US4707122A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for eliminating exposure strobing effects in a document reproduction machine
Assignee: Xerox Corp
•
Filing: 1986-09-24
•
Granted: 1987-11-17
•
Expires: 2006-09-24
Abstract
Abstract Exposure modulation (strobing) at a photoreceptor surface due to mechanical vibration of the photoconductor is eliminated by placing a filter with appropriate transmission characteristics in the optical path. The transmission characteristics necessary to achieve zero strobing include an incidence profile having a zero Fourier transform at the vibration frequencies.
Inventors
- 👤 William L. Lama
- 👤 Robert P. Loce
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:29
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/32; G03B27/52; G03B27/54; G03B27/542; G03G; G03G15/00; G03G15/04; G03G15/043; G03G15/0435
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
In a document scanning system wherein a plurality of optical components illuminates a document on an object plane and projects an image thereof along an optical path onto a photoconductor moving at a predetermined speed, the incident irradiance profile at the photoreceptor having a spatial variation across the surface defined by the expression H 1 (x), said system acquiring, during scan, a speed vibration of frequency f, giving rise to an exposure modulation at the photoreceptor surface given by the expression: ##EQU11## where m (the magnitude of the velocity modulation)=2πfΔ/V o , V o is the average process velocity, Δ is the amplitude of the spatial vibration and H(f/V o ) is the Fourier transform of the illumination profile at the strobing spatial frequency, the improvement comprising a variable density filter disposed along the optical path having transmission characteristics such that the Fourier transformed function H 1 (f/V o )=zero.
Claim 2
Dependent Claim
150 words
In a document scanning system wherein a plurality of optical components illuminates a document on an object plane and projects an image thereof along an optical path onto a photoconductor moving at a predetermined speed, the incident irradiance profile at the photoreceptor having a spatial variation across the surface defined by the expression H 1 (x), said system acquiring, during scan, a speed vibration of frequency f, giving rise to an exposure modulation at the photoreceptor surface given by the expression: ##EQU11## where m (the magnitude of the velocity modulation)=2πfΔ/V o , V o is the average process velocity, Δ is the amplitude of the spatial vibration and H(f/V o ) is the Fourier transform of the illumination profile at the strobing spatial frequency, the improvement comprising a variable density filter disposed along the optical path having transmission characteristics such that the Fourier transformed function H 1 (f/V o )=zero.
Claim 3
Dependent Claim
49 words
The system of claim 1 wherein the photoconductor is subject to vibrations at more than one frequency f i (i=1, . . . N) and wherein the variable density filter disposed along the optical path has the characteristic H(f i /V o )=0 for each frequency f i .
Claim 4
Dependent Claim
50 words
The system of claim 1 wherein the photoconductor is subject to vibrations at the frequencies f i as well as irradiance modulation at frequency a, and wherein the variable density filter disposed along the optical path has the spatial frequency characteristics described by H(±a/V.sub.o)=0 H(±f.sub.i /V.sub.o)=0, for each f.sub.i ##EQU12##
Claim 5
Dependent Claim
148 words
In a document scanning system wherein a plurality of optical components illuminates a document on an object plane and projects an image thereof along an optical path onto a photoconductor moving at a predetermined speed, the incident irradiance profile at the photoreceptor having a spatial variation across the surface defined by the expression H 1 (x), said system acquiring, during scan, a speed vibration of frequency f, giving rise to an exposure modulation at the photoreceptor surface given by the expression: ##EQU13## where m (the magnitude of the velocity modulation)=2πfΔ/V o , V o is the average process velocity, Δ is the amplitude of the spatial vibration and H(f/V o ) is the Fourier transform of the illumination profile at the strobing spatial frequency, the improvement comprising a reflector disposed along the optical path having reflectance characteristics such that the Fourier transformed function H 1 (f/V o )=zero.
Claim 6
Dependent Claim
148 words
In a document scanning system wherein a plurality of optical components illuminates a document on an object plane and projects an image thereof along an optical path onto a photoconductor moving at a predetermined speed, the incident irradiance profile at the photoreceptor having a spatial variation across the surface defined by the expression H 1 (x), said system acquiring, during scan, a speed vibration of frequency f, giving rise to an exposure modulation at the photoreceptor surface given by the expression: ##EQU13## where m (the magnitude of the velocity modulation)=2πfΔ/V o , V o is the average process velocity, Δ is the amplitude of the spatial vibration and H(f/V o ) is the Fourier transform of the illumination profile at the strobing spatial frequency, the improvement comprising a reflector disposed along the optical path having reflectance characteristics such that the Fourier transformed function H 1 (f/V o )=zero.
References Cited (Backward Citations)
US865324A
Cited
US3488118A
Cited
US3466127A
Cited
US3967894A
Cited
US3998539A
Cited
US4132477A
Cited
US4226527A
Cited
US4305650A
Cited
US4355891A
Cited
US4533238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |