Feed forward and feedback toner concentration control utilizing post transfer sensing for TC set point adjustment for an imaging system

An electrostatic printing machine having a toner concentration control system for maintaining image quality in a developer structure, the toner concentration control system comprising:

• a transfer efficiency estimator for measuring a transfer efficiency estimates indicative with a developed image on an imaging surface before and after transfer;
• and a toner dispenser, responsive to said transfer efficiency estimator, for adjusting a toner dispense rate based on measured said transfer efficiency estimate compare to a transfer efficiency target value.

A method for maintaining image quality in a developer structure in an electrostatic printing machine having a toner concentration control system, comprising:

• measuring a transfer efficiency estimates indicative with a developed image on an imaging surface before and after transfer;
• and
• adjusting a toner dispense rate of a toner dispenser based on the error signal based upon the measured transfer efficiency estimate compare to a transfer efficiency target value.

A toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner, the toner concentration control system comprising:

• a toner concentration sensor providing estimate of the toner concentration in the developer housing,
• a feedback dispense unit receiving the toner concentration estimate and transmitting a dispense rate adjustment command based on the toner concentration estimate and a pre specified target value, a toner usage estimator, a feed forward dispense unit transmitting a feed forward dispense rate adjustment command based on the toner usage estimate, a transfer efficiency estimator providing a transfer efficiency estimate of a post-transfer image quality value on a photoreceptor;
• and a feedback dispense unit receiving the transfer efficiency estimate and transmitting a toner concentration target adjustment command based on the transfer efficiency estimate.