This Nut, Penholder is suitable for Roland CJ-400 printers. This is the original Roland part (number 22285503).
 
Printer compatibility
Roland BN-20
Roland CJ-400
Roland CJ-500
Roland CJ-540
Roland CJ-60
Roland CJ-70
Roland CM-12
Roland CM-24
Roland CM-300
Roland CM-400
Roland CM-500
Roland CS-20
Roland CX-12
Roland CX-24
Roland CX-300
Roland CX-400
Roland CX-500
Roland DPX-4700LS
Roland EGX-30
Roland GX-300
Roland GX-400
Roland GX-500
Roland PC-50
Roland PC-60
Roland PC-600
Roland PNC-1000a
Roland PNC-1050
Roland PNC-1100
Roland PNC-1200
Roland PNC-1210
Roland PNC-1410
Roland SP-300i
Roland SP-540i
Roland VP-300i
Roland VP-540i
Roland VS-300i
Roland VS-540i
Roland VS-640i
Roland SC-540
Roland SC-545ex
Roland SP-300
Roland SP-300v
Roland SP-540v
Roland VP-300
Roland VP-540
Roland LEC-300
Roland GX-640