Electrophotographic color proofing apparatus and method

Apparatus for generating from half-tone patterns, a proof which is formed of dots and is derived from a record member that is adapted to selectively maintain an electrical pattern, the apparatus comprising:

• charging means selectively coupled to the record member for causing a preselected amount of charge to be deposited on the record member, the charging means being operative in response to a first signal;
• forming means for forming an electrical pattern on the record means which is a reproduction of the half-tone patterns, the forming means being operative in response to a second signal;
• the record member being adapted to facilitate generation of a proof which comprises a visual representation comprised of a plurality of dots of the electrical pattern;
• dot size control means for generating and cooperatively varying the first and second signals;
• and
• the proof having an acceptable relationship to a press sheet printed on a printing press which uses printing plates derived from the same half-tone patterns.

Electrophotographic apparatus for generating from a set of halftone patterns formed of dots, a proof which is formed of dots and is derived from a record member that is adapted to selectively maintain an electrical pattern, the apparatus comprising:

• charging means selectively coupled to the record member for causing a preselected amount of charge to be deposited on the record member, the charging means being operative in response to a first signal;
• exposure means for exposing the record member in the presence of the half-tone patterns to a source of radiation which results in the information contained in the half-toned patterns being reproduced on the record member, the exposure means being operative in response to a second signal;
• development means for producing from the pattern containing record member, the proof which comprises a visual representation of the record member, the development means being operative in response to a third signal;
• and
• dot size control means for generating and cooperatively varying the first, second, and third signals so as to control the size of the dots on the proof.

Electrophotographic apparatus for generating from a set of half-tone color separations formed of dots and derived from artwork, a proof which is formed of dots and is derived from a component of an electrophotographic record member that is adapted to maintain an electrical charge, the proof having an acceptable relationship to the artwork and to a press sheet comprised of dots and printed on a printing press which uses printing plates derived from the same separations, the apparatus comprising:

• charging means selectively coupled to the record member for causing a preselected amount of charge to be deposited on the record member, the charging member being operative in response to a first signal;
• exposure means for exposing the record member in the presence of the half-tone separations to radiation which results in the information contained in the half-tone separations being reproduced on the record member, the exposure means being operative in response to a second signal;
• development means for producing from the record member which contains the information of the half-tone separations, the proof which comprises a visual representation of the information contained on the record member, the development means being operative in response to a third signal;
• and
• dot size control means for generating and cooperatively varying the first, second, and third signals so as to control the size of dots on the proof.

Electrophotographic apparatus for generating a proof from a set of half-tone color separations comprising:

• platen means for receiving a photoconductive record member;
• means for receiving on said platen a half-tone color separation which is placed between the platen and a photoconductive record member;
• charging means including a control grid for applying a controlled charge potential on a photoconductive record member;
• means for controlling the exposure of a photoconductive layer of a photoconductive record member through a separation to a suitable source of radiant energy to form a latent electrostatic image of a pattern carried by said separation;
• a plurality of development electrodes for developing said resulting latent electrostatic image with a selected one of a plurality of color toners;
• means for controlling the voltage on said selected development electrode during a toning operation;
• and
• means for controlling the dot size of an image formed on a photoconductive record member by cooperatively varying the exposure, the grid potential on said charger and the potential on said selected development electrode.

An electrophotographic color imaging apparatus for generating a proof from a set of half-tone color separations comprising:

• platen means for receiving a photoconductive record member;
• means for receiving on said platen a half-tone separation which is placed between the platen and said photoconductive record member;
• charging means including a control grid for applying a controlled charge potential on a photoconductive record member;
• means for controlling the exposure of a photoconductive layer of a photoconductive record member through a separation to a suitable source of radiant energy to form a latent electrostatic image of a pattern carried by said separation;
• a plurality of development electrodes for developing said resulting latent electrostatic image of a pattern carried by said separation;
• a plurality of development electrodes for developing said resulting latent electrostatic image with a selected one of a plurality of color toners;
• means for controlling the voltage on said selected development electrode during a toning operation;
• and
• means for controlling the dot size in the image formed on said photoconductive record member by cooperatively varying the grid potential on said charger and the potential on said selected development electrode for a given exposure.

A method for controlling electrophotographic apparatus which generates a proof from a set of half-tone separations, wherein said apparatus provides a reproduction of a press sheet that would be produced using printing plates derived from said separations by controllably toning a pre-defined color onto said proof during each one of a series of successively occurring toning passes, said method comprising the steps of:

• predicting performance using models of various electrophotographic processes that will occur within said apparatus during the present toning pass for a pre-selected one of said colors;
• providing, in response to said performance predictions, a value of at least one control parameter for use in controlling the actual performance of said apparatus during the toning pass;
• toning the pre-selected color onto said proof;
• measuring an actual value of at least one process parameter, indicative of the actual performance of said apparatus, occurring during the present toning pass for said pre-selected color;
• and
• updating, after said pre-selected color has been toned onto said proof, at least one coefficient value appearing in at least one of said models, using the measured process parameter value, for use during the next successive toning pass occurring for said proof or for a corresponding toning pass for a subsequently occuring proof.

A method for use in controlling electrophotographic apparatus which generates a proof from a set of half-tone separations, wherein said apparatus provides a reproduction of a press sheet that would be produced using printing plates derived from said separations by controllably toning a pre-defined color onto said proof during each one of a series of successively occurring toning passes, said method comprising a calibration pass phase followed by at least one toning pass phase,

• wherein the calibration pass phase comprises the steps of:
• obtaining initial measurement of at least one pre-defined characteristic indicative of initial system performance;
• and
• updating at least one coefficient value appearing in at least one model which mathematically describes a corresponding electrophotographic process that occurs in the apparatus;
• and
• wherein said toning pass phase comprises the steps of:
• predicting performance, using said model with said updated coefficient value, of said electrophotographic process that will occur during the present toning pass for a pre-selected one of said colors;
• and
• providing, in response to said performance predictions, a value of at least one control parameter for use in controlling the actual performance of said apparatus during the toning pass;
• toning the pre-selected color onto said proof;
• measuring an actual value of at least one process parameter, indicative of the actual performance of said apparatus, occurring during the present toning pass for said pre-selected color;
• and
• updating, after said pre-selected color has been toned onto said proof, said coefficient value, using the measured process parameter value, for use during the next successive toning pass occurring for said proof or for a corresponding toning pass in a subsequently occurring proof;
• and
• repeating said toning pass phase for each remaining toning pass needed for the present proof.

Electrophotographic apparatus for generating a proof from a set of half-tone separations, wherein said apparatus provides a reproduction of a press sheet that would be produced using printing plates derived from said separations by controllably toning a pre-defined color onto said proof during each one of a series of successively occurring toning passes, said apparatus comprising:

• means for predicting performance using models of various electrophotographic processes that will occur within said apparatus during the present toning pass for a pre-selected one of said colors, and
• means for providing, in response to said performance predictions, a value of at least one control parameter for use in controlling the actual performance of said apparatus during the toning pass;
• means for toning the pre-selected color onto said proof;
• means for measuring an actual value of at least one process parameter, indicative of the actual performance of said apparatus, occurring during the present toning pass for said pre-selected color;
• and
• means for updating, after said pre-selected color has been toned onto said proof, at least one coefficient value appearing in at least one of said models, using the measured process parameter value, for use during the next successive toning pass occurring for said proof or for a corresponding toning pass in a subsequently occurring proof.

Electrophotographic apparatus for generating a proof from a set of half-tone separations, wherein said apparatus provides a reproduction of a press sheet that would be produced using printing plates derived from said separations by controllably toning a pre-defined color onto said proof during each one of a series of successively occurring toning passes, said apparatus and means for performing at least one toning pass,

• wherein the calibration pass performing means comprises:
• means for obtaining initial measurements of at least one pre-defined characteristic indicative of initial system performance;
• and
• means for updating at least one coefficient value appearing in at least one model which mathematically describes a corresponding electrophotographic process that occurs in the apparatus;
• and
• wherein said toning pass performing means comprises:
• means for predicting performance, using said model with said updated coefficient value, of said electrophotographic process that will occur during the present toning pass for a pre-selected one of said colors;
• and
• means for providing, in response to said performance predictions, a value of at least one control parameter for use in controlling the actual performance of said apparatus during the toning pass;
• means for toning the pre-selected color onto said proof;
• means for measuring an actual value of at least one process parameter, indicative of the actual performance of said apparatus, occurring during the present toning pass for said pre-selected color;
• means for updating, after said pre-selected color has been toned onto said proof, said coefficient value, using the actual process parameter value, for use during the next successive toning pass occurring for said proof or for a corresponding toning pass in a subsequently occurring proof;
• and
• means for repeating said toning pass phase for each remaining toning pass needed for the present proof.