Electrophotographic recording process control method and apparatus

A method of controlling an electrophotographic reproduction process by adjusting a primary charge parameter V0 and a global exposure parameter E0, comprising:

• charging the surface of an electrostatic recording member in an electrophotographic recording apparatus to a standard primary charge V0s;
• modulating the standard primary charge on the recording member using a first test exposure E1 to form a first exposed test area, and using a second test exposure E2 to form a second exposed test area;
• measuring a first test surface potential V1 in the first exposed test area and a second test surface potential V2 in the second exposed test area;
• calculating an intrinsic sensitivity bm associated with the recording member using V1 and V2;
• calculating an intrinsic toe dm associated with the recording member using V1 and V2;
• calculating a corrective charge parameter V0i using dm;
• calculating a corrective exposure parameter E0i using bm and dm;
• adjusting V0 to equal V0i;
• and
• adjusting E0 to equal E0i.

A method of determining a linear equation for approximating a measured intrinsic sensitivity, bm, of a photoconductor charged to a primary charge, V0, in an electrophotographic recording apparatus, comprising:

• selecting a first exposure E1, and a second exposure, E2;
• generating a plurality of random sensitometric pairs, wherein each of the random sensitometric pairs includes a random intrinsic sensitivity, brand, and a random intrinsic toe, drand;
• calculating a plurality of surface potential pairs using the plurality of random sensitometric pairs, wherein each of the surface potential pairs includes a first photoconductor surface potential, V1, calculated using the first exposure, E1, and a second photoconductor surface potential, V2, calculated using the second exposure, E2;
• and
• successively approximating a set of constants, bm0, bm1, and bm2, by using the plurality of surface potential pairs in the linear equation bm=bm0+bm1*V1+bm2*V2, to calculate a plurality of measured intrinsic sensitivities, bm, and by and selecting bm0, bm1, and bm2 to minimize a variance between the plurality of measured intrinsic sensitivities, bm, and the plurality of random intrinsic sensitivities.

A method of determining a linear equation for approximating a measured intrinsic toe, dm, of a photoconductor charged to a primary charge, V0, in an electrophotographic recording apparatus, comprising:

• selecting a first exposure E1, and a second exposure, E2;
• determining a plurality of random sensitometric pairs, wherein each of the random sensitometric pairs includes a random intrinsic sensitivity, brand, and a random intrinsic toe, drand;
• calculating a plurality of surface potential pairs using the plurality of random sensitometric pairs, wherein each of the surface potential pairs includes a first photoconductor surface potential, V1, calculated using the first exposure, E1, and a second photoconductor surface potential, V2, calculated using the second exposure, E2;
• and
• successively approximating a set of constants, dm0, dm1, and dm2, by using the plurality of surface potential pairs in the linear equation dm=dm0+dm1*V1+dm2*V2, to calculate a plurality of measured intrinsic toes, dm, and selecting dm0, dm1, and dm2 to minimize a variance between the plurality of measured intrinsic toes, dm, and the plurality of random intrinsic toes.

A method of determining a linear equation for approximating a corrective charge parameter, V0i, for use in an electrophotographic reproduction apparatus, comprising:

• generating a plurality of random intrinsic toes, drand;
• calculating a plurality of corrective charge parameter values, V0t, using the plurality of random intrinsic toes;
• and
• using linear regression, the plurality of corrective charge parameter values, and the plurality of random intrinsic toes to calculate the constants V0iM and V0iB in the linear equation
• V0t=V0tM*drand+V0iB.

A method of determining a linear equation for approximating a corrective exposure parameter, E0i, for use in an electrophotographic reproduction apparatus, comprising:

• generating a plurality of random sensitometric pairs, wherein each random sensitometric pair includes a random intrinsic sensitivity, brand, and a random intrinsic toe, drand;
• calculating a plurality of corrective exposure parameter values, E0i, using the plurality of random sensitometric pairs;
• and
• using linear regression, the plurality of corrective charge parameter values, and the plurality of random intrinsic toes to calculate the constants V0iM and V0iB in the linear equation
• E0i=(E0tM*drand+E0iB)/brand.

A method of determining an intrinsic operating sensitivity, b, of a photoconductor relative to a primary charge, V0, applied to a photoconductor before exposure in an electrophotographic recording apparatus, comprising:

• identifying a reference primary charge, V0r;
• identifying p, wherein p is a power dependence of the intrinsic sensitivity on the primary charge;
• and
• calculating the operating intrinsic sensitivity using the reference primary charge, the power dependence of the intrinsic sensitivity on the primary charge, and the equation
• b=br*(V0/V0r)−p.

A method of determining an intrinsic operating toe, d, of a photoconductor relative to a primary charge, V0, applied to a photoconductor before exposure in an electrophotographic recording apparatus, comprising:

• identifying a reference primary charge, V0r;
• identifying m, wherein m is a linear dependence of the intrinsic toe on the primary charge;
• and
• calculating the operating intrinsic toe using the reference primary charge, the linear dependence of the intrinsic toe on the primary charge, and the equation
• d=dr−m*(V0−V0r).