Printhead condition detection system

Patent metadata

Field	Value
Publication number	US-9493002-B2
Application number	US-201514683699-A
Country	US
Kind code	B2
Filing date	Apr 10, 2015
Priority date	Apr 10, 2015
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A fluid printhead including at least one fluid ejection element. The fluid ejection element includes a fluid chamber, a throat portion through which fluid is provided to the fluid chamber, and a heater element disposed within the fluid chamber. The fluid ejection element also includes a printhead condition detection system. The printhead condition detection system includes a first electrode at least a portion of which is disposed within the fluid chamber, the first electrode configured to receive a step voltage, a second electrode disposed within the throat portion, and a sense circuit electrically connected to the second electrode that generates an output based on the application of the step voltage to the first electrode as an indication of printhead condition.

First claim

What is claimed is:

1. A fluid printhead, comprising:
a plurality of fluid ejection elements, each fluid ejection element comprising:
a fluid chamber;
a throat portion through which fluid is provided to the fluid chamber; and
a heater element disposed within the fluid chamber; and

a printhead condition detection element comprising:
a common first electrode formed by a cavitation layer that is common to each fluid chamber, the common first electrode receives a step voltage;
a plurality of second electrodes, each second electrode disposed within a respective throat portion; and
a plurality of sense circuits electrically connected to each second electrode that generates an output based on the application of the step voltage to the common first electrode as an indication of printhead condition.

2. The fluid printhead of claim 1 , further comprising a stimulus node that receives the step voltage for delivery to the common first electrode.

3. The fluid printhead of claim 1 , further comprising a sense bus that receives the output from the plurality of sense circuits.

4. The fluid printhead of claim 1 , wherein the output of each sense circuit is a digital high output upon a condition that fluid is present in each respective fluid chamber.

5. The fluid printhead of claim 1 , wherein the output of each sense circuit is a digital low output upon a condition that fluid is not present in each respective fluid chamber.

6. A fluid printer comprising:
a housing; and
one or more printhead assemblies movably connected to the housing so that the one or more printhead assemblies eject fluid onto a print medium as the one or more printheads move relative to the housing in accordance with a control mechanism, wherein at least one of the one or more printhead assemblies comprises:
a fluid printhead, comprising:
a plurality of fluid ejection elements, each fluid ejection element comprising:
a fluid chamber;
a throat portion through which fluid is provided to the fluid chamber; and
a heater element disposed within the fluid chamber; and

a printhead condition detection element comprising:
a common first electrode formed by a cavitation layer that is common to fluid chamber, the common first electrode configured to receive a step voltage;
a plurality of second electrodes, each second electrode disposed within a respective throat portion; and
a plurality of sense circuits electrically connected to each second electrode that generates an output based on the application of the step voltage to the common first electrode as an indication of printhead condition.

7. The fluid printer of claim 6 , further comprising a stimulus node configured to receive the step voltage for delivery to the common first electrode.

8. The fluid printer of claim 6 , further comprising a sense bus that receives the output from the plurality of sense circuits.

9. The fluid printer of claim 6 , wherein the output of each sense circuit is a digital high output upon a condition that fluid is present in each respective fluid chamber.

10. The fluid printer of claim 6 , wherein the output of each sense circuit is a digital low output upon a condition that fluid is not present in each respective fluid chamber.

Assignees

• Funai Electric Co

Inventors

• Edelen John Glenn
• Bergstedt Steve

Classifications

• B41J2/14072

  Electrical connections, e.g. details on electrodes, connecting the chip to the outside... · CPC title

• B41J2/04541 Primary

  Specific driving circuit · CPC title

• B41J2/04573

  Timing; Delays · CPC title

• B41J2002/14354

  Sensor in each pressure chamber · CPC title

• B41J2002/14491

  Electrical connection · CPC title