Array based sensor to measure single separation or mixed color (or IOI) patches on the photoreceptor using MEMS based hyperspectral imaging technology

#This application is related to U.S. patent application Ser. No. 10/248,387, filed on 15 Jan. 2003, and entitled, “Systems and Methods for Obtaining a Spatial Color Profile and Calibrating a Marking System;” U.S. patent application Ser. No. 10/342,873, filed on 15 Jan. 2003, and entitled, “Iterative Printer Control and Color Balancing System and Method Using a High Quantization Resolution Halftone Array to Achieve Improved Image Quality with Reduced Processing Overhead;” U.S. patent application Ser. No. 09/566,291, filed on 5 May 2000, and entitled, “Online Calibration System for a Dynamically Varying Color Marking Device;” U.S. patent application Ser. No. 11/070,681, filed on 2 Mar. 2005, and entitled, “Gray Balance for a Printing System of Multiple Marking Engines;” U.S. patent application Ser. No. 11/097,727, filed on 31 Mar. 2005, and entitled, “Online Gray Balance Method with Dynamic Highlight and Shadow Controls;” U.S. patent application Ser. No. 11/428,489, filed 3 Jul. 2006 and entitled, “Pitch-to-Pitch Online Array Balance Calibration;” and U.S. Pat. No. 6,295,130, filed on 22 Dec. 1999, and entitled, “Structure and Method for a Microelectromechanically Tunable Fabry-Perot Cavity Spectrophotometer;” U.S. Pat. No. 6,975,949, filed on 13 Dec. 2005, and entitled, “Full Width Array Scanning Spectrophotometer;” U.S. Pat. No. 6,690,471, filed on 10 Feb. 2004, and entitled, “Color Imager Bar Based Spectrophotometer for Color Printer Color Control System;” U.S. patent application Ser. No. 11/535,385, filed 26 Sep. 2006 and entitled, “Color Sensor to Measure Single Separation, mixed Color or IOI patches;” U.S. patent application Ser. No. 11/535,382 filed 26 Sep. 2006 and entitled, “Mems Fabry-Perot Inline Color Scanner For Printing Applications Using Stationary Membranes;” and U.S. patent application Ser. No. 11/016,952, filed Dec. 20, 2004 and entitled, “Full Width Array Mechanically Tunable Spectrophotometer.” The disclosures of the related applications are incorporated by reference in their entirety.

#This disclosure generally relates to light sensor devices for use in marking methods and systems.

#This disclosure refers to “marking” as a process of producing a pattern, such as text and/or images, on substrates, such as paper or transparent plastic. A marking engine may perform the actual marking by depositing ink, toner, dye, or any other suitable marking material on the substrate. For brevity, the word “toner” will be used to represent the full range of marking materials, and is used interchangeably with the terms for other identifying materials in the full range of marking materials.

#Exemplary embodiments will be disclosed with reference to the accompanying drawings, in which like numerals represent like parts, and wherein:

#FIG. 1 schematically illustrates an Image On Image (IOI) marking engine showing multiple pitches on a photoreceptor belt;

#FIG. 2 schematically illustrates a tandem marking engine showing multiple pitches on an intermediate transfer belt (ITB);

#To obtain a desired color on a target media, such as white paper, different amounts of base colors or marking materials, such as cyan, magenta and yellow, are marked on a photoreceptor unit or belt in preparation for transfer to the target media. A well-balanced marking engine should produce a pitch with color reflectance values which, when measured, match reflectance values that correspond to the desired color. However, a marking engine may not produce an exact desired color due to, among other factors, variations in color pigments of the primary colors used by the marking engine, and/or internal processes of the marking engine. To overcome such shortfalls, color balance TRCs may be developed by iterative methods, such as those described above, and as disclosed in U.S. patent applications Ser. Nos. 09/566,291, 11/070,681 and 11/097,727. These TRCs maybe employed to, for example, adjust amounts of cyan, magenta and yellow proportions for all color tone values, taking into account the state of the materials and the marking engine. This approach can be extended to produce color balanced and/or gray balanced TRCs for spatial uniformity corrections as disclosed, for example, in U.S. patent applications Ser. Nos. 10/248,387 and 10/342,873.

#Iterative methods disclosed above to produce accurate TRCs may rely upon feedback in the form of measured reflectance values from toned patches output by the marking engine in response to a set of predetermined, often stored, toned patch pattern data. By comparing measured spectral information from a toned patch with a stored set of desired spectral information previously generated for the toned patch, TRCs may be created and/or updated. The new or updated TRCs may then be used by the marking engine to adjust and stabilize color output. However, measured reflectance values provided by the spectrophotometers used in the above processes includes limited spectral information, as discussed above.

#Calibration and control methodologies disclosed above may be used to achieve high quality and consistent color balanced printing for marking engines with periodic pitch-to-pitch variations. To counter the effects of such factors as temperature, humidity, the age and/or amount of use of the photoreceptor belt, age and/or use of an individual toner color and other such related factors, TRCs are preferably continuously updated based upon measured spectral information that is measured one or more times during a single revolution of a marking system's photoreceptor belt. As discussed above, exemplary embodiments of disclosed Fabry-Perot array sensor devices can provide improved spectral information in support of such color stabilization processes. One exemplary embodiment may obtain improved spectral information from toned patches and/or images on a photoreceptor belt within a marking system, allowing spectral information to be collected each revolution, without introducing ghost images upon the photoreceptor belt. Another exemplary embodiment may obtain spectral information from toned patches and/or images on a non-photosensitive output substrate, such as an intermediate belt or paper.