Inkjet printing apparatus and detection method

Patent metadata

Field	Value
Publication number	US-9097591-B2
Application number	US-201414224496-A
Country	US
Kind code	B2
Filing date	Mar 25, 2014
Priority date	Mar 27, 2013
Publication date	Aug 4, 2015
Grant date	Aug 4, 2015

Abstract

An inkjet printing apparatus includes a current source configured to be able to supply, to a resistance sensor, a constant current of the first constant current value and a constant current of the second constant current value larger than the first constant current value. A change of the resistance value of the resistance sensor is detected by switching the value of the constant current to be supplied to the resistance sensor between the first constant current value and the second constant current value a predetermined time after driving a heater to discharge an ink droplet.

First claim

What is claimed is:

1. An inkjet printing apparatus comprising:
a printhead including a heater configured to discharge an ink droplet from a nozzle, and a resistance sensor whose resistance value changes upon a temperature change of the heater;
a current source configured to be able to supply, to the resistance sensor, a constant current of a first constant current value and a constant current of a second constant current value larger than the first constant current value; and
a detection unit configured to detect a change of the resistance value of the resistance sensor by switching a value of the constant current to be supplied to the resistance sensor between the first constant current value and the second constant current value a predetermined time after driving the heater to discharge the ink droplet.

2. The apparatus according to claim 1 , further comprising a determination unit configured to determine a discharge state of the ink droplet of the nozzle based on the change of the resistance value of the resistance sensor that has been detected by said detection unit.

3. The apparatus according to claim 2 , wherein said determination unit determines the discharge state of the ink droplet of the nozzle based on a change of the resistance value of the resistance sensor to which the constant current of the second constant current value is supplied.

4. The apparatus according to claim 1 , wherein a period during which the constant current of the second constant current value is supplied corresponds to a period during which a temperature of the heater drops to a predetermined temperature after reaching a peak.

5. An inkjet printing apparatus including a printhead including a heater configured to discharge an ink droplet from a nozzle, and a sensor whose output voltage changes upon a temperature change of the heater, comprising:
a current source configured to be able to supply, to the sensor, a constant current of a first constant current value and a constant current of a second constant current value larger than the first constant current value; and
a detection unit configured to detect a change of the output voltage of the sensor by switching a value of the constant current to be supplied to the sensor between the first constant current value and the second constant current value a predetermined time after driving the heater to discharge the ink droplet.

6. The apparatus according to claim 5 , further comprising a determination unit configured to determine a discharge state of the ink droplet of the nozzle based on the change of the output voltage of the sensor that has been detected by said detection unit.

7. The apparatus according to claim 6 , wherein said determination unit determines the discharge state of the ink droplet of the nozzle based on a change of the output voltage of the sensor to which the constant current of the second constant current value is supplied.

8. The apparatus according to claim 5 , wherein a period during which the constant current of the second constant current value is supplied corresponds to a period during which a temperature of the heater drops to a predetermined temperature after reaching a peak.

Assignees

• Canon Kk

Inventors

• Ike Takeshi

Classifications

• B41J2/16579

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

• B41J2/04563

  detecting head temperature; Ink temperature · CPC title

• B41J2/05

  produced by the application of heat · CPC title

• G01K7/16 Primary

  using resistive elements · CPC title

• B41J2/0451 Primary

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