Capacitive toner level detection

• US 6,670,817 B2
• Filed: 06/07/2001
• Issued: 12/30/2003
• Est. Priority Date: 06/07/2001
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Heidelberger Druckmaschinen Ag
• Inventors: Beehler, Todd C., Anthony, James D., Fournier, John C.
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Teresinski, John
• Application Number:
  US09/876,664
• Publication Number:
  US 20020186027A1
• Time in Patent Office: 936 Days
• Field of Search: 324/662, 324/133, 324/658, 324/660, 324/661, 324/671
• US Class Current: 324/662
• CPC Class Codes: G03G 15/0856 Detection or control means for the developer level
• CPC Class Codes: G03G 15/086 the level being measured by electro-magnetic means
• CPC Class Codes: G03G 15/0881 Sealing of developer cartridges

Abstract

A container having an electrically conductive container body. The container body defines a container cavity. A sensor assembly is disposed within said container cavity. The sensor assembly is electrically isolated from the container body, and is configured for sensing a level of material within the container cavity.

Claims

1. A container, comprising:

a container having an electrically conductive body enclosing a cavity for receiving and holding solid particles of a material; and

a sensor assembly disposed within said container, said sensor assembly being electrically isolated from said body, said sensor assembly configured for sensing a level of solid particles of the material within said container cavity, said sensor assembly comprising a capacitive sensor and having a first electrode plate and a second electrode plate spaced apart from said first electrode plate to present opposing surfaces to each other, said fist electrode plate configured for being electrically connected to a virtual ground and said second electrode plate configured for being connected to a voltage signal source, said opposing surfaces of the two plates coated with a non-stick coating to inhibit particles of material between the plates from adhering to surfaces of the plates wherein the plates form a capacitor having a capacitance dependent upon the level of the solid particles of material between the two plates.

2. The container of claim 1 wherein said plates are oriented substantially parallel to each other.

3. The container of claim 1 wherein the body is made of conductive material and the plates are electrically isolated from said body.

4. The container of claim 1 wherein said non-stick coating comprises polytetrafluoroethylene.

5. The container of claim 1 wherein each plate is disposed a predetermined depth from a bottom of said container.

6. The container of claim 1, further comprising:

an electrical cable having a plurality of conductors, each of said plurality of conductors electrically connected at a first end thereof to a respective one of said first electrode and said second electrode, an electrical connector electrically connected to a second end of each of said plurality of conductors.

7. The container of claim 6, wherein said container body defines an orifice, said electrical cable extending through said orifice.

8. The container of claim 7, further comprising a sealing member for sealingly engaging each of said orifice and said electrical cable.

9. The container of claim 1, further comprising a ground wire attachment means, said ground wire attachment means configured for receiving and retaining a ground wire to thereby electrically connect said container body to a ground potential.

10. The container of claim 1, wherein said ground wire attachment means is one of affixed to and integral with said conductive container body.

11. The container of claim 1, wherein said sensor assembly is mechanically secured to said container body by electrically nonconductive fastening means.

12. An electrophotographic printing machine, comprising:

at least one waste container having an electrically conductive container body, said container body defining a container cavity; and

a sensor assembly disposed within said container, said sensor assembly being electrically isolated from said body, said sensor assembly configured for sensing a level of solid particles of the material within said container cavity, said sensor assembly comprising a capacitive sensor and having a first electrode plate and a second electrode plate spaced apart from said first electrode plate to present opposing surfaces to each other, said fist electrode plate configured for being electrically connected to a virtual ground and said second electrode plate configured for being connected to a voltage signal source, said opposing surfaces of the two plates coated with a non-stick coating to inhibit particles of material between the plates from adhering to surfaces of the plates wherein the plates form a capacitor having a capacitance dependent upon the level of the solid particles of material between the two plates.

13. The electrophotographic printing machine of claim 12, wherein said non-stick coating comprises polytetrafluoroethylene.

14. The electrophotographic printing machine of claim 12, further comprising:

an electrical cable having a plurality of conductors, each of said plurality of conductors electrically connected at a first end thereof to a respective one of said first electrode and said second electrode, an electrical connector electrically connected to a second end of each of said plurality of conductors.

15. The electrophotographic printing machine of claim 12, further comprising a ground wire attachment means, a ground wire attached at a first end thereof to said ground wire attachment means and at a second end thereof to a chassis of said electrophotographic printing machine to thereby electrically connect said container body to ground potential.

16. An electrophotographic printing engine having stations for charging a photoconductor, selectively discharging portions of the charged photoconductor to form a latent electrostatic image, developing the latent image with solid electrophotographic toner particles, transferring the developed image to a copy sheet and fixing the developed image on the copy sheet, wherein the printing engine further comprises a toner level sensor, comprising:

at least one waste container having an electrically conductive container body, said container body defining a container cavity for holding solid electrophotographic toner particles; and

a sensor assembly disposed within said container, said sensor assembly being electrically isolated from said body, said sensor assembly configured for sensing a level of said solid electrophotographic toner particles within said container cavity, said sensor assembly comprising a capacitive sensor and having a first electrode plate and a second electrode plate spaced apart from said first electrode plate to present opposing surfaces to each other, said fist electrode plate configured for being electrically connected to a virtual ground and said second electrode plate configured for being connected to a voltage signal source, said opposing surfaces of the two plates coated with a non-stick coating to inhibit solid toner material particles between the plates from adhering to surfaces of the plates wherein the plates form a capacitor having a capacitance dependent upon the level of the solid toner particles between the two plates.

17. The electrophotographic printing engine of claim 16, wherein said non-stick coating comprises polytetrafluoroethylene.

18. The electrophotographic printing engine of claim 16, further comprising:

an electrical cable having a plurality of conductors, each of said plurality of conductors electrically connected at a first end thereof to a respective one of said first electrode and said second electrode, an electrical connector electrically connected to a second end of each of said plurality of conductors.

19. The electrophotographic printing engine of claim 16, further comprising a ground wire attachment means, a ground wire attached at a first end thereof to said ground wire attachment means and at a second end thereof to a chassis of said electrophotographic printing machine to thereby electrically connect said container body to ground potential.