Browse Prior Art Database

DEVELOPED DENSITY MONITOR

IP.com Disclosure Number: IPCOM000024024D
Original Publication Date: 1979-Jun-30
Included in the Prior Art Database: 2004-Apr-01
Document File: 2 page(s) / 346K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a toner concentration monitoring and control system for a copier with a translucent photoreceptor and rear (backside) pre-transfer (and/or pre-clean) illumination of the photoreceptor. Referring to the example in Figures 1 and 2, a

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XEROX DISCLOSURE JOURNAL

DEVELOPED DENSITY MONITOR

Brian E. Springett

8

Proposed Classification

U.S. CL 355/14

mt. CL G03g 15/00

Disclosed is a toner concentration monitoring and control system for a copier with a translucent photoreceptor and rear (backside) pre-transfer (and/or pre-clean) illumination of the photoreceptor. Referring to the example in Figures 1 and 2, a

strip lamp 1 or other light source floods the translucent photoreceptor 2 in the pre- transfer area 3 and also in the post-transfer pre-clean area 4 (i.e., after most of the toner has normally been transferred to the copy sheet 5 in the transfer area 6). In the pre-transfer area 3, two conventional photosensors 7 and 7a (7a is hidden behind 7 in Figure 1) detect the light passing through the photoreceptor 2. As

shown in Figure 2, the photodector 7 is located over an edge of the photoreceptor which is never developed, so that it measures a zero-toner-density area of the photoreceptor at all times while the comparative photosensor 7a overlies the copy

area of the photoreceptor 2. Thus, as the photoreceptor 2 moves through the pre- development area 3 bearing developed toner images thereon (developed at the developer station 8), the light from the lamp 1 will be partially obstructed by the toner in those areas from reaching the photosensor 7a, Thus, by applying the outputs of these two photodetectors 7 and 7a to a comparator circuit 9, an output 10 is provided which may be connected to control the developer unit 8 or a toner dispenser thereto or the voltage level applied to the photoreceptor charging unit

11. A significant rise in the output level of the photodetector 7a towards the output level of the photod...