I don't think the TM showing the time has anything to do with you erasing a backup. It merely shows the last time you backed up. You didn't reset the TM data files. I wouldn't worry about that.
If the TCapsule has been erased and you are ready to backup to it, then open TM preferences and select the disk to back up to and start a backup.
In addition: To clarify a point:
TM backs up every hour unless you manually turn it on and off. If the hour elapses since your last backup and you didn't reselect the backup disk and set your options in TM preferences, you will get an error that it can find your backup disk since you erased it.
Resetting everything as I said will point it the the new backup disk destination. It will do a full backup and take some time. After that, the next backup will be incremental and only take a few minutes.