In an image forming apparatus identifying recording materials to decide
printing conditions, information concerning the type of the recording
materials identified by a recording material identification unit is
stored for each paper feed port. In a subsequent print job to be printed,
the use of the information having been stored in advance makes it
possible to omit the recording material identification process for the
subsequent recording materials. This stored information includes
individual information for each recording material and a determined value
obtained from a plurality of a plurality of pieces of individual
information. Once the determined value is set, the determined value is
used thereafter. These pieces of stored individual information and the
determined value are initialized when a change of paper or the like is
detected at the paper feed port corresponding to the value and to the
information.