Apparatus for controlling toner replenishment in electrostatographic printer

Claim 2

In an electrostatographic machine including (1) means for contacting an electrostatic image-bearing member with a mix of toner and carrier particles for development, and (2) means for replenishing the toner in the mix; the improvement comprising: means for producing a toner depletion signal having a value indicative of the rate of toner usage; means responsive to said depletion signal for actuating toner replenishing proportionally according to the value of said depletion signal; means for producing a second signal having a value proportional to toning contrast; and means, responsive to said second signal value, for adjusting the constant of proportionallity between the rate of toner usage and the depletion signal value.

Claim 3

The improvement as defined in claim 1 wherein; said machine further includes a print head and means to apply character print signals to said print head; and said toner depletion signal is proportional to the number of character print signals applied to the print head.

Claim 4

The improvement as defined in claim 2 wherein said characters are pixels to be toned.

Claim 5

In an electrostatographic machine including (1) means for substantially uniformly charging a recording member, having image areas, to a primary voltage; (2) means for imagewise exposing the charged recording member to produce discrete latent charge images; (3) means, including a biased electrode, for developing the latent charge images, the electrode bias, the exposure level, and the primary voltage being process control parameters; and (4) means for controlling at least one of the process control parameters for a given image area to adjust the maximum output image density D max ; the improvement comprising: means for producing a toner depletion signal; means for proportionally converting the depletion signal to a toner replenishment control signal; means, for the given image area, for comparing the value of said at least one of the controlled process control parameters to a predetermined target value to produce a difference signal; and means for adjusting the constant of proportionallity of the converting means in response to the difference signal.

Claim 6

In an electrostatographic machine including (1) means for substantially uniformly charging a recording member, having image areas, to a primary voltage; (2) means for imagewise exposing the charged recording member to produce discrete latent charge images; (3) means, including a biased electrode, for developing the latent charge images, the electrode bias, the exposure level, and the primary voltage being process control parameters; and (4) means for controlling at least one of the process control parameters for a given image area to adjust the maximum output image density D max ; the improvement comprising: means for producing a toner depletion signal; means for proportionally converting the depletion signal to a toner replenishment control signal; means, for the given image area, for comparing the value of said at least one of the controlled process control parameters to a predetermined target value to produce a difference signal; and means for adjusting the constant of proportionallity of the converting means in response to the difference signal.

Claim 7

The improvement as defined in claim 4 wherein; said machine further includes a print head and means to apply character print signals to said print head; and said toner depletion signal is proportional to the number of character print signals applied to the print head.

Claim 8

The improvement as defined in claim 5 wherein said characters are pixels to be toned.

Claim 9

The improvement as defined in claim 4 wherein said adjusting means is a proportional and integral controller.

Claim 10

In an electrostatographic machine including (1) means for substantially uniformly charging a recording member, having image areas, to a primary voltage, (2) means for imagewise exposing said member to produce discrete latent charge images for development, and (3) means for controlling the primary voltage to adjust the maximum output image density D max ; the improvement comprising: means for producing a toner depletion signal; means for proportionally converting the toner depletion signal to a toner replenishment control signal; means, for the given image area, for comparing the primary voltage value to a predetermined target value to produce a difference signal; and means for adjusting the constant of proportionallity of the converting means in response to the difference signal.

Claim 11

In an electrostatographic machine including (1) means for substantially uniformly charging a recording member, having image areas, to a primary voltage, (2) means for imagewise exposing said member to produce discrete latent charge images for development, and (3) means for controlling the primary voltage to adjust the maximum output image density D max ; the improvement comprising: means for producing a toner depletion signal; means for proportionally converting the toner depletion signal to a toner replenishment control signal; means, for the given image area, for comparing the primary voltage value to a predetermined target value to produce a difference signal; and means for adjusting the constant of proportionallity of the converting means in response to the difference signal.

Claim 12

The improvement as defined in claim 8 wherein; said machine further includes a print head and means to apply character print signals to said print head; and said toner depletion signal is proportional to the number of character print signals applied to the print head.

Claim 13

The improvement as defined in claim 9 wherein said characters are pixels to be toned.

Claim 14

The improvement as defined in claim 8 wherein said adjusting means is a proportional and integral controller.