Canon imageCLASS MF5550 Basic Manual page 111

INCORRECT PAPER SIZE ↔ CASS PAPER MISMATCH
Cause
Remedy
INSTALL CARTRIDGE ↔ TONER SUPPLY LOW
Cause
Remedy
LOAD LTR SIZE PAPER
Cause
Remedy
MEMORY FULL
PRESS SET KEY
Cause
9
Remedy
PRINTER DATA ERROR
Cause
Remedy
9-10 LCD Messages
The size of the paper in the cassette or multi-purpose feeder is different from
that of the paper specified in <PAPER SIZE> in <COMMON SETTINGS> of the
Menu.
Load the correct paper size or change <PAPER SIZE> in <COMMON
SETTINGS> of the Menu. (See "Loading Paper," on p. 2-4, or "Specifying the
Paper Size," on p. 5-3.)
Then reset the machine by opening the front cover and then closing it.
The cartridge is not installed or not installed correctly.
Install the cartridge correctly. (See "Replacing the Cartridge," on p. 8-14.)
No LTR-size paper is loaded in the cassette or multi-purpose feeder.
Load LTR-size paper in the cassette or multi-purpose feeder. (See "Loading
Paper," on p. 2-4.)
The machine's memory is full because the collate copy function was set when a
large document is loaded.
Divide the document and copy each part separately.
If <MEMORY FULL> and <PRESS SET KEY> appear while scanning
documents using the ADF, the document being scanned stops in the ADF. In
this case, press [Set] to make the document come out automatically.
A problem has occurred in the data transmission between the machine and
your computer.
Use System Monitor to delete the current print job.