Method for controlling color separations registration

• US 9,462,162 B2
• Filed: 05/29/2013
• Issued: 10/04/2016
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Oce Printing Systems GmbH & Co KG (Canon Inc.)
• Original Assignee: Oce Printing Systems GmbH & Co KG (Canon Inc.)
• Inventors: Paul, Andreas
• Primary Examiner(s): TRAN, DUNG D
• Application Number:
  US14/400,755
• Publication Number:
  US 20150156376A1
• Time in Patent Office: 1,224 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B41F 33/0081 Devices for scanning register marks
• CPC Class Codes: B41P 2233/52 for registering
• CPC Class Codes: G03G 15/5062 by measuring the characteristics of an image on the copy material
• CPC Class Codes: G03G 2215/00455 Continuous web, i.e. roll
• CPC Class Codes: G03G 2215/0141 the linear arrangement being horizontal
• CPC Class Codes: G03G 2215/0161 Generation of registration marks
• CPC Class Codes: H04N 1/58 Edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction H04N1/62 takes precedence
• CPC Class Codes: H04N 1/6038 for controlling interaction among colorants
• CPC Class Codes: H04N 1/6044 involving a sensor integrated in the machine or otherwise specifically adapted to read the test pattern
• CPC Class Codes: H04N 2201/0005 using a reference pattern designed for the purpose, e.g. a test chart
• CPC Class Codes: H04N 2201/0094 Multifunctional device, i.e. a device capable of all of reading, reproducing, copying, facsimile transception, file transception

Abstract

In a method to control a color printer or color copier, a color separation of a first color and a color separation of a second color are applied to a printing substrate to generate a print image. Also, with aid of a printing unit, at least a first control field is printed on the printing substrate. The first control field has a predetermined pattern that includes at least the first color and the second color and is designed such that a color value of the first control field changes depending on a registration error between the first and the second color separations. A reference field is also printed on the printing substrate, a pattern of the reference field being predetermined such that it has a same color value independent of the registration error. The color value of the first control field is measured with a color value sensor. The color value of the reference field is also measured with the color value sensor and a desired color value is determined depending on the color value of the reference field. A deviation between the measured color value of the first control field and the desired color value is determined, the deviation corresponding to a spatial shift of the color separations. At least one control signal is generated to reduce the spatial shift depending on the determined deviation.

Claims

1. A method to control a color printer or color copier, comprising the steps of:

applying a color separation of a first color and a color separation of a second color to a printing substrate to be printed to in order to generate a print image;

also, with aid of a printing unit, printing at least a first control field on the printing substrate, wherein the first control field has a predetermined pattern that includes at least the first color and the second color and is designed such that a color value of the first control field changes depending on a registration error between the first and the second color separations;

also printing a reference field on the same printing substrate, the reference field having a predetermined pattern including at least the first color and the second color, wherein the pattern of the reference field is designed such that a degree of superposition of the first and the second colors of the pattern of said reference field remains constant independent of the registration error such that the pattern of the reference field has a same color value independent of the registration error;

measuring the color value of the first control field with aid of a color value sensor;

also measuring the color value of the reference field with aid of the color value sensor and determining a desired color value depending on the color value of the reference field;

determining a deviation between the measured color value of the first control field and the desired color value, the deviation corresponding to a spatial shift of the color separations; and

generating at least one control signal to reduce said spatial shift of the color separations depending on the determined deviation.

2. The method according to claim 1 wherein the deviation between the determined color value and the desired color value is determined as a Euclidean distance.

3. The method according to claim 1 wherein:

a second control field is printed on the printing substrate, wherein in the second control field regions inked with the first color are arranged in the pattern of the first control field, and regions inked with the second color are shifted relative to the regions of the first color by a preset value in a preset direction;

a color value of the second control field is determined with aid of the color value sensor;

a deviation between the desired color value and the determined color value of the second control field is determined; and

the control signal is established depending on a deviation between the determined color value of the first control field and the desired color value and a deviation between the determined color value of the second control field and the desired color value.

4. The method according to claim 3 wherein:

a pattern of the second control field is mirror-symmetrical relative to a pattern of the first control field;

with aid of the color value sensor a respective color value of the second control field is measured;

a respective deviation of the color value of the second control field from the desired color value is determined; and

the control signal is established depending on the deviation of the determined color value of the first control field and the determined deviation of the determined color valve of the second control field.

5. The method according to claim 3 wherein:

a color separation of a third color is applied on the printing substrate to be printed to in order to generate the print image;

with the aid of the printing unit, at least another control field is printed on the printing substrate, wherein the another control field has a predetermined pattern that includes the first color and the third color;

a color value of the another control field is measured with aid of the color value sensor;

a deviation between the measured color value of the another control field and the desired color value is determined; and

another control signal to reduce a registration error between the color separation of the first color and the color separation of the third color is established depending on said determined deviation of the determined color value of the another control field from the desired color value.

6. The method according to claim 1 wherein the pattern of the first control field respectively has in alternating fashion a stripe of the first color, a stripe of the second color, and an unprinted stripe.

7. The method according to claim 1 wherein:

a color separation of a third color is applied on a printing substrate to be printed to in order to generate the print image;

a pattern of the first control field includes the third color; and

depending on a determined deviation, a control value of a control signal to reduce a registration error between the color separation of the first color and the color separation of the second color is established, and a control value to reduce a registration error between the color separation of the first color and the color separation of the third color is established.

8. The method according to claim 1 wherein the color value of the reference field that is measured with aid of the color value sensor is used as said desired color value.

9. The method according to claim 1 wherein the desired color value is calculated on the basis of the color value of the reference field that is measured with aid of the color value sensor.

10. The method according to claim 1 wherein the pattern of the reference field is designed such that the degree of superposition of the first and the second colors of the pattern of said reference field remains constant independent of a spatial shift of the first and the second colors of the pattern of said reference field.

11. The method according to claim 1 wherein the pattern of the reference field further includes unprinted portions, wherein a proportion of the unprinted portions of the pattern of the reference field remains constant independent of the registration error such that the pattern of the reference field has the same color value independent of the registration error.

12. The method according to claim 1 wherein proportions of segments of the first color of the pattern of the reference field, segments of the second color of the pattern of the reference field, segments of unprinted portions of the pattern of the reference field, and segments of overlapping portions of the first and second colors of the pattern of the reference field remain constant independent of the registration error such that the pattern of the reference field has the same color value independent of the registration error.

13. The method according to claim 1 wherein proportions of segments of the first color of the pattern of the reference field, segments of the second color of the pattern of the reference field, and segments of overlapping portions of the first and second colors of the pattern of the reference field remain constant independent of the registration error such that the pattern of the reference field has the same color value independent of the registration error.

14. The method according to claim 1 wherein:

the pattern of the reference field comprises first and second segments of the first color and first and second segments of the second color;

the first and the second segments of the first color are symmetrically positioned with respect to an axis;

the first and the second segments of the second color are symmetrically positioned with respect to the axis;

the first segment of the first color overlaps the first segment of the second color and the second segment of the first color overlaps the second segment of the second color; and

a degree of superposition of the first segments and a degree of superposition of the second segments remain constant independent of the registration error such that the pattern of the reference field has the same color value independent of the registration error.

15. A method to control a color printer or color copier, comprising the steps of:

applying a color separation of a first color and a color separation of a second color to a printing substrate to be printed to in order to generate a print image;

also, with aid of a printing unit, printing at least a first control field on the printing substrate, wherein the first control field has a predetermined pattern that includes at least the first color and the second color and is designed such that a color value of the first control field changes depending on a registration error between the first and the second color separations;

also printing a reference field on the printing substrate, a pattern of said reference field being predetermined such that it has a same color value independent of the registration error;

measuring the color value of the first control field with aid of a color value sensor;

also measuring the color value of the reference field with aid of the color value sensor and determining a desired color value depending on the color value of the reference field;

determining a deviation between the measured color value of the first control field and the desired color value, the deviation corresponding to a spatial shift of the color separations;

generating at least one control signal to reduce said spatial shift of the color separations depending on the determined deviation;

a plurality of control fields being printed, wherein in each control field regions of the two colors are shifted relative to one another by a different predetermined value;

determining a color value of each control field with aid of the color value sensor, and respectively calculating a deviation from the desired value;

selecting a control field with a smallest deviation;

multiplying a value by which regions of the two colors are shifted relative to one another in the selected control field by negative one and establishing the multiplied value as a value for an additional registration error; and

establishing a control variable depending on actual registration error.

16. A method to control a color printer or color copier, comprising the steps of:

applying a color separation of a first color and a color separation of a second color to a printing substrate to be printed to in order to generate a print image;

also, with aid of a printing unit, printing at least a first control field on the printing substrate, wherein the first control field has a predetermined pattern that includes at least the first color and the second color and is designed such that a color value of the first control field changes depending on a registration error between the first and the second color separations;

also printing a reference field on the same printing substrate, the reference field having a predetermined pattern including at least the first color and the second color, wherein the pattern of the reference field is designed such that a degree of superposition of the first and the second colors of the pattern of said reference field remains constant independent of the registration error such that the pattern of the reference field has a same color value independent of the registration error;

measuring the color value of the first control field;

also measuring the color value of the reference field and determining a desired color value depending on the color value of the reference field;

determining a deviation between the measured color value of the first control field and the desired color value, the deviation corresponding to a spatial shift of the color separations; and

generating at least one control signal to reduce said spatial shift of the color separations depending on the determined deviation.