Abstract: A printing system for producing prints from a job represented by a stream of image data written in a page description language and having a token expressed as a plurality of bits. The stream of image data is generated by and transmitted from an image data source. The printing system comprises an input section, communicating with the image data source, for receiving the stream of image data. The input section includes an arrangement for reading a block of image data to determine the presence of the token in the block of image data. An area, communicating with the input section, is adapted to store the stream of image data. An arrangement, responsive to the reading means determining the presence of the token, is adapted to initiate a selected operation in the printing system after the input section receives a potion of the stream of image data. A parser, communicating with the storage area, is adapted to parse the stream of image data to separate the stream into a plurality of image-related components.