Jacob records, "These [small] plates are called the plates of Jacob, and they were made by the hand of Nephi" (Jacob 3:14). In other words, Jacob gives us the idea that the "plates of Nephi" might have taken on the name of the recordkeeper. The idea that Jacob might have been stressing was that from his time forward, the record on the small plates of Nephi would be kept by his lineage and not the lineage of Nephi. Thus, Jacob might have called his record the "plates of Jacob" to distinguish it from the "plates of Nephi" which were kept by the Nephite kings (Omni 1:11). This is bolstered by another statement from Mormon in the Words of Mormon in which he says, referring to the small plates:
"For after I had made an abridgment from the (large) plates of Nephi, down to the reign of this king Benjamin, of whom Amaleki spake, I searched among the records which had been delivered into my hands, and I found these (small) plates, which contained this small account of the prophets, from Jacob down to the reign of this king Benjamin, and also many of the words of Nephi." (Words of Mormon 1:3)
[Alan C. Miner, "The Order of Translation of the Plates of Mormon and Moroni," p. 4]