JP2001138502A - Printing that matches the sub-scan feed amount between the middle and the end of the print medium - Google Patents

Abstract

(57) Abstract: Printing is performed in the vicinity of the upper end or the lower end of a print medium by using a print method consistent with a specific print method adopted in an intermediate area of a print medium. SOLUTION: In accordance with a first printing method, printing is performed in an intermediate portion of a printing execution area on a printing medium, and at least one of a vicinity of a leading end and a vicinity of a trailing end is compared with the first printing method. Printing is performed according to the second recording method with a small scanning feed amount. The sub-scan feed amount in the first recording method is L1 · D (L1 is an integer),
The sub-scan feed amount in the second recording method is represented by L2 · D
Is an integer). A combination of a plurality of different values is used as the integer L2. The remainder array obtained by dividing the accumulated value ΣL1 of the integer L1 by the integer k at each sub-scan feed, and the remainder array obtained by dividing the accumulated value ΣL2 of the integer L2 at each sub-scan feed. And the arrays of the values of the integers L1 and L2 are determined such that are equal to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing technique for performing printing by discharging ink droplets.

[0002]

2. Description of the Related Art In recent years, as an output device of a computer,
Ink jet printers that eject ink from a head are widely used. In the ink jet printer, various devices have been devised for the dot recording method in order to improve the image quality. Here, the “dot recording method” includes various parameters such as the number of nozzles to be used and the amount of sub-scan feed, and how the raster line (main scan line) on the print medium and the pixel position thereover are determined. Means a printing method that specifies whether to record in an appropriate order. In general, even if the same print head is used, it is possible to improve the image quality by devising the parameters of the dot recording method. Hereinafter, the “dot recording method” is also referred to as a “printing method”.

[0003]

By the way, in order to expand the printable area near the upper end and the lower end of the print medium, printing is performed by a recording method different from the print method used in the intermediate area of the print medium. May be performed.
At this time, it is preferable that the printing method adopted in the vicinity of the upper end and the lower end of the printing medium is consistent with the recording method adopted in the middle area of the printing medium.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and uses a recording method that is consistent with a specific recording method adopted in an intermediate area of a print medium to print the print medium. It is an object of the present invention to provide a technique for performing printing near the upper end or near the lower end.

[0005]

In order to solve at least a part of the above-mentioned problems, according to the present invention, the pitch along the sub-scanning direction is kD (k is an integer of 2 or more; Is a dot pitch corresponding to the printing resolution in the sub-scanning direction), and is supplied to a printing unit that performs printing by forming ink dots on a printing medium using a print head having a plurality of nozzles arranged so as to have a printing resolution. Generate print data to be printed. As the print data, printing is performed according to the first printing method in an intermediate portion of the print execution area on the print medium, and the print data is printed in at least one of the vicinity of the front end and the rear end of the print execution area. Print data for executing printing in accordance with the second recording method having a smaller sub-scan feed amount than the method is generated.
The sub-scan feed amount in the first recording method is represented by L1 · D (L1
Is an integer), and when the sub-scan feed amount in the second printing method is L2 · D (L2 is an integer), the second printing method uses a combination of a plurality of different values as the integer L2.
In the first recording method, the accumulated value of the integer L1ＬL1
And the remainder array obtained by dividing the accumulated value ΣL2 of the integer L2 by the integer k at each sub-scan feed in the second printing method. , Are equal to each other, the arrays of values of the integers L1 and L2 are determined.

[0006] For example, such a surplus arrangement indicates what position of the main scanning line is to be recorded. In the present invention, since the respective sub-scan feed amounts are determined so that the remaining arrays are equal to each other in the first and second printing methods, the transition of the position of the main scanning line to be printed is changed. Can be made the same in the first and second recording methods. Therefore, according to the present invention, it is possible to execute printing in the vicinity of the end of the print medium by using a print method that is consistent with the specific print method adopted in the intermediate area of the print medium.

Such a recording method in the vicinity of the end of the recording execution area can be adopted in both the vicinity of the front end and the vicinity of the rear end.

It is preferable that the integers L1 and L2 are determined so that continuous main scanning lines are not sequentially recorded in the continuous main scanning. In this way, it is possible to prevent the image quality from changing at the position where the continuity is interrupted in both the middle portion and the vicinity of the end of the print medium.

As specific embodiments of the present invention, a printing control method and method, a printing apparatus and a printing method, a computer program for realizing the functions of these apparatuses or methods, and a computer readout recording the computer program are provided. It can take various forms, such as a possible recording medium, a data signal including its computer program and embodied in a carrier wave.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on examples in the following order. A. Overall configuration of device: Basic conditions of normal recording method: Concept of upper end processing and lower end processing: Specific Example of Recording Method in Embodiment: Modified example

A. FIG. 1 is a block diagram showing the configuration of a printing system as an embodiment of the present invention. The printing system includes a computer 90 as a print control device, a color printer 22 as a printing unit,
A scanner 12 as an image reading device. Note that the printer 22 and the computer 90 can be called a “printing device” in a broad sense.

In the computer 90, the application program 9 is executed under a predetermined operating system.
5 is working. A video driver 91 and a printer driver 96 are incorporated in the operating system, and print data FNL to be transferred to the printer 22 is output from the application program 95 via these drivers. An application program 95 for retouching an image reads an image from the scanner 12 and displays the image on the CRT 21 via the video driver 91 while performing predetermined processing on the image. Data ORG supplied from the scanner 12 is original color image data ORG read from a color original and composed of three color components of red (R), green (G), and blue (B).

When the application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image data from the application program 95 and converts it into print data FNL to be supplied to the printer 22. In the example shown in FIG. 1, the resolution conversion module 97, the color conversion module 98, and the halftone module 99 are provided inside the printer driver 96.
, A rasterizer 100, a color conversion table LUT,
Is provided.

The resolution conversion module 97 serves to convert the resolution of the color image data handled by the application program 95 (ie, the number of pixels per unit length) into a resolution that can be handled by the printer driver 96. The image data whose resolution has been converted in this way is still image information consisting of three colors of RGB. The color conversion module 98 converts the RGB image data into multi-tone data of a plurality of ink colors that can be used by the printer 22 for each pixel while referring to the color conversion table LUT.

The multi-tone data after the color conversion is, for example, 25
It has six gradation values. The halftone module 99 disperses and forms the ink dots,
The printer 22 executes a halftone process for expressing this gradation value. The halftone-processed image data is rearranged by the rasterizer 100 in the order of data to be transferred to the printer 22, and the final print data FNL
Is output as The print data FNL includes
Data on the sub-scan feed amount is also included. That is, the print data FNL includes raster data indicating the dot recording state during each main scan, and data indicating the sub-scan feed amount. In the present embodiment, the printer 22 only plays a role of forming ink dots according to the print data FNL, and does not perform image processing. However, a part of the processing performed in the printer driver 96 may be performed by the printer 22.

The printer driver 96 corresponds to a program for realizing a function of generating print data FNL. A program for realizing the function of the printer driver 96 is supplied in a form recorded on a computer-readable recording medium. Examples of such a recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, and an internal storage device of a computer (such as a RAM or a ROM). Various computer-readable media, such as memory and external storage, can be used.

FIG. 2 is a schematic configuration diagram of the printer 22. The printer 22 drives a paper feed motor 23 to convey the paper P, a carriage motor 24 to reciprocate the carriage 31 in the axial direction of the platen 26, and drives a print head 28 mounted on the carriage 31. It comprises a mechanism for discharging ink and forming ink dots, and a control circuit 40 for exchanging signals with the paper feed motor 23, carriage motor 24, print head 28 and operation panel 32.

A mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 is provided in parallel with the axis of the platen 26, and an endless mechanism is provided between a carriage shaft 24 and a slide shaft 34 for slidably holding the carriage 31. And a position detecting sensor 39 for detecting the origin position of the carriage 31.

FIG. 3 is an explanatory diagram showing the nozzle arrangement on the lower surface of the print head 28. As shown in FIG. The lower surface of the print head 28, the black ink nozzle group K _D for ejecting black ink, a dark cyan ink nozzle group C _D for ejecting dark cyan ink, for ejecting light cyan ink light cyan yellow ink for ejecting the ink nozzle group C _L, and dark magenta ink nozzle group M _D for ejecting dark magenta ink, light magenta ink nozzle group M _L for ejecting light magenta ink, a yellow ink a nozzle group Y _D is formed.

The capital letter of the first alphabet in the code indicating each nozzle group means an ink color.
The suffix “ _D ” means that the ink has a relatively high density, and the suffix “ _L ” means that the ink has a relatively low density.

The plurality of nozzles of each nozzle group are arranged at a constant nozzle pitch kD along the sub-scanning direction SS. Here, k is an integer, and D is a pitch (“dot pitch”) corresponding to the print resolution in the sub-scanning direction.
). In this specification, it is also referred to as “the nozzle pitch is k dots”. The unit [dot] at this time is
It means the dot pitch of the printing resolution. Similarly, the unit of [dot] is used for the sub-scan feed amount.

Each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets. When printing, the carriage 3
1 (FIG. 2), ink droplets are ejected from each nozzle while the print head 28 moves in the main scanning direction MS.

In the printer 22 having the hardware configuration described above, the carriage 31 is reciprocated by the carriage motor 24 while the paper P is conveyed by the paper feed motor 23, and at the same time, the ink ejection heads 61 to 66 of the print head 28 are moved. Are driven to discharge ink droplets of each color to form ink dots and form multi-color and multi-tone images on the paper P.

B. Basic conditions of normal recording method: Before describing the details of the recording method used in the embodiment of the present invention, first, basic conditions of the normal recording method will be described below. Note that, in this specification, “recording method” and “printing method” are synonyms.

FIG. 4 is an explanatory diagram showing basic conditions of a normal dot recording system. FIG. 4A shows an example of sub-scan feed when four nozzles are used, and FIG. 4B shows parameters of the dot recording method. In FIG. 4A, solid-line circles including numbers indicate the positions of the four nozzles in the sub-scanning direction in each pass. Here, “pass” means one main scan. Numbers 0 to 3 in the circles indicate nozzle numbers. The positions of the four nozzles are sent in the sub-scanning direction each time one main scan is completed. However, actually, the feed in the sub-scanning direction is realized by moving the paper by the paper feed motor 23 (FIG. 2).

As shown at the left end of FIG. 4A, in this example, the sub-scan feed amount L is a constant value of 4 dots. Therefore,
Each time the sub-scan feed is performed, the positions of the four nozzles shift by four dots in the sub-scan direction. Each nozzle targets all dot positions (also referred to as “pixel positions”) on each raster line during one main scan.
In this specification, the total number of main scans performed on each raster line (also referred to as “main scan line”) is referred to as “scan repeat count s”.

At the right end of FIG. 4A, nozzle numbers for recording dots on each raster line are shown. In the raster line drawn by a broken line extending rightward (main scanning direction) from a circle indicating the position of the nozzle in the sub-scanning direction,
Since at least one of the upper and lower raster lines cannot be printed, dot printing is actually prohibited. On the other hand, a raster line drawn by a solid line extending in the main scanning direction is a range in which both the preceding and succeeding raster lines can be recorded by dots. The range in which printing can be actually performed in this manner is hereinafter referred to as an effective printing range (or “effective printing range”, “print execution area”, “recording execution area”).

FIG. 4B shows various parameters relating to the dot recording system. The parameters of the dot recording method include the nozzle pitch k [dot], the number of used nozzles N [number], the number of scan repetitions s, the effective number of nozzles Neff [number], and the sub-scan feed amount L [dot].
And are included.

In the example of FIG. 4, the nozzle pitch k is 3 dots. The number N of used nozzles is four. The number of used nozzles N is the number of nozzles actually used among a plurality of mounted nozzles. The number of scan repetitions s means that s main scans are performed on each raster line. For example, when the number of scan repetitions s is 2, two main scans are performed on each raster line. At this time, usually, dots are formed intermittently every other dot in one main scan.
In the case of FIG. 4, the number of scan repetitions s is one. The effective nozzle number Neff is a value obtained by dividing the used nozzle number N by the number of scan repetitions s. This effective nozzle number Nef
f can be considered to indicate the net number of raster lines for which dot recording is completed in one main scan.

The table of FIG. 4B shows the sub-scan feed amount L in each pass, the total value ΔL thereof, and the nozzle offset F. Here, the offset F is the position of the nozzle in each subsequent pass, assuming that the periodic position of the nozzle in the first pass 1 (the position every four dots in FIG. 4) is the reference position where the offset is 0. Is a value indicating how many dots are apart from the reference position in the sub-scanning direction. For example, as shown in FIG. 4A, after pass 1, the nozzle position moves in the sub-scanning direction by the sub-scan feed amount L (4 dots). On the other hand, the nozzle pitch k is 3 dots. Therefore, the nozzle offset F in pass 2 is 1 (see FIG. 4A). Similarly, pass 3
Is shifted from the initial position by ΔL = 8 dots, and the offset F thereof is 2. The position of the nozzle in pass 4 has moved by ΔL = 12 dots from the initial position, and its offset F is zero. In pass 4 after the three sub-scan feeds, the nozzle offset F returns to 0. Therefore, the three sub-scans are regarded as one cycle, and this cycle is repeated so that all the dots on the raster lines in the effective recording range are erased. Can be recorded.

As can be seen from the example of FIG. 4, when the nozzle position is located at a position away from the initial position by an integral multiple of the nozzle pitch k, the offset F is zero. The offset F is given by the remainder (ΔL)% k obtained by dividing the total value ΔL of the sub-scan feed amount L by the nozzle pitch k. here,
“%” Is an operator indicating that the remainder of the division is taken.
If the initial position of the nozzle is considered to be a periodic position, the offset F can be considered to indicate the amount of phase shift from the initial position of the nozzle.

When the number of scan repetitions s is 1, it is necessary to satisfy the following conditions in order to avoid missing or overlapping raster lines to be recorded in the effective recording range.

Condition c1: The number of sub-scan feeds per cycle is equal to the nozzle pitch k.

Condition c2: The nozzle offset F after each sub-scan feed in one cycle takes a different value in the range of 0 to (k-1).

Condition c3: Average feed amount of sub-scan (ΣL /
k) is equal to the number N of used nozzles. In other words, the total value ΔL of the sub-scan feed amount L per cycle is equal to a value (N × k) obtained by multiplying the number of used nozzles N by the nozzle pitch k.

Each of the above conditions can be understood by considering the following. (K-1) between adjacent nozzles
Since there are three raster lines, it is necessary to perform recording on these (k-1) raster lines in one cycle and return to the nozzle reference position (offset F is zero) in one cycle. The number of scanning feeds is k. If the number of sub-scan feeds in one cycle is less than k times, the raster lines to be printed are missing, while if the number of sub-scan feeds in one cycle is more than k times, the raster lines to be printed overlap. Therefore, the above first condition c1 is satisfied.

When the number of sub-scan feeds per cycle is k,
The value of the offset F after each sub-scan feed is 0 to (k−
Only when the values in the range 1) are different from each other, missing or overlapping raster lines are eliminated. Therefore, the above second condition c2 is satisfied.

If the above first and second conditions are satisfied, 1
During the cycle, each of the N nozzles records k raster lines. Therefore, in one cycle, N × k raster lines are recorded. on the other hand,
If the above third condition c3 is satisfied, as shown in FIG. 4A, the nozzle position after one cycle (after k sub-scan feeds) is shifted by N × k raster lines from the initial nozzle position. Come to a remote location. Therefore, the first to third conditions c
By satisfying 1 to c3, in the range of these N × k raster lines, missing or overlapping of the recorded raster lines can be eliminated.

The example of the recording method shown in FIG. 4 has a feature that "continuous raster lines are successively recorded in continuous main scanning". Specifically, as shown by an arrow A, for example, the fourth to seventh raster lines are sequentially recorded in pass 1 to pass 4. The offset F at the bottom of the table in FIG. 4B corresponds to such continuity. That is, the offset F
Are sequentially increased one by one from 0, 1, 2,
This corresponds to the phenomenon that “continuous raster lines in sequential main scanning are sequentially recorded”.

By the way, in a recording method in which continuous raster lines are sequentially recorded in continuous main scanning, a sub-scanning feed error may increase at a position where the continuity is interrupted. For example, the seventh raster line is recorded in pass 4 while the eighth raster line is recorded in pass 2, so that the seventh and eighth raster lines are subject to recording in a continuous main scan. It is not, and the continuity is interrupted here. Two sub-scan feeds are performed between pass 2 where the eighth raster line is printed and pass 4 where the seventh raster line is printed. On the other hand, only one sub-scan feed is performed between two adjacent raster lines between the fourth and seventh lines. As the sub-scan feed is performed, the error of the sub-scan feed is accumulated, so that the accumulated error due to two sub-scan feeds is larger than the error of one sub-scan feed. As a result, the actual spacing between the seventh and eighth raster lines may be different from the spacing between each of the fourth through seventh adjacent raster lines. As a result, between the seventh and eighth raster lines, a streak-like image degradation part along the main scanning direction called "banding" may occur.

The above-mentioned tendency becomes more remarkable as the difference in the number of passes for printing raster lines before and after the position where continuity is interrupted increases. Therefore, as a recording method,
In the continuous main scanning, it is preferable that the sub-scan feed amount is determined so that continuous raster lines are not sequentially recorded. In particular, it is preferable that the determination is made so that continuous raster lines are not sequentially recorded in three or more consecutive main scans. Further, it is preferable that the determination is made so that continuous raster lines are not sequentially recorded in k or more continuous main scans (k is a nozzle pitch).

FIG. 5 is an explanatory diagram showing the basic conditions of the dot recording system when the number of scan repetitions s is 2 or more. When the number of scan repetitions s is 2 or more, s main scans are performed on the same raster line. Hereinafter, a dot recording method in which the number of scan repetitions s is 2 or more is referred to as an “overlap method”.

The dot recording method shown in FIG.
In the parameters of the dot recording method shown in FIG. 5, the number of scan repetitions s and the sub-scan feed amount L are changed.
As can be seen from FIG. 5A, the sub-scan feed amount L in the dot recording method of FIG. 5 is a constant value of 2 dots. However, in FIG. 5A, the positions of the nozzles in the even-numbered passes are indicated by diamonds. Normally, as shown at the right end of FIG. 5A, the dot position printed in the even-numbered pass is shifted by one dot in the main scanning direction from the dot position printed in the odd-numbered pass. . Therefore, a plurality of dots on the same raster line are intermittently recorded by two different nozzles. For example,
The uppermost raster line in the effective recording range is intermittently printed every other dot by the second nozzle in pass 2 and then intermittently printed every other dot by the zeroth nozzle in pass 5. . In this overlap method, each nozzle prints one dot during one main scan (s-
1) The nozzle is driven at intermittent timing so as to prohibit dot recording.

As described above, the overlap method in which the intermittent pixel positions on the raster line are to be recorded at the time of each main scan is called "intermittent overlap method". Instead of setting intermittent pixel positions as recording targets, all pixel positions on a raster line may be set as recording targets at each main scan. That is, when s main scanning is performed on one raster line, overlapping of dots may be allowed at the same pixel position. Such an overlap method,
This is referred to as “overlapping overlap method” or “complete overlap method”.

In the intermittent overlap method, since the positions of a plurality of nozzles that record the same raster line in the main scanning direction need only be shifted from each other, the actual shift amount in the main scanning direction during each main scan is: Various things other than those shown in FIG. For example, it is also possible to record dots at positions indicated by circles in pass 2 without shifting in the main scanning direction, and to record dots in positions indicated by diamonds in pass 5 by shifting in the main scanning direction. It is.

The value of the offset F of each path during one cycle is shown at the bottom of the table of FIG. 5B. One cycle includes six passes, and the offset F in each pass from pass 2 to pass 7 includes a value in the range of 0 to 2 twice. Also, 3 from pass 2 to pass 4
The change in the offset F in one pass is equal to the change in the offset F in three passes from pass 5 to pass 7. As shown at the left end of FIG.
One pass can be partitioned into two sets of three small cycles of three. At this time, one cycle corresponds to a small cycle of s.
Complete by repeating it.

In general, when the number of scan repetitions s is an integer of 2 or more, the first to third conditions c1 to c3 described above are used.
c3 is rewritten as the following conditions c1 ′ to c3 ′.

Condition c1 ′: The number of sub-scan feeds in one cycle is equal to the value (k × s) obtained by multiplying the nozzle pitch k by the number of scan repetitions s.

Condition c2 ': The nozzle offset F after each sub-scan feed in one cycle is a value in the range of 0 to (k-1), and each value is repeated s times.

Condition c3 ′: average feed amount of sub-scan ΔL /
(K × s)} is equal to the effective nozzle number Neff (= N / s). In other words, the sub-scan feed amount L per cycle
Is equal to the value {Neff × (k × s)} obtained by multiplying the number of effective nozzles Neff by the number of sub-scan feeds (k × s).

The above conditions c1 'to c3' hold even when the number of scan repetitions s is 1. Therefore, condition c
The conditions 1 ′ to c3 ′ are generally satisfied for the dot recording method regardless of the value of the scan repetition number s. That is, if the above three conditions c1 ′ to c3 ′ are satisfied, it is possible to prevent dots to be recorded from missing or unnecessary duplication in the effective recording range. However,
In the case where the intermittent overlap method is adopted, a condition that the recording positions of the nozzles that record the same raster line are shifted from each other in the main scanning direction is also necessary. In the case of using the overlapping overlap method, the above condition c
It suffices that 1 ′ to c3 ′ are satisfied, and all pixel positions are to be recorded in each pass.

The recording method shown in FIG. 5 has a feature that "continuous raster lines are successively recorded in successive main scanning", similarly to the recording method shown in FIG. Specifically, for example, as indicated by an arrow B, the eighth or fifth raster line is sequentially recorded in the passes 4 to 7. The arrangement of the offsets F in the lower part of the table in FIG. 5B also corresponds to such continuity.
That is, the value of the offset F is sequentially reduced by 2, 1, 0, and one by one.

C. Concept of upper end processing and lower end processing: FIG.
FIG. 8 is an explanatory diagram showing a concept of applying a recording method in the embodiment. A print execution area PA in which printing is actually executed is set on the printing paper P. The recording method for the intermediate area processing is applied to the intermediate area of the print execution area PA. The recording method for the intermediate area processing is based on the conditions c1 ′ to c1 described above.
This is a recording method that satisfies 3 ′ and has no missing dots or unnecessary duplication in the dots to be recorded. In the vicinity of the upper end and the lower end of the print execution area PA, recording methods for upper end processing and lower end processing are respectively applied. In this specification, the special printing process near the upper end of the printing paper is referred to as “upper process”, and the special printing process near the lower end of the printing paper is referred to as “lower process”.

FIG. 7 is an explanatory diagram showing the concept of the recording method of the upper end processing of printing paper. Here, for convenience of explanation, an example in which the number of scan repetitions s is 1 will be mainly described.

As shown in FIG. 4 described above, there is a range (non-printable range) where dot printing cannot be performed effectively near the upper end of the printing paper. Therefore, in the upper end processing, the non-recordable range is reduced and the effective recording range is increased by setting the sub-scan feed amount to a value smaller than the feed amount in the intermediate area process. More specifically, in the upper end processing shown in FIG. 7A, the sub-scan feed amount L is set to 2 dots, and this value is set to the sub-scan feed amount L (= 4 dots). As a result, it is understood that the effective recording range is increased by four raster lines as compared with the case of FIG.

In the fourth pass of FIG. 7A, the 0th nozzle and the 1st nozzle do not execute dot printing. The reason for this is that the raster line to be printed by the 0th nozzle and the 1st nozzle in the fourth pass has already been the print target by the 2nd nozzle and the 3rd nozzle in the first pass.

FIG. 7B shows scanning parameters in the upper end processing. These scanning parameters do not satisfy the above-described conditions c1 ′ to c3 ′ in the normal printing method. The reason for this is that, as shown in FIG. 7A, in the upper end processing, overlapping of raster lines to be recorded by the used nozzles is allowed.

As can be understood from FIG. 7A,
This upper end process also has a feature that “continuous raster lines in successive main scans are sequentially recorded” as in the recording methods of FIGS. 4 and 5.

Generally, in the recording method adopted in the upper end processing, the sub-scan feed amount is set to a smaller value than in the recording method adopted in the middle area (excluding the vicinity of the upper end and the lower end) of the printing paper. This extends the effective recording range. Similarly, in the lower end processing, a printing method using a value having a smaller sub-scanning feed amount than the printing method adopted in the middle area of the printing paper is applied, thereby extending the effective printing range. Note that the concept of the lower end processing is almost the same as that of the upper end processing, and the description thereof is omitted here.

In some cases, irregular feeding (feeding using a plurality of different feed amounts) is employed in the intermediate area. Also, in the upper end processing and the lower end processing, it is possible to adopt the irregular feeding. In these cases, the average value of the sub-scan feed amount in the upper end process is set to a value smaller than the average value of the sub-scan feed amount in the intermediate region process. The same applies to the lower end processing. The phrase “the sub-scan feed amount is small” has a broad meaning including such a case.

D. Specific Example of Recording Method in Embodiment: FIG. 8 is an explanatory diagram showing scanning parameters in the intermediate area processing of the embodiment. This recording method uses a nozzle pitch k
Are 6 dots, the number N of used nozzles is 48, and the number of scan repetitions s is 2. Note that various recording methods in this specification can be applied to both unidirectional printing and bidirectional printing.

The table at the bottom of FIG. 8 shows parameters relating to 13 passes. As the sub-scan feed amount L, a combination of a plurality of different values is used. In addition,
A constant value can be used as the sub-scan feed amount. In the present specification, the sub-scan feed method using a plurality of different feed amounts in combination is referred to as “irregular feed”. The sub-scan feed method using a constant value as the feed amount is called "regular feed".

FIG. 9 shows the nozzle numbers assigned to printing on each raster line in each pass of the intermediate area processing. The “raster number” in FIG. 9 is a number from the upper end of the range in which any nozzle of the print head 28 can be positioned, including the non-recordable range (FIGS. 4 and 5). However, this raster number is based on the assumption that the upper end processing is not performed. The upper 253 raster lines are omitted for convenience of illustration.

As shown in the lower part of the table of FIG. 9, the value of the offset F is a repeating arrangement of {2, 5, 3, 1, 4, 0}. In the examples of FIGS. 4 and 5 described above, the value of the offset F increases or decreases by one, and in response to this, the phenomenon that “continuous raster lines are successively recorded in successive main scans”. Had occurred. On the other hand, in the recording method shown in FIG. 9, the offset F does not increase by one and does not decrease by one.
Therefore, continuous raster lines in continuous main scanning are not sequentially recorded.

FIG. 10 is an explanatory diagram showing scanning parameters in the lower end processing of this embodiment and nozzles for recording each raster line in each pass. As shown in the table of FIG. 10, pass-5 to pass0 correspond to the intermediate region processing, and pass1 and subsequent paths correspond to the lower end processing. The raster number is such that the lower end of the intermediate area is “0” and the upper end of the area where the lower end processing is performed is “1”. The actual lower end processing continues to pass 17, but in FIG. 10, five passes 13 to 17 are omitted for convenience. In FIG. 10,
A rectangle in which a nozzle number is described with an “x” mark means that the nozzle is not used.

As shown in the table at the top of FIG.
In this lower end process, the sub-scan feed amount L is {2, 3,
A 4,4,3,2} arrangement is used. They are,
This value is considerably smaller than the feed amount in the intermediate area processing. Further, the offset F in the lower end processing is ｛2, 5,
3, 1, 4, 0}, which is the same as that of the intermediate region processing.

In the lower end processing, since the arrangement of the offset F is the same as that of the intermediate area processing, the change of the raster line position recorded in the continuous main scanning is the same as that of the intermediate area processing. If the transition of the raster line position recorded in the continuous main scanning is different between the intermediate area processing and the lower end processing, the accumulated error of the sub-scan feed between adjacent raster lines will also be different. As a result,
There may be a difference in image quality between the intermediate processing area and the lower processing area. On the other hand, in the embodiment shown in FIG. 10, the change of the raster line position recorded in the continuous main scan is
Since the intermediate region processing and the lower end processing are the same, the possibility that such a difference in image quality occurs can be reduced.

In particular, in the embodiment shown in FIG. 10, in both the intermediate area processing and the lower end processing, the sub-scan feed amount is arranged so that continuous raster lines are not sequentially recorded in the continuous main scan. Has been determined. This is also a preferable recording method.

In the upper end processing, it is preferable that the arrangement of the sub-scan feed amounts is determined so that the arrangement of the offset F is the same as that of the intermediate area processing, as in the lower end processing shown in FIG. For example, the same feed amount as the sub-scan feed amount of the lower end process shown in FIG. 10 can be adopted in the upper end process. However, it is not always necessary to execute such sub-scan feed in both the upper end process and the lower end process, and such sub scan feed may be executed in one of the upper end process and the lower end process.

In the above embodiment, the irregular feed is adopted in the intermediate area processing. However, the regular feed can be adopted in the intermediate area processing. However, in this case,
In the upper end processing and lower end processing, irregular feed is adopted,
It is preferable to determine the arrangement of the sub-scan feed amounts so that the arrangement of the offsets F is the same as that of the intermediate area processing.

E. Modifications: The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are also possible. is there.

F1. Modification Example 1 The present invention is also applicable to a drum scan printer. In a drum scan printer, the drum rotation direction is the main scanning direction, and the carriage traveling direction is the sub scanning direction. In addition, the present invention can be applied not only to an ink jet printer but also to a printing apparatus that generally performs recording on the surface of a print medium using a print head having a plurality of nozzles. Such printing devices include, for example, facsimile machines and copy machines.

F2. Modification 2 In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. You may. For example, a part of the functions of the printer driver 96 (FIG. 1) may be executed by the control circuit 40 (FIG. 2) in the printer 22.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a printing system as one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a printer 22.

FIG. 3 is an explanatory diagram illustrating a nozzle arrangement on a lower surface of a print head.

FIG. 4 is an explanatory diagram showing basic conditions of a normal dot recording method.

FIG. 5 is an explanatory diagram showing basic conditions of an overlap recording method.

FIG. 6 is an explanatory diagram showing a concept of applying a recording method in the embodiment.

FIG. 7 is an explanatory diagram illustrating a concept of a recording method of upper end processing of printing paper.

FIG. 8 is an explanatory diagram showing scanning parameters in intermediate area processing according to the embodiment.

FIG. 9 is an explanatory diagram showing the numbers of nozzles in charge of printing on each raster line in each pass of the intermediate area processing.

FIG. 10 is an explanatory diagram showing scanning parameters in upper end processing of the present embodiment and nozzles for recording each raster line in each pass.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 ... Scanner 21 ... CRT 22 ... Color printer 23 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 31 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position detection sensor Reference Signs List 40 control circuit 61-66 ink discharge head 90 computer 91 video driver 95 application program 96 printer driver 97 resolution conversion module 98 color conversion module 99 halftone module 100 rasterizer

Claims (6)

[Claims] A pitch along a sub-scanning direction is kD (k
Is an integer of 2 or more, and D is a dot pitch corresponding to the print resolution in the sub-scanning direction). Printing is performed by forming ink dots on a print medium using a print head having a plurality of nozzles arranged to have A print control device for generating print data to be supplied to a printing unit to be performed, wherein the print control device prints the print data in an intermediate portion of a print execution area on the print medium according to a first printing method. And performing printing in at least one of the vicinity of the leading end and the trailing end of the printing execution area in accordance with the second printing method in which the sub-scan feed amount is smaller than that of the first printing method. Can be generated, and the sub-scan feed amount in the first recording method is set to L1 · D
(L1 is an integer) and the sub-scan feed amount in the second printing method is L2 · D (L2 is an integer). In the second printing method, a combination of a plurality of different values is used as the integer L2. And the accumulated value of the integer L1 ΣL in the first recording method.
1 and the remainder array obtained by dividing the integer k by the integer k at each sub-scan feed, and the accumulated value ΔL2 of the integer L2 by dividing by the integer k at each sub-scan feed by the second recording method. A print control apparatus, wherein the array of the values of the integers L1 and L2 is determined such that the remaining array is equal to the remaining array. 2. The printing apparatus according to claim 1, wherein the print data is printed in the vicinity of a front end of the recording execution area in accordance with the second recording method, and in a vicinity of a rear end of the recording execution area. Print data for performing printing in accordance with a third printing method having a smaller sub-scanning feed amount than the first printing method. The sub-scanning feed amount in the third printing method is represented by L3 · D.
When (L3 is an integer), the third recording method uses a combination of a plurality of different values as the integer L3, and the accumulated value of the integer L1 ΣL in the first recording method.
1 and the remainder array obtained by dividing the integer k at the time of each sub-scan feed, and the accumulated value ΣL3 of the integer L3 divided by the integer k at the time of each sub-scan feed in the third printing method. The printing apparatus, wherein the arrangement of the values of the integer L3 is determined so that the remaining arrangement is equal to the remaining arrangement. 3. The printing apparatus according to claim 1, wherein the integers L1 and L2 are determined such that continuous main scanning lines are not sequentially recorded in continuous main scanning. There is a printing device. 4. The pitch along the sub-scanning direction is kD (k
Is an integer of 2 or more, and D is a dot pitch corresponding to the print resolution in the sub-scanning direction). Printing is performed by forming ink dots on a print medium using a print head having a plurality of nozzles arranged to have A method for generating print data to be supplied to a printing unit to be performed, wherein the print data is printed according to a first printing method in an intermediate portion of a print execution area on the print medium as the print data. A step of generating print data for executing printing in accordance with a second printing method in which the sub-scan feed amount is smaller than the first printing method in at least one of the vicinity of the leading end and the vicinity of the trailing end of the area. The sub-scan feed amount in the first recording method is L1 · D
(L1 is an integer) and the sub-scan feed amount in the second printing method is L2 · D (L2 is an integer). In the second printing method, a combination of a plurality of different values is used as the integer L2. And the accumulated value of the integer L1 ΣL in the first recording method.
1 and the remainder array obtained by dividing the integer k by the integer k at each sub-scan feed, and the accumulated value ΔL2 of the integer L2 by dividing by the integer k at each sub-scan feed by the second recording method. And an array of values of the integers L1 and L2 is determined so that the remaining arrays are equal to each other. 5. A printing apparatus for performing printing on a printing medium while performing main scanning, wherein the printing unit supplies print data to the printing unit. The print unit comprises: a plurality of nozzles; a print head having a plurality of ejection drive elements for ejecting ink droplets from the plurality of nozzles; and at least one of the print medium and the print head. A main scanning drive unit that performs bidirectional main scanning by moving; a sub-scanning drive unit that performs sub-scanning by moving at least one of the print medium and the print head; and each ejection drive according to the print data And a head drive unit for supplying a drive signal to the element, wherein the plurality of nozzles have a pitch along the sub-scanning direction of k ·
D (k is an integer of 2 or more, and D is a dot pitch corresponding to the printing resolution in the sub-scanning direction).
Printing device. 6. The pitch along the sub-scanning direction is kD (k
Is an integer of 2 or more, and D is a dot pitch corresponding to the print resolution in the sub-scanning direction). Printing is performed by forming ink dots on a print medium using a print head having a plurality of nozzles arranged to have A computer-readable recording medium recording a computer program for causing a computer to generate print data to be supplied to a printing unit to be executed, wherein the computer program stores, as the print data, a recording execution area on the print medium. In the middle part of the above, printing is performed in accordance with the first recording method, and the sub-scan feed amount is smaller in at least one of the vicinity of the leading end and the trailing end of the recording execution area as compared with the first recording method. The computer has a function of generating print data for executing printing in accordance with a second recording method. It has a program for implementing the sub-scan feed amount in the first recording mode L1 · D
(L1 is an integer) and the sub-scan feed amount in the second printing method is L2 · D (L2 is an integer). In the second printing method, a combination of a plurality of different values is used as the integer L2. And the accumulated value of the integer L1 ΣL in the first recording method.
1 and the remainder array obtained by dividing the integer k by the integer k at each sub-scan feed, and the accumulated value ΔL2 of the integer L2 by dividing by the integer k at each sub-scan feed by the second recording method. A computer-readable recording medium, wherein an array of values of the integers L1 and L2 is determined so that an array of remainders is equal to each other.