If you go to windows explorer and paste
%LOCALAPPDATA%\Microsoft\Device Metadata\dmrccache\en-us
into the path bar. Then under some of the GUID folders there you will find a
DeviceInformation subfolder with a .ico file in it. If the .ico is there that you see as your printer then you should be able to replace it. However if there is NO .ico for your device/printer then it should be using the default icons stored in %SystemRoot%\system32\DDORes.DLL and to change it there you would need a resource editor (if you try something like resource hacker on the DLL then always back up the original DLL first).
Another thought: According to Brink on his forum the meta data for devices (including the icon) may download automatically if you enable automatic updates and have it set to treat Recommended updates the same as Critical. Personally I discourage this setting as it also may download drivers that are sometimes not correct so maybe you have it turned off too. If so then maybe you should manually go out to windows updates and download any recommended updates waiting that apply to printers.
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