To obtain an image processor for use in an image processing network system in which each resource constituting its hardware is used efficiently.

A controller controls operation of the image processor entirely through a hierarchic software arrangement of an interface driver layer 50, a system OS layer 51 and an application layer 54. A system utility layer 52 and an API layer 53 are provided between the system OS layer 51 and the application layer 54. The API layer 53 has an application program interface (API) 69 supporting delivery of data among the system utility layer 52, the interface driver layer 50, and the application layer 54 wherein the system utility layer 52 has a manager being used commonly from a plurality of applications by its API 69.