Method for setting up an electrophotographic printing machine using a toner area coverage sensor

A method of adjusting image quality in a printing machine having a variable density image developed on a photoconductive surface in accordance with an initial set of starting values, including:

• detecting a plurality of densities of the variable density image and transmitting a plurality of signals with each signal being indicative of a density;
• generating new starting values, responsive to the plurality of signals, using a linearized perturbation model;
• calculating error values, responsive to the plurality of signals, minimizing a sum of squares of the error values;
• testing the error values for convergence to a set of reference values with each reference value indicative of an acceptable density;
• repeating said detecting, transmitting, generating, calculating, and testing, steps for a plurality of iterations;
• branching to a component responsive to the error values exceeding the reference values and the plurality of iterations exceeding a first prescribed value;
• and
• adjusting the component, said adjusting comprises adjusting a voltage for a developer unit having a mixture of toner particles and carrier granules therein, and adjusting a toner dispenser for discharging toner particles into the developer unit, including:
• comparing a developer state variable to a first development parameter;
• generating a toner concentration value, responsive to the developer state variable exceeding the first development parameter;
• comparing the developer state variable to a second development parameter;
• generating a second toner concentration value, responsive to the developer exceeding the second development parameter;
• adjusting the voltage for the developer unit;
• detecting a plurality of densities of the variable density image and transmitting a plurality of signals with each signal being indicative of a density;
• generating new starting values, responsive to the plurality of signals, using a linearized perturbation model;
• calculating error values, responsive to the plurality of signals, minimizing the sum of squares of the error values;
• testing the error values for convergence to a set of reference values with each reference value indicative of an acceptable density;
• repeating said adjusting, detecting, transmitting, generating, calculating, and testing steps for the first mentioned plurality of iterations and a second plurality of iterations;
• and
• branching to a second component, responsive to the error signals exceeding the reference signals, and the first mentioned plurality of iterations exceeding the first mentioned prescribed value and the second plurality of iterations exceeding a second prescribed value.