Print engine controller for an inkjet printhead

Abstract

A print engine controller for an inkjet printhead includes a data bus. A memory interface is connected to the data bus to provide read and write access to a memory. An external client interface is connected to the data bus to allow external clients to write to a memory via the memory interface. A page expansion unit is connected to the data bus to read compressed page data and to write uncompressed page data to the memory. A line loader and formatter unit is connected to the data bus to read expanded page image data from the memory and to format the expanded page image data for a micro-electromechanical printhead. A printhead interface is connected to the line loader and formatter unit for sending dot data to the printhead.

1 . A print engine controller for an inkjet printhead, the print engine controller comprising
 a data bus;   a memory interface connected to the data bus to provide read and write access to a memory;   an external client interface connected to the data bus to allow external clients to write to a memory via the memory interface;   a page expansion unit connected to the data bus to read compressed page data and to write uncompressed page data to the memory;   a line loader and formatter unit connected to the data bus to read expanded page image data from the memory and to format the expanded page image data for a micro-electromechanical printhead; and   a printhead interface connected to the line loader and formatter unit for sending dot data to the printhead.   
     
     
         2 . A print engine controller as claimed in  claim 1 , which includes a controller unit connected to the data bus to allow external clients to read and write registers and to write data to the memory. 
     
     
         3 . A print engine controller as claimed in  claim 1 , which includes a memory controller connected to the memory interface to provide the memory interface with access to the memory. 
     
     
         4 . A print engine controller as claimed in  claim 1 , in which the external client interface is a high speed interface for connection to a microcontroller, the printhead interface being connectable to the microcontroller to provide print and paper status signals to the microcontroller. 
     
     
         5 . A print engine controller as claimed in  claim 1 , in which the page expansion unit includes a contone decoder unit for expanding a compressed contone layer and for writing decompressed contone data to the memory and a contone reader unit for reading expanded contone image data from the memory. 
     
     
         6 . A print engine controller as claimed in  claim 5 , in which the page expansion unit includes a halftoner compositor unit for dithering the contone layer and compositing bi-level data. 
     
     
         7 . A print engine controller as claimed in  claim 1 , in which the page expansion unit includes a dotline writer for writing channels of dot data for a given print line to the memory.