Media sheet skew correction

Patent metadata

Field	Value
Publication number	US-11401124-B2
Application number	US-201816605513-A
Country	US
Kind code	B2
Filing date	Jul 25, 2018
Priority date	Jul 25, 2018
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

In an example of the disclosure, a driver correction specification is calculated based upon a time differential between a first sensor detection of a first portion of a leading edge of a media sheet and second sensor detection of a second portion of the leading edge. The driver correction specification is for causing skew correction of the media sheet as the media sheet moves along a media path to impact a blocker element. The driver is caused to operate according to the calculated driver correction specification.

First claim

The invention claimed is:

1. A media sheet skew correction system, comprising:
a driver comprising a plurality of rollers situated upon a common shaft to transport a media sheet along a media path;
a first sensor to detect a first portion of a leading edge of the media sheet as the media sheet is transported along the media path;
a second sensor to detect a second portion of the leading edge of the media sheet as the media sheet is transported along the media path;
a blocker element situated orthogonal to the media path and downstream of the first sensor and the second sensor;
a calculation engine to calculate, based upon a time differential between first sensor detection of the first portion and second sensor detection of the second portion, a driver correction specification for causing skew correction of the media sheet as the media sheet impacts the blocker element; and
a correction implementation engine to cause the driver to operate according to the calculated driver correction specification.

2. The media sheet skew correction system of claim 1 , wherein the calculation engine is to calculate the driver correction specification based upon a dimension of the media sheet.

3. The media sheet skew correction system of claim 1 , wherein the driver correction specification includes an amount of time and a speed that the driver is to be engaged to cause a leading corner of the leading edge to impact the blocker element and advance a lagging corner of the leading edge to a position such that the leading edge is horizontal with the blocker element.

4. The media sheet skew correction system of claim 1 , wherein the correction specification includes a number of turns that the rollers are to be engaged.

5. The media sheet skew correction system of claim 1 , wherein the correction implementation engine when implementing the driver correction specification drives each roller of the plurality of rollers at a same speed.

6. The media sheet skew correction system of claim 5 , wherein the driver correction specification includes a change in speed of the rollers of the driver.

7. The media sheet skew correction system of claim 1 , wherein the blocker element is movable into and out of a blocking position.

8. The media sheet skew correction system of claim 1 , wherein the blocker element has a width greater than the width of the media.

9. The media sheet skew correction system of claim 1 , wherein the media path is a bridge between a media sheet pickup component and a print engine.

10. The media sheet skew correction system of claim 1 , wherein the first and second sensors are optical sensors.

11. The media sheet skew correction system of claim 1 , further comprising a third sensor, the third sensor to detect the media sheet as the media sheet is being transported at a first speed, and to trigger correction implementation engine to implement the driver correction specification such that the media sheet is transported at a second speed that is less than the first speed.

12. The media sheet skew correction system of claim 11 , wherein the second speed is approximately 25% of the first speed.

13. A method to correct media sheet skew, comprising
utilizing a first sensor to detect a first portion of a leading edge of a media sheet as the media sheet is transported by a driver along a media path, the driver comprising a plurality of rollers situated upon a common shaft;
utilizing a second sensor to detect a second portion of the leading edge of the media sheet as the media sheet is transported by the driver along the media path;
calculating a correction specification for the driver, the correction specification for causing skew correction of the media sheet as the media sheet impacts a blocker element situated orthogonal to the media path and downstream of the first sensor and the second sensor,
wherein the calculation is on consideration of a time differential between first sensor detection of the first portion and second sensor detection of the second portion and is in consideration of a width of the media sheet; and
causing the driver to implement the calculated correction specification.

14. A printer system, comprising:
a media sheet pickup component;
a print engine,
a media path to bridge between the media sheet pickup component and the print engine;
a driver including a plurality of rollers situated upon a common shaft to transport a media sheet along the media path;
a first sensor to detect a first portion of a leading edge of the media sheet as the media sheet is transported along the media path;
a second sensor to detect a second portion of the leading edge of the media sheet as the media sheet is transported along the media path;
a blocker element situated orthogonal to the media path and downstream of the first sensor and the second sensor;
a calculation engine to calculate a driver correction specification for causing skew correction of the media sheet as the media sheet impacts the blocker element,
wherein the calculation is based upon a time differential between first sensor detection of the first portion and second sensor detection of the second portion, and the calculation is based upon a dimension of the media sheet; and
a correction implementation engine to cause the driver to operate according to the calculated correction specification.

Assignees

• Hewlett Packard Development Co

Inventors

• Nir Jonathan
• Shkalim Hagay

Classifications

• B65H2513/50

  Timing · CPC title

• B65H2511/20

  Location in space · CPC title

• B65H2511/24

  Irregularities, e.g. in orientation or skewness · CPC title

• B65H2301/331

  Skewing, correcting skew, i.e. changing slightly orientation of material · CPC title

• B65H7/06

  responsive to presence of faulty articles or incorrect separation or feed (B65H7/14 takes precedence) · CPC title