Q5669-60713 Rollfeed Cutter Assembly for DesignJet T & Z Series Plotter 
Cutter assembly Q5669-60713 is the Automatic cutter for roll feed paper use. 

Used to automatically cutoff the paper at the end of a print job. 
When the cutter blade becomes dull and worn your cutoff ends will begin to look ragged or torn, then it is time for a new one.
 
In DesignJet T610 / T1100 / T1120 this part is usually the cause of the 31:XX 31:02 system error codes.
In DesignJet Z2100 / Z3100 / 3200 Error Code 31:01
In DesignJet Z5200 Error Code 31:YZ

Used on all of these HP DesignJet Plotter and Wide Format Printer Models:
DesignJet T610 24 PRINTER
DesignJet T610 44 PRINTER
DesignJet T620 24IN PRINTER 
DesignJet T1100 24 PRINTER
DesignJet T1100 44 PRINTER
DesignJet T1100PS 24 PRINTER
DesignJet T1100PS 44 PRINTER
DesignJet T1120 SD44-PRINTER
DesignJet Z2100 24 IN PHOTO PRINTER
DesignJet Z2100 24 -n GP Photo Printer/Advanced
DesignJet Z2100 24-in Photo Printer
DesignJet Z2100 24-in Printer
DesignJet Z2100 44 IN PHOTO PRINTER
DesignJet Z2100 44-in Photo Printer
DesignJet Z2100 44-in Printer
DesignJet Z3100 24 IN PHOTO PRINTER
DesignJet Z3100 24-in Photo Printer
DesignJet Z3100 24-inch GP Photo Printer
DesignJet Z3100 44 IN PHOTO PRINTER
DesignJet Z3100PS GP 24 PHOTO PRINTER
DesignJet Z3100PS GP 44 PHOTO PRINTER
DesignJet Z3200 24-IN PHOTO PRINTER
DesignJet Z3200 24-in Photo Printer
DesignJet Z3200 44-IN PHOTO PRINTER
DesignJet Z3200 44-in Photo Printer
DesignJet Z3200PS 24-IN PHOTO PRINTER
DesignJet Z3200ps 24-in Photo Printer
DesignJet Z3200PS 44-IN PHOTO PRINTER
DesignJet Z3200ps 44-in Photo Printer
DesignJet Z5200