All of the relevant printers on your LAN should be very simply discoverable (visible) within the print dialogue on any ChromeOS device (e.g. Chromebox/book) as follows:
Once you have chosen the Print.. option from the Chrome browser main menu (3 dots), click on the Change.. button on the Destination panel then click on the relevant printer entry listed in Local Destinations. Note that if the last used printer was selected from Local Destinations and you forget to switch the printer on (and allow it time to settle down) before starting the Print dialogue, the default destination will revert to "Save as PDF".
The following example illustrates the (print dialogue) visibility of every printer configured on a small Linux print server running the GitHub Cloud Print connector.
relevant here means either:
(a) All of the printers configured on the server which has been setup in accordance with the GitHub Cloud Print Connector project.
or:
(b) If you have installed the HP Print for Chrome app this will include any app-discoverable HP printers. I suspect that Ricoh Print for Chrome works in a similar way.
should be here means:
If you have installed the HP Print for Chrome app, most HP printer models are naturally discoverable but a few aren't. Such HP printers can be made visible by opening the HP Print for Chrome app configuration module (this is red outlined in the Launcher example shown below)
then choosing the Add Printer option then entering the printer information manually. The Ricoh Print for Chrome app configuration module has similarly (but not identically) designed dialogue.