what is best printer for new El Capitan?

That is a very broad question without knowing what your needs and desires are. There are many printers that work fine with El Capitan. If you would give a few details on what you are looking for such as do you print a lot, often, do you need color, multi functions, is price a consideration, etc., then others can give more specific advise to your needs.

Also, did you check the website of your printer to see if they have any upgrades for El Capitan or if they are planing to release drivers for it? Did you consider using generic drivers for your old printer?

For me, I use an HP multi function B&W laser printer. HP seems to keep up to date on compatibility better that a lot of other brands. I gave up on ink jets due to high cost of ink cartridges and cartridges drying up from low use.

For what it's worth, the HP site seems to suggest it is compatible with 10.11.

http://support.hp.com/us-en/product/HP-Officejet-4620-e-All-in-One-Printer/51012 29/model/5101234/document/c04473034

Yes, as stedman1 said, it does seem compatible with El Capitan. But their website is a bit confusing on the OS it works with. Latest update is 12.34 on Dec 6, 2015.

I did notice there is a built in driver in El Capitan for the 4620 series Fax. Maybe that is all you need. At least the Fax should work. I've found that choosing software that is close with another printer works also for many occasions.

I would try downloading the latest software and re add the printer in to see if you can get it to work.

http://support.hp.com/us-en/drivers/selfservice/HP-Officejet-4620-e-All-in-One-P rinter-series/5101229/model/5101234

I have a small graphics biz, I have always used Epson photo inkjets. Veery happy with the output

Glad that worked out for you.

I've had my printer for a long time. Even in times when HP didn't have updated drivers for my model, I managed to use either Gutenprint drivers or another HP printer's driver that was a similar printer to mine and that worked just fine. HP has always been good about keeping up to date with the printer drivers at least to a point that they would work.

You're Welcome & Happy New Year to you also

You are quite welcome.

Did you try this one

I use an HP Officejet Pro 8620 very happy with it.

Never again will i ever buy an Epson—the manual calibration on those is a nightmare.

I have been using a HP 110a ink jet (print fax scan) for several years and when I switched from PC to a late 2015 mac book pro I had no problems what so ever.