Copy contrast and density control

• US 4,350,435 A
• Filed: 04/04/1980
• Issued: 09/21/1982
• Est. Priority Date: 04/04/1980
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Fiske, John M., Velzen, Richard
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Moose, Richard M.
• Application Number:
  US06/137,149
• Time in Patent Office: 900 Days
• Field of Search: 355/14 C, 355/14 E, 355/14 CH, 355/14 D, 355/14 R
• US Class Current: 399/138
• CPC Class Codes: G03G 15/50 Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control sequencing control G03G21/14

Abstract

For use with a copier, apparatus is provided for selecting one of a plurality of sets for adjusting the contrast and density of copies. Each set defines a particular Din/Dout response curve. The apparatus includes a stored matrix of such sets with each set having at least three different values relating to: voltage Vo applied onto the photoconductor by the primary charger, copier exposure Eo, and bias voltage V_B applied to a development station electrode. The operator designates a particular set and logic and control means, adjusts Vo, Eo, and V_B in accordance with the designated set values, and causes the copier to have a particular Din/Dout response curve.

Claims

1. Copy solid area, contrast and density adjusting apparatus for use in a copier having a chargeable photoconductor, adjustable charging means for varying the voltage Vo applied onto the photoconductor, an adjustable exposure station for varying the copier exposure Eo, and a development station having at least one electrode and adjustable bias means for applying an adjustable bias voltage V_B to said electrode for establishing a bias voltage between the photoconductor and said development station to affect copy solid area density;

said apparatus comprising;

(a) memory means having stored therein a matrix of sets of representations of interrelated electrical values, with each such set having values which correspond to specific levels of Vo, Eo, and V_B that define a particular solid area copier Din/Dout response curve with a predetermined breakpoint;

(b) means for addressing said matrix to designate a particular set; and

(c) logic and control means responsive to the values of said designated set to adjust said adjustable charging means, said adjustable bias means and said adjustable exposure station to produce copies in accordance with the Din/Dout response curve defined by such designated set values.

2. Copy solid area, contrast and density adjusting apparatus for use in a copier having a chargeable photoconductor, adjustable charging means for varying the voltage Vo, applied onto the photoconductor, an adjustable exposure station for varying the copier exposure Eo, and a development station having at least one electrode and adjustable bias means for applying an adjustable bias voltage V_B to said electrode for establishing a bias voltage between the photoconductor and said development station to affect copy solid area density;

said apparatus comprising;

(a) memory means having stored therein a matrix of sets of representations of interrelated electrical values, with such matrix having a plurality of columns and plurality of rows wherein at the intersection of each column and row there is a set of values which correspond to specific levels of Vo, Eo, and V_B that define a particular solid area copier Din/Dout response curve with a predetermined breakpoint;

(b) means for addressing a particular column and a particular row of such matrix to designate the set located at their intersection; and

(c) logic and control means responsive to the values of said designated set to adjust said exposure station, said charging means, and said adjustable bias means respectively to thereby optimize copy solid area contrast and density.

3. Copy solid area, contrast and density adjusting apparatus for use in a copier having a chargeable photoconductor, adjustable charging means for varying the voltage Vo, applied onto the photoconductor, an adjustable exposure station for varying the copier exposure Eo, and a development station having at least one electrode and adjustable bias means for applying an adjustable bias voltage V_B to said electrode for establishing a bias voltage between the photoconductor and said development station to affect copy solid area density;

said apparatus comprising;

(a) a stored matrix of sets of representations of interrelated electrical values, with such matrix having a plurality of columns and plurality of rows wherein at the intersection of each column and row there is a set having values which correspond to specific levels of Vo, Eo, and V_B that define a particular copier solid area Din/Dout responsive curve having a predetermined breakpoint, and wherein the Din/Dout response curve corresponding to a set in any row position of a particular matrix column is substantially identical in shape but has a different breakpoint;

(b) means for addressing a particular column and a particular row of such matrix to designate the set located at their intersection; and

(c) logic and control means responsive to the values of said designated set to adjust said exposure station, said charging means, and said adjustable bias means respectively to thereby optimize copy solid area contrast and density.

4. The invention as set forth in claim 3 wherein the Din/Dout responsive curve for each row position of a matrix column is substantially identical in shape but has a different breakpoint.

5. A method of controlling the contrast and density of copies produced by a copier having a magnetic brush with a developer roller, comprising the steps of:

(a) storing in a memory of matrix array of sets of representations of interrelated electrical values, with each set having values which respectively corrrespond to specific levels of the voltage Vo applied onto the copier photoconductor, the copier exposure Eo, and the bias V_B applied to the developer roller to establish a voltage between the development roller and the photoconductor respectively;

(b) addressing the matrix to designate a particular set; and

(c) adjusting the voltage Vo, exposure Eo, and the bias voltage V_B in accordance with the values of the designated set to effect a change in the solid area and contrast density of copies.

6. The invention as set forth in claim 5, including the step of choosing a smaller array within the matrix array from which sets can be designated.

7. Copy, line and solid area, contrast and density adjusting apparatus for use in a copier having a chargeable photoconductor, adjustable charging means for varying the voltage Vo applied onto the copier photoconductor, an adjustable exposure station for varying the exposure Eo, and a dual magnetic brush development station with developer and transport rollers, said apparatus comprising:

(a) adjustable bias means for applying an adjustable bias voltage V_B to said developer roller for establishing a voltage between such roller and the photoconductor to affect copy solid area density;

(b) means for applying a predetermined bias voltage to said transport roller for establishing a voltage between such transport roller and the photoconductor to affect line copy density;

(c) memory means having stored therein a matrix of sets of representations of interrelated electrical values, with such matrix having a plurality of columns and plurality of rows wherein at the intersection of each column and row there is a set having values which correspond to specific levels of Vo, Eo, and V_B that define a particular copier Din/Dout response solid area, curve with a predetermined breakpoint;

(d) means for addressing a particular column and a particular row of such matrix to designate the set located at their intersection; and

(e) logic and control means responsive to the values of said designated set to adjust said exposure station, said charging means, and said adjustable bias means respectively to thereby optimize copy solid area contrast and density.

8. A method of controlling the line and solid area, contrast and density of copies produced by a copier having a dual magnetic brush with developer and transport rollers, comprising the steps of:

(a) biasing said transport roller with a predetermined voltage for establishing a voltage between such roller and the photoconductor to affect copy line contrast and density;

(b) biasing said developer roller with an adjustable bias voltage V_B for establishing a voltage between such roller and the photoconductor to affect copy solid area density;

(c) storing in a memory a matrix of sets of representations of interrelated electrical values, with each set having values respectively corresponding to specific levels of the voltage Vo applied onto the copier photoconductor, the copier exposure Eo, and the bias V_B applied to the developer roller to establish a voltage between the development roller and the photoconductor respectively;

(d) addressing the matrix to designate a particular set of values; and

(e) adjusting the voltage Vo, exposure Eo, and the bias voltage V_B in accordance with the values of said designated set to effect a change in the line and solid area, contrast and density of copies.