Modules to identify nozzle chamber operation

Patent metadata

Field	Value
Publication number	US-9931837-B2
Application number	US-201415307865-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Jun 30, 2014
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

An example device in accordance with an aspect of the present disclosure includes modules to communicate an input signal to an ink sample to obtain an ink signal, compare the ink signal to a reference value, and identify an indicator of nozzle chamber operation corresponding to the ink signal. A module may be contained on an inkjet printhead die, such that the device may generate the input signal on the inkjet printhead die.

First claim

What is claimed is:

1. A device comprising:
a signal source to communicate an input signal to an ink sample associated with a nozzle to be fired, to obtain, during an evaluation interval, an ink signal including an impedance characteristic;
a comparator to compare the ink signal to a reference value; and
a counter to count over the evaluation interval in response to the comparing indicating that an evaluation criterion is satisfied, and the counter to stop counting in response to the comparing indicating that the evaluation criterion is not satisfied, a count value of the counter providing an indicator of nozzle chamber operation corresponding to the ink signal;
wherein the signal source is contained on an inkjet printhead die, such that the device may generate the input signal on the inkjet printhead die.

2. The device of claim 1 , wherein the comparator and the counter are also contained on the inkjet printhead die, such that the device may evaluate the indicator without the ink signal leaving the inkjet printhead die.

3. The device of claim 1 , further comprising switches to selectively couple the signal source to the ink sample, and couple the ink signal to the comparator.

4. The device of claim 1 , further comprising:
a storage to store the reference value; and
a controller to iteratively update the reference value in successive iterations,
wherein the comparator is to compare ink signals in the successive iterations to respective updated reference values.

5. The device of claim 4 , wherein the storage includes a programmable memory on the inkjet printhead die.

6. The device of claim 1 , wherein the counter is to start counting in response to a fire pulse.

7. The device of claim 6 , wherein once the counter starts counting in response to the fire pulse, the counter is to continue to count in response to the comparing indicating that an evaluation criterion is satisfied.

8. The device of claim 6 , wherein the fire pulse is to activate the nozzle.

9. The device of claim 1 , wherein the count value of the counter identifies a duration between activation of the nozzle and a time at which the comparing indicates that the evaluation criterion is not satisfied.

10. The device of claim 9 , further comprising a register to store the count value of the counter.

11. The device of claim 1 , wherein the evaluation criterion is satisfied if the ink signal is greater than the reference value, and the evaluation criterion is not satisfied if the ink signal is below the reference value.

12. The device of claim 1 , wherein the counter is to count clock cycles of a clock signal while the comparing indicates that the evaluation criterion is satisfied.

13. The device of claim 12 , further comprising a gate to:
enable the clock signal to be transmitted to a clock port of the counter while the comparing indicates that the evaluation criterion is satisfied,
block the clock signal from the clock port of the counter if the comparing indicates that the evaluation criterion is not satisfied.

14. A device comprising:
a signal module comprising a signal source, a first switch, and a second switch, the first switch when activated to communicate an input signal to an ink sample associated with a nozzle to be fired, to obtain, during an evaluation interval, an ink signal including an impedance characteristic;
a comparator, wherein the second switch when activated is to couple the ink signal to an input of the comparator, the comparator to compare the ink signal to a reference value; and
a counter to count over the evaluation interval in response to the comparing indicating that an evaluation criterion is satisfied, and the counter to stop counting in response to the comparing indicating that the evaluation criterion is not satisfied, a count value of the counter identifies a duration of the evaluation interval and provides an indicator of nozzle chamber operation corresponding to the ink signal;
wherein the signal module is contained on an inkjet printhead die, such that the device may generate the input signal on the inkjet printhead die.

15. The device of claim 14 , further comprising a register to store the count value of the counter independent of whether the counter is reset.

16. The device of claim 14 , wherein the counter is to start counting in response to a fire pulse that activates the nozzle, the counter to continue to count in response to the comparing indicating that an evaluation criterion is satisfied.

17. The device of claim 14 , wherein the counter is to count clock cycles of a clock signal while the comparing indicates that the evaluation criterion is satisfied, the device further comprising a gate to:
enable the clock signal to be transmitted to a clock port of the counter while the comparing indicates that the evaluation criterion is satisfied,
block the clock signal from the clock port of the counter if the comparing indicates that the evaluation criterion is not satisfied.

18. A method comprising:
communicating an input signal from a signal source to an ink sample associated with a nozzle to be fired;
receiving, during an evaluation interval, an ink signal including an impedance characteristic, the ink signal responsive to the input signal communicated to the ink sample;
comparing, by a comparator, the ink signal to a reference value;
counting, by a counter over the evaluation interval, while the comparing indicates that an evaluation criterion is satisfied;
stopping the counter in response to the comparing indicating that the evaluation criterion is not satisfied; and
outputting a count value of the counter, the count value providing an indicator of nozzle chamber operation corresponding to the ink signal.

19. The method of claim 18 , further comprising initializing the reference value by a printer, in response to printer startup.

20. The method of claim 18 , further comprising:
enabling, by a gate, transmission of the clock signal to a clock port of the counter while the comparing indicates that the evaluation criterion is satisfied,
blocking, by the gate, the clock signal from the clock port of the counter if the comparing indicates that the evaluation criterion is not satisfied.

Assignees

• Hewlett Packard Development Co
• Hewlett Packard Development Lp

Inventors

• Anderson Daryl E
• Martin Eric T
• Fricke Peter James
• Gardner James Michael

Classifications

• B41J2/04541

  Specific driving circuit · CPC title

• B41J2/16579

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

• B41J2/14153

  Structures including a sensor · CPC title

• B41J2/0458

  controlling heads based on heating elements forming bubbles · CPC title

• B41J2/0451 Primary

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