Printer with two scanners

Patent metadata

Field	Value
Publication number	US-10165150-B2
Application number	US-201315038003-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Nov 22, 2013
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A printer (300) is disclosed. The printer has two scanners (336, 338) in the paper path of the printer located after the print zone (346). The two scanners are spaced apart from each other by a known distance A and overlap each other in a direction perpendicular to the media axis of travel. The two scanners capture a first and second image of the media.

First claim

What is claimed is:

1. A printer, comprising:
a paper path, the paper path having a media feeding position and a media take-up position;
a print zone located between the media feeding position and the media take-up position;
a first scanner and a second scanner located in the paper path between the print zone and the media take-up position, the first scanner offset from the second scanner along a media axis of motion by a distance A, the first scanner overlapping the second scanner on the media axis of motion, the first scanner to capture a first image of a first side of media, the second scanner to capture a second image of the first side of the media, and
wherein the first scanner and the second scanner have equal exposure times and the exposure time is a constant and the first image and the second image are captured starting at time t 0 ; and
a controller to calculate the scaling of the images along a length of the media by comparing the overlapped area in the first image to the overlapped area in the second image.

2. The printer of claim 1 , wherein the scaling S is equal to V m /V a where V m is a measured velocity of the media between the first and second scanners and V a is an average velocity of the media in the paper path.

3. The printer of claim 1 , wherein the scaling is determined by the difference in a location of at least one reference mark in the first image and a location of the at least one reference mark in the second image.

4. The printer of claim 3 , wherein the at least one reference mark is selected from the group of reference marks comprising: a line printed on the media, a line of text printed on the media, an edge of an image printed on the media.

5. The printer of claim 3 , wherein the at least one reference mark is printed with a marking material not visible to the human eye.

6. The printer of claim 1 , wherein the scaling is used to calculate a distance between two objects printed on the media.

7. The printer of claim 1 , wherein distance A is between 50 and 90 mm.

8. The printer of claim 1 , wherein the first scanner and the second scanner each comprise two separate units spaced apart along a width of the paper path.

9. The printer of claim 8 , wherein a portion of each separate scanner unit of each scanner overlaps along the media axis of motion with a portion of another separate scanner unit of the other scanner.

10. The printer of claim 1 , the controller further to adjust a location of a subsequent printed image on the media based on the calculation of the scaling of a previous image along the length of the media.

11. A method of printing, comprising:
printing a reference mark onto media in a print zone of a paper path;
scanning a first image of the reference mark with a first scanner from a first location in the paper path, where the first location is between the print zone and a media take-up location;
scanning a second image of the reference mark with a second scanner from a second location in the paper path, where the second location is between the first location and the media take-up location; and
calculating the speed of the media in the paper path between the first and second scanners using the location of the reference mark in the first and second images;
wherein the first scanner and the second scanner have equal exposure times and the exposure time is a constant and the first image and the second image are captured starting at time t 0 .

12. The method of claim 11 , wherein the reference mark is selected from the group of reference marks comprising: a line, a line of text, an edge of an image.

13. The method of claim 11 , wherein the reference mark is printed with a marking material not visible to the human eye.

14. The method of claim 11 , wherein the media is a web of media.

15. The method of claim 11 , wherein the first scanner and the second scanner each comprise two separate scanner units spaced apart along a width of the paper path, and a portion of each separate scanner unit of each scanner overlaps along the media axis of motion with a portion of another separate scanner unit of the other scanner.

16. The method of claim 15 , the method further comprising stitching together data from the first and second scanners to produce the first and second images.

17. The method of claim 11 , the method further comprising adjusting a location of a subsequent printed image on the media based on the calculation of the speed of the media in the paper path.

18. A non-transitory computer readable medium containing computer executable instructions, that when executed by a processor in a printer, performs the following method, comprising:
printing a reference mark onto media in a print zone of a paper path;
scanning a first image of the reference mark with a first scanner from a first location in the paper path, where the first location is between the print zone and a media take-up location;
scanning a second image of the reference mark with a second scanner from a second location in the paper path, where the second location is between the first location and the media take-up location,
wherein the first scanner and the second scanner have equal exposure times and the exposure time is a constant and the first image and the second image are captured starting at time t 0 ;

calculating the speed of the media in the paper path between the first and second scanners using the location of the reference mark in the first and second images; and
adjusting a location of a subsequent printed image on the media based on the calculation of the speed of the media in the paper path.

Assignees

• Hp Indigo Bv

Inventors

• Waidman Ran
• Refael Sagi
• Katz Lior

Classifications

• H04N1/00705

  at a plurality of spaced apart locations, e.g. as a sheet is fed through the apparatus · CPC title

• H04N1/0473

  in subscanning direction, e.g. picture start or line-to-line synchronisation · CPC title

• H04N1/0005

  in service, i.e. during normal operation · CPC title

• H04N1/00068

  Calculating or estimating · CPC title

• H04N2201/04713

  Details of the detector arrangement, e.g. non-standard position, optical details (H04N2201/04712 takes precedence) · CPC title