Abstract: An embodiment of this invention is directed to determining a discharge status of liquid discharged from a liquid discharge head capable of accurately determining the discharge status of each nozzle at high speed with a simple arrangement. According to the embodiment, a base includes an electrothermal transducer configured to supply heat to liquid, a first temperature detection element configured to detect the temperature of the electrothermal transducer, and a second temperature detection element configured to detect the temperature of the same electrothermal transducer. In this case, the first and the second temperature detection elements are arranged so that at least part of each of the first and second temperature detection elements is included immediately above or below a region where the electrothermal transducer is arranged in the base.

Abstract: An embodiment of this invention is directed to determining a discharge status of liquid discharged from a liquid discharge head capable of accurately determining the discharge status of each nozzle at high speed with a simple arrangement. According to the embodiment, a base includes an electrothermal transducer configured to supply heat to liquid, a first temperature detection element configured to detect the temperature of the electrothermal transducer, and a second temperature detection element configured to detect the temperature of the same electrothermal transducer. In this case, the first and the second temperature detection elements are arranged so that at least part of each of the first and second temperature detection elements is included immediately above or below a region where the electrothermal transducer is arranged in the base.

Abstract: An embodiment of this invention is directed to determination of the ink discharge state of a printhead capable of accurately determining the discharge state of each nozzle while suppressing increases in the size and cost of an apparatus. In the embodiment, the ink discharge state of a printing apparatus including a printhead including a heater for discharging ink and a temperature sensor, and a driving unit configured to drive the heater is determined as follows. It is controlled to drive the heater by applying the first voltage for discharging ink, and drive the heater by applying the second voltage enough not to discharge the ink. Whether ink is normally discharged or discharge failure has occurred is determined based on information obtained from detected plural temperatures in regard to the application timing of the second voltage.

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.

Abstract: An embodiment of this invention is directed to determination of the ink discharge state of a printhead capable of accurately determining the discharge state of each nozzle while suppressing increases in the size and cost of an apparatus. In the embodiment, the ink discharge state of a printing apparatus including a printhead including a heater for discharging ink and a temperature sensor, and a driving unit configured to drive the heater is determined as follows. It is controlled to drive the heater by applying the first voltage for discharging ink, and drive the heater by applying the second voltage enough not to discharge the ink. Whether ink is normally discharged or discharge failure has occurred is determined based on information obtained from detected plural temperatures in regard to the application timing of the second voltage.

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.

Abstract: This invention has been made to judge the discharge state of each nozzle accurately at an appropriate timing. For this purpose, an apparatus using a printhead including a heater and a temperature sensor has the following arrangement. A temporal change in a detected temperature is monitored upon driving the printhead. During the temperature drop, temperatures are extracted at plural points of a time interval including a timing at which a feature point of the temporal change in the detected temperature in normal discharge appears. The second derivative of the temperature is calculated and added to obtain a total sum and intermediate sum. The total sum is compared with predetermined first and second thresholds to judge whether to normally discharge ink. If normal discharge or discharge failure is uncertain, the intermediate sum is compared with a third threshold for final judgment.

Abstract: The present invention has been made to judge the discharge state of each nozzle accurately at an appropriate timing. For this purpose, a printing apparatus using a printhead including a heater and a temperature sensor to detect a temperature of the heater has the following arrangement. A temporal change in a detected temperature is monitored upon driving the printhead. In the temperature dropping process, temperatures are extracted at plural points of a time interval including a timing at which a feature point of the temporal change in the detected temperature in normal discharge appears. The second derivative of the temperature is calculated and added to obtain a total sum. The total sum is compared with a threshold defined based on the characteristic of the temporal change in the monitored temperature in discharge failure, thereby judging whether to normally discharge ink.