打印机显示Front or Rear Cover Open PC Print Pending `

打印机显示Front or Rear Cover Open PC Print Pending ` 传真机出现< front or rear> cover open 打印机显示PC-print是什么意思? M7020打印机显示我Open the front Cover and remove the Drum then rem 打印机显示“open the front cover and remove the Drum,then remove j 兄弟一体机DCP-7010,打印机显示“open the front cover and remove the Drum 联想(lenovo M3120)打印机显示：Dust on Drum.Open the front Cover and 兄弟打印机报open rear cover remoye paper pc print pending [jam 1] or No Cartridge 三星SCX-4521F出现Front or Rear,Cover Op m7020联想打印机出现以下提示:cover is open close the front cover请问是什么意思, 打印机显示paper ram check rear dor and then open and close top