Adjusting copy contrast and density

• US 4,310,237 A
• Filed: 04/25/1980
• Issued: 01/12/1982
• Est. Priority Date: 04/25/1980
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Gengelbach, Robert D.
• Primary Examiner(s): Moses, R. L.
• Application Number:
  US06/143,189
• Time in Patent Office: 627 Days
• Field of Search: 355/14 E, 355/14 CH, 355/14 C, 355/14 R, 355/67-71, 355/77
• 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

In a copier having stored in memory, a matrix of sets, with each set having at least two different values corresponding to: (i) a specific voltage level Vo applied onto a photoconductor by the primary charger; and (ii) a specific copier exposure level Eo; for a "manufacturing standard" copier, that cause any copier which is identical to such standard copier to have a desired Din/Dout response curve, apparatus is provided which in response to variations from the manufacturing standard copier computes correction values and adjusts the values from the matrix of sets. The apparatus includes logic and control which responds to the adjusted set values to cause the copier to produce copies in accordance with the desired Din/Dout response curve.

Claims

1. In copy solid area, contrast and density adjusting apparatus for use in a copier that uses a chargeable photoconductor to produce copies of originals, said apparatus having adjustable charging means for varying the voltage level V_o applied onto the photoconductor;

and adjustable exposure station for varying the level of the copier exposure E_o, a stored matrix of sets with each set having at least two different values which correspond respectively, to specific levels of V_o and E_o, for a design standard, that cause a copier that meets such design standard to produce copies having solid area contrast and density in accordance with a desired Din/Dout response curve wherein Din refers to original document reflective density and Dout refers to copy reflective density; and

means for designating a particular set;

the improvement comprising;

(a) means for correcting the designated set values of E_o and V_o in accordance with variations in a copier from the design standard; and

(b) logic and control means responsive to said corrected designated set values for adjusting said exposure station and said charging means to thereby cause the copier to produce copies in accordance with the desired Din/Dout response curve which corresponds to the designated set values.

2. A method of controlling the contrast and density of copies of originals produced by a copier designed to a standard and which uses a chargeable photoconductor, comprising the steps of:

(a) storing in a memory, a matrix array of sets, with each such set having values which correspond to the voltage level V_o applied onto the chargeable photoconductor, and the copier exposure level E_o which values would cause a copier meeting such design standard to have a desired Din/Dout response curve wherein Din refers to original document reflective density and Dout refers to copy reflective density;

(b) designating a particular set of such matrix;

(c) adjusting the values of such designated set to compensate for variations in a copier from the design standard; and

(d) adjusting the levels of voltage V_o and exposure E_o, in accordance with the adjusted set values to cause the copier to produce copies having contrast and density in accordance with the desired Din/Dout response curve which corresponds to the designated set values.

3. The invention as set forth in claim 2 wherein said adjusting step includes computing offset and multiplier quantities.