As far as I can see, the second download (labeled "HP Color LaserJet CP3505 Printer Firmware (Includes Code Signing) for - All Operating Systems - (Must Read README Before Installing)" is named ljCP3505_fw_03_140_1.zip.
I downloaded it, and within the .zip file is the .rfu you're looking for:
$ unzip -l ljCP3505_fw_03_140_1.zip Archive: ljCP3505_fw_03_140_1.zip Length Date Time Name --------- ---------- ----- ---- 24649055 2013-02-20 15:25 ljCP3505fw_03.140.1.rfu --------- ------- 24649055 1 file
Some versions of WinZip and similar tools can extract the "outer" compression layer of self-extracting installer .exes, too. Perhaps you accidentally unpacked the first file instead of the second one? (The default settings of Windows makes it easy to make this mistake, by hiding the filename extensions.)
