Apparatus for controlling sheet flatness under an imaging system robust to media curl

Patent metadata

Field	Value
Publication number	US-11117774-B2
Application number	US-201916391418-A
Country	US
Kind code	B2
Filing date	Apr 23, 2019
Priority date	Apr 23, 2019
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A system for controlling curl in sheets passing beneath a camera includes applying a thin layer of high velocity air to a curved baffle positioned beneath the camera. The high velocity air layer, which will have a tendency to follow the curved baffle (Coanda effect), will divert sheets (Bernoulli effect) towards the curved baffle. By positioning the curved baffle along the media paper path and by applying a uniform air stream to it, a lower pressure area will be created. This will flatten the trajectory of the sheets and thereby remove curl before the sheets pass the camera.

First claim

What is claimed is:

1. An apparatus for controlling sheet flatness under an imaging system, comprising:
a first transport along which sheets are conveyed;
a second transport along which sheets are conveyed downstream of said first transport;
a curved member positioned between said first and second transports;
a charge coupled device array positioned immediately above said curved member for imaging sheets passing beneath said charge coupled device array; and
a single air flow device that produces a high velocity air stream positioned adjacent said curved member; said air flow device configured to output a layer of high velocity air directly along a surface portion of said curved member such that said high velocity air stream follows said surface portion of said curved member causing said sheets to follow said curved member and simultaneously create a lower pressure band that will flatten said sheets under said imaging system.

2. The apparatus of claim 1 , wherein said charge coupled device array is positioned directly above said curved member.

3. The apparatus of claim 2 , wherein said charge coupled device array is a camera.

4. The apparatus of claim 1 , wherein said high velocity air stream from said air flow device creates a Coanda effect along said surface portion of said curved member.

5. The apparatus of claim 4 , wherein said curved member is a baffle.

6. The apparatus of claim 4 , wherein said curved member is cylindrical in shape.

7. The apparatus of claim 4 , wherein said high velocity air stream from said air flow device is configured to produce Bernoulli effects on said sheets with respect to said curved member.

8. An arrangement for removing curl from sheets conveyed in a paper path, comprising:
a charge coupled array;
a first transport for conveying sheets past said charge coupled array towards a downstream device;
a second transport downstream of and adjacent to said first transport;
a curved member positioned between said first and second transports;
a single air flow device positioned adjacent said curved member; and
wherein said air flow device is configured and located to apply a layer of high velocity air that due to Coanda effect follows along with the sheets a portion of a surface of said curved member and due to the Bernoulli effect constrains the sheets down towards said portion of said surface of said curved member to thereby remove curl from leading edges of the sheets.

9. The apparatus of claim 8 , wherein said curved member is cylindrical.

10. The apparatus of claim 9 , wherein said charged coupled array is a camera.

11. The apparatus of claim 8 , wherein said charged coupled array is a spectrophotometer.

12. The apparatus of claim 11 , wherein said spectrophotometer is positioned directly above a center portion of said curved member.

13. The apparatus of claim 12 , wherein said first and second transports are vacuum transports.

14. The apparatus of claim 12 , wherein said air flow device is positioned with respect to and works in conjunction with said curved member such that a wrap angle of the sheets around said curved member is maintained as the sheets are conveyed past said spectrophotometer.

15. The apparatus of claim 14 , wherein said curved member is semi-circular in shape.

16. A method for removing curl from sheets passing under an imaging system, comprising:
providing a first transport along which sheets are conveyed;
providing a second transport along which sheets are conveyed downstream of said first transport;
providing a curved member positioned orthogonally between said first and second transports;
providing a charge coupled device array positioned immediately above said curved member for imaging sheets passing beneath said charge coupled device array;
providing an air flow device that produces a high velocity air stream over an inboard to outboard length of said curved member positioned adjacent said curved member;
configuring said air flow device such that said high velocity air stream follows a surface portion of said curved member and thereby induces said sheets to follow said surface portion of said curved member; and
equipping said air flow device with nozzles and locating said nozzles with respect to said surface portion of said curved member such that a lower pressure band is created which will flatten said sheets under said imaging system.

17. The method of claim 16 , wherein said curved member is cylindrical.

18. The method of claim 16 , including using said high velocity air stream to bend said sheets to follow said curved member and pull said sheets down onto said curved member.

19. The method of claim 16 , wherein charge coupled device is a spectrophotometer.

20. The method of claim 19 , wherein said high velocity air stream over said inboard to outboard length of said curved member is uniform.

Assignees

• Xerox Corp

Inventors

• Tanchak Rachel Lynn
• Ruiz Erwin
• Terrero Carlos M
• Irizarry Roberto A
• Batchelor Glenn
• Dergham Ali R

Classifications

• B65H2801/39

  Scanning · CPC title

• B65H29/248 Primary

  with coanda effect (separating from a stack B65H3/14) · CPC title

• B65H5/228

  by air-blast devices · CPC title

• B65H2801/06

  Office-type machines, e.g. photocopiers · CPC title

• G03G2215/00662

  Decurling device · CPC title