$backupRootPath = "I:\Share01_Backup"
$fromPath       = "E:\Share01\"
$weekFolder     = (Get-Date).DayOfWeek
$toPath         = ("{0}\{1}"              -f $backupRootPath, $weekFolder)
$logPath        = ("{0}\robocopy_{1}.log" -f $backupRootPath, $weekFolder)

# 曜日フォルダを作る ※7世代のバックアップを作ることになる
New-Item -path $backupRootPath -Name $weekFolder -ItemType Directory -Force
 
# 曜日フォルダにコピーを取る
ROBOCOPY $fromPath $toPath * /PURGE /NP /NDL /FP /BYTES /LOG:$logPath