Minimum replenisher dispense strategy for improved xerographic stability

1 . An electrostatic printing machine having a development station having a toner dispenser for dispensing toner in said development station and wherein the said electrostatic printing machine employs a method for improving xerographic stability of toner in said development station, comprising:

reviewing a print job comprising job images for toner usage;

calculating a dispense rate base on said toner usage, print job attributes, and sensing toner quantity that is present;

comparing the calculated dispense rate to a predefined minimum dispense rate; and

if said calculated dispense rate is less than said predefined minimum dispense rate, setting the toner dispenser to said predefined minimum dispense rate; said setting includes scheduling a detone process if the toner mass in said development station exceeds a predefined threshold value.

2 . The printing machine of claim 1 , further including varying said predefined minimum dispense rate as a function of time.

3 . The printing machine of claim 1 , further including varying said predefined minimum dispense rate as a function of estimated toner age.

4 . The printing machine of claim 1 , wherein said reviewing includes:

performing a pixel count for each color plane on a sheet level of the print job; converting the pixel count to a percent area coverage per color plane; and

in feed-forward mode comparing the area coverage per color plane to a dispense rate lookup table; and

in a feed-back mode comparing the present toner mass to a desired toner mass set point.

5 . The printing machine of claim 1 , wherein said scheduling includes printing a MAC patch with said developer station.

6 . The printing machine of claim 5 , wherein said scheduling further includes measuring the TC in said developer station.

7 . A method for improving xerographic stability of toner in a development station, comprising:

reviewing a print job comprising job images for toner usage;

calculating a dispense rate base on said toner usage, print job attributes, and sensing toner quantity that is present;

comparing the calculated dispense rate to a predefined minimum dispense rate; and

if said calculated dispense rate is less than said predefined minimum dispense rate, setting the toner dispenser to said predefined minimum dispense rate; said setting includes scheduling a detone process if the toner mass in said development station exceeds a predefined threshold value.

8 . The method of claim 7 , further including varying said predefined minimum dispense rate as a function of time.

9 . The method of claim 7 , further including varying said predefined minimum dispense rate as a function of estimated toner age.

10 . The method of claim 1 , wherein said reviewing includes:

performing a pixel count for each color plane on a sheet level of the print job; converting the pixel count to a percent area coverage per color plane; and

in feed-forward mode comparing the area coverage per color plane to a dispense rate lookup table; and

in a feed-back mode comparing the present toner mass to a desired toner mass set point.

11 . The method of claim 1 , wherein said scheduling includes printing a MAC patch with said developer station.

12 . The method of claim 11 , wherein said scheduling further includes measuring the TC in said developer station.