請問如果jam 過紙後, 部份垂直出現矇矓是甚麼問題?

What type of printer do you use?
Laser printer? or Ink jet? What brand?
If Laser printer the problem is the drum/imaging unit/, you will need to replace it

If Inkjet then may be the 墨頭 is dislocated slightly when you pull the paper out. Try to push or pull or tap the mounting of 墨頭 slightly to see if condition improve. There is no drum in ink jet. Also you can check if other things have loose up along where the 墨頭 print. ( 矇矓及鬼影重疊 sounds like out of focus la)

If still have warrantee better take it back to see if it can freely repair.
IF cheap printer better buy a new one if .

可能還有紙碎在內,
要看一看右邊是甩粉, 還是只是矇

若甩粉, 大有機會個heat sink element (drum) 介爛了
若只是矇,但又無甩粉, 打開內裡看一看, 尋找紙碎

若這機年資久或印刷量多的話, 膠滾軸會磨損, 令到很容易 jam紙

現在仍有保養的話, 可打去代理維修
若沒有的話, 可往 shamshuipo 新高登, 有間舖專整 laser printer

可能你部打印機，印得太多野到致打印機不能印得出清淅正常的畫面，
我見意你立刻打電話去供應商講反你現時的情況，
他可能會幫到你但有可會收附加費用。