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:

• http://www.hp.com/cposupport/printers/support_doc/bpl06421.html
• http://www.hp.com/cposupport/printers/support_doc/bpl01965.html#P58_3471 HP LaserJet Printers - Common PJL Commands for Front Panel Settings and Default Page Formatting (nice for printers like the 2100 that have no front pannel)
• http://www.hp.com/cgi-bin/cposupport/get_doc.pl?SNI=hplaserjet8887&LC=printers&Tfile=bpl06594 HP LaserJet 2100 Series Printers - Features in the HP LaserJet Device Configuration and HP LaserJet Utility

@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