JP2001341295A - Draft printing using nozzles for ejecting inks of the same hue as nozzles for ejecting the same kinds of ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance print speed greatly without lowering the image quality excessively. SOLUTION: In order to perform printing in a specified high speed print mode, print data being fed to a print section is generated such that each nozzle group of gray ink for each hue records a different main scanning line. According to the arrangement, the number of effective nozzles is increased and the print speed is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a technique for printing by forming dots on a print medium using a print head.

[0002]

2. Description of the Related Art As a printing apparatus that performs printing using a print head while scanning in a main scanning direction and a sub-scanning direction, there is an ink jet printer such as a serial scan printer or a drum scan printer. The ink jet printer forms characters and images on a print medium by discharging ink from a plurality of nozzles of a print head. The printing method includes a print mode for printing with high image quality and a high-speed draft print mode (high-speed print mode).

[0003]

In draft printing used for confirmation of image arrangement, etc., high image quality is not required, but high speed is very important. There has been a demand for performing printing at a higher speed than conventional draft printing.

[0004] The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technique capable of further improving the printing speed in a high-speed printing mode.

[0005]

In order to solve at least a part of the above-described problems, in a first configuration of the present invention, a print head that ejects a plurality of types of ink is scanned in a main scanning direction. A printing unit that generates print data to be supplied to the printing unit in order to perform printing using a printing unit that forms dots on a printing medium while performing printing, wherein the print heads have substantially the same hue. A plurality of the same hue nozzle groups that eject a plurality of the same hue inks different in at least one of the brightness and the saturation are provided, and the plurality of the same hue nozzle groups are arranged at positions shifted from each other along the sub-scanning direction. When performing printing in a predetermined high-speed print mode, the print control device sets the plurality of same hue nozzle groups to different main scan lines, and sets the same main scan line as a print target. No way, characterized in that it comprises a print data generating unit that generates the print data.

According to the first configuration, each of the nozzle groups ejecting inks having the same hue and different in at least one of lightness and saturation records different main scanning lines instead of the same main scanning line. The number of main scan lines that can be printed in one scan is greatly increased, and the printing speed is further improved. In addition, although different types of inks are used, recording is performed with the same hue, so that the deterioration of image quality is small.

The print data PD for draft printing
May be generated using a color conversion table for draft printing (FIG. 1).

In this case, the time required for generating the print data can be shortened, and the printing time can be shortened.

Further, halftone data generated for a print mode for printing with high image quality may be converted into halftone data for draft printing to generate print data PD for draft printing.

Thus, the present invention can be applied without preparing a color conversion table for draft printing.

Further, it is possible to generate print data PD for draft printing by converting print data PD generated for a print mode for printing with high image quality.

In this case, the present invention can be easily applied only by changing the firmware on the printer side.

Incidentally, the plurality of same hue nozzle groups may be arranged in a line along the sub-scanning direction.

By doing so, the print head can be made compact.

Further, when the main scanning lines to be recorded are in close contact with each other by applying the present invention, the sub-scan feed amount is set to an array of dots that can be formed by a plurality of the same hue nozzle groups in one main scan. May be set to the length value measured along the sub-scanning direction.

The print control device for generating the print data as described above may be realized by a computer configured as a device separate from a printing device having a printing unit.
Alternatively, it may be realized by a circuit in the printing device.

The present invention can be realized in various modes. For example, a printing method and a printing apparatus, a printing control method and a printing control apparatus, and a computer for realizing the functions of those methods or apparatuses are provided. The present invention can be realized in the form of a program, a recording medium on which the computer program is recorded, a data signal including the computer program and embodied in a carrier wave, and the like.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on examples in the following order. A. Device configuration: Basic conditions of recording method: Concept of multi-gradation by using a plurality of inks having different shades: Concept of print data and sub-scan feed in draft printing: Comparative Example and Example of Dot Recording Method in Draft Printing:

A. FIG. 1 is a block diagram showing the configuration of a printing system according to an embodiment of the present invention. The printing system includes a computer 90 as a print control device, a color printer 20 as a printing unit,
It has. Note that the combination of the color printer 20 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 PD to be transferred to the color printer 20 is output from the application program 95 via these drivers. The application program 95 performs a desired process on the image to be processed, and displays the image on the CRT 21 via the video driver 91.

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 PD to be supplied to the color printer 20. In the example shown in FIG. 1, a resolution conversion module 97, a color conversion module 98, a halftone module 99, a rasterizer 100, a color conversion table L
And a UT.

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 color printer 20 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 color printer 20 executes a halftone process for expressing this gradation value. The halftone-processed image data is sent to the color printer 2 by the rasterizer 100.
The data is rearranged in the order of data to be transferred to 0 and output as final print data PD. The print data PD
Contains raster data indicating the dot recording state during each main scan, and data indicating the sub-scan feed amount.

The printer driver 96 corresponds to a program for realizing the function of generating the print data PD. 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). memory)
Various computer-readable media such as an external storage device and the like can be used.

FIG. 2 is a schematic configuration diagram of the color printer 20. The color printer 20 includes a sub-scan feed mechanism that conveys the printing paper P in the sub-scan direction by a paper feed motor 22 and a main scan feed that reciprocates the carriage 30 in the axial direction (main scan direction) of the platen 26 by the carriage motor 24. Mechanism, a head drive mechanism that drives a print head unit 60 (also referred to as a “print head assembly”) mounted on the carriage 30 to control ink ejection and dot formation, and a paper feed motor 22 and a carriage motor 24, print head unit 60 and operation panel 32
And a control circuit 40 for exchanging signals with the control circuit 40. The control circuit 40 is connected to the computer 90 via the connector 56.

The sub-scan feed mechanism for conveying the printing paper P includes
A gear train (not shown) for transmitting the rotation of the paper feed motor 22 to the platen 26 and a paper transport roller (not shown) is provided. The main scanning feed mechanism for reciprocating the carriage 30 includes an endless drive belt 36 provided between the carriage motor 24 and a slide shaft 34 erected in parallel with the axis of the platen 26 and slidably holding the carriage 30. And a position sensor 39 for detecting the origin position of the carriage 30.

FIG. 3 is a block diagram showing the configuration of the color printer 20 with the control circuit 40 at the center. The control circuit 40 includes a CPU 41 and a programmable ROM (PRO
M) 43, a RAM 44, and a character generator (CG) 45 storing a character dot matrix. The control circuit 40 further includes an I / F dedicated circuit 50 dedicated to interface with an external motor or the like, and a head connected to the I / F dedicated circuit 50 to drive the print head unit 60 to eject ink. A drive circuit 52 and a motor drive circuit 54 for driving the paper feed motor 22 and the carriage motor 24 are provided. The I / F dedicated circuit 50 has a built-in parallel interface circuit.
6, the print data PD supplied from the computer 90 can be received. The color printer 20
Printing is performed according to the print data PD. Note that R
The AM 44 functions as a buffer memory for temporarily storing raster data.

The print head unit 60 includes the print head 2
8 and an ink cartridge can be mounted. The print head unit 60 is attached to and detached from the color printer 20 as one component. That is, when the print head 28 is to be replaced, the print head unit 60 is replaced.

FIG. 4 is a perspective view of the lower surface of the print head 28.
It is explanatory drawing which shows a chisel arrangement. On the lower surface of the print head 28
Is the dark black ink for discharging the dark black ink.
Nozzle group K_D And for ejecting light black ink
Light black ink nozzle group K _L And eject the dark cyan ink
Dark cyan ink nozzle group C for printing_D And light cyan
Light cyan ink nozzle group C for discharging ink_L 
And dark magenta ink for discharging dark magenta ink
Nozzle group M_D To discharge light magenta ink
Light magenta ink nozzle group M_L And dark yellow ink
Dark yellow ink nozzle group Y for discharging_D And light
Light yellow ink nozzle for discharging yellow ink
Group Y_L Are formed. Here, dark ink and light ink
Is different from at least one of lightness and saturation, and the hue is
Almost the same ink.

The light ink nozzle group is shifted from the dark ink nozzle group in the sub-scanning direction. Here, the capital letter of the first alphabet in the code indicating each nozzle group means the ink color, and the suffix “D” indicates that the ink has a relatively high density, and the suffix “L” Means that the ink has a relatively low density.

A 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 (referred to as “dot pitch”) corresponding to the printing resolution in the main scanning direction and 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 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 driving element for driving each nozzle to eject ink droplets. When printing, print head 2
While the nozzle 8 moves in the main scanning direction MS, ink droplets are ejected from each nozzle.

The plurality of nozzles in each nozzle group need not be arranged in a straight line along the sub-scanning direction.
For example, they may be arranged in a staggered manner. Note that even when the nozzles are arranged in a staggered manner, the nozzle pitch kD measured in the sub-scanning direction can be defined in the same manner as in the case of FIG. In this specification, the phrase "a plurality of nozzles arranged along the sub-scanning direction" has a broad meaning that includes nozzles arranged in a straight line and nozzles arranged in a staggered manner. I have.

FIG. 5 is an explanatory view showing another example of the nozzle arrangement on the lower surface of the print head 28. As shown in FIG. The difference from the nozzle arrangement shown in FIG. 4 is that the dark ink nozzle group and the light ink nozzle group are not shifted in the main scanning direction. That is, these nozzle groups are arranged in a line in the sub-scanning direction and are arranged in the print head. However, with respect to the sub-scanning direction, the nozzle arrangement is shifted similarly to the nozzle arrangement shown in FIG. Note that there is an advantage that the print head 28 can be made smaller by arranging the dark ink nozzle group and the light ink nozzle group in a line in the sub-scanning direction.

In the color printer 20 having the above-described hardware configuration, the carriage 30 is reciprocated by the carriage motor 24 while the paper P is conveyed by the paper feed motor 22, and at the same time, the piezo elements of the print head 28 are driven. By discharging ink droplets of each color, ink dots are formed to form a multi-color and multi-tone image on the paper P.

B. Basic conditions of recording method: Before describing the details of the recording method used in the embodiment of the present invention, first, basic conditions of a normal interlace recording method will be described below. The “interlace recording method” refers to a recording method adopted when the nozzle pitch k [dot] measured along the sub-scanning direction of the print head is 2 or more. In the interlace printing method, a raster line that cannot be printed remains between adjacent nozzles in one main scan, and pixels on this raster line are printed during another main scan. In this specification, the terms “printing method” and “recording method” are synonymous.

FIG. 6 is an explanatory diagram showing basic conditions of a normal interlace recording system. FIG. 6 (A)
FIG. 6B shows an example of sub-scan feed when four nozzles are used, and FIG. 6B shows parameters of the dot recording method. In FIG. 6A, solid-line circles including numbers indicate the positions of 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 22 (FIG. 2).

As shown in the left end of FIG. 6A, 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. 6A, 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. 6B shows various parameters relating to the dot recording method. 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. 6, 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. 6, 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. 6B 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 (position in every four dots in FIG. 6) is a 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. 6A, 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. 6A). 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. 6, when the position of the nozzle is located at an integer multiple of the nozzle pitch k from the initial position, 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 has 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.

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 one cycle of sub-scan feed is k times,
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. 6A, the nozzle position after one cycle (after k sub-scan feeds) is shifted from the initial nozzle position by N × k raster lines. 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.

FIG. 7 is an explanatory diagram showing the basic conditions of the dot recording method 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 (B), the number of scan repetitions s and the sub-scan feed amount L are changed. As can be seen from FIG. 7A, the sub-scan feed amount L in the dot recording method in FIG. 7 is a constant value of 2 dots. However, in FIG. 7A, the positions of the nozzles in the even-numbered passes are indicated by diamonds. Normally, FIG.
As shown at the right end of the figure, the dot positions recorded in the even-numbered pass are the dot positions recorded in the odd-numbered pass,
It is shifted by one dot in the main scanning direction. 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 0th nozzle in pass 5. Is done. In the overlap method, the nozzles are driven at intermittent timings so that (s-1) dot printing is prohibited after printing one dot during one main scan.

The overlap method in which intermittent pixel positions on a raster line are recorded at the time of each main scan is called an "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 scans are performed on one raster line, dot overprinting may be allowed at the same pixel position. Such an overlap method is referred to as “overlap overlap method” or “complete overlap method”.

In the intermittent overlap method, since the positions of a plurality of nozzles for recording the same raster line in the main scanning direction only need to be shifted from each other, the actual shift amount in the main scanning direction at each main scanning is: Various things other than the thing 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.

At the bottom of the table in FIG. 7B, the value of the offset F of each path in one cycle is shown. 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 in 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 one. Therefore, condition c
1 ′ to c3 ′ are considered to be conditions generally satisfied for the interlaced recording method regardless of the value of the number of scan repetitions s. That is, the above three conditions c
If 1 ′ to c3 ′ are satisfied, it is possible to prevent missing or unnecessary duplication of dots to be recorded in the effective recording range. However, when 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 employing the overlap printing method, it is sufficient that the above-mentioned conditions c1 'to c3' are satisfied, and all pixel positions are to be recorded in each pass.

C. The concept of multi-gradation by using a plurality of inks having different shades: FIG. 8 is an explanatory diagram showing a dot recording method used for high-resolution normal printing.
In FIG. 8, solid-line circles including numbers indicate the positions of the six nozzles in the sub-scanning direction in each pass. Two-digit numbers 00 to 12 in the circles indicate nozzle numbers.
The upper digit of this number is a number that identifies the nozzle group,
The lower digit is a number for specifying a nozzle in the nozzle group. Nozzles whose upper digit of the nozzle number is 0 are nozzles of a nozzle group that discharges dark ink, and nozzles whose upper digit of the nozzle number is 1 are nozzles of a nozzle group that discharges light ink. Here, it is assumed that the print head has three dark ink nozzles 00 to 02 and three light ink nozzles 10 to 12.

The pixel position numbers shown at the right end of FIG. 8 indicate the order of arrangement of pixels on each raster line, and the numbers in circles indicate the numbers of the nozzles responsible for forming dots at that pixel position. I have. For example, the first raster line can be dots by both nozzles # 02 and # 10. That is, the first raster line is formed by the nozzle # 01 when forming a dark color dot, and formed by the nozzle # 10 when forming a light color dot. Further, by forming dots on the same pixel in a superimposed manner by both nozzles, a pixel with a higher color density can be formed. Similarly, the dot on the second raster line is # 00
The nozzles on the third raster line are formed by the nozzles # 01 and # 12. Generally, the (1 + 3 × n) -th raster line is # 0
For nozzles 2 and # 10, the (2 + 3 × n) th raster line is for nozzles # 00 and # 11 and (3 + 3 × n)
The n) th raster line is formed by nozzles # 01 and # 12. Here, n is a non-negative integer.

A group of nozzles (00 to 0) for discharging dark ink
This recording method will be described focusing on 2). As shown in FIG. 8, in this example, the sub-scan feed amount L is a fixed value of 3 dots, and the effective nozzle number Neff of each nozzle group is 3. Other parameters of this recording method are k = 4,
s = 1. These parameters correspond to the condition c described above.
1 ′ to c3 ′ are satisfied. Therefore, printing can be performed without missing or unnecessary duplication of dots to be recorded for each nozzle group. Therefore, it is also possible to form dots only by nozzle groups that eject dark ink to pixels of all raster lines. On the other hand, the same applies to the nozzle group that discharges light ink (the upper digit of the nozzle number is 1).

As can be seen from the above description, both the nozzle group that discharges dark ink and the nozzle group that discharges light ink can form dots in the same pixel. Thereby, dots using at least one of the dark ink and the light ink can be formed for each pixel, and multi-gradation can be achieved. In other words, it is possible to select dark ink or light ink or both used to form dots in the same pixel, thereby increasing the gradation of each pixel and improving image quality.

D. Concept of Print Data and Sub-scan Feeding in Draft Printing: FIG. 9 is a diagram for explaining recording target pixels of each nozzle in normal printing and draft printing. In FIG. 9, the dot pitch Dn in normal printing corresponds to the printing resolution of normal printing. On the other hand, the dot pitch Dd in draft printing corresponds to the printing resolution of draft printing. Further, these dot pitches Dn, Dd
Is a reference value of the nozzle pitch k and the sub-scan feed amount L in normal printing and draft printing.

In high-resolution normal printing, the dot pitch D
Since n is relatively small, the recording target pixel of each nozzle is also small. For this reason, it can be seen that the number of pixels to be recorded increases with respect to a print medium having the same area, and many dots are required for printing. On the other hand, in low-resolution draft printing, since the dot pitch Dd is relatively large, the recording target pixel of each nozzle is also large. More specifically, the pixels to be recorded in the draft printing are the same as those of the normal printing in terms of area.
Doubled. Therefore, it can be seen that printing can be performed with a small number (1/4) of dots because the number of pixels to be recorded is small on a print medium having the same area. Therefore, from the viewpoint of the number of formed dots only, draft printing can be performed at four times the speed of normal printing. This is because the printing speed is inversely proportional to the number of dots required for printing, assuming that the number of dots formed per unit time is constant. The four times printing speed is realized by, for example, doubling the main scanning speed and doubling the sub-scan feed amount L.

E. Comparative Example and Example of Dot Recording Method in Draft Printing: FIG. 10 is an explanatory diagram showing a first comparative example of the conventional draft printing. The difference from the normal printing shown in FIG. 8 is that the dot pitch Dd is twice as large as Dn. Therefore, as described above, both the main scanning speed and the sub-scan feed amount L can be doubled. However, since the recording density is low, the image quality is degraded.

The dot recording method of the first comparative example will be described focusing on only one of the dark ink nozzle and the light ink nozzle. The parameter of this recording method is Neff =
3, k = 2Dd (= 4Dn), L = 3Dd (= 6D
n), s = 1. These parameters satisfy the above-described conditions c1 ′ to c3 ′. Therefore, printing can be performed without missing or unnecessary duplication of dots to be recorded.

FIG. 11 is an explanatory diagram showing a dot recording method according to the first embodiment of the present invention. The difference from the first comparative example shown in FIG. 10 is that dots are formed on main scanning lines in which the dark ink nozzle group and the light ink nozzle group are different.
The point is that dots are not formed on the same main scanning line. That is, in the first comparative example shown in FIG. 10, the nozzle group that discharges the dark ink and the nozzle group that discharges the light ink can form dots on the same main scanning line. However, in the first embodiment, both nozzle groups independently form dots on different main scanning lines. Therefore, the effective nozzle number Nef
As f is increased from 3 to 6, the effective nozzle pitch k becomes 1Dd, and the raster lines formed by one main scan (also called “pass”) come into close contact with each other. As a result, there is no need to perform sub-scan feed in the interlaced mode, and band feed is possible. Here, the “band feed” refers to a value of a length measured along the sub-scanning direction in an area formed by an array of dots that can be formed by a plurality of the same hue nozzle groups in a single main scan. This means that the scanning feed amount L is set and sent.

The improvement in the printing speed of the first embodiment will be described from the viewpoint of the number of main scanning lines recorded per unit time. The number of main scan lines recorded per unit time is the product of the number of main scans per unit time and the number of effective nozzles Neff. In the first comparative example, since the dark ink nozzles and the light ink nozzles are used for recording the same main scanning line, the printing speed is the same as the printing method using only the dark ink nozzles. On the other hand, in the first embodiment, all the nozzles can print a different number of main scan lines, so that all the nozzles do not record in a superimposed manner and do not pause the recording. Each of the above pixels can be recorded. As a result, in the first embodiment, the number of main scan line recordings per unit time is twice that of the first comparative example, and the printing speed is also doubled accordingly. The increase in the printing speed is specifically achieved by doubling the sub-scan feed amount L.

In the first embodiment, print data PD for draft printing is used. This is because the method of using the nozzles and the main scanning speed and the sub-scan feed amount L are different from those in normal printing.

FIG. 12 is a flowchart showing a procedure for generating print data PD for draft printing by the printer driver. In this procedure, print data PD for draft printing is directly generated from RGB image data.
Specifically, in step S1, the printer driver 96 (FIG. 1) performs color conversion based on four-color inks instead of color conversion based on eight inks performed in normal printing. This color conversion is performed by the color conversion module 98 (FIG. 1).
However, the conversion is performed by converting the RGB image data for each pixel into multi-color data of four colors with reference to the color conversion table LUT for draft printing. At step S2, the halftone module 99 (FIG. 1) performs halftone processing on the color-converted multi-tone data. In the halftone processing, the average density of inks having different densities may be considered. Specifically, for example, by setting a threshold value used in the halftone process on the basis of the average density of the dark ink and the light ink, the halftone process considering the average density of the ink is realized. The halftone data generated by the halftone processing is rasterized by the rasterizer 100 (FIG. 1) in step S3, and print data PD for draft printing is generated. Here, "rasterizing" refers to a process of converting halftone data into print data PD so that printing can be performed using a print head while scanning in the main scanning direction and the sub-scanning direction. The rasterized print data PD includes raster data indicating a dot recording state during each main scan and data indicating a sub-scan feed amount.

FIG. 13 is a flowchart showing another procedure for creating print data PD. In this procedure, print data PD for draft printing is generated by converting halftone data generated through color conversion and halftone processing on the assumption of eight color inks performed in normal printing. Specifically, the printer driver 96 (FIG. 1)
In step S1, referring to the color conversion table LUT for normal printing, color conversion is performed on the assumption that eight colors of ink are used in normal printing. The color-converted multi-tone data is
In step S2, the halftone module 99
Halftone processing is performed by (FIG. 1). In this halftone process, similarly to the case where halftone data for draft printing is directly generated from RGB image data,
The average density of the different density inks is taken into account. The halftone data generated by the halftone process is subjected to data conversion in step S3. This data conversion is a process for performing a logical sum of halftone data of dark ink and halftone data of light ink for each main scanning line. In step S4, the converted halftone data is rasterized to generate print data PD for draft printing.

FIG. 14 is a table showing the contents of the processing for converting the normal print data PD into the draft print data PD. A method for converting print data PD for normal printing and generating print data PD for draft printing using this table will be described. The raster of raster number 1 is formed by pass 1 and pass 2 in the first comparative example for normal printing, and is formed only by pass 1 in the first embodiment. Therefore, in the first comparative example, the raster data of the nozzle # 11 in the pass 1 and the raster data of the nozzle # 00 in the pass 2 are used to form the raster of the raster number 1. These two nozzles scan the same pixel in a superimposed manner and are used selectively or superposedly. On the other hand, this first
In the embodiment, printing is performed only with raster data of nozzle # 00 in pass 1. Therefore, in order to generate the raster data used in the first embodiment from the raster data in the first comparative example, in the comparative example, the nozzle # 11 in pass 1 and the nozzle # 0 in pass 2 with the pixel to be printed in pass 1
It is necessary to generate raster data to be printed at any pixel where 0 is printed. Therefore, it can be seen that the raster data used in the first embodiment should be the logical sum of the raster data of the two nozzles used in the first comparative example.

The above processing may be partially or entirely performed by the printer driver of the computer 90, or may be performed by the printer firmware of the color printer 20. When using printer firmware,
This is performed by the control circuit 40 (FIG. 3). The data sent from the computer 90 is processed by the CPU 41 using the firmware stored in the P-ROM 43.

FIG. 15 is an explanatory diagram showing a dot recording method according to the second embodiment of the present invention. The difference from the first embodiment shown in FIG. 11 is that the number of nozzle groups is increased from two to three. In this embodiment, a print head using three kinds of inks having different densities is assumed for further increasing the number of gradations. That is, the head is equipped with a nozzle group of three types of inks having different densities for one hue. Specifically, for example, nozzles # 00, 01, and 02 eject high-density ink, nozzles # 10, 11, and 12 eject medium-density ink, and nozzles # 20, 21, and 22 eject low-density ink. It is.

In the second embodiment, the number of effective nozzles Neff is increased from 3 to 9 and the nozzle pitch k is 1Dd as compared with the conventional draft printing.
Therefore, the rasters formed in one pass come into close contact with each other. As a result, it is not necessary to perform the sub-scan feed by the interlace method, and the band feed can be performed similarly to the first embodiment, and the printing speed is greatly improved. The number of rows of the nozzle group is not limited, and the same can be applied to four or more rows.

FIG. 16 is a diagram showing a second example of the conventional draft printing.
FIG. 9 is an explanatory diagram illustrating a dot recording method of a comparative example. The difference from the first comparative example shown in FIG. 10 is that the nozzle pitch k is 2Dd.
Is increased to 4Dd. The parameters of this printing method are Neff = 3 for each density nozzle group.
k = 4Dd (= 8Dn), L = 3Dd (= 6Dn), s
= 1. These parameters correspond to the condition c described above.
1 ′ to c3 ′ are satisfied. Therefore, each nozzle group
Printing can be executed without missing or unnecessary duplication of dots to be recorded.

FIG. 17 is an explanatory diagram showing a dot recording method according to the third embodiment of the present invention. The difference from the second comparative example shown in FIG. 16 is similar to the difference between the first comparative example and the first embodiment.
The difference is that the dark ink nozzle group and the light ink nozzle group form dots on different main scanning lines. However,
In the third embodiment, although the effective nozzle number Neff increases from 3 to 6, the nozzle pitch k does not become 1Dd.
This is different from the first embodiment shown in FIG. The parameters of this recording method are Neff = 6, k = 2Dd (= 4Dn), L
= {5Dd-7Dd} (｝ L / k = 6Dd), s = 1. Here, the average sub-scan feed amount (ΣL / k) matches the product of the dot pitch Dd in draft printing and the effective nozzle number Neff, and satisfies the condition c3 ′. In the third embodiment, since the sub-scan feed amount L is twice that of the second comparative example, the printing speed is also twice.

In the third embodiment, as described above, since the nozzle pitch k does not become 1Dd, band feeding cannot be performed. For this reason, the interlaced system is used. The sub-scan feed of this embodiment is an irregular feed in which {5Dd, 7Dd} is repeated as the feed amount as shown in FIG. The reason why the regular feed (sub-scan feed in which the feed amount is constant) is not performed is that if the regular feed is used, the sub-scan feed amount L (6D
d) is an integral multiple of the nozzle pitch k (2Dd),
The offset of the nozzle after the sub-scan feed is constantly 0. Therefore, the condition c2 'that the nozzle offset F after each sub-scan feed in one cycle is a value in the range of 0 to (k-1) and that each value is repeated s times. This is because they will not be satisfied. On the other hand, if the sub-scan feed is an irregular feed of 5Dd-7Dd, the offset F of the nozzle after each sub-scan feed in one cycle is:
0 and 1 are alternately repeated. Therefore, this recording method satisfies the condition c2 ', constitutes one cycle with two sub-scan feeds, and simultaneously satisfies the condition c1'. Accordingly, by using the sub-scan feed, it is possible to satisfy all of the conditions c1 ′ to c3 ′ and execute printing without missing or unnecessary duplication of dots to be recorded.

FIG. 18 is an explanatory diagram showing a dot recording method according to the fourth embodiment of the present invention. The difference from the third embodiment shown in FIG. 17 is the mutual positional relationship of each nozzle group. That is, in the third embodiment, the shift in the sub-scanning direction between the nozzle group that discharges the dark ink and the nozzle group that discharges the light ink is half the nozzle pitch of the nozzle group. In the embodiment, they are arranged at positions deviated from half. The amount of this shift is 1Dd so that the rasters formed by the nozzle groups are in close contact with each other.

In the fourth embodiment, since the nozzle groups are shifted so that the rasters formed by the nozzle groups are in close contact with each other, it is necessary to consider two adjacent dark and light nozzles as one nozzle. Is also possible. Specifically, as shown in FIG. 18, # 00 and 10, # 01 and 1
The nozzles # 1, # 02 and # 12 are each shifted in the sub-scanning direction by 1Dd, so their rasters are in close contact and can be considered as one nozzle unit.
Then, the recording target pixel of this nozzle unit can be considered based on the recording target pixel of normal printing,
The number is four for the sub-scanning direction and two for the main scanning direction. As a result, the parameter of this recording method is Neff =
3 units, k = 2Dd, L = 3Dd (= 12Dn),
s = 1. These parameters correspond to the condition c described above.
1 ′ to c3 ′ are satisfied. Accordingly, it can be seen that printing can be performed without missing or unnecessary duplication of dots to be recorded.

FIG. 19 is an explanatory diagram showing a dot recording method according to the fifth embodiment of the present invention. The difference from the fourth embodiment shown in FIG. 18 is that the number of nozzle groups is increased from two to three. Further, the difference from the second embodiment shown in FIG.
The second embodiment is different from the second embodiment in that the band is fed, but the interlace recording method is used. In this embodiment, as in the fourth embodiment, # 00, 10, and 20, # 01
The nozzles # 11, # 21, # 02, # 12, and # 22 are displaced by 1 Dd in the sub-scanning direction, and their rasters are in close contact with each other, and can be considered as one nozzle unit. And the parameters of this recording method are
It is the same as in the embodiment, and it can be seen that printing can be executed without missing or unnecessary duplication of recorded dots.
As a result, if the nozzle groups can be formed by shifting the nozzle groups by 1Dd in the sub-scanning direction to form raster lines that are in close contact with each other, by satisfying the conditions c1 ′ to c3 ′ based on the nozzle units, The operation can be performed with four or more groups.

FIG. 20 is an explanatory diagram showing a dot recording method according to the sixth embodiment of the present invention. The difference from the third embodiment shown in FIG. 17 is that the number of nozzle groups is increased from two to three. The parameters of this recording method are Neff = 9, k
= 2Dd, L = 9Dd (= 18Dn), and s = 1.
These parameters satisfy the above-described conditions c1 ′ to c3 ′. That is, even in the case of three rows, as in the case of the two rows, printing can be performed without missing or unnecessary duplication of dots recorded by regular feeding. In addition,
It is apparent that there is no limitation on the rows of the nozzle groups, and the same can be achieved with four or more rows as long as the conditions c1 ′ to c3 ′ are satisfied.

The present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist thereof.
For example, the following modifications are possible.

The present invention can be applied not only to color printing but also to monochrome printing. Further, the present invention can be applied to a drum printer. In the drum printer, the drum rotation direction is the main scanning direction, and the carriage traveling direction is the sub scanning direction. Further, the present invention is not limited to an ink jet recording apparatus,
In general, the present invention can be applied to a dot recording apparatus that performs recording on the surface of a print medium using a recording head having a plurality of dot forming element arrays. Here, "dot forming element"
Means a component for forming dots, such as an ink nozzle in an ink jet printer.

In the above embodiment, a part of the configuration realized by hardware may be replaced by software. Conversely, a part of the configuration realized by software may be replaced by hardware. Is also good. For example, some or all of the functions of the printer driver 96 shown in FIG. 1 may be executed by the control circuit 40 in the printer 20. In this case, some or all of the functions of the computer 90 as a print control device for creating print data may be performed by the printer 20.
Is realized by the control circuit 40 of FIG.

When a part or all of the functions of the present invention are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, "a computer-readable recording medium"
The term “not only includes portable storage media such as a flexible disk and a CD-ROM, but also includes internal storage devices in a computer such as various RAMs and ROMs and external storage devices fixed to the computer such as a hard disk. In.

In the embodiment of the present invention, a printing method using eight or twelve kinds of inks as four hue inks has been described. However, the applicable range of the present invention is not limited to these cases, and N (N
Is a positive integer, and M kinds of inks (M is N +
It can also be applied to a printing method using an ink of (an integer of 1 or more).

[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.

FIG. 3 shows a color printer 20 mainly including a control circuit 40.
FIG.

FIG. 4 is an explanatory diagram showing a nozzle arrangement on a lower surface of a print head.

FIG. 5 is an explanatory diagram showing another example of the nozzle arrangement on the lower surface of the print head.

FIG. 6 is an explanatory diagram showing basic conditions of a normal interlace recording method.

FIG. 7 is an explanatory diagram showing basic conditions of the overlap recording method.

FIG. 8 is an explanatory diagram showing a dot recording method which is a high-resolution normal printing.

FIG. 9 is an explanatory diagram showing recording target pixels of each nozzle in normal printing and draft printing.

FIG. 10 is an explanatory diagram showing a first comparative example which is a conventional draft printing.

FIG. 11 is an explanatory diagram showing a dot recording method according to the first embodiment of the present invention.

FIG. 12 is a flowchart illustrating a procedure for generating print data PD for draft printing by a printer driver.

FIG. 13 is a flowchart illustrating another procedure for creating print data PD.

FIG. 14 is a process for converting print data PD for normal printing into print data PD for draft printing.

FIG. 15 is an explanatory diagram showing a dot recording method according to a second embodiment of the present invention.

FIG. 16 is an explanatory diagram showing a second comparative example of the conventional draft printing.

FIG. 17 is an explanatory diagram showing a dot recording method according to a third embodiment of the present invention.

FIG. 18 is an explanatory diagram showing a dot recording method according to a fourth embodiment of the present invention.

FIG. 19 is an explanatory diagram showing a dot recording method according to a fifth embodiment of the present invention.

FIG. 20 is an explanatory diagram showing a dot recording method according to a sixth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 20 color printer 21 CRT 22 paper feed motor 24 carriage motor 26 platen 28 print head 30 carriage 32 operation panel 34 sliding shaft 36 drive belt 38 pulley 39 position sensor 40 control circuit 41 ... CPU 43 ... ROM 44 ... RAM 50 ... I / F Dedicated Circuit 52 ... Head Drive Circuit 54 ... Motor Drive Circuit 56 ... Connector 60 ... Print Head Unit 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 (8)

[Claims] 1. Print data to be supplied to a printing unit for performing printing using a printing unit that forms dots on a printing medium while scanning a printing head that ejects a plurality of types of inks in a main scanning direction. Wherein the print head comprises a plurality of identical hue nozzle groups for ejecting a plurality of identical hue inks having substantially the same hue and different in at least one of lightness and chroma, and The hue nozzle groups are arranged at positions shifted from each other along the sub-scanning direction, and the print control device is configured such that when performing printing in a predetermined high-speed print mode, the plurality of same hue nozzle groups are different from each other. A print data generating unit for generating the print data for performing printing so that a main scanning line is a recording target and the same main scanning line is not a recording target. Apparatus. 2. The print control apparatus according to claim 1, wherein the print head uses M (M is an integer equal to or greater than N + 1) inks as N (N is a positive integer) hue ink. The print data generation unit is capable of discharging, and the color conversion unit generates color conversion image data represented by a plurality of color components by converting a color system of given image data; and A halftone processing unit that generates halftone data for the plurality of color components by performing a halftone process on the image data; and a discharge state of ink from each nozzle during each main scan from the halftone data. A rasterizer that generates raster data representing the same as the print data, wherein the color conversion unit classifies the plurality of same hue inks in the high-speed print mode. Generating color conversion image data represented by the N hue color components without distinction;
Print control device. 3. The print control device according to claim 1, wherein the print head uses M (M is an integer equal to or greater than N + 1) inks as N (N is a positive integer) hue ink. The print data generation unit generates color conversion image data represented by M kinds of color components corresponding to the M kinds of inks by converting a color system of the given image data. A halftoning unit that performs halftone processing on the color-converted image data to generate halftone data for the M types of color components; Among the halftone data for the M types of color components on the scanning line, the logical sum of the halftone data for a plurality of color components corresponding to the plurality of same hue inks is calculated. A halftone data conversion unit that generates halftone data represented by the N hue color components, and indicates a discharge state of ink from each nozzle during each main scan from the halftone data. A print control device comprising: a rasterizer that generates raster data as the print data. 4. The print control apparatus according to claim 1, wherein the print head uses M (M is an integer equal to or greater than N + 1) inks as N (N is a positive integer) hue ink. The print data generation unit generates color conversion image data represented by M kinds of color components corresponding to the M kinds of inks by converting a color system of the given image data. A halftone processing unit that performs halftone processing on the color-converted image data to generate halftone data for the plurality of color components. A rasterizer that generates, as the print data, raster data representing the state of ink ejection from each nozzle in the high-speed print mode. By taking the logical sum of the raster data of a plurality of color components corresponding to the plurality of same hue inks among the raster data of the above M kinds of color components, the raster data is represented by the N hue color components. And a color synthesizing unit for generating raster data. 5. The print control apparatus according to claim 1, wherein the plurality of same hue nozzle groups are arranged in a line in a sub-scanning direction. 6. The print control device according to claim 1, wherein the print data is a sub-scan feed amount for feeding one of the print head and a print medium in a sub-scan direction. In the high-speed print mode, the sub-scan feed amount measures an area formed by an array of dots that can be formed by the plurality of same hue nozzle groups in one main scan along the sub-scan direction. The print control set to the length value. 7. A printing apparatus for performing printing by forming dots on the surface of a printing medium, comprising: a plurality of identical inks that eject a plurality of identical hue inks having substantially the same hue and differing in at least one of brightness and saturation. A plurality of hue nozzle groups, the plurality of same hue nozzle groups are arranged at positions shifted from each other along the sub-scanning direction, and a print head that ejects a plurality of types of inks is scanned on a print medium while scanning in the main scanning direction. A printing unit for forming dots; a print control device according to claim 1;
A printing device comprising: 8. A plurality of identical hue nozzle groups for ejecting a plurality of identical hue inks having substantially the same hue and different in at least one of lightness and saturation, wherein the plurality of identical hue nozzle groups are arranged along the sub-scanning direction. A computer for causing a computer to generate print data to be supplied to a printing unit that forms dots on a print medium while scanning a print head that ejects a plurality of types of inks in a main scanning direction and that is arranged at positions shifted from each other. A computer-readable recording medium on which a program is recorded, wherein when performing printing in a predetermined high-speed print mode, the plurality of same hue nozzle groups are recorded on different main scanning lines, and the same The computer has a function of generating the print data for printing so that the main scanning line of the Computer readable recording medium having a program for implementing.