1. An image forming apparatus capable of generating image data of print data containing a drawing object to be reused within a job, the image forming apparatus comprising: a cache unit configured to generate data based on the drawing object to be reused and cache the generated data based on the drawing object; an object parallel processing unit configured to divide each page of the print data per drawing object unit and to subject a divided page to raster image processor (RIP) processing in parallel; a page parallel processing unit configured to subject the print data to the RIP processing in parallel per page unit; and a processing control unit configured to control such that, in the print data, the object parallel processing unit executes processing sequentially from an initial page of the print data until the data based on the drawing data having a value equal to or more than a threshold value is cached and the page parallel processing unit executes the processing after the data based on the drawing data having the value equal to or more than the threshold value is cached.