打印机上的 back cover open close the back cover 是什么意思呀

打印机上的 back cover open close the back cover 是什么意思呀 联想打印机,M3120 ,出现close the back cover,back cover open! 打印机型号：兄弟FAX-2820.不能打印 显示close the back cover open ,可是后盖是关好的 复印机故障显示 back cover open close the back cover 出现back cover open close the back cover. 兄弟出现back cover open close the back cover. 我的联想3220一体机提示Back cover open close the back cover.如题 兄弟7010开机滴滴的响、出现Back cover open close the Back cover是怎么回事? Back cover open ciose the Back cover 兄弟7010打印机滴滴响.back cover open the back cover怎么办 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, 英文"OPEN BACK COVER THEN REMOVE PAPER