Patents by Inventor Mahesan Chelvayohan

Mahesan Chelvayohan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6794669
    Abstract: A media sensing apparatus includes a media sensor including a light source for generating a light beam, and a diffuse detector positioned in relation to the light source for detecting diffuse light components reflected from a sheet of print media. A media support is provided having a detection portion. The detection portion is located such that the media sensor faces the detection portion. The detection portion is configured to direct specular light components reflected from the detection portion to the diffuse detector in an absence of the sheet of print media being interposed between the media sensor and the detection portion.
    Type: Grant
    Filed: July 24, 2002
    Date of Patent: September 21, 2004
    Assignee: Lexmark International, Inc.
    Inventors: Mahesan Chelvayohan, Herman Anthony Smith, Charles Jarrett Simpson
  • Publication number: 20040135106
    Abstract: A media type sensing method for an imaging apparatus includes the steps of changing a light intensity of a light source by changing a drive signal, while monitoring for an output change of a comparator; determining a drive signal value of the drive signal at a point of detection of the output change; and correlating the drive signal value to a specific media type.
    Type: Application
    Filed: January 15, 2003
    Publication date: July 15, 2004
    Inventors: John Philip Bolash, Mahesan Chelvayohan, Patrick Laurence Kroger
  • Publication number: 20040119637
    Abstract: A gauge for detecting the level of ink in a printer's ink reservoir includes: a transmitter antenna adapted to be positioned adjacent to an outer surface of a printer's ink reservoir; a transmitter circuit operatively coupled to the transmitter antenna for generating a radio-frequency signal for transmission by the transmitter antenna; a receiver antenna; a receiver circuit for obtaining at least a portion of the radio-frequency signal received by the receiver antenna; and a processing circuit, operatively coupled to the receiver circuit, and configured to determine an approximate level of ink in the ink reservoir based upon, at least in part, a characteristic of the obtained portion of the radio-frequency signal, such as a voltage level of the obtained portion of the radio-frequency signal.
    Type: Application
    Filed: December 24, 2002
    Publication date: June 24, 2004
    Inventors: Aditya J. Angal, Mahesan Chelvayohan, Patrick L. Kroger, Herman A. Smith
  • Publication number: 20040114201
    Abstract: An imaging device has a print media path for transporting a print media sheet in a sheet feed direction. A mounting device is coupled to a frame. A media sensor has a body and at least one rotating member rotatably coupled to the body. The body is coupled to the mounting device. The mounting device is configured to facilitate movement of the media sensor in a direction toward the media path and to restrain movement of the media sensor in the sheet feed direction. The media sensor is positioned by the mounting device such that at least one rotating member rotates due to contact with a surface of the print media sheet as the print media sheet moves relative to the media sensor in the sheet feed direction along the print media path.
    Type: Application
    Filed: December 12, 2002
    Publication date: June 17, 2004
    Inventors: Mahesan Chelvayohan, Timothy Lorn Howard
  • Publication number: 20040099822
    Abstract: A method of media type differentiation includes the steps of providing a media sensor including a specular detector that provides a specular signal output having a signal level related to an amount of the reflected specular light received; providing a highly reflective surface positioned to face the media sensor; interposing a print media sheet between the media sensor and the highly reflective surface; using the media sensor to measure a first amount of the reflected specular light and determining a first signal level of the specular signal output of the specular detector; and using the first signal level to differentiate the print media sheet as being one of a transparency media sheet or a high glossy media sheet.
    Type: Application
    Filed: November 21, 2002
    Publication date: May 27, 2004
    Inventor: Mahesan Chelvayohan
  • Patent number: 6713775
    Abstract: A method of correcting for sensitivity variation of media sensors includes the steps of determining a first reflectance ratio of a first calibration media having a first glossiness; determining a second reflectance ratio of a second calibration media having a second glossiness, the second glossiness being greater than the first glossiness and determining a corrected normalized reflectance ratio of an unknown media based on the first reflectance ratio of the first calibration media and the second reflectance ratio of the second calibration media.
    Type: Grant
    Filed: June 21, 2002
    Date of Patent: March 30, 2004
    Assignee: Lexmark International, Inc.
    Inventors: Mahesan Chelvayohan, Timothy L. Anderson
  • Publication number: 20040017416
    Abstract: A media sensing apparatus includes a media sensor including a light source for generating a light beam, and a diffuse detector positioned in relation to the light source for detecting diffuse light components reflected from a sheet of print media. A media support is provided having a detection portion. The detection portion is located such that the media sensor faces the detection portion. The detection portion is configured to direct specular light components reflected from the detection portion to the diffuse detector in an absence of the sheet of print media being interposed between the media sensor and the detection portion.
    Type: Application
    Filed: July 24, 2002
    Publication date: January 29, 2004
    Inventors: Mahesan Chelvayohan, Herman Anthony Smith
  • Publication number: 20030234373
    Abstract: A method of correcting for sensitivity variation of media sensors includes the steps of determining a first reflectance ratio of a first calibration media having a first glossiness; determining a second reflectance ratio of a second calibration media having a second glossiness, the second glossiness being greater than the first glossiness and determining a corrected normalized reflectance ratio of an unknown media based on the first reflectance ratio of the first calibration media and the second reflectance ratio of the second calibration media.
    Type: Application
    Filed: June 21, 2002
    Publication date: December 25, 2003
    Inventors: Mahesan Chelvayohan, Timothy L. Anderson
  • Patent number: 6590223
    Abstract: Media manipulation and sensing apparatuses including a media detector and method for media detection, wherein a light source and/or light sensor of a media detector is blocked using a light blocking mechanism, such that the detected light intensity of the light sensor is effectively zero. The media detector having such a media blocking mechanism may also be used for media type detection.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: July 8, 2003
    Assignee: Lexmark International, Inc.
    Inventor: Mahesan Chelvayohan
  • Patent number: 6360582
    Abstract: Changes in the concentration of a chemical, such as a gas, are determined using a non-linear chemical sensor which is subject to shifts in calibration over time. In order to minimize errors caused by such shifts in calibration a first infrared signal (Ig(1)) is measured and using an absorption value under an assumed chemical concentration (C(1)), a zero chemical signal Io(1) is calculated using the known physical law and mathematical relation Absorption=1−Ig/Io. A second infrared signal (Ig(2)) is then measured and the absorption value is calculated using the previously calculated zero chemical signal. A second concentration (C(2)) is then determined and the change in concentration is calculated by subtracting C(2) from C(1).
    Type: Grant
    Filed: January 18, 2000
    Date of Patent: March 26, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Mahesan Chelvayohan, Patrick L. Kroger
  • Patent number: 6067840
    Abstract: A gas sensor (10) is shown having alternately energized infrared radiation sources (14, 16) disposed in a gas chamber (12) at different distances from an infrared detector (18). Both radiation sources are filtered at the absorbing wavelength of a gas to be monitored with one radiation source located proximate to the detector serving as a "virtual reference". The differential absorption between the two radiation sources is used to determine the concentration of a gas being monitored. In a modified sensor (30) one radiation source is seated in a parabolic recess (34a) in a base plate (34) with the radiation focused on one angled end wall (32d) of a dished shaped cover member (32) and reflected over to a second angled end wall (32e) and into the detector with the radiation sources and the detector attached directly to a circuit board (24) mounting the sensor.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: May 30, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Mahesan Chelvayohan, Adam J. Ahne
  • Patent number: 5635136
    Abstract: A combustible gas sensor having a noble metal sensor element with a surface that is heated above a critical temperature at which the surface is able to dissociate oxygen in a gas stream and adsorb the oxygen onto its surface. The adsorbed oxygen present on the noble metal surface enhances the reactivity of the sensor element and permits it to react with combustible gases that otherwise would have little or no affinity for the sensor element. The balance of adsorbed oxygen and combustible gas species on the sensor surface cause a change in an electrical property that is used to determine the presence or identity of a combustible gas, or to derive a concentration measurement.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: June 3, 1997
    Assignee: Arizona Board of Regents
    Inventors: William Glaunsinger, Ian Sorensen, Mahesan Chelvayohan
  • Patent number: 5521099
    Abstract: A combustible gas sensor having a noble metal sensor element with a surface that is heated above a critical temperature at which the surface is able to dissociate oxygen in a gas stream and adsorb the oxygen onto its surface. The adsorbed oxygen present on the noble metal surface enhances the reactivity of the sensor element and permits it to react with combustible gases that otherwise would have little or no affinity for the sensor element. The balance of adsorbed oxygen and combustible gas species on the sensor surface cause a change in an electrical property that is used to determine the presence or identity of a combustible gas, or to derive a concentration measurement.
    Type: Grant
    Filed: September 23, 1994
    Date of Patent: May 28, 1996
    Assignee: Arizona Board of Regents
    Inventors: William Glaunsinger, Ian Sorensen, Mahesan Chelvayohan