Fluid level sensing system and method having controlled surface pairs

• US 6,274,880 B1
• Filed: 07/31/1998
• Issued: 08/14/2001
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Walker, Ray Allen
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US09/127,234
• Time in Patent Office: 1,110 Days
• Field of Search: 250/577, 250/573, 250/904, 250/903, 340/618, 340/619, 732/90.R, 732/91, 356/379
• US Class Current: 250/577
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: G01F 23/2927 for several discrete levels, e.g. with more than one light-conducting sensing element

Abstract

The present invention is a fluid level sensing system which has a single light source for providing light rays and a single light receiving device for receiving the light rays. The fluid level sensing system also has a fluid container which has a plurality of controlled surfaces arranged on the fluid container. Each controlled surface exhibits a first reflected light characteristic if fluid within the fluid container is in contact with the controlled surface and a second reflected light characteristic if the fluid is not in contact with the controlled surface. The controlled surfaces are disposed on the fluid container so that the light rays from the single light source impinge upon each of the controlled surfaces to produce either the first or the second reflected light characteristics and are thereby detected by the light receiving device to determine the fluid level in the fluid container.

Claims

1. A fluid level sensing system, comprising:

a single light source for providing light rays;

a single light receiving device for receiving said light rays emanating from said single light source; and

a fluid container having a plurality of controlled surface pairs arranged vertically along an interior wall of said fluid container, each controlled surface having a first reflected light characteristic when a fluid within said fluid container is in contact with said controlled surface, and a second reflected light characteristic when said fluid is not in contact with said controlled surface;

wherein each of said plurality of controlled surface pairs is disposed on said fluid container so that said light rays from said single light source impinge upon said plurality of controlled surface pairs, each controlled surface pair producing one of said first or said second reflected light characteristics for detection by said single light receiving device to determine said fluid level in said fluid container.

2. The fluid level sensing system of claim 1 wherein said single light source and said single light receiving device are combined into a single fluid level detection device that both emits and receives said light rays.

3. The fluid level sensing system of claim 1 wherein each of said controlled surface pairs includes a first control surface and a second control surface, each first controlled surface being paired with, abutted to, and at an acute angle from a corresponding second control surface whereby said light rays upon reflection from said first controlled surfaces, reflect onto said second controlled surfaces to produce a plurality of reflected light rays into said single light receiving device.

4. The fluid level sensing system of claim 1 wherein said light receiving device receives a light intensity representing a sum of reflected light rays from each of said plurality of controlled surface pairs to produce a signal indicative of ink level in said fluid container.

5. The fluid level sensing system of claim 1 wherein said fluid container is a plurality of ink containers, each ink container having a plurality of controlled surface pairs, and wherein said single light receiving device is moved relative to said plurality of ink containers so that said single light source emits said light rays that selectively impinges on said controlled surface pairs and is received by said single light receiving device to selectively determine ink level in each of said plurality of ink containers.

6. An ink jet printing system, comprising:

an ink level detection device having an energy emitting portion and an energy receiving portion;

a plurality of ink jet printheads for selectively depositing an ink on print media;

plurality of ink containers, each of said ink containers being associated with an inkjet printhead of said plurality of inkjet printheads for providing said ink to said corresponding ink jet printhead with each of said plurality of ink containers having a plurality of controlled surface pairs arranged vertically along an interior side wall of the ink container; and

means for moving said ink level sensing device to said plurality of ink containers so that said energy emitting portion emits energy that selectively impinges each of said controlled surface pairs and is received by said energy receiving portion to selectively determine ink level information from each of said plurality of ink containers.

7. The ink jet printing system of claim 6 wherein each controlled surface has a first reflected light characteristic when said ink, within said ink container, is in contact with said controlled surface and a second reflected light characteristic when said ink is not in contact with said controlled surface.

8. An ink containment device for use with an ink jet printing system, said ink containment device including:

a housing for containing an ink, said housing having an interior wall;

a plurality of controlled surface pairs disposed along said interior wall of said housing, each controlled surface of said plurality of controlled surface pairs having a first reflected light characteristic when said ink is in contact with said controlled surface and a second reflected light characteristic when said ink is not in contact with said controlled surface; and

wherein each of said plurality of controlled surface pairs is disposed and arranged on said housing so that incident light rays impinging upon each of said plurality of controlled surface pairs produce one of said first or said second reflected light characteristics having a combined light intensity value based on ink level in said ink containment device.

9. A method for detecting a fluid level in a fluid container, said method comprising:

providing said fluid container wherein a plurality of controlled surface pairs of said fluid container are disposed vertically along an interior side wall of said fluid container, said plurality of controlled surface pairs being within detecting range of a fluid level sensing device;

emitting light rays incident on said plurality of controlled surface pairs;

reflecting said light rays off of each controlled surface wherein said fluid is not in contact with said controlled surface and returning said light rays as a plurality of reflected light rays back to a single light receiving device of said fluid level detecting device;

diffusing said light rays into said fluid wherein said fluid is in contact with said controlled surface;

determining said fluid level by said fluid level sensing device analyzing a total amount of said reflected light rays received by said light receiving device; and

sending a signal to a control device reporting said fluid level.