1. A translated document image production device, comprising: an extraction section of the device that extracts a group of pixels constituting only a foreground of a character or a character string to be processed from pixels constituting a background of the character or character string; a translation section of the device that translates the character or character string into a translated character or character string; and a region backfill section of the device that backfills only the extracted group of pixels with pixel values representing the background of the character or character string and that writes the translated character or character string over the background.