Using a Kofax embedded scanning solution (eCopy ShareScan, AutoStore, Equitrac Office, Equitrac Express, Ricoh PCC, etc.) on specific Ricoh MFP models (MP C300, 305, C305, 306, C306, C306Z, C400, C401, C406, C406Z, 406, C407, 501, C501, IM 350F, 430F, and other "A4" models), and using the "Auto" paper size setting, scanning does not succeed. When using the document feeder, the paper may be fed partway through then stop. Similarly, scanning from the flatbed glass with "Auto" paper size, the scanning does not succeed. An error "The format of the original is unknown" may be displayed.
Those Ricoh MFP models do not support the "Auto" paper size detection. Similarly "Mixed" input size is not supported. These are Ricoh MFP device limitations, as these models do not have a document size sensor.
Use the specific paper size that matches the input paper size - i.e. Letter R, A4R, Legal, etc. If the correct input paper size is selected, scanning succeeds.
AutoStore with Combined Client - see KB: Adding scan settings for Ricoh A4 devices like MP C307
Equitrac with PCC 4 - define the default page size using the Remote Administration Tool
ShareScan 5.x with Embedded Client - see KB: Ricoh A4 Devices fail to pull in paper through the ADF when Auto-detect is selected