Determining an issue in an inkjet nozzle with impedance measurements

Patent metadata

Field	Value
Publication number	US-9352564-B2
Application number	US-201214372715-A
Country	US
Kind code	B2
Filing date	Apr 19, 2012
Priority date	Apr 19, 2012
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A method for determining an issue in an inkjet nozzle with impedance measurements, includes taking a first impedance measurement to detect a drive bubble with an impedance sensor; and taking a second impedance measurement to detect said drive bubble with said impedance sensor after said first impedance measurement.

First claim

What is claimed is:

1. A method for determining an issue in an inkjet nozzle with impedance measurements, comprising:
taking a first impedance measurement to detect a presence of a drive bubble with an impedance sensor coupled to an interior surface of an ink chamber; and
taking a second impedance measurement to detect said drive bubble with said impedance sensor after said first impedance measurement.

2. The method of claim 1 , wherein taking a second impedance measurement to detect a drive bubble with said impedance sensor after said first impedance measurement includes taking said second impedance measurement two to seven microseconds after said first impedance measurement.

3. The method of claim 1 , further comprising determining said issue exists based on a combination of said first and second said impedance measurements.

4. The method of claim 3 , further comprising determining a type of said issue based on said first impedance measurement, second impedance measurement, or combinations thereof.

5. The method of claim 3 , further comprising initiating a remedial action in response to said issue with a processor in communication with said impedance sensor.

6. The method of claim 1 , wherein taking a first impedance measurement to detect a drive bubble with an impedance sensor includes taking said first impedance measurement after a drive bubble formation mechanism is activated.

7. The method of claim 1 , further comprising comparing said first and second measurements to firing commands to said ink chamber.

8. The method of claim 1 , wherein taking a first impedance measurement to detect a drive bubble with an impedance sensor includes taking multiple impedance readings at a first substantially same time and taking a second impedance measurement to detect said drive bubble with said impedance sensor includes taking said multiple impedance readings at a second substantially same time.

9. The method of claim 1 , further comprising:
determining an existence of said drive bubble when said first impedance measurement is above a first threshold impedance value; and
determining said existence of said drive bubble when said second impedance measurement is above a second impedance value that is different than said first impedance value.

10. The method of claim 1 , wherein taking a second impedance measurement to detect a drive bubble with said impedance sensor after said first impedance measurement includes taking the first and second measurements during a printing job, during a servicing event, or combinations thereof.

11. An ink jet print head, comprising:
an ink chamber comprising a drive bubble formation mechanism and an impedance sensor positioned on an interior surface of the ink chamber, the impedance sensor to detect a presence of a drive bubble as the drive bubble is created and contacts the impedance sensor;
said impedance sensor being in communication with a processor programmed to:
take a first impedance measurement within said ink chamber after initiating a drive bubble formation mechanism.

12. The print head of claim 11 , wherein said processor is further programmed to send a firing command to a drive bubble formation mechanism in said ink chamber before taking said first measurement.

13. The inkjet print head of claim 11 , wherein the processor is further programmed:
to take a second impedance measurement within said ink chamber after taking said first measurement; and
to determine an issue in the ink chamber based on the first and second impedance measurements.

14. The inkjet print head of claim 13 , wherein the processor is further programmed to take a remedial action in response to determining the issue.

15. The ink jet print head of claim 14 , the processor further comprising a table specifying a remedial action to take based on both the first and second impedance measurements.

16. The ink jet print head of claim 11 , further comprising a sensing multiplexer to provide output from impedance sensors in a plurality of ink chambers.

17. The ink jet print head of claim 11 , further comprising:
first and second time results repositories for storing, respectively, impedance measurements taken a first time after initiation of a bubble formation mechanism, and impedance measurements taken a second, subsequent time after initiation of a bubble formation mechanism; and
a nozzle health repository for storing information about a health of a nozzle corresponding to said ink chamber.

18. A printer, comprising:
a nozzle in fluid communication with an ink chamber, said ink chamber comprising a impedance sensor to detect a presence of a drive bubble within the ink chamber; and
said impedance sensor being in communication with a processor, said processor programmed to:
send a first measurement command to said impedance sensor;
send a second measurement command to said impedance sensor after said first measurement command; and
determine an issue within said ink chamber based on measurements taken in response to said first and second measurement commands.

19. The printer of claim 18 , wherein said processor is further programmed to send a firing command to a drive bubble formation mechanism in said ink chamber before sending said first measurement command.

20. The printer of claim 18 , wherein said processor is further programmed to distinguish between issues from a group consisting of weak bubble formations, blocked chamber outlets, and stray bubbles.

Assignees

• Van Brocklin Andrew L
• Martin Eric T
• Govyadinov Alexander
• Maxfield David
• Hewlett Packard Development Co

Inventors

• Van Brocklin Andrew L
• Martin Eric T
• Govyadinov Alexander
• Maxfield David

Classifications

• B41J29/393

  Devices for controlling or analysing the entire machine {; Controlling or analysing mechanical parameters involving printing of test patterns} · CPC title

• B41J2/0458

  controlling heads based on heating elements forming bubbles · CPC title

• B41J2/0451

  for detecting failure, e.g. clogging, malfunctioning actuator · CPC title

• B41J2002/14354

  Sensor in each pressure chamber · CPC title

• B41J2/14153 Primary

  Structures including a sensor · CPC title