EP0575162A1
Expired / Lapsed
EP
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Method and apparatus for correction of color registration errors
Assignee: Xerox Corp
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Filing: 1993-06-16
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Granted: —
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Expires: 2013-06-16
Abstract
Abstract An image alignment apparatus for an imaging apparatus which includes at least two printers arranged to print in alignment on a process medium. The apparatus includes a control system which includes a marking device for applying to the process medium a first chevron (KK1,KK2) from a first printer, a second chevron (MM1,MM2) from a second printer and a third chevron (KM1,KM2) from both the first printer and the second printer. The control system further includes a detection device (D1,D2) for detecting a matrix of times including three pluralities of times, each of the three pluralities of times corresponding to a time of passage of a respective one of the first, second and third chevrons by the detection device, a determining device for determining an alignment error based on a function of the matrix of times, and a control device for minimizing the alignment error.
Inventors
- 👤 Joannes N.M. De Jong
- 👤 Vittorio R. Castelli
- 👤 Harold M. Anderson
- 👤 Lloyd Williams
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:35
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/50; H04N1/506; G; G03; G03G; G03G15/00; G03G15/01; G03G15/0142; G03G15/0178; G03G15/0194; G03G2215/00; G03G2215/01; G03G2215/0103; G03G2215/0119
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
Imaging apparatus including at least two printers arranged to print in alignment on a process medium, and sensing means for sensing an alignment error between a first printer and a second printer, the sensing means including, marking means for applying to the process medium a first pattern from the first printer, a second pattern from the second printer and a third pattern from both the first printer and the second printer, the third pattern having a first element applied from the first printer and a second element applied from the second printer, detection means for detecting a matrix of times comprising three pluralities of times, each of the three plurality of times corresponding to a respective time of passage of said first, second and third patterns by said detection means, and determining means for determining the alignment error based on a function of the three pluralities of times.
Claim 2
Dependent Claim
21 words
The apparatus of claim 1 including control means responsive to said alignment error to control the apparatus to minimize the error.
Claim 3
Dependent Claim
47 words
The control system of claim 2, wherein said control means includes means for controlling a rotating velocity of an element of the first printer or the second printer relative to a rotational velocity of an element of the other printer so that the alignment error is minimized.
Claim 4
Dependent Claim
53 words
The apparatus of claim 2 or claim 3 wherein the control means includes, calibrating means for producing a calibration table representative of a repeatable component of the alignment error as a function of a rotation phase angle, and correction means for minimizing the alignment error based on a function of the calibration table.
Claim 5
Independent Claim
179 words
The apparatus of any one of claims 1 to 4, wherein: the first and second patterns each include a first element and a second element; the three pluralities of time each include a first time and a second time; said detection means detects a first set of three times, each time of the first set of three times corresponding to the first time of each of the three pluralities of times and the first time of each of the three pluralities of times corresponding to a time of passage of the first element of a respective one of said first, second and third patterns by said detection means; and said detection means further detects a second set of three times, each time of the second set of three times corresponding to the second time of each of the three pluralities of times and the second time of each of the three pluralities of times corresponding to a time of passage of the second element of a respective one of said first, second and third patterns by said detection means.
Claim 6
Dependent Claim
32 words
The alignment system of claim 5, wherein said determining means determines the alignment error based on a function of the first set of three times and the second set of three times.
Claim 7
Independent Claim
126 words
The apparatus of any one of claims 1 to 6, wherein: the detection means further detects an additional alignment error between a third printer and the first printer and the mark further has a fourth pattern from the third printer and a fifth pattern from both the third printer and the first printer, the fifth pattern having a first element applied from the third printer and a second element applied from the first printer; the matrix of times further comprise a fourth and a fifth plurality of times corresponding to a respective time of passage of the fourth and fifth patterns by said detection means; and said determining means includes means for determining the additional alignment error based on a function of the matrix of times.
Claim 8
Independent Claim
44 words
The apparatus of any one of claims 1 to 6 further comprising a raster output scanner for writing image data to one or more of the printers, wherein the correction means controls a rate of the image data written by the raster output scanner.
Claim 9
Dependent Claim
86 words
Imaging apparatus including: at least two printers arranged to print in alignment on a process medium; sensing means for sensing an alignment error between a first printer and a second printer; and control means for minimizing the alignment error, the control means including, calibration means for producing a calibration table representative of a repeatable rotational phase angle dependent component of the alignment error as a function of rotational phase angle, and correction means for minimizing the alignment error based on a function of the calibration table.
Claim 10
Dependent Claim
57 words
A control system in a machine for minimizing an alignment error between a first rotating member and a second rotating member, the control system comprising: calibration means for producing a calibration table representative of a repeatable component of the alignment error, and correction means for minimizing the alignment error based on a function of the calibration table.
Claim 11
Dependent Claim
78 words
A control system for controlling alignment between printers in a process direction, the control system comprising: detection means for detecting a plurality of times corresponding to a time of passage of a plurality of registration marks on a process medium by said detection means; determining means for determining an alignment error in a process direction based on a function of the plurality of times; and control means for controlling a printer rotational velocity to minimize the alignment error.
References Cited (Backward Citations)
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