Illuminator calibrations for media edge detections

Patent metadata

Field	Value
Publication number	US-11712906-B2
Application number	US-201716763021-A
Country	US
Kind code	B2
Filing date	Nov 17, 2017
Priority date	Nov 17, 2017
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

An apparatus including an illuminator to emit light on a media to be printed on is provided. The apparatus also includes an optical sensor disposed proximate to the illuminator to detect an amount of reflected light. In addition, the apparatus includes a processor to control the illuminator and the optical sensor. The processor is to calibrate the illuminator to determine a first brightness level for high sensitivity at the optical sensor. The processor is to calibrate the illuminator to determine a second brightness level iteratively based on a signal to noise ratio. The processor is to compare the second brightness level with the first brightness level to determine whether to proceed with detection of an edge of the media using the second brightness level.

First claim

What is claimed is:

1. An apparatus comprising:
an illuminator to emit light on a media to be printed on;
an optical sensor disposed proximate to the illuminator to detect an amount of reflected light; and
a processor to control the illuminator and the optical sensor, wherein the processor is to:
calibrate the illuminator to determine a first brightness level for high sensitivity at the optical sensor while the illuminator is positioned over the media;
calibrate the illuminator to determine a second brightness level iteratively based on a signal to noise ratio while the illuminator is positioned over an absorber;
set a brightness of the illuminator to the second brightness level in response to the second brightness level exceeding a brightness threshold; and
proceed with detection of an edge of the media using the second brightness level of the illuminator.

2. The apparatus of claim 1 , further comprising a cover to protect the optical sensor and the illuminator.

3. The apparatus of claim 1 , further comprising:
a guide bar; and
a carriage slidably mounted on the guide bar, wherein the carriage supports the illuminator and the optical sensor.

4. The apparatus of claim 3 , further comprising a printhead mounted on the carriage, wherein the printhead is mounted at a fixed relative position to the illuminator and the optical sensor.

5. The apparatus of claim 1 , wherein processor is to receive an input representing a media size, the processor to verify the input corresponds with the edge detected.

6. The apparatus of claim 1 , wherein the absorber is an absorbing material to absorb light emitted from the illuminator to reduce reflected light back to the optical sensor.

7. The apparatus of claim 1 , wherein the absorber is a platen of the apparatus.

8. A method comprising:
emitting light using an illuminator onto a media to be printed on;
measuring reflected light from the illuminator using an optical sensor;
generating reflectance data based on the reflected light measured by the optical sensor;
determining a first brightness level while the illuminator is positioned over the media at which the illuminator emits light such that the reflected light is within a reflected brightness range corresponding to a high sensitivity range of the optical sensor;
determining a second brightness level while the illuminator is positioned over an absorber at which the illuminator emits light such that the reflected brightness range is below a predetermined signal to noise ratio threshold;
setting a brightness of the illuminator to the second brightness level in response to the second brightness level exceeding a brightness threshold; and
proceeding with detection of an edge of the media using the second brightness level of the illuminator.

9. The method of claim 8 , further comprising mounting the illuminator and the optical sensor on a carriage, wherein the carriage is slidable along a guide bar.

10. The method of claim 9 , further comprising mounting a printhead on the carriage, wherein the printhead is mounted at a fixed relative position to the illuminator and the optical sensor.

11. The method of claim 10 , wherein the carriage is movable along the guide bar between a first position to determine the first brightness level and a second position to determine the second brightness level.

12. The method of claim 11 , wherein the first position is over the media and the second position is over the absorber.

13. The method of claim 8 , wherein determining a first brightness level comprises adjusting the reflected brightness range to be within a substantially linear response region of the optical sensor.

14. The method of claim 13 , wherein determining a second brightness level comprises increasing the reflected brightness range iteratively until the predetermined signal to noise ratio threshold is reached.

15. The method of claim 8 , further comprising:
receiving an input representing a media size; and
verifying the input corresponds with a detected edge.

16. A non-transitory machine-readable storage medium encoded with instructions executable by a processor, the non-transitory machine-readable storage medium comprising:
instructions to emit light on a media to be printed on using an illuminator;
instructions to receive reflectance data from an optical sensor, wherein the reflectance data represents an amount of reflected light received at the optical sensor from the media;
instructions to determine a first brightness level while the illuminator is positioned over the media at which the illuminator emits light such that the reflectance data is in a high sensitivity range;
instructions to determine a second brightness level while the illuminator is positioned over an absorber at which the illuminator emits light such that the reflectance data is below a predetermined signal to noise ratio threshold;
instructions to set a brightness of the illuminator to the second brightness level in response to the second brightness level exceeding a brightness threshold; and
instructions to proceed with detection of an edge of the media using the second brightness level of the illuminator.

17. The non-transitory machine-readable storage medium of claim 16 , further comprising instructions to receive an input representing a media size, and instructions to verify that the input corresponds with a detected edge.

Assignees

• Hewlett Packard Development Co

Inventors

• Low Tong Nam Samuel
• Zhao Yu
• Huang Xiaoxi

Classifications

• B41J11/0095 Primary

  Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end · CPC title

• H04N1/00034

  Measuring, i.e. determining a quantity by comparison with a standard (H04N1/00031 takes precedence) · CPC title

• H04N1/00087

  Setting or calibrating (picture signal circuits H04N1/40) · CPC title

• H04N1/00655

  Apparatus in common for different handling operations (H04N1/00575, H04N1/00594, H04N1/00596, H04N1/00618 take precedence) · CPC title

• B41J29/38 Primary

  Drives, motors, controls or automatic cut-off devices for the entire printing mechanism · CPC title