XEROGRAPHIC BACKGROUND SAMPLING APPARATUS

Publishing Venue

Xerox Disclosure Journal

Abstract

In the xerographic process, it is important to keep the size of background particles (those in the non-4nformational areas of the latent image) to a minimum for good copy quality. When a plurality of background measurements are desired on a photoreceptor containing many images, it is important that the samples are taken in the background areas and not in those solid areas representing information or interimage areas on the photoreceptor.

XEROX DISCLOSURE JOURNAL

XEROGRAPHIC BACKGROUND SAMPLING

APPARATUS Robert E. Grace

Proposed Classification
U.S. Cl. 355/3

mt. Cl. G03g 15/00

FIG. 1

Volume 4 Number 4 ~uiy/August 1979 491

~TOME~R+

CCD ARRAY

In the xerographic process, it is important to keep the size of background particles (those in the non-4nformational areas of the latent image) to a minimum for good

copy quality. When a plurality of background measurements are desired on a photoreceptor containing many images, it is important that the samples are taken in the background areas and not in those solid areas representing information or interimage areas on the photoreceptor.

A reflectance densitometer can be used in front of a CCD array as shown in Figure
1. The densitometer I. and array 2 are positioned above the photoreceptor, preferably toward one edge of the image 3 portion. The densitometer would sense both light and dark areas on the photoreceptor 4 with the light areas representing background and the dark areas representing information portions of the developed image on the photoreceptor. The output of the densitometer will vary accordingly.

J

REFERE~E

FIG. 2

XEROGRAPHIC BACKGROUND SAMPLING APPARATUS (Cont~d)

Referring to Figure 2, the densitometer output is compared with a reference signal of a predetermined level representing the background area output of the densitometer. When the densitometer signal corresponds closely to...