Adjustment of shift of dot position of printer

• US 20020113985A1
• Filed: 01/30/2002
• Published: 08/22/2002
• Est. Priority Date: 05/30/2000
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Tayuki, Kazushige
• Granted Patent: US 7,198,347 B2
• Time in Patent Office: Days
• US Class Current: 358/1.9
• CPC Class Codes: B41J 19/145 Dot misalignment correction
• CPC Class Codes: B41J 2/15 for serial printing
• CPC Class Codes: B41J 2/2135 Alignment of dots
• CPC Class Codes: B41J 29/393 Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns

Abstract

The object of the present invention is to adjust relative misalignment of recording positions of dots created at different timings with high accuracy, thereby enhancing the printing quality.

A patch pattern is used as a test pattern for adjusting misalignment of recording positions between a first dot and a second dot created at different timings. In the test pattern, a fraction of the first dot and the second dot adjoining to each other in either a main scanning direction or a sub-scanning direction may be significantly greater than a fraction of the first dots or the second dots adjoining to each other. In the test pattern, substantially equal numbers of the first dot and the second dot may be created with a substantially equivalent dispersibility over a practically whole area.

Claims

1. A print control apparatus that supplies print data to a printing device, which creates dots and thereby carries out printing,

said printing device comprising:

a print head having multiple nozzles, from which ink is ejected;

a scanning module that carries out main scan and sub-scan of said print head; and

a driving module that drives said print head during each scan and causes at least two different types of dots, a first dot and a second dot, to be created at different timings in respective pixels,

said print control apparatus comprising;

a test pattern data generation module that generates test pattern data used for printing a predetermined test pattern,

wherein the test pattern is a patch pattern, in which dots are created at a preset recording rate in a predetermined area and a fraction of the first dot and the second dot adjoining to each other in either of a main scanning direction and a sub-scanning direction is significantly greater than a fraction of the first dots or the second dots adjoining to each other.

2. A print control apparatus in accordance with claim 1, wherein the first dot and the second dot are created with nozzles having different positions in the main scanning direction.

3. A print control apparatus in accordance with claim 1, wherein said driving module drives said print head in both a forward pass and a backward pass of the main scan,

the first dot is a forward dot created in the forward pass, and the second dot is a backward dot created in the backward pass.

4. A print control apparatus in accordance with claim 1, wherein the test pattern includes the first dot and the second dot arranged checkerwise.

5. A print control apparatus in accordance with claim 1, wherein the preset recording rate in the test pattern corresponds to an intermediate tone.

6. A print control apparatus in accordance with claim 1, wherein said print head is capable of ejecting multiple inks of different hues, and

the test pattern includes the first dot and the second dot, which are formed in different hues and partially overlap each other.

7. A print control apparatus in accordance with claim 1, wherein said print head is capable of ejecting multiple inks of different hues,

said driving module drives said print head in both a forward pass and a backward pass of the main scan,

the first dot is a forward dot created in the forward pass of the main scan of said print head,

the second dot is a backward dot created in the backward pass of the main scan of said print head, and

the test pattern includes the forward dot and the backward dot, both of which are created with multiple color inks.

8. A print control apparatus in accordance with claim 1, wherein a spatial frequency of a variation in density in the main scanning direction in the test pattern ranges 0.4 to 2.0 cycles/mm.

9. A print control apparatus in accordance with claim 1, wherein said test pattern data generation module comprises:

a memory that stores tone data of the test pattern; and

a print data generation module that causes the tone data to be subjected to a halftoning process with a diffusion matrix, which diffuses a tone error arising in a pixel of interest currently processed to peripheral non-processed pixels with preset weights, and thereby generates print data used for printing the test pattern.

10. A print control apparatus in accordance with claim 9, wherein the diffusion matrix sets either of zero and a negative value to an element corresponding to a pixel, which is expected to be in a state of dot formation identical with that in the pixel of interest.

17. A recording medium in which a program is recorded in a computer readable manner, said program controlling a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head,

said program causing a computer to actualize functions of a print control apparatus in accordance with any one of claims 1 to 13.

18. A recording medium in which print data is recorded in a computer readable manner, said print data being used to control a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head,

said print data being used to print a test pattern, which is applied to a print control apparatus in accordance with any one of claims 1 to 13.

11. A print control apparatus that supplies print data to a printing device, which creates dots and thereby carries out printing,

said printing device comprising:

a print head having multiple nozzles, from which ink is ejected;

a scanning module that carries out main scan and sub-scan of said print head; and

a driving module that drives said print head during each scan and causes at least two different types of dots, a first dot and a second dot, to be created at different timings in respective pixels,

said print control apparatus comprising;

a test pattern data generation module that generates test pattern data used for printing a predetermined test pattern,

wherein the test pattern is a patch pattern, in which dots are created at a preset recording rate in a predetermined area and substantially equal numbers of the first dot and the second dot are created with a substantially equivalent dispersibility over a practically whole area.

13. A print control apparatus in accordance with claim 12, wherein said print control module, in response to the setting of the test pattern mode, carries out the main scan and the sub-scan in a condition that attains a higher visual recognizability with regard to positional misalignment of dots than that in the other print modes.

20. A print control apparatus in accordance with claim 19, wherein the preset recording rate in the test pattern corresponds to an intermediate tone.

21. A print control apparatus in accordance with claim 19, wherein the first dot and the second dot are created with nozzles having different positions in the main scanning direction.

22. A print control apparatus in accordance with claim 19, wherein said driving module drives said print head in both a forward pass and a backward pass of the main scan,

the first dot is a forward dot created in the forward pass, and the second dot is a backward dot created in the backward pass.

23. A print control apparatus in accordance with claim 19, wherein said print head is capable of ejecting multiple inks of different hues, and

the test pattern includes the first dot and the second dot, which are created with inks of different hues.

24. A print control apparatus in accordance with claim 19, wherein said print head is capable of ejecting multiple inks of different hues,

said driving module drives said print head in both a forward pass and a backward pass of the main scan,

the first dot is a forward dot created in the forward pass of the main scan of said print head,

the second dot is a backward dot created in the backward pass of the main scan of said print head, and

the test pattern includes the forward dot and the backward dot, both of which are created with multiple color inks.

25. A print control apparatus in accordance with claim 19, wherein a spatial frequency of appearance of the first area and the second area in the main scanning direction ranges 0.4 to 2.0 cycles/mm.

26. A print control apparatus in accordance with claim 19, said print control apparatus further comprising:

a printing condition input module that inputs a printing condition,

wherein said test pattern data generation module generates different test pattern data according to the input printing condition.

27. A print control apparatus in accordance with claim 19, wherein said test pattern data generation module comprises:

a memory that stores tone data of the test pattern; and

a print data generation module that causes the tone data to be subjected to a halftoning process with a diffusion matrix, which diffuses a tone error arising in a pixel of interest currently processed to peripheral non-processed pixels with preset weights, and thereby generates print data used for printing the test pattern.

28. A print control apparatus in accordance with claim 27, wherein the diffusion matrix sets a greatest value to elements corresponding to non-processed pixels adjoining to the pixel of interest in the main scanning direction and in the sub-scanning direction.

29. A print control apparatus in accordance with claim 27, wherein the diffusion matrix sets either of zero and a negative value to an element corresponding to a pixel, which is expected to be in a state of dot formation identical with that in the pixel of interest.

30. A print control apparatus in accordance with claim 27, wherein the diffusion matrix sets either of a maximum value and a minimum value to a middle element among three consecutive elements aligned in the main scanning direction.

43. A recording medium in which a diffusion matrix is recorded in a computer readable manner, said diffusion matrix being used to control a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head,

said diffusion matrix being used to generate a test pattern, which is applied to a print control apparatus in accordance with any one of claims 28 to 30.

12. A print control apparatus that controls a printing device, said printing device comprising a print head with multiple nozzles, from which ink is ejected, and creating dots on a printing medium while carrying out main scan and sub-scan of said print head relative to the printing medium, said print control apparatus comprising:

a print mode setting module that selects and sets a print mode to be used for printing, among a plurality of print modes including a test pattern mode, which is used to print a predetermined test pattern; and

a print control module that, in response to setting of the test pattern mode, controls said printing device to carry out the main scan and the sub-scan in a different condition from that in the other print modes.

14. A method of adjusting misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) driving said print head at a plurality of preset different timings and thereby printing a plurality of test patterns to allow detection of the misalignment of recording positions between the first dot and the second dot;

(b) selecting an optimum test pattern among the plurality of printed test patterns; and

(c) setting a drive timing of said print head corresponding to the selected test pattern,

in said step (a), the test pattern being a patch pattern, in which dots are created at a preset recording rate in a predetermined area and a fraction of the first dot and the second dot adjoining to each other in either of a main scanning direction and a sub-scanning direction is significantly greater than a fraction of the first dots or the second dots adjoining to each other.

15. A method of adjusting misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) driving said print head at a plurality of preset different timings and thereby printing a plurality of test patterns to allow detection of the misalignment of recording positions between the first dot and the second dot;

(b) selecting an optimum test pattern among the plurality of printed test patterns; and

(c) setting a drive timing of said print head corresponding to the selected test pattern,

in said step (a), the test pattern being a patch pattern, in which dots are created at a preset recording rate in a predetermined area and substantially equal numbers of the first dot and the second dot are created with a substantially equivalent dispersibility over a practically whole area.

16. A method of adjusting misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) inputting an instruction that specifies either of execution and non-execution of adjustment;

(b) in response to the instruction that specifies execution of the adjustment, printing a predetermined test pattern, which is formed by main scan and sub-scan in a condition different from that in a standard print mode, at a plurality of preset different drive timings of said print head;

(c) selecting an optimum test pattern among the plurality of printed test patterns; and

(d) setting a drive timing of said print head corresponding to the selected test pattern.

19. A print control apparatus that supplies print data to a printing device, which creates dots and thereby carries out printing,

said printing device comprising:

a print head having multiple nozzles, from which ink is ejected;

a scanning module that carries out main scan and sub-scan of said print head; and

a driving module that drives said print head during each scan and causes at least two different types of dots, a first dot and a second dot, to be created at different timings in respective pixels,

said print control apparatus comprising;

a test pattern data generation module that generates test pattern data used for printing a predetermined test pattern,

wherein the test pattern is a patch pattern, in which substantially equal numbers of the first dot and the second dot are created at a preset recording rate in a predetermined area and a first area having a higher density of the first dot than a density of the second dot and a second area having a higher density of the second dot than a density of the first dot have a substantially equivalent size and are mixed in a main scanning direction and in a sub-scanning direction.

41. A recording medium in which a computer program is recorded in a computer readable manner, said computer program controlling a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head,

said computer program causing a computer to actualize functions of a print control apparatus in accordance with any one of claims 19 to 31.

42. A recording medium in which print data is recorded in a computer readable manner, said print data being used to control a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head,

said print data being used to print a test pattern, which is applied to a print control apparatus in accordance with any one of claims 19 to 31.

31. A print control apparatus that controls a printing device, said printing device comprising a print head with multiple nozzles, from which ink is ejected, and creating dots on a printing medium while carrying out main scan and sub-scan of said print head relative to the printing medium, said print control apparatus comprising:

a print mode setting module that selects and sets a print mode to be used for printing, among a plurality of print modes including a test pattern mode, which is used to print a predetermined test pattern; and

a print control module that, in response to setting of the test pattern mode, causes video data of the test pattern to be subjected to a halftoning process in a condition proper to the test pattern, thus generating print data to be supplied to said printing device.

32. A print control apparatus in accordance with claim 31, wherein the plurality of print modes include a text print mode for printing letters and a natural image print mode for printing a natural image, and

said print control module carries out different halftoning processes corresponding to the respective print modes.

33. A test pattern used to adjust misalignment of recording positions between a first dot and a second dot created at different timings,

said test pattern being a patch pattern, in which substantially equal numbers of the first dot and the second dot are created at a preset recording rate in a predetermined area and a first area having a higher density of the first dot than a density of the second dot and a second area having a higher density of the second dot than a density of the first dot are mixed in a two-dimensional manner.

35. A method in accordance with claim 34, wherein the diffusion matrix used in said step (c) sets a greatest value to elements corresponding to non-processed pixels adjoining to the pixel of interest in the main scanning direction and in the sub-scanning direction.

36. A method in accordance with claim 34, wherein the diffusion matrix used in said step (c) sets either of zero and a negative value to an element corresponding to a pixel, which is expected to be in a state of dot formation identical with that in the pixel of interest.

37. A method in accordance with claim 34, wherein the diffusion matrix used in said step (c) sets either of a maximum value and a minimum value to a middle element among three consecutive elements aligned in the main scanning direction.

39. A method in accordance with claim 38, wherein said print device is capable of creating N different types of dots (where N is an integer of not less than 2),

said step (a) comprises the step of printing the test patterns with regard to M different types of dots (where M is an integer of not less than 2 and not greater than N) among the N different types of dots,

said step (b) comprises the step of selecting the optimum test patterns with regard to the M different types of dots, and

said step (c) comprises the step of determining the drive timing of said print head according to a predetermined function based on M drive timings of said print head corresponding to the selected M test patterns.

34. A method of generating test pattern data, which is used to adjust misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) setting video data of a patched test pattern having a preset area;

(b) specifying a dot recording method; and

(c) carrying out a halftoning process with a diffusion matrix, which diffuses a tone error arising in a pixel of interest currently processed to peripheral non-processed pixels with preset weights,

wherein the diffusion matrix causes a first area having a higher density of the first dot than a density of the second dot and a second area having a higher density of the second dot than a density of the first dot to be mixed in a main scanning direction and in a sub-scanning direction.

38. A method of adjusting misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) driving said print head at a plurality of preset different timings and thereby printing a plurality of test patterns to allow detection of the misalignment of recording positions between the first dot and the second dot;

(b) selecting an optimum test pattern among the plurality of printed test patterns; and

(c) setting a drive timing of said print head corresponding to the selected test pattern,

in said step (a), the test pattern being a patch pattern, in which substantially equal numbers of the first dot and the second dot are created at a preset recording rate in a predetermined area and a first area having a higher density of the first dot than a density of the second dot and a second area having a higher density of the second dot than a density of the first dot are mixed in a main scanning direction and in a sub-scanning direction.

40. A method of adjusting misalignment of recording positions between a first dot and a second dot, which are created at different timings by a printing device that comprises a print head having multiple nozzles for ejecting ink and creates dots on a printing medium with said print head, said method comprising the steps of:

(a) inputting an instruction that specifies either of execution and non-execution of adjustment;

(b) in response to the instruction that specifies execution of the adjustment, printing a test pattern at a plurality of preset different drive timings of said print head, the test pattern being obtained by causing video data of the test pattern to be subjected to a halftoning process in a condition proper to the test pattern;

(c) selecting an optimum test pattern among the plurality of printed test patterns; and

(d) setting a drive timing of said print head corresponding to the selected test pattern.