Process control for electrophotographic recording

A method for controlling recording parameters in an electrostatographic recording apparatus, the apparatus including an image recording member, a primary charger for establishing a uniform primary voltage level (V.sub.o) on the image recording member, a recorder device for recording an electrostatic image on the image recording member in response to an exposure parameter E.sub.o, a development station for developing the electrostatic image with charged toner particles and having a electrical bias V.sub.B for establishing an electrical field to attract toner to the image recording member, the method comprising the steps of:

• periodically operating the apparatus to record toned patches of different target densities;
• measuring density of the toned patches;
• calculating for each target density a difference value between target density and measured density;
• multiplying the difference value by a respective set of constants associated with a target density to calculate respective adjustments .DELTA.E.sub.o, [.DELTA.V.sub.O ] .DELTA.V.sub.0 and .DELTA.delV to E.sub.o, V.sub.o and del V, respectively, wherein
• delV=V.sub.o -V.sub.B ;
• and in response to said adjustments adjusting E.sub.o, V.sub.o and V.sub.B for recording subsequent images.

A method for controlling electrostatic charge level established on a surface comprising the steps of:

• operating a charger device to establish a level of charge on the surface;
• sensing the level of charge on the surface;
• calculating a difference between the sensed level of charge and a target level of charge;
• adjusting the charger in accordance with the calculated difference and a parameter related to charger efficiency.

A method for controlling recording parameters in an electrostatographic recording apparatus, the apparatus including an image recording member, a primary charger for establishing a uniform primary voltage level (V.sub.o) on the image recording member, a recorder device for recording an electrostatic image on the image recording member in response to an exposure parameter E.sub.o, a development station for developing the electrostatic image with charged toner particles and having a electrical bias V.sub.B for establishing an electrical field to attract toner to the image recording member, the method comprising the steps of:

• periodically operating the apparatus to record toned patches of different target densities;
• measuring the densities of the toned patches;
• calculating for each target density a difference value between target density and measured density;
• multiplying the difference value by a respective set of constants associated with a target density of relatively higher density to calculate respective adjustments .DELTA.E.sub.o, [.DELTA.V.sub.O ] .DELTA.V.sub.0 to E.sub.o, V.sub.o respectively;
• in response to said adjustments adjusting E.sub.o and V.sub.o for recording a first set of subsequent images;
• multiplying the difference value by a constant associated with a target density of relatively lower density to calculate an adjustment .DELTA.delV to delV, wherein delV=V.sub.0 -V.sub.B ;
• and
• in response to the adjustment .DELTA.delV adjusting V.sub.B for recording a second set of subsequent images.