Fluidic die with surface condition monitoring

Patent metadata

Field	Value
Publication number	US-11559987-B2
Application number	US-201917058690-A
Country	US
Kind code	B2
Filing date	Jan 31, 2019
Priority date	Jan 31, 2019
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

One example provides a fluidic die including a nozzle layer disposed on a substrate, the nozzle layer having an upper surface opposite the substrate and including a plurality of nozzles formed therein, each nozzle including a fluid chamber and a nozzle orifice extending through the nozzle layer from the upper surface to the fluid chamber. A conductive trace is exposed to the upper surface of the nozzle layer and extends proximate to a portion of the nozzle orifices, an impedance of the conductive trace indicative of a surface condition of the upper surface of the nozzle layer.

First claim

The invention claimed is:

1. A fluidic die comprising:
a substrate;
a nozzle layer disposed on the substrate, the nozzle layer having an upper surface opposite the substrate and including a plurality of nozzles formed therein, each nozzle including a fluid chamber and a nozzle orifice extending through the nozzle layer from the upper surface to the fluid chamber;
a conductive trace exposed to the upper surface of the nozzle layer and extending proximate to and spaced from a portion of the nozzle orifices; and
control logic to monitor impedance of the conductive trace, and to compare the monitored impedance to known expected impedance values to determine a temperature and a presence of fluid at the upper surface of the nozzle layer.

2. The fluidic die of claim 1 , the conductive trace extending along opposite sides of the portion of nozzle orifices.

3. The fluidic die of claim 1 , the portion of nozzle orifices comprising a column of nozzles.

4. The fluidic die of claim 1 , the conductive trace embedded within the nozzle layer with a portion exposed to the upper surface.

5. The fluidic die of claim 1 , the conductive trace disposed on the upper surface of the nozzle layer.

6. The fluidic die of claim 1 , an impedance of the conductive trace indicating a presence of a fluid puddle on the upper surface which is simultaneously in contact with the conductive trace on each side of a column of nozzle orifices.

7. The fluidic die of claim 1 , the conductive trace having a temperature-dependent resistance indicative of the temperature of the upper surface of the nozzle layer.

8. The fluidic die of claim 1 , the impedance of the conductive trace in a first range indicating a temperature of the upper surface and in a second range indicating a presence of fluid on the upper surface.

9. The fluidic die of claim 1 , the conductive trace including:
a first segment and a second segment extending on opposite sides of the portion of nozzle orifices; and
a third segment extending laterally to and joining the first and second segments to form a continuous conductive trace.

10. The fluidic die of claim 9 , the third segment having a length selected to increase a signal-to-noise ratio of an electrical property of the conductive trace.

11. A printhead comprising:
a fluidic die including:
a substrate;
a nozzle layer disposed on the substrate and having an upper surface opposite the substrate, the nozzle layer including a plurality of nozzles formed therein, each nozzle including a fluid chamber and a nozzle orifice extending through the nozzle layer from the upper surface to the fluid chamber; and
a conductive trace exposed to the upper surface of the nozzle layer and extending proximate to and spaced from a portion of the nozzle orifices; and
a monitoring circuit to monitor an impedance of the conductive trace, and to compare the monitored impedance to known expected impedance values to determine a temperature and a presence of fluid at the upper surface of the nozzle layer.

12. A method of monitoring a fluidic die including:
disposing a conductive trace exposed to an upper surface of a nozzle layer of a fluidic die, the conductive trace extending proximate to and spaced from a group of nozzle orifices of a plurality of nozzles formed in the nozzle layer;
monitoring an impedance of the conductive trace; and
comparing the monitored impedance to known expected impedance values to determine a temperature and a presence of fluid at the upper surface of the nozzle layer.

13. The method of claim 12 , wherein known expected impedance values in a first range are indicative of the temperature, and known expected impedance values in a second range are indicative of the presence of fluid.

Assignees

• Hewlett Packard Development Co

Inventors

• Martin Eric
• Anderson Daryl E
• Przybyla James R
• Chen Chien-Hua
• Hammerstad Diane R

Classifications

• B41J2/1433

  Structure of nozzle plates · CPC title

• B41J2/04581

  controlling heads based on piezoelectric elements · CPC title

• B41J2/14201

  Structure of print heads with piezoelectric elements · CPC title

• B41J2/04563 Primary

  detecting head temperature; Ink temperature · CPC title

• B41J2/14016

  Structure of bubble jet print heads · CPC title