Printing apparatus and methods for detecting fluid levels

Patent metadata

Field	Value
Publication number	US-10926548-B2
Application number	US-201616094138-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Apr 29, 2016
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

An example printing cartridge includes a fluid container, a plurality of capacitor plates to detect fluid in the fluid container, each of the capacitor plates associated with a respective fluid level, and a shift register to capture fluid level information from the plurality of capacitor plates.

First claim

We claim:

1. A printing cartridge comprising:
a fluid container defining a volume;
a plurality of capacitor plates to detect fluid in the fluid container, respective ones of the capacitor plates associated with a respective fluid level;
an oscillator to generate a clock signal;
a shift register to, in response to the clock signal, capture fluid level information based on outputs from the plurality of capacitor plates, the shift register including a plurality of flip-flops in circuit with the plurality of capacitor plates, at least one of the flip-flops to store the fluid level information;
a voltage supply line to shift the fluid level information out of the printing cartridge, where the voltage supply line is to be pulled down a first percentage to transmit a first value from the shift register and the voltage supply line is to be pulled down a second percentage to transmit a second value from the shift register, the second percentage different than the first percentage, the second value different than the first value; and
an electrical interface to map the fluid level information to a percentage of the volume.

2. The printing cartridge of claim 1 , wherein the flip-flops are to store respective fluid level values when a voltage is provided to the shift register.

3. The printing cartridge of claim 1 , wherein a first one of the flip-flops is to store a first fluid level value when a corresponding capacitor plate detects presence of the fluid in the fluid container, and the first sensing flip-flop is to store a second fluid level value when the corresponding capacitor plate does not detect presence of the fluid in the fluid container.

4. The printing cartridge of claim 1 , wherein the electrical interface is to map a logical high value from the shift register to the percentage of the volume.

5. The printing cartridge of claim 4 , wherein the electrical interface is to:
generate a signal based on the output of the shift register; and
transmit the signal to a printer.

6. The printing cartridge of claim 1 , wherein the plurality of capacitor plates are to detect a presence of fluid in the fluid container without being in physical contact with fluid.

7. A sensing die comprising:
a plurality of capacitor plates; and
a serial-in and serial-out register including a plurality of sensing flip-flops to:
monitor fluid in a fluid container via a respective capacitor plate of the plurality of capacitor plates, respective ones of the sensing flip-flops associated with a respective fluid level,
store a respective fluid level value based on a presence of fluid detected by the corresponding capacitor plate,
store the respective fluid level values in response to a voltage applied to the sensing die,
store a first fluid level value when fluid is detected by the corresponding capacitor plate and store a second fluid level value when fluid is not detected by the corresponding capacitor plate,
change a voltage on a voltage supply line a first percentage to transmit a first value corresponding to the first fluid level value, and
change the voltage on the voltage supply line a second percentage to transmit a second value corresponding to the second fluid level value, the second percentage different than the first percentage, the second value different than the first value.

8. A printing cartridge comprising:
a fluid container;
a capacitor plate positioned relative to the fluid container to detect a presence of fluid in the fluid container at a fluid level;
a sensing flip-flop in circuit with the capacitor plate, the sensing flip-flop including a latch to store fluid information representative of fluid detected by the capacitor plate at the fluid level; and
a voltage supply line to shift the fluid level information out of the printing cartridge, where the voltage supply line is to be changed a first percentage to transmit a first value from the sensing flip-flop and the voltage supply line is to be changed a second percentage to transmit a second value from the sensing flip-flop, the second percentage different than the first percentage, the second value different than the first value.

9. The apparatus of claim 8 , wherein the sensing flip-slop is one of a plurality of sensing flip-flops, the plurality of sensing flip-flops to implement a shift register to capture the fluid level information of the fluid container.

10. The apparatus of claim 9 , wherein the shift register is a serial-in and serial-out register.

11. The apparatus of claim 9 , wherein the plurality of sensing flip-flops are to latch respective values representative of fluid detected in response to a voltage applied to the shift register.

12. The apparatus of claim 8 , wherein the latch includes:
an input latch in circuit with the capacitor plate, the input latch including:
a first gate,
a first inverter, and
a second inverter; and

an output latch including:
a second gate,
a third inverter, and
a fourth inverter,

wherein the input latch is in circuit with the output latch via a fifth inverter.

13. The apparatus of claim 12 , wherein the first gate is a first tristate driver and the second gate is a second tristate driver.

Assignees

• Hewlett Packard Development Co

Inventors

• Anderson Daryl E
• Gardner James Michael
• Linn Scott A
• Cumbie Michael W
• Fisher Berkeley

Classifications

• B41J2002/17579

  Measuring electrical impedance for ink level indication · CPC title

• G01F23/265

  for discrete levels · CPC title

• B41J2/17566 Primary

  Ink level or ink residue control · CPC title

• B41J2/17546

  electronically · CPC title

• G01F23/266

  measuring circuits therefor · CPC title