Browse Prior Art Database

FLUORESCENT LAMP TEMPERATURE COMPENSATION

IP.com Disclosure Number: IPCOM000024853D
Original Publication Date: 1982-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 86K

Publishing Venue

Xerox Disclosure Journal

Abstract

This disclosure relates to a photocopier imaging system and describes a method of controlling exposure variations caused by operating temperature variations of the document illuminating light source. A typical light source in a copier, such as, a fluorescent lamp has a light output that varies as a founction $f operating temperature. For example, over a temperature span of 80 F to 120 F, the light output within a single scan can vary as much as +/- 20%, respectively.

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[EROX DISCLOSURE JOURNAL

FLUORESCENT LAMP TEMPERATURE COMPENSATION
Alvin Eng

Proposed Classification
U.S. C1. 355/8 Int. C1. G03g 15/28

FIG I

28>

                            POWER 24 SUPPLY

Volume 7 Number 3 May/June 1982 181

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

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FLUORESCENT LAMP TEMPERATURE COMPENSATION (Cont'd)

This disclosure relates to a photocopier imaging system and describes a method of controlling exposure variations caused by operating temperature variations of the document illuminating light source. A typical light source in a copier, such as, a fluorescent lamp has a light output that varies as a founction $f operating temperature. For example, over a temperature span of 80 F to 120 F, the light output within a single scan can vary as much as +/- 20%, respectively.

Figure 1 illustrates a portion of an illumination system wherein a glass platen 10 of a copier is to be illuminated by fluorescent lamp 12. Light from the lamp is directed through aperture 14 onto the underside of the platen.

Light reflected from the platen is directed along optical path 16, reflected via mirror 18 and enters the entrance pupil of lens 20. A sagittal stop plate 22 is positioned in front of lens 20. The stop is attached to bi-metallic strip device 24 via a link 26. Device 24 is connected to lamp control circuit 28. As described below, the position of plate 22 is adjusted upward or downward in response to lamp output and closes or opens the lens to compensate for the illumin...