Adaptive process controller for electrophotographic printing

Claim 3

An apparatus according to claim 1 wherein one of the processing stations comprises a developer unit having a mixture of toner particles and carrier granules therein, and a dispenser for discharging toner particles into the developer unit, further including: a detector for measuring toner particle concentration in the developer unit and transmitting a concentration signal indicative thereof, said controller transmitting a reference concentration signal; and a concentration controller, responsive to the reference concentration signal from said controller and the concentration signal from said detector, for transmitting a concentration control signal to the dispenser to regulate discharging of toner particles into the developer unit.

Claim 4

An apparatus according to claim 2, wherein said updater, responsive to the signal from said concentration controller, transmits a concentration correction signal to said controller to correct the reference concentration signal from said controller.

Claim 5

An apparatus according to claim 3, wherein said controller includes: means, responsive to reference signals and the signals from said first mentioned sensor, for generating error signals; and means, responsive to the error signals and the correction signals, for generating the control signals and the reference concentration signal.

Claim 6

An apparatus according to claim 4, wherein said concentration controller includes a proportional integral controller.

Claim 7

An apparatus according to claim 5, wherein said updater includes means for calculating the correction signals by using a linearized perturbation model.

Claim 8

An apparatus according to claim 6, wherein said control signal generating means includes means for calculating the error signals by minimizing the sum of the squares of the error signals.

Claim 9

An apparatus according to claim 1, wherein one of the processing stations comprises a developer unit having an electrical bias applied thereon, said controller transmitting as the control signal a signal to adjust the electrical bias being applied on said developer unit.

Claim 10

An apparatus according to claim 1, wherein one of the processing stations comprises an exposure station adapted to illuminate the surface with light rays of a selected intensity, said controller transmitting as the control signal a signal to adjust the exposure station to control the intensity of the light rays.

Claim 11

An apparatus according to claim 1, wherein one of the processing stations comprises a charging station adapted to charge the surface, said controller transmitting as the control signal a signal to adjust said charging station to control the charge on the surface.

Claim 12

An apparatus according to claim 1, wherein the variable density image developed on the surface includes a solid area density region, a half-tone density region and a highlight density region,

Claim 13

An electrophotographic printing machine of the type having processing stations and a photoconductive member with a solid area density region, a half-tone density region and a highlight density region developed thereon, wherein the improvement includes: a sensor for detecting densities of the solid area density region, half-tone density region and highlight density region developed on the photoconductive member and transmitting a solid area density signal, a half-tone density signal and a highlight density signal indicative of the solid area density region, half-tone density region and highlight density region; an updater, in communication with said sensor, for generating a solid area density correction signal, a half-tone density correction signal and a highlight density correction signal in response to the solid area density signal, half-tone density signal and highlight density signal transmitted thereto from said sensor; and a controller, responsive to the solid area density signal, halftone density signal and highlight density signal from said sensor and the solid area density correction signal, half-tone density correction signal and highlight density correction signal from said updater, for transmitting control signals to the processing stations to regulate the processing stations.

Claim 14

An electrophotographic printing machine of the type having processing stations and a photoconductive member with a solid area density region, a half-tone density region and a highlight density region developed thereon, wherein the improvement includes: a sensor for detecting densities of the solid area density region, half-tone density region and highlight density region developed on the photoconductive member and transmitting a solid area density signal, a half-tone density signal and a highlight density signal indicative of the solid area density region, half-tone density region and highlight density region; an updater, in communication with said sensor, for generating a solid area density correction signal, a half-tone density correction signal and a highlight density correction signal in response to the solid area density signal, half-tone density signal and highlight density signal transmitted thereto from said sensor; and a controller, responsive to the solid area density signal, halftone density signal and highlight density signal from said sensor and the solid area density correction signal, half-tone density correction signal and highlight density correction signal from said updater, for transmitting control signals to the processing stations to regulate the processing stations.

Claim 15

A printing machine according to claim 12 wherein one of the processing stations comprises a developer unit having a mixture of toner particles and carrier granules therein, and a dispenser for discharging toner particles into the developer unit, further including: a detector for measuring toner particle concentration in the developer unit and transmitting a concentration signal indicative thereof, said controller transmitting a reference concentration signal; and a concentration controller, responsive to the reference concentration signal from said controller and the concentration signal from said detector, for transmitting a concentration control signal to the dispenser to regulate discharging of toner particles in the developer unit.

Claim 16

A printing machine according to claim 13, wherein said updater, responsive to the signal from said concentration controller, transmits a concentration correction signal to said controller to correct the reference concentration signal from said controller.

Claim 17

A printing machine according to claim 14, wherein said controller includes: means, responsive to a solid area density reference signal, a half-tone density reference signal and a highlight density reference signal and the solid area density signal, half-tone density signal and highlight density signal from said first mentioned sensor, for generating a solid area density error signal, a half-tone density error signal and a highlight density error signal; and means, responsive to the solid area density error signal, half-tone density error signal and highlight density error signal and the solid area density correction signal, half-tone density correction signal, highlight density correction signal, and concentration correction signal, for generating the control signals and the reference concentration signal.

Claim 18

A printing machine according to claim 15, wherein said concentration controller includes a proportional integral controller.

Claim 19

A printing machine according to claim 16, wherein said updater includes means for calculating the solid area density correction signal, half-tone density correction signal, highlight density area correction signal, and concentration correction signal by using a linearized perturbation model.

Claim 20

A printing machines according to claim 17, wherein said control signal generating means includes means for calculating the solid area density error signal, half-tone density error signal and highlight density error signal by minimizing the sum of the squares of the solid area density error signal, half-tone density error signal and highlight density error signal.

Claim 21

A printing machine according to claim 12, wherein one of the processing stations comprises a developer unit having an electrical bias applied thereon, said controller transmitting as the control signal a signal to adjust the electrical bias being applied on said developer unit.

Claim 22

A printing machine according to claim 12, wherein one of the processing stations comprises an exposure station adapted to illuminate the photoconductive member with light rays of a selected intensity, said controller transmitting as the control signal a signal to adjust the exposure station to control the intensity of the light rays.

Claim 23

A printing machine according to claim 12, wherein one of the processing stations comprises a charging station adapted to charge the photoconductive member, said controller transmitting as the control signal a signal to adjust said charging station to control the charge on the photoconductive member.

Claim 26

A method according to claim 22 wherein one of the processing stations comprises a developer unit having a mixture of toner particles and carrier granules therein, and a dispenser for discharging toner particles into the developer unit, further including the steps of: measuring toner particle concentration in the developer unit and transmitting a concentration signal indicative thereof; and transmitting, in response to a reference concentration signal and the concentration signal, a concentration control signal to the dispenser to regulate discharging of toner particles into the developer unit.

Claim 27

A method according to claim 23, wherein said step of transmitting control signals includes the step of transmitting a concentration correction signal to said controller to correct the reference concentration signal.

Claim 28

A method according to claim 24, said step of transmitting control signals includes the steps of: generating, responsive to reference signals and the density signals, error signals; and generating, responsive to the error signals and the correction signals, the control signals and the reference concentration signal.

Claim 29

A method according to claim 25, wherein said step of generating correction signals includes the step of calculating the correction signals by using a linearized perturbation model.

Claim 30

A method according to claim 26, wherein said step of transmitting control signals includes the step of calculating the error signals by minimizing the sum of the squares of the error signals.

Claim 31

A method according to claim 22, wherein one of the processing stations comprises a developer unit having an electrical bias applied thereon, said step of transmitting control signals including the step of transmitting a signal to adjust the electrical bias being applied on the developer unit.

Claim 32

A method according to claim 22, wherein one of the processing stations comprises an exposure station adapted to illuminate the photoconductive surface with light rays of a selected intensity, said step of transmitting control signals including the step of transmitting a signal to adjust the exposure station to control the intensity of the light rays.

Claim 33

A method according to claim 22, wherein one of the processing stations comprises a charging station adapted to charge the surface, and wherein said step of transmitting control signals includes the step of transmitting a signal to adjust the charging station to control the charge on the photoconductive surface.

Claim 34

A method according to claim 22, further including a step of forming on the photoconductive surface the variable density image with a solid area density region, a half-tone density region and a highlight density region.