We just set up a Cannon MG8200 printer. No wire connection was needed, but we did have to input the router info.
My Canon printer is also a fax so it has a numeric keypad and I punched in the password like texting. Bigger office machines have touchscreen keyboards.