Ginjirō Shirogane was the lieutenant of the 6th Division prior to Renji Abarai. He is the father of Mihane Shirogane. He resigned from his position to run the sunglasses store: Silver Tonbo. He began doing this work on the side while he was a lieutenant, but when he started getting a lot of business, he took it up full time.
Ginjirō is not mentioned in the manga or anime. He is only revealed in the Bootleg databook.