@Kevin_Z 

My Archer is HW 5.0 FW 1.2.4 build 20190403 so is up to date.

Unfortunately this printer dont have wire connection thru ethernet, only WiFi and USB. It doesn't metter if PC is connected via 5GHz or 2.4GHz or cable to the router (printer don't support 5GHz so no choice in this point).

Printer was working fine under old TP-Link WDR4300 (but router started to hang-up few times a week and needed to be restarted too often), after switching router to Archer C9 I'm loosing comunication with printer each time my printer goes off. So when I want to prnt anything I need to switch printer on and then reboot router - then it's all working for some time (until printer goes sleep or switched off). After switching printer on without restarting a router my printer see wifi network (I can also define once again connection from printer panel with SSID and Password and print connection status) but it looks like (or behave like) port used by Epson printing is shuted down by router so PC don't see printer in network. Ping is working with 2-3 ms response time (or about 60-65 ms first attempt when printer is in sleep mode).

@Kevin_Z 

Printer IP 192.168.1.124 Gateway 192.168.1.254 - this is correct - same gateway in all devices and ofcourse this is my router IP. Ping looks like on picture below:

There is no option for me to connect printer to the router via USB port those devices are not in same places and even temporary connection requaried more than15m cable (to hide a cable it wuold be like 40-45m). I don't have problems with printer itself, the problem is that to print something i need to reboot router otherway laptops do not see printer port. I have this printer for some time now, it was working correctly with previous router (same adress same gateway same network SSID, same ARP binding list), I still have old router and printer still works with it without any issue, but with Archer C9 there is something wrong when printer is switched on after router.

@Kevin_Z 

Sorrry for posting one post after another... didnt found post edit function. And I have some new informations about my problems.

First Ping screen with actual status from Archer:

Printer sees network, router sees printer, I've got acces to my local network (and internet of course) but as You can see "Host unreachable" when trying to ping printer. The funny thing is, that at this moment I was able to print from device with IP ...150, but with ping on that device also returned "Host Unreachable".

It seems that problem is solved. For unknown reason router was blocking comunication between local network members on some ports (that's why only printer was makeing trouble). The solution is to select check boxes in guest network settings to permit access to localnetwork and communication between guests. I've switched also guest network on temporary, to check if it will help (wanted to switch printer to guest network but...). As soon as I activated this, my printer started the jobs from queue (without changing wifi settings in it). For me it's little bit strange (I shuld say that this is extraordinarily stupid) that settings for guest network have infuence for "main" networks. Miserable support from tp-link and unlogical behevior of this router makes, that the next router for sure won't be a tp-link one. 

First of all look if there are some available updates. If it won't work, check drivers if they are working properly.

@LucasMay 

About drivers, they are up to date, there is no firmware update for router (there was at least 3 updates from Epson printer since I bought it). And i'm now shure that the problem is in the router firmware... Switching printer to use guest network with activated option for enable guests to acces local network helped only a little bit (now i don't need to restart whole router - it's enough to switch off and back on guest network - still annoying but at least other members don't have connection losts). I needed to print something today - my laptop didn't found printer on Epson port - so no surprise - loged in router again checked the connection between printer and router (ping from router system tools) and there is connection (also no surprise, cause I see connection icon on the printer). I've decided to play little bit with system settings and - Here is first surprise - switching ON AP isolation caused that printer started to print (WHY?). Just for test I took the other PC and - no surprise - no comunication on Epson port... Login once again to router switched OFF AP Isolation and... Second surprise - printer started the job in queue WHY? As described in help AP Isolation should prevent communication between local members - I can imagine there is some translation issuees (using Polish UI) and the meaning of checkbox is opposite, but when there is no difference between switching on and off option which should prevent communication between wifi members and just some other option change causes that I can suddenly acces printer for some time (but only from first device which requested access to printer). About printer firmware update - I've checked if the problem will apear with other router (my old also TP link WDR4300) and it's working like it should.