This printer has a history of suddenly deciding that the Multipurpose tray (the one that pulls down from the front of the printer) is to be used as a manual feed tray. After printing a job, the printer will set and flash its light until you press the Go button. It will then pull from the front tray no matter where you told it to print from. I've see it do this even when the config page (printed by pressing both the Go and Job Cancel buttons at the same time while the printer is ready) clearly shows that MANUAL FEED is OFF. The solution is to cold reset the printer to factory defaults.
To cold reset the printer to the factory defaults turn it off, and then hold down the "Job Cancel" key (the small one) for 10 seconds while turning the printer back on.
To reset the printer to the preset defaults turn it off, and then hold down the "Go" key (the Big one) for 10 seconds while turning the printer back on.
See also:
@PJL ECHO PUP_START @PJL INFO ID "HP LaserJet 2100 Series" @PJL INFO STATUS CODE=10023 DISPLAY="PROCESSING JOB" ONLINE=TRUE @PJL INFO CONFIG IN TRAYS [2 ENUMERATED] INTRAY1 MP INTRAY2 PC OUT TRAYS [1 ENUMERATED] NORMAL FACEDOWN PAPERS [16 ENUMERATED] LETTER LEGAL A4 EXECUTIVE COM10 MONARCH C5 DL ISOB5 B5 CUSTOM JISB5 JPOST JPOSTD A5 FOOLSCAP LANGUAGES [2 ENUMERATED] PCL PCLXL USTATUS [4 ENUMERATED] DEVICE JOB PAGE TIMED MEMORY=4194304 @PJL INFO PAGECOUNT 535 @PJL INFO VARIABLES LANG=ENGLISH [15 ENUMERATED] ENGLISH FRENCH GERMAN ITALIAN SPANISH SWEDISH DANISH NORWEGIAN DUTCH FINNISH PORTUGUESE TURKISH POLISH CZECH HUNGARIAN COPIES=1 [2 RANGE] 1 999 PAPER=LETTER [16 ENUMERATED] LETTER LEGAL A4 EXECUTIVE COM10 MONARCH C5 DL ISOB5 B5 CUSTOM JISB5 JPOST JPOSTD A5 FOOLSCAP ORIENTATION=PORTRAIT [2 ENUMERATED] PORTRAIT LANDSCAPE FORMLINES=60 [2 RANGE] 5 128 MANUALFEED=OFF [2 ENUMERATED] OFF ON RET=ON [2 ENUMERATED] OFF ON PAGEPROTECT=AUTO [2 ENUMERATED] AUTO ON RESOLUTION=1200 [3 ENUMERATED] 300 600 1200 PERSONALITY=AUTO [2 ENUMERATED] AUTO PCL TIMEOUT=15 [2 RANGE] 5 300 MPTRAY=FIRST [2 ENUMERATED] CASSETTE FIRST INTRAY1=UNLOCKED [2 ENUMERATED] UNLOCKED LOCKED INTRAY2=UNLOCKED [2 ENUMERATED] UNLOCKED LOCKED AUTOCONT=OFF [2 ENUMERATED] OFF ON DENSITY=3 [2 RANGE] 1 5 PASSWORD=DISABLED [2 RANGE] 0 65535 ECONOMODE=OFF [2 ENUMERATED] OFF ON IOBUFFER=AUTO [3 ENUMERATED] AUTO ON OFF IOSIZE=10 [2 RANGE] 10 10 RESOURCESAVE=AUTO [1 ENUMERATED] AUTO COURIER=REGULAR [2 ENUMERATED] REGULAR DARK WIDEA4=NO [2 ENUMERATED] NO YES REPRINT=AUTO [3 ENUMERATED] OFF ON AUTO TRAY1TEMP=MEDIUM [3 ENUMERATED] HIGH MEDIUM LOW TRAY2TEMP=MEDIUM [3 ENUMERATED] HIGH MEDIUM LOW TESTPAGE="?" [4 ENUMERATED] SELFTEST PCLTYPELIST CONTSELFTEST DEMOPAGE OUTLINEPOINTSIZE=72 [2 RANGE] 12 999 PAGEMFQBEGIN=2750 [2 RANGE] 0 10000 PAGEMFQEND=10000 [2 RANGE] 0 10000 JOBMFQBEGIN=4100 [2 RANGE] 0 10000 JOBMFQEND=10000 [2 RANGE] 0 10000 LPARM:PCL FONTSOURCE=I [2 ENUMERATED] I S LPARM:PCL FONTNUMBER=0 [2 RANGE] 0 54 LPARM:PCL PITCH=10.00 [2 RANGE] 0.44 99.99 LPARM:PCL PTSIZE=12.00 [2 RANGE] 4.00 999.75 LPARM:PCL SYMSET=PC8 [29 ENUMERATED] PC8 ROMAN8 ISOL1 ISOL2 ISOL5 ISOL6 PC775 PC8DN PC850 PC852 PC8TK PC1004 WINL1 WINL2 WINL5 WINBALT DESKTOP PSTEXT LEGAL ISO4 ISO6 ISO11 ISO15 ISO17 ISO21 ISO60 ISO69 WIN30 MCTEXT LPARM:PCL LINETERMINATION=0 [4 ENUMERATED] 0 1 2 3 @PJL ECHO PUP_END