Toner concentration control
A method adjusting variations in toner concentration in a printing machine by first determining a pixel count of documents to be imaged. The system then provides two test targets (114,116) on the imaging surface (12) one of the test targets (114) having a relatively low reflectance and the other test target (116) having a medium reflectance. The reflectance value of the test targets is sensed and the difference between the reflectance values is calculated and compared to a reference value to provide an error value. The system then uses the error value and the pixel count of documents to be imaged to determine a time period of dispense for a toner dispenser. <IMAGE>