Dear Shlomil,
Thank you for the link to the User Manual for the HP 4635. It does contain much useful information. But, it does not answer a problem following a reset of the date/time. I did reset the date/time as you instructed. Next day it was in error again. I reset it. Next day it was again in error. It appears that the printer shuts down completely by itself when now in use and in doing so upsets the setting of date/time.
I could not find any fix to this in the manual. Can you assist in solving this problem?
Sincerely,
Slim2