Patent US2857387A successfully refreshed from Google Patents.
Patent EP0547854A2 successfully refreshed from Google Patents.
EP0547854A2
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EP
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Method and apparatus for aligning multiple image print bars in a single pass system
Assignee: Xerox Corp
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Filing: 1992-12-14
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Granted: —
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Expires: 2012-12-14
Abstract
Abstract An image bar recording system which utilizes a plurality of LED image bars to provide a plurality of latent images which may subsequently be developed in different colors. The print bars are initially aligned so that each color image is precisely registered at the same relative position along the exposed area of a photoreceptor belt (46). The alignment is accomplished by adding non-image fiduciary pixels (51,55) to the ends of each print bar and by forming a pair of opposed alignment apertures (40,42) in the surface of the belt. Y-axis alignment of the print bars is accomplished by detecting edge locations of a first pixel (P 1 ) and using this location to select a centrally located fiduciary pixel (P F ). The X-axis alignment is then obtained by rotating the print bar to bring a second selected image pixel into alignment as sensed through a second aperture. Once the initial X and Y-axis alignments are complete, subsequent alignment is maintained through subsequent passes by checking the positions of the previously identified pixels as they advance past additional lead edge apertures formed in the process direction along the belt surface.
Inventors
- 👤 Stephen C. Corona
- 👤 George A. Charnitski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:57
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/047; B; B41; B41J; B41J2/00; B41J2/435; B41J2/447; B41J2/45; G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1238; G06K15/1242; G06K15/1247; G06K15/129; H04N1/46; H04N1/50; H04N1/506; H04N1/12; H04N1/19; H04N1/191; H04N1/192; H04N1/193; H04N2201/00; H04N2201/024; H04N2201/02406; H04N2201/02416; H04N2201/02425; H04N2201/02439; H04N2201/04; H04N2201/047; H04N2201/04701; H04N2201/0471; H04N2201/04715; H04N2201/04722; H04N2201/04729; H04N2201/04731; H04N2201/04732; H04N2201/04734; H04N2201/04749; H04N2201/04753; H04N2201/04755; H04N2201/04789; H04N2201/04791; H04N2201/04794; Y; Y10; Y10S; Y10S362/00; Y10S362/80
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
125 words
An imaging system for forming a plurality of images on a movable photoreceptor belt, including: a plurality of print bars (48,50,52) arranged adjacent to the photoreceptor belt (46), each print bar adapted to create an exposure pattern corresponding with one of said plurality of images, each said print bar having a plurality of centrally located light emitters (53) which are selectively energized to form latent image patterns on said belt and opposed groups of fiduciary emitters (51,55) adjacent said centrally-located emitters, said fiduciary emitters cooperating with a pair of alignment areas (40,42) formed on opposite sides of the belt width to establish an initial alignment position for each print bar so that each image printed by said print bar is in registration with subsequent images.
Claim 2
Dependent Claim
125 words
An imaging system for forming a plurality of images on a movable photoreceptor belt, including: a plurality of print bars (48,50,52) arranged adjacent to the photoreceptor belt (46), each print bar adapted to create an exposure pattern corresponding with one of said plurality of images, each said print bar having a plurality of centrally located light emitters (53) which are selectively energized to form latent image patterns on said belt and opposed groups of fiduciary emitters (51,55) adjacent said centrally-located emitters, said fiduciary emitters cooperating with a pair of alignment areas (40,42) formed on opposite sides of the belt width to establish an initial alignment position for each print bar so that each image printed by said print bar is in registration with subsequent images.
Claim 3
Dependent Claim
80 words
An imaging system as claimed in claim 1, including respective detecting means (62,64) associated with said groups of fiduciary emitters for detecting the position of selected ones of said fiduciary emitters when said groups are visible via alignment areas, and means (70) for moving each of said print bars in a transverse direction to establish a transverse registration for each bar and means (72) for rotating the print bar until the detected position signals from said detecting means are concurrent.
Claim 4
Dependent Claim
65 words
An imaging system as claimed in claim 1 or claim 2, wherein said belt includes additional alignment areas (90,92) in process direction alignment with one of the said pair of alignment apertures, said additional apertures defining the lead edges of associated image exposure frames and wherein the respective detecting means (62) is further adapted to generate edge sync signals during operation of the imaging system.
Claim 5
Independent Claim
186 words
A method for aligning the plurality of image print bars which are arranged adjacent a movable photoreceptor belt, so as to register multiple images formed by the print bars, the method comprising the steps of: forming first and second alignment areas (40,42) in non-image exposure edge areas of the belt (46), positioning at least first and second linear image print bars in image forming position with respect to the belt, each print bar having at least one row of linearly extending light emitting pixels, including a central pixel grouping (53) used to write successive image lines on the charged portion of the belt and end pixel groups (51,55) emitting radiation outside the imaging area, moving the belt until the radiation from the end pixel groups is detected via said alignment areas by photodetecting means (62,64), moving the first print bar (50), while the belt is stationary, in a transverse direction to es- tabiish a transverse axis alignment, and rotating the end of the print bar parallel to the process direction until coincidence of output signals is detected at both end pixel groups during dynamic belt motion.
Claim 6
Independent Claim
186 words
A method for aligning the plurality of image print bars which are arranged adjacent a movable photoreceptor belt, so as to register multiple images formed by the print bars, the method comprising the steps of: forming first and second alignment areas (40,42) in non-image exposure edge areas of the belt (46), positioning at least first and second linear image print bars in image forming position with respect to the belt, each print bar having at least one row of linearly extending light emitting pixels, including a central pixel grouping (53) used to write successive image lines on the charged portion of the belt and end pixel groups (51,55) emitting radiation outside the imaging area, moving the belt until the radiation from the end pixel groups is detected via said alignment areas by photodetecting means (62,64), moving the first print bar (50), while the belt is stationary, in a transverse direction to es- tabiish a transverse axis alignment, and rotating the end of the print bar parallel to the process direction until coincidence of output signals is detected at both end pixel groups during dynamic belt motion.
Claim 7
Dependent Claim
65 words
A method as claimed in claim 4, in which the step of moving the print bar comprises: moving the first print bar laterally until a centrally located fiduciary pixel (P F ) of a first one of the end of pixel groups (51) is identified so as to establish a transverse alignment of the first print bar, and entering said fiduciary pixel into system memory.
Claim 8
Dependent Claim
73 words
A method as claimed in claim 5, wherein said first alignment area (40) is defined by having an inboard edge parallel to a belt velocity vector, and wherein said first end pixel group is selectively activated from the outboard side of the group until a pixel is identified as being adjacent said inboard edge and wherein said print bar is moved laterally until said identified fiduciary pixel is moved to said reference position.
Claim 9
Dependent Claim
119 words
A method as claimed in claim 6, including the further steps of: selecting a fiduciary pixel which is located at the approximate center of said first alignment area, detecting the position of said fiduciary pixel and storing said position in memory, identifying a start of line exposure pixel (P w ) a predetermined distance from said edge identified pixel and storing said start of line exposure pixel in memory, monitoring the subsequent several positions of said fiduciary pixel following the photoreceptive cycle, comparing the subsequent position with said stored position and generating a compensation feedback signal when a misalignment is detected, and adjusting the alignment of said print bar to restore the initial alignment position of said print bar.
Claim 10
Independent Claim
66 words
A method as claimed in any one of claims 4 to 7, including the further steps of: forming additional alignment areas (90,92) in the process direction in alignment with said first alignment area, said additional alignment areas defining the lead edge of an associated image exposure area, and detecting passage of said additional alignment areas with the photodetecting means and generating an image page sync signal.
Claim 11
Independent Claim
56 words
A method as claimed in any one of claims 4 to 8, including the further step of maintaining registration during a printing operation by dynamically comparing signals from the end pixel groups as said alignment areas pass beneath said print bars and adjusting the transverse and/or process position of any print bar found to be misaligned.
Claim 12
Dependent Claim
92 words
A method as claimed in claim 5, wherein the first alignment area comprises three mutually inclined regions (80A,80B,80C) extending in the process direction, and including the steps of: measuring the time between detection of the first and second regions passing beneath said fiduciary pixel to establish a first time t 1 , measuring the time between detection of the second and third regions passing beneath said fiduciary pixel to establish a second time t 2 , and moving the print bar in a transverse direction until t 1 equals t 2 .
Claim 13
Independent Claim
118 words
A method of line-by-line exposure of a moving photoreceptor member (46) by means of a plurality of image print bars (48,50,52), each bar comprising a plurality of linearly arranged light emitting pixel elements (51,53,55) including the steps of: optically determining the location of a fiduciary pixel (P F ) outside of the exposure area and moving said print bar in the X and Y-axis until said fiduciary pixel is in a predetermined alignment position, storing the coordinates of said pixel registration in binary data format in selected memory, and monitoring the subsequent location of said print bars and detecting when said print bars are out of position and generating corrective signals to restore the initial fiduciary pixel relationship.
Claim 14
Independent Claim
118 words
A method of line-by-line exposure of a moving photoreceptor member (46) by means of a plurality of image print bars (48,50,52), each bar comprising a plurality of linearly arranged light emitting pixel elements (51,53,55) including the steps of: optically determining the location of a fiduciary pixel (P F ) outside of the exposure area and moving said print bar in the X and Y-axis until said fiduciary pixel is in a predetermined alignment position, storing the coordinates of said pixel registration in binary data format in selected memory, and monitoring the subsequent location of said print bars and detecting when said print bars are out of position and generating corrective signals to restore the initial fiduciary pixel relationship.
Claim 15
Dependent Claim
62 words
A linear image print bar having at least one row of light emitting elements, said at least one row having a central group (53) of light emitting elements which produce a radiation output of a first resolution, and a second and third group (51,55) of elements adjacent said central grouping, said second and third groupings having radiation outputs of a second resolution.
Claim 16
Dependent Claim
62 words
A linear image print bar having at least one row of light emitting elements, said at least one row having a central group (53) of light emitting elements which produce a radiation output of a first resolution, and a second and third group (51,55) of elements adjacent said central grouping, said second and third groupings having radiation outputs of a second resolution.
Claim 17
Dependent Claim
104 words
A linear image print bar for forming exposure image areas on a charged photoreceptive surface in response to video data image inputs, wherein the print bar has at least a first row of light emitting elements, said at least first row having a central array (53) of light emitting elements which are selectively addressed to form an exposed image area on said photoreceptor, and a second and third light emitting element array (51,55) adjacent and on both ends of said central array, the second and third arrays being selectively addressed to produce radiation outputs outside of the image areas for registration and alignment purposes.
Claim 18
Dependent Claim
104 words
A linear image print bar for forming exposure image areas on a charged photoreceptive surface in response to video data image inputs, wherein the print bar has at least a first row of light emitting elements, said at least first row having a central array (53) of light emitting elements which are selectively addressed to form an exposed image area on said photoreceptor, and a second and third light emitting element array (51,55) adjacent and on both ends of said central array, the second and third arrays being selectively addressed to produce radiation outputs outside of the image areas for registration and alignment purposes.
References Cited (Backward Citations)
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