Method and system for minimizing non-uniformities in output images using halftone correction patches

A printing apparatus for processing documents containing image data comprising:

• a photoreceptor comprising one or more image areas and an inter-document zone for movement in a process direction, the inter-document zone comprising at least one area on the photoreceptor between the one or more image areas used for output;
• a plurality of color marking stations for applying color in a process direction to the photoreceptor in the one or more image areas and the inter-document zone;
• one or more array sensors for sensing the color applied to the photoreceptor in a cross-process direction;
• a processor for receiving color image data of a document, the image data comprising a plurality of color pixels and the document comprising at least one page of image data, the processor performing the following operations:
• generating a halftone test patch for each color in the image data to be provided in the inter-document zone;
• determining profile data of each test patch, the profile data including an first orientation of halftone dots of the test patch representing a halftone orientation of its associated color for output in the one or more image areas;
• determining a second orientation for the halftone dots of the at least one test patch;
• and
• providing the halftone dots of the at least one test patch at a second orientation in the inter-document zone,
• wherein the halftone orientation of its associated color in the one or more image areas is unaffected for output.