Network Printers wont wake up after sleeping or goes to sleep between two jobs

[tlfmd]

I have two LaserJet printers networked. Both can be accessed via WIndows 10 64 bit wired and wirelessly, and iOS wirelessly.

It is typical that a Windows job will connect, print, but the second will not, "printer offline". Yet, the iOS will print.

Sometimes the iOS job will not print. Restarting always fixed and they are both in the same room, and inn the same room with one of the Windows machines.

Print doctor does not help, cannot find printers.

This problem also happened when  connected USB on LaserJet Color Pro 400 dn.

[Repairatrooper]

Make sure the firmware is up to date and check the wake on settings to make sure that USB and network events will wake printers.

[tlfmd]

I have checked, both are up to date

LaserJet Pro 400 color M451dn

Color LAser Jet Pro MFP M277dw

Most annoying, is the LJ Pro 400 is behind a wireless router, thus not actually wireless, yet it will work through wireless from iPad  right after the Windows machine, wired, cannot contact.

[tlfmd]

Interestingly, it works after 30 minute delay another time,  or it quits during a job, sends message that it is offline, went offline during the job,