Device for high speed two beam printing with parallel processing of image data including density conversion and enhancement

An image processing system for processing input image data for processing two lines of said input image data at the same time, comprising:

• a data bus controller for controlling a parallel data width of said input image data;
• a temporary storage device for temporarily storing said input image data;
• a data storage controller configured to control writing and reading of said input image data into and out of, respectively, said temporary storage device, said data storage controller controlling reading of two lines of said input image data representing input bilevel image data at the same time, and reading of two lines of said input image data representing input multilevel image data at the same time;
• a parallel to serial data converter for converting each of said lines of said input image data from parallel data to serial data, said data converting means varying a transfer rate of each of said lines of said input image data;
• a device configured to transform the two lines of serial data representing said input bilevel image data to multilevel image data;
• a data selector configured to select between the two lines of serial data transformed to multilevel image data and the two lines of serial data representing said input multilevel data;
• and
• a register controller configured to execute register control with at least data stored in a first data storage area included in said device configured to transform,
• wherein said converting each of said lines of said input image data, and in the case of said input bilevel image data, and said transforming the two lines of serial data representing the input bilevel image data to multilevel image data, are effected before either of said two lines of serial data are output from said data selector.