Browse Prior Art Database

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

IP.com Disclosure Number: IPCOM000025561D
Original Publication Date: 1986-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 8 page(s) / 170K

Publishing Venue

Xerox Disclosure Journal

Abstract

Figures 1 through 10, inclusive, describe various circuits for measuring electrical currents from high voltage sources. In an electrophotographic printing machine, the development system employs a developability control system which measures the developer roll bias current.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 60% of the total text.

Page 1 of 8

XEROX DISCLOSURE JOURNAL

CURRENT MEASUREMENT TECHNIQUES Proposed Classification FORDEVELOPERROLLCURRENT U.S. C1. 118/637 Jeffrey J. Foklins Int. C1. B05b 5/02

  CURRENT MfASUREMENT lo

I DEVELOPER ROLL

I VOLTAGE OUTPUT L

- - - - - - - -+ TO PROCESSOR OR

CONTROL

CONSTANT CURRENT 10

SOURCE

VOLTAGE OUTPUT

+ TO PROCESSOR OR

CONTROL

FIG. I

" H I G H E R

VOLTAGE

SOURCE

BIAS - - POWER flu

SUPPLY

I

FIG. 2

Volume 11 Number 2 March/Aprrl 1986 51

- - ------

LOW VOLTAGE CURRENT MEASUREMENT

[This page contains 1 picture or other non-text object]

Page 2 of 8

CURRENT MEASUREMENT TECHNIQUE5 FOR DEVELOPER ROLL CURRENT

(Con t'd)

<,I REFERENCE /

- I

- POWER

- SUPPLY

T

Y DONORROLL

CHARGE ROLL

  XEROX DISCLOSURE JOURNAL Volume 11 Number 2 March/April 1986

52

[This page contains 1 picture or other non-text object]

Page 3 of 8

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

(Con t 'd )

4

P-_----

I CR4

FIG. 5 7 b Q

I

10

6 NG. 3

  XEROX DISCLOSURE JOURNAL Volume 11 Number 2 March/April 1986 53

[This page contains 1 picture or other non-text object]

Page 4 of 8

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

(Con t'd)

BIAS POWER

i2

10MEG

IOMEG

$

A7

Q

* 1x1

a3140

820K

MlCROPROCESSOR 5v Fv

AiDOF

4 FIG. 7

54

  XEROX DISCLOSURE JOURNAL Volume I1 Number 2 March/April 1986

[This page contains 1 picture or other non-text object]

Page 5 of 8

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

(Con t 'd)

CONTROLS TO s

FIG. 9

  XEROX DISCLOSURE JOURNAL Volume I1 Number 2 March/April 1986 55

[This page contains 1 picture or other non-text object]

Page 6 of 8

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

(Con t ' d )

CONSTANT CURRENT

4 REFERENCE

4,

CR5

DEVELOPER ROLL

- - - - - - - - - - + CONTROLS

    LOW VOLTAGE CURRENT MEASUREMENT

FlC. 8

-

  VERY HIGH VOLTAGE POWER SUPPLY

CR5

DEVELOPER ROLL

b

0 FIG. 10

56

  XEROX DISCLOSURE JOURNAL Volume 11 Number 2 March/April 1986

[This page contains 1 picture or other non-text object]

Page 7 of 8

CURRENT MEASUREMENT TECHNIQUES FOR DEVELOPER ROLL CURRENT

(Con t Id)

Figures 1 through 10, inclusive, describe various circuits for measuring electrical currents from high voltage sources. In an electrophotographic printing machine, the development system employs a developability control system which measures the developer roll bias current.

Figure I shows the intent of the system to measure the bias current of developer roll 10.

Figure 2 shows the basic configuration of the design, Developer roll 10 IS connected to both a constant current source supplying a reference current and to the emitter of a transistor. The transistor maintains the emitter voltage slightly above the supply voltage applied to the transistor base. The sum of the reference current and the developer roll bias current is equal to the current into the emitter. If the transistor has a sufficiently high current gain and a low l...