I have some thousands of 4x6 postcards printed 4:0 on heavy 16pt stock and uv coated on the front. '

The back has not been uv coated but it's still coated stock so inkjet ink seems to not set well at all on it - smears even an hour after printed.

I would like to find a not-too-expensive laser printer that could print these on the back a couple hundred at a time with variable data including not only the address but also a message with a few small light-coverage graphics that have reasonable quality (but immensely high quality is not needed.)

Anyone know of a printer that can feed 16pt 350gsm 4"x6" postcards like this?

I currently have the Ricoh C411dn. I know I can run 14pt on it(through the bypass tray), but too sure about 16pt.
It's got excellent color output and runs like a workhorse.
It ranges about $1,000-$1,300.
Good Luck!

My very cheap, small black and white Ricoh AP2100 will run 12pt fast and with ease but won't pull 16pt cards though. Gave it a little test and it will in fact print 16pt but because of the feed angle which requires the paper to take a z course through the printer (in, 90 degrees up, and 90 degrees out vs. straight through) the 16pt is stiff enough that it needs a firm manual nudge to make it past the first bend. Otherwise it jams right off every time on the stiffer 16pt.

My other really cheap HP2600 will also do 12pt cards, maybe 14pt postcards (not sure) with ease. But the 16pt cards feed inconsistently and they're so heavy it throws the registration off which can't be good.

I follow the stock guidlines percisely on my larger machines so I won't even think of trying that though I believe they would likely handle it, it would cost too much in the long run if it threw a part out of order.

So I suspect the adivce above will be as good as you will get. I don't know of a laser under $1,000 that can do this with ease. The Xante illumina would of course be on target for this job if you could get a well-used one or have other uses for it.