Ground structure for temperature-sensing resistor noise reduction

• US 20060001689A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Scott N. Barker
• Inventors: Parish, George K., Ahne, Adam Jude, Rowe, Kristi M.
• Granted Patent: US 7,871,143 B2
• Time in Patent Office: Days
• US Class Current: 347/19
• CPC Class Codes: B41J 2/1753 Details of contacts on the cartridge, e.g. protection of contacts
• CPC Class Codes: B41J 2/17553 Outer structure

Abstract

An inkjet printhead. The inkjet printhead includes a temperature-sensing resistor with a low voltage end which is connected to a ground structure that at least partially encloses the temperature sensing resistor.

Claims

1. An inkjet printhead comprising:

a temperature sensing resistor configured to have a low voltage end; and

a ground structure at least partially enclosing the temperature sensing resistor and coupled to the temperature sensing resistor at the low voltage end.

2. The inkjet printhead of claim 1, further comprising an ejector chip ground spaced apart from the ground structure.

3. The inkjet printhead of claim 2, further comprising a printhead ground electrically coupled the ground structure and configured to bypass the ejector chip ground.

4. The inkjet printhead of claim 1, further comprising a heater positioned adjacent the ground structure, and configured to generate heat.

5. The inkjet printhead of claim 1, further comprising a transducer configured to be energized and to eject ink.

6. The inkjet printhead of claim 1, further comprising a field effect transistor (“

FET”

) positioned adjacent the ground structure.

7. The inkjet printhead of claim 1, and wherein the temperature sensing resistor comprises N-type material implanted in a P-type substrate.

8. The inkjet printhead of claim 1, and wherein the ground structure comprises a P-type material.

9. An inkjet printing apparatus comprising:

a printing apparatus ground; and

a printhead having a printhead chip ground and a ground structure at least partially enclosing a temperature sensing resistor, the temperature sensing resistor having a low voltage end being coupled to the ground structure and the printing apparatus ground thereby bypassing the printhead chip ground.

10. The inkjet printhead of claim 9, further comprising a heater positioned adjacent the ground structure, and configured to generate heat.

11. The inkjet printhead of claim 9, further comprising a transducer configured to be energized and to eject ink.

12. The inkjet printhead of claim 9, further comprising a field effect transistor (“

FET”

) positioned adjacent the ground structure.

13. The inkjet printhead of claim 9, and wherein the temperature sensing resistor comprises N-type material implanted in a P-type substrate.

14. The inkjet printhead of claim 9, and wherein the ground structure comprises a P-type material.

15. An ejector chip comprising:

an ejector chip ground configured to have a first ground potential of the ejector chip;

a bond pad electrically spaced apart from the ejector chip ground and configured to be coupled to a second ground having a second ground potential;

a ground structure coupled to the bond pad thereby having the second ground potential; and

a temperature sensing resistor coupled to the bond pad thereby also having the second ground potential.

16. The inkjet printhead of claim 15, and wherein the bond pad electrically couples the ejector chip to a printing apparatus ground and thereby bypasses the ejector chip ground.

17. The inkjet printhead of claim 15, further comprising a heater positioned adjacent the ground structure, and configured to generate heat.

18. The inkjet printhead of claim 15, further comprising a transducer configured to be energized and to eject ink.

19. The inkjet printhead of claim 15, further comprising a field effect transistor (“

FET”

) positioned adjacent the ground structure.

20. The inkjet printhead of claim 15, and wherein the temperature sensing resistor comprises N-type material implanted in a P-type substrate.

21. The inkjet printhead of claim 15, and wherein the ground structure comprises a P-type material.

22. A method of reducing noise in a temperature sensing resistor implanted on an ejector chip having an ejector chip ground, the method comprising the acts of:

determining a lower voltage end electrically spaced apart from the ejector chip ground at the temperature sensing resistor;

at least partially enclosing the temperature sensing resistor with a ground structure; and

connecting the ground structure to the lower voltage end of the temperature sensing resistor.

23. The method of claim 22, further comprising the act of coupling the lower voltage end of the temperature sensing resistor to a printer ground different from the ejector chip ground.

24. The method of claim 22, and wherein at least partially enclosing the temperature sensing resistor further comprises the act of implanting a P-type material in the temperature sensing resistor.

25. The method of claim 22, further comprising the act of positioning a transducer adjacent the ground structure.

26. The method of claim 22, further comprising the act of positioning a field effect transistor (“

FET”

) adjacent the ground structure.

27. The method of claim 22, and wherein the temperature sensing resistor further comprises an N-type material implanted in a P-type substrate.