Hi,
The following would be entirely experimental. It may not work at all.
If it is not possible to find a compatible driver, a discussion Samsung ML-1860 and latest MacOS could possibly be of interest. The workaround (for another model) described by Matti Haveri is intended to eliminate a problem with a downloaded package (containing older drivers) not opening/installing under the latest operating system versions. Something similar could perhaps be worth a try. Under Samsung Printer Drivers v2.6 for OS X, the article Printer and scanner drivers for Mac - Apple Support lists a Samsung SCX-4623 Series version 1.08.01 driver.
Before testing anything, make absolutely sure that you have backup copies of all important files. Software conflicts cannot be ruled out.
You may have to reset the printing system between tests. See this article for details:
Reset the printing system on your Mac to solve a problem – Apple Support (UK)