Ground structure for temperature-sensing resistor noise reduction

• US 7,871,143 B2
• Filed: 06/30/2004
• Issued: 01/18/2011
• Est. Priority Date: 06/30/2004
• Status: Expired due to Fees

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Inventors: Parish, George K., Ahne, Adam Jude, Rowe, Kristi M.
• Primary Examiner(s): Nguyen; Lam S
• Application Number:
  US10/883,426
• Publication Number:
  US 20060001689A1
• Time in Patent Office: 2,393 Days
• Field of Search: 347/14, 347/58, 347/67, 347/5, 347/9, 347/17, 347/19, 732/042.6, 296/12, 438/585
• US Class Current: 347/17
• 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:

an array of printing elements;

an array of driving elements for driving the array of printing elements;

a temperature sensing resistor adjacently extending along the arrays and positioned between the arrays for sensing heat generated from the printing elements, and configured to have a low voltage end; and

a ground structure coupled to the temperature sensing resistor at the low voltage end and at least partially enclosing the temperature sensing resistor to electrically shield the temperature sensing resistor from an electrical ground potential of an ejector chip of the printhead, the array of driving elements spacing the temperature sensing resistor from the electrical ground potential.

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

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

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

FET”

) positioned adjacent the ground structure.

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

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

7. An inkjet printing apparatus comprising:

a printing apparatus ground; and

a printhead having;

an array of printing elements;

an array of driving elements for driving the array of printing elements;

a printhead chip ground; and

a ground structure at least partially enclosing a temperature sensing resistor adjacently extending along the arrays and positioned between the arrays for sensing heat generated from the printing elements, to electrically shield the temperature sensing resistor from the printhead chip ground, the array of driving elements spacing the temperature sensing resistor from an electrical ground potential of the printhead chip ground, wherein 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.

8. The inkjet printing apparatus of claim 7, further comprising a heater positioned adjacent the ground structure, and configured to generate heat.

9. The inkjet printing apparatus of claim 7, further comprising a transducer configured to be energized and to eject ink.

10. The inkjet printing apparatus of claim 7, further comprising a field effect transistor (“

FET”

) positioned adjacent the ground structure.

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

12. The inkjet printing apparatus of claim 7, and wherein the ground structure comprises a P-type material.

13. A method of reducing noise in a temperature sensing resistor for sensing heat generated from an array of printing elements in a printhead, the temperature sensing resistor is implanted adjacently extending along and between the array of printing elements and an array of driving elements spacing the temperature sensing resistor from an electrical ground potential of a printhead chip ground of the printhead, the method comprising the acts of:

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

at least partially enclosing the temperature sensing resistor with a ground structure to electrically shield the temperature sensing resistor from the electrical ground potential of the printhead chip ground; and

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

14. The method of claim 13, 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.

15. The method of claim 13, 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.

16. The method of claim 13, further comprising the act of positioning a transducer adjacent the ground structure.

17. The method of claim 13, further comprising the act of positioning a field effect transistor (“

FET”

) adjacent the ground structure.

18. The method of claim 13, and wherein the temperature sensing resistor further comprises an N-type material implanted in a P-type substrate.