Method and compensator for stabilizing an encoder signal

Patent metadata

Field	Value
Publication number	US-10406840-B2
Application number	US-201816023168-A
Country	US
Kind code	B2
Filing date	Jun 29, 2018
Priority date	Jun 29, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

Aspects of the disclosure relate to a method and a compensator via which the input edges of the encoder signal of an encoder may be transformed into a compensated encoder signal such that requirements with regard to a dot resolution of a printing device and with regard to a maximum activation frequency of the dot generators of the printing device are satisfied.

First claim

The invention claimed is:

1. A method for stabilizing at least one encoder signal for the activation of dot generators of a printing device to print dots onto a recording medium, the method comprising:
determining at least one encoder signal by an encoder configured to detect a dimension of a relative movement between the dot generators and the recording medium in a transport direction, the encoder signal including a sequence of input edges, wherein the encoder signal, averaged over time, enables a target dot resolution in the transport direction if the dot generators are activated according to the encoder signal or according to the encoder signal down-clocked by a factor Q, wherein Q is a whole number with Q≥1; and
generating a sequence of output edges of the compensated encoder signal, the sequence corresponding to the sequence of input edges, wherein, upon activation of the dot generators according to the compensated encoder signal or according to the compensated encoder signal down-clocked by the factor Q:
averaged over time, the target dot resolution B in the transport direction is achieved; and
a maximum activation frequency of the dot generators is not exceeded.

2. The method according to claim 1 , further comprising:
generating a corresponding output edge of the compensated encoder signal for each input edge of the encoder signal; and
varying a time interval between output edges relative to a time interval between corresponding input edges.

3. The method according to claim 1 , further comprising:
detecting an input edge of the encoder signal;
increasing an edge count value in reaction to the detection of an input edge;
determining that an output edge of the compensated encoder signal should be generated; and
in response to the determination that an output edge should be generated, reducing the edge count value so that the edge count value indicates a number of input edges for which a corresponding output edge has not yet been generated.

4. The method according to claim 3 , further comprising:
detecting a timing pulse signal of a timing pulse;
increasing a print period count value based on the detection of a timing pulse signal; and
in response to the determination that an output edge should be generated, resetting the print period count value so that the print period count value indicates a time elapsed since the generation of the last output edge.

5. The method according to claim 4 , further comprising:
comparing the print period count value with a minimum count value, wherein:
the minimum count value depends on the maximum activation frequency; and
it is determined that an output edge of the compensated encoder signal should be generated if the print period count value has reached at least the minimum count value and if the edge count value indicates that an input edge has been detected for which an output edge has not yet been generated.

6. The method according to claim 5 , further comprising:
determining the compensated encoder signal down-clocked by the factor Q, with Q>1; and
activating the dot generators with the compensated encoder signal down-clocked by the factor Q,
wherein the timing pulse has a limited time resolution of timing pulse signals, the limited time resolution of the timing pulse causing the whole-number minimum count value calculated from the maximum activation frequency to produce a limited activation frequency of the dot generators that is smaller by a difference frequency from the maximum activation frequency.

7. The method according to claim 6 , further comprising:
reducing the minimum count value for the generation of a portion of the sequence of output edges by a shortening value, the shortening value being limited based on the difference frequency.

8. The method according to claim 1 , wherein:
the encoder signal comprises alternating rising input edges and falling input edges;
the compensated encoder signal is determined such that the compensated encoder signal comprises alternating rising output edges and falling output edges;
a rising output edge and a directly following falling output edge form a period of the compensated encoder signal; and
a period of the compensated encoder signal down-clocked by the factor Q is produced from Q periods of the compensated encoder signal.

9. The method according to claim 8 , wherein:
a minimum period count value for the generation of the rising output edge and the directly following falling output edge of a period of the compensated encoder signal depends on the maximum activation frequency and on the factor Q;
the minimum count value for the generation of the rising output edge and the minimum count value for the generation of the directly following falling output edge is respectively half of the minimum period count value if the minimum period count value is an even number; and
the minimum count value for the generation of the rising output edge or the minimum count value for the generation of the directly following falling output edge is greater by a counter value than the respective other minimum count value if the minimum period count value is an odd number.

10. A non-transitory computer-readable storage medium with an executable program stored thereon, that when executed, causes a processor to perform the method of claim 1 .

11. A compensator operable to determine at least one compensated encoder signal to activate dot generators of a printing device operable to print dots onto a recording medium, the compensator comprising:
a detector configured to receive at least one encoder signal of an encoder to detect a dimension of a relative movement between the dot generators and the recording medium in a transport direction, the encoder signal including a sequence of input edges, wherein the encoder signal, averaged over time, enables a target dot resolution in the transport direction if the dot generators are activated according to the encoder signal or according to the encoder signal down-clocked by a factor Q, wherein Q is a whole number with Q≥1; and
a sequence generator configured to generate a sequence of output edges of the compensated encoder signal, the sequence corresponding to the sequence of input edges, wherein: upon activation of the dot generators according to the compensated encoder signal or according to the compensated encoder signal down-clocked by the factor Q, averaged over time, the target dot resolution is achieved in the transport direction, and a maximum activation frequency of the dot generators is not exceeded.

12. The compensator according to claim 11 , wherein:
the compensator comprises at least one oscillator that is configured to generate a timing pulse with a sequence of chronologically periodic timing pulse signals;
the input edges of the sequence of input edges are chronologically placed at a corresponding sequence of points in time relative to a starting point in time; and
the compensator is further configured to generate the sequence of output edges based on the timing pulse such that the output edges of the sequence of output edges are placed at least in part at different points in time, relative to the starting point in time, than the input edges.

13. A printing system comprising the compensator according to claim 11 .

Assignees

• Oce Holding Bv

Inventors

• Zollner Werner
• Mayr Michael
• Gassner Guenter

Classifications

• B41J11/008

  Controlling printhead for accurately positioning print image on printing material, e.g. with the intention to control the width of margins · CPC title

• H03K5/1534 Primary

  Transition or edge detectors · CPC title

• B41J2/2146

  for line print heads · CPC title

• B41J2/2132

  Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding (methods for local corrections by dot omission, image edge enhancement, or multi-pass mask selection G06K15/102; colour conversion H04N1/40) · CPC title

• B41J29/38 Primary

  Drives, motors, controls or automatic cut-off devices for the entire printing mechanism · CPC title