This Ricoh SP C751 JPN RPCS Printer was only released on the Japanese market, and given that it is recommend checking the Ricoh Japan website for the latest driver, direct links are below for all modern versions of Windows 32/64bit.
RPCS driver
File: 231291.exe
RPCS driver
File: 231292.exe
PPD installer for RICOH
File: Ricoh_PS_Printers_Vol4_DOM_LIO_4.2.0.0.dmg