Method and apparatus for scanning and printing documents with text and images

DETAILED DESCRIPTION In a majority of high quality printing situations, the text and line art are printed in a different color than the images.
Usually black is used for the text while the three primary subtractive colors of cyan, magenta and yellow are used for images.
The data path of the present invention is for a fixed resolution 500 dpi printer to receive an input at about 250 dpi.
The lower resolution input allows for maintaining full throughput of the system by reducing the period needed for transmitting the print data to the printer.
It also reduces the cost of the printer by reducing the size of the frame-store needed.
When extremely high quality text is needed, the printing system will accommodate it by handling the black separation at full resolution of 500 dpi from beginning to end.
The Image Data Manager(IDM) creates the black text at 500 dpi and sends it to the printer.
The printer will print the 3-color image(s) as they are scanned by the scanner at 250 dpi in normal operating mode and without any skip cycles.
The transmission of the black separation to printer may take 10 to 30 seconds.
Meanwhile, the print engine will skip cycles.
When the printer frame-store is full with the 500 dpi black separation, the exposure begins.
The interpolator is bypassed in this mode and data is directly read from the frame-store into the edge enhancer subsystem.
The printer resolution is always fixed at 500 dpi.
The laser interface section is also designed for 500 dpi printing and its clock rate will remain constant.
It is an object of the present invention to solve the problems encountered in the prior art.
In the present invention, high resolution data is used for text and lower resolution data is associated with images that are to be printed.
This is achieved using a fixed resolution printer without the enormous expense associated with multi-resolution printers.
Also, a simple, single, and straight forward data path is used and only one frame-store is needed in the data path thereby simplifying the system and reducing cost