# US 2006/0153580 A1 · Tone reproduction curve and developed mass per unit area control method and system

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- Number: US 2006/0153580 A1
- Document ID: US20060153580A1
- Status: Published application
- Kind: A1
- Application number: 11/032,716
- Filed: 2005-01-11
- Published: 2006-07-13
- Earliest claimed: 2005-01-11
- Assignees: Xerox Corporation
- Inventors: Song-Feng Mo; Wendy Apton; Stephen Randall; Jennifer Wagner; David Craig
- Web page: https://patentgrep.com/patent/US20060153580A1

## CPC

- G03G 15/5041: {Detecting a toner image, e.g. density, toner coverage, using a test patch (G03G15/553 takes precedence)}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A method of controlling the solid developed mass per unit area and the tone reproduction curve in a printing machine by reading data from a sensor, comparing the data to an acceptable range of data values, where the data is not within the acceptable range of data values, updating a plurality of control actuators, determining whether the discharge ratio is within an acceptable range of discharge ratio values, where the discharge ratio is within the acceptable range of discharge ratio values, applying new control actuators to a power supply in the printing machine, and where the discharge ratio is not within the acceptable range of discharge ratio values, adjusting raster output scanner exposure per an exposure formula.

## Claims

### Claim 1

A method of controlling the developed mass per unit area (DMA): and the tone reproduction curve (TRC) for a printing machine, the method comprising:
reading data from a sensor;
comparing the data to an acceptable range of data values;
updating a plurality of control actuators, where the data is not within the acceptable range of data values;
determining whether the discharge ratio is within an acceptable range of discharge ratio values;
applying new control actuators to a power supply in the printing machine, where the discharge ratio is within the acceptable range of discharge ratio values; and
adjusting raster output scanner exposure per an exposure formula, where the discharge ratio is not within the acceptable range of discharge ratio values.

### Claim 2 (depends on 1)

The method defined in claim 1, wherein the sensor is a black toner area concentration (BTAC) sensor.

### Claim 3 (depends on 1)

The method defined in claim 1, wherein the data from the sensor includes the relative reflectance of three half-tone patches on a test patch, the half-tone patches comprising 12.5%, 50%, and 87.5%.

### Claim 4 (depends on 1)

The method defined in claim 1, wherein the plurality of control actuators includes VC, EXPOSURE, Vmag and VDAC.

### Claim 5 (depends on 1)

The method defined in claim 1, further comprising updating the control actuators by determining the directionality that the data are out of the range and adjusting a plurality of power supplies in the printing machine via a controller board.

### Claim 6 (depends on 1)

The method defined in claim 1, wherein the discharge ratio is defined as: DR=(|Ve|−|Vr|)/(|Vc|−|Vr|).

### Claim 7 (depends on 6)

The method defined in claim 6, wherein:
Ve is the voltage image reading from the ESV after raster output scanner exposure;
Vr is the residual voltage on the photoreceptor at highest exposure and lowest charge level; and
VC is the charge voltage reading from the ESV when the raster output scanner is off.

### Claim 8 (depends on 1)

The method defined in claim 1, wherein the exposure formula is:
Exposure
=
1
S
⁡
[
(
(

Vc

-

Vr

)
2
-

Vt

2
(

Vc

-

Vr

)
)
-
(
(

Ve

-

Vr

)
2
-

Vt

2
(

Ve

-

Vr

)
)
]

### Claim 9 (depends on 8)

The method defined in claim 8, wherein:
the sensitivity coefficient S is defined as: S=S0*(1−e−k*|Vc|);
the transition point Vt is defined as: Vt=Vt0*|Vc|; and
the voltage image reading Ve is defined as: Ve=|Vr|+DR*(|Vc|−|Vr)|.

### Claim 10 (depends on 1)

The method defined in claim 1, wherein the printing machine comprises a xerographic printing machine.

### Claim 11

A developed mass per unit area (DMA) and tone reproduction curve (TRC) control system for a printing machine, the system comprising:
an electrostatic voltmeter;
an infrared densitometer; and
software means operative on the printing machine to:
read data from a sensor;
compare the data to an acceptable range of data values;
update a plurality of control actuators, where the data is not within the acceptable range of data values;
determine whether the discharge ratio is within an acceptable range of discharge ratio values;
apply new control actuators to a power supply in the printing machine, where the discharge ratio is within the acceptable range of discharge ratio values; and
adjust raster output scanner exposure per an exposure formula, where the discharge ratio is not within the acceptable range of discharge ratio values.

### Claim 12 (depends on 11)

The system defined in claim 11, wherein the sensor is a black toner area concentration (BTAC) sensor.

### Claim 13 (depends on 11)

The system defined in claim 11, wherein the data from the sensor includes the relative reflectance of three half-tone patches on a test patch, the half-tone patches comprising 12.5%, 50%, and 87.5%.

### Claim 14 (depends on 11)

The system defined in claim 11, wherein the plurality of control actuators includes VC, EXPOSURE, Vmag and VDAC.

### Claim 15 (depends on 11)

The system defined in claim 11, wherein the software means is also operative on the printing machine to update the control actuators by determining the directionality that the data are out of range and adjust a plurality of power supplies in the printing machine via a controller board.

### Claim 16 (depends on 11)

The system defined in claim 11, wherein the discharge ratio is defined as: DR=(|Ve|−|Vr|)/(|Vc|−|Vr|).

### Claim 17 (depends on 16)

The system defined in claim 16, wherein:
Ve is the voltage image reading from the ESV after raster output scanner exposure;
Vr is the residual voltage on the photoreceptor at highest exposure and lowest charge level; and
VC is the charge voltage reading from the ESV when the raster output scanner is off.

### Claim 18 (depends on 11)

The system defined in claim 11, wherein the exposure formula is:
Exposure
=
1
S
⁡
[
(
(

Vc

-

Vr

)
2
-

Vt

2
(

Vc

-

Vr

)
)
-
(
(

Ve

-

Vr

)
2
-

Vt

2
(

Ve

-

Vr

)
)
]

### Claim 19 (depends on 17)

The system defined in claim 17, wherein:
the sensitivity coefficient S is defined as: S=S0*(1−e−k*|Vc|);
the transition point Vt is defined as: Vt=Vt0*|Vc|; and
the voltage image reading Ve is defined as: Ve=|Vr|+DR*(|Vc|−|Vr)|.

### Claim 20 (depends on 11)

The system defined in claim 11, wherein the printing machine comprises a xerographic printing machine.