System with ambient sensor for estimating printing supply consumption

• US 5,655,174 A
• Filed: 05/22/1996
• Issued: 08/05/1997
• Est. Priority Date: 05/22/1996
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Hirst, Mark
• Primary Examiner(s): MOSES, RICHARD L
• Application Number:
  US08/651,309
• Time in Patent Office: 440 Days
• Field of Search: 399/27, 399/28, 399/29, 399/44, 399/224, 399/260, 347/19
• US Class Current: 399/27
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: G03G 15/0849 Detection or control means for the developer concentration
• CPC Class Codes: G03G 15/0856 Detection or control means for the developer level
• CPC Class Codes: G03G 15/556 for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement

Abstract

A system of the present invention includes an ambient condition sensor for estimating the consumption of toner, developer, or similar printing supply in an electrostatic or ink jet printer. In a preferred embodiment, the ambient condition being monitored is relative humidity, though in other embodiments other indicators of ambient air conductivity or break down voltage are measured. Consumption is estimated by classifying each pixel to be printed according to the number of neighbors of that pixel, accumulating a sum according to each classification, multiplying each accumulated sum by a weight that accounts for its classification, and calculating an overall sum of the weighted products. The overall sum is then scaled by a factor that accounts for the conductivity of ambient air as measured by the sensor to provide an incremental estimate of consumption. The scaling factor is determined by empirical studies. A warning such as "low toner" is displayed on the printing device and on a remote console when the integrated incremental estimates of consumption surpass a limit.

Claims

1. A system that estimates consumption of a printing supply, the system comprising:

a. an ambient condition sensor;

b. memory that stores a pixel description; and

c. a processor that provides a signal in response to estimating incremental consumption of the printing supply, wherein estimating is responsive to the sensor and to the pixel description.

2. The system of claim 1, wherein the sensor is responsive to a dielectric breakdown voltage of ambient air.

3. The system of claim 1, wherein the sensor is responsive to relative humidity of ambient air.

4. The system of claim 1, wherein:

a. the pixel description comprises a plurality of subpixel descriptions; and

b. the processor estimates incremental consumption of the supply in further response to a subpixel description of the plurality of subpixel descriptions.

5. The system of claim 4, wherein the processor:

a. determines a classification for the subpixel description in response to a neighboring subpixel description of the plurality of subpixel descriptions; and

b. estimates incremental consumption of the supply in further response to the classification.

6. The system of claim 5, wherein the processor accumulates for each classification a count of subpixels.

7. The system of claim 6, wherein the processor calculates an incremental estimate in response to a weighted sum of accumulated classification counts.

8. The system of claim 1, further comprising a monitor that advises managing of the supply, the monitor being responsive to the signal.

9. The system of claim 8 further comprising a network for coupling the monitor to the processor.

10. The system of claim 1, wherein:

a. the memory further stores a plurality of supply consumption factors, each factor corresponding respectively to a sensor signal value of a plurality of sensor signal values; and

b. the processor estimates incremental consumption of the supply in further response to a factor of the plurality of factors.

11. The system of claim 1, wherein a rate of consumption of the supply is adjusted in response to the signal.

12. The system of claim 1, wherein the supply comprises toner.

13. The system of claim 1, wherein the supply comprises ink.

14. A printer comprising:

a. first means for determining data that describes a plurality of pixels to be printed;

b. a humidity sensor that provides a sensor signal; and

c. second means for determining a low toner condition, the second means comprising a circuit that estimates toner consumption in response to the data and to the sensor signal.

15. The printer of claim 14, further comprising third means for providing a report at a location remote from the printer, the report responsive to the estimated toner consumption.

16. A method for sensing consumption of a printing supply, the method comprising:

a. receiving a first signal proportional to an ambient condition;

b. receiving a second signal that describes a plurality of pixels to be printed; and

c. providing a third signal in response to an estimate of consumption of the printing supply, wherein the estimate is responsive to the first signal and the second signal.

17. The method of claim 16, further comprising:

a. accumulating the estimate over a time; and

b. providing the third signal in response to comparing the accumulated estimate to a limit.

18. The method of claim 16, further comprising:

a. analyzing the second signal to determine a position of a pixel of the plurality of pixels;

b. associating a classification to the pixel in response to its position in a region;

c. accumulating a count of pixels of the plurality having the classification; and

d. estimating consumption of the supply in further response to the count.

19. The method of claim 16, further comprising:

a. analyzing the second signal to determine a representation of a pixel of the plurality of pixels, the representation comprising a plurality of subpixels;

b. determining a weight for a subpixel;

accumulating a count of subpixels having the same weight; and

c. estimating consumption of the supply in further response to the weight.

20. The method of claim 16, further comprising controlling dispensing of the supply in response to the third signal.