Patent ID: 7869722

Claim:
A toner dam maintenance system for maintaining a toner dam at a cleaner blade in an electrophotographic machine that cleans a photoconductive surface for receiving toner images thereon, wherein the toner images on the photoconductive surface pass across the cleaner blade, the cleaner blade cleaning toner from the surface thereof while leaving a toner dam on an upstream side of the cleaner blade, the system comprising: a controller including a toner level estimating section that models a toner dam balance of the cleaner blade over time based on received toner input sources including untransferred toner from the print jobs, cycle-in/cycle-out bands of the electrophotographic machine, and untransferred background minus estimated toner leakage from the cleaner blade; and a toner level correction section that provides at least one corrective action to the electrophotographic machine to replenish the toner dam towards a target level range when the toner dam balance is below a threshold level, wherein the corrective action includes inserting a corrective maintenance pattern on the photoconductive surface without transfer of the toner, and wherein modeling values include the following: when cycled in: M R =M R(0) +aT PR −bN PIX at cycle out: M R(0) =M R at cycle in: M R =M R(0) −M CI/CO when a maintenance image is inserted: M R =M R +cN PIX(M1) , where: M R is the maintenance level (in mg) and constrained not to be negative, M R(0) is the maintenance level at cycle out (mg), M CI/CO is the mass of toner developed within the cycle out and in bands (mg), T PR is the time since cycle in (seconds), N PIX is the cumulative pixel count since cycle in (units of 10 5 pixels), N PIX(M)L is the number of pixels in a low area coverage maintenance image (units of 10 5 pixels), N PIX(M)H is the number of pixels in a high area coverage maintenance image (units of 10 5 pixels), N PIX(M1) is the number of pixels in the maintenance image (units of 10 5 pixels) and is one of N PIX(M)L or N PIX(M)H , a is a coefficient (mg per second), b is a coefficient (mg per 10 5 pixels), and c is a coefficient (mg per 10 5 pixels).