Media advance

1. Method of calibrating a media drive in a printer, comprising

advancing media through the printer with the media drive while detecting media surface texture to detect media advances within the printer,

determining an error in the media advances,

calibrating the media drive so as to at least partly compensate for the determined error,

advancing a media portion that was used for calibration through the printer and printing on said media portion.

2. Method according to claim 1 , comprising determining drive advances, wherein the error comprises a discrepancy between a media advance and a corresponding drive advance.

3. Method according to claim 2 , comprising

using a processor to convert the detected media advances into media advance signals,

applying a transformation to the detected media advance signals, and

determining a discrepancy between drive advance signals and the corresponding media advance signals.

4. Method according to claim 1 , comprising

stepwise advancing the media, and

detecting an advanced distance of the media surface between each step.

5. Method according to claim 1 , wherein detecting media advances comprises optically detecting the media surface texture and applying pattern recognition to the media surface texture to detect shifts of the media surface.

6. Method according to claim 1 , wherein detecting media advances comprises optically detecting a non-printed media surface texture.

7. Method according to claim 1 , wherein the error corresponds to a deviation in the surface shape of a drive roller.

8. Method according to claim 1 , comprising

advancing the media through the printer using parameters stored in a memory device,

adapting the parameters, at least for a drive angle range associated with the measured error, and

advancing the media through the printer using the adapted parameters.

9. Method according to claim 8 , wherein

the media drive comprises encoder units each corresponding to respective angles of a drive axis, and

each media advance is associated with a number of encoder units through said parameters, the method further comprising

adapting the parameters so that the number of encoder units that is associated with the media advance corresponding to the error is adapted.

10. Method according to claim 1 , comprising

detecting, within the printer, the media advances driven by the calibrated media drive, and

verifying whether the error has decreased.

11. Printer, comprising

a media drive arranged to advance media through the printer,

a memory device storing parameters for controlling the media drive,

a media surface detector embedded in the printer, arranged to detect media surface texture to detect media advances, and

a processor, configured to

determine an error in a detected media advance, and

adapt at least one of the parameters so as to decrease the error,

wherein the printer prints on a media portion used for calibration.

12. Printer according to claim 11 , wherein

the media surface detector is arranged along the media path, and

the media surface detector comprises an optical detector that is arranged to

detect a non-printed media material texture, and

recognize a displacement of the detected media.

13. Printer according to claim 11 , wherein

the media drive comprises an encoder provided with encoder units, each encoder unit corresponding to a respective angle of the media drive,

the memory device stores a drive algorithm configured to associate certain numbers of encoder units to corresponding media advances according to the given parameters, and

the processor is configured to adapt the parameters by correcting the number of encoder units associated with a media advance that contained the error.

14. Media drive calibration system, comprising

a detector arranged to detect a non-printed media material texture,

a memory device storing parameters for outputting drive advance signals for advancing the media over predetermined distances and at least one threshold value corresponding to respective parameters,

a processor configured to

derive the media advance distance from the detector signals,

calculate a media advance error by comparing the derived media advance distance with the corresponding predetermined distance, and

adapt a parameter when the media advance error corresponding to the parameter exceeds said at least one threshold value,

wherein media material advanced through the media drive calibration system is used for printing.