Xerox Corporation

Matrix Integrated Systems, Inc.

Prasad P Padmanabhan

Mark A Scheuer

Joseph W Ward

Eric Michael Gross

Eric Scott Hamby

Patricia Joanne Donaldson

Scott J Baron

Daniel W MacDonald

Gerald M Cox

Edward W Smith, Jr

Paul A Garsin

John Buranicz

Albert Wang

Lingappa K Mestha

A system is disclosed for speeding workpiece thoughput in low pressure, high temperature semiconductor processing reactor. The system includes apparatus for loading a workpiece into a chamber at atmospheric pressure, bringing the chamber down to an intermediate pressure, and heating the wafer while under the intermediate pressure. The chamber is then pumped down to the operating pressure. The preferred embodiments involve single wafer plasma ashers, where a wafer is loaded onto lift pins at a position above a wafer chuck, the pressure is rapidly pumped down to about 40 Torr by rapidly opening and closing an isolation valve, and the wafer is simultaneously lowered to the heated chuck. Alternatively, the wafer can be pre-processed to remove an implanted photoresist crust at a first temperature and the chamber then backfilled to about 40 Torr for further heating to close to the chuck temperature. At 40 Torr, the heat transfer from the chuck to the wafer is relatively fast, but still slow enough to avoid thermal shock. In the interim, the pump line is further pumped down to operating pressure (about 1 Torr) behind the isolation valve. The chamber pressure is then again reduced by opening the isolation valve, and the wafer is processed.

Apparatus for increased workpiece throughput

A method is disclosed for speeding workpiece thoughput in low pressure, high temperature semiconductor processing reactor. The method includes loading a workpiece into a chamber at atmospheric pressure, bringing the chamber down to an intermediate pressure, and heating the wafer while under the intermediate pressure. The chamber is then pumped down to the operating pressure. The preferred embodiments involve single wafer plasma ashers, where a wafer is loaded onto lift pins at a position above a wafer chuck, the pressure is rapidly pumped down to about 40 Torr by rapidly opening and closing an isolation valve, and the wafer is simultaneously lowered to the heated chuck. Alternatively, the wafer can be pre-processed to remove an implanted photoresist crust at a first temperature and the chamber then backfilled to about 40 Torr for further heating to close to the chuck temperature. At 40 Torr, the heat transfer from the chuck to the wafer is relatively fast, but still slow enough to avoid thermal shock. In the interim, the pump line is further pumped down to operating pressure (about 1 Torr) behind the isolation valve. The chamber pressure is then again reduced by opening the isolation valve, and the wafer is processed.

Method for increased workpiece throughput

Method and apparatus for increased workpiece throughput

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. The toner concentration control system maintains toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system includes a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted by toner age, toner break-in and temperature in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

Toner concentration control for an imaging system

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More specifically, the present invention relates to a feed forward toner concentration control system and method for replacing toner in each developer structure, which was used to develop a latent image on a photoreceptor belt, in order to maintain toner concentration in at least one developer structure. First and second pixel counts for first and second toner in each sector are received. The first toner mass is estimated based on first pixel counts. The second toner mass is estimated based on second pixel counts. Feed forward dispense commands are generated based on first toner mass estimate and second toner mass estimate to dispense each toner into each corresponding developer structure to replace toner used to develop the latent image on the photoreceptor in order to maintain toner concentration in each developer structure.

Feed forward toner concentration control for an imaging system

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More, specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system including: a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted for toner age in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

Feed forward and feedback toner concentration control for an imaging

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system includes a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted for toner break-in in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

An electrostatographic printing machine having an imaging member with a surface voltage potential and a control system including first and second reference values. A sensor measures first and second surface voltage potentials that are compared to the first and second reference values to provide first and second error signals to control first and second process stations in the printing machine. A first compensator responds to the first error signal to provide a first weighted adjustment to the first process station and a second weighted adjustment to the second process station. A second compensator responds to the second error signal to provide a first weighted adjustment to the second process station and a second weighted adjustment to the first process station in order to compensate for coupling effects between adjustments to either the first or second processing stations.

Electrostatic control with compensation for coupling effects

In process control loops by keeping the DMA (Developed Mass per unit Area) under control, the print quality can be satisfactorily maintained to within tolerance in spite of temporal variabilities in subsystem parameters. The DMA is measured by creating patches in the interdocument zones. Three patches are created, one at high area coverage (90% to 100%), one at low area coverage (0 to 20%) and one at mid tone (around 50%). These DMA readings are compared to the setpoints. The errors are processed in the controller to generate the internal process parameters known as the cleaning voltage, discharge ratio and development voltage. These internal parameters have well known meaning to the physical xerographic process. The cleaning voltage is used to indicate the background in printing. The discharge ratio gives an indication of how much dot growth is present in the halftones. Finally, the development voltage is proportional to how much toner is laid on the photoreceptor. A controller is shown with these three process parameters, so that when used appropriately, good quality color prints can be obtained.

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San Francisco, CA, United States of America

Prasad P Padmanabhan