Printhead and printing apparatus using the same

• US 5,886,713 A
• Filed: 03/14/1996
• Issued: 03/23/1999
• Est. Priority Date: 03/17/1995
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Imanaka, Yoshiyuki, Okada, Masaaki, Kamiyama, Yuji
• Primary Examiner(s): Nguyen, Matthew
• Application Number:
  US08/615,822
• Time in Patent Office: 1,104 Days
• Field of Search: 347/6, 347/7, 347/10, 347/14, 347/19, 347/26, 347/37, 347/54, 347/56, 347/57
• US Class Current: 347/14
• CPC Class Codes: B41J 2/0451 for detecting failure, e.g. clogging, malfunctioning actuator
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/0458 controlling heads based on heating elements forming bubbles
• CPC Class Codes: B41J 2/14153 Structures including a sensor
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: B41J 2202/13 Heads having an integrated circuit
• CPC Class Codes: B41J 29/393 Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns

Abstract

A printhead capable of informing a printer of existence or absence of ink so as to prevent an ink discharge failure without increasing manufacturing cost and causing increase in size, and a printer using the printhead capable of performing printing operation at high speed without any heavy processing load and causing increase in size are disclosed. This printhead comprises an ink sensor or a thermosensor including a circuit for processing an output signal from the sensor, and outputs a processed result of the output signal from the sensor to a control circuit of the printing apparatus. The control circuit of the printing apparatus controls so as to terminate a printing operation in accordance with a signal level of the inputted signal, and to start an ink suction recovery operation.

Claims

1. A printhead for printing on a recording medium by applying an electric current pulse to an electrothermal transducer so as to generate heat, and discharging an ink droplet from a nozzle by utilizing the generated heat, said printhead comprising:

a driving circuit driving the electrothermal transducer;

a sensor circuit sensing a status of said printhead, and outputting a signal according to the sensed status;

a processing circuit determining existence or absence of ink in the nozzle, based on the signal outputted from said sensor circuit; and

an output terminal outputting a result obtained by said processing circuit to outside as a determination result, wherein said sensor circuit, said processing circuit, and said output terminal are packaged together with said driving circuit in a substrate provided in said printhead.

2. The printhead according to claim 1, wherein said sensor circuit includes a thermosensor for measuring temperature inside of said printhead, and the signal outputted from said sensor circuit depends on the temperature.

3. The printhead according to claim 2, wherein said processing circuit comprises a comparator for comparing an output signal from said thermosensor and a predetermined output signal corresponding to threshold temperature set in said processing circuit, and said comparator outputs a signal whose output level differs in dependence upon a comparison result from said output terminal.

4. The printhead according to claim 2, wherein said thermosensor is made of a diode, aluminum, polysilicon, or the like, which changes resistance in a large rate in response to temperature.

5. The printhead according to claim 4, wherein said thermosensor is formed in a semi-conductor manufacturing process along with said processing circuit and said driving circuit.

6. The printhead according to claim 1, wherein said sensor circuit includes a sensor for measuring electrical resistance inside of the nozzle, and the signal outputted from said sensor circuit depends on the electrical resistance.

7. The printhead according to claim 6, wherein said output terminal outputs a signal of an output level which differs in accordance with a measured result of the electrical resistance.

8. The printhead according to claim 7, wherein a number of output levels of the output signal from said output terminal is two, and the output levels are a high level and a low level.

9. The printhead according to claim 6, wherein an upper surface of the substrate is covered with a passivation film, and the sensor for measuring electrical resistance is formed in a part of the passivation film.

10. The printhead according to claim 9, wherein the part of the passivation film where the sensor is formed is a tantalum film.

11. The printhead according to claim 10, wherein the sensor for measuring electrical resistance is formed by patterning the tantalum film in a semi-conductor manufacturing process.

12. The printhead according to claim 9, wherein a plurality of the sensors for measuring electrical resistance are formed.

13. The printhead according to claim 1, wherein said sensor circuit comprises a thermosensor for measuring temperature inside of said printhead and a circuit for measuring electrical resistance inside of the nozzle.

14. The printhead according to claim 13, wherein said processing circuit comprises a comparator for comparing an output signal from the thermosensor and a predetermined output signal corresponding to threshold temperature set in said processing circuit, and the comparator outputs a signal whose output level differs in dependence upon a comparison result from said output terminal.

15. A printing apparatus using the printhead claimed in claim 1, comprising:

input means for inputting the determination result outputted from said output terminal;

recovery means for performing a recovery operation by discharging ink from said printhead; and

recovery operation control means for terminating a printing operation in accordance with the determination result and controlling said recovery means so as to perform the recovery operation.

16. The apparatus according to claim 15, wherein said recovery means includes suction recovery means for performing the recovery operation by sucking ink from an orifice of said printhead.

17. The apparatus according to claim 15, wherein said recovery means includes pressurization recovery means for performing the recovery operation by applying pressure to an ink flow channel inside of said printhead so as to forcedly to discharge ink.

18. The apparatus according to claim 15, further comprising print control means for controlling said printhead to perform printing.

19. The apparatus according to claim 18, wherein said recovery operation control means comprise comparing means for comparing the determination result and a predetermined threshold, and designates to said print control means to stop a printing operation in accordance with a comparison result by said comparison means as well as designates said recovery means to start operating.

20. A printing apparatus for printing an image on a printing medium by using a printhead which discharges ink from a nozzle, comprising:

input means for inputting a signal indicating a result of determining existence or absence of the ink in the printhead;

recovery means for performing a recovery operation by discharging the ink from the printhead; and

recovery operation control means for terminating a printing operation in accordance with the signal inputted by said input means and controlling said recovery means so as to perform the recovery operation.

21. The apparatus according to claim 20, wherein said recovery means includes suction recovery means for performing the recovery operation by suctioning the ink from an orifice of the printhead.

22. The apparatus according to claim 20, wherein said recovery means includes pressurization recovery means for performing the recovery operation by applying pressure to an ink flow channel inside of said printhead so as to forcedly discharge the ink.

23. The apparatus according to claim 20, further comprising print control means for controlling the printhead to perform printing.

24. The apparatus according to claim 20, wherein the signal inputted by said input means is outputted from the printhead.

25. The apparatus according to claim 24, wherein the printhead includes a circuit sensing a status of the printhead and determining the existence or absence of the ink in the nozzle.

26. The apparatus according to claim 20, wherein the printhead includes an electrothermal transducer, and an electric current pulse is applied to the electrothermal transducer so as to generate heat and discharge the ink by utilizing the generated heat.