REFLEX PRINTING

• US 20120062641A1
• Filed: 09/14/2010
• Published: 03/15/2012
• Est. Priority Date: 09/14/2010
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: DeJong, Joannes N.M., Williams, Lloyd A.
• Granted Patent: US 8,376,501 B2
• Time in Patent Office: Days
• US Class Current: 347/19
• CPC Class Codes: B41J 11/42 Controlling printing material conveyance for accurate alignment of the printing material with the printhead; Print registering
• CPC Class Codes: B41J 15/16 Means for tensioning or winding the web

Abstract

The present disclosure provides for an imaging system comprising an image receiving surface which is moved in a downstream direction; a first marking station which applies a first image to the image receiving surface; and, a second marking station, downstream of the first marking station, which applies a second image to the image receiving surface. The imaging system further comprises a first measuring device at a first location at a beginning of a platen which outputs velocity measurement information related to the moving image receiving surface; a second measuring device at a second location at an end of the platen which outputs tension measurement information related to a tension increase in the media receiving surface between the first and second locations; and, a control system in communication with the first and second marking stations, the control system being configured for determining a modified actuation time of at least one of the first and second marking stations based on the information provided by the first and second measuring devices.

Claims

1. An imaging system comprising:

an image receiving surface which is moved in a downstream direction;

a first marking station which applies a first image to the image receiving surface;

a second marking station, downstream of the first marking station, which applies a second image to the image receiving surface;

a first measuring device at a first location at a beginning of a platen which outputs velocity measurement information related to the moving image receiving surface;

a second measuring device at a second location at an end of the platen which outputs tension measurement information related to a tension increase in the media receiving surface between the first and second locations; and

,

a control system in communication with the first and second marking stations, the control system being configured for determining a modified actuation time of at least one of the first and second marking stations based on the information provided by the first and second measuring devices.

2. The imaging system of claim 1, further comprising a drive member for moving the image receiving surface between the first and second marking stations and wherein the second measuring device is associated with the drive member.

3. The imaging system of claim 1, wherein the first measuring device is upstream of the first and second marking stations and the second measuring device is downstream of the first and second marking stations.

4. The imaging system of claim 1, wherein the image receiving surface is defined by an extensible medium.

5. The imaging system of claim 1, wherein the imaging surface comprises a surface of a print medium.

6. The imaging system of claim 5, wherein the print medium comprises a paper web.

7. The imaging system of claim 1, wherein the imaging surface comprises a surface of a belt, the images being transferred from the belt to a print medium.

8. The imaging system of claim 1, further comprising a drive nip for moving the image receiving surface and wherein the measuring devices are located no further from the marking stations than the drive nip.

9. The imaging system of claim 1, wherein the first measuring device provides information which enables a variation in at least one of speed and position of the image receiving surface to be monitored and the second measuring device provides information which enables monitoring of a variation in tension of the image receiving surface.

10. The imaging system of claim 1, wherein the first measuring device is selected from the group consisting of an encoder and laser Doppler surface measurement.

11. The imaging system of claim 10, wherein the second measuring device calculates the image receiving surface displacement (Y) based on a drag force (F) according to:

Y=0.5*(F/E)*x²/a;

where,

F equals applied drag force,

E equals the modulus of elasticity of the image receiving surface,

a equals the position at the end of the platen, and,

x equals the distance from the first location.

12. The imaging system of claim 10, wherein the first measuring device comprises an encoder associated with a first roller which rotates as the imaging surface travels in the downstream direction.

13. The imaging system of claim 12, wherein the first roller is upstream of the first and second marking stations.

14. The imaging system of claim 1, wherein the second measuring device in association with a second roller including a servo motor, whereby the servo motor provides a torque in the second location to control the speed in the first location.

15. The imaging system of claim 14, wherein a process direction force profile is applied between the first location and the second location.

16. An imaging system comprising:

an image receiving surface which is moved in a downstream direction;

a first marking station which applies a first image to the image receiving surface;

a second marking station, downstream of the first marking station, which applies a second image to the image receiving surface;

a first measuring device at a first location which outputs velocity measurement information related to the moving image receiving surface;

a second measuring device at a second location which outputs tension measurement information related to a tension increase in the media receiving surface between the first and second locations;

a control system in communication with the first and second marking stations, the control system being configured for determining a modified actuation time of at least one of the first and second marking stations based on the information provided by the first and second measuring devices; and

,

the second measuring device in association with a second roller including

a servo motor, whereby the servo motor provides a torque in the second location to control the speed in the first location.

17. The imaging system of claim 16, wherein a process direction force profile is applied between the first location and the second location.

18. The imaging system of claim 16, wherein the first and second marking stations comprise print heads which eject ink onto the image receiving surface to form the images.

19. A method of registering images, comprising:

moving an image receiving surface;

applying images to the image receiving surface at first and second spaced image applying positions;

monitoring a speed of the image receiving surface at a first monitoring position spaced upstream from the first and second image applying positions;

monitoring a tension in the image receiving surface at a second monitoring position spaced downstream from the first and second image applying positions; and

,

controlling a timing of at least one of the application of the first and second images in response to the monitored speed and tension in the image receiving surface.

20. The method of claim 19, wherein monitoring the tension includes measuring a drag force on the image receiving surface corresponding to an image receiving surface displacement.

21. The method of claim 20, wherein a process direction force profile is applied between the first monitoring position and the second monitoring position.

22. The method of claim 20, wherein the image receiving surface displacement (Y) due to the drag force (F) is calculated as follows:

Y=0.5*(F/E)*x²/a;

where,

F equals applied drag force,

E equals the modulus of elasticity of the image receiving surface,

a equals the position at the end of the platen, and,

x equals the distance from the first location.

23. The method of claim 22, further including a drive motor to supply a torque in the second position to overcome the drag force and to control the speed in the first location.