Cleaning mechanisms for build material level sensors

Patent metadata

Field	Value
Publication number	US-11660808-B2
Application number	US-201816607919-A
Country	US
Kind code	B2
Filing date	Jul 26, 2018
Priority date	Jul 26, 2018
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

In example implementations, a powder level sensor is provided. The powder level sensor includes a capacitive sensor, a processor, and a cleaning mechanism. The processor is communicatively coupled to the capacitive sensor. The processor interprets a measurement of the capacitive sensor to detect a layer of residual build material on a surface of the powder level sensor. The cleaning mechanism may be communicatively coupled to the processor. The processor activates the cleaning mechanism to remove the layer of residual build material on the surface of the powder level sensor.

First claim

The invention claimed is:

1. A build material level sensor, comprising:
a capacitive sensor;
a processor communicatively coupled to the capacitive sensor to interpret a measurement of the capacitive sensor to detect a layer of residual build material on a surface of the build material level sensor, wherein the layer of residual build material comprises build material that is stuck on the capacitive sensor in an otherwise empty build material dispenser; and
a cleaning mechanism communicatively coupled to the processor, wherein the processor activates the cleaning mechanism to remove the layer of residual build material on the surface of the build material level sensor.

2. The build material level sensor of claim 1 , wherein the measurement comprises an analog value of capacitance and the layer of residual build material on the surface of the build material level sensor is detected when the analog value is lower than a threshold value.

3. The build material level sensor of claim 1 , further comprising:
a temperature sensor communicatively coupled to the processor to measure a temperature of the surface of the build material level sensor; and
a heater communicatively coupled to the processor to heat the surface of the build material level sensor when the temperature falls below a temperature threshold value.

4. The build material level sensor of claim 3 , wherein the heater comprises a trace, wherein a current is applied to the trace by the processor based on the temperature that is measured to generate heat.

5. The build material level sensor of claim 1 , wherein the cleaning mechanism comprises:
an air pump to generate air; and
an air channel located adjacent to the surface of the build material level sensor to blow the air across the surface of the build material level sensor.

6. The build material level sensor of the claim 5 , wherein the cleaning mechanism further comprises:
a solenoid valve communicatively coupled to the processor, wherein the processor controls operation of the solenoid valve based on detection of the layer of residual build material on the surface of the build material level sensor.

7. The build material level sensor of claim 1 , further comprising:
a non-transitory machine-readable storage medium encoded with instructions executable by the processor, the machine-readable storage medium comprising:
instructions to heat the surface of the build material level sensor to a desired temperature;
instructions to measure an analog value of capacitance via the build material level sensor;
instructions to detect the layer of residual build material on the surface of the build material level sensor based on the analog value of capacitance; and
instructions to activate the cleaning mechanism to remove the layer of residual build material on the surface of the build material level sensor.

8. The build material level sensor of claim 1 , wherein the cleaning mechanism is located between a capacitive sensor plate and a ground plate.

9. The build material level sensor of claim 6 , wherein the solenoid valve is controlled to periodically open and close to create pulses of an air puff.

Assignees

• Hewlett Packard Development Co

Inventors

• Soriano David
• Pederson Douglas
• Baldo Nicola
• Ringwald Steve
• Sing Samrin
• Baker Matthew

Classifications

• G01F23/804

  containing circuits handling parameters other than liquid level · CPC title

• B33Y50/00

  Data acquisition or data processing for additive manufacturing · CPC title

• B22F12/50

  Means for feeding of material, e.g. heads · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title

• B22F10/14

  by jetting of binder onto a bed of metal powder · CPC title