Integrated printing/scanning system using invisible ink for document tracking

• US 6,644,764 B2
• Filed: 10/28/1998
• Issued: 11/11/2003
• Est. Priority Date: 10/28/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Stephens, Ronald D. Jr.
• Primary Examiner(s): Meier, Stephen D.
• Assistant Examiner(s): Huffman, Julian D.
• Application Number:
  US09/181,589
• Publication Number:
  US 20020063744A1
• Time in Patent Office: 1,840 Days
• Field of Search: 235/462, 235/491, 235/468, 347/2, 347/3, 347/98, 347/107, 347/19, 399/2
• US Class Current: 347/3
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/0614 the marking being selective to wavelength, e.g. color barcode or barcodes only visible under UV or IR methods or arrangements for sensing record carriers using a selected wavelength, see G06K7/12
• CPC Class Codes: G06K 5/02 the verifying forming a part of the marking action
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

A document printing and verification system and method. The system includes a printing apparatus for printing an image on a print medium, and an inkjet printer apparatus for printing an invisible identification pattern such as a barcode on the print medium which is invisible to the naked eye under normal ambient illumination. A scanner apparatus is positioned for producing an image of the identification image for verification use. The scanner apparatus includes a light source for illuminating an imaging zone with light including nonvisible energy components and a camera sensitive to nonvisible light from the print medium to form an image of the nonvisible identification image. The inkjet printhead is a high resolution printhead adapted to provide inkjet barcode printing resolution at least as high as 600 dots per inch, improving edge acuity of the pattern, and permits very high density information to be imprinted on the document page. The inkjet ink includes a UV dye and an FR/IR dye. The UV dye when illuminated with UV light provides an image of the barcode which is visible to the naked eye. The FR/IR dye is imaged using an FR/IR camera to capture electronically an image of the barcode.

Claims

1. A document printing and verification system, comprising:

a document printing apparatus for printing multi-page documents including text on print media;

an inkjet printer apparatus comprising an inkjet printhead adapted to emit ink droplets of an invisible ink which is not visible to the unaided eye when viewed with natural light illumination for printing on each page of the multi-page document an invisible identification pattern which is not visible to the unaided eye when viewed with natural light;

a scanner apparatus positioned for producing an image of said identification image for verification use, said scanner apparatus including a light source for illuminating an imaging zone with light including nonvisible energy components and a camera sensitive to nonvisible light from the print media to form an image of said nonvisible identification image; and

a system controller for controlling the document printing apparatus and the inkjet printing apparatus and responsive to image signals from the scanner apparatus to verify the presence of each page of the multi-page document imprinted with said identification pattern.

2. The system of claim 1 wherein the inkjet printhead is a high resolution printhead adapted to provide inkjet printing resolution at least as high as 600 dots per inch.

3. The system of claim 1 wherein said ink droplets emitted by said printhead include a far red (FR)/infrared (IR) dye which produces FR/IR emissions in response to illumination in an FR/IR wavelength band, and said camera is sensitive to FR/IR emissions of said dye to form said image of said identification pattern which has been imprinted on said print media.

4. The system of claim 3 wherein said light source includes a halogen lamp.

5. The system of claim 1 wherein said printhead is positioned adjacent a first surface of said print media to print the identification pattern on said first surface, and said light source comprises a first illumination source positioned adjacent a first side of the camera to provide a first side illumination of the imaging zone, a first optical filter positioned in a first light path between the first source and the imaging zone, and a second illumination source positioned adjacent a second side of the camera to provide a second side illumination of the imaging zone, a second optical filter positioned in a second light path between the second source and the imaging zone, and a third optical filter disposed between a third light path between the imaging zone and the camera.

7. The system of claim 1 wherein said ink droplets emitted by said printhead include a UV dye which is excited by illumination in a UV wavelength band, and said identification pattern becomes visible to the unaided eye when illuminated by light in the UV wavelength band.

8. The system of claim 1 wherein the scanner apparatus includes a first optical filter positioned between the light source and the imaging zone, and a second optical filter positioned between the imaging zone and the scanner apparatus.

9. The system of claim 1 wherein the scanner apparatus further includes optical filtering apparatus for blocking the nonvisible energy components from the light source from the camera.

10. The system of claim 9 wherein said optical filtering apparatus includes a first optical filter disposed in an illumination path between said light source and the imaging zone and a second optical filter disposed between the imaging zone and the camera.

11. The system of claim 1 wherein said identification pattern is a barcode pattern.

12. The system of claim 11 wherein said barcode pattern is a one dimensional barcode pattern, and said scanner apparatus includes a barcode reader.

13. The system of claim 11 wherein said barcode pattern is a two dimensional barcode pattern.

6. The system of claim 6 Therein said ink droplets emitted by said printhead include a far red (FR)/infrared (IR) dye which is excited by illumination in an FR/IR wavelength band, and said camera is sensitive to excitation of said dye to produce an identification pattern image of said excited FR/IR dye which has been imprinted on said print media.

14. A document printing and verification system, comprising:

a medium path along which pages of a print medium are passed;

an electrophotographic printer for printing a multi-page document including text on said pages of said print medium;

an inkjet printer apparatus positioned along the medium path downstream of the electrophotographic printer, said printer apparatus comprising an inkjet printhead adapted to emit ink droplets of an ink which is not visible under natural illumination for printing an invisible barcode on said pages of the print medium which is invisible to the unaided eye under natural illumination;

a scanner apparatus positioned along the medium path downstream of the inkjet printer apparatus for producing an image of the barcode printed on each page of the multi-page document for verification use, said scanner apparatus including a light source for illuminating an imaging zone along said medium path with light including nonvisible energy components and a camera sensitive to illumination light from the print medium to form an image of said nonvisible barcode; and

a system controller for controlling the electrophotographic printer and the inkjet printing apparatus and responsive to image signals from the scanner apparatus to verify the presence of barcoded print media and that each page of the multi-page document is accounted for.

15. The system of claim 14 wherein said ink droplets emitted by said printhead include a far red (FR)/infrared (IR) dye which is excited by illumination in an FR/IR wavelength band, and said camera is sensitive to excitation of said dye to produce a barcode image of said excited FR/IR dye which has been imprinted on said print medium.

16. A document printing and verification system, comprising:

a document printing apparatus for printing multi-page documents including text on print media;

an inkjet printer apparatus comprising an inkjet printhead adapted to emit ink droplets of an invisible ink which is not visible to the unaided eye when viewed with natural light illumination for printing on each page of the multi-page document an invisible identification pattern which is not visible to the unaided eye when viewed with natural light, said ink droplets emitted by said printhead including a far red (FR)/infrared (IR) dye which produces FR/IR emissions in response to illumination in an FR/IR wavelength band, said printhead positioned adjacent a first surface of said print media to print the identification pattern on said first surface of each page;

a scanner apparatus positioned for producing an image of said identification image for verification use, said scanner apparatus including a light source for illuminating an imaging zone with light including nonvisible energy components and a camera sensitive to nonvisible light from the print media to form an image of said nonvisible identification image, said camera sensitive to FR/IR emissions of said dye to form said image of said identification pattern which has been imprinted on said print media;

wherein said light source comprises a source of FR/IR energy positioned adjacent a second surface of said print media at the imaging zone to provide a backside illumination of the imaging zone, and said camera is positioned adjacent said first surface, said light source adapted to pass sufficient FR/IR energy through the print media to excite said FR/IR dye in said ink forming said identification pattern; and

a system controller for controlling the inkjet printing apparatus and responsive to image signals from the scanner apparatus to verify the presence of each page of the multi-page document imprinted with said identification pattern.

17. A method for document printing and verification, comprising the following steps:

printing a multi-page document with text visible to the unaided eye under natural light illumination;

printing an identification pattern on a first surface of each page of said document using an inkjet printer, said pattern printed with ink which is invisible to the unaided eye under natural light illumination, said ink including an far red (FR)/infrared (IR) dye which is excited by FR/IR energy;

illuminating a second surface of each document page with light energy including FR/IR energy to pass sufficient FR/IR energy through said page to excite the identification pattern formed by said ink including an FR/IR dye;

electronically capturing an image of said identification pattern on said first surface for each document page at said imaging zone by imaging said identification pattern onto a camera sensitive to FR/IR energy; and

performing a verification procedure using said electronically captured image for each page to verify that all pages of the multi-page document are accounted for.

18. The method of claim 17 wherein said printing step includes printing the identification pattern with a high resolution printhead to provide a resolution of at least 600 dots per inch.

19. The method of claim 17 wherein the identification pattern comprises a barcode pattern.

20. A document printing and verification system, comprising:

a document printing apparatus for printing multi-page documents including text on print media;

an inkjet printing apparatus comprising an inkjet printhead adapted to emit ink droplets of an invisible ink which is not visible to the unaided eye when viewed with natural light illumination, said inkjet printing apparatus for printing on each page of the multi-page document an invisible identification pattern which is not visible to the unaided eye when viewed with natural light, said droplets including a UV dye and a far red (FR)/infrared (IR) dye, said UV dye when excited by illumination in an UV wavelength band causing said identification pattern to be visible to the unaided eye, said far red (FR)/infrared (IR) dye producing FR/IR emissions in response to illumination in an FR/IR wavelength band;

a scanner apparatus for producing an image of said identification image for verification use, said scanner apparatus including a light source for illuminating an imaging zone with light including nonvisible energy components in said FR/IR wavelength band and a camera sensitive to excitation of said dye to produce an identification pattern image of said excited FR/IR dye which has been imprinted on said print medium; and

a system controller for controlling the document printing apparatus and the inkjet printing apparatus and responsive to image signals from the scanner apparatus to verify the presence of each page of the multi-page document imprinted with said identification pattern.

21. The system of claim 20, including a source of UV radiation to illuminate the print medium and cause the identification image to be visible to the unaided eye to provide a visual indication of operability of the inkjet printing appa.

22. The system of claim 20, wherein the inkjet printhead is a high resolution printhead for providing inkjet printing resolution at least as high as 600 dots per inch.

23. The system of claim wherein said identification pattern is a barcode pattern.

24. A method for document printing and verification, comprising:

printing a multi-page document with text visible to the unaided eye under natural light illumination;

printing an identification pattern on each page of said document using an inkjet printhead emitting ink droplets of an invisible ink, said pattern invisible to the unaided eye under natural light illumination, the droplets including a UV dye and a far red (FR)/infrared (IR) dye, said UV dye when excited by illumination in an UV wavelength band causess said identification pattern to be visible to the unaided eye, said FR/IR dye producing FR/IR emissions in response to illumination in an FR/IR wavelength band;

illuminating one or more pages of the document with UV radiation to cause the identification pattern to be visible to the unaided eye to provide a visual check of said identification pattern printing;

illuminating each document page with light energy including energy components in the FR/IR wavelength band;

electronically capturing an image of said identification pattern for each document page at an imaging zone; and

performing a verification procedure using said electronically captured image for each page to verify that all pages of the multi-page document are accounted for.

25. The method of claim 24, wherein said identification pattern printing includes:

printing the identification pattern on a first surface of the document page; and

said electronically capturing an image includes positioning a camera adjacent the imaging zone to be adjacent said first surface of said document page when the document page is positioned at the imaging zone.

26. The method of claim 25 wherein said illuminating each document page with light energy including energy components in the FR/IR wavelength band includes illuminating said first surface of said document page with said FR/IR energy components.

27. The method of claim 25, wherein said illuminating each document page with light energy including energy components in the FR/IR wavelength band includes positioning an illumination source of FR/IR adjacent a second surface of the document page when positioned at the imaging zone, and passing sufficient FR/IR energy through the document page to excite said FR/IR dye in said ink.