Color standard and method of calibrating a multi-color electrophotographic printing machine

Claim 3

A method as recited in claim 1, wherein said step of setting the printing machine in the calibration mode includes the steps of: inserting a toner dispenser housing toner particles of a color corresponding to the first color test copy being reproduced into the development system of the printing machine; determining the number of copies required to actuate the developability regulating mechanism to energize the toner dispenser and increase tHe concentration of toner particles within the developer mix; placing the color standard in the printing machine as the original document to be reproduced when the toner dispenser is energized prior to the formation of the predetermined number of test copies; and forming a first color test copy without an original document in the printing machine when the toner dispenser is not energized prior to the formation of the predetermined number of test copies.

Claim 4

A method as recited in claim 2, further including the steps of: printing a plurality of first color test copies when the color standard is disposed in the printing machine until a predetermined number of first color test copies are produced without the toner dispenser being energized by the developability regulating apparatus; and comparing the first color test copy immediately prior to the toner dispenser being energized, and the first color copy immediately following the printing of the predetermined number of first color test copies with the color standard to determine if the first color test copy prior to toner dispensing and the first color test copy subsequent to the printing of the predetermined number of first color test copies are intermediate the maximum and minimum density ranges of the color standard.

Claim 5

A method as recited in claim 1, further including the steps of: setting the printing machine in the color calibration mode of operation for producing a second color test copy; actuating the printing machine to produce a second color test copy; comparing the second color test copy with the color standard; and adjusting the developability regulating mechanism until the density of the second color test copy is intermediate the maximum and minimum density ranges of the color standard.

Claim 6

A method as recited in claim 4, further including the steps of: setting the printing machine in the color calibration mode of operation for producing a third color test copy; actuating the printing machine to produce the third color test copy; comparing the third color test copy with the color standard; and adjusting the developability regulating mechanism until the density of the third color test copy is intermediate the maximum and minimum density range of the color standard.

Claim 7

A method as recited in claim 1, further including the steps of: setting the printing machine in the exposure calibration mode of operation after said step of adjusting the developability regulating mechanism; actuating the printing machine to produce a plurality of first color test copies with the color standard disposed therein as the original document; comparing each first color test copy with the color standard; adjusting the exposure system of the printing machine until each first color test copy reproduced therein is of a predetermined exposure condition; and determining the neutral density filter to be utilized in the exposure system of the printing machine in the normal operating mode thereof.

Claim 8

A method as recited in claim 1, further including the steps of: actuating the printing machine to produce a multi-color test copy; comparing the multi-color test copy with the color standard; and adjusting the electrical bias of each developer unit of the development system in the printing machine until the multi-color test copy is reproduced within the specified density ranges of the color standard.

Claim 9

A color standard for calibrating a multi-color electrophotographic printing machine, including: a generally planar support member; a plurality of color samples disposed on said support member, each of said color samples being of a predetermined hue, value and chroma so as to be substantially optimum for reproduction as a test copy on the printing machine; and a plurality of pairs of limit color samples disposed on said support member, each of said pair of limit color samples corresponding in hue, value and chroma to one color Being reproduced by the printing machine, one of said limit color samples being of a maximum acceptable density and the other of said limit color samples being of a minimum acceptable density to define the permissible density range for each of said colors being reproduced by the multi-color electrophotographic printing machine.

Claim 10

A color standard for calibrating a multi-color electrophotographic printing machine, including: a generally planar support member; a plurality of color samples disposed on said support member, each of said color samples being of a predetermined hue, value and chroma so as to be substantially optimum for reproduction as a test copy on the printing machine; and a plurality of pairs of limit color samples disposed on said support member, each of said pair of limit color samples corresponding in hue, value and chroma to one color Being reproduced by the printing machine, one of said limit color samples being of a maximum acceptable density and the other of said limit color samples being of a minimum acceptable density to define the permissible density range for each of said colors being reproduced by the multi-color electrophotographic printing machine.

Claim 11

A color standard as recited in claim 8, wherein said support member includes a plurality of apertures therein, each of said apertures passing through one of said limit color samples permitting the color copy corresponding thereto to be disposed therebeneath so as to be visible through the aperture for comparison therewith to ascertain whether the color is between the maximum and minimum acceptable density range of said limit color samples.

Claim 12

A color standard as recited in claim 9, wherein said plurality of limit color samples include: a high density cyan color sample and a low density cyan color sample; a high density magenta color sample and a low density magenta color sample; and a high density yellow color sample and a low density yellow color sample.

Claim 13

A color standard as recited in claim 9, wherein said plurality of limit color samples include: a high density red color sample and a low density red color sample; a high density cyan color sample and a low density cyan color sample; and a high density black color sample and a low density black color sample.

Claim 14

A color standard as recited in claim 8 for a multi-color electrophotographic printing machine having a development system with a controllable developer bias voltage arranged to adjust copy image density, wherein said plurality of color samples include an array of developer color samples disposed on said support member, said array of developer color samples comprising a first set of developer bias color samples adapted to be reproduced only when the electrical bias of the development system is less than the optimum value, a second set of developer bias color samples corresponding to the optimum electrical bias of the development system, and a third set of developer bias color samples adapted to indicate when the electrical bias of the development system is greater than the optimum value.

Claim 15

A color standard as recited in claim 12, wherein: said first set of developer bias color samples include a light blue color sample, a light pink color sample, and a light yellow color sample; said second set of developer bias color samples include a substantially pure red color sample, a substantially pure green color sample, and a substantially pure blue color sample; and said third set of developer bias color samples include a contaminated red color sample, a contaminated green color sample, and a contaminated blue color sample.

Claim 16

A color standard as recited in claim 12, wherein: said first set of developer bias color samples include a light red color sample and a light blue color sample; said second set of developer bias color samples include a substantially pure red color sample and a substantially pure blue color sample; and said third set of developer bias color samples include a contaminated red color sample and a contaminated blue color sample.

Claim 17

A color standard as recited in claim 8, wherein said plurality of color samples include a plurality of pairs of exposure color samples disposed on said support member, one of said exposure color samples of each of said pairs of exposure samples being arranged to indicate an underexposed condition for the printing machine, and the other of said exposure color samples of each of said pairs of color samples being arranged to indicate an overexposed condition for the printing machine.

Claim 18

A color standard as recited in claim 15, wherein said pairs of exposure color samples include a first pair of exposure samples having one exposure color sample arranged to indicate an underexposed condition for the development of a cyan image in the printing machine, and the other eXposure color sample arranged to indicate an overexposure condition for the development of the cyan image in the printing machine.

Claim 19

A color standard as recited in claim 16, wherein said pairs of exposure color samples include a second pair of exposure color samples having one exposure color sample arranged to indicate an underexposed condition for the development of a yellow and magenta image in the printing machine, and the other exposure color sample arranged to indicate an overexposed condition for the development of a yellow and magenta image in the printing machine.