Electrostatographic reproduction machine having dual mode development unit control apparatus and method

摘要

A method and apparatus in an electrostatographic reproduction machine having a plurality of development units for reliably producing high quality toner particle images under varying sustained area toner coverage conditions. The apparatus employing the method includes a control system (a) for reading a stored area toner coverage level threshold value; a first operating time control algorithm and a second operating time control algorithm for adding and admixing in each development unit of the plurality of development units; (b) for measuring sustained area toner coverage levels of images being reproduced during a reproduction job; (c) for comparing the measured sustained area toner coverage levels of images being reproduced with the stored area toner coverage level threshold value; and (d) for changing the operating time control algorithm for adding and admixing in each development unit between the first operating time control algorithm and the second operating time control algorithm depending on a result of comparing the measured sustained area toner coverage levels of images being reproduced with the stored threshold value.