Apparatus and method for media presence detection

• US 6,590,223 B1
• Filed: 07/03/2001
• Issued: 07/08/2003
• Est. Priority Date: 07/03/2001
• Status: Expired due to Term

• Current Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Original Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Inventors: Chelvayohan, Mahesan
• Primary Examiner(s): Pyo, Kevin
• Assistant Examiner(s): Sohn, Seung C
• Application Number:
  US09/898,324
• Time in Patent Office: 735 Days
• Field of Search: 250/559.4, 250/559.11, 250/559.15, 250/559.16, 250/559.17, 250/559.18, 250/559.28, 356/446, 356/445, 356/433, 356/432, 356/448, 356/239.1, 356/601, 356/612, 349/16, 349/19, 271/258.01, 271/3.13
• US Class Current: 250/559.4
• CPC Class Codes: G01V 8/12 using one transmitter and one receiver

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.

Claims

1. A media manipulation apparatus, comprising:

a media detector including,

a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor, wherein the light blocking mechanism impedes propagation of light from a light source to block light from being detected by the first light sensor when a media is not present on the media path between the first light sensor and the light blocking mechanism; and

a determining unit to determine whether the media is present based on a detected light intensity of the first light sensor being effectively zero.

2. The media manipulation apparatus of claim 1, further comprising:

a second light sensor arranged in the media detector to detect specularly reflected light from the media, with the first light sensor being arranged to detect diffusely reflected light from the media; and

wherein the determining unit bases the determination of media presence on both first and second light sensors detecting effectively zero light intensity.

3. The media manipulation apparatus of claim 2, wherein the determining unit also determines a type of media present on the media path, when media is present, based on a ratio of detected light intensities of the first and second light sensors.

5. The media manipulation apparatus of claim 1, wherein the media detector is positioned such that the determination of whether media is present may be made without a picking operation of a picking mechanism being initiated.

4. A media manipulation apparatus, comprising:

a media detector including,

a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor, wherein the light blocking mechanism blocks light from being detected by the first light sensor when a media is not present on the media path between the first light sensor and the light blocking mechanism; and

a determining unit to determine whether the media is present based on a detected light intensity of the first light sensor being effectively zero,

wherein the light blocking mechanism is conformal with the shape of a light detecting area of the media detector, and recessed in a cavity beneath the media path, such that when media is not present on the media path between the light detecting area and the light blocking mechanism the light blocking mechanism mates with the light detecting area to block light from being detected by the first light sensor.

6. A media sensing apparatus, comprising:

a media detector including, a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor, wherein the light blocking mechanism impedes the propagation of light from a light source to block light from being detected by the first light sensor when a media is not present on the media path between the first light sensor and the light blocking mechanism; and

a determining unit to determine whether the media is present based on a detected light intensity of the first light sensor being effectively zero.

7. The media sensing apparatus of claim 6, further comprising:

a second light sensor arranged in the media detector to detect specularly reflected light from the media, with the first light sensor being arrange to detect diffusely reflected light from the media; and

wherein the determining unit bases the determination of media presence on both first and second light sensors detecting effectively zero light intensity.

8. The media sensing apparatus of claim 7, wherein the determining unit also determines a type of media present on the media path, when media is present, based on a ratio of detected light intensities of the first and second light sensors.

9. A media sensing apparatus, comprising:

a media detector including,

a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor, wherein the light blocking mechanism blocks light from being detected by the first light sensor when a media is not present on the media path between the first light sensor and the light blocking mechanism; and

a determining unit to determine whether the media is present based on a detected light intensity of the first light sensor being effectively zero,

wherein the light blocking mechanism is conformal with the shape of a light detecting area of the media detector, and recessed in a cavity beneath the media path, such that when media is not present on the media path between the light detecting area and the light blocking mechanism the light blocking mechanism mates with the light detecting area to block light from being detected by the first light sensor.

10. A media detector, comprising:

a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor,

wherein the light blocking mechanism impedes the propagation of light from a light source to block the first light sensor from detecting light when a media is not present on the media path between the first light sensor and the light blocking mechanism.

11. The media detector of claim 10, further comprising:

a second light sensor arranged to detect specularly reflected light from the media, with the first light sensor being arranged to detect diffusely reflected light from the media; and

a determining unit to determine whether the media is present based on both first and second light sensors detecting effectively zero light intensity.

12. The media detector of claim 11, wherein the determining unit also determines a media type of the media when the media is present, based on a ratio of detected light intensities of the first and second light sensors.

13. A media detector, comprising:

a first light sensor arranged on a top or bottom side of a media path; and

a light blocking mechanism arranged on an opposing side of the media path compared to the arrangement of the first light sensor,

wherein the light blocking mechanism blocks the first light sensor from detecting light when a media is not present on the media path between the first light sensor and the light blocking mechanism,

wherein the light blocking mechanism is conformal with the shape of a light detecting area of the media detector, and recessed in a cavity beneath the media path, such that when media is not present on the media path between the light detecting area and the light blocking mechanism the light blocking mechanism mates with the light detecting area to block light from being detected by the first light sensor.

14. The media detector of claim 13, wherein a protrusion extends from the conformal shape of the light blocking mechanism to enter a cavity of the media detector containing the first light sensor.

15. The media detector of claim 13, wherein a depression extends into the conformal shape of the light blocking mechanism to accept a portion of the first light sensor extending into the light detecting area of the media detector.

16. A media detection method for use with a media detector having a light source and a first light sensor to detect a light intensity of light reflecting off of a media that travels on a media path, with the light source and first light sensor being arranged on a top or bottom side of the media path, comprising:

impeding the propagation of light from the light source to block the first light sensor from detecting light by using a light blocking mechanism arranged on an opposing side of the media path, compared to the arrangement of the light source and first light sensor, when no media is present in the media path between the first light sensor and the light blocking mechanism; and

determining whether the media is present based on an intensity of the first light sensor being effectively zero.

17. The media detection method of claim 16, further comprising determining a media type of the media.

18. The media detection method of claim 16, wherein the impeding of light from the light source further includes a blocking of the light source from radiating light onto an area of the media path.

19. A media detection method for use with a media detector having a light source and a first light sensor to detect a light intensity of light reflecting off of a media that travels on a media path, with the light source and first light sensor being arranged on a top or bottom side of the media path, comprising:

impeding the propagation of light from the light source to block the light source from radiating light by using a light blocking mechanism arranged on an opposing side of the media path, compared to the arrangement of the light source and the first light sensor, when no media is present in the media path between the light source and the light blocking mechanism; and

determining whether the media is present based on an intensity of the first light sensor being effectively zero.

20. The media detection method of claim 19, further comprising determining a media type of the media.

21. A media detection method for use with a media detector having a light source and a first light sensor to detect a light intensity of light reflecting off of a media that travels on a media path, with the light source and first light sensor being arranged on a top or bottom side of the media path, comprising:

blocking the light source from radiating light onto an area of the media path area by using a light blocking mechanism arranged on an opposing side of the media path, compared to the arrangement of the light source and the first light sensor, when no media is present in the media path between the light source and the light blocking mechanism; and

determining whether the media is present based on an intensity of the first light sensor being effectively zero,

wherein the blocking of the light source by the light blocking mechanism also prevents light produced by other light sources to be detected by the first light sensor, such that the detected intensity of the first light source is effectively zero.