Method for determining pixel dropout

Patent metadata

Field	Value
Publication number	US-9102156-B2
Application number	US-201313902193-A
Country	US
Kind code	B2
Filing date	May 24, 2013
Priority date	May 24, 2013
Publication date	Aug 11, 2015
Grant date	Aug 11, 2015

Abstract

A technique is described for determining pixel dropout in a printhead that has a plurality of print elements arrayed along an axis. In the technique, a dataset of integrated intensity values, in the printing direction on a substrate, of a captured image is generated and used to determine if pixel dropout has or may have occurred.

First claim

The invention claimed is:

1. A method of determining pixel dropout of a printhead that has a plurality of print elements arrayed along a first axis, comprising:
printing on surfaces of a plurality of substrates using the printhead by moving the substrates and the printhead relative to one another in a printing direction that is generally perpendicular to the first axis;
using a mechanical image capture device to capture printed on the surfaces of the substrates using the printhead or to capture images of portions of a print ribbon that was used to print the images on the substrates using the printhead;
inputting the captured images into a processing device and using the processing device to generate datasets of integrated intensity values, in a printing direction, of the captured images;
using the datasets to determine if pixel dropout has occurred; and
generating an alert signal if pixel dropout has occurred on a predetermined number of the substrates or print ribbon portions.

2. A method of determining pixel dropout of a printhead that has a plurality of print elements arrayed along a first axis, comprising:
printing on surfaces of a plurality of substrates using the printhead by moving the substrates and the printhead relative to one another in a printing direction that is generally perpendicular to the first axis;
using a mechanical image capture device to capture images printed on the surfaces of the substrates using the printhead or to capture images of portions of a print ribbon that was used to print the images on the substrates using the printhead; Ser. No. 13/902,193
inputting the captured images into a processing device and using the processing device to generate datasets of integrated intensity values, in a printing direction, of the captured images;
using the datasets to determine if pixel dropout has occurred; and
generating an alert signal if pixel dropout has occurred on a predetermined consecutive number of the substrates or print ribbon portions, on a predetermined percentage of the substrates or print ribbon portions, or if an amount of pixel dropout exceeds a predetermined threshold on a predetermined number of the substrates or print ribbon portions.

3. The method of claim 1 , wherein the printed images are monochromatic or multi-color.

4. The method of claim 3 , wherein the captured images are multi-color or monochromatic.

5. The method of claim 4 , further comprising decomposing the captured multi-color images into a plurality of color datasets, each dataset representing an individual color; and
analyzing each of the color datasets to determine if pixel dropout has occurred for a particular color.

6. The method of claim 1 , wherein printing comprises printing using a plurality of the printheads, each printhead printing a CMYK color;
capturing the images printed on the substrate surfaces or the print ribbon portions after one or more of the printheads print; and
for each captured image, generate a dataset of integrated intensity values, in the printing direction, of the respective captured image.

7. The method of claim 1 , wherein each substrate is a plastic card, a page of a passport, or a retransfer film.

8. The method of claim 7 , further comprising performing a verification process on each plastic card, passport page, or retransfer film.

9. The method of claim 8 , wherein the verification process comprises one or more of the following:
verification of printed data;
verification of a printed image;
verification of embossing;
verification of topping;
verification of data on a chip; and
verification of data on a magnetic stripe.

Assignees

• Datacard Corp
• Entrust Datacard Corp

Inventors

• Wagener Thomas J

Classifications

• B41J2/355 Primary

  Control circuits for heating-element selection · CPC title

• B41J2/16579 Primary

  Detection means therefor, e.g. for nozzle clogging · CPC title

• B41J2/32

  using thermal heads · CPC title

• B41J2/0451

  for detecting failure, e.g. clogging, malfunctioning actuator · CPC title

• B41J2/0458

  controlling heads based on heating elements forming bubbles · CPC title