On-die actuator failure detection

Patent metadata

Field	Value
Publication number	US-10800166-B2
Application number	US-201716483497-A
Country	US
Kind code	B2
Filing date	Apr 5, 2017
Priority date	Apr 5, 2017
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

In one example in accordance with the present disclosure, a fluid ejection die is described. The die includes a number of actuator sensors disposed on the fluid ejection die to sense a characteristic of a corresponding actuator and to alter an evaluation voltage based on a performance of the corresponding actuator. The die also includes an actuator evaluation device per primitive to detect a failed actuator based at least in part on a comparison of the altered evaluation voltage and at least one threshold voltage. The die also includes a number of disable device coupled to respective actuators and to disable failed actuators.

First claim

What is claimed is:

1. A fluid ejection die comprising:
a number of actuator sensors disposed on the fluid ejection die to:
sense a characteristic of a corresponding actuator; and
alter an evaluation voltage based on a performance of the corresponding actuator,

an actuator evaluation device per primitive to detect a failed actuator based at least in part on a comparison of the altered evaluation voltage and at least one threshold voltage; and
a number of disable devices, wherein each disable device:
is coupled to a respective actuator; and
is to disable a failed actuator.

2. The fluid ejection die of claim 1 , wherein the actuator evaluation device:
comprises a first comparator to determine when the altered evaluation voltage is greater than a high threshold voltage;
comprises a second comparator to determine when the altered evaluation is less than a low threshold voltage; and
detects a failed actuator when the altered evaluation is at least one of:
greater than the high threshold voltage; and
less than the low threshold voltage.

3. The fluid ejection die of claim 2 , further comprising a maintain device to maintain the evaluation voltage between the high threshold voltage and the low threshold voltage absent a detected failure.

4. The fluid ejection die of claim 1 , wherein the disable device comprises a buffer device for conditioning an activation pulse directed to the corresponding actuator.

5. The fluid ejection die of claim 1 , wherein the disable device comprises a latch to selectively store an output of the actuator evaluation device.

6. The fluid ejection die of claim 5 , further comprising a delay device to delay the storing of the output of the actuator evaluation device at the latch relative to an initial activation pulse.

7. The fluid ejection die of claim 5 , wherein the disable device comprises a gate coupled to the latch to:
disable the corresponding actuator when an output of the latch indicates a failed actuator;
enable the actuator when an output of the latch indicates a functioning actuator, the actuator is selected, and the actuator has received an activation pulse.

8. The fluid ejection die of claim 5 , wherein an activation pulse for activating an actuator selectively activates the latch to store the output of the activation evaluation device.

9. The fluid ejection die of claim 1 , wherein the disable device is a one-time write memory device to permanently disable the corresponding actuator upon a detection that the corresponding actuator has failed.

10. A fluid ejection system comprising:
multiple fluid ejection dies, wherein a fluid ejection die comprises:
a number of actuator sensors to:
sense a characteristic of a corresponding actuator; and
alter an evaluation voltage based on a detected short between the actuator sensor and the corresponding actuator, wherein:
each actuator sensor is coupled to a respective actuator; and
multiple coupled actuator sensors and actuators are grouped as primitives on the fluid ejection die;

an actuator evaluation device per primitive to indicate a short between the actuator sensor and an actuator based at least in part on a comparison of the altered evaluation voltage and at least one threshold voltage; and
a number of disable devices, wherein each disable device:
is coupled to a respective actuator; and
is to disable a corresponding actuator when a short between the actuator sensor and the actuator is detected.

11. The fluid ejection system of claim 10 , wherein:
each actuator sensor is uniquely paired with an actuator;
each disable device is uniquely paired with an actuator; and
a single actuator evaluation device is shared among all the actuators in the primitive.

12. The fluid ejection system of claim 10 , wherein the number of disable devices are resettable disable devices.

13. A method comprising:
receiving an activation pulse for activating an actuator of a primitive on a fluid ejection die;
activating the actuator based on the activation pulse;
altering an evaluation voltage via an actuator sensor, based on a performance of a corresponding actuator, which evaluation voltage is altered responsive to the activation of the corresponding actuator;
detecting a failure of the corresponding actuator based at least in part on a comparison of the altered evaluation voltage against at least one threshold; and
disabling the corresponding actuator when a comparison indicates the corresponding actuator has failed.

14. The method of claim 13 , further comprising delaying the disabling of the corresponding actuator a predetermined period of time following the activation of the corresponding actuator based on a time-delayed signal.

15. The method of claim 14 , further comprising selectively allowing the activation pulse to selectively activate a latch to store an output of the actuator evaluation device.

Assignees

• Hewlett Packard Development Co
• Hewlett Packard Dev Comany L P

Inventors

• Gardner James Michael
• Anderson Daryl E
• Martin Eric

Classifications

• B41J2002/14354

  Sensor in each pressure chamber · CPC title

• B41J2/2142

  Detection of malfunctioning nozzles (generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045, B41J2/05; jet deflection sensors B41J2/125; for cleaning purposes B41J2/16579) · CPC title

• B41J2/165

  Prevention {or detection} of nozzle clogging, e.g. cleaning, capping or moistening for nozzles · CPC title

• B29C64/112

  using individual droplets, e.g. from jetting heads · CPC title

• B41J2/16579

  Detection means therefor, e.g. for nozzle clogging · CPC title