Hi I have a Tecnicolor 582n wifi Router. I have several laptops and 2 wifi printers (Canon Pixma 495, HP Deskjet 3630) on my home network. Periodically (i.e. every few days) the router loses connection to the 2 printers, i.e. I cannot "ping" either of their IP addresses from any of the laptops. I have both printers set to always use the same IP addresses in the router settings. Resetting the router fixes the problem and I can print for another few days until the router loses connection again.
Sounds frustrating! I'm not familiar with your equipment, but what occurs to me is
Are the printers connected by 2.4Ghz or 5Ghz wifi? 5Ghz is faster, but it doesn't usually reach as far. If they can connect by 2.4Ghz, try that. Further down this line of thought, if you can, try connecting one or both by a temporary ethernet cable. If they stay on line, consider buying/using powerline-ethernet adaptors to connect them. (I don't think printers need high-throughput connections. I use such things to connect my printer, without issues.)
Maybe the router GUI will show you some logs of connection/disconnections. Anything informative in there? Do they drop off simultaneously? (That would need explaining...) Obviously they're not connected if you can't ping them. If the Technicolor will show you what it believes are connected, does it agree with reality? I might look into how long DHCP leases are on the router. Even static IP's might need renegotiation between the router and printers, that fails for some mad reason.
I presume you've tried power-cycling the printers. They don't reconnect? Again, anything in router logs?
How precisely are the printers connected when they work? My printer's basically available as an "ipp" printer. There are all kinds of ways to configure printers, but I found this simplest to serve a mixture of microsoft and linux machines.
Oh, if it's possible, try setting up an infrequent "ping" from an always-on machine to one/both of the printers -- once a minute should do. Does that help? (Would need explaining...)
Hoping at least to spark some thoughts that might solve your problem.