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US 5,471,313 AGranted
Method and control system architecture for controlling tone reproduction in a printing device
AssigneeXerox Corporation
InventorsTracy E. Thieret, Thomas A. Henderson, Michael A. Butler
Life of this patent
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Abstract
A controls system architecture for an image output terminal (IOT) has a hierarchical structure which isolates subsystem controls for purposes of efficient algorithm design, analysis and implementation. The architecture is preferably divided into three levels and has a controls supervisor which provides subsystem isolation functions and reliability assurance functions. The architecture improves image quality of IOT outputs by controlling the operation of the IOT to ensure that a toner reproduction curve of an output image matches a tone reproduction curve of an input image, despite several uncontrollable variables which change the tone reproduction curve of the output image.
Claims35
A control assembly for controlling tone reproduction in a system having a plurality of printing subsystems, the printing subsystems cooperating to form and output image on a substrate, the control assembly comprising:
- means for inputting image data representative of an input image;
- a first plurality of control means, each of the first plurality of control means controlling a corresponding one of the plurality of printing subsystems, each of said first plurality of control means comprising:
- sensing means for sensing and outputting subsystem performance data of the corresponding printing subsystem, and
- controller means for generating and outputting a subsystem performance control signal to the corresponding printing subsystem based on a current subsystem performance parameter and the sensed subsystem performance data output by the corresponding sensing means, the corresponding printing subsystem controlled to minimize a difference between the sensed subsystem performance data and the current subsystem performance parameter;
- a second plurality of control means, each of the second plurality of control means controlling and adjusting an intermediate process output, each of said second plurality of control means comprising:
- sensing means for sensing intermediate process output data,
- generating means for generating at least one recommended subsystem performance parameter for at least one corresponding control means of the first plurality of control means based on the intermediate process output data and at least one intermediate system performance setpoint, and
- output means for outputting at least one of said at least one recommended subsystem performance parameters;
- and
- a controls supervisor communicating with said first plurality of control means and said second plurality of control means and inputting the at least one recommended subsystem performance parameter output from said second plurality of control means, said controls supervisor comprising:
- revising means for revising at least one subsystem performance parameter based on the at least one recommended subsystem performance parameter output by the second plurality of control means and at least one current subsystem performance parameter of the first plurality of control means, and
- output means for outputting the at least one revised subsystem performance parameter determined by said revising means to corresponding ones of said first plurality of control means.
9 more elements
An image output terminal having a marking engine and an intrinsic tone reproduction curve, the image output terminal comprising:
- a plurality of subsystems which cooperate to produce a desired output image;
- and
- a control assembly for controlling the plurality of subsystems, the control assembly comprising:
- means for inputting image data representing an input image:
- a first plurality of control means, each of the first plurality of control means controlling a corresponding one of the plurality of subsystems, and comprising,
- sensing means for sensing subsystem performance data of the corresponding printing subsystem, and
- controller means for generating and outputting a subsystem performance control signal based on a current subsystem performance parameter and the sensed subsystem performance data output by the sensing means so that the subsystem performance data corresponds to the subsystem performance parameter;
- a second plurality of control means, each of the second plurality of control means controlling and adjusting an intermediate process output, and comprising,
- sensing means for sensing intermediate process output data,
- generating means for generating at least one recommended subsystem performance parameter for at least one corresponding control means of the first plurality of control means based on the intermediate process output data and an intermediate system performance setpoint, and
- output means for outputting at least one of said at least one recommended subsystem performance parameters based on the intermediate process output data and the intermediate system performance setpoint;
- and
- a controls supervisor communicating with said first plurality of control means and said second plurality of control means and inputting at least one recommended subsystem performance parameter output from said second plurality of control means, said controls supervisor comprising,
- revising means for revising at least one subsystem performance parameter based on the at least one recommended subsystem performance parameter output from the second plurality of control means to adjust the intermediate process output data to conform with the intermediate system performance setpoint, and
- output means for outputting the at least one revised subsystem performance parameter to at least one of said first plurality of control means;
- wherein said sensing means in the second plurality of control means generate system performance setpoints on the intrinsic tone reproduction curve and said controls supervisor outputs the at least one revised subsystem performance parameters to ensure that a tone reproduction curve of the image output matches a tone reproduction curve of the input image.
13 more elements
A method for controlling a printing system having a plurality of subsystems, a plurality of subsystem controllers and an image developing controller, comprising the steps of:
- inputting data representative of an image;
- generating system performance setpoints from the input image data;
- generating subsystem performance parameters based on said system performance setpoints, each subsystem performance parameter corresponding to one of the plurality of subsystems;
- controlling a performance of each of the plurality of subsystems by sensing subsystem performance data and adjusting subsystem performance based on the sensed performance data and the corresponding subsystem performance parameter;
- sensing system setpoint performance;
- and
- adjusting the subsystem performance parameters during printing operation to produce a desired output image.
4 more elements
Dependencies are inferred from the claim text.